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Optimal Guidance Command Generation And Tracking For Reusable Launch Vehicle Reentry Preprint
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Book Synopsis Optimal Guidance Command Generation and Tracking for Reusable Launch Vehicle Reentry (Preprint). by :
Download or read book Optimal Guidance Command Generation and Tracking for Reusable Launch Vehicle Reentry (Preprint). written by and published by . This book was released on 2006 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Optimal Guidance Command Generation and Tracking for the Reentry of a Reusable Launch Vehicle (PREPRINT). by :
Download or read book Optimal Guidance Command Generation and Tracking for the Reentry of a Reusable Launch Vehicle (PREPRINT). written by and published by . This book was released on 2006 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, optimal outer-loop guidance commands are generated from an off-line reference trajectory and then tracked by a reconfigurable inner-loop control law. The primary motivation for this work is a "stepping-stone" towards online, optimal trajectory generation, footprint determination, and retargeting capabilities in the presence of control effector failures or vehicle structural/ aerodynamic degradation, uncertainty, and external disturbances. The presented guidance and control architecture uses a 6-degree-of-freedom simulation and an inner-loop controller to track body-name angular rates (roll, pitch, and yaw), generated from an optimal psuedo-4-degree-of-freedom reference trajectory that is computed using a direct pseudo spectral method. The innerloop control law is capable of reacting and compensating for off-nominal conditions by employing its nonlinear 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 the applicability of this control architecture for future development involving on-line, optimal trajectory generation and high-fidelity footprint determination for reentry vehicles.
Book Synopsis Fault Tolerant Optimal Trajectory Generation for Reusable Launch Vehicles by : Patrick J. Shaffer
Download or read book Fault Tolerant Optimal Trajectory Generation for Reusable Launch Vehicles written by Patrick J. Shaffer and published by . This book was released on 2006 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis High-Fidelity Real-Time Trajectory Optimization for Reusable Launch Vehicles by : Kevin P. Bollino
Download or read book High-Fidelity Real-Time Trajectory Optimization for Reusable Launch Vehicles written by Kevin P. Bollino and published by . This book was released on 2006 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
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 Analysis of the Staging Maneuver and Booster Glideback Guidance for a Two-stage, Winged, Fully Reusable Launch Vehicle by : J. Christopher Naftel
Download or read book Analysis of the Staging Maneuver and Booster Glideback Guidance for a Two-stage, Winged, Fully Reusable Launch Vehicle written by J. Christopher Naftel and published by . This book was released on 1993 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Reconfigurable Guidance Approach for Reusable Launch Vehicles by :
Download or read book A Reconfigurable Guidance Approach for Reusable Launch Vehicles written by and published by . This book was released on 2001 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Sub-optimal Analytic Guidance for Reusable Launch Vehicles by : Katie Amanda Grantham
Download or read book Sub-optimal Analytic Guidance for Reusable Launch Vehicles written by Katie Amanda Grantham and published by . This book was released on 2003 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This thesis presents a guidance scheme for the Terminal Area Energy Management (TAEM) and Approach and Landing phases of flight for the next generation of reusable launch vehicles (RLVs). The guidance scheme presented is developed in two parts, the kappa guidance section and the touchdown trajectory section."--Abstract, p. iii.
Book Synopsis Adaptive Guidance Systems for Hypersonic Reusable Launch Vehicles by :
Download or read book Adaptive Guidance Systems for Hypersonic Reusable Launch Vehicles written by and published by . This book was released on 2001 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents an adaptive guidance system approach applied to hypersonic Reusable Launch Vehicles (RLVs). After an effector failure, it is assumed that the inner-closed-loop system utilizes a reconfigurable control algorithm to recover nominal maneuvering capabilities to the extent possible. However, nominal performance will typically not be fully recovered for RLVs, and the outer-loop guidance system must account for the degraded vehicle response. Two main approaches for the adaptive guidance system are presented. The first approach augments the existing production guidance system by adding adaptation capabilities. A case study shows that stability is maintained following a primary pitch effector failure. This is achieved by adapting gains in the guidance feedback loops. 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. Here, the calculus of variations is used to generate a database of admissible neighboring extremals. This database is then encoded in an efficient manner to generate mappings between the current states and vehicle capabilities and the costates defining the admissible optimal trajectories. These mappings are interrogated on-line at regular intervals to obtain the optimal guidance commands. A proof-of-concept case study of this approach shows that the final landing conditions are achieved following a primary speed control effector failure.
Book Synopsis Closed-loop Endo-atmospheric Ascent Guidance for Reusable Launch Vehicle by : Hongsheng Sun
Download or read book Closed-loop Endo-atmospheric Ascent Guidance for Reusable Launch Vehicle written by Hongsheng Sun and published by . This book was released on 2005 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation focuses on the development of a closed-loop endo-atmospheric ascent guidance algorithm for the 2nd generation reusable launch vehicle. Special attention has been given to the issues that impact on viability, complexity and reliability in on-board implementation. The algorithm is called once every guidance update cycle to recalculate the optimal solution based on the current flight condition, taking into account atmospheric effects and path constraints. This is different from traditional ascent guidance algorithms which operate in a simple open-loop mode inside atmosphere, and later switch to a closed-loop vacuum ascent guidance scheme. The classical finite difference method is shown to be well suited for fast solution of the constrained optimal three-dimensional ascent problem. The initial guesses for the solutions are generated using an analytical vacuum optimal ascent guidance algorithm. Homotopy method is employed to gradually introduce the aerodynamic forces to generate the optimal solution from the optimal vacuum solution. The vehicle chosen for this study is the Lockheed Martin X-33 lifting-body reusable launch vehicle. To verify the algorithm presented in this dissertation, a series of open-loop and closed-loop tests are performed for three different missions. Wind effects are also studied in the closed-loop simulations. For comparison, the solutions for the same missions are also obtained by two independent optimization softwares. The results clearly establish the feasibility of closed-loop endo-atmospheric ascent guidance of rocket-powered launch vehicles. ATO cases are also tested to assess the adaptability of the algorithm to autonomously incorporate the abort modes.
Book Synopsis Flight Test Results of an Adaptive Guidance System for Reusable Launch Vehicles by : John D. Schierman
Download or read book Flight Test Results of an Adaptive Guidance System for Reusable Launch Vehicles written by John D. Schierman and published by . This book was released on 2004 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
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 Model Predictive Control for Terminal Area Energy Management and Approach and Landing for a Reusable Launch Vehicle by :
Download or read book Model Predictive Control for Terminal Area Energy Management and Approach and Landing for a Reusable Launch Vehicle written by and published by . This book was released on 2002 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: The space industry plans to develop new reusable launch vehicles. The new vehicles will need advanced, new guidance and control systems. Since 1996 Draper Laboratory has been developing the next generation guidance and control for reusable launch vehicles in which guidance and control is integrated into one correlated system. Draper's research of integrated guidance and control originated with a single loop multivariable control scheme using time-invariant linear quadratic regulator theory. The research has since evolved into the use of model predictive control theory. The main focus of this thesis is the theory and design of model predictive control for entry of aerospace vehicles. The goal is to develop design criteria and guidelines explaining how to select the model predictive control parameters: prediction horizon, simulation rates, and weighting matrices. A secondary goal is to tightly couple an onboard trajectory generation algorithm with the model predictive controller to improve tracking performance and robustness. Favorable tracking is achieved through two model predictive control architectures, which are discussed. The first architecture has an inner loop stability augmentation system with model predictive control used as an outer loop. The second architecture replaces the inner and outer loops with a single model predictive controller. The two architectures demonstrate the flexibility of model predictive control to adapt to new vehicles; the model predictive control may be used to augment an existing inner loop or may be used as a stand-alone controller. The design focuses primarily on the architecture without a stability augmentation system.
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 Flight Mechanics and Control for an Unpowered Reusable Launch Vehicle by : Steven Edward McKee
Download or read book Flight Mechanics and Control for an Unpowered Reusable Launch Vehicle written by Steven Edward McKee and published by . This book was released on 2011 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new strategy has been developed to aid in allowing a reusable launch vehicle to complete the Trajectory Area Energy Management (TAEM) phase of reentry. Using the new trajectory planning and tracking strategy, the reusable launch vehicle will complete TAEM with a higher degree of accuracy than what has been accomplished in the past. The reusable launch vehicle will also be better prepared to adapt to unpredictable conditions, which in the past were a hindrance to an accurate and safe reentry. The new strategy is composed of two distinct components. The first component provides the vehicle with a new way to track the Heading Alignment Cone (HAC) using dynamic gain values. The new dynamic gains values are found through a combination of linearization, state-space representation, and pole-placement. The second component provides the vehicle with an extremely accurate groundtrack predictor. The groundtrack predictor allows the vehicle to accurately determine an ideal trajectory to the next reentry phase, Approach and Landing. The groundtrack predictor utilizes a combination of HAC size and location modifications in order to provide the vehicle with an accurate prediction.
Book Synopsis Model Predictive Control for Terminal Area Energy Management and Approach and Landing for a Reusable Launch Vehicle by : Robert Charles LePome
Download or read book Model Predictive Control for Terminal Area Energy Management and Approach and Landing for a Reusable Launch Vehicle written by Robert Charles LePome and published by . This book was released on 2002 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Onboard Trajectory Generation for the Unpowered Landing of Autonomous Reusable Launch Vehicles by : André René Girerd
Download or read book Onboard Trajectory Generation for the Unpowered Landing of Autonomous Reusable Launch Vehicles written by André René Girerd and published by . This book was released on 2001 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
