Development of an Extended Operational Kalman of Power Assist Wheelchair

An operational state observer for a wheelchair system we have proposed is extended to three dimensions. This new observer incorporates a 3-axis accelerometer allowing the user to estimate more precise information on conditions of hills for the lateral direction. First, a model dynamics illustrating the relationship between the gravity in the lateral direction and the motion of a wheelchair on a slope is derived enabling us to design a state observer that estimates the direction of the gravity. Experimental results verify our derivation of equations. Then, the derived dynamics is simplified and used in the design of the extended observer. Since the dynamics itself and the output of that have nonlinear characteristics, the extended Kalman filter design algorithm is employed. By simulation, the stability and effectiveness of the application is verified.