Transcript Document
YES U CAN – ADAPTIVE CYCLING University of Delaware , Department of Biomedical & Mechanical Engineering, Newark, DE Team Members: Brendan Farrell, David Huegel, Shane Kelly, Zack Rogers, Laura van der Post Advisors : Dr. Steve Timmins & Dr. Jennifer Buckley
Drive System
Key Highlights:
- Two chains and a stepper motor drive the trike via a joystick
Introduction
Purpose:
Yes U Can is a non-profit organization that creates opportunities for those with physical disabilities to become more active.
Braking System
1. A balance bar attaches to all three brake cables (2 from back and 1 from front) -
1
st
chain:
Drive motor sprocket to cassette
2
nd
chain:
Cassette to the front sprocket
Customers:
1. V
ickie George
, CEO and President, is a quadriplegic and suffers from a degenerative form of Multiple Sclerosis
2. Wayne Hunter
, YUC engineering consultant, is working with us in developing the drive, braking, and steering systems 2. A linear actuator with a connected spring will be attached to the balance bar and will help in providing tension in the cables 3. Braking by default system: the brakes are always engaged unless the user provides input through the joystick - Goal is to allow a quadriplegic (who has no movement in her legs) to exercise
Figure 1: Mock-up of stepper drive motor connection Figure 2: Mock-up of drive system chain connections on the trike
Steering System
1. Utilizes a linear actuator to push and pull on a 3 inch lever arm located at the front of the trike 2. Features a 30 degree turning angle in each direction, which has been calculated to be safe and efficient 3. Clamps are used to connect the linear actuator to the frame of the bike with a clevis attaching to the steering rod
Figure 5: YUC – Adaptive Cycling team with Vickie George and Wayne Hunter
The Design
• The project scope is to prototype an electrically-driven tricycle that allows a quadriplegic to become more physically active •
The overall design encompasses the following:
• Linear actuator controlled braking and steering systems • Stepper motor drive system • Battery powered electrical system • Balance bar braking concept • Aluminum machined clamping systems • FES (Functional Electrical Stimulation) will act as the main drive system with the electrically-driven system serving as a backup
Figure 3: Model of the steering actuator system Figure 6: Model of the complete assembly with all systems incorporated
Metrics & Testing Plan
• FEA (Finite Element Analysis) – high factors of safety • Engineering calculations • Physical testing with team members and Vickie
Want/Need
Safety Affordability Comfort
Metric
Stopping distance Cost # of sharp objects
Evaulation Plan
Brake test Cost analysis Road testing Durability Time until components need replacement Calculation based on battery capacitance
Table 1: Wants & needs along with associated metrics and evaluation plans for testing
Figure 4: Model of the clevis attachment clamp to lever rod Figure 7: Model of the braking system with associated clamps and linear actuator Figure 8: Model of the balance bar concept which provides accurate tension in each brake cable
Electrical
1. Batteries – Four 12V 35Ah batteries will be used to power the bike 2. Proof of concept of electrically-driven systems is demonstrated with a toggle switch 3. A battery pack has been manufactured to store the heavy batteries on the back of the trike
Figure 9: Electrical setup for joystick control of drive stepper motor