A nonlinear attitude model of a satellite with thrusters, gravity torquers and a reaction wheel cluster is developed. Then the linearized version of this satellite attitude model is derived for the attitude hold mode. For comparison purpose, various control methods are considered for attitude control of a satellite. We consider a proportional derivative controller which is actually used in the ...

in this paper, a finite-time control scheme is presented for stabilization ofthe satellite chaotic attitude around its equilibrium point whenits attitude is confused by a disturbed torque. controllers and settling timeof stabilizaton are obtained, based on the lyapunov stability theoremand finite-time control scheme. this method is satisfied for any initial condition.numerical simulations are ...

The Polar BEAR satellite was launched successfully from Vandenberg Air Force Base, Calif., in November 1986. A Scout launch vehicle placed Polar BEAR into a circular, polar orbit at an altitude of lcxx) kIn. The satellite's four instruments are designed to yield data on RF communications, auroral displays, and magnetic fields in the earth's polar region. The Polar BEAR attitude control system i...

Absract Magnetic actuation utilizes the mechanic torque that is the result of interaction of the current in a coil with an external magnetic field. A main obstacle is, however, that torques can only be produced perpendicular to the magnetic field. This actuation principle has been a topic of research since earliest satellites were launched. Magnetic control has been applied for nutation damping...

A nonlinear adaptive attitude controller is designed in this paper that compensates for dynamic uncertainties in the spacecraft inertia matrix and unknown dynamic and static friction effects in the control moment gyroscope (CMG) gimbals. Attitude control torques are generated by means of a four single gimbal CMG pyramid cluster. The challenges to develop the adaptive controller are that the con...

The main purpose of this paper is to propose a nonlinear H∞ and mixed 2 / H H∞ self-fuzzy algorithm to solve large-angle robust control problem. The attitude control is one of the studied problems in recent years. Under the space environment, there often exists an unpredictable interference which results some deviations of satellite’s attitude. Therefore, it needs to develop a controller still ...

Abstract: Placing a satellite or any other spacecraft in orbit is a risky and expensive process; years of research and a lot of money are transformed into equipments that will be beyond any possibility of maintenance in case something goes wrong. Therefore, space projects must be carried on as carefully as possible in order to guarantee that satellite equipments perform its mission properly. In...

This article describes a simulator of small satellite attitude environment and dynamics, complete with a set of realistic sensors and the most commonly used actuator in this class of satellites. The simulator described is useful in attitude estimation and control algorithm development. Some results of the simulation of the PoSAT-1 satellite are presented.