Alireza Aghalari; Javad Tayebi
Volume 9, Issue 1 , May 2016, , Pages 13-23
Abstract
Recently, many researchers are examining the possibility of the small satellites or micro satellites, because small satellites are easier and faster to develop and thereby, provide increased launch opportunities. In this paper designing and experimental testing of three axis agility satellite simulator ...
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Recently, many researchers are examining the possibility of the small satellites or micro satellites, because small satellites are easier and faster to develop and thereby, provide increased launch opportunities. In this paper designing and experimental testing of three axis agility satellite simulator - equipped with pyramid configuration of SGCMG- with implementation of PID and feedback quaternion strategies are presented. These control strategies in the two different control gains and two different type of maneuvering about single and three axis are presented. First actuators and simulator of satellite have introduced and control strategies are simulated in Matlab/Simulink software. Then control strategies have implemented in the simulator’s computer and attitude control testing is executed. Finally the experimental data are compared with simulation results. In order to avoiding of singularity condition, SR method is used in steering law of single control moment gyros system. Results shown that agility maneuver of simulator realized and numerical results are almost according to experimental tests.
A.A Nikkhah; J. Tayebi; J. Roshanian
Volume 7, Issue 2 , July 2014, , Pages 1-9
Abstract
In this paper attitude control system of nanosatellite based on Single Gimbal Control Moment Gyroscope (SGCMG) is presented. A LQR/LQG method is developed for stability of satellite and a feedback quaternion strategy is used for maneuvering mode. In the stabilization mode LQR/LQG controllers ...
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In this paper attitude control system of nanosatellite based on Single Gimbal Control Moment Gyroscope (SGCMG) is presented. A LQR/LQG method is developed for stability of satellite and a feedback quaternion strategy is used for maneuvering mode. In the stabilization mode LQR/LQG controllers are designed with linearization of nonlinear dynamic equation of satellite and control moment gyroscope, so that in other reseach didn’t use this controller in the stabilization mode of this system. In the maneuvering mode a feedback quaternion controller applyed for nonlinear system. Numerical simulations are provided to show the efficiency of the proposed controller for a nanosatellite with four single gimbal control moment gyroscope pyramid cluster. Results of simulations shown that LQR/LQG method is more accurate in compared with feedback quaternion controller.
Alireza Aghalari; Javad Tayebi; Ahmad Kalhor
Volume 5, Issue 4 , January 2013, , Pages 61-68
Abstract
Recently, many space missions have been using small satellites, because small satellites are easier and faster to develop and thereby, provide increased launch opportunities. Some of these missions include tasks that required agile maneuvers. In this paper, attitude stability testing of an agile three-degree-freedom ...
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Recently, many space missions have been using small satellites, because small satellites are easier and faster to develop and thereby, provide increased launch opportunities. Some of these missions include tasks that required agile maneuvers. In this paper, attitude stability testing of an agile three-degree-freedom micro-satellite simulator – which is equipped with a pyramid arrangement of single-gimbal control-moment gyros (SGCMGs) – is presented. In the attitude stability testing, the local quadratic regulator (LQR) control strategy is used, which has superiority to other approaches due to its independence of using steering law. This simulator allow to test different control laws by using SGCMGs. In this work, after introducing the actuator and satellite simulator and using the control strategy in the simulator, the attitude stability testing is performed and then, the experimental results are presented and discussed. The results show the attitude stability of the simulator which is exposed to the disturbing toques.
