## 3 Experiments and Discussions
### Evaluation in Real-World Use-Case  
The presented concept is evaluated at a typical rotor blade form, which features a length of 11 m. Due to space limitations of the experiment environment, only the tip of the form is used throughout the experiment. Figure 13a shows the 3D model of the tip. The tip has the dimensions 2.0 \(\times\) 0.8 \(\times\) 0.9 m\({}^{3}\) (LxHxW). Figure 13b,c show the real-world form equipped with glass fiber mats and a setup for vacuum generation. Figure 12: Path potentials of a path related to a start-goal-position tuple \(t\in T_{SC}\). Start position in red and goal position in green. (**a**) Dijkstra; (**b**) DijkstraZone; (**c**) A*; (**d**) A*Zone. Figure 14a shows the analyzed workspace of the used Universal Robot UR5 displayed as a cut in the x, y-plane of the manipulator coordinate frame \(R\). Since the end-effector will be downward oriented most of the time during inspection and accordingly to [29], the used geometric primitive to analyze the workspace is a downward facing hemisphere. Each analyzed voxel has the edge length of 50 mm. Figure 14b shows the same cut, with a threshold at 50% reachability applied. The chosen suitable workspace area consists of two layers in z-direction to cover the curved shape of the blade tip form. The area is shown in Figure 14c and of size: 0.45 m in x-direction, 0.7 m in y-direction, and 0.1 m in z-direction of the coordinate system \(R\). In addition, the so-called max reach value \(max_{reach}\) of the mobile manipulator is calculated. The \(max_{reach}\) symbolizes the maximum distance the manipulator is able to reach  
Figure 14: Workspace analysis of the manipulator for the inspection task at the corresponding height. (**a**) Cut through the x,y-plane; (**b**) Cut through the x,y-plane with reachability threshold of 50%; (**c**) chosen workspace area at height \(z_{\text{r}}=0.1\) m.  
Figure 13: Rotor blade forms. (**a**) 3D model of the tip of the rotor blade form; (**b**) rotor blade form used in the real-world experiment (side view); (**c**) rotor blade form used in the real-world experiment (top view). into the workpiece alongside the robot coordinate system \(R\). The calculation is given in Equation (6):  
\[max_{reach}=D_{MW}-(d_{RPF}+d_{PFW}), \tag{6}\]  
where \(D_{MW}\) is the distance between the origin of \(R\) and the reachable voxel, which is located at the maximum distance alongside the x-axis of \(R\). The distances \(d_{RPF}\) and \(d_{PFW}\) depend on the hardware setup and the minimum safety distance between the platform and the workpiece. The distance \(d_{RPF}\) describes the distance between the origin of \(R\) and the front of the mobile platform. The distance \(d_{PFW}\) describes the safety distance between the front of the mobile platform and the workpiece. Based on the method presented in Section 2.3.4, the workpiece is segmented in in-spectable subsegments taking the maximum reach \(max_{reach}\) of the hardware setup into account. Figure 15a shows the colored subsegments. Figure 15b shows the corresponding poses of the mobile platform as black arrows for each subsegment. Figure 15c shows the mobile manipulator executing the scan process at a subsegment of the work piece. At each local subsegment, the surface reconstruction (cf. Section 2.3.1) is executed. Therefore, an RGB-D camera provides a point cloud of the work piece. A crop box filter removes all points, which are related to the ground or the robot itself. In the next step, a HSV filter is applied to the remaining points to remove points related to the yellow corner tape of the vacuum setup (cf. Figure 15c). The resulting point are clustered by their Euclidean distance to determine the points belonging to the scanning surface. A down sampled version of the resulting point cloud is used for the surface reconstruction. Figure 16 shows the complete pipeline for a point cloud captured at a local subsegment. The waypoint generation (cf. Section 2.3.2) is based on the surface reconstruction.