Passivity-Based Nonlinear Control Approach for Tracking Task of an Underactuated CMG

This article proposes a passivity-based nonlinear control approach to deal with the tracking task of a control moment gyroscope (CMG), which is an underactuated nonlinear MIMO system with coupled dynamics, where the main goal is the tracking of the unactuated states in a wide range of operation. To overcome this underactuation, the proposed nonlinear controller employs the CMG intrinsic reaction torques. The closed-loop system stability is analyzed by invoking the Lyapunov stability and Matrosov's theorem. Numerical simulations and real-time practical experiments with the real plant are performed to validate the proposed nonlinear controller, as well as its performance is analyzed by contrasting the experiment results with the ones obtained by authors’ previous established nonlinear controllers.