Haptic perception of viscous friction of rotary switches

2007

Vehicle drivers receive haptic feedback in response to their movement of the steering wheel and tactile feedback from various sources of vibration of the steering wheel, with the sensations varying depending on the frequency and the magnitude of the movements. From an experiment with 12 subjects, equivalent comfort contours were determined for vertical vibration of the hands with three grip forces. The perceived intensity of vibration on a rigid steering wheel was determined using the method of magnitude estimation at seven frequencies (4 to 250 Hz) over a range of vibration magnitudes (0.1 to 1.58 ms- 2 r.m.s). The comfort contours strongly depended on vibration magnitude, indicating that a frequency weighting for predicting sensation should be dependent on vibration magnitude. At low magnitudes, increased grip force increased sensitivity at high frequencies and enhanced the frequency-dependence of the equivalent comfort contours. The results may be explained by the characteristics of the Pacinian and non-Pacinian tactile channels in the glabrous skin of the hand

Journal of Engineering Design, 2019

Designing automotive Human-Machine Interfaces falls into a resourceintensive and iterative prototyping process. Design inputs, including those resulting from an automaker's brand sense, frequently emerge from subjectively evaluating the products. This research aims at characterising the haptic feedback afforded by push-buttons' prototypes. It introduces quality criteria, by assessing feedback degradation when actuations depart from optimal conditions and fall into suboptimal interactions. From reviewing published literature in HMIs', metrics for characterising haptic profiles are insufficient and the taxonomy is unclear, redundant and conflicting. Experiments were built, providing prototypes with distinguishable feedbacks. Their haptic profile was measured and translated into unique engineering parameters, including new metrics to address feedback resilience in suboptimal actuations. Perceptual processes are involved, with the interpretation of data extended by using human Just-Noticeable-Differences (JNDs) thresholds and a psychophysical model of finger compliance. The outcome of this research is twofold: a contribution to a better understanding of pushbuttons haptic feedback, enabling the definition of desired interactions and meeting brand sense expectations in early design stages of HMIs; and a proposed taxonomy for characterising pushbutton haptic feedback. The results achieved and the research methodology are extendable for similar design activities that require Human-Machine interactions, development of HMIs in general, and virtualisation of haptics.

… and Symposium on …, 2009

Effects of Haptic Device Attributes on Vibration Detection Thresholds Curt Salisbury∗ BioRoboticsLaboratory Stanford University, USA R. Brent Gillespie† The Haptix Laboratory University of Michigan, USA ... Federico Barbagli§ BioRobotics Laboratory Stanford University, USA ...

AutomotiveUI 2009, 2009

IEEE Transactions on Haptics, 2009

acceptance by K. Kahol, V. Hayward, and S. Brewster. For information on obtaining reprints of this article, please send e-mail to: [email protected], and reference IEEECS Log Number

Frontiers in human neuroscience, 2017

This study was conducted to identify characteristics of the perceptual threshold level and electroencephalogram (EEG) responses to vibrotactile stimulations at various high frequencies, and to examine the possibility of distinguishing vibrotactile stimulations by frequency through such response characteristics. The vibrotactile stimulations of six frequencies (150, 200, 225, 250, 275 and 300 Hz) were exerted on the first joint of the right index finger. The perceptual threshold level was defined as the first minimum perceived intensity when the intensity stimulation was exerted step by step at each vibration frequency. EEG response characteristics were investigated by examining a single index corresponding to the peak or area of event-related desynchronization/synchronization (ERD/ERS) and seven specific indices derived by combining the single ERD/ERS indices. There was a significant difference in the perceptual threshold level across different frequencies. Specifically, the differe...

IEEE Transactions on Haptics, 2008

We report three experiments on manual detection of torque variations experienced through a rotary switch. The experiments were designed to investigate whether torque perception was determined by the spatial or by the temporal characteristics of the rotary switch. In Exp. I, manual detection thresholds of torque variation were measured with raised sinusoidal torque profiles that varied in spatial period from 2.8deg to 180deg per cycle. In Exp. II, the same was measured for torque profiles that varied in temporal frequency from 2 to 300 Hz. Exp. III was similar to Exp. 1 except that the participants were required to turn the rotary switch at two different speeds for each of seven spatially specified torque profiles (spatial period: 2.8deg to 90deg per cycle). A comparison of the thresholds obtained in Exp. III and those in Exps. I and II suggests that the detection of torque variations depends on the spatial, not temporal, specification of the torque profiles. Our results can potentially shed new light on the design and engineering specification of rotary switches.

IEEE Transactions on Haptics, Vol. 11, No. 4, pp. 599-610, 2018

To render tactile cues on a touchscreen by friction modulation, it is important to understand how human perceive a change in friction. In this study, we investigate the relations between perceived change in friction on an ultrasonically actuated touchscreen and parameters involved in contact between finger and its surface. We first estimate the perceptual thresholds to detect rising and falling friction while finger is sliding on the touch surface. Then, we conduct intensity scaling experiments and investigate the effect of finger sliding velocity, normal force, and rise/fall time of vibration amplitude (transition time) on the perceived intensity of change in friction. In order to better understand the role of contact mechanics, we also look into the correlations between the perceived intensities of subjects and several parameters involved in contact. The results of our experiments show that the contrast and rate of change in tangential force were best correlated with the perceived intensity. The subjects perceived rising friction more strongly than falling friction, particularly at higher tangential force contrast. We argue that this is due to hysteresis and viscoelastic behavior of fingertip under tangential loading. The results also showed that transition time and normal force have significant effect on our tactile perception.

2008 IEEE International Conference on Robotics and Automation, 2008

Haptic interfaces are used increasingly in medical systems and related applications, but relatively little is known on the effectiveness of these interfaces. This paper reports a study on the perception of haptic force magnitude during hand movements. Discrimination thresholds were determined for a reference force of 1.5N in five different directions (0 • , 45 • , 90 • , 135 • , and 180 •) with respect to the movement direction. We found that force discrimination thresholds detected were significantly higher during hand movement than those reported previously without hand movement, indicating that the perception of force magnitude is impaired by hand movement. The results also show there is no significant difference between the discrimination thresholds found for fast (28mm/s) and slow (14mm/s) hand movements. Finally, we found that the perception of force magnitude is impaired at a force direction of 45 • with respect to the hand movement, indicating the existence of an oblique effect.

2021

In times of digitalization as a megatrend, haptic feedback by touch or contact interfaces can be a means to relieve the driver/passenger on other channels of perception while communicating relevant information. In this context, the perceived comfort of haptic systems is particularly important to ensure the best possible user product interaction. Two ergonomic cross-sectional studies from the automotive and forklift sectors are presented in this contribution. The first study involved the randomized assessment of three different haptic center console devices for automotive applications in a laboratory environment. 21 subjects tested the different devices, which had three activation thresholds of 0.3N/1.0N/2.0N. The second study analyzed haptic feedback in terms of an indication and attention signal in different seats for forklifts. The tested expert group encompassed 8 subjects in the static laboratory study and 4 subjects in the field tests. The results of the first study showed for ...

2003

Switches are everyday objects that interface humans to many functionalities and influence our perception of the machinery that they are attached to. This study is aimed at a better understanding of the perceptual attributes of switches. Specifically, the perceptual thresholds for dynamic changes in a rotary switch were evaluated in two experiments using an adaptive procedure. Exp. I measured human's ability to detect the presence of a random noise superimposed on a sinusoidal torque vs. angular position profile. The detection thresholds were found to be in the range 1−3% of the peak torque. This high sensitivity was interpreted as being consistent with the existing literature in that humans are more sensitive to stimulation at high frequencies than that at low frequencies. Having established the importance of switch dynamics in its perception, Exp. II measured detection thresholds for sinusoidal torque variations with spatial frequencies ranging from 2.8° to 180°. Average thresholds varied from 0.37 to 26.17% of the average torque (30 N⋅mm) over the aforementioned spatial frequency range. These experiments provide quantitative results on our ability to detect dynamic events in a rotary switch. They shed new insight on the design and specification of rotary switches.

Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 2005

A study was performed to investigate the human ability to detect road surface type on the basis of the associated steering wheel vibration feedback. Tangential direction acceleration time histories measured during road testing of a single mid-sized European automobile were used as the basis for the study. Scaled and frequency-filtered copies of two base stimuli were presented to test subjects in a laboratory setting during two experiments that each involved 25 participants. Theory of signal detection (TSD) was adopted as the analytical framework, and the results were summarized by means of the detectability index d' and as receiver operating curve (ROC) points. The results of the experiment to investigate the effect of scaling suggested monotonic relationships between stimulus level and detection for both road surfaces. Detection of the tarmac surface improved with reductions in acceleration level, while the opposite was true of the cobblestone surface. The ROC points for both s...

… on Hand-Arm Vibration, Bologna, Italy, …, 2007

The present study has established equal sensation curves for steering wheel handarm rotational vibration. Psychophysical response tests of 20 participants were performed using the category-ratio Borg CR10 scale procedure. The test stimuli used were sinusoidal vibrations at 22 third octave band centre frequencies in the range from 3 to 400 Hz, with amplitudes in the range from 0.06 to 30 m/s 2 r.m.s. A multivariate regression analysis was performed on the mean Borg CR10 intensity values as a function of the two independent parameters of the vibration frequency and amplitude. The results suggested a nonlinear dependency of the perceived intensity on both the steering wheel rotational vibration frequency and amplitude. A sixth-order polynomial model has been proposed as a best fit regression model.

Arquivos de Neuro-Psiquiatria, 2015

Objective Hand sensory tests do not consider distinct physiological receptors, nor detect normal range variations concerning developmental or pathological changes. We developed an instrument with a set of tests with timing and scoring for assessing haptic perception, which is the interaction between sensory and motor systems, in surfaces exploration, by moving hands. Method Firstly, group meetings were set for test/manual conception and materials testing. The test/manual were submitted to 30 reviewers in 3 stages (10 reviewers on each stage). Results The Hand Haptic Perception Instrument (HHPI) evaluates hand sensorimotor performance on six domains: depression, elevation, texture, compressibility, weight (barognosis) and form perception. Each domain requires specific materials. Score ranges from 0 to 57, being 0 the worst rating. Conclusion This methodological process allowed the development of six domains and instructions to assess haptic perception. This version of HHPI is a pilot...

Springer Series on Touch and Haptic Systems, 2014

Traditional psychophysical methods are so-called because some physical dimension is carefully manipulated while people make judgments of its psychological impact (see Chap. 1). Typical psychophysical measures are: the detection threshold (minimum stimulus intensity required for conscious perception), the discrimination threshold or Just Noticeable Difference (JND; minimum difference in intensity required for discrimination), and parameters of the function relating perceived intensity to physical intensity across a range of values on the target dimension. Early attempts to measure these psychophysical variables tended to focus on univariate quantities. Thus, for example, one can find values for the threshold intensity of physical dimensions such as length, brightness, or weight, as well as other quantitative dimensions with less obvious physical interpretations such as salt dilution or voltage of a current applied to the skin (see . One can also find, from so-called magnitude estimation tasks, that perceived stimulus magnitude tends to be related to physical signal intensity in the form of a logarithmic function (Fechner 1860) or a power function, the exponent of which provides a summary measure of the perceptual transduction output for a given dimension . The present chapter focuses on stiffness, the mathematical inverse of compliance. Stiffness is inherently a higher-order property, in the sense that it is computed from the relation between two underlying quantities. By Hooke's Law, stiffness (denoted k) is the relation between displacement (d, change in position or length) and the force that produces that displacement (F), as specified by the equation, F = kd. Given that stiffness is defined by the ratio of two physical variables, force and posi-