Lecture Notes on ASME Design Competition | MET 495, Study Guides, Projects, Research of Mechanical Engineering

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PROPOSAL FOR

ASME Design Competition

By

Kevin Sykes, Mathew Brooks

Table of Contents

Engineering Merit:

The technical merit of this project is focused in several different areas. The energy

consumption of the vehicle is one of the areas where calculations were performed. A motor was

selected and calculations were performed to determine the minimal amount of energy to run the

motor. This was done to find the minimal battery size. The gear reductions for the motors were

also a focal point for calculations to insure the vehicle would have enough power with a full load

to climb over the 2x4 and 4x4’s in the course and these were done using equations from the

Mechanical Design Textbook by Mott. Stress analyses on components of the design were

conducted on the axles and the stresses on the chassis to insure they would not fail.

Success Criteria:

Success of the project depends on several different parts. First the vehicle must be able to

meet all AMSE Design Competition guidelines. The device must also be built in time for the

competition. The project must also show engineering analysis which can backup our design

choice.

The success criteria is listed as follows:

The winning device will have the highest score S where:

S = Σ (R*t) +1000P - W - A - 1000T – 5s

R = designated rock score

t = target multiplier

W = Weight of the vehicle in grams

A = milliamp-hours available to the device according to the battery labels

T = Times device touches border tape

s = seconds to complete task, maximum 240

P = bonus for parking vehicle at end of task (1 = parked, 0 = not parked)

METHODS Approach:

This project was conceived, analyzed and designed by Kevin Sykes and Mathew Brooks

at CWU. The device was developed based upon the knowledge gained from engineering courses,

knowledge of robotics, and financial constraints.

Description:

The design chosen was a vehicle which uses a skid-steer track system to allow for

maximum stability when climbing obstacles; the tracks were also chosen to prevent any high-

centering. The device chosen to gather the rocks is a simple swinging arm which uses a single

servo that sweeps the rocks into a bucket located between the two tracks. Once the rocks are

swept into the bucket the arm will close thus sealing the bucket causing the rocks not to fall out

when the vehicle is travelling over obstacles. When the vehicle has reached the assigned drop-

off point the arm will swing open and the back of the bucket will rise causing the rocks to fall

out. The arm will then close and the rocks will be pushed into the target area. The bucket

mechanism will operate using single servo mounted above which is connected to a line that is

attached to the back of the bucket. The bucket will be hinged in the front, and as the rear of the

bucket is lifted the bucket will rotate about the hinge points in the front.

The device itself, with all components, will fit within a 370x165x165mm box; it will

follow all the guidelines provided by the ASME design competition.

See appendix B for drawings.

Risk Analyses:

The risks involved in this project include the possibility that the vehicle will not be completed in

time for the competition on April 18th, 2009. Since Matt and Kevin have very limiting

knowledge on the subject of radio controlled cars there is a possibility that this device may not

function.

Benchmark:

The device will be scored and compared with the other vehicles at the contest. This will give a

good basis to how the design compares with the other contestants.

Design & Construction Approach

The analysis of the device was done by both Matt and Kevin using information out of

Mott’s Strength of Materials textbook and Mark’s Machinery Handbook. The analysis was found

for different aspects of the vehicle which were most crucial in the design. Not all the parts of the

design were analyzed due to the amount of fabrication needed to be done in order to complete

the design before the ASME Design Competition.

Design

Chassis Design (Matt Brooks & Kevin Sykes)

The design for the chassis is designed to make the device as rigid and as light as possible.

The design was chosen to exert most of the forces on the device onto the side supports of the

chassis. This was done to create more space in the middle of the device to allow for more room

for the bucket to operate. The space between the two side supports is designed to be held in place

with different sections of aluminum. These aluminum sections will hold the side supports rigid

and also provide a place to put the motors, servos, and battery, receiver, and speed controllers.

Please refer to Appendix B for all device and assembly drawings.

Wheel/Tread Design (Matt Brooks)

The tread and wheel design is designed to move the device easily over the 2x4’s. The

reason to use treads as opposed to wheels was to move the vehicle over the barriers while not

flipping over. The 100 mm wheel design in the back was designed to increase the torque and to

increase the contact area for the wheel and the tread. The 100 mm wheels on the front are

designed to be able to slide up and down the side support in order to increase and decrease the

tension in the device.

Scoop Design (Kevin Sykes)

The rock scoop is used to sweep the rocks into the bucket and to keep them secure while

the device is in motion. The rock scoop is curve towards the bucket to help guide the rocks into

the bucket. A servo attached rigidly to the chassis will be geared to run a shaft which will in turn

move the rock scoop. The scoop will swing 90 degrees and sit flush with the bucket. The scoop

will then be held in the closed position while the vehicle is in motion to prevent the rocks from

falling out of the bucket.

Bucket Design (Kevin Sykes)

The bucket is designed to be movable in the z axis but rigid in the y axis. The front of the

bucket is supported with spring-loaded suspension which is rigid at the chassis and pin connected

to the front of the bucket. The back of the bucket has an open area where a rigid L-shaped

support is inserted. When going over the 2x4’s, the bucket will be able to move up and out of the

way of the 2x4. When it is time to dump the rocks which have been gathered, a servo with a

BUDGET

A parts and budget list can be seen in appendix A. The budget for this vehicle is estimated to

cost of $548.37 and this includes all the cost to buy the parts, labor, and manufacturing the

chassis. The estimated time to complete this project is around 118.5 hours. Some of the

assemblies will require machining and fabrication. We will divide fabrication between the two of

us for equal amount of work. The cost of this project is supported by Kevin Sykes and Mathew

Brooks.

SCHEDULE

The schedule for this project is constrained by the MET 495 course. Using the first

quarter schedule as a template, the next two quarter-schedules have been proposed. This project

will be completed by the last week of the third quarter. Please refer to Appendix C for the

schedule listings.

Individual tasks include construction completion of the chassis, bucket assembly,

sweeping mechanism, energy analysis of the system, and stress analysis of critical parts.

All of the tasks have identifiers that allow the reader to see when they are active, time to

complete the project, and task completion dates.

Deliverables include completion on the project according to the set time table, and to

fulfill the requirements set out by the ASME Design Contest.

CONCLUSION

A device/model will be conceived, analyzed and designed that meets the function requirements

presented. Parts have been specified, sourced and budgeted for acquisition. With this

information the device/model is ready to be created.

ACKNOWLEDGEMENTS

To date the majority of the design has been conceived by Kevin & Matt. There has been some

support from the students within the MET department on improvements and alternative ways of

achieving our goals. Thanks to Daniel Brown for help with the CNC Machine and Matt ___.

APPENDIX A – Parts & Budget

ITEM

Labor Cost

• Introduction……………………………………………………………..………………….. Section Page
• Methods…………………………………………………………………..…………………
• Construction……………………………………………………………..………………….
• Budget………………………………………………………………….………………….
• Schedule……………………………………………………………….………………..…
• Expertise and Resources…………………………………………………….…………….
• Conclusion…………………………………………………………………………………
• Acknowledgements……………………………………………………………………..…
• Appendix………………………………………………………………………..…………
• 1 Batteries Buy $25.00 1 $25. ID ITEM Description Item Source Price Quantity Subtotals
• 2 Battery Charger Buy $20.00 1 $20.
• 3 Motors Buy $30.00 2 $60.
• 4 Wheels Build $5.00 4 $20.
• 5 Wheel Tracks Buy $20.00 2 $40.
• 6 Body Build $20.00 1 $20.
• 7 Servos Buy/Scavenge $20.00 2 $40.
• 8 Radio Transmitter Buy $50.00 1 $50.
• 9 Radio Receiver Buy $20.00 1 $20.
• 10 Radio Transmitter Buy $35.00 1 $35.
• 11 Bearings Buy/Scavenge $2.00 10 $20.
• 12 Belts Buy $3.00 1 $3.
• 13 Sheaves/Pulleys Make $5.00 2 $10.
• 14 Speed Controller Buy $20.00 2 $40.
• 15 Gears Buy/Scavenge $5.00 2 $10.
• Total $413.
• Wheels 4 $50 $ Item to Construct Time Rate/hr Subtotal
• Side Support 2 $50 $
• Axles 1 $50 $
• Transmitter Case 1 $50 $
• Sheaves/Pulleys 4 $50 $

APPENDIX B – Device Drawings

5 Part Construction 5a Buy axels 1 0 1-Mar 5b Buy motors 1 0 1-Mar 5c Buy Transmission 1 0 1-Mar 5d Buy batteries 1 0 1-Mar 5e Buy wheels 1 0 1-Mar 5f Buy tracks 1 3 0 1-Mar 5g Make Bucket 4 0 1-Mar 5h Make Chassis 8 0 1-Mar 5i Buy Gears 1 0 1-Mar 5j Buy receiver 1 0 1-Mar 5k Buy servo 1 0 1-Mar 5l Build drive shaft 2 0 1-Mar 5m Build suspension arms 2 0 1-Mar 5n Bucket construction 4 0 1-Mar Subtotal: 23 6 Device Construct 6a Chassis Built 20 0

Mar 6b Take Dev Pictures 1 0

Mar 6c Update Website 2 0

Mar subtotal: 23 0 Duration TASK: Description Est. Kevin's Hrs Matt's Hr's January Februar y Marc h April May June ID (hrs) (hrs) (hrs) 7 Device Evaluation 7a List Parameters 1 0

Apr 7b Design Test&Scope 1 0

Apr 7c Test Plan* 1 0

Apr 7d Perform Evaluation 5 0

Apr 7e Take Testing Pics 1 0

Apr 7f Update Website 2 0

Apr subtotal: 11 0 8 Design Competition 8a Design Competition 5 17-

Apr 9 495 Deliverables 9a Get Report Guide 1 0 1-May 9b Make Rep Outline 1 0 7-May 9c Write Report 1 0

May 9d Make Slide Outline 1 0

May 9e Create Presentation 1 0

May 9f Make CD Deliv. List 1 0

May 9g Write 495 CD parts 1 0

May 9h Update Website 1 0

Jun 9i Project CD* 1 0

Jun subtotal: 9 0