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Tactile sensation consists of sensory information at a contact status between human and the other environment. The contact status draws some physical phenomena. The tactile sensor has to record the sensory information, so the sensor should record these physical phenomena. The physical phenomena of the contact point are listed as follows; deformation, stress, temperature, and time variation of these information. When human touch some environment the human finger will be deformed according to the pressed force and the reactive stress from the environment. The deformation and the stress are linked together and occur according to the Young's modulus and the Poisson's ratio of materials of the finger and the environment. If the materials can be assumed to be the total elastic body, the deformation and the stress can be linked by the linear elastic theory. Because there exists no total elastic body, the link between the deformation and the stress is a little complex. The complexity is enhanced when the contact state is changed according to time. For example, the human moves his finger toward the environment or touch a vibratory environment, the environment may return the damper or mass property with the change of movement speed or acceleration. The most characteristic example is a dilatants phenomenon. A dilatants material is one in which viscosity increases with the rate of shear. As a simple environment model, there exists such an impedance model

In the field of tactile displays, electrostatic force displays have been developed for presenting tactile stimulation on a screen. However, with the conventional electrostatic force displays, the user cannot feel the stimulation without rubbing on the display. In this paper, to solve this problem, we propose a new method to present a tactile sensation without moving a finger by creating a small space between an electrode and an insulating surface. Moreover, we evaluate the perceived threshold of the proposed display through the experiment.

Nowadays, touchscreens have been used worldwide. However, most of them lack realistic haptic feedback. Several haptic feedback devices employ one-dimensional vibration only. We aim at a novel rendering method for direction-controlled 2-dimensional vibration display to present texture information. This paper proposed a rendering method of texture information that enables lateral-force-based 2-dimensional vibration in the X and Y-axis. Moreover, we proposed combining AKAZE image feature information of the textures to improve the fidelity for larger periodic textures. We held experiments to evaluate the fidelity of the proposed method. The result shows that the proposed method has higher fidelity in presenting randomized textures and large periodic textures than the conventional method.

Various methods have been proposed for collecting vibrotactile information. However, the collection procedure requires manual scanning of texture, collection of vast information may be difficult. Owing to the fast progress of machine learning technologies, even with little information, there is a possibility to generate further virtual data from existing collected data by using Generative Advisory Network (GAN). In this paper, we proposed a generation model of vibrotactile information by Deep Convolutional GAN (DCGAN) from the collected acceleration data. We generated various vibrotactile information by using the proposed DCGAN, and compared the tactile stimulation based on the generated data with the actual texture.

When a human places his/her hands over a source of heat, his/her hands become warm owing to thermal radiation. I propose a novel haptic display, which employs thermal radiation to display a virtual shape. A person tends to avoid a heated region at a nociceptive temperature. Using this 3 dimensional thermal control, the system displays the virtual 3-dimensional region. In this paper, I propose the laser-emission-based thermal radiation system for farther range and precise projection.

The visually impaired must obtain shape information in a tactile manner. However, existing conventional graphics are static. We prepared a more useful, dynamic tactile display; we aimed to allow the visually impaired to recognize and draw figures via tactile feedback. We developed an electrostatic force-based tactile display and performed two preliminary evaluative experiments. We measured figure recognition rates and explored how users perceived figures that were displayed in a tactile manner. We describe the results and future planned improvements.

Touch screens used as interfaces rarely give tactile feedback to users. We developed a electrostatic-force-based tactile display, however, it cannot express softness feelings on the screen. In this research, we attempted to display softness feeling by using multi-electrodes and a pressure sensor. When using our system, we observed that the user can feel change of the display area on the fingertip when his pressure toward the surface is changed.

In previous research, we proposed a method to collect accelerations in daily haptic behaviors using a ZigBee-based microcomputer. However, the method for classifying the collected data was not sufficiently implemented. We therefore propose applying collected data to classify rubbing haptic information. In this paper, we implemented a classification approach for haptic information collected by our method. We used a convolutional neural network (CNN) to classify the information. We performed a classification experiment in which the CNN classified 18 types of information, 93.2% on average. We also performed an experiment to classify rubbed objects in real-time. The CNN was able to classify five types of objects, about 67.7% on average.

The Ouija board is a game associated with involuntary motion called ideomotor action. Our goal is to clarify the conditions under which Ouija board motion occurs, comparing visual, force, and vibrotactile cues. In this paper, we demonstrated a newly developed 1-degree of freedom (DoF) Linear Rail Device, which we used to study these ideomotor actions with less friction and inertia.

We present an IoT-based children’s social behavior analysis system aimed at young children and elementary school students. Our system uses BLE-based ID logs to analyze daily social behaviors, such as how a child spent the day with his/her friends. Furthermore, we also use accelerometer logs to detect the period when the user (i.e., a child) was with friends or not, and what kind of activity (e.g., walking or staying in one place) the user was involved in. We conducted a five-day experiment with four families using our system. We also interviewed the families’ parents and compared their responses with the analyzed results to investigate the accuracy of the above detection and usability of our system. The result shows that our system can detect the period when the child was with other friends or alone, as well as the activity (s)he was involved in.

We propose an IoT-based children’s behavior analysis system for crime prevention, aimed at infants and elementary school students. The system logs children’s behavior with accelerometers and Bluetooth low energy (BLE). We conducted a preliminary experiment with a test application to examine whether BLE-based ID logs can be used to analyze daily social behaviors, such as how a child spent the day with his or her friends. The results suggest that the history of behavior with a child’s friends was acquired accurately. Furthermore, the system could detect the period when the user (that is, a child) was with friends or not, and what kind of activity (for example, walking or staying in one place) the user was involved in.

We are developing a total-internal-reflection-based tactile sensor in which the shape is reconstructed using an optical reflection. This sensor consists of silicone rubber, an image pattern, and a camera. It reconstructs the shape of the sensor surface from an image of a pattern reflected at the inner sensor surface by total internal reflection. In this study, we propose precise real-time reconstruction by employing an optimization method. Furthermore, we propose to use active patterns. Deformation of the reflection image causes reconstruction errors. By controlling the image pattern, the sensor reconstructs the surface deformation more precisely. We implement the proposed optimization and active-pattern-based reconstruction methods in a reflection-based tactile sensor, and perform reconstruction experiments using the system. A precise deformation experiment confirms the linearity and precision of the reconstruction.

In this chapter I introduce a novel precise tactile sensor, reflection-image-based tactile sensor. Today many touchscreen interfaces have become popular worldwide, however, they cannot sense forces or vibrations. For richer interfaces, precise and robust tactile sensors are required. Then we propose a reflection-image-based tactile sensor. The sensor employs deformable transparent silicone rubber and distortion of a reflection image. The construction of the sensor solves wiring issues and degradation problems. In addition, full tactile information can be acquired from the reflection images. Furthermore, active sensing enhance the robustness of the proposed sensor.

Bodily movements caused involuntarily, for example while using a Ouija board, are called ideomotor actions. Our goal is to clarify the conditions under which Ouija board motion occurs, comparing visual, force, and vibrotactile cues and using a novel pseudo haptic illusion. In this study, we used a fingertip-type tactile display to find the conditions of occurrence of ideomotor action with the Ouija board. Results showed that vibrotactile cues lead to the occurrence of Ouija board motion, and that visual cues reinforce the displacement of motion.

This book examines the state of the art in diverse areas of haptics (touch)-related research, including the psychophysics and neurophysiology of haptics, development of haptics displays and sensors, and applications to a wide variety of fields such as industry, education, therapy, medicine, and welfare for the visually impaired. It also discusses the potential of future haptics interaction, such as haptics for emotional control and remote haptics communication. The book offers a valuable resource not only for haptics and human interface researchers, but also for developers and designers at manufacturing corporations and in the entertainment industries.

This study estimated the maximum allowable system latency for haptic displays that produce tactile stimuli in response to the hand movements of users. In Experiment 1, two types of detection thresholds were estimated for the time delay of stimuli through psychophysical experiments involving 13 participants. One was a threshold for the users to notice the existence of a time delay. The other was a threshold for the users to experience changes in the perceived textures in comparison with stimuli with no time delay. The estimated thresholds were approximately 60 and 40 ms, respectively. In interviews, the participants reported that they experienced various types of subjective changes due to the time delay. In Experiment 2, the types of subjective sensations that might be altered by the time delay were investigated. The time delays were controlled based on the acceleration of the hand motions of the participants. The participants evaluated the differences in the perceived textures between the stimuli with a controlled time delay and ones with no delay. The results indicated that the participants associated the time-delayed stimuli with changes in mechanical parameters such as kinetic friction coefficient in addition to changes in the perceived roughness of the textures.

PurposeThe aim of this paper is to create a sensor that can measure the contact status with high‐resolution than ever.Design/methodology/approachThis paper proposes a new type of optical tactile sensor that can detect surface deformation with high precision by using the principle of optical lever. A tactile sensor is constructed that utilizes the resolution of a camera to the maximum by using transparent silicone rubber as a deformable mirror surface and taking advantage of the reflection image.FindingsIt has been found that the sensor can sense the deformation by the object with 1 percent error rate in simulation. In implementation of this time, the error rate results 10 percent.Research limitations/implicationsThis sensor can be used with broad applications by combining with other devices. As one of future work, the zero method will be used by using active patterns and get more accurate information.Practical implicationsUsing the transparent silicone rubbers the sensor enables very simple and low cost and high‐resolution detection method. In addition, the simplicity of our sensor results various applications. For example, the transparency makes the sensor a light pathway, so the sensor can be a contactless sensor or an interactive device.Originality/valueThe concept of a tactile sensing method is introduced which can utilize the resolution of a camera to the maximum possible extent and can detect surface deformation by using the principle of optical lever.

Touching through a screen to a displayed object has been one of a goal of human interface. Several researchers employ vibrations in order to display texture information. However no systems realize to display geometrical shapes and textures. In this research we propose a method of feeling both large bump and precise textures simultaneously through a touchscreen. Our methXod employs lateral force and high frequency direction-controlled vibration. Vibration, normal to moving direction of finger enables independent display between geometrical and texture information. The technology realizes not only geometrical shapes but also textures to be felt.

In this research, we propose an interactive display system that has a simple implementation. The system is composed of a smartphone, PC, display, and cloud service; it realizes a CAVE-like immersive system by employing simple devices. Relative location information is acquired by the user’s smartphone and a marker (or markers). Based on this information, the system renders the appropriate image in real time. In this paper, we describe the implementation and operation of the proposed system.

Stepping motors are used in many systems due to their simple driving method using open-loop control with switching devices. In the case such that a stepping motor is driven at low speed, the profile of angular displacement of the rotor becomes stepped one and rotor oscillation occurs in each step because of its switched operation. It is well known that microstep drive is one of the solutions of this problem, however currents in stator windings must be controlled precisely for execution of microstepping and consequently the drive circuit becomes complicated and expensive.The authors suggest a method to adjust the waveform of angular displacement in a step response of a stepping motor. In this method, the waveform is adjusted only by tuning the exciting sequence used for switching of the applied voltage on each winding, therefore no modification for the drive circuit is required. By adjusting the waveform appropriately, the profile of angular displacement becomes smooth even in the low-speed region.For tuning of the exciting sequence, genetic algorithm is used in the present work. In this algorithm, the step response of the motor is modeled as an individual of artificial life which has a genotype constructed by coding the exciting sequence. Each individual is evaluated by its fitness of the waveform to desirable one. Applying this method to the tuning process of the exciting sequence, it is shown that the waveform of angular displacement can be adjusted to a ramp function. Moreover, the driving characteristic in lowspeed region is improved by using the tuned exciting sequence.

Displaying haptic and tactile information on a touchscreen is one of the key technologies for human interfaces. In this paper we propose a method that allows the user to simultaneously feel both large bump and small textures through a screen. Our method employs lateral force and direction-controlled mechanical vibration (around 0-400 Hz). The technology allows not only geometrical shapes but also textures to be felt. Our experiments revealed that with our proposed method almost all people can simultaneously detect geometry and texture information on a touchscreen. In addition, providing adequate direction for the vibration enhances the feelings of softness.

Touching through a screen to a displayed object has been one of a goal of human interface. Several researchers employ vibrations in order to display texture information. However no systems realize to display geometrical shapes and textures. In this research we propose a method that allows the user to feel both large bump and precise textures simultaneously through a touchscreen. Our method employs lateral force and high-frequency (around 1-10kHz) direction-controlled vibration. Vibration, normal to moving direction of finger enables independent display between geometrical and texture information. The technology allows not only geometrical shapes but also textures to be felt.

In this paper we discuss about the tactile information required for touchscreen interfaces, and propose a lateral-force-based 2.5-dimensional haptic display. The use of a lateral-force-based display enabled virtual bump sensations to be presented. Recently touchscreen interfaces have become popular worldwide. However, few touchscreens provide tactile feedback. Little hardware is commercialized for such kind of touchscreen. From our consideration, “press,” “guide,” and “sweep” movement are essential information for touchscreens. However, these devices have some operational disadvantages of these information. We intend to cope with these disadvantages by introducing the new idea of lateral-force-based display. We developed an experimental prototype of lateral-force-based display, investigated 2.5-dimensional sensations, realized a part of these essential information, and confirmed the requirement of displayed force control according to spatial wavelength. Furthermore we propose measuring method of spatial wavelengths employing multi-resolution analysis based on Haar wavelet transformation.

In recent years, many tactile sensors have been developed for the practical use in robotics and to meet the increasing demand for intuitive interfaces. However, the implementation of conventional tactile sensors is very complex. We develop a simple total-internal-reflection based tactile sensor that measures the shape of the sensor surface from a reflection image of the surface and evaluate its performance. We previously proposed a reconstruction method which solves geometric optical constraints of the sensor surface by optimization, however this method could not meet real-time and accurate reconstruction simultaneously. To solve this problem, in this paper, we propose a new reconstruction method based on the previously proposed one. By reconstruction experiments with simulated reflection images, we found that the proposed method could perform real-time and accurate reconstruction and was applicable to various sensor shapes and robust to feature tracking error and the presence of contact areas on the sensor surface without total-internal-reflection property. Then, we implemented the proposed method on the actual sensor and confirmed that the sensor could perform real-time reconstruction.

Recent years with the spread of tactile interfaces, there are many types of tactile displays. Many types of these conventional devices are displaying the physical information of the environment, such as the object shapes or forces. In other hand recent devices displays not the physics itself but the information of cutaneous sensation. However these latter devices are not multi purposed but very much specialized devices. Each expression of the object requires each different device. Here we propose multi purpose oriented display using a fluid which is deformable and elasticity changeable. With this device we consider the new type of display which has expression of various type of elasticity and the possibility of controllable deformation. In this paper we propose tactile display using dilatant fluid as having dynamic elasticity and deformable material.

Today there are many tactile sensors in the world. Though there is few sensor whose characteristics are similar to cutaneous sensation of human. If we want to measure the tactile information of human we have to use human-like tactile sensor. Here we have developed a reflection-type tactile sensor by using imaging device. This sensor employs a simple total reflection characteristic, so it has many degrees of freedom of selecting sensing units, and designing layer structures. This paper describes the design of the sensing unit and the structure of layers which has similar characteristics of human. First we compare the temporal frequency of the proposed sensor and human skin. Second we estimate the required spatial density of sensing units by simulation. Then we compare the total ability of proposed reflection-type sensor and cutaneous sensation of human.

We propose a new framework for a self-propelled flexible cable in which the freedom of lateral motion with sliding movements is increased on the basis of simple shape information.We developed a large-scale prototype of the flexible cable that has a ciliary drive mechanism and precise shape sensors to investigate our concept.We developed a kinetic model for the prototype by employing the nonlinear driving force model and the lateral friction model for representing slippages. Further, we proposed a sliding motion control method that focus on the shape and length of the straight element. We applied the method to control the running direction. The experimental results and dynamic simulations demonstrated the effectiveness of sliding motion for controlling the running direction.

In the search and rescue situation at the disaster area, the searching task should be conducted by robots in order to avoid the second disaster. We study crawler robots that can traverse rough terrains and are used in such search operations. This paper describes the designing of an online simulation environment using which we can develop control algorithms for crawler robots, especially for the robot named ldquoKenaf.rdquo We use USARSim that can simulate three-dimensional space. By employing realtime simulation, we connect a real robot controller and the simulator directly and realize online simulation using the real robot controller. The tests show that the created simulation system can be used for the development of control algorithms.

IRS Soryu is rescue robot which used for victim search in disaster area. We aim at development of display method for wide view angle and high definition images for controlling the rescue robots and searching for victims. In our study, we developed small size multi camera system and displayed a wide view angle and high definition image. However, it is too hard for an operator to recognize the robot and environment intuitively. We need to develop a display method of these multi camera images for intuitive recognition. In this paper, we develop the on-line simulation system for the verification of multi camera based wide field of view display. This system has some requirements that; a. Simulation of IRS Soryu dynamics, b. Simulation of multi camera system, c. Flexibility of camera setting. We developed such simulator based on USARSim. Using the simulator, we examined some experiments for the verification of of the display methods.

Tactile display is a technology that gives an artificial sense of touch to operators of information terminals or master-slave systems. The generation of tactile stimuli in response to the hand movements of the operators is associated with active touch and is considered to be one of the effective display methods, however which inevitably causes delayed tactile feedbacks from tactile displays. The knowledge of the detection threshold of system latency between the hand movements and the stimuli is helpful in designing the tactile displays. In this study, the identification of the thresholds through psychophysical experiments of 13 participants revealed two types of thresholds. One was the time-delay at which the participants observed the existence of latency. The other was the minimal time-delay that could affect the subjective feelings of the operators while they were not conscious of the latency. The means of the thresholds were 41 ms and 59 ms, respectively. The participants reported that the time-delay stimuli caused various changes in their subjective feelings. The empirical results suggest that the two types of thresholds depend on different sensory processes. This paper also proposes a design policy for tactile display systems in terms of system latency.

Considering tactile sensors there are two ways to acquire object information. These are spatial sensing with two dimensional devices and fast sensing with simple devices. Because the reflection-type tactile sensor uses a reflection image, both methods can be employed. Though there exist some dynamic characteristics in these two ways. In this study, we first validate the hysteresis of the reflection-type tactile sensor. The results show the sensor can evaluate displacement less than 2 mm. Then we propose a novel interface called "fibratus tactile sensor." Secondly we construct a fast sensing device using reflection image and a combination of light emitting diodes (LEDs) and photodiodes (PDs), and validate the sensor's reactivity. It can distinguish 300 ms interval between two signals. Moreover the correlation between the standard deviations of the acquired outputs from the sensor and the centerline average roughness is 0.90.

Among several tactile sensors in use currently, none can evaluate the sense of gentle touch. We have developed a fibratus tactile sensor that utilizes the property of reflection. This sensor enables to evaluate the sense of gentle touch. We propose a new interface device that employs this fibratus tactile sensor.