Rate-hardness: a new performance metric for haptic interfaces

• Published in: IEEE transactions on robotics and automation Vol. 16; no. 4; pp. 357 - 371
• Main Authors: Lawrence, D.A., Pao, L.Y., Dougherty, A.M., Salada, M.A., Pavlou, Y.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.08.2000; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Actuators; Degrees of freedom; Eyes & eyesight; Force measurement; Force sensors; Haptic interfaces; Hardness; Human; Humans; Mathematical analysis; Perception; Physics; Psychology; Rendering; Rendering (computer graphics); Sensory perception; Stability; Testing; User interfaces; Virtual reality; Walls
• ISSN: 1042-296X; 2374-958X
• DOI: 10.1109/70.864228

Rate-hardness is introduced as a quality metric for hard virtual surfaces, and linked to human perception of hardness via a psychophysical study. A 3 degree-of-freedom haptic interface is used to present pairs of virtual walls to users for side-by-side comparison, 19 subjects are tested in a series of three blocks of trials, where different virtual walls are presented in randomly ordered pairs. Results strongly support the use of rate-hardness, as opposed to mechanical stiffness, as the more relevant metric for haptic interface performance in rendering hard virtual surfaces. It is also shown that common techniques of enhancing stability of the rendered surfaces tend to actually enhance performance as measured by rate-hardness.