S. Khodadadiyan; R. Farokhi; D. Ramesh
Volume 7, Issue 2 , July 2014, , Pages 75-83
Abstract
The aim of the paper is to describe a methodology of damage detection in the liquid propellant engine which is based on artificial neural networks in combination with stochastic analysis. It is assumed that the liquid propellant engine have faulty data collection system. Then a filtering algorithm for ...
Read More
The aim of the paper is to describe a methodology of damage detection in the liquid propellant engine which is based on artificial neural networks in combination with stochastic analysis. It is assumed that the liquid propellant engine have faulty data collection system. Then a filtering algorithm for elimination perturbation data has been applied .The damage is defined as fuel and oxidizer channels clogging up. The key stone of the method is feed-forward multi layer network with back propagation algorithm. It is impossible to obtain appropriate training set for real engine, therefore stochastic analysis using mathematical model is carried out and dynamic simulation is made to get training set virtually. Engine channels clogging up leads to unwanted variation of pressure, flow rate of oxidizer and fuel and other main parameters of engine. Then variations considered as best input data for damage detection. The methodology was carried out using laboratory test.
GPS and navigation GPS)، GLONASS، GALILEO
Mohsen Shamirzaei; Mehran Mir Shams
Volume 14, Issue 3 , September 2021, , Pages 75-90
Abstract
The main task of the study is to estimate the position error in an inertial navigation system by integrating it with the visual system. The case study is a spacecraft that must accurately measure its position relative to a predetermined landing point. The spacecraft is assumed to be augmented GNSS navigation. ...
Read More
The main task of the study is to estimate the position error in an inertial navigation system by integrating it with the visual system. The case study is a spacecraft that must accurately measure its position relative to a predetermined landing point. The spacecraft is assumed to be augmented GNSS navigation. Therefore, when satellite signals are dropped out or when landing on a moving marine platform, the data of the vision navigation system replaces the information of the satellite navigation system and improves the accuracy of the spacecraft navigation system. An Extended Kalman filter has been used to integrate inertial and vision navigation system information. In addition, the output data of the vision system, in order to be used in the Kalman filter measurement equations, is first processed by the recursive least square filter. The relevant relations are given and based on the results of software simulation, the efficiency of the proposed method is shown.
Payman Torabi; Abolghasem Naghash
Volume 9, Issue 2 , September 2016, , Pages 77-83
Abstract
This paper presents a new methodology for a quick and efficient numerical determination of the condition for repeat ground tracks to be employed in an orbital optimization design methodology. This methodology employs the simplicity and reliability of the epicyclical motion condition for a repeat ground ...
Read More
This paper presents a new methodology for a quick and efficient numerical determination of the condition for repeat ground tracks to be employed in an orbital optimization design methodology. This methodology employs the simplicity and reliability of the epicyclical motion condition for a repeat ground track to find a semimajor axis for a given repetition cycle and inclination. Then the semimajor axis is re fined for application to any elliptical motion. This methodology was discovered by comparing two recent methods in addition to a new proposed method offered in this paper investigating both nonlinear algebraic and polynomial formulations of the governing repeat-ground-track condition relationship. A lesser known simplified method is used for preliminary solution refinement. The advantages and disadvantages of each approach are weighed with each method ’s reliability, performance, and computational ease based on a case study. From these criteria, one method is recommended for use in repeat-ground-track orbit design optimization methodology.
Space New Technologies
Hassan Naseh; Mostafa Jafarpanah
Volume 15, Issue 3 , September 2022, , Pages 79-92
Abstract
The purpose of this paper is to present the cost estimation and optimization of space propulsion systems. Thus, choosing optimal propulsion system (from fuel and oxidizer aspect) is done in order to increase the efficiency and decrease the cost. Also, human resource cost and technology development time ...
Read More
The purpose of this paper is to present the cost estimation and optimization of space propulsion systems. Thus, choosing optimal propulsion system (from fuel and oxidizer aspect) is done in order to increase the efficiency and decrease the cost. Also, human resource cost and technology development time based on the consideration of labor cost effect on the personals motivation have been optimized. To this end, cost estimation and optimization algorithm has been drawn and suggested. The suggested algorithm has two steps. The first step in the algorithm is concern to cost estimation for seven fuel and oxidizer components. In the second step, labor cost and project implementation time is estimated and optimized based on the optimal space propulsion system derived from the previous step. Here, the objective functions are propulsion system technology development cost and time. On the other hand, the purpose is to consider the salary enhancement and consequently efficiency enhancement, time decrease and cost decrease.
M. Navabi; ُshahram Hosseini
Volume 12, Issue 4 , December 2019, , Pages 79-89
Abstract
افزایش دقت و پایداری در تخمین آنلاین مدل یک فضاپیما، به دلیل همزمانی وجود نامعینی در دینامیک سیستم و نویز در خروجی حسگرهای وضعیت، یکی از چالشهای کنترل وضعیت است. ...
Read More
افزایش دقت و پایداری در تخمین آنلاین مدل یک فضاپیما، به دلیل همزمانی وجود نامعینی در دینامیک سیستم و نویز در خروجی حسگرهای وضعیت، یکی از چالشهای کنترل وضعیت است. یکی از روشهای مؤثر تخمین این نوع از مدلهای دینامیکی، روش کمترین مربعات خطا در ترکیب با فیلتر کالمن است. برای افزایش عملکرد روش تخمین ذکر شده، الگوریتم آنلاین فرا ابتکاری جدیدی بر اساس توسعه روش کمترین باقیمانده تعمیمیافته ارائه میگردد. این الگوریتم یک روش مبتنی بر تکرار است که با استفاده از اطلاعات مرحله قبل و بر اساس تجربه کاربر، و یا یک روش فرا ابتکاری آنلاین نوین، تعداد گامهای حل دستگاه در زیر فضای کریلف را تعیین کرده و همگرایی کلی به پاسخ را بهبود میبخشد. برای بررسی دقت تخمین این روش، روشهای کمترین باقیمانده تعمیمیافته ساده، گرادیان دو مزدوجی، گرادیان مزدوج مربعی و گرادیان دو مزدوجی پایدار مقایسه شده است، که روش فرا ابتکاری کمترین باقیمانده تعمیمیافته تطبیقی بیشترین دقت و پایداری در پاسخ را نشان میدهد.
physiology and space medicine (astrobiology)
Narjes Rahmanian; Azadeh Hekmat; Zahra Hajebrahimi
Volume 15, Issue 2 , June 2022, , Pages 81-92
Abstract
Muscle atrophy is one of the problems that astronauts face after returning to earth. Myostatin is a known negative regulator of muscle growth. This study aimed to investigate the effects of simulated microgravity condition on mouse myotube cells (C2C12) growth and the myostatin gene expression. The morphological ...
Read More
Muscle atrophy is one of the problems that astronauts face after returning to earth. Myostatin is a known negative regulator of muscle growth. This study aimed to investigate the effects of simulated microgravity condition on mouse myotube cells (C2C12) growth and the myostatin gene expression. The morphological studies and MTT cytotoxicity assay showed no significant alternation in cells after 48h simulation microgravity, however, after 72h ~40% of cell death accrued (p<0.05). The AO/PI staining and DNA fragmentation analysis confirmed this observation too. Analysis of the gene expression revealed that simulated microgravity reduced myostatin gene expression significantly after 48h (p<0.0001), however, after 72h, increased significantly (P<0.001). So, inhibition of myostatin expression in differentiated myocyte cells of astronauts could be an effective procedure to reduce skeletal muscle atrophy under microgravity condition.
space sciences and exploration
Fateme Mousavi
Volume 16, Issue 4 , December 2023, , Pages 83-89
Abstract
Seed aging is a process that can lead to a complete loss of seed viability. This process occurs when seeds are exposed to long-term storage or controlled deterioration treatments such as excessive dryness, lack of oxygen, and temperature fluctuations on Earth or in outer space. Proteomic changes can ...
Read More
Seed aging is a process that can lead to a complete loss of seed viability. This process occurs when seeds are exposed to long-term storage or controlled deterioration treatments such as excessive dryness, lack of oxygen, and temperature fluctuations on Earth or in outer space. Proteomic changes can occur in the dry state of seeds. Extreme temperature fluctuations in outer space, especially on the moon and Mars, are one of the most important challenges for space scientists to transfer plant seeds and grow them in outer space outside the atmosphere. The present study studied the effects of simulated space temperature fluctuations on the quantitative and qualitative content of dry tomato seed proteins. The results showed 13 protein bands in the molecular weight range of 8.89 to 91.82 kilodaltons. A double or more significant decrease in the intensity of protein bands with high molecular weight was also observed in the treated group compared to the control. Finally, the two-dimensional electrophoresis technique followed by mass spectrometry is suggested for better resolution of tomato seed proteins and their better separation, as well as identification of unknown protein bands in future studies.
Space systems design (spacecraft, satellites, space stations and their equipment)
Mohammad Reza Salimi
Volume 15, Issue 1 , March 2022, , Pages 89-105
Abstract
In present study, a hydrazine based monopropellant thruster decomposition chamber is simulated numerically. The catalyst bed separated in two sides, the particles size in upstream side is larger than those in downstream side. Effects of upstream side length and its particles diameter on catalyst bed ...
Read More
In present study, a hydrazine based monopropellant thruster decomposition chamber is simulated numerically. The catalyst bed separated in two sides, the particles size in upstream side is larger than those in downstream side. Effects of upstream side length and its particles diameter on catalyst bed characteristics were investigated. To this end, three standard particles sizes of mesh: 16.5, 25 and 30 for the upstream side and two standard particles diameter of 1/8 and 1/16 (in) for downstream side were analyzed. Additionally, three upstream side lengths of 2.5, 5 and 7.5 (mm) were used while the length of bed is 6.5 (cm). Simulations were performed in three bed loading coefficients of 16.5, 25 and 35 (kg/m2s). The related results showed the effectiveness of upstream side on flow and thermal fields are strongly depends on the ration of particles sizes in upstream and downstream sides. Moreover, the upstream side length and bed loading are two important factors affecting the upstream side effectiveness.
physiology and space medicine (astrobiology)
Vajihe Zarrinpour; Zahrs Hajebrahimi
Volume 15, Issue 4 , December 2022, , Pages 89-96
Abstract
A study of the effect of microgravity on the endothelial progenitor cells is useful both in understanding cardiac changes in astronauts and in using microgravity as angiogenic stimuli. The aim of the present study was to investigate the effect of microgravity on VEGFR-2 and CD34 angiogenesis markers. ...
Read More
A study of the effect of microgravity on the endothelial progenitor cells is useful both in understanding cardiac changes in astronauts and in using microgravity as angiogenic stimuli. The aim of the present study was to investigate the effect of microgravity on VEGFR-2 and CD34 angiogenesis markers. Following extraction of progenitor cells from peripheral blood and its confirmation, gene expression was assessed by real-time PCR, and cell viability was assessed by MTT assay. The extracted cells were endothelial progenitor cells in terms of shape and surface markers CD31 and CD144. Microgravity increased the VEGFR-2 gene expression by 3.5 times after 24 hours. CD34 expression increased by 50% after 3 h but reached control level after 24 hours. Microgravity appears to have a positive effect on the expression of angiogenic markers and stimulation of endothelial progenitor cells, and it may be used as a new environment to differentiate these cells into blood vessels and to treat heart disease.
Space systems design (spacecraft, satellites, space stations and their equipment)
Sajjad Gharezi; Mohammad Mehdi Doustdar
Articles in Press, Accepted Manuscript, Available Online from 17 January 2024
Abstract
In this research, the design of a can combustion chamber for a ramjet engine, the performance of this chamber and the role of flameholder have been studied. For this purpose, after talking about ramjet engine types, some general information about the combustion chamber has been explained. Then the process ...
Read More
In this research, the design of a can combustion chamber for a ramjet engine, the performance of this chamber and the role of flameholder have been studied. For this purpose, after talking about ramjet engine types, some general information about the combustion chamber has been explained. Then the process of chamber designing and determining its geometry has been discussed. The dimensions of the chamber were determined by using input conditions extracted from GasTurb software as well as applying a calculation code, and the geometry of the chamber have been determined by applying calculation codes. By evaluating the obtained geometry and ensuring the accuracy of the design, simulation of combustion with non-premixed liquid phase was carried out using Fluent software. While presenting the results, the effects of size, distance and number of flameholder have been investigated. It is shown that the use of flameholder in ramjet engines is essential but the use of large flameholder is not recommended.
F. Sadeghikia; S. Amin; K. Raisi; M. Bahrami
Volume 1, Issue 2 , December 2008, , Pages 57-60
Abstract
This paper provides an instruction for designing and building of an Inverted F antenna mounted on a cylindrical conducting body with a conical nose. Designed antennas were simulated using a full wave simulator HFSS based on the finite element method and their radiation patterns and return loss were studied. ...
Read More
This paper provides an instruction for designing and building of an Inverted F antenna mounted on a cylindrical conducting body with a conical nose. Designed antennas were simulated using a full wave simulator HFSS based on the finite element method and their radiation patterns and return loss were studied. The simulated data were compared with measurement results.
E Peighani-Asl; D Abbasi-Moghadam; B Ghafary; V Tabataba-Vakili
Volume 2, Issue 3 , December 2009, , Pages 57-70
Abstract
Remote sensing using small spacecraft arising from multi-objective economic activity problems is getting more and more developed. These satellites require very accurate pointing to specific locations of interest, with high reliability and small latency. The space borne imaging systems always attempted ...
Read More
Remote sensing using small spacecraft arising from multi-objective economic activity problems is getting more and more developed. These satellites require very accurate pointing to specific locations of interest, with high reliability and small latency. The space borne imaging systems always attempted to achieve the highest ground resolution possible with the available technology at the given time. Also mass, volume and power consumption of the spacecrafts and instruments followed the trend to miniaturization. But the most promising prospects for high resolution imaging with remote sensing satellites are connected with passive optical systems, especially push broom systems. In this paper optical system design process is described and different parameters of this process such as MTF, SNR, FOV, aperture diameter, stability and pointing, scanning schemes, detector selection, and target radiance are simulated and analyzed.
V. Sedghi; M. Safavi Homami
Volume 6, Issue 4 , January 2014, , Pages 63-67
Abstract
Rapid growth in using Commercial of The Shelf (COTS) components in Space missions compelled the researchers to evaluate the performance of this components in space environment. AT90CAN128 commercial microcontroller is used in AutSat mission due to high performance, simple structure, low power consumption ...
Read More
Rapid growth in using Commercial of The Shelf (COTS) components in Space missions compelled the researchers to evaluate the performance of this components in space environment. AT90CAN128 commercial microcontroller is used in AutSat mission due to high performance, simple structure, low power consumption and the ability of CAN bus management. In this paper the result of Total Ionizing Dose test on this microcontroller is presented. These results confirm the possibility of using this microcontroller for our satellite with minimum 3 years life cycle.
M. Nosratolahi; V. Blochestani; A. H. Adami-Dehkordi
Volume 2, Issue 1 , April 2009, , Pages 67-71
Abstract
This article generates the algorithm for increasing performance of a space launch vehicle using solid rocket boosters.In all of the world, many space launch vehicles are designed with limited performance capabilities. But when the increased performance capabilities is required, one of the best solution ...
Read More
This article generates the algorithm for increasing performance of a space launch vehicle using solid rocket boosters.In all of the world, many space launch vehicles are designed with limited performance capabilities. But when the increased performance capabilities is required, one of the best solution that used on all of them, is using of solid rocket boosters. Solid rocket boosters has simple design and manufacturing capabilities and even converting the existing solid rocket booster blocks is one of the solutions.
MohammadReza Heidari; AmirHoseyn Adami
Volume 5, Issue 3 , October 2012, , Pages 67-80
Abstract
In this paper, specific grains burn back is presented by new geometrical method. The software is developed for Wagon wheel grains and 3D grains. Rapid solid motor ballistic simulation code produces required charts with considered nozzle geometry. Presented method used geometrical introducer point (GIP) ...
Read More
In this paper, specific grains burn back is presented by new geometrical method. The software is developed for Wagon wheel grains and 3D grains. Rapid solid motor ballistic simulation code produces required charts with considered nozzle geometry. Presented method used geometrical introducer point (GIP) to produce the various grains. Limitations and configurations are simply modeled. Thrust, total pressure and temperature are illustrated as web burned changing. The results confirm the performance of the developed algorithm for mentioned grain analysis. Lower time processing and rapid ballistic analysis are the benefits of the presented algorithm. Finally results of the burn back analysis code and the internal ballistic simulation code are evaluated by some other existent codes and real cylindrical grain test.
M. Fakoor; A. R. Kosari; H. Salehghaffari
Volume 6, Issue 2 , July 2013, , Pages 67-74
Abstract
This paper deals with the estimation of gyro model parameters and GEO satellite moment of inertia at the same time in transfer orbit phase. In order to fuse information of attitude determination subsystem sensors, an extended Kalman Filter has been employed. The estimation variables are including: quaternion, ...
Read More
This paper deals with the estimation of gyro model parameters and GEO satellite moment of inertia at the same time in transfer orbit phase. In order to fuse information of attitude determination subsystem sensors, an extended Kalman Filter has been employed. The estimation variables are including: quaternion, angular velocity, moments of inertia, and gyro sensor model parameters which are bias and scale factor vectors. The satellite motion equations along with gyro sensor and quaternion measurements have been used to design an Extended Kalman Filter in order to estimate the desired states. The disturbance torque effect on moment of inertia identification has been also considered. Estimation results via some case studies demonstrate the numerical simulation section exhibit robustness and efficiency of Kalman Fillter.
A. Aghaei; H. Sadeghi; H. Jahanbakhsh; R. Taheri; A. Mossavi; A.M. Niko
Volume 6, Issue 3 , October 2013, , Pages 67-73
Abstract
OSL dosimeter system was introduced first time in 1963 and it has been used for space application science 2005 by space organizations. In this work we try to design and fabricate this system in Iran for the first time .Basic physical quantum of this system is optically stimulated luminescence. This system ...
Read More
OSL dosimeter system was introduced first time in 1963 and it has been used for space application science 2005 by space organizations. In this work we try to design and fabricate this system in Iran for the first time .Basic physical quantum of this system is optically stimulated luminescence. This system consist of OSL material, Optical section for Stimulation and reader section. In this work, first the basic theory of OSL phenomena has been reviewed, then the space applications and the advantage of this system has been compared with other dosimeter system. Afterward laboratory construction of this system and some characterizations of that such as primary calibration by Co-60 source, has been introduced. Finally, results of evaluation of this system shows that,this fabricated system has linear response function in rang of 1-10 Gy.
M. Mortazavi; D. Abbasi-Moghadam
Volume 3, Issue 2 , January 2011, , Pages 69-76
Abstract
هدف اصلی مقاله حاضر، هدایت بهینه و برخط اجسام بازگشتی به زمین است. روند دستیابی به این مهم مبتنی بر روش بسط مجانبی هماهنگ است که یکی از روشهای خانوادة اغتشاشات تکین است ...
Read More
هدف اصلی مقاله حاضر، هدایت بهینه و برخط اجسام بازگشتی به زمین است. روند دستیابی به این مهم مبتنی بر روش بسط مجانبی هماهنگ است که یکی از روشهای خانوادة اغتشاشات تکین است و به کمک روش تغییر اکسترمالها تقویت شده است. روش جدید حاصل MAEOGکه مخفف کلمات مربوط به هدایت بهینة مبتنی بر بسط مجانبی هماهنگ است ضمن ارائة راه حل با دقت قابل قیاس با روشهای دیگر، بسیار سریع مسئله را به جواب میرساند و زمان حل را کاهش میدهد. به علاوه، این امکان را میدهد که چه برا و چه زاویة رول به عنوان متغیرهای کنترل در نظر گرفته شوند. ویژگیهای روش جدید برای توسعة الگوریتم هدایتی بازگشت به زمین کاملاً مناسب به نظر میرسند.
Amir Hosein Tavakkoli; Masoud Yazdanian; Yarollah Koolivand; Morteza Shahravi; Morad Momeni; S. Mohammad Mahdi Dehghan
Volume 5, Issue 4 , January 2013, , Pages 69-78
Abstract
Evaluation of the satellite attitude determination system is very complicate because of need to simulate space environment on the ground. In this paper a laboratory Implementation of attitude estimation using sun sensor and magnetometer is reported. The test setup includes a sun simulator installed in ...
Read More
Evaluation of the satellite attitude determination system is very complicate because of need to simulate space environment on the ground. In this paper a laboratory Implementation of attitude estimation using sun sensor and magnetometer is reported. The test setup includes a sun simulator installed in a dark room. The magnetometer measures the local magnetic field. Sensors are rotated using a 2 DOF table. The reference models are adapted with the test setup. Attitude determination using classic and extended kalman filter methods is implemented by sensors data fusion. The test results verify the controlled motion of sensors in the limits of setup accuracy order.
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 ...
Read More
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.
R Zardashti; M Bagherian
Volume 2, Issue 2 , July 2009, , Pages 75-79
Abstract
In this paper a new guidance technique for ballistic missiles and launch vehicles is proposed. Generally the Lambert guidance is used to generate missile nominal (correlated) parameters through powered flight to put it in a ballistic flight path. Because of uncertainties and undesired factors, the nominal ...
Read More
In this paper a new guidance technique for ballistic missiles and launch vehicles is proposed. Generally the Lambert guidance is used to generate missile nominal (correlated) parameters through powered flight to put it in a ballistic flight path. Because of uncertainties and undesired factors, the nominal position and velocity obtained by Lambert technique need to be followed in actual flight. In this paper the Flight Path angle Steering (FPS) procedure is used to accomplish the tracking of nominal parameters. The numerical simulations indicate that the integrated procedure is a cost-effective and suitable scheme for guiding ballistic missiles and launch vehicles especially in design process. In spite of the simplifications made in FPS procedure, numerical simulations show that there is very little difference between the results obtained by FPS and the results obtained by Q-guidance method.
M. Jafari Nadoushan; S. H. Pourtakdoust
Volume 3, Issue 1 , July 2010, , Pages 75-80
Abstract
Development of halo orbits and their associated invariant manifolds are investigated. Halo orbits play a fundamental role in complex space mission designs. In essence, halo orbits are periodic solutions of the restricted three body problem (R3BP) determined under specific initial conditions. In this ...
Read More
Development of halo orbits and their associated invariant manifolds are investigated. Halo orbits play a fundamental role in complex space mission designs. In essence, halo orbits are periodic solutions of the restricted three body problem (R3BP) determined under specific initial conditions. In this paper, the symmetric property of the nonlinear R3BP governing differential equations is utilized in order to obtain the desired initial conditions. In this regard the differential correction technique and the state transition matrix are used to generate the halo orbits. The differential correction technique, based on the Newton method, is an effective tool for solving two point boundary value problems. In addition to generate the stable and unstable manifolds, the initial conditions are perturbed in the direction of Eigenvectors and the equations of motion are integrated for an arbitrary time interval.
H. Mahdavy Moghaddam; M. M. Javadi
Volume 5, Issue 2 , July 2012, , Pages 75-83
Abstract
Outer space ballistic missiles use thrust vector control system and it is because aerodynamic surfaces are not efficient in thin air.Flexible joint is the most useful type of thrust vector control system through satellite transporters and ballistic missiles based on solid fuel. Most common type of elastomer ...
Read More
Outer space ballistic missiles use thrust vector control system and it is because aerodynamic surfaces are not efficient in thin air.Flexible joint is the most useful type of thrust vector control system through satellite transporters and ballistic missiles based on solid fuel. Most common type of elastomer in these structures is rubbers and especially natural rubber, which require special preparation and cure processes. The goal defined in this article is to introduce a process which is much easier to apply. Based on flexible joint design in Japanese MV booster missile, an elastomer based on polyurethane resin, which is easily applicable and consists of two liquid parts, is used instead of original Polyisoperne. This elastomer has achieved a good rank in both sealing test in eight-bar pressure and hydrostatic test in the pressure of 70 bars. It also has been fire tested and the results were satisfactory.
M. Sohrab; R. Zardashti; S. H. Jalali-Naini
Volume 7, Issue 3 , October 2014, , Pages 75-82
Abstract
In this paper, a fuzzy logic guidance algorithm is presented for the ascending phase of satellite launch vehicles in the presence of wind effects. In this algorithm, the midcourse constraints including maximum allowable angle of attack at the maximum dynamic pressure and the product of the dynamic pressure ...
Read More
In this paper, a fuzzy logic guidance algorithm is presented for the ascending phase of satellite launch vehicles in the presence of wind effects. In this algorithm, the midcourse constraints including maximum allowable angle of attack at the maximum dynamic pressure and the product of the dynamic pressure and angle of attack, as well as constraints on the final altitude and flight-path angle are considered. The algorithm uses a Mamdani-type fuzzy controller with centroid defuzzification.Maximizing and minimizing set methods to reduce wind effect, while satisfying the midcourse and final constraints. Simulation results show that the presented algorithm improves the performance of the satellite launch vehicle, satisfying the constraints within the maximum allowable estimation error on wind speed.
Space subsystems design: (navigation, control, structure and…)
Mohammad Chiniforoushan; Mahdi Mortazavi; kamran raissi
Volume 14, Issue 1 , March 2021, , Pages 77-92
Abstract
The problem of jointly controlling relative attitude and position of spacecraft in the presence of actuator fault is investigated in this paper. Following a description about drawbacks and limitations of the existing models and the control approaches based on them, a new formulation of the spacecraft ...
Read More
The problem of jointly controlling relative attitude and position of spacecraft in the presence of actuator fault is investigated in this paper. Following a description about drawbacks and limitations of the existing models and the control approaches based on them, a new formulation of the spacecraft relative motion is provided. Subsequently, the subspace predictive control framework, which is a powerful model-free approach, is extended in several dimensions, that is, adaptive nonlinear control, tolerance against abrupt faults and control allocation. Based on this generalized framework, three distinct data-driven fault-tolerant controllers for coupled, nonlinear and time-variant plants are developed. From the viewpoint of fault diagnosis, the only requirement of the control structure is to detect the occurrence time of faults. Furthermore, an internal data-driven fault diagnosis capability is introduced, which makes the control structure completely self-sufficient. The three controllers are then designed to solve the aforementioned problem, and their efficiency are verified via a multidimensional simulation scenario.
