Fingertip digitizer: A real-time, fingertip-mounted haptic sensing system for active, dynamic, and viscoelastic touch

The capability of human beings to perform skilled tasks often depends on their ability to touch, grasp, and manipulate tools and control objects. An example where this is especially true is in the 3D digitizing industry, where a stiff probe has to make contact with the object under study. However, this tool-based interface has a major drawback---the outcome excludes the benefits of the unique feeling that comes from the direct finger contact on an object.; This dissertation introduces a new approach to finger touch interface. Based on the sensing methodology for dynamic human touch, called Active Touch paradigm, a sensory-enhanced virtual environment is proposed where both man and machine perfectly share the haptic stimuli. With this interface, overall work performance can be enhanced by the machine's digital power and the human's instinctive exploratory capability. In the present work, this concept is implemented through the invention and validation of a new dynamic fingertip digitizing device called the Fingertip Digitizer . The unique approach presented here adds a new perspective to the science of conventional passive human touch by adding active and dynamic aspects to it.; The specific aims of the present work are as follows: (1) develop a fingertipmounted hardware capable of tactile digitizing, (2) investigate dynamic features of fingertip characteristics in tactual tasks, and (3) develop touch-based applications of multimodal sensory feedback using the new Fingertip Digitizer.; All of the above aims were successfully completed. First, a fingertip-mounted digitizer, capable of capturing both static and dynamic phenomena at the finger tip, was developed. Second, the fingertip behavior during the dynamic tactual activities was investigated with the consideration of the fingertip's dynamic and viscoelastic behavior during active touch. Finally, three applications of the Fingertip Digitizer were developed: (1) Touch Painter & Touch Canvas: a 2D touch interface for intuitive drawing, (2) Tactile Tracer: a 3D touch interface for object digitizing, and (3) Touch Model Verifier: a verification methodology for comparing the haptic stimuli from the real physical objects and its corresponding virtual object through a haptic device.