Automatic Controller Design

Plant identification and controller design based on a phase margin

Abstract

In many applications in control engineering, the parameters of the system required for the controller setting can only be calculated with considerable effort, if at all. In such cases, certain characteristic values of the system are usually determined experimentally in order to derive the parameters of a standard controller with empirically derived formulae. The procedure presented here is based on a method to determine the critical amplification and angular frequency at the stability margin, and the "relay autotuning method". For lines with compensation, a PIDT1 controller is tuned automatically, and for lines without
compensation, a PDT1 controller is automatically tuned for a given phase reserve.