Bond-graph based substructuring of dynamical systems

Gawthrop, P.J.; Wallace, Mark I.; Wagg, DJ

doi:10.1002/eqe.450

Cited by 15 publications

(29 citation statements)

References 29 publications

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“…Control Engineering Practice 16 (2008) [897][898][899][900][901][902][903][904][905][906][907][908] context of the related testing technique of real time dynamic substructuring (RTDS) Darby et al, 2002;Gawthrop et al, 2005b;Horiuchi et al, 1999;Reinhorn et al, 2004). The topic of real-time dynamic substructuring is the subject of a recent issue of Philosophical Transactions of the Royal Society, within which give an excellent introductory review.…”

Section: +44 (117) 929 4423mentioning

confidence: 99%

“…In a small number of cases, the dynamics of the transfer system can be removed from the closed loop by using an inverted model of the transfer system dynamics -for example, using the virtual actuator approach (Gawthrop, 2004(Gawthrop, , 2005Gawthrop et al, 2005b) -in most cases however, the transfer system is not (causally) invertible. One of the most commonly considered examples of a noninvertible transfer system is that of a pure time delay.…”

Section: +44 (117) 929 4423mentioning

confidence: 99%

“…Because the complete system being modelled is a physical system, each of the two subsystems has the special mathematical property of passivity (Willems, 1972) which can be expressed in bond graph terms (Gawthrop et al, 2005b). The software subsystem is connected to the hardware subsystem via a computer digital to analogue interface driving a physical actuator; the connection is referred to as the transfer system.…”

Section: Control Engineering Practice 16 (2008) 897-908 2 Actuator Bamentioning

confidence: 99%

“…This small phase margin gives rise to the extreme sensitivity problem discussed elsewhere (Gawthrop et al, 2005b(Gawthrop et al, , 2006Wallace et al, 2005b); in particular, a small value of c together with neglected dynamics in the transfer system results in…”

Section: Control Engineering Practice 16 (2008) 897-908mentioning

confidence: 99%

See 3 more Smart Citations

Emulator-based control for actuator-based hardware-in-the-loop testing

Gawthrop¹,

Virden²,

Neild³

et al. 2008

Control Engineering Practice

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Hardware-in-the-loop (HWiL) is a form of component testing where hardware components a linked with software models. In order to test mechanical components an additional transfer system is required to link the software and hardware subsystems. The transfer system typically comprises of sensors and actuators and the dynamic effects of these components need to be eliminated to give accurate results. In this paper an emulator-based control strategy is presented for actuator based HWiL. Emulator-based control can solve the twin problems of stability and fidelity caused by the unwanted transfer system (actuator) dynamics.Significantly EBC can emulate the inverse of a transfer system which is not causally invertible, allowing a wider range of more complex transfer systems to be controlled. A robustness analysis is given and experimental results presented.

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Section: +44 (117) 929 4423mentioning

confidence: 99%

Section: +44 (117) 929 4423mentioning

confidence: 99%

Section: Control Engineering Practice 16 (2008) 897-908 2 Actuator Bamentioning

confidence: 99%

Section: Control Engineering Practice 16 (2008) 897-908mentioning

confidence: 99%

See 2 more Smart Citations

Emulator-based control for actuator-based hardware-in-the-loop testing

Gawthrop¹,

Virden²,

Neild³

et al. 2008

Control Engineering Practice

View full text Add to dashboard Cite

show abstract

“…As pointed out previously [4,10], substructuring can be viewed as a control problem. However, unlike conventional control system design which aims for a well-damped closed-loop system, the corresponding substructuring design often has lightly-damped behaviour near the boundary of stability.…”

Section: Introductionmentioning

confidence: 99%

Robust real-time substructuring techniques for under-damped systems

Gawthrop¹,

Wallace²,

Neild³

et al. 2007

Struct. Control Health Monit.

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SUMMARYThis paper considers the hybrid simulation of under-damped dynamical systems using numerical-experimental real-time substructuring. Substructuring joins together a physical plant with a numerical model using real time control techniques, such that the combined model emulates the behaviour of the entire system. Due to the low damping, the control of substructured systems can be highly sensitive to delay and uncertainty. We present a technique for calculating the critical delay of the substructured system using a phase margin approach. In addition, it is shown that robustness techniques, drawn from feedback control theory, can be used to reduce the destabilizing effect of uncertainty. To demonstrate this a comparison of three different robustness compensators is presented, using a well known linear system. The level of uncertainty is deliberately increased to compare their performances and a discussion is made on when each may be most useful.

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Stability analysis of real‐time dynamic substructuring using delay differential equation models

Wallace

Sieber

Neild

et al. 2005

Earthq Engng Struct Dyn

169

163

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SUMMARYReal-time dynamic substructuring is an experimental technique for testing the dynamic behaviour of complex structures. It involves creating a hybrid model of the entire structure by combining an experimental test piece-the substructure-with a numerical model describing the remainder of the system. The technique is useful when it is impractical to experimentally test the entire structure or complete numerical modelling is insu cient.In this paper, we focus on the in uence of delay in the system, which is generally due to the inherent dynamics of the transfer systems (actuators) used for structural testing. This naturally gives rise to a delay di erential equation (DDE) model of the substructured system. With the case of a substructured system consisting of a single mass-spring oscillator we demonstrate how a DDE model can be used to understand the in uence of the response delay of the actuator. Speciÿcally, we describe a number of methods for identifying the critical time delay above which the system becomes unstable.Because of the low damping in many large structures a typical situation is that a substructuring test would operate in an unstable region if additional techniques were not implemented in practice. We demonstrate with an adaptive delay compensation technique that the substructured mass-spring oscillator system can be stabilized successfully in an experiment. The approach of DDE modelling also allows us to determine the dependence of the critical delay on the parameters of the delay compensation scheme. Using this approach we develop an over-compensation scheme that will help ensure stable experimental testing from initiation to steady state operation. This technique is particularly suited to sti structures or those with very low natural damping as regularly encountered in structural engineering.

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Bond-graph based substructuring of dynamical systems

Cited by 15 publications

References 29 publications

Emulator-based control for actuator-based hardware-in-the-loop testing

Emulator-based control for actuator-based hardware-in-the-loop testing

Robust real-time substructuring techniques for under-damped systems

Stability analysis of real‐time dynamic substructuring using delay differential equation models

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