Damping smart pi control method for large time-delay systems

Abstract

The fundamental reason why the process with large time-delay is difficult to control is that the information feedback is not timely, which makes the controller based on the feedback information seem powerless to this type of system. Aiming at the control problem of the large time-delay system, a damping wisdom proportional-integral (Damping Wisdom Proportional-Integral, DWPI) control method independent of the controlled object model was invented. In this method, the damping factor is introduced into the proportional gain, and the gain of the DWPI controller can be adjusted according to the estimated value of the time lag and the estimated value of the system time constant. Theoretical analysis shows that the closed-loop control system composed of DWPI controller is not only globally asymptotically stable, but also has good anti-disturbance robustness and parameter perturbation robustness. Numerical simulation experiments have verified the correctness of theoretical analysis, so it is an effective control method and has wide application value in the field of time-delay system control.

Description

technical field [0001] The invention relates to a control method of a large time-delay system, in particular to a damping intelligent PI control method. Background technique [0002] Time lag widely exists in industrial processes such as petroleum, chemical industry, power grid, nuclear reactor, and wastewater treatment. These industrial processes can often be simplified as one or more first-order plus-purity lag systems. Because of the existence of the time lag phenomenon, the control quantity of the system cannot respond to the dynamic changes of the system in a timely manner, which leads to the undesirable phenomena of large overshoot and long response time in the entire system, and even oscillation or instability. It brings great challenges to the design of time-delay system controllers. Therefore, solving the time-delay system control problem is of great significance to the precise tracking of the target trajectory and the stability of the system. For the control pro...

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Problems solved by technology

However, the error and the integral of the error are two completely different physical quantities (physical quantities of two different dimensions), and the inventor of this patent believes that there is obvious irrationality in the traditional PI control law model: (1) the error and the integral The independent weighted summation of two physical quantities with completely different attributes violates the basic arithmetic operation rules; (2) the mathematical model of the traditional PI control law cannot be accurately understood in the physical sense; (3) the mathematical model of the traditional PI control law is not It is different from forcibly separating and treating the two links with different attributes of error proportion and integral separately, which leads to the fact that the two links of error proportion and integral are independent of each other in the control process, and thus lack the science of coordinated control (4) Because of the irrationality of the traditional PI control law model, for more than 80 years, the problem of PI parameter tuning has been the main problem that has plagued scholars and engineers in the fields of control science and control engineering at home and abroad.

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