PhD Thesis Proposal proposed by LCFC Department, Université de

PhD Thesis Proposal proposed by LCFC Department, Université de Lorraine Doctoral School IAEM N° Research Department: Laboratoire de Conception Fabrication Commande, EA 4495, Université de Lorraine. Title: Design and Control of a Parallel Wire Robot for Agile Handling of Parts on Manufacturing Line. Title in French: Conception et Commande d'un Robot à Câbles pour la manipulation dextre de pièces sur des chaînes de production PhD Supervisor: Professor Gabriel Abba Co‐supervisors: Associate Prof. Jean‐François Antoine, Associate Prof. Patrick Zatarrin Context of the work This work is part of an INTERREG project to create a new type of collaborative robot. The repetitive handling of heavy parts during a long time generates musculoskeletal problems for worker, which creates a great rise of health costs and physical risks are dissuasive for new workers. Thus the first objective of the work is to develop solution to help the worker with cobots. For expensive and fragile parts, where a decision has to be taken for each part (sorting or visual control) human work cannot be fully replaced by robots. Collaborative robots are a recent trend to allow the interaction of worker and robot in a safe way, worker brings his experience and robot assumes the work. For already installed manufacturing line, working space is often used and adding a new serial robot on the workshop ground is sometimes difficult. Using the ceiling to fix heavy machine is not always possible and it could be necessary to reinforce the structure. Parallel wire‐driven robot is a way to achieve the work with a light structure, with low modification of existing workshop. Subject description: As a definition of wire‐driven parallel robot, Merlet stated: “Wire‐driven parallel robot (WDPR) is a special class of parallel robot in which the rigid legs are replaced by wires. As for classical parallel robot, motion of the platform may be obtained either by changing the lengths of the wires (type 1) or having fixed wires lengths and modifying the location of the attachment points of the wires on the base (type 2). In the first case wire lengths may be modified by using either a coiling winch or by using a linear actuator with a pulleys system (Merlet, 2010). We may also distinguish completely restrained robot where the wires fully constrained the n d.o.f. of the platform (in which case the number of wire must be at least n + 1 (Ming et al., 1994)) and cable suspended robot with at least n wires, gravity playing the role of a virtual downward pulling wire. WDPR have been introduced in the 80's (Landsberger and Sheridan, 1985), (Miura and Furuya, 1984) as an alternate to parallel robot with rigid links. The foreseen advantages was less intrusive legs, a simpler mechanical structure (passive joints are eliminated) and potentially larger workspace for the type 1, as the amount of leg lengths variation may be much larger than with rigid legs. WDPR shares with classical parallel robots the ability to manipulate large load and to be energy efficient. But the major difference is that wires can be pulled but not pushed, which imposes an unilateral constraint: that must be checked. We will see that this constraint greatly complexifies the analysis of WDPR.” Arts et Métiers ParisTech - Centre d’enseignement et de recherche de l’Ecole Nationale Supérieure d’Arts et Métiers
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The cobot control is performed by a simple and user friendly interface. The user can change the Cartesian position of the robot, controller keeping a constant orientation of the robot or control the position and orientation of the whole. The robot is possibly under‐actuated. So positive constraints on the control are considered as well as solve a problem of minimizing forces on the cables. The best kinematics is sought to satisfy all constraints (design, control) and obtain the desired performance. A hybrid structure, composed on a wire driven plate and a few actuators fixed on it, can be considered. The aim of this thesis is to develop and control this hybrid structure. Security aspects may be taken into account. References Website of J‐P Merlet: http://www‐sop.inria.fr/members/Jean‐Pierre.Merlet/Cables/biblio_espace.html J‐P Merlet, Parallel Manipulators Applications—A Survey http://file.scirp.org/pdf/MME20120300008_25461121.pdf J‐P Merlet, Analysis and Optimization of a New Differentially‐Driven Cable Parallel Robot http://www.polymtl.ca/labrobot/pdf/JMR2015.pdf Johann Lamaury, 2013, Contribution à la commande des robots parallèles à câbles à redondance d’actionnement, PhD thesis. https://tel.archives‐ouvertes.fr/tel‐01021423/file/37511_LAMAURY_2013_archivage_cor.pdf Contacts: Jean‐François ANTOINE: jean‐francois.antoine@univ‐lorraine.fr Patrick ZATTARIN: patrick.zattarin@univ‐lorraine.fr Gabriel ABBA: gabriel.abba@univ‐lorraine.fr Candidate Profile The candidate must have a Master in automatic or robotic. An engineering degree would be appreciated. To apply, send a CV, Master scores, any publications and a motivation letter to: Gabriel Abba, gabriel.abba@univ‐lorraine.fr Limit date for the application: 2016, August 15 Employer: Université de Lorraine. More information of the academic partner can be found on: Website: www.lcfc.fr Employment contract Temporary employment contract of 3 years under PhD agreement with the Université de Lorraine Gross salary: around 24k€ gross annual Start date: 2016, September 1st Arts et Métiers ParisTech - Centre d’enseignement et de recherche de l’Ecole Nationale Supérieure d’Arts et Métiers
4 rue Augustin Fresnel - 57078 METZ CEDEX 3
Tél. : 03.87.37.54.30 - Fax : 03.87.37.54.31