永磁变刚度柔性关节的力学分析与控制器设计

Mechanical Analysis and Controller Design of the Permanent Magnetic Variable Stiffness Flexible Joint

提出一种采用永磁弹簧、绳索驱动、梯形布置的拮抗式变刚度柔性机器人关节,能够根据任务需要,实时调节关节刚度。所述永磁弹簧装置,在绳索提供力矩一定的情况下,增加了关节刚度变化范围,同时减小操作臂的质量与惯量。对提高柔性机器人关节的运动性能具有重要意义。对关节空间与绳索空间的映射关系进行推导并利用雅可比矩阵和模型间静力学关系,得到关节刚度模型,进而实现关节刚度与位置解耦。以轨迹控制为目标,设计了一种双闭环解耦控制器,并进行了试验验证。仿真分析与试验结果共同表明,该柔性关节在较宽刚度调整范围内,都具有较好的位置响应特性和轨迹跟踪能力。上述结构与控制方式同样也适用于多自由度并联柔性机器人关节。

An antagonistic variable stiffness flexible robot joint with magnetic spring,wire-driven and trapezoidal arrangement is proposed,which can adjust the joint stiffness in real time according to the task requirements.The magnetic spring device increases the variable stiffness range of the joint,without increasing the wire tension,while reducing the weight and inertia of the operating arm.It is of great significance to improve the joint performance.The relationship between the joint space and wire space is promoted and Jacobi matrix and static relationship between the models are used to obtain the joint stiffness model,which realize the decoupling of stiffness and position.Based on trajectory control,a double closed-loop decoupling controller is designed,then do experimental verification.The simulation and experimental results show that the joint has good position response and trajectory tracking ability within a wide stiffness range.This configuration and control method is also suitable for multi-degree of freedom parallel joints.