Multiagent Attitude Control System for Satellites Based in Momentum Wheels and Event-Driven Synchronization
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Multiagent Attitude Control System for Satellites Based in Momentum Wheels and Event-Driven Synchronization Juan L. Garcia de Arboleya · Jose Sanchez Moreno
Published online: 2 August 2014 © American Astronautical Society 2014
Abstract Attitude control is a requirement always present in spacecraft design. Several kinds of actuators exist to accomplish this control, being momentum wheels one of the most employed. Usually satellites carry redundant momentum wheels to handle any possible single failure, but the controller remains as a single centralized element, posing problems in case of failures. In this work a decentralized agent-based event-driven algorithm for attitude control is presented as a possible solution. Several agents based in momentum wheels will interact among them to accomplish the satellite control. A simulation environment has been developed to analyze the behavior of this architecture. This environment has been made available through the web page http://www.dia.uned.es. Keywords Satellite · Control · Momentum · Inertia · Wheels · Event · Asynchronous
Introduction and State of the Art Though it is possible to stabilize a satellite without an active controller using spin stabilization or gravitational gradients, most spacecrafts carry an attitude control system on board for steering the satellite. Normally it is integrated together with the orbit control into the Attitude and Orbit Control Subsystem (AOCS). While the orbit control considers the satellite as a mass point, the attitude control usually considers it as a rigid body and needs more sophisticated mathematical tools. Several actuators can be considered for controlling a satellite attitude. Specially important are thrusters, momentum wheels or magnetic torques. Among all the
J. L. Garcia de Arboleya () · J. S. Moreno Universidad Nacional de Educacion a Distancia, Madrid, Spain e-mail: [email protected]
J of Astronaut Sci (2012) 59:726–746
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possible options we have chosen the momentum wheels as the basis for this work. A set of distributed agents based on momentum wheels will be developed and simulated in the last section. Redundant Stabilization Three-axis stabilized satellites offer higher precision in pointing maneuvers and attitude control than other control solutions [1]. This higher precision can be helpful for obtaining better observations, both for distant objects and for the earth surface or to maintain better communications with the tracking stations [2]. Attitude control for satellites is a key issue because a spacecraft has to cope with different kinds of disturbances, like the solar electromagnetic radiation, gravity gradients, influx of the terrestrial magnetic field and, finally, the low altitude atmospheric drag. An attitude model for any rigid body will receive a torque of forcesτ as input, and will produce attitude and angular velocity descriptions as output. The output uses three parameters for the three degrees of freedom of the attitude (vector φ of parameters), and other three for angular speed measures
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