https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Tue, 09 Jun 2026 18:59:23 GMT 2026-06-09T18:59:23Z http://hdl.handle.net/10985/8155 Feedrate planning for machining with industrial six-axis robots DAMAK, Mohamed; OLABI, Adel; BEAREE, Richard; GIBARU, Olivier Nowadays, the adaptation of industrial robots to carry out high-speed machining operations is strongly required by the manufacturing industry. This new technology machining process demands the improvement of the overall performances of robots to achieve an accuracy level close to that realized by machine-tools. This paper presents a method of trajectory planning adapted for continuous machining by robot. The methodology used is based on a parametric interpolation of the geometry in the operational space. FIR filters properties are exploited to generate the tool feedrate with limited jerk. This planning method is validated experimentally on an industrial robot. The authors want to thank Stäubli for providing the necessary information of the controller, Dynalog for its contribution to the experimental validations and X. Helle for its material contributions. Fri, 01 Jan 2010 00:00:00 GMT http://hdl.handle.net/10985/8155 2010-01-01T00:00:00Z DAMAK, Mohamed OLABI, Adel BEAREE, Richard GIBARU, Olivier Nowadays, the adaptation of industrial robots to carry out high-speed machining operations is strongly required by the manufacturing industry. This new technology machining process demands the improvement of the overall performances of robots to achieve an accuracy level close to that realized by machine-tools. This paper presents a method of trajectory planning adapted for continuous machining by robot. The methodology used is based on a parametric interpolation of the geometry in the operational space. FIR filters properties are exploited to generate the tool feedrate with limited jerk. This planning method is validated experimentally on an industrial robot. http://hdl.handle.net/10985/6483 c AUQUIERT, Philippe; PERRUQUETTI, Wilfrid; GIBARU, Olivier Nous proposons une alternative à l’équation de Riccati lors de la résolution de systèmes linéaires quadratiques en contrôle optimale. Une transformation de l’équation d’état basée sur la forme de Brunoswski de ce système permet de mettre en évidence une représentation sous la forme de sorties dites plates. Le système ainsi transformé nous permet d’exprimer le problème de contrôle optimal sous la forme d’un problème variationnel. Une approximation par une B-Spline des sorties plates est proposée ainsi que la majoration a posteriori de l’erreur commise. L’intérêt de cette majoration d’erreur est qu’elle permet d’optimiser le placement des noeuds de la B-Spline afin de satisfaire une tolérance donnée. Sun, 01 Jan 2006 00:00:00 GMT http://hdl.handle.net/10985/6483 2006-01-01T00:00:00Z AUQUIERT, Philippe PERRUQUETTI, Wilfrid GIBARU, Olivier Nous proposons une alternative à l’équation de Riccati lors de la résolution de systèmes linéaires quadratiques en contrôle optimale. Une transformation de l’équation d’état basée sur la forme de Brunoswski de ce système permet de mettre en évidence une représentation sous la forme de sorties dites plates. Le système ainsi transformé nous permet d’exprimer le problème de contrôle optimal sous la forme d’un problème variationnel. Une approximation par une B-Spline des sorties plates est proposée ainsi que la majoration a posteriori de l’erreur commise. L’intérêt de cette majoration d’erreur est qu’elle permet d’optimiser le placement des noeuds de la B-Spline afin de satisfaire une tolérance donnée. http://hdl.handle.net/10985/8635 Fast B-Spline 2D Curve Fitting for unorganized Noisy Datasets EL HAYEK, Nadim; DAMAK, Mohamed; NOUIRA, Hichem; ANWER, Nabil; NYIRI, Eric; GIBARU, Olivier In the context of coordinate metrology and reverse engineering, freeform curve reconstruction from unorganized data points still offers ways for improvement. Geometric convection is the process of fitting a closed shape, generally represented in the form of a periodic B-Spline model, to data points [WPL06]. This process should be robust to freeform shapes and convergence should be assured even in the presence of noise. The convection's starting point is a periodic B-Spline polygon defined by a finite number of control points that are distributed around the data points. The minimization of the sum of the squared distances separating the B-Spline curve and the points is done and translates into an adaptation of the shape of the curve, meaning that the control points are either inserted, removed or delocalized automatically depending on the accuracy of the fit. Computing distances is a computationally expensive step in which finding the projection of each of the data points requires the determination of location parameters along the curve. Zheng et al [ZBLW12] propose a minimization process in which location parameters and control points are calculated simultaneously. We propose a method in which we do not need to estimate location parameters, but rather compute topological distances that can be assimilated to the Hausdorff distances using a two-step association procedure. Instead of using the continuous representation of the B-Spline curve and having to solve for footpoints, we set the problem in discrete form by applying subdivision of the control polygon. This generates a discretization of the curve and establishes the link between the discrete point-to-curve distances and the position of the control points. The first step of the association process associates BSpline discrete points to data points and a segmentation of the cloud of points is done. The second step uses this segmentation to associate to each data point the nearest discrete BSpline segment. Results are presented for the fitting of turbine blades profiles and a thorough comparison between our approach and the existing methods is given [ZBLW12, WPL06, SKH98]. Wed, 01 Jan 2014 00:00:00 GMT http://hdl.handle.net/10985/8635 2014-01-01T00:00:00Z EL HAYEK, Nadim DAMAK, Mohamed NOUIRA, Hichem ANWER, Nabil NYIRI, Eric GIBARU, Olivier In the context of coordinate metrology and reverse engineering, freeform curve reconstruction from unorganized data points still offers ways for improvement. Geometric convection is the process of fitting a closed shape, generally represented in the form of a periodic B-Spline model, to data points [WPL06]. This process should be robust to freeform shapes and convergence should be assured even in the presence of noise. The convection's starting point is a periodic B-Spline polygon defined by a finite number of control points that are distributed around the data points. The minimization of the sum of the squared distances separating the B-Spline curve and the points is done and translates into an adaptation of the shape of the curve, meaning that the control points are either inserted, removed or delocalized automatically depending on the accuracy of the fit. Computing distances is a computationally expensive step in which finding the projection of each of the data points requires the determination of location parameters along the curve. Zheng et al [ZBLW12] propose a minimization process in which location parameters and control points are calculated simultaneously. We propose a method in which we do not need to estimate location parameters, but rather compute topological distances that can be assimilated to the Hausdorff distances using a two-step association procedure. Instead of using the continuous representation of the B-Spline curve and having to solve for footpoints, we set the problem in discrete form by applying subdivision of the control polygon. This generates a discretization of the curve and establishes the link between the discrete point-to-curve distances and the position of the control points. The first step of the association process associates BSpline discrete points to data points and a segmentation of the cloud of points is done. The second step uses this segmentation to associate to each data point the nearest discrete BSpline segment. Results are presented for the fitting of turbine blades profiles and a thorough comparison between our approach and the existing methods is given [ZBLW12, WPL06, SKH98]. http://hdl.handle.net/10985/10131 On Algebraic Approach for MSD Parametric Estimation OUESLATI, Marouene; THIERY, Stéphane; MORARU, George; BEAREE, Richard; GIBARU, Olivier This article address the identification problem of the natural frequency and the damping ratio of a second order continuous system where the input is a sinusoidal signal. An algebra based approach for identifying parameters of a Mass Spring Damper (MSD) system is proposed and compared to the Kalman-Bucy filter. The proposed estimator uses the algebraic parametric method in the frequency domain yielding exact formula, when placed in the time domain to identify the unknown parameters. We focus on finding the optimal sinusoidal exciting trajectory which allow to minimize the variance of the identification algorithms. We show that the variance of the estimators issued from the algebraic identification method introduced by Fliess and Sira-Ramirez is less sensitive to the input frequency than the ones obtained by the classical recursive Kalman-Bucy filter. Unlike conventional estimation approach, where the knowledge of the statistical properties of the noise is required, algebraic method is deterministic and non-asymptotic. We show that we don't need to know the variance of the noise so as to perform these algebraic estimators. Moreover, as they are non-asymptotic, we give numerical results where we show that they can be used directly for online estimations without any special setting. Sat, 01 Jan 2011 00:00:00 GMT http://hdl.handle.net/10985/10131 2011-01-01T00:00:00Z OUESLATI, Marouene THIERY, Stéphane MORARU, George BEAREE, Richard GIBARU, Olivier This article address the identification problem of the natural frequency and the damping ratio of a second order continuous system where the input is a sinusoidal signal. An algebra based approach for identifying parameters of a Mass Spring Damper (MSD) system is proposed and compared to the Kalman-Bucy filter. The proposed estimator uses the algebraic parametric method in the frequency domain yielding exact formula, when placed in the time domain to identify the unknown parameters. We focus on finding the optimal sinusoidal exciting trajectory which allow to minimize the variance of the identification algorithms. We show that the variance of the estimators issued from the algebraic identification method introduced by Fliess and Sira-Ramirez is less sensitive to the input frequency than the ones obtained by the classical recursive Kalman-Bucy filter. Unlike conventional estimation approach, where the knowledge of the statistical properties of the noise is required, algebraic method is deterministic and non-asymptotic. We show that we don't need to know the variance of the noise so as to perform these algebraic estimators. Moreover, as they are non-asymptotic, we give numerical results where we show that they can be used directly for online estimations without any special setting. http://hdl.handle.net/10985/7897 Leap Motion pour la capture de mouvement 3D par spline L1 HERNOUX, Franck; BEAREE, Richard; GAJNY, Laurent; NYIRI, Eric; BANCALIN, Julien; GIBARU, Olivier Afin d’accroître leur compétitivité les entreprises ont recours de plus en plus à des systèmes robotisés pour realiser différentes tâches complexes. Ces robots sont très attractifs par leur coût mais nécessitent d’introduire des capteurs externes afin de garantir une plus grande précision de mouvement. Un enjeu majeur concerne la co-activité avec l’homme. Fort de l’acquisition très récente du système de vision low-cost, Leap Motion, qui présente des caractéristiques de précision inégalées à ce coût, nous proposons un premier travail d’apprentissage, par un système robotisé, de la gestuelle d’un opérateur. L’objectif est de reproduire des tâches complexes en 3D sans contraintes pour l’opérateur. Cette interaction permet d’engendrer un nuage de points et de directions très précises. Afin de garantir une bonne répétabilité du mouvement sur notre robot UR10, nous réalisons une interpolation de ces données par des splines polynomiales minimisant la norme L1. Ce formalisme développé récemment présente une complexité de calcul linéaire avec les données et permet de conserver la forme des données même lorsque le pas de discrétisation n’est pas uniforme en espace. Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/10985/7897 2013-01-01T00:00:00Z HERNOUX, Franck BEAREE, Richard GAJNY, Laurent NYIRI, Eric BANCALIN, Julien GIBARU, Olivier Afin d’accroître leur compétitivité les entreprises ont recours de plus en plus à des systèmes robotisés pour realiser différentes tâches complexes. Ces robots sont très attractifs par leur coût mais nécessitent d’introduire des capteurs externes afin de garantir une plus grande précision de mouvement. Un enjeu majeur concerne la co-activité avec l’homme. Fort de l’acquisition très récente du système de vision low-cost, Leap Motion, qui présente des caractéristiques de précision inégalées à ce coût, nous proposons un premier travail d’apprentissage, par un système robotisé, de la gestuelle d’un opérateur. L’objectif est de reproduire des tâches complexes en 3D sans contraintes pour l’opérateur. Cette interaction permet d’engendrer un nuage de points et de directions très précises. Afin de garantir une bonne répétabilité du mouvement sur notre robot UR10, nous réalisons une interpolation de ces données par des splines polynomiales minimisant la norme L1. Ce formalisme développé récemment présente une complexité de calcul linéaire avec les données et permet de conserver la forme des données même lorsque le pas de discrétisation n’est pas uniforme en espace. http://hdl.handle.net/10985/7745 Improving the Accuracy of Industrial Robots by offline Compensation of Joints Errors DAMAK, Mohamed; LELEU, Stéphane; OLABI, Adel; BEAREE, Richard; GIBARU, Olivier The use of industrial robots in many fields of industry like prototyping, pre-machining and end milling is limited because of their poor accuracy. Robot joints are mainly responsible for this poor accuracy. The flexibility of robots joints and the kinematic errors in the transmission systems produce a significant error of position in the level of the end-effector. This paper presents these two types of joint errors. Identification methods are presented with experimental validation on a 6 axes industrial robot, STAUBLI RX 170 BH. An offline correction method used to improve the accuracy of this robot is validated experimentally. Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/10985/7745 2013-01-01T00:00:00Z DAMAK, Mohamed LELEU, Stéphane OLABI, Adel BEAREE, Richard GIBARU, Olivier The use of industrial robots in many fields of industry like prototyping, pre-machining and end milling is limited because of their poor accuracy. Robot joints are mainly responsible for this poor accuracy. The flexibility of robots joints and the kinematic errors in the transmission systems produce a significant error of position in the level of the end-effector. This paper presents these two types of joint errors. Identification methods are presented with experimental validation on a 6 axes industrial robot, STAUBLI RX 170 BH. An offline correction method used to improve the accuracy of this robot is validated experimentally. http://hdl.handle.net/10985/7755 LNE Activies in Nanometrology: flatness reference calibration algorithm LAHOUSSE, Ludovic; BORIPATKOSOL, Siriwan; LELEU, Stéphane; DAVID, Jean-Marie; DUCOURTIEUX, Sébastien; COOREVITS, Thierry; GIBARU, Olivier The Laboratoire National de Métrologie et d’Essais (LNE) has developed an innovative ultra precision coordinate measuring machine [LAH07] traceable to the national length standard to measure three-dimensional objects with nanometric uncertainties (figure 1). The measuring range is 300 mm x 300 mm x 50 μm. The objective in term of uncertainty is to reach 30 nm in X and Y directions for a displacement of 300 mm and about few nanometers for a vertical displacement of 50 μm. On this machine, we use four capacitive sensors to measure the position along z direction. These sensors target the flat surface of cylinders (300 mm diameter) used as flatness references. To measure the shape of these aluminum references with nanometric uncertainties, we propose a measurement method based on a propagation process in which we introduce an angular measurement to compensate the curvature error inherent in this method. The measurement process uses the same sensor technology (capacitive sensor) we use on the machine. This paper presents the measurement method, its validation and the first results. Tue, 01 Jan 2008 00:00:00 GMT http://hdl.handle.net/10985/7755 2008-01-01T00:00:00Z LAHOUSSE, Ludovic BORIPATKOSOL, Siriwan LELEU, Stéphane DAVID, Jean-Marie DUCOURTIEUX, Sébastien COOREVITS, Thierry GIBARU, Olivier The Laboratoire National de Métrologie et d’Essais (LNE) has developed an innovative ultra precision coordinate measuring machine [LAH07] traceable to the national length standard to measure three-dimensional objects with nanometric uncertainties (figure 1). The measuring range is 300 mm x 300 mm x 50 μm. The objective in term of uncertainty is to reach 30 nm in X and Y directions for a displacement of 300 mm and about few nanometers for a vertical displacement of 50 μm. On this machine, we use four capacitive sensors to measure the position along z direction. These sensors target the flat surface of cylinders (300 mm diameter) used as flatness references. To measure the shape of these aluminum references with nanometric uncertainties, we propose a measurement method based on a propagation process in which we introduce an angular measurement to compensate the curvature error inherent in this method. The measurement process uses the same sensor technology (capacitive sensor) we use on the machine. This paper presents the measurement method, its validation and the first results. http://hdl.handle.net/10985/8646 Reconstruction of freeform surfaces for metrology EL HAYEK, Nadim; NOUIRA, Hichem; ANWER, Nabil; DAMAK, Mohamed; GIBARU, Olivier The application of freeform surfaces has increased since their complex shapes closely express a product's functional specifications and their machining is obtained with higher accuracy. In particular, optical surfaces exhibit enhanced performance especially when they take aspheric forms or more complex forms with multi-undulations. This study is mainly focused on the reconstruction of complex shapes such as freeform optical surfaces, and on the characterization of their form. The computer graphics community has proposed various algorithms for constructing a mesh based on the cloud of sample points. The mesh is a piecewise linear approximation of the surface and an interpolation of the point set. The mesh can further be processed for fitting parametric surfaces (Polyworks® or Geomagic®). The metrology community investigates direct fitting approaches. If the surface mathematical model is given, fitting is a straight forward task. Nonetheless, if the surface model is unknown, fitting is only possible through the association of polynomial Spline parametric surfaces. In this paper, a comparative study carried out on methods proposed by the computer graphics community will be presented to elucidate the advantages of these approaches. We stress the importance of the pre-processing phase as well as the significance of initial conditions. We further emphasize the importance of the meshing phase by stating that a proper mesh has two major advantages. First, it organizes the initially unstructured point set and it provides an insight of orientation, neighbourhood and curvature, and infers information on both its geometry and topology. Second, it conveys a better segmentation of the space, leading to a correct patching and association of parametric surfaces. Wed, 01 Jan 2014 00:00:00 GMT http://hdl.handle.net/10985/8646 2014-01-01T00:00:00Z EL HAYEK, Nadim NOUIRA, Hichem ANWER, Nabil DAMAK, Mohamed GIBARU, Olivier The application of freeform surfaces has increased since their complex shapes closely express a product's functional specifications and their machining is obtained with higher accuracy. In particular, optical surfaces exhibit enhanced performance especially when they take aspheric forms or more complex forms with multi-undulations. This study is mainly focused on the reconstruction of complex shapes such as freeform optical surfaces, and on the characterization of their form. The computer graphics community has proposed various algorithms for constructing a mesh based on the cloud of sample points. The mesh is a piecewise linear approximation of the surface and an interpolation of the point set. The mesh can further be processed for fitting parametric surfaces (Polyworks® or Geomagic®). The metrology community investigates direct fitting approaches. If the surface mathematical model is given, fitting is a straight forward task. Nonetheless, if the surface model is unknown, fitting is only possible through the association of polynomial Spline parametric surfaces. In this paper, a comparative study carried out on methods proposed by the computer graphics community will be presented to elucidate the advantages of these approaches. We stress the importance of the pre-processing phase as well as the significance of initial conditions. We further emphasize the importance of the meshing phase by stating that a proper mesh has two major advantages. First, it organizes the initially unstructured point set and it provides an insight of orientation, neighbourhood and curvature, and infers information on both its geometry and topology. Second, it conveys a better segmentation of the space, leading to a correct patching and association of parametric surfaces. http://hdl.handle.net/10985/6354 Création d’un « étalon métrologique » d’une roue dentée sur Machine à Mesurer Tridimensionnelle DAVID, Jean-Marie; LELEU, Stéphane; BAUDOUIN, Cyrille; GIBARU, Olivier La problématique de mesure de pièces complexes, présentant des formes symétriques suivant un axe de rotation telles que les roues dentées par exemple, avec de faibles incertitudes de mesures est exposée. La création d’un étalon de très grande qualité métrologique, à partir d’une pièce physique issue de la production, est présentée avec la mise en oeuvre d’une technique d’élimination d’erreurs par multi–retournement sous Machine à Mesurer Tridimensionnelle. L’objet du présent article est de décrire le processus d’élimination d’erreurs et de moyennage qui permet d’obtenir certaines caractéristiques de la pièce avec un niveau d’incertitudes très faibles. Cette analyse est effectuée théoriquement et confirmée par simulation numérique. Les résultats expérimentaux de la qualification d’un pignon conique de différentiel automobile par cette technique confirment son statut d’étalon métrologique avec un très faible niveau d’incertitudes, en particulier pour l’erreur de pas. The issue of the measurement of elaborate parts displaying symmetrical shapes along a rotation axis with low measurement deviations such as gears is addressed. The creation of a very high metrological quality measurement standard made from a manufactured physical part is exposed with the implementation of an error elimination method of tooth by tooth rotation on a Coordinate Measuring Machine. The purpose of this article is to describe the error elimination and averaging process enabling the acquiring of some characteristics of the part with a very low deviation level. This analysis is realised theoretically and confirmed with numerical simulation. Experimental results of the qualification of an automobile differential bevel gear with this technique confirm its very low deviation level measurement standard status, particularly for pitch error. Mon, 01 Jan 2007 00:00:00 GMT http://hdl.handle.net/10985/6354 2007-01-01T00:00:00Z DAVID, Jean-Marie LELEU, Stéphane BAUDOUIN, Cyrille GIBARU, Olivier La problématique de mesure de pièces complexes, présentant des formes symétriques suivant un axe de rotation telles que les roues dentées par exemple, avec de faibles incertitudes de mesures est exposée. La création d’un étalon de très grande qualité métrologique, à partir d’une pièce physique issue de la production, est présentée avec la mise en oeuvre d’une technique d’élimination d’erreurs par multi–retournement sous Machine à Mesurer Tridimensionnelle. L’objet du présent article est de décrire le processus d’élimination d’erreurs et de moyennage qui permet d’obtenir certaines caractéristiques de la pièce avec un niveau d’incertitudes très faibles. Cette analyse est effectuée théoriquement et confirmée par simulation numérique. Les résultats expérimentaux de la qualification d’un pignon conique de différentiel automobile par cette technique confirment son statut d’étalon métrologique avec un très faible niveau d’incertitudes, en particulier pour l’erreur de pas. The issue of the measurement of elaborate parts displaying symmetrical shapes along a rotation axis with low measurement deviations such as gears is addressed. The creation of a very high metrological quality measurement standard made from a manufactured physical part is exposed with the implementation of an error elimination method of tooth by tooth rotation on a Coordinate Measuring Machine. The purpose of this article is to describe the error elimination and averaging process enabling the acquiring of some characteristics of the part with a very low deviation level. This analysis is realised theoretically and confirmed with numerical simulation. Experimental results of the qualification of an automobile differential bevel gear with this technique confirm its very low deviation level measurement standard status, particularly for pitch error. http://hdl.handle.net/10985/7472 Towards CNC Automation in AFM Probe-Based Nano Machining BROUSSEAU, Emmanuel; ARNAL, Benoît; THIERY, Stéphane; MAYOR, J.Rhett; NYIRI, Eric; GIBARU, Olivier This paper presents a feasibility study, which aims to demonstrate the applicability of the CNC automation philosophy for the process of AFM probe-based nano machining conducted on commercial AFM instruments. In particular, it is proposed to machine in this way nanostructures generated with any CAD software via the representation of tip path trajectories with G-code instructions. Such a representation can then be interpreted with a post processor at the interface of an AFM instrument. To demonstrate the validity of the proposed approach, it was implemented on a complex pattern. The results obtained open further research perspectives with respect to minimizing the sources of machining errors observed. Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/10985/7472 2013-01-01T00:00:00Z BROUSSEAU, Emmanuel ARNAL, Benoît THIERY, Stéphane MAYOR, J.Rhett NYIRI, Eric GIBARU, Olivier This paper presents a feasibility study, which aims to demonstrate the applicability of the CNC automation philosophy for the process of AFM probe-based nano machining conducted on commercial AFM instruments. In particular, it is proposed to machine in this way nanostructures generated with any CAD software via the representation of tip path trajectories with G-code instructions. Such a representation can then be interpreted with a post processor at the interface of an AFM instrument. To demonstrate the validity of the proposed approach, it was implemented on a complex pattern. The results obtained open further research perspectives with respect to minimizing the sources of machining errors observed.