Low Thrust Space Vehicle Trajectory Optimization Using Regularized Variables
Author: K. J. Schwenzfeger
Publisher:
Published: 1974
Total Pages: 44
ISBN-13:
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Low Thrust Space Vehicle Trajectory Optimization Using Regularized Variables
Author: K. J. Schwenzfeger
Publisher:
Published: 1974
Total Pages: 44
ISBN-13:
DOWNLOAD EBOOKOptimizing the trajectory of a low thrust space vehicle usually means solving a nonlinear two point boundary value problem. In general, accuracy requirements necessitate extensive computation times. In celestial mechanics, regularizing transformations of the equations of motion are used to eliminate computational and analytical problems that occur during close approaches to gravitational force centers. It was shown in previous investigations that regularization in the formulation of the trajectory optimization problem may reduce the computation time. In this study, a set of regularized equations describing the optimal trajectory of a continuously thrusting space vehicle is derived. The computational characteristics of the set are investigated and compared to the classical Newtonian unregularized set of equations. The comparison is made for low thrust, minimum time, escape trajectories and numerical calculations of Keplerian orbits. The comparison indicates that in the cases investigated for bad initial guesses of the known boundary values a remarkable reduction in the computation time was achieved. Furthermore, the investigated set of regularized equations shows high numerical stability even for long duration flights and is less sensitive to errors in the guesses of the unknown boundary values.
Trajectory Optimization Using Regularized Variables
Author: B.D. Tapley
Publisher:
Published: 1968
Total Pages: 0
ISBN-13:
DOWNLOAD EBOOKSpacecraft Trajectory Optimization
Author: Bruce A. Conway
Publisher: Cambridge University Press
Published: 2010-08-23
Total Pages: 313
ISBN-13: 113949077X
DOWNLOAD EBOOKThis is a long-overdue volume dedicated to space trajectory optimization. Interest in the subject has grown, as space missions of increasing levels of sophistication, complexity, and scientific return - hardly imaginable in the 1960s - have been designed and flown. Although the basic tools of optimization theory remain an accepted canon, there has been a revolution in the manner in which they are applied and in the development of numerical optimization. This volume purposely includes a variety of both analytical and numerical approaches to trajectory optimization. The choice of authors has been guided by the editor's intention to assemble the most expert and active researchers in the various specialities presented. The authors were given considerable freedom to choose their subjects, and although this may yield a somewhat eclectic volume, it also yields chapters written with palpable enthusiasm and relevance to contemporary problems.
NASA Technical Report
Author: United States. National Aeronautics and Space Administration
Publisher:
Published: 1973
Total Pages: 936
ISBN-13:
DOWNLOAD EBOOKDesign of Trajectory Optimization Approach for Space Maneuver Vehicle Skip Entry Problems
Author: Runqi Chai
Publisher: Springer
Published: 2019-07-30
Total Pages: 207
ISBN-13: 9811398453
DOWNLOAD EBOOKThis book explores the design of optimal trajectories for space maneuver vehicles (SMVs) using optimal control-based techniques. It begins with a comprehensive introduction to and overview of three main approaches to trajectory optimization, and subsequently focuses on the design of a novel hybrid optimization strategy that combines an initial guess generator with an improved gradient-based inner optimizer. Further, it highlights the development of multi-objective spacecraft trajectory optimization problems, with a particular focus on multi-objective transcription methods and multi-objective evolutionary algorithms. In its final sections, the book studies spacecraft flight scenarios with noise-perturbed dynamics and probabilistic constraints, and designs and validates new chance-constrained optimal control frameworks. The comprehensive and systematic treatment of practical issues in spacecraft trajectory optimization is one of the book’s major features, making it particularly suited for readers who are seeking practical solutions in spacecraft trajectory optimization. It offers a valuable asset for researchers, engineers, and graduate students in GNC systems, engineering optimization, applied optimal control theory, etc.
Optimization of Low-thrust Spacecraft Trajectories by Direct Shooting Methods [microform]
Author: Christopher Rampersad
Publisher: Library and Archives Canada = Bibliothèque et Archives Canada
Published: 2004
Total Pages: 188
ISBN-13: 9780612951822
DOWNLOAD EBOOKThe direct approach for trajectory optimization was found to be very robust. For most problems, solutions were obtained even with poor initial guesses for the controls. The direct approach was also found to be only slightly less accurate than the indirect methods found in the literature (within 0.7%). The present study investigates minimum-time and minimum-fuel low-thrust trajectory problems via a single shooting direct method. Various Earth-based and interplanetary case studies have been examined and have yielded good agreement with similar cases in the literature. Furthermore, new near-optimal trajectory problems have been successfully solved. A multiple-orbit thrust parameterization strategy was also developed to solve near-optimal very-low-thrust Earth-based transfers. Lastly, this thesis examines the use of the high-accuracy complex-step derivative approximation method for solving low-thrust transfer problems. For certain very nonlinear transfer problems, the complex-step derivative approximation was found to increase the robustness of the single shooting direct method.
Direct Optimization of Three-dimensional, Low-thrust Space Trajectories with Variable Path Constraints
Author: Adria Batet Farre
Publisher:
Published: 2015
Total Pages:
ISBN-13:
DOWNLOAD EBOOKLow-thrust propulsion systems are growing in popularity for both Earth orbiting satellites and scientific spacecraft on interplanetary missions. This is thanks to the ability of these systems of traveling during more time and in a more efficient way. Moreover, space trajectories can be optimized in time or fuel by defining an optimal control problem and solving it via indirect or direct methods. Therefore, through this project a solver to optimize, via direct transcription and collocation, three-dimensional, low-thrust space trajectories with variable path constraints in a time or fuel optimal way will be implemented. For doing so, we will first talk about the advantages of low-thrust propulsion for long missions when compared to the chemical ones. Once these systems will have been introduced, we will define the optimal control problem via direct transcription and collocation. Also, we will see how low-thrust orbital transfers can be defined as an optimal control problem in order to be optimized for the transfer time or fuel consumption, including the mass flow equation in the dynamics of the problem and the decrease of available thrust that the engine will suffer as it moves away from the Sun as the path constraint. Then, we will implement the optimization solver using Matlab and the open source software package for large-scale nonlinear optimization IPOPT. This code will be organized in a logical way according to the optimal control problems resolution with IPOPT in order to ease its understanding and to enhance its clarity. Finally, some examples will be run in order to display their results and compare them. These examples will be defined using CubeSats with two different models of electro-spray propulsion engines, which have been proportioned by the department of aerospace science and technology of the Politecnico di Milano. This way, we will achieve a more realistic approach. Both models will be used for both time and fuel optimal problems, in order to prove the validity of the solver. The low-thrust orbital transfers stated will be between the Earth's orbit around the Sun and a ballistic capture precomputed point from where the spacecraft will be "picked up" by Mars.
