A strategy of vibration control in the infra frequency band

To protect a driver in the most harmful frequency band, a control strategy for vibration isolating device with minimum stiffness is proposed focusing on motion stability in the large. In the strategy, a model of the device is structured to generate the control criteria in the operation of immenently unstable spring with "negative" stiffness. A control algorithm is considered effecting variability of the device stiffness in terms of the position and velocity data evaluation. The object protected is motionless under the vibration motion and becomes shock-free under non-vibration excitation even if there exists no external fluid damper. The validity of the approach is assessed by numerical experiment and physical measurement for an actual seat pneumatic suspension restructured with the spring and controlled by the program.