The objective of this study is to identify system parameters from the recorded response of base isolated buildings,such as USC hospital building,during the 1994 Northridge earthquake.Full state measurements are not av...The objective of this study is to identify system parameters from the recorded response of base isolated buildings,such as USC hospital building,during the 1994 Northridge earthquake.Full state measurements are not available for identification.Additionally,the response is nonlinear due to the yielding of the lead-rubber bearings.Two new approaches are presented in this paper to solve the aforementioned problems.First,a reduced order observer is used to estimate the unmeasured states.Second,a least squares technique with time segments is developed to identify the piece-wise linear system properties.The observer is used to estimate the initial conditions needed for the time segmented identification.A series of equivalent linear system parameters are identified in different time segments.It is shown that the change in system parameters,such as frequencies and damping ratios,due to nonlinear behavior of the lead-rubber bearings,are reliably estimated using the presented technique.It is shown that the response was reduced due to yielding of the lead-rubber bearings and period lengthening.展开更多
In the process of signal transmission,an inevitable phenomenon is that the signal may change abruptly at certain discrete moments,negatively contributing to the performance of the system.In this paper,we focus on the ...In the process of signal transmission,an inevitable phenomenon is that the signal may change abruptly at certain discrete moments,negatively contributing to the performance of the system.In this paper,we focus on the distributed state estimation problem for continuous-time linear time-invariant(LTI)systems with intermittent abrupt jumps in communication information.First,the phenomenon of intermittent sudden jumps during information transmission is characterized as impulsive communication disturbances.Under impulsive communication disturbances,a distributed reduced order observer(DROO)is designed with each local observer grouped with two modules:a reduced-order observer and a consensus-based observer.Then,sufficient conditions for the existence of the DROO are presented,by using the graph theory and impulsive analysis.The relationship between the feedback gain and the unstable system matrix,the network topology,the impulse intensity,and the average impulsive interval is obtained.Finally,the validity of the proposed DROO under impulsive communication disturbances is substantiated by numerical simulations.展开更多
In this article, we establish the route taken by the author, and his research group, to bring differential flatness to the realm of active disturbance rejection control （ADRC）. This avenue entitled： 1） generalized...In this article, we establish the route taken by the author, and his research group, to bring differential flatness to the realm of active disturbance rejection control （ADRC）. This avenue entitled： 1） generalized proportional integral observers （GPIO）, as natural state and disturbance observers for fiat systems, 2） generalized proportional integral （GPI） control, provided with extra integrations, to produce a modular controller known as flat filters （FF＇s） and, finally, 3） the establishing of an equivalence of observer based ADRC with FF＇s. The context is that of pure integration systems. The obtained controllers depend only on the order of the flat system and they are to be directly used on the basis of the available flat output signal in a universal, modular, fashion. The map is complemented with the relevant references where the intermediate techniques were illustrated and developed, over the years, in connection with laboratory experimental implementations.展开更多
文摘The objective of this study is to identify system parameters from the recorded response of base isolated buildings,such as USC hospital building,during the 1994 Northridge earthquake.Full state measurements are not available for identification.Additionally,the response is nonlinear due to the yielding of the lead-rubber bearings.Two new approaches are presented in this paper to solve the aforementioned problems.First,a reduced order observer is used to estimate the unmeasured states.Second,a least squares technique with time segments is developed to identify the piece-wise linear system properties.The observer is used to estimate the initial conditions needed for the time segmented identification.A series of equivalent linear system parameters are identified in different time segments.It is shown that the change in system parameters,such as frequencies and damping ratios,due to nonlinear behavior of the lead-rubber bearings,are reliably estimated using the presented technique.It is shown that the response was reduced due to yielding of the lead-rubber bearings and period lengthening.
基金supported in part by the National Natural Science Foundation of China under Grant Nos.62425602 and 62273159
文摘In the process of signal transmission,an inevitable phenomenon is that the signal may change abruptly at certain discrete moments,negatively contributing to the performance of the system.In this paper,we focus on the distributed state estimation problem for continuous-time linear time-invariant(LTI)systems with intermittent abrupt jumps in communication information.First,the phenomenon of intermittent sudden jumps during information transmission is characterized as impulsive communication disturbances.Under impulsive communication disturbances,a distributed reduced order observer(DROO)is designed with each local observer grouped with two modules:a reduced-order observer and a consensus-based observer.Then,sufficient conditions for the existence of the DROO are presented,by using the graph theory and impulsive analysis.The relationship between the feedback gain and the unstable system matrix,the network topology,the impulse intensity,and the average impulsive interval is obtained.Finally,the validity of the proposed DROO under impulsive communication disturbances is substantiated by numerical simulations.
文摘In this article, we establish the route taken by the author, and his research group, to bring differential flatness to the realm of active disturbance rejection control （ADRC）. This avenue entitled： 1） generalized proportional integral observers （GPIO）, as natural state and disturbance observers for fiat systems, 2） generalized proportional integral （GPI） control, provided with extra integrations, to produce a modular controller known as flat filters （FF＇s） and, finally, 3） the establishing of an equivalence of observer based ADRC with FF＇s. The context is that of pure integration systems. The obtained controllers depend only on the order of the flat system and they are to be directly used on the basis of the available flat output signal in a universal, modular, fashion. The map is complemented with the relevant references where the intermediate techniques were illustrated and developed, over the years, in connection with laboratory experimental implementations.
