Download or read book Hypersonic Flight Control System Design Using Fixed Order Robust Controllers written by Harald Buschek and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Research in Robust Control for Hypersonic Aircraft written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-11 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research during the third reporting period focused on fixed order robust control design for hypersonic vehicles. A new technique was developed to synthesize fixed order H(sub infinity) controllers. A controller canonical form is imposed on the compensator structure and a homotopy algorithm is employed to perform the controller design. Various reduced order controllers are designed for a simplified version of the hypersonic vehicle model used in our previous studies to demonstrate the capabilities of the code. However, further work is needed to investigate the issue of numerical ill-conditioning for large order systems and to make the numerical approach more reliable. Calise, A. J. Unspecified Center NAG1-1451...

Download or read book Robust Nonlinear Control System Design for Hypersonic Flight Vehicles written by Obaid Ur Rehman and published by . This book was released on 2011 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis develops a new nonlinear robust control design procedure which addresses some of the challenges associated with the control of uncertain nonlinear system and applies the proposed method to tracking control of an Air-breathing Hypersonic Flight Vehicle (AHFV). The AHFV is a highly nonlinear system and the combination of nonlinear dynamics, parameter uncertainty and complex constraints make the flight control design a challenging task for this type of vehicle. The main contribution of this thesis lies in the fact that it presents a robust feedback linerization based strategy which solves the control issue of a class of nonlinear systems subject to parametric uncertainty. The method is effectively applied to the tracking control of an AHFV. It is also demonstrated that the proposed approach can be used to design a single robust controller for a large flight envelope rather than using several gain scheduled controllers. This research, firstly presents three different approaches to develop linearized uncertainty models for a class of nonlinear systems using a robust feedback lnearization method. The feedback linearization approach to linearize the nonlinear dynamics has some advantages over the point linearization (Jacobian linearization) method. However, the feedback linearization method only linearizes the nominal model of a system and in the presence of uncertainty in the model the exact linearization is not possible. In this thesis, we present a robust approach to deal with the nonlinearities arising from the uncertainties in the system and use a nonlinear AHFV model to demonstrate the effectiveness of the method. Besides parametric uncertainty, due to the presence of body-integrated propulsion system, and the flexible modes, the nonlinear model of AHFV does not possess full relative degree. Any attempt to feedback linearize this nonlinear model will result into having input term in low order derivatives of the system output. In this research, we strategically remove the coupling and flexible effects from the nonlinear model and simplify the model in such a way that the full relative degree condition is satisfied. In the development of linearized uncertainty model for an AHFV the conventional feedback linearization approach is used to remove the known nonlinearities from the simplified system model and the nonlinearities arising from the uncertainties are treated in three different ways. In the first method, nonlinear uncertainties are linearized using Taylor expansion at an arbitrary point by considering a structured representation of uncertainties. This lienarization approach approximates the actual nonlinear uncertainty by considering only the first order terms and neglecting all the higher order terms. For the linearized model, a minimax Linear Quadratic Regulator (LQR) controller combined with feedback linearization law is proposed to fulfill the velocity and altitude tracking requirements of an AHFV. In the second method, an unstructured uncertainty representation is considered and a minimax Linear Quadratic Gaussian (LQG) controller combined with feedback linearization law is proposed for the same tracking requirements. In the third, method the nonlinear uncertainty terms are linearized at an arbitrary point using the generalized mean value theorem. The main advantages of using this approach are that upper bound on the uncertainties can be obtained by both structured and unstructured uncertainty representations and there is no need to ignore higher order uncertainty terms. The uncertain linearized models obtained from this method are followed by guaranteed cost and minimax LQR controllers combined with feedback linearization law. Rigorous simulations using actual nonlinear model for all the above methods are presented in the thesis to analyze the effectiveness of these controllers. These simulations have considered several cases of uncertainties for a step change in the reference commands. In order to see the robustness properties of the proposed robust scheme a Monte-Calro based simulation is also presented by considering the given bound on the uncertain parameters. Also, in order to demonstrate the effectiveness of the approach for a large flight envelope, several simulations are performed to observe the tracking response for the given reference trajectories in a large flight envelope.

Download or read book Evolutionary Design of Robust Flight Control for a Hypersonic Aircraft written by Kevin J. Austin and published by . This book was released on 2002 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Robust Discrete Time Flight Control of UAV with External Disturbances written by Shuyi Shao and published by Springer Nature. This book was released on 2020-09-26 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book studies selected discrete-time flight control schemes for fixed-wing unmanned aerial vehicle (UAV) systems in the presence of system uncertainties, external disturbances and input saturation. The main contributions of this book for UAV systems are as follows: (i) the proposed integer-order discrete-time control schemes are based on the designed discrete-time disturbance observers (DTDOs) and the neural network (NN); and (ii) the fractional-order discrete-time control schemes are developed by using the fractional-order calculus theory, the NN and the DTDOs. The book offers readers a good understanding of how to establish discrete-time tracking control schemes for fixed-wing UAV systems subject to system uncertainties, external wind disturbances and input saturation. It represents a valuable reference guide for academic research on uncertain UAV systems, and can also support advanced / Ph.D. studies on control theory and engineering.

Download or read book Handbook of Learning and Approximate Dynamic Programming written by Jennie Si and published by John Wiley & Sons. This book was released on 2004-08-02 with total page 670 pages. Available in PDF, EPUB and Kindle. Book excerpt: A complete resource to Approximate Dynamic Programming (ADP), including on-line simulation code Provides a tutorial that readers can use to start implementing the learning algorithms provided in the book Includes ideas, directions, and recent results on current research issues and addresses applications where ADP has been successfully implemented The contributors are leading researchers in the field

Download or read book AIAA Sixth International Aerospace Planes and Hypersonics Technologies Conference 95 6050 95 6099 written by and published by . This book was released on 1995 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book Disturbance Observer Based Control written by Shihua Li and published by CRC Press. This book was released on 2016-04-19 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to its abilities to compensate disturbances and uncertainties, disturbance observer based control (DOBC) is regarded as one of the most promising approaches for disturbance-attenuation. One of the first books on DOBC, Disturbance Observer Based Control: Methods and Applications presents novel theory results as well as best practices for applica

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1998 with total page 980 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Autonomous Safety Control of Flight Vehicles written by Xiang Yu and published by CRC Press. This book was released on 2021-02-12 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerospace vehicles are by their very nature a crucial environment for safety-critical systems. By virtue of an effective safety control system, the aerospace vehicle can maintain high performance despite the risk of component malfunction and multiple disturbances, thereby enhancing aircraft safety and the probability of success for a mission. Autonomous Safety Control of Flight Vehicles presents a systematic methodology for improving the safety of aerospace vehicles in the face of the following occurrences: a loss of control effectiveness of actuators and control surface impairments; the disturbance of observer-based control against multiple disturbances; actuator faults and model uncertainties in hypersonic gliding vehicles; and faults arising from actuator faults and sensor faults. Several fundamental issues related to safety are explicitly analyzed according to aerospace engineering system characteristics; while focusing on these safety issues, the safety control design problems of aircraft are studied and elaborated on in detail using systematic design methods. The research results illustrate the superiority of the safety control approaches put forward. The expected reader group for this book includes undergraduate and graduate students but also industry practitioners and researchers. About the Authors: Xiang Yu is a Professor with the School of Automation Science and Electrical Engineering, Beihang University, Beijing, China. His research interests include safety control of aerospace engineering systems, guidance, navigation, and control of unmanned aerial vehicles. Lei Guo, appointed as "Chang Jiang Scholar Chair Professor", is a Professor with the School of Automation Science and Electrical Engineering, Beihang University, Beijing, China. His research interests include anti-disturbance control and filtering, stochastic control, and fault detection with their applications to aerospace systems. Youmin Zhang is a Professor in the Department of Mechanical, Industrial and Aerospace Engineering, Concordia University, Montreal, Québec, Canada. His research interests include fault diagnosis and fault-tolerant control, and cooperative guidance, navigation, and control (GNC) of unmanned aerial/space/ground/surface vehicles. Jin Jiang is a Professor in the Department of Electrical & Computer Engineering, Western University, London, Ontario, Canada. His research interests include fault-tolerant control of safety-critical systems, advanced control of power plants containing non-traditional energy resources, and instrumentation and control for nuclear power plants.

Download or read book Modeling and Nonlinear Control of a 6 DOF Hypersonic Vehicle written by Mohammad Shakiba-Herfeh and published by . This book was released on 2015 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past two decades, there has been a renewed and sustained effort devoted to modeling the dynamics of air-breathing hypersonic vehicles, for both simulation and control design purposes. The highly nonlinear characteristics of flight dynamics in hypersonic regimes and the consequent significance variability of the response with the operating conditions requires the development of innovative flight control solutions, hence the development of suitable model of the vehicle dynamics that are amenable to design, validation and rapid calibration of control algorithms. In this dissertation, a control-oriented and a simulation model of a generic hypersonic vehicle were derived to support the design and calibration of model-based flight controllers. A nonlinear robust adaptive controller was developed on the basis of the control-oriented model, that was shown to provide stable trajectory tracking in higher fidelity computer simulations. The first stage of this research was the development of a control design model (CDM) for the 6-degree-of-freedom dynamics of an air-breathing hypersonic aircraft based on an available high-fidelity first principle model. A method that incorporates the theory of compressible fluid dynamics and system identification methods, was proposed and implemented. The development of the CDM is based on curve fit approximation of the forces and moments acting on the vehicle, making the model suitable for control design. Kriging and Least Squares methods were used to find the most appropriate curve-fitted model of the aerodynamic forces for both the control design and the control simulation models. It was shown that the 6-DOF model can be both categorized as an under-actuated mechanical system, as well as an over-actuated system with respect to a chosen in- put/output pair of interest. An important contribution of this work is the development of a nonlinear adaptive controller for the 6-DOF control design model. The controller was endowed with a modular structure, comprised of an adaptive inner-loop attitude controller and a robust nonlinear outer-loop controller of fixed structure. The purpose of the outer- loop controller is to avoid the typical complexity of solutions derived from adaptive backstepping methods. A noticeable feature of the outer-loop controller is the presence of an internal model unit that generates the reference for the angle-of-attack, in spite of parametric model uncertainty. Airspeed, lateral velocity, vehicle's heading and altitude were considered as regulated outputs of the system. Simulation results on the control simulation model show the effectiveness of the developed controller in spite of significant variation in the flight parameters.

Download or read book Robust Intelligent Flight Control for Hypersonic Vehicles written by Gregory Errol Chamitoff and published by . This book was released on 1992 with total page 664 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modelling and Control of Hypersonic Aircraft Vehicles written by Barış Bıdıklı and published by . This book was released on 2012 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: The increasing number of works on hypersonics and the recent interest of Ministry of Defense on developing a hypersonic missile are amongst the main motivations behind this thesis. Research on hypersonics seems to divide into two main categories: deriving dynamic models for HSVs and designing model-based controllers. Initially, we decided to investigate the control problems associated with HSVs. However, due to the restrictions imposed by the leading sponsors of hypersonic research (such as NASA, US AF, US DoD, DARPA, etc), researchers did neither publish nor share the model parameters for HSVs. As a result, our initial focus was deriving a dynamic model for an HSV. Firstly, modelling approaches for HSVs and we noticed that it is extremely hard to directly obtain the HSV dynamic model parameters. In addition to this, the HSV nonlinear dynamic model which was commonly mentioned in the literature is not related to the control inputs directly. As a result, the linearized HSV dynamic models were investigated, and the linear parameter varying model was derived. Next, control problems associated with the HSVs are investigated. Due to the highly complicated and time-varying nature of their dynamics, designing a robust control law is aimed. The main reason behind choosing to design a robust control law was that the robust controllers usually require minimum knowledge about the HSV dynamics. The stability of the proposed robust control law is then investigated via Lyapunov-based techniques and the tracking error is driven to the origin exponentially fast by using designed controller.

Download or read book Flight Stability and Automatic Control written by Robert C. Nelson and published by WCB/McGraw-Hill. This book was released on 1998 with total page 441 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of Flight Stability and Automatic Control presents an organized introduction to the useful and relevant topics necessary for a flight stability and controls course. Not only is this text presented at the appropriate mathematical level, it also features standard terminology and nomenclature, along with expanded coverage of classical control theory, autopilot designs, and modern control theory. Through the use of extensive examples, problems, and historical notes, author Robert Nelson develops a concise and vital text for aircraft flight stability and control or flight dynamics courses.