六自由度模块化机器人手臂奇异构型分析

摘要

Aimed at 6-DOF modular manipulator,singular configurations was analyzed within its workspace.Firstly,modular manipulator system was constructed,and the forward kinematics model was conducted by using the DH method.Secondly,combining the kinematics equation,the Jacobian matrix was constructed by using method based on link speed of manipulator,and all the singular states of the manipulator was solved through the method of singular decomposition,all the singular points within its workspace were acquired and the corresponding configurations were shown.Lastly,simulation analysis of manipulator with singular configurations was completed based on the manipulability flexible index and the minimum singular value flexible index by means of the robotics toolbox,changing of the manipulability,the smallest singular value and the Jacobian matrix rank of manipulator were shown during each joint rotting within its range,and the manipulability ellipsoid of end reference point of manipulator was explored when manipulator was in singular configuration.The simulation results showed that the manipulator had three singular states within its workspace,and the manipulability and the minimum singular value were tended to zero,the Jacobian matrix was rank-reduced and the position manipulability ellipsoid of end reference point of manipulator was reduced to a plane when manipulator was in each singular states above.Simulation results verified the correctness of the singularity analysis,and laid a foundation for subsequent trajectory planning research and singularity avoidance research of modular manipulator.%对六自由度模块化机器人手臂工作空间内的奇异构型进行了分析.首先搭建模块化机器人手臂系统,并采用DH法对其进行结构建模,得到正运动学方程;其次,结合机器人手臂的正运动学方程,采用基于机器人连杆速度的方法构造其雅可比矩阵,再基于雅可比矩阵求解机械臂出现奇异状态的所有构型情况,得到所有奇异点并分别给出相应的手臂构型;最后,基于可操作度灵活性指标和最小奇异值灵活性指标应用Robotics工具箱对机械臂的奇异情况进行仿真分析,并考察机械臂处于奇异位型时末端参考点的可操作度椭球情况.仿真结果表明该机械臂共有3种奇异情况,验证了上述机械臂奇异位型分析的正确性,为后续模块化机械臂的轨迹规划研究和奇异点规避研究奠定了基础.