978 research outputs found
Incremental Dissipativity based Control of Discrete-Time Nonlinear Systems via the LPV Framework
Unlike for Linear Time-Invariant (LTI) systems, for nonlinear systems, there
exists no general framework for systematic convex controller design which
incorporates performance shaping. The Linear Parameter-Varying (LPV) framework
sought to bridge this gap by extending convex LTI synthesis results such that
they could be applied to nonlinear systems. However, recent literature has
shown that naive application of the LPV framework can fail to guarantee the
desired asymptotic stability guarantees for nonlinear systems. Incremental
dissipativity theory has been successfully used in the literature to overcome
these issues for Continuous-Time (CT) systems. However, so far no solution has
been proposed for output-feedback based incremental control for the
Discrete-Time (DT) case. Using recent results on convex analysis of incremental
dissipativity for DT nonlinear systems, in this paper, we propose a convex
output-feedback controller synthesis method to ensure closed-loop incremental
dissipativity of DT nonlinear systems via the LPV framework. The proposed
method is applied on a simulation example, demonstrating improved stability and
performance properties compared to a standard LPV controller design.Comment: Accepted to 60th Conference on Decision and Control, Austin, 202
Robust and Resilient State Dependent Control of Discrete-Time Nonlinear Systems with General Performance Criteria
A novel state dependent control approach for discrete-time nonlinear systems with general performance criteria is presented. This controller is robust for unstructured model uncertainties, resilient against bounded feedback control gain perturbations in achieving optimality for general performance criteria to secure quadratic optimality with inherent asymptotic stability property together with quadratic dissipative type of disturbance reduction. For the system model, unstructured uncertainty description is assumed, which incorporates commonly used types of uncertainties, such as norm-bounded and positive real uncertainties as special cases. By solving a state dependent linear matrix inequality at each time step, sufficient condition for the control solution can be found which satisfies the general performance criteria. The results of this paper unify existing results on nonlinear quadratic regulator, H∞ and positive real control to provide a novel robust control design. The effectiveness of the proposed technique is demonstrated by simulation of the control of inverted pendulum
Minimality properties of set-valued processes and their pullback attractors
We discuss the existence of pullback attractors for multivalued dynamical
systems on metric spaces. Such attractors are shown to exist without any
assumptions in terms of continuity of the solution maps, based only on
minimality properties with respect to the notion of pullback attraction. When
invariance is required, a very weak closed graph condition on the solving
operators is assumed. The presentation is complemented with examples and
counterexamples to test the sharpness of the hypotheses involved, including a
reaction-diffusion equation, a discontinuous ordinary differential equation and
an irregular form of the heat equation.Comment: 33 pages. A few typos correcte
Passivity Degradation In Discrete Control Implementations: An Approximate Bisimulation Approach
In this paper, we present some preliminary results for compositional analysis
of heterogeneous systems containing both discrete state models and continuous
systems using consistent notions of dissipativity and passivity. We study the
following problem: given a physical plant model and a continuous feedback
controller designed using traditional control techniques, how is the
closed-loop passivity affected when the continuous controller is replaced by a
discrete (i.e., symbolic) implementation within this framework? Specifically,
we give quantitative results on performance degradation when the discrete
control implementation is approximately bisimilar to the continuous controller,
and based on them, we provide conditions that guarantee the boundedness
property of the closed-loop system.Comment: This is an extended version of our IEEE CDC 2015 paper to appear in
Japa
Robust and Resilient State-dependent Control of Continuous-time Nonlinear Systems with General Performance Criteria
A novel state-dependent control approach for continuous-time nonlinear systems with general performance criteria is presented in this paper. This controller is optimally robust for model uncertainties and resilient against control feedback gain perturbations in achieving general performance criteria to secure quadratic optimality with inherent asymptotic stability property together with quadratic dissipative type of disturbance reduction. For the system model, unstructured uncertainty description is assumed, which incorporates commonly used types of uncertainties, such as norm-bounded and positive real uncertainties as special cases. By solving a state-dependent linear matrix inequality at each time, sufficient condition for the control solution can be found which satisfies the general performance criteria. The results of this paper unify existing results on nonlinear quadratic regulator, H∞ and positive real control. The efficacy of the proposed technique is demonstrated by numerical simulations of the nonlinear control of the inverted pendulum on a cart system
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