Results 151 to 160 of about 278 (209)

New views of some invariants associated with the Cartesian 2D velocity gradient tensor

open access: yesQuarterly Journal of the Royal Meteorological Society, EarlyView.
Vorticity and divergence of horizontal flow are fundamental quantities in meteorology; both are linear functions of the four elements of the 2D velocity gradient tensor and both are formally unchanged under coordinate rotation. We explore four quadratic functions of the elements that are geometrically invariant in this sense, finding some novel ...
I. Roulstone, S. A. Clough, A. A. White
wiley   +1 more source

Optimal Homogeneous ℒp$$ {\boldsymbol{\mathcal{L}}}_{\boldsymbol{p}} $$‐Gain Controller

open access: yesInternational Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT Nonlinear ℋ∞$$ {\mathscr{H}}_{\infty } $$‐controllers are designed for arbitrarily weighted, continuous homogeneous systems with a focus on systems affine in the control input. Based on the homogeneous ℒp$$ {\mathcal{L}}_p $$‐norm, the input–output behavior is quantified in terms of the homogeneous ℒp$$ {\mathcal{L}}_p $$‐gain as a ...
Daipeng Zhang   +3 more
wiley   +1 more source

Sliding Mode Control in Aerospace Applications: A Survey

open access: yesInternational Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT Sliding mode control (SMC) enjoys robustness to matched and unmatched (in the case of minimum phase input‐output dynamics) bounded perturbations, and finite time convergence. Second‐order and higher‐order sliding mode control systems (2‐SMC/HOSMC) retain all the advantages of sliding mode control, but in addition can be applied to systems of ...
Yuri Shtessel, Christopher Edwards
wiley   +1 more source

Discrete Implementations Modify the Intuition of Final Set Adjustment in Barrier Function Based Control

open access: yesInternational Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT This paper establishes an implementation‐aware framework for Barrier Function Adaptation (BFA) and shows that discrete‐time realizations fundamentally alter the logic of final‐set adjustment. In particular, sufficient conditions are derived to preserve the key benefits of BFA (predefined performance, gain adaptation with uncertain perturbation
Luis Ovalle   +3 more
wiley   +1 more source

Output‐Feedback H∞$$ {H}_{\infty } $$ Detector‐Based Control of Continuous‐Time Markov Jump Lur'e Systems With Sector‐Bound Optimization

open access: yesInternational Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT This paper addresses the problem of dynamic output‐feedback H∞$$ {H}_{\infty } $$ detector‐based control for continuous‐time Markov Jump Lur'e Systems with uncertain transition rate matrices. In contrast to conventional approaches, the proposed synthesis conditions are derived using Finsler's lemma, introducing additional slack variables to ...
Lucas P. M. Silva   +2 more
wiley   +1 more source

Control Systems Design With Enlarged Stability Domains for Nonlinear Constrained Systems via Sum‐of‐Squares Optimization

open access: yesInternational Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT Designing safe control laws for nonlinear systems is challenging, especially when ensuring stability under actuator saturation and state constraints. A key aspect is embedding controllers with a Region of Attraction (ROA), which defines initial conditions guaranteeing convergence to a stable equilibrium point (EP).
Bhaskar Biswas   +3 more
wiley   +1 more source

The Influenzal Constitution. [PDF]

open access: yesProc R Soc Med, 1927
Hamer W.
europepmc   +1 more source

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