Self-adaptive sliding-mode control method for liquid level control system based on Delta operator

Abstract

The present invention discloses a self-adaptive sliding-mode control method for a liquid level control system based on a Delta operator. In process control systems such as liquid control, uncertainty and time delay existing in the control systems may influence stability of the system, thus a sliding-mode control method based on a delta operator in combination with self-adaptive control is provided. A non-linear sliding mode surface is designed, a sufficient condition for asymptotic stability of a time-delay uncertain system is given in the form of linear matrix inequality, input disturbance is taken in consideration, and an upper bound is estimated through a self-adaptive boundary estimation method, so that a complete self-adaptive sliding-mode controller is formed. According to the self-adaptive sliding-mode control method of the present invention, a special non-linear sliding mode surface is designed, thus motion quality of the system is improved; by combining the advantages of self-adaptive control with the advantages of sliding-mode control, the designed control law can have a good control effect when the system has time delay and uncertainty. The self-adaptive sliding-mode control method is used for a liquid level control system with time-varying delay and system modeling uncertainty.

Description

technical field [0001] The invention relates to an adaptive sliding mode control method of a liquid level control system based on a Delta operator, belonging to the field of process control. Background technique [0002] In modern industry, automatic control technology is widely used. Many control systems use process parameters such as temperature, pressure, flow, liquid level and composition as controlled variables to achieve stable control of the system. On the other hand, with the popularization of computers, more and more digital controllers are used in the control of industrial systems, so the accuracy of system modeling is also required to be higher and higher. However, as a complex controlled object, various process control systems have various complex problems such as multiple input and multiple output, nonlinearity, strong coupling, and time delay. Therefore, the controller needs to have a strong control ability even in the presence of time delay and uncertainty in...

AI Technical Summary

Problems solved by technology

However, the high-speed sampling of the traditional shift operator will make the control performance of the discrete system worse, and even appear unstable.

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