Experimental evaluation of an adaptive inverse compensation technique for real-time simulation of a large-scale magneto-rheological fluid damper

Abstract

Magneto-rheological (MR) dampers are semi-active control devices whose characteristics are varied under different current inputs in accordance with semi-active control laws to achieve optimized vibration control of a structural system. Experimental evaluation of the effectiveness of MR dampers for seismic hazard mitigation using selected control laws is necessary to enable performance-based design procedures to be developed and for these devices to become accepted by the practical design community. Real-time hybrid simulation provides an economical and efficient experimental technique which enables both the damper rate dependence and the damper–structure interaction to be accounted for. A successful real-time hybrid simulation requires accurate actuator control to achieve reliable experimental results. A time delay and actuator time lag (referred to hereafter as simply the delay) can be introduced into the actuator response due to state determination, communication, and servo-hydraulic dynamics. The variable current inputs and resulting variable forces induced by semi-active control laws pose additional challenges for actuator control by introducing variable delay in a real-time hybrid simulation. In this paper a newly developed adaptive inverse compensation technique is experimentally evaluated for application in real-time hybrid simulation involving an MR damper subjected to band-limited white noise-generated random displacements and variable current inputs. Actuator control is assessed using different evaluation criteria. The adaptive inverse compensation method is demonstrated to achieve good actuator control and therefore shows good potential for use in real-time hybrid simulation of structural systems with semi-active MR dampers.