For some disabled people, the use of a wheelchair can be difficult, due to weak physical capacities or cognitive troubles. So, the human-machine interface must be modular, configurable and easy to implement. It must bring reliability and use non specific material as often as possible. Therefore, the FRACAH project (Fauteuil Roulant A Commande Adaptee au Handicap) has been developed. Its lever is handled by an artificial neural network that records functional limitations of the hand, and then compensates them. Petri nets have been used in order to obtain an easy FPGA implementation of the control. Some examples of obtained results are given.