TEAM 3: ACHIEVING MOBILITY

Matt Last, Rob VanderVennen, Matt Rozema, Dan Evans

Outline Project Definition Design Final Product Conclusions Questions

Introduction Isaac Postma Spinal Muscular Atrophy Physical Limitations Current Transportation

Project Definition Design an electric wheelchair that the individual can

control while lying down Two operational modes:

Manual (attendant-controlled) Electric (user-controlled)

Touchpad controlled driving system LED system indicating possible directions One camera and monitor for user vision

Major Design Decisions Motor control hardware topology Feedback type User interface Power regulation safety Structure affected by other component designs Customer requests

Component Design Power regulation

Fuse Overvoltage protection Cooling fan Heat sinks

Component Design Motor Control

2 separate motor controllers 1 electronic control unit (ECU)

Component Design Software

User Interface controlled by ECU Directional state machine Closed loop voltage control

of motors CAN, UART, GPIO, Timer,

and Watchdog peripheral

drivers provided by

Stellaris

Component Design Motors

Provide necessary torque to move the wheelchair and user Required to handle:

○ 450 lb maximum weight (user + stroller)○ ± 5° incline/decline○ 3.5 mph max speed

Minimum motor specifications to meet requirements above:○ Power: 0.243 hp○ Torque: 3.22 ft-lb

Component Design Brakes

Electric brakes○ Controlled by software○ Triggered by releasing the touch button

Mechanical brakes○ Controlled by attendant pushing wheelchair○ Consist of hand lever and rim brake (bicycle

brake)

Parking Brakes○ Lock each wheel in place○ Manual lever system

Emergency Brake○ Provide immediate motor stoppage during

emergencies○ Triggered by a simple on-off switch

Component Design Mounting

LCD Touch Button Camera Brakes Motors

Component Design Structure

Adjustable length Storage Material: Aluminum 6063-T6

Final Design

Final Design

40 45 50 55 60 65 70 75 80 850

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Motor Current and Voltage as a Function of Time

Current

Vout

Time (sec)

Mea

sure

men

t U

nit

(V

or

A)

Final Product

Final Product

Significant Issues Funds Schedule Limited manufacturing capabilities

Conclusion Interacting with an actual customer Working with outside companies Scheduling and budgeting Documentation and testing Finalist in RESNA

competition

Acknowledgements Professor VanderLeest Professor Brouwer Carole Pettijohn (Ivanrest Church) Russel Ramsay (Texas Instruments) Tim Theriault (Industrial Consultant) Greg Bush (Gentex) Jim Nammensma (Ebling & Son)

Questions?