2. Movement Assist System
Concept Validation and Feasibility
Analysis of chosen design
Integration with Other Systems
Results and Conclusion

3. Concept Validation and Feasibility1 2
4 Main Concepts
Feasibility of Crank mechanism
Mechanical Advantage versus difficulty of integration
Chosen Concept 3 4

4. Comparison and Analysis of Designs
Evaluation of straight line crank mechanism
Showed that the device can provide a mechanical advantage due to crank arm
Main concerns and issues are due to actual construction  binding and sticking in joints of links and moving the crank around two end points of arc
Risk of trying to construct this crank versus the benefit resulted in going with regular crank arm
Gear Sets
Large mechanical advantage
Risks in cost and disengagement
Couldn’t find standard made planetary gear sets with the required footprint  too thick/large
Regular Crank directly coupled to shaft provides lowest risk and best design due to ease of integration and has the benefits of a good mechanical advantage

5. Analysis of Chosen Design
FBD of Model and EOM
Minimum Torque Required to move system uphill
Key Assumptions
Rolling without slip
Frictionless bearings
Lumped Masses
Torque input from user is constant through Φ
Required Torque to turn generator is lumped into 1 term, Tmotor, and is constant
Starts from Rest

6. Results With 1.5m Crank

7. Results with Hand on Wheel Rim

8. Conclusion of Movement Assist
Crank Design is feasible by itself and should be able to be achieved
Difficulty is in the user activation/disengagement and integration with other systems
Freewheel
Shaft attachment
Integration with braking and ratchet
Based on CR (component of lowest priority) we are putting this system on hold to focus on more critical systems = Hill holder, Gradual Aid, and Energy Recovery