Research Paper
Space systems design (spacecraft, satellites, space stations and their equipment)
Hamed Hashemi Mehneh; amirreza Ghedamini Harouni
Volume 12, Issue 4 , December 2019, Pages 1-17
Abstract
The robust multi-disciplinary, multi-objective shape optimization of re-entry capsule with aero-thermodynamic, trajectory, stability and the geometry considerations are presented in this paper. In this research, the results of maximizing the volumetric efficiency of the capsules while minimizing the ...
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The robust multi-disciplinary, multi-objective shape optimization of re-entry capsule with aero-thermodynamic, trajectory, stability and the geometry considerations are presented in this paper. In this research, the results of maximizing the volumetric efficiency of the capsules while minimizing the ballistic coefficient and the longitudinal stability derivative with considering uncertainties are discussed in presence of some constraints on geometry, heating load, and load factor. To reduce the time and cost of robust optimization, the Adaptive Monte Carlo Simulation technique is used which decreases the number of required evaluations within the robust optimization process. Utilizing the constrained multi-objective genetic algorithm will result in a collection of robust optimal solutions. The results show that the performance of obtained robust optimal configurations is in a way that the considered constraints aren’t violated with 99.8% of confidence level even in the presence of uncertainties.
Research Paper
Javad Shams; Jafar Roshanian
Volume 12, Issue 4 , December 2019, Pages 19-33
Abstract
In this paper, the hybrid control of the formation flying of spacecrafts has been investigated. The trajectory deflection of space asteroids, which are potentially life-threatening on Earth, are being actively pursued in recent scientific researches. To accomplish this mission, several methods have been ...
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In this paper, the hybrid control of the formation flying of spacecrafts has been investigated. The trajectory deflection of space asteroids, which are potentially life-threatening on Earth, are being actively pursued in recent scientific researches. To accomplish this mission, several methods have been proposed to date, in which case the use of gravity tractor is an indicator and hence the method is used in this paper. The formation flight of spacecrafts technology is a function of the relative dynamic equations, which are also used for its active control. In this way, the PID controller, which is widely used in various industries and inherently has robust properties, has been used as a base controller, and the fuzzy control has been used to improve its adjustment, which results in the results obtained. From simulation, the performance of the combined controller performance is effective.
Research Paper
Space Engineering
Mohammad N. Meibody; Hassan Naseh; Fathollah Ommi
Volume 12, Issue 4 , December 2019, Pages 35-46
Abstract
Now, the required samples to achieve the specific precision of sensitivity analysis in design are performed based on trial and error methods. The purpose of this paper is to develop an approach for determining the number of the required sample to achieve the specific precision of sensitivity analysis. ...
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Now, the required samples to achieve the specific precision of sensitivity analysis in design are performed based on trial and error methods. The purpose of this paper is to develop an approach for determining the number of the required sample to achieve the specific precision of sensitivity analysis. Thus, in this paper, a new sensitivity analysis method is proposed based on the Progressive Latin hypercube Sampling (PLHS) and the convergence of the analysis results. For this purpose, a PLHS method has been developed. This cystic approach has led to a sensitivity analysis of accuracy, efficiency, and speed in a variety of models with a large number of large parameters and large changes. Sensitivity analysis has been performed on the design of a hydrazine monopropellant thruster catalyst bed model as a case study. The results of this study indicate that in the sensitivity analysis based on the PLHS, the minimum population required for sensitivity analysis with specified accuracy can be determined. This leads to lower processing costs in the sensitivity analysis process, especially in complex models.
Research Paper
GPS and navigation GPS)، GLONASS، GALILEO
Mojtaba Behzad Fallahpour; Hamid Dehghani; Ali Jabbar Rashidi; Abbas Sheikhi
Volume 12, Issue 4 , December 2019, Pages 47-56
Abstract
Reflectors are a very important tools in counteracting the space borne or airborne SAR imaging systems. Because they can be used in the form of decoy and camouflage protection designs due to their high level RCS. The remarkable thing on this mission is that the SAR radar is capable of sending the wave ...
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Reflectors are a very important tools in counteracting the space borne or airborne SAR imaging systems. Because they can be used in the form of decoy and camouflage protection designs due to their high level RCS. The remarkable thing on this mission is that the SAR radar is capable of sending the wave to earth in any direction, with any incident angle and in any frequency band, and capturing sensitive areas. The design of such an all-directional, multi-band reflector, and wide angles reflector is very complicated because the reflex function depends on various parameters such as the dimensions, shape and material of the reflector, the frequency, the incident angle, and the polarization of the radiated wave. Existing refractors generally have a high RCS in a particular direction at a specific frequency and at a narrow viewing angle. In this paper, we will attempt to design a refractor of all directions, multiple bands and wide angles using shape structures.
Research Paper
Space systems design (spacecraft, satellites, space stations and their equipment)
Vahid Bohlouri; Hossein Haghighi; Soheil Seyedzamani
Volume 12, Issue 4 , December 2019, Pages 57-67
Abstract
In this paper, damping mode of a satellite attitude control is designed and implemented using magnetic actuators in software /hardware-in-the-loop testbed. To this end, the equivalent of Earth’s magnetic field is designed using Helmholtz coil, frictionless is made by air-bearing, and algorithms ...
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In this paper, damping mode of a satellite attitude control is designed and implemented using magnetic actuators in software /hardware-in-the-loop testbed. To this end, the equivalent of Earth’s magnetic field is designed using Helmholtz coil, frictionless is made by air-bearing, and algorithms are developed on designed control board. By measuring the Earth’s magnetic field, actuator commands are generated by the damping algorithm then braking torque is produced. Some applied restrictions and special requirements such as non-simultaneous operation between magnetic sensor and magnetic actuators, air-bearing friction, initial angular velocity are considered. By identifying the air-bearing frictional model, the results are compared in software/hardware-in-the-loop. The compared results show that the ability of the designed system to perform damping mode.
Research Paper
Morteza Tayefi; Ghasem Kahe; Mijtaba Mehrafrooz
Volume 12, Issue 4 , December 2019, Pages 69-77
Abstract
Sounding rockets provide a useful platform for the aerospace research activities in which carry out a research payload to the space and recover it in the ground. In the flight path, it does scientific experiments and acquire the result for more analysis in the ground. All of the well-known aerospace ...
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Sounding rockets provide a useful platform for the aerospace research activities in which carry out a research payload to the space and recover it in the ground. In the flight path, it does scientific experiments and acquire the result for more analysis in the ground. All of the well-known aerospace centers around the world use frequently the various forms of sounding rocket to test and evaluate their sensitive space components. Actually, space qualification process of a space module is completed sometimes through a real space flight using the sounding rocket. In this paper the performance of a MEMS based inertial measurement unit (IMU) is investigated. The investigation result shows that using appropriate filtering, MEMS based IMU can measure appropriately the dynamic behavior of the sounding rocket. These data may be used for further identification and validation tests.
Research Paper
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. ...
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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.
Research Paper
recognition, evaluation, and detection of space radiation
Marjan Moghanipoor; Maryam Kiani; S. Hossein Pourtakdost; Amir Labibian
Volume 12, Issue 4 , December 2019, Pages 91-102
Abstract
Temperature sensors have recently been proposed for attitude estimation (AE) of Low-Earth satellites. However, since half of the satellite surfaces do not receive any heat flux from the Sun, conduction occurs among the satellite surfaces. In this regard, the present study has focused on the effect of ...
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Temperature sensors have recently been proposed for attitude estimation (AE) of Low-Earth satellites. However, since half of the satellite surfaces do not receive any heat flux from the Sun, conduction occurs among the satellite surfaces. In this regard, the present study has focused on the effect of surfaces’ conduction as well as inner radiation on AE using temperature sensors. The nonlinear filter of Unsceted Kalman filter is adopted for AE, and the developed model to describe temperature rates is verified using Thermal Desktop and SINDA software. Monte Carlo simulations prove positive effect of the conduction on AE performance against negative role of the inner radiation.