Encountered-type haptic interface for virtual interaction with real objects based on implicit surface haptic rendering for remote palpation

The shortage of physicians afflicting developed countries encourages engineers and doctors to collaborate towards the development of telemedicine. In particular, robotic systems have the potential for helping doctors making examination. A very common examination that can be the goal of a robotic system is palpation. Most of the robotics systems that have been developed for palpation present interesting features such as integrating augmented reality environments or allowing for hand free interaction. In this paper we present a novel palpation system that allows us to perform virtual palpation of real objects by means of a haptic and an augmented reality feedback. This system features an encountered-type haptic interface in which the haptic feedback is calculated by a collision detection algorithm that is based on online recording of the surface to be touched. The system allows the users to remove their hand from the haptic interface end-effector that follows the user's hand thanks to the tracking performed by a Leap Motion. We show that the system provides a natural interaction during the contact-non contact switch, a suitable force during indentation, and it allows to discriminate objects within the body through the haptic channel.