Research On Coordinate Measuring System Based On Parallel Mechanism

Coordinate Measuring Machine(CMM) is an intelligent precision instrument, which encompasses technology in Mechanical Engineering, Optical Engineering, Electronic Engineering and Computer Science. CMM has become important instruments in industrial measurement, quality control and manufacturing. In this paper, coordinate measurement is divided into two categories. One is about planar(2D) measuring systems, the other is about spatial (3D) measuring systems. We applied planar measuring system to automatically measure wheelset geometric parameters, while the spatial is just a proposal and have not been developed.The parallel mechanism kinematics is analyzed and mechanism geometric parameters are designed. The mechanical components are designed and implemented for the planar measuring system. Through main measuring errors analysis, parameters identification models are respectively developed for both measuring systems and can make instruments high precision without accurate mechanical processing.Additionally, the whole electric components are implemented in the planar measuring system by employing grating sensors and optical encoder with high resolution and low error. The measuring system also has a position and control precision with stepping motors.Finally, the planar measuring system is tested. It completed zero pointautomatic calibration, and automatically measured wheelset geometric parameters. With this, our system overcomes drawbacks caused by traditional manual operation, such as low precision, low efficiency, large resource and power. This test indicates the proposal planar coordinate measuring system can be successfully applied to measure and inspect wheelset profile in vehicle factories.