Innovative forearm prosthesis with simultaneous control of three functions of an artificial brush

Authors:

Burov Gennady Nikolayevich, PhD in Technical sciences, Head of scientific direction, Federal State Budgetary Institution “Federal Scientific Center of Rehabilitation of the Disabled named after G.A. Albrecht”, Ministry of Labor and Social Protection of the Russian Federation, 50 Bestuzhevskaya Street, 195067 Saint Petersburg, Russian Federation, zxzy@yandex.ru

Bolshakov Vladimir Alexandrovich, Head of design department, Federal State Budgetary Institution “Federal Scientific Center of Rehabilitation of the Disabled named after G.A. Albrecht”, Ministry of Labor and Social Protection of the Russian Federation, 50 Bestuzhevskaya Street, 195067 Saint Petersburg, Russian Federation, pko09_903@mail.ru

Drobakha Alena Sergeevna, junior research associate, Federal State Budgetary Institution “Federal Scientific Center of Rehabilitation of the Disabled named after G.A. Albrecht”, Ministry of Labor and Social Protection of the Russian Federation, 50 Bestuzhevskaya Street, 195067 Saint Petersburg, Russian Federation, drobaha-alena@mail.ru

Annotation:

Introduction. The main feature that determines the principle of operation of any controlled device (prosthesis) is the control method. The main methods of prosthetic arm control include the following: traction control meth- od, mechanical traction control, inertial control, myotonic control, bioelectric control, and contact control method.
Combining methods is used depending on the capabilities and needs of the disabled person during prosthetics.
However, in multifunctional devices, control still remains alternate due to the limited number of control signal sources. The number of such sources is less, the higher the level of amputation. In all cases of manipulating objects, a disabled person has to use the mobility of the residual segments of the arm and shoulder girdle.

Aim. The purpose of the study is to improve the rehabilitation process for disabled people with amputation de- fects of the forearm, which consists in developing a proposal for the creation of a forearm prosthesis with simultane- ous control of an artificial hand with several functions of mobility, namely, the gripping function (opening-closing), rotation and bending.

Materials and methods. The implementation of the simultaneous control of two or three degrees of mobility of the prosthesis of the forearm requires a comprehensive solution in terms of receiving the master control signals, their conversion and interaction with actuators.
In the course of the study, the possibility of simultaneous, without additional switching, control of the following mobility functions was revealed – opening-closing of the grip, rotation, and bending-extension of the artificial brush.
Considering each of these actions in turn, it is necessary to determine the design features of the sensitive ele- ments and the mechanism of their influence on the system of executive prosthesis drives. Due to the fact that the drives are controlled simultaneously, it is very important to establish and evaluate the mutual influence of the con- trol signals on each other.
Results. The research carried out in this direction and the subsequent development of the gripping, rotation and bending nodes of the artificial hand made it possible to substantiate the theoretical and practical possibility of creat- ing a forearm prosthesis with simultaneous control of the three functions of the artificial hand.

Discussion. Having examined the design features of well-known artificial brushes, including new developments, we can conclude: along with the rather attractive functionality of these devices, they do not solve the problem of active orientation of the brush in the space of the working area. There is no bending and rotation of the brush in an active form, close to natural.

Conclusion. The study allowed us to formulate the principles for constructing constructive versions of the fore- arm prosthesis, to develop a method for recording the angle of rotation of the shoulder when controlling the bending of the artificial hand, to select sensitive elements of the control systems for the degrees of mobility of the prosthesis of the forearm, and to develop options for the design of the master sensors.

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