Virtual inline compensation by single point-tracking in free-form bending

Free-form bending represents an attractive process for the manufacturing of structural components. Due to its kinematics-based working principle, a variety of geometries can be realised in the 3D-space featuring different radii, angles and bending planes. Nevertheless, the kinematic design of the bending head movement represents a complex task, and in order to obtain a part in the desired tolerance range a time-consuming trial and error procedure is the actual state of the art. The part is measured offline and compared to the target geometry after the bending operation, and the analysis of deviations is carried out to derive the compensated bending program. This is not only inefficient, but does not allow for compensating geometrical errors while the process runs. In this paper, a virtual inline compensation strategy based on single point-tracking is proposed. First, the process is modelled virtually and a single point on the component is tracked in space. Subsequently, the obtained tracking signals are presented and explained. Successively a kinematics adaption concept is shown and verified. On a virtual level the results show that the tracking of a single point on the geometry during the process can be used to compensate geometrical deviations in free-form bending.