IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING (TBME-00067-2008.R1) 1 Nonlinear Modelling and Control of Human Heart Rate Response During Exercise With Various Work Load Intensities

Abstract—The first objective of this paper is to introduce a nonlinear system to model the heart rate (HR) response during and after treadmill walking exercise. The model is a feedback interconnected system which has components to describe the central and peripheral local responses to exercise, and their interactions. The parameters of the model were experimentally identified from subjects walking on treadmill at different speeds. The stability of the obtained nonlinear model was mathematically proven. The modelling results demonstrate that the proposed model can be useful in examining the cardiovascular response to exercise. Based on the nonlinear model, the second objective is to present a computer-controlled treadmill system for the regulation of HR during treadmill exercise. The proposed nonlinear con-troller consists of a feedforward and a feedback components. The designed control system was experimentally verified and the results demonstrated that the proposed computer-controlled treadmill system regulated the HR of the experimental subjects according to two different exercising HR profiles, indicating that it can play an important role in the design of exercise protocols for individuals. Index Terms—Cardiovascular system, exercise, H-infinity con-trol, linear-quadratic control, modeling, nonlinear systems, pa