The effect of physical parameters of inertial stabilization platform on disturbance rejection ability and its improvement method

Abstract

The development of space optical communication requires arcsecond precision or even higher precision of the tracking performance of ATP(Acquisition, Tracking and Pointing) system under the condition of base disturbance. ATP system supported by stabilized reference beam which is provided by inertial stabilization platform with high precision and high bandwidth, can effectively restrain the influence of base angular disturbance on the line of sight. To get better disturbance rejection ability, this paper analyzes the influence of transfer characteristics and physical parameters of stabilization platform on disturbance stabilization performance, the result shows that the stabilization characteristics of inertial stabilization platform equals to the product of rejection characteristics of control loop and disturbance transfer characteristics of the platform, and improving isolation characteristics of the platform or extending control bandwidth can both achieve the result of getting a better rejection ability. Limited by factors such as mechanical characteristics of stabilization platform, bandwidth/noise of the sensor, and so on, as the control bandwidth of the LOS stabilization platform is limited, and high frequency disturbance can not be effectively rejected, so the rejection of high frequency disturbance mainly depends on the isolation characteristics of the platform itself. This paper puts forward three methods of improving the isolation characteristics of the platform itself, which includes 1) changing mechanical structure, such as reducing elastic coefficient, increasing moment of inertia of the platform, and so on; 2) changing electrical structure of the platform, such as increasing resistance, adding current loop, and so on; 3)adding a passive vibration isolator between the inertial stabilization platform and the base. The result of the experiment shows that adding current loop or adding a passive vibration isolator can effectively reject high frequency disturbance.