## 6 Experimental Tests
### Experimental Results and Discussion  
Figure 11a,b elucidates the experimental implementation performing a continuous passive motion of the finger F/E. The solid red curve demonstrates the DIP phalanx workspace trajectory caused by FWRMS, and the solid black curve illustrates the DIP joint trajectory workspace without the FWRMS. In contrast, the yellow highlighted value presents the DIP joint's current position in the set coordinate frame. It is easy to confirm that the actuated DIP phalanx movement caused by FWRMS is within the natural functional trajectory workspace of the DIP phalanx; without FWRMS, and they are closely associated towards each other. Moreover, further analysis was carried out to study the finger joints' ROM (DIP, PIP, and MCP), driven by FWRMS to perform a finger F/E. As illustrated, Figure 11c,d, the MCP joint achieved 56 degrees, 67 degrees by PIP, and 50 degrees by DIP. These ranges are considered within the normal functional grasping range of motion of the index finger. Besides, we have also accomplished a graphical description by analyzing the video data used for both the opening and closing phases. Figure 12a,b shows a comparative analysis between; (1) the desired DIP phalanx displacement, which plotted a solid blue curve; (2) the actual DIP phalanx displacement induced by FWRMS, which is plotted by solid orange. It is straightforward to understand that the participant performed a finger flexion and extension two times, and the plotted displacements are in both vertical and horizontal orientation, respectively. Figure 12a plots the horizontal X axis, while Figure 12b describes the vertical displacement in the Y-axis. Figure 11: A real-time experimental setup of the index finger’s workspace trajectories measurement: (**a**) Index finger fixation actual range of motion (ROM) angle, workspace trajectory, and position caused by FWRMS. (**b**) index finger extension actual (black curve) and desired (black curve) workspace trajectory. (**c**) Index finger joints (MCP, Distal Interphalangeal PIP, and Proximal Interphalangeal DIP) grasping ROM. (d) the overall grasping angle of the index finger. Moreover, we can also observe that FWRMS drives 80 mm of total displacement at the horizontal axis to open and close the index finger and \(-\)39 mm displacement at the vertical axis; these displacements values are considered within the normal functional range of the index finger. Besides, the actual guided trajectory corresponds to the planned desired trajectory, and all the finger joints (DIP, PIP, and MCP) traveled concurrently without any movement discomfort. Accordingly, the results indicate that the motion of the finger rehabilitation design is stable. However, it can be observed that the actual and desired displacements of the DIP phalanx have a small percentage of error during the execution of the movement. It is worth noting an error percentage, about 0.874% error at the vertical axis and 1.257% error at the horizontal axis. The error rates are limited mainly by the friction between the external threads of the lead screw and the internal threads of the nut and the vibration caused by the movement. However, these small errors do not influence the CPM rehabilitation characteristics and the proposed device's performance. Similar to the previous method, the wrist motion was studied and analyzed with and without the FWRMS device. In this experiment, we selected the desired ROM for wrist F/E to be (0\({}^{\circ}\)-70\({}^{\circ}\)/0\({}^{\circ}\)-60\({}^{\circ}\)); these degrees were chosen to be within the wrist's normal  
Figure 12: Continuous passive motion rehabilitation experiment of s typical finger DIP flexion and extension joint displacement;(**a**), horizontal displacement; (**b**), vertical displacement. ROM. Passive markers and angle measurement markers were located using the motion capture system on the targeted joint to acquire these ROM angles and trajectories; After the therapy started, the system moved smoothly according to the preselected ROM with low rpm.