Analysis on Servo Control of High-Quality Servo System

Design of double position regulator armed at servo driver whose main objectives are fast position and accurate tracking makes high position accuracy and following speed of system. Among them, semi closed-loop structure is adopted by inner position loop. Position sensor is connected with servo motor coaxially. Position gain can be chosen much higher, so that motor responses rapidly and system dynamics is guaranteed. Closed-loop structure is adopted by external position loop. Position sensor is installed in the executive body of worktable and steady-state position error compensation is only available. Position gain is chosen lower to ensure stability of the system. Based on analysis of the existence of positioning errors of servo motor semi closed-loop structure in the paper, a hybrid structure of position servo system is designed. Detailed analysis of the stability and following performance of double loops is completed. Finally, inner position loop consisted of alternating current servo motor drive and incremental photoelectric encoder locates in the end of motor shaft, and external position loop composed of DSP motion control card, inner loop servo system, ball screw and grating on the worktable forms three-dimensional laser processing driver device. Position control accuracy and following speed of three axes linkage table are ensured, and motion requirements for high speed and high precision of laser engraving machine is met easily.