以一种平面2自由度驱动冗余并联机器人为研究对象,对该机器人机构尺寸进行量纲一化,给出反映机构几何参数变化范围的空间模型,建立机构的运动学方程,得到位置反解和速度雅可比矩阵.定义并计算机器人的全域性能指标,探讨机器人的雅可比矩阵条件数、承载能力及刚度等全域性能指标与机构杆件尺寸之间的关系,并在空间模型内绘制相应的性能图谱;根据性能图谱,总结三种性能指标在空间模型内的分布规律,分别给出每种性能指标值较好的机构尺寸范围;最后对三种性能指标较好的尺寸范围进行了综合,得到同时考虑三种性能指标优化的最佳尺寸范围.这些图谱使机器人依据运动学性能指标进行优化设计成为可能,图谱分析为实现并联机器人机构设计的计算机辅助设计提供了一种简单、有效途径.
As the subject investigated, the planar 2-DOF parallel manipulator with actuation redundancy is treated as non-dimensional structure. The physical model of the solution space, which can reflect the scope in which the geometric parameters change, is presented. Kinematic equation is established, solution to inverse kinematics and velocity Jacobian matrix are given. The global performance indices of the manipulator are defmed and calculated. The relationship between link lengths and global performance indices, such as condition number of Jacobian matrix, payload and stiffness are discussed; corresponding atlases are plotted in the physical model of the solution space. According to these atlases, the distribution rule of the three performance indices in the physical model of the solution space is concluded; the better dimension scope of each performance index is made out respectively. Finally, when the three performance indices are considered as the optimum indices simultaneously, the optimal dimension scope is obtained by synthesizing the three dimension scopes. These atlases give a possible path to optimize manipulator using kinematic performance indices. This method also provides a simple and effective way for designing parallel manipulator using computer-aided.