Browse/search for people

Publication - Professor Mark Lowenberg

    Nonlinear stability and post-critical analysis of an uncertain plant with Describing Functions and Integral Quadratic Constraints

    Citation

    Iannelli, A, Marcos, A & Lowenberg, M, 2018, ‘Nonlinear stability and post-critical analysis of an uncertain plant with Describing Functions and Integral Quadratic Constraints’. in: 2017 IEEE 56th Annual Conference on Decision and Control, CDC 2017. Institute of Electrical and Electronics Engineers (IEEE), pp. 1828-1833

    Abstract

    Two approaches to tackle the nonlinear robust stability problem of a plant are considered. The first employs a combination of the Describing Function method and μ analysis, while the second makes use of Integral Quadratic Constraints (IQCs). The model analyzed consists of an open-loop wing's airfoil subject to freeplay and LTI parametric uncertainties.One of the main contributions of the work is to provide methodologies to quantitatively determine the post-critical behaviour of the system, known as Limit Cycle Oscillation (LCO). When the first approach is adopted, this is studied by means of a worst-case LCO curve, whose definition is given in the paper. The IQC framework, typically used to find asymptotic stability certificates, is applied to this scenario by introducing a restricted sector bound condition for the nonlinearity.

    Full details in the University publications repository