Abstract: When a dynamically tuned gyroscope (DTG) starts or stops on a moving base, its rebalance loop should keep the tilt angle small enough to protect the flexure joint. Presented in this article is a design method for a DTG rebalance loop on a moving base using robust H_∞ control. The mathematical model of the DTG described in the state space is first established, taking the applied angular rate as external disturbance input, and the parameter changes along with the rotor spin rate during the start or stop phase as system parameter perturbation. Next, a robust H_∞ control, which is able to cope with disturbance attenuation in the case of parameter perturbation, is adopted to realize the DTG rebalance loop on a moving base. Then, the robust H_∞problem is transformed to a standard H_∞ problem and the linear matrix inequality (LMI) method is used to design the desired controller. Simulation results show that the designed rebalance loop can keep the tilt angle within arc-minute during start or stop on a moving base without the need for rotor spin rate information.

Key words: dynamically tuned gyroscope, rebalance loop, moving base, robust H_∞control, linear matrix inequalities