下肢助行外骨骼机器人稳定性分析与校正研究

Stability Analysis and Calibration Study of a Lower Limb Mobility-Assisted Exoskeleton Robot

摘要: 为了保证助行下肢外骨骼的稳定运行，构建一种实时检测机器人运转稳定性的控制系统。通过研究零力矩点理论，建立下肢外骨骼的五连杆模型，求取机器人动态零力矩点的理论移动轨迹。以薄膜压力传感器获取机器人运行过程的足底压力信息，更新零力矩点计算公式并获得该点的实际运动轨迹。步态矫正算法调整实际零力矩点的稳定裕度，输出角度调整量，主控模块做角度的反馈控制。调整后轨迹相对于规划轨迹的均方根误差为0.04，稳定裕度增加，机器人稳定性得到提升。

Abstract: To ensure the stable operation of lower limb exoskeleton for mobility assistance, a control system was built to detect the stability of robot’s operation in real time. A five-link model of lower limb ex-oskeleton was developed by investigating zero moment point theory. Determine the theoretical moving trajectory of the dynamic zero moment point of the robot. Plantar pressure information during robot operation was acquired by thin-film pressure sensors. And it was used to update the formula for the zero moment point and to obtain the actual trajectory of the point. The gait correc-tion algorithm adjusts the stability margin at the actual zero moment point. The angle adjustment amount was outputted. And the master control module made feedback control of this angle adjust-ment. The root mean square error of the adjusted trajectory relative to the planned trajectory is 0.04. Stability margin was increased. And stability of robot was improved.