HYSTERESIS BEHAVIOR COMPUTATION AND DYNAMIC DESIGN OF MAGNETORHEOLOGICAL DAMPERS UNDER SINUSOIDAL DISPLACEMENT EXCITATION

摘要

Damping force-velocity hysteresis of a magnetorheological (MR) clamper under sinusoidal displacement excitation is not only a typical indication of its dynamic performance,but also the foundation upon which a practical control strategy is established. Although numerous parametric and nonparametric models are effectively in predicting the hysteresis,their accuracy strongly depends on specific experimental data. Furthermore,little design guiding information can be explored from these models. With compressibility of MR fluid considered,ordinary differential equations (ODEs) of a physical MR damper model is derived in this paper,and comparison between model results and experimental data of a literature shows good agreements. Then a corresponding lumped parameter model is developed,that is,a quasi-static MR model connected in series with a spring expressing compression of MR fluid. Moreover,the spring stiff expression is found to be equivalent to the "oil spring" in hydraulic technology. Decomposing a quasistatic MR model further to a friction element and a parallel-connected viscous element,these two basic elements in combination with a spring together fundamentally constitute a dynamic MR damper model. Consequently,for the first time (to authors' knowledge),a clear developing process of the hysteresis is presented with these three basic elements. As another main contribution of this paper,expression for calculating hysteresis width is derived by neglecting viscous element,and dynamic design method of MR dampers is proposed. Results show that a MR damper should be designed as short stroke and large effective area for the purpose of reducing the hysteresis.