Space subsystems design: (navigation, control, structure and…)
Ali Kasiri; Farhad Fani Saberi; Vahid Joudakian
Volume 16, English Special Issue , November 2023, , Pages 1-23
Abstract
Many studies have investigated the problem of external disturbance rejection and also increasing the attitude control system's robustness against the parametric uncertainties. Due to stochastic properties, noise effect minimization becomes an interesting and challenging problem in the field of spacecraft ...
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Many studies have investigated the problem of external disturbance rejection and also increasing the attitude control system's robustness against the parametric uncertainties. Due to stochastic properties, noise effect minimization becomes an interesting and challenging problem in the field of spacecraft attitude control that has been underestimated, while control actuators and attitude sensors themselves are important sources of noise generation., the main purpose of this paper is to (i)control the satellite’s attitude and (ii)minimize the variance of output, simultaneously. The Minimum Variance controller, which is considered the simplest type of model predictive controller, has a powerful capability for minimizing the effects of output noise. This feature makes it a suitable control scheme for space-based high-resolution photography missions. so,, we described the conventional Minimum Variance regulator method at first, then an Incremental version of the regulator has been presented to solve the tracking problem. Finally, the generalized minimum variance controller which can control both minimum-phase and non-minimum-phase systems is derived for a high pointing accuracy spacecraft. The simulation results show the efficiency of the proposed controller to restrain the noise effects in a high-resolution tri-stereo imaging mission.
Space subsystems design: (navigation, control, structure and…)
Abbas Dideban; Alireza Ahangarani Farahani
Volume 16, English Special Issue , November 2023, , Pages 25-38
Abstract
This paper presents a new control methodology based on Continuous Time Delay Petri Nets (CTDPN) tool for the attitude control of satellite simulator. The graphical and mathematical features of this tool help the expert designer to design an appropriate controller using graphical model easily, and then ...
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This paper presents a new control methodology based on Continuous Time Delay Petri Nets (CTDPN) tool for the attitude control of satellite simulator. The graphical and mathematical features of this tool help the expert designer to design an appropriate controller using graphical model easily, and then apply the necessary changes to the mathematical model. In this approach, the controller gains are derived from the states and some other variables. Thus, the system states and variables must be available. The new gain tuning algorithm consists of three stages. First, A simulation environment is made for mathematical modeling based on the CTDPN tool and controller design. Secondly, using optimal methods, the controller gains are calculated at any given time and the data are collected. Finally, using the database, a relationship between the set of variables and the gains are derived. Experimental results indicate the promising performance of the controller in comparison to the conventional controller applied to the satellite simulator platform. The results indicate that the designed controller is robust against variation of parameters, as the controller gains are tuned based on the system state and variables.
Space subsystems design: (navigation, control, structure and…)
Alireza Ahangarani Farahani; Amirhossain Adami; Hamed Arefkhani
Volume 16, Issue 3 , September 2023, , Pages 79-89
Abstract
In this article, a new approach has been presented in the design of a satellite's status controller using reaction wheels. First, a non-linear controller whose gains depend on the state variables at any moment is proposed. In the first step, the process of extracting control coefficients using the GA ...
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In this article, a new approach has been presented in the design of a satellite's status controller using reaction wheels. First, a non-linear controller whose gains depend on the state variables at any moment is proposed. In the first step, the process of extracting control coefficients using the GA optimizer is described. Then, using the results of a number of tests, sufficient data for meta-modeling of the system is extracted and the relevant control gain functions are optimized using the data bank. The input of the mentioned function is the system states and its output is the control coefficients. Finally, a simulator platform was used to determine and control the position of the satellite based on the air bearing to evaluate the proposed approach. Laboratory test results show that the performance of the proposed method is up to 30% better than the classical PID controller with fixed coefficients.
Space subsystems design: (navigation, control, structure and…)
Niki Sajjad; Mehran Mirshams; Shahrokh Jaliian
Volume 13, Issue 3 , September 2020, , Pages 51-62
Abstract
This paper presents design, analysis and performance verification test of student microsatellite Attitude Determination and Control Subsystem (ADCS) . ADCS design and implementation procedure contains several various steps. There are four main test levels during simulation called “Model-in-the-Loop”, ...
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This paper presents design, analysis and performance verification test of student microsatellite Attitude Determination and Control Subsystem (ADCS) . ADCS design and implementation procedure contains several various steps. There are four main test levels during simulation called “Model-in-the-Loop”, “Software-in-the-Loop”, “Processor-in-the-Loop” and “Hardware-in-the-Loop”. This paper is a result of scientific and practical research during two years, on the student microsatellite, which is an eight-nation collaboration project among Asia-Pacific universities. In what follows, “Model-in-the-Loop” and “Processor-in-the-Loop” test and simulation will be discussed. The aim of this paper is to illustrate the result of these two tests and validate the ADCS design. In the end, it is demonstrated that designed control algorithms are precise enough to meet the student microsatellite ADCS requirements and they can be used in the next level of microsatellite development.
ehsan maani; Hossein Nejat Pishkenari; Amir Reza Kosari
Volume 11, Issue 3 , December 2018, , Pages 63-71
Abstract
In this paper, the combination of reaction wheels and thrusters is applied to attitude control of a satellite. First, governing equations of satellite attitude dynamics are given using quaternion and PID controller is designed based on the satellite quaternion to determine the applied control torque. ...
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In this paper, the combination of reaction wheels and thrusters is applied to attitude control of a satellite. First, governing equations of satellite attitude dynamics are given using quaternion and PID controller is designed based on the satellite quaternion to determine the applied control torque. By applying the reaction wheels physical constraints such as its maximum torque, its maximum momentum and maximum power on the desired torque, reaction wheels angular momentums and torques are found. The obtained results show that the unsaturated reaction wheels capabilities in attitude control. Results also show that the wheels saturation leads to error in control and increases the Euler angles and quaternions. Satellite thrusters are utilized to reaction wheels de-saturation and attitude control simultaneously.Three different strategies are proposed in this paper for wheels de-saturation using thrusters. Two well known methods, pulse width modulator (PWM) and pulse width pulse frequency (PWPF) modulator are used to attitude control using thrusters. All methods are compared together and the optimal method is proposed for the satellite attitude control. This paper results can be useful in design and control of different class of satellites.
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.
Farhad Fani Saberi; Mansor Kabganian; Alireza Fazlyab; Abbas Ajorkar
Volume 9, Issue 1 , May 2016, , Pages 25-35
Abstract
In this paper, a robust attitude control algorithm is developed based on backstepping-sliding mode control for a satellite using four reaction wheels in a tetrahedron configuration. In this method, asymptotic stability of the proposed algorithm has been proven in the presence of reaction wheels dynamic ...
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In this paper, a robust attitude control algorithm is developed based on backstepping-sliding mode control for a satellite using four reaction wheels in a tetrahedron configuration. In this method, asymptotic stability of the proposed algorithm has been proven in the presence of reaction wheels dynamic model based on Lyapunov theory. Then, in order to evaluate the performance of the proposed algorithm, a low-cost real-time prossecor in the loop test bed is provided. The presented test bed is capable of real-time assessing the attitude backstepping-sliding mode control algorithm. In this test bed, real-time modeling of satellite dynamic, environmental disturbances and reaction wheels are achieved in a simulator computer and the proposed control algorithm performance is investigated by implementing it in an electronic control board of the prossecor in the loop test bed.
Farhd Fani Saberi
Volume 8, Issue 3 , October 2015, , Pages 15-26
Abstract
In this paper, achieving of Stereo-Imaging scenario by a remote sensing satellite will be presented. Then a suitable attitude control system will be designed using 4 reaction wheels with pyramidal structure to fulfill large angle maneuvers of stereo-imaging scenario. The proposed attitude control system ...
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In this paper, achieving of Stereo-Imaging scenario by a remote sensing satellite will be presented. Then a suitable attitude control system will be designed using 4 reaction wheels with pyramidal structure to fulfill large angle maneuvers of stereo-imaging scenario. The proposed attitude control system provide the satellite with the capability of nadir pointing and large angle maneuvers to take different images of a predefined zone from different point of view. In order to verify the performance of the designed attitude control system, a low-cost real time hardware in the loop test bed will be constructed. The constructed test bed is capable of assessing attitude control algorithms in a real time conditions. In the proposed test bed, accurate and real time modeling of satellite dynamics, space conditions, reaction wheels and gyroscopes will be done by the Simulator computer. Finally, performance of the designed attitude controller to achieve stereo-imaging scenario is investigated by implementing the algorithm in the hardware in the loop test bed in a real time condition.
Ali Reza Aghalari; Ahmad Kalhor; Farhad Shamim
Volume 8, Issue 1 , April 2015, , Pages 73-77
Abstract
In this paper, a designing procedure of a Variable Speed Control Moment Gyro (VSCMG) for performing an agile maneuver in an attitude control simulator is described, then a prototype is fabricated and finally the test results are presented. The design of actuator mechanism is based on simulator limitations ...
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In this paper, a designing procedure of a Variable Speed Control Moment Gyro (VSCMG) for performing an agile maneuver in an attitude control simulator is described, then a prototype is fabricated and finally the test results are presented. The design of actuator mechanism is based on simulator limitations (power consumption, dimensions and weight, simplicity) and direction of produced torque.Two DC electrical motors are used for controlling the angular velocity of flywheel and the gimbal slew rate. The motors controller and driver units are designed and implemented, so that the maximum accuracy, minimum errors and best response time could be accessible. Structural Design is based on strength, stiffness, volume and weightalso Necessary analysis are performed using ANSYS. Finally the functional tests of actuator such as measuring the produced torque (using simulator and load transducer), accuracy of gimbal position and gimbal slew rate, accuracy of flywheel rotational speed and power consumption are performed and then the results are presented.
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. ...
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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.
F. Moosavi; J. Roshanian; R. Emami
Volume 6, Issue 1 , April 2013, , Pages 1-10
Abstract
This paper presents the control design for large angle and high rotation rates maneuvers using reaction cold gas thrusters. Navigation system provides suborbital attitude changes in terms of quaternion. Cold gas thrusters with pulse-width pulse-frequency modulation provide nearly proportional control ...
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This paper presents the control design for large angle and high rotation rates maneuvers using reaction cold gas thrusters. Navigation system provides suborbital attitude changes in terms of quaternion. Cold gas thrusters with pulse-width pulse-frequency modulation provide nearly proportional control torques. The use of quaternion as attitude errors for large angle feedback control in a suborbital capsule is investigated. Numerical simulations demonstrate the practical feasibility of a three-axis large angle maneuver.
Farhad Fani Saberi; Amir Eslami Mehrjardi
Volume 5, Issue 4 , January 2013, , Pages 39-45
Abstract
In this paper we are going to design an attitude control system for a Stereo-Imaging Remote Sensing Satellite using of four pyramidal reaction wheels. In this method, in order to provide the power requirements of the satellite by the energy stored in the reaction wheels, a power management law will be ...
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In this paper we are going to design an attitude control system for a Stereo-Imaging Remote Sensing Satellite using of four pyramidal reaction wheels. In this method, in order to provide the power requirements of the satellite by the energy stored in the reaction wheels, a power management law will be designed and added to the attitude control law to charge and discharge the wheels according to the preset profiles. Therefore, attitude control and power management of the satellite will be carried out simultaneously. In this method, while the satellite is in the light and the batteries are charged, the speed of the wheels increase up to the limited speeds and while the power requirements of the subsystems are inadequate, Power will be returned to the subsystems by reducing the speed of the wheels. The design of this system has been conducted to consider the effects of saturation of the wheels to prevent attitude deviations of satellite while power management is done. Simulation results show the good performance of the designed attitude control and power management system of the satellite.
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.
M. Navabi; N. Nasiri
Volume 3, Issue 2 , January 2011, , Pages 45-52
Abstract
Since last decades utilizing satellites in low earth orbits have had increasing tendency. These satellites experience the earth magnetic field due to their low altitude to the earth. The Earth magnetic intensity can be used in order to control the attitude of spacecraft utilizing the interaction between ...
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Since last decades utilizing satellites in low earth orbits have had increasing tendency. These satellites experience the earth magnetic field due to their low altitude to the earth. The Earth magnetic intensity can be used in order to control the attitude of spacecraft utilizing the interaction between the earth magnetic field and magnetic dipoles which are generated in the body of satellite. First of all, for using this phenomenon the magnitude and direction of the Earth magnetic field have to be obtained. There are various ways in order to simulate the earth magnetic field, that the most accurate one is utilizing the harmonic coefficients and mathematical model of the earth magnetic field. In this study, the earth magnetic field is modeled based on the 10thgeneration of the IGRF coefficients and the results are verified with the most valid reference. Due the Earth magnetic field is used in order to attitude control of a spacecraft, it is necessary to transform the results into the spacecraft Body frame. This transformation can be obtained utilizing linear and nonlinear transformation. In the next step, based on the comparison of the results of the spacecraft attitude dynamics utilizing linear and nonlinear transformation the validity margin of linear transformation is studied.
S.H. Miri Roknabadi; M. Mirshams; A. A. Nikkhah
Volume 2, Issue 2 , July 2009, , Pages 61-68
Abstract
This paper presents a technical note of mathematic model, design and manufacturing steps of a Reaction Wheel, one of the most important active actuators of satellite. After that Reaction Wheels are tested for the satellite simulator of K.N.Toosi University of Technology, Iran. There were some requirements ...
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This paper presents a technical note of mathematic model, design and manufacturing steps of a Reaction Wheel, one of the most important active actuators of satellite. After that Reaction Wheels are tested for the satellite simulator of K.N.Toosi University of Technology, Iran. There were some requirements and restrictions such as needed maximum torque and control accuracy for attitude maneuver, receivable power, voltage and current. Accordingly fundamental components of Reaction Wheel have been designed and selected. Wheel, motor, bearings and retentive are the significant components. At the rest of the paper, the substantial parameters of the Reaction Wheels are confirmed by a new test set. The results of test guarantee a satisfactory stabilization and accurate maneuver.
A. R. Aghalari; A. Kalhor; S. M. Dehghan; A. Abedian
Volume 2, Issue 1 , April 2009, , Pages 13-23
Abstract
In this paper, a designing procedure of Single Gimbal Control Moment Gyro (SGCMG) for performing an agile slew maneuver in a microsatellite is described, then a prototype is fabricated and finally the test results are presented. The design of actuator mechanism is based on simplicity, direction of produced ...
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In this paper, a designing procedure of Single Gimbal Control Moment Gyro (SGCMG) for performing an agile slew maneuver in a microsatellite is described, then a prototype is fabricated and finally the test results are presented. The design of actuator mechanism is based on simplicity, direction of produced torque, minimum volume and weight. A DC electrical and a stepper motor with accuracy of 0.024 degree are used for controlling the angular velocity of flywheel and the gimbal slew rate, respectively. The motors controller and driver units are designed and implemented, so that the maximum accuracy, minimum errors and best response time could be accessible. The flywheel design is based on the required angular momentum which should be stored. The gimbal consists of two in-line beams which are attached to bearing in one side and momentum wheel system in the other side. A specific approach was considered to avoid any deformation in beams in consequence of mounting the momentum wheel system.
H. Bolandi; F. Fani- Saberi; B. Ghorbani-Vaghei
Volume 1, Issue 2 , December 2008, , Pages 9-15
Abstract
In this paper, the main stereo-imaging methods by high resolution satellites, including Along-Track and Across-Track, have been evaluated and then we will combine the two main stereo-imaging configurations of along track and across track as a new idea to obtain the advantages of both methods. In the ...
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In this paper, the main stereo-imaging methods by high resolution satellites, including Along-Track and Across-Track, have been evaluated and then we will combine the two main stereo-imaging configurations of along track and across track as a new idea to obtain the advantages of both methods. In the proposed stereo-imaging scenario, fast and simultaneous large maneuvers of the satellite around pitch and roll axes is one of the versatile methods. So, highly nonlinear characteristics of the governing equations because of large angle slewing maneuvers are very effective on pointing accuracy and stability and should be considered to design control laws. The purpose of this paper is to design a nonlinear control method using four reaction wheels based on PD controller that can be used to perform a spacecraft large angle maneuver using quaternion attitude variables. The configuration of reaction wheels in the simulated spacecraft has been arranged as a skewed four-wheel reaction. Reaction wheels unloading is also accomplished through the use of three magnetic torquers to prevent the speeds of the reaction wheels exceeding their designed limits, largely as a result of the action of secular components of disturbing torque. Simulation study has verified the performance and effectiveness of the proposed algorithm to achieve the proposed stereo-imaging scenario.
H. Bolandi; B. Ghorbani Vaghei
Volume 1, Issue 1 , September 2008, , Pages 11-19
Abstract
In this paper, attitude control system of an axisymmetric satellite will be designed in such a way that required stability is provided with slow spinning about yaw axis. In this regard, dynamic of motion and coupling between satellite’s axes is modeled. As a result, a closed form formula is yielded ...
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In this paper, attitude control system of an axisymmetric satellite will be designed in such a way that required stability is provided with slow spinning about yaw axis. In this regard, dynamic of motion and coupling between satellite’s axes is modeled. As a result, a closed form formula is yielded included moment of inertia ratio, angular velocity about yaw axis and pointing accuracy of control system. Then, magnetic control is designed for providing capture range of gravity gradient stabilization and requirements of pointing accuracy. Finally, fine performance of designed control system will be illustrated with simulation based on specification of a near axisymmetric satellite.
