Research On The Position Measurement Of Parallel Mechanism Based On Binocular Vision

Parallel Robot is used widely in industry. However, because of the limitation of the manufacturing level, the position and attitude of the parallel platform are not ideal. Thus researchers need to grasp the position and attitude information of parallel robot in real time.Researchers have applied various methods to realize pose measurement. Beside of the traditional sensor method, there is a new visual technology to observe the robot. It is used to obtain the space position of the object, in which researchers can easily to obtain the observation object`s position. The combination of machine and vision is proved to be timesaving and high efficiency.In this thesis, the kinematical principle and kinematics characteristic of 3-PSS/S parallel mechanism are analyzed, the model of binocular stereo vision measurement system is established; the structure of the system is introduced. In addition, the method of the end position of the parallel mechanism based on the feature point is preliminarily determined. Then the thesis studies the digital image processing, vision camera calibration, which lays the foundation for the follow-up survey, and pro processing of image. The most important work is focused on obtaining sub-pixel information based on Zernike moment method. Actually experiments also show that this Zernike method can obtain higher accuracy. The space position and pose of the parallel platform are studied, and the characteristics of the distribution of the characteristic points and the position and pose of the parallel manipulator are studied. A simple and practical method is given, which is called four points method.Finally, in this thesis, laser tracker is used to measure the moving platform. By compared of two kinds of dynamic static measurement methods, high accuracy of binocular vision measurement method is verified.