Open Cnc System, Servo Control Technology

Based on the features of the NC servo control system, according to the advantages and disadvantages of PID controller, three kinds of control technology have been proposed. They are Enhanced PID Controller, Repetitive Controller and ADRC (Auto Disturbance Rejection Controller). Based on the theory analysis of the three controllers, the simulation tests in the computer have been carried out. The simulation results show that the ADRC is strong in no-overshoot and no-vibration, but it is weak in celerity. At the same time it is hardly to be realized on the system. So, the Enhanced PID Controller and Repetitive Controller have been chosen as the servo control technology applied in the open NC servo system and the experimental tests have been made on the real system. The test results show that the Repetitive Controller is better than the Enhanced PID Controller.The following paragraphs are main context of the paper.1. The general situation of NC servo control and open NC experimental system.2. The introduction of system identification and the identification method of NC servo system. Using M sequences as the input signal, using the data gather function of PMAC to get the input signal and the output signal. Using MATLAB to process the data so as to get the mathematic model of the controlled system.3. The basic principle of PID controller and the enhanced PID controller. The introduction of the parts of the controller, including the proportion, the differentiator and the integrator, etc. The introduction of the functions of these parts and the simulation analysis of the controller in computer.4. The basic principle of Repetitive Controller and the parts of the controller. Including the internal model, low pass filter, feed forward and compensators. The analysis of the Repetitive Controller stability and the simulation analysis of the controller in computer.5. The basic principle of ADRC and the parts of the controller, including the TD (Tracking Differentiator),ESO(Extended State Observer) and NLSEF (Nonlinear State Error Feedback). The theory analysis of the three parts and the simulation analysis of the controller in computer.6. Introduction of the user-servo technology based on PMAC. The servo control program of PID Controller and Repetitive Controller according to the computer simulation results. The realization and the test of the two controllers in the open NC servo system. The test results show that the Repetitive Controller can reduce 71.9% following error caused by the enhanced PID Controller.