scholarly journals Mixed Sensitivity-Based Robust H∞ Control Method for Real-Time Hybrid Simulation

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 840
Author(s):  
Xizhan Ning
Keyword(s):  
Real Time ◽  
Control Method ◽  
Weighting Function ◽  
Hybrid Simulation ◽  
Shaking Table ◽  
Transfer System ◽  
Hydraulic Actuator ◽  
Earthquake Excitation ◽  
Engineering Structures ◽  
Weighting Functions

Real-time hybrid simulation (RTHS), dividing the emulated structure into numerical substructures (NS) and physical substructures (PS), is a powerful technique to obtain responses and then to assess the seismic performance of civil engineering structures. A transfer system, a servo-hydraulic actuator or shaking table, is used to apply boundary conditions between the two substructures. However, the servo-hydraulic actuator is inherently a complex system with nonlinearities and may introduce time delays into the RTHS, which will decrease the accuracy and stability of the RTHS. Moreover, there are various uncertainties in RTHS. An accurate and robust actuator control strategy is necessary to guarantee reliable simulation results. Therefore, a mixed sensitivity-based H∞ control method was proposed for RTHS. In H∞ control, the dynamics and robustness of the closed-loop transfer system are realized by performance weighting functions. A form of weighting function was given considering the requirement in RTHS. The influence of the weighting functions on the dynamics was investigated. Numerical simulations and actual RTHSs were carried out under symmetric and asymmetric dynamic loads, namely sinusoidal and earthquake excitation, respectively. Results indicated that the H∞ control method used for RTHS is feasible, and it exhibits an excellent tracking performance and robustness.

scholarly journals Implementation of Real Time Hybrid Simulation Based on GPU Computing

2021 ◽  
Author(s):  
Zhenyun Tang ◽  
Xiaohui Dong ◽  
Zhenbao Li ◽  
Xiuli Du
Keyword(s):  
Real Time ◽  
Degrees Of Freedom ◽  
Gpu Computing ◽  
Dynamic Performance ◽  
Hybrid Simulation ◽  
Shaking Table ◽  
Processing Unit ◽  
Engineering Structures ◽  
Element Analysis ◽  
Complex Engineering

Abstract With combination of physical experiment and numerical simulation, real-time hybrid simulation (RTHS) can enlarge the dimensions of testing specimens and improve the testing accuracy. However, due to the limitation of computing capacity, the maximum degrees of freedom for numerical substructure are less than 2000 from the reported RTHS testing. It cannot meet the testing requirements for evaluating the dynamic performance of large and complex engineering structures. Taking advantages of parallel computing toolbox (PCT) in Matlab and high-performance computing of graphics processing unit (GPU). A RTHS framework based on MATLAB and GPU was established in this work. Using this framework, a soil-structure interaction system (SSI) was tested by a shaking table based RTHS. Meanwhile, the dynamic response of this SSI system was simulated by finite element analysis. The comparison of simulation and testing results demonstrated that the proposed testing framework can implement RTHS testing successfully. Using this method, the maximum degrees of freedom for numerical substructure can reach to 27,000, which significantly enhance the testing capacity of RTHS testing for large and complex engineering structures.

scholarly journals Implementation of Real Time Hybrid Simulation Based On GPU Computing

2021 ◽  
Author(s):  
Zhenyun Tang ◽  
Xiaohui Dong ◽  
Zhenbao Li ◽  
Xiuli Du
Keyword(s):  
Real Time ◽  
Degrees Of Freedom ◽  
Gpu Computing ◽  
Dynamic Performance ◽  
Hybrid Simulation ◽  
Shaking Table ◽  
Processing Unit ◽  
Engineering Structures ◽  
Element Analysis ◽  
Complex Engineering

Abstract With combination of physical experiment and numerical simulation, real-time hybrid simulation (RTHS) can enlarge the dimensions of testing specimens and improve the testing accuracy. However, due to the limitation of computing capacity, the maximum degrees of freedom for numerical substructure are less than 7000 from the reported RTHS testing. It cannot meet the testing requirements for evaluating the dynamic performance of large and complex engineering structures. Taking advantages of parallel computing toolbox (PCT) in Matlab and high-performance computing of graphics processing unit (GPU). A RTHS framework based on MATLAB and GPU was established in this work. Using this framework, a soil-structure interaction system (SSI) was tested by a shaking table based RTHS. Meanwhile, the dynamic response of this SSI system was simulated by finite element analysis. The comparison of simulation and testing results demonstrated that the proposed testing framework can implement RTHS testing successfully. Using this method, the maximum degrees of freedom for numerical substructure can reach to 27,000, which significantly enhance the testing capacity of RTHS testing for large and complex engineering structures.

Feasibility study of an adaptive mount system based on magnetorheological elastomer using real-time hybrid simulation

2018 ◽  
Vol 30 (5) ◽  
pp. 701-707 ◽  
Author(s):  
Seung-Hyun Eem ◽  
Jeong-Hoi Koo ◽  
Hyung-Jo Jung
Keyword(s):  
Magnetic Field ◽  
Control System ◽  
Real Time ◽  
Control Algorithm ◽  
Vibration Reduction ◽  
Hybrid Simulation ◽  
Shaking Table ◽  
Magnetorheological Elastomer ◽  
Experimental Part ◽  
Hybrid Simulations

This article investigates an adaptive mount system based on magnetorheological elastomer in reducing the vibration of an equipment on the isolation table. Incorporating MR elastomers, whose elastic modulus or stiffness can be adjusted depending on the applied magnetic field, the proposed mount system strives to alleviate the limitations of existing passive-type mount systems. The primary goal of this study is to evaluate the vibration reduction performance of the proposed MR elastomer mount using the hybrid simulation technique. For real-time hybrid simulations, the MR elastomer mount and the control system are used as an experimental part, which is installed on the shaking table, and an equipment on the table is used as a numerical part. A suitable control algorithm is designed for the real-time hybrid simulations to avoid the responses of the equipment’s natural frequency by tracking the frequencies of the responses. After performing a series of real-time hybrid simulation on the adaptive mount system and the passive-type mount system under sinusoidal excitations, this study compares the effectiveness of the adaptive mount system over its passive counterpart. The results show that the proposed adaptive elastomer mount system outperforms the passive-type mount system in reducing the responses of the equipment for the excitations considered in this study.

scholarly journals Kalman Filter-Based Adaptive Delay Compensation for Benchmark Problem in Real-Time Hybrid Simulation

2020 ◽  
Vol 10 (20) ◽  
pp. 7101
Author(s):  
Xizhan Ning ◽  
Zhen Wang ◽  
Bin Wu
Keyword(s):  
Kalman Filter ◽  
Time Delay ◽  
Real Time ◽  
Control Plant ◽  
Hybrid Simulation ◽  
Time Varying ◽  
Transfer System ◽  
Benchmark Problem ◽  
Delay Compensation ◽  
Comparison Results

Real-time hybrid simulation (RTHS) is a versatile, effective, and promising experimental method used to evaluate the structural performance under dynamic loads. In RTHS, the emulated structure is divided into a numerically simulated substructure (NS) and a physically tested substructure (PS), and a transfer system is used to ensure the force equilibrium and deformation compatibility between the substructures. Owing to the inherent dynamics of the PS and transfer system (referred to as a control plant in this study), there is a time-delay between the displacement command and measurement. This causes de-synchronization between the boundary of the PS and NS, and affects the stability and accuracy of the RTHS. In this study, a Kalman filter-based adaptive delay compensation (KF-ADC) method is proposed to address this issue. In this novel method, the control plant is represented by a discrete-time model, whose coefficients are time-varying and are estimated online by the KF using the displacement commands and measurements. Based on this time-varying model, the delay compensator is constructed employing the desired displacements. The KF performance is investigated theoretically and numerically. To assess the performance of the proposed strategy, a series of virtual RTHSs are performed on the Benchmark problem in RTHS, which was based on an actual experimental system. Meanwhile, several promising delay-compensation strategies are employed for comparison. Results reveal that the proposed time-delay compensation method effectively enhances the accuracy, stability, and robustness of RTHS.

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