# Design and Testing of Torveastro: An Outer Space Service Robot
## 7 Experimental Tests and Results  
Due to their characteristics, Dynamixel MX-64T actuators were chosen based on the results computed from the simulations. A LiPo 14.8 V 6200 mAh battery was supplied for the motor unit for the actuator to achieve the desired performance. A Raspberry Pi 4 was attached to a U2D2 Robotis interface as a microcontroller. Using 3D printing technology, a motor unit was created for preliminary testing. On the motor unit's fixed part, a Dynamixel MX-64T was placed, and its rotating section was attached to its shaft. In the movable section, a second Dynamixel MX-64T acted as a preliminary load. In order to test the behavior and performance of the designed prototype, the motor controlling the rotation was set to concurrently execute the same simulated motion. To evaluate the experiment's mobility, a marker was placed on the moving platform, and an external camera tracked the motor unit as it moved. Figure 13 shows the experimental procedure. The red trajectory and blue angle depict the movements of the platform throw marker as recognized by the Kinovea software. Figure 14 reports the results of the motion analysis previously described. Figure 14 depicts the effects of the provided motion, with Figure 14a depicting the angular displacement and Figure 14b showing the related angular velocities. Motion began 1.32 s after  
Figure 12: Simulation results for the limb simulation: (**a**) Linear displacement input, (**b**) Computed Forearm COM X displacement, (**c**) Computed torque for arm motion, (**d**) Computed torque for forearm motion. Figure 13: Motor unit experimental test: (**a**) Starting position, (**b**) Final position. the recording began. In 5.42 s, the rotating portion turns up to 174.51 degrees. After a 1.37-s delay, the actuators reverse orientation and return to 0.00 degrees 7.90 s later. Two motion steps with opposing velocity directions are shown in Figure 14b to demonstrate the specified motion. The first section of the angular velocity graph depicts the ascent phase, which peaks at 80.76 at second 1.55. Starting at second 5.42, the section reaches its maximum angular velocity of \(-\)94.83 s per second at second 7.78. Comparing simulation results to those of this early testing reveals that simulation outcomes properly represent the simulated environment. Consequently, the suggested solution is viable, and the whole prototype may be built for additional testing. Using the same hardware to assess a prototype of the limb with a 48 mm pulley, 1.38 degrees of actuator rotation were measured to obtain the same simulated displacement. To monitor the mobility of the experiment, a marker was put on the arm and forearm's proximal projection of the Center of Mass (CoM), and an external camera caught the movement of the whole arm. Figure 15 illustrates the experimental method. The blue and green trajectories represent the arm and forearm motions of the markers, as identified by the Kinovea software. Figure 14: Motor unit experimental test results: (**a**) Angular displacement, (**b**) Angular velocities. Figure 15: Full limb experimental test: (**a**) Starting position, (**b**) Final position. As shown in Figure 16a, the forearm projected CoM travels a maximum distance of 8.52 cm along the \(X\) axis, perfectly reproducing the simulation results. Figure 16b displays the related velocities caused by the input motion; the forearm achieves a maximum velocity of 9.45 cm/s at second 1.40 while maintaining an average velocity of 2.36 cm/s. All experimental test results are consistent with the aforementioned prototype simulated design. In order to simultaneously move the nine actuators of the three limbs of the prototype, a preliminary basic motion control algorithm was developed. The motors were evaluated on the test platform while performing multiple tasks concurrently. As reported in Figure 17, the entire prototype was manufactured and assembled for the terrestrial motion demonstration whereas the control software was further implemented as duly designed.