Hasan Naseh; Mehran Mirshams; Javad Naderifar
Volume 9, Issue 3 , December 2016, , Pages 73-79
Abstract
The main goal of this paper is development of multi-stage Launch Vehicle (LV) system design software based on advanced classical method. This software has been named Launch Vehicle Conceptual Classical Design (LVCCD). This software covers the complete syllabuses of LV System Design (LVSD) course. The ...
Read More
The main goal of this paper is development of multi-stage Launch Vehicle (LV) system design software based on advanced classical method. This software has been named Launch Vehicle Conceptual Classical Design (LVCCD). This software covers the complete syllabuses of LV System Design (LVSD) course. The main characteristic of the software development is to step by step training the LVSD. Also it can help the better understand in the course in the best quality and lower time. The algorithm used in the software developed according to the outline of LVSD (major design parameters, LV's mass-energy equations and velocity losses and etc.) and using the multi-stage LV statistical data. Hence, these advantages led to better understanding and conceive. Also LVCCD can improve the qualification of training. Finally, the LVCCD software evaluated and verified with the design software as Launch Vehicle Conceptual Design (LVCD) and PBRM by using existing multi-stage LV.
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.
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 ...
Read More
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. Mirshams; S. Irani; A. M. Akhlaghi; H. Naseh
Volume 5, Issue 2 , July 2012, , Pages 49-57
Abstract
The goal of this paper is presenting a methodology for reliability allocation to launch vehicle subsystems using Analytical Hierarchy Process (AHP) method in conceptual design phase. In this methodology, the goal function is reliability and the main considered criterions are technology, complexity, operational ...
Read More
The goal of this paper is presenting a methodology for reliability allocation to launch vehicle subsystems using Analytical Hierarchy Process (AHP) method in conceptual design phase. In this methodology, the goal function is reliability and the main considered criterions are technology, complexity, operational time of each subsystem and cost. For applying AHP method to launch vehicle subsystems reliability allocation, a Matlab code( for investigating compatibility and determining allocation weight factors by employing Matrix Eigen Vector Method) and a Excel sheet( for forming the comparison matrix) are employed. To this point, by using the outcomes of liquid-propellant launch vehicle conceptual design software (LVCD) which developed by authors, the launch vehicle specifications and operational time of each subsystems is derived and is feed to this methodology as input. The results of applying this method to launch vehicle reliability allocation for the second stage of a launch vehicle, shows the error of this method below 2%. It is clear that this small error in reliability issues in conceptual design phase is acceptable.
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 ...
Read More
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.
Z. Mehrafroz; S. Radpour
Volume 2, Issue 1 , April 2009, , Pages 35-42
Abstract
In this paper, reliability growth concepts and modeling methods have been studied and a reliability growth model for launch vehicles has been proposed. Numerical example shows how we can obtain the model parameters. A method for calculating the initial launch vehicle reliability is suggested, also a ...
Read More
In this paper, reliability growth concepts and modeling methods have been studied and a reliability growth model for launch vehicles has been proposed. Numerical example shows how we can obtain the model parameters. A method for calculating the initial launch vehicle reliability is suggested, also a method for estimating and validating of launch vehicle reliability in various number of launches with number of successes based on binomial distribution has been proposed. Results show after 10 successful launches we can conclude that launch vehicle reliability is between 0.741 and 1.
M. Mirshams; H. Karimi; H. Naseh
Volume 1, Issue 1 , September 2008, , Pages 21-36
Abstract
The principle goal of this paper is developing of Launch Vehicle Conceptual Design (LVCD) method based on combinational optimization of major design parameters. To this end, ten sub-algorithms will be presented in this design approach. Mass distribution of different stages to launch maximum payload mass ...
Read More
The principle goal of this paper is developing of Launch Vehicle Conceptual Design (LVCD) method based on combinational optimization of major design parameters. To this end, ten sub-algorithms will be presented in this design approach. Mass distribution of different stages to launch maximum payload mass to the orbit, pitch program trajectory to get to the maximum final velocity, and providing minimum velocity loss due to gravity, and also minimum axial acceleration of various stages of launch vehicle will be optimized as the results of the presented approach. The optimization process is performed subject to the restrictions. Also, the performance index is optimized in a mutual iteration mechanism. Evaluation and verification of the presented method is performed using available data of two and three-stage launch vehicles.
M. Ebrahimi; J. Jodey; J. Roshanian
Volume 1, Issue 1 , September 2008, , Pages 47-56
Abstract
Abstract-Multidisciplinary Design Optimization (MDO) approaches have significant effects on aerospace vehicle design methodology. In designing next generation space launch systems, MDO processes will face new and greater challenges. Needs to improve conceptual design capabilities have required an increase ...
Read More
Abstract-Multidisciplinary Design Optimization (MDO) approaches have significant effects on aerospace vehicle design methodology. In designing next generation space launch systems, MDO processes will face new and greater challenges. Needs to improve conceptual design capabilities have required an increase in the fidelity of empirical disciplinary models, improved design solutions and optimization methods, and reduced workload and design cycle time through advanced frameworks. Such a procedure could identify feasible designs and generate comparison and sensitivity data during optimization.This study uses a System Sensitivity Analysis method to optimize multidisciplinary design of a two-stage Small Solid Propellant Launch Vehicle (SSPLV) based on minimum launch mass. Suitable design variables and technological and functional constraints are considered, both at the system and discipline levels. Propulsion, weight, geometry and trajectory simulation disciplines are used in an appropriate combination. A Generalized Sensitivity Equation (GSE) is derived and solved, and the results of this equation are used for optimization. Comparing the results with the well known gradient based optimization methods proves the ability of the SSA method to reduce computation time.
