Stabilization of Undamped Gyro Platforms Using an Inertial Angular Rate Sensor

The accuracy of any gyro stabilized platform depends to a large extent upon maintaining the net torques applied to the stabilized element at a low level. This requires that the static gain of the servosystem be high in order to effectively counteract torque disturbances. Generally a basic stability problem results which requires servo lead compensation. Beyond this, the lead compensation must be effective in controlling resonant amplitudes during dynamic disturbances. This article treats the stability problem for platforms employing gyros which have negligible damping about the precession axis. The air bearing gyro is a notable example. The purpose of this paper is twofold. First, a simple analytical method is introduced to define compensation parameters which will allow control of the undamped natural frequency, and which will establish a damping factor of one half. Second, a new device is introduced which will greatly simplify the task of generating an effective compensation signal. This device is a tiny gimbal-mounted intertial angular rate sensor called "ADA."