Adaptive controller for omni-directional walker: Improvement of dynamic model

An omni-directional walker (ODW) is being developed for both walking rehabilitation and walking support for people with walking disabilities. The ODW cannot accurately follow a training path planned by a physical therapist for walking rehabilitation due to the center-of-gravity shifts and load changes caused by users. To address this issue, a new center-dynamic model of the ODW is derived considering center-of-gravity shifts and load changes. An adaptive control method is shown. Comparison with a dual-loop proportional-integral (PI) controller in simulations shows that the proposed method improves the path tracking accuracy.