Gain scheduled inverse optimal control for fine pointing of a spacecraft camera

The problem of controlling a system modeled as two coupled bodies, a spacecraft and a camera, is considered here. These two bodies are connected by active truss members forming a system of springs and piezoelectric actuators to damp out vibrations. There is also a satellite mounted reaction wheel cluster to perform slew maneuvers. An inverse optimal controller is designed to control the attitude of the satellite and improve the pointing performance of its large earth observation camera. It is based on gain scheduled minimum-norm optimization. A gain scheduling strategy is used in this paper to achieve an optimal tradeoff between settling time and integrated torque, under torque saturation constraints. Simulation results show that the proposed controller compares favorably with a conventional quaternion error feedback controller, which is used as a benchmark.