Optimal Trajectory Reconfiguration And Retargeting For A Reusable Launch Vehicle
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Optimal Trajectory Reconfiguration And Retargeting For The X 33 Reusable Launch Vehicle
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Author : Patrick J. Shaffer
language : en
Publisher:
Release Date : 2004-09-01
Optimal Trajectory Reconfiguration And Retargeting For The X 33 Reusable Launch Vehicle written by Patrick J. Shaffer and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004-09-01 with categories.
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.
Optimal Trajectory Reconfiguration And Retargeting For A Reusable Launch Vehicle
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Author :
language : en
Publisher:
Release Date : 2005
Optimal Trajectory Reconfiguration And Retargeting For A Reusable Launch Vehicle written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with categories.
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.
Fault Tolerant Optimal Trajectory Generation For Reusable Launch Vehicles
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Author : Patrick J. Shaffer
language : en
Publisher:
Release Date : 2006
Fault Tolerant Optimal Trajectory Generation For Reusable Launch Vehicles written by Patrick J. Shaffer and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with Launch vehicles (Astronautics) categories.
Reconfigurable inner-loop control laws improve the fault tolerance of a vehicle to control effector failures; however, in order to preserve stability, the unfailed effectors may be deployed to off-nominal positions to compensate for undesirable perturbations caused by the failed effectors. The effectors acting under the influence of a reconfigurable control law can produce significant perturbations to the nominal forces produced by the wing and body and can also affect the range of flight conditions over which the vehicle can be controlled. Three degree-of-freedom (3 DOF) dynamical models used in trajectory optimization for aerospace vehicles typically include wing-body aerodynamic force effects but ignore the aerodynamic forces produced by the control surfaces. In this work, a method for including these trim effects as well as control induced trajectory constraints in a 3 DOF model is presented.
Journal Of Guidance Control And Dynamics
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Author :
language : en
Publisher:
Release Date : 2007
Journal Of Guidance Control And Dynamics written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with Airplanes categories.
A Reconfigurable Guidance Approach For Reusable Launch Vehicles
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Author :
language : en
Publisher:
Release Date : 2001
A Reconfigurable Guidance Approach For Reusable Launch Vehicles written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001 with categories.
A guidance system with reconfiguration capabilities has been developed for reusable launch vehicles (RLVs). The focus of the development is on reconfiguration after a catastrophic effector failure during final approach - a failure that would otherwise cause loss of the vehicle. We assume here that the vehicle employs a reconfigurable inner-loop control system that recovers some maneuvering capabilities and maintains attitude stability. However, for RLVs, it is often the case that nominal performance cannot be fully recovered, and the outer-loop guidance system must account for the degraded response characteristics. Two approaches are presented. The first approach augments the existing production guidance system with adaptation capabilities. A case study shows that stability is maintained following a primary pitch effector failure. However, it is shown that the trajectory commands to the guidance loops must also be re-targeted in order to achieve a safe landing. The second approach employs an on-line optimal trajectory re-targeting algorithm. A database of neighboring optimal trajectories is encoded in an efficient manner and interrogated on line at regular intervals. Given the current states and certain vehicle parameters, this procedure generates optimal guidance commands and integrates the optimal trajectory to the next update point. A proof-of-concept study of this approach was performed. Following a primary speed control failure, the study shows that this approach achieves acceptable landing conditions.
Optimal Guidance Command Generation And Tracking For Reusable Launch Vehicle Reentry Preprint
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Author :
language : en
Publisher:
Release Date : 2006
Optimal Guidance Command Generation And Tracking For Reusable Launch Vehicle Reentry Preprint written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with categories.
The objective of this work is to develop a robust guidance and control architecture for autonomous reusable launch vehicles that incorporates elements of recent advances in the areas of optimal trajectory generation and reconfigurable control. This work integrates three separately developed methods to form a coherent architecture with the potential to manage control effector failures, vehicle structural/aerodynamic degradation, uncertainty, and external disturbances. Outer-loop guidance commands in the form of body-frame angular rates (roll, pitch, and yaw) are generated from an optimal reference trajectory that is computed off-line with a direct pseudospectral method and then tracked by a reconfigurable inner-loop control law. The appropriate open-loop state histories from the pseudo-four-degree-of-freedom reference trajectory are converted using a modified backstepping approach that complements the inner-loop control law in a six-degree-of-freedom simulation. The inner-loop control law is capable of reacting and compensating for off-nominal conditions by employing nonlinear reconfigurable control allocation, dynamic inversion, and model-following/anti-windup prefilters. The results show that the inner loop control can adequately track the desired optimal guidance commands; thus, confirming that applicability of this control architecture for future development involving on-line, optimal trajectory generation and high-fidelity guidance and control for reentry vehicles.
Optimal Trajectory Designs And Systems Engineering Analyses Of Reusable Launch Vehicles
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Author : Hung-i Bruce Tsai
language : en
Publisher:
Release Date : 2003
Optimal Trajectory Designs And Systems Engineering Analyses Of Reusable Launch Vehicles written by Hung-i Bruce Tsai and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with categories.
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.
Flight Test Results Of An Adaptive Guidance System For Reusable Launch Vehicles
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Author : John D. Schierman
language : en
Publisher:
Release Date : 2004
Flight Test Results Of An Adaptive Guidance System For Reusable Launch Vehicles written by John D. Schierman and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004 with Launch vehicles (Astronautics) categories.
To enable autonomous operations in future Reusable Launch Vehicles (RLVs), reconfigurable control and adaptive guidance will often be required to facilitate recovery of the mission following a major anomalous event such as an effector failure. An adaptive guidance system that works in conjunction with a reconfigurable controller and an autonomous trajectory command reshaping algorithm is presented. The guidance law utilizes a backstepping architecture to generate pitch rate commands that drive the inner-loop control system. Under extreme failure conditions the control surfaces can saturate in an attempt to meet commanded moments. In these cases, the guidance feedback gains are reduced to preserve stability margins in the guidance loops. A case study is presented that shows the benefits of the guidance gain adaptation. Without adjusting the gains, the guidance loops go unstable, whereas stability is maintained with gain reduction.
Redundant Inertial Measurement Unit Reconfiguration And Trajectory Replanning Of Launch Vehicle
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Author : Xuefeng Li
language : en
Publisher: Springer Nature
Release Date : 2022-09-22
Redundant Inertial Measurement Unit Reconfiguration And Trajectory Replanning Of Launch Vehicle written by Xuefeng Li and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022-09-22 with Technology & Engineering categories.
This book analyzes the problems to be solved urgently in the development of launch vehicle control system. The techniques of redundant Inertial Measurement Unit (IMU) reconfiguration and trajectory replanning are proposed aiming at the inertial device failures and power system failures during flight of launch vehicles, respectively. It introduces the background of redundant IMU reconfiguration and trajectory replanning technologies and models of launch vehicle dynamics and redundant strap-down IMUs. The approaches for redundant strap-down IMU fault detection, reconfiguration and trajectory replanning are proposed, putting forward a prospect for the development of launch vehicle control system. The content of this book is concise and highly pragmatic. It could serve as a reference for engineers and researchers engaged in the analysis, design and verification of launch vehicle control systems and also as a reference for graduate students and senior undergraduates majoring in navigation, guidance and control.
High Fidelity Real Time Trajectory Optimization For Reusable Launch Vehicles
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Author : Kevin P. Bollino
language : en
Publisher:
Release Date : 2006
High Fidelity Real Time Trajectory Optimization For Reusable Launch Vehicles written by Kevin P. Bollino and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with Engineering categories.
Creating simplicity out of complexity, this research abandons the traditional guidance and control architecture for aerospace vehicles and embraces a revolutionary concept based on the principles of nonlinear optimal control theory. Motivated by the emerging needs of the next generation of reusable space vehicles, an autonomous integrated guidance and control system is developed that provides a safe approach to the highly constrained and nonlinear reentry problem. A pseudospectral-based optimal guidance scheme is used to generate high-fidelity, vehicle-tailored solutions to reentry trajectory optimization and guidance problems. To provide an autonomous, onboard capability of satisfying final-approach requirements, a new method is developed that includes an automatic generation of landing constraints given any runway geometry. This unique and simple approach avoids significant complexities arising from previous ideas of trajectory segmentation, trimmed flight, and trajectory tracking schemes. When demonstrating the new ideas, it is shown that the proposed approach can easily compensate for large uncertainties and disturbances consisting of hurricane-force wind gusts. An investigation of these new principles for the complete, nonlinear six degree-of-freedom system dynamics indicates that while the results are quite promising, a substantial amount of new theoretical and computational problems remain open, particularly in the area of over-actuated dynamical systems.