Tomohiro Amemiya

Lead-me interface for a pulling sensation from hand-held devices

When a small mass in a hand-held device oscillates along a single axis with asymmetric acceleration (strongly peaked in one direction and diffuse in the other), the holder typically experiences a kinesthetic illusion characterized by the sensation of being continuously pushed or pulled by the device. This effect was investigated because of its potential application to a hand-held, nongrounded, haptic device that can convey a sense of a continuous translational force in one direction, which is a key missing piece in haptic research. A 1 degree-of-freedom (DOF) haptic device based on a crank-slider mechanism was constructed. The device converts the constant rotation of an electric motor into the constrained movement of a small mass with asymmetric acceleration. The frequency that maximizes the perceived movement offered by the haptic device was investigated. Tests using three subjects showed that for the prototype, the best frequencies were 5 and 10 cycles per second.

Virtual force display: direction guidance using asymmetric acceleration via periodic translational motion

This paper describes the development of a handheld haptic display based on a new force perception method. The method uses periodic translational motion to create asymmetric acceleration leading to a virtual force vector. The method is based on the sigmoidal relationship between perception and physical quantities (tactile and proprioceptive sensations); humans more strongly feel rapid acceleration than slow acceleration. A prototype of the haptic display that generates one-directional force using a relatively simple mechanism is fabricated and evaluated. Experiments verify the feasibility of the proposed method by examining the effect of the frequency of acceleration and amplitude of the force on the perception of the virtual force vector.

Asymmetric Oscillation Distorts the Perceived Heaviness of Handheld Objects

Weight perception has been of great interest for over three centuries. Most research has been concerned with the weight of static objects, and some illusions have been discovered. Here, we show a new illusion related to the perception of the heaviness of oscillating objects. We performed experiments that involved comparing the weight of two objects of identical physical appearance but with different gross weights and oscillation patterns (vibrating vertically at frequencies of 5 or 9 cycles per second with symmetric and asymmetric acceleration patterns). The results show that the perceived weight of an object vibrating with asymmetric acceleration increases compared to that with symmetric acceleration when the acceleration peaks in the gravity direction. In contrast, almost no heaviness perception change was observed in the anti-gravity direction. We speculate that the reason for the divergence between these results is caused by the differential impact of these two hypothesized perceptual mechanisms as follows: the salience of pulse stimuli appears to have a strong influence in the gravity direction, whereas filling-in could explain our observations in the anti-gravity direction. The study of this haptic illusion can provide valuable insights into not only human perceptual mechanisms but into the design of ungrounded haptic interfaces.

Shaking the world: galvanic vestibular stimulation as a novel sensation interface

We developed a novel sensation interface device using galvanic vestibular stimulation (GVS). GVS alters your balance. Our device can induce vection (virtual sense of acceleration) synchronized with optic flow or musical rhythms. The device can also induce lateral walking towards the anode while human walking.

Orienting Kinesthetically: A Haptic Handheld Wayfinder for People with Visual Impairments

Orientation and position information are vital for people with visual impairments if they are to avoid obstacles and hazards while walking around. We develop and evaluate a haptic direction indicator that delivers directional information in real time through kinesthetic cues. The indicator uses a novel kinesthetic perception method called the pseudo-attraction force technique, which employs the nonlinear relationship between perceived and physical acceleration to generate a force sensation. In an experiment, we find that the haptic direction indicator allowed people with visual impairments to walk safely along a predefined route at their usual walking pace without any previous training, independent of the existence of auditory information. The findings indicate that the haptic direction indicator is effective at delivering simple navigational information, and is a suitable substitute for and/or enhancement to conventional wayfinding methods.

Phantom-DRAWN: direction guidance using rapid and asymmetric acceleration weighted by nonlinearity of perception

This paper describes the design of a novel force perception method and the development of a handheld force display based on the method. The method is based on the nonlinear characteristics of human tactile perception; humans feel rapid acceleration more strongly than slow acceleration. The method uses periodic prismatic motion to create asymmetric acceleration leading to a virtual force vector. A prototype of the handheld force display that generates one-directional force using a relatively simple mechanism was built, and its performance tested in terms of both physical and perceptual characteristics. We verify the feasibility of the proposed method through experiments that determine the displays motors rotational frequency that maximizes the perception of the virtual force vector.

Design of a Haptic Direction Indicator for Visually Impaired People in Emergency Situations

Some emergency situations, such as fires or earthquakes, require that evacuation to a safe area, often through an emergency exit. This is especially difficult for people with visual disability. Here, we propose a new device, a haptic direction indicator, which will help blind pedestrians intuitively and safely escape from dangerous area by means of haptic navigation.

Tactile duration compression by vibrotactile adaptation

In the visual modality adaptation to high temporal frequency can result in spatially localized apparent duration compression. The principal point of adaptation is thought to be early in the visual system, at which point temporal information is encoded within sustained (parvocellular) and transient (magnocellular) channels. Here, we investigate whether the adaptation-based time compression could also be found in the tactile modality, which also has sustained (slowly adapting) and transient (rapidly adapting) neural channels. Our results showed that periods of vibration seem compressed when presented to a region of the skin surface adapted earlier to higher frequencies. This finding indicates that human duration perception can be altered by adaptation of temporal sensory channels in similar ways in vision and touch.

Directional Force Sensation by Asymmetric Oscillation From a Double-Layer Slider-Crank Mechanism

By subjecting a small object in a handheld device to periodic translational motion with asymmetric acceleration (accelerated more rapidly in one direction than in the other), the holder typically experiences the kinesthetic illusion of being pushed or pulled continuously by the held device. We have been investigating the effect because of its potential application to a handheld, nongrounded, haptic device that can convey a sense of a continuous translational force in one direction. A one-degree-of-freedom haptic device based on a double-layer slider-crank mechanism was constructed based on the results of our previous research. Our results with the new haptic device show that (i) humans perceive directed force sensation by asymmetric oscillation, (ii) 5 counts/s is the best frequency to generate the force sensation, (iii) the ratio of the gross weight of the device and the weight of the reciprocating mass should be at least 16% for effective force perception, and (iv) the force perception is the same with the device held in either hand.

Location-free haptic interaction for large-area social applications

In this paper, we discuss the potential of force perception technologies for realizing hand-held devices in the field of social systems. We propose and develop an interactive force-sensation-based navigation system for waiters based on a force perception technology that we have proposed. The navigation system consists of our new hand-held haptic interface and a camera-based position and posture identification system. Since the proposed compact haptic interface does not require external grounding, it can be used outside the laboratory and does not interrupt human activity. We verify the feasibility of the system in trials where we collected the responses of system users.