基于改进LM法的机器人逆运动学求解

Robot Inverse Kinematics Solving Based on Improved LM Method

以不满足Pieper准则的串联机械臂为主要研究对象,针对逆运动学求解存在的精度低、收敛速度慢以及通用性差等问题,提出了一种适用于各类串联机械臂求逆解的改进Levenberg-Marquardt算法。根据改进D-H参数法建立了机器人运动模型,以最小化位姿误差为目标构建了逆解问题的目标函数;通过收敛因子非线性更新、信赖域法调整收敛步长以及延用迭代初值等3种策略得到了一种改进LM法,并将其用于逆运动学求解;最后在MATLAB环境下进行仿真试验。结果表明,改进的LM法具有收敛速度快、稳定性能好、精度高等特点,证明了该算法求逆的可行性与有效性。

Taking the tandem robotic arm that does not satisfy Pieper′s criterion as the main object of study,an improved LM algorithm is proposed for the inverse solution of various types of tandem robotic arms with low accuracy,slow convergence speed and poor generality of the inverse kinematics solution.The robot motion model is established according to the improved D-H parameter method,and the objective function of the inverse solution problem is constructed with the goal of minimizing the positional error.An improved LM method is obtained by three strategies,such as nonlinear update of convergence factor,adjustment of convergence step by trust domain method and extension of iterative initial value,and it is used for the inverse kinematics solution.Finally,simulation tests are conducted in MATLAB environment,and the results show that the improved LM method has the characteristics of fast convergence,good stability performance and high accuracy,which proves the feasibility and effectiveness of the algorithm for the inverse.