autonomous distributed control system for totally implantable assist pump sisytem

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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 built by 4 layers (input layer, measurement layer, control layer, output layer) and an object manager, which was realized on a lchip microcomputer (Hitachi, SH7044, Japan). The control layer consists of 3 autonomous objects: position control, velocity control, and current control. The position and velocity control objects 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.In vitro experiments showed that The VAD has maximum pump outflow of 5.1 L/min against afterload of 100 mmHg under control of our autonomous control system.The self-diagnosis has been realized by a neural network based early diagnosis system using artificial heart sound. A long-term animal experiment showed that the early diagnosis system automatically and successfully had detected malfunction of pump 24 hours before pump stoppage.The above results show that our VAD system promises possibility as a new superior artificial heart system.