This is one of the presentations I gave with my team, in the 2020-2021 school year, to demonstrate the final design of the Titan Rover senior design project that I co-led. Titan Rover is a legacy senior design project. Its main objective is to create a version of the Mars Rover for the University Rover Challenge.
1. Kit Kerames - Project Co-Lead
Van Nguyen - Project Co-Lead
Sasha Licari - Robotics Lead
Houston Tong - Drivetrain Lead
Axel Alvarez L. - Manufacturing/Chassis Lead
Axel Alvarez L. - Mechanical Science Lead
Hailey Ju - Electrical Lead
Robert Pace - Controls Lead
Tony Nguyen, Juan Alvarado, Haley Choi, Daniel
Velazquez, Jonathan Tang, Austyn Webster, Ajit Singh,
Adrian Throckmorton, Kevin Tran, Lily Park
2. Objectives
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
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.
Points earned by completing each task are as follows:
3. System Requirements
● Off-Grid, Teleoperated Platform
● Versatile Suspension
● Robotic Arm
● Electrical Distribution System
● Communications System
● User Controlled Interface
● Science Sample Collection System
● Field Serviceability
● Rapid Deployment
4. Design Parameters
According to University Rover Challenge rules 2021
Mission system mass
- To not exceed 50 kg (110lbs) for any given mission.
Overall mass
- To not exceed 70 kg (154bs) for all mission components.
Dimensional Constraint
- The rover must fit within a 1.2m x 1.2m (3.9ft x 3.9ft) square weighing plate. No
constraint on vertical height.
Safety Features
- All rovers shall have a “kill switch” that is readily visible and accessible on the exterior of
the rover
Task Time for each mission
-Teams are given a range of time to complete each task, is about 30–60 min for each
mission.
Cost of total system including base station must be under $18,000
5. Management Plan (SOW)
Proposal
Concept Design
Review
(30% completion)
Preliminary
Design Review
(60% completion)
Critical Design
Review
(Complete design)
Manufacturing
System
Integration/testing
Scope: Design/manufacture rover for University Rover Challenge, adhering to competition parameters.
10. Improvements to the platform
Roller chain pulley design
● Eliminated slippage in belt
● Removed preload needed for belt
Grippers Research
● Potential Designs
● Materials
● Improvements the original design
○ Powerful motors
Hex tool (Typer tool) research
● Potential Designs
● Materials
11. Minor Changes
Griper Research
● New potential designs
● Materials
● Improving original design
Typer Tool Research
● Potential new designs
● Improvements to original design
13. Sub-System Summary
● Proposed solutions for timing belt pulley
● Completed roller chain pulley design
○ Modeled in SolidWorks
● Researched Grippers and Typer Tool
● Prototyped Grippers
● Documentation
● Development Kits
14. Future development
● Chain Roller Pulley
○ Prototype and validate
○ Researching materials
○ Tested
● Grippers
○ Prototyped
○ Purchase new motors
○ Test the motors
● Typer/Hex Tool
○ Prototype
○ Test the design
○ New Improvements
16. Shock Changes
Legacy Shocks
2021 Shocks
- DNM A0-42AR
pneumatic single
chamber bike
shock
- 165 mm x 45 mm
max length and
piston travel
- 0.6 lb (empty)
- KindShock A5-
RR1 pneumatic
double chamber
bike shock
- 190mm x 50mm
max length and
piston travel
- 0.39lb (empty)
17. Shock Improvements
-Lower mechanical advantage, lower
force transfer to chassis
-Lower motion ratio, higher stiffness
-More space within Rover chassis
-1.2 lbm lighter overall, with new shocks
-Prevents chassis from bottoming out with
the ground
19. Preliminary Design
Figure A. Thin column spokes
Figure B. Thick honeycomb spokes
Figure C. Michelin Uptis based design
Figure D. Thin honeycomb spokes
20. Tire Changes
Legacy Tire Non-Pneumatic Tires
- Air tires 49 cm in
diameter
- Approx. 4lb per
tire fully filled
- Polyurethane,
smooth surface
- Non-pneumatic
tires, 29.5 cm in
diameter
- Approx. 2.5 lb per
tire
- 3D printed from
TPU with treads
21. Materials and Fabrication Tires
● TPU 95A Shore Hardness
● 3D Printing
○ 15% infill
○ 0.8mm Nozzle Print Size
○ Estimated 48 hrs to print
22. Wheel Changes
Wheel Hub
• Complete redesign of the wheel hub due to the non-pneumatic tire design
• The new design is easier to manufacture than the Odyssey model
• The number of manufactured parts reduced from 5 to 3
• The total subassembly weight has increased ~2 lbs (1.3 lbs to 3.4 lbs)
Legacy Wheels 2021 Wheels
23. Wheel Improvements
• The previous wheel hub was designed to accommodate
the inflatable tires
• The new spokes interlock with the NPT
• The new wheels have grooves to help keep the tire in
place
24. Materials and Fabrication Wheels
● The material for all of the components are Al 6061-T6
● This is the same materials as the previous models
● The spokes and wheel will be machined using a CNC milling and lathe machine
● The key mount will be reused from the previous year and the fasteners will be purchased
Key Mount Spokes Wheel
25. Control Arms Changes
Old Design New Design
Lower Control
Arm Assembly
Upper Control
Arm Assembly
Summary of Control
Arm Updates
● The control arms were re-
designed in search for a
stronger structure
● The material for the control
arms was also changed to
reduce the weight of the new
design and withstand the
necessary applied forces
● The lower control arm shock
mount was also re-designed
to fit the updated shock
mounting position
26. Material Properties Comparison Control Arms
Old Design New Design
● Upper Control Arm
○ Mass: 0.32 pounds
○ Material: AISI 4130 Steel
○ Yield Strength: 460000000 N/m^2
● Lower Control Arm
○ Mass: 0.71 pounds (with all
hardware and shock mount)
○ Material: AISI 4130 Steel
○ Yield Strength: 460000000 N/m^2
○ FOS: 0.60 for a 500 N impact load
● Upper Control Arm
○ Mass: 1.02 pounds
○ Material: AISI 1020 Steel
○ Yield Strength: 350000000 N/m^2
● Lower Control Arm
○ Mass: 1.21 pounds (with all
hardware and shock mount)
○ Material: AISI 1020 Steel
○ Yield Strength: 350000000 N/m^2
○ FOS: 1.8 for a 500 N impact load
27. Materials and Fabrication Control Arms
● AISI 1020 is commonly used to make agricultural, truck, and automotive
parts
● AISI 1020 Steel has good weldability and machinability
● This allows for welding of AISI 1020 steel plates to create the control
arms and shock mounts
● If any part needs some machining, it will also be feasible with this
material
28. Sub-System Summary
Updated Designs
-Non-pneumatic tires and new wheels
-Updated shock absorber geometry and
control arm design
-Computational analysis performed,
theoretically meets design requirements
29. Future Development
- Physical verification and validation of component function and stress
adherence.
- Review fabrication plans and verify suitability of materials and methods
chosen
- Iterate to reduce mass and evolve designs to withstand greater variety of
loading conditions
- Update to motor and gearing system, utilizing different control methods
or motor types
32. Improvements to Chassis made this year
Original Antenna mast
(odyssey) New antenna mast
New modified antenna mast
allows for the antenna to fold
along the length of the rover
for the weighing process
33. Chassis
● Stand added to chassis to allow it to stand upright during weigh-in
○ Enables us to extend wheelbase while falling within dimensional
constraints
● Antenna mast redesigned to be foldable and more compact
Figure shows FEA performed on hinge
34. Materials
● Aluminum 6061-T6 Square tubing
(Chassis frame material)
● Aluminum 6061-T6
(6”x6”x2” slab)
For rover antenna mast hinge
● Aluminum 6061-T6
Rod for the rover stand
35. Fabrication Plan
Fabrication Plan For chassis team:
● Chassis frame needs to be welded together, the proposed method of welding is TIG welding
● Antenna mast hinges need to be CNC machined out of aluminum 6061 T6
● Rover stand mount needs to be machined and the rubber stopper at the end of the stand may
need to be 3d printed or molded with a rubber material.
36. Sub-System Summary
● Rover antenna mast hinge redesign and
analysis
● Rover stand analysis
● Research on manufacturing techniques of for
both the chassis and the proposed new
components
● Documentation of components and research
38. Life-Detection
● Improvements to life-detection system include
○ Enhanced excavator strength
○ New material, ASA, used in soil distribution system to
minimize cross-contamination
○ More accurate life-detection components like the
fluorescence filter
39. Fluorescence Microscopy
We will now be using Fluorescence Microscopy instead of just the
microscope experiment to get some better results. This Fluorescence
Filter cube needed to be introduced. A laser is shot through the green
filter and bounced down to the sample below the box through a mirror,
reflected back up into the box, through another filter and observed
with a camera above the box.
Camera
40. Sub-System Summary
● Geneva gear not feasible.
● ASA/ABS material still needs to be
tested
● Fluorescence microscopy
experiment can be implemented as
a better test for life over microscope
experiment
● Test fluorescence cube could be
effective
Fluorescence Experiment
43. Testing Rover Code
• Physical Testing
– Test Benches
– System Testing
Past Procedure
• Remotely Test Code
– Linux Instance
– Allows Multiple
Users
– Processing power
• 1:1 Rover
– 3D Physics Engine
• Integration w/
ROS Software
Stack
Current Situation
• Remote Linux Instance
– VPS
– RDP
• Virtual Physics
Environment
– Gazebo
simulator
Solution
44. Robotic Arm Control
• Forward Kinematics
Solution
• Unintuitive HMI
Past Design
• Inverse Kinematics
Solution
• Give End User Better
Control
Research
• 4-Solution IK Model
• Hand Control
Interface
– Leap Motion
• WebXR
– Quest 2
– A-Frame
Current Plan
45. Inefficient Microcontrollers
• Pyboards
– Expensive
– Faulty Design
– Limited Features
Past Design
• Custom
Microcontrollers
• FPGA/CPLD
Research
• Custom STM32
Controllers
– Cheaper
– Customizable
• ASIC
– IDEs
Current Plan
46. Project Summary
● Objective: Design and build improved version of a Mars-like rover
● COVID-related restrictions forced a design-focused approach
● Plans for the future
○ Complete the manufacturing phase
○ Test rover in-person
● Design improvements were proven in simulations, and will give future students
a better chance of winning the University Rover Challenge
● Budget awarded $38,000 (includes funding from CSUF and from sponsorships)
○ Budget spent $3,200
