Synthesis Of System Identification And Vibration Control For Smart Structures

Smart structure has been widely studied and developed in recent years.Both the health monitoring system and the vibration control system are equipped with sensors,data processing and actuators,just like the nervous system,brain and muscle tissue of the human body.When the sensors obtain the information of external extreme load,it will transmit the data to the processing system to calculate the optimal control force required by the structure at this time,and then feed the data to the actuator,which performs the optimal control on the structure.The mechanism is similar to the way that the nerves of body sense an external stimulus,and the brain processes to get the muscles to respond appropriately.This structure with intelligent functions becomes an smart structure.This smart structure has the advantages of economy and efficiency.Therefore,based on this background,this paper mainly studies the integrated method of health monitoring and vibration control for smart structure.This paper is mainly based on the generalized extended Kalman filter(GEKF-Ul)method with unknown input proposed by the research group,aiming to solve the problems and limitations existing in the previous research on the integration of structural health monitoring and vibration control.In this paper,the system identification and vibration control of time-invariant system,time-varying system,AMD/SAMD-structure system and high-rise wind-induced structure are studied respectively.On the premise of outstanding contributions of corresponding scholars,some improvements are made to make the method more suitable for practical engineering applications.In the second chapter,an innovative integration method of health monitoring and semi-active control for time invariant systems is proposed.Compared with the latest existing research,the method proposed in this chapter has the advantages of only partial response observation and no response at the observation excitation,which makes the method have no special requirements for the placement of sensors,so it has stronger applicability.At the same time,the relative acceleration response of the structure cannot be obtained when the absolute acceleration response of the structure is observed under the condition that the ground motion is unknown.However,the relative acceleration response has been taken as the observed value in previous studies on system identification of unknown ground excitation,but this point has been ignored.To solve this problem,this chapter proposes a GEKF-UI algorithm based on the observation of absolute acceleration response and inter-layer displacement response to identify the system state and unknown ground motion,and at the same time,the combination of linear quadratic Gaussian control(LQG)algorithm and the corresponding semi-active control strategy for the intelligent control of the structure.On the basis of the previous chapter,the third chapter of this paper extends the method to the system identification and vibration control of high-rise structures.It not only identifies the main structure parameters,but also identifies the control equipment parameters embedded in the building to ensure the reliability of control effect.whenAMD/SAMD is installed inside the building and during service,its parameters and control performance may change,thus failing to achieve the optimal control effect.Theref'ore,the parameter identification of AMD/SAMD-structure system to ensure its control performance has been widely studied.The improvement of the method proposed in this chapter and the present method lies in that the parameters of AMD/S AMD-structure system can be identified and its control effect can be guaranteed under the premise of partial response observation.Based on the contents of the second and third chapters of this paper,considering the time-varying damage that may occur to the structural parameters when the building structure is in service in the fourth chapter,a method combining the system identification and adaptive semi-active control for this time-varying system is innovatively proposed.In the existing literature,time-varying systems are usually identified by solving complex nonlinear matrix equations about adaptive factors.However,it takes much time to solve the complex nonlinear matrix equation,which makes it difficult to combine with the control system that requires high time consumption.To solve this problem,based on the GEKF-UI method,the method in this chapter regards the time-varying term in the nonlinear system as a virtual unknown force.Through this transformation,the state recognition of the time-varying system can be truly 'real-time',so as to facilitate the combination with the semi-active control algorithm.In the first four chapters of this paper,the integrated method is studied in the form of earthquake action or concentrated load.In the fifth chapter,the method is extended to the form of distributed load,such as wind load,Therefore,this chapter proposes an innovative wind load identification method based on modal kalman filter under unknown input(MKF-UI),and controls the vibration of wind-induced structures.In the existing research,there have been some problems in the identification method of wind load that have not been solved,such as:the need to respond to full observation,unable to achieve real-time online,etc..However,the control of wind-induced structures usually requires wind load information,which is difficult to obtain in practice.Therefore,this chapter proposes a real-time and online identification of wind load under the condition of partial response observation,and meanwhile provides the optimal control force for the structure.