Further Results Towards a Location-Scheduled Control Methodology

This paper presents a new strategy for the design of the attitude determination and control system (ADCS) of reconfigurable spacecraft. Assuming that the major components of a given spacecraft can be easily rearranged between missions (e.g. science payload, controller location), it is desirable to develop controller designs that are tuned for each possible configuration. Our strategy for obtaining these controller designs is referred to as location-scheduled control (LSC). The objective of this strategy is to reduce the amount of time required to develop the spacecraft ADCS during a mission life cycle by creating a family of ADCS designs a priori. Under LSC, a certain combination of sensors and actuators is paired with an appropriate control law, and then both controller gains and controller physical location are tuned for operation in multiple spacecraft configurations using a genetic algorithm. In this work the validity of the LSC approach is demonstrated through the study of a representative control problem concerning nanosatellites, a popular current example of reconfigurable spacecraft. By applying LSC, controller designs for a nanosatellite subject to actuator saturation are obtained for a large angle detumble maneuver using a nonlinear control law with previously reported stability properties.