Scale conversion telexistence is an extended concept of telexistence. It comprises avatars of different scales compared with the human scale. Immersive telexistence experience requires the avatar to realize the operator's behavior instantaneously as soon as possible. It is important to match the avatar's behavior with the operator's behavior because the difference between the operator and the avatar tends to hurt the immersiveness. However, the scale difference between an operator with the avatar makes behavior mismatch and lets the operator experience under different physical constant world. For instance, gravity changes under scale conversion telexistence. Therefore, our previous work reveals its importance termed equivalent gravity condition for walking using a small biped robot. Thus, in this demonstration, we use a small biped robot as the different-scale avatar allow us to experience as if we are within the small robot. Attendees experience several steps walking under different gravity conditions.

In this work, we proposed the control method that enable intuitive operation, “tsumori control”. Tsumori control is implemented using human discrete intention of motion included in continuous and intuitive motion output. The experience operating a robot using tsumori control will be demonstrated for our control system.

Galvanic vestibular stimulation induces virtual acceleration sensation and is expected to be applied in computer games to improve their reality. The acceleration sensation can be enhanced by giving countercurrent which consists of an opposite current part and a forwarding current part. Conventionally, however, the degree of the enhancement is uncontrollable. This study reports that the effect of countercurrent can be modeled by an electrical circuit containing a capacitor and resistors. To model the effect of the countercurrent on the acceleration perception, we investigated the relation between the parameters: the duration and the strength of the opposite current part, of the countercurrent and strength of acceleration perception. The results of our study show that the strength of the acceleration sensation induced by the countercurrent stimulation has a nonlinear correlation with the duration of the opposite current, and the characteristics of the enhancement effect can be estimated using a CR circuit model.

The mechanism by which cathodal current stimulation exerts inhibitory effects on the five basic tastes is revealed herein. The objective of this paper is to successfully achieve inhibition of sweetness by cathodal current electrical stimulation to the tongue, which has not been reported to date, though inhibition of salty and umami perception has been documented. By focusing on the electrophoresis of ions generated by dissolution of taste-inducing substances in water, this paper indicates how human gustation is inhibited by electrical stimulation, which is a key addition to the knowledgebase for achieving control of all five basic tastes.

As a low-cost information display in public spaces, we achieved a multi-slit display by the arrangement of LED columns. Multi-slits visually present an image pattern through columns of slits that are arranged several spaces wide. They cannot be perceived image by stop patterns, but they can be perceived by scroll patterns. In this paper, we experimentally show that stereoscopic vision is possible by presenting binocular parallax images that impart the beam direction from slits.

Our aim of this study is to investigate the possibility of estimating interruptibility from Electroencephalograms (EEG). We focus on contingent negative variation which is elicited in response to concentration. Our results support that our method could correctly detects the user's internal states such as just watching or actively remembering even the external situations were completely same and also CNV is elicited when controlling continuous motion.

When training for dance or sports, amateurs observe and mimic the physical exertion of experts to acquire skill by observing others. However, humans don't memorize consecutive operations, but instead make discrete divisions and memorize body movements. The posture that becomes a key from consecutive operations is removed and memorized for discretion in a process we call segmentation. The movement is reproduced by smooth interpolations between the clause and the clause memorized as segmentation. In the first experiment, we clarified the existence of this segmentation by showing video of smooth movements to participants who selected the segment/frame that became a key. We confirmed commonness in this segment selection. In experiment 2, to reflect the physical exertion that made the segmentation, the participants input force to force sensors by a control stick. We showed video of smooth movements to them and simultaneously input the force pattern that corresponds to the movement. The force pattern, which uniformly converges by such repetition, is different depending on each participant. We call this method the “extraction of segmented behavioral intention.” On the other hand, we can arbitrarily change the speed of the physical exertion by expanding and contracting the segments of the movement video that obtained the force pattern by “extraction of segmented behavioral intention.” Since the expanded and contracted pattern range at a certain speed even when the movement speed changed, we preserved the shape and the selected segments. However, the segment shape changes when the movement speed is constantly fast.

This study presents an experiment that integrates a semiotic investigation with a dynamical perspective on embodied social interactions. The primary objective is to study co-creativity of a communication system on the human-human nonverbal interaction. Throughout the experiment, the results of established communication system on uni- and bi-directional interactions are compared. Finally, the role of co-creativity in the evolution of communication systems will be discussed.

We developed a new pseudo-attraction force display using four vibrating motors. The advantage of this device is that it uses phase difference control to alter the time width of pulses to generate asymmetric oscillation. It does not require altering the frequency of the vibrating motors. In this study, we investigated the influence of the pulse width generated in the device using vibrating motors on the perceptive intensity of pseudo-attraction force. From the result, the oscillation having shorter pulse widths within the range of 10-20 ms induced the “being-pulled” sensation more strongly.

Our aim of this paper is to investigate the human communication in terms of two following questions. One is how human can know the fact that an interacting partner is human. Another is how non-communicative behaviour can become communicative. To answer these questions, we performed two experiments exploiting the idea of perceptual crossing experiments. As a result, we will show that the turn-taking structure supports humanlikeness and human communication in the primitive non-verbal interaction. Our results will be discussed with ambient interface technology.

When a single column of light sources flashes quickly in a temporal pattern during a horizontal saccade eye movement, two-dimensional images can be perceived in the space neighboring the light source. This perceptual phenomenon has been applied to light devices for visual arts and entertainment. However, a serious drawback in exploiting this perceptual phenomenon for a visual information display is that a two-dimensional image cannot be viewed if there is any discrepancy between the ocular motility and the flicker timing. We overcame this drawback by combining the saccade-based display with an electro-ocular-graph-based sensor for detecting the saccade. The saccade onset is measured with the electro-ocular-graph-based sensor in real time and the saccade-based display is activated instantaneously as the saccade begins. The psychophysical experiments described in this article demonstrates that the method that we used can detect saccades with low latency and allows the saccade-based display to convey visual information more effectively than when the light sources continuously blink regardless of the observer's eye movements.

Performing general human behavior by experts' navigation is expected to be realized as wearable and ubiquitous technologies and computing develop. For simple, ordinary behavior, a person does not need the assistance of an expert. However, if one is standing next to an injured/ill person, one needs the instruction on performing first aid treatment from an expert. The wearer of the wearable behavior navigation system will be able to conduct first aid treatment as an expert would. We have developed the wearable behavior navigation systems using Augmented Reality technology, mainly for the navigation of the first aid treatment and for escape from dangerous areas, such as a building on fire. The effectiveness of the wearable navigation systems has been evaluated by a number of experiments. In this paper, the basic mechanism to realize general human behavior navigation is presented, along with the concrete configuration of the prototype of the navigation systems, and the experimental evaluation.

This paper discusses the design of a knocking force display to induce the kinesthetic illusion of being pulled. Previously, we have found that when a hand-held object oscillates in the hand, if the acceleration pattern is lopsided, one feels a pulling force sensation, although the object does move in two opposite directions. Here, we designed and developed a new force display to generate two imbalanced acceleration patterns in opposing directions. In the display, an internal mass repetitively collides against a wall, to create a spikier pulse than the previous force display could produce. We determined the circumstances under which the sensation of being pulled was perceived by varying the pulse width, i.e., by attaching materials of different stiffnesses to the wall.

When two distant persons establish cooperative interaction, how to share their motions and sensations and how to adjust or revise their motions are important for cooperation. In this paper, we propose an approach for sharing first-person perspectives to establish collaboration and to transmit a skill from one to another. We developed a view-sharing system to realize such interaction. To investigate the fundamental behavioral property of humans with our system, we examined a simple collaborated behavior and found that a situation where subjects only see their partner's view improves velocity following. By exploiting this property, we transmitted the basic skill required for the Diabolo trick to non-skilled persons. Through our system, the performances of non-skilled persons with the assistance of a skilled person surpassed individual performances.

The capability to perform specific human tasks with the assistance of expert navigation is expected to be realized through the development wearable and ubiquitous computing technology. For instance, when an injured or ill person requires first-aid treatment, but only non-experts are nearby, instruction from an expert at a remote site is necessary. A behavior navigation system will allow the user to provide first-aid treatment in the same manner as an expert. Focusing on first-aid treatment, we have proposed and developed a prototype wearable behavior navigation system (WBNS) that uses augmented reality (AR) technology. This prototype WBNS has been evaluated in experiments, in which participants wore the prototype and successfully administered various first-aid treatments. Although the effectiveness of the WBNS has been confirmed, many challenges must be addressed to commercialize the system. The head-mounted displays (HMDs) used in the WBNS have a number of drawbacks, for example, high cost (which is not expected to decrease in the near future) and the time required for an ordinary user to become accustomed to the display. Furthermore, some individuals may experience motion sickness wearing the HMD. We expect that these drawbacks to the current technology will be resolved in the future; meanwhile, a near-future remote behavior navigation system (RBNS) is necessary. Accordingly, we have developed RBNSs for first-aid treatment using off-the-shelf components, in addition to the WBNS. In this paper, the basic mechanisms of the RBNS, experiments investigating the demonstration of expert behavior, and a comparative study of the WBNS and the RBNSs are presented.

This paper discusses the effect of acceleration profiles on the kinesthetic illusion of being pulled (pseudo-attraction force perception). We have found that when a hand-held object oscillates in the hands, if the acceleration pattern is lopsided, one feels a pulling force sensation, although the object does move in two opposite directions. Our previous findings indicate that the pulse frequency of a lopsided oscillation determines the effective generation of the pseudo-attraction force. The object of this study is to clarify the effect of pulse width and pulse interval on force perception at the pulse frequency. The experimental results suggest that (i) there were no significant difference between pulse widths as regards perceiving a pseudo-attraction force, and (ii) there was a depressive interaction between pulse width and pulse interval with respect to force perception.

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.

When a small object in a hand-held device moves periodically and prismatically with asymmetric acceleration (strong in one direction and weak in the other), the holder typically experiences the kinesthetic illusion of being pushed or pulled continuously by the held device. We investigated this perceptual effect for its potential application to a hand-held, non-grounded, haptic device that can convey a sense of a continuous translational force in one direction, which is a yet missing tile in haptics research. A one-degree of freedom haptic device based on two symmetric slider-crank mechanism was constructed to convert the single-speed rotational cyclic movement of a motor into asymmetric translational cyclic movement with asymmetric acceleration and to cancel unwanted side acceleration. We verified our previous results with the haptic device and investigated the effect of the gross weight of the device on force perception.

Artificial neural networks have been traditionally employed to learn and compute the inverse kinematics of a robotic arm. However, the inverse kinematics model of a typical robotic arm with joint limits is a multi-valued and discontinuous function. Because it is difficult for a multilayer neural network to approximate this type of function, an accurate inverse kinematics model cannot be obtained by using a single neural network. In order to overcome the difficulties of inverse kinematics learning, we propose a novel modular neural network system that consists of a number of expert modules, where each expert approximates a continuous part of the inverse kinematics function. The proposed system selects one appropriate expert whose output minimizes the expected position/orientation error of the end-effector of the arm. The system can learn a precise inverse kinematics model of a robotic arm with equal or more degrees of freedom than that of its end-effector. However, there are robotic arms with fewer degrees of freedom, where the system cannot learn their precise inverse kinematics model. We have adopted a modified Gauss-Newton method for finding the least-squares solution to address this issue. Through the modifications presented in this paper, the improved modular neural network system can obtain a precise inverse kinematics model of a general robotic arm.

This study describes the relation between the vection produced by optical flow and that created by galvanic vestibular stimulation. Vection is the illusion of self motion and is most often experienced when an observer views a large screen display containing a translating pattern. This illusion has only limited fidelity and duration unless it is reinforced by confirming vestibular information. Galvanic vestibular stimulation (GVS) can directly produce the sensation of vection.

An essential factor in understanding the motor learning capability of humans, is the coordinate transformation learning of the visual feedback controller. Although a number of learning models for the visual feedback controller have been proposed, none has been able to establish a definitive approach. In our previous work, we have suggested a learning model that uses disturbance noise and the feedback error signal to learn the human visual feedback controller's coordinate transformation. However, the model does not fully consider the time delay in the visual feedback control loop. This paper presents a modified learning model taking into account the time delay and the convergence properties of the model. Numerical simulations are presented to illustrate the effectiveness of the proposed approach.

Inverse kinematics computation using an artificial neural network that learns the inverse kinematics of a robot arm has been employed by many researchers. However, the inverse kinematics system of typical robot arms with joint limits is a multivalued and discontinuous function. Since it is difficult for a well-known multilayer neural network to approximate such a function, a correct inverse kinematics model cannot be obtained by using a single neural network. In order to overcome the discontinuity of the inverse kinematics function, we proposed a novel modular neural network system that consists of a number of expert neural networks. Each expert approximates the continuous part of the inverse kinematics function. The proposed system uses the forward kinematics model for selection of experts. When the number of the experts increases, the computation time for calculating the inverse kinematics solution also increases without using the parallel computing system. In order to reduce the computation time, we propose a novel expert selection by using the performance prediction networks which directly calculate the performances of the experts.

We have proposed and developed a tactile display that uses electrical current as a stimulus. The main characterstic of this display is that each type of mechanoreceptor is stimulated separately so that "tactile primary colors" are defined. In this paper, we describe how we fabricated a 4/spl times/4 array electrode system to present surface roughness, patterns and relative motions.

We present an autostereoscopic display named TWISTER I (Telexistence Wide-view-angle Immersive STEReoscope, Model I), which is designed for a face-to-face telecommunication system called "mutual telexistence". By rotating display units that consist of LED arrays and a barrier around a viewer, TWISTER I can display panoramic stereoscopic images that can be observed without the use of special eyewear. This "glassless" feature is essential for applying this apparatus to mutual telexistence because eye contact is important in non-verbal communication.

The authors first analyze dynamic properties of rapidly adapting mechanoreceptors in order to derive a principle of tactile displays. It is shown that Meissner corpuscles with coiled axons and Pacinian corpuscles with layered lamellae are suited to detect equivoluminal distortion of skin. Combining these analyses with a model of a contact and a relative motion between an object and the skin, it is shown that a prerequisite for tactile displays is to generate sources of shear stress that can be spatially dispersed at the skin surface and temporally modulated with a stick-slip frequency determined by parameters of the object to be displayed. As a device that satisfies this prerequisite, we propose a tactile display using Surface Acoustic Waves (SAW). The roughness of the surface can be changed continuously by controlling the burst frequency of the SAW.

In order to grasp an object, we need to solve the inverse kinematics problem, i.e., the coordinate transformation from the visual coordinates to the joint angle vector coordinates of the arm. In human motion control, the learning of the hand position error feedback controller in the inverse kinematics solver is important. Although several models of coordinate transformation learning have been proposed, they suffer from a number of drawbacks. This paper proposes a novel model of the coordinate transformation learning of the human visual feedback controller by using disturbance noise and feedback error signal. The feasibility of the proposed model is illustrated using numerical simulations.

In order to learn an inverse system of a plant, the learning method which inputs the output of the plant to the learner and uses the input of the plant as the desired output signal for the learner has been used in many researches. This learning method for learning control by using a neural network is called "direct inverse modeling" (DIM). Jordan (1995) regarded DIM as a purely off-line learning method and pointed out that DIM is not goal-directed. However, some researches have proposed a different way of using DIM. We deal with online DIM, which is the simultaneous or alternate execution of the plant control and the inverse model learning by DIM. The learning properties of online DIM is completely different from that of off-line DIM. This paper shows that online DIM becomes goal-directed under certain conditions.

Proposes a novel visuo-haptic display using a head-mounted projector (HMP) with X'tal Vision (Crystal Vision) optics. Our goal is to develop a device which enables an observer to touch a virtual object just as it is seen. We describe in detail the design of an HMP with X'tal Vision, which is very suitable for augmented reality. For instance, the HMP makes the occlusion relationship between the virtual and the real environments nearly correct. Accordingly, the user can observe his/her real hand with the virtual objects. Furthermore, the HMP reduces eye fatigue because of the low inconsistency of accommodation and convergence. Therefore, we applied HMP-model 2 to a visuo-haptic display using a camouflage technique. This technique, called optical camouflage, makes an obstacle object, such as a haptic display, become translucent. With this method, a user can observe a stereoscopic virtual object with a nearly correct occlusion relationship between the virtual and the real environments, and he can actually feel the object.

Projection-based visual display systems are expected to be effective platforms for virtual reality (VR) applications in which the displayed images are generated by computer graphics using 3D models of virtual worlds. However, these kinds of visual displays, as well as other kinds of fixed screen-based displays, such as various head-tracked displays (HTDs) and conventional CRT displays, have not been utilized to achieve precise telexistence in a real environment, which requires appropriate stereoscopic video images corresponding to the operator's head motion. We found that the time-varying off-axis projection required in these systems has prevented fixed screen-based displays from being used for telexistence, as ordinary cameras only have fixed and symmetric fields of view about the optical axis. After evaluating the problem, a method to realize a live video-based telexistence system with a fixed screen is proposed, aiming to provide the operator with a natural 3D sensation of presence. The key component of our method is a feature that keeps the orientation of the cameras fixed, regardless of the operator's head motion. Such a feature was implemented by designing a constant-orientation link mechanism.