Discrete-time HIGS based digital control of negative imaginary systems

Abstract

A hybrid integrator-gain system (HIGS) is a control element that switches between an integrator and a gain. This overcomes some inherent limitations of linear controllers. In this paper, we consider using discrete-time HIGS controllers for the digital control of negative imaginary (NI) systems. We show that discrete-time HIGS are step-advanced negative imaginary systems. For a minimal linear NI system, an asymptotically stabilizing HIGS controller always exists. A hardware experiment was carried out in which a flexure-guided nanopositioner, as an example of a linear NI system, was effectively damped using the proposed discrete-time HIGS method. Show more