**3.2. Virtual model**

Virtual human body models are used in many applications that allow human-machine Interaction. The virtual model created in this work aims to help the standardization of tests for the acquisition of the myoelectric signal. With this virtual model is possible, for the Subject, visualize the movement to be performed during the tests, so that all Subjects perform as best as possible, the same movements at the same time base and at the same time, leaving the system more user-friendly. For the development of the virtual model we used the software MakeHuman Alpha5 and Blender 1.0 Beta 2:54.

Initially, MakeHuman software was used to define the parameters of the humanoid (height, weight, sex) that is subsequently exported to the software Blender. This virtual model is a skeleton whose manipulative joints are used to define the positions that it should take (Tale & Balbinot, 2011). For the development of the animation it was necessary to set the start and end position and movement timing of each of the respective movement. The software then builds an animation by connecting the two points during a defined duration. Also was established a rest position which was adopted for all movements. Importantly, all movements start from the rest position, run and return to it. It should be noted that after the generation of virtual models, a video of the animations are created using a standard rate of 24 fps Avi format.

To display the animations, a routine in Labview was developed enabling the reading of Avi files and reproduction of videos representing the virtual model through a window of Windows Media Player. This window opens in the auxiliary display (LCD screen in Figure 4) being viewed only by the user of the system. The operator sees only the Labview programming window on the laptop screen, where it is shown that the signal is being acquired during the tests.

The set of movements generated through the virtual model was divided into two groups: simple and complex movements (sequence of simple movements). There are seven simple movements represented in Figure 5, which are: wrist flexion; hand contraction, wrist extension, forearm flexion, forearm rotation, hand adduction and hand abduction. For the simple movements were adopted the following time sequence with a total duration of each animation of 8.3 s:

• Initial interval: 0,4 s in which the animation will be on rest position;

• forward movement: duration of 2,9 s;

Computational Intelligence in Electromyography Analysis – 346 A Perspective on Current Applications and Future Challenges

order high-pass filters with cutoff frequency at 20Hz.

per channel) with an acquisition rate of 1 kHz per channel.

used the software MakeHuman Alpha5 and Blender 1.0 Beta 2:54.

**3.2. Virtual model** 

24 fps Avi format.

acquired during the tests.

animation of 8.3 s:

The frequency of the muscular signals captured by the surface electrodes has a range varying from 20 to 500 Hz. Due to this fact, the EMG designed consist of two cascaded second order low-pass filters with a cutoff frequency at 1000 Hz, and two cascaded second

To perform the data acquisition was chosen the National Instruments acquisition board NI USB 6008. This board features eight analog input channels with 10 bit resolution and sampling rate of 10 kS/s. In this study we used the eight analog input channels (one entry

Virtual human body models are used in many applications that allow human-machine Interaction. The virtual model created in this work aims to help the standardization of tests for the acquisition of the myoelectric signal. With this virtual model is possible, for the Subject, visualize the movement to be performed during the tests, so that all Subjects perform as best as possible, the same movements at the same time base and at the same time, leaving the system more user-friendly. For the development of the virtual model we

Initially, MakeHuman software was used to define the parameters of the humanoid (height, weight, sex) that is subsequently exported to the software Blender. This virtual model is a skeleton whose manipulative joints are used to define the positions that it should take (Tale & Balbinot, 2011). For the development of the animation it was necessary to set the start and end position and movement timing of each of the respective movement. The software then builds an animation by connecting the two points during a defined duration. Also was established a rest position which was adopted for all movements. Importantly, all movements start from the rest position, run and return to it. It should be noted that after the generation of virtual models, a video of the animations are created using a standard rate of

To display the animations, a routine in Labview was developed enabling the reading of Avi files and reproduction of videos representing the virtual model through a window of Windows Media Player. This window opens in the auxiliary display (LCD screen in Figure 4) being viewed only by the user of the system. The operator sees only the Labview programming window on the laptop screen, where it is shown that the signal is being

The set of movements generated through the virtual model was divided into two groups: simple and complex movements (sequence of simple movements). There are seven simple movements represented in Figure 5, which are: wrist flexion; hand contraction, wrist extension, forearm flexion, forearm rotation, hand adduction and hand abduction. For the simple movements were adopted the following time sequence with a total duration of each

• Initial interval: 0,4 s in which the animation will be on rest position;


**Figure 5.** Pictures representing the simple movements created by the virtual model: (a) resting position, (b) wrist extension, (c) wrist adduction, (d) wrist flexion (e) wrist abduction, (f) forearm flexion, (g) hand contraction and (h) forearm rotation.

In the Figure 6 is shown a static representation of the simple movements presented in video format.

The movements that are called complex are characterized by a combination of determined basic movements defined above. For this study, five complex movements were selected as shown in Figure 7, that are: hand contraction with forearm rotation, forearm rotation with forearm flexion; forearm rotation with forearm flexion and wrist flexion, hand contraction with forearm flexion and wrist extension and flexion.

For the animations of the complex movements, the same parameters of the simple movement animations were been used, but with total duration of 17 second for each complex movement.
