Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
MYOELECTRIC HAND PROSTHESIS CONTROL CONSIDERING INTERPHALANGEAL STIFFNESS
Submission Author:
Jean Mendes Nascimento , SP
Co-Authors:
Jean Mendes Nascimento, Paulo Marcos AGUIAR, Leonardo Marquez Pedro, Tarcisio Leão
Presenter: Jean Mendes Nascimento
doi://10.26678/ABCM.COBEM2021.COB2021-1282
Abstract
Muscles usually work in pairs or groups, they function both as agonist and antagonist. When one muscle flexes the other one extends in order to allow and stabilize the movement, what also depends on the attachment’s angles, bonding lengths, moments and strength directions. A variety of muscles and tendons are bounded together by more than one joint. In the fingers, some flexor and extensor tendons take place to four joints. During the movement from many ligaments, undesired torque might be generated, and they must be balanced by muscular strength. Most daily human hand movement are not precise, then the mechanical prosthesis project should be closer to a hand then to a tool. Once the mechanics of the prosthesis naturally goes to a proper movement, the control system became simpler. In this paper is presented a simpler controlling device outlined in a more intuitive way, carrying out far less restrictions in regard of positioning and prosthetic orientation. Such a system was obtained by adding passive stiffness on the prosthetic hand phalanx. Hereby all myoelectric sensors signals are adjusted to the stump, using a tensioned bracelet, which offsets the loss of contact, contributing to a global grabbing operation efficiency. The prosthetic hand stand point and orientation were carefully designed for the grabbing process success. The prototype tested in the laboratory was effective when the grab process is the focus not the manipulation.
Keywords
upper limb prosthesis, stiffness control, hand rehabilitation, myoelectric signals
