Magnetorquers only Attitude Maintaining Using Dynamic Attitude Simulator Environment

Abstract

Magnetic controllers for maintaining and varying spacecraft's directivity using only magnetorquers are presented using dynamic attitude simulator environment (DASE), which includes a flight computer and the complete satellite communications architecture. Magnetorquers are environmental actuators that on the contrary to reaction wheels do not have any moving parts. For that reason using only magnetorquers for the tasks where precise attitude control is not required prolongs mission lifetime. Despite the inability to produce torque along the Earth's magnetic field vector magnetorquers can still provide the sufficient pointing accuracy for the on-board antennae with help of B-max and VBC controllers. The controllers are designed for RASAT, an Earth observation satellite, to be launched to a sun-synchronous low Earth orbit (LEO) orbit. The satellite ground communication is achieved via rigidly mounted X-band and S-band antennae with restricted radiation patterns. The controllers' purpose is to maximize the high speed communication duration by directing the satellite's side where the antennae are located towards the ground station during each pass. The results show that magnetic actuation provides sufficient pointing accuracy that surpasses the Nadir-pointing flight mode in terms of communication duration. Nomenclature e = error received by a controller SET v = set-point vector B = Earth' magnetic field vector as measured in satellite's body frame m = magnetic dipole moment vector expressed in satellite's body frame  τ = torque vector Z = satellite's +Z vector expressed in orbit frame P K = proportional gain of a controller D K = differential gain of a controller b o R = rotation matrix from orbit frame to body frame / b bi ω  = angular velocity vector of satellite body frame with respect to inertial frame, represented in satellite body frame. I = Inertia matrix of the satellite D T  = total disturbance torques MT T  = torques generated by the magnetorquers 1 Researcher, Electrical and Electronics Engineer, M.Sc.

Recent advances in the active magnetic control of satellites

“…В линейном приближении можно использовать углы ориентации и их производные. В [84] предложено управление: где e mag -направление в связанных осях, которое следует совместить с вектором геомагнитной индукции.…”

Rasat ADCS flight software testing with Dynamic Attitude Simulator Environment

“…The data is generated according to the actual device specifications ( Table 1). The flight computer perceives the data as if it is being received from the real sensors and actuators [7]. …”