Adaptive control of an omni-directional walker considering the forces caused by user

An omni-directional walker (ODW) has been developed to support people with walking impairment to do walking training without the presence of a physical therapist. In order to get a good training effect, the ODW needs to precisely follow the training path which is defined by a physical therapist. However, the forces caused by user make the ODW deviate from the training path. In previous studies, an adaptive controller was developed to deal with the pressure leading to the load change and center of gravity shift of the ODW. However, the forces from used consist of both vertical pressure and horizontal thrust. In this paper, an improved model is proposed considering both the pressure and the thrust. Furthermore, an adaptive controller is designed based on the model to improve the path tracking accuracy. The simulation is carried out and the results demonstrate that the proposed method is effectiveness to control the ODW following the training path accurately.