Augmented variable center of rotation in controlling a robotic walker to adapt user characteristics

Abstract

This paper propose a new control algorithm for a robotic walker based on augmented variable center of rotation(COR) to adapt user's controlling characteristics. The new CORs will be taken from environment-based training. This is done by allowing the user to use the robotic walker from a start point to a goal point in a training environment and path following algorithm will be employed. The user's intention represented by applied force/torque will be logged during training. The logged data will be segmented to correspond the straight and curve segments in the training environment. This data will be used to regenerate the path of the robotic walker. The error between the regenerated and the desired path will be taken and in case large path error exists, an optimization program will be used to change the COR until the sum of the square of the path error is minimized. This approach refers to an offline COR determination. A variable COR controller as a function of applied torque will be designed based on the new CORs. This will be augmented and used in the actual control of the robotic walker. The proposed control algorithm was experimentally implemented and results show its validity. © 2005 IEEE.