# Aircraft Dynamics and Automatic Control

DUANE McRUER
IRVING ASHKENAS
DUNSTAN GRAHAM
Pages: 808
https://www.jstor.org/stable/j.ctt7ztqhj

1. Front Matter
(pp. iii-iv)
2. PREFACE
(pp. v-viii)
Duane McRuer, Irving Ashkenas and Dunstan Graham
(pp. ix-xii)
4. LIST OF FIGURES
(pp. xiii-xxii)
5. LIST OF TABLES
(pp. xxiii-2)
6. CHAPTER 1 INTRODUCTION AND ANTECEDENTS
(pp. 3-50)

The economic or military value of any vehicle depends fundamentally on its ability to traverse a controllable path between its point of departure and its destination or “target.” Abstractly, the vehicle is a velocity vector in space. It has a direction in which it is going and a speed with which it is going there. The time integral of the velocity vector is the path. Each type of vehicle, however, is made to move and carry in a certain medium and its motions may be subject to constraints. Means for the control of the path vary widely and depend on...

7. CHAPTER 2 MATHEMATICAL MODELS OF LINEARS SYSTEM ELEMENTS
(pp. 51-109)

A major task in systems analysis is the estimation of system response to commands or disturbances. The most concrete way to determine behavior is to test the actual system. This direct experimental approach is precluded in the early phases of design, when the “system” may be but one of a number of competing possibilities, or when the physical system may be unavailable. Fortunately, many of the potential results of actual physical measurements can be foreseen by performing experiments utilizing various models of the system.

As the underlying basis for system models consider the block diagram representation of Fig. 2.1. The...

8. CHAPTER 3 FEEDBACK SYSTEM ANALYSIS
(pp. 110-202)

The early development of automatic flight controls evolved substantially independently of the use of any mathematics. By 1947, however, it was widely recognized that the dynamic problems of vehicle control could not be mastered by cut-and-try techniques or engineers’ rules of thumb. To fill this need, the elaborate and extensive theory of linear feedback systems was further developed and then applied to an increasingly wide range of flight control problems. There was a dramatic interplay between theory and practice where, in many cases, aircraft and missiles provided both the inspiration for the theoretical developments and the examples of practical application....

9. CHAPTER 4 VEHICLE EQUATIONS OF MOTION
(pp. 203-295)

With our background in feedback control and analysis methods established in the preceding chapters, we come now to the object of such control—the vehicle. We want to characterize the vehicle in a way that is especially instructive to the flight control system designer, rather than to the stability and control aerodynamicist or dynamic specialist. In order to do this, we deliberately emphasize the vehicle dynamic properties as a whole, not the sum of its component parts. For example, we avoid the finegrain details of stability derivatives and their dependence on configuration layout, in favor of a rudimentary understanding of...

10. CHAPTER 5 LONGITUDINAL DYNAMICS
(pp. 296-352)

The vehicle dynamic properties, defined in general by the equations of motion derived in the last chapter, are best specified for use in control system analysis by a series of transfer functions that relate output quantities (various airframe motions) to input variables (usually control motions or external disturbances). These transfer functions are readily obtained from the linearized Laplace-transformed airframe equations of motion as sets of ratios between transformed airframe output and input quantities or initial conditions. The ratios comprise numerators and denominators expressed as rational polynomials in the Laplace transform variable, s. The various polynomial coefficients are composed of combinations...

11. CHAPTER 6 LATERAL DYNAMICS
(pp. 353-418)

The treatment of the vehicle’s lateral dynamic properties given in this chapter closely follows the form and content of the preceding chapter on longitudinal dynamics. The first article in this chapter recapitulates the lateral equations of motion as commonly used, presents the polynomial forms of the more important control-input transfer functions, and develops an appreciation for the transfer functions and responses with numerical examples. Based on the physical insights thus afforded, we then develop further-simplified sets of equations that apply to the individual modes of motion appropriate for conventional aircraft; this is followed by similar considerations of VTOL aircraft in...

12. CHAPTER 7 ELEMENTARY LONGITUDINAL FEEDBACK CONTROL
(pp. 419-457)

A most powerful approach to obtain an appreciation for the effects of automatic control on the motions of an aircraft is to consider closed-loop systems formed by direct feedback of aircraft motion quantities to the controls. Such systems are idealizations since, in fact, the controls cannot be moved without lag, and instruments cannot sense and reproduce the motion quantities instantaneously and in a pure form. Nevertheless, consideration of these idealized systems shows the ultimate performance approachable by some practical system or, by way of contrast, reveals directions in which it would be unprofitable to proceed.

The prototype for all the...

13. CHAPTER 8 ELEMENTARY LATERAL FEEDBACK CONTROL
(pp. 458-490)

The usefulness of studying feedback loops closed around the various transfer functions of aircraft is exactly the same in the case of lateral motions as it is for longitudinal. Idealized systems still serve to show the ultimate performance that practical systems can approach or, on the other hand, tend to show which feedbacks are unlikely to prove useful.

A general block diagram for the cases of lateral motion quantity feed back is identical to the one for longitudinal motion quantity feedback (see Fig. 7-1). Again it will be sufficient, in most instances, to consider that the controller is simply a...

14. CHAPTER 9 REQUIREMENTS, SPECIFICATIONS, AND TESTING
(pp. 491-536)

In Chapter 1 there was occasion to suggest the importance of feedback to the solution of the problem of control and guidance of aeronautical vehicles. In particular, its roles in making the vehicle amenable to following guidance commands and in suppressing the effects of disturbances were emphasized. Since then the text has exposed the mathematical and physical principles necessary to the solution of the deterministicanalysisproblem, i.e., given the (deterministic) input and the mathematical description of the system, find the outputs or errors. This, however, by no means represents a solution to the design or synthesis problem, i.e., given...

15. CHAPTER 10 INPUTS AND SYSTEM PERFORMANCE ASSESSMENT
(pp. 537-599)

The elementary feedback control system concepts reviewed in the last chapter provide a basis for the view that flight control system performance requirements, in the large, serve to define a system that will follow desired inputs, reject internal disturbances, and suppress external disturbances. There remain the inevitable questions of how well the “following,” “rejecting,” and “suppressing” needs to be done; and what the tradeoffs may be between the design qualities of reliability, weight, power demands, cost, etc., and the dynamic performance quantities of following, rejecting, and suppressing. Further, in flight control systems the controlled element (vehicle) is not entirely unalterable,...

16. CHAPTER 11 MULTILOOP FLIGHT CONTROL SYSTEMS
(pp. 600-684)

According to one system of Chinese philosophy, the cycles of affairs in the circumscribed area of the terrestrial globe can be accounted for by the alternating influence of the counterpoised forcesyinandyang.The development of the material so far presented here has perhaps afforded the occasion to observe such cycles and indeed cycles on the cycles. We now wish to complete the last circumvolution by demonstrating the mathematical synthesis of multiloop automatic flight control to meet requirements. In this chapter, we complete the system and circumscribe our subject. We limit the subject by bringing the discussion to a...

17. APPENDIX A STABILITY DERIVATIVES AND TRANSFER FUNCTION FACTORS FOR REPRESENTATIVE AIRCRAFT
(pp. 687-743)
18. APPENDIX B ELEMENTS OF PROBABILITY
(pp. 744-768)
19. BIBLIOGRAPHY
(pp. 769-774)
20. INDEX
(pp. 775-784)