A nonvarying-C* control scheme for aircraft
By: by Edward R. Rang
Contributors: Naval Postgraduate School (U.S.)
Publisher: Naval Postgraduate School
Published: 1969
Place of publication: Monterey, California
Language: eng
Number of pages: 28
Subjects: Airplanes; Control systems; Automatic control; Flight; Handling characteristics
Description: A sum of normal acceleration and pitch rate appears to be the best variable to use to control aircraft in the longitudinal axis. The C*-Criterion specifies that the time response of this quantity called C* must fall in a prescribed envelope for all speeds and altitudes. It is equivalent to requiring the control system to hold the coefficients of a certain equation, which describes the aircraft's short-period motion, fixed. This is done by using feedbacks with variable gains. The gain-changing mechanism is found using gradient techniques. The system was shown to be practical by an analog simulation. It was found to be tolerant of instrument noise, elevator hysteresis, and other complications not accounted in the analytical derivations. The study strongly suggests a modification of the C*-Criterion. It is proposed that the coefficients in the expression of the quantity C* should be representative of the aircraft's parameters rather than have the values currently in use. (Author)
Notes: Title from cover.

"4 June 1969"--Cover.

"NPS-57RJ9061A"--Cover.

DTIC Identifiers: Computerized simulation.

Author(s) key words: Automatic flight controls, adaptive controls, aircraft handling qualities, nonlinear controls.

Includes bibliographical references (p. 20).

"Approved for public release; distribution unlimited"--Cover.

Technical report; 1969.

kmc/kmc 10/13/09.