Adaptive controller for motion control of an omni-directional walker

Walking is a vital exercise for health promotion and a fundamental ability necessary for everyday life. In the authors' previous studies, an omni-directional walker was developed for walking rehabilitation. Walking training programs are stored in the walker and the walker must precisely follow the paths defined in the walking training programs to guarantee the effectiveness of rehabilitation. In the previous study, an adaptive control method has been proposed for path tracking of the walker considering a center of gravity shift and load change. In this paper simulations and running experiments are carried out to verify the proposed adaptive control method. First, the kinematics and the kinetics of the omni-directional walker motion are described. Second, the adaptive control strategy is presented. Finally, path tracking simulations and experiments are carried out using the proposed method. Comparing with the proportional-integral-derivative control (PID control), the simulation and experiment results demonstrate the feasibility and effectiveness of the adaptive control method.