Accession Number : AD0620597

Title :   VALIDITY OF DESCRIBING-FUNCTION TECHNIQUES FOR THE ANALYSIS OF THIRD-ORDER RELAYOPERATED SERVOMECHANISMS.

Descriptive Note : Master's thesis,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DYNAMIC ANALYSIS AND CONTROL LAB

Personal Author(s) : Meisenholder,Gerald Wayne

Report Date : 20 MAY 1957

Pagination or Media Count : 60

Abstract : The relay-operated servomechanism oscillates at finite amplitudes and frequencies with its input equal to zero. These amplitudes and frequencies can be predicted by a special technique which replaces the relay by a quasilinear model called the describing function. To gain confidence and understanding in this type of technique, an analog computer was used to obtain exact solutions for the system and these were compared to solutions obtained by the describing function technique. In this thesis the solution comparisons are presented in a graphical form along with relay characteristic gain-phase plots, motor load gain-phase plots and an explanation of the describing function technique. Describing function predictions were found to be within ten percent of computer solutions for the great part, however, in the region of incipient oscillation results were consistantly poor. (Author)

Descriptors :   (*SERVOMECHANISMS, MATHEMATICAL ANALYSIS), CONTROL SYSTEMS, FEEDBACK, FUNCTIONS(MATHEMATICS), DIFFERENTIAL EQUATIONS, LINEAR PROGRAMMING, ANALOG COMPUTERS, MECHANICAL ENGINEERING, ELECTRICAL ENGINEERING

Distribution Statement : APPROVED FOR PUBLIC RELEASE