Abstract:In order to help patients with lower limb dysfunction to perform rehabilitation training, a lower limb rehabilitation robot is designed. For the control of this robot, traditional systems cannot be used for compliance control, which results in the robot's motion trajectory deviating from the preset trajectory. In response to this phenomenon, the design of an interactive control system for a lower limb rehabilitation robot based on the impedance model is proposed. By analyzing the overall control scheme, the hardware block diagram of the system is designed. The L-shaped two-dimensional force sensor is used to determine the human-computer interaction force in two directions. The absolute value encoder is installed at each joint, and the output value is used as the rotation position of the hip, knee, and ankle motors. The incremental encoder is installed on the motor shaft. The measured value is used as the input parameter of the later control method. The impedance control model is constructed, which can adjust the robot position and speed, and has the function of eliminating force errors. The reference motion trajectory is designed based on this moment, and the tracking, active compliance, and approaching status information of the patient's rehabilitation training is obtained in real time. The human-computer interaction force was measured during the compliance training experiment. It is known from the experimental results that the system can re-optimize the trajectory when an abnormal active moment of the human body is detected, and has good compliance control effects.
