Titan Rover Senior Design Project Critical Design Review 2021

1
EGME 419: Spring 2021 Final Report
Titan Rover 2020-2021
Systems Overview
Project Co-Lead - Kit Kerames
Project Co-Lead - Van Nguyen
Robotics Lead - Sasha Licari
Drivetrain Lead - Houston Tong
Manufacturing/Chassis - Axel Alvarez L.
Science Lead - Axel Alvarez L.
Tony Nguyen, Juan Alvarado, Haley Choi,
Daniel Velazquez, Jonathan Tang, Austyn
Webster, Ajit Singh, Adrian Throckmorton,
Kevin Tran, Lily Park
Submit to Dr. Robson
May 20th, 2021

2
Table of contents
List of Figures .............................................................................................................................. 3
List of Tables ................................................................................................................................ 4
1.0 Abstract .................................................................................................................................. 5
2.0 Objectives ............................................................................................................................... 6
2.1. System Acceptance Review: ..................................................................................................6
2.2 Equipment Servicing Mission: ............................................................................................. 7
2.3 Autonomous Navigation Mission ......................................................................................... 7
2.4 Science Mission:.......................................................................................................................8
2.5 Extreme Retrieval and Delivery Mission: ........................................................................... 9
3.0 Background............................................................................................................................. 9
4.0 Technical Approach ....................................................................................................... 11-12
4.1 Refer to Robotics: Technical Volume 01 ........................................................................... 11
4.2 Refer to Mobility: Technical Volume 02 ........................................................................... 11
4.3 Refer to Chassis: Technical Volume 03 ..............................................................................12
4.4 Refer to Science: Technical Volume 04 .......................................................................... ...12
5.0 Team Structure ...............................................................................................................13-14
6.0 Timeline ................................................................................................................................15
7.0 Budget ..............................................................................................................................16-17
8.0 ABET Requirements ......................................................................................................18-22
References ...................................................................................................................................23
Appendix……………………………..……………………………………………………...24-26

3
List of Figures
Figure 1: Rover on a mission during URC 2015……………………………………………………….…..5
Figure 2: URC 2019: Equipment Servicing Mission………………………..………………………….…..7
Figure 3: URC 2016: Autonomous Navigation Mission…………….…………...…………………….…..8
Figure 4: URC 2019: Science system assembled and onboard………………………………………....…..8
Figure 5: URC 2019: Extreme Retrieval and Delivery Mission………………………………………..…..9
Figure 6: Odyssey’s Science Configuration……………....………………………………………….…....10
Figure 7: Timing Belt Assembly……………………………………………………………………....…..11
Figure 8: Suspension System……………………………………………………………………….….….11
Figure 9: Layout of the Chassis ……………………………………………………………...…….….….12
Figure 10: Science system with Geneva gear system……………………………...……………….….….12
Figure 11: Mechanical team structure ………………………………………………………………....….13
Figure 12: Competition year schedule ………………………………………………………………...….15

4
List of Tables
Table 1: Possible scores for each URC mission……………………………………………………...……6
Table 2: ABET Requirements……………………………………………………………………….……20

5
3.0 Abstract
Titan Rover’s objective this year was to design, manufacture, and test a teleoperated Mars Exploration
Rover to represent California State University Fullerton in the 2022 University Rover Challenge. The
rover’s electromechanical design consists of a versatile suspension system, robotic arm, electrical
power/signals distribution system, communications system, controls user interface and science cache.
Unfortunately, the team did not get a chance to work on the rover physically this year. We had the chance
to redesign key systems and perform research on new design concepts and improvements for the following
year to come. For example, the robotic features a redesign of the Odyssey robotic arm and a brand new
roller chain system. Improvements were also made on the grippers to utilize current industry materials in
order to achieve the best grip. The biggest improvements that was done on the rover was the mobility sub-
system. A new suspension system was designed, including the shock mounting position and control arms
design. Another major change was the implementation of the all new 3D printed tires and hub system. This
allows the team to manufacture our tires and wheel hubs in house with ease of manufacturability in mind.
This design allows more space to be utilized inside the chassis for other components. Other additions
include a chassis stand attached to the rover for weighing vertically, as well as a folding antenna mass.
This allows the team to make the chassis size longer for a better center of gravity and more space for
components. Our current rover model can be seen below compared to previous years’ rovers. Overall, the
team took advantage of the pandemic to work on designs and development for the team in hopes of pushing
next year’s competition team to perform well.
Figure 1: Current CAD design of year 2021 Titan Rover team

6
Figure 2: Odyssey Rover 2019
Figure 3: Kronos Rover 2020

7
2.0 Objectives
Titan Rover’s objective is to design and produce a competitive, semi-autonomous robotic system that falls
within the parameters of the University Rover Challenge (URC) competition. The URC challenges students
to build semi-autonomous rovers that can accomplish a variety of tasks, and that may one day assist
astronauts working on the surface of Mars. Competition tasks are executed in the following missions.
● Science Mission
-Rover must analyze soil to look for signs of life.
● Extreme Retrieval and Delivery Mission
-Rover picks up and delivers objects in the field.
● Equipment Servicing Mission
-Rover performs maintenance tasks on a variety of equipment.
● Autonomous Traversal Mission
-Rover autonomously traverses rocky, Mars-like terrain.
Table 1: Possible scores for each URC mission
Event / Task Points Possible:
System Acceptance Review (SAR) 100
Equipment Servicing Mission 100
Autonomous Traversal Mission 100
Science Cache Mission 100
Extreme Retrieval and Delivery Mission 100
During each competition year, Titan Rover is required to submit several milestone reviews to certify the
team’s readiness for competition. First of all, a declaration of Intent to Compete, a Preliminary Design
Review (PDR) and a System Acceptance Review (SAR). Titan Rover’s score within each mission is
dependent on a series of Mission-milestones, briefly described below:
2.1 System Acceptance Review: Titan Rover must deliver a technical report and video which focuses on
the overall system design, science plan, and progress-to-date of the final system; Titan Rover’s SAR
package will be judged against other teams’ submissions by URC judges. The top 36 scoring teams will be
invited to compete in the field.
2.2 Equipment Servicing Mission: The rover must traverse up to one quarter kilometer from its base
station to carry a minor payload to an analogous lander where, upon delivering the payload, it must perform
a series of finesse tasks to include operating a control panel (i.e. flipping switches, twisting dials, pushing
buttons), using tools such as a screwdriver, open and closing lander compartments and typing on a
keyboard.

8
Figure 2: URC 2019: Equipment Servicing Mission
2.3 Autonomous Navigation Mission: The rover will be required to autonomously traverse across
moderate terrain, performing real time obstacle detection/avoidance on its way to a series of markers in
two stages; Each stage will consist of three to four legs. For each leg, judges will provide GPS coordinates;
at an unspecified distance from coordinates provided will be a post with a 20cm x 20cm AR tag elevated
off the ground which the rover must identify before proceeding to the next stage. Failure to complete a
stage in the allotted time ends the mission.
Figure 3: URC 2016: Autonomous Navigation Mission
2.4 Science Mission: Using its on-aboard instrumentation package, the rover will collect soil samples at
sites selected in the field and conduct in-situ analysis; searching for indicators that determine the absence
or presence of life; either extinct or extant. Furthermore, each site will be analyzed for the likelihood of
supporting microbial life using a geological context (i.e. evidence of water flow, minerals present, and soil
structure).

9
Figure 4: URC 2019: Science system assembled and onboard
2.5 Extreme Retrieval and Delivery Mission: The rover will be required to collect a series of objects in
the field and deliver them to designated locations; providing service to fallen astronauts. This task requires
the rover to traverse multiple types of terrain and operate no more than one kilometer beyond line of sight
in the allotted time frames. Approximate GPS coordinates are provided and objects to be retrieved involve
fuel canisters, toolboxes, lightweight tools, or rock specimens. This task consists of a series of stages and
failure to complete a stage ends the task.
Figure 5: URC 2019: Extreme Retrieval and Delivery Mission
The missions outlined above define the system requirements of Titan Rover’s platform. In addition to
addressing these objectives, the system must also meet general constraints of the URC, defining the
maximum system weight, cost, and communication parameters.

10
3.0 Background
Titan Rover has represented Cal State Fullerton’s School of Engineering and Computer Science
by competing numerous times in the URC; unfortunately, 2020’s competition was canceled. The 2020
rover platform, Kronos, featured a double-wishbone, inboard pneumatic shock suspension, with wheels
acting as the primary point of contact between the suspension system and the terrain; allowing the
drivetrain and suspension system to bear the load of the rover. A space-frame chassis housed all major
electrical, controls, and communication components. The five-degree of freedom robotic arm acted as the
primary manipulator for a working environment, consisting of a lead screw, two supporting rods, four
aluminum limbs, aluminum links, and a 3D printed two finger adaptive gripper. The robotic arm leveraged
the SCARA and Polar art design to enhance the movement in vertical, X and Y motion, and rotation of the
arm. Challenges faced by the robotic arm during the testing phase in 2020 centered around dexterity,
mechanical limits and speed of the arm. The science life detection system was broken down into three main
components categories: science arm, soil distribution, science carousel, and fluidics. Odyssey utilized a
revolving chamber of hollow stem auger bits for the extraction of a solid core sample. During the 2019
URC, the hollow stem auger bits struggled to collect enough soil samples in the allotted time.
Figure 6: Odyssey’s Science Configuration
After completing the science field task, portions of the sample acquired were separated for the
biology and geology assays in which members of the team worked to identify samples of proteins or DNA.
The team identified the presence of bacteria and other microorganisms as well as studied their compositions
to demonstrate an understanding of the biochemical structures necessary to sustain life. Upon finishing their
analysis, the team presented its findings to URC field biologists. The electrical team designed custom PCB
breakout boards to improve wire management and serviceability within the chassis. Two kill switches were
used to act as emergency shut-offs for the primary power bank, motors, sensors, and the auxiliary power
bank, for the main computer; these power banks consisted of lithium polymer batteries, which allowed for
easily interchangeable power sources. The lithium polymer batteries were connected to voltage regulators
to supply proper power to each onboard system. All major electrical junctions consisted of discrete
connectors allowing for proficient serviceability during system maintenance. The rover’s on-board control
system was centered around Nvidia’s Jetson AGX Xavier, allowing for access to a high-performance GPU.
The rover received information from the base station via radio bands which are then interpreted by the
Xavier and relayed to each on-board system. For the autonomous task, the controls team leveraged a sensor
package to support real time obstacle detection and avoidance using a custom Simultaneous Localization
and Mapping (SLAM) model. The controls team learned to use Robotic Operating System (ROS) nodes to
coordinate sensor input into a visual interface and operating environment. A stereo camera unit mapped the
terrain with 3d point cloud data and depth sensing, it was the rover’s primary sensor for performing real
time obstacle detection and avoidance during the Autonomous Traversal Mission. Secondary sensors-
ultrasonic and 2D LiDAR-were used for redundancy if the camera were to fail. For identification of AR
tags, the controls team utilized an algorithm that could detect AR tags.
4.0 Technical Approach [Refer to Technical Volumes 1-4]
Robotics [Volume 01]: The robotic arm and end effector are a crucial part of the rover platform because
they are the centerpiece for all manipulation of objects in the rover’s immediate surroundings. The
robotics team is using MATLAB to create forward and inverse kinematic models for a robotic arm. As

11
designs progress, and parameters change, the models generated will be updated. Furthermore, ANSYS is
being utilized to perform FEA; simulating mechanical stress under expected loading conditions on the
robotic arm and end effector allows the team to verify the viability of design iterations. Using MATLAB
and ANSYS, the robotics team will be able to optimize their system through design iterations. The team
will need to assess the arm’s general performance against a standard benchmark, a mock equipment
servicing module, like the one seen at the URC was built to do this.
Figure 7: Timing Belt Assembly
Mobility [Volume 02]:Mobility focuses on the platform’s chassis, suspension, drivetrain
(motors/gearbox), and wheels/hubs. These are integral parts of the rover and ultimately, are responsible
for the movement of the entire platform. To comply with the URC size and weight restrictions, it is
essential to produce a lightweight chassis with versatile suspension that can withstand dynamic forces
from the robotic arm, science cache, and drivetrain assemblies. In addition, the chassis must adhere to
spatial constraints and must also consider efficiency in housing the suspension system, onboard
computers, and electrical/power components. Analysis of the mobility’s past competition performance
has proven that the current mobility system is robust and well designed. However, the wheel hub
assemblies are of complex geometry and are overengineered, making them too expensive to manufacture.
Figure 8: Suspension System
Chassis [Volume 03]: The chassis encompasses a few goals. The first of which it needs to satisfy is that it
houses and contains all the components of the rover. It must be able to protect and envelope all the
attachments the team hopes to include in our design. Secondly the chassis must be able to withstand all the
forces acting on different areas of the frame from external forces. When designing this frame we need to
take into account all the movements and obstacles the rover will encounter as well as the forces caused on
the frame by the weight of the rover itself and its components as they sway back and forth and complete
varying tasks. In order to do this we can call upon different areas of manufacturing, specifically the
automobile industry. The automobile industry has created a plethora of different designs of the chassis to
satisfy this dilemma. There however are three that stand out and formed the basis of our design
consideration for the chassis of the rover.
Figure 9: Layout of the Chassis
Science Cache [Volume 04]: System requirements include collecting top-layer soil at a depth greater
than 10 cm, distributing soil samples to sensors/microscopes and performing soil analysis. Mechanical
members of the science cache sub-team in collaboration with biologists and geologists, will design lab
experiments to be conducted onboard the rover platform. Furthermore, the science team shall minimize
cross contamination between soil sites. The core soil samples must be contained so it can be isolated from
the environment to prevent further contamination during transit to the lab base station. Once the soil has
been captured, a sensor probe will be deployed to gather data on the subsurface soil temperature,
volumetric water content and soil di-electricity.

12
Figure 10: Science system with Geneva gear system
5.0 Team Structure (WBS)
The Titan Rover mechanical team consists of 15 members from the senior design class. The team
is divided by four sub-teams: Mobility, Chassis/Manufacturing, Robotics, and Mechanical science. The
project lead and co-lead will divide half the workload to manage two teams. They are in charge of
keeping tracks of each sub-team’s progress and integration. Due to an overwhelming amount of interest
in the chassis team, we have decided to distribute members from the chassis team into each other sub-
teams. The purpose of that is to even out the workload, as well as providing each team with its own
manufacturing representative. Throughout the semester, we used various mediums to keep track of our
tasks such as Freedcamp, a task assignment website, as well as note taking during weekly meetings.
Figure 11: Mechanical team structure
Van Nguyen Project lead overseeing system design and systems integration; establishing and tracking
project deadlines in conjunction with both EGME 414 and the URC 2021 Guidelines.
Kristopher Kerames Project Co-lead responsible for maintaining overall mechanical system cohesion and
oversees the mechanical systems consisting of robotics and drivetrain sub-teams.

13
Mobility
Houston Tong Mobility subsystem lead overseeing the implementation of the drivetrain and suspension
systems, ensuring the mobility package performs optimally
Tony Nguyen Design engineer responsible for defining the requirements, selection, and design of the
suspension.
Juan Alvarado Design engineer co-responsible for defining suspension requirements and analysis of
drivetrain design.
Robotics
Sasha Licari Robotics subsystem lead responsible for implementing changes to the Odyssey arm which
will improve the performance of the robotic arm in the URC Mars rover competition. Designing a new
end effector that will improve function of the robotic arm.
Haley Choi Design engineer providing support for the robotics lead. Responsible for the base joint and its
mounting to the chassis.
Daniel Velasquez Design engineer responsible for the design of robotic limbs, joints, and motor
mounting. Redesigning the J4 joint to fit the functionality of the robotic arm and improve the movement
of the Odyssey robotic arm.
Lily Park Works closely with the robotics team to advise the best way the Odyssey arm will be
manufactured as well as performing stress analysis of the joints.
Chassis/Manufacturing
Axel Alvarez Loya Chassis lead responsible for overseeing the integration of all mechanical systems
aboard the rover. Additionally, the lead oversees spatial constraining of electrical and control system
components
Adrian Throckmorton Overseeing material research and establishing mounting solutions for mechanical
subsystems and the antenna mast.
Kevin Tran Responsible for performing stress analysis on all points of the chassis and performing hand
calculations to determine chassis life cycle.
Austyn Webster Ensure chassis CAD/CAM drawings are up to professional standards and can be
interpreted easily by other engineers and technicians.
Jonathan Tang Works closely with the mobility team to ensure components of drivetrain are
manufacturable as well as performing system analysis.
Science
Axel Alvarez Loya Science subsystem lead, responsible for overseeing the sensor array, on-site analysis
system, and coordination with lab scientists to deliver a life analysis science system.
Ajit Singh Works closely with the science team to ensure the use of proper materials suited for
prototyping and certain parts of the science assay.

14
5.0 Timeline
Titan Rover plans to adhere to a cumulative schedule and extends this to our respective electrical,
controls, and lab sciences teams to maintain cross-system progression. The proposed schedule is in
Appendix A. The critical timeline that Titan Rover plans to adhere to this year involves design reviews,
and freezes, to facilitate streamlined production. Upon release of URC 2021 Guidelines, Titan Rover will
establish its intent to compete in the following year in URC 2022. Following the critical design review
November 23, 2020, Titan Rover will undergo plans for a final, tentative design leading to the design freeze
December 15, 2020 in which all systems will be prepared for manufacturing as designed. Additionally,
Titan Rover will be required to submit a PDR to senior design class, demonstrating progress with the
system and clarifying the team’s current progress. The only system changes permissible beyond this
window will be for minor components due to complication or failure during testing. Titan Rover plans to
begin manufacturing over the university intersession following the new-year only if permissible by the ME
department; tentatively outsourcing manufacturing until completing the primary framework of the platform
by February 2022. At this time, the team will begin preparations for URC’s final review, SAR, which will
narrow the pool of original applicants to permitted competitors in May 2022. The final platform is
scheduled to be completed no later than March 1, 2022, allowing for approximately 3 months of fully
integrated testing, leading to the URC in June 2022.
Figure 12: Competition year schedule
6.0 Statement of work
The URC 2021 guidelines constraints Titan Rover’s electromechanical design, controls system,
and science cache. While this does not fully define the structure of the system, it establishes a limit, to
include system constraints, budget limitations, review documentation and communication protocols. Our
biggest constraint is time and in order to perform well at competition, the team needed to plan before the
start of the school year. This phase consists of member recruitment, background research, and schedule
planning. Once we have the team and roles established, we move forward with planning for the competition
more in depth. The next phase is the project proposal, where we reanalyze the current functionality of the
rover to look for points of improvements and redesign. Through that, we could then figure out the schedule,
budgeting, as well as diving tasks among team members. Our next phase is conceptual design, where our
ideas come to fruition, through calculations and mock up CAD designs to ensure concepts are feasible.
During this process, we dealt with a lot of trial and error, as well as trying out different designs. Our final
phase for this semester is the Preliminary Design Review. During this phase, we were still making iterations

15
of different designs and keeping integration in mind as teams develop prototypes. After finalizing our
design decisions, we verified our design once again through various approaches to determine evidence of
baseline feasability. Through this, we make sure that weight cuts are performed, as well as choosing the
right materials for different types of purposes. During the competition year, a PDR document is required
from each competing team to be submitted to PDR. The purpose of this is so verify that each team will be
ready for competing on time based on our design plans as well as manufacturing. We make sure once again
that our ideas are feasible by presenting to our classmates, as well as alumni and faculty. After receiving
said feedback, we will go through correction and eventually fabrication in the spring. The manufacturing
phase will last two months before we put the system together to prepare for competition.
7.0 Budget
Titan Rover anticipates a total platform expenditure this year of $25,929.00 which has been reduced, through a
cost-benefit analysis, from an initial estimate of $40,584.00. This amount has been tailored to reflect the cost of only
the necessary components for developing a competitive rover. These components include on-board systems and
laboratory analysis tools, as shown in the itemized expenditures table in Appendix B. The costs associated with
attending the URC are not included, as the Titan Rover’s eligibility for competing is contingent upon approval of the
SAS. The total amount has been adjusted to account for cost savings due to current sponsorships by Altium and
Misumi. Other options for obtaining funding through online fundraising are also being considered, as many traditional,
in-person fundraising efforts are not possible in the context of COVID-19.
Spring 2021, the team ended up not buying many things for the team. The only budget spent was for electrical
and controls team, as well as robotic kits for next year’s team to use.

16
8.0 ABET requirements
ABET requirements were fulfilled by considering specific realistic constraints throughout the system
development life cycle. An overview of how constraints were, or will be, addressed is provided below
(Specific examples and pages in which they are mentioned are provided in table 2 at the end of this
report).
Economic
Economic constraints were addressed by minimizing the budget through a cost-benefit analysis of
potential designs. The useful life of each system was maximized through careful design that considers
durability and minimizes maintenance costs.
Environmental
Environmental constraints will be addressed by recycling all batteries at the end of their useful life.
Sustainability
Materials used in the Titan Rover project can be sourced and recycled sustainably. Many of the materials
from past iterations of the rover have already been factored into the new design.
Manufacturability
Manufacturability was addressed by designing systems to accommodate a variety of manufacturing skill
sets within the team. Multiple manufacturing methods were considered within each sub-team in order to
find the optimal method for each part.
This is especially true for the mobility sub-team where drivetrain component designs from previous years
had been difficult to manufacture.
Ethical
When it comes to ethical issues, the Titan Rover team has operated under standard codes of ethics, such
as those of IEEE and NSPE. Ethics did not have to be addressed directly because the rover inherently falls
within the ethical framework outlined by these organizations; The designing, building, and operation of
the rover does not violate any of these codes of ethics.
Social
The Titan Rover project allows students to contribute ideas to the field of space exploration, which
provides society with many opportunities in the form of resources, new technologies, and advancement in
scientific knowledge. We addressed these issues by planning outreach events to educate the community.

17
Health and Safety
In the development of the rover, safety of the team members is paramount. In-person contact related to
the project was prohibited within our team during the COVID-19 outbreak to mitigate the spread of the
virus. Additionally, the rover will be operated under the guidance of alumni with experience controlling it
to avoid potentially dangerous mistakes that have been made when operating it in the past.
Political
The final issue that was addressed is political constraints. Some government funding was allocated to this
project and will be used in the best interest of public entities, like California State University Fullerton.
This project also furthers the field of space exploration, which is advantageous in a political context.

18
Table 2
Pages Where ABET Requirements Are Addressed or Considered
Constraint Volume/Page Summary
Economic Systems Overview, pages
16–18;
Volume 01, page 33;
Volume 02, page 7 & 37;
Volume 04, page 4, 21, & 26;
Volume 03, page 19 & 26
Addressed on page 16-17 of
the Systems Overview which
contains a taylored budget
that reflects how costs were
minimized without
compromising on design
quality. Page 18 elaborates
on this. Page 26 of volume 01
covers cost savings that are
specific to the robotics sub-
team. The literature survey
beginning on page 7 of
volume 02 explores the most
economic options for
drivetrain components. Page
4 of volume 04 mentions how
the amount of material used
in the science sub-system
was minimized in order to
reduce overall cost. Volume
03, page 19 & 26 covers
economic constraints specific
to the chassis.
Sustainability Systems Overview, page 18;
Volume 01, page 33;
Addressed in the pages
mentioned. Page 18 of the
Systems Overview elaborates
on sustainability stating how
any parts that can be reused
will be reused. Page 26 of
volume 01 goes over how the
robotics team plans to recycle
and reuse materials from the
robotic arm. Page 20 of
volume 02 accounts for the

19
most sustainable options in
analyzing the mobility sub-
system.
Environmental Systems Overview, page 18;
Volume 01, page 33;
Volume 02, page 37
on environmental concerns
stating that batteries will be
recycled. Page 26 of volume
01 goes over how simulations
of the robotic arm can reduce
the amount of prototypic
required, and prevent
possible pollution from
unnecessarily building parts.
Manufacturability Systems Overview, page 18;
Volume 02, page 5, 7, & 37;
Volume 01, page 33;
Addressed in volume 02,
page 5, where
manufacturability is factored
into designs. Additionally,
page 7 of volume 02 reviews
literature to identify optimal
manufacturing methods for
the mobility s Page 17 of the
Systems Overview and page
26 of volume 01 elaborates
on manufacturability. Volume
04 covers manufacturability
of the mechanical science
sub-system and how 3D
printing was chosen to be an
optimal method for many
parts. Volume 03, page 19 &
14 covers manufacturing
methods specific to the
chassis.
Ethical Systems Overview page, 18;
Volume 04, page 21;
Volume 03, page 19
Considered in the pages
on ethical concerns stating
that IEEE and NSPE ethical
guidelines were adhered to.
Social Systems Overview, page 18;
Volume 01, page 33;
Volume 02, page 37
Volume 04, page 21;
on social constraints of the

20
Volume 03, page 19 project stating that the rover
contributes to society by
furthering space-exploration-
related technologies and
educating students. Page 26
of volume 01 covers how
showcasing the rover to the
public will help educate
students and other members
of the public.
Health & Safety Systems Overview, page 18;
Volume 01, page 33;
Volume 02, page 37–38;
Volume 04, page 21;
Volume 03, page 19
on health and safety by going
over how the Titan Rover
team navigated the
landscape of the COVID-19
pandemic safely while
designing the rover. Page 26
of volume 01 goes over the
kill switch on the robotic arm
designed to uphold safety
standards in case anything
goes wrong when operating
it.
Political Systems Overview, page 19 Addressed in the pages
on political constraints by
reviewing this project’s
appeal to public entities.

21
References
[1] “University Rover Challenge 2021 – Requirements and Guidelines.” University Rover
Challenge, The Mars Society, 20 Sept. 2020,
http://urc.marssociety.org/files/University%20Rover%20Challenge%20Rules%202021.pdf

Titan Rover: Robotics Sub-team
Technical Volume 01
California State University of Fullerton
Team Members
Sasha Licari
Daniel Velazquez
Haley Choi
Lily Park
EGME 419 Senior Design 2
May , 2021
1

Table of Content
List of Figures 3
List of Tables 4
Abstract 5
Purpose 6
Project background 7
Project Objectives and Requirements 12
Technical Approach 13
Proposed Design Solutions 14
Conceptual design 15
Detailed design 16
Drawings 20
Budget 23
Project Management 24
Robotics 24
Discussion 25
ABET Requirement 26
Appendix 27
2

List of Figures
Figure 1: End effectors ............................................................................................................. 10
Figure 2: Belt systems .............................................................................................................. 10
Figure 3: Roller Chain ............................................................................................................... 10
Figure 4: Timing Belt Assembly.................................................................................................. 16
Figure 5: Roller Chain Assembly …........................................................................................... 16
Figure 6: RAG+Housing assembly............................................................................................. 16
Figure 7: Pneumatic Gripper Model............................................................................................ 18
Figure 8: FEA Stress Analysis on Pneumatic Grippers.............................................................. 19
Figure 9: Servo Electric gripper.................................................................................................. 20
Figure 10: FEA Stress Analysis on Pneumatic Grippers............................................................ 21
Figure 11: Roller Chain System ................................................................................................. 21
Figure 12: Roller Chain Force vs Working Load. ....................................................................... 22
Figure 13: Roller Chain Weight and Length Variations .............................................................. 23
Figure 14: The Robotic Arm divided into subsections................................................................ 24
Figure 15: Pneumatic Gripper Model......................................................................................... 25
Figure 16: Servo Electric gripper................................................................................................ 26
Figure 17: ANSI 35 Roller Chain Drawing.................................................................................. 27
Figure 18: ANSI 35 12 Teeth Sprocket Drawing......................................................................... 28
Figure 19: ANSI 35 24 Teeth Sprocket Drawing......................................................................... 29
3

List of Tables
Table 1:Trade Study between RAG vs Roller Chain vs Timing Belt ...........................................15
Table 2:Budget…………………………........................................................................................30
4

Abstract
The robotic Arm and the end effector are a crucial part of the Titan Rover platform
because it is the centerpiece for all manipulation of objects in the tover’s immediate
surroundings. By Utilizing the design of the robotic arm from 2018-2019 design, improvements
will be made to advance its usability by adding a roller chain system and dexterity by
redesigning the grippers. THrough design modifications the new 2020-2021 arm will be a
modified and improved version of the arm from 208-2019. While the majority of the arm will not
change in design due to covid 19, a new prototype of the grippers will be 3D printed and tested
for durability. The URC rules and guidelines will be followed for this year, but the rover will not
compete in the competition due to restrictions for Covid 19.
5

Purpose
Changes to this platform aim to address specific problems which were encountered in
the 2018-2019 version. Due to covid 19 the gripper and the belt system were chosen as
problem areas because they were easier to research in a virtual environment.
These changes are most significant in the areas of arm serviceability. In addition to this
the URC requirements between 2018-2019 and 2020-2021 have not changed, thus
requirements for the end effector stay the same. The changes to the end effector are to
redesign it completely and test it. Another change to the gripper that can be implemented is to
use the same gripper design from 2018-2019 year and change the material to make it durable.
Material for the end effector such as polyurethane, rubber for end effector finger tips, aluminum,
stainless steel can be tested for durability and efficiency.
6

Project background
There are multiple types of end effector technologies all with pros and cons. The
grippers are typically defined by four different parameters which include impactive (jaws or
claws), ingressive (pins and needles), astrictive (vacuum, magneto- or electroadhesion), and
cognitive (such as glue, surface tension or freezing).
Figure 1: Types of end effector configurations.
There are multiple types of belt systems all with pros and cons. Belt systems are
typically defined by flat belt, classic v belt, wedged belt, cogged v belt, and roller chain belt.
7

Figure 2: Types of belt systems not including roller chain belt.
8

Figure 3: Roller chain for the roller chain belt system.
The new design consists of a different belt system and different end effector. The belt
system is a chain roller system that provides a high efficiency non-slip driving medium. It does
the while minimizing loads on the drive motor and driven shaft since no pre-load is required to
tension the chain in the static condition. The new design for the end effector is between
pneumatic grippers and servo electric grippers. These designs need to be prototyped and tested
before finalized design is chosen.
The rest of the arm will stay the same from the 2018-2019 year model and will consist of
an articulated robotic arm. Some of the key advantages of not redesigning the arm are it is
9

easier to align to multiple planes, simple to operate and maintain, has a large working envelope
compared to its footprint, and can reach any point in the work envelope. Going with the same
arm design as from the 2018-2019 year is done because of the advantages listed above, and
because the specific design in prior usage could accomplish all tasks needed for URC
competition. In addition, due to restrictions from Covid-19 we were limited on what we could do
to the arm in a virtual environment. The robotic arm had less problematic areas thus allowing us
to perform research and development on the end effector and belt system.
The following drive systems remain the same on the arm from the year 2018-2019.
There are two types of drive systems used on the arm design, linear actuators and DC stepper
motors. Linear actuators are used to driveJoint 2 (J2) andJoint 3 (J3) while DC stepper motors
are used to driveJoint 1 (J1), Joint 4 (J4), and Joint 5 (J5.1 and J5.2) 3 with many of them using
a gearbox to achieve higher torque values. The main advantages of using linear actuators are
● They have a simpler and lighter design compared to pneumatic or hydraulic
actuators.
● Electrical actuators provide a finer level of control throughout the entire motion
process
● Integrated servo motor and roller screw actuator solutions with feedback,
connectors, and wiring configured for a true “plug and play”4
experience.
While dome of the benefits of DC Stepper motors are (Advantages & Disadvantages of
Stepper motors & DC servo motors):
● Stable and can drive a wide range of frictional and inertial loads
● Inexpensive relative to other motion control systems.
● Standardized frame size.
● Easy to set up and use.
● If anything breaks, the motor stops.
● Excellent low speed torque, can drive many loads without gearing.
● Excellent repeatability, returns to the same location accurately.
● Overload safe, motor cannot be damaged by mechanical overload.
While the use of actuators and electrical wiring through the arm limits the movement,
there is a limited work envelope[1] which is needed to complete the tasks the arm is designed
for. This limited work envelope allows for the use of such drive systems, joints, and
connections. Each joint needs a limited movement to achieve a work space which can enable
us to complete the URC’s tasks. The system must be able to go below grade (reach the
ground), must not collide with the chassis or itself, and be able to reach up to 5ft from ground
level (Equipment Servicing Task Questions). The movement constraints that are being used
are as follows[2]:
Joint 1: 220° (antennas to the rear of the rover prevent a full 360, while cabling limitations also
prevents a 360° infinity rotation)
Joint 2: 90° (-15-75 where negative degree marking indicates its position below horizontal)
Joint 3: 90°
10

Joint 4: 110°
Joint 5.1: 360° infinity
Power for these drives will be provided by a 24V DC power line. This allows many of the
electrical components of the Rover to use the same power source.
Other Constraints
Payload: 15lb at the end of J5
System Weight: 30lb
Reach: 5ft from ground level
11

Project Objectives and Requirements
Given the weight, financial constraints of the mechanical team and Covid-19 pandemic,
the robotic arm must weigh less than 30lbs, cost no more than $4,179 to construct the arm, and
must be researched in a virtual environment. The robotic arm must follow the URC
requirements. There are two stages of task that need to be performed first is extreme delivery
and retrieval, and second is equipment servicing. The extreme delivery and retrieval tasks
include: System must be capable of performing pick and place tasks within 1 km range in a time
frame of 30 to 60 minutes. These objects will be graspable and will have dimensions of 40cm x
40cm x 40cm. These objects include hand tools: hammer, wrenches, supply containers:
toolboxes, gasoline cans, water bottles. The arm must be able to pick up a payload of 5kg, and
must be capable of pulling an object by a rope. The equipment servicing tasks include being
capable of performing dexterous tasks such as opening drawers, inserting a USB memory stick,
controlling joystick to move an antenna while observing a gauge, flip switches and push buttons.
The arm must be able to input commands on a keyboard, screw and unscrew objects, and pick
up and transport a cache weighing no more than 3kg.
12

Technical Approach
Major components which will remain the same or largely unchanged are:
● Motor and Gearbox (10:1) for J1.
● Motor and Gearbox for J4.
● Carbon Fiber sections
● Titanium pins used to joint J1-J2, J2-J3.
● “E” clip holding method for all pins
● General Design of the J2 dual actuator mount.
● J2 actuator (adding manufactured integrated feedback)
● J3 actuator (adding manufactured integrated feedback)
● [Proposed] Removal of V1 joint which bisects the current J3
● J5 gripper tips (to add dexterity)
● “Wristwatch” linkages hold all structural carbon fiber.
○ One version for limbs with no planned servicing access.
○ One version for limbs which will see frequent servicing.
● J3 female broken into separate parts for ease of machining/weight cutting.
● J4 Male and Female Joint for weight cut/ ease of machining. Cover plate will be added.
● J2 Male redesign for weight cut/ ease of machining. Cover plate will be added at J3
intersection.
● J2 dual actuator mount redesign for weight cut.
● J1 female mount redesign for weight cut/ ease of machining[1]. (including welding and
machining combination)
● Addition of panel mount connectors and coiled spring cable to externally bridge a
connection from J4 to J5.
Note: That the end effector is still under analysis at the time of writing this report
Major components/subsystems which will change.
● The end effector
● The belt system. (roller chain will be implemented)
13

Proposed Design Solutions
The robotic arm from the year 2018-2019 will be chosen due to covid-19 restrictions. It
has less issues that can be done virtually than other robotic arms. The areas of interest are the
end effector and the belt system. All research and development will be done virtually due to the
pandemic and quarantine.
The robotic arm will undergo redesign of the end effector and the belt system, the rest of
the arm will remain the same. The end effector will be completely redesigned, and the belt
system will be semi redesigned. The end effector will either be a pneumatic gripper or servo
electric gripper. The existing parallel gripper could be redesigned by changing the material used
to make it more durable and be able to withstand 150 ℉ heat in the Utah desert. The redesigned
roller chain belt system will increase performance of the arm by providing the required torque at
J4 to lift the 15 lbs payload and have no slippage. Robotics will seek to use durable 3D printable
material such as delrin. Due to Covid -19 these proposed designs have only been theoretical,
because all the research and development thus far has been done virtually.
14

Conceptual design
The robotic arm will undergo changes for the end effector and belt system. The end
effector was narrowed to three proposed solutions, two of the solutions have to redesign the end
effector completely and the third is to use existing end effector and change the material. The two
end effectors for complete redesign were chosen based on their usability, lightweight and
serviceability. One option is Pneumatic grippers, they are lightweight, compact size, and
usability for URC tasks. Second option is Servo-electric grippers, they are easy to control, highly
flexible and cost effective. These two options were modeled in solidworks and Finite Element
Analysis(FEA) was performed on them. The third option is to use the existing parallel grippers
and change the material they are made of to a more durable material. The material we are
considering for the parallel grippers is delrin, because it's lightweight and cost and weight
effective. Due to restrictions of the pandemic and lack of technology capable of handling big files
we were not able to perform FEA on the parallel grippers. We can not decide on the finalized
design until we have prototypes of all three options for end effectors.
To resolve the belt system slippage and lack of tension in the prior robotic arm an
improved design is necessary. The roller chain system was chosen over the two alternatives
due primarily for its performance benefits. The roller chain system will provide the required
torque at j4 and will not have slippage. This design has a big downside of potentially adding too
much weight to our system which could be detrimental even with the increased
performance.The torque and force on the roller chain was calculated, the model was created in
solidworks. Based on the calculations the prototyping phase is next on the agenda.
Table 1: Trade Study between RAG vs Roller Chain vs Timing Belt
Criteria Weigh
ts
Timing belt driven
system
Roller chain driven
system
RAG+ Housing
Cost 2 S S -
Performance 4 - + +
Machinability 1 S S -
Weight 3 + - -
Sum of
positives
1 1 1
15

Sum of
negatives
1 1 3
Overall total 0 0 -3
Weighted total -1 1 -2
Figure 4: Timing Belt Assembly
Figure 5: Roller Chain Assembly
Figure 6: RAG+Housing assembly
16

These two systems for redesign were chosen because they are easier to research in a
virtual environment. Now the prototypes need to be made in order to finalize which design will
best fit the robotic arm.
17

Detailed design
These are the models and criterias for the redesign of the end effector and belt system.
Figure 7: Pneumatic Gripper Model.
Pneumatic gripper is lightweight and can easily fit into small and tight spaces. That is
needed to type on the keyboard for URC.
18

Figure 8: FEA Stress Analysis on Pneumatic Grippers.
We can see deformation happening at the base of the fingertips and the base of the
finger. That is taken into account when comparing the two designs of the different grippers. The
yield strength is 6.208e+08.
19

Figure 9: Servo Electric Grippers
The servo electric grippers are easy to control and are highly flexible, they allow for more
material tolerancing and cost effective.
20

Figure 10: FEA Stress Analysis on the Servo Electric grippers
The biggest area of deformation is where the finger basse meets a rod in the gripper
base. The yield strength is 6.204 e+08 (N/m^2)
Figure 11: Roller Chain Belt System.
21

In designing the Roller chain belt system there are some factors that must be decided
before choosing the type of chain and sprocket to use. Using the current weights implemented
into the system the minimum required torque at joint 4 to lift the gripper assembly of 3.5 lbs and
a payload of 15 lbs was calculated to be 249 lb-in. This leads to a selection of a NEma
17+100:1 gearbox a 2:1 pulley ratio was chosen and provides a max holding torque of 775 lb-in.
A benefit of keeping the motor and gearbox is reduced system implementation which is
necessary to consider with our shortened manufacturing window due to covid.
After finding the max holding torque of the chain is selected on the basis of its working
load and weight. Since joint 4 needed to be able to withstand a tensile force due to the max
holding torque the chain experienced a tensile force of 455 lbf. This results in a high strength
ANSI 35 chain was chosen as it is the lightest choice available and had a working load of
560lbf.
Figure 12: Roller Chain Force vs Working Load
To ensure that the chain and sprockets mate properly and prevent skipping there are a
few conditions that have to be met.
1. An ANSI 35 sprocket must be chosen to have the gap between the teeth be large
enough for the roller diameter of .1875”. This ensure that the roller will properly rest at
the bottom of the teeth eliminating the chance of the chain skipping if there is no wear on
the teeth present
2. Ensure that the correct chain length is selected given the center distance and the
number of teeth on both the driven and driver sprocket. With a venter distance of 12.20
inches from the current system we get the lengths in Figure 13 for a few different teeth
amounts. At the smallest configuration we get a length of 31.19”. This configuration also
has a weight of .545lb.
22

Figure 13: Roller Chain Weight and Length Variations
Prototypes of these three lengths will be assembled to validate that the proposed design
can provide that torque to lift the maximum payload of 15 lbs. This will also be done to observe
the physical characteristics of the system such as cordial action which are vibration in the
system due to the chain's movement. This is due to the increase of vibrations as the number of
teeth decrease so physical prototyping is required.
23

Drawings
Figure 14: The Robotic arm divided into subsections.
24

Figure 15: Pneumatic Gripper Model.
25

Figure 16: Servo Electric Gripper Model.
26

Figure 17: ANSI 35 Roller Chain Drawing
27

Figure 18: ANSI 35 12 Teeth Sprocket Drawing
28

Figure 19: ANSI 35 24 Teeth Sprocket
29

Budget
This is a summary of the budget for the mechanical Robotics team.
Table 2: Budget Report.
Items Pricing Quantity Notes
force sensors $70
force sensor kits $350
1kg spool $30
testing different spool $150
silicone rubber coating $35
belt for J4 $53.40 3
need to buy multiple and try out different
types of belts
linear actuator for J5
material to replace
carbon fiber $2-$20 fiberglass/ need to look into other materials
3-Finger gripper from
ROBOTIQ $600
3D printed 3-Finger
gripper $400
Spur gear for gripper
assembly $47.34 3
ring gear for grippers
$57.74-$1
29.30 $130
Aluminum plate $27-$162 Depends on how much material we need $162
100:1 Nema 23 Gearbox $74.44
30

Project Management
Robotics
Sasha Licari Robotics subsystem lead responsible for implementing changes to the Odyssey
arm which will improve the performance of the robotic arm in the URC Mars rover competition.
Designing a new end effector that will improve function of the robotic arm.
Haley Choi Design engineer providing support for the robotics lead. Responsible for the end
effector, base joint and its mounting to the chassis.
Daniel Velazquez Design engineer responsible for the design of robotic limbs, joints, and motor
mounting. Redesigning the J4 joint to fit the functionality of the robotic arm and improve the
movement of the Odyssey robotic arm.
Lily Park Performing stress analysis on the end effector, working closely with the manufacturing
subteam to ensure everything is manufactured properly.
The project was divided into smaller tasks. Each member showed an interest in one of
the two areas of interest: the end effector and belt system. After each member chose what they
wanted to work on, those tasks were assigned to them in freedcamp. Every week we had a
meeting to update each other on our progress and to inform the other sub teams of what we
have done. We modeled components in solidworks and performed stress analysis on the
models. The tasks started out with researching the topics they chose and then they had to
collect the information they learned in a document. They had to compare different types of end
effectors and different belt systems to make sure that they had a good performance criteria.
After that they had to narrow down their results using morphological charts and pugh charts to
help decide on what design is a better fit. Once that was done they had to model their designs in
solid works and perform stress analysis on the models they designed. In some cases they had
to do hand calculations for their designs.
31

Discussion
Prototyping and manufacturing is a big concern because of Covid-19, we still do not
know if we will have access to the rover in the spring semester. It will depend if we will have
access to the machine shop on campus, or outsource everything to industry professionals. If we
outsource manufacturing we have to be aware of the budget and its limitations. With this in mind
we have tried designing certain components with minimal interface changes with the existing
system to reduce the required manufacturing .
While mentioned throughout the report serviceability is a key factor in design iterations of
the robotic arm. The aesthetics of the arm are also important since we want to attract sponsors,
employers, the general public and student interest at CSUF.
Cross department communication is implemented to aid in a smooth transition of
components. With the Science team, mechanical integration of a science payload to be able to
fit on the end of the arm. And the electrical team has been close at hand when deciding
feedback modules and connectors.
Many design choices and rejections were made because of the lack of access to the
rover and lack of work space. We are keeping the design of the 2018-2019 arm because of the
restrictions due to Covid-19. We had to implement iterative changes to the arm because of the
lack of resources and lack of workspace.
Given all the restrictions, we conducted research on different types of grippers and belt
systems to insure that we are making the correct design choices. Once we finish prototyping we
can finalize our design and start the manufacturing phase.
32

ABET Requirement
Economic
The grippers and the belt system can be produced within realistic cost constraints. Thus
meeting the Economic requirement.
Environmental
The environmental requirement is utilized since we are reusing an arm from previous year and
doing incremental changes to it. We also do a lot of testing before prototyping many parts which
prevents pollution.
Sustainability
When the useful life of a product expires we can recycle its parts. The 3D printing materials
could be recycled and more companies are learning how to recycle it. The metals can be
recycled also.Sustainability was considered by conserving the design of the arm and the
systems we are redesigning.
Manufacturability
The manufacturability of the components can be manufactured using standard manufacturing
processes.
Social
Showing the rover to the public will help teach people about science and engineering. Doing
outreach events helps spread the information about different STEM fields. Which will help
people have an interest in science and engineering. Thus providing future scientists and
engineers that can improve the quality of people's lives.
Health and Safety
Health and safety requirements are considered to make sure everyone is safe around the rover
and the robotic arm. The rover has a kill switch that can stop any movement of the arm thus
creating a safe working environment and preventing injuries from happening.
33

Appendix
Four different parameters which define an end effector
Impactive grippers- Uses jaws or claws that can grasp objects.
Ingressive - Uses pins and needles that penetrate through objects to pick them up.
Astrictive - Uses vacuum, magneto- or electroadhesion to pick up objects.
Cognitive - Uses glue, surface tension, adhesion, and freezing to pick up objects.
Number of Axes – Two axes are needed to reach any point in a plane. Three are required to
reach a point in space. Roll, pitch, and yaw control are required for full control of the end
manipulator.
Degrees of Freedom – Number of points a robot can be directionally controlled around. A
human arm has seven degrees; articulated arms typically have up to 6.
Working Envelope – Region of space a robot can encompass.
Working Space – The region in space a robot can fully interact with.
Kinematics – Arrangement and types of joints (Cartesian, Cylindrical, Spherical, SCARA,
Articulated, Parallel)
Payload – Amount that can be lifted and carried
Speed – May be defined by individual or total angular or linear movement speed
Acceleration – Limits maximum speed over short distances. Acceleration is given in terms of
each degree of freedom or by axis.
Accuracy – Given as a best case with modifiers based upon movement speed and position
from optimal within the envelope.
Repeatability – More closely related to precision than accuracy. Robots with a low repeatability
factor and high accuracy often need only to be recalibrated.
Motion Control – For certain applications, arms may only need to move to certain points in the
working space. They may also need to interact with all possible points.
Power Source – Electric motors or hydraulics are typically used, though new methods are
emerging and being tested.
Drive – Motors may be hooked directly to segments for direct drive. They may also be attached
via gears or in a harmonic drive system
Compliance – Measure of the distance or angle a robot joint will move under a force.
34

References
Advantages & Disadvantages of Stepper motors & DC servo motors. 2010.
<http://www.machinetoolhelp.com/Automation/systemdesign/stepper_dcservo.html>.
Roller Chain Installation
<https://www.ibtinc.com/roller-chain-installation-guide/>
High Efficiency Belt Drives
<http://www.iipinetwork.org/wp-content/Ietd/content/high-efficiency-belt-drives.html>
URC Team Information 2020-2021
<http://urc.marssociety.org/home/team-info/preliminary-design-review>
URC Requirements 2020-2021
<http://urc.marssociety.org/home/requirements-guidelines>
Design Manual Timing Belts
<https://www.mitsuboshi.com/english/product/catalog/pdf/V832-E_timingbelt.pdf>
“Handbook of Timing Belts, Pulleys, Chains and Sprockets”,
<http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf.>
Tsubaki, The Complete Guide to Chain
<http://tsubaki.ca/pdf/library/the_Complete_guide_to_chain.pdf>
Budynas, R. G., Nisbett, J. K., & Shigley, J. E. (2020). Shigley's mechanical engineering design.
New York, NY: McGraw-Hill Education.
Power Rating for Single Strand Roller Chain
<https://mpta.org/wp-content/uploads/2016/05/Power-Ratings-122001R1.pdf>
Roller Chain Calculation Basics
<https://knowledge.autodesk.com/support/inventor/learn-explore/caas/CloudHelp/cloudhelp/201
6/ENU/Inventor-Help/files/GUID-F7B55633-DDE2-4740-A642-8E2099E3A031-htm.html>
35

Titan Rover: Mobility Sub-team
Technical Volume 02
FINAL REPORT
California State University of Fullerton
Team Members
Houston Tong
Tony Nguyen
Juan Alvarado
Jonathan Tang
EGME 414 Senior Design

Table of Content
1.0 List of Figures…………………………………………………………………………………….……3
2.0 List of Tables………………………………………………………………………………………..….4
3.0 Abstract…………………………………………………………………………………………....…...6
3.1 Project Objectives…………………………………………………...……………………………......7
4.0 Project background…………………………………………………………………………….……...7
4.1 Project History………………………………………………………………………………...……...8
4.2 Literature Survey……………………………………………………………………………....……...9
5.0 Proposed Conceptual Design .………………………………….…………………………………...13
5.1 Components of System……………………..……………..………………………………………...14
5.1.1 [Motor and Gearbox]........................................................................................................................15
5.1.2 [Tire and Wheel Hub]...................................................................................................................16
5.1.3 [Shock Absorber]........................................................................................................................ 18
5.1.4 [Dual Wishbone Suspension]...................................................................................................... 19
5.2 Requirements, specifications, projections………………………………..…………………………..21
5.2.1 Drivetrain…………...………………………………………………………….…………..............21
5.2.2 Suspension……….…………………………………………………………….…………..............23
5.3 Analysis………………….……………………………………………....……………...………….25
5.3.1 Motors………………….……………………………………………....……………...………….25
5.3.2 Wheel Hub and Tires………………………………………………....……………...………….28
5.3.3 Shock..………………….……………………………………………....……………...………….31
5.3.4 Control arm…………….……………………………………………....……………...………….34
6.0 Prototype Testing and Results (Simulation Results) *NEW ADDITION………….……………40
6.1 Design Space Refinement……………………..……………..……………………....…………..…...40
6.1.1 Physical Modeling Assumptions......................................................................................................41
6.2 Design Space Refinement……………………..……………..……………………….…..……...…...45
6.2.1 Utilization of FEA…………….......................................................................................................46
6.2.2 Utilization of CAD………...….......................................................................................................64
7.0 Prototype Model and Fabrication Planning………………………………….……………….……68
7.0.1 System Summary …....….…………..………………………………….………………………….68
7.0.2 Tire and Wheels …....….…………..………………………………….………………………..….69
2

7.0.3 Shock Absorber... …....….…………..………………………………….………………………….72
7.0.4Dual Wishbone Suspension ……………………..…………………….………………………….74
8.0 Project Summary and Future Implementation………….………………………………………....75
8.0.1 Summary..…………………...………………………………………………………………….….75
8.0.2 Future Implementation……...………………………………………………………………….….77
9.0 Sub-team structure and Tasks………………………………………………………………....……80
10.0 ABET Requirement………………………………………………………………………………...83
11.0 References…….……….....……..…………………………………………………..….....……….. 85
12.0 Appendices………………………………………………….……………………………...………..86
12.1 Morphological Charts ……………………………………................................................................86
12.2 Detailed Calculations …………………………………….................................................................87
12.3 Component List and Estimated Mass………………………………………..………...…………....94
12.3 Budget……………………………………………….………………………….…...…………....94
3

1.0 List of Figures
Figure A1: [BLDC Rotor Diagram].............................................................................................. 9
Figure A2: [Geared Hub Drive]
....................................................................................................10
Figure A3: [Airless Tire Patent (Mun, Kim, Choi)]
........................................................................11
Figure A4: [Michelin Tweel] ........................................................................................................12
Figure A5: [Airless Tire Mathew, Sahoo, Chakravarth] ...............................................................12
Figure B1: [Block Diagram] ........................................................................................................14
Figure B2:[Mobility System excl. Wheels ] .................................................................................14
Figure B3:[Solidwork Model of Drivetrain ] .................................................................................15
Figure B4:[Wheel Hub Assembly (Odyssey)] ............................................................................16
Figure B5:[Airless Tire Concept Design ] ...................................................................................16
Figure B6:[Shocks Mounted On-board Chassis ] ......................................................................18
Figure B7:[Dual wishbone assembly ] .......................................................................................19
Figure 1.1: [Force diagram for motors]
.........................................................................................25
Figure 1.2: [Torque Requirement Graph]
......................................................................................26
Figure 1.3: [Diagram Gear Ratio In/Out]
.......................................................................................27
Figure 1.4: [Diagram of 6 Spoke Force
Analysis]..........................................................................28
Figure 1.5: [6 Spoke
FEA]..............................................................................................................29
Figure 1.6: [Honeycomb Spoke
FEA]............................................................................................30
Figure 1.7: [DNM Bike Shock A0-42
AR].......................................................................................31
Figure 1.8: [DNM Bike Shock
A0-42RC]........................................................................................32
Figure 1.9: [KindShock A5
RR-1]...................................................................................................33
Figure 1.10: [Odyssey Suspension Diagram-
Neutral]..................................................................34
Figure 1.11: [Odyssey Suspension Diagram -
Max]......................................................................35
Figure 1.12: [Odyssey Suspension Diagram -
Min]......................................................................36
Figure 1.13: [Static Stress FEA lower Control Arm Odyssey].....................................................37
Figure 1.14: [Lower Control Arm FEA Vertical Loading Odyssey]...............................................38
Figure 2.1: [Wheel Assembly Loading Force
Model].....................................................................42
Figure 2.2: [Wheel Assembly Torque Loading
Model]]..................................................................42
Figure 2.3: [Lower Control Arm Force
Model]................................................................................44
Figure 2.4: [Lower Control Arm Vertical Loading
Model]...............................................................45
4

Figure 2.5: [Simplified Mesh for
Tires]...........................................................................................46
Figure 2.6: [Applied Loading Tire,
ANSYS]....................................................................................46
Figure 2.7: [Tire Stress
Gradient]..................................................................................................48
Figure 2.8: [Tire Factor of Safety Gradient
]..................................................................................48
Figure 2.9: [Tire Torque and Weight Loading].............................................................................49
Figure 2.10:[Tire Torque Stress
Gradient].....................................................................................50
Figure 2.11: [Tire Torque Deformation
Gradient]...........................................................................51
Figure 2.12: [Wheel Assem.
Mesh]]..............................................................................................52
Figure 2.13: [Applied Force Wheel
Assembly]..............................................................................52
Figure 2.14: [Wheel Assem. Stress Grad
Impact]........................................................................53
Figure 2.15: [Wheel Assem. Strain Grad
Impact].........................................................................54
Figure 2.16: [Wheel Assem. Deform Impact]...............................................................................54
Figure 2.17: [Wheel Assem. FOS
Impact]....................................................................................55
Figure 2.18: [Wheel Assem. Torque and Weight
Loading]............................................................55
Figure 2.19: [Wheel Assem. Torque
FOS]....................................................................................56
Figure 2.20: [Wheel Assem. Torque
Strain]..................................................................................57
Figure 2.21: [Wheel Assem. Torque Deform]...............................................................................57
Figure 2.22: [Lower Control Arm Impact
Loading]........................................................................58
Figure 2.23: [Lower Control Arm Displ. Impact]..........................................................................59
Figure 2.24: [Lower Control Arm Strain Impact]..........................................................................59
Figure 2.25: [Lower Control Arm FOS Impact]............................................................................60
Figure 2.26: [Lower Control Arm Vert. Stress].............................................................................60
Figure 2.27: [Lower Control Arm Vert. Displ]...............................................................................60
Figure 2.28: [Lower Control Arm Vert.
Strain]...............................................................................61
Figure 2.29: [Lower Control Arm Vert.
FoS]..................................................................................62
Figure 2.30: [Shock
Solutions]......................................................................................................63
Figure 2.31: [165x40 Shock Solution]..........................................................................................65
Figure 2.34: [Full Suspension Test
FIt].........................................................................................67
Figure 2.35: [Non Pneumatic Wheel and Tire Assem]................................................................69
5

Figure 2.36: [Non Pneumatic Tire
Prototype]...............................................................................70
Figure 2.38: [Shock Absorber Model SolidWork]........................................................................71
Figure 2.39: [Side-by-Side Shock Setup]....................................................................................72
Figure 2.40: [Side-by-Side Control Arm Assem].........................................................................74
Figure 2.41: [Side-by-Side Proposed System v. Odyssey].........................................................77
2.0 List of Table
Table 1:Design Requirements of Motor and Gear Assembly......................................................22
Table 2:Design Requirements of Tires………………………......................................................22
Table 3:Design Requirements of Shocks Absorbers.................................................................23
Table 4:Design Requirements of Control Arms…………….......................................................24
Table 5:Compiled Tire FEA results……………...........................................................................51
Table 6:Compiled Shock Design Info……………........................................................................67
3.0 Abstract
This year the mechanical mobility subteam prioritized improvements for each component within
the sub-system. We are utilizing the Titan Rover Odyssey platform as our baseline for iterative
design changes. We have concluded that the mobility system equipped with Odyssey was robust,
an effort to design for strength and simplicity would be the overall goals.
6

The mobility system is split up into two subsystems: the drivetrain and the suspension. The
drivetrain system, which consists of the motors, wheels, and tires, is responsible for making the
rover move. On the other hand, the suspension system is responsible for smoothing out the ride
and keeping the rover in control as it traverses over a variety of harsh terrains.
Some advancements regarding the improvement of the drivetrain system include replacing the
motor with something more mechanically sufficient, simplifying and or modifying the wheel
hubs, and custom 3d printed tires. Along with that, the suspension subsystem will be modified
with a better shock option that is easy to maintain, easy to install and uninstall, lightweight, and
can sufficiently aid the Rover in its missions. Regarding the control arms, different material is
analyzed in order to cut some weight off of the system while keeping the control arms as strong
as possible. These changes are considered in order to improve the drivetrain and suspension
system for Rover mission operation.
3.1 Objectives
Extreme Retrieval and Delivery Mission: The rover will be required to collect a series of
objects in the field and deliver them to designated locations; providing service to fallen
astronauts. This task requires the rover to traverse multiple types of terrain and operate no more
7

than one kilometer beyond line of sight in the allotted time frames. Approximate GPS
coordinates are provided and objects to be retrieved involve fuel canisters, toolboxes,
lightweight tools, or rock specimens. This task consists of a series of stages and failure to
complete a stage ends the task.
4.0 Project background
Mobility focuses on the platform’s chassis, suspension, drivetrain (motors/gearbox), and
wheels/hubs. These are integral parts of the rover and ultimately, are responsible for the
movement of the entire platform. To comply with the URC size and weight restrictions, it is
essential to produce a lightweight chassis with versatile suspension that can withstand dynamic
forces from the robotic arm, science cache, and drivetrain assemblies. In addition, the chassis
must adhere to spatial constraints and must also consider efficiency in housing the suspension
system, onboard computers, and electrical/power components. Analysis of the mobility’s past
competition performance has proven that the current mobility system is robust and well
designed; however, the wheel hub assemblies are of complex geometry and are overengineered,
making them too expensive to manufacture.
4.1 Project History
Titan Rover is a legacy team which started in 2014 which consisted of a small group of STEM
students that created a Rover to compete in the URC. The very first Rover, ION utilized a 6
8

wheel, rocker-bogie design. In 2017, a major update to the Rover platform was created known as
Atlas, with notable changes in the suspension and drivetrain. The updated rover utilizes a dual
wishbone suspension system with onboard pneumatic shocks. The single motor gearbox system
per wheel and small tires were swapped with a geared dual motor drive and large polyurethane
balloon tires. Since Atlas, the Rover platforms to the current system have been iterations with
improvements and experimentations in various subsystems.
For the 2020-2021 Titan Rover team, the platform will be an iteration of the 2019, Odyssey
platform. Due to the nature of the dual wishbone suspension being a linkage system, the same
dimension will be re-incorporated to maintain the Rover ride height and suspension
compatibility.
4.2 Literature Survey
The main effort in the mobility subsystem has been diverted into each component to explore new
opportunities and to reduce weight. The tires and motors underwent a more significant amount of
9

research in order to determine suitability of proposed changes. The shock absorber and
suspensions system will undergo a minimal change in design and will therefore not be discussed
in this section.
4.2.1 Motors:
The dual brushed motor system has been a part of the Rover since its introduction in the Atlas
platform. The motor, coupler, and gearbox systems have provided sufficient speed and torque to
accomplish the necessary tasks. However, the motors would need to be replaced often, as they
have a very short operating life cycle. This creates a potential problem of reliability which needs
to be addressed while maintaining or exceeding in the following parameters: lightweight,
compact, cost beneficial, and suitable performance.
Figure A1. Diagram of a simplified BLDC rotor with a set of north and south permanent
magnets (Digi-Key's North American Editors).
Brushless DC (BLDC) motors appeared to be the most suitable replacement in order to increase
reliability in the system while providing better efficiency. According to one article, “BLDC
motors have a number of advantages over their brush brothers. For one, they’re more accurate in
positioning apps, relying on Hall effect position sensors for commutation. They also require less
and sometimes no maintenance due to the lack of brushes” (Dirjish). However, the cost of the
motors, gearbox, and new controls system would take up a significant amount of the allocated
mobility funds. Therefore, hub brushless DC motors were explored due to the lower priced, and
higher powered selections.
10

Despite the high torque, high speed, and low cost of the hub motors option, the weight is a major
drawback. With many of the suitable motors causing the Rover to exceed competition limits of
110 lbs or 50kg in a given mission. If a smaller hub motor is used it will not meet the compact
criterion as seen from figure A2 of such systems.
Figure A2. A geared hub drive using a sufficiently sized motor to power a reducer (Sun,
Cong, and Liao).
It was ultimately decided that a further investigation in the electrical control and power output to
the motor would be a more suitable area of improvement. The motor and gearbox system will be
evaluated further and a determination of replacement or improvement can be made.
4.2.2 Tires:
11

Figure A3. An airless tire patent, the spoke design is meant to act as both a method for
supporting the vehicle and absorbing road shock (Mun,Kim, and Choi).
The concept for tires in the 20-21’ platform are motivated by a goal to also reduce the wheel hub
complexity. Airless tires became a major choice due to the ability of 3D printing especially under
circumstances where a workshop shop was inaccessible, and the cost to machine and weld the
necessary parts were more than allowable. An initial search showed many patents for design of
airless tires and the commercial usage in small rough terrain vehicles such as in figure A4.
12

Figure A4. An airless tire concept called a TWEEL, by Michelin, for off road vehicle use
(“MICHELIN® X® TWEEL® Family of Products for ATVs and UTVs.”).
Further, the design of the spokes can be varied to increase or decrease the deformation behaviour
of the tire. The latter is demonstrated in a study titled “Design and Static Analysis of AirlessTyre
to Reduce Deformation”, where various spoke geometry were tested with the same load of 1200
N and different deformation were seen for tires of various spoke geometry (Mathew, Sahoo, and
Chakravarthy). The design is possible, however, it is still a fairly new concept, and the most
commonly seen methods either involve a mold or 3D printing. Both manufacturing methods
open possibilities for the mobility team to prototype and determine if the design is viable at a
scaled size.
Figure A5. A diagram for predicted airless tire concept and response based on material
(Mathew, Sahoo, and Chakravarthy).
5.0 Proposed Conceptual Design
The Mobility system will undergo minimal design changes. The double-wishbone with inboard
pneumatic shock suspension system will remain unchanged. The drive train will also remain
unchanged; it will continue to use dual-brush DC motors which are connected to a coupler
gearbox that outputs the power to the wheel hubs. Furthermore, the space frame chassis design
from previous years will be subjected to further implementation due to its structural rigidity and
large 4 Titan Rover internal volume for components. While the overall geometry of the space
13

frame chassis will remain, a shift in URC rules, will call for shortening the overall length of the
chassis; such that all rover components fit within a 1.2m x 1.2m area without disassembly. An
Acrylic plate will be secured to the bottom of the chassis to serve as a base plate for our
electrical and controls components. Relating to the wheels and wheel hubs, alternative geometry,
material, and manufacturing techniques will be considered with the goal of improving
manufacturability and optimizing wheel grip. The mobility team sees a lot of potential in
leveraging additive manufacturing technology to produce high strength-low- weight airless
wheels and wheel-hubs. Research and Testing will be conducted to analyze the strength and
performance of 3D printable polymers such as nylon. Once the chassis, wheels and wheel hubs
have been manufactured, we will conduct several testing scenarios with other sub-system
configurations to observe and analyze system performance.
5.1 Components of System
The suspension and drivetrain components are integrated to form the full mobility subsystem.
Both figures B1 and B2 provide a system view and model view of the mobility system
components.
14

Figure B1. A block diagram of the mobility subsystem based on the major components.
Figure B2. The mobility subsystem from the Calypso/Odyssey platform excluding the wheel
hub and tires.
5.1.1[Motor and Gearbox]
The motor and gearbox for the 20-21’ year platform will remain unchanged as the feasibility of
the BLDC and hub motors are unable to meet the necessary criteria to replace the brushed motors
without other Rover subsystem changes or extreme financial costs.
15

Figure B3. A solidworks model of the motor, coupler, and gearbox along with a portion of
the knuckle.
The selected motors are Banebots RS-775, with a 3.25:1 coupler, and 16:1 Banebots gearbox.
The gearbox shaft mounts to a coupling plate which has a key to transfer power between the
motor and wheels. The motor and gearbox are connected to a knuckle which acts as a support
and connection to the control arm. This system has provided mobility to the Rover since the
2017 Atlas platform.
No major redesign will be performed on the system after initial research led to solutions that
each lacked in at least one crucial requirement. In further collaboration with the electrical and
controls, an upgrade could be reconsidered. The system is likely to maintain a brushed motor
system due to the cost and development of controls needed to change to BLDC motors.
5.1.2[Tires and Wheel Hub]
The method of transferring power to the road surface is using a conventional wheel hub and tire
method. The design incorporates a 19.3 inch polyurethane low pressure balloon tire over a
6061-T6 Aluminum wheel hub as seen in figure B4. The tire system is capable of puncture repair
by heating the affected area to rejoin the polyurethane material. However, if punctured multiple
16

times, or if the tear is too large, then the pneumatic tire is unable to serve its function.
The spokes are designed as the first point of failure due to the complex manufacturing needed to
create the wheel hubs.
Figure B4. The polyurethane air tires attached to a wheel hub assembly.
Figure B5. A concept design for airless tires utilizing a uniform flexible material.
Airless tires are a major consideration for the 20-21’ platform based on the research surveys. An
example of an airless tire design is shown in figure B5. The major concerns regarding the airless
are the dynamic behavior of shear and bending acting on the spokes. Ideally a material that can
maintain high hardness while still having polyurethane properties would be ideal for creating
airless tire design. One major positive to choosing the airless tires is the ability to manufacture
17

with 3D printing. The airless tires can be scaled down slightly and the print setting can be tested
to obtain a balance between weight and performance.
5.1.3[Shock Absorber]
18

Figure B6. Model of the on board shock absorbers attached to the chassis mount.
The mobility team’s main goal regarding the shock absorber is to find a dimensional replacement
for the current shocks. The shock absorbers that are currently installed on the Rover originated
from the Odyssey’s platform, which was two years ago, thus will need replacing. When choosing
shock absorbers, the mobility team has set out some requirements that the upgraded set of shocks
should meet. These requirements include weight ranging below 0.6lbs and greater than 0.3lbs,
being able to withstand a 1 meter drop, and keeping the rover at a minimum ride height of 11
inches. To expand on these requirements, ideally, the new shock absorbers’ eyelet mount should
be of the same dimension as the current shocks and its external diameter should be about the
same or more compact compared to the current shocks.
The shocks that are currently onboard the Rover are pneumatic mountain bike shocks, more
specifically, the DNM A0-42AR. These weigh about 0.6lb when empty and 0.7lbs when filled
and are made out of Al-6061. It has an eye to eye dimension of 190mm with a travel distance of
48mm. We want our upgraded shocks to resemble this somewhat, thus making it a straight swap
without having to alter any mounts.
5.1.4[Dual Wishbone Suspension]
19

Figure B7. One set of dual wishbone control arms, the bottom control arm is designated by
the additional shock mount.
The dual wishbone suspension system is adopted from the Odyssey platform and will undergo a
material selection analysis to determine if any further weight can be cut without affecting the
strength of the assembly. The total length from the furthest edges is 10 inches while the length
between chassis mount and knuckle mount holes are 9.5 inches. The length of the control arms
determine the max and minimum ride height along with the tire diameter. The upper control arm
does not have any force response from the knuckle movement. Therefore the weight of the Rover
and any input forces are supported through the lower control arm. The shock mount sustains a
continuous perpendicular force due to the shock and lever mount orientation.
There are currently two other light-weight materials that can serve as replacements to the AISI
4130 steel, aluminum 6061-T6 and carbon fiber. Aluminum is considered for its high strength to
weight ratio, however there is still a significant sacrifice in maximum strength compared to the
baseline steel. Carbon fiber is another option which could potentially be used to create a low
density, high strength material in replacement to AISI 4130 steel. Although the carbon fiber can
potentially be manufactured at home, it may not be suitable if a mold cannot be made. It may be
possible that another material is considered after more situational force analysis of the control
arms are performed.
20

5.2 Requirements, Specifications, Projections
21

The sub-system requirements are derived from competition guidelines and conditions faced in
the simulated Mars environment at Hanksville, Utah. The design for this year's platform will be
an iteration of the Odyssey platform with mass decrease, complexity reduction, and performance
improvements as key design guides. The requirements for the mobility system are broken down
into drivetrain and suspension functions, which allow for a direct approach to each solution.
The overall goal for the mobility subteam is to reduce the subsystem mass by 10% which results
in approximately 4 lbs of weight. The qualitative goal is to perform analysis for each sub
assembly in order to provide more information on design changes to make.
5.2.1 Drivetrain
Motor
The key requirements of the motor subsystem is given in table 1 which the proposed solution
must satisfy. Since the system will undergo no change due to preliminary decisions failing to
meet either the torque or weight requirements; the existing system will be reanalyzed to
determine if the system output exceeds the projected requirements while accelerating.
The requirements are determined from a baseline feasibility study for expected situations during
mission traversal. Titan Rover should be able to overcome a 60° incline while accelerating at
least 1 ft/s2
. Additionally each mission will have a given amount of distance and time to
complete the task, therefore the Rover should be capable of exceeding a minimum speed
condition of approximately 1.11 mph. The projection did not take into consideration travel path,
therefore a 5 mph is imposed to account for the approximation. Additional mechanical
requirements could be considered before the final decision is made to continue with the legacy
drivetrain components.
Tabel 1. Design Requirements of Motor and Gear assembly
22

Design Parameter Requirement
Torque > 375 lb-in
Weight < 4 lbs per motor assembly
Minimum speed 5 mph
Tires
Since a more explorative option has been chosen, the tire design should fulfill the same
dimensions as the baseline air balloon polyurethane tires. The weight should be less than
baseline and must provide the same ride height of 11”-13” as the Odyssey platform. Currently
3D printed airless tires are under consideration utilizing flexible material. The material must
retain its shape in order to work effectively as a tire so a hardness parameter is set. The spoke
design and force projections have not yet been clearly defined as the structure does not conform
to usual models for rigid objects. The critical design parameters can be seen in table 2. Other
features such as increasing traction and more optimized design can be explored if a lower
designed weight can be achieved.
Tabel 2. Design Requirements of Tires
Weight < 4 lbs
Outer Diameter ≤ 19.3 in
Tire Width ≤ 9 in
Hardness ≥ Shore A 60
23

5.2.2 Suspension
Shocks
The pneumatic shocks must provide load support for both static and dynamic conditions. The
worst case scenarios and basic functions are used to determine suitability of the shock selection.
Since no fundamental changes will be made to the shock selection, an upgrade to a lower weight
shock absorber is the main objective. Therefore the requirements are that the shock be
dimensionally similar to the DNM-A0 42AR shock absorbers. The most critical requirement is
the eye to eye and travel length as well as cost and weight. The performance of the upgrade
selection shall either be measured or determined through other means.
Tabel 3. Design Requirements of Motor and Gearing
Design Parameters Requirements
Weight > 0.7lbs
Cost > $300 each
Ride Height Minimum of 11”
Strength Must withstand 1 meter drop / ~820lbf
Eye to Eye x Travel 7.48” x 1.88” [190 x 48 mm] (or similar)
Control Arms
24

The control arm will undergo no design changes in terms of geometry and will be derived from
the Odyssey platform. The main objective for the dual wishbone design will be to further reduce
weight of the control arms. The current AISI 4130 steel gives the total number of control arms a
mass of 2.97 lbs. The average mass of each control arm is about 0.37154 lbs meaning the team
should aim to reduce the mass by half. Analysis is performed in order to determine if the lower
control arm and shock system create a linkage system that generates a mechanical advantage of
less than 1, meaning a lower transmission of force to the chassis. More refined stress studies will
be performed to gauge the limitations of the circular tube design.
Tabel 4. Design Requirements of Control Arms
Weight < 0.6 lbs per control arm
Ride Height 11 in - 13 in
Mechanical Advantage ≤5
5.3 Analysis
25

The following are individual analyses performed for each major sub assembly of the mobility
system. The baseline feasibility for certain requirements are developed in order to determine
suitability of design and iteration choices. In addition, the model of the system is further defined
through analysis.
5.3.1 Motors
A comparative study is performed to determine if the Banebots RS-775 and gear system meet
mechanical baselines feasibility criteria. The situation under analysis is the Rover accelerating up
various inclines with a mass limit of 50 kg or 110 lbs. There is also a theoretical determination of
the speed output for the RS-775 driven system to compare with the service requirements in table
1.
Figure 1.1. The force diagram for a Rover on an incline of degree θ to determine drive
torque required.
The force situation in figure 1 is turned into a free body diagram as a method of force
simplification. The free body forces are assumed for the system undergoing constant acceleration
up various inclines. Equations of motion are determined along with the magnitude of forces
26

which are transmitted to the tire. From there a torque requirement is determined for a quarter
model of the Rover.
Figure 1.2. The torque requirements for various angles as a function of acceleration with a
constant coefficient of rolling friction Cr=0.4.
The project requirements of the drive system torque are shown in figure 2 for a single frictional
surface situation. It is determined that if an extreme situation is encountered such as a 60°
incline, and an acceleration greater than 2 ft/s2
, a torque of approximately 475 lbf-in will be
required. The constant acceleration situations are linear functions as the system is simplified to a
macroscopic situation where the Rover is not fluctuating its speed. It is expected that if the
system is able to perform under worst case conditions, then it will be able to overcome situations
which will not be as demanding. However, confirmation must still be obtained for such
consideration as the system may behave contrary to the prescribed mathematical model.
27

Titan Rover Senior Design Project Critical Design Review 2021

Titan Rover Senior Design Project Critical Design Review 2021

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Titan Rover Senior Design Project Critical Design Review 2021

Similar to Titan Rover Senior Design Project Critical Design Review 2021 (20)

More from KristopherKerames

More from KristopherKerames (6)

Recently uploaded

Recently uploaded (20)

Titan Rover Senior Design Project Critical Design Review 2021