High Performance Motion Control And Its Application To CNC Systems

High-speed high accuracy motion control is recognized as one of the most important areas in manufacturing, which is the kernel technique in high-speed machining center playing an important role in increasing the productivity and quality of manufacturing. However high performance CNC (Computer Numerical Control) system faces many challenges, which require further research effort. One important problem is the design of advanced motion servo controllers in the presence of disturbance, nonlinearities and unmodeled dynamics, the other is the monitoring of high-speed machining process and the machining state of CNC systems. This dissertation focuses on the high performance motion control algorithms and their implementation on the CNC system. According to the idea of synthesizing the error avoidance and error compensation to research, the dissertation is consist of two parts which are servo controller design theory and online error compensation theory. This dissertation has provided some effective methods for solving the challenges mentioned above and the contributions are summarized as follows:1. The design methods for high performance motion controller and its exiting problems are analyzed and discussed systematically. The research idea of synthesizing the error avoidance and error compensation to research is proposed.2. Control strategy model research of CNC system based on the open system architecture. The mathematical model of the feed system of CNC system is analyzed. To improve manufacture performance, the parts and the CNC system are treated as the whole. Based on the open system architecture, the model of control strategy proposed is composed of three parts. They are servo systems, DSP, multisensor information fusion system. The results can also be used to other motion control.3. High performance servo system design based on a disturbance observer. The principle of designing disturbance observer is described and its stability is analyzed. For the feedforward controller design, zero error characteristic of the step response of system with zero phase error tracking controller (ZPETC) is proved and its application is studied. For the feedback controller design, under the condition of that the noise and disturbance had been eliminated through disturbance observer, an anti-windup state feedback controller is proposed to solve the problem in which most of the existing anti-windup schemes can not guarantee the asymptotic closed-loop stability even for open-loop stable systems subjected to actuator saturation.4. High performance servo system design based on nonlinear adaptive robust control. On improving the weakness of strong control while enhancing the stability robustness and performance robustness, the adaptive robust controller with continuous monitoring function design method for single input single output nonlinear system was proposed. Based on the theory and nonlinear model of the CNC system, a simple adaptive robust controller and a general adaptive robust controller for CNC system are proposed to compensate the friction nonlinearity, parameter variation and unmodeled dynamics. The simulation results show that the controller is of better performance compared with the control strategy based on disturbance observer.5. Grey predictive control for time delay system. The principle of grey predictive control is introduced. The main problem is the improvement of the precision of grey model. A new weighted modeling algorithm is presented and the weight value learning algorithm is solved, another integrated modeling method is also presented. Two models can improve the precision compared to the traditional algorithm. By using the method of dynamic analysis of origin neighboring region, the condition and the number of critical steps while no oscillating occurred in time delay systems are obtained. The two important conclusions can offer significant theoretical basis for the parameter design in gray predicative controller. A fuzzy-Gray predictive control algorithm for...