Based on theoretical analysis and experiments, this article proposes a new model for a magnetorheological (MR) damper. The proposed model with a smooth and concise form can interpret the bi-viscous and hysteretic behaviors of the MR damper very well. The parameters in the model have definite physical meanings. The bi-viscous and hysteretic behaviors can be characterized by two parameters 0 and ...

This paper is concerned with efficient integration of bilinear H∞ control and adaptive inverse control to attain vibration isolation of structure installed with a semi-active MR damper in which its damping force is controllable by input voltage. The structure with MR damper is expressed by a bilinear dynamic equation. The role of the bilinear H∞ controller is to provide the desired damping forc...

For the past three years, students in ARCE 483 Seismic Analysis and Design in the Architectural Engineering program at Cal Poly San Luis Obispo have been designing experiments using K’nex toys. The resulting experiments have included the effects of fixity on natural frequency, flexible versus rigid performance, seismic activity on a bridge structure, soft story behavior in buildings, the effect...

In this work, a magnetorheological (MR) damper based above-knee prosthesis is design and evaluated based on its performance in swing phase and in stance phase. Initially, a dynamic system model for swing phase of a prosthetic leg incorporating a single-axis knee with ideal MR damper was built. The dynamic properties of the damper are represented with Bingham parametric model. From Bingham model...

In this paper, the efficacy of magnetorheological (MR) dampers for seismic response reduction is examined. To investigate the performance of the MR damper, a series of experiments was conducted in which the MR damper is used in conjunction with a recently developed clipped-optimal control strategy to control a three story test structure subjected to a one-dimensional ground excitation. The abil...

Semi-active suspensions have drawn particular attention due to their superior performance over the other types of suspensions. One of their advantages is that their damping coefficient can be controlled without the need for any external source of power. In this study, three control approaches are implemented on a quarter-car model using MATLAB/Simulink. The investigated control methodologies ar...

In this study, we consider the vibration mitigation problem for a structural system using a magneto-rheological (MR) damper. For this purpose, through the use of Lyapunov-based design techniques, a nonlinear adaptive controller which can compensate the parametric uncertainties related to both the structural system and the MR damper has been constructed. To overcome effects of the unmeasurable i...

The conventional hard switching half-bridge topology used as a rolling stock auxiliary power supply unit has limited switching frequency due to high power losses in semiconductors. The study analyses LLC and LCC topologies in attempt to improve the performance of the converter and presents a simulation of the operation and an estimation of power losses.

The paper is concerned with stable adaptive schemes for semi-active control of suspension systems, which can deal with uncertainties in a nonlinear model of MR damper. To compensate for unknown nonlinear hysteresis dynamics of the MR damper, an adaptive inverse controller is implemented by indirect and direct methods. In the indirect method, on-line identification of a forward model of MR dampe...