Fernando Castaños

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The robustness properties of integral sliding-mode controllers are studied. This note shows how to select the projection matrix in such a way that the euclidean norm of the resulting perturbation is minimal. It is also shown that when the minimum is attained, the resulting perturbation is not amplified. This selection is particularly useful if integral(More)
We consider the problem of designing an integral sliding mode controller to reduce the disturbance terms that act on nonlinear systems with state-dependent drift and input matrix. The general case of both, matched and unmatched disturbances affecting the system is addressed. It is proved that the definition of a suitable sliding manifold and the generation(More)
The dynamics of many physical processes can be suitably described by Port-Hamiltonian (PH) models, where the importance of the energy function, the interconnection pattern and the dissipation of the system is underscored. To regulate the behavior of PH systems it is natural to adopt a Passivity-Based Control (PBC) perspective, where the control objectives(More)
The robustness properties of integral sliding mode and H∞ control are exploited in the context of decentralized control. It is shown that integral sliding mode design successfully rejects the matched interconnections right from the initial time. It is demonstrated that by a proper selection of the sliding surface parameters, the effect of the unmatched(More)
It is well known that if the linear time invariant system ẋ = Ax + Bu, y = Cx is passive the associated incremental system ̇̃ x = Ax̃ + Bũ, ỹ = Cx̃, with (̃·) = (·) − (·), u,y the constant input and output associated to an equilibrium state x, is also passive. In this paper, we identify a class of nonlinear passive systems of the form ẋ = f(x) + gu, y =(More)
Passivity-based controllers (PBCs) achieve stabilization of nonlinear systems, rendering the closed-loop passive with a desired energy (storage) function. A natural question is under which conditions is it possible to make this function equal to the difference between the plant and controller energies— when the controller is said to be energy-balancing. In(More)
Implicit and explicit representations of smooth, finite-dimensional port-Hamiltonian systems are studied from the perspective of their use in numerical simulation and control design. Implicit representations arise when a system is modeled in Cartesian coordinates and when the system constraints are applied in the form of additional algebraic equations.(More)
A sliding surface where unmatched unknown inputs are attenuated via a reduced order H∞ control is designed. By a discontinuous control action, the surface is reached exactly in finite time, guaranteeing the minimization of the unmatched disturbance. Complete state measurements are not necessary. Being the output feedback sliding mode control for the case of(More)