Direct Acceleration Feedback Control of Shake Tables with Force Stabilization

Stehman, Matthew; Nakata, Narutoshi

doi:10.1080/13632469.2013.776508

Cited by 42 publications

(28 citation statements)

References 11 publications

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“…Since shake tables use hydraulic actuators to produce motion, this compatibility requires high performance acceleration tracking of shake tables. While this is a challenging issue, there has been significant progress in the enhancement of acceleration tracking of shake tables [namely: Stehman and Nakata (2012) and Phillips et. al.…”

Section: Compatibility Conditions For Dynamic Equivalencementioning

confidence: 99%

Substructure Shake Table Testing with Force Controlled Actuators

Nakata

Stehman

2014

Structures Congress 2014

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Real-time hybrid simulation (RTHS) has emerged as a feasible and economical means for seismic performance assessment of structural systems. It has been successfully applied to study the system-level response, combining experimental and computational substructures. However, existing substructure techniques are limited to interface boundaries where the influence of unbalanced forces are not significant; because existing formulation procedures and experimental loading are both displacement-based, unbalanced forces are inevitable in conventional RTHS. In some cases (e.g., testing of extremely rigid specimens, soil-structure boundaries), force equilibrium becomes more critical than displacement compatibility. To accommodate such conditions, a force-based approach is essential and has to be developed in RTHS. This study presents substructure shake table testing as a case study of forcebased RTHS. A four-story shear structure is divided into two substructures. The first story is tested on a shake table while the rest of the structure is computationally simulated. The interaction between the experimental and computational substructures is addressed such that the measured acceleration at the top floor in the experimental substructure is used as the base input to the computational structure while computed base shear in the computational substructure is fed back to the experimental substructure through a force-controlled actuator. As such, the overall simulation is performed at real-time with force-controlled actuators. This study presents the underlying theories of the substructure shake table test method, centralized actuator control and preliminary numerical simulations.

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Section: Compatibility Conditions For Dynamic Equivalencementioning

confidence: 99%

Substructure Shake Table Testing with Force Controlled Actuators

Nakata

Stehman

2014

Structures Congress 2014

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“…In this paper, the sliding surface, S, shown in Equation (6), is defined as a linear combination of the displacement tracking error by Equation (7) and velocity tracking error by Equation (8). Then, the feedback control law should be determined so that the trajectory of a system in the state space will be able to intersect and be confined on the sliding surface.…”

Section: Design Of High-level Controllermentioning

confidence: 99%

Development of high‐performance shake tables using the hierarchical control strategy and nonlinear control techniques

Yang

Lin

et al. 2015

Earthq Engng Struct Dyn

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Summary Conventional shake tables employ linear controllers such as proportional‐integral‐derivative or loop shaping to regulate the movement. However, it is difficult to tune a linear controller to achieve accurate and robust tracking of different reference signals under payloads. The challenges are mainly due to the nonlinearity in hydraulic actuator dynamics and specimen behavior. Moreover, tracking a high‐frequency reference signal using a linear controller tends to cause actuator saturation and instability. In this paper, a hierarchical control strategy is proposed to develop a high‐performance shake table. A unidirectional shake table is constructed at the University of British Columbia to implement and evaluate the proposed control framework, which consists of a high‐level controller and one or multiple low‐level controller(s). The high‐level controller utilizes the sliding mode control (SMC) technique to provide robustness to compensate for model nonlinearity and uncertainties experienced in experimental tests. The performance of the proposed controller is compared with a state‐of‐the‐art loop‐shaping displacement‐based controller. The experimental results show that the proposed hierarchical shake table control system with SMC can provide superior displacement, velocity and acceleration tracking performance and improved robustness against modeling uncertainty and nonlinearities. Copyright © 2015 John Wiley & Sons, Ltd.

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“…Their main objective is to replicate a wide range of a desired motion with a high degree of accuracy, in order to generate meaningful and reliable results. However, despite the significant progress achieved in shake table design and control technology during the last decades, number of challenges still exist [2]. These challenges fall into two categories: (i) economical and practical challenges and (ii) technical challenges.…”

Section: Introductionmentioning

confidence: 99%

Performance of the CGS six DOF Shaking Table on the Harmonic Signal Reproduction

Halim

Airouche

Hassan

et al. 2017

Period. Polytech. Civil Eng.

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IntroductionShaking tables are being increasingly used in earthquake engineering research field and remain one of the preferred tools for seismic testing [1]. Their main objective is to replicate a wide range of a desired motion with a high degree of accuracy, in order to generate meaningful and reliable results. However, despite the significant progress achieved in shake table design and control technology during the last decades, number of challenges still exist [2]. These challenges fall into two categories: (i) economical and practical challenges and (ii) technical challenges. In the first category we can cite the problem of the full-scale realistic tests of large structural systems which are constrained by the limited financial resources and capacities of the existing laboratories. The second category includes control issues, consideration of different loading conditions other than dynamic base motion and soil-structure interaction effects in shaking-table testing.Undoubtedly, the control of shaking table is the key element of the whole system and one of the most difficult technical challenges. In fact, the modern multiple degree-of-freedom shaking table with a resonating and eccentric specimen has the characteristics of a strongly coupled multiple input, multiple output dynamic system [3]. In such a system, servovalves characteristics, oil column resonance, frictions in the system, cross coupling between degrees of freedom, specimen compliance and noise in feedback transducers, are some of the predominant sources of nonlinearities that can adversely affect the accurate control, stability and high fidelity signal reproduction, of the shaking table.Various control techniques have been developed in order to provide a shaking table with optimum performance and high level of motion control. The earliest methods use conventional linear controller, such as closed-loop PID, deltaP and feed-forward control algorithm [4,5], and three variable control (TVC) [6,7]. However, due to the complexity of the problem the need for more sophisticated control systems become necessary. With advances in computing technologies, followed by the breakthrough development of the digital signal processing and realtime operations, methods based on hybrid control strategies

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Direct Acceleration Feedback Control of Shake Tables with Force Stabilization

Cited by 42 publications

References 11 publications

Substructure Shake Table Testing with Force Controlled Actuators

Substructure Shake Table Testing with Force Controlled Actuators

Development of high‐performance shake tables using the hierarchical control strategy and nonlinear control techniques

Performance of the CGS six DOF Shaking Table on the Harmonic Signal Reproduction

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