Michi Sato

Development of a head rotation interface by using Hanger Reflex

When a head is equipped with a hanger made of wire sideways, and its temporal region is sandwiched by the hanger, the head rotates unexpectedly. We named the phenomenon “Hanger Reflex”, and we have studied this phenomenon to understand its mechanism and to show the possibility of utilizing the phenomenon as a human interface. However, to use it as an interface, pain sensation induced by the hanger becomes a practical problem. In this paper, we determined the necessary conditions of the Hanger Reflex, and we developed an interface that can induce head rotation by using the Hanger Reflex, without giving pain to the user.

Augmentation of material property by modulating vibration resulting from tapping

We present a new haptic augmented reality system that modulates the perceived stiffness of a real object by changing the perceived material with vibratory subtraction and addition. Our system consists of a stick with a vibrotactile actuator and a pad with an elastic sheet. When a user taps the pad, the innate vibration resulting from the tapping is absorbed by the elastic surface. Simultaneously, the vibrotactile actuator provides the intended vibration, which represents a modulated perceived material property such as rubber, wood, or aluminum. The experimental results showed that the participants were able to discern the three materials by tapping.

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.

Ants in the Pants

Nobody likes to imagine that insects are crawling over them. Many of us would become horrified to realize that a feeling ticklishness on the skin was caused by insects. However, many of us have had the experience of playing with ants when we were children. This might indicate that an apparently disagreeable sensation can sometimes changes to being a funny, thrilling, or even a pleasant experience. The aim of our work is to highlight this fact, and to create a new entertainment that we have, named “Ants in the Pants” (Figure 1). This is a system composed of a visual display with a touch senor and a wearable tactile display.

“Hanger reflex”:A reflex motion of a head by temporal pressure for wearable interface

When a head is equipped with a clothes hanger made of wire sideways, and its temporal region is sandwiched by the hanger, the head rotates unexpectedly. Although this phenomenon is widely known, the mechanism that underlies this phenomenon is not well understood. This paper aims to understand the mechanism, and further show the possibility to utilize the phenomenon as a human interface.

Effect of Hanger Reflex on walking

Application of the Hanger Reflex to walking navigation was investigated. The Hanger Reflex is a phenomenon that produces an illusory force and involuntary rotation of the body parts by skin deformation. It was first applied at the head by using a wire hanger, but is now known to work on many body parts such as the waist, wrist, and ankle. In the first experiment, we confirmed that the Hanger Reflex at the waist significantly affects walking direction. In the second experiment combining Hanger Reflex devices at the head, waist, and ankle, we confirmed that the waist application is most effective, and that combined Hanger Reflex imparted limited influence on the results.

Ants in the Pants -ticklish tactile display using rotating brushes-

We created a new entertainment called ldquoAnts in the Pantsrdquo. A user can see many ants moving around on a visual display. The userpsilas hand is placed into a tactile display in the form of a glove that has a matrix of small motors with brushes inside it. When the user places their gloved hand on the visual display, the user can feel a sensation as if ants are crawling up their arm. We have tested the system with more than 500 participants. In response to a questionnaire, about 75% of users responded that the experience was ldquoenjoyablerdquo and 54% that it was ldquorealisticrdquo. Moreover, our work was able to entertain most people regardless of their reaction to the experience. We believe our ldquoAnts in the Pantsrdquo opened the door to a new type of ldquouncomfortable, creepy but enjoyablerdquo entertainment.

Judged Consonance of Tactile and Auditory Frequencies

With the aim of augmenting auditory sensation by tactile stimuli, we investigated cross-modal relationships between the two modalities, focusing on frequency. The results showed that frequency consonance between tactile and audio stimuli depends on the relationship between harmonics, in a manner similar to auditory waves, but with broader peaks.

Periodic tactile feedback for accelerator pedal control

Sensing the position and movement of the accelerator pedal in a vehicle is important for acceleration control and safety while driving. The accelerator pedal is controlled by the foot, but precise adjustment requires much training because the driver must rely on somatosensory cues, which provide limited feedback. In this study, we propose periodic tactile feedback for the accelerator pedal to provide an additional tactile cue. We conducted an experiment using a driving simulator to compare the lap time, the rate of off-track incidents and the subjective evaluation of controllability recorded in questionnaires. The experiment confirmed that the feedback makes the control of acceleration easier and facilitates safer driving.

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.