Practical and efficient method for fractional-order unstable pole-zero cancellation in linear feedback systems

TL;DR

This paper introduces a practical fractional-order cancellation method for non-minimum phase zeros in linear feedback systems, enhancing stability margins without causing internal instability, thus improving control effectiveness.

Contribution

It proposes a novel fractional-order cancellation technique that increases phase and gain margins while maintaining system stability, addressing limitations of traditional zero cancellation methods.

Findings

Increases phase margin of control systems

Enhances gain margin without internal instability

Facilitates more effective control strategies

Abstract

As a very well-known classical fact, non-minimum phase zeros of the process put some limitations on the performance of the feedback system. The source of these limitations is that such non-minimum phase zeros cannot be cancelled by unstable poles of the controller since such a cancellation leads to internal instability. The aim of this paper is to propose a method for fractional-order cancellation of nonminimum phase zeros of the process and studying its properties. It is specially shown that the proposed cancellation strategy increases the phase and the gain margin without leading to internal instability. Since the systems with higher gain and phase margin are easier to control, the proposed method can be used to arrive at more effective controls.