Vibration Influences Haptic Perception of Surface Compliance During Walking

Abstract

BackgroundThe haptic perception of ground compliance is used for stable regulation of dynamic posture and the control of locomotion in diverse natural environments. Although rarely investigated in relation to walking, vibrotactile sensory channels are known to be active in the discrimination of material properties of objects and surfaces through touch. This study investigated how the perception of ground surface compliance is altered by plantar vibration feedback.Methodology/Principal FindingsSubjects walked in shoes over a rigid floor plate that provided plantar vibration feedback, and responded indicating how compliant it felt, either in subjective magnitude or via pairwise comparisons. In one experiment, the compliance of the floor plate was also varied. Results showed that perceived compliance of the plate increased monotonically with vibration feedback intensity, and depended to a lesser extent on the temporal or frequency distribution of the feedback. When both plate stiffness (inverse compliance) and vibration amplitude were manipulated, the effect persisted, with both factors contributing to compliance perception. A significant influence of vibration was observed even for amplitudes close to psychophysical detection thresholds.Conclusions/SignificanceThese findings reveal that vibrotactile sensory channels are highly salient to the perception of surface compliance, and suggest that correlations between vibrotactile sensory information and motor activity may be of broader significance for the control of human locomotion than has been previously acknowledged.

SoleSound: Towards a novel portable system for audio-tactile underfoot feedback

“…Unlike in that study, however, in this work significant alterations of subjects' natural step length and stride time were detected for both the harder and the softer simulated surfaces, which might indicate that concurrent auditory and vibrotactile ecological feedback are more effective than auditory feedback alone in impacting subjects' gait. This observation is also in accordance with findings by Visell et al on the importance of plantar vibrotactile stimuli in influencing a walker's perception of the floor compliance [18].…”

“…Most existing instrumented shoes use headphones to convey auditory feedback [3], [4], [10], [11], [13], [18]. While this solution may increase a user's sense of immersion, it is obtrusive and does not resemble real walking conditions, where sounds are generated at foot level by the interactions between the shoe sole and the ground.…”

“…Compared to discrete feedback, the latter can convey a wider range of information, and is thought to induce stronger motivational and emotional effects which may be beneficial for patients [17]. There is evidence that the rendering of different ground surface compliances through sonification of footsteps [10], vibrotactile feedback [18] and combination thereof [12] can alter the gait of healthy subjects, suggesting that such approaches can be transferred to the clinical setting. In a 2012 study, Rodger et al tested a system that used force plates and motion capture to sonify gait with PD patients and found that it reduced variability in gait [4].…”

Compressibility and Crushability Reproduction through an Amorphous Haptic Interface

“…While the reproduction of the oscillatory components alone via hard surfaces may be sufficient to determine vivid perceptual outcomes [8,9], another haptic simulation approach, proposed here, involves the artificial reproduction of the sensory experiences resulting from squeezing actions performed via a deformable haptic interface. This can reproduce a range of mechanical responses, e.g.…”

Implementation and Characterization of Vibrotactile Interfaces

“…Recently, several studies have been conducted on the use of vibratory cues as a sensory substitution method to convey pseudo-haptic effects, e.g., to simulate textures [2,26], moving objects [43], forces [14,25,29,35], or alter the perceived nature and compliance of materials [30,32,41]. Other studies exist that assessed intuitiveness of vibrotactile feedback with untrained subjects [21] and how it may improve user performance after training [38].…”