Analogue methods for optimum servomechanism design

Optimum design of servomechanisms based on the criterion of minimizing the integral of squared error for representative inputs has been discussed by Hall,1 Phillips,2 and others. Investigations of related criteria, the mean-square and mean-absolute error for a square-wave input, are described in this paper. Experimental results on simulated second- and third-order servomechanisms check closely with analytical values, and the optimum adjustments obtained in this way coincide with those calculated for step function inputs. Measurement and minimization of mean-absolute error appears particularly promising as an experimental design technique. since standard rectifier-type voltmeters can be used and the resulting optimum responses conform with subjective standards of good response.