Narihiro Nishimura

Application of Hanger Reflex to wrist and waist

When a wire hanger is placed sideways on the head, and the temporal region is sandwiched by the hanger, the head rotates unexpectedly. This phenomenon has been named the “Hanger Reflex”. Although it is a simple method for producing pseudoforce sensation, the use of the wire hanger in this way has up until now been limited in posistion to the head. Here we report a new finding that when a wrist or waist is equipped with a device of a larger circumferance the arm or the body rotates involuntarily. This fact suggests that the Hanger Reflex principle might be applicable to parts of the body other than the head, leading to the possible compact whole-body force display. This paper documents the development and testing of the devices and, suggesting stable presentation of the rotational force.

[D08] Wearable encounter-type haptic device with 2-DoF motion and vibration for presentation of friction

Summary form only given, as follows. In haptic interaction, friction caused by slip on the fingertip is a key factor for manual manipulation as well as exploration of texture and shape. From the moment of contact, the friction contains vertical and tangential skin deformations and vibrations, not all of which have been simultaneously supported by previous portable/wearable haptic devices. We propose a portable haptic device that has the ability to present skin deformation and vibration with two degrees of freedom by using two types of motors: a voice coil motor (VCM) for vertical motion and vibration, and direct current motors for tangential skin stretch. The VCM also achieves encounter-type haptic interactions. A combination of these motions encompasses most cutaneous cues for realistic friction.

Optimal selection of electrodes for muscle electrical stimulation using twitching motion measurement

Muscle electrical stimulation envisions a wide range of human augmentation application. However, the applications commonly have issue of optimal electrodes placement. In this paper, we propose a method to select the optimal electrodes placement for finger flexion using twitching motion measurement. We delivered electrical stimulation producing twitching motion and measured the acceleration. By summing and averaging the acceleration waveforms and taking the difference between the maximum and minimum value, we measured the contribution of the electrical stimulation and used it to select the optimal electrodes pair for the movement. Preliminary experiment with four electrodes showed feasibility of our method.

Perceptual Force on the Wrist Under the Hanger Reflex and Vibration

The hanger reflex is a phenomenon that accompanies illusory force sensation and involuntary head rotation when the head is fastened with a wire hanger. This phenomenon is also observed on the wrist, and is expected to apply when using small and simple haptic feedback devices. However, issues of slow response and the requirement for large actuators still remain. Here, we discuss the discovery of a new phenomenon: the perceptual force from the hanger reflex is enhanced when a vibration is also presented. If we can control the strength of the perceptual force induced by vibration, a smaller, simpler, and higher response device might be achieved, because a vibrator can be controlled easily. This paper reports details of this phenomenon, and the effect of the frequency and amplitude of the vibration on the strength of the perceptual force. We observed that low frequency 50---100i?źHz vibrations efficiently enhanced the perceptual force, and that participants perceived a stronger perceptual force if the vibration of a greater amplitude was presented. These results suggest that the enhancement of the perceptual force is controllable and can be applied to construct a new type of wearable haptic device.

[D10] Large-area tactile display using vibration transmission of jammed particles

Summary form only given, as follows. Tactile displays to enrich audiovisual experience often employ vibration feedback from a chair or jacket. Providing vibration to lager area of the human body is a promising approach to make the experience more immersive. However, the system requires many vibrotactile transducers to be applied to the whole body, and contact between the transducers and the users body surface is sometimes insufficient. We propose a novel vibrotactile display that covers a large area of the body surface and fits various shapes, based on vibration transmission through jammed particles. Styrofoam particles around the body are jammed by evacuating the air. Vibrations from speakers are delivered to the users body though the jammed particles. We envision our vibrotactile transmission Technologynique being applied to whole-body tactile displays.

Pressure Threshold of the Hanger Reflex at the Wrist

While hanger reflex is known as an involuntary movement of human head, the similar phenomenon has been found at the wrist and positions that efficiently generate the movement. However, the detailed condition about the strength of the pressure has not yet studied. In this paper, we measured the pressure thresholds of the hanger reflex at the wrist. The results showed around 6 N pressure presented both inward and outward rotation.

Evaluation of a tactile device for augmentation of audiovisual experiences with a pseudo heartbeat

The impression that the viewer has of characters is an important factor affecting the viewers opinion of audiovisual media, such as movies, television and video games. In particular, when we feel affection toward characters, we sometimes go so far as to identify ourselves as one of them, leading to extreme immersion in the content of the media. Therefore, there is the possibility that content technology can control affective feelings towards characters and create an immersive environment. We propose a device that can be used to facilitate the affection of the user by controlling their positive feelings toward characters in the media content. Previous studies have shown that emotional or physiological states can be altered by the visual and auditory presentation of false heartbeats [1, 2, 3]. However, if these techniques are applied to audiovisual media such as movies, television, or video games, the audio and visual heartbeat cues may interfere with and pollute the audiovisual content.