Mixed ICC/ℋ_∞ control for systems with sensors aging

Abstract

A faulty sensor may lead to degraded system performance, system instability or even a fatal accident. On the other hand, the increasing need for safety and reliability has motivated the development of fault-tolerant control techniques. In this work, the sensor performance degradation due to its aging is modelled by the increment of sensor measurement noise covariance. The main contribution of this paper is the characterisation of the control synthesis conditions using parametrised linear matrix inequalities (PLMIs) for a multi-objective gain-scheduled noisy output-feedback controller that minimises the output cost on ${\mathcal{H}}_2$ performance with satisfactory system stability, ${\mathcal{H}}_{\mathrm{\infty }}$ performance and control input covariance constraints (${\mathcal{H}}_2$ constraints on the control inputs) in the presence of sensor aging. The closed-loop system stability and performance, in terms of mixed ${\mathcal{H}}_2$/${\mathcal{H}}_{\mathrm{\infty }}$ performances, relative improvement, numerical complexity, computation time, and initial conditions response, are studied, and a numerical example is used to illustrate the effectiveness of the proposed control scheme. The synthesised controller guarantees not only the stability but also the closed-loop mixed ${\mathcal{H}}_2$/${\mathcal{H}}_{\mathrm{\infty }}$ performances, and it is feasible for real-time applications.

Keywords:

• Linear parameter varying (LPV) system
• input covariance constraints (ICC) control
• gain-scheduled control
• sensor aging; fault tolerant control (FTC)
• mixed ${\mathcal{H}}_2$/${\mathcal{H}}_{\mathrm{\infty }}$ control

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Aqeel Madhag  http://orcid.org/0000-0002-7731-0272