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Advisor(s)
Abstract(s)
O objetivo do projeto era mover um servomotor com certo ângulo usando o sen-
sor Bitalino EMG. Para esse fim, foi necessário desenvolver compatibilidade entre o
sensor Bitalino EMG e a placa Arduino UNO. Além disso, o sinal bruto obtido a partir do
sensor teve que ser transformado em sua forma apropriada para habilitar o controlo do
servomotor. Vários conceitos e abordagens levaram a uma solução específica que con-
tribuiu para o movimento do servomotor enquanto a contração muscular era detectada
e ajustando o servomotor na posição inicial enquanto o músculo estava em repouso.
Neste caso, com o uso de três eletrodos secos, investigou-se o músculo extensor digito-
rum communis, cuja principal função é movimentar as falanges e o pulso. À medida que
a eletromiografia permitiu as traduções de sinais bioelétricos em valores numéricos,
a forma bruta do sinal foi deslocada e a função função módulo foi aplicada para obter
apenas valores positivos. Posteriormente, o algoritmo foi usado para transformar o si-
nal em forma envolvida. Tendo em conta os valores do sinal envolvido, o servomotor
foi movido de acordo com a magnitude do limiar estimado. O valor limite corresponde
à borda do sinal acima do qual a contração ocorreu, enquanto abaixo desse valor não
foi denotada contração. O projeto serve de base para possíveis desenvolvimentos em
diferentes áreas,, por exemplo, na criação de braço robótico ou prótese móvel para
pessoas com deficiência. Assim, investigação mais ampla deve ser realizada a fim de
proporcionar uma melhor fluência e menor tempo de reação entre a contração e os
movimentos do servomotor.
The aim of the project was to move a servomotor with certain angle using Bitalino EMG sensor. For such purpose, there was required compatibility between Bitalino EMG sensor and Arduino UNO board. Furthermore, the raw signal obtained from the sensor had to be transformed to its appropriate form to enable servomotor control. Several concepts and approaches led us to one specific solution which contributed to moving the servomotor while muscle contraction is detected and setting the servomotor at starting position while the muscle is at rest. In this case, with using three dry electrodes, there was investigated the extensor digitorum communis muscle which main function is to extend the phalanges and the wrist. As the electromyography enabled the trans- lations of bioelectrical signals into numerical values, the raw form of the signal was shifted and absolute value function was applied in order to obtain only positive values. After that, the special algorithm was used to transform the signal to its enveloped form. Taking into account the values of enveloped signal, the servomotor was moved accord- ing to estimated threshold magnitude. Threshold value corresponds to the edge of the signal above which the contraction occurred, while below this value no contraction was denoted. The project can be treated as the base for further development for example in creation of robotic arm or moving prosthesis for disabled people. Thus, the wider inves- tigation should be undertaken in order to provide better fluency and shorter reacting time between contraction and servomotor movements.
The aim of the project was to move a servomotor with certain angle using Bitalino EMG sensor. For such purpose, there was required compatibility between Bitalino EMG sensor and Arduino UNO board. Furthermore, the raw signal obtained from the sensor had to be transformed to its appropriate form to enable servomotor control. Several concepts and approaches led us to one specific solution which contributed to moving the servomotor while muscle contraction is detected and setting the servomotor at starting position while the muscle is at rest. In this case, with using three dry electrodes, there was investigated the extensor digitorum communis muscle which main function is to extend the phalanges and the wrist. As the electromyography enabled the trans- lations of bioelectrical signals into numerical values, the raw form of the signal was shifted and absolute value function was applied in order to obtain only positive values. After that, the special algorithm was used to transform the signal to its enveloped form. Taking into account the values of enveloped signal, the servomotor was moved accord- ing to estimated threshold magnitude. Threshold value corresponds to the edge of the signal above which the contraction occurred, while below this value no contraction was denoted. The project can be treated as the base for further development for example in creation of robotic arm or moving prosthesis for disabled people. Thus, the wider inves- tigation should be undertaken in order to provide better fluency and shorter reacting time between contraction and servomotor movements.
Description
Keywords
Enveloped signal Arduino Electromyography Servomotor
Citation
Krzyżanowska, Katarzyna; Duczmalewska, Aneta; Rocha, João (2017). Control dos movimentos do servomotor usando o sinal EMG = Control of servomotor movements using EMG signal. In V Encontro de Jovens Investigadores do Instituto Politécnico de Bragança. Bragança: Instituto Politécnico. ISBN 978-972-745-235-4
Publisher
Instituto Politécnico de Bragança