Development of a Robotic System to Enable Beating-heart Surgery

Performing a surgical procedure on a beating heart is nearly impossible as the surgeon must simultaneously follow the heart’s motion and perform a surgical task. Assume the position of a target point for operation on the heart’s (interior or exterior) surface is captured in ultrasound images. If a robotic system could move a surgical tool in synchrony with this target point while the heart beats, the surgeon could then perform the surgical procedure as if the beating heart were stationary. This paper discusses the electromechanical and control design issues in such a system. An experimental testbed is described that consists of an optical motion tracker to simulate the function of an ultrasound imager, a mechanical heart motion simulator, and a voice-coil actuator for holding the surgical tool. An approach based on a Smith predictor is proposed to compensate for the delay introduced by the required image acquisition and processing. Another issue is the slowly (20 Hz) sampled data from the ultrasound images, which is upsampled to 100 Hz using either a zero-order-hold or a cubic interpolator. Experimental results are reported with the goal of having the surgical tool follow the combined motion of the surgeon and the beating heart.