Motion Control Of The 2-dimensional And 2-DoF Translational Parallel Manipulator

Compared with the serial robots, the parallel robots have the advantages of high rigidity, high accuracy and good dynamic performance. At present, various types equipments based on parallel mechanisms are becoming an important complement to traditional serial equipments, and playing an increasingly important role in many areas. Motion control of the 2-dimensional and 2-dof (degrees of freedom) translational parallel manipulator patented in our laboratory is studied in this thesis . The main contents in this thesis are listed as follows:First of all, the problem of the optimal time trajectory planning is discussed. From kinematics analysis of the 2-dimensional and 2-dof translational parallel manipulator, the forward and inverse kinematics problems are given, and its velocity and acceleration mapping modes are solved. The piecewise polynomial interpolation method is used to plan the trajectory of two active joints. By comparing the merits of simulation of 4-3-4-orders, 3-5-3-orders and 5-5-5-orders piecewise polynomial trajectory modes, the 4-3-4-orders and 5-5-5-orders piecewise polynomial trajectory modes are selected. Considered the speed and torque constraints in joint space, the optimal time mathematical mode of trajectory planning is established with the objective of minimum time of single pick and place operations. Then genetic algorithm is selected to optimize the trajectory of polynomial interpolation.Then, the motion control system hardware and software are developed and designed. Motion control system of the 2-dimensional and 2-dof translational parallel manipulator is developed by way of the universal, open, real-time "PC + MC" control mode. The motion control unit, servo drive unit and feedback unit of the hardware system are introduced after the overall structure of control system designed. The algorithms of main module are given after the block diagram of control system software designed.Finally, the 4-3-4-orders and 5-5-5-orders piecewise polynomial trajectory modes are experimental studied. The experimental results show that the motion control system hardware and software are reliable and practical; on the other hand the accuracy of optimal time trajectory planning theory is verified. According to the evaluation criteria of manipulator movement, the 4-3-4-orders mode has more advantages in speed; the 5-5-5-orders mode is superior in smoothness. Taking all into account, 5-5-5-orders piecewise polynomial trajectory mode is more applicable.