Help with a wheelchair project

Hello Guys, I am designing a wheelchair conversion kit, so I'm using two gearmotors with a chain drive system. Anyways, I am not an expert with controlling system so I need help with major stuff. I found this motor controller that works with my motors: http://robot-solutions.com/RS3/index.php?route=product/product&product_id=50

So, with this controller I only need to connect the motors and interface the controller with a joystick right? To do so, what other parts should I consider and buy? I mean how can I control the wheelchair with a joystick if I only have two gearmotors and this motor controller.

Thanks in advance

When you attach each motor to a wheel, you can drive forward (both motors fwd), back (both motors back), curve (only one motor on), or turn in place (motors in opposite direction).

The choice of the joystick affects the movement comfort. With a digital joystick you only can move at a single speed, and stop abruptly, while an analog joystick will allow for continuous speed control. A rotatable joystick (3 axes) will also allow to turn the chair in place, in addition to driving curves.

The below discussion might be of interest.

http://forum.arduino.cc/index.php/topic,157967.0.html

DrDiettrich: When you attach each motor to a wheel, you can drive forward (both motors fwd), back (both motors back), curve (only one motor on), or turn in place (motors in opposite direction).

The choice of the joystick affects the movement comfort. With a digital joystick you only can move at a single speed, and stop abruptly, while an analog joystick will allow for continuous speed control. A rotatable joystick (3 axes) will also allow to turn the chair in place, in addition to driving curves.

Thanks for your reply. Do you mean I should consider buying an analog or rotatable joystick? and just interface it with the motor controller?

zoomkat: The below discussion might be of interest.

http://forum.arduino.cc/index.php/topic,157967.0.html

Thank you!

You might consider making an add-on pack for a non powered wheel chair. Below is a previous wheel chair discussion that might be of interest.

http://forum.arduino.cc/index.php?topic=204510.0;nowap

im not sure what you know about electric wheel chairs and arduinos so I will just post the basics

The dc motors on a wheel chair are basic dc motors with built in electrical brake.

The brake is power to release so when the wheel chair is off the brake on the back of the motor is applied.

The normal controls are speed limiting, on/off, battery monitor and joystick steering.

The Ardunio can output a straight dc output or a pwm (pulse width modulated) output. To control the motors you will need to input the variable signal via analog input from the joystick then output a pwm signal to the H bridge drives to control the motors. Another input from a pot (variable resistor) should be read on a analog pin which will be interpreted by the arduino to act as a speed cap for the motors (it will reduce the max pwm output). If you are using proper wheel chair motors you will need a output for the brakes which will require a mosfet or a relay as the arduino can not supply the power required to release the brakes.

Wheel chair used motors are cheap in America at about $50 to $75 including gearbox and wheel for a set. The original controls for a wheel chair are complicated as the source code and program is not open source. (the controllers do fail which is why you can buy cheap motors). Most run on 24vdc with a locked motor current of around 40 amps. A smaller motor with chain drive will work but they lack a brake so the operator will have to be careful when they get out of the chair as it may roll backwards.

Our project is to design a removable conversion kit for wheelchairs with big wheels (24'') so I cannot go with the cheap motors or attach to motors to the wheels and I have to buy gear motors "$279 for each", the braking system doesn't concern us at this moment. So I was thinking of buying this motor controller "http://robot-solutions.com/RS3/index.php?route=product/product&product_id=50" and start programming directly for the joystick.

I'm not an expert in Arduino so i've been studying it all over again for the past two days. The company told me I don't have to buy an arduino board because the controller has a PC port and I can just plug it in and start program it with my own codes. What I'm still trying to find out is do I have to buy other parts to complete the programming or I only need these part " 2 motors, motor controller, 24V lead acid battery, and a joystick" ?

Thank you very much for your reply.

Of course you can build a wheel chair without any controller, by wiring switches directly to the battery and motors. You may try such a solution, to find out what additional steering comfort you want to have, before you start buying additional expensive electronics.

Your proposed MC160 motor driver has RC and RS232 inputs. The RC inputs (most probably) can be used with standard RC controls (switches, joysticks...), where the control modules already provide the required RC pulses - bare bone switches or joysticks are not applicable then. The driver also requires speed feedback, so that you have to add rotary encoders to your inventory list. See the User Manual link in the website. Then you have to configure the driver at least once, using its RS232 connection, that's all.

Is the conversion going to be permanent on the chair, or is to be such that it can easily be installed/removed as needed?