Using electroactive polymers to simulate the sense of light touch and vibration in a virtual reality environment

Virtual reality simulators seek to immerse users in realistic interactive environments. However, at present, while several provide kinesthetic feedback, most lack tactile feedback. Current means of tactile feedback do not generate enough force to the digits, deliver a non-intuitive sense of feedback and are too large or heavy to be used in hand-worn configurations. The tactile feedback system developed herein uses electroactive polymers to create light touch and vibratory sensation to the fingertips, and DC motors to constrict the distal digit. In essence, when current is passed through the electroactive polymer in the shape of a cantilever (7 mm long by 19 mm wide), it bends on its long axis, providing a forces of 25 mN. Vibratory feedback is created by varying input voltage with a sinusoidal waveform. To generate fingertip constriction, two DC motors cinch a wire attached to a rubber thimble. These hardware components are controlled by a computer running X3D software, an ISO standard for representing 3D graphics, which affords a virtual environment for the tracking of one´s hand. Upon contact with a virtual object, the actuators generate prescribed forces or vibrations. With this setup, a series of human-subjects experiments will be conducted whereby the task is to contact and differentiate virtual spheres of differing stiffness. Experiment 1 will test the electroactive polymers to determine the threshold for recognizing light touch, Experiment 2 will test vibrational discrimination, and Experiment 3 will test the ability of the user to differentiate constriction forces.