STUDY OF AUTONOMOUS DISTRIBUTED CONTROL SYSTEM HAVING NATURAL ORGANS?? FEATURE FOR HIGHER INTELLIGENT CONTROL OF ULTRA LIGHTWEIGHT VAD

Abstract

Basic study for realization of adaptation, evolution, and self-diagnosis on an artificial heart has been carried out by an autonomous distributed control system for an ultra-lightweight pulsatile VAD (volume of 285 ml and weight of 360 g). The autonomous distributed control system was build by 4 layers (input layer, measurement layer, control layer, output layer) and an object manager, which was realized on a l chip microcomputer (Hitachi, SH7044, Japan). The input and output layer are composed of ND, PIO, SIO for interface with the VAD. The measurement layer consists of 4 autonomous objects: current measurement, velocity measurement, position measurement, and timer. The control layer consists of 3 autonomous objects: position control, velocity control, and current control. The position and velocity control object are constructed by fuzzy inference algorism in order to build doctors' and engineers' knowledge into the VAD control. The object manager paces events on each object in order to maintain time series processes. The control system can he adapted to an axial flow VAD by exchanging the position measurement and position control object into a flow estimation and flow control object. In vitro experiment showed that The VAD was driven stably enough to maintain cardiac function by cooperation of independently operated each object like cells in the control system. In conclusion, the above results shows that the autonomous distributed control system promises suitability as a new superior artificial control system.