一种位姿解耦的主操作手结构设计与优化方法

Mechanism design and optimization of a position-posture decoupling master manipulator

摘要:

为提高医生对微创手术机器人主操作手进行操作时的一致性和灵活性,设计一种8关节串联型力反馈主操作手。从位姿解耦角度出发,通过一种双平行四边形结构实现位姿解耦,提高了主操作手在不同位姿下操作的一致性。利用改进后的D-H参数法和逆变换法,分别建立主操作手的正运动学和逆运动学模型,并从运动学角度验证了该位姿解耦策略的正确性。基于蒙特卡洛法,使用MATLAB编程,分析主操作手的最小工作空间。求解主操作手的雅可比矩阵,基于全域性能指标和全域性能波动指标定义了主操作手的综合运动性能指标,并以最小工作空间作为约束,用遗传算法对主操作手的运动性能和结构尺寸进行了分析与优化。结果表明:相比于优化前的初始设计,优化后主操作手的综合运动性能指标提高了15.32%,尤其是具备良好运动性能的工作空间体积增加到原来的3倍,已基本包含手术要求工作区域。主操作手在保证操作一致性和足够工作空间的基础上,具备了良好且稳定的运动性能。

Abstract:

To improve the consistency and flexibility of master manipulator in minimally invasive surgery, an 8-joint series force feedback master manipulator was designed. From the perspective of position-posture decoupling, this design realized position-posture decoupling through a double parallelogram structure, which improved the consistency of operation in different positions and postures. Using the modified D-H parameter method and inverse transformation method, the forward and inverse kinematics of the master manipulator were solved respectively, and the position-posture decoupling strategy was verified from the perspective of kinematics. Based on Monte Carlo method, the minimum working space of the master manipulator was analyzed by MATLAB programming. Then the Jacobi matrix of the master manipulator was solved. Based on the global conditioning index and global conditioning mean square error index, the comprehensive motion performance index of the master manipulator was defined. Taking the minimum working space as a constraint, the motion performance and structure size of the master manipulator were analyzed and optimized through genetic algorithm. The optimization results show that, compared with the initial design, the comprehensive performance index of the master manipulator is improved by 15.32%, and especially the workspace volume with good motion performance is increased to 3 times of the original, which basically includes the operation required work area. On the basis of ensuring the consistency of operation and enough working space, the master manipulator has good and stable motion performance.