DocumentCode :
861264
Title :
Feedback system testing
Author :
White, Connor
Author_Institution :
Naval Research Laboratory, Washington DC, USA
Volume :
6
Issue :
1
fYear :
1958
fDate :
12/1/1958 12:00:00 AM
Firstpage :
79
Lastpage :
88
Abstract :
An analog method of servo system performance testing applicable to experimental analysis and system development and to go-no-go production and maintenance tesfiug has been devised. For a servo system with a forward transfer function Geoand a feedback transfer function Gouthe loop actuating signal equals the loop input signal divided by 1+G_{eo}G_{ou} . The loop actuating signal becomes exactly equal to a test signal if the test signal is multiplied by the factor 1+G_{eo}G_{ou} before application to the servo system. The difference between the loop actuating signal of the closed-loop servo system and the arbitrary test signal is continuously zero for the system exactly meeting the specification G_{eo}G_{ou} function simulated in the signal generator. Sinusoidal testing methods are most effective with the servo system loop open. Transient testing (single-event time-domain input) is usually performed on servo systems with the loop closed. The analog method described, as distinguished from transient and sinusoidal methods, uses time-domain signals (a step-function signal generator input is found suitable) to obtain frequency-domain parameters in a method effectively making an open-loop test of a closed-loop servo system. The 1+G_{eo}G_{ou} signal generator is conveniently realized using an analog computer of the operational amplifier type. An alternative mechanization of the signal generator uses only passive elements. Nonlinear as well as linear servo systems may be tested by the method. Single-integrator, angle tracking, and range-tracking servo systems have been analyzed. The range-tracking transfer function was employed in an analog computer experiment. Recordings of both the loop actuating signal and the difference between the loop actuating signal and the signal generator input were made for 0, ± 6 db, and ± 12 db departures from correct gain and for 0, ± 1, and ± 2 octave departures from correct corner frequency. A study of these recordings revealed potentialities for control of adaptive servo systems.
Keywords :
Analog computers; Feedback; Performance analysis; Production systems; Servomechanisms; Signal generators; System performance; System testing; Time domain analysis; Transfer functions;
fLanguage :
English
Journal_Title :
Automatic Control, IRE Transactions on
Publisher :
ieee
ISSN :
0096-199X
Type :
jour
DOI :
10.1109/TAC.1958.1105176
Filename :
1105176
Link To Document :
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