Stability analyses of wheelchair robot based on “Human-in-the-Loop” control theory

The eight leg-wheels hybrid stair climbing wheelchair robot, was developed for aged and disabled person helping them moving freely in structured three-dimensional environment. The efforts of motion automation have been partly implemented, such as climbing up/down the stairs, traversing slope and obstacles, nevertheless without carrying the person. The person is the passenger, also the control object, as the same time the pilot of the wheelchair. Since the person in wheelchair changes his/her posture uncertainly, it is difficult to obtain a better solution of control only by thinking the model of wheelchair. This paper uses the wheelchair as the platform, and describes the entire closed-loop modeling and stability analysis together with its passenger, based on the control theory of ldquoHuman-in-the-Looprdquo.