抄録
In digital control system driven by relay element, dead time existing in process dynamic characteristics seriously affects the stability of the system. In this paper, Equation (6) showing the relation between loop gain and dead time is obtained to make stable the secondary system shown in Fig. 3 by phase plane approach. In order to keep the system stable, however, loop gain must be considerably small and from this reason, the response will be much delayed. In digital control systems, it is desirable to compensate this dead time by logical operations only. Therefore, a simple nonlinear compensator, which is mainly composed of comparators shown in Fig. 14, is introduced by measuring the incremental pulse duration. An illustrative example shows that this compensator considerably shortens the response time to the step input.
