MECH202 Engineering Design Project Report

Group 11 – Kylie Hardisty, Ray Huff, Eric Lufkin, Will van Noordt
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PROJECT 2
CSU MECH 202
Group 11
Kylie Hardisty - kchar@rams.colostate.edu
Ray Huff - huffray@gmail.com
Eric Lufkin - eblufkin@rams.colostate.edu
Will van Noordt - willvanzero@gmail.com
CONTENTS
Title Page with Device Image……….….… ..[2]
Project Plan……………………………….… ..[3]
Specification Development…………….... ..[28]
Engineering Analysis……………………… .[37]
Concept Generation and Evaluation….….[45]
Device Description…………………………..[63]
Bill of Materials……………………………....[78]
Testing………………………………………...[81]
Reliability Analysis………………………....[89]
Safety Analysis……………………………...[97]
Service and Support Plan………………....[99]
Teamwork Analysis………………………..[103]
Failure Analysis……………………………[159]
Appendices…………………………………[163]

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The Device - “Salient Rhino” Mark V

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Project Plan
CSU MECH 202
Group 11
Task List………………….....[4]
Task Dependencies………..[5]
Project Planning……...…….[6]
Gantt Charts…………….....[17]
Project Dates………......…..[27]

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Task List
# Task Leader Objective statements
A
Concept
generation Kylie
Each team member contributes two design concepts.
Group compiled strengths of all designs to be refined into
a single design.
B Iterative testing Will
Main components of design made and vetted. Design
improved through results of testing.
C Prototyping Eric Tested components assembled into a working model.
D
Prototype
Testing Eric
Initial prototypes tested on track. Simulation of opposing
vehicles used to test all functions developed.
E
Engineering
Analysis Will
Application of engineering concepts to validate design
quantitatively.
F Design Review Will
Making changes to design informed by engineering
analysis and testing.
G Final Design Ray
Fully informed design based on previous testing and
analysis. Design support mechanisms.
H Final Testing Eric
Test final model on track. More strenuous testing than
initial testing. Final modifications.
I
Failure
Analysis Kylie
Identify weakpoints and design/build breakdown. Suggest
ideas for improved design.
J
Team Health
Analysis Ray
Evaluate team productivity. Identify strengths and
weaknesses in group chemistry.
K
Final Report
Compilation Kylie
Assemble documentation, typeset for submission.
Proofread for grammar and logic.

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Task Dependencies:
A B C D E F G H I J K
Concept Generation A A
Iterative Testing B X B
Prototyping C X X C
Prototype Testing D X X X D
Engineering Analysis E X X X E
Design Review F X X X X X F
Final Design G X X X X X X G
Final Testing H X X X X X X X H
Failure Analysis I X X X X X X X X I
Team Health Analysis J X X X X X X X X X J
Final Report Compilation K X X X X X X X X X X K

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Project Planning
Design Organization: MECH202 Project 2 Date: Apr 29, 2017
Proposed Product Name: Project 2
Task
A
Name of Task: Concept Generation
Objective:
Generate concepts that will complete the task requirements.
Deliverables:
Two design concepts contributed from each team member
List of ideas to be vetted for final design
Decisions needed:
Decision 1: How to compile and refine strengths of all designs into a single
design?
Personnel needed
Title: All Hours: 4
Time estimate
Total hours: 4 Lapsed time(include units): 4 hours
Sequence:
Predecessors: N/A Successors: B, C, D, E, F, G, H, I, J, K
Start Date: 1/31 Finish Date: 2/01
Costs:
Capital Equipment: $0 Disposables: $0
Team member: Ray Huff Prepared by: Kylie Hardisty
Team member: Will van Noort Checked by: Eric Lufkin
Team member: Kylie Hardisty Approved by: Ray Huff
Team member: Eric Lufkin
The Mechanical Design Process Designed by Professor David G. Ullman
Copyright 2008, McGraw Hill Form # 10.0

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Project Planning
Task
B
Name of Task: Iterative Testing
Objective:
Perform testing on initial concepts, improve design to reflect feedback.
Deliverables:
Elimination of poor or costly conceptual ideas
Framework for designing and manufacturing early prototypes
Decisions needed:
Decision 1: Which protocols to apply when testing?
Decision 2: Criteria for whether or not a concept has failed?
Personnel needed
Title: Designer Hours: 12
Title: Tester Hours: 12
Time estimate
Sequence:
Predecessors: A Successors: C, D, E, F, G, H, I, J, K
Costs:
Team member: Ray Huff Prepared by: Will van Noordt

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Project Planning
Task
C
Name of Task: Prototyping
Objective:
Assemble tested components into a working model.
Deliverables:
One fully assembled and functional model capable of being tested for further
design refinement
Decisions needed:
Decision 1: Which hardware to use in model assembly?
Decision 2: What techniques and processes to use in manufacturing?
Personnel needed
Title: Manufacturer Hours: 20
Time estimate
Sequence:
Predecessors: A, B Successors: D, E, F, G, H, I, J, K
Costs:
Team member: Ray Huff Prepared by: Eric Lufkin
Team member: Will van Noort Checked by: Will van Noordt

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Project Planning
Task
D
Name of Task: Prototype Testing
Objective:
Test initial prototypes on track. Simulate opposing vehicles used to test all
functions developed.
Deliverables:
Results of testing giving insight to design refinement and improvement
Identified project weak points
Decisions needed:
Decision 1: How should opposing vehicles and their various functions be
simulated?
Personnel needed
Time estimate
Sequence:
Predecessors: A, B, C Successors: F, G, H, I, J, K
Costs:

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Project Planning
Task
E
Name of Task: Engineering Analysis
Objective:
Analyze components, specifications, and dimensions with an engineering
approach and optimize design when possible.
Deliverables:
List of changes necessary to design optimization
Report containing detailed analysis and calculations, figures
Decisions needed:
Decision 1: What approach to use for each component?
Decision 2: What changes to implement, with costs and complexities taken
into consideration?
Personnel needed
Title: Engineer Hours: 15
Time estimate
Sequence:
Predecessors: A, B, C Successors: F, G, H, I, J, K
Costs:

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Project Planning
Task
F
Name of Task: Design Review
Objective:
Apply results of engineering analysis in the form of changes made to final
design.
Deliverables:
Final design concept ready for approval
Decisions needed:
Decision 1: Determine relative values of completely redesigning previous
prototypes and maintaining the ability to review design in a timely and
financially responsible manner
Personnel needed
Time estimate
Sequence:
Predecessors: A, B, C, D, E Successors: G, H, I, J, K
Costs:

12
Project Planning
Task
G
Name of Task: Final Design
Objective:
Produce fully informed design based on previous testing and analysis. Design
support mechanism.
Deliverables:
Final design drawings and notes
Final product for testing and competition
Support protocol and list of necessary tools for toolbox
Decisions needed:
Decision 1: What systems are most likely to fail and how to support them?
Decision 2: What systems from testing are most critical to improve or modify
for final production?
Personnel needed
Title: Engineer Hours: 8
Time estimate
Sequence:
Predecessors: A, B, C, D, E, F Successors: H, I, J, K
Costs:
Team member: Ray Huff Prepared by: Ray Huff

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Project Planning
Task
H
Name of Task: Final Testing
Objective:
Test final model on track, using more strenuous testing techniques than
prototype testing. Use test results to direct final design improvements.
Deliverables:
Test results of every function of project, giving insight in final design
improvement and modification
Final competition ready modification of the project
Decisions needed:
Decision 1: How to conduct realistic simulations of competing vehicles and
their various functions?
Decision 2: What final improvements/modifications to make on the project?
Personnel needed
Time estimate
Sequence:
Predecessors: A, B, C, D, E, F, G Successors: I, J, K
Costs:

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Project Planning
Task
I
Name of Task: Failure Analysis
Objective:
Identify weak points and design/build breakdown. Suggest ideas for improved
design.
Deliverables:
Failure analysis report
Decisions needed:
Decision 1: Why didn’t our car place in the top three in the competition?
Decision 2: What improvements could have been made to place in the top
three?
Personnel needed
Title: Manufacture Hours: 10
Time estimate
Sequence:
Predecessors: A, B, C, D, E, F, G, H Successors: J, K
Costs:

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Project Planning
Task
J
Name of Task: Team Health Analysis
Objective:
Evaluate team productivity. Identify strengths and weaknesses in group
chemistry.
Deliverables:
Report of team health during project
Decisions needed:
Decision 1: Did all team members participate equally and adequately for the
collective good?
Decision 2: Should corrective action be taken toward any students for lack of
performance?
Personnel needed
Title: Team Lead Hours: 2
Title: Team Member Hours: 1
Time estimate
Sequence:
Predecessors: A, B, C, D, E, F, G, H, I Successors: K
Costs:
Team member: Ray Huff Prepared by: Ray Huff

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Project Planning
Task
K
Name of Task: Final Report Compilation
Objective:
Assemble documentation, typeset for submission. Proofread for grammar and
logic.
Deliverables:
Finalized completed report
Decisions needed:
Decision 1: Who is doing which section of the report?
Personnel needed
Title: Team Lead Hours: 12
Title: Compliance Lead Hours: 12
Time estimate
Sequence:
Predecessors: A, B, C, D, E, F, G, H, I, J Successors: None
Costs:

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Gant Chart – Week 1

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Project Dates - Target versus actual
Task Target
deadline
Actual
completion
Days
delayed
Concept Generation 2/1 2/1 0
Project planning and GANTT
chart Due
2/16 2/16 0
Concept Generation Due 2/23 2/23 0
Iterative Testing 3/7 3/7 0
Prototyping 3/7 3/29 22
Prototype Testing 3/9 4/4 24
Engineering Analysis 3/19 4/8 20
Design Review 3/21 4/10 20
Final Design 3/28 4/17 20
Working Prototype Due 3/30 3/30 0
Testing Analysis Due 4/13 4/13 0
Final Testing 3/25 4/26 30
Failure Analysis 4/27 4/28 1
Team Health Analysis 4/29 4/29 0
Final Report Compilation 5/1 5/1 0
Failure Analysis Due 5/2 5/2 0
Final Report Due 5/2 5/2 0

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Specification
Development
CSU MECH 202
Group 11
QFD………………….............[29]
Competitive Analysis………..[30]

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Quality Function Deployment Reasoning
Competitive Analysis
Motor Driven Devices (Torque Oriented):
Fast (2)- Torque and speed tend to be inversely proportional to each other. A device
built for pushing would require high torque and not be capable of the same speeds as
devices built to travel around the track quickly.
High Pushing Capability (4)- Devices built for high torque outputs were intended for
pushing opposing devices.
Stays in Track (3)- Momentum plays a large role in a devices ability to stay in the track.
Torque oriented devices may tend to have larger masses and slower velocities than
speed oriented devices. What a torque oriented device lacked in velocity could be made
up for in its mass and vice versa for a speed oriented device. Although, the tendencies
for velocity and mass of these devices cannot be guaranteed. The optimization of a
device to achieve high torques would not make it any more or less cable of staying in
the track.
Capable of withstanding Collisions (3)- A torque oriented device would be more
capable of colliding with an opponent and continuing to achieve forward gain than a
device built for speed, so long as the device managed to stay in the track after collision.
Long Run Time (3)- The optimization of a device to achieve high torques would not
influence the run time of the device. The run time would be determined by the power
source used to achieve motion.
Yields consistent Results (2)- The optimization of a device to achieve high torques
would not influence the consistency of performance results. However, there are many
factors that determine the results when facing opposing devices of many different
configurations and styles.
Serviceable on Competition Day (3)- The optimization of a device to achieve high
torques would not influence how serviceable the device is on competition day.
Affordable (3)- The optimization of a device to achieve high torques would not
influence the cost of the device. Total cost of the device would be determined by the
specific motors and mechanisms incorporated in the devices design.
Simple (3)- The optimization of a device to achieve high torques would not influence the
simplicity of design. There are many ways to optimize a device to achieve high torques.
Simple methods can be implemented in a device to accomplish high torque outputs.
Motor Driven Devices (Speed Oriented):
Fast (5)- Devices optimized for speed were designed to travel around the track quickly.

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High Pushing Capability (2)- Torque and speed tend to be inversely proportional to
each other. A device built for speed would not likely be capable of the same pushing
power as a device built for torque.
Stays in Track (2)- Momentum plays a large role in a devices ability to stay in the track.
Speed oriented devices may tend to have larger velocities and smaller masses than
torque oriented devices. What a speed oriented device lacked in mass could be made
up for by its velocity and vice versa for a torque oriented device. Although, the
tendencies for velocity and mass of these devices cannot be guaranteed. The
optimization of a device to achieve high speeds would not make it any more or less
cable of staying in the track.
Capable of withstanding Collisions (2)- Speed oriented devices tend to have lower
pushing powers and would be less capable of colliding with an opposing device and
continuing to achieve forward gain, assuming the opponent managed to stay in the track
after collision.
Long Run Time (3)- The optimization of a device to achieve high speeds would not
Yields consistent Results (2)- The optimization of a device to achieve high speeds
would not influence the consistency of performance results. However, there are many
factors that determine the results when facing opposing devices of many different
configurations and styles.
Serviceable on Competition Day (3)- The optimization of a device to achieve high
speeds would not influence how serviceable the device is on competition day.
Affordable (3)- The optimization of a device to achieve high speeds would not influence
the cost of the device. Total cost of the device would be determined by the specific
motors and mechanisms incorporated in the devices design.
Simple (3)- The optimization of a device to achieve high speeds would not influence the
simplicity of design. There are many ways to optimize a device to achieve high speeds.
Simple methods can be implemented in a device to accomplish high speed outputs.
Motor Driven Devices (Expanding Frame):
Fast (2)- The incorporation of an expanding frame in a device creates tension along the
track walls. This tension creates friction and prevents expanding frame devices from
achieving high speeds.
High Pushing Capability (5)- The tension force due to the frame expansion in these
devices act as the normal force and thus determines the friction force that resists
backward motion of the device from opposing devices.

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Stays in Track (4)- The tension force due to the frame expansion in these devices act
as the normal force and thus determines the friction force that keeps the device in the
track.
Capable of withstanding Collisions (5)- Due to the high frictional forces associated
with these devices, expanding frame devices perform excellently in withstanding
collisions form oncoming devices and continuing to achieve forward gain.
Long Run Time (3)- The incorporation of an expanding frame in a device would not
Yields consistent Results (4)- The incorporation of an expanding frame in a device
ensures the device comes in contact with an opposing vehicle. This results in the device
functioning as intended much more consistently when opposing many varieties of
opponent configurations and styles.
Serviceable on Competition Day (2)- The incorporation of an expanding frame in a
device would require more moving components than other designs. This could make
servicing the device on competition day more challenging.
Affordable (3)- The incorporation of an expanding frame in a device would not
influence the cost of the device. Total cost of the device would be determined by the
specific motors and mechanisms incorporated in the devices design.
Simple (1)- The incorporation of an expanding frame in a device requires more moving
parts that complicate the design.
Mechanical Energy Powered Devices:
Fast (3)- Mechanically powered devices are limited in the amount of potential energy
they can store while fallowing given project parameters (i.e. size, weight). This limits the
maximum speed achieved by such devices.
High Pushing Capability (1)- Mechanically powered devices are limited in the amount
of potential energy they can store while fallowing given project parameters (i.e. size,
weight). This limits the pushing capability of such devices.
Stays in Track (2)- Mechanically powered devices will likely be small due to their
limitations in storing potential energy. A small device would be more likely to get
knocked out of the track by an opponent.
Capable of withstanding Collisions (1)- Mechanically powered devices are limited in
their ability to store to potential energy and will not likely compare to electrically
powered devices in regards to speed or torque. It is unlikely a mechanically powered
device would be able to achieve any forward gain after a collision.
Long Run Time (1)- Mechanically powered devices, using springs, elastic, or other
such mechanisms for motion, only have so much potential energy to release. After this

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energy is gone, the device will become static. Electrically powered devices run on the
chemical reactions occurring inside the battery and are much more effective in the
terms of run time.
Yields consistent Results (1)- Due to the limitations in potential energy and short run
times of mechanically powered devices, they do not achieve high marks in consistency
against the variety of opponent configurations and styles.
Serviceable on Competition Day (2)- The mechanisms used to utilize purely
mechanical sources to power a device tend to be complicated compared to electrical
power sources that only require to be plugged into a battery.
Affordable (5)- Simple mechanisms capable of storing potential energy are much
cheaper than electrical components.
Simple (5)- Many mechanically powered devices only require simple mechanisms
without any complication from wires and other circuitry.
Target Values
Maximum Torque of Motor(s):
Delighted (30 N-cm)- We chose to take the specifications of a Nextrox Mini DC
electric motor found online (Nextrox).
Disgusted (10 N-cm)- We chose to take one third of our delighted value as our
disgusted value.
Maximum Speed of Motor(s):
Delighted (60rpm)- We chose to take the specifications of a Nextrox Mini DC
electric motor found online (Nextrox).
Disgusted (20rpm)- We chose to take one third of our delighted value as our
disgusted value.
Coefficient of Friction from Wheels:
Delighted (.6)- We chose to use values of brick on wood for this value ("Friction
and Friction Coefficients.").
Disgusted (.25)-We chose to use values of wood on wood for this value
("Friction and Friction Coefficients.").
Tension Force Applied to Track Walls:
Delighted (35.6 N)- We decided to take the equivalent weight force of two
vehicles at the maximum allowable weight for our delighted value.

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Disgusted (11.9 N)- We decided to take one third of our delighted value for our
disgusted value.
Maximum Pushing Weight:
Delighted (8 lb)- We chose to take twice the maximum allowable weight of a
device for our delighted value.
Disgusted (2.7 lb)- We chose to take one third our delighted value for our
disgusted value.
Battery Voltage:
Delighted (12V)- We chose to take this value as it is a standard voltage used in
many RC hobby projects.
Disgusted (1.5V)- We chose to take the voltage of one double A battery.
Battery Milliamp Capacity:
Delighted (2200mAH)- We chose to take the values of a common milliamp
standard used in may RC hobby projects.
Disgusted (733mAH)- We chose to take one third of the delighted value for our
disgusted value.
Number of Motors:
Delighted (2)- We chose two motors as our delighted values because we believe
this would be the maximum amount of motors we could realistically fit into the
project size and weight parameters.
Disgusted (1)- We chose one motor as our disgusted value as this is the
minimum amount of motors that could be incorporated
Percentage of Successful Testing Deployments:
Delighted (98%)- We chose this value because, although 100% deployment
success is desirable, we did not see it as a completely realistic goal.
Disgusted (85%)- We chose this value because we needed to beat six heats to
win the competition and this value would statistically result in one failure per
every seven deployments.
Fill of 3D Printed Material:
Delighted (100%)- We chose this value because it would result in the maximum
strength of a device.
Disgusted (33%)- We chose to take one third of our delighted value for our
disgusted value.

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Average Time per Lap (not weighted):
Delighted (3.15 sec)- We chose this value because it was the maximum rating
achieved by a team in the class during the prototype testing.
Disgusted (60 sec)- We chose this value arbitrarily for a device designed for
high torque will not likely travel nearly as fast as our delighted value.
Weight:
Delighted (4 lb)- We chose this value because it was the maximum allowable
weight for the device parameters.
Disgusted (1.3 lb)- We chose to take one third of the delighted value for our
disgusted value.
Total Cost:
Delighted ($50)- We chose this value for delighted as we didn’t think it would be
realistic to make a project any cheaper.
Disgusted ($200)- We chose this value for disgusted as it was the maximum
allowable cost given the project parameters.
Number of Contact Parts during Collison:
Delighted (1)- We chose this value because it is the minimum amount of contact
parts possible.
Disgusted (3)- We chose to take three times our delighted value for our
disgusted value.
Maximum Withstandable Impact Momentum:
Delighted (5.4 N-s)- We chose to use the maximum impact momentum resulting
from a 4lb object moving at 3 m/s.
Disgusted (1.8 N-s)- We chose to use one third of our delighted value for our
disgusted value.
Engineering Specifications Defined
Maximum Torque of Motor(s)- This refers to the maximum torque value of the motor
itself. This was given by the motor manufacturer’s specifications in ideal voltage
conditions and therefore is not related to the voltage of the battery we chose to use.
Maximum Speed of Motor(s)- This refers to the maximum rotations per minute value
of the motor itself. This was given by the motor manufacturer’s specifications in ideal
voltage conditions and therefore is not related to the voltage of the battery we chose to
use. The speed of the motor does not necessarily correlate to the speed of our device

36
because it does not account for slipping between the wheel and track surfaces.
Although, a faster motor would result in a faster device given no slipping would occur.
Coefficient of Friction from Wheels- This refers to the value for mu, allowing
calculations to be made for force of friction from a given normal force. The coefficient of
friction is a material property, independent of the surface areas in contact. This value is
not the same as the force of friction. This means, as the normal force applied to our
device goes up, mu will not change, although the total friction force will increase.
Tension Force Applied to Track Walls- This refers to the force applied to the track
walls, horizontally, by the expanding body of our device.
Maximum Pushing Weight- This refers to the maximum weight a device was able to
push.
Battery Voltage- This refers to the specifications of the batteries used in a device. With
a higher voltage rating, motors will generally spin with more power and at higher
speeds.
Battery Milliamp Capacity- This refers to the specification of the batteries used in a
device. A higher milliamp capacity will allow the battery to supply power for longer
periods of time.
Number of Motors- The number of motors incorporated in a device would influence
weight, cost, and the pushing power a device was capable of outputting.
Percentage of Successful Testing Deployments- This refers to the devices ability to
be activated with a single motion and function in the track as intended.
Fill of 3D Printed Material- This refers to the percent of a 3D printed parts internal
structure that is solid. The fill of a printed part determines the strength of the part. A
higher fill would require more material, adding weight a cost to a device.

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Engineering
Analysis
CSU MECH 202
Group 11
Engineering Analysis…………….....[38]

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Concept Generation
and Selection
CSU MECH 202
Group 11
Brain Storming……………...........[46]
Morphology Chart……………......[49]
Mind Map……………...................[52]
Function List…………..................[53]
Concept Drawings………….........[56]
Belief Map……………..................[62]

46
Brain Storming
All team members came up with three design concepts. These concepts and their pros
and cons were discussed. Design features were compared to see how different features
could be implemented together to generate a design concept for project 2.
High Speed:
The vehicle could be designed only to travel around the track very quickly with hopes to
make it further than the competing vehicle.
Pros:
• Could allow for very simple designs
• Although the design would not be able to defend against other vehicles, it might
be more optimal to achieve the primary objective of the competition: traveling the
furthest around the track
Cons:
• Would not feature any defense mechanisms and would likely be compromised
upon the first collision with oncoming vehicles
• Relies on the competitions lack of ability to travel around the track in the allotted
time
Pushing Opponents:
The vehicle could be designed to resist oncoming vehicles and push them.
Pros:
• Would result in a negative travel distance on any vehicle we pushed
• Would require a heavy vehicle
o Might make our vehicle slow
Cons:
• Project weight limits might make it hard to optimize our vehicle to push opposing
vehicles
Ramped Front:
The ramp on the front of our vehicle would be a simple means to attempt to throw
oncoming vehicles out of the track.
Pros:
• Could easily be incorporated into many different project designs
• A very simple, light weight means of defense
Cons:
• Likely be a very common design feature of competing vehicles
• Would only function in one direction
o Ramp would have to be detachable or vehicle design would need two
ramps to be capable of functioning in either direction

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Frame Expansion:
Upon start, our vehicle would expand to fill the entire width of the track. It could achieve
this using springs to expand horizontally, springs and a hinged joint to expand angularly,
or a radially expanding design.
Pros:
• Would not leave any space for opposing vehicles to squeeze by
• Allow our vehicle to be driven forward by wheels in contact with the sides of the
track
o Provide tension/traction to resist oncoming vehicles
o Provide a simple solution to allow our vehicle to make track turns
o Could mount wheels at a downward angle, keeping our vehicle in the track
o A simple solution to make our vehicle capable of running the track at
either direction
o Could maximize efficiency of the wheels in the means of forward
movement by mounting drive wheel to the inner radius of the track
Cons:
• Would increase the complexity of the vehicles design
• Would be rendered useless if an opposing vehicle lifted us out of the track
Pulling Opponents:
Upon start, our vehicle could be designed to hook onto the back of competing vehicles
and pull them.
Pros:
• Would result in a negative travel distance on any vehicle we pushed
• Likely wouldn’t be a sabotage tactic our competition would expect or design their
vehicles to handle
Cons:
• Hard to make a design that could hook onto every possible competitor design
• Might be hard to make a vehicle capable of pulling other vehicles
• A vehicle designed to pull others would likely not be very fast and would not
travel far if the initial competitor hook-up didn’t work
Electromagnetic Pulse:
Creating a vehicle that, upon impact with a colliding vehicle, would discharge a very
large capacitor into a solenoid aimed at the opposing vehicle. This would fry any
circuitry used in competitor’s design.
Pros:
• Would render competitors requiring circuitry useless upon collision
• Could be incorporated to many different vehicle designs
Cons:
• Might miss and not have an effect on competitors
• Might fry our own vehicles circuit components
• Would not have any effect on a vehicle that did not require circuit components to
function

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Carrying Opponents:
Creating a vehicle that utilized a ramp and catching system to carry opponents.
Pros:
• Would result in a negative travel distance on any vehicle we carried
• Would be simple compared to many other features to sabotage competing
vehicles
• Would not have to resist opposing vehicles force if vehicle was being carried
Cons:
• Might require an expanding frame to ensure opposing vehicles would collide with
our vehicle and be able to be carried by our vehicle
o Might result in a slow moving vehicle
• Would need a vehicle capable of carrying other vehicles
o Might make for a heavy, slow moving vehicle

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Morphology Chart Defined
Propulsion:
Stepper motor- using a stepper motor to provide power to our vehicles wheels
Servo motor- using a servo motor to provide power to our vehicles wheels
DC motor- using a DC motor to provide power to our vehicles wheels
Pneumatic- using a small compressed CO2 tank to provide forward propulsion of our
vehicle
Potential energy- using springs, flywheels, and other systems that can provide kinetic
energy from stored potential energy to drive our vehicle
Defense:
Carrying competing vehicles- allowing opponents to ride up on top of our vehicle
where they will run into a wall, no longer be capable of moving forward, and be carried
in the negative direction
Catapult- creating a device that will fling opposing vehicles off the track via a spring
loaded mechanism
Electromagnetic pulse- discharging a large capacitor into a solenoid aimed at
oncoming vehicles, frying the electrical components of competitors
Lifting competition with ramp- creating a simple ramp shaped plow to attempt to
careen opposing vehicles off the track
Competitor towing capability- creating a mechanism that would attach to the back of
competing vehicles upon start, allowing our vehicle to pull them in the negative direction
Bypass opponents- creating a device capable of rolling or flying over oncoming
vehicles
Locking:
Bladed wheels- creating wheels with a geometry that would dig into track surfaces and
resist backward movement

51
Ratcheting device- creating a mechanical ratcheting device that would only allow
vehicles wheel axels to spin in one direction
Dredge pins- creating dredge pins that would drag behind our vehicle and, when
opposed by a competitor, dig into the track surface and resist our vehicle from flipping
Expanding frame- creating an expanding frame that would allow our vehicle to press
up against the tracks sides and provide tension to resist opposing vehicles
Expanding Frame:
Springs- using linear springs to allow our vehicles frame to expand to the sides of the
track
ACME rod- using an ACME rod that would allow our vehicles frame to expand to the
sides of the track
Pneumatic solenoid- using pneumatic pistons to allow our vehicles frame to expand to
the sides of the track
Hinged opening- using angular springs and a hinged joint to allow our vehicles frame
to expand to the sides of the track
Radial expansion- creating a vehicle that expands radially to the sides of the track

52

53
Functions
Propulsion:
Ability to propel vehicle around the track as many times as possible in 3 minutes.
Defense:
Ability to evade or neutralize opponent’s offensive tactics.
We considered a plow to be a defensive device used to stop opponents from hindering our
progress around the track.
Offense:
Ability to hinder the opponent’s progress around the track.
We considered a ramp to be an offensive device used to attempt to throw the opponents out of
the track and hinder their progress.
Expansion:
Ability to expand and fill the full width of the track.

54
Propulsion
Defense
Offense
30 0 0 -1 1 1 1
5 0 0 -1 1 1 0
10 0 -1 -1 -1 1 1
5 0 -1 0 -1 1 -1
25 0 0 0 -1 0 1
25 0 0 0 -1 -1 -1
0 -15 -45 -30 25 35Satisfaction
Baseline:
DCMotor
ServoMotor
StepperMotor
Penumatic
Issue: Propel vehicle around the track as many
times as possible in 3 minutes.
Size
Ease of integration
Cost effectiveness
Driving force
ElasticEnergy
Rocket
Boosters
Project Criteria
Mass efficiency
Longevity
10 0 1 0 1
5 0 1 1 1
20 0 -1 0 0
5 0 -1 0 0
20 0 -1 1 1
40 0 1 1 1
0 10 65 75
Baseline:
Plow
Bypass
Opponents
DredgePin
Locking
WheelLocking
Issue: Ability to evade/nuetralize
opponent offensive tactics.
Project Criteria
Satisfaction
Mass efficiency
Size
Ease of integration
Cost effectiveness
Versatility
Reliability
25 0 -1 1 -1
10 0 -1 1 0
15 0 -1 -1 -1
10 0 -1 1 -1
25 0 0 -1 -1
15 0 0 -1 -1
0 -60 -10 -90
Baseline:
Ramp
Catapult
EMP
TowCable
Issue: Ability to hinder the
opponents progress around
Project Criteria
Satisfaction
Mass efficiency
Size
Ease of integration
Cost effectiveness
Versatility
Reliability

55
Expanding frame
10 0 -1 -1 0 1
15 0 -1 -1 0 -1
5 0 -1 -1 0 0
30 0 -1 -1 1 -1
30 0 1 1 0 -1
0 -30 -30 30 -65
Mass efficiency
Baseline:
LinearSprings
ACMERods
Pneumatic
Solenoid
Hinged
Opening
Radial
Expansion
Issue: Ability to expand and fill
the full width of the track.
Project Criteria
Satisfaction
Holding Tension
Reliability
Cost effectiveness
Ease of integration

56

57

58

59

60

61

62
Belief Map

63
Device Description
CSU MECH 202
Group 11
Analogies……………..........................[64]
Concept Development……………......[65]
Prototype Iterations……………...........[69]

64
Analogies
At the outset of the team’s design considerations, it was identified that significant
pushing power would be the focus of the team’s device design. Due to a weight limit of
4 pounds, it was determined that no robot would be able to provide more than
approximately 4 pounds of pushing force, assuming usage of materials that did not
exhibit a coefficient of friction against the wooden track of 1 or greater. Building on this
assumption, the team began a search for analogies of devices, organic and inorganic,
that were able to produce a large pushing force by pushing outward against a barrier. In
the case of this competition, the barrier available would be the ¾ inch walls of the track,
and the device would have to expand in a fashion that its drivers could provide this
pressure against the walls. The following analogies were noted for this expansion
function:
Martial arts wall splits:
Martial artists have been known to go to great lengths to gain a height
advantage. Sometimes this means holding one’s body weight aloft by doing the splits
between walls. This demonstrates using a powerful horizontal compressive force to
achieve a large vertical one. It was postulated that the device being designed could use
this horizontal compressive action to give it a greater pushing force than simply
depending on the force of weight.
Car jack:
A simple mechanism that produces a strong compressive force many times its
weight is a car jack. Jacks will either employ hydraulic pumps or simple mechanical
advantage with a lead screw to lift several thousand pounds, while the jack itself weighs

65
10 or 20 pounds. While the goals for this device were not as lofty as a 100x force
multiplication, the basic mechanism of a car jack was the beginning inspiration for the
design of the device.
Concept Development
Inspired by the mechanism of the car jack, a similar mechanism was developed.
The main difference here was the need for a much quicker deployment than the version
pictured above which is actuated using a lead screw. The initial concept depended on a
four-member mechanism that would be spring loaded to compress in the y-direction,
and expand in the x.

66
As seen in the sketch notes, it was quickly identified that while the elastic force
driving the expansion would cause a quick actuation, its large change in length would
also severely limit its holding force once expansion had been completed. This is backed
by an application of Hooke’s law for spring tension:
𝐹𝑠𝑝𝑟𝑖𝑛𝑔 = 𝑥 ∙ 𝑘
Where Fspring is the force produced by the spring, x is the spring length beyond its
resting length, and k is the spring constant for the given spring. According to this, the
contraction in spring length will lead to a proportional drop in the spring force produced.

67
A second, compound mechanism was developed in an attempt to minimize this change
in spring length.

68
While the compound mechanism showed improvements over the simple linear
expansion idea, further consideration led to the development of an angular expansion
mechanism that would allow compression force against the walls of the track using a
torsion spring between two frames that would act as moment arms. The design could
provide a very small change in angle, which would address an angular equivalent of the
linear Hooke’s law equation above. The main variable would the length of the moment
arm frame components, and while height was not constrained in any way for this
project, the moment arms could be as long as needed to minimize the change in angle,
as long as they were not too long to manufacture or to minimize the compressive force

69
of the spring moment they created. It was determined that this concept was best tested
with a preliminary prototype that need not move, but which would simply demonstrate
the expansion function and inform regarding its practicality or impracticality.
Prototype Iterations
Mark 0
The first physical prototype we made was just the basic shape and action we
envisioned. Some of the issues Mark 0 had was that it didn’t move due to the lack of
drive wheel, motor, or battery and, therefore, was not a functioning prototype. There
was also not enough room to fit a substantial sized drive wheel into the slot provided.
Several design and manufacturing issues were noted during this preliminary
iteration. Firstly, the resulting strain that the torsion spring produced on the 3D printed
plastic caused the frame to crack. This was aggravated by the use of ABS in the 3D
printing process, which produced a frame that exhibited weaknesses between the
printing layers. It was decided that for large prints such as this, a more suitable plastic
would need to be utilized.
The bending action of the frame also produced a change in angle of the torsion
spring that was larger than the spring design allowed. After successive compressions,

70
the torsion spring deformed to the point of not providing the full force that was needed to
keep the frame open against the track.
This design also lacked a mechanism to hold the device closed while being
measured. It was determined that a latching mechanism would be necessary in
subsequent designs. Lastly there was no way to attach the motor to the device in a
secure fashion. This was to be expected, as the motors for the device had not been
decided and ordered, so there were no specs to design mounting holes to.
Mark 1
For the second iteration, attempts were made to address and correct all issues
identified in Mark 0. In addition, it was desired that Mark 1 would have the ability
to move in addition to expanding. The first thing fixed was the device’s ability to

71
move. This issue was addressed by widening the slot in the drive wheel side so
as to fit a wheel hub and tire. A mounted plate for the motor was printed and heat
inserts were fused into the device body to hold it in place. Lastly, a high
discharge lithium polymer battery was procured to power the motor. With these
drivetrain additions, Mark 1 was a self-propelled prototype that successfully
drove around the track using the desired compression-drive system against the
walls of the track. A motor mount was developed for the newly acquired high-
torque DC motor. Which bolted to the main frame.
To fix the issue of the torsion spring cracking the device body, a higher grade
of plastic in the printing process so the frame could withstand the stresses applied to it.
INOVA-1800 was available from the Idea2Product Lab, donated by a local company,
and its interlayer adhesion, strong tensile strength, and low thermal contraction made it
idea for this prototyping. Finally, the team incorporated a small door latch mechanism to
hold the device shut until it was time to deploy the device.
New issues that surfaced with Mark 1. The violence of the expansion produced
by the unconstrained torsion spring caused the motor arm to swing directly up and out
of the track. No system had been anticipated to dampen the opening force produced by
the torsion spring. The force was so strong that it would cause our device to swing out
of the track, removing the drive wheels from the track entirely, which would render the
entire device useless in competition.

72
The second issue was that when the device went around a curve the back-idler
wheel lost contact with the track which cause the device to become jammed and unable
to move. Too much material had been designed as a fender around the idler wheels,
which would have to be removed in the next CAD iteration. It was also noted that no slot
had been designed to hold the battery, which would be necessary for the next iteration.
Mark 2

73
Mark 2 fixed the main issue of how to dampen the torsion spring loaded
expansion. To fix this we decided to use pneumatic dampeners in the form of
needleless syringes. This form of dampening made it so when the device opened it
would slow the process of opening but not take way from the total tension force. Our
first attempt at finding a way to fix the tilting that would cause our idler wheel to lose
contact with the track was to add “bumpers” on the drive wheel side, so that when our
device would tilt the bumpers would prevent the device from being torqued completely
out of position and losing all contact with the idler wheel and inner wall. The last thing
this prototype modified was the ability to hold the battery in place. This was
accomplished by an indent for the battery shape to fit into as well as extruded brim that
would hold the batter in place.
Issues we had with this model was that we did not have enough spring force and
therefore, not enough tension on the side walls. Secondly, even though we added the
slot for the battery it didn’t hold it solidly enough and it tended to slip to one side or
another and fall off the device.
Mark 3
Mark 3 was the device we designed directly after the seeding trials. During these
trials, Dr. Gadomski suggested we use a linaer expansion system instead of the radial

74
one we had been using due to the geometry and the spring force produced by the
torsion spring. We couldn’t come up with a linear expansion mechanism that would fit in
the dimension paraments. Instead we incorporated a damping system that allowed the
mechanism to open at a slower controlled rate to prevent it from over shooting the track
walls upon release. The twin syringe dampers provided a good balance for the small
tension springs used in Mark 2, but the it was desired after seeding trials that more
compression be achieved for more pushing force, as Mark 2 had barely been able to
push the wooden block.
We decided to use linear tension spring as a replacement for the torsion springs
because they were available in a larger variety, and were easily incorporated into our
design by adding a 3D printed lever arm incorporated in the idler frame. This redesign
fixed the issue of not having enough spring force and, consequently, tension on the side
walls. To fix the issue of the battery slipping out we decided the most versatile solution
was put a semi-lose zip tie around the battery so we would be able to easy insert and
remove so charging would be simplest.
Issues with this Mark that we were still vulnerable of getting torqued out of
position on the curves and when contacting another object. The other issue we had was
that we still needed to come up with some form of defense mechanism. We had many
previous conversation about how to incorporate such an apparatus as a ramp to get
under other devices, but had yet to find an effective way to integrate it.
Mark 4
This iteration represented a very significant design change in that we decided
to add another motor and driving wheel. We did this counteract the tendency to torque
out of place. The addition of a second motor also effectively doubled the device’s

75
pushing power. To be able to accomplish this we had to completely redesign and reprint
the drive side of our device. Consequently, the dampeners had to be moved to the
center of the device in-between the motors. Originally, the 3-wheel design was chosen
to be able to corner without a change in the separation of the wheels. Geometric
analysis revealed that a 4-wheel design would keep all wheels tangent to the radii of the
track, granted that the suspension would provide flexibility for a changing wheel
separation distance. Because the expansion mechanism was providing this flexibility in
wheel base reliably, it was deemed safe to add a second drive wheel. Finally, we added
our first attempt at a defensive ramp to this Mark was well. Two ramp designs were
produced and used in the first round of testing.
The issues that arose when testing this iteration was that the ramp had a
tendency to snap at the hinge joint that attached it to the frame. This had been
anticipated and the ramp was designed to be easily replaceable whereas the body of
the device was not. This ensured that the ramp would be the first point of failure rather
than the frame, which would be highly desirable during competition, as the frame would
not be at all practical to replace.
Another difficulty was that the addition of a second point of driven motion
caused the device to not be able to stand stationary before it was activated. The
previous iterations had balanced on standoffs next to the single drive wheel. Those
standoffs had been removed for the addition of a second drive wheel, and would now
need to be replaced by a single standoff between the drive wheels. There was much
work done in the design phase before Mark 5 to determine the optimal positioning and
length of this standoff so as not to interfere with the drive wheels, but to still extend out
enough to balance the standing device prior to activation.

76
Mark 5
The sixth and final iteration, deemed the Salient Rhino, incorporated the
summation of the lessons learned with the previous iterations. The device had a
redesigned ramp that distributed force of impact to be parallel to the track surface.
Previous testing showed that a vertical moment was produced when the ram was hit
with enough momentum. The new design would direct all that impact force horizontally
to the wheels and avoid pushing our vehicle out of the track. To accomplish this, the
designer added a tab on the bottom of the ramp that would push against body of the
vehicle to distribute the impact force. The new standoff was long enough to fix the

77
wheels moving the device when it was in the start position. To add clearance, wheels
were pushed as far up the motor shaft as possible while still leaving enough clearance
to properly rotate and move the device.
Device Operation
Operation of the final device was as follows: first the operator plugged the
motor into the battery and used electrical tape secure the connection. Direction of
motion was determined by the polarity of the connection, as the DC motors were simply
reversible according to the polarity of their connection to the battery. The motors were
connected in parallel to ensure a full 11.1 volts to each motor.
Next, the operator compressed the expansion mechanism, folded the ramps
up behind adjustable tabs on the side to hold them vertical, and latched the frame
closed using the door latch. After the device was set down in the track, it was activated
by unlatching the holding mechanism, causing the device to expand by means of the
quad spring force. Acceleration of expansion was slowed by the pneumatic dampers
which provided a resistive force when the plungers compressed. Once the device was
opened, the springs applied force to the sides of the track, causing forward motion from
the two drive wheels which would already be turning upon connection with the battery.
Further testing revealed that the Rhino could indeed push over three times its
weight due to the firm compressive force of the drive wheels against the walls of the
track. Testing against competitors showed that the ramps were slightly lifted off the
track, so the ramp angle was adjusted and metal plates were added to improve their
durability and ability to slide beneath opponents’ plows. All systems that had been
designed in this iteration worked with impressive reliability.

78
Bill of Materials
CSU MECH 202
Group 11
Bill of Materials……………...........[79]

79
Bill of Materials
Product : Salient Rhino - Mark V Date: Apr 29, 2017
Item # Qty Name Cost Material Manufacturing Process
1 1 Motor frame $0 INOVA-1800 3D printed
2 1 Idler frame $0 INOVA-1800 3D printed
3 6 Ramp left $0 INOVA-1800 3D printed
4 6 Ramp right $0 INOVA-1800 3D printed
5 1 Motor shield $0 ABS 3D printed
6 2 Syringe pin $0 INOVA-1800 3D printed
7 2 Idler tire $0 Ninjaflex 3D printed
8 2 Motor wheel hub $0 INOVA-1800 3D printed
9 2 Motor tire $0 Ninjaflex 3D printed
10 1 ¼” x 5” bolt $1.20 Steel Stamped, rolled
11 1 ¼” lock washer $0.14 Steel, silicone Stamped, tapped
12 10 ¼” washer $0.50 Steel Stamped
13 8 ¼” bushing $2.40 Aluminum Stamped
14 4 Large spring $0.98 Spring steel Wound
15 2 Syringe $0 HDPE Injection molded
16 2 M2.5 x 15 SHCS $0 Steel Stamped, rolled
17 2 M2.5 nuts $0 Steel Stamped, tapped
18 1 2 mm OD iron rod $1.10 Iron Extruded
19 2 Large zip tie $0 Nylon Injection molded
20 1 LIPO battery $16.95 Lithium Ion Electronic assembly
21 1 1 ft 20 AWG wire $0 Copper, polymer Extruded
22 2 12V geared DC motor $25.96 Steel, iron, copper Electronic assembly
23 2 M8 x 10 FHCS $0.48 Steel Stamped, rolled
24 4 M8 washer $.20 Iron Stamped
25 2 M8 nut $0.28 Iron Stamped, tapped
Team member: Eric Lufkin Prepared by: Ray Huff
Team member: Kylie Hardisty Checked by: Will van Noordt
Team member: Ray Huff Approved by: Ray Huff
Team member: Will van Noordt Page 1 / 2

80
Bill of Materials
Product : Salient Rhino - Mark V Date: Apr 29, 2017
Item # Qty Name Cost Material Manufacturing Process
26 2 608 bearing $0 Stainless steel Stamped, rolled
27 3 M4 x 50 screw $1.32 Steel Stamped, rolled
28 6 M4 washers $.72 Steel Stamped
29 3 M4 nuts $.36 Steel Stamped, tapped
30 4 Rubber band $.08 Rubber Injection molded
31 4 Steel strips $8.00 Stainless steel Cold rolled
32
1
RC battery
charger $11.99 Plastic, copper Electronic assembly
33
34
35
Notes:
>> 3D printed material donated by Idea2Product lab for staff educational usage.
Material usage estimated at $20 for Mark V, and $55 for all other prototypes.
>> Syringes procured freely from Walmart Pharmacy
>> Bearings, wire, and other items sourced from donated Ricoh parts in A8
Total Mark V cost: $72.99
Additional $23.50 for prototyping cost, miscellaneous parts, etc.
____________________________________________________
Grand total group expenditure: $96.49
Team member: Eric Lufkin Prepared by: Ray Huff
Team member: Kylie Hardisty Checked by: Will van Noordt
Team member: Ray Huff Approved by: Ray Huff
Team member: Will van Noordt Page 2 / 2

81
Testing
CSU MECH 202
Group 11
Testing…………….......................[82]

82
Testing
Table 1: Weight of objects used to test
Object Weight (Pounds)
Large Aluminum Block 1.42
Brass Block .635
Small Aluminum Block .1125
Black Magnet .109
Green Magnet .209
Large Core .581
Grinder 3.1
Wood Block 2.766
Cardboard Block .2785
Mark 3 Testing
For Mark 3 we only conducted one test to determine the max pushing weight
when the device collided with a weighed down cardboard box. We tested this using
Mark 3 as to give ourselves a base line to compare Mark 4 to since that prototype was
having two major design changes of a second motor and additional springs being
incorporated.
Table 2: Max Pushing Weight Results for Mark 3
Trail Number Total Weight Pushed (Pounds)
1 5.9165
2 5.1085
3 3.959
4 (with one added spring) 6.138
As can be seen from the trials the numbers for pushing were not consistently in
the same range. But what we did learn from this testing though was that our belief that
more tension gave more pushing power, as seen in the fourth trial, was proven correct.
Our group also calculated the coefficient of static friction between the box and
the wooden track. To do so the cardboard box was put on the left and right side
straightaways multiple times and then the table was lifted until the box began to slip and
the height was measured.

83
Table 3: Table Lift Heights
Left Side Height (inches) Right Side Height (inches)
33 35.5
31.5 34.5
The average height we used in our calculation was 33.125 inches and using the
trigonometric tangent function (1) with the total length of the track being 97 inches we
found that the coefficient of static friction was .363
tan(
𝐴𝑣𝑒𝑟𝑎𝑔𝑒 𝐻𝑒𝑖𝑔ℎ𝑡
𝑇𝑜𝑡𝑎𝑙 𝐿𝑒𝑛𝑔𝑡ℎ
) = µs (1)
Mark 4 Testing
For our fifth iteration, we put it though two tests. First one being a similar test
Mark 3 was put through to find its maximum pushing power but what we changed was
that found the maximum pushing power on the straightaways and curves. The numbers
presented below are the maximums we found that our device could consistently push
three times in a row and we classified a push as our device not stopping for more than
one second after it impacts the cardboard box. We did this pushing test 3 times with
three different tires to figure out which one gave us the best pushing force. The last
thing we wanted to figure out in the test was when we found the best wheel type to use
was if putting the drive wheels on the inside of the track would give up more pushing
power compared to when they are on the outside.
Knobby NinjaFlex Tires
Table 4: Max Pushing Weight Results for NinjaFlex
Placement Max Pushing Weight
(Pounds)
Straightaway 6.484
Curve 9.238
Drive wheels on the inside Failed at Max Weight

84
Rubber Band Wrapped Tires
Table 5: Max Pushing Weight Results for Rubber Band Wrap
Rubber Band Wrapped Core Only
Table 6: Max Pushing Weight Results for Core Only
Max Pushing Results
We decided to hybridize the knobby NinjaFlex tires with the rubber band wrapped
tired because while the rubber bands gave us more pushing power they were easily
ripped due to the forces exerted on the wheels. We didn’t want to use only the rubber
band wrapped tired because if the rubber bands were to completely snap we would
have been left with the nearly frictionless drive wheel. By combing the two tire designs
we get the reliability of the NinjaFlex tire if the rubber bands were to all snap off as well
as the high friction of the rubber bands while they are connected. We ruled out the
rubber band wrapped core only because they did not give us nearly as much pushing
power on the straightaway and curves as the other two. This type of tire also didn’t give
us the NinjaFlex as backup.
(Pounds)
Straightaway 7.3875
Curve 9.238
(Pounds)
Straightaway 4.4735
Curve 8.27

85
Figure 1: Rubber band wrapped wheel destruction
Figure 2: Rubber band wrapped core only destruction
Impact Momentum Test
The second test we ran was an impact momentum test to analyze how our
device preformed during high impact simulations and how we could optimize our ramps
to get the best results. We tested two different ramp designs against a simulated
opponent, that we designed and printed, that had a ramp in the design to simulate what
would happen if an actual competitor had a ramp on their device. We made it designed
like this because we knew a lot of teams would have some form of ramp because it was
the most obvious offensive mechanism so we wanted to figure out how to defend
against it. To do this we weighted the simulated opponent to four pounds as that was

86
the max any actual opponent could way and then dropped down it down ramp from
different heights and recorded if it passed or failed the impact and described what
happened during and after the impact. For this test passed meant that the impact didn’t
stop us from make forward gain, while failed meant we were permanently stopped in
some capacity.
Figure 3: Ramp one design
Figure 3: Ramp Two design

87
Table 7: Ramp design one impact test
Table 8: Ramp design two impact test
Impact Momentum Test Results
As can clearly see in the tables above the second ramp design did much better
than the first design. For the second ramp when the simulated opponent was dropped
from 18.5 inches the ramp would snap off do to the impact but our device would
continue moving forward, unlike the first ramp design that would snap off as well but the
device was always pushed out of the track due to the impact. From these observations
we concluded that the second ramp design was better at absorbing the initial impact
then the first ramp design. Our final ramp design looks very similar to the second test
design but slightly altered so it would fit in the dimensions as well as it was slightly
redesigned to distribute some of the impact force into the body of the device instead of
just at the hinge it was screwed into.
Height (Inches) Trial 1 Trail 2 Trial 3
14.5 Pass Pass Pass
18.5 Fail Pass Fail
Height (Inches) Trial 1 Trail 2 Trial 3
14.5 Pass Pass Pass
18.5 Pass Pass Pass
Figure 4: Top view of final ramp design

88
Figure 5: Bottom view of final ramp

89
Reliability Analysis
CSU MECH 202
Group 11
FMEA…………….........................[90]
FTA……………............................[95]
Reliability Analysis…………….....[96]

90
Failure Mode Effect Analysis (FMEA)
# Functio
n
Potentia
l failure
modes
Potentia
l failure
effects
Potentia
l causes
of
failure
Recommen
ded actions
Responsi
ble
person
Taken
actions
1 Propulsi
on
Expansi
on
causes
motor
frame to
swing
upward
Wheels
no
longer
constrain
ed by
track, will
not
propel
device
Expansi
on action
is too
forceful
and
pushes
motor
frame
above
track
walls
Install
damper
system to
slow angular
acceleration
of expansion
mechanism
Eric L. Installed
damper
system
next to
springs.
Also
found that
expandin
g from the
middle of
the track
alleviates
the issue.
2 Propulsi
on
Obstructi
on or
opponen
t lifts
device
from
track
Wheels
no
longer
constrain
ed by
track, will
not
propel
device
Opposin
g team
uses a
wedge
or plow
that gets
under
device
and lifts
it up
Design a
ramp that is
in contact
with the
track at all
times to
subvert
attacking
plow
mechanisms
Ray H. Designed
two
plows,
tested
both
against
test
dummy,
improved
design
and
implemen
ted into
final
device

91
# Functio
n
Potentia
l failure
modes
Potentia
l failure
effects
Potentia
l causes
of
failure
Recommen
ded actions
Responsi
ble
person
Taken
actions
3 Propulsi
on
Impact
causes
device to
tilt up
and
drive out
of track
Wheels
no
longer
constrain
ed by
track, will
not
propel
device
Heavy
impact
against
plow or
front
surface
of device
tilts it
upward
Weigh down
device to
prevent tilt,
direct force
to driving
wheels and
not produce
an upward
moment.
Ray H.,
Will v. N.
Designed
slot for
adding
weight to
front of
device.
Created
wedge on
plow that
transfers
impact
forces to
drive
wheels at
the
bottom of
the frame.
4 Propulsi
on
Device
turns at
a sharp
(usually
90
degree)
angle
Wheels
will no
longer
be
pressing
outward
against
track but
will
freewhee
l in the
air
Obstructi
on
causes
drive
wheels
to rotate
the
whole
device
rather
than
driving it
forward
Spread
wheels out
to their
maximum
allowed
distance to
maximize
stability
against
walls. Also
increase
spring
tension to
force wheels
apart,
resisting
device
rotation.
Will v. N. Moved
wheels
out to
maximum
separatio
n on
motor and
idler
frame.
Designed
spacing
for two
extra
expansio
n springs.

92
# Functio
n
Potentia
l failure
modes
Potentia
l failure
effects
Potentia
l causes
of
failure
Recommen
ded actions
Responsi
ble
person
Taken
actions
5 Propulsi
on
Wheels
stop
turning
No
forward
motion
possible
if wheels
stop
turning
Electrical
short,
break in
wire,
battery
drained
Secure
wiring
better, keep
battery
charged, do
not reuse
damaged
wire, ensure
that circuit is
properly
insulated.
Eric L. Charged
battery
before
and
between
races.
Used
tape and
zip ties to
keep
battery
securely
connecte
d to
motors.
Crimped
wires
securely
to motor.
6 Propulsi
on
Wheels
stop
turning
No
forward
motion
possible
if wheels
stop
turning
Enough
pushing
force
from
obstructi
on or
opposing
device to
overpow
er
motors
Increase
pushing
power
without
going over
weight or
sacrificing
ability to turn
Will v. N. Designed
4-wheel
design
instead of
3, with
two driven
wheels on
either
side of
the car.

93
# Functio
n
Potentia
l failure
modes
Potentia
l failure
effects
Potentia
l causes
of
failure
Recommen
ded actions
Responsi
ble
person
Taken
actions
7 Propulsi
on
Wheels
spin
freely
No
forward
motion
possible
if wheels
not in
contact
with
track
Obstructi
on
wedged
between
motor
frame
and
track
Develop
fenders and
ramp to
direct
projections
and debris
around
wheels and
not between
track
Ray H. Plows
designed
to direct
projection
s and
debris
upward.
Fenders
extended
around
wheel
8 Propulsi
on
Wheels
spin
freely
No
forward
motion
possible
if wheels
not in
contact
with
track
Insufficie
nt
traction
between
drive
wheels
and
track
wall
Test multiple
wheel
materials to
develop best
pushing
material
Ray H. Ran tests
with
various
wheel
types to
find
material
with
highest
coefficient
of friction.
Designed
hybrid
wheel
using
Ninjaflex
and
rubber
bands.

94
# Functio
n
Potentia
l failure
modes
Potentia
l failure
effects
Potentia
l causes
of
failure
Recommen
ded actions
Responsi
ble
person
Taken
actions
9 Ramp
deploym
ent
Ramps
fail to
drop
down
onto
track
Ramps
undeploy
ed will
leave
device
vulnerabl
e to
opponen
t plows
Insufficie
nt weight
force
pulling
ramp
down
onto
track
Add springs
to ramps to
pull them
downward
onto track,
and keep
them flat
against the
surface
Ray H. Springs
added to
pull ramp
down
toward
track.
Ramps
3D
printed
with
maximum
infill for
more
weight
1
0
Expansi
on
mechani
sm
Device
fails to
expand
against
track
walls as
intended
No
expansio
n against
track
walls will
disallow
the
wheels
from
driving
device
forward
Expansi
on
mechani
sm gets
caught
Optimize
expansion
latch for
easy
activation.
Keep
expansion
mechanism
clear of
anything
catching.
Eric L.,
Ray H.
Machined
latch to a
custom fit
for perfect
deployme
nt. Design
had large
clearance
in all parts
to prevent
catching.

95
Fault Tree Analysis (FTA)

96
FTA Notes
Due to the low probability of a UFO abduction, it was chosen to not further
extrapolate that event on the FTA.
Due to the short duration of the competition, it was deemed very unlikely that the
tire wear on wheels would present a substantial disadvantage in the competition and did
not warrant further exploration. While further testing did reveal that the rubber bands on
the wheel could indeed wear to the point of failure, it was decided that the support team
would replace the rubber bands in between each competition run.
Reliability Analysis
Our reliability was based off of results from testing our device against another
MECH202 team’s device. We held twelve individual trial runs against the team, in
which, the fallowing results seen in Table (XX) were recorded. Out of the twelve trials,
our device failure to deploy ramps once, did not remain stationary in the starting position
once, failed to wedge its ramps under the opponent twice, was pushed by the opponent
once, and was beaten in number of laps completed in three minutes by the opponent
once. This resulted in an overall reliability of 58.85%, meaning our device should
theoretically lose approximately four of every ten heats during competition day.
Task Success
Rate
1) Device turned on 100%
2) Device expanded to track walls 100%
3) Device was stationary in starting position 91.67%
4) Ramps deployed properly 91.67%
5) Ramps wedged under opponent 83.33%
6) Opponent was pushed 91.67%
7) Device completed more laps in 3 min than
opponent
91.67%
Reliability=R1*R2*R3*R4*R5*R6*R7 58.85%

97
Safety Analysis
CSU MECH 202
Group 11
Safety Analysis……………...........[98]

98
Fortunately, the device had few safety concerns. The operation of the device
during the final competition was as designed with one exception, where the leads on the
battery were briefly shorted together to produce a large, uninhibited current and,
consequently, sparks.
Table 1: The safety concerns and their respective preventative measures
Safety
Concern
Description Preventative Measure Concern
Level
Electrical
shock
Battery leads shorted
together
Use caution when
connecting battery power to
device, insert leads one at a
time.
Moderate
Pinch Hinge, ramps closed before
operator has cleared
extremities
Use caution when
closing/folding the device for
use.
Low
Laceration Operator cuts themselves
on sharp ramp edge
Treat ends of a device as if
handling a sharp object
Very Low
Abrasion Operator allows extremities
to become wedged in
between rotating wheels
and device frame
Keep extremities away from
wheels whilst they are on, as
well as from other moving
parts.
Moderate

99
Service and
Support Plan
CSU MECH 202
Group 11
Service and Support Plan……………...........[100]
Device Service and Support Kit……………..[101]

100
Service and Support Plan
There are many failure methods to consider when designing a device to compete
against other teams. It was decided to make most of the device out of 3D printed
ENOVA-1800 polymer due to the rapid production rates of 3D printing and the ease of
making spare replacement parts to use on competition day if necessary. Furthermore, a
tool kit was organized containing the basic tools necessary to install these replacement
parts, along with various other fasteners, adhesives, and hardware. Based on the
device seeding trials, the device would be facing five other teams in total to win the
competition. Some parts of the device, the ramps in particular, were designed to break
upon high enough impacts and were fully intended to be replaced. The contents of the
tool kit developed can be view in Table (XX) below.
The device was designed with two spring loaded ramps to wedge under
oncoming vehicles and prevent our device from being driven upward. Impact testing
resulted in multiple ramp design iterations and multiple broken ramps. As the ramps
were the initial point of contact with opponents, they were thus designed to be the first
point of failure of our device. The “disposable” design of the ramps would help to ensure
the body of the device was not damaged under high impacts. Ten ramps were made
(five left ramps and five right ramps). Each ramp was individually assembled with the
necessary hardware to mount to the device, including two M3 hex bolts and one tension
spring. This allowed ramps to be switched by re-installation of the ramp axel bolt and
installation of a single 6mm hex bolt, significantly decreasing the tooling time on
competition day.
In addition to replacement parts and hardware obtained before competition,
secondary drive mechanisms, such as motors and power sources, were considered. An
additional battery was purchased to serve as a backup power source in the event our
primary batteries charge depleted and was no longer capable of powering the device.
The battery was mounted to the device body in a 3D printed slot and held secure with a
single zip tie. This would serve as an effective means to support the battery under large
impacts while still allowing for quick battery replacement. Due to the device geometry, it
would have been difficult to replace either of the two motors incorporated on the driving
side of the design. It was also deemed unlikely that a motor would fail and need
replacing during competition. For this reason, a secondary motor was not purchased.
One of the most effective means of device service and support on competition
day is preventative design considerations before competition. With this in mind, a 3D
printed motor housing was made. This snapped over the two motors and protected our
drive components and their wiring. This also effectively protected the springs and
dampers used in device expansion from oncoming devices. The simple snapping design
allowed for protection without sacrificing the ability to service any damages that could
occur on the drive system during competition.

101
Device Service and Support Kit
Replacement Part Quantity Description
Replacement Ramp
(Left)
5
Ramps were assembled with sheet metal edge
and mounting hardware pre-installed
Replacement Ramp
(Right)
5
Ramps were assembled with sheet metal edge
and mounting hardware pre-installed
Replacement Drive
Wheels
2
The rubbery outside of the drive wheels
experienced a lot of stress during operation
Motor Cover 1
An additional motor cover was produced in the
event the primary cover failed
Battery 1
Both batteries ran off the same charger and were
fully charged prior to competition
Replacement
Hardware
Ramp Axel Bolt 4
Each additional axel bolt was purchased with the
appropriate nut for mounting
Additional Ramp
Hardware
4
This included an M3x10 and M3x6 hex bolt and a
10mm long tension spring
Idler Wheel
Bearings
2
Replacement bearings were collected in the
unlikely event of idler wheel failure
Replacement Latch 1
This secondary latch was pre-installed and
optimized for device initiation
Replacement
Expansion Springs
2
It was unlikely expansion springs would be
damaged during competition
Syringe Dampers 2
It was unlikely syringe dampers would be
damaged during competition
Additional Items
Battery Charger 1
The primary battery was pulled from the device
and charged between heats
Super Glue 2
A quick drying adhesive was added as a last
stand for any damages to the device body
Electrical Tape 1
This was used around the battery wires to ensure
they remained connected during collisions
Gorilla Tape 1
This served as a means for last minute fixes to
any damages to the device body
Zip ties 20
This served as a means for supporting any loose
parts of the device
Wire 1
This was incorporated into the kit in the event that
any wires had become severed

102
Rubber Bands 50
These were wrapped around the drive wheels to
increase overall pushing power
Tools
Hex Keys 3
All hex keys required to assemble/disassemble
the device were added to the kit
Monkey Wrench 1
A single monkey wrench would be necessary to
take apart the body of the device
Leatherman Multi-
tool
1
This was added to the kit due to its functionality in
many mechanical situations
Needle Nose Pliers 1
These pliers included wire snippers to mitigate
any problems in wiring that could occur
Rat Tail File 1
A large file would prove useful in the event the
device did not fit into size specifications
Needle Files 5
Needle files were used to make slight
modifications to 3D prints
Philips Head Screw
Driver
1
This would be used if the body of the device was
required to be taken apart

103
Teamwork Analysis
CSU MECH 202
Group 11
Team Contract…………….............................[104]
Lessons Learned…………….........................[105]
Reflection - Ray Huff……………...................[106]
CATME Results – Ray Huff…………............[107]
Reflection – Eric Lufkin……………...............[119]
CATME Results – Eric Lufkin………….........[120]
Reflection – Kylie Hardisty……………..........[132]
CATME Results – Kylie Hardisty ……….......[134]
Reflection – Will van Noordt……………........[146]
CATME Results – Will van Noordt………......[147]

104
Team Contract – Group 11
Design Organization: MECH202 Project 2 Date: March 10, 2017
Team Member Roles Signature
Will van Noordt Principle Designer
Ray Huff Project Leader
Eric Lufkin Head of Manufacturing
Kylie Hardisty Project Compliance
Manager
Team Goals Responsible Member
1. At least one meeting a week Ray
2. Set at least one deadline per meeting All
3. Take meeting notes Will
4. Hold each other accountable for deadlines All
5. Comprehensively align with rules and
requirements
Kylie
6. Quality assurance for manufactured parts Eric
7. Keep track of project files and documentation Eric
8. Ensure timely and reasonable progress Ray
9. Carefully document analysis Will
10. Troubleshoot unforeseen issues Kylie
Team Performance Expectations
• Meet deadlines, attend meetings
• Employ intelligent testing procedures
• Maintain a clear awareness of the group’s aspirations and ideas
• Project meets requirements and reflects reasonable effort on the
team’s part
• Strive for a grade of 90% or higher for each ancillary component
• Understand and embrace individual responsibility
• Give early notice if problem arises
Initial
Strategies for Conflict Resolution:
• Address in a timely manor
• Clear, concise, and unequivocal communication regarding the nature of the problem
• When problems arise, Team Lead will talk to team member about issue one-on-one and
discuss resolutions to the problem
• When problems persist, conduct a team health meeting with all group members to discuss
solutions to behavioral issue
• Defer conflict resolution to TA’s and/or professor if absolutely necessary

105
Meeting Minutes – see Appendix A
Lessons Learned
Early on in our design process, we utilized 3D printing to rapidly produce
prototypes. Each prototype gave us quantitative and qualitative results that allowed us
to trouble shoot our design concepts and make improvements that were vital to our
devices success. In the end, six prototypes were developed. Being on top of prototyping
early on in the design process gave our team an edge over our competition. Using
many device iterations and testing proved to be one of the most effective means of
design improvement. It is also worth noting how useful 3D printing is in the rapid
development of device prototypes.
We learned that it was highly beneficial to meet up with other MECH202 teams
and compete with their device before competition day. We were able to do this with one
other team the week before competition and it proved to be the most useful testing for
device concept generation for the final design. This not only gave us confidence in
some of the design concepts of our Mark IV prototype, but also lead us to improved
ramp geometries and the incorporation of a metal edge to the ramp and rubber bands
around our drive wheels for increased pushing power. Due to these improvements in
our ramp design, we were never wedged up by an opponent's ramp during competition
day. This was of our greatest concern in our design. It would be of great value to
complete more testing simulations with opposing teams prior to competition day.
During the competition, our device failed when an opposing team we had been
successfully pushing became wedged between our device and the device walls. This
had not been something we had predicted while designing our device. When this
occurred, both devices came to a standstill approximately 6 inches from the halfway
point on the track. With greater speed, we may have still become wedged between our
opponent and the track walls, however, this may have occurred after we had pushed
our opponent across the halfway point allowing us to have won the heat. We could have
accomplished this by choosing to run our drive wheels off of the inner radius of the track
and would still likely have had enough pushing power to achieve forward gain after
contact with our opponent. However, this was not a thought we had during competition.
It would have been valuable to have spent more time thinking about competition day
strategy.
One area of struggle was in the management of the final report compilation. We
found that as the competition day grew closer, the team focus went into the final
iteration of our device and not in the compilation of the report. After the competition, we
were behind and hand to cram to get the final report together. Our team was able to
produce a satisfactory report well within deadlines. In the future, it would be a benefit
while working on any project to remember to focus on the big picture and not just on
one aspect of the project.

106
Reflection – Ray Huff
Project two presented significant challenges as team lead. Initiating project 2
concurrently with project 1, it was difficult to keep track of progress and keep up
momentum on both fronts. Our team decided to focus on project 1 and complete it as
early as possible in order to be more focused on each project. This worked well for us in
managing our resources, but it did limit time to meet deadlines for project 2 as the
majority of the work was begun in mid-March.
The anxiety, anticipation, and uncertainty of the project’s culmination in a
competition added to the variables of the project. Time and care had to be dedicated to
monitoring team stability as competition day approached. Short nights of sleep and long
hours designing and building the device caused notable fluctuation in team dynamics.
We presented a strong, united front on competition day, but took our loss in the Elite 8
bracket with much disappointment because of the time put into producing a competitive
device.
CATME ratings taken in March indicated that my communication with the team
was not nearly as good as I had hoped it had been in project 1. I did what I could to step
up the communication to the team in person, using our GroupMe, and over email. If
communication does not remain strong, the team surely will have a feeling of being lost
and out of the loop, one of the main responsibilities of a strong lead member.
Comparatively and encouragingly, my self-ratings for the final CATME survey
were much closer to how I was rated by my groupmates. This reassured that the efforts
I had taken to improve communication and keep up a spirit of hard work were effective
and received by my group mates.
Regardless of the results of the competition, there remained a strong
camaraderie and positive energy in compiling our development process into writing the
final report. Much effort was put forth by all team members from the moment the
competition was over, and I myself was inspired to give my all to make this the best
report of the semester. With this enthusiasm, we proceeded to write nearly a full report
in roughly 48 hours, to a quality that matched our goals for this project and the class.
Our team proved to me that you don’t need a win to achieve a victory.

107
CATME Results – Ray Huff 1

108

109

110

111

112

113

114

115

116

117

118

119
Reflection – Eric Lufkin
In any engineering project I may play a part in, it is of the greatest importance
that I understand how to communicate with team members and work effectively in a
group environment to complete task objectives. The most efficient teams are made up
of individuals that can manage their own time with their group members and each fill a
unique role to move the team forward and successfully reach team goals. Project 2 of
MECH202 presented many situations that tested such attributes and have helped me as
an individual be a better, more effective team player while completing technical work in
a group setting. It is important to reflect on these learning moments, as they will define
my ability to perform in the real-world after college.
During project 2, in particular, I experienced just how important understanding
each of your team member’s abilities and strengths can be. For instance, Will is an
excellent modeler and Ray has made prototyping six different iterations possible with
his skillset in 3D printing. I have the most experience in machining, however, this was
not necessary to develop our final project. It would be far more efficient for me to let Will
handle the complicated modeling and Ray to handle the 3D printing than to try to take
these on myself, obviously offering help when I could be of assistance. Instead, I
focused my time and skills in areas that I could be most effective for the group in. This
ended up being design concept generation and report documentation. I believe
understanding individual’s strengths and weaknesses and filling unique individual team
roles accordingly allows a team to optimize task management and be most efficient in
the use of time.
I feel that my team struggled the most in the communication of deadlines. On
multiple occasions, we found ourselves working double time to complete assignments
on time that we became aware of later than we should have. In the future, I would
suggest a team to make going over all deadlines at the end of every team meeting a
priority. A second area of struggle was in task management of the final report
compilation. Overall, I feel our team did very well in the management of tasks, however,
we got caught up in our designs final iteration and did not pay enough attention to the
final report compilation as would have been ideal. In the end, the report was completed
well within deadline. In the future, I will try to stay focused on the whole project and not
let any one aspect of a project consume all of the team’s efforts.
I believe Group 11 was very successful in all individual and team efforts. All team
members got along very well. Furthermore, it is under my impression that team
members enjoyed the time spent with each other and not just the work being completed.
This was shown through the CATME results indicating a high average group team
rating. I believe all members of my team benefited from the experiences in MECH202
and will be better rounded individuals in real-world engineering applications for it.

120
CATME Results – Eric Lufkin 1

121

122

123

124

125

126

127

128

129

130

131

132
Reflection – Kylie Hardisty
Contributing to the Team’s Work:
I rated myself in second grouping for the survey 2 (taken at the end of march),
and survey 3 which was taken at the end of April. By teammates on the other hand
rated me in the third category for both the surveys as well. My teams average rating
was in the second grouping in which I thought I should have been. I gave myself this
rating because I completed my share of given assignments in a timely manner and at a
high quality. Though, there were a couple meetings I couldn’t make due to sickness or
personal issues; therefore, I do understand why I was rated lower than I rated myself.
To improve for future group projects, I should offer my help to my teammates whenever
possible and make sure I am helping adequately for all portions of the project as well as
put an extra amount of effort in if I am not able to make a meeting.
Interacting with Teammates:
For this section how I rated myself in the top grouping for both the second and
third surveys, but my team rated me in the second grouping on the second survey and
the third grouping in the third survey. This result was surprising to me because I
personally thought our team was very strong when it came to communicating what
needed to be finished, how things should be formatted and things such as that, so to
see that my team thought my interactions got worse over the course of this project was
shocking. Our average rating for both the surveys though where in the second grouping.
To improve I should act more enthusiasm about working with my team and get more
input from my team members when I am not 100% sure about something, as well as,
being more open to letting a team member help when it is necessary.
Keeping the Team on Track:
These results were the same for both survey 2 and 3. I rated myself in the top
category, my team rated me in the third category, and my teams average was in the
second category. This I agree with because there were occasions when I would get off
track or cause my group to have tangent conversations. The average rating of me and
my team was one step above that which also makes sense because while we all got
work done we had a good time together and would joke around; therefore, weren’t done
to business the entire time, but we always made use to get done what we had planned
to do. To improve in this area, I should stay aware of where we are in our overall
progress and make sure we are on track more often if we fall behind schedule.
Expecting Quality:
For both the second and third survey I rated myself in top grouping. I was rated in
the third grouping in the survey taken in March and in the second grouping in the most
recent survey. I am proud of this result because it shows that my teammates noticed a
positive change in my attitude about the standard of work I knew we could produce.

133
Having Related Knowledge, Skills, and Abilities:
This section also showed an increase of how my teammates rated be from the
second to third survey. For both the March and April survey I rated myself in the second
category. My teammates rated me in the third category in the March survey, but I was
rated in the second category in the April survey. I am very proud of this because it was
one of the most important areas I wanted to work on that I talked about in my reflection
after project 1, so the fact that my group saw a drastic enough change to rate me one
grouping higher is very satisfying to know.

134
CATME Results – Kylie Hardisty 1

135

136

137

138

139

140

141

142

143

144

145

146
Reflection – Will van Noordt
Our team worked incredibly well together on this project, and we are proud of the
result. Our device worked precisely as intended every time it needed to with only one
exception.
It was a privilege to work so comprehensively with this team. I believe our
strengths complimented each other well. Eric’s technical skills and quick
troubleshooting, Ray’s leadership, organization, and design, Kylie’s motivation and
creativity, and my analyzing skills all worked to create something that our team can be
extraordinarily proud of.
As well as the project went, there were still lessons learned, the main lesson
being that it is never too early to start prototyping. One of the only reasons the device
worked so reliably as it did was that we started early and could almost immediately see
the flaws in our initial design. Six iterations later, the kinks had been worked out and our
device functioned well.
Another important lesson I learned was that design projects are far easier and
run much smoother when all team members trust in each other’s abilities. If this is not
the case, then a situation can arise wherein each member is trying to check the other
members’ work constantly, and this process can be time-consuming. The fact that we
were able to trust in each other’s work and be held accountable to each other meant
that design changes were able to happen much faster than if this were not the case.
One of our main issues as a group was the fact that we did not exhaustively
document our work neatly. Though we did document everything, we did not do so in a
manner that was conducive to being able to write the report quickly, and so we have
been forced to relegate ourselves to the darkest corners of our backpacks and folders to
find what we need to compile. Though this was not the worst possible issue we could
have faced, it certainly will help us to be more careful next time.
Overall, I was glad to be a part of this particular team and, given the opportunity
to participate in this project again, I would not hesitate to work with them again.

147
CATME Results – Will van Noordt 1

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149

150

151

152

153

154

155

156

157

158

159
Failure Analysis
CSU MECH 202
Group 11
Failure Analysis……………………...........[160]

160
Failure Analysis
On competition day, we were able to beat two opposing teams and were beaten
by our third opponent. Our device functioned as intended in every way, however, a
situation arose that we had overlooked in our design process. Although, our ramps were
able to wedge themselves under our opponent, successfully keeping us in the track,
and our device was able to push the opposing team with ease, our opponent became
wedged between the track walls. When this occurred, both devices came to a standstill.
Our opponent was faster than us, and although we were able to push them, we had not
made it around the halfway point before our device was brought to a halt.
A possibly solution to this situation would be to increase our device speed by
incorporating a different motor, changing the diameter of the drive wheels, or simply
running our drive wheels off the inner radius of the track. When the devices came to a
stop, we were approximately half a foot from crossing the half way point. With more
speed, we would have contacted our opponent further down the track than we did and,
although we still may have become wedged with our opponent, we may have crossed
the half way point before this occurred.
A more comprehensive solution to this situation would be to design our device
with a smoother, wall-like surface of contact for opposing vehicles. With less to get
caught on in the front of our device, we may have been able to shed are opponent
without being wedged between them and the track walls. Although this may seem to be
a simple solution to the problem, it may have been challenging to design such a device
geometry while staying within the size constraints of the project.
Based on the three opponents we face on competition day, our device was able
to successfully expand to the track walls, deploy ramps, wedge its ramps under
opponents, and push opponents, consistently. We did not encounter any opponents that
were able to get underneath our ramps and drive our device out of the tracks or any
opponents that were able to impact with enough force to torque us out of position and
hinder our ability to achieve forward gain. If we were able to incorporate a design that
could successfully restrain opponents from becoming wedged between our devices
front surface and the track walls, we may have progressed much further in the
competition.

161
References
CSU MECH 202
Group 11
References………………………...........[162]

162
References
"Friction and Friction Coefficients." The Engineering ToolBox. N.p., n.d. Web. 01 May 2017.
<http://www.engineeringtoolbox.com/friction-coefficients-d_778.html>.
Nextrox. "Nextrox Mini 12V DC 60 RPM." Amazon. N.p., n.d. Web. 01 May 2017.
<https://www.amazon.com/Nextrox-Mini-Torque-Electric-
Motor/dp/B00BX54O8A/ref=sr_1_1?ie=UTF8&qid=1493509080&sr=8-
1&keywords=nextrox%2Bmini%2B12v%2Bdc%2B60%2Brpm%2Bhigh%2Btorque%2B
gear%2Bbox%2Belectric%2Bmoto>.

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Appendix
CSU MECH 202
Group 11
Technical Drawings……………...............[164]

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MECH202 Engineering Design Project Report

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MECH202 Engineering Design Project Report