Perceived Vibration Strength in Mobile Devices: The Effect of Weight and Frequency
ABSTRACT This paper addresses the question of strength perception for vibration signals used in mobile devices. Employing devices similar to standard cell phones and using pulsed vibration signals to combat adaptation effects, experiments were performed to study the effect of weight and underlying on perceived strength. Results shows that for the same measured acceleration on the device, a heavier box is perceived to vibrate with greater strength. Furthermore, signals with higher underlying frequency are perceived to be weaker for the same measured acceleration. While our results are consistent with previous studies, they are obtained for the specific condition of ungrounded, vibrating objects held in the hand. Our results suggest the need for a systematic correction law for use by designers to specify the vibratory characteristics of a device as a function of its weight and of the desired operating frequency.
[Show abstract] [Hide abstract]
ABSTRACT: Vibrotactile rendering is one of the most popular means for improving the user interface of a mobile device, but the availability of related perceptual data that can aid vibrotactile effect design is not currently sufficient. The present paper reports data from a series of psychophysical studies designed to fill this gap. In Experiment I, we measured the absolute detection thresholds of sinusoidal vibrotactile stimuli transmitted to the hand through a mobile phone. Stimuli were generated by a mechanical shaker system that can produce vibrations over a broad frequency and amplitude range. The detection thresholds reported here are a new addition to the literature, and can serve as a baseline for vibrotactile stimulus design. In Experiment II, we estimated the perceived intensities of mobile device vibrations for various frequencies and amplitudes using the same shaker system. We also determined a form of parametric nonlinear function based on Stevens' power law and fit the function to the measured data. This psychophysical magnitude function, which maps vibration frequency and amplitude to a resulting perceived intensity, can be used to predict the perceived intensity of a mobile device vibration from its physical parameter values. In Experiment III, we measured another set of perceived intensities using two commercial miniature vibration actuators (vibration motor and voice-coil actuator) in place of the mechanical shaker. The purpose of this experiment was to evaluate the utility of the psychophysical magnitude function obtained in Experiment II, as vibrotactile stimuli produced by miniature actuators may have different physical characteristics, such as vibration direction and ground condition. Comparison of the results of Experiments II and III confirmed that the psychophysical magnitude function can reliably predict changing trends in the perceived intensity of mobile device vibration. We also discuss further research issues encountered during the investigation. The results presented in this paper may be instrumental in the design of effective vibrotactile actuators and perceptually-salient rendering algorithms for mobile devices.Presence Teleoperators & Virtual Environments 08/2010; 19(4):364-387. DOI:10.1162/PRES_a_00011 · 0.91 Impact Factor
Conference Paper: Vibrotactile stimulation can affect auditory loudness: a pilot study[Show abstract] [Hide abstract]
ABSTRACT: Very few cases have been reported where tactile stimulation affects auditory perception. In this pilot study, we asked volunteers to compare the loudness of combinations of vibrotactile and auditory stimuli. A 50-300 Hz band-limited pink noise signal was used as the stimulus in the two modalities, simultaneously heard through headphones and felt in the hands to be compared to when it was heard only. On average, the same auditory stimulus was judged to be about one dB louder when it was simultaneously heard and felt rather than when it was heard only. This condition could be interpreted as having enhanced the perception of loudness by a whole jnd.Proceedings of the 2012 international conference on Haptics: perception, devices, mobility, and communication - Volume Part II; 06/2012
[Show abstract] [Hide abstract]
ABSTRACT: This study investigates the effect of mechanical ground on the perceived intensity of vibration transmitted through a handheld object. To this end, we carried out an intensity matching experiment in which the points of subjective equality were measured between grounded and ungrounded conditions. Results showed that the grounded vibrations were perceived to be 1.63---1.86 times stronger than the ungrounded vibrations. This intensity difference was decreased with increasing vibration frequency. Our results are in line with the general fact that afferent movements, which are more apparent under the ungrounded condition, may induce tactile suppression.Proceedings of the 2012 international conference on Haptics: perception, devices, mobility, and communication - Volume Part II; 06/2012