MIMO-FEA Active Vibration Suppression of a Satellite Using an Adaptive Composite Thruster Platform

Adaptive or intelligent structures which have the capability for sensing and responding to their environment promise a novel approach to satisfying the stringent performance requirements of future space missions. This research focuses on a finite element analysis (FEA) multi-input-multi-output (MIMO) approach for vibration suppression and precision position control of a satellite thruster and its structure, due to the thruster-firing, employing an intelligent composite thruster platform. This smart platform connects the thruster to the structure of the satellite and has three active struts and one active central support with piezoelectric stacks as actuators, and each has a sensor at its base. It also has an active circular composite plate as the top device plate with nine embedded piezoelectric patches that six of them are back-to-back and function as three actuators pairs and three of them are placed next to the bottom actuators and function as sensors. Here, the predominant modes of the structure are first determined. In the FEA method, a finite element harmonic analysis was employed to develop a vibration suppression scheme, which was then used to study the vibration control of the satellite structure using the vibration suppression capabilities of the intelligent platform mounted on the satellite. In this approach, the responses of the structure to a unit external force as well as unit internal piezoelectric control voltages are first determined, individually. The responses are then assembled in a system of equation as a coupled system and then solved simultaneously to determine the control voltages and their respective phases for the system actuators for a given external disturbance. Next, this technique was applied to the vibration suppression of the satellite frame as well as its thruster simultaneously as a coupled problem and the results are discussed. This approach is an effective technique for the design of smart structures with complex geometry to study their active vibration suppression capabilities and effectiveness. The entire system has ten actuators: four piezoelectric stack actuators and three pairs of piezoelectric patch actuators.