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Enikov E.T.,University of Arizona | Escareno J.-A.,Polytechnic Institute of Advanced Science | Rakotondrabe M.,FEMTO ST Institute
ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) | Year: 2015

To date, most autonomous micro air vehicles (MAV-s) operate in a controlled environment, where the location of and attitude of the aircraft are measured with an infrared (IR) tracking systems. If MAV-s are to ever exit the lab, their flight control needs to become autonomous and based on on-board image and attitude sensors. To address this need, several groups are developing monocular and binocular image based navigation systems. One of the challenges of these systems is the need for exact calibration in order to determine the vehicle's position and attitude through the solution of an inverse problem. Body schemas are a biologically-inspired approach, emulating the plasticity of the animal brain, which allows it to learn non-linear mappings between the body configurations, i.e. its generalized coordinates and the resulting sensory outputs. The advantages of body schemas has long been recognized in the cognitive robotic literature and resulting studies on human-robot interactions based on artificial neural networks, however little effort has been made so far to develop avian-inspired flight control strategies utilizing body and image schemas. This paper presents a numerical experiment of controlling the trajectory of a miniature rotorcraft during landing maneuvers suing the notion of body and image schemas. More specifically, we demonstrate how trajectory planning can be executed in the image space using gradient-based maximum seeking algorithm of a pseudo-potential. It is demonstrated that a neural-gas type artificial neural network (ANN), trained through Hebbian-type learning algorithm, can be effective in learning a mapping between the rotorcraft's position/attitude and the output of its vision sensors. Numerical simulation of the landing performance, including resulting landing errors are presented using an experimentally validated rotorcraft model. Copyright © 2015 by ASME.


Boussaada I.,University Paris - Sud | Boussaada I.,Polytechnic Institute of Advanced Science
Journal of Computational and Nonlinear Dynamics | Year: 2012

The problem of local linearizability of the planar linear center perturbed by cubic non- linearities in all generalities on the system parameters (14 parameters) is far from being solved. The synchronization problem (as noted in Pikovsky, A., Rosenblum, M., and Kurths, J., 2003, Synchronization: A Universal Concept in Nonlinear Sciences, Cambridge Nonlinear Science Series, Cambridge University Press, UK, and Blekhman, I. I., 1988, Synchronisation in Science and Technology, ASME Press Translations, New York) consists in bringing appropriate modifications on a given system to obtain a desired dynamic. The desired phase portrait along this paper contains a compact region around a singular point at the origin in which lie periodic orbits with the same period (independently from the chosen initial conditions). In this paper, starting from a five parameters non isochronous Chouikha cubic system (Chouikha, A. R., 2007, Isochronous Centers of Lienard Type Equations and Applications, J. Math. Anal. Appl., 331, pp. 358-376) we identify all possible monomial perturbations of degree d {2, 3} insuring local linearizability of the perturbed system. The necessary conditions are obtained by the Normal Forms method. These conditions are real algebraic equations (multivariate polynomials) in the parameters of the studied ordinary differential system. The efficient algorithm FGb (J. C. Faugre, FGb Salsa Software, http://fgbrs.lip6.fr) for computing the Gröbner basis is used. For the family studied in this paper, an exhaustive list of possible parameters values insuring local linearizability is established. All the found cases are already known in the literature but the contexts are different since our object is the synchronisation rather than the classification. This paper can be seen as a direct continuation of several new works concerned with the hinting of cubic isochronous centers, (in particular Bardet, M., and Boussaada, I., 2011, Compexity Reduction of C-algorithm, App. Math. Comp., in press; Boussaada, I., Chouikha, A. R., and Strelcyn, J.-M., 2011, Isochronicity Conditions for some Planar Polynomial Systems, Bull. Sci. Math, 135(1), pp. 89-112; Bardet, M., Boussaada, I., Chouikha, A. R., and Strelcyn, J.-M., 2011, Isochronicity Conditions for some Planar Polynomial Systems, Bull. Sci. Math, 135(2), pp. 230-249; and furthermore, it can be considered as an adaptation of a qualitative theory method to a synchronization problem. © 2012 American Society of Mechanical Engineers.


Boussaada I.,University Paris - Sud | Boussaada I.,Polytechnic Institute of Advanced Science | Niculescu S.-I.,University Paris - Sud
IFAC Proceedings Volumes (IFAC-PapersOnline) | Year: 2014

The use of Pyragas-Type controller proved interest in the stabilization of unstable periodic orbits. The stabilization problem of a balancing inverted pendulum on an horizontally moving cart by the use of such a controller is considered. The main objective of the paper is to propose delayed control law containing only proportional gains able to stabilize the inverted pendulum by avoiding the existence of a triple zero eigenvalue at the origin. We analyze the center dynamics described by a three dimensional system of ordinary differential equations (ODEs) with a codimension-three triple zero bifurcation. Furthermore, the stability analysis of the corresponding linear time invariant system with two delays describing the behavior around the equilibrium is also proposed. This analysis is done in order to characterize the possible local bifurcations. Finally, the proposed control scheme is numerically illustrated and discussed. Time-Delay, Stability, Delayed Feedback, Control, Center Manifold Theorem, Normal Forms, Local Bifurcation, Inverted Pendulum. © IFAC.


Beauvalet L.,University Pierre and Marie Curie | Robert V.,University Pierre and Marie Curie | Robert V.,Polytechnic Institute of Advanced Science | Lainey V.,University Pierre and Marie Curie | And 2 more authors.
Astronomy and Astrophysics | Year: 2013

Because of Pluto's distance from the Sun, the Pluto system has not yet completed a revolution since its discovery, hence an uncertain heliocentric distance. In this paper, we present the fitting of our dynamical model ODIN (Orbite, Dynamique et Intégration Numérique) to observations. The small satellites P4 and P5 are not taken into account. We fitted our model to the measured absolute coordinates (RA, DEC) of Pluto, and to the measured positions of the satellites relative to Pluto. The masses we found for the bodies of the system are consistent with those of previous studies. Yet the masses of the small satellites Nix and Hydra are artificially constrained by the number of observations of Charon. The best way to improve the determination of their masses would be to use observations of P4 and P5, but there are still not enough published observations. Concerning the heliocentric distance of the system, we compared the value we obtained using ODIN and those of other models. The difference between the models far exceeds the uncertainty needed (about 1000 km) for the mission New Horizons. A new astrometric reduction of old photographic plates may be an efficient way to constrain this distance. The ephemeris for Pluto's satellites is available on the web page of the IMCCE at http://www.imcce.fr/hosted-sites/saimirror/nssreq9hf.htm. The complete version of the ephemeris is available as a SPICE kernel at http://www.imcce.fr/ beauvalet/. © 2013 ESO.


PubMed | University of Aveiro and Polytechnic Institute of Advanced Science
Type: Journal Article | Journal: Sports biomechanics | Year: 2016

This study aimed to compare knee joint position sense of roller hockey players with an age-matched group of non-athletes. Forty-three male participants voluntarily participated in this cross-sectional study: 21 roller hockey players (mean age: 23.24.2years old, mean weight: 81.89.8kg, mean height: 180.54.1cm) and 22 age-matched non-athletes (mean age: 23.73.9years old, mean weight: 85.06.2kg, mean height: 181.55.0cm). Knee joint position sense of the dominant limb was evaluated using a technique of open-kinetic chain and active knee positioning. Joint position sense was reported using absolute, relative and variable angular errors. The main results indicated that the group of roller hockey players showed significantly lower absolute (2.41.2 vs. 6.53.2, p0.001) and relative (1.72.1 vs. 5.84.4, p0.001) angular errors in comparison with the non-athletes group. In conclusion, the results from this present study suggest that proprioceptive acuity, assessed by measuring joint position sense, is increased in roller hockey players. The enhanced proprioception of the roller hockey players could contribute to injury prevention and improved performance during sporting activities.


Coimbra S.,Polytechnic Institute of Advanced Science | Coimbra S.,University of Porto | Figueiredo A.,University of Coimbra | Santos-Silva A.,University of Porto
Core Evidence | Year: 2014

Advances in knowledge regarding the pathogenesis of psoriasis have allowed the development of a new class of agents known as biologic drugs. Data confirm that T helper (Th)17 and interleukin (IL)-17 signaling has a crucial role in the pathogenesis of the disease. High levels of IL-17 and Th17-related cytokines have been reported in psoriasis, leading to the suggestion of agents targeting IL-17 as a potential therapeutic strategy in psoriasis. Brodalumab is a human monoclonal antibody that targets IL-17 receptor A, blocking the effects of IL-17A, IL-17F, and IL-17E. Data from Phase I and Phase II clinical trials indicate that brodalumab has a favorable safety and tolerability profile, with strong clinical activity, suggesting that it is a potential tool for use in the treatment of moderate-to-severe psoriasis. © 2014 Coimbra et al.


Belbachir A.,Polytechnic Institute of Advanced Science | Benabid S.,Polytechnic Institute of Advanced Science
International Conference on Applied Electronics | Year: 2016

Several embedded systems use Wireless Sensor Network (WSN) to monitor an area. However, efficient robust and reliable communication between sensors is hard to achieve. Thus, in this paper we focus on exploration area and we propose a new cooperative strategy. This strategy is based on Cognitive Radio (CR) and Software Defined Radio (SDR) that we consider as a 'Smart Communication'. These radio systems search for a vacant spectrum band and reconfigures itself satisfying the requirements of any desired communication standard. Several simulation experiments demonstrate that the proposed approach improve exploration strategy. © 2016 University of West Bohemia.


Benabid S.,Polytechnic Institute of Advanced Science | Aghdam E.N.,Sahand University of Technology
International Conference on Applied Electronics | Year: 2015

A 6th order bandpass continuous-time sigma delta modulator centered at 300MHz suitable for Software Defined Radio receiver is presented. This modulator is implemented in a standard low-cost 0.35μm CMOS technology. Several Q-enhanced LC resonators are implemented in a parallel structure using highly linear operational transconductance amplifiers (OTA), LC tank, and transconductor acts as a negative resistance to compensate the ohmic losses in inductor. Furthermore, an improved method employing two 3-bit flash ADC as a loop quantizer allows to double the sampling frequency and to relax the comparator requirements. Consequently we can design a modulator clocked at 1.2GHz allowing the integration of passive LC-filters in this standard technology. Transistor level simulations show that the modulator achieves a signal-to-noise and distortion-ratio (SNDR) of 82.6dB over a 6MHz signal band. © 2014 University of West Bohemia.


Escareno J.-A.,Polytechnic Institute of Advanced Science | Rakotondrabe M.,University of Franche Comte | Habineza D.,University of Franche Comte
Control Engineering Practice | Year: 2015

This paper deals with the control of a two degrees of freedom (2-DOF) piezoelectric actuator for precise positioning and which exhibits strong hysteresis nonlinearity and strong cross-couplings. To tackle the nonlinearity and the cross-couplings, we propose two decoupled models in which they are considered as (fictive) external disturbances which require proper characterization. Then, a backstepping technique is proposed to construct a robust controller that merges sliding-mode and adaptive schemes. Extensive experimental tests are finally carried out to prove the efficiency of the modeling and control technique proposed. © 2015 Elsevier Ltd.


Enikov E.T.,University of Arizona | Escareno J.-A.,Polytechnic Institute of Advanced Science
ICINCO 2015 - 12th International Conference on Informatics in Control, Automation and Robotics, Proceedings | Year: 2015

To date, most autonomous micro air vehicles (MAV-s) operate in a controlled environment, where the location of and attitude of the aircraft are measured be dedicated high-power computers with IR tracking capability. If MAV-s are to ever exit the lab and carry out autonomous missions, their flight control systems needs to utilize on-board sensors and high-efficiency attitude determination algorithms. To address this need, we investigate the feasibility of using body schemas to carry out path planning in the vision space of the MAV. Body schemas are a biologically-inspired approach, emulating the plasticity of the animal brains, allowing efficient representation of non-linear mapping between the body configuration space, i.e. its generalized coordinates and the resulting sensory outputs. This paper presents a numerical experiment of generating landing trajectories of a miniature rotor-craft using the notion of body and image schemas. More specifically, we demonstrate how a trajectory planning can be executed in the image space using a pseudo-potential functions and a gradientbased maximum seeking algorithm. It is demonstrated that a neural-gas type neural network, trained through Hebbian-type learning algorithm can learn a mapping between the rotor-craft position/attitude and the output of its vision sensors. Numerical simulations of the landing performance of a physical model is also presented, The resulting trajectory tracking errors are less than 8 %.

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