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Whole-satellite vibration isolation system with magneto-rheological (MR) damper is a new idea to solve the problem of small amplitude and medium-high frequency vibration. However, it also brings challenges to MR technology, wherein the super hysteresis and variable stiffness properties of MR damper are lack of research. Considering the particularity of MR damper under small amplitude and medium-high frequency conditions, the MR damper is identified by employing an improved Bingham model, then dynamic characteristics of the whole-satellite system are analyzed by nonlinear bifurcation theory, and then the nonlinear analysis method of MR whole-satellite system with variable parameters is proposed. To verify the effectiveness of the nonlinear analysis method of MR whole-satellite system with variable parameters, the influence of bifurcation parameters on the system parameters is analyzed qualitatively and quantitatively, then time histories and phase diagrams of fixed-parameter and parameter-varying MR whole-satellite system are compared. The analysis suggests that the improved Bingham model adequately characterizes the strong nonlinear hysteretic and variable stiffness behavior of the MR damper. Moreover, the comparison results illustrate that the time histories and phase portraits of the parameter-varying system are in good agreement with those of different fixed-parameter system, and the parameter-varying system has good adaptability in the selected range of bifurcation parameters. This study provides a basis for the design of structural parameters and the optimization of control strategy for MR whole-satellite system.

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.

Owing to the complex nonlinear hysteresis of magnetorheological (MR) damper, the modeling of an MR damper is an issue. This paper examines a novel MR damper hysteresis model based on the grey theory, which can fully mine the internal laws for the data with small samples and poor information. To validate the model, the experiment is conducted in the MTS platform, and then the experimental results are compiled to identify the model parameters. Considering the complexity of the grey model and its inverse model solution, the grey model is simplified in two ways based on the grey relational analysis method. Furthermore, the simplified grey model compares to other models to prove the superiority of the grey model. The analysis suggests the fitting results correspond to the measured results, and the mean relative error (MRE) of grey model is within 2.04%. After the grey model is simplified, its accuracy is slightly reduced, while its inverse model is easier to solve and makes a unique solution. Finally, compared with the polynomial and Bouc-Wen model, the novel model with fewer identification parameters has high accuracy and predictive ability. This novel model has fabulous potential in designing the control strategy of MR damper.

In this research effort, an innovative magneto-rheological variable stiffness and damping torsional vibration absorber (MR-VSDTVB) is proposed, and independent variable damping control and independent variable stiffness control are adopted to suppress the torsional vibration of the transmission system. MR-VSDTVB, based on semi-active control principle, exhibits a compact structure and integrates with magneto-rheological technology. First, the concept of MR-VSDTVB is discussed, and the output torque characteristic of MR-VSDTVB is analytically developed. Then, a prototype is fabricated and tested. A transmission system with MR-VSDTVB is proposed to verify the MR-VSDTVB's effectiveness. The structure and inherent characteristics of the transmission system are analyzed theoretically. Finally, an experimental setup of transmission system with MR-VSDTVB is built. Experimental results indicate that when torsional stiffness of MR-VSDTVB changes, a frequency shift phenomenon occurs; moreover, when torsional damping of MR-VSDTVB changes, the response amplitude of the experimental setup changes regularly; And finally, the on-off control test validates the effectiveness of semi-active control on the torsional vibration suppression of the transmission system. The above results verify the effectiveness of MR-VSDTVB in suppressing the torsional vibration of the transmission system. These findings are expected to expand the application of magneto-rheological technology and variable stiffness and variable damping technology in torsional vibration of transmission systems.