Hybrid Control Strategies for Rapid, Large Angle Satellite Slew Maneuvers

This research investigated hybrid control strategies for rapid satellite pointing. First, a detailed computer simulation model of AFIT's SIMSAT satellite simulator was constructed. Control strategies were developed to enable the system to perform large-angle, 3-axis slewing maneuvers using a combination of both thrusters and reaction wheels. To handle the non-linear model, a State Dependent Riccati Equation controller was programmed and successfully controlled the computer-modeled satellite for any given slewing maneuver. A simpler PD controller was then programmed and demonstrated on the computer simulation of SIMSAT, using a combination of thruster and reaction wheel control inputs for large-angle single axis maneuvers and for small angles using three-axis control. There was good agreement between the experimentally obtained maneuver results and those produced with the computer simulation model for the single-axis case. Lastly, the trade-off between settling time and thruster fuel is discussed, as well as the variation of gains required to achieve maximum performance for a desired slew.