7自由度拟人臂仿人运动的逆运动学解析解

Analytical Inverse Kinematics of Anthropomorphic Movements for 7-DOF Humanoid Manipulators

为了求解末端位姿已知时拟人臂的仿人臂姿,以人臂运动特性为依据,针对7自由度拟人臂提出了一种新的逆运动学求解方法。该方法将人臂的末端运动转化为腕部的达点运动,利用肘部的自运动理论解耦了人臂的冗余度,并结合最小势能指标确定了自运动角。在利用末端位姿确定腕部位置的基础上,依据自运动角求解肘部位置,进而推导出拟人臂仿人运动的逆运动学解析表达式。试验和仿真结果证明了该方法解的仿人性和连续性。最后,从拟人臂的运动灵活性的角度分析了方法的失稳现象,结果表明自运动角发生突变时拟人臂奇异。该方法属于解析方法,有利于对拟人臂进行实时的仿人运动控制。

To obtain anthropomorphic arm postures for a given end-effector position and orientation, a new inverse kinematics method is proposed for seven degrees of freedom(DOF) humanoid manipulators base on the characteristics of human arm postures. The wrist position is determined by the end-effector position and orientation, and then the redundancy resolution of human arm is solved using the elbow twist angle, which is determined by the minimum potential energy measure. Furthermore, the analytical formulation of the inverse kinematics for humanoid manipulators is derived. The results of simulations and experiments prove the similarity with human arm postures and the continuity of the solutions. Finally, the instability of this method is analyzed based on the dexterity of humanoid manipulators, which shows that the humanoid manipulator is singular when the elbow twist angle suddenly changes. Due to the analytical formulation, this method is efficient for the real time control of humanoid manipulators.