Patent ID: 6029959
Filing Date: 2000-02-29
Classification: F16F

Abstract:
A semi-active vibration isolator, comprising:a plurality of isolator devices connected between a first platform and a second platform which is to be isolated with respect to the first platform, wherein each of the isolator devices includesa passive isolator element having a first end connected to the first platform and a second end connected to the second platform, wherein the passive isolator element reduces the effect of vibratory disturbances over a limited band of frequencies,an active isolator element connected to operate in parallel with the passive isolator element, between the first and second platforms, the active isolator element having a first end connected to the first end of the passive isolator element and a second end connected to the second end of the passive isolator element, the active isolator element functioning to compensate for vibratory disturbances over a selected frequency band complementing the effect of the passive isolator element, anda sensor attached to the isolator device for sensing internal strain or stress in the isolator due to vibratory disturbances;a damping control circuit responsive to signals from the sensor, for generating signals to control the active isolator element in such a manner as to compensate for the vibratory disturbances; andan angular positioning control circuit, for generating actuator control signals to correct angular positioning errors in the second platform.