# Impact of a Robot Manipulation on the Dimensional Measurements in an SPC-Based Robot Cell
## 3 Materials and Methods
### Measurement Scenarios
The sequence after the individual measurement is as follows. The robot approaches the object from a distant point outside the Equator working area, grasps it, moves to a displaced position, releases the object, and moves away to a distant point outside the Equator working area. Then, the robot approaches the object in a displaced position, grasps it, and inserts it into a measuring position in the fixture. Scenario 7 is the total removal of the object from the fixture compared to scenario 3 to 6. After grasping the object in the fixture, the robot removes the object and moves outside the Equator's working area. In previous scenarios (3 to 6), the object was displaced (relatively small translations or rotations) from the measuring position and still located in the fixture. In scenario 7, these displacements were more significant, and the object is moved outside the fixture and the Equator's working area, as well, i.e., total removal. One new robot gesture is introduced in scenario 8. Namely, in some measurement or object positioning variations, an intermediate mechanical fixture is introduced, in most cases, with the aim of re-grasping the object in a different orientation (from vertical to horizontal or from horizontal in vertical). To investigate these situations, picking and placing to the re-gripping position in a workspace is added in scenario 8 to the previous total removal from a fixture. After the object's placement in the re-gripping fixture, the robot makes a release and changes its orientation, followed by a new grasp (in horizontal orientation) and positioning in the measurement fixture in the Equator. \begin{table}
\begin{tabular}{l l l} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**Measurement Scenario**}} & \multicolumn{1}{c}{**Description of Scenario**} & \multicolumn{1}{c}{**Measurement Method Used**} \\ \cline{2-3}  & **Magnet** & **PKR** \\ \hline Scenario 1 & No robot manipulation, measurement capability of Equator. & TTM, SM, SM+ & TTM + SM \\ Scenario 2 & Grip and release. & TTM, SM, SM+ & TTM + SM \\ Scenario 3 & Grip and translation. & TTM, SM, SM+ & TTM + SM \\ Scenario 4 & Grip and rotation. & TTM, SM, SM+ & TTM + SM \\ Scenario 5 & Grip, rotation, and translation. & TTM, SM, SM+ & TTM + SM \\ Scenario 6 & Grip, translation, and release. & TTM, SM, SM+ & TTM + SM \\ Scenario 7 & Total repositioning. & TTM, SM, SM+ & TTM + SM \\ Scenario 8 & Regripping. & TTM, SM, SM+ & TTM + SM \\ Scenario 9 & Complete automated measuring cycle, measurement capability of ARC. & TTM, SM, SM+ & TTM + SM \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Short description of nine robotized scenarios for an investigation of the robot’s influence on the capability of the measurement process \(C_{p}\) with used measurement methods in Equator gauge. For the Magnet object, three different measurement methods were used (touch-triggering method (TTM), scanning method (SM), and scanning method with additionally increased sampling points (SM+)); for the PKR object, only a combination of TTM and SM was used. The last scenario, scenario 9, is equal to a complete, automated measuring cycle, starting from picking an object from the pallet, re-gripping from a vertical to a horizontal orientation, inserting the object into the fixture, measuring with the Equator, removing the object from the fixture, re-gripping back from the horizontal to the vertical orientation, and placing the object back at starting position in the pallet. The compound robot manipulation operations from the basic operations are collected in Table 2. Operations involving precise movements (e.g., object insertion or object removal) and movements in constricted spaces involve linear movements, while operations that are not spatially constrained involve joint motion type. Correspondingly, velocities and accelerations in spatially unconstricted motions are significantly higher compared to constricted motions. The first four operations (approach, retract, insertion, and removal) vary according to the selected scenario.