# A System for Robotic Extraction of Fasteners
## 4 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Target** & **Successful** & **Successful** & **Image** & \multicolumn{3}{c}{**Coordinates (mm)**} & **Confidence** \\
**Number** & **Extract FP** & **Extract SP** & **Number** & **x** & **y** & **z** & **(0.00–1.00)** \\ \hline \multirow{2}{*}{\(1\)} & \multirow{2}{*}{X} & & First & 418.38 & \(-\)402.66 & 2.63 & 0.28 \\ \cline{3-6}  & & & Second & 417.48 & \(-\)402.96 & 2.07 & 0.53 \\ \hline \multirow{2}{*}{\(2\)} & \multirow{2}{*}{X} & & First & 387.57 & \(-\)403.15 & 10.12 & 0.85 \\ \cline{3-6}  & & & Second & 388.12 & \(-\)402.58 & 10.62 & 0.88 \\ \hline \multirow{2}{*}{\(3\)} & \multirow{2}{*}{X} & & First & 359.59 & \(-\)462.72 & \(-\)0.39 & 0.82 \\ \cline{3-6}  & & & Second & 357.83 & \(-\)463.26 & 1.03 & 0.79 \\ \hline \multirow{2}{*}{\(4\)} & \multirow{2}{*}{X} & & First & 356.65 & \(-\)372.46 & 11.23 & 0.55 \\ \cline{3-6}  & & & Second & 357.01 & \(-\)373.06 & 12.78 & 0.63 \\ \hline \multirow{2}{*}{\(5\)} & \multirow{2}{*}{X} & & First & 357.51 & \(-\)401.24 & 22.72 & 0.80 \\ \cline{3-6}  & & & Second & 358.85 & \(-\)402.51 & 20.53 & 0.36 \\ \hline \multirow{2}{*}{\(6\)} & \multirow{2}{*}{X} & & First & 358.90 & \(-\)432.23 & 11.51 & 0.56 \\ \cline{3-6}  & & & Second & 358.89 & \(-\)432.25 & 11.51 & 0.56 \\ \hline \multirow{2}{*}{\(7\)} & \multirow{2}{*}{X} & & First & 328.15 & \(-\)402.30 & 11.62 & 0.61 \\ \cline{3-6}  & & & Second & 328.12 & \(-\)401.88 & 10.69 & 0.88 \\ \hline \multirow{2}{*}{\(8\)} & \multirow{2}{*}{X} & & First & 297.11 & \(-\)403.26 & 0.14 & 0.47 \\ \cline{3-6}  & & & Second & 298.83 & \(-\)402.65 & 3.63 & 0.76 \\ \hline \multirow{2}{*}{\(9\)} & \multirow{2}{*}{X} & & First & 358.31 & \(-\)340.42 & 3.49 & 0.32 \\ \cline{3-6}  & & & Second & 358.27 & \(-\)340.37 & 3.49 & 0.32 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Bulk run data using two-stage imaging with DCNN. the screwdriver slipping away from the center of the cross-recessed screw when attempting to spin into the correct orientation after the force sensor detects contact with the part. This is related to inaccuracy with the deprojection system, as trying to seat the driver off-center would make the screwdriver re-orientation process more likely to slip. These limitations combined to prevent the testing and extraction of smaller-diameter cross-recessed fasteners. The stereoscopic camera's vision system introduced errors in its deprojection model, attributable to an inherent 2% depth sensing error specified by the manufacturer and the inability to image objects closer than approximately 280 mm. An empirical compensation method was applied to enhance target positioning accuracy. Testing was conducted to derive a 3D calibration curve, which compensated for the X and Y distances (relative to the camera imagers) as a function of deprojection distance. This curve was developed for the camera system's valid operational range (280-500 mm), where the DCNN model demonstrated reasonable target detection confidence. The calibration curve was constructed using three targets arranged vertically on a placard with known dimensions. The placard was evaluated at six positions across four depths relative to the RGB imager. Data were collected for 15 min at each position to capture a broad range of discrete detection coordinates. The variability in the position of the tool center point defined on the electric screwdriver was estimated to be between 0.5 and 1.0 mm, which limited the overall process testing to the larger CRS targets discussed in this work. The inconsistency introduced as the tool changes orientation would necessitate a screwdriver with less variability in the chuck design, which secures the bit. This issue warrants further investigation for a more robust tooling design. Overall, the failures introduced by the prototype tooling and imaging system could be mitigated through a process design incorporating an iterative imaging technique, albeit at the expense of higher cycle times and lower first-pass yield.