Research On Robust Predictive Control For Multi-phase Batch Processes With Asynchronous Switching

Multi-phase batch processes such as food processing,biopharmace-uticals,and polymer production occupies an important position in industrial production processes.With the increasing complexity of multi-phase batch processes and stricter requirements on product quality,traditional control methods can no longer meet the process requirements,and there is an urgent need for a control that can effectively deal with multi-phase batch processes with complex characteristics.method.Based on previous research work,this paper conducts a more in-depth study on a kind of robust model predictive control method for multi-phase batch processes with asynchronous switching characteristics.The main research work is summarized as follows:(1)Briefly introduced the background and significance of the research on multi-phase batch processes control;reviewed in detail the domestic and foreign research status of multi-phase batch processes control,pointed out the current problems and shortcomings of the current multi-phase batch process control.Based on this,the main research content of this article is put forward.(2)A robust asynchronous switching model predictive controller is designed for multi-phase batch processes with uncertainties,unknown disturbances and time-varying set-point.Firstly,in view of the influence of time-varying set-point and disturbances,an asynchronous switching model with stable and unstable cases is established.Based on the switching model,a robust asynchronous switching model predictive control law is designed.Secondly,by using relevant theories and methods,the sufficient conditions with the form of linear matrix inequality(LMI)are given to ensure that the multi-phase batch processes are asymptotically stable at each phase and exponentially stable at each batch.Then,these LMI conditions are solved online to obtain the control gain of each phase,the shortest running time of each stable case,and the longest running time of each unstable case.Finally,the effectiveness and feasibility of the proposed method are verified by taking the injection molding process as an example.(3)A robust asynchronous switching fault-tolerant control method is proposed to solve the problems of uncertainties,unknown disturbances,time-varying delays and partial actuator failures in multi-phase batch processes.Firstly,an asynchronous system composed of subsystems with different dimensions including stable and unstable case is established to describe such multi-phase batch processes more accurately.Then introducing the output tracking error,the established switching model of different dimensions is extended.On this basis,a robust asynchronous switching fault-tolerant control law is designed,which improves the system's ability to cope with negative factors such as actuator failure and can obtain greater adjustment freedom.Secondly,by using relevant theories and methods,the sufficient conditions in the form of linear matrix inequality(LMI)are given to ensure the exponential stability of the system and the asymptotic stability at each phase.By solving these LMIs conditions,the shortest running time under stable case,the longest running time under unstable case and the control law gain of each phase are obtained.Finally,the effectiveness and feasibility of the proposed method are verified with injection molding process.