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Direct Adaptive Control For Stability And Command Augmentation System Of An Air Breathing Hypersonic Vehicle
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Book Synopsis Direct Adaptive Control for Stability and Command Augmentation System of an Air-breathing Hypersonic Vehicle by : Ron Aditya
Download or read book Direct Adaptive Control for Stability and Command Augmentation System of an Air-breathing Hypersonic Vehicle written by Ron Aditya and published by . This book was released on 2015 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper we explore a Direct Adaptive Control scheme for stabilizing a non-linear, physics based model of the longitudinal dynamics for an air breathing hypersonic vehicle. The model, derived from first principles, captures the complex interactions between the propulsion system, aerodynamics, and structural dynamics. The linearized aircraft dynamics show unstable and non-minimum phase behavior. It also shows a strong short period coupling with the fuselage-bending mode. The value added by direct adaptive control and the theoretical requirements for stable convergent operation is displayed. One of the main benefits of the Directive Adaptive Control is that it can be implemented knowing very little detail about the plant. The implementation uses only measured output feedback to accomplish the adaptation. A stability analysis is conducted on the linearized plant to understand the complex aero-propulsion and structural interactions. The multivariable system possesses certain characteristics beneficial to the adaptive control scheme; we discuss these advantages and ideas for future work.
Book Synopsis Nonlinear Adaptive Controller Design for Air-breathing Hypersonic Vehicles by : Lisa Fiorentini
Download or read book Nonlinear Adaptive Controller Design for Air-breathing Hypersonic Vehicles written by Lisa Fiorentini and published by . This book was released on 2010 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: This dissertation presents the design of two nonlinear robust controllers for an air-breathing hypersonic vehicle model capable of providing stable tracking of velocity and altitude (or flight-path angle) reference trajectories. To overcome the analytical intractability of a dynamical model derived from first principles, a simplified control-oriented model is used for control design. The control-oriented model retains the most important features of the model from which it was derived, including the non-minimum phase characteristic of the flight-path angle dynamics and strong couplings between the engine and flight dynamics. The first control design considers as control inputs the fuel equivalence ratio and the elevator and canard deflections. A combination of nonlinear sequential loop-closure and adaptive dynamic inversion has been adopted for the design of a dynamic state-feedback controller. An important contribution given by this work is the complete characterization of the internal dynamics of the model has been derived for Lyapunov-based stability analysis of the closed-loop system, which includes the structural dynamics. The results obtained address the issue of stability robustness with respect to both parametric model uncertainty, which naturally arises in adopting reduced-complexity models for control design, and dynamic perturbations due to the flexible dynamics. In the second control design a first step has been taken in extending those results in the case in which only two control inputs are available, namely the fuel equivalence ratio and the elevator deflection. The extension of these results to this new framework is not trivial since several issues arise. First of all, the vehicle dynamics are characterized by exponentially unstable zero-dynamics when longitudinal velocity and flight-path angle are selected as regulated output. This non-minimum phase behavior arises as a consequence of elevator-to-lift coupling. In the previous design the canard was strategically used to adaptively decouple lift from elevator command, thus rendering the system minimum phase. Moreover, the canard input was also employed to enforce the equilibrium at the desired trim condition and to provide a supplementary stabilizing action. As a result, when this control input is not assumed to be available, the fact that the system needs to be augmented with an integrator (to reconstruct the desired equilibrium) and the non-minimum phase behavior have a strong impact on the control design. In these preliminary results the flexible effects are not taken into account in the stability analysis but are considered as a perturbation and included in the simulation model. The approach considered utilizes a combination of adaptive and robust design methods based on both classical and recently developed nonlinear design tools. As a result, the issue of robustness with respect to parameter uncertainties is addressed also in this control design. Simulation results on the full nonlinear model show the effectiveness of both controllers.
Book Synopsis Geometry Modeling and Adaptive Control of Air-breathing Hypersonic Vehicles by : Tyler J. Vick
Download or read book Geometry Modeling and Adaptive Control of Air-breathing Hypersonic Vehicles written by Tyler J. Vick and published by . This book was released on 2014 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: Air-breathing hypersonic vehicles have the potential to provide global reach and affordable access to space. Recent technological advancements have made scramjet-powered flight achievable, as evidenced by the successes of the X-43A and X-51A flight test programs over the last decade. Air-breathing hypersonic vehicles present unique modeling and control challenges in large part due to the fact that scramjet propulsion systems are highly integrated into the airframe, resulting in strongly coupled and often unstable dynamics. Additionally, the extreme flight conditions and inability to test fully integrated vehicle systems larger than X-51 before flight leads to inherent uncertainty in hypersonic flight. This thesis presents a means to design vehicle geometries, simulate vehicle dynamics, and develop and analyze control systems for hypersonic vehicles. First, a software tool for generating three-dimensional watertight vehicle surface meshes from simple design parameters is developed. These surface meshes are compatible with existing vehicle analysis tools, with which databases of aerodynamic and propulsive forces and moments can be constructed. A six-degree-of-freedom nonlinear dynamics simulation model which incorporates this data is presented. Inner-loop longitudinal and lateral control systems are designed and analyzed utilizing the simulation model. The first is an output feedback proportional-integral linear controller designed using linear quadratic regulator techniques. The second is a model reference adaptive controller (MRAC) which augments this baseline linear controller with an adaptive element. The performance and robustness of each controller are analyzed through simulated time responses to angle-of-attack and bank angle commands, while various uncertainties are introduced. The MRAC architecture enables the controller to adapt in a nonlinear fashion to deviations from the desired response, allowing for improved tracking performance, stability, and robustness.
Book Synopsis Adaptive Control of Nonminimum Phase Aerospace Vehicles by : Anusha Mannava
Download or read book Adaptive Control of Nonminimum Phase Aerospace Vehicles written by Anusha Mannava and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the second part, control design for HSV is attempted through a weaker coupling, i.e. by lift control. An internal model is used for redefining tracking errors and forming a loop interconnection with pitch angle and pitch-rate. This loop generates zero dynamics which must be stabilized. The pitch dynamics are steered towards a command input by selecting the input to the internal model. The internal model is stabilized by the selection of the command input to the pitch dynamics. This successive redefinition of the regulated outputs between the nested zero dynamics is the critical design element for overall system stability. The loop interconnection between the internal model and the pitch dynamics is stabilized by a small-gain analysis. In this design, coefficients of all three-lift,drag and moment coefficients are estimated by adaptive update laws. The main contribution of this dissertation is a demonstration of adaptive control design for nonlinear nonminimum phase systems using only thrust and elevator deflection as control inputs with the air-breathing hypersonic vehicle as a case study.
Book Synopsis Adaptive Control of a Generic Hypersonic Vehicle by : Daniel Philip Wiese
Download or read book Adaptive Control of a Generic Hypersonic Vehicle written by Daniel Philip Wiese and published by . This book was released on 2013 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a an adaptive augmented, gain-scheduled baseline LQR-PI controller applied to the Road Runner six-degree-of-freedom generic hypersonic vehicle model. Uncertainty in control effectiveness, longitudinal center of gravity location, and aerodynamic coefficients are introduced in the model, as well as sensor bias and noise, and input time delays. The performance of the baseline controller is compared to the same design augmented with one of two different model-reference adaptive controllers: a classical open-loop reference model design, and modified closed-loop reference model design. Both adaptive controllers show improved command tracking and stability over the baseline controller when subject to these uncertainties. The closed-loop reference model controller offers the best performance, tolerating a reduced control effectiveness of 50%, rearward center of gravity shift of -0.9 to -1.6 feet (6-11% of vehicle length), aerodynamic coefficient uncertainty scaled 4x the nominal value, and sensor bias of +1.6 degrees on sideslip angle measurement. The closed-loop reference model adaptive controller maintains at least 73% of the delay margin provided by the robust baseline design, tolerating input time delays of between 18-46 ms during 3 degree angle of attack doublet, and 80 degree roll step commands.
Book Synopsis Nonlinear Robust/adaptive Controller Design for an Air-breathing Hypersonic Vehicle Model by : Lisa Fiorentini
Download or read book Nonlinear Robust/adaptive Controller Design for an Air-breathing Hypersonic Vehicle Model written by Lisa Fiorentini and published by . This book was released on 2007 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: This thesis presents the design of two nonlinear robust controllers for an air-breathing hypersonic vehicle model. To overcome the analytical intractability of a dynamical model derived from first principles, a simplified control-oriented model is used for control design. The control-oriented model retains most of the features of the original model, including non-minimum phase characteristic of the flight-path angle dynamics and strong couplings between the engine and flight dynamics, whereas flexibility effects, included in the simulation model, are regarded as a dynamic perturbation. In adopting reduced-complexity models for controller design, the issue of robustness with respect to model uncertainty must be carefully addressed and included at the design level. Dynamic inversion-based design methods do not lend themselves easily to quantitative robustness analysis, due to the complexity of the inverse model of the plant. In this work, a nonlinear sequential loop-closure approach is adopted to design two different dynamic state-feedback controllers that provide stable tracking of velocity and altitude reference trajectories. The approach considered utilizes a combination of adaptive and robust design methods based on both classical and recently developed nonlinear design tools. Simulation results indicate that the proposed methodology may constitute a feasible approach towards the development of robust nonlinear controllers that satisfactorily address the issue of model uncertainty for this type of application.
Book Synopsis Hypersonic Vehicle Control Law Development Using H Infinity and Mu-synthesis by :
Download or read book Hypersonic Vehicle Control Law Development Using H Infinity and Mu-synthesis written by and published by . This book was released on 1992 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Adaptive Control of Hypersonic Vehicles in Presence of Actuation Uncertainties by : Amith Somanath
Download or read book Adaptive Control of Hypersonic Vehicles in Presence of Actuation Uncertainties written by Amith Somanath and published by . This book was released on 2010 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: The thesis develops a new class of adaptive controllers that guarantee global stability in presence of actuation uncertainties. Actuation uncertainties culminate to linear plants with a partially known input matrix B. Currently available multivariable adaptive controllers yield global stability only when the input matrix B is completely known. It is shown in this work that when additional information regarding the structure of B is available, this difficulty can be overcome using the proposed class of controllers. In addition, a nonlinear damping term is added to the adaptive law to further improve the stability characteristics. It is shown here that the adaptive controllers developed above are well suited for command tracking in hypersonic vehicles (HSV) in the presence of aerodynamic and center of gravity (CG) uncertainties. A model that accurately captures the effect of CG shifts on the longitudinal dynamics of the HSV is derived from first principles. Linearization of these nonlinear equations about an operating point indicate that a constant gain controller does not guarantee vehicle stability, thereby motivating the use of an adaptive controller. Performance improvements are shown using simulation studies carried out on a full scale nonlinear model of the HSV. It is shown that the tolerable CG shifts can be almost doubled by using an adaptive controller as compared to a linear controller while tracking reference commands in velocity and altitude.
Book Synopsis Reference Command Tracking for a Linearized Model of an Air-Breathing Hypersonic Vehicle by :
Download or read book Reference Command Tracking for a Linearized Model of an Air-Breathing Hypersonic 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: The focus of this paper is on control design and simulation for an air-breathing hypersonic vehicle. The challenges for control design in this class of vehicles lie in the inherent coupling between the propulsion system, and the airframe dynamics, and the presence of strong flexibility effects. Working from a highly nonlinear, dynamically-coupled simulation model, control designs are presented for velocity, angle-of-attack, and altitude command input tracking for a linearized version of a generic air-breathing hypersonic vehicle model linearized about a specific trim condition. Control inputs for this study include elevator deflection, total temperature change across the combustor, and the diffuser area ratio. Two control design methods are presented, both using linear quadratic techniques with integral augmentation, and are implemented in tracking control studies. The first approach focuses on set point tracking control, whereas in the second, a regulator design approach is taken. The effectiveness of each control design is demonstrated in simulation on the full nonlinear model of the generic vehicle.
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781720359456 Total Pages :32 pages Book Rating :4.3/5 (594 download)
Book Synopsis A Generic Inner-Loop Control Law Structure for Six-Degree-Of-Freedom Conceptual Aircraft Design by : National Aeronautics and Space Administration (NASA)
Download or read book A Generic Inner-Loop Control Law Structure for Six-Degree-Of-Freedom Conceptual Aircraft Design written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-29 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: A generic control system framework for both real-time and batch six-degree-of-freedom simulations is presented. This framework uses a simplified dynamic inversion technique to allow for stabilization and control of any type of aircraft at the pilot interface level. The simulation, designed primarily for the real-time simulation environment, also can be run in a batch mode through a simple guidance interface. Direct vehicle-state acceleration feedback is required with the simplified dynamic inversion technique. The estimation of surface effectiveness within real-time simulation timing constraints also is required. The generic framework provides easily modifiable control variables, allowing flexibility in the variables that the pilot commands. A direct control allocation scheme is used to command aircraft effectors. Primary uses for this system include conceptual and preliminary design of aircraft, when vehicle models are rapidly changing and knowledge of vehicle six-degree-of-freedom performance is required. A simulated airbreathing hypersonic vehicle and simulated high-performance fighter aircraft are used to demonstrate the flexibility and utility of the control system.Cox, Timothy H. and Cotting, M. ChristopherArmstrong Flight Research CenterAIRCRAFT DESIGN; DEGREES OF FREEDOM; CONTROL SYSTEMS DESIGN; ALGORITHMS; AIRCRAFT PERFORMANCE; COMPUTERIZED SIMULATION; HYPERSONIC VEHICLES; STABILITY; CONTROL SURFACES; REAL TIME OPERATION; CONTROLLABILITY
Book Synopsis Certifiable L1 Adaptive Control for Helicopters by : Magnus Bichlmeier
Download or read book Certifiable L1 Adaptive Control for Helicopters written by Magnus Bichlmeier and published by Cuvillier Verlag. This book was released on 2016-06-27 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Hubschraubern kommen mitunter aufwändige regelungstechnische Verfahren zum Einsatz, um ein intuitiv steuerbares und stabiles Verhalten der Maschine zu erzeugen. Klassische Ansätze in der Entwicklung setzen dabei auf Iterationen aus Systemidentifikation und Auslegung des Systems im Frequenzbereich. In diesem Buch wird vor dem Hintergrund der nur zu gerne unterschätzten Problematik der begrenzten Bandbreiten eine robuste adaptive Regelung eingeführt. Dazu wird ein hochfrequent-aktualisierender L1-adaptiver Regler entsprechend angepasst, ein neues adaptives Gesetz der Ausgangsrückführung eingeführt, eine neue Strategie zur Auslegung der Zustandsrückführung vorgestellt, und für den sicherheitskritischen Aspekt Effekte von Ungenauigkeiten im Rechentakt und von Sensorrauschen evaluiert. Während klassische Ansätze durch nichtlineare Optimierung weitestgehend automatisierbar sind und dennoch die Notwendigkeit wiederholter Flugtests nicht verhindern können, ist der L1-adaptive Regler bei entsprechendem Systemverständnis besonders geeignet, Entwicklungszeiten zu verkürzen. Strenge mathematische Beweise untermauern die Stabilität und Robustheit der eingeführten Algorithmen, wobei die Flugeigenschaften in einem Forschungssimulator verifiziert werden. Often, very complex controller techniques are applied to helicopters for generating an intuitively controllable and stable behavior of the aircraft. In legacy controllers, a number of iterations of system identification and loop shaping methods in frequency domain have to be conducted. In this book, a robust adaptive control theory is introduced, with the often underestimated fact of only limited available bandwidths in mind. To this end, the high-frequency adapting L1-adaptive controller is adjusted, a new adaptive law for output feedback is introduced, a new strategy for defining the design of a state feedback controller is proposed, and effects of uncertainties in the processor clock rate and of sensor noise are evaluated for taking the safety critical nature of the system into account. While legacy approaches can be automated by nonlinear optimization techniques and yet cannot eliminate the necessity of repeated flight tests, the L1-adaptive controller is particularly suitable to reduce development time, provided a sufficiently deep understanding of the system is available. Rigorous mathematical proofs substantiate the stability and robustness of the algorithms as shown, while performance and handling qualities are verified in a research simulator.
Book Synopsis L1 Adaptive Control Theory by : Naira Hovakimyan
Download or read book L1 Adaptive Control Theory written by Naira Hovakimyan and published by SIAM. This book was released on 2010-09-30 with total page 333 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contains results not yet published in technical journals and conference proceedings.
Book Synopsis Steady Glide Dynamics and Guidance of Hypersonic Vehicle by : Wanchun Chen
Download or read book Steady Glide Dynamics and Guidance of Hypersonic Vehicle written by Wanchun Chen and published by Springer Nature. This book was released on 2020-11-07 with total page 461 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the latest researches on hypersonic steady glide dynamics and guidance, including the concept of steady glide reentry trajectory and the stability of its regular perturbation solutions, trajectory damping control technique for hypersonic glide reentry, singular perturbation guidance of hypersonic glide reentry, trajectory optimization based on steady glide, linear pseudospectral generalized nominal effort miss distance guidance, analytical entry guidance and trajectory-shaping guidance with final speed and load factor constraints. They can be used to solve many new difficult problems in entry guidance. And many practical engineering cases are provided for the readers for better understanding. Researchers and students in the fields of flight vehicle design or flight dynamics, guidance and control could use the book as valuable reference.
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781722605780 Total Pages :66 pages Book Rating :4.6/5 (57 download)
Book Synopsis Investigation of Piloting Aids for Manual Control of Hypersonic Maneuvers by : National Aeronautics and Space Administration (NASA)
Download or read book Investigation of Piloting Aids for Manual Control of Hypersonic Maneuvers written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-08 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation of piloting aids designed to provide precise maneuver control for an air-breathing hypersonic vehicle is described. Stringent constraints and nonintuitive high-speed flight effects associated with maneuvering in the hypersonic regime raise the question of whether manual control of such a vehicle should even be considered. The objectives of this research were to determine the extent of manual control that is desirable for a vehicle maneuvering in this regime and to identify the form of aids that must be supplied to the pilot to make such control feasible. A piloted real-time motion-based simulation of a hypersonic vehicle concept was used for this study, and the investigation focused on a single representative cruise turn maneuver. Piloting aids, which consisted of an auto throttle, throttle director, autopilot, flight director, and two head-up display configurations, were developed and evaluated. Two longitudinal control response types consisting of a rate-command/attitude-hold system and a load factor-rate/load-factor-hold system were also compared. The complete set of piloting aids, which consisted of the autothrottle, throttle director, and flight director, improved the average Cooper-Harper flying qualities ratings from 8 to 2.6, even though identical inner-loop stability and control augmentation was provided in all cases. The flight director was determined to be the most critical of these aids, and the cruise turn maneuver was unachievable to adequate performance specifications in the absence of this flight director. Raney, David L. and Phillips, Michael R. and Person, Lee H., Jr. Langley Research Center...
Book Synopsis Adaptive Control of Hypersonic Vehicles by : Travis Eli Gibson
Download or read book Adaptive Control of Hypersonic Vehicles written by Travis Eli Gibson and published by . This book was released on 2008 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: The guidance, navigation and control of hypersonic vehicles are highly challenging tasks due to the fact that the dynamics of the airframe, propulsion system and structure are integrated and highly interactive. Such a coupling makes it difficult to model various components with a requisite degree of accuracy. This in turn makes various control tasks including altitude and velocity command tracking in the cruise phase of the flight extremely difficult. This work proposes an adaptive controller for a hypersonic cruise vehicle subject to: aerodynamic uncertainties, center-of-gravity movements, actuator saturation, failures, and time-delays. The adaptive control architecture is based on a linearized model of the underlying rigid body dynamics and explicitly accommodates for all uncertainties. Within the control structure is a baseline Proportional Integral Filter commonly used in optimal control designs. The control design is validated using a highfidelity HSV model that incorporates various effects including coupling between structural modes and aerodynamics, and thrust pitch coupling. Analysis of the Adaptive Robust Controller for Hypersonic Vehicles (ARCH) is carried out using a control verification methodology. This methodology illustrates the resilience of the controller to the uncertainties mentioned above for a set of closed-loop requirements that prevent excessive structural loading, poor tracking performance, and engine stalls. This analysis enables the quantification of the improvements that result from using and adaptive controller for a typical maneuver in the V-h space under cruise conditions.
Book Synopsis Output Feedback Control and Sensor Placement for a Hypersonic Vehicle Model by : Pete Jankovsky
Download or read book Output Feedback Control and Sensor Placement for a Hypersonic Vehicle Model written by Pete Jankovsky and published by . This book was released on 2006 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper addresses issues related to output feedback control, including sensor placement, for a model of an air-breathing hypersonic vehicle. The model presents a number of control challenges, in particular because of strong couplings between the propulsive and aerodynamic forces. Because of the vehicle's low weight, slenderness, and length, the vehicle's flexibility has a large impact on stability and control of the vehicle. Two output feedback control methods are developed. One applies reconstruction of the flexible body system states, toward applications of state feedback control. The other uses a robust design that does not rely on an observer to ensure stabilization and performance throughout a given flight envelope. A rate gyroscope and an accelerometer have been modeled, incorporating the flexible effects, and strategies for sensor placement have been developed for the hypersonic vehicle model to enhance observability or to preserve certain system structures that are favorable for robust control design. Simulation results are provided to demonstrate the sensor placement strategies and output feedback control performances.
Book Synopsis Applications of Adaptive Control by : Kumpati S. Narendra
Download or read book Applications of Adaptive Control written by Kumpati S. Narendra and published by . This book was released on 1980 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt:
