PD-type Magnetic-based Sun-pointing Attitude Control Scheme

For some low-orbit satellites, sun-pointing attitude control is an indispensable attitude mode, which is adopted to charge the solar panels in case that system turns off accidentally. Magnetic-based attitude control is adopted by more and more low-cost and highly integrated satellites due to its reliability, simplicity and portability. The magnetic Attitude Determination and Control System (ADCS) takes the magnetometer and magnetic torquer as the core, and relies on the solar sensor and gyroscope to determine or estimate the solar vector. Due to the underactuated characteristics, the magnetic-based attitude control may not be able to stabilize the whole attitude, but can only control two dimensions, which is enough to obtain the sun-pointing attitude control. In this paper, a classic PD-type full magnetic sun-pointing attitude control scheme suitable for spin or non-spin satellites is described in detail. In addition, by analyzing the control effect of actual control torque under different attitude conditions, the failure scenario of the scheme is found and the corresponding improvement scheme is proposed. Simulations show that the updated PD-type magnetic-based sun-pointing attitude control scheme have capability to meet the requirements corresponding to sun-pointing task.