Stability analysis on the system for the fast start-up of a liquid driven gyro

Liquid driven gyro is the key sensor in the attitude control system for long-range unsophisticated-controlled rockets. A new electromagnetic control scheme was presented. It is the principle of the scheme that the electromagnetic control moment makes the inertial axis of gyro close to and follow the axis of missile body quickly before launching; the off axis angle between the gyro axis and missile axis is picked up by the signal detection coil of the liquid driven gyro; after appropriate processing, the signal is fed into the electromagnetic control coil, thus an electromagnetic control moment is produced that forces the gyro axis to precess in the direction of reducing the off axis angle and further ensuring the gyro for sensing the direction of missile axis exactly after launch. A theoretical dynamic model of the control system was deduced. The stability of the control system was analyzed using Lyapunov direct method and the condition of stability was deduced. Simulations of the effect of missile axis swing on the inertial axis of gyro were carried out. The simulation result verifies the effectiveness of the proposed scheme.