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Due to the high frequency hardening effect in applications of satellite and precision vibration isolation, it is an urgent need to analyze and improve the magnetorheological (MR) performance of MR damper under small-stroke and medium-high frequency excitations. In this paper, a compact MR damper with pressure controlled mechanism is proposed, analyzed and tested. Considering the inertial, pre-compression and compressibility of MR fluid, the dynamic physic model is established to analyse the output characteristics with pre-compressions under small-stroke and medium-high frequency excitations. And then, the critical model between the pre-yield region and post-yield region is obtained. The critical boundary between different excitations is derived and comparatively analyzed. Finally, the experiments with the proposed MR damper are carried out. Compared with theoretical results, the damping force and dynamic stiffness increase with the increase of the applied current and excitations. Besides these, the energy dissipated performance can be improved by the pre-compression. When the initial pressure increases to 5 MPa with the fixed frequency of 10 Hz, the energy dissipation is increased by 43.5%. So the pre-compression is an effective way to solve the high frequency hardening. Besides these, the derived critical model can predict the performance of MR damper at different excitations.

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The satellite carried by the launch vehicle is subject to complex loads in the launch process, which can easily lead to the failure of the satellite launching. To improve the response of an existing magnetorheological (MR) whole-satellite system under small amplitude and medium-high frequency vibration during the launch phase, the MR damper is redesigned, and the controllability of the improved system is analyzed, and then a human-simulated intelligent controller (HSIC) is designed. After analyzing the over-damping problem of the existing MR whole-satellite system through sinusoidal sweep and impact simulation tests, the MR damper is redesigned and tested, then the controllability of the improved system is analyzed using vibration theory. Based on the theory of the HSIC, the feature model, control rules, and control modes of the intelligent controller are designed, and the controller parameters are optimized by genetic algorithm. The system simulation model based on HSIC is built to simulate the vibration control of the system. The simulation results show that compared with the skyhook control, the HSIC control method can not only effectively reduce the satellite resonance peak, but also has an obvious vibration reduction at a specific frequency band (40 Hz), which verifies the effectiveness of the algorithm.

In order to reduce the cost of sensors in automotive magnetorheological suspension systems and improve system reliability, a structural design scheme of automotive magnetorheological dampers with asymmetric mechanical characteristics is proposed. In this structure, the rebound damping coefficient with or without the action of the magnetic field will be greater than the compression damping coefficient, which solves the influence of the traditional magnetorheological damper limited by its own adjustable range, and continuously outputs the passive damper under different working conditions. According to the structural design plan, the mechanical output characteristics of the system are analysed theoretically, and the prototype machine is processed and tested. The research results show that the designed magnetorheological damper has the working characteristics of continuously outputting asymmetric damping force, which verifies the effectiveness of the design ideas and methods.