Lyapunov-Based Nonlinear Control Applied to a Control Moment Gyroscope

One of the main applications of a mechanical control moment gyroscope (CMG) as actuator is the attitude control of spacecraft and satellites, which requires a wide operating range. Motivated by this, this paper investigates the feasibility of a Lyapunov-based nonlinear control applied to the tracking task of a CMG unit from Educational Control Products, model 750, in its SISO configuration. This problem involves an underactuated system, in which the output signal is the unactuated state, posing additional challenges to control design. To deal with it, an additional internal control signal is employed and the stability analysis of the closed-loop system is given by invoking both Lyapunov stability and Matrosov’s theorem. To validate the proposed controller, numerical simulations and practical experiments were performed and contrasted with the authors’ previous designed nonlinear controllers.