Research And Application Of ADRC In Temperature System

With decades of years development, PID algorithm has become one of the most widely and universal control strategies, for its simpleness, stability and reliability. However, as a result of the nonlinearity and time varying in industry producing process, classical PID controller cannot bring well effect. Though having good control capability, the parameter tuning theory of ADRC (Active Disturbance Rejection Controller) is not perfect, which is not well applied.Under this background, this paper mainly aims to study nonlinear PID controller, active disturbance rejection controller, Smith predictor controller and feedforward controller. In order to improve the stability, this paper puts forward ADRC-Smith predictor controller and feedforward ADRC controller, which is applied to large-lag temperature control system, and then brings the solutions of blow molding control system. After a mass of theory study, emulating and experimentation, the solution reaches well effect. The major works of this paper are summarized as follows:1. The status and characteristic of active disturbance control and temperature control have been studied.2. The development of ADRC is studied and the theory and advantage are deeply studied. ADRC has better characteristic than PID when the object is nonlinear, but parameter tuning theory is not perfect, so is not widely used.3. Via MATLAB emulating, the parameter of ADRC is found. Via unifying the parameter, the aim of simplifying the tuning is reached. Experiment is taken on non-lag platform, and the feasibility of parameter tuning discipline is confirmed.4. ADRC is applied to large-lag temperature control system. If the time lag system is equivalent to one order system, the order of ADRC must be increased, and the number of parameters is increased, which increase the difficulty of tuning,while lacking principle of parameter tuning. The paper combines the ADRC with Smith predictor controller and feedforward controller to make ADRC-Smith predictor controller and feedforward ADRC controller to solve large-lag control problem. The advantage of the two new controllers is that the order will not increase, which is a new approach to resolve uncertain time lag control problem, and is innovation in ADRC controller application.5. Experiments on large-lag platform based on PCC (Programmable Computer Controller) are taken and the control effect is compared with the special temperature controller PIDXH. The result indicates that feedforward ADRC controller is better than PIDXH in stability, robustness.6. The solution of blow molding machine control system is researched, and feedforward ADRC controller is tested in blow molding machine. The control effect is good and the feasibility of the algorithm is validated.