Position control of seat suspension with minimum stiffness

Quality of vibration isolation of vehicle drivers in the infra-narrow band is the most essential and simultaneously is a hard-hitting goal. Use of the "negative" stiffness' phenomenon is a unique concept to minimize stiffness of a vibration isolating device and improve the quality so that protected object becomes motionless in inertial space. Though control strategy for the device with minimum stiffness sufficiently differs from the approaches based on attenuation of extraneous resonant responses. An approach for positioning such a device is proposed focusing on motion stability in large. In the approach, a model of the device is structured to generate the control criteria in operating immanently unstable mechanism of "negative" stiffness. A control algorithm effecting variability of the device stiffness in terms of the position and velocity data evaluation is considered. The object protected is motionless under the vibration and motion becomes shock-free under non-vibrational excitation even if there is no external damper. The validity of the approach is assessed by numerical experiment and physical measurement for an actual seat pneumatic suspension restructured via the mechanism and controlled by the program. (c) 2005 Elsevier Ltd. All rights reserved.