On The Measuring And Calibration For The Fine Tuning Stewart Platform Of The Large Radio Telescope

In the system of supporting and tracking of the feed source for Five-hundred Meter Aperture Spherical Telescope—FAST, the real-time cabin tracking and dynamic measuring is a key technique. The positioning accuracy of the feed source is implemented by both a servo system with six cables supporting and a control system of Stewart platform, that is the first system as a coarse subsystem and the second system as a fine tuning subsystem. So the accuracy of the whole system is directly affected by the fine tuning subsystem of Stewart platform, and it is of great importance to improve the accuracy of the fine tuning subsystem.The studies of the structural error and measuring for the Stewart platform are discussed. The main research works can be described as the follows.The conceptions of kinematics of Stewart platform, including pose describing, inverse kinematics, forward kinematics and so on, are delt with. The impact of structural error to the pose of platform is analyzed. The calibration model between poses and kinematical parameters of a Stewart platform is derived from the inverse kinematics solution.The principle of the measuring pose of the Stewart platform is analyzed, and a dynamic measuring system of Stewart platform is established, based on laser tracker. One measuring software is completed, which implements data disposing and collecting, and sends data to a control computer.Based on the calibration model, calibration experiments for the fine tuning Stewart platform are conducted and the structural parameters are amended. The tracking experiments are completed using the measuring software.