A Haptic Modeling System

Haptics has been studied as a means of providing users with natural and immersive haptic sensations in various real, augmented, and virtual environments, but it is still relatively unfamiliar to the general public. One reason is the lack of abundant haptic content in areas familiar to the general public. Even though some modeling tools do exist for creating haptic content, the addition of haptic data to graphic models is still relatively primitive, time consuming, and unintuitive. In order to establish a comprehensive and efficient haptic modeling system, this chapter first defines the haptic modeling processes and its scopes. It then proposes a haptic modeling system that can, based on depth images and image data structure, create and edit haptic content easily and intuitively for virtual object. This system can also efficiently handle non-uniform haptic property per pixel, and can effectively represent diverse haptic properties (stiffness, friction, etc)

Structural and elastic properties of silver-palladium and copper-palladium superlattices.

I prepared Ag/Pd and Cu/Pd superlattices using both sputtering and molecular beam epitaxy. For the Ag/Pd (t(Ag):t(Pd) = 1:1) superlattices, I observed two distinctive behaviors in the structural coherence length ξ as a function of modulation wavelength Λ. Using Brillouin light scattering (BLS) I observed a 50% enhancement of the shear elastic constant c₅₅ and a 16% increase of c₁₁ with decreasing Λ. Annealing study showed that a high structural order of the films in the growth direction was strongly correlated to the increase of c₅₅. For the 3:1 and 1:3 Ag/Pd samples, I also observed a monotonic increase of the Rayleigh velocity υ(R) (or c₅₅) with decreasing Λ and similar behavior in the structural coherence length to the 1:1 samples. In conclusion, the recrystallization of the alloy and the formation of extended interfaces by intermixing at the Ag-Pd interfaces are responsible for a large enhancement of c₅₅. Using BLS for the Cu/Pd superlattices, I observed a 24% decrease of c₅₅ as Λ was decreased to ∼30-40 Å, followed by a rapid increase for smaller Λ. The observed homogeneous strain in the growth direction showed a strong relationship with c₅₅. The strain was localized at the interface and the Cu/Pd films were in compressive stress for Λ 40 Å. I observed no in-plane anisotropies in υ(R) as predicted from theory for single crystal films

Human perception of pneumatic tactile cues

The ability to combine tactile, on-the-skin, sensory cues with the kinesthetic ones that widely available force-feedback devices are able to produce is a desirable one, opening the door to the production of more realistic, compelling virtual environments. Pneumatic air-jet displays can be easily mounted on existing force-feedback devices and we believe have the potential to provide useful complimentary tactile information. However, there is little concrete psychophysical data relating to pneumatic displays - a fact that hinders their adoption. This paper addresses this challenge, and presents brief psychophysical studies examining localization rate, the two-point threshold and the stimulus intensity of cues produced by pneumatic air jets. Using insights gained from these studies, we also present a more concrete application-focused investigation where we evaluate the effect of combining tactile and force-feedback cues in a simple object manipulation task in a virtual environment. We show that task completion times are significantly improved with the addition of tactile information, validating our ideas and suggesting this topic warrants further attention.close2

Binder-free hybrid Li4Ti5O12 anode for high performance lithium-ion batteries

We have developed a new binder-free hybrid anode material for lithium-ion batteries, by directly coating spinel Li4Ti5O12 particles using in-situ polymerization of styrenesulfonate (SS) to form a core-shell structure. The resulting hybrid anode has significantly improved electrochemical performance, with higher reversible capacity, rate-capability, and capacity value compared with pure Li4Ti5O12. Of the initial discharge capacity of 239.2 mAh g(-1), 95.6% was retained after 100 cycles at 0.1 C-rate. The high cycle performance with increased discharge capacity is attributed to the coated poly (styrenesulfonate) (PSS) shell, which takes part in lithium ion storage and prevents the growth of a solid electrolyte interface (SEI) layer. The fast electron transfer in PSS also allows high rate-capability. Moreover, we clarify the contribution of carbon conductor in the range of 0.01 V-1.0V

Effect Of Thermal Annealing On Elastic Properties Of Ag/Pd Superlattice Films

We report a 50 % increase in the shear elastic constant c55 in Ag/Pd superlattice films upon thermally annealing as measured by Brillouin light scattering. X-ray diffraction studies show that this increase is due to intermixing of the Ag and Pd layers. © 1995

A Tactile Glove Design and Authoring System for Immersive Multimedia

This article presents a comprehensive exploration of the issues underlying haptic multimedia broadcasting. It also describes the implementation of a prototype system as a proof of concept.close61

Investigation on Low Voltage Operation of Electrovibration Display

This paper presents three methods of input voltage signals that allow low voltage operation of an electrovibration display while preserving the perceptual feel and strength of electrovibration stimuli. The first method uses the amplitude modulation of a high-frequency carrier-signal. The second method uses a dc-offset, and the third method uses a combination of the two methods. The performance of the three methods was evaluated by a physical experiment that measured and analyzed static (dc-component) and dynamic (vibratory component) friction forces and two subsequent psychophysical studies. The physical experiment showed that only the dc-offset method enabled a statistically significant increase in the static friction force between the fingertip and the surface of the electrovibration display. The static friction increase was closely related to the root mean square of input voltage level. In contrast, all of the three methods increased the dynamic friction force significantly, which was deemed to be related to the high frequency effect validated in the previous literature. The first psychophysical study showed that the three proposed methods can significantly reduce the peak-to-peak (p-p) amplitude of an input voltage signal while generating perceptually equally strong electrovibrations to that produced by the conventional method. Using lower p-p voltage has the merits of a simpler electrical circuit and less electromagnetic noise, saving the overall system cost. Further, the perceived intensity of electrovibration was more correlated to the dynamic friction force than the static friction force. The second psychophysical study was a discrimination experiment, and it demonstrated that all the three proposed methods and the conventional method can provide perceptually similar stimuli despite their different signal forms and voltage amplitudes. Our experimental investigation allowed us to conclude that the dc-offset method is the best way to lower the driving voltage of an electrovibration display while providing perceptually equivalent electrovibrations.115sciescopu