Preliminary Detailed Design
Team Vision for Preliminary Detailed Design Phase
Updated Project ObjectiveCreate a wheelchair attachment that provides user independence when throwing and catching.
Updated Items from Phase IIhere here
Changed Engineering Requirements Phase 3
- ER31 Motor Battery
- ER32 Motor Lifespan
- ER33 Motor Torque
- ER34 Motor RPM
- No customer requirements changed from Phase 2 to Phase 3
Critical ParametersCritical Parameters are those requirements which are crucial to the design. These parameters ensure that we are fulfilling the Customer and Engineering requirements in a feasible way.
- Customer Requirement: Throw a ball with some mass some distance
- Ball’s mass range: 0.025- 0.132 kg
- Distance thrown: 30 feet == 10 m
- Exit velocity required: at most 16 m/s
- Released energy required: 2- 13 joules
- Stored energy required: 2- 13 joules
- Energy storage method will be through a spring
Benchmarking of Old Overcomer
|Pros of Old Catch/Throw Device||Cons of Old Catch/Throw Device|
|Pros of Old Striking Device||Cons of Old Striking Device|
Catching Module Design
The images below show how the throwing and catching systems will interact. Picture not to scale, only for design concept.
- Proposed Net: Franklin Sports 50" Sleeve
- Material: Durable polyester
- Between the top net and the middle net, the net will be taught and reinforced by clips on the side of the hoop.
- Between the middle net and the bottom net, the net will be looser to allow for distribution of energy from the projectile and reinforced by clips on the side of the hoop.
- Flap with hinge and spring at the bottom of the bottom hoop to slow down projectile in order to transfer properly.
- Net will attach to frame using clips.
Catching Device Parameters
Test 1: A 0.15 meter diameter ball and a net with a diameter of 2.5 meters with a relatively loose connection on the top, extremely loose as ball passed through net.
Conclusion: The brim diameter was too high and the net needed to be more taught as the ball passed through the net
Test 2: A net with a diameter of 2.0 meters with a relatively loose connection on the top, a taught bottom of the net, but net remained loose throughout that path.
Conclusion: The brim diameter was still higher than it needed to be. Net was too loose until the bottom/taught part, the path needed to be more defined.
Test 3: Determined that the optimal diameter of brim was 1.5 meters. The more taught at the upper most hoop, increases in taught-ness as ball travels through the net with 2 levels of rings provides stable path for ball (tightest one towards the bottom).
Conclusion: The brim diameter is at the optimal level and the taught-ness of the hoop is in sync with the engineering requirements.
Projectile Energy Calculations
Benchmarking Attachment Methods
Throwing Module Design
Detailed CAD Design
Bill of Material (BOM)Catching Subsystem Preliminary BOM
The preliminary Bill of Materials document can be found here.
Efficiency Tracking/ Individual Contributions
- Continue to send regular messages to group about upcoming deliverables
- Hold one another accountable to complete interdependent tasks
- Come up with an action plan and clear deliverables for bigger tasks so we know exactly what we need to do going into it and don't waste time spinning our wheels
Design Review MaterialsInclude links to:
Plans for next phase
- The live version of the Phase IV Project Plan can be found here
- The Three Week Plan document can be found here