Abstract
This paper deals with a new type of nonlinear control device for controlled system with a dead time or a higher-order lag.
The nonlinear control device consists of two parts, one is a conventional PID controlling element which is a cascade combination of a PD and a PI controlling element, and the other is a special phase-lead compensating element connected in parallel with the PD one.
Principle, design, construction and characteristics of the nonlinear control device are described in detail. Taking into account of the influence of the saturation of manipulated variable, the frequency characteristics of the nonlinear control device and the step responses of the control system are studied by use of a digital computer.
As a result of the experiment, it is found that the transient responses for the step change in set point of the system with this nonlinear control device are better than the ones with the optimally set PID controller.
