In the scope of the proposed activity, a device for automated application of a riblet structure based on an existing prototype was to be developed and optimised. The applicator consists basically of a closed silicone belt with a micro structured outer side which imprints a UV-curing paint layer. The belt is led by a number of rollers two of which lay it partially onto the surface to be coated. In between a UV light source cures the paint so that the moving applicator leaves a riblet structure behind.

A riblet structure refers to longitudinal parallel grooves. By arranging this structure with its grooves in the direction of an oncoming flow on a body’s surface, the drag experienced by this body is reduced compared to a non-treated condition. For aircrafts, a reduction in drag means direct savings in fuel consumption and thus a lower impact on the environment as well as cost savings for the operator.

The proposal presented the task of designing and building the improved riblet application prototype for use on a robot-system. For this task, all available information on knowledge gained with the existing prototype was evaluated and supplemented with additional components. Main newly implemented tasks were the incorporation of suitable guiding measures for both the belt and the applicator along with dedicated sensors for guidance control and quality check of the riblet structure.

After the improved applicator is built a work package was dedicated to several robot-trials after which the applicator design undergoes an optimisation based on the trial results. In the end, together with a robot, the applicator applied a riblet structure on large scale components enabling it to be used on an industrial level.