关键词: 并联机构, 驱动奇异, 螺旋理论, 动力学控制, 滑模控制

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