Nahfeldnavigation unbemannter Flugsysteme zur Inspektion von Infrastrukturen
- Close range navigation of remotely piloted aircraft systems for infrastructure inspection
Eschmann, Christian; Moormann, Dieter (Thesis advisor); Alles, Wolfgang (Thesis advisor)
Dissertation / PhD Thesis
Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2016
As a result of complex and aging structures an ever increasing number of infrastructures prone to damage exists, especially in industrialized countries. At the same time there is a lack of adequate and automated methods for the inspection and monitoring of these infrastructures due to the exposed location as well as the specific design of these objects. On the basis of current developments in the field of robotics, new possibilities are emerging for the use of Remotely Piloted Aircrafts (RPA), which in the case of airborne inspection can be used as flying sensor platforms allowing a less time-consuming data acquisition while saving costs for personnel and materials. The prerequisite for a safe and economical application is the existence of a precise as well as reliable navigation method as a basis for reproducible results of such automated inspection systems.This thesis discusses the safe and defined navigation procedures for the approach, positioning and control of RPA systems in the close vicinity to structures. At first, five airborne non-destructive testing procedures are examined hereto, which are basically available for integration into RPA systems. Based on the explanations of the pursued inspection process, the requirements for the entire system are then formulated. In order to be able to assign a specific RPA platform to the navigation method, a system evaluation is carried out for various RPA configurations based on their characteristics, which concludes with the selection of an appropriate RPA system for the final validation of the navigation method. Equivalent to the RPA, three measuring methods basically available are presented and evaluated with regard to their usage as airborne navigation sensors. The final sensor technology is then determined in a direct comparison followed by the selection of a specific navigation sensor. The selected sensor is subjected to an in-depth evaluation providing information about the exact, individual sensor behavior. The knowledge of these sensor characteristics is essential for the development of a complex sensor model. The core aspect of the close-range navigation is first formulated in a general approach, which is then subsequently adapted to the previously identified inspection criteria as well as the selected navigation sensor. In a next step the integration concept is presented which specifically contains the modeling of the position control on the basis of flight modes as well as the modeling of a complex LiDAR sensor model based on the evaluation results. The integration concept is evaluated in a subsequent simulation using an individually created scenario under laboratory conditions. Finally the basic function of the indicated close-range navigation method is demonstrated during flight tests using a real RPA system.