Event Location: NSH 1305
Bio: Hong Z. Tan is an associate professor of electrical and computer engineering with courtesy appointments in mechanical engineering and psychological sciences at Purdue University. Her research of haptic human-machine interfaces focuses on haptic perception and its implications for engineering applications. She received her Bachelor’s degree in Biomedical Engineering from Shanghai Jiao Tong University, P.R. China. She earned her Master and Doctorate degrees, both in Electrical Engineering and Computer Science, from the Massachusetts Institute of Technology (MIT). She was a Research Scientist at the MIT Media Laboratory before joining the faculty at Purdue’s School of Electrical and Computer Engineering in 1998. She has held a McDonnell Visiting Fellowship at Oxford University, and a Visiting Associate Professorship in the Department of Computer Science at Stanford University. She was a recipient of the US National Science Foundation’s Early Faculty Development (CAREER) Award from 2000 to 2004. In addition to serving on numerous program committees, she was a co-organizer (with Blake Hannaford) of the International Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems from 2003 to 2005. She was the founding chair of the IEEE Technical Committee on Haptics, a home for the international interdisciplinary haptics research community, from 2006 to 2008. She is currently an associate editor of Presence: Teleoperators & Virtual Environments, ACM Transactions on Applied Perception and IEEE Transactions on Haptics.

Abstract: In my laboratory at Purdue University, we conduct research on haptic human-machine interfaces with an emphasis on applying knowledge of haptic perception to solving engineering problems. I will start the talk with a brief overview of ongoing research in three directions: basic study of human perception of mechanical properties, haptic interface development and evaluation, and multisensory perception and crossmodal interaction. I will then discuss a recent study motivated by the need to compress haptic signals for transmission over a band-limited network, with possible applications in a teleoperated robotic system. I will describe three experiments where the detectability and discriminability of virtual haptic gratings are analyzed in the frequency domain. In the first two experiments, detection and discrimination thresholds for virtual haptic gratings were estimated, respectively, using a force-feedback device that simulated sinusoidal and square-wave texture gratings. The detection threshold results indicated that at higher spatial frequencies, the detectability of square-wave gratings could be predicted quantitatively from the detection thresholds of their corresponding fundamental components. Results from the second experiment confirmed that at higher spatial frequencies, the square-wave gratings were initially indistinguishable from the corresponding fundamental components until the third harmonics were detectable. At the lower spatial frequencies, the third harmonic components of square-wave gratings had lower detection thresholds than the corresponding fundamental components. Therefore, the square-wave gratings were detectable as soon as the third harmonic components were detectable. A third experiment was conducted where gratings consisting of two superimposed sinusoidal components were compared. It was found that people were insensitive to the relative phase between the two components. Our results provide quantitative guidelines for engineering applications where complex haptic signals are transmitted at high update rates over a network with limited bandwidth.