French manufacturing companies occupy an economic sector that is constantly changing. In order to better meet their customers' expectations and market pressures, they must be innovative and willing to invest in modernizing their plants. However, it is not always possible to make major investments in research and development, particularly for SMEs. It is in this context that technological research institutes were launched in 2012 in order to contribute to improving the competitiveness of strategic industrial sectors in France. One of them, the Institut de Recherche Technologique (IRT) Jules Verne,was set up in Nantes.
The IRT Jules Verne is a shared industrial research center working with many French industrial partners. The work carried out by the IRT Jules Verne, the only Technological Research Institute dedicated to manufacturing in France, is part of industrial research with objectives of accelerating innovation and technology transfer to factories. While proposing technological breakthroughs in manufacturing processes, the IRT Jules Verne uses a collaborative approach to meet the challenges of industrial sector markets.
Performance study – parallel cable robot
Recently, the IRT Jules Verne has developed a new robot, belonging to the category of parallel cable robots (RPC). These are robots that move their effector/work tool via 4 to 8 cables, connected to a fixed support. A relatively rare technology outside research laboratories, the use of the latter in an industrial context has yet to be demonstrated. In order to make this demonstration, a team of researchers from the IRT had to put the prototype to the test.
Unlike the traditional on-shelf robot, it was impossible for researchers to consult the technical specifications to know its repeatability. This type of information had to be clarified through experimentation and an in-depth study of the robot's performance. The IRT team therefore set out in search of a reliable measurement tool that would allow them to accurately measure the robot's behavior and estimate its absolute accuracy, repeatability, as well as drift over time.
Requirements for flexibility and accuracy
In order to complete this project satisfactorily, it was necessary for the researchers to find a metrological solution offering superior flexibility, accuracy and efficiency. Since the tests were to take place in the IRT technology hall, the considerations of simplicity and cost were also of great importance.
Tests were initially done with a high-end virtual reality system, but since the device was not precisely designed for this type of use, it was not able to offer a measure valid enough to be used as ground truth. Other avenues were also explored, such as the use of a laser tracker system. Although the speed and accuracy of measurement were adequate, the cost and complexity of use were not compatible with this research project.
In search of the ideal solution
IRT researchers finally decided on Creaform's C-Track system because of its submillimeter measurement accuracy and accessible cost. With a measurement frequency of up to 6600 3D points per second and a volume measurement of 9.1 to 16.6 m3, this technology proved to be the ideal solution for this project. In addition, the ability to move the C-Track without having to recalibrate everything proved to be a definite advantage. This product from Creaform allowed the researchers to obtain the ground truth and measure the position of the robot's effector in its entire volume of work.
Nicolò Pedemonte,R&D Engineer in Robotics at IRT Jules Verne, says that the whole team is very satisfied with these first experimental validation results and the use of C-Track as a whole. "Although it is difficult to define precisely the savings we have been able to make, it is interesting to point out that we can estimate that 50% of the time saved," he says, before adding that "if we had used another measurement system, the cost in time and cash would have been prohibitive."
About IRT Jules Verne
The Jules Verne Technological Research Institute is a shared industrial research center dedicated to advanced production technologies. Focused on the needs of strategic industrial sectors – aeronautics, automotive, energy and naval – its team carries out research in collaborative mode by combining itself with the best industrial and academic resources in the field of manufacturing. Together, they are working on the development of innovative technologies that will be deployed in factories in the short and medium term on five major themes: forming and preforming processes | Assembly and Welding Technologies | Additive Manufacturing Processes | Mobility in the | Industrial Space Flexibility of production. To offer global solutions up to scale 1 demonstrators, the IRT Jules Verne relies on a set of exclusive equipment.
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