中文摘要：

以6-RSS型并联机构为研究对象，建立解析形式的反向运动学方程，给出考虑驱动副转角范围、球副转角范围、连杆干涉等约束条件时的反解选取准则，推导出每种约束表达与机构参数间关系，特别是复合球副独特的附加约束表达。基于带约束条件的反向运动学方程，利用三维边界搜索法，绘制并联机构多个定姿态工作空间的截面图和三维实体图。最后以工作空间体积为优化目标，获得结构参数和约束条件对工作空间体积的影响关系曲线，为定量分析影响效果提供解决途径，最终利用全局搜索法得到6-RSS机构的一组最优机构参数，在机构整体尺寸基本不变情况下使工作空间增大60％，达到优化机构参数的目的。

英文摘要：

The inverse kinematics of the 6-RSS parallel mechanism is built. Based on the selection rules on the rotational joint fit comer, spherical joint fit comer and parallel bar interference, which are application-based, the relationships between those restrictions and mechanism parameters are deduced in the mathematic functions, especially for the compound spherical joint. The boundary of the constant- orientation workspace is determined in terms of cons- trained inverse kinematics and 3D boundary search method. Several constant-orientation workspaces are illustrated by MATLAB software. The constrained optimization problem of workspace volume is established to present the effects of parameters on the workspace and to optimize those parameters to obtain the maximal workspace volume, which is increased 1.6 times as much as the original volume.