1 / 28

APW Air Powered Wheelchair

APW Air Powered Wheelchair. Team: Aaron Breault Bryant Langley Keith Willis. Background. Electric Wheelchairs have limited range Require a recharge that takes 8-14 hours Have difficulties functioning in wet and hot conditions Short battery life of abou t 6 months

dustin
Download Presentation

APW Air Powered Wheelchair

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. APWAir Powered Wheelchair Team: Aaron Breault Bryant Langley Keith Willis

  2. Background • Electric Wheelchairs have limited range • Require a recharge that takes 8-14 hours • Have difficulties functioning in wet and hot conditions • Short battery life of about6 months • Battery replacement cost of $240 or greater

  3. Problem Statement • To design a pneumatic powered wheelchair that has the capability to be “refueled” quickly • Has to have the ability to move a person of at least 300 pounds • Has to incorporate variable speed control • Needs to be able to be reversible • Needs to be able to achieve a maximum speed of 10 mph • Needs to be able to be controlled precisely

  4. Our Solution • 90⁰ Pneumatic piston motor with microprocessor timing control • DC Motor powered steering • Air tank with flow rate control and encoder feedback

  5. System Diagram AirPiston Air Tank Connectingrod Flow rate controller Chair Pneumatic Joystick Air solenoid Crank shaft Controller Encoder Steering Wheels Encoder Driving wheels

  6. Area of Responsibilities Aaron Bryant Keith Steering System Pressure & Flow Rate Regulation System Pneumatic Motor Control System

  7. Steering System

  8. Steering System Diagram

  9. Steering State Diagram Left 1 Home Right 1 Left 2 Right 2 Left 3 Right 3 Left 4 Right 4 Left 5 Right 5

  10. Pressure and Flow Rate Control MCU Stepper Motor Pressure Limiter Pressure Sensor To Directional Control 5 gal. 100 psi Storage Tank Needle Valve

  11. Volume Calculations Storage Tank 135 psi 5 gal. 1 gal = 0.13368 (5 gal) 0.6684

  12. Volume Calculations Cont. Pneumatic Cylinder stroke = 3 in bore = 1.25 in Side without rod Side with rod 1.5 – 0.44 = 1.06 in

  13. Flow Rate Calculations 2.651 (2) + 1.323(2) = 7.948 total volume per rev. Max rpm = 112 rpm @ 10 mph 8 = 896 896 Min rpm = 33.6 rpm @ 1 mph = 268.8 268.8 = 0.1556 cfm

  14. Stepper Motor and Needle Valve Coupler • Stepper motor coupled with turn screw of needle valve. • Motor controls flow rate. • Number of turns related to flow rate Stepper Motor Needle Valve

  15. Supply Exhaust To flow rate subsystem Microcontrollerdas Motor System Joystick Crank position Sensor Crankshaft

  16. Motor Design

  17. Motor Crankshaft design 155Lbs 155Lbs

  18. Crankshaft Stress Analysis

  19. Point of application of force Motor Torque Required Applied force F Connecting rod 18Lbs Measured force=18Lbs Wheel Dia.= 10in Torque to move a cart=7.5ft-lbs 10” Point of rotation Torque Out of Motor Design Max Torque parameters Piston force=F=155lbs Crank radius=r=1.375 Piston Torque = τ = rFsinѲ Crankshaft radius to point of rotation r to point of force Ѳ Torque=F*r(sinѲ)

  20. Motor Torque

  21. Motor Speed, Gear Ratio & Chain Designation 122.307Lbs 97.82Lbs Gear Ratio Circumference=(Pi*10in)=31.4in/rev Maximum speed required=10mph Rpms at axle=336.3Rev/Min Rpms required at motor=100 Max Ratio=1:3 Rpms at motor=336.3/3=112.1Rpms 3:1 Force on Chain Max motor torque = 25ft-Lbs Force on chain from sprocket = 122.307Lbs Max Opposing Axle Torque= 7.5ft-Lbs Force on sprocket= 97.82Lbs Maximum Force applied to chain=220.127Lbs ANSI ROLLER CHAIN CHOSEN= #41 chain, maximum load capacity= 314Lbs

  22. Motor Electrical design 57344 Joystick Dead zone 65535 Potentiometer 5V 0 Quadrant 4 Quadrant 1 8192 Wiper of Potentiometer PTB 0 Microcontroller Piston 1 Extend 40960 PTE 0 Piston 1 Retract 12V 12V Quadrant 3 Quadrant 2 12V 12V Extend=X Retract=R ON=1 OFF=0 PTB 1 PTE 1 Piston 2 Extend PTE 4 Piston 2 Retract 24575 PTE 5

  23. Budget

  24. Schedule

  25. Schedule

  26. Questions

  27. Calculations for Max Travel 2∏r= circumference r=.856” of sprocket Circumference = 5.43” 360ᵒ/5.43”=66.3ᵒ/1” 66.3X1.5”=99.45ᵒ MAX travel in either direction

More Related