单自由度可调下肢康复机器人机构优化设计

Optimal Design of an Adjustable One-DOF Robot Mechanism for Lower Limb Rehabilitation

为帮助下肢功能障碍患者完成步态康复训练,设计了一种新型下肢康复机器人机构,提出了机构尺度优化综合方法.首先,以一个两自由度平面五杆机构为基本机构,通过逆运动学分析建立五杆机构两个输入之间的函数关系,并以曲柄匀速转动为优化目标进行机构尺度综合;然后,在此机构的基础上引入一凸轮-连杆函数生成机构,通过逆运动学分析与机构尺度综合求解并优化凸轮廓线,实现了五杆机构两个输入之间的函数关系,并减少了机构自由度;最后,在此基础上引入一缩放机构,实现机构轨迹可调.以运动捕捉实验获取的正常人体步态轨迹为目标轨迹,进行机构优化设计,结果表明:优化所得机构在匀速电机驱动下能够很好地模拟正常人体步态轨迹与髋、膝关节运动规律,从而验证了机构与优化方法的有效性.

In order to help patients with lower limb disabilities to complete gait rehabilitation,a novel mechanism for lower limb rehabilitation is designed,and the method for optimal dimensional synthesis of the mechanism is also presented.As the first step,a two degrees of freedom five-bar mechanism is selected as the original mechanism,of which the function relationship between the two inputs is established by using inverse kinematics,and then the dimensional synthesis of the five-bar mechanism is conducted,taking the uniform rotation of the crank as the optimization goal.In order to implement the established function relationship and reduce the mobility of the mechanism,a cam-linkage mechanism is introduced and the cam profile is optimized by using inverse kinematics and dimensional synthesis.Finally,a pantograph mechanism is used to adjust the generated trajectory.A target gait trajectory obtained by motion capture experiment is used for the dimensional synthesis of the mechanism.The result shows that the generated trajectory and the hip and knee angles match well with the natural ones.Moreover,a constant speed motor is sufficient for the control of the rehabilitation robot system,which verifies the feasibility of the mechanism and the method.