Performance of a Smart Vibration Isolator for Precision Spacecraft Instruments

Abstract

This paper describes the configuration and measured performance of an hybrid, active-passive vibration isolation mount designed to mitigate vibratory disturbances on sensitive spacecraft instruments. The device, called the Active Vibration Canceler (AVC), consists of a passive isolation stage using composite leaf springs faced with shape-memory metal sheet material to provide load-adaptive damping, and an active, force-canceling stage using a motion-amplified electrostrictive stack actuator to augment attenuation of transmitted vibrations in the 10-120 Hz band. The paper discusses the features of the AVC design and active control architecture, and presents results of experiments characterizing the broadband performance of the device. Performance measurements show that the AVC provides up to 40 dB attenuation of base disturbances at 100 Hz, and that the electrostrictive active stage provides in excess of 10 dB attenuation over the passive isolator in the range 10-100 Hz. The measurements indicate that hybrid devices of this type can be effective in reducing transmitted vibrations to sensitive instruments, and that the incorporation of active elements can significantly enhance attenuation of broadband vibrations in isolation applications.

Hybrid H2control Design for Vibration Isolation

“…However, equation (16) shows that this amount is effectively reduced when the feedforward sensor is used. Of course, the effective reduction is a function of the relative``quality'' of the feedforward measurement, given by V ms .…”

“…This analysis can also be applied to the typical engineering problem of actively isolating a payload from the vibrations of a moving platform (see reference [16], for example). In this case active controller design ®ts into the hybrid control architecture when both the platform and the isolation mass are equipped with displacement sensors that have signi®cant dynamics.…”

Broad-band Viscoelastic Rotational Vibration Control for Remote Sensing Applications

“…In this manner, Regelbrugge et al (1996) have shown that efficient vibration amplitude reduction is accomplished without the cost of an active system. Furthermore, Webster and Semke (2004) have demonstrated that enhanced performance is attained with the use of frequency-dependent viscoelastic structural components.…”

A dynamics model for nonlinear electrostrictive actuators

“…For example, PMN-PT multilayered actuators were recently used in an active mirror positioning mechanism, which was part of the optical scheme for correcting the Hubble Space Telescope's spherical aberration [8]. Researchers also have examined PMN-PT for active vibration isolation of spacecraft systems [9] and underwater sonar applications [10], [11].…”