Calibration method and experiment of Stewart platform using a laser tracker

The focus position of Five-hundred-meter Aperture Spherical Telescope may be changed unexpectedly because of the environmental condition such as strong winds. So a Fine Feed Cabin Model based on Stewart platform is used to get rid of the unexpected change by controlling the position and orientation of the platform. To improve the accuracy of the platform, a calibration method by a laser tracker LTD500 is presented and an error compensation experiment is carried out. The position and orientation of the platform can be figured out by LTD500. The measurement configurations can be selected from the boundary of the joint space. After calibration the accuracy can improve to about 0.2 mm and meet the requirement. The experiment result proves that the method using a laser tracker is very useful to calibrate Stewart platform, even if there are no enough measurement configurations.