Study Of Kinematics And Motion Control System To A Grinding Machine Tool Based On A Tripod Parallel Universal Wrist

China is now far behind the foreign advanced standards in the field of developing new tools and tool grinding. To improve the overall technology level of our machinery processing and sharpen the competitiveness edge with enterprises abroad, it is urgent to develop new kinds of grinding machine tools which have independent intellectual property rights and have the ability of grinding a variety of high-performance drill. Because of its advantages, such as high stiffness, high capacity and good dynamic performance, fast speed and simple structure, parallel mechanism has received wide attention from international academics and engineering circles in recent years. A new type of grinding machine based on tripod parallel mechanism developed by the Advanced Manufacturing and Automation Institute, Northeastern University makes full use of the advantages of parallel mechanism and sets a new direction for the development of the grinding machine tool industry in China. The paper will focus on the preliminary design and analysis of the motion control system of this new grinding machine tool, and making tests to verify my point. The major contents are as follows:The structure of the machine tool is introduced and the kinematics of the machine tool is analyzed, including the inverse kinematic solution, velocity and acceleration mathematical model for positive solutions. By using of ADAMS/View virtual prototyping technology, the model of the machine tool is simplified. By inputting the kinematic parameters under normal conditions of motion platform and changing its different kinematic parameters, the different simulated forms of machine tool are obtained. The above efforts provide the theoretical basis for the control systems.The control system of the machine tool’s hardware is constructed. Control platform for multi-axis CNC system is set up by adapting the model of open CNC systems which based on PC and motion control card and researching and using PCI-1243U motion controller developed by Taiwan Advantest. Some of the key algorithms of post processor for CNC system is studied, including the establishment of machining coordinate system; track crude interpolation; the analysis of the motion of the machine tool with method of single open-chain, the solution of mathematical model of hook hinges and ball joints, testing the machine tool by interference; the analysis of the end position of the drill, the solution of the value of each drive shaft’s movement when the machine is working with multi-axis.The design of the machine tool’s control software is based on Visual Basic6.0, which makes the machine’s control system have the basic functions needed by the working of the machine tool, including point to point movement, continuous movement, speed change, returning to zero, emergency stop, error report and display of location and speed, etc.Through the grinding test of spiral drill, the feasibility and correctness of the machine tool’s digital control system is verified. Besides the extend ability of machine tools is testified through the oblique hole drilling test.