The MEGAROB project will be more precisely dedicated to the manufacturing of large components such as airplanes and container-ships body parts or generator blades and masts for wind mills.
The main problems encountered when manufacturing large components are related to:
- The difficulty to maintain a high level of accuracy
- The need to move the parts from one site of the factory to the other in order to realise the different manufacturing operations
- The necessity to realise at least part of the manufacturing operations manually
Ultimately, these drawbacks have a negative impact on the competitiveness of the industry because of the increased processing time and the necessary investments in manufacturing equipments.
The development proposed within MEGAROB consists in developing a platform for the realization of such operations automatically with a high accuracy rate in positioning of ±0.216mm+0.5μm/m. This supposes a tolerance of ±0.4mm in a 100 meters long part. The targeted system will be composed of a spherical robot, mounted on a conventional simple structure, such as a crane. This robot can cover a very large area, thanks to the capacity of the overhead crane.
The main problem to overcome for such a system is to work accurately enough to fulfil the requirements of the products to be manufactured.
Indeed, a robot by itself has a limited accuracy. If it is also mounted on a translation system, such errors theoretically should increase exponentially, by simply adding more axes of movement, and especially to dramatically increased kinematics size of the system.
The aim of the project is therefore to split the working area of the full crane, into three-dimensional sectors, with a particular shape. Each sector becomes a working sector where the robot is located to perform the manufacturing or repairing tasks in that area. Once located, the exact position of the robot is acquired using laser tracker systems.
Several targets are placed at the base of the robot, with a setting of 3 spheres, whose position allows unambiguous definition of a coordinates system.
The tracker points in real time the main target, and once set in position searches the other two targets. With the information of the spatial coordinates of the targets, the mathematic algorithm will be developed to create the changing matrix between the relative and the absolute origin.
Once the robot is located, the information about its position will be sent to the High level control system that will adapt the CAM paths to the actual position. This way positioning errors are corrected and MEGAROB will adapt its behaviour and manufacturing plan for the new situation.
As a consequence, the proposed system will have an industrial robot working in vast areas without increasing its intrinsic positioning error.
Positioning deviations errors are very important in the industrial manufacture of small parts. If the scale of these deviations is maintained for large parts, the parts processed with this system will easily pass the quality requirements.
With this concept, the MEGAROB system will be able to manufacture and to repair parts or tools whose dimensions are above 10 meters long by performing milling, drilling, deburring, grinding, polishing, riveting, screwing, welding, painting, or quality dimensional control tasks, with applications in industrial sectors such as aeronautics, marine, renewable energy, construction and civil engineering, etc ….
Cooperation project: Small and Medium Scale / Total Budget: 4,3 M€ Grant: 2.7 M€ /
8 partners (4 countries) / Duration: 1/11/2012 to 31/11/2015