A comparative study and unification of two methods for controlling dynamically substructured systems

Abstract

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. SUMMARY This paper addresses the problem of advanced testing of systems via the principle of dynamic substructuring. Use is made of the hybrid simulation (HS) scheme framework to develop a new method of synthesis for the dynamically substructured system (DSS) scheme of Stoten and Hyde; [1]. Principal reasons for doing this are (i) to improve upon the original method of DSS synthesis by adopting the more intuitive framework of HS and (ii) to enable the amalgamation of HS and DSS into a unified substructured system (USS) scheme, so that the significant advantages of DSS can be incorporated into an existing HS scheme as a straightforward retrofit. Having established the common framework for HS/DSS the paper also illustrates, by way of an example, compensator/controller synthesis for the two schemes, together with their advantages and disadvantages. In doing this both schemes are retained in their basic forms, i.e. there are no additional control embellishments used in this work, such as delay compensation, adaptive control or other advanced control methods. In order to maintain as much transparency as possible, use is made of well-known classical control techniques. Common problems associated with the substructure testing technique are also investigated, including the effects of physical parameter uncertainty, pure delays in signals and a 'split-mass' in the substructure formulation. It is shown that, although the new formulation of controlled-DSS requires more design effort than compensated-HS, the advantages of DSS in terms of stability and robustness significantly outweigh this small disadvantage at the design stage.

Enhancements of Nonlinear Substructuring Control for Shake Table Experiments on Severely Damaged Structures

“…Unlike HS, DSS regards the set of two substructures and actuation systems as the controlled system, and its controllers are designed to minimise the error between the two signals of the substructures. Because of this feature, the stability and control performance of DSS are more robust against pure time delay than those of HS [42,50]. Tus, DSS does not require delay compensation, which is fundamental to HS.…”

New methods for dynamically substructured system testing of a railway car pantograph

“…DSS has been shown to overcome these problems due to the actuator dynamics via appropriate automatic control system design, resulting in robustly stable assignment of the closed-loop system roots. 15 Therefore, automatic control techniques are utilised to synthesise both the motion of the numerical OCS and that of the physical actuator/pantograph head. The DSS testing method has already been validated in the ACTLab, University of Bristol, via a simple mechanical rig exhibiting representative motion of a pantograph.…”