Fourier modeling of porcine heartbeat and respiration in vivo for synchronization of HeartLander robot locomotion.

HeartLander is a small mobile robot which adheres to and navigates over the surface of the heart to provide therapies in a minimally invasive manner. HeartLander's ability to efficiently operate in this dynamic environment is greatly affected by physiological motion, namely the cardiac and respiration cycles. Synchronization of robot motion with minimal intrapericardial pressure results in safer and more efficient travel. The work presented models the physiological components of motion using Fourier series and estimates their parameters using an Extended Kalman Filter. Using the Fourier series parameters, estimates of physiological phase values are calculated to be used for step synchronization. The proposed methods are demonstrated on data from a HeartLander animal study for four locations on the heart. Mean respiration phase estimates are shown to be within 5% of the true respiration phases, while mean cardiac phase estimates are shown to have a minimum error of 11%.