This paper proposes a hybrid suspension system, consisting of a linear electric motor (LM) and a semi-active mono-tubed magnetorheological damper (MRFD), to improve vehicle dynamics with lower power demand. For determining the damping force directly and concisely, a modified bi-viscosity magnetorheological fluid (MRF) model that explicitly includes the current parameter is developed. The fabricated LM and MRFD are calibrated and tested for validation of the implemented mathematical models. The simulation results show that the modified bi-viscosity model is able to calculate the experimental MRFD external forces very well. Thereafter, the hybrid suspension system is integrated into a 2-DOF (degree-of-freedom) quarter-vehicle dynamic model for simulation analysis, considering bump and pothole road profiles and the wheel bounce movements. Moreover, the two step-control methods, namely SC1 and SC2, are modelled for enhancing vibration mitigation and reducing power demand. The MRFD current influences on the root mean square (RMS) of the vehicle body vibration amplitudes are studied. Results reveal that the optimal MRFD current is ranged from 1 to 2.2A considering the SC1 method. Finally, the energy efficiency of the step-control methods is proved to be much higher than the PID method especially at low vehicle speed and in large road heave situations.

本文提出了一种混合悬架系统，由线性电动机 (LM) 和半主动单管磁流变阻尼器 (MRFD) 组成，以在较低功率需求的情况下改善车辆动力学。为了直接和简明地确定阻尼力，开发了一种明确包含当前参数的改进的双粘度磁流变流体 (MRF) 模型。对制造的 LM 和 MRFD 进行校准和测试，以验证所实现的数学模型。仿真结果表明，修正后的双粘度模型能够很好地计算实验MRFD外力。此后，将混合悬架系统集成到 2-DOF（自由度）四分之一车辆动力学模型中，以进行仿真分析，同时考虑颠簸和坑洼路面轮廓以及车轮反弹运动。而且，对两种步进控制方法（即 SC1 和 SC2）进行了建模，以增强减振和降低功率需求。研究了MRFD电流对车身振动幅度均方根（RMS）的影响。结果表明，考虑到 SC1 方法，最佳 MRFD 电流范围为 1 到 2.2A。最后，证明了步进控制方法的能量效率远高于PID方法，特别是在低车速和大路面起伏情况下。