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Chen Y.,Zhejiang University | Luan Q.L.,Zhejiang University | Chen Z.W.,Zhejiang University | He H.N.,Hangzhou ECON Science and Technology Co.
Applied Mechanics and Materials | Year: 2014

Hydraulic shaker, equipment of simulating laboratory vibration environment, can accurately replicate the given power spectral density (PSD) and time history with an appropriate control algorithm. By studying method Hv estimator of frequency response function (FRF) estimation, a FRF identification strategy based on the Hv estimator is designed to increase the convergence rapidity and improve the system response function specialty. The system amplitude-frequency characteristics in some frequency points or frequency bands have large fluctuation. To solve this issue, a step-varying and frequency-sectioning iterative correction control algorithm is proposed for the control of 2-axial exciter PSD replication tests and the results show that the algorithm has a good effect on the control of hydraulic shaker, and can achieve reliable and high-precision PSD replication. © (2014) Trans Tech Publications, Switzerland.


Luan Q.-L.,Zhejiang University | Chen Z.-W.,Zhejiang University | He H.-N.,Hangzhou ECON Science and Technology Co.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2014

The control strategy for a hydraulic shaker controlled with a 3-stage electro-hydraulic servo valve was studied here. An integrated controller was designed for a large-flow hydraulic shaker. The controller could simultaneously realize servo control and vibration control functions of the hydraulic shaker. In the process of the servo control, a dual-PID servo-control strategy was presented for the 3-stage electro-hydraulic servo valve and the servo cylinder. In the process of the vibration control, aiming at the good low-frequency characteristics of the hydraulic shaker, a waveform replication method based on a closed-loop iterative control was designed. Through the waveform replication tests with different time histories and different bandwidths on the hydraulic shaker controlled with the integrated controller, it indicated that the controller has a strong waveform control ability to achieve a high-precision waveform replication on the hydraulic shaker. ©, 2014, Chinese Vibration Engineering Society. All right reserved.


Luan Q.-L.,Zhejiang University | Chen Y.,Zhejiang University | Chen Z.-W.,Zhejiang University | He H.-N.,Hangzhou ECON Science and Technology Co.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2015

Through discussing aseismic test technique for telecommunication equipments, the aseismic test method for GR-63-CORE criteria of NEBS (network equipment-building system) was studied. For the problems that the system bandwidth was not enough and there existed the effects of nonlinear factors, a TVC (three-variable control) algorithm for servo control of a seismic simulation shaking table was designed, and a correction iteration algorithm in frequency domain for the driving signal correction of the shaking table was proposed. The research results showed that the TVC algorithm can effectively be used to expand the bandwidth of the test system and improve its dynamic response range; and the correction iteration algorithm can effectively be used to compensate the influences of the nonlinear factors on the test system by on-line correcting the driving signal iteratively. The aseismic tests of NEBS GR-63-CORE showed that with the control strategies of the TVC algorithm and the correction iteration algorithm, the shaking table can realize seismic waveform replication tests precisely. ©, 2015, Chinese Vibration Engineering Society. All right reserved.


Wang H.-D.,Shanghai Spaceflight Precision Machinery Institute | Luan Q.-L.,Zhejiang University | Chen Z.-W.,Zhejiang University | He H.-N.,Hangzhou ECON Science and Technology Co.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2015

Through studying the control algorithm for multi-exciter PSD (power spectral density) replication vibration tests, an identification strategy for the frequency response matrix of a vibration test system based on partial coherence analysis was designed. For situations of singular points existing in a system frequency response matrix and the matrix being rectangular, different system decoupling algorithms were desgined based on the solutions to the matrix generalized inverse and its Moore-Penrose inverse with the minimum norm and least square methods. Aiming at the situation that the system APSD (auto-power spectral density) might be negative or zero in the traditional difference correction of the drive spectral control algorithm, an improved PSD equalization control strategy was designed by introducing a proportional RMS feedback correction algorithm. The algorithm could effectively avoid the APSD being negative and zero in the process of PSD equalization. The multi-exciter PSD replication vibration tests showed that the improved PSD equalization control strategy can achieve a reliable, high-precision control effect on a multi-exciter vibration system. ©, 2015, Chinese Vibration Engineering Society. All right reserved.


Luan Q.-L.,Zhejiang University | Chen Z.-W.,Zhejiang University | Xu J.-R.,Zhejiang University | He H.-N.,Hangzhou ECON Science and Technology Co.
Zhendong Gongcheng Xuebao/Journal of Vibration Engineering | Year: 2014

A fast three-variable parameter tuning method was presented through the research on three-variable control (TVC) and its parameter tuning technology on seismic simulation shaking tables. Through the investigation of the three-variable control algorithm, the analytical expressions of parameters in three-variable feedback and feedforward loops are derived, achieving the parameter tuning of the three-variable controller, which greatly improved the efficiency of three-variable parameter tuning process for seismic simulation shaking tables. Finally, comparison between the traditional three-variable control parameter tuning method and the fast three-variable control parameter tuning method in the simulation and field test further shows the effectiveness and high efficiency of the fast three-variable control parameter tuning method.


Luan Q.-L.,Zhejiang University | Chen Z.-W.,Zhejiang University | Xu J.-R.,Zhejiang University | He H.-N.,Hangzhou ECON Science and Technology Co.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2014

Three-variable control (TVC) algorithm for a seismic analog shaking table was studied deeply, and the correction action of the three-variable feedback and the three-variable feedforward step on the characteristics of the shaking table system was investigated in detail. Through simulation and field tests, the improvement effect of the three-variable control technique on the system frequency response characteristics of the seismic analog shaking table was verified. The system frequency bandwidth was expanded effectively by introducing the velocity feedback of TVC. The system damping was raised by introducing the acceleration feedback of TVC. The pole points of the system closed-loop transfer function close to the imaginary axis were eliminated and the system bandwidth was further extended by introducing the three-variable feedforward control. Finally, by conducting the seismic wave reproduction test on a three-variable controlled shaking table, it was shown that the TVC algorithm can realize a higher-precision seismic wave reproduction test.

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