Research On Robust Control Of PCHD Systems

The magnetic levitation system is a complex nonlinear system,especially under the influence of uncertain factors such as external disturbance and model error,it is more difficult to control it stably.Therefore,it is necessary to find a good control algorithm to make the magnetic levitation system more robust to various uncertainties and external disturbances.In this paper,the magnetic suspension bearing system is taken as the research object,which is transformed into PCHD(Port-Controlled Hamiltonian with Dissipation,PCHD)system by modeling,and combined with the robust control method based on operator theory for analysis and control research.Robust right coprime factorization based on operator theory is a new practical control algorithm.It has great advantages in dealing with the inverse and stability of operators and control problems of systems with uncertainties.Firstly,this paper introduces the research background and significance of the magnetic levitation system,and then introduces operator theory,robust right coprime factorization based on operator theory,right coprime factorization method based on isomorphism,and robust passive control method and other methods.At the same time,passivity-based control makes the research problem more physically,because it only needs to consider the energy variation of the system to control.Therefore,this paper combines passivity-based control and robust right coprime factorization method to study the modeling and robust control of the magnetic suspension bearing system,the specific scheme is as follows:Starting from the energy perspective of the system,passivity-based control theory is introduced into right coprime factorization method based on the operator theory,and a robust control method based on passive theory is proposed.By seeking the relationship between the energy function related to the controlled quantity and the Bezout identity,the robust passive controller is designed to make the system robust and stable,and the effectiveness of the method is verified by simulation.In view of the robust control problem of magnetic suspension bearing system,this paper proposes three schemes.Firstly,according to the linearization model of the magnetic suspension bearing system,a robust_?controller is presented.The simulation shows the good stability performance and robust performance of system.Moreover,based on operator theory,two design schemes are given:one is to transform the linearized model into a model of operator,and the bearing system is robustly controlled by right coprime factorization based on operator theory;Secondly,according to the nonlinear model of the magnetic suspension bearing system,the PCHD model is derived and the robust passive control scheme is implemented.