The haptic desk – towards a more natural interface to train surgical palpation tasks

During surgical palpation, fingers move freely over large surfaces as they are exposed to variations in texture, friction, slip, stiffness, surface deformation and so on. The vast majority of nowadays’ virtual reality trainers are operated through stylus-based haptic display systems. The fidelity of these systems, especially with respect to the rendering of palpation tasks, is limited as these devices literally force the operator to explore the virtual environment through mediation of an instrument. In this work we present the haptic desk a novel haptic display system that was designed especially to allow free and relative motion between the operator and the environment. This property is considered key to come to a more natural palpation interaction. Figure 1 provides an overview of a general haptic desk. The system is based on encountering technology. This means that it includes a haptic display that is programmed to only engage with the operator when the latter reaches/touches the virtual organ. When not contacting the organ there is no contact with the haptic device, hence free motion can be rendered perfectly. With such layout it is also possible to realize relative motion (slip) between finger and organ. To follow and anticipate the operator’s motion the pose of the finger must be tracked. In this work we discuss the haptic desk that was built at our department and describe some user experiments that were conducted confirming the feasibility and performance of palpation through the novel display system.