Dynamic Interactions Analysis Of HJ-1B Satellite Platform And Onboard Infrared Camera Scanning Mirror

This paper takes HJ-1B satellite and onboard infrared camera scanning mirror as research objects. The influences on respective motion performance caused by the dynamic interactions between them are evaluated. The emphasis is put on the influence of satellite platform's attitude motion upon infrared camera scanning mirror's continuous scanning motion. By applying hybrid coordinates method, dynamic equations of motion for a satellite system which includes central rigid body, momentum wheels, rigid rotational components and flexible solar arrays are given. Together rotational dynamic equations for flexible solar arrays and rigid rotational components are presented. The structural vibrational equations for the former are also depicted. The disturbance torques imparted by space environment are analyzed, which include gravity gradient torque, solar pressure torque, aerodynamic torque and magnetic torque. The disturbance torques imparted by many moving components are analyzed, which include single degree of freedom rotational component, two degrees of freedom rotational component, static and dynamic imbalances of momentum wheels, and flexible solar arrays. The causes and classification of the imbalances of momentum wheels are explained in detail. The formulas for time varying disturbance torques generated by them are deduced, and the corresponding researchs in literatures are fully summarized. The preceding presents the models and techniques for analysis of such interactions. A comprehensive simulation is carried out and the corresponding assessment is performed subsequently. In one aspect, the influence of various disturbances upon satellite's attitude motion is studyed by simualtion. In the other aspect, the influence of satellite platform's attitude motion upon infrared camera scanning mirror's continuous scanning motion is thoroughly analyzed. Firstly, under the assumption that the output driving torque generated by the stepper motor of the mirror is constant, such influence analysis is conducted. Secondly, a mathematic model of the stepper motor is given. Under the assumtion that the input impulse frequence is constant, the rotational motion of the stepper motor of the mirror with the mutual exertions of damping torque, friction torque and disturbance torque generated by satellite platform's attitude motion is simulated and analyzed. Both results show that the inertial coupling of the platform to infrared camera scanning mirror, to evaluate mirror motion, is negligible and so the mirror can perform scans of the Earth at the specified angular rate. But the analysis also shows that when the friction torque exerted on the stepper motor becomes large to some extend the motor of the mirror may stop rotation.