A hysteresis model based on “shape function + memory mechanism” is presented and its feasibility is verified through modeling the hysteresis behavior of a magnetorheological (MR) damper. A hysteresis phenomenon in resistor-capacitor (RC) circuit is first presented and analyzed. In the hysteresis model, the “memory mechanism” originating from the charging and discharging processes of the RC circuit is constructed by adopting a virtual displacement variable and updating laws for the reference points. The “shape function” is achieved and generalized from analytical solutions of the simple semi-linear Duhem model. Using the approach, the memory mechanism reveals the essence of specific Duhem model and the general shape function provides a direct and clear means to fit the hysteresis loop. In the frame of the structure of a “Restructured phenomenological model”, the original hysteresis operator, i.e., the Bouc-Wen operator, is replaced with the new hysteresis operator. The comparative work with the Bouc-Wen operator based model demonstrates superior performances of high computational efficiency and comparable accuracy of the new hysteresis operator-based model.
Semi-active suspensions based on magnetorheological (MR) dampers are expected to innovate automotive suspension systems. However, the accuracy of the damping force models of MR dampers affects the control performance of MR semiactive suspension systems. Based on the experimental data of a self-developed MR damper, the parameters of a resistorcapacitor (RC) hysteresis model are identified. The obtained RC hysteresis model can describe and predict the hysteresis nonlinear damping force of the MR damper effectively. Further, the dynamic model of a 1/4 MR semi-active suspension system based on the MR damper is established, and a linear quadratic regulator (LQR) control strategy based on state feedback is designed. The performance of the 1/4 MR semi-active suspension system is simulated and analyzed in time and frequency domains.
Magnetorheological dampers (MRDs), a semi-active actuator based on MR effect, have great potential in vibration/shock control systems. However, it is difficult to establish its inverse model due to its intrinsic strong nonlinear hysteresis behaviors, and sequentially the precise, fast and effective control could not be realized effectively. This paper presents an inverse model for MRDs based on a restructured phenomenological model with incorporation of the "normalization" concept. The proposed inverse model of MRDs is validated by the simulation of the force tracking. The research results indicate that the inverse model could be applied for the damping force control with consideration of the strong nonlinear hysteresis behaviors of the MRDs.
In this paper, for modeling the MR dampers, based on the phenomenological model, a normalized phenomenological model is derived through incorporating a “normalization” concept and a restructured model is proposed and realized also with incorporation of the “normalization” concept. In order to demonstrate, a multi-islands genetic algorithm (GA) is employed to identify the parameters of the restructured model, the normalized phenomenological model as well as the phenomenological model. The research results indicate that, as compared with the phenomenological model and the normalized phenomenological model, (1) the restructured model not only can effectively decrease the number of the model parameters and reduce the complexity of the model, but also can describe the nonlinear hysteretic behavior of MR dampers more accurately, and (2) the normalized phenomenological model can improve the model efficiency as compared with the phenomenological model, although not as good as the restructured model.