Gyro Feedforward Control of an IMU-Based Inertial Stabilization Gimbal

Disturbance attenuation of the inertial stabilized platform (ISP) is usually limited in a low control bandwidth due to structural resonances resulting unmodel dynamics. This paper proposes a combination of inertial-rate feedforward and feedback to implement high-performance disturbances isolation in the ISP, which breaks the limitation on feedback loop bandwidth. A novel feedforward controller could be permitted into inertial feedback system to obtain high-bandwidth isolation. An encoder-based inner-rate loop is used to alleviate the friction, providing an approximately linear control plant for a gyro-based outer-rate-loop. As a result, the gyro feedforward controller can be directly plugged into the dual-rate control loop, which avoids the inertial-sensor signal couplings in the line of sight(LOS) coordinate frame. Therefore, a gyro-based control scheme coupled with a gyro feedforward control is proposed to further achieve disturbance isolation in the inertial measurement unit(IMU)-based ISPs. Theoretical analysis and experimental results illustrate the proposed approach can effectively isolate disturbances.