Research On High-precision2D Turntable Based On Optical Gratings

Precision turntable is a complex electromechanical integration equipment, widely used in aviation, aerospace, precision manufacturing, precision measurement, robotics, medical, reverse engineering and other fields. Because of the lack of precision machining, made common turntable angular accuracy is difficult to reach second grade. In order to improve the accuracy of the turntable, the subject of the displacement sensor as a point in a raster feedback element, the incremental PID algorithm for closed-loop control to improve the accuracy of the turntable. The major works are shown as following:First, the use of Renishaw’s raster and raster data acquisition card, realized the turntable angle measurements and the raster data and servo encoder output compare, through a large number of experiments have been turntable angle error;Designed a PC program that can simultaneously read raster data and servo motor encoder output, and servo controller output instruction. On this basis, the use of the grating and the PID feedback algorithm to achieve a closed-loop control of the horizontal axis turntable. The experimental results show that by the grating sensor feedback compensation method, the horizontal axis is the angle error in the whole measuring range from4arc minutes to5arc seconds.