## 7 Experimental Setup and Testing  
In the beginning, the 3-RRS parallel manipulator must be prepared to be attached to the KUKA KR6 R900 serial robot. It was designed using SOLIDWORKS software and implemented using a 3D printer. Moreover, it was provided with a thrust ball bearing at the passive joint (\(C_{i}\)) to prevent friction between the active link and the passive link. Furthermore, it will support the axial load on the joint, while at the spherical joint (\(B_{i}\)) a ball joint with a neodymium N-35 magnet was used for flexibility of movement, easy installation, and fast replacement with other end effectors, as shown in Figure 11. Finally, the 3-RRS was supported with three DYNAMIXL servomotors (XL-430), which provide many features, such as serial communication, PID control, feedback of position angle, speed, temperature, and load. Figure 10: Octagon Path. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline \hline
**Point** & \(\theta_{1}\)\({}^{\circ}\) & \(\theta_{2}\)\({}^{\circ}\) & \(\theta_{3}\)\({}^{\circ}\) & \(\theta_{4}\)  
Figure 12 shows the experimental setup, which contains the 3-RRS parallel robot mounted in the end effector of the serial manipulator KUKA KR6 R900. Then, the KRC4 KUKA controller was prepared and installed with KUKAVARPROXY, which can read or write variable data on the KUKA manipulator [33]. Further, it converts the controller to a server that can host up to ten clients. The KRC4 controller is connected via TCP/IP with the Raspberry Pi (client computer), which is provided with a Python code that can send the required joints to the KUKA controller and Arduino, via USB connection. Furthermore, Figure 13 describes the experimental process required to control the hybrid manipulator and follow the required path, where \(\theta_{hr}\), \(\theta_{sr}\), and \(\theta_{pr}\) represent the required joint angles for the hybrid manipulator, the KUKA robot, and the 3-RRS parallel manipulator. Here, \(\theta_{hf}\), \(\theta_{sf}\), and \(\theta_{pf}\) represent the joint angle feedback for the hybrid manipulator, the serial KUKA serial robot, and the 3-RRS parallel manipulator, respectively. The Python program includes the KUKA messenger protocol to send data (read/write) to the KUKA KRC4 controller through KUKAVARPROXY, while it has a 3-RRS messenger, which is responsible for communicating with the 3-RRS parallel manipulator through ARDUINO. Additionally, the KRL (KUKA Robot Language) program can actuate the KUKA robot from the data received via the KUKAVARPROXY. Finally, there is a digital input/output interface between the KUKA controller (KRC4) and the 3-RRS controller (Arduino) for synchronization between the KUKA manipulator and the 3-RRS manipulator. Figure 11: KUKA Kr6 R900 manipulator installed with 3-RRS. Figure 14 shows the actual laboratory experimental test that follows the octagon path following the specified eight points (A, B, C, D, E, F, G, and H), mentioned above from the workspace. Then, by recording the position \((x,y,z)\) and orientation of the points (A, B, C, D, E, F, G, and H), as shown in Table 6, and the angle of the serial-parallel manipulator joints, as shown in Figure 15, we found that the new SPHM follows the selected path precisely and correctly ([[https://clipchamp.com/watch/76B0d4](https://clipchamp.com/watch/76B0d4) mMP69]([https://clipchamp.com/watch/76B0d4](https://clipchamp.com/watch/76B0d4) mMP69) (accessed on 10 Septmber 2022)). The data were matched with the previous data recorded from the graphical model. Figure 12: Experimental Setup Diagram. Figure 13: Experimental Setup Chart. Figure 14: Experimental Setup of the Serial-Parallel Manipulator.