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Fingerpad Skin Deformation for Sensory Substitution of Force in Teleoperation and Virtual Reality
Abstract:
During real-world physical interaction, haptic information provides people with important information about environment properties and interaction forces. While world-grounded kinesthetic devices have traditionally been used to provide multi-degree-of-freedom haptic feedback to the users of teleoperation and virtual reality systems, another option is skin deformation feedback, where a device stimulates mechanoreceptors within the skin. Skin deformation can be used to convey force information similar to that provided by kinesthetic devices, but does not necessitate external grounding, meaning that it could potentially function in much larger workspaces. This thesis presents the development and evaluation of novel skin deformation devices for sensory substitution of force in teleoperation and virtual reality applications.
With a new lateral skin deformation device capable of deforming skin on the fingerpads during teleoperation of a robot manipulator, we showed that user stiffness discrimination was as good with skin deformation feedback as with kinesthetic force feedback. The usefulness of this device and feedback method were validated in a teleoperated palpation experiment, during which participants performed just as well as with kinesthetic feedback and better than with previously investigated sensory substitutes, without the risk of feedback-induced instability. Next, we designed and validated a new fingertip-wearable skin deformation device for use in virtual reality systems. Users were able to perform virtual palpation and surface friction discrimination with feedback from this device. By using two of these devices on the index finger and thumb, we showed that naive users were able to determine virtual object physical properties such as mass, stiffness, and friction with no prior experience or training. Finally, we integrated haptic rendering with pseudohaptic graphical scaling to extend the range of virtual mass rendering and determine how mass perception is affected by the haptic and visual channels when using skin deformation feedback.
These results show that skin deformation feedback is an effective substitute for kinesthetic force feedback in both teleoperation and virtual reality scenarios. With minimal training, users of systems with skin deformation feedback are able to perform nearly as well as with true force feedback, while avoiding many of the issues traditionally associated with kinesthetic feedback systems.
