Space systems design (spacecraft, satellites, space stations and their equipment)
Hojat Taei; Mahmood Haghighat Esfahani; Sajjad Yadegari Dehkordi
Volume 14, Issue 3 , September 2021, , Pages 39-50
Abstract
In this paper, a novel Comprehensive Preference-based Design (CPD) approach is presented which attempts to achieve subjective attributes that are defined in the concept of maximization of designer/customer's satisfaction in addition to objective goals which are formulated in the form of minimization ...
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In this paper, a novel Comprehensive Preference-based Design (CPD) approach is presented which attempts to achieve subjective attributes that are defined in the concept of maximization of designer/customer's satisfaction in addition to objective goals which are formulated in the form of minimization of a performance criterion in a two-phase structure using two nested optimizers.In the first phase of CPD,using the concept of satisfaction,the subjective preferences of the designer/customer are defined in terms of fuzzy relationships and operators.Whereas the results of this phase are inaccurate,in the second phase,it is attempted to define a performance criterion and in order to achieve an optimal operational plan,attitude parameters and the compromises needed to meet the designer/customer's preferences are implemented.The methodology is utilized to design of a space launch vehicle for delivering 1200 kg payload to a 750 km orbit.Comparison of the results shows that despite the higher mass of launch vehicle designed by CPD,overall design satisfaction is higher and designer/customer's preferences have been satisfied.
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.
Seyed Mohammad Reza Mosavi; Narjes Rahemi; Satar Mirza Kuchaki
Volume 7, Issue 4 , January 2015, , Pages 63-72
Abstract
GPS is a satellite-based navigation system that is able to determine the exact position of objects on the Earth, sky, or space. By increasing the velocity of a moving object, the accuracy of positioning decreases; meanwhile, the calculation of the exact position in the movement by high velocities like ...
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GPS is a satellite-based navigation system that is able to determine the exact position of objects on the Earth, sky, or space. By increasing the velocity of a moving object, the accuracy of positioning decreases; meanwhile, the calculation of the exact position in the movement by high velocities like airplane movement or very high velocities like satellite movement is so important. In this paper, two methods for positioning in very high velocities based on recursive least squares method and its combination with fuzzy logic are presented. Simulations on different data with different velocities show that proposed method can improve the accuracy of positioning more than 50%. In previous methods, the algorithm is quite dependent on the initial point, whereas in proposed method, this dependency is resolved.
