Jean-Yves Hascoet
École centrale de Nantes
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Featured researches published by Jean-Yves Hascoet.
Journal of Manufacturing Systems | 1996
Suk-Hwan Suh; Jung-Hoon Cho; Jean-Yves Hascoet
For geometric accuracy, the problem of tool deflection should be resolved for 2-D finish-cut contour machining. This paper investigates a path correction method for the nominal path given by the part program. The significance of the deflection error is first shown by experiments, and a direct compensation scheme is proposed that evaluates and corrects the tool path based on an instantaneous deflection force model until the desired contour is obtained in the presence of tool deflection in actual machining. The method is distinguished from the previous approach based on geometric and cutting simulation and on feed rate adjustment via adaptive control. Further, the method can be viewed as a direct and active method toward net-shape NC machining. Simulation results show the validity and adequacy of the path-modification scheme under various cutting conditions.
Robotics and Computer-integrated Manufacturing | 1998
Jean-François Petiot; Patrick Chedmail; Jean-Yves Hascoet
Abstract In this paper, we intend to propose a method for minimizing the cycle time of robotic tasks by using an optimal scheduling of trajectory points: we consider functional points (welding or laser-cutting points on a car-body for example) that a robot has to reach. The problem is to order these points in such a way that the global cycle time is minimum. Originally, this scheduling problem is similar to the well-known travelling salesman problem. Among the algorithms used in combinatorial optimization, we have taken an interest in an original connectionist method called “the elastic net method”, initially presented in an euclidian two-dimension space. The method described in this article is adapted for robotic purpose. It has been tested in industrial cases and compared with a classical method in combinatorial optimization: the Little’s algorithm. The elastic net method is generalized to the specific case of robotics applications. The elastic net method is generalized in the case of non-redundant and redundant robots; we develop a simultaneous research of the optimal scheduling and of the optimal choice of the configurations of the robot for each functional point. The optimal scheduling of the points of a trajectory in the case of redundant robots is presented. We consider it to be the original contribution of this work. In the case of cluttered environments, the above algorithm is adapted by introducing a repulsion potential between the obstacles and the “elastic”. This leads to the simultaneous research of the optimal scheduling and of the free path planning. The method, using a new kind of algorithm, leads to original and reliable results for minimizing cycle time in robotics.
Computer-aided Design | 2012
Rafiq Ahmad; Stephane Tichadou; Jean-Yves Hascoet
Multi-axis machine production process optimization, automation and intelligence are the key codes of todays scientific community. Rapid decision and intelligence are becoming more important for precise and safe virtual and real production. Multi-axis CNC production is a high speed machining process that demands less human intervention and high intelligence, to deal with any uncomfortable situation regarding collisions. Current CAM softwares as well as CNC machines are able to detect collisions but are unable to avoid these collisions automatically. This paper aims to make the CAD-CAM/CNC multi-axis safe trajectory generation process optimal, intelligent and automatic, using vision based image processing by the Snakes and Ladders game analogy. Applying the Snakes and Ladders analogy on machine virtual scene (trajectory preparation) and real scene (during production) images gives promising methodology for safe and efficient trajectory generation while avoiding collisions named Snakes and Ladders Analogy for Production Trajectory (SLAPT). Our Rectangular Enveloped Safe and Efficient Trajectory (RESET) algorithm, based on the same principle of the SLAPT methodology is also discussed in this paper. Results include some applications of algorithms on virtual and real machine scene images for the safe and optimized trajectory of tools. This paper focuses on intelligence and optimization of 2D non-functional transversal trajectories of 2-axis machines for production and preparation processes as an initial effort towards the complex safe trajectory generation process (mill-turn).
Journal of Intelligent Manufacturing | 2016
Jae-Min Cha; Suk-Hwan Suh; Jean-Yves Hascoet; Ian Stroud
Manufacturing is changing. New ideas of control, the maturity of CAM techniques and computer technology have enabled the definition of an advanced machine tool control standard, STEP-NC. STEP-NC is one part of a larger manufacturing picture with links to different manufacturing applications using the STEP suite of standards. STEP-NC is the key to a door behind which there is a rich field of research on manufacturing techniques and opportunities for lean, intelligent and flexible manufacturing. The problem is to pass through that door. Many potential users are waiting for a lead from control developers. Control developers are waiting for market interest. Existing legacy machinery and investment in traditional machining add inertia. Instead of having a clear development path, manufacturing has become something of a Gordian knot waiting to be disentangled. New research projects are addressing these issues as well, but this paper takes a different route in showing how strategic planning can lead to adoption of the new techniques in a phased way, a so-called ‘Roadmap’. The contribution of this paper is the manner in which the overall task of implementation has been subdivided into tasks and phases to achieve the introduction of the new technology.
International Journal of Computer Integrated Manufacturing | 2013
Rafiq Ahmad; Stephane Tichadou; Jean-Yves Hascoet
Multi-axis high speed production technology importance and complexity is increasing with the increasing demand of its intelligence. Lack of proper automation and intelligence may cause collision risks, time delays and production interruption. Collision is an important problem for multi-axis machines because the current machine technology lacks the proper feedback communication process and hence a minor difference between a real and virtual scene may cause collision in real production. Similarly, minor operator mistakes and complexity of the Computer Aided Design or Manufacturing (CAD/CAM) process can cause collisions in virtual production simulations. Current CAM software and multi-axis machines are capable of detecting collision but are unable to provide safe paths intelligently for its avoidance. This paper uses image processing techniques and CAD/CAM data in order to define safe simulated trajectories for online/off-line virtual production extendible to real production. The 3D Rectangular Enveloped object Safe and Intelligent Trajectory (3D-RESIT) algorithm has been developed to generate safe and intelligent 3D transversal trajectories for virtual preparation by detecting and avoiding collision intelligently. The approach takes three images from the 3D machine model, interprets trajectories from the CAM (G-code), captures the trajectory and objects positions in 3D, detects collisions and provides many intelligent solutions to avoid the same collision process and finally selects the feasible solution. The final results are validated by applying the generated trajectories points back to CAM software simulations for verification.
Archive | 2009
Matthieu Rauch; Raphael Laguionie; Jean-Yves Hascoet
Modern manufacturing requires a flexible numerical chain of industrial products, in particular the relationships between CAD/CAM solutions and CNC. No longer can CNC controllers restrain their tasks at the execution of inflexible orders and choices made at earlier stages of the numerical chain. Thus, in a STEP-compliant environment, the CNC controller possesses a broad decision-making power to optimize the NC programming according to the machining equipment properties. The NC programming environment then has to face new challenges. In the first part of the chapter, an implementation method leading to STEP-NC advanced manufacturing is proposed. This approach is divided into three successive sceneries of STEP-NC deployment for progressive improvements. Industrial concerns can also use STEP-compliant applications with their current machining equipment. In the second part of the chapter, the STEP-NC Platform for Advanced and Intelligent Programming (SPAIM) developed at IRCCyN is presented. This platform controls current industrial machine tools directly from STEP-NC files, which benefits from this new data model. It also includes new tool-paths programming methods, such as pattern strategies for trochoidal milling and plunging tool-paths. The platform demonstrates the benefits of STEP-NC for industry and also forms a basis for future STEP-NC related research and validation.
20th CIRP Design Conference | 2011
Raphael Laguionie; Matthieu Rauch; Jean-Yves Hascoet
Multi-process manufacturing calls for various competences and expertise. STEP-NC object-oriented approach proposes to unify several manufacturing processes in a common data model. Furthermore, CNC controllers are fully integrated into CAD/CAM/CNC numerical data chain. Thus, next generation of CNC machine tools promises to be more open, intelligent and interoperable. This chapter first proposes a simulation and optimization model for multi-process manufacturing environments by using STEP-NC. Then, a practical implementation of the developed concepts is carried out on the manufacturing equipments of the laboratory.
Archive | 2014
Kelvin Hamilton; Jean-Yves Hascoet; Matthieu Rauch
This chapter contains a summary of the current state of the ISO data model ISO14649 for Numerical Controller also known as STEP-NC. It details the reasons and need for an industrial STEP-NC paradigm shift by showing the benefits that would be immediately realizable using currently available tools and knowledge. Specific focus is given to the SPAIM application as it is one of the most advanced STEP-NC enabling applications available today that allows realizing those benefits. In considering the future possibilities of STEP-NC and the need for continued implementation, four important and complex topics are addressed. These topics would enable an increase in: interoperability through hybrid manufacturing environments, manufacturing supervision and traceability, flexibility and efficiency with high knowledge and information transfer as well as production optimization and simulation in multi-process manufacturing. Finally, a brief synopsis of the systems and components necessary for machine migration to STEP-NC using the SPAIM enabling application is given.
International Journal of Computer Integrated Manufacturing | 2016
Rafiq Ahmad; Stephane Tichadou; Jean-Yves Hascoet
Complexity of multi-axis, multi-functional computer numeric control machine tools and high productivity requirements with high precision is increasing day by day. This enhances the growing importance of machine intelligence, automation and safety. Integration of different types of manufacturing process, for example, Mill-Turn is the need of modern technology but this integration also increases the profile of collision risks. The general context of this study is the multi-axis production process automation and intelligence (to work and react automatically) for safe tool movements. The work done during this research should appear in the form of machine intelligence for automatic safe and efficient collision-free tool trajectory generation without collisions. This study focuses on development of an intelligent approach for enhancing decision processes by providing automatic solutions to the collision problem. The main objective is to make machine vision control effective, that is, images or video processing, so that it can see activities regarding collisions and can react or command automatically for safe production. In the presence of obstacles, the proposed approach will provide decisions regarding trajectory correction and improvement. The proposed vision tool is able to take into account the evolution of the scene, such as the aspects of obstacle changes (shape, size or presence) during production. Results presented are based on automatic 2D traversal safe trajectory generation and correction in a virtual simulated but dynamic environment. The approach presented will be adapted to online collision problems on the shop-floor by integrating it with step-compliant data interface for numeric controls technology in the future.
Archive | 2005
Stephane Tichadou; Olivier Legoff; Jean-Yves Hascoet
In the context of tolerance allocation in process planning, our interest has focused onto manufacturing defects 3D modeling. This paper presents two approaches towards geometrical manufacturing simulation. The concept of small displacement torsor is used in order to model geometrical defects of part surfaces. The first approach uses a CAD modeler in order to extract the geometrical data for mathematical processing using a symbolic computational software. The model that we developed for manufacturing considers each manufacturing set-up as a single mechanism. A chart representation has been defined to express the geometrical manufacturing conditions of the process plan as a torsor chain. The second approach uses the features of an industrial CAD/CAM system in order to reproduce and industrialize this model. Then we carry out a virtual numerical metrology of the model thus obtained. Through examples, we present comparisons of numerical results from both applications. The approaches converge towards the same results. Finally we propose a comparison table which enables to identify the advantages of each of the two approaches.