A frequency response analysis approach for quantitative assessment of actuator tracking for real-time hybrid simulation

Guo, Tong; Chen, Cheng; Xu, Weijie; Sanchez, Frank

doi:10.1088/0964-1726/23/4/045042

Cited by 32 publications

(28 citation statements)

References 30 publications

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“…This is also consistent with previous findings. 21 The WFEI method however is also observed to correct the estimated error in time delay between 3 and 12 s when the noise-to-signal ratio is higher. Figure 18 presents the time histories of α and TI for RTHS-1, RTHS-4, and RTHS-5 with the window length of 1,024, 512, and 2,048, respectively.…”

Section: Discussion Of Rths Resultsmentioning

confidence: 97%

“…Identifying the instantaneous delay due to servo-hydraulic dynamics is difficult, if not impossible. Guo et al 21 proposed a frequency-domain evaluation index (FEI) to estimate actuator delay, which is defined as…”

Section: Formulation Of Wfei Compensation Methodsmentioning

confidence: 99%

“…Various criteria have been proposed for actuator tracking assessment such as the maximum tracking error (MTE), root-mean-square (RMS) of the tracking error, tracking indicator (TI), 18 energy error (EE), 19,20 and frequency evaluation index (FEI). 21,22 To negate the time delay in RTHS, a predicted displacement is sent to actuator instead of the calculated displacement from the integration algorithm. This predicted displacement is often computed based on previous calculated displacements and estimated delay, such as polynomial extrapolation method 23 and the linear acceleration extrapolation, 24 wherein the former extrapolation is obtained through polynomial fitting and the latter calculates the prediction under the assumption of linear variation of structural acceleration response.…”

Section: Introductionmentioning

confidence: 99%

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Experimental verification of a frequency domain evaluation index‐based compensation for real‐time hybrid simulation

Guo

Chen

et al. 2020

Struct Control Health Monit

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Delay compensation method plays an important role in maintaining the stability and accuracy of the real-time hybrid simulation (RTHS). Inverse compensation (IC) method establishes a first-order discrete transfer function model to represent servo-hydraulic dynamics and provides an easy-to-implement compensation for RTHS. Only one parameter is required for the IC method, and it can be adjusted through different adaptive laws to accommodate error in initial delay estimation or time-varying delay throughout the test. Different techniques have been developed to improve the performance of the IC method such as dual compensation and adaptive IC (AIC). A windowed frequency domain evaluation index-based (WFEI) compensation is experimentally verified in this study through predefined tests and RTHS of a single-degree of freedom (SDOF) system. The frequency domain evaluation index (FEI) is applied through short-time Fourier transform (STFT) to estimate actuator delay in a real-time manner and to adapt the parameter of IC method to minimize possible delay variation and/or inaccurate estimation. The efficacy and robustness of the FEI-based compensation is further compared with the AIC method for various initial estimates, different window lengths, and bounds of estimated delay. Experimental results demonstrated that the WFEI method provides an effective and easy-to-implement method for RTHS.

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Section: Discussion Of Rths Resultsmentioning

confidence: 97%

Section: Formulation Of Wfei Compensation Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental verification of a frequency domain evaluation index‐based compensation for real‐time hybrid simulation

Guo

Chen

et al. 2020

Struct Control Health Monit

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“…In Civil engineering, dynamic substructuring is an experimental method that fuses numerical modelling techniques with laboratory testing to evaluate the response of complex structural systems to dynamic loading (e.g. Guo et al (2014) and Nakata (2011)). The unpredictable component of the system -the substructure -is tested physically in the laboratory using a transfer system.…”

Section: Introductionmentioning

confidence: 99%

The performance of delay compensation in real-time dynamic substructuring

Tang

Dietz

et al. 2017

Journal of Vibration and Control

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Real-time dynamic substructuring (RTDS) is a state-of-the-art experimental technique for evaluating the dynamic performance of a structural system subjected to time-varying loads in civil engineering. The accuracy and stability of RTDS is affected by the natural dynamics of the constituent transfer system. Of various control strategies, and due to the merits of simple implementation and low computational cost, delay-compensation methods have become most pervasive. In this paper, the performance of delay compensation based methods for RTDS is assessed in terms of accuracy and stability. Three commonly-used delay compensation schemes are considered: two time variant and one time invariant. Stability is assessed analytically, numerically and experimentally. Accuracy is assessed numerically and experimentally. To provide a suitable test for the delay compensation control schemes, a shaking table is adopted as the RTDS transfer system. It is demonstrated numerically, analytically and experimentally that when applied to transfer systems such as these, delay compensation can work to the detriment of test accuracy and test stability. Adequate performance of delay compensated, shaking-table based RTDS is confined a narrow low frequency bandwidth which severely restricts the range of potential application.

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“…Since the introduction of the RTHS, there has been a continuous effort on development and implementation of proper methods to assess the success of the simulation results. Current methods for estimation of local response error such as the tracking error (i.e., the difference between the command and measured displacements) usually use time domain properties [7], cumulative growth of energy errors [8], synchronization subspace plots [9,10] or the frequency domain response of the signals [11] to develop error monitors and indicators.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Integration Algorithms for Real-Time Hybrid Simulation Using Frequency Domain-Based Error Indicators

Hessabi¹,

Ashasi-Sorkhabi²,

Liu³

et al. 2015

Proceedings of the 5th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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Real-time hybrid simulation (RTHS) is a testing method that combines computer simulation (i.e., analytical substructure) with physical testing (i.e., experimental substructure). This enables investigation of dynamic characteristics of load-rate dependent complex structures. To ensure reliable experimental results, even in the presence of sophisticated controllers and compensation methods, it is necessary to evaluate the accuracy of the success of the hydraulic actuators in imposing the command displacements. With recent developments in tracking error monitoring, new indicators have been proposed that are based on frequency domain analysis and can successfully uncouple phase (lag and lead) and amplitude (overshoot and undershoot) errors and quantify them. These new frequency-based error indicators are not structure-specific and can be reliably used to examine the effectiveness of each component of RTHS inner (i.e., servo-control) and outer (i.e., integration algorithm) loops. In this paper, frequency domain-based (FDB) error indicators are employed to evaluate the effectiveness of five commonly-used integration algorithms (i.e. central difference method, explicit Newmark method, discrete state space formulation with a zero-order hold and first-order hold, the state-space formulation by Zhang et al., and the alpha method) in different test scenarios. The applicability of the FDB error indicators to nonlinear systems is first verified through numerical simulations performed on a nonlinear system with predefined parameters. Then these indicators are used to post-process the experimental results obtained from RTHS's with various integration algorithms. The experiments are carried out on a system with a nonlinear analytical substructure and a linear experimental substructure at the University of Toronto. Findings from numerical simulation and experimental results demonstrate that the FDB method is an efficient approach to compare performances of different integration algorithms.

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A frequency response analysis approach for quantitative assessment of actuator tracking for real-time hybrid simulation

Cited by 32 publications

References 30 publications

Experimental verification of a frequency domain evaluation index‐based compensation for real‐time hybrid simulation

Experimental verification of a frequency domain evaluation index‐based compensation for real‐time hybrid simulation

The performance of delay compensation in real-time dynamic substructuring

Comparison of Integration Algorithms for Real-Time Hybrid Simulation Using Frequency Domain-Based Error Indicators

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