Prototype of a haptic display for the evaluation of sensible haptic feedback in remote palpation

Abstract

Robot-assisted minimally invasive surgery generally forbids an important diagnostic tool in medicine: palpation. There are various approaches to re-establish 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. The pins have a stroke of 10mm with a maximum counterforce of 7N altogether. An additional force of 0.7N per pin can be applied with the motors. This technique allows for simultaneous stimulation of kinesthetic as well as tactile perception. Prior to development and construction, measurements with a haptic phantom (a silicone body with wooden balls included) were carried out in order to determine the parameters for the device. The measurements with the functional prototype show good reproducibility. Generally, the device works as intended and, where it does not, we could identify the sources of errors. The optimizations will flow into the construction of the complete setup. With the seven-pin setup we aim to reproduce the force profiles found in the phantom measurements and further examine the sensible simulation of tumorous soft tissue.