An improved Bouc –Wen model for describing hysteretic characteristics of shock absorbers

The error between the actual damping force and the simulated damping force obtained using the Bouc–Wen model under non-identification excitation conditions is large, and the model is too sensitive to non-identification excitation amplitude and thus features poor accuracy. To solve this sensitivity problem, an improved model describing hysteretic characteristics of shock absorbers was proposed. Firstly, the mechanical properties of a magnetorheological (MR) damper were tested to obtain the damping force under various excitation amplitudes, frequencies and currents using a mechanical testing and simulation(MTS) fatigue testing machine. The smooth hysteresis loop curve was simulated based on the relationship between the slope of the hysteresis loop and the damping force. The quadratic polynomial function was used to characterize the relationship between the slope of hysteresis loop and the damping force according to the hysteresis curve characteristics. At the same time, the revision term of the exponential function for the velocity value was introduced, and the parameters of the established improved Simulink model were identified. The damping forces under different working conditions were obtained from the experiment, and the new model was simulated and validated. The damping forces obtained from new model and the experiment were compared, and the curves obtained from the model agree well with the experimental results under different working conditions. Meanwhile, the improved model was compared with the Bouc–Wen model based on the characteristic curves of the damping force. The results show that the improved model can better simulate the damping force values obtained from tests under different conditions, and is superior to the Bouc–Wen model. At the same time, the problem of poor accuracy of the Bouc–Wen model under non identification excitation conditions was improved. The new model lays the foundation for ensuring the accuracy of the vehicle suspension system response under various working conditions.