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Abstract: In this article we propose a reduced model of the input–output behaviour of an arterial compartment, including the short systolic phase where wave phenomena are predominant. The objective is to provide basis for model-based signal processing methods for the estimation from non-invasive measurements and the interpretation of the characteristics of these waves. Due to phenomena such that peaking and steepening, the considered pressure pulse waves behave more like solitons generated by a Korteweg–de Vries (KdV) model than like linear waves. So we start with a quasi-1D Navier–Stokes equation taking into account radial acceleration of the wall: the radial acceleration term being supposed small, a 2scale singular perturbation technique is used to separate the fast wave propagation phenomena taking place in a boundary layer in time and space described by a KdV equation from the slow phenomena represented by a parabolic equation leading to two-elements windkessel models. Some particular solutions of the KdV equation, the 2 and 3-soliton solutions, seems to be good candidates to match the observed pressure pulse waves. Some very promising preliminary comparisons of numerical results obtained along this line with real pressure data are shown. [Copyright &y& Elsevier]

This paper proposes a reduced fuel cell stack model for control and fault diagnosis which was validated with experimental data. Firstly, the electro-chemical phenomena are modeled based on a mechanism of gas adsorption/desorption on catalysts at the anode and at the cathode of the stack, including activation, diffusion, and carbon monoxide poisoning. The electrical voltage of a stack cell is then modeled by the difference between the two electrode potentials. A simplified thermal model of the fuel cell stack is also developed in order to take into account heat generation from reactions, heat transfers, and evaporation/condensation of water. Finally, the efficiency ratio is computed as a model output. It is used to evaluate the efficiency changes of the entire system, providing an important indicator for fault detection.

Leaf spring suspension systems, commonly used in industrial vehicles, have strong nonlinear behaviors. We proposein this paper to model the total force generated by a leaf spring as the result ofa spring elastic force and a dry friction force. The considered dry friction model is based on a particular formof the differential hysteresis models proposed by one of the authors of this paper in earlier works. We alsoestablish the relationship between our model and a discrete-time model existing in the literature through a discretization and a change of parametrization. Results obtained from experimentations on a real truck illustrate theeffectiveness of the proposed model and the associated identification method.

A new dynamic model of the generation of shear forces by pneumatic tires for all speed is proposed. This model is suitable for a wide range of applications from the study of steering performance of vehicle at low speed to realism enhancement for interactive vehicle simulator. The elastic deformation of the belt with respect to the rim is takeninto account, along with the elasto-plastic behavior of rubber-road contact in the contact patch. The model reproduce tire behaviors like frictional vertical torque at standstill, lateral force and vertical torque due to yaw speed, and also relaxation length behavior. Moreover, as the “Pacejka Magic Formula”, it represents very well the standard stationary friction curves.

We analyze the behaviour of the solution of a linear differential equation of retarded type when the delays vary, for Lpinitial conditions, given some p∈[1,∞]. First, we state continuity and differentiability results for the solution viewed as function of the delays. Those regularity results are applied to analyze the small delay sensitivity for quadratic performance index associated to stabilization with a finite dimensional a priori feedback.

Abstract: The biological meaning of follicular development is to free fertilizable oocytes at the time of ovulation. The ovulation rate results from an FSH-dependent follicle selection process. In this paper, we designed a multi-scale model of follicular development, where selection arises from the endocrine feedback between the ovaries and pituitary gland and appeals to control theory concepts. Each ovarian follicle is described through a 2D density function giving an age and maturity-structured description of its cell population. The control intervenes in the velocity, gain and loss terms of the conservation law ruling the changes in the density. The model accounts for the changes in the total cell number, growth fraction and global maturity of both ovulatory and degenerating follicles for various intensities of the selection rate. The different selection process outputs (mono- or poly-ovulation, anovulation) predicted by the model are consistent with physiological knowledge regarding vascularization, pituitary sensitivity to ovarian feedback and treatment with exogenous FSH. [Copyright &y& Elsevier]