基于阻抗模型的下肢康复机器人交互控制系统设计

为帮助下肢功能障碍患者进行康复训练，设计了下肢康复机器人。对于该机器人的控制，采用传统系统无法柔顺控制，导致机器人运动轨迹偏离预设轨迹。针对该现象，提出了基于阻抗模型的下肢康复机器人交互控制系统设计。通过分析总体控制方案，设计系统硬件结构框图。采用L型二维力传感器，确定两个方向的人机交互力。使用绝对值编码器安装在各个关节处，其输出值作为髋关节、膝关节、踝关节电机的转动位置，增量编码器安装在电机轴上，测量值用来作为后期控制方法的输入参数。构建阻抗控制模型，能够调节机器人位置和速度，具有消除力误差功能。依据此力矩对参考运动轨迹进行设计，实时获取患者康复训练的跟踪、主动柔顺和接近状态信息。在柔顺训练实验测出人机交互力，通过实验结果知，在检测到人体主动力矩异常时，系统能够重新优化轨迹，具有良好柔顺控制效果。

Design of interactive control system of lower limb rehabilitation robot based on impedance model

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.