Space systems design (spacecraft, satellites, space stations and their equipment)
Ghasem Kahe; Mehdi Alemi Rostami
Volume 15, English Special Issue , May 2022, , Pages 45-53
Abstract
Diversity in both hardware and software plays an essential and unmatched role in increasing the reliability of redundant systems, especially in safety and mission critical applications. The onboard computer of satellites and the flight computer of spacecrafts, which are ultra-reliable systems, utilize ...
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Diversity in both hardware and software plays an essential and unmatched role in increasing the reliability of redundant systems, especially in safety and mission critical applications. The onboard computer of satellites and the flight computer of spacecrafts, which are ultra-reliable systems, utilize various hardware platforms for their redundant architecture to resolve a common cause failure (CCF) problem. Furthermore, the software is also developed by separate teams based on different software platforms to mitigate the specification and design flaws, and implementation mistakes. This paper focuses on modelling the diversity of redundant architectures in space systems using CCF modelling and Markov reliability analyzing. The proposed scheme is explored in two types of applications: mission critical applications (with long mission time) and safety critical applications (with short mission time). Analytical and simulation results show the effectiveness of diversity in increasing the reliability of these systems. Since a significant percentage of all failures appear as common cause failures, which restrict reliability improvement through similar redundant modules, achieving ultra-reliability necessitates considering diversity in these systems.
M. Ebrahimi; J. Jodey; J. Roshanian
Volume 1, Issue 1 , September 2008, , Pages 47-56
Abstract
Abstract-Multidisciplinary Design Optimization (MDO) approaches have significant effects on aerospace vehicle design methodology. In designing next generation space launch systems, MDO processes will face new and greater challenges. Needs to improve conceptual design capabilities have required an increase ...
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Abstract-Multidisciplinary Design Optimization (MDO) approaches have significant effects on aerospace vehicle design methodology. In designing next generation space launch systems, MDO processes will face new and greater challenges. Needs to improve conceptual design capabilities have required an increase in the fidelity of empirical disciplinary models, improved design solutions and optimization methods, and reduced workload and design cycle time through advanced frameworks. Such a procedure could identify feasible designs and generate comparison and sensitivity data during optimization.This study uses a System Sensitivity Analysis method to optimize multidisciplinary design of a two-stage Small Solid Propellant Launch Vehicle (SSPLV) based on minimum launch mass. Suitable design variables and technological and functional constraints are considered, both at the system and discipline levels. Propulsion, weight, geometry and trajectory simulation disciplines are used in an appropriate combination. A Generalized Sensitivity Equation (GSE) is derived and solved, and the results of this equation are used for optimization. Comparing the results with the well known gradient based optimization methods proves the ability of the SSA method to reduce computation time.
Fariba Razipour; M. Najafi-Asfad
Volume 4, Issue 2 , January 2012, , Pages 47-62
Abstract
During Persian Gulf war (1990), space assets played a valuable role and their usefulness was revealed for the first time. Space technology creates an infrastructure that helps military strategies. It helped a lot in some battles such a Afghanistan, Siberia and Cosovo war.In this article we are going ...
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During Persian Gulf war (1990), space assets played a valuable role and their usefulness was revealed for the first time. Space technology creates an infrastructure that helps military strategies. It helped a lot in some battles such a Afghanistan, Siberia and Cosovo war.In this article we are going to explain the existing rules on international humanitarian law and other rules and have some recommendations to protect outer space from military threats.
H. Dehghani; A. Reyvandi; M. B. Fallah-Pour; K. Mousazadeh
Volume 6, Issue 1 , April 2013, , Pages 47-56
Abstract
SAR radar imaging system is a supplement for electro optic remote sensing system and has been used over the past two decades. Understanding the behavior of these systems is difficult, because the complexity of these systems, especially in the mapping of the signal space to image space. This problem, ...
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SAR radar imaging system is a supplement for electro optic remote sensing system and has been used over the past two decades. Understanding the behavior of these systems is difficult, because the complexity of these systems, especially in the mapping of the signal space to image space. This problem, development and use of this technology from the performance perspective and opposing with it from the performance passive defense, severely limited. In this paper a model for the performance of SAR imaging systems is provide. This model is like the impulse response function for linear systems independent of time. In other words, the proposed model is the impulse response of two-dimensional SAR systems and byusing it the SAR imaging process can be simulated. Using this model, many phenomena such as speckle noise shaping, can be described and the factors and parameters that are effective in the imaging system can be analyzed. Validity of the two-dimensional impulse response or functional model that presented in this paper, by comparing the results obtained in this paper and the expected results reported in reliable sources in this area has been proved.
Zahra Samadi Khoshkho; Mehdi Mortazavi-Bek; Farhad Fani Saberi
Volume 9, Issue 1 , May 2016, , Pages 47-56
Abstract
In this paper, an adaptive controller based on decentralized minimal control synthesis is designed n order to control an attitude of specific remote sensing satellite. The main design purposes are performing spinning, three axis and large angle maneuver as well as achieving a stable system and tracking ...
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In this paper, an adaptive controller based on decentralized minimal control synthesis is designed n order to control an attitude of specific remote sensing satellite. The main design purposes are performing spinning, three axis and large angle maneuver as well as achieving a stable system and tracking the reference attitude trajectory in the presence of uncertainties. In the design process, the effects of internal and external disturbances, nonlinearities in the satellite dynamic and the accurate model of actuators are regarded. Four reaction wheels with pyramidal structure are modeled as the actuators to accomplish an attitude maneuver. So the exact reaction wheels’ model with regarding the maximum voltage, current, allowable angular velocities and power of wheels is developed. The simulation results show an acceptable performance of controller in the presence of exacts actuators’ model, external and internal disturbances and uncertainties in the satellite parameters.
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 ...
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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.
amirhossein tavakoli; ali faghihi; S.Mohammad Mehdi Dehghan
Volume 10, Issue 1 , June 2017, , Pages 47-53
Abstract
Simulating environmental conditions for the satellite attitude sensors is a fundamental requirement of hardware in the loop tests of attitude determination and control subsystem. In this paper, a new design for simulating sun vector and magnetic vector is presented. The operating environment for attitude ...
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Simulating environmental conditions for the satellite attitude sensors is a fundamental requirement of hardware in the loop tests of attitude determination and control subsystem. In this paper, a new design for simulating sun vector and magnetic vector is presented. The operating environment for attitude sensors is simulated using a sun simulator, a two-degree-of-freedom table for changing the attitude of the sun sensor, and a three-axis Helmholtz coil. The sensors measurements showed that with this setup, the sun and magnetic vectors can be created with an acceptable accuracy using the orbital position and the attitude of the satellite. So, the test bed can be used for attitude determination of hardware in the loop tests.
Danial Boostan
Volume 11, Issue 3 , December 2018, , Pages 47-61
Abstract
Prediction of satellite orbital position is a critical requirement for all satellite ground stations. In this paper, a new viewpoint for predicting orbital position of satellites is presented. In contrast to traditional methods which are based on Kepler's law, the proposed method, is solely based on ...
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Prediction of satellite orbital position is a critical requirement for all satellite ground stations. In this paper, a new viewpoint for predicting orbital position of satellites is presented. In contrast to traditional methods which are based on Kepler's law, the proposed method, is solely based on past observation of a given satellite. In contrast to traditional algorithms which have neglected some of the orbital perturbations, the most important feature of this method is considering all orbital perturbations by using real data. TLEs (Two Line Element sets) are the most available real data and are used in this research as the main data source. Using the capability of neural networks for time series prediction over available data, results in a fast and accurate orbital position predictor. The comparison between the output of our proposed method, SPG4 (Simplified General Perturbation version 4) propagator and real orbital position of a given satellite, shows the effectiveness of this algorithm.
Space systems design (spacecraft, satellites, space stations and their equipment)
Hojat Ghasemi; Seyed Mohammadreza Mahmoudian; Noordin Qadiri Massoom; S. Rashad Rouholamini; Pouria Mikaniki; Asghar Azimi
Volume 16, Issue 1 , March 2023, , Pages 47-58
Abstract
The aim of the present research is to obtain the ability to use the cryogenic propellant engines on a laboratory scale. In this regard, it is necessary to build some experimental motors and investigate the their performance parameters. The liquid oxygen as a common oxidizer and ethanol as a green fuel ...
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The aim of the present research is to obtain the ability to use the cryogenic propellant engines on a laboratory scale. In this regard, it is necessary to build some experimental motors and investigate the their performance parameters. The liquid oxygen as a common oxidizer and ethanol as a green fuel have been selected as propellant components. The engine is designed to produce 400 kgf force at the nominal condition. The pintle type injector has been chosen in which liquid oxygen and fuel are flowed in the axial and radial directions, respectively. The combustion chamber has been protected against overheating by applying the regenerative cooling. However, the laboratory feature of the engine design has provided the using of water instead the cooling propellant. All main components of the engine such as injector, igniter, and flow controllers, are examined by the cold tests. A comprehensive test facility is designed and set up for hot fire tests in which the performance of almost all parameters can be evaluated. Fifteen fire tests have been performed. Maximum obtained pressure and evaluated combustion efficiency were about 75% of design values.
S. Shahmirzai Jashoghani; M. Nosratollahi
Volume 4, Issue 1 , July 2011, , Pages 49-60
Abstract
In this research optimal trajectory of lunch vehicle based on maximizing payload is being attended. At first, motion of missile concluding modeling of environment, atmosphere, gravity, mass, motion equations and aerodynamic coefficients would be simulated. Then procedure of an optimized design by using ...
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In this research optimal trajectory of lunch vehicle based on maximizing payload is being attended. At first, motion of missile concluding modeling of environment, atmosphere, gravity, mass, motion equations and aerodynamic coefficients would be simulated. Then procedure of an optimized design by using optimal control theory would be described. Applying variational calculus and mathematical modeling of optimization problems would lead project to a two point boundary condition problem which would be solved by numerical solutions such as steepest descent. At last a code would be generated in which optimal trajectory of missile calculated by using indirect optimal control and steepest descent numerical solution. An interesting point in this article is that some variables are used both as state and control variables. Hence state control variables here are divided to two groups, slow state variables concluding ones which are only state variables, and fast state variables concluding ones which are both state variables and control variables simultaneously. Solution for such control problems is described here.
M. Mirshams; S. Irani; A. M. Akhlaghi; H. Naseh
Volume 5, Issue 2 , July 2012, , Pages 49-57
Abstract
The goal of this paper is presenting a methodology for reliability allocation to launch vehicle subsystems using Analytical Hierarchy Process (AHP) method in conceptual design phase. In this methodology, the goal function is reliability and the main considered criterions are technology, complexity, operational ...
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The goal of this paper is presenting a methodology for reliability allocation to launch vehicle subsystems using Analytical Hierarchy Process (AHP) method in conceptual design phase. In this methodology, the goal function is reliability and the main considered criterions are technology, complexity, operational time of each subsystem and cost. For applying AHP method to launch vehicle subsystems reliability allocation, a Matlab code( for investigating compatibility and determining allocation weight factors by employing Matrix Eigen Vector Method) and a Excel sheet( for forming the comparison matrix) are employed. To this point, by using the outcomes of liquid-propellant launch vehicle conceptual design software (LVCD) which developed by authors, the launch vehicle specifications and operational time of each subsystems is derived and is feed to this methodology as input. The results of applying this method to launch vehicle reliability allocation for the second stage of a launch vehicle, shows the error of this method below 2%. It is clear that this small error in reliability issues in conceptual design phase is acceptable.
M. Jafari -Nadoushan; A. Novinzadeh
Volume 6, Issue 3 , October 2013, , Pages 49-54
Abstract
In this paper design of transfer trajectory from Earth park orbit to a halo orbit around L1 of Earth-Moon system and return trajectory from halo orbit to the Earth are investigated. Since satisfying constraints and boundary conditions at the end of trajectory is an important point in trajectory design, ...
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In this paper design of transfer trajectory from Earth park orbit to a halo orbit around L1 of Earth-Moon system and return trajectory from halo orbit to the Earth are investigated. Since satisfying constraints and boundary conditions at the end of trajectory is an important point in trajectory design, we deal with a two point boundary value problem. Considered constraints in this paper include height, orthogonality of position and velocity vectors for reducing required Del-V for orbital transfer and flight path angle. Due to complex dynamics of three body problem and also in order to satisfying these constraints and suitable trajectory design, the multiple shooting methods based on differential correction is used.
M. HadiDoolabi; A.M. Gorji; H.R. Tajik
Volume 7, Issue 2 , July 2014, , Pages 49-61
Abstract
This study, focuses to simulate separation process in different launchers numerically using fluent software. In present case, an aerodynamic equations coupled with rigid body dynamics, because of resultant aerodynamic forces and gravity, is developed to simulate the detachment motion of strap-on boosters. ...
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This study, focuses to simulate separation process in different launchers numerically using fluent software. In present case, an aerodynamic equations coupled with rigid body dynamics, because of resultant aerodynamic forces and gravity, is developed to simulate the detachment motion of strap-on boosters. As can be seen from the results, by changing in booster elongation and changing in operation mach number and the effect of expansion waves from the core rocket and the booster, separation trajectory follows safe separation or collision between core and booster.
Maryam Kiani; Amir Shakouri; S.H Pourtakdoust; Mohammad Sayanjali
Volume 11, Issue 1 , June 2018, , Pages 49-57
Abstract
A new strategy is presented for the optimal transfer of non-coplanar elliptical orbits based on sequential multi-Lambert trajectories. The proposed method tries to minimize the control effort during the orbit transfer. The main advantages of the proposed method include transfer between arbitrary initial ...
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A new strategy is presented for the optimal transfer of non-coplanar elliptical orbits based on sequential multi-Lambert trajectories. The proposed method tries to minimize the control effort during the orbit transfer. The main advantages of the proposed method include transfer between arbitrary initial and final orbits, utilizing desired number of impulses, and covering all possible transfer trajectories to achieve the target. The position and time instant of impulses are considered as the design variables which determine utilizing the well-known optimization method of pseudo-Newton. Performance of the proposed method is investigated and verified through some numerical simulations. It is also shown that the proposed method converges to the celebrated Hahmann’s maneuver in transfer between two coplanar orbital orbits.
Mehran Nosratollahi; Ahmad Soleimani
Volume 13, Issue 1 , March 2020, , Pages 49-60
Abstract
In this paper, the performance of fluid momentum controller (FMC) actuators in satellite temperature management is investigated based on two pyramidal and 3-axis proposed configurations. In this regard, the temperature of different satellite surfaces with fluid actuators and without actuators in an orbital ...
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In this paper, the performance of fluid momentum controller (FMC) actuators in satellite temperature management is investigated based on two pyramidal and 3-axis proposed configurations. In this regard, the temperature of different satellite surfaces with fluid actuators and without actuators in an orbital period of satellite is investigated and the results are compared to each other. For FMC actuators that are closed as a loop, a Moving Reference Frame (MRF) is used and the flow inside the actuators is laminar. The effect of fluid angular velocity of actuators on the temperature of satellite surfaces with two different angular velocity has been investigated and time-dependent heat flux is applied to the satellite surfaces. The results indicate that in the pyramidal configuration, the decrease in the temperature of the satellite wall surfaces is influenced by two parameters: fluid angular velocity and orbital period of satellite, but in the critical conditions, the 3-axis configuration can carry out this temperature management more quickly.
Remote sensing
Mohammad Hassan Vahidnia; Hossein Aghamohammadi
Volume 13, Issue 4 , December 2020, , Pages 49-58
Abstract
Studying vegetation status is one of the most important environmental issues. Using contemporary and field methods in this regard will cost a lot of time and money. Remote sensing technology and satellite image processing is a solution that can facilitate such difficult processes. In this study, remote ...
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Studying vegetation status is one of the most important environmental issues. Using contemporary and field methods in this regard will cost a lot of time and money. Remote sensing technology and satellite image processing is a solution that can facilitate such difficult processes. In this study, remote sensing technology will be integrated with web geographic services to provide users with adequate analysis of the growth of the plants and their changes based on vegetation indices in the shortest possible time. Important technologies used for this purpose are ENVI IDL, Google Map API, JavaScript, and ASP.NET. The service was successfully implemented and was employed for Landsat satellite images. In order to evaluate the performance of the service at different points and with a different number of images, the timeliness of the NDVI vegetation index was prepared. The processing time evaluation also showed that by increasing the number of satellite images the processing time will increase linearly.
Space systems design (spacecraft, satellites, space stations and their equipment)
Armin Azodi; Meysam Mohammadi Amin; Saeed Mahmoudkhani
Volume 15, Issue 3 , September 2022, , Pages 49-66
Abstract
In the present work, the frequency-domain aeroelastic stability analysis of space launch vehicle body in the flight condition of initial launch phase is presented for a range of geometric parameters, structural characteristics, and other parameters such as thrust force. The aeroelastic model is derived ...
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In the present work, the frequency-domain aeroelastic stability analysis of space launch vehicle body in the flight condition of initial launch phase is presented for a range of geometric parameters, structural characteristics, and other parameters such as thrust force. The aeroelastic model is derived using structural assumed modes and quasi-steady aerodynamics. The pressure distribution of subsonic flow on the 3D configuration is determined by boundary element method. Non-uniform Euler-Bernoulli beam including torsion spring junctions along the body with free-free ends is used to model the structure, and its modal analysis is performed by finite difference method. Concluded results illustrate variation in parameters not only could vary the aeroelastic instability boundary, but also might cause the instability type changed (from divergence to flutter), which its main reason is replacement the second instability of the aeroelastic system with the first one. Furthermore, it is demonstrated that the follower thrust force restricts the aeroelastic stability but maintains the instability type.
space policy
Hadi Jalili
Volume 17, Issue 1 , March 2024, , Pages 49-62
Abstract
In this paper, the models of space technology development in regional countries have been studied first, and the main criteria of each of these models have been classified. In this research, by ignoring the leading countries such as USA, Russia, European Union, China, Japan and India, the prominent countries ...
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In this paper, the models of space technology development in regional countries have been studied first, and the main criteria of each of these models have been classified. In this research, by ignoring the leading countries such as USA, Russia, European Union, China, Japan and India, the prominent countries of the region in the field of space technology have been investigated. These countries include the occupying regime of Al-Quds, South Korea and Turkey in the first degree of importance and the United Arab Emirates, North Korea, Kazakhstan and Pakistan in the second degree of importance. Then, SWOT analysis has been done for the space technology trends in the country, and by considering the requirements of the space technology development models, the proper development model has been introduced with the relevant requirements. According to the obtained results, the indigenous development model is the best space technology development model for the country, and one of the most important infrastructures needed in this model is to have a suborbital laboratory and a minimal mass orbital launch service.
A. Tavakoli; M. Nikusokhan; J. Roshanian; M. Mirshams
Volume 2, Issue 2 , July 2009, , Pages 51-60
Abstract
Design of launch vehicle (LV) trajectory is among the problems in which the use of optimization is of high significance. Implementing optimization using optimal control problem leads to a two point boundary value problem (TPBVS) that can be solved only numerically. On the other hand, development of optimal ...
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Design of launch vehicle (LV) trajectory is among the problems in which the use of optimization is of high significance. Implementing optimization using optimal control problem leads to a two point boundary value problem (TPBVS) that can be solved only numerically. On the other hand, development of optimal control problem for sophisticated model is very intricate and therefore simulation-based optimization plays an Important role in these problems. In this paper, a LV trajectory defining control input as a parameteic function with linear, Spline and Bezier functions was designed and its fuel consumption was optimized using Genetic Algorithm. Result analyses speculate that Bezier and Spline functions arrives to favorable consequences in terms of meeting terminal Boundary Condition (B. C), optimality of LV payload and also number of optimization parameters.
M. Navabi; M. Barati
Volume 5, Issue 1 , April 2012, , Pages 51-59
Abstract
Relative motion of satellites in a formation can be studied in several forms of dynamics models. In this paper, some of the most applicable models each implying particular assumptions, constraints and specifications are described in Cartesian and orbital element spaces. Despite the significant applications ...
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Relative motion of satellites in a formation can be studied in several forms of dynamics models. In this paper, some of the most applicable models each implying particular assumptions, constraints and specifications are described in Cartesian and orbital element spaces. Despite the significant applications of models based on linear equations of motion in modeling orbital rendezvous and ducking maneuvers, it is shown that the modeling errors of these simplified models limits their application in long term missions such as formation flying. Nonlinear equations of relative motion are derived in addition to 6 other dynamical models to simulate a low earth two satellite formation with projected circular relative orbit. Models are evaluated under the effects of non-spherical earth perturbation, relative distance between the satellites, and the eccentricity of the chief orbit. Analyzing the results of simulations emphasizes the importance of accuracy of the system.
Mohammad Tahaye Abadi; Mehdi AlizadehYazdi; Mohammad Ali Farsi; Mohammad Ebrahimi
Volume 7, Issue 4 , January 2015, , Pages 51-62
Abstract
The paper concerns with the experimental analysis of the pyroshock wave propagation in the structure of Kavoshgar's payloadon the ground. The source of waves is the explosion of pyrotechnic materialacting as the actuator of separation mechanism for the payload subsystems. The shock sensors are attached ...
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The paper concerns with the experimental analysis of the pyroshock wave propagation in the structure of Kavoshgar's payloadon the ground. The source of waves is the explosion of pyrotechnic materialacting as the actuator of separation mechanism for the payload subsystems. The shock sensors are attached in different locations of structure to measure the acceleration amplitude along three orthogonal directions after the activation of pyrotechnic material.The experimental setup is used for measurement of the acceleration history as well as the evaluation of the shock response spectrum at specific locations during two-stage separation of payload subsystems. The experimental acceleration record is evaluated to eliminate the noise signals and incorrect data. The variations of shock  response at different payload locations are evaluated to determine the amplitude attenuation of the wave passing through the structure body and joints. The measured data are also employed to determine the working condition and design criteria for the equipment of Kavoshgar payload.
Javad Salem; hossein pilaram; seyyed mohammad alavi
Volume 9, Issue 4 , April 2017, , Pages 51-63
Abstract
For the detection of and tracking thelow earth orbit Satellites (LEO), there are different methods such as optic, laser and radar tracking, among which radar tracking is the best. Since the common linear tracking filters deployed in available radars are not able to estimate the position of the non-linear ...
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For the detection of and tracking thelow earth orbit Satellites (LEO), there are different methods such as optic, laser and radar tracking, among which radar tracking is the best. Since the common linear tracking filters deployed in available radars are not able to estimate the position of the non-linear dynamic satellites, it is advisable to use non-linear filters. In this paper, firstly, the satellite motion path around the earth as well as radar observations are produced by the STK software. Accordingly, the samples are fed to non-linear Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF). Finally, the performance of the aforementioned filters is studied through evaluation of RMS position and estimation errors. Simulation results demonstrate that the Unscented Kalman filter has a better performance in terms of accuracy with respect to the Extended Kalman filter. In addition, using this method, theerror of observations decreases 50% along the range and 70% along the azimuth and elevation.
Space subsystems design: (navigation, control, structure and…)
Milad َAzimi; Samad Moradi
Volume 14, Issue 3 , September 2021, , Pages 51-63
Abstract
The free and forced vibration analysis of a rotating large flexible structure with a single crack is investigated using the Homotopy Perturbation Method (HPM). The crack is modeled with a torsional spring element on a structure that follows the Euler-Bernoulli theory. The nonlinear equations of motion ...
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The free and forced vibration analysis of a rotating large flexible structure with a single crack is investigated using the Homotopy Perturbation Method (HPM). The crack is modeled with a torsional spring element on a structure that follows the Euler-Bernoulli theory. The nonlinear equations of motion of the co-rotational system considering centrifugal forces are derived using the calculus of variation and the Assumed Mode Method (AMM). Applying the Galerkin method, the spatial domain is extracted and the time domain is transformed into a second-order nonlinear differential equation. The results of time response, phase plane, and bifurcation diagrams for different functional parameters variations such as base angular velocity, crack position and stiffness have been analyzed. Moreover, it is shown that as the base angular velocity increases, a tensile force appears along the cracked structure axis, stiff it, and shifts the backbone to the right, this can highly affect the nonlinear features of the system.
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.
Space subsystems design: (navigation, control, structure and…)
Reza Sheikhbahaei; Saeed Khankalantary
Volume 14, Issue 4 , December 2021, , Pages 51-59
Abstract
In this study, on the basis of proportional navigation strategy, design of explicit optimal guidance law for missiles tracking maneuvering targets in three-dimensional space using model predictive control is addressed. The model predictive control employs a model to predict the future process behavior ...
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In this study, on the basis of proportional navigation strategy, design of explicit optimal guidance law for missiles tracking maneuvering targets in three-dimensional space using model predictive control is addressed. The model predictive control employs a model to predict the future process behavior and calculates an optimal control input at each time step through the optimization of an objective function. Generalized model predictive control approach, employed in this study, solves the optimization problem offline to obtain the closed form optimal control law. In this paper, firstly, the equations describing the missile-target relative motion kinematics are formulated. Then, the optimal control law, as an explicit function of the state vector is obtained. The evaluation of the proposed scheme is studied by the comparison of the simulation results with the augmented proportional navigation system. Simulation studies, in three different scenarios, demonstrates appropriate performance for the proposed guidance system specially against maneuvering targets.
