The Research On Internal Model Control For Complex Processes With Time Delays

In modern process industry, we often have to deal with some complex objects that contain time delay characteristics. Due to the presence of time delay, the output signal cannot feedback timely, and thus cannot give an effective and timely control action, so that deteriorating the effect of control.In addition to time delay, the complexity of the control plant also comes from the open loop stable, the multiple-input and multiple-output and complex internal coupling relationship of the plant. Therefore, this article selected internal model control as the main control scheme, study the implement of the internal model control in complex object described above.For delay unstable system, we proposed a modified two-degree of freedom control structure. In this structure, two controllers are individually designed for stabilization and disturbance rejection, so that the set point response and the anti-load disturbance can get a good result by completely decoupling and adjusting the parameters of the two controllers. Compared with the traditional two degrees of freedom control structure, this method is convenient in practice, in favor of industrial process applications. Offer an effective method for the delay and unstable control system.In the process of the study of the multi variable system, the multi variable system is divided into a square system and a non-square system. For multi variable systems, the decoupling internal model control scheme is adopted in this paper, which is to design the decoupling controller and the internal model controller in the design process. In the research of the system,the internal model control and static decoupling internal model control of the dynamic decoupling internal model control of the system are mainly studied.In addition to this method, a decoupling internal model control method based on singular value decomposition (SVD) is proposed, which uses the singular value decomposition to obtain the pre and post-matrix compensation matrix. The simulation results show that the proposed method can obtain good control performance and robustness. In the processing of the non-square system, the first study how to control the square of the non-square system. Then the decoupling control based on the generalized inverse direct to the non-square system is studied. In the end, the paper extends the method to the non-square system based on the SVD design of the pre - and post compensator. The simulation results show that the proposed method can obtain better performance and robustness in both square and non-square systems.