Research On Remaining Useful Life Prediction And Life Extension Of Feedback Control System Under Actuator Degradation

With the high-quality development of intelligent manufacturing-related technologies,the control system is becoming more complex and intelligent in the process of organically integrating the new generation of sensing technology and information technology.Control system life prediction and health maintenance(Prognostic and Health Management,PHM)has been given new connotation under the background of new technology.The safety,durability,and reliability have received unprecedented attention,and its performance and safety management of related equipment have become the focus of the enterprise.Although there have been many achievements in the PHM technology of single component or equipment,there is still a relative lack of research on the life prediction and health maintenance of the feedback control system.Based on this,this research starts with the construction of the life prediction and life extension control framework of the feedback control system,and under this framework,it focuses on implicit actuator degradation modeling,feedback control system failure threshold determination,remaining life prediction and system online life extension autonomous maintenance Related research.Its main work includes:1)Construction of the life prediction and life extension control framework of the feedback control system under the implicit degradation of the actuatorConsidering the connection and difference between the implicit actuator degradation and system degradation in the feedback control system,this research analyzes the intrinsic characteristics of the existing degradation modeling,life prediction and condition-based maintenance,builds the life prediction and life extension of the feedback control system Control framework.The framework intuitively presents the correlation between actuator degradation and control system,establishes a more complete system failure threshold judgment criterion,analyzes the mechanism of adjustable controller parameters to relieve actuator pressure,and develops life expectancy for feedback control systems.It laid the foundation for the life prediction and life extension control of the feedback control system.2)Research on Life Prediction and Life Extension of Feedback Control System Based on Gamma ProcessConsidering that the Gamma process has a certain advantage of describing the monotonous and regular degradation process,first of all,based on it,three modeling methods of actuator degradation and control system degradation with measurement errors and random impacts of actual degradation data are discussed;Secondly,based on the criteria of implicit degradation of the actuator and the judgment threshold of the system failure,a method for predicting the remaining life of the feedback control system is given;and then the parameters of the LQR controller are adjusted according to the real-time prediction of the remaining life of the system to delay the extension of the actuator System life.Finally,a single-capacity water tank system is used for simulation experiments.The results show that the composite degradation model of random impact and wear degradation is more in line with the actual degradation process.According to the system life prediction results obtained,the life extension control can better balance the control effect with system performance,the system life is effectively extended.3)Research on Life Prediction and Life Extension of Feedback Control System Based on Wiener ProcessConsidering that the actuator degradation process may not be strictly monotonous,based on the Wiener process,this research discusses three types of modeling methods for control system degradation under the influence of measurement errors and random shocks in the degradation data,The analytical solution of the life distribution of the feedback control system is obtained according to the judgment criterion of the performance constraint set.At the same time,an adaptive life extension strategy based on the real-time degradation state of the actuator(Adaptive Extending strategy)is proposed for the problem that the controller parameter adjustment is not related to the effective execution ability of the actuator.Through the simulation experiment in the double-capacity water tank system,the results show that the life prediction under the actuator degradation modeling method influenced by multiple factors is more in line with engineering reality,and AELCS-ODSA associates the degree of degradation with the controller parameter adjustment to relieve the actuator pressure.Targeted,it can also effectively extend the system running time.