A multi-modal display, including vision, audition, and touch, is generally believed to enhance human task performance (e.g., virtual surgery). However, the empirical validation of the enhancement for the inclusion of touch in a multi-modal display is less established as compared with vision and audition. Here, in a series of psychophysical experiments, we investigated how human participants integrate dynamic information between vision and touch in a virtual reality environment. We presented an autonomous deformation of a virtual object, and observers were asked to estimate the amount of deformation through vision, touch, or both. In Experiment 1, we validated that multi-modal integration can be described by a computational model based on weighted linear summation. A multi-modal display of dynamic information increased the perceptual accuracy when compared to a uni-modal display. The relative weight to each modality was influenced by the relative accuracy of each modality, although the weights were individually biased for each participant. In Experiment 2, we showed that the participants were capable of controlling the weight for each modality, leading to a reduction of the bias and an increased perceptual accuracy. These results imply that a multi-modal display including touch has the potential to enhance task performance by increasing perceptual accuracy, but also that individual difference such as perceptual strategy(i.e., biased weight)must be controlled for to maximize the benefit of a multi-modal display.

This paper describes the design of the vibration frequency for vibration alert interface when user's grip force change. Vibration alert interface conveys the information to the user by using vibration frequency. In the case of handheld obstacle sensor, perception of vibration was changed by change in grip force. User perceived distance closely when grip force became strong. We proposed correction formula of frequency based on skin deformation of finger because skin of finger was deformed by change in grip force. User can perceive the correct distance from vibration by using correction formula even when grip force change.

The mirror interface can be used for various environments and be expected as an intuitive input method for diverse users. Visual and auditory feedbacks are used for the traditional mirror interface. In this study, in addition to these feedbacks, a tactile feedback is adopted to improve the usability of mirror interface. Experiments were conducted to evaluate the influence of visual, auditory, or tactile feedback delay on the usability of mirror interface. As a result, tactile feedback did not affect the task completion time. However the delay of tactile feedback was easier to be noticed by the user than the delay of auditory feedback. Furthermore, it was found that the tactile feedback might give the user a certain feeling of selecting the desired target.

Recently, the computers and digital Information, such as Web pages, have been becoming inaccessible to the visually impaired, since they are becoming more visual and complicated. In this paper, we propose a novel information display method using a tactile and jog dial (TAJODA) interface for the visually impaired. The proposed method consists of presentation of verbal information in the form of acoustic modality and presentation of nonverbal information in the form of tactile modality. With the real-time speech rate control function and tactile vibrating patterns of the tactile display, the multimodal display method using TAJODA enables the visually impaired to search text information quickly and accurately.

This paper describes the study on hardness perception of human fingers in order to find required system performance for haptic devices that can render hard objects. Three psychophysical experiments were carried out using an apparatus that simulate different hardness levels by reproducing the trajectory of finger colliding with a virtual object. For a device to render very hard objects, the position control cycle should be shorter than 40 ms, the maximum acceleration should be at least 50 mis2 and the overshoot of finger position should be shorter than 2 mm.

In this paper, we propose a haptization method that enables a user to obtain information of flow field distribution in a three dimensional space. The proposed method defines a plane probe, which is manipulated by a user and interacted with fluid data. The plane probe enables the user to feel not only asymmetry of flow distribution, but also the change of its reaction by active manipulation of probing angle. The developed method was applied to several standard steady flow datasets. The result showed that the proposed method can represent reaction forces and torques corresponding to the distribution of each flow field. The effectiveness of the method in a 3D pointing task was examined. The result showed that the proposed system reduces a position error of the pointing task.

Spatially distributed tactile information is essential for dexterous operation in telexistence. In this study, we propose a transmission system of spatially distributed tactile information using a finger-shaped GelForce and an electrotactile display that we have developed. Because the finger-shaped GelForce consists of elastic body, it can mimic the deformation of human finger on measuring information. The electrotactile display is suitable for presenting tactile information to user's fingers, because it does not need any actuators to present tactile information. We improved the softness of the finger-shaped GelForce and realized a one-fingered transmission system of the proposed method. We evaluated a spatial resolution of the constructed system from three discrimination experiments. From the result, we estimated the current limit to improve the spatial resolution of the proposed system. Furthermore, we confirmed that the proposed system can be efficient for the multi-fingered telexistence system.

In this study, in order to define the influence of the type of touching motion on the hardness sensation of an elastic object, we conducted an experiment to compare the hardness sensation experienced on performing two different touching motions (pinching and pushing) by the method of successive categories. In this experiment, we used 14 elastic test-pieces with different hardnesses as the presented stimuli. Eleven participants were asked to rate the hardness of the presented stimuli on a seven-point scale extremely soft, fairly soft, slightly soft, neither, slightly hard, fairly hard, and extremely hard‐when touching the test-pieces with their forefinger by pushing and pinching motions. The results indicated that the hardness sensation in the case of pinching motion was softer than that in the case of pushing motion when the hardness of the elastic object was categorized as extremely soft or hard. In addition, the type of touching motion influenced the hardness sensation.

In the conventional file sharing support systems, users have to predetermine which files should be uploaded from their own PC. For this reason, other members can only get useful information from the limited contents in the uploaded files. There might be useful information in the files that are dismissed by the owner. In this paper, a new file sharing system that automatically accesses to the dormant files which are relevant to the upload files is proposed. As a result of evaluation experiments, the system promotes accessing to the dormant files, and the effectiveness of proposed system was confirmed.

The objective of this study was to clarify the influence of stimulus characteristics expressed as duration and inter stimulus onset interval(ISOI)to the perception of velocity when a set of successive tactile stimuli were given. The study also aimed at clarifying the effectiveness for the presentation using tactile apparent motion to contribute to the accurate perception of velocity. A total of 10 healthy subjects participated in the study. A set of airjet based tactile stimuli were given at their left fingers and their perceived velocities were collected by using cross-modality matching. By controlling stimulus characteristics, the accuracy of perceived velocity was compared, between the conditions whether or not tactile apparent motions were present. The results revealed that the duration, as well as ISOI, was a significant factor to contributing to the changes in perceived velocity. Empirical results showed that the perceived velocity obtained in the experiment and the velocity estimated by Kolers' equation was well deviated so that the Kolers' equation, which has been known as a good estimator for perceived velocity for visually presented moving stimuli, was not appropriate in the modality of tactile motion perception. The factor of duration was only effective under the condition of apparent motions, specifically in the case between 30ms and 70ms of ISOI. In conclusion, presentation of apparent motion for the purpose of transmitting velocity information to the user by tactile display was effective to present precise velocity information.

There is little reported in the literature on how users strategize when group priorities and individual priorities conflict and need to be balanced for a successful collaboration. We conducted an observational study on three digital tabletop systems and a real-world setup to investigate similarities and differences in these collaborations. Our results show that in the real world, these collaborations involves three phases: identifying the right timing, using epistemic actions to consider a task plan and evaluating the value of the negotiation. And we identify implications for the design of digital tabletops that arise from our findings; support creation of personal spaces, support flexible and fluid transition between spaces, tabletop systems should be sensitive to body and hand gestures, and provide greater support for epistemic actions.

Steering reactive torque presentation is one of driving support systems for a steer-by-wire(SBW) vehicle, and it would inform the road surface condition and the working state of the system. However, driver's sensory characteristics for the steering reactive torque are not known very well, and therefore, the steering reactive torque gain is decided by trial and error. The present paper performs experiments using a haptic interface which can provide arbitrary steering reactive torque to subjects, and it would elucidate the haptic characteristics for the change of the steering reactive torque in the case of a periodic steering and a constant steering. Moreover, the driving simulator experiments which simulate the actual driving environment are performed to verify the effect of the steering reactive torque amplitude on the driving behavior and the subjective evaluation.