Nonlinear Controller Design for Tracking Task of a Control Moment Gyroscope Actuator

Control moment gyroscopes (CMG) are widely used as actuators for attitude control of satellites and spacecraft, which requires the controller to fulfill the tracking task of a CMG in a wide operating range, despite its highly coupled nonlinear behavior. A variety of control techniques were proposed for tracking task of the CMG unit, model 750, from Educational Control Products (ECP), but a few accomplished it in a wide operating range, e.g., the linear parameter-varying approach. Another one that may accomplish it is the nonlinear control approach. Therefore, this article proposes a nonlinear controller design based on feedback linearization for the tracking task of the CMG unit in a wide operating range. To cope with a singularity that would appear in the control signal computation, the proposed controller has a cascade structure composed of an outer tracking controller and an inner velocity controller, both based on the input-output linearization approach. The designed controller is validated via numerical simulations and real-time practical experiments.