Heather got a new wheelchair a year or two ago with a tilt feature. It helps her pain immensely to be tilted back, and the control to tilt back is relatively easy for her to manipulate, so she stays that way most of the time. Unfortunately, she can't make it tilt forward on her own. There is a safety feature preventing the wheelchair from moving when she is tilted back, which results in her yelling for us to come tilt her forward whenever she wants to move. She doesn't really understand why this happens, except that she gets "stuck." This is especially problematic when out shopping, as she tilts herself back every time we stop to look at something.
What we need is to sense when she tries to move, and automatically tilt her forward first. Possibly also create a switch to lock out the tilt back feature, for when we need her to be able to move quickly when we're doing a lot of stop and go. This will require interfacing with the limit sensor and controls in a non-destructive way, as this is very expensive machinery that takes a long time to replace if it breaks.
Information is a little hard to come by, although there are a few hackers out there using wheelchair bases as robots. Here's one example. First step will be to reverse engineer the hardware interface, and design a way to quickly and safely connect and disconnect my experiments. I only have hardware access while she is sleeping.