## 3 Materials and Methods  
### Dataset, Acquisition Device, and Implementation Details  
The dataset selected for this project was the publicly available NinaPro Database 5 (DB5) [25]. The NinaPro series consists of EMG datasets acquired using various devices, and the NinaPro DB5 utilizes the Myo armband as its acquisition device [26]. It includes data collected from 10 healthy subjects using two Thalmic Myo armbands. The subjects wore the upper armband closer to the elbow, with the first electrode positioned on the radio-humeral joint. The lower Myo armband was placed just below the upper one, closer to the hand, and tilted by 22.5 degrees to cover the gaps left by the electrodes of the upper armband. Additionally, the subjects wore a glove (CyberGlove II dataglove) equipped with 22 sensors to record hand kinematics. The Myo armband acquisition system (Figure 1 left) from Thalmic Labs is a wearable band placed right below the elbow that contains 8 electrodes for sEMG acquisition, at 200 Hz and 8-bit resolution, and a nine-axis IMU composed of a three-axis accelerometer, gyroscope, and magnetometer [26]. It is also equipped with a tactile sensor to transmit feedback to the user with short, medium, and long vibrations. The device includes a Freescale Kinetish ARM Cortex M4 120 MHz, MK22 FN1M MCU, and BLE (Bluetooth low energy) NRF51822 chip to communicate with other devices. The device is powered by 2 \(\times\) lithium batteries 3.7 V--260 mAh. The Myo armband transmits data via Low-Energy Bluetooth, which is a great advantage for a robotic prosthesis as it consumes less power and allows the system to last longer before needing to be charged. The typical placement and configuration for acquisition can be seen in Figure 1 (right). The complete dataset contains sEMG signals from both Myo armbands, accelerometer data from the upper Myo, and finger joint angles from the glove. However, for the purposes of this project, only the sEMG data from the upper Myo was used. The data acquisition process was divided into two phases: a training phase and the actual recording of three different exercises. During both phases, the subjects were seated comfortably in a chair, resting their dominant arm on a desk. A laptop was placed in front of each subject to provide visual instructions and to record the data. In the training phase, each subject was instructed to replicate the movements displayed on the screen. These movements were chosen randomly to allow the subjects to familiarize themselves with the task. In the recording phase, each subject was instructed to repeat three different exercises. Each exercise was made of different movements, and every movement was repeated 6 times lasting 5 s each, with a 3 s rest between every movement to avoid muscular fatigue. The dataset contains 52 different movements from the hand taxonomy and robotics literature. The 10 subjects that participated in these experiments were all healthy but had substantial differences in gender, height, and weight (Table 1). After the sEMG signal was acquired, the raw data underwent pre-processing. The Myo armbands are equipped with a Notch Filter that removes powerline interference (set at 50 Hz). However, there was a slight desynchronization between the visual input from the computer and the actual recorded sEMG signals due to the delay caused by human reaction \begin{table}
\begin{tabular}{c c} \hline \hline  & **Ninapro DB5 Thalmic Myo (Double and Single)** \\ \hline Available subjects & 10 \\ Considered subjects & 10 \\ Males & 8 \\ Females & 2 \\ Right-handed & 10 \\ Left-handed & 0 \\ Avg. age (years) & 28 \(\pm\) 3.97 \\ Avg. height (cm) & 172.2 \(\pm\) 9.88 \\ Avg. Weight (kg) & 68.6 \(\pm\) 9.1 \\ Avg. BMI (kg/m\({}^{2}\)) & 23.17 \(\pm\) 2.66 \\ Exercise & NinaPro DB5 Exercises B (Posture 7) and C \\  & (Postures 1, 4, 8, 9, 14, 15, 18) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Information about the subjects of the experiments and the exercises from NinaPro DB5.