# A Prototype Mechatronic Device for Upper Limb Rehabilitation and Analysis of Its Functionality
## 4 Device Functionality
### Results from Functional Testing of the Device  
The prototype was tested with three participants aged 39, 67, and 68 years, comprising one female and two male participants. During a one-week testing period, none of the participants reported any issues with the application's functionality. The recorded data includes errors related to object selection and manipulation, as well as the time required to complete tasks. Figures 25-31 present the results of the initial evaluation. The appraisement assessment was conducted over a period of 14 days under three different device configurations (Appraisement--Round 1, Round 2, and Round 3, Figure 20a):  
* Appraisement--Round 1: All three arms of the device (storage module, right task module, and left task module) were aligned at a 0\({}^{\circ}\) angle. * Appraisement--Round 2: The storage module remained straight (0\({}^{\circ}\)), while the task modules were tilted outward at a 30\({}^{\circ}\) angle. Figure 23: Graphical user interface of the upper limb rehabilitation device. Windows: (**a**) exercise selection at the medium level, (**b**) report of a completed medium-level exercise. Figure 24: Graphical user interface of the upper limb rehabilitation device. Windows: (**a**) exercise selection at the hard level, (**b**) report of a completed hard-level exercise. * Appraisement--Round 3: The storage module remained straight (0\({}^{\circ}\)), while the task modules were tilted outward at a 60\({}^{\circ}\) angle. Figure 28: Results from the easy-level exercise module—Round 2. Figure 27: Results from the appraisements module—Round 3 (storage module aligned straight at a 0-degree angle, while the two task modules are tilted outward at a 60-degree angle). Figure 25: Results from the appraisement module—Round 1 (storage module and both task modules aligned straight at a 0-degree angle). Figure 26: Results from the appraisements module—Round 2 (storage module aligned straight at a 0-degree angle, while the two task modules are tilted outward at a 30-degree angle). Each module was equipped with two control buttons, which the user was required to press in any sequence. After each individual task involving the transfer of a designated object to the left or right container, the user was required to press a button. Failure to press the button triggered both visual and acoustic signals. Since the set duration and complexity of sessions could induce fatigue, arm length could also be modified mid-exercise to meet individual needs and ensure completion of the task. Three sessions were conducted daily with specific arm configurations:  
* Parallel (angle \(\alpha=0^{\circ}\))--Figure 25;
* Tilted outward at \(\alpha=30^{\circ}\)--Figure 26;
* Tilted outward at \(\alpha=60^{\circ}\)--Figure 27.  
In the graphs (Figures 25-27), it is evident that Participant No. 2 performed worse when the task modules were tilted outward. On Days 3, 7, and 11, they managed only three out of six successful button presses. The other participants (Nos. 1 and 3) demonstrated better consistency, with 5-6 presses per session. Figure 31: Results from the difficult-level exercise module obtained by Participant No. 3. Figure 29: Results from the difficult-level exercise module obtained by Participant No. 1. Subsequent tests were performed using a single arm configuration (\(\alpha\) = 30\({}^{\circ}\)). Figure 28 illustrates a graph based on the results obtained by participants completing tasks at the \"easy\" difficulty level. During these tasks, participants were required to place spherical objects into designated windows in the task container, utilising attachment No. 3 (Figure 10) and spherical objects (Figure 8). According to Figure 28, Participant No. 2 made approximately 50% errors across eight objects, showing only minor improvement, with their best performance being three errors. Participants Nos. 1 and 3 achieved significantly better outcomes: one error (Participant No. 3) and zero errors (Participant No. 1). Figures 29-31 present the error rates recorded during the 14-day exercise period.