## 2 Materials and Methods
### Testing Procedure  
The first phase of testing was a laboratory procedure, realized without the patient. Initially, the prosthesis was connected to the power source--a power bank--via USB cable (Figure 18).  
During that phase of tests, sample data were recorded. The prosthesis was tested by the researchers, by moving it around in various random patterns and applying various forces, simulating resting on handlebar, static loading (slight bending and compression), and dynamic loading (slight hitting). To generate the visualization of the data, MATLAB software was used. After confirming proper recording of sensor data, further tests were planned and realized.  
The second phase of testing involved working with the patient, who volunteered to take part in the experiments (his informed consent was obtained, and the ethical committee approval was gained prior to the studies). This testing stage consisted of fitting tests, where the prosthesis was tested by the patient for comfort, weight, and general fit. It was also compared to a purely mechanical prosthesis, to check if adding the electronic components influenced the use comfort and easiness.  
In the next stage of patient testing, the patient was invited to perform tests on the actual device. An electric scooter was used as a reference vehicle. In the first attempt, the  
Figure 17: Structure of the data file.  
Figure 18: Prosthesis during laboratory tests with power source connected.  
patient wore the prosthesis and tried it with the vehicle, to check if everything is correct mechanically. Then, after slight modifications were introduced to the angular position of the end effector (to adjust the prosthesis for the specific vehicle, used by the patient for the first time), the patient performed actual testing with data recording. It consisted of three separate tests:  
1. Static test with up-down movement of the prosthesis towards the vehicle handlebar (Figure 19);
2. Static test with right-left movement of the prosthesis along the vehicle handlebar (Figure 20);
3. Dynamic test that required to ride along a straight route, of approximately 25 m, but the patient was asked to drive in a circular manner (simulating manoeuvring around obstacles).  
During both static and dynamic tests, data sets were recorded by the prosthesis sensors. These data sets, similarly, as in the case of laboratory tests, were visualized using MATLAB and compared, to check if the recordings match the actual course of patient's movement.  
It is important to mention here, that these tests were focused on proper gathering of diversified data from the prosthesis sensors. The functions of the prosthesis and various aspects of bicycle riding, such as turning, braking, etc., were already positively verified in the previous season, while patient was using prosthesis of the same design, but purely mechanical (as mentioned in Section 2.2). As such, turning and braking was not validated here, especially due to technical reasons that patient was unable to bring his own bicycle. However, these functions were properly realized using a standard bicycle, with the front brake simply not used due to lack of grasping capabilities in the prosthesis end effector, and turning was perfectly possible using the C-shaped end effector.