NONLINEAR DYNAMICS OF THE SMALL-MASS GYROMOMENT AOCS WITH PLASMA THRUSTERS FOR COMMUNICATION SATELLITES

摘要

The paper contains the some results on designing AOCS for small geostationary communication satellites. The approach applied is based on two main assumptions: 1. Thruster unit (TU) based on plasma jet thrusters (RT) is used to perform two tasks: (ⅰ) satellite attitude control and unloading of an accumulated angular moment (AM), and (ⅱ) satellite orbit control; 2. a small-mass moment gyrocomplex (MGC) based on the reaction wheels (RW) or on the single-gimbal control moment gyroscopes -gyrodines (gyro) having a small AM is used; in this case a volume of the MGC's AM variation envelope may be essentially less than the module of the satellite AM vector obtained at the moment the satellite is separated from a launcher. At a separation moment, a satellite body AM vector has an arbitrary direction, therefore the main problem is to coincide this satellite vector with the maximum inertia satellite body axis (the resulting rotation of the satellite is relative to this axis) using only the MGC having small resources for the AM and control torque variation domains. Moreover, essentially nonlinear dynamical processes are arising from a moving the total AM vector of mechanical system with respect to the satellite body reference frame (BRF). The solution achieved is based on the methods for synthesis of nonlinear control laws and on rigorous analytical proof for the required satellite rotation stability. These results were verified by the careful computer simulation of nonlinear processes in a close-loop.