基于工作空间分析的9自由度超冗余串联机械臂构型优化

Configuration Optimization of Nine Degree of Freedom Super-redundant Serial Manipulator Based on Workspace Analysis

提出基于工作空间分析解决超冗余串联机械臂构型选择问题的方法。首先,采用正态分布对求取机器人工作空间的蒙特卡洛法进行改进。用归一化可操作度指标分析机械臂运动的灵活性,用数值仿真的方法得到了最大可操作度值与随机关节角组合的数量之间的关系,提出求取灵活工作空间的算法。其次,基于得到的工作空间,提出一种体元化算法求取工作空间的体积,寻找到工作空间的边界部分和非边界部分,通过对边界部分的不断细化,降低了体积求取误差。然后,分析多自由度串联机械臂构型设计方法,针对9自由度超冗余串联机械臂,确定出了36种待选择的构型方案。仿真分析9自由度超冗余串联机械臂的工作空间,在待选构型中选取了一组最优构型。结果表明:改进的蒙特卡洛法生成了精确的工作空间;体积求取算法效率较高,相对误差小于1%;所选构型的工作空间指标优于已研制的构型,其中可达工作空间体积提高了26.49%,灵活工作空间体积提高了36.63%。

A method to solve the problem of configuration selection of super-redundant serial manipulators based on the workspace analysis is proposed. The Monte Carlo method for the robot workspace is improved using normal distribution. The normalized maneuverability index is used to analyze the flexibility of the manipulator’s movement. The relationship between the maximum manipulability value and the number of random joint angle combinations is obtained by numerical simulation, and an algorithm to obtain a flexible workspace is proposed. Based on the obtained workspace, a voxelization algorithm is proposed to obtain the volume of the workspace, and the boundary and non-boundary parts of the workspace are found. Through the refinement of the boundary part, the volumetric error is reduced. A multivariant serials manipulator configuration design method is analyzed. For the nine-degree-of-freedom super-redundant series manipulator, 36 kinds of configuration schemes to be selected are determined. The workspace of the nine-degree-of-freedom super-redundant series manipulator is simulated and analyzed, and a set of optimal configurations is selected in the candidate configuration. The results show that the improved Monte Carlo method generates accurate workspace;the volume extraction algorithm has high efficiency and the relative error is less than 1%;the workspace index of the selected configuration is better than the configuration developed by this research group. Reachable workspace volume increases by 26.49% and flexible workspace volume increases by 36.63%.