Drone-based areal laser triangulation for the geometry measurement of local surface defects

• Applicant: Professor Dr.-Ing. Andreas Fischer
• Subject Area: Measurement Systems
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 541022266

Drones have access to hard-to-reach places and offer free payload for sensor technology. They are therefore already used for inspection and measurement tasks with low uncertainty requirements. However, the limited resources in terms of energy, mass, measurement time and installation space, as well as the constant movements and vibrations pose a challenge for precise measurements. Therefore, the goal of the project is to clarify the measurement capabilities of a drone-based areal laser triangulation measurement system for high-resolution geometry acquisition of local surface defects with extents from the millimeter to single-digit centimeter range. Accordingly, on the one hand the challenge is pursued to enable simultaneous areal laser triangulation measurements with a high point density, which is to be achieved with a diffractive optical element for the generation of parallel laser lines or a dot matrix. Furthermore, the measurement task requires a low measurement uncertainty <1 mm at a minimum measurement distance of 2 m for safety reasons. Therefore, according to the goal of the priority program, the drone measurement system consisting of the three elements sensor, signal processing, and communication will be considered holistically to maximize the sensitivity and the signal-to-noise ratio, and minimize energy consumption. In addition, different drone-based 3D registration methods for the single-shot measurement data will be investigated in order to significantly increase the image resolution with repeated measurements from different drone positions. In addition, experiments in the laboratory and in the open field will be used to quantify the disturbing influences of the flying measurement platform (vibration, movement) and of the environmental conditions (wind, temperature, sun) on the measurement result and to investigate effective compensation measures. Finally, the measurement uncertainty achievable with the drone measurement system will also be characterized in the context of limited system resources (space, mass, energy, time) and the metrological efficiency, i. e., the measurement quality achievable with different system resources, will be determined. The associated modeling of the measurement system thereby forms the basis for the creation of a digital twin to predict the measurement capabilities of scaled systems. This forms the basis for the second phase to investigate extended scaling possibilities of system resources, to clarify the measurement capabilities of cooperatively-acting swarm systems, and to solve the inverse problem (How many and which resources are required for a given measurement task?).

• DFG Programme: Priority Programmes
• Subproject of: SPP 2433: Metrology on flying platforms