Control Strategy Research On Replicate In Time Domain Of Earthquke Simulation Shaker

The earthquake is the major disasters in human society, replicate test in time domain on earthquake simulation shaker is the more real earthquake simulation test, which is the most direct and accurate test method of the study of seismic performance. Earthquake simulation test have the following characteristics:frequency response function (FRF) of pay load tend to change in certain condition, lower frequency limit of simulation test is very low, system identification can cause damage to payload. The current control system cannot reach the above target, so it is necessary to study the servo control system and vibration control system of’earthquake simulation test.In order to study the strategy of earthquake simulation control, this paper constructs a single-degree-freedom shaker and a multi-degree-freedom shaker. On this basis, analysis the principal of the digital servo control system and vibration control system, study the verification method of shaker, verification results show that the two systems can get high accuracy under the rigid payload.Because the hydraulic system with a small damping ratio and a low natural frequency, so the pole placement method of the three variable control (TVC) is needed to correct the FRF of shaker. The TVC apply to elastic payload can cause instability of the shaker system. An improved servo control is proposed which realize the TVC apply to elastic payload, optimize the acquirement of initializing FRF of shaker, and overcome the friction using adaptive backstepping control based on LUGRE model. The simulation and experiment verify the effectiveness of the proposed control.To improve the accuracy of the earthquake simulation test, identification accuracy must be improved, based on analysis of time domain and frequency domain identification method, Hv is adopted in this paper to acquirement the FRF of shaker; because the coupling of the payload with shaker can produce the ill-condition FRF matrix, this paper analysis the principal of ill-condition and its influence on the control accuracy, the pseudo rank can produce rank approximation, which can control the damage of ill-condition of FRF matrix, The simulation verify the effectiveness of the proposed control.Earthquake simulation replication test in time domain can produce much error in low frequency range, while in the elastic-plastic stage of specimen, rapid changes of FRF can result in lower control precision. This paper put forward multi-movement parameters replication control, which improve the control precision in low frequency range by realizing acceleration iterative learning’control and displacement iterative learning control, and put forward rapid iterative learning control which improve the response based on high accuracy of control. The experiments verify the effectiveness of the proposed control.In the process of multi-degree-freedom earthquake test, the FRF of system cannot be update, while the FRF of system change rapidly because payload in the elastic-plastic stage, so the system tend to instability. This paper puts forward the improved control which estimates the FRF in experiment, certain the frequency range of instability, update the FRF of this frequency range, and update the drive signal. The simulation and experiment verify the effectiveness of the proposed control.