Some challenging feedback-control applications in biomedical systems

Natural biological control involves the normal functioning of the living organism (i.e. human body) to regulate its parameters such that the vital functions are kept within the normal operating range. When this natural control fails, the biological feedback (thus a closed loop system) is unstable and/or operates under non-optimal conditions of the vital capacity of the subject. In this context, ensuring surviving capacity of the subject implies to artificially control the vital functions presenting the functional failure. Nowadays technology enables development of artificial closed loop devices to correct and provide the normal functions of the organism, replacing thus the damaged/non-optimal parts or helping in recovering their natural properties (rehabilitation techniques). Two of the most en-vogue applications of artificial control will exemplify the importance and the posed challenges: - a neuroprothesis device to control paralyzed skeletal muscles; this enables rehabilitation of drop-foot or hand-grasp movements with paretic or paralyzed skeletal muscles by use of a self-adaptive (auto-tuning) control strategy; - and an artificial pancreas for diabetes type I patients; the blood glucose control in diabetic patients type I is made by use of an in-house developed model-based predictive control algorithm in which input (insulin rate) and output (glucose level) are constrained.