Although a human can move his or her fingertip with six degrees of freedom (three for position and three for orientation), displaying 6DOF haptic cues continues to escape the capabilities of body-grounded fingertip haptic displays. All six degrees of freedom have been displayed in smaller subsets, so the limiting factor seems to be the additional volume, weight, and complexity of combining all six degrees of freedom in one device.
Meanwhile, robotics research in non-haptics areas has shown the potential of parallel continuum manipulators (PCMs) to be strong and compact. PCMs have six flexible wires that run from a stationary base platform to a free-moving distal platform, allowing the position and orientation of the distal platform to be controlled by adjusting the six wire lengths independently. This project aims to design and evaluate a wearable haptic device that is capable of delivering 6DOF tactile cues to a user’s fingertip by leveraging the compact and lightweight nature of PCMs.
After refining the design of a parallel continuum manipulator specifically for fingertip haptic applications [ ], we designed and constructed the motorized prototype seen in the figure above [ ]. A preliminary user study using a feed-forward position control scheme has shown that users can discern contact location quite well throughout the workspace of the device and that they discern shear cues moderately well depending on the contact location. This approach thus seems to have potential for delivering rich haptic cues to the fingertip of a user for interactions in augmented reality (AR) and virtual reality (VR).
Looking forward, we hope to use the created device to deliver better haptic cues by compensating for the precise shape and position of a user's fingertip, to explore the addition of force or position feedback via the contact surface, and to evaluate further the perception of high-dimensional haptic cues at the fingertip.