Integrated Indirect/Direct Adaptive Robust Control Fornc Rotary Table Direct Drive Servo System

Based on the project supported by National Natural Science Foundation of LiaoningProvince “The research on high stiffness precision control strategy for direct driveNumerical Control (NC) rotary table”(NO.201133029). For the characteristic of the ringPermanent magnet torque motor used in the direct drive NC rotary table servo systemsuffering from the effect of parameters variations and external load disturbances and therequirements of robustness and positioning accuracy should be considered for the NCrotary table servo system., indirect/direct adaptive robust control which combined withindirect adaptive robust control and direct adaptive robust control, is proposed to enhanceservo performance.The traditional drive mode, which is generally the rotating servo electrical machinewith worm wheel, worm pair and gear pair mechanism, results in slow motion responseand other nonlinear errors due to mechanical transmission chain, thus it very difficult toimplement high precise processing. The rotary table servo system adopting direct drivetechnique has large thrust, high position precision. However, the system is more sensitiveto uncertainties such as load disturbances and inertia variations, which greatly reducesservo performances. For various uncertainty factors, synthesize indirect/direct adaptiverobust control is used to suppress the influence caused by external disturbance andparameters variation and assurance system positioning accuracy and robustness. Itguarantees the accuracy of parameter identification and improves the rapidity, meets therequirements of the positioning accuracy and improves the performance of the servosystem. For the systems with input dead zone, the adaptive robust control with dead zonecompensation based on synthesize indirect/direct adaptive robust control is used. Itestimates the dead zone parameters through the monitoring system operation, makes thedead zone inverse by the dead zone model to realize dead zone compensation. The permanent magnet ring torque motor is selected as the direct drive motor, TypeRM410/100ring torque motor produced by Germany CyTec company is considered as thecontrolled object, its mathematical model is established, and it is necessary to simulate andanalyze above two control strategies using MATLAB software. Simulation results showthat the proposed controllers meet the requirement of robustness and rapidity forhigh-speed high-precision rotary table servo system.