Team Vision for Detailed Design Phase
- Create revisions of cart design to do the following: Balance weight front to back, reduce number of peg holes, protect the motor from potentially rolling off of its designated shelf, enable engine airflow, allow the user to more easily adjust the position of shelves
- Complete FEA on cart design
- Create a mechanical drawing package for cart design
- Create manufacturing and assembly plans for cart design
- Determine what components the team needs to purchase or make in order to use the dynamometer for testing
- Finalize test plans
- Create a full schematic for the test bench
- Update use cases for wireless program
- Create detailed models for GUI
- Test wireless between dyno control room and dyno room
Dynamometer RequirementsThe KGCOE dynamometer is equipped with a platform to mount the devices to be tested along with the appropriate ventilation to remove engine exhaust.
The following items will be collected from previous Hot Wheelz dynamometer tests and will be used during testing of our own project:
- Dynamometer sprocket - to connect to chain
- Dynamometer sprocket face plate – to mount sprocket to dyno
- Motor sprocket – pto connect to chain
- Chain - power transmission
- Chain tensioner – reduce slack in chain
- Alignment bar – In dyno room, used to ensure proper chain alignment
- Motor shaft keyway – power transmission
Revision B: 3D Model
The figures below show Rev B of the cart from the PDDR
Feasibility testing and updates
1. Balance of Weight- Front to Back
-Center of Mass in x and y calculated from ground and handle (origin). With values below and calculations shown, a critical angle for tipping and a critical force to lift cart was found.
2. Reduce number of peg holes
3. Motor shelf brake
-McMaster clasp found
4. Engine airflow
-Pattern of slots created to increase airflow ability.
5. New shelf attachment method
-Wall mount shelving chosen
FEA testing Results:
|Test Bench item to be tested||Results||Important Values|
|Motor Shelf||Apply engine mass at center of plate and have mounting at from and rear side as if held by hand or table on one side and cart on other||The engine is the heaviest component which will need to move. Most of the weight will be supported by the dyno table but FEA will test for the transition|
|Main Base Pegboard||Unnecessary now; cart will be supporting the weight of everything now instead of the pegboard.||Load capacity 2000 lbs.|
|Main supporting walls||Weights are supported by new shelf supports||Weight capacity 220 lbs per shelf*|
Shelf Support Feasibility
Concern: Shelf runner pulling itself off of center divider
-Divider is ½” thick and screws being used have a tensile strength of 170,000 psi
-Calculated pullout strength is 320lbs at the screw using ¼-20
Revision C: 3D model-After making the model changes described above Cart Rev C was made.
Revision D: 3D model modifications
Original- 1/2" thick aluminum
Analysis- Simulation completed on largest shelf with Balsa wood characteristics (similar to particle board) FOS of 4
To be completed by start of next semester:
1. Confirm drawing package is up to date
2. Order/ purchase material for manufacturing
3. Order cart to begin build
Drawings, Schematics, Flow Charts, Simulations
Mechanical Drawing Package
Working Drawing Package can be found here
Cart Manufacturing Plans
- Working plans will be attached here.
- Note: Most components will be purchased and merely trimmed to size to fit our needs
Test Bench Electrical System
Finished GUI ModelsFor additional GUI mockups, see the PDDR page.
The Flask microframework is being used in conjunction with the SQLalchemy database. All the GUI pages have been linked to each other in Flask. The database has beeen filled with dummy data. Information gathered from the HTML pages when the user hits submit can be used to add new CAN entries, edit entries, and delete them as well as modifying other data.
- Finish implementing the functionality of each HTML page in relation to the database
- Implement the functionality for a downloadable log file and user control of the logging
- Enable data validation on all pages
- Prototyping: Use the rPi to connect to a live CAN bus and design a decoding program to pass on the data to a UDP socket program which will interface with the front end
- Prototype sensor interfacing
- Calibrate sensors
Prototyping PlansPrototyping plans for the sensor interfacing can be found here
Calibration PlansCalibration Plans for the complete sensor system can be found here
Bill of Materials (BOM)
The full bill of materials can be found here. The team's budget can be found here. The biggest changes to the budget this phase were the addition of extra components to help secure the motor shelf, shelf runners and arms, and a cart purchased rather than fully fabricated ourselves.
Test PlansOur test plan tracking document can be accessed here
Test plan S1: Distance from system for successful retrieval of data via wireless telemetry has been completed and passed. During testing it was also confirmed that the wireless system will operate through the dynamometer walls.
Risk AssessmentOur updated risk assessment can be accessed here
Plans for next phase
Our team plans to make any necessary changes to design following the Detailed Design Review and then continue purchasing components to allow for build tasks to be started in January at the beginning of MSD II. We plan to build the different components of the cart (walls, shelves, etc.) and begin prototyping electrical circuits. Additionally, we plan to continue programming the raspberry pi, implement the GUI, and write a program for the CANbus to transmit information to the GUI. See below for a detailed schedule for MSD II.