TECHNOLOGY PREDEVELOPMENT FOR ACTIVE CONTROL OF VIBRATION VERY HIGH ACCURACY POINTING SYSTEMS

摘要

This paper presents the development of key technologies for the control of micro-vibrations onboard high pointing accuracy satellites. They include the development and/or the pre-qualification of four flight prototypes: 1. The Multi-purpose Active Isolation System (MAIS) is a 6 DOF isolator based on six active struts implemented in an hexapod configuration. It is controlled by an hybrid analogueumerical electronics based on an MCM 21020 DSP board. The MAIS concept covers a large range of applications: isolation of optical payload, reaction wheels, etc. The reference application for the MAIS pre-development is the isolation of a laser diode implemented at the entrance of a telescope to generate a pseudo-star with a pointing stability of 100 nano-radians. 2. The Adaptive Centralised Control System (ACCS) aims at cancelling the disturbances generated by noisy equipment such as reaction wheels at the location of sensitive payloads. The centralised electronics controls acquire the signal of distributed sensors to drive a set of actuators. The objective is to reduce by 30 to 40 dB the effect of harmonic disturbances on the payload by applying destructive vibrations. The ACCS fast signal processing tasks and slow control algorithms are implemented on a MCM 21020 DSP board. 3. An hybrid numeric/analogue electronics board based on a MCM 21020 DSP is developed to acquire the signal of 6 piezo sensors and to drive up to 6 piezo actuators. This board will be used to implement the ACCS function and to drive the MAIS in closed loop at 10 kHz. 4. The Integrated Active Damping Device (IADD) is as a stand-alone device integrating all functions necessary for active damping: piezo sensor & actuator, acquisition, drive & processing electronics. The objective is to define a versatile product applicable to a wide range of space structures at a minimum cost, mass, volume and power consumption. The performance objective is to reduce vibrations by 20 dB at a given frequency.