Scientific journal
European Journal of Natural History
ISSN 2073-4972

DESIGN OF MECHATRONICAL UNIT WITH CAM ACTUATOR FOR ARTIFICIAL HEART VENTRICLE

Morozov V.V., Chikurnikova A.S.
Last years in the world the tendency of increase in quantity of operations on implantation of the mechanical devices supporting heart activity as change of donor organ is connected with many insoluble biological and social problems is observed and cannot provide all needs. Today completely to satisfy need for donor hearts it is not possible, therefore the problem in creation of autonomous implanted systems of auxiliary blood circulation and artificial heart is extremely actual.

In the decision of this problem it is possible to allocate two basic directions: constant replacement of natural body with an artificial limb completely replacing pump function of heart and capable long years to support blood circulation that is total artificial heart; temporary replacement of function for the period of treatment of the heart before recovery of its functional ability. Methods of the temporary heart assistance and replacements of its delivery function by the mechanical devices relate to the last direction incorporated by concept « auxiliary blood circulation ».

By development of the mechatronical module of left ventricle assist device (LVAD) with executive mechanism of cam actuator type it is necessary to adhere to requirements of reliability of maintenance of a continuous flow in the system of blood circulation at given antipressure and a low trauma of blood, maintenance of stability of work at pulsing change of pressure and the charge on its input. It should guarantee full tightness of the working cavity of the pump in relation to the environment, have the minimal sizes and weight for implanted variants of application, a low level of pulsations and noise. Researches have shown, that this mechatronical module at the given characteristics is capable to satisfy the above described requirements.

As cam actuator was chosen triple mechanism with a target pusher. For replacement of a sliding friction with friction stagger and reduction of wear of a cam in the scheme of the mechanism the additional part - a roller is included. Mobility is local in this kinematical pair and does not change transfer functions of the mechanism. Given mechanism of the cam actuator is intended for transformation of linear motion of a cam to back and forth motion of the pusher. Thus in the executive mechanism of the given type, it is possible to realize transformation of movement under the complex law. One of the important advantages of the cam actuator is the opportunity of maintenance of the exact stops of the output. At the designing the given mechanism in structure of LVAD it is necessary to consider its heat-power characteristics, as at work of a drive a thermal emission is inevitable, but it does not reach so high values to lead to the heating of the body because motor works in a mode without reverse. This basic advantage of the offered design with a cam in comparison with earlier drive of the LVAD on the basis of roller-screw mechanism was developed in Vladimir State University.

Work is carried out at support of analytical program RusEducation «Development of the scientific potential of the high school (2006-2008)» (project RNP-2.1.2.3641) and ordered by Scientific Research Institute Of Transplantology And Artificial Organs under a scientific management of the professor Morozov V.V.

The article is admitted to the IV Scientific Conference "Modern Problems of Experimental and Clinical Medicine", Thailand, 2007, January 17-28; came to the editorial office on 12.11.06.