Design and Control of a Sitting/Lying Style Lower Limb Rehabilitation Robot with Magnetorheological Actuators

In order to avoid being bedridden, rehabilitation training is essential for stroke patients who suffer from motor dysfunction. A sitting/lying style lower limb rehabilitation robot of 3-DOF has been developed for motion recovery. To overcome the shortcomings of traditional motor control scheme and improve the accuracy as well as flexibility for the robot system, magnetorheological actuators are designed and set in the robot driving system. Relevant calibration experiments are taken to clarify its specific characteristics. Based on the analysis of robot dynamics model, a position-based impedance control method is adopted to accomplish the rehabilitation training strategies, in which the damping parameter is inferred from the interaction force and the velocity according to a fuzzy-based regulator. Finally, simulation results verify the validity of the control method, safety and comfort during training are guaranteed at the same time.