一种6R非球型手腕机器人逆运动学算法研究

Inverse Kinematics Solution Algorithm of a 6R Robot with Non-spherical Wrist

6R非球型手腕喷涂机器人得到了越来越广泛的应用,然而这种机器人的结构不满足Pieper准则,导致该机器人的逆运动学求解困难。对此,提出了一种近似解析法和数值迭代法相结合的6R非球型手腕机器人逆运动学组合算法。首先,根据6R非球型手腕机器人的结构特点近似转化为6R球型手腕机器人,并以等效球型手腕机器人的逆运动学解析解作为近似解,采用基于运动学雅可比矩阵的数值迭代法求解6R非球型手腕机器人的逆运动学精确解。其次,针对等效变换引起机器人有效工作空间减小,从而导致算法失败的问题进行了分析,提出了基于目标位姿偏置的方法提高逆运动学算法的鲁棒性。最后,通过数值仿真验证了所提出的6R非球型手腕机器人逆运动学算法的可靠性和时实性。

The 6R spray painting robot with non-spherical wrist has been widely used.However,structure of this kind of robot does not satisfy Pieper-Criterion,leading to the inverse kinematics of this robot a very difficult problem.Then,an inverse kinematic algorithm for the 6R robot with non-spherical wrist is proposed by combining the approximate analytical solution and the numerical iterative method.Firstly,according to structure characteristics,the 6R robot with non-spherical wrist is transformed to a 6R robot with spherical wrist.By taking analytical solutions of the spherical wrist robot as approximate solutions,the Jacobian based iterative method is employed to derive the exact solutions of the 6R robot with non-spherical wrist.Secondly,failure of the proposed method caused by the reduction of the workspace due to structure transformation is analyzed.A target end configuration offsetting method is presented to improve the robustness of the proposed inverse kinematics algorithm.Finally,numerical simulations are carried out to prove the effectiveness and efficiency of the proposed inverse kinematic method for the 6R robot with non-spherical wrist.