1 / 40

Wayne Chen Gavin Wu Kyuho Cha Edward Chan

Wayne Chen Gavin Wu Kyuho Cha Edward Chan. Overview. Background Motivation Our Solution System Overview Future Development Business Case Finances Final Thoughts. Background. Spinal Cord Injury (SCI) Study. In 2007, approximately 225,702 people suffer from SCI.

curt
Download Presentation

Wayne Chen Gavin Wu Kyuho Cha Edward Chan

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Wayne Chen Gavin Wu Kyuho Cha Edward Chan

  2. Overview • Background • Motivation • Our Solution • System Overview • Future Development • Business Case • Finances • Final Thoughts

  3. Background • Spinal Cord Injury (SCI) Study • In 2007, approximately 225,702 people suffer • from SCI • Estimated annual SCI is approximately 12,000 • new cases each year. • Types of Disability & Proportions • 34.1% incomplete tetraplegic (weak control • over upper & lower body muscles) • 23% are complete paraplegic (no control over • lower body movement) • 18.5% are incomplete paraplegic (weak lower • body movement)

  4. Design Motivation • Allow Better Blood Flow Circulation • Beneficial for the muscles and blood flow • Relieve pressure and stress from buttocks • area. • Height Control System • Allow user to have equal eye level • communication. • Increase range of height, ease of access to • shelf top, switches… etc.

  5. Our Solution • Innovative, Reliable & Cost Effective Device • A system that can be retrofitted on to existing • power wheelchair designs and be able to • transfer an user effortlessly from a sitting to a • standing position. • Goals • Safe and secure transfer for the user • Manual button controls for user 5

  6. System Overview 6

  7. System Overview 7

  8. Button Controls • Tactile switch buttons • -Up, Stop, Down, Memory • Up • -sitting to standing trasistion • Down • -standing to sitting transistion • Stop • -stop all transition • Memory • -memorizes the current position 8

  9. Mainboard Butterfly Motor control 9

  10. Tilt Sensor/Accelerometer • Bottom of the seat • Detects the angle between the frame and the seat. • Allows the micro-controller to monitor the position of the seat. 10

  11. Mechanical Design • Linear Actuators - Controls the bottom and top frame movement. • Light-weight Aluminum Frame - Allows minimum change to actual wheelchair. • Strong and secure foundation for • user. 11

  12. Trajectory of Motion • Final Position - 70 Degrees incline - Users have weak joints that does not allow for max movement • Customizable Trajectory - Movement range changes with the mounting position/size of the actuators 12

  13. Safety Components • Upper Body Harness/Seat belt • -Prevents user from falling forward. 13

  14. Safety Components • Leg Supports • - Keeps the leg in place so that the person is kept from sliding forward. • - Cushion for knee area support. 14

  15. Future Development • Actuator Control - Control both actuator at the same time. - Put a safety function to detect interference of actuator motion. • Enhanced Safety, Comfort & Appeal - Attach higher quality safety harness to improve comfort and safety. - Improve visual appeal and design of frame and components • User Interface - Sip –n-puff(ideal for quadriplegic people). • Customizable - Customize frame to fit the needs of various body type. - Use different size actuators to control the trajectory of the frame. 15

  16. Project Finances • Prototype Production Cost • Prototype Funding Wighton Engineering Development Fund • Cover all prototype costs 16

  17. Actual Costs • Product Cost • Fabrication costs were a major portion of our project budget. If mass • production occurs, partnership can be made with fabrication shop and may • be able to lower a large portion of the project costs. • Unused Parts • Extra and additional parts were sourced in for quick replacement if parts • are damaged along the testing phases. 17

  18. Competition • C500vs Series - High Cost $30,000 - $40,000 - Built as all-in-one unit - Able to select the features you want for customization • EasyStand Ovation Strap Stand - No mobility - Separate unit - Large and bulky (Robust) 18

  19. Business Opportunities • Possible Usage • Assist with standing process for people with weaker leg strength. • - Transfer the user to a position suitable for urination • Incentives - Not all disabled people have the same needs. - Minimize cost by reuse/upgrade existing wheelchair. - Could become a part of rehabilitation process. - Allow better blood flow to the legs - Decrease work load for nurses/doctors to stand a person up. 19

  20. Timeline 20

  21. Acknowledgements • GF Strong Rehabilitation Center • Ian Denison (Physiotherapist) • Charles Martin (Wheelchair Technician) • Peter Borwein • Patrick Leung • Jason Lee • Jamie Westell • Andrew Rawicz • Steve Whitmore • Carlo Menon 21

  22. Conclusion • Successful Completion of Goals • Scheduled Deadline • What We Learned • Mechanical system design and fabrication. • Technical knowledge of different components • Integration techniques of mechanical and electronic components. • - Team environment and management. 22

  23. Questions? 23

  24. Technical Information • Motor Controller • Software: Main Function Flow Chart • Software: Timer ISR • Main Board • AVR Butterfly • Tilt Sensor • Sensor Circuitry – 1 • Sensor Circuitry -2 • Max Weight Calculations • Aluminum • Fabrication • Technical Drawings 24

  25. Motor controller Vcc: 12V Logic one from butterfly : 3.3V β of the npn: 100 Ic =xxmA Ib = Ic/ β R1 = (3.3-0.7)/Ib R1 = (3.3-0.7)/Ib Relay Coil: 12V 75mA 160 ohms Absolute maximum for transistor: 200mA • Back 25

  26. Software: Main Function Flow Chart • Back 26

  27. Software: Timer ISR • Back 27

  28. Mainboard • Components • - Protection • - Fuses • - Voltage regulators • - 3.3V (butter) 5V (sensor) • - Debug • - LEDs • - Relay • - Actuator control • - Butterfly • - Sensor input • - Bottom tilt sensor • Back 28

  29. Butterfly • Operating voltage • - 2.7V to 5.5V (we chose 3.3V) • Supply current • - 2.3mA to 4mA • CPU speed • - 8MHz, factory set by software to 2MHz to save button battery life. • ADC • - 10-bit (0-3.3V ADC range) • - Changed reference voltage to 1.1 to increase ADC sensitivity • Timer • - 16-bit timer counter with 64 prescaler • - Timer interrupt is set to 0.08s • Back 29

  30. Butterfly • I/O • - PortB, PortD, JTAG/PortF (ADC) • - PortB used for button control and bottom actuator control • - PortD used for LEDs to output current stage for debugging purposes, PortD also used for controlling back actuator • Temperature range • - (-40C to 85C) • LCD • - PortD, turned off to avoid conflict between output function and LCD display • Absolute maximum ratings • - Operating voltage, 6.0V • - DC current per I/O pin 40.0mA • - DC current Vcc and GND pins 200.0mA • Back 30

  31. Tilt sensor/Accelerometer • Operating voltage • - 4.75V to 5.25V • Single Axis • - Z axis • Sensitivity • - 750mV/g • - 2.5g sensing range • Temperature range • - (- 40C) to (105C) • Supply current • - 1.1 to 3mA • Self protection mechanism • - 2kV ESD protection circuitry • Back 31

  32. Sensor Circuitry-1 • Back 32

  33. Sensor Circuitry-2 Rf = 2.2 Kohm Ra = 1 Kohm R1 = 1 Kohm S = 1 Rs = 2.2 Kohm Rx = 3.7 Kohm Ry = 1.3 Kohm • Back 33

  34. Max User Weight Force at Position A = (45.89 Kg + 9.07 Kg)* 9.81m/s^2 = 539.16 N Moment from Weight at Position A = 539.16N * 82 = 44210.92 Limitation Force at Position B = 44210.92/30 = 1473.70 Max Weight at Position B = 150.22 Kg • Back 34

  35. Aluminum • Cheap • Easy to machine • Weather resistance • Low density compared to other metals • Back - Density, 2.70 g·cm−3 35

  36. Fabrication • Out sourced fabrication • Precise fabrication • CNC, Milling machine, on site welding • Bought own materials • 1 1/4 inch square aluminum tubes. • Back 36

  37. Technical Drawings • Back 37

  38. Technical Drawings • Back 38

  39. Technical Drawings • Back 39

  40. Technical Drawings • Back 40

More Related