I am here because I was reading posts with a plan to make an off-road (hopefully beach) vehicle for my wife. My wife lost her hands and feet a decade ago due to sepsis. She can walk a short distance on prosthetic legs on level ground, but uses a compact power wheelchair when we are out and about.
Manual wheelchairs are 2 wheel drive with reverse, and there is no inherent limitation to them making a 90 degree turn in three feet and ejecting the rider. Depending on the person’s disability, they may be stuck until assistance arrives. Because of this some caution is warranted, especially in the testing phase.
Work on a spare chair, not their daily chair.
Have you examined the existing options?
From what you describe, a good option would be one of the kits that adds a single hub wheel to the front of the chair, and lifts the front casters. They are all in one affairs. First a bracket is added to the manual chair, then the:
Can be attached or detached in about 15 seconds.
These usually have about 15 miles of range at 15mph, but they are a good starting point to mod.
If you want to attach motors to the chair’s existing wheels, be aware that the small front casters and the front back center of gravity will be limitations. If you change the castors, their turning radius will be different, and maybe limiting. If you change the center of gravity they may not be able to hop a gap. When you have the chair reverse it may tip them over backwards.
If you want them to have a kick ass chair that uses modern technologies, check out wheelchairdriver both for the home page and the forums.
I am planning on making a joystick controlled chair.
I will use:
opentx for the joystick to differential steering with throttle curves I can draw instead of code
Uumotor hub wheels with built in encoders, I would like better, but that is the best high torque motors with encoders I could find. Qsmotors also make nice hub motors, but they don’t have encoders
Dual vesc esc