Hamed Arefkhani; Mehran Mehdi-Abadi; Seyed Mohammad Mehdi Dehghan
Volume 9, Issue 2 , September 2016, , Pages 25-34
Abstract
In this paper, magnetic spin control using Spin and B-dot control laws have been studied in a lab environment. Evaluation of this control laws is done by a "three degrees of freedom air-bearing simulator". Due to the inherent simulator limitations, laboratory test results are visible only on one axis. ...
Read More
In this paper, magnetic spin control using Spin and B-dot control laws have been studied in a lab environment. Evaluation of this control laws is done by a "three degrees of freedom air-bearing simulator". Due to the inherent simulator limitations, laboratory test results are visible only on one axis. Therefore, to evaluate these three-axis laws precisely, evaluation modeling is discussed by comparing the simulator dynamic and kinematic equations with the results of laboratory experiments. After evaluation of the modeling process, simulation of three-axis control law is conducted. Since the validated model shares same basis with satellite model equations except the torque disturbances caused by the distance between the center of the mass and the center of the rotation, it can be assured that these control laws are suitable for three-axis control of a satellite. Test results indicate appropriate performance of control laws.
Hamed Arefkhani; Seyed Mohammad Mehdi Dehghan; Amir Hossein Tavakoli
Volume 9, Issue 2 , September 2016, , Pages 47-60
Abstract
In this paper, the three-axis magnetic attitude control using PD and LQR control laws have been studied in a lab environment. Evaluation of the magnetic attitude control with this control laws is done by a "three degrees of freedom air-bearing simulator". Developed dynamic and kinematic equations to ...
Read More
In this paper, the three-axis magnetic attitude control using PD and LQR control laws have been studied in a lab environment. Evaluation of the magnetic attitude control with this control laws is done by a "three degrees of freedom air-bearing simulator". Developed dynamic and kinematic equations to be used in actual simulator are evaluated by open loop test. Then control laws evaluated by comparing close loop simulation and laboratory test. Due to the inherent simulator limitations, magnetic attitude control only possible in the yaw axis. Laboratory test results indicate the improved and accurate performance of LQR control law for most satellite missions. Therefore by generalized LQR controller, three-axis simulation was performed for a satellite.
A.R. Aghalari; A. Kalhor; S. M. M. Dehghan; S. H. Cheheltani
Volume 7, Issue 3 , October 2014, , Pages 51-67
Abstract
The Agile Satellite Attitude Control System Simulator (ASACSS) is a laboratory system designed for the purpose of developing and testing attitude control algorithms in a low-risk, low-cost environment. In this paper, the design and development of the ASACSS is described, including hardware and software. ...
Read More
The Agile Satellite Attitude Control System Simulator (ASACSS) is a laboratory system designed for the purpose of developing and testing attitude control algorithms in a low-risk, low-cost environment. In this paper, the design and development of the ASACSS is described, including hardware and software. There are many papers that present a new mathematical technique or prove a new theory, but this study presents the design and development of a new experimental system. This simulator consists of four main components: 1) power supply system 2) on-board control system 3) supporting equipments and 4) monitoring computer. On-board control system includes a industrial computer, four single gimbal control moment gyros and a sensor for attitude determination. Supporting equipments include a platform for installing simulator subsystems, a semi-spherical air bearing and a pedestal. A high-speed wireless LAN connection enables remote command initiation, monitoring and data collection for post-experimental analysis. In this paper, The design and construction process of the simulator are described. More over some experimental results presented from the application of a simple PID attitude controller on the spacecraft simulator. Finally, experimental results are compared with those obtained from simulation.
Ehsan Daneshnia; Mehrzad Nasirian; S. Mohammad Mahdi Dehghan
Volume 5, Issue 4 , January 2013, , Pages 29-38
Abstract
One of the mostimportant issuesin theproductivityof thesatellites is the mode timingand the automatic writingof thescenarioon-boardof thesatellite with regard environmental conditions. In order to have the capability to make flight scenariosformissionssent fromgroundstationsormissions that aregenerated ...
Read More
One of the mostimportant issuesin theproductivityof thesatellites is the mode timingand the automatic writingof thescenarioon-boardof thesatellite with regard environmental conditions. In order to have the capability to make flight scenariosformissionssent fromgroundstationsormissions that aregenerated automatically, on board timing forecast along with the time to reach thestationor thephoto target will be necessary. on board automatic generation of thescenarioswill reduce the dependency of the satelliteto groundstation. Calculation of the satellite riseandsettimes,without thesatellite passesand orbitdisturbances simulation, would not be possible. This paperpresentsformulaforthesatellite passessimulation, algorithmandtime prediction computation modelingusing keplerianorbitalparametersandreduces the size ofthecalculation utilizing of semimajor axis of the orbit to be usedonthe boardof satellite. Toreduce thevolume ofcalculations,it will be necessary to use numericalmethods forfindingfunction minimums orroots. semimajor axis of the orbitwill decrease the numerical computation to a great extent using the algorithmpresentedinthis paper.
A. H. Tavakkoli; A. Kalhor; S. M. M. Dehghan
Volume 5, Issue 2 , July 2012, , Pages 59-68
Abstract
In this paper the performance of a three Degrees Of Freedom simulator is evaluated. This platform is considered as an important instrument generally used in performance tests of spacecraft attitude determination and control subsystem on the ground. A hemispherical air bearing is used to provide micro ...
Read More
In this paper the performance of a three Degrees Of Freedom simulator is evaluated. This platform is considered as an important instrument generally used in performance tests of spacecraft attitude determination and control subsystem on the ground. A hemispherical air bearing is used to provide micro gravity condition. Reaction wheels produce required control torques and an integrated sensor is used for attitude determination. Commanding and visualization of the platform in monitoring station are provided by a wireless LAN. PD, QEF and LQR controllers are designed and implemented for slew maneuver to show the ability of the simulator. The desired attitude accuracy is obtained using these controllers. The test results verify the designed controllers and show the ability and functionality of the system, as a simulator for evaluating attitude controllers.
