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Wayne Chen Gavin Wu Kyuho Cha Edward Chan PowerPoint PPT Presentation


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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.

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Wayne chen gavin wu kyuho cha edward chan

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


Wayne chen gavin wu kyuho cha edward chan

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)


Wayne chen gavin wu kyuho cha edward chan

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.


Wayne chen gavin wu kyuho cha edward chan

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

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Wayne chen gavin wu kyuho cha edward chan

System Overview

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Wayne chen gavin wu kyuho cha edward chan

System Overview

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Wayne chen gavin wu kyuho cha edward chan

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

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Wayne chen gavin wu kyuho cha edward chan

Mainboard

Butterfly

Motor control

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Wayne chen gavin wu kyuho cha edward chan

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


Wayne chen gavin wu kyuho cha edward chan

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.

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Wayne chen gavin wu kyuho cha edward chan

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

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Wayne chen gavin wu kyuho cha edward chan

Safety Components

  • Upper Body Harness/Seat belt

  • -Prevents user from falling forward.

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Wayne chen gavin wu kyuho cha edward chan

Safety Components

  • Leg Supports

  • - Keeps the leg in place so that the person is kept from sliding forward.

  • - Cushion for knee area support.

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Wayne chen gavin wu kyuho cha edward chan

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


Wayne chen gavin wu kyuho cha edward chan

Project Finances

  • Prototype Production Cost

  • Prototype Funding

Wighton Engineering Development Fund

  • Cover all prototype costs

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Wayne chen gavin wu kyuho cha edward chan

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.

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Wayne chen gavin wu kyuho cha edward chan

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)

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Wayne chen gavin wu kyuho cha edward chan

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.

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Wayne chen gavin wu kyuho cha edward chan

Timeline

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Wayne chen gavin wu kyuho cha edward chan

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

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Wayne chen gavin wu kyuho cha edward chan

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.

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Wayne chen gavin wu kyuho cha edward chan

Questions?

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Wayne chen gavin wu kyuho cha edward chan

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

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Wayne chen gavin wu kyuho cha edward chan

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

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Wayne chen gavin wu kyuho cha edward chan

Software: Main Function Flow Chart

  • Back

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Wayne chen gavin wu kyuho cha edward chan

Software: Timer ISR

  • Back

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Wayne chen gavin wu kyuho cha edward chan

Mainboard

  • Components

    • - Protection

    • - Fuses

    • - Voltage regulators

    • - 3.3V (butter) 5V (sensor)

    • - Debug

    • - LEDs

    • - Relay

    • - Actuator control

    • - Butterfly

    • - Sensor input

    • - Bottom tilt sensor

  • Back

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Wayne chen gavin wu kyuho cha edward chan

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

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Wayne chen gavin wu kyuho cha edward chan

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

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Wayne chen gavin wu kyuho cha edward chan

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

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Wayne chen gavin wu kyuho cha edward chan

Sensor Circuitry-1

  • Back

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Wayne chen gavin wu kyuho cha edward chan

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

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Wayne chen gavin wu kyuho cha edward chan

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

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Wayne chen gavin wu kyuho cha edward chan

Aluminum

  • Cheap

  • Easy to machine

  • Weather resistance

  • Low density compared to other metals

  • Back

- Density, 2.70 g·cm−3

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Wayne chen gavin wu kyuho cha edward chan

Fabrication

  • Out sourced fabrication

  • Precise fabrication

  • CNC, Milling machine, on site welding

  • Bought own materials

  • 1 1/4 inch square aluminum tubes.

  • Back

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Wayne chen gavin wu kyuho cha edward chan

Technical Drawings

  • Back

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Wayne chen gavin wu kyuho cha edward chan

Technical Drawings

  • Back

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Wayne chen gavin wu kyuho cha edward chan

Technical Drawings

  • Back

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Wayne chen gavin wu kyuho cha edward chan

Technical Drawings

  • Back

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