During a market research, I found the patent EP1512055B1 from 2002. It protects a control-based balancing strategy for wheelchairs in a quite general way. However I know also about the published paper "Front wheel raising and inverse pendulum control of power assist wheel chair robot" from Yoshihiko Takahashi from the year 1999. It presents also a control-based strategy to balance on the rear wheels of a wheelchair. (In fact it uses the exact same method but 3 years earlier).
Therefore, I wanted to ask if the aforementioned patent is righteous?
In reference to the patent: EP1512055B1