## 3 Experimental Results
### Experiment on the Accuracy of the Pose Estimation System  
The accuracy of the pose estimation system plays an important role for the robot arm to correctly pick up the stamping workpiece. Therefore, the experiment in Section 3.1 measures the accuracy of the pose estimation system and focuses on the error range between the estimated distance and the actual moving distance. All of the translation and rotation axes have to be involved in this experiment. The experiment has two sub-experiments, where the first one examined each individual 6-axis X, Y, Z, RX, RY, and RZ error, and the other checked the repetition of the pose estimation system. Figure 7: Initial positions of dynamic scanning region and robot gripping system on the conveyor. Firstly, the three translation axes \(X,Y,Z\) errors are considered. As shown in Figure 8a for the \(X\) and \(Y\)-axis, the workpiece is initially placed next to the base which is considered to be the reference position; afterward, place a block next to the base which will enable the workpiece to move a distance of 60 mm (width of the block is 60 mm). Then compared to the reference position, the workpiece is moved 60 mm (the new position that needs to be measured); continue the experiment with other distances of 120 mm, 180 mm, and the other direction of \(-\)60 mm, \(-\)120 mm, \(-\)180 mm. Figure 8b displays the experiment for \(Z\)-axis. Similar to the experiment of the \(X\) and \(Y\)-axis, this experiment also uses a block to move the workpiece but in the vertical direction (\(Z\)-axis) and the base now is the worktable. The experiment is carried out by using a block with height of 25 mm. The distances of experiment are 25 mm, 50 mm, 75 mm, 100 mm, 125 mm, and 150 mm. Both in the reference and measured position, the workpiece point cloud is modeled for later recorded the error between the real distance and estimating distance. Now, considering the rotation axes \(RX\), \(RY\), and \(RZ\), the experiment setup for these axes is shown in Figure 9. The worktable is now recognized as the base and the reference position is where the workpiece is placed on the worktable. The experiment used the BOSCH rangefinder (Bosch, Germany) to estimate the angle. For the reference position, the rangefinder shows 0\({}^{\circ}\). Thereafter, the workpiece is rotated by placing a block under its side. Now, the new position angle will be shown on the rangefinder. The experiment was conducted with the angles of 30\({}^{\circ}\), 20\({}^{\circ}\), 10\({}^{\circ}\), \(-\)10\({}^{\circ}\), \(-\)20\({}^{\circ}\), and \(-\)30\({}^{\circ}\) for the \(RX\) and \(RY\) axes and 10\({}^{\circ}\), 30\({}^{\circ}\), 45\({}^{\circ}\), 60\({}^{\circ}\), 75\({}^{\circ}\), and 90\({}^{\circ}\) for the \(RZ\)-axis. Figure 8: Setup of standard positions for different estimation poses of the dynamic workpiece using a predetermined dimension block for (**a**) the \(X\)-axis and \(Y\)-axis and (**b**) the \(Z\)-axis. The method of the pose estimation system of this study is shown in Figure 10a-f for the three translation axes of \(X\), \(Y\), and \(Z\) and the three rotation axes of \(RX\), \(RY\), and \(RZ\). Similar to the description of the experiment setup above, the camera generates point clouds of the workpiece in both reference and measured positions to create the reference and measured cloud, respectively. In the figure, the blue point cloud is the reference point cloud, and the green point cloud is the cloud that needs to be measured for distance and angle. Each sub-experiment focuses on one axis in the total 6-DoF, and the estimated result is then compared with the real distance (or angle) to find the error. As shown in Figure 11, the translation error of the pose estimation of this study is considered to be reasonable and can be used in practical applications.