Toward hybrid force/position control for the Cerberus epicardial robot.

Gene therapies have emerged as a promising treatment for congestive heart failure, yet they lack a method for minimally invasive, uniform delivery. To address this need we developed Cerberus, a minimally invasive parallel wire robot for cardiac interventions. Prior work on Cerberus was limited to controlling the device using only position feedback. In order to ensure safety for both the patient and the device, as well as to improve the performance of the device, this paper presents work on enhancing the existing system with force feedback capabilities. By modeling the statics of the system and developing a tension distribution optimization technique, existing position control schemes were modified to a hybrid force/position controller. Experimental results show that using a hybrid force-position control scheme as opposed to position decreases positioning error by 38%.