Músculos artificiais baseados em polímeros eletroativos aplicados à robótica de reabilitação

• Autor(a) principal: Prado, Adilson Ribeiro
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/4060
• topic: 621.3; Engenharia Elétrica; Músculos; Polímeros; Braços; Robótica; Reabilitação

This research deals with the synthesis and activation of the polymer polypyrrole (PPy), which when stimulated electrically in special saline bath changes in volume. This characteristic is similar to that of human muscle. This electro-active polymer is also known as arti cial muscle. The purpose of this study is to investigate the potential of this polymer, for use as an actuator of upper limb prostheses. Speci cally, articulated junctions simulating human hand were studied. Polypyrrole was synthesized electrochemically. The conditions of synthesis were adjusted to obtain a product with desired characteristic. Afterwards, electric drive processes were investigated with the polymer immersed in saline solution, which is necessary to attain the volumetric variation. The drive used had constant potential and current density and, in all cases, gave an amplitude superior that considered as a minimum value for e cient movement of Distal Interfalange DIP (40◦). In addition to electrochemical techniques such as chronoamperometry and cyclical voltammetry digital, image processing by way of segmentation of digital images was used for the interpretation of the results for analysis of the actuator movements. A commercially available polymer called IPMC (Ionomeric Polymer-Metal Composites) was used as a reference to evaluate the comparative advantages and disadvantages of the polypyrrol polymer. It was found that this type of material has a great advantage in relation to polypyrrole because of its capacity to produce movements and its ability to work in dry state. However, it was observed that this material must be frequently hydrated to maintain e cient movement. The great advantages of the polypyrrole produced were the low cost of its synthesis, low energy consumption and the large amplitude of movement obtained, which support its appropriateness for this type of application. It must be emphasized that the actuator developed like the commercial product has the important characteristics of silent operation, a very important factor in a construction of prosthesis of the upper extremity. With objective to compare and to verify the advantages and disadvantages of the material produced here, another similar polymer was bought, called IPMC, which was studied and analyzed. It was veri ed that this type of material possess great advantage in relation to the PPy, due to its capacity of accomplishment of movements in saw dries, because not necessity of the immersion in liquid for drive. However, it was observed that it must frequently be hydrated, so that its movement is e cient. The great advantages observed in the polipirrol produced is the low cost of its synthesis, the low consumption of energy and the high values of gotten amplitude in its displacements. It must be salient that the developed actuator, as well as the acquired one, presents the important characteristic not to generate acoustic noises in its drives, which is a very important factor in the construction of upper limb prostheses, since this type of noise consists of an important factor of rejection on the part of the users of the currently commercialized technologies.