Dynamic model based fuzzy-impedance interaction control for rehabilitation robots

During the robot assisted active rehabilitation training, it is very important to adaptively adjust the interaction force between the robot and limbs, online. Aiming at this problem, a fuzzy-impedance control strategy is proposed. First, the difference between the estimated and the measured forces is used to represent the human-robot interaction force. The estimated force is based on rehabilitation robot dynamic model. Then, an adaptive algorithm based on fuzzy logic is presented for adjusting the impedance parameters, including stiffness and damping. Specifically, the interaction force and position errors are used to adjust stiffness, and the interaction force and velocity errors to damping. Finally, the feasibility of the proposed algorithm is verified by the simulation experiment.