A haptic display for tactile and kinesthetic feedback in a CHAI 3D palpation training scenario

Robot-assisted minimally invasive surgery generally prevents the use of an important diagnostic tool in medicine: palpation. There are various approaches to reestablish the haptic feedback for the surgeon, including tactile displays and haptic input devices. We present a novel haptic display that features seven pins mounted on compression springs that can be pre-loaded with servo motors. Each pin has a stroke of 10 mm and a maximum counterforce of 1.1 N. An additional force of 0.7 N per pin can be applied with the motors. This technique allows for simultaneous stimulation of kinesthetic as well as tactile perception. The control of the haptic display has been implemented in the open-source haptics library CHAI 3D. We extended the framework with a multi interaction point tool to represent the hardware. This eventually lead to a palpation training program where bodies with multiple adjustable parameters encapsulated in a virtual soft tissue can be simulated. We evaluated this software in a user study with 15 participants in order to demonstrate the usability of the haptic display. With 90 % of successful hits, we are confident that sensible haptic feedback can be generated with the presented device. Furthermore, we are currently extending the scope of the haptic display to make use of a novel capacitive tactile proximity sensor in exploration scenarios.