ABSTRACT
Chapter 11 is focused on the design of spacecraft control system where magnetic torque coils are used. First, the linear time-varying model is established in section 11.1. The controllability of spacecraft using only magnetic torques are proved in section 11.2 even though magnetic torque coils can provide torques in a plane instead of three-dimensional space at any time. Periodic LQR control is considered in section 11.3 where the problem is reduced to the solution of the periodic Riccati equation and an efficient solution is derived. As reaction wheel and momentum wheel have saturation problem, attitude and desaturation combined control using both reaction wheel and magnetic torques is considered in section 11.4. The proposed design simultaneously solves traditionally separated design problems at the same time. Section 11.5 proposes a different technique, the lifting method, to solve the periodic LQR problem and proves that the periodic LQR design based on lifting technique is more efficient in most cases.
