Experimental study of a novel quasi-active negative stiffness damper system for achieving optimal active control performance

Abstract

Compared to the semi-active control and passive control systems, an active control system is able to achieve the most desirable vibration control performance because of its high adaptability and capacity to directly produce the required optimal control force (ROCF). However, the disadvantages of high energy consumption and low reliability limit its wide application. To address this dilemma, a novel ‘Quasi-active’ control concept and a representative quasi-active negative stiffness damper (QANSD) system integrating a negative stiffness element and an MR damper were proposed by the authors very recently. The QANSD system has been theoretically and numerically verified to be able to fully generate the ROCF and realize active control performance with much less external power consumption than a semi-active control system. To further validate the effectiveness of the innovative concept and the proposed QANSD system, in this study, a comprehensive experimental investigation was conducted based on the developed prototype device. The fundamentals of the QANSD system including realizations and mechanical behaviours are firstly introduced, and the experimental prototype and setup are then provided. Following that, experimental tests on the QANSD system and its MR damper and negative stiffness element components were carried out under different harmonic excitations and command currents. Based on the experimental test results, artificial neural network-based forward and inverse models are designed for the QANSD force and command current identifications. Moreover, the real-time vibration control performances of the QANSD system are investigated and compared with the active and semi-active control systems. The experimental results revealed that compared to the MR damper that was only able to generate force in the opposite direction of structural motion, the developed QANSD system had the capacity to provide both velocity-resisting and velocity-assisting forces as the ROCF does. Its vibration control performance could fully match that of the desired active control system, but with much lower energy consumption.