Abstract:

In order to enhance singularity robust stability,accuracy of motion control and reduce control energy,motion control of parallel mechanisms in the presence of drive singularities was researched.A three-revolute-prismatic-revolute(3-RPR) planar parallel mechanism was taken as an example,by means of screw theory and multi-body system dynamics theory,its kinematics were analyzed,its dynamics model was set up,and then motion controller was designed respectively using an improved hierarchical sliding mode control method and a pseudo-inverse based sliding mode control method.Finally,stabilizing control simulation for a two different typical singular points within its workspace was carried out with the arbitrarily given initial points.The simulation results show that anyone of the two control methods can achieve very high control precision and very quick respond,but the quantity of the drive inputs and control energy of the former is more little,the research results provide a new way for the solution to drive singularity problems of motion control of parallel mechanisms in their practical applications.

Key words: parallel mechanism, drive singularity, screw theory, dynamics control, sliding mode control

摘要：

以提高奇异鲁棒稳定性、控制精确性和降低控制能耗为目标，研究了并联机构的驱动奇异运动控制。以3-RPR型并联机构为例,运用螺旋理论和多刚体动力学理论进行了运动学分析和动力学建模;分别采用基于分层递阶结构的滑模控制方法和基于伪逆的滑模控制方法设计了运动控制器,对工作空间内不同的典型奇异位置进行了镇定控制仿真。结果表明,这两种控制方法均可达到较高的控制精度和较快的响应速度,且前者控制输入量更小、能耗更低。

关键词: 并联机构, 驱动奇异, 螺旋理论, 动力学控制, 滑模控制