Emmanuel Witrant

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This paper proposes a control-oriented approach to the tokamak plasma current profile dynamics. It is established based on a consistent set of simplified relationships, in particular for the microwave current drive sources, rather than exact physical modelling. Assuming that a proper model for advanced control schemes can be established using the socalled(More)
In this paper we investigate the problem of remote stabilization via communication networks. This problem arises when the control law is remotely implemented. The exchange of data between the controller and the system is done via a data communication network described by a deterministic model. This leads to the problem of stabilizing an open-loop unstable(More)
A new model-based controller for the magnetic flux profile in a Tokamak plasma was developed using a simplified model of the magnetic flux dynamics. This simplified model is based on physically relevant dynamics that take into account the distributed nature of the system. Shape constraints on the controlled inputs are introduced, representing the(More)
In this paper, we investigate the stability problems and control issues that occur in a reversed-field pinch (RFP) device, EXTRAP-T2R (T2R), used for research in fusion plasma physics and general plasma (ionized gas) dynamics. The plant exhibits, among other things, magnetohydrodynamic instabilities known as resistive-wall modes (RWMs), growing on a(More)
Methane is an important greenhouse gas that is emitted from multiple natural and anthropogenic sources. Atmospheric methane concentrations have varied on a number of timescales in the past, but what has caused these variations is not always well understood. The different sources and sinks of methane have specific isotopic signatures, and the isotopic(More)
Remote control over wireless multi-hop networks is considered. Time-varying delays for the transmission of sensor and control data over the wireless network are caused by a randomized multi-hop routing protocol. The characterstics of the routing protocol together with lower-layer network mechanisms give rise to a delay process with high variance and(More)
This paper describes a new industrial case on automation, for large-scale systems with high environmental impact: the mining ventilation control systems. Ventilation control is essential for the operation of a mine in terms of safety (CO and NOx regulation) and energy optimization. We first discuss a novel regulation architecture, highlighting the interest(More)
In this paper, a strict Lyapunov function is developed in order to show the exponential stability and input-to-state stability (ISS) properties of a diffusion equation for nonhomogeneous media. Such media can involve rapidly time-varying distributed diffusivity coefficients. Based on this Lyapunov function, a control law is derived to preserve the ISS(More)
Input-to-state stability (ISS) of a diffusive equation with Dirichlet boundary conditions is shown, in the Lnorm, with respect to boundary disturbances. In particular, the spatially distributed diffusion coefficients are allowed to be rapidly, yet smoothly, time-varying within a given set. Based on a Lyapunov function for the system with homogeneous(More)
Systems of conservation laws and systems of balance laws are considered in this paper. These kinds of infinite dimensional systems are described by a linear hyperbolic partial differential equation with and without a linear source term. The dynamics and the boundary conditions are subject to a switching signal that is a piecewise constant function. By means(More)