Active filtering of physiological motion in robotized surgery using predictive control

TLDR

Physiological motion from respiration and heartbeat causes complex, periodic disturbances in robotized surgery, with cardiac motion being particularly complex due to two nonharmonic components. The study proposes a predictive‑control strategy to actively filter organ motions caused by respiration and heartbeat during robotized surgery. The authors develop two generalized predictive controller (GPC) schemes—one exploiting the periodicity of respiratory motion and another using an adaptive disturbance predictor for cardiac motion—each with a cost function that separates reference tracking from periodic disturbance rejection, and validate them on a laboratory testbed and in vivo pig experiments. Experimental results confirm that both predictive‑control methods effectively compensate complex physiological motion.

Abstract

This work presents a predictive-control approach to active mechanical filtering of complex, periodic motions of organs induced by respiration or heart beating in robotized surgery. Two different predictive-control schemes are proposed for the compensation of respiratory motions or cardiac motions. For respiratory motions, the periodic property of the disturbance has been included into the input-output model of the controlled system so as to have the robotic system learn and anticipate perturbation motions. A new cost function is proposed for the unconstrained generalized predictive controller (GPC), where reference tracking is decoupled from the rejection of predictable periodic motions. Cardiac motions are more complex, since they are the combination of two periodic nonharmonic components. An adaptive disturbance predictor is proposed which outputs future predicted disturbance values. These predicted values are used to anticipate the disturbance by using the predictive feature of a regular GPC. Experimental results are presented on a laboratory testbed and in vivo on pigs. They demonstrate the effectiveness of the two proposed methods to compensate complex physiological motion.