机械臂的逆运动学问题可转化为等效的最小化优化问题,并采用数值优化方法求解。提出一种基于类电磁机制(Electromagnetism-like mechanism,EM)和模式搜索(Pattern search,PS)数值求解机械臂逆运动学问题的混合类电磁机制算法(Hybrid electromagnetism-like mechanism,HEM)。该方法利用修改的类电磁机制(Revised electromagnetism-like mechanism,REM)与模式搜索方法各自特性相互融合平衡算法对解空间的全局探索和局部开发能力,基准函数测试结果表明该算法改善了全局搜索性能及寻优解的可靠性。在此基础上以6自由度TX60型号史陶比尔工业机械臂为例,考虑以机械臂末端位姿误差构建适应度函数并采用上混合类电磁机制算法数值求解,仿真结果表明,与其他方法比较,该方法用较少的适应度值计算次数下就能搜索到期望精度的寻优解,并且能搜索到所有可能关节角逆解的潜在能力,验证了该方法的有效性。
The inverse kinematics problem of robot manipulator can be solved through numerical optimization method, which is an equivalent minimization problem essentially. A new hybrid method, i.e. hybrid electromagnetism-like mechanism(HEM), which based on electromagnetism-like mechanism(EM) and pattern search(PS), is presented for computing numerical solutions to the inverse kinematics problem of robot manipulators. This method uses respective merits of revised electromagnetism-like mechanism (REM) and pattern search, and combines to strive for a well balance between the global exploration and the local exploitation. The experimental results of benchmark functions show that this HEM algorithm greatly improves both the global optimization performance and the search solution reliability. Based on these, the 6-DOF Staubli TX60 robot manipulator is used as an example, and the end-effector error(position and orientation) of the manipulator constitutes the fitness function. Then the proposed HEM algorithm is used to solve the inverse kinematics problem. Numerical simulation results show this hybrid can find the desired precision solution with less function evaluations than other several methods, and it has potential capability to find all the possible inverse kinematics solutions, which demonstrates the effectiveness of this hybrid.