Hideyuki Sawada

Hideyuki Sawada
Waseda University | Sōdai · Department of Applied Physics

Ph.D.

About

182
Publications
15,019
Reads
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1,186
Citations
Additional affiliations
April 1999 - present
Kagawa University
Position
  • Professor (Full)

Publications

Publications (182)
Article
Full-text available
This study aims to investigate electrical effects in self-propelled oil droplets and analyze the motion caused by electrical interactions between two droplets. We examine the motion of self-propelled oil droplets in terms of electrical effects; no similar analyses have been reported to date. When an oleic acid droplet is introduced into a surfactan...
Article
Full-text available
Nowadays, improving the traffic safety of visually impaired people is a topic of widespread concern. To help avoid the risks and hazards of road traffic in their daily life, we propose a wearable device using object detection techniques and a novel tactile display made from shape-memory alloy (SMA) actuators. After detecting obstacles in real-time,...
Article
We here introduce three types of self-actuating and nonelectronic machines using chemical reactions and physicochemical transformations. Our strategy is to develop completely artificial and autonomous machines that do not rely on electronic components. We herein demonstrate Belousov-Zhabotinsky gel machines, active droplet machines, and paper machi...
Article
Full-text available
While Reinforcement Learning (RL) is one of the strongest unsupervised learning algorithms, it often faces difficulties dealing with complex environments. These difficulties correlate with the curse of dimensionality in which an excessively large number of states causes the process of RL prohibitively difficult. Hierarchical Reinforcement Learning...
Article
In the field of 4‐D space visualization, the information of 4‐D space is obtained by projecting 4‐D data onto 3‐D space. Most of the previous research has been aimed at the recognition of 4‐D space, whereas the target of the recognition has been limited to the geometrical information of 4‐D objects in 4‐D space or static spatial information without...
Article
Self-propelled oil droplets locomote by internal Marangoni convection, and the phenomena have been widely investigated so far. By attaching an exoskeleton frame to an oil droplet dropped into aqueous solution, Marangoni convection is generated due to the concentration distribution of surfactant at the oil droplet interface, in accordance with the d...
Article
Surface tension gradient in droplet generates marangoni convection from the place with higher surface tension to the place with lower surface tension. In this study, we try to generate and control the marangoni convection in the droplet by using volatile solution. We observe Marangoni convection using the PIV method, and discuss the formation princ...
Article
In this study, we focus on the chargeability of self-propelled oil droplets, and attempt to control their behavior. Multiple oleic acid oil droplets show probabilistic motions such as follow-up motion, translational motion, and repulsive motion by the interaction between the oil droplets and the surfactant solution. To control the behavior of multi...
Article
We study the motion control of a self-propelled oil droplet dropped into aqueous solution by using a rigid frame. It is well known that an oil droplet with fatty acid anhydride moves in random directions in aqueous solution. Although we have discovered that the moving direction could be controlled using a rigid boomerang-shaped frame, the mechanism...
Article
“Tears of wine” is a physical phenomenon that appears due to the result of a liquid flow along the glass surface against the gravity. In this study, we try to visualize the convection inside droplets in "tears of wine" by using the particle image velocimetry (PIV) method. We also examine the difference of convection flow which occurs when heat is a...
Article
Full-text available
Advances in printing technology and design software have enabled the rapid and convenient replication of entities. Herein, a method that provides motility to a paper through inkjet printing and that makes a paper self‐fold along printed lines is presented. A sequence of self‐folding is successfully programmed by modifying the dynamics of self‐foldi...
Article
Tactile feedback is a key sensory channel that contributes to our ability to perform precise manipulations. In this regard, sensor skin provides robots with the sense of touch making them increasingly capable of dexterous object manipulation. However, in applications like teleoperation, the complex sensory input of an infinite number of different t...
Chapter
When humans get tactile sensation, we touch an object with the skin and the stimuli are transmitted to the brain. The effect of the skin in tactile perception however has not been clarified yet, and sensors considering the skin functions are not introduced. In this research, we investigate the information processing performed by the skin against ph...
Article
Full-text available
Self-folding technologies have been studied by many researchers for applications to various engineering fields. Most of the self-folding methods that use the physical properties of materials require complex preparation, and usually take time to complete. In order to solve these problems, we focus on the elasticity of a material, and propose a model...
Article
We have developed a wheel robot which locally transforms its diameter to improve mobility of a wheel on uneven terrain. Our wheel robot locomotes on a flat road with high mobility of a wheel and on rough terrains by changing its diameters. We developed a variable diameter wheel as a prototype of the wheel robot and investigated its availability. In...
Article
In this research, we focus on a self-propelled phenomenon of an oil droplet due to surface activation reaction. It is known that the behavior of a self-propelled oil droplet varies depending on its shape. When an oil droplet is spherical shape, the droplet shows stochastic behavior such as curvilinear motion and direction change, and when the oil d...
Poster
We focused on the high elasticity of elastomer, and proposed a model for forming a three-dimensional structure using its characteristics. Furthermore, by exploiting elastomer as a dielectric elastomer actuator (DEA), we developed prototypes of a self-assembled actuator which can be driven by voltage application. We attempted several experiments to...
Article
Full-text available
This paper introduces a novel directional control method of self-propelled oil droplets. Oil droplets locomote spontaneously with surfactant action. This self-propulsion is caused by Marangoni convection within the oil droplet due to differences in the surfactant concentration at the droplet surface. Recent studies have reported that self-propelled...
Article
Full-text available
This paper presents a new kind of climbing robots called EJBot, which has not been restricted to climb certain surface materials or terrains. EJBot is inspired by propeller-based aviation systems, however, its adhesion principle is opposite to flight concept. Thanks to the hybrid actuation system embedded in this robot which gives a good and stable...
Conference Paper
There are many studies on neural networks to control autonomous robots operating in real world environments. The well-trained neural networks give good solutions in many cases. However, we cannot understand the reason why the solutions are appropriate because the neural networks do not give any explanations just like black box does not. This incomp...
Article
This paper presents a novel method for humanoid robots to recover their attitude from falling-down states to the standing state. The robot estimates its attitude using the ground-contact information sensed by the pressure sensors attached to its whole body and the joint angle data. According to the estimated attitude, the robot searches an action s...
Article
Full-text available
In human speech, the timing function is important for determining its duration, stress and rhythm; however, little attention has been paid to these issues when building a speech synthesis system. In the human brain, the cerebellum plays a key role in the coordination, precision and timing of motor responses. We have developed a talking robot, which...
Article
Purpose of Review: This article describes the classification, diagnosis, examination, mechanism, prevention, and treatment of diabetic neuropathy. This review details a method for examining distal symmetric polyneuropathy (DSPN), which is the most frequent type of diabetic neuropathy. Recent Findings: We also discuss a new tactile test method that...
Article
Full-text available
To investigate the efficacy of the finger method using a new microvibration sensation measurement device in the evaluation of diabetic peripheral neuropathy (DPN). A cross-sectional study of 52 type 2 diabetic outpatients was performed. Patients were evaluated for DPN using American Diabetes Association (ADA) criteria, Michigan Neuropathy Screening...
Article
Full-text available
The authors are developing a talking robot based on the physical model of human vocal organs in order to reproduce human speech mechanically. This study focuses on developing a real-time interface to control and visualize talking behavior. The talking robot has been trained using a self-organizing map (SOM) to reproduce human sounds; however, due t...
Article
Diabetes mellitus is a group of metabolic diseases that cause high blood sugar due to functional problems with the pancreas or metabolism. Diabetic patients have few subjective symptoms and may experience decreased sensation without being aware of it. The commonly performed tests for sensory disorders are qualitative in nature. The authors pay atte...
Article
Diabetes mellitus is a group of metabolic diseases that cause high blood sugar due to functional problems with the pancreas or metabolism. Diabetic patients have few subjective symptoms and may experience decreased sensation without being aware of it. The commonly performed tests for sensory disorders are qualitative in nature. The authors pay atte...
Article
Full-text available
Purpose: Endoscope-assisted surgery has widely been adopted as a basic surgical procedure, with various training systems using virtual reality developed for this procedure. In the present study, a basic training system comprising virtual reality for the removal of submandibular glands under endoscope assistance was developed. The efficacy of the t...
Conference Paper
Full-text available
This study compares several acoustic features for developing an automatic vowel sequence reproduction system for a talking robot, which is a mechanical vocalization system modeling the human articulatory system. Matlab-based control system is used to analyze a recorded sound and drives the articulatory motors of the talking robot. A novel method ba...
Conference Paper
In the recognition of an object situated in front of us, we firstly watch it and then try to touch it to feel the tactile and haptic sensation to be perceived by our hands. Various virtual reality and augmented reality systems have been introduced with the growing computational powers, however visual and auditory information related with a virtual...
Chapter
A compact device for the presentation of tactile sensation is introduced in this chapter. By employing shape-memory alloy (SMA) wires, a novel tactile information transmission device is developed for displaying various tactile sensations. A tactile actuator consists of a thin SMA wire with the diameter of 50 μm, and generates micro-vibrations with...
Article
Full-text available
This paper describes an automatic vowel sequence reproduction system for a talking robot built to reproduce the human voice based on the working behavior of the human articulatory system. A sound analysis system is developed to record a sentence spoken by a human (mainly vowel sequences in the Japanese language) and to then analyze that sentence to...
Article
A novel micro-vibration actuator using a shape-memory alloy (SMA) for the presentation of various tactile sensations to human skin will be introduced in this paper. A tactile actuator consists of a thin SMA wire with the diameter of 50μm, and generates micro-vibrations with various frequencies and amplitudes synchronizing with a driving pulse signa...
Article
Various vocal sounds are generated by the complex articulations of human vocal organs under the feedback control mechanisms using the auditory system. By reconstructing a human vocal system mechanically, the authors have developed a talking robot based on the physical models of vocal organs. The robotic system consists of motor-controlled vocal org...
Article
Information presentation through tactile sensation is actively studied these days, and various tactile displays using different actuators have been introduced by many researchers so far. It is, however, still hard to assume that information presentation through tactile medium would be suitably applied to products for general public. The authors hav...
Article
The author is developing a talking robot by reconstructing a human vocal system mechanically based on the physical model of human vocal organs. The robotic system consists of motor-controlled vocal organs such as vocal cords, a vocal tract and a nasal cavity to generate a natural voice imitating a human vocalization. By applying the technique of th...
Conference Paper
An innovative tactile pad that presents various tactile sensations synchronizing with moving pictures is presented in this paper. To display tactile/touch sensations from a pad, a tactile display panel is designed by employing 10 micro-vibration actuators that provide tactile-stimulation sources using shape memory alloy wires. With the employment o...
Article
An automatic speech recognition system is one of the popular research problems. There are many research groups working in this field for different language including Japanese. Japanese vowel recognition is one of important parts in the Japanese speech recognition system. The vowel classification system with the Mamdani fuzzy inference system was de...
Article
In this paper, an innovative vision based tactile display system is presented. Using common web camera to get visual information, the developed system captures and recognizes the shape of an object by proposed method which combines basic algorithm of the active contour and Harris corner detection. In order to let people sense the shape of the captu...
Conference Paper
Humans communicate with each other by using not only verbal media but also the five senses such as vision, audition, olfaction and tactile sensations. Various devices and systems have been introduced for supporting human communication, and most of them are based on visual and auditory media. For presenting tactile sensations, some tactile actuators...
Conference Paper
In the vocal communication, we employ not only the speech and auditory ability but also the body actions such as gestures and gaze to react to the speech. For example, a human nods to a speaker for an agreement, and makes eye contact during the conversation. The purpose of this study is to realize a human-like auditory system using a robotic arm, w...
Conference Paper
The authors have developed a talking robot by reconstructing a human vocal system mechanically based on the physical model of human vocal organs. The robotic system consists of motor-controlled vocal organs such as vocal cords, a vocal tract and a nasal cavity to generate a natural voice imitating a human vocalization. By applying the technique of...
Conference Paper
Diabetes mellitus is a group of metabolic diseases which causes high blood sugar to a person, due to the functional problems of the pancreas or the metabolism. For a person with diabetes, glucose would not be used properly in the metabolic system, and cause health problems, such as polyphagia, polyuria and polydipsia, since glucose is the main sour...
Article
In this study, a new Braille display is constructed based on the vibration of a Shape Memory Alloy (SMA) wire. To present Braille information, a vibration actuator is used instead of conventional Braille dots. According to the temperature-dependent characteristic shrinkage and the vest ration to the initial length of an SMA wire, a vibration actuat...
Conference Paper
A novel portable Braille display for mobile use is constructed by employing the micro-vibrations generated by small Shape Memory Alloy (SMA) wires. According to the characteristics of the shrinkage and expansion of a SMA wire formed into a diameter with 50 micro-meters, a vibration actuator which can be driven by several to 300 hertz pulse signals...
Article
In the research of augmented reality, many experimental systems have been introduced so far by presenting CG objects into a real environment with visual and auditory information, so that a user would interact with the CG objects and the environment. To present higher reality, not only visual and auditory information but also tactile and other stimu...
Conference Paper
Mangosteen export generates large revenue; however, translucent mangosteens, which contain undesirable internal condition, result in the shipment rejection and decrease the reliability of the export. This research investigates a novel non-destructive classification approach based on acoustic frequency response to detect mangosteens containing trans...
Article
A talking and singing robot which adaptively learns the vocalization skill by an auditory feedback learning is being developed. The fundamental frequency and the spectrum envelope determine the principal characteristics of a sound. The former is the characteristics of a source sound generated by a vibrating object, and the latter is operated by the...
Conference Paper
In the research field of augmented reality, many experimental systems have been introduced so far to provide natural interactions with a virtual character and a surrounded environment. To introduce a high level interaction, not only visual and auditory information but also other human sensations such as tactile sensations and somatosensory informat...
Article
A touch screen is an electronic visual display that can detect the presence and location of a touch within the display area surface. The term generally refers to stressing the display area of the device with a finger of a hand. A common type of touch screen only receives a user's finger stress as an input. However, the user himself is not able to f...
Conference Paper
Full-text available
Feature extraction is a crucial step for many systems of face detection and facial expression recognition. In this paper, we present edge-based feature extraction for recognizing six different expressions, which are angry, fear, happy, neutral, sadness and surprise. Edge detection is performed by using Gabor wavelet and convolution filters. In this...
Article
Full-text available
Facial expression recognition has recently become an important research area, and many efforts have been made in facial feature extraction and its classification to improve face recognition systems. Most researchers adopt a posed facial expression database in their experiments, but in a real-life situation the facial expressions may not be very obv...