Space systems design (spacecraft, satellites, space stations and their equipment)
Hojat Taei; Amirhossain Adami; Mansour Hozuri
Volume 14, Issue 4 , December 2021, , Pages 85-98
Abstract
The need to improve the reliability and safety requirements, has led to increasingly utilization of reliability based design approaches. In this study, reliability based multidisciplinary design optimization for a bipropellant propulsion system has been investigated. The objective function is minimizing ...
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The need to improve the reliability and safety requirements, has led to increasingly utilization of reliability based design approaches. In this study, reliability based multidisciplinary design optimization for a bipropellant propulsion system has been investigated. The objective function is minimizing the total system mass and design constraints are the total impulse and the temperature of the wall of the combustion chamber. Monte Carlo simulation methodology is used to apply uncertainties in the problem and to show the reliability of the system under these uncertainties. The mass, functional and geometric results of the bipropellant propulsion system are differentiated for optimal design, reliability based design and optimal reliability based design. Then, considering the results, the concepts and definitions of design methods are compared and discussed and it is shown that the reliability based multidisciplinary optimization while having the desired mass, has high reliability.
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.
Space systems design (spacecraft, satellites, space stations and their equipment)
Hojat Taei; Pourya Shokrolahi
Volume 13, Issue 2 , June 2020, , Pages 87-96
Abstract
The final phase of orbital rendezvous and docking has been studied in this article. The main objective is to control the position of a chaser that can reach the target in the minimum time, or in other words, bypassing the optimal path. Another important objective of this paper is the minimum energy consumption. ...
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The final phase of orbital rendezvous and docking has been studied in this article. The main objective is to control the position of a chaser that can reach the target in the minimum time, or in other words, bypassing the optimal path. Another important objective of this paper is the minimum energy consumption. In the dynamic simulation, the equations of the linear form of Clohessy-Wiltshire (CWH) equations have been utilized. In linear CWH equations, the change in either direction of X or Y will result in the change in another direction and will affect the orbital docking operation. In order to achieve the objectives of this paper, the design variables should be optimized; To optimize the design variables, two methods, i.e. genetic algorithm (GA) and particle swarm optimization (PSO), have been used. Finally, to evaluate the real conditions, the results will be investigated by applying uncertainty in the outputs of thrusters.
Amirhossain Adami; Hojat Taei; Mansour Hozuri
Volume 12, Issue 1 , April 2019, , Pages 41-53
Abstract
Considering the importance of the presence of uncertainties in the design of complex engineering systems, in this research multidisciplinary design optimization process for a bipropellant propulsion system in the presence of uncertainties, which in addition to minimizing the system mass, has a high robust. ...
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Considering the importance of the presence of uncertainties in the design of complex engineering systems, in this research multidisciplinary design optimization process for a bipropellant propulsion system in the presence of uncertainties, which in addition to minimizing the system mass, has a high robust. Based on this, the multidisciplinary design view of the bipropellant propulsion system is expressed in both optimum design and optimum robust design. The continued with the application of uncertainties, the mass, operational and geometric results of the propulsion system are expressed in terms of optimum design, robust design and optimum robust design. According to the results, it is shown that the lowest mass occurs in optimum design mode. But with uncertainties, it is observed at this point that it has the least robust and reliability. It also attempts to explain the difference between the concepts of robust design and optimum design with the help of results
Hojat Taei; Mansour Hozuri; Amirhossain Adami
Volume 10, Issue 2 , September 2017, , Pages 53-63
Abstract
The hydrazine propulsion system is one of the most widely used monopropellantpropulsion systems. This low-cost and low mass system is used for the attitude control ofsatellites due to its high specificity and rapid response.For this purpose, in the presentstudy, an optimal design of a hydrazine monopropellant ...
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The hydrazine propulsion system is one of the most widely used monopropellantpropulsion systems. This low-cost and low mass system is used for the attitude control ofsatellites due to its high specificity and rapid response.For this purpose, in the presentstudy, an optimal design of a hydrazine monopropellant propulsion system with the aim ofminimization of total mass and maximization of total impulse in the framework ofmultidisciplinary design optimization and sequential design method is considered. Inaddition, the principles of multidisciplinary and sequential design are described in thispaper. It has been tried to examine the impact of different elements on design goals andcompare the optimal value obtained in each of the design structures from differentaspects. It should be noted that the design process is accomplished in two ways, i.e.single-objective and multi-objective, and the optimal multidisciplinary design method iscompared with the sequential design method for the hydrazine monopropellant propulsionsystem.
Hojat Taei; M. Mirshams; M. Ghobadi; M. A. Vahid D.; H. Haghi
Volume 8, Issue 4 , January 2016, , Pages 35-44
Abstract
This article describes the details of a Tri-axial Spacecraft Simulator Testbed (TSST) that has been developed as part of a research program on spacecraft multi-body rotational dynamics and control in Space Research Laboratory (SRL) at K. N. Toosi University of Technology. This dumbbell style simulator ...
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This article describes the details of a Tri-axial Spacecraft Simulator Testbed (TSST) that has been developed as part of a research program on spacecraft multi-body rotational dynamics and control in Space Research Laboratory (SRL) at K. N. Toosi University of Technology. This dumbbell style simulator includes a variety of components: spherical air-bearing, inertial measurement unit (IMU), rechargeable battery, reaction wheels (RW), on-board computer (OBC) and balancing masses. In this paper, an attitude control problem for the spacecraft simulator actuated by three reaction wheels is studied. Under the assumption of uniform gravity and frictionless air-bearing environment, reaction wheels generate control moments about the roll, pitch and yaw axes of the base body. The control objective is to perform attitude commands sent from users with the least power consumption and a high precision. To handle the non-linear model, a Linear Quadratic Ricatti (LQR) controller has been programmed and it efficaciously controlled the computer-modeled simulator for any given slewing maneuver. This control approach has been developed to facilitate the system to accomplish large-angle, three-axis slewing maneuvers using RWs as effective actuators.
