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In hydrogeology, estimating aquifer permeability is an important issue. This can be useful in understanding the flow of pollutants from one area of an aquifer to another. For this aquifer analysis sake, the Hydrogeological Experimental Site of Poitiers (France) covering a limestone aquifer is an appropriate instrumented test bed enabling measurement of hydraulic responses of a series of observation wells due to a step-type pumping out excitation at a given well. Given the input-output data, black-box continous-time modeling is quite a straight forward process as shown in this paper. The aim is then to be able to use the identified parameters to classify the different wells according to how sensitive they are to the one having been excited. A correlation between black-box parameters and hydrogeological ones is then established.

This paper presents a vision based cart-inverted pendulum (CIP) system under a hybrid feedback configuration: the continuous cart's position measured by encoder and the delayed & sampled inverted pendulum's upper coordinates, obtained from a visual sensor. The challenge here is to stabilize the CIP from a big inclined initial angle by using a low cost CCD camera. Under this scheme, we propose a hybrid control which consists in a jumping-up (bang-bang) control and a two causal stabilization loops control: the first one (inner loop) realizes a linearization and the stabilization control of the pendulum based on an innovative piecewise continuous reduced order Luenberger observer (PCROLO) coupled with a linearization module, the second one (the outer loop) realizes a Lyapunov based control for the unstable internal system with lower dynamics than that of the pendulum. This hybrid control method is capable of balancing the CIP system within small cart's displacement. Performances issues of the proposed method are illustrated by the experimental figures and videos.

This paper presents a stabilization control system of a 2-DOF inverted pendulum. The challenge is to realize a control with a contact-less feedback including a low cost CCD camera. The global control system uses two feedback loops. The first one (inner loop) includes the delayed and sampled inverted pendulum's top coordinates, obtained from the CCD camera and the second one (outer loop) concerns the cart's position in continuous time (obtained from encoders). With this feedback scheme, we propose a specific control method by choosing an optimal balancing plane at each camera's sampling instant, in view of transforming the 2-DOF pendulum problem to a 1-DOF one. Then in this balancing plane, we realize two control loops: The inner loop, relative to the pendulum's angle, is controlled by a linearization and stabilization method based on an innovative observer called piecewise continuous reduced-order Luenberger observer (PCROLO). The outer loop uses a Lyapunov function based control scheme with slower internal dynamics compared to that of the pendulum, considering that the global controlled system (cart + pendulum) is an unstable non-minimum-phase system. Numerical simulations show that the stabilization control of the inverted pendulum on an x-y robot that are strongly non linear is successful.

This article presents a control method to realize tracking of linear plants that deliver a delayed and sampled output. To do so, we make use of a class of piecewise functioning controller (PFC): bi-sampled controller. The use of this type of controller allows sampled tracking with a delay twice as much as that on the plant's output. Thus, we propose mathematical approach of the dynamics of our controller. We then give an adaptation of these mathematical approaches, using only the delayed and sampled output, by means of a reduced-order Luenberger observer. Computer simulation results are given so as to enhance the theoretical aspect of our method.