Rollerblade Braking System

1. Rollerblade Braking System Design Team #11

2. Design Team #11 • Team Members: • Sean Milley • Jamie Zwicker • Jeffrey Aucoin • Dima Eshtaya • Team Supervisor: • Dr. Robert Bauer

3. Presentation Overview • Introduction • Existing Design • Design Requirements • Selected Design and Manufacturing • Engineering Calculations • Budget • Testing • Further Recommendations • Conclusion • Questions

4. Introduction Existing Design Proposed Design http://www.jacqdesign.com/img/blog/photos/RollerbladeCrossfire4D.jpg

5. Areas of Improvement http://www.skatescool.com/inline-skating/learn-how-to-t-stop-on-inline-skates/ • Balance and Stability • Difficulty/Technique • Pad Wear and Lifetime • Stopping Distance

6. Design Requirements Requirements of Proposed Design

7. Design Requirements • Removable • Support a 225lb user • Improved braking distance • Maintain mobility/stability • Increased lifetime • Serviceable • Weather Resistant

8. Selected Design Foot Support Wheel Frame and Assembly Brake Actuator and Application Control Unit

9. Foot Support • Ability to attach over existing footwear • Modified existing snowboard binding • Added third strap • Added additional padding and support

10. Wheel Frame • Housing for all components of the skate • ⅛” Aluminum welded to form channel • Dimensioned to incorporate range of shoe sizes

11. Wheel Assembly • Axles • All rotating pieces • Bearings • Wheels • Brake rotors

12. Braking Unit Brake Application Brake Actuator

13. Brake Application • Two Avid Juicy III hydraulic calipers • One actuating piston • Two custom made stainless steel disc brake rotors

14. Brake Actuator • DC Electric Motor • Planetary Gear Box • Power Screw • Slider Nut • Hydraulic Piston • Piston Plunger

15. Control Unit Handheld Controller Skate Circuit

16. Handheld Controller • Controls braking force • Wireless • Adapted slot car remote • Added rapid prototyped box • Inserted solid state circuitry

17. Handheld Circuit

18. Skate Unit • Receives remote input • XBee Transceiver • Acts as PID controller • ArduinoDuemilanov Microprocessor • Force sensor feedback • Controls motor • Pololu High Power Motor Controller • Speed and Direction • Generates brake force • Motor pushing piston

19. Skate Circuit

20. Arduino Microprocessor • Reads in PWM from XBee • Converts to percent • Reads in analog feedback from Force Sensor • Converts to percent • Calculates error • Implements Digital PID Control • Sends Motor Controller commands • speed and direction http://blog.makezine.com/arduino_duemilanove_redo.jpg

21. Engineering Calculations Brake Force Calculations Motor and Power Screw Torque Calculations Hydraulics Calculations

22. Brake Torque Calculations

23. Disk Brake Calculations

24. Output Force Power Screw Calculations Power Screw Specs http://www.roton.com/application_engineering.aspx Required Actuating Force = 78.5N

25. Hydraulic Calculations • One piston For two Calipers • Piston Displaces 1.75ml for a 1” stroke • Maximum Allowable Clearance = 1.4mm

26. Budget Initial Budget Final Cost

27. Initial Budget

28. Final Cost

29. Testing Slider Nut Testing Force Sensor Testing PID Tuning Initial and Final Brake Testing

30. Slider Nut Tests • Nylon nut striped at 2.48Nm • Motor Torque = 1.45Nm • Original nut stripped during application • Inserted brass threads in nut to rectify the issue

31. Force Sensor Tests and Calibration • Made testing apparatus • Loaded force sensor • No load • 20lb • 70lb • 120lb • Tested • Resistance (Multimeter) • Voltage Output (Oscilloscope) • Tuned circuit • Maximum Motor Output = Maximum Sensor Output

32. PID Tuning • Tuned mainly by Trial and Error • Tuned to: • Maximize • Speed • Response Time • Minimize • Steady-State Error • Oscillations • Transient Error

33. Braking Test 10 m 13 m Original Stopping Distance 10 m in 1.8 sec = 20km/hr

34. Stopping Distance Tests

35. Weighted (225lb) User Tests

36. Initial Testing Maximum speed: 30km/h Average stopping distance from 20km/h: 13m

37. Final Testing • Average stopping distance from 20km/h: 9.1m • Improved braking distance by 4.1m • Maximum speed: 27km/h

38. Requirements Met Requirement How it was met • Removable • Support a 225lb user • Improved braking distance • Maintain mobility/stability • Increased lifetime • Serviceable • Weather Resistant • Snowboard Binding • Weight Test • Braking Test • Wireless • Mountain Bike Brake Pads • Bolts and Snap Rings • Calking and Plexi-Glass

39. Further Recommendations Areas for Future Improvement

40. Further Recommendations • Brushless DC Motor • Faster Motor • Smaller Brake Calipers

41. Conclusion How It Works Final Product

42. How It Works • User pushes down on handheld remote • Varying the voltage to the XBee (0-3.3V) • XBee sends wireless signal • XBee receives signal in skate • Outputs PWM (0-3.3V)

43. How It Works (Continued) • Arduino reads in XBee signal and force sensor feedback • Coverts both to a percentage • Determines error • Implements digital PID control • Sends signal to the motor controller (4 Byte string) • Motor Controller receives data string • Operates motor • Force sensor feedbacks analog voltage to Arduino (0-5V)

44. Final Product

45. Special Thanks To: Shell Canada Cyclesmith The Binnacle Dr. Robert Bauer Dr. Ken Wilkie Jonathan MacDonald Albert Murphy Angus McPherson Mark MacDonald

46. Questions?