基于姿态可操作度的机械臂尺寸优化方法

为解决机械臂尺寸优化设计问题,首先定义了表征灵活性的数值指标——姿态概率系数,即指定工作点上可行样本姿态与所取样本姿态之间的比值;之后根据姿态概率系数提出了姿态可操作度概念,它表征了机械臂在工作空间上的整体可操作性.在此基础上,提出了机械臂尺寸优化方法.该方法在机械臂原有结构设计的基础上,以机械臂自身无碰撞为约束条件,以姿态可操作度的倒数为适应度函数,利用遗传算法优化机械臂的尺寸参数,使优化后机械臂的可操作性最优.以六自由度(DOF)机械臂为例的优化结果表明:优化后机械臂姿态可操作度提高了40.33%.最后利用灵活性工作空间图进一步验证了算法的有效性,并讨论了姿态概率系数对优化结果的影响.

Dimensional optimization method for manipulator based on orientation manipulability

To solve the dimensional optimization design problem of manipulator, the numerical index of dexterity was presented by pose probability coefficient, which was defined as the ratio between possibly sampled orientations and sampled orientations of the working point. According to the pose probability coefficient, the concept of orientation manipulability was proposed, which represented the operability of manipulator. On the basis of orientation manipulability, an algorithm of dimensional optimization to manipulator was proposed. Based on the original structure design, this algorithm takes the reciprocal of the orientation manipulability as fitness function. Under the condition of self-collision, dimensional parameters of manipulator were optimized to maximize the operability by using genetic algorithm. Optimization algorithm was applied to a six-degree of freedom (DOF) manipulator. Results show that the orientation manipulability increases by 40.33% after optimization. Finally, validity of the algorithm was further verified by dexterous workspace and the effect of the pose probability coefficient to the optimal results was also discussed.