Hossein Darabi; Jafar Roshanian
Volume 8, Issue 2 , July 2015, , Pages 27-39
Abstract
Collaborative optimization is one of bi-level multidisciplinary optimization methods which consists of system level and discipline level and is applied for complex engineering problems. since this method is rigidly convergent at discipline level because of noisy constraints at system level on one hand ...
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Collaborative optimization is one of bi-level multidisciplinary optimization methods which consists of system level and discipline level and is applied for complex engineering problems. since this method is rigidly convergent at discipline level because of noisy constraints at system level on one hand and minimizing objective function necessity at system level on the other hand, this optimizationmethod is forced to use evolutionary algorithms in order to minimize objective function at system level, also, It has been proved that, applying this algorithms according to their nature is expensive and time consuming. This paper with performed inspections is a new method for applying innovated optimization algorithms through which considerable results are obtained in solving sample problems. It is shown that using this method will decrease function calls number or problem solving time and therefore calculating costs will decrease considerably. Also it is shown that this method sometimes increase accuracy.
Seyed Hossein Torabi; Jafar Roshanian; Hamid Arabshahi
Volume 8, Issue 2 , July 2015, , Pages 67-78
Abstract
In this Paper, The online optimal integrated guidance and control algorithm design has been provided for two-stages Launch Vehicle .The flight equations are nonlinear and has been derived in flight plane. In order to solve it based on numerical solution and shooting method logic by the combination between ...
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In this Paper, The online optimal integrated guidance and control algorithm design has been provided for two-stages Launch Vehicle .The flight equations are nonlinear and has been derived in flight plane. In order to solve it based on numerical solution and shooting method logic by the combination between ODE - start to end solver algorithm by considering initial conditions for integrated states and co-states - and optimization fmincon SQP algorithm has been acted. In order to verify designing method the results of this algorithm solutions has been compared with the results of a valid separated guidance and control algorithm for launch vehicle. The result function involves minimum control effort, terminal terms and minimizing burning time. The results indicate the satisfaction of three mentioned identities achieving high accurate orbital insertion and more coordination between the operation of guidance and control algorithms in integrated logic comparing with separated ones.
A. R. Alemi Naeeni; J. Roshanian
Volume 6, Issue 4 , January 2014, , Pages 53-62
Abstract
In this paper, a multi-objective guidance scenario has been developed which could be used to improve the accuracy of sub-orbital modules at the entry to the earth’s atmosphere. Developed algorithm could be used for the trajectory shaping and adjusting of the trajectory relative to the desired position. ...
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In this paper, a multi-objective guidance scenario has been developed which could be used to improve the accuracy of sub-orbital modules at the entry to the earth’s atmosphere. Developed algorithm could be used for the trajectory shaping and adjusting of the trajectory relative to the desired position. To achieve defined objectives, it has been organized in three phases relative to different layers of trajectory. In the first phase, using of sensitivity functions which are of less computational burden, improving the accuracy according to the reference trajectory is done. In the second phase, trajectory shaping which is required to achieve desired flight performance is applied which could be designed and performed online in the mission. Finally in the last phase which is relative to low altitudes, improving of the accuracy according to homing rules is performed. Validation of developed algorithm using of a sample guidance problem is presented finally.
A. R. Alemi Naeeni; J. Roshanian
Volume 6, Issue 3 , October 2013, , Pages 15-26
Abstract
This paper presents an explicit guidance method which could be used in the problems of orbit correction for sub-orbital modules. This method is based on solving the Lambert problem. Two efficient methods of solving the Lambert problem are introduced and compared. Using of the selected method a guidance ...
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This paper presents an explicit guidance method which could be used in the problems of orbit correction for sub-orbital modules. This method is based on solving the Lambert problem. Two efficient methods of solving the Lambert problem are introduced and compared. Using of the selected method a guidance scenario is developed which is capable of solving the problem under investigation. All of the methods of solving the Lambert problem, are based on spherical gravitational field and aerodynamic forces are not considered by them. In order to consider those important factors, a method is presented which increases the accuracy of guidance block computations. Finally using of developed method, two sample problems are investigated. Applying the developed method, a guidance block is prepared which performs the required maneuvers in a mission. Monte Carlo simulation confirms the ability of developed method in different conditions.
J. Roshanian; S. M. M. Hassani; M. M. Nazari; M. Aliyari
Volume 6, Issue 2 , July 2013, , Pages 49-56
Abstract
Aerospace Launch Vehicles (ALV) are generally designed with high reliability to operate in complete security through fault avoidance practices. However, in spite of fault avoidance, fault occurring is inevitable. Hence there is a requirement for on-board fault detection and isolation (FDI) without significant ...
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Aerospace Launch Vehicles (ALV) are generally designed with high reliability to operate in complete security through fault avoidance practices. However, in spite of fault avoidance, fault occurring is inevitable. Hence there is a requirement for on-board fault detection and isolation (FDI) without significant degradation in the ALV performance. The robust observers are widely used in FDI due to reduction of the effect of disturbances in the FDI process. In this paper, the robust fault diagnosis observer is designed for an ALV subject to uncertainties. The linear sliding mode technique is used to design the observer for a linear time varying model of an ALV. The parameter estimation from the sliding mode scheme is compared with those generated by a nonlinear simulation and are found to provide good correlation. Then, a proposed linear sliding mode observer is employed to generate the residual as an indicator of predefined gyroscope faults.
M. Jafari; M. Taefi; J. Roshanian
Volume 6, Issue 2 , July 2013, , Pages 57-66
Abstract
Flight dynamic equations have an effective role in aerospace technologies. It can be as cheap and efficient means for correcting errors in the spatial position and velocity in inertial navigation systems. The Inertial navigation system is an ideal solution for motion detection with high accuracy with ...
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Flight dynamic equations have an effective role in aerospace technologies. It can be as cheap and efficient means for correcting errors in the spatial position and velocity in inertial navigation systems. The Inertial navigation system is an ideal solution for motion detection with high accuracy with fast dynamics, but the precise location and status of the system output can be significantly reduced over time. In this paper, inertial navigation system integrated with a navigation aided system based on online solving of flight dynamic equations. For this purpose, the proposed use of the Lagrangian of Kepler equations and three degrees of freedom of Newton's equations of transfer flights dynamic has been studied. Using this method, online high accuracy to be achieved by flight computer. Kalman filter algorithm is used for integrating inertial navigation and flight dynamic equations . Finally, The simulation results including position and velocity errors with regard to fly a prototype space module, for the proposed two conditions were compared and the advantages and disadvantages of each method are presented
F. Moosavi; J. Roshanian; R. Emami
Volume 6, Issue 1 , April 2013, , Pages 1-10
Abstract
This paper presents the control design for large angle and high rotation rates maneuvers using reaction cold gas thrusters. Navigation system provides suborbital attitude changes in terms of quaternion. Cold gas thrusters with pulse-width pulse-frequency modulation provide nearly proportional control ...
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This paper presents the control design for large angle and high rotation rates maneuvers using reaction cold gas thrusters. Navigation system provides suborbital attitude changes in terms of quaternion. Cold gas thrusters with pulse-width pulse-frequency modulation provide nearly proportional control torques. The use of quaternion as attitude errors for large angle feedback control in a suborbital capsule is investigated. Numerical simulations demonstrate the practical feasibility of a three-axis large angle maneuver.
Jafar Roshanian; Mehdi Hassani; Shabnam Yazdan; Masoud Ebrahimi
Volume 5, Issue 4 , January 2013, , Pages 1-8
Abstract
Star tracker is an attitude determination device which determines the satellite or spacecraft’s attitude using the star position information in inertial and body references. Star information is collected and stored onboard as a “Star or mission catalog”. There are several star catalogs ...
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Star tracker is an attitude determination device which determines the satellite or spacecraft’s attitude using the star position information in inertial and body references. Star information is collected and stored onboard as a “Star or mission catalog”. There are several star catalogs that contain different kinds of information with different accuracy. In this paper the most used star catalogs are introduced and a few star catalog selection features are recommended. These features are weighted according to the star tracker mission type. For the selected star tracker mission, results demonstrate that Hipparcos star catalog is the best choice. Eventually using Hipparcos star catalog, a mission catalog is developed to be used onboard a typical star tracker.
Mahdi Jafari; Arash Sangary; Jafar Roshanyan
Volume 5, Issue 3 , October 2012, , Pages 11-19
Abstract
The Inertial navigation system is an ideal solution for motion detection with high accuracy with fast dynamics, but the precise location and status of the system output can be significantly reduced over time. On the other hand, global positioning system is able to determine its position with an average ...
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The Inertial navigation system is an ideal solution for motion detection with high accuracy with fast dynamics, but the precise location and status of the system output can be significantly reduced over time. On the other hand, global positioning system is able to determine its position with an average accuracy around the earth. But the GPS alone isn’t enough for navigation of orbital modules, because it doesn’t have situation of orbital modules. The integrated inertial navigation system with global positioning system is a low cost method of providing an accurate and reliable navigation system in the civilian and military aerospace applications. In this paper, using the extended Kalman filter, we design an algorithm to estimate error of sensors, navigation and GPS. This method can be widely used in the integrated navigation INS / GPS in aerospace applications and provides an accurate navigation.
S. M. Hashemi Doulabi; H. Darabi; J. Roshnian
Volume 5, Issue 1 , April 2012, , Pages 61-72
Abstract
One of the most important problems that nowadays are common in aerospace societies in Iran and also around the world is how to optimize the designing of the flight objects. Since the flight objects like LVs, which are the subject of this paper, are composed of several subsystems that have influences ...
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One of the most important problems that nowadays are common in aerospace societies in Iran and also around the world is how to optimize the designing of the flight objects. Since the flight objects like LVs, which are the subject of this paper, are composed of several subsystems that have influences to each others, the multidisciplinary design optimization methods(MDO) are commonly used for doing design optimization of them. In usage of the multidisciplinary design optimization methods for different objects, to select the proper optimization algorithm is one of the very important problems. In this research the conceptual design of a lightweight liquid propellant LV is done with the all at once (AAO) method. The object of optimization is to minimize gross launch weight and four disciplines of structure, aerodynamics, trajectory, and propulsion are considered. Performance of gradient based algorithm of SQP and heuristic algorithm of GA and traditional method (statistical method) by solving an example are compared and is shown that if the output of statistical method is used as start point of optimization using gradient based algorithm of SQP, the global answer will be derived.
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. Sayanjali; J. Roshanian; A. Ghafari
Volume 2, Issue 1 , April 2009, , Pages 43-50
Abstract
In this paper, equation of motion of three axis attitude dynamic of flexible spacecraft is derived using combination of finite element method and Euler equation. Flexible appendafes are modeled by beam elements. Goal of control is target attitude of spacecraft from initial state to desired attitude and ...
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In this paper, equation of motion of three axis attitude dynamic of flexible spacecraft is derived using combination of finite element method and Euler equation. Flexible appendafes are modeled by beam elements. Goal of control is target attitude of spacecraft from initial state to desired attitude and suppression of vibration that induced in flexible appendages. So a combination of backstepping and sliding mode control method used for three-axis attitude maneuver of flexible spacecraft and for suppressing vibration of flexible appendage used from active vibration control method by PZT actuator. Control law for vibration control is based on LQG method
