Research On 6-3 Platform Parallel Kinematics Machine

In comparison with traditional serial kinematic machines, The parallel kinematic machines based on parallel mechanism have positive characteristics such as less motion mass, higher machining accuracy, higher processing speed and lower manufacturing cost. Taking 6-3 platform as a research object, the research on kinematics, structure, interpolation algorithm, control of parallel kinematic machines is done, and a CNC software based on quaternion is developed.Firstly, quaternion theory and their application on rotation of rigid body are given. Based on quaternion, a analysis about inverse kinematics and coordinate transformation of parallel machines is presented, and by that a conclusion is drawn that dual quaternion which is used to express transformation have some advantages such as more concise, faster calculation and less memory.Secondly, the new Jacobian matrix of 6-3 platform is deduced. Two global optimizing indexes are presented. The structural size of 6-3 platform is optimized by optimizing indexes and cond of Jacobian matrix.By researching on a line and a circular arc interpolation, traditional interpolation algorithm for machine tools is illustrated in both mobile and rotational space and implemented by C++. By analyzing disandvantage for linear interpolation of Euler angles, sphere linear interpolation based on quaternion theory is offered. The advantage and disandvantage are compared between these two algorithms. The analysis results are obtained that sphere linear interpolation based on quaternion has some advantages such as continuity and stationarity. Based on cubic spline and Euler parameters, the problem of multi-position interpolation in both two spaces is solved.Extra DOF of 6-3 platform parallel platform are planning by differential evolution algorithm; Merit and demerit for traditional PID controller are analyzed, and then Fuzzy-PID control algorithm is introduced for 6-3 platform parallel platform. Simulation of The control system is performed in MATLAB/SIMULINK. Result of simulation is descriped: Fuzzy-PID control algorithm has more effective performance.By analyzing software and hardware structure of the CNC System for parallel kinematic machine, a CNC software in the nature of 3D runtime display is developed by Visual C++ and OpenGL, and that is based on Open CNC System whose hardware is IPC+PMAC. Development of the software is derived by quaternion and software modularization.