Cable-Driven Linear Haptic Display for Medical Interventions

Abstract

The technological state-of-the-art in numerous medical procedures involves high-end actively actuated equipment, leading the surgeon to only telecontrol the device, which is actually in contact with the patient, instead of guiding it directly by hand. Well-known examples are robot-assisted surgical interventions, where the user telecontrols the instrument via an input console, or procedures, which need to be performed using x-ray imaging, such as needle placement during biopsies or for drug injection [1]. Thus, potentially leading to improved accuracy, a lack of haptic sensation aggravates the process of perceiving important information for the surgeon, such as the mechanical characteristics of tissue boundary layers during needle insertion. In most disciplines, the forces during tool-tissue interaction are rather small and only slight changes of those interaction forces contain valuable information. This could be a threshold force from which a material will start to rip, or the force difference when a needle tip enters the next layer of tissue. To render these mechanical characteristics to the user, a dynamic haptic display with high mechanical bandwidth is required. These needs are perfectly met by haptic displays based on cable-driven parallel kinematics due to high stiffness and low inertia. Cable-driven haptic displays have been explored for various applications, such as for virtual reality or as a locomotion interface [2, 3], however, no research about application in medical telemanipulation was found. In this work, the capabilities and characteristics of a cable-driven haptic display for telemanipulation in the medical field have been investigated. As an exemplary application, the needle insertion process was chosen since there is only one degree of freedom (DOF) and very small changes in the tool-tissue interaction force. Cable- driven parallel kinematics have the advantage that they can be easily reconfigured and expanded to include additional DOF. In this paper, the mechanical setup and the dynamic characteristics of a cable-driven linear haptic display, in the following referred to as the haptic display, are presented.