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Book Design of a Multivariable Helicopter Flight Control System for Handling Qualities Enhancement

Download or read book Design of a Multivariable Helicopter Flight Control System for Handling Qualities Enhancement written by and published by . This book was released on 1990 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: New handling qualities specifications are currently being developed for attack helicopters. Most unaugmented helicopters will not meet these specifications and feedback control is necessary to improve handling qualities so that safe operation close to the earth in poor weather conditions and/or at night is possible. In this paper a methodology for the direct design of helicopter flight control systems which meet handling qualities specifications is presented. This methodology uses full state feedback to place closed loop eigenvalues to achieve bandwidth specifications and to shape closed loop eigenvectors to decouple lateral and longitudinal responses to control inputs. Full state feedback requires that all state variables be known; however, only angular rates and normal acceleration are measured by sensors. Thus, a state estimator is required in the feedback loop in order to convert sensor outputs to control inputs. This estimator is designed using eigenstructure assignment so as to achieve loop transfer recovery. Design of a feedback system for use in precise hovering control for a modern attack helicopter is used to illustrate the method. Control law synthesis is accomplished using an eighth order model which includes only rigid body modes. Control law performance is evaluated using a 37th order model which includes rigid body, actuator, rotor, sensor, and flexure dynamics. It is found that a notch filter must be added to the design in order to eliminate a high frequency instability. Once this is accomplished, both the time and frequency response characteristics of the augmented helicopter are much improved compared with the unaugmented helicopter.

Book Scientific and Technical Aerospace Reports

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Helicopter Flight Control System Design Using the Linear Quadratic Regulator for Robust Eigenstructure Assignment

Download or read book Helicopter Flight Control System Design Using the Linear Quadratic Regulator for Robust Eigenstructure Assignment written by and published by . This book was released on 1992 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis applied modern, multi-variable control design techniques, via a FORTRAN computer algorithm, to U.S. Army helicopter models in hovering flight conditions. Eigenstructure assignment and Linear Quadratic Regulator (LQR) theory are used to achieve enhanced closed loop performance and stability characteristics with full state feedback. The addition of cross coupling weights to the standard LQR performance index is specifically addressed. A desired eigenstructure is chosen with a goal of reduced pilot workload via performance qualities requirements. Cross coupling weighting is shown to provide greater flexibility in achieving a desired closed loop eigenstructure. While the addition of cross coupling weighting is shown to eliminate stability margin guarantees associated with LQR methods, the modified algorithm can achieve a closer match to a desired eigenstructure than previous versions of the program while maintaining acceptable stability characteristics.

Book Helicopter Flight Control System Design Using the Linear Quadratic Regulator for Robust Eigenstructure Assignment

Download or read book Helicopter Flight Control System Design Using the Linear Quadratic Regulator for Robust Eigenstructure Assignment written by Dempsey D. Solomon (CAPT, USA.) and published by . This book was released on 1992 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Advances In Aircraft Flight Control

Download or read book Advances In Aircraft Flight Control written by M B Tischler and published by CRC Press. This book was released on 1996-06-28 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a single comprehensive resource that reviews many of the current aircraft flight control programmes from the perspective of experienced practitioners directly involved in the projects. Each chapter discusses a specific aircraft flight programme covering the control system design considerations, control law architecture, simulation and analysis, flight test optimization and handling qualities evaluations. The programmes described have widely exploited modern interdisciplinary tools and techniques and the discussions include extensive flight test results. Many important `lessons learned' are included from the experience gained when design methods and requirements were tested and optimized in actual flight demonstration.

Book Aeronautical Engineering

Download or read book Aeronautical Engineering written by and published by . This book was released on 1991 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book American Doctoral Dissertations

Download or read book American Doctoral Dissertations written by and published by . This book was released on 1991 with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book A Modern Control Design Methodology with Application to the CH 47 Helicopter

Download or read book A Modern Control Design Methodology with Application to the CH 47 Helicopter written by Richard D. Holdridge and published by . This book was released on 1985 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: A control system design methodology is developed in this dissertation which produces robust, low-order optimal controllers for multiple-input multiple-output systems. The methodology attempts to focus the strengths of recent 'Modern Control' design algorithms on the problems associated with real control system designs. The methodology is a set of procedures which aids the engineer in creating a realizable controller in either digital or analog form. To demonstrate the usefulness of the methodology, two control augmentation systems (CAS) were designed and flight tested on a CH-47 helicopter at NASA Ames Research Center. The first design was a longitudinal cruise CAS giving the pilot decoupled control of forward velocity and climb rate. This design task demonstrated the low-order controller and robustness features of the methodology. It also demonstrated the use of modern control techniques in designing integral-error controllers. Flight test results are presented. The second controller is a translational velocity command/precision hover hold system. This two mode controller demonstrates the methodology as applied to a more complicated design task which includes control law switching and inner loop/outer loop considerations. Flight test results are also presented. Originator-supplied keywords include: Thesis.

Book Eigenspace Design of Helicopter Flight Control Systems

Download or read book Eigenspace Design of Helicopter Flight Control Systems written by and published by . This book was released on 1990 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: An eigenstructure based design methodology for helicopter flight control systems is developed and evaluated in this report. The report provides a detailed review of the application of multivariable design techniques to helicopter flight control systems, a review of applicable handling quality specifications, a description of the mathematical models used, a presentation of the theory of eigenstructure design, application of the theory to a helicopter design problem, and evaluation of the performance and robustness properties of the resulting control laws.

Book NASA SP

    NASA SP

    Book Details:
  • Author :
  • Publisher :
  • Release : 1992
  • ISBN :
  • Pages : 654 pages

Download or read book NASA SP written by and published by . This book was released on 1992 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Linear and Nonlinear Control of Small Scale Unmanned Helicopters

Download or read book Linear and Nonlinear Control of Small Scale Unmanned Helicopters written by Ioannis A. Raptis and published by Springer Science & Business Media. This book was released on 2010-09-28 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been significant interest for designing flight controllers for small-scale unmanned helicopters. Such helicopters preserve all the physical attributes of their full-scale counterparts, being at the same time more agile and dexterous. This book presents a comprehensive and well justified analysis for designing flight controllers for small-scale unmanned helicopters guarantying flight stability and tracking accuracy. The design of the flight controller is a critical and integral part for developing an autonomous helicopter platform. Helicopters are underactuated, highly nonlinear systems with significant dynamic coupling that needs to be considered and accounted for during controller design and implementation. Most reliable mathematical tools for analysis of control systems relate to modern control theory. Modern control techniques are model-based since the controller architecture depends on the dynamic representation of the system to be controlled. Therefore, the flight controller design problem is tightly connected with the helicopter modeling. This book provides a step-by-step methodology for designing, evaluating and implementing efficient flight controllers for small-scale helicopters. Design issues that are analytically covered include: • An illustrative presentation of both linear and nonlinear models of ordinary differential equations representing the helicopter dynamics. A detailed presentation of the helicopter equations of motion is given for the derivation of both model types. In addition, an insightful presentation of the main rotor's mechanism, aerodynamics and dynamics is also provided. Both model types are of low complexity, physically meaningful and capable of encapsulating the dynamic behavior of a large class of small-scale helicopters. • An illustrative and rigorous derivation of mathematical control algorithms based on both the linear and nonlinear representation of the helicopter dynamics. Flight controller designs guarantee that the tracking objectives of the helicopter's inertial position (or velocity) and heading are achieved. Each controller is carefully constructed by considering the small-scale helicopter's physical flight capabilities. Concepts of advanced stability analysis are used to improve the efficiency and reduce the complexity of the flight control system. Controller designs are derived in both continuous time and discrete time covering discretization issues, which emerge from the implementation of the control algorithm using microprocessors. • Presentation of the most powerful, practical and efficient methods for extracting the helicopter model parameters based on input/output responses, collected by the measurement instruments. This topic is of particular importance for real-life implementation of the control algorithms. This book is suitable for students and researches interested in the development and the mathematical derivation of flight controllers for small-scale helicopters. Background knowledge in modern control is required.

Book International Aerospace Abstracts

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: