Approximate Calculation of the Hunting of Relay Servomechanism Operating on Sampled Data : The Case of Three-Position Relay

Abstract

In the preceding paper, we treated a relay servomechanism operating on two-position relays with and without hysteresis. In this paper, we treated the hunting of a three-position relay without hysteresis using the describing function and showed that the result of this analysis is in very good agreement with that of the experiment. When such a relay is used, the following conditions are necessary for the system to enter the dead zone without hunting. (1) The relay has a wide dead zone. (2) The control system has a small gain. (3) The sampling period is small.