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/Rollerbl
adeCrossfire4D.jpg
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Areas of Improvement

• Balance and Stability
• Difficulty/Technique
• Pad Wear and Lifetime
• Stopping Distance

http//www.skatescool.com/inline-skating/learn-how
-to-t-stop-on-inline-skates/
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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

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Wheel Frame

• Housing for all components of the skate
• ? Aluminum welded to form channel
• Dimensioned to incorporate range of shoe sizes

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Wheel Assembly

• Axles
• All rotating pieces
• Bearings
• Wheels
• Brake rotors

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Braking Unit

• Brake Application
• Brake Actuator

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Brake Application

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

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Brake Actuator

• DC Electric Motor
• Planetary Gear Box
• Power Screw
• Slider Nut
• Hydraulic Piston
• Piston Plunger

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Control Unit

• Handheld Controller
• Skate Circuit

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Handheld Controller

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

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Handheld Circuit
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Skate Unit

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

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Skate Circuit
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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
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Engineering Calculations

• Brake Force Calculations
• Motor and Power Screw Torque Calculations
• Hydraulics Calculations

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Brake Torque Calculations






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Disk Brake Calculations
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Power Screw Calculations

• Power Screw Specs

Output rpm Output Rev/s Torque Nm Torque inlb Thread Type
444 7.4 1.454 12.869 ¼-20 LH
http//www.roton.com/application_engineering.aspx

• Output Force

Force Lb Force N
161.9 720.1
Required Actuating Force 78.5N
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Hydraulic Calculations

• One piston For two Calipers
• Piston Displaces 1.75ml for a 1 stroke
• Maximum Allowable Clearance 1.4mm

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Budget

• Initial Budget
• Final Cost

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Initial Budget
1 Braking, 1 Non-braking 1 Braking, 1 Non-braking 1 Braking, 1 Non-braking 1 Braking, 1 Non-braking 1 Braking, 1 Non-braking 1 Braking, 1 Non-braking
  Description Qty Unit Price Total Price Totals
Roller Blade Prototype 1 100.00 100.00  
  Attachment screws and bolts 1 20.00 20.00  
  ratchet straps 6 9.99 59.94  
  strap buckle 6 12.99 77.94  
  axle rod 1 6.50 6.50  
square channel 1 20.00 20.00  
  plastic foot support 2 45.00 90.00  
8 x 90mm wheels with bearings 1 79.99 79.99  
Section Sub-Total         454.37
Braking Planetary gear and power screw motor 1 35.55 35.55  
  Rotor 2 10.00 20.00  
  Hydraulic brake caliper with lever controlled piston 1 150.00 150.00  
  Hydraulic brake caliper 1 80.00 80.00  
  Hydraulic fluid 1 20.00 20.00  
Section Sub-Total         305.55
Wireless Controller Transmitter 1 40.00 40.00  
  Receiver 1 40.00 40.00  
  Micro Controller 1 108.00 108.00  
  Motor Controller 1 50.00 50.00  
Section Sub-Total         238.00
Safety Equipment Helmet 1 29.99 29.99  
  Mouth guard 1 10.00 10.00  
Section Sub-Total         39.99
Power source battery pack and charger for actuator motor 1 23.99 23.99  
  16 AA batteries for wireless controller 1 20.00 20.00  
Section Sub-Total         43.99
Total Summary sub total       1,081.90
  13 tax       140.65
  10 miscellaneous       108.19
  final total       1,330.74
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Final Cost
Final Cost Final Cost Final Cost Final Cost Final Cost Final Cost
  Description Qty Unit Price Total Price Totals
Rollerblade Wheels 1 50.84 50.84  
  Wheel Frame, Axel Rod, Steel and Aluminum 1 58.76 58.76  
  Bolts and Fasteners 1 8.77 8.77  
  5/16" Snap Rings 1 12.20 12.20  
  Electronics Isolator Pad 1 9.61 9.61  
  Acetone 1 7.79 7.79  
Section Sub-Total         147.97
Braking Planetary Gear Motor W/RS-370 1 50.31 50.31  
  Motor 2 (Brushless) 1 24.84 24.84  
  Motor 3 1 67.77 67.77  
  Motor 4 1 7.90 7.90  
  Avid Juicy 3 Hydraulic Brake Caliper Kit 2 96.05 192.10  
  3/16" Hydraulic T-Fitting 1 7.16 7.16  
  Hydraulic fluid 1 7.90 7.90  
Section Sub-Total         357.98
Wireless Controller SFE Maxstream 1mW XBEE Transciever w/ SFE XBee Explorer Regulated Base 2 43.61 87.22  
  Arduino Duemilanove USB Microcontroller 1 37.06 37.06  
  Pololu High Power Motor Controller 9A 1 122.31 122.31  
  Miscellaneous Electrical Components 1 143.56 143.56  
  Variable Resistors 3 8.28 24.84  
  Force Sensor 1 130.05 130.05  
  Hand Controller Frame 1 47.22 47.22  
Section Sub-Total         592.26
Power Sources 9V Batteries 12 3.81 45.75  
  7.2V Battery Pack w/ Charger 1 22.59 22.59  
Section Sub-Total         68.34
Foot Support Snowboard Bindings 1 55.37 55.37  
  Ratchet Straps and Buckles 1 13.57 13.57  
  Boot Wrapping 1 39.55 39.55  
  Leg Padding 1 6.59 6.59  
Section Sub-Total         115.08
Total Summary Grand Total       1,281.63
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Testing

• Slider Nut Testing
• Force Sensor Testing
• PID Tuning
• Initial and Final Brake Testing

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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

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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

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PID Tuning

• Tuned mainly by Trial and Error
• Tuned to
• Maximize
• Speed
• Response Time
• Minimize
• Steady-State Error
• Oscillations
• Transient Error

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Braking Test
10 m
13 m
Original Stopping Distance
10 m in 1.8 sec 20km/hr
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Stopping Distance Tests
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Weighted (225lb) User Tests
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Initial Testing

• Maximum speed 30km/h
• Average stopping distance from 20km/h 13m

Stopping Distances from 20km/h Stopping Distances from 20km/h Stopping Distances from 20km/h Stopping Distances from 20km/h Stopping Distances from 20km/h
  Jamie Dima Jeff Sean
Trial 1 13.2m 14.6m 14.5m 12.6m
Trial 2 13.1m 13.9m 13.6m 12.9m
Trial 3 12.5m 12.9m 13.5m 12.6m
Trial 4 12.2m 13.3m 12.5m 12.5m
Average 12.8m 13.7m 13.5m 12.7m
Average Group Stopping Distance Average Group Stopping Distance Average Group Stopping Distance Average Group Stopping Distance 13.2m
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Final Testing

• Average stopping distance from 20km/h 9.1m
• Improved braking distance by 4.1m
• Maximum speed 27km/h

Stopping Distances from 20km/h Stopping Distances from 20km/h Stopping Distances from 20km/h Stopping Distances from 20km/h Stopping Distances from 20km/h
  Jamie Dima Jeff Sean
Trial 1 10.2m 10.6m 9.8m 9.8m
Trial 2 8.7m 10.9m 8.3m 7.8m
Trial 3 8.4m 10.5m 11.2m 8.4m
Trial 4 6.7m 9.3m 7.5m 7.1m
Average 8.5m 10.3m 9.2m 8.3m
Average Group Stopping Distance Average Group Stopping Distance Average Group Stopping Distance Average Group Stopping Distance 9.1m
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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

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Further Recommendations

• Areas for Future Improvement

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Further Recommendations

• Brushless DC Motor
• Faster Motor
• Smaller Brake Calipers

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Conclusion

• How It Works
• Final Product

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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)

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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)

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Final Product
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Special Thanks To

• Shell Canada
• Cyclesmith
• The Binnacle
• Dr. Robert Bauer
• Dr. Ken Wilkie
• Jonathan MacDonald
• Albert Murphy
• Angus McPherson
• Mark MacDonald

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Questions?