Semi-active control of magneto-rheological variable stiffness and damping seat suspension with human-body model

In this study, adding a headrest to the conventional vehicle driver seat is investigated to improve the driver comfort and decrease the driver damages. For this purpose, a conventional biomechanical human body model of wholebody vibrations is provided and modified by adding a head degree of freedom to the body model and a headrest to the seat model. The basic model is in the sitting posture, lumped parameters and has nine DOFs for the human body, on contrary to the proposed model which has ten DOFs. The new human body DOF is the twisting motion of the head and neck. This new DOF is generated because of headrest adding to the driver’s seat. To determine the head discomforts, the Seat to Head (STH) indexes are studied in two directions: horizontal and vertical. The Genetic Algorithm (GA) is used to optimize the STH in different directions. The optimization variables are stiffness and damping parameters of the driver’s seat which are 12 for the basic model and are 16 for a new seat. The integer programming is used for time reduction. The results show that new seat (equipped by headrest) has very better STH in both directions.

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Semi-active vibration control of a transmission system using a magneto-rheological variable stiffness and damping torsional vibration absorber

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/0954407021999493 ◽

2021 ◽

pp. 095440702199949

Author(s):

Wenfeng Li ◽

Xiaomin Dong ◽

Jun Xi ◽

Xiong Deng ◽

Kaiyuan Shi ◽

...

Keyword(s):

Active Control ◽

Torsional Vibration ◽

Variable Stiffness ◽

Transmission System ◽

Vibration Absorber ◽

Experimental Setup ◽

Variable Damping ◽

Independent Variable ◽

Magneto Rheological ◽

Stiffness And Damping

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.

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