Development and evaluation of a handheld type 6 DoF midair haptic device using asymmetric vibration and a presentation force vectoring mechanism

This paper describes a handheld type aerial haptic device with 6 DoF (degree of freedom) using pseudo-haptics by asymmetric vibration. By introducing a original presentation force vectoring mechanism, 6 DoF force sense presentation and compactness suitable for handheld use with a small number of vibrators are realized together. In addition, a relationship between the drive input and output (presentation force sense) of the developed device is formulated, and its inverse problem solving method for obtaining the drive input that realizes a desired presentation force sense is derived. Furthermore, a user test clarified the direction in which this device can / cannot effectively exert force.

Effects of Asymmetric Vibration Frequency on Pulling Illusions

It is known that humans experience a haptic illusion, such as the sensation of being pulled in a particular direction, when asymmetric vibrations are presented. A pulling illusion has been used to provide a force feedback for a virtual reality (VR) system and a pedestrian navigation system, and the asymmetric vibrations can be implemented in any small non-grounded device. However, the design methodology of asymmetric vibration stimuli to induce the pulling illusion has not been fully demonstrated. Although the frequency of the asymmetric vibration is important, findings on the frequency have not been reported. In this study, we clarified the influences of the effects on the pulling illusion based on the investigation of asymmetric vibration frequency differences. Two psychophysical experiments that related to the frequency of asymmetric vibration were performed. Experiment I showed that the illusion occurs for specific vibration waveforms at 40 Hz and 75 Hz. As a result of Experiment II, the threshold was the lowest when the frequency was 40 Hz, and highest when the frequency was 110 Hz. This result supports the previous hypothesis that the Meissner corpuscles and the Ruffini endings contribute to the illusion, while the Pacinian corpuscles do not.

Nonlinear vibration of full-filled fluid corrugated sandwich functionally graded cylindrical shells

This article proposes a semianalytical approach for the nonlinear free and forced asymmetric vibration of corrugated sandwich functionally graded cylindrical shells containing fluid under harmonic radial load. The corrugation is considered with two types: trapezoidal corrugation and round corrugation. By using the Donnell shell theory, taking into account the geometrical nonlinearity of von Kármán and an equivalent model for corrugated structures, the governing equations of shell are established. The nonlinear motion equations are reduced to nonlinear differential equation in terms of time by applying the Galerkin procedure. The numerical investigations for the nonlinear dynamic response of cylindrical shells are obtained by using the fourth-order Runge–Kutta method. Numerical results show the very large effects of corrugation and fluid on the natural frequency and nonlinear vibration behavior of shells.

Effect of the vibration profile on shallow granular systems

We describe the collective behaviour of a system of many inelastic spherical particles inside a box which is being periodically vibrated. The box is shallow, with large horizontal dimensions, while the height is less than two particle diameters. The vibrations are not symmetric: the time the box is moving up is, in general, different from the time it is moving down. The limit cycles of isolated grains are largely affected by the asymmetry of the vibration mode, increasing the size in phase space of the chaotic regions. When many grains are placed in the box, the phase separation between dense, solid-like regions, coexisting with fluid-like regions takes place at smaller global densities for asymmetric vibration profiles. Besides, the order parameter of the transition takes larger values when asymmetric forcing is used.