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Improvements To A Hybrid Algorithm For Rapid Generation Of 3 D Optimal Launch Vehicle Ascent Trajectories
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Book Synopsis Improvements to a Hybrid Algorithm for Rapid Generation of 3-D Optimal Launch Vehicle Ascent Trajectories by : Peter F. Gath
Download or read book Improvements to a Hybrid Algorithm for Rapid Generation of 3-D Optimal Launch Vehicle Ascent Trajectories written by Peter F. Gath and published by diplom.de. This book was released on 1999-12-15 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: Inhaltsangabe:Abstract: This thesis presents improvements to FLOAT, a hybrid analytical/numerical algorithm for rapid generation of three dimensional, optimal launch vehicle ascent trajectories. Improvements have been made to the terminal constraints, which are now available in a more general form to allow for an optimal attachment point to the target orbit.The existing algorithm also has been extended with logic that allows for vehicles with low thrust to weight ratios in the upper stage and successful convergence of problems with path constraints for normal force and angle of attack Another major extension made to the code is the introduction of coasting arcs. Coasting arcs are implemented using a completely analytical solution for the prediction of states and costates as well as for the required sensitivity matrix. This allows for a very fast and accurate calculation even with long coasting arcs. Finally, an approach for the optimization of start and end time of coast arcs is presented.This approach was implemented and the results of a test case compare very well with results generated with OTIS for the same case. At the end, suggestions for future development are made. Inhaltsverzeichnis:Table of Contents: Summaryi Acknowledgementsii Contentsiii Nomenclaturev Figuresviii Introduction1 1.Problem description3 1.1Describing the final orbit3 1.2Coordinate frame5 1.3Dynamic system6 1.4Initial conditions7 1.5Path constraints7 1.6Performance index7 1.7Terminal constraints8 1.8Solution method8 1.9Non-dimensionalization of the variables9 2.Solving the two-point boundary value problem10 2.1Vacuumsolution10 2.1.1Simplified model equations10 2.1.2Optimal control for vacuum solution11 2.1.3Thrust integrals and closed form solution for ascent in vacuum12 2.2Atmospheric solution13 2.2.1Dynamic system and collocation variables13 2.2.2Optimality condition to solve for 1b14 2.2.3Differential equations for the costate variables16 2.3Terminal constraints16 2.3.1Attaching at perigee17 2.3.2Free attachment point17 2.4Transversality conditions18 2.4.1Final costates for attaching at perigee18 2.4.2Final costates for free attachment point19 2.4.3Equatorial orbits22 2.5Adjusting final time22 2.6Computation procedure23 2.7Numerical results24 3.Low thrust upper stages27 3.1Typical low thrust case27 3.2Problems with low thrust upper stages28 3.3Upper stage modification30 3.4Advantage of free attachment point for low thrust [...]
Book Synopsis A Fixed-point Framework for Launch Vehicle Ascent Guidance by : Lijun Zhang
Download or read book A Fixed-point Framework for Launch Vehicle Ascent Guidance written by Lijun Zhang and published by . This book was released on 2006 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent, interests in responsive launch have highlighted the need for rapid and fully automated ascent guidance planning and guidance parameter generation for launch vehicles. This dissertation aims at developing methodology and algorithms for on-demand generation of optimal launch vehicle ascent trajectories from lift-off to achieving targeting conditions outside the atmosphere. The entire ascent trajectory from lift-off to final target point is divided into two parts: atmospheric ascent portion and vacuum ascent portion. The two portions are integrated via a fixed-point iteration based on the continuity condition at the switch point between atmospheric ascent portion and vacuum ascent portion. The previous research works on closed-loop endo-atmospheric ascent guidance shows that the classical finite difference method is well suited for fast solution of the constrained optimal three-dimensional ascent problem. The exploitation of certain unique features in the integration procedure between the atmospheric portion and vacuum portion and the finite difference method, allows us to cast the atmospheric ascent problem into a nested fixed-point iteration problem. Therefore a novel Fixed-Point Iteration algorithm is presented for solving the endo-atmospheric ascent guidance problem. Several approaches are also provided for facilitating the convergence of the fixed-point iteration. The exo-atmospheric ascent portion allows an optimal coast in between the two vacuum powered stages. The optimal coast enables more efficient usage of the propellant. The Analytical Multiple-Shooting algorithm is developed to find the optimal trajectory for this portion. A generic launch vehicle model is adopted in the numerical simulation. A series of open-loop and closed-loop simulations are performed. The results verify the effectiveness, robustness and reliability of the Fixed-Point Iteration (FPI) algorithm and Analytical Multiple-Shooting (AMS) algorithm developed in this research. In comparison to Finite Difference (FD) algorithm, the Fixed-Point Iteration algorithm is more adaptive to the "cold start" case for endo-atmospheric ascent guidance. The simulations also validate the feasibility of the methodology presented in this research in rapid panning and guidance for ascent through atmosphere.
Book Synopsis Design of Trajectory Optimization Approach for Space Maneuver Vehicle Skip Entry Problems by : Runqi Chai
Download or read book Design of Trajectory Optimization Approach for Space Maneuver Vehicle Skip Entry Problems written by Runqi Chai and published by Springer. This book was released on 2019-07-30 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 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.
Book Synopsis Optimal Three Dimensional Launch Vehicle Trajectories with Attitude and Attitude Rate Constraints by : Fred Teren
Download or read book Optimal Three Dimensional Launch Vehicle Trajectories with Attitude and Attitude Rate Constraints written by Fred Teren and published by . This book was released on 1969 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Optimal Guidance Law Development for an Advanced Launch System by : National Aeronautics and Space Adm Nasa
Download or read book Optimal Guidance Law Development for an Advanced Launch System written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-11-08 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research effort was to develop a real-time guidance approach for launch vehicles ascent to orbit injection. Various analytical approaches combined with a variety of model order and model complexity reduction have been investigated. Singular perturbation methods were first attempted and found to be unsatisfactory. The second approach based on regular perturbation analysis was subsequently investigated. It also fails because the aerodynamic effects (ignored in the zero order solution) are too large to be treated as perturbations. Therefore, the study demonstrates that perturbation methods alone (both regular and singular perturbations) are inadequate for use in developing a guidance algorithm for the atmospheric flight phase of a launch vehicle. During a second phase of the research effort, a hybrid analytic/numerical approach was developed and evaluated. The approach combines the numerical methods of collocation and the analytical method of regular perturbations. The concept of choosing intelligent interpolating functions is also introduced. Regular perturbation analysis allows the use of a crude representation for the collocation solution, and intelligent interpolating functions further reduce the number of elements without sacrificing the approximation accuracy. As a result, the combined method forms a powerful tool for solving real-time optimal control problems. Details of the approach are illustrated in a fourth order nonlinear example. The hybrid approach is then applied to the launch vehicle problem. The collocation solution is derived from a bilinear tangent steering law, and results in a guidance solution for the entire flight regime that includes both atmospheric and exoatmospheric flight phases. Calise, Anthony J. and Leung, Martin S. K. Unspecified Center ADVANCED LAUNCH SYSTEM (STS); ALGORITHMS; ASCENT TRAJECTORIES; INJECTION GUIDANCE; LAUNCH VEHICLES; OPTIMAL CONTROL; PERTURBATION THEORY; PROBLEM SOLVING; REAL TIME OPERATION; SPACEC...
Book Synopsis Rapid Near-Optimal Trajectory Generation and Guidance Law Development for Single-Stage-To-Orbit Airbreathing Vehicles by : National Aeronautics and Space Adm Nasa
Download or read book Rapid Near-Optimal Trajectory Generation and Guidance Law Development for Single-Stage-To-Orbit Airbreathing Vehicles written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-11-06 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: General problems associated with on-board trajectory optimization, propulsion system cycle selection, and with the synthesis of guidance laws were addressed for an ascent to low-earth-orbit of an air-breathing single-stage-to-orbit vehicle. The NASA Generic Hypersonic Aerodynamic Model Example and the Langley Accelerator aerodynamic sets were acquired and implemented. Work related to the development of purely analytic aerodynamic models was also performed at a low level. A generic model of a multi-mode propulsion system was developed that includes turbojet, ramjet, scramjet, and rocket engine cycles. Provisions were made in the dynamic model for a component of thrust normal to the flight path. Computational results, which characterize the nonlinear sensitivity of scramjet performance to changes in vehicle angle of attack, were obtained and incorporated into the engine model. Additional trajectory constraints were introduced: maximum dynamic pressure; maximum aerodynamic heating rate per unit area; angle of attack and lift limits; and limits on acceleration both along and normal to the flight path. The remainder of the effort focused on required modifications to a previously derived algorithm when the model complexity cited above was added. In particular, analytic switching conditions were derived which, under appropriate assumptions, govern optimal transition from one propulsion mode to another for two cases: the case in which engine cycle operations can overlap, and the case in which engine cycle operations are mutually exclusive. The resulting guidance algorithm was implemented in software and exercised extensively. It was found that the approximations associated with the assumed time scale separation employed in this work are reasonable except over the Mach range from roughly 5 to 8. This phenomenon is due to the very large thrust capability of scramjets in this Mach regime when sized to meet the requirement for ascent to orbit. By accounting for flight path angl...
Book Synopsis Autonomous Trajectory Planning and Guidance Control for Launch Vehicles by : Zhengyu Song
Download or read book Autonomous Trajectory Planning and Guidance Control for Launch Vehicles written by Zhengyu Song and published by Springer Nature. This book was released on 2023-04-15 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book highlights the autonomous and intelligent flight control of future launch vehicles for improving flight autonomy to plan ascent and descent trajectories onboard, and autonomously handle unexpected events or failures during the flight. Since the beginning of the twenty-first century, space launch activities worldwide have grown vigorously. Meanwhile, commercial launches also account for the booming trend. Unfortunately, the risk of space launches still exists and is gradually increasing in line with the rapidly rising launch activities and commercial rockets. In the history of space launches, propulsion and control systems are the two main contributors to launch failures. With the development of information technologies, the increase of the functional density of hardware products, the application of redundant or fault-tolerant solutions, and the improvement of the testability of avionics, the launch losses caused by control systems exhibit a downward trend, and the failures induced by propulsion systems become the focus of attention. Under these failures, the autonomous planning and guidance control may save the missions. This book focuses on the latest progress of relevant projects and academic studies of autonomous guidance, especially on some advanced methods which can be potentially real-time implemented in the future control system of launch vehicles. In Chapter 1, the prospect and technical challenges are summarized by reviewing the development of launch vehicles. Chapters 2 to 4 mainly focus on the flight in the ascent phase, in which the autonomous guidance is mainly reflected in the online planning. Chapters 5 and 6 mainly discuss the powered descent guidance technologies. Finally, since aerodynamic uncertainties exert a significant impact on the performance of the ascent / landing guidance control systems, the estimation of aerodynamic parameters, which are helpful to improve flight autonomy, is discussed in Chapter 7. The book serves as a valuable reference for researchers and engineers working on launch vehicles. It is also a timely source of information for graduate students interested in the subject.
Book Synopsis Advanced Technologies in Flow Dynamics and Combustion in Propulsion and Power by : Lei Luo
Download or read book Advanced Technologies in Flow Dynamics and Combustion in Propulsion and Power written by Lei Luo and published by Frontiers Media SA. This book was released on 2022-08-05 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Optimal Ascent Trajectories for Advanced Launch Vehicles by : W. Buhl
Download or read book Optimal Ascent Trajectories for Advanced Launch Vehicles written by W. Buhl and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Optimal Trajectory Designs and Systems Engineering Analyses of Reusable Launch Vehicles by : Hung-i Bruce Tsai
Download or read book Optimal Trajectory Designs and Systems Engineering Analyses of Reusable Launch Vehicles written by Hung-i Bruce Tsai and published by . This book was released on 2003 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt: Realizing a reusable launch vehicle (RLV) that is low cost with highly effective launch capability has become the "Holy Grail" within the aerospace community world-wide. Clear understanding of the vehicle's operational limitations and flight characteristics in all phases of the flight are preponderant components in developing such a launch system. This dissertation focuses on characterizing and designing the RLV optimal trajectories in order to aid in strategic decision making during mission planning in four areas: 1) nominal ascent phase, 2) abort scenarios and trajectories during ascent phase including abort-to-orbit (ATO), transoceanic-abort-landing (TAL) and return-to-launch-site (RTLS), 3) entry phase (including footprint), and 4) systems engineering aspects of such flight trajectory design. The vehicle chosen for this study is the Lockheed Martin X-33 lifting-body design that lifts off vertically with two linear aerospike rocket engines and lands horizontally. An in-depth investigation of the optimal endo-atmospheric ascent guidance parameters such as earliest abort time, engine throttle setting, number of flight phases, flight characteristics and structural design limitations will be performed and analyzed to establish a set of benchmarks for making better trade-off decisions. Parametric analysis of the entry guidance will also be investigated to allow the trajectory designer to pinpoint relevant parameters and to generate optimal constrained trajectories. Optimal ascent and entry trajectories will be generated using a direct transcription method to cast the optimal control problem as a nonlinear programming problem. The solution to the sparse nonlinear programming problem is then solved using sequential quadratic programming. Finally, guidance system hierarchy studies such as work breakdown structure, functional analysis, fault-tree analysis, and configuration management will be developed to ensure that the guidance system meets the definition of vehicle design requirements and constraints.
Book Synopsis International Aerospace Abstracts by :
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 934 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1989 with total page 1134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Optimal Trajectory Reconfiguration and Retargeting for the X-33 Reusable Launch Vehicle by : Patrick J. Shaffer
Download or read book Optimal Trajectory Reconfiguration and Retargeting for the X-33 Reusable Launch Vehicle written by Patrick J. Shaffer and published by . This book was released on 2004-09-01 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis considers the problem of generating optimal entry trajectories for a reusable launch vehicle following a control surface failure. The thesis builds upon the work of Dr. David Doman, Dr. Michael Oppenheimer and Dr. Michael Bolender of the Air Vehicles Directorate, Air Force Research Lab Dayton Ohio. The primary focus of this work is to demonstrate the feasibility of inner loop reconfiguration and outer loop trajectory retargeting and replanning for the X-33 reusable launch vehicle (RLV) following the imposition of a control surface failure. The trajectory generation model employs path constraints generated by an AFRL trim deficiency algorithm coupled with an inner loop control allocator and aerodynamic database that captures the full 6-DOF vehicle aerodynamic effects while utilizing an outer loop 3-DOF model. The resulting optimal trajectory does not violate the trim deficiency constraints and provides additional margins for trajectories flown during failure conditions. The footprints generated by the thesis show that contemporary footprint analysis for vehicles experiencing control surface failures are overly optimistic when compared to those footprints that consider vehicle aerodynamic stability and realistic landable attitudes at the threshold of the landing runway. The results of the thesis also show the performance reductions resulting from decoupling the inner and outer loop and that trajectories can be generated to the landing runway without using a region of terminal area energy management.
Book Synopsis Application of a Modified Genetic Algorithm to the Trajectory Optimization of a Launch Vehicle Second Stage by : Mrugesh Dalwadi
Download or read book Application of a Modified Genetic Algorithm to the Trajectory Optimization of a Launch Vehicle Second Stage written by Mrugesh Dalwadi and published by . This book was released on 2010 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The demand for increased payload or reduced propellant requirements requires the trajectories of spacecrafts and launch vehicles to be optimized. In order to achieve the optimum trajectory, a recently proposed modified Genetic Algorithm is combined with non-linear programming techniques are presented here. It is then applied to a launch vehicle ascent trajectory optimization. As opposite to the conventional genetic algorithm, here for selection criteria, penalty function along with fitness function is used with comparatively large penalty parameter value, which makes it powerful enough to achieve optimization for desired objective function value. The algorithm is implemented in MATLAB and validated by applying it to the constrained brachistochrone problem. It is then applied to the second stage trajectory of a nanosat launch vehicle. The vehicle was designed assuming a gravity turn trajectory, which is accomplished by trial and error. With the proposed automatic approach, the mass of payload achieved is 9.0 kg at a final altitude of 250.21 km and at a velocity of 7.86 km/s. This value is within the constraints imposed here and results show that it is essentially the same as that of the gravity trajectory under the exact same final states, thus demonstrating the ability of the optimizer to automatically narrow down the area of search. The performance then can be further improved by conventional optimizers.
Book Synopsis Optimal Trajectory Reconfiguration and Retargeting for a Reusable Launch Vehicle by :
Download or read book Optimal Trajectory Reconfiguration and Retargeting for a Reusable Launch Vehicle written by and published by . This book was released on 2005 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Autonomous reusable launch vehicles (RLV) are being pursued as low-cost alternatives to expendable launch vehicles and the Shuttle. The employment of autonomous reusable launch vehicles requires additional guidance and control robustness to fulfill the role of an adaptive human pilot, in the event of failures or unanticipated conditions. The guidance and control of these vehicles mandate new guidance strategies that are able to identify and adapt to vehicle failures during the flight and still return to earth safely. This work utilizes an online trim algorithm that provides the outer loop with the feasible range of Mach number and angle of attack, for which the vehicle can be rotationally trimmed. The algorithm allows one to include 6-degree-of-freedom (DOF) trim effects and constraints in a reduced order dynamical model which is used in the solution of an optimal control problem. A direct pseudospectral method is used to solve a two-point-boundary-value problem which determines the optimal entry trajectory subject to appropriate constraints such as normal load, dynamic pressure limits, heat load limits, and state dependent constraints.
Book Synopsis Automated Trajectory Generation and Guidance for a New Launch Vehicle Flight Phases by : Kenneth R. Horneman
Download or read book Automated Trajectory Generation and Guidance for a New Launch Vehicle Flight Phases written by Kenneth R. Horneman and published by . This book was released on 2010 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: Much effort has been put into developing technologies for next generation re-usable launch vehicles. Fully re-usable launch vehicles include a booster stage that is designed to land, usually near the launch site, after it has released the upper-stage, which continues to orbit. The fuel reserve needed to turn the booster stage around will usually be minimal For this reason, once the booster stage has completed a rocket-back maneuver, it will typically be at a high altitude (exo-atmospheric) but with low kinetic energy and a steep flight path angle on re-entry. Traditional re-entry guidance is designed for vehicles with a high velocity, and shallow flight path angle, and thus these traditional approaches are not appropriate for a low energy re-entry (LOER). The current research presents a set of guidance algorithms that will successfully guide a vehicle to landing starting from LOER condition. The guidance algorithms are designed to ensure the vehicle can achieve near optimal range performance when required and also to execute a sharp pull-up maneuver that balances the load factor constraint against the need to pull-up quickly before the dynamic pressure constraint is exceeded. The guidance approach has been tested for a wide variety of vehicles and mission scenarios, including more traditional initial conditions that would occur at the end of a High Energy Re-entry (HIER) from orbit. Thus, the guidance approach we have developed can be used as a more robust version of Terminal Area Energy Management (TAEM) guidance, as well as for LOER and has been tested for a wide range of vehicles, including the Space Shuttle and vehicles with a wide variety of L/D capability. Significant development has also gone into the engineering considerations needed to implement the guidance algorithms on a real vehicle. Program execution time, application of vehicle constraints, trajectory repeatability and other factors are all addressed in order to meet this need.
Book Synopsis Closed-loop Nominal and Abort Atmospheric Ascent Guidance for Rocket-powered Launch Vehicles by : Greg A. Dukeman
Download or read book Closed-loop Nominal and Abort Atmospheric Ascent Guidance for Rocket-powered Launch Vehicles written by Greg A. Dukeman and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced ascent guidance algorithm for rocket-powered launch vehicles is developed. The ascent guidance function is responsible for commanding attitude, throttle and setting during the powered ascent phase of flight so that the vehicle attains target cutoff conditions in a near-optimal manner while satisfying path constraints such as maximum allowed bending moment and maximum allowed axial acceleration. This algorithm cyclically solves the calculus-of-variations two-point boundary-value problem starting at vertical rise completion through orbit insertion. This is different from traditional ascent guidance algorithms which operate in an open-loop mode until the high dynamic pressure portion of the trajectory is over, at which time there is a switch to a closed loop guidance mode that operates under the assumption of negligible aerodynamic forces. The main contribution of this research is an algorithm of the predictor-corrector type wherein the state/costate system is propagated with known (navigated) initial state and guessed initial costate to predict the state/costate at engine cutoff. The initial costate guess is corrected, using a multi-dimensional Newton?s method, based on errors in the terminal state constraints and the transversality conditions. Path constraints are enforced within the propagation process. A modified multiple shooting method is shown to be a very effective numerical technique for this application. Results for a single stage to orbit launch vehicle are given. In addition, the formulation for the free final time multi-arc trajectory optimization problem is given. Results for a two-stage launch vehicle burn-coast-burn ascent to orbit in a closed-loop guidance mode are shown. An abort to landing site formulation of the algorithm and numerical results are presented. A technique for numerically treating the transversality conditions is discussed that eliminates part of the analytical and coding burden associated with optimal control theory.
