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ATTITUDE CONTROL INVESTIGATION USING SPACECRAFT HARDWARE-INTHE-LOOP SIMULATOR

The Distributed Spacecraft Attitude Control System Simulator (DSACSS) testbed at Virginia Polytechnic Institute and State University facilitates investigation of various control strategies for single and multiple spacecraft. DSACSS is comprised of two independent hardware-in-the-loop simulators and one software spacecraft simulator. The two hardware-in-theloop spacecraft simulators have similar subsystems as flight-ready spacecraft, mounted on independent spherical air-bearing platforms. The nonlinear attitude control investigation uses one hardware-in-theloop simulator with three reaction wheels as the actuator for attitude control. A Lyapunov based angular rate controller and Modified Rodrigues Parmater (MRP) attitude controller are evaluated using the hardware simulator. The angular rate controller resulted in successfully driving the angular rates of the simulator to zero. The MRP attitude controller resulted in successfully driving the angular rates and MRP attitude vector of the simulator to zero. The angular rate and MRP controllers demonstrate the capability of investigating nonlinear attitude control strategies in real-time with hardware similar to flightready spacecraft.