Auto Disturbance Rejection Control Research Of The Beam Suspended Air Gap In Numerical Control Machine Tool Processing Center

In order to eliminate the friction, maglev technology was applied in gantry-moving type numerical control machine tool in this paper. Maglev technology make beam and guide rail no contact, so that the friction and the ill effects of friction are thoroughly eliminated. Meanwhile, the suspension system of gantry-moving type numerical control machine tool is synchronous suspension; but the paper mainly researches the single suspension system, to ensure the stability of the beam suspension and the anti-interference ability of the control system.Firstly, the author has the profound understanding to the maglev technology research status and the application by reading a large number of domestic and foreign relevant papers. On the basis of the previous research results, the mathematic model and nonlinear state-space equation of single electromagnetic suspension system were established. Linear maglev system was obtained through the local linearization method and the conclusion which the linear maglev system open loop structure is not stable was obtained. Series calibration device was designed to make system stable. The simulation results showed that the design of the correction device can make beam suspension stability and restrain disturbance, but the system output exist the contradiction between rapidity and the overshoot.Secondly, to solve the conflict between the system response speed and overshoot, the nonlinear PID controller was designed to control linear maglev system. The nonlinear PID controller was presented to solve classic PID controller defects. For example, differential signal is not easy to get; overshoot is easy big; the compound mode of error, error integral, error differential is single caused the robust performance restricted. The simulation results prove that the nonlinear PID controller can make beams maglev system stable suspension, no overshoot, fast response, the strong robust performance. The contradiction between the overshoot and response speed of the classic PID control is solved.Thirdly, aim at adverse effects resulted from the internal system parameter variations and external disturbances, the auto-disturbances-rejection controller were design respectively to linear maglev system. Auto-disturbance-rejection control technology had a stronger inhibitory disturbance capability with the model not accurate and various external disturbances. The simulation results prove that the single electromagnetic suspension system auto disturbances rejection control system has good control performance and restrain disturbances. In order to more close to the real, the double loop auto disturbance rejection controller was designed to control nonlinear maglev system. The simulation results show that the auto-disturbance-rejection control nonlinear single electromagnetic suspension system also can make the beam suspension stability, and the internal system parameter perturbation and external disturbance is restrained effectively. But auto-disturbances-rejection controller has more parameters and parameters setting process difficult.Finally, for solving the traditional auto disturbances rejection controller's problems which are much more parameters and complex parameters adjustment, the linear auto disturbances rejection controller was designed to control to control nonlinear maglev system. The linear function was adopted in the three component parts of the auto disturbances rejection controller; the number of parameter was reduced; parameters adjustment process was simplified. The simulation results prove the simplified linear auto-disturbances-rejection controller can meet the control performance requirements.