Yasuyuki Yanagida

Wearable vibrotactile systems for virtual contact and information display

This paper presents a development history of a wearable, scalable vibrotactile stimulus delivery system. This history has followed a path from desktop-based, fully wired systems, through hybrid approaches consisting of a wireless connection from the host computer to a body-worn control box and wires to each tactor, to a completely wireless system employing Bluetooth technology to connect directly from the host to each individual tactor unit. Applications for such a system include delivering vibrotactile contact cues to users of virtual environments, providing directional cues in order to increase situational awareness in both real and virtual environments, and for general information display in wearable contexts. Through empirical study, we show that even a simple configuration, such as eight tactors arrayed around the torso, can be effective in increasing situational awareness in a building-clearing task, compared to users who perform the same task without the added cues.

Towards full-body haptic feedback: the design and deployment of a spatialized vibrotactile feedback system

This paper presents work we have done on the design and implementation of an untethered system to deliver haptic cues for use in immersive virtual environments through a body-worn garment. Our system can control a large number of body-worn vibration units, each with individually controllable vibration intensity. Several design iterations have helped us to refine the system and improve such aspects as robustness, ease of donning and doffing, weight, power consumption, cable management, and support for many different types of feedback units, such as pager motors, solenoids, and muffin fans. In addition, experience integrating the system into an advanced virtual reality system has helped define some of the design constraints for creating wearable solutions, and to further refine our implementation.

Vibrotactile letter reading using a low-resolution tactor array

Vibrotactile displays have been studied for several decades in the context of sensory substitution. Recently, a number of vibrotactile displays have been developed to extend sensory modalities in virtual reality. Some of these target the whole body as the stimulation region, but existing systems are only designed for discrete stimulation points at specific parts of the body. However, since human tactile sensation has more resolution, a higher density might be required in factor alignment in order to realize general-purpose vibrotactile displays. One problem with this approach is that it might result in an impractically high number of required tactors. Our current focus is to explore ways of simplifying the system while maintaining an acceptable level of expressive ability. As a first step, we chose a well-studied task: tactile letter reading. We examined the possibility of distinguishing alphanumeric letters by using only a 3-by-3 array of vibrating motors on the back of a chair. The tactors are driven sequentially in the same sequence as if someone were tracing the letter on the chairs back. The results showed 87% successful letter recognition in some cases, which was close to the results in previous research with much larger arrays.

Empirical studies for effective near-field haptics in virtual environments

This paper presents results from two experiments into the use of vibrotactile cues for near-field haptics in virtual environments. In one experiment, subjects were tested on their ability to identify the location of a one-second vibrotactile stimulus presented to a single tactor of a 3-by-3 array on their back. We recorded an 84% correct identification rate. In a second experiment, subjects were asked to match the intensity of a vibrotactile stimulus presented at one location with the intensity at another location. We found that subjects could match the intensities to within 7Hz if the reference and adjustable stimuli were presented at the same location, but only to within 18Hz otherwise.

The TactaPack: A Wireless Sensor/Actuator Package for Physical Therapy Applications

In this paper, we present preliminary work we have done on designing the TactaPack, a wearable sensor/actuator device that uses a Bluetooth wireless connection to return sensor data to a host, and to receive commands to initiate expressive vibrotactile stimuli. We present our work in the context of a physical therapy application designed to provide more autonomy for patients when performing rehabilitative exercises. This assistive technology has the potential to reduce injuries during therapy due to improper patient joint movement, and decrease the workload of physical therapists, thereby reducing healthcare costs. Though still in the early stages of design, we believe the TactaPack can be used to produce systems that are less cumbersome than current, wired solutions, and simplify the creation of high-level applications by offloading from the CPU to the device the process of sensing, testing against threshold values, and actuation.

The Proactive Desk: a new force display system for a digital desk using a 2-DOF linear induction motor

The Proactive Desk is a new digital desk with haptic feedback. The Proactive Desk allows a user to handle both virtual and real objects on a digital desk with a realistic feeling. We proposed it for a co-experience web that would enable people to share the feelings and experiences of other users via the Internet. In the Proactive Desk, two linear induction motors are equipped to generate an omnidirectional translational force on a users hand or a physical object on the desk without any mechanical link nor wire, thereby preserving the advantages of a digital desk. In this paper we report applications of the Proactive Desk and the performance of the first trial model.

Simulating side slopes on locomotion interfaces using torso forces

This paper describes the biomechanical experimental validation of simulating side slope during walking on a treadmill style locomotion interface. The side slope effect is achieved by means of a lateral force applied to the waist of the walking subject. Results are provided and discussed for both simulated and real side slopes, showing a substantial biomechanical equivalence in the walking pattern for the real side slope and lateral torso force.

The proactive desk: a new haptic display system for a digital desk using a 2-DOF linear induction motor

The Proactive Desk is a new digital desk with haptic feedback. The concept of a digital desk was proposed by Wellner in 1991 for the first time. A typical digital desk enables a user to seamlessly handle both digital and physical objects on the desk with a common GUI standard. The user, however, handles them as virtual GUI objects. Our Proactive Desk allows the user to handle both digital and physical objects on a digital desk with a realistic feeling. In the Proactive Desk, two linear induction motors are equipped to generate an omnidirectional translational force on the users hand or on a physical object on the desk without any mechanical links or wires, thereby preserving the advantages of the digital desk. In this article, we first discuss applications of a digital desk with haptic feedback; then we mention the design and structure of the first trial Proactive Desk, and its performance.

Towards Effective Information Display Using Vibrotactile Apparent Motion

In this paper, we explore the use of tactile apparent motion at different speeds for information display. A prototype vibrotactile tactor array was constructed, consisting of three rings of five voice-coil tactors each, and mounted on the upper arm of test subjects. The results of two experiments are presented: a study on the sensitivity to differences in apparent motion speed, and a study on users’ ability to differentiate four motion patterns at three different speeds. Users had little trouble with pattern identification, but found absolute speed recognition difficult. Several ideas for future exploration of tactile apparent motion for general-purpose information displays are presented.

A survey of olfactory displays: Making and delivering scents

An olfactory display is a device that generates scents with the intended component and concentration of odor material and provides it to the human olfactory organ. In combination with an odor sensing system, an olfactory display becomes a part of system that records and reproduces odors. In this article, technologies applied to modern olfactory displays are described. First, roles of olfactory displays are categorized into three functions: making scented air from the stocked form of each odor material (vaporization), switching/blending multiple kinds of scents, and delivering scented air to the human olfactory organ. Next, detailed techniques in each category are described. A variety of techniques are applied in modern olfactory displays, each of which has both advantages and limitations. Therefore, it is important to appropriately select the combination of vaporization, switching/blending, and delivery techniques, according to the purpose and characteristics of application.