Robust control of a variable speed control moment gyroscope

Abstract

Gyroscopes are multi-body mechanical systems which present coupled three-dimensional motion. The dynamics is nonlinear and dominated by the gyroscopic effect, which finds practical
applications in Aerospace and Naval Engineering. They can be used as attitude and angular velocity sensors, and in inertial navigation systems. They also can be used as actuators in closed loop attitude
control systems in aircraft, spacecraft and in ships, presenting several advantages over other deviceswith the same objective. In this paper, we focus in gyroscopes as actuators, known as Control Moment Gyroscopes. We initially present a new method to find the kinematics and dynamics mathematical model of the system, using the Cartan’s connection and covariant derivative. We also linearize the model in an equilibrium point, and design two parallel control laws to control the angular positions of the gyroscope’s gimbals. The inner control loop is designed in order to damp the natural nutation frequency. The external control law is a multivariable robust control law that effectively provides robustness to the system (LQG/LTR). With this control law, the system is classified as a variable rotor’s speed control moment gyroscope. Practical results are presented for an experimental setup.