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374
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Introduction
Official repository of my publications is the following link.
I uploaded PDF files as much as possible.
http://t2r2.star.titech.ac.jp/cgi-bin/researcherpublicationlist.cgi?q_researcher_content_number=CTT100514633&alldisp=1&lv=en
Additional affiliations
April 2014 - March 2015
Publications
Publications (374)
The McKibben muscle, widely employed in antagonistic drive robots, exhibits approximately 20% contraction under pneumatic pressure but lacks crucial passive extensibility. Previous attempts to achieve passive extensibility resulted in reduced overall contraction ratios due to the series connection of elongation and contraction sections. This study...
The McKibben muscle can produce a high force-to-mass ratio, beneficial for various applications in the soft mechatronics field. The thin McKibben muscle, which has a small diameter, has the advantage of a high force-to-mass ratio and sufficient flexibility for use in a bent state. This flexibility permits the realization of flexible mechatronics. H...
Soft robotics, including soft grippers and manipulators, are increasingly required to function more adaptively and securely in unknown environments. However, conventional soft pneumatic grippers often grasp and hold objects via the active bending of multiple fingers, making it challenging to grip and hold, for example, spiny objects safely because...
Hydraulic artificial muscles offer superior performance compared to most pneumatic artificial muscles, but their suitability in multi-DOF robotics remains unverified. We fabricated a 7-DOF power soft robot spanning over 1.5 m using 29 McKibben hydraulic artificial muscles. We analyzed the proposed robot's workspace, payload capacity, and compliance...
There is a need for technology to investigate the large space beyond a narrow hole. An example is the exploration of the Main Stream Isolation Valve (MSIV) room at the Fukushima Daiichi Nuclear Power Plant. The authors designed and fabricated a prototype long articulated arm, LIBRA-I, for this exploration. The design requirements were that the robo...
The Fukushima power station in Japan was affected by a major earthquake and tsunami in March 2011, inspecting the primary containment vessel remains difficult due to high radioactivity. Long-reach robot arms are useful in inspecting such hazardous environments, and a coupled tendon-driven mechanism enables realizing a long, light-weight, and thin m...
The exploration and inspection of narrow spaces in nuclear facilities require the use of long-reach manipulators. Coupled tendon-driven manipulators can realize lightweight and slender arms by positioning actuators, such as motors, at the base. Currently, we are developing a coupled tendon-driven super long-reach articulated arm, which we name “Sup...
We experimentally measure a continuous strain distribution using low-coherence Brillouin optical correlation-domain reflectometry, which suppresses the noise caused by the sidelobes of a beat spectrum of conventional sinusoidal modulation.
Gripping slippery and flexible tissues during minimal invasive surgery (MIS) is often challenging using a conventional tissue gripper. A force grip has to compensate for the low friction coefficient between the gripper’s jaws and the tissue surface. This study focuses on the development of a suction gripper. This device applies a pressure differenc...
In order to improve spatial awareness for future investigations of reactor No. 2 at the Fukushima nuclear power plant, it is necessary first to acquire the environment model through reconstruction. To gather images for this task, we have developed a flexible, compact, and lightweight manipulator called the Bundled Wire Drive robot. However, due to...
Pneumatic artificial muscles have some advantages. Especially, the flexibility of artificial muscles contributes to compose novel mechanisms. Authors succeeded in manufacturing novel soft mechanisms that are composed of only woven artificial muscles and strings. We called this mechanism active textile. The structure is uniformed with woven artifici...
In food factories, serving is still done manually by people in many cases. To solve the problem of quantitative serving, which is one of the challenges in robot operation, we developed a Chobit Hand that can precisely grasp only one strand of spaghetti. In this paper, we simulated whether installing the Chobit Hand on a multihead weigher would incr...
It is necessary to explore the bottom of the RPV in order to accelerate the decommissioning of the Fukushima Daiichi Nuclear Power Plant. A coupled tendon-driven articulated robot arm, Super Dragon, has been developed to deploy the investigation equipment into the containment vessel. In this paper, we developed an extended Super Dragon with a lengt...
The purpose of this research is to develop an elephant trunk shaped power soft robotic arm with both high power and flexibility. Our proposed arm consists of three elements: hydraulic artificial muscles to drive the arm, a compressive stress support component reinforced with fabric, and a gripper reinforced with knit. In this paper, We fabricated p...
Being soft imparts a functionality of body compliance, thereby enhancing the range of actuation and adaptability to unstructured environments. The present study focuses on the development of a multi-balloon dielectric elastomer actuator to provide a traveling-wave for the linear transportation of objects. The actuator consists of an electrode-patte...
Tendon-driven mechanism enables to realize a long-reach robot arm to inspect in industrial plants. However, a large elastic elongation of tendons due to gravitational joint torque makes joint control unstable. In this paper, we proposed a planning method to search for a path that includes only stable postures. The stability of the joint angle was f...
In this study, we investigate the applicability of the plastic parts made by FDM 3D printer to a trocoid gear reducer, which is expected to reduce the weight. A trochoidal gear reducer with a reduction ratio of 30 was developed. The part was developed using a resin material with excellent mechanical strength, nylon resin reinforced with carbon shor...
The scope of application of 3D printing has been expanding due to the diversification of materials that can be used. However, the design of parts manufactured by 3D printing depends on the individual know-how, which raises the threshold for the introduction of 3D printing. In this study, we propose two methods for applying 3D printing to industry:...
An ionic polymer metal composite (IPMC) is a polymer actuator that bends when a voltage is applied. In this paper, we proposed a method for producing a three-dimensional IPMC by three-dimensionally molding an ion exchange resin using a water-soluble support material and plating it with gold. The proposed method has made it possible to manufacture I...
Hydraulic actuators have a much higher power density than their electromagnetic counterparts. However, traditional hydraulic systems are powered using a centralized hydraulic unit that operates continuously regardless of the conditions of the actuators. This results in low power efficiency. Electrohydrostatic actuators, on the other hand, combine a...
In the field of food processing and production processes, serving is still done manually by people in many cases. To solve the problem of quantitative serving, which is one of the challenges of robotic operations, we have developed an end-effector that can grip only one spaghetti. In this paper, we propose a method of attaching several small finger...
The demand for collaborative robots is expected to increase in the future due to their high adapt-ability. However, most of collaborative robots available in the market are driven by a combination of electromagnetic motors and reduction gears, and thus the weight of the arm itself tends to become larger in order to increase its payload. This study...
We proposed a long-reach lightweight articulated arm ”Hiryu-III” using weight-compensation with thrusters and a wire-pulley system. This robot uses a wire-pulley system to keep the thruster horizontally, however the elastic deformation of the plastic tensioner causes insufficient rigidity of the pitch axis. We changed the fastening method between t...
Self-excited electrostatic actuators are suitable for small robots because they have a simple structure, are driven by DC voltage, and the force density increases with decreasing size. We have combined this actuator with a PLZT element, which has the property of generating a high voltage when irradiated with ultraviolet light, to fabricate a wirele...
In recent years, the use of 3D printed plastic parts has been attracting attention. However, due to their inferior dimension accuracy, stiffness and strength, there are few examples of using them as structural parts for robots that are subjected to loads. In this study, we developed a quadruped robot, TITAN-E1, in order to verify the applicability...
Textile is soft, adaptable to shape, elastic, and lighter than metal. Taking advantage of these characteristics, textile is used as a material for soft robots. The authors thought that by using a cloth made of high-strength fibers, it would be possible to create a robot that takes advantage of its strength and durability in addition to its flexibil...
We proposed a model in which three small cranes are used to form a three-dimensional truss structure to perform construction work in a coordinated manner. In this model, the workspace and payload depend only on the strength of the structure because the structure does not tip over as in conventional cranes and excavators. This makes it possible to l...
One of the purposes of exploration and inspection of nuclear facilities is to understand the distribution of nuclear materials in reactor. This is because if the elements can be characterized on-site, decommissioning can be carried out efficiently. Therefore, it is necessary to attach a sensor to the tip of the long manipulator to perform on-site e...
This paper describes a soft robot that aims to move forward in an unknown space as it recognizes and adapts to the spatial shape of the environment. It was previously reported that soft tensegrity and Recurrent Neural Network (RNN) can be used to realize tensegrity structure shape recognition. In this study, a tensegrity robot was designed to activ...
Soft actuators made of flexible materials, such as rubber and polymers, have possibilities that conventional solid actuators do not have, such as no unnecessary force is applied and the object is not damaged, and the flexible mechanism allows quick operation. In this paper, we describe a transport mechanism that we believe can be achieved by using...
To date, many robots have been researched and developed for the purpose of investigation and support at disaster sites, and quadruped robots are expected to play an important role because of their superiority in traversing rough terrain and stability. At present, there are many quadruped robots driven by electromagnetic actuators for investigation...
Ionic Polymer Metal Composite (IPMC) is planar and it is necessary to apply AC voltage to both sides of the IPMC in order to drive it repeatedly. Since the generated force is small, the interference caused by the wiring, critically limits the motion. In this study, I consider the following two issues separately in order to drive an independent IPMC...
Ionic Polymer Metal Composite (IPMC) has the features of high responsiveness, and can be driven in water by low voltage. Generally, IPMC actuators are fabricated using Nafion sheets, which are an ion-exchange resin, and are driven by bending a flat structure. However, in order to realize more complex motion and shape, it is necessary to fabricate 3...
Soft robotic is a rapidly developing field exploiting biomimetic design principles, novel actuation concepts, and manufacturing techniques. The present study focuses on the development of a spiral pneumatic rubber actuator which can transport objects placed on the surface of actuator. The actuator consists of multiple air chambers and provides sequ...
On March 11, 2011, a serious accident occurred at the Fukushima Daiichi Nuclear Power Plant of Tokyo Electric Power Company Holdings, Inc. due to the Great East Japan Earthquake and tsunami. Currently, nitrogen gas is used to fill the reactor containment vessel, pressure vessel, and plant piping to prevent a hydrogen explosion. Gas leak detection t...
Hydraulics is a promising technology for robots. However, traditional hydraulic infrastructures are often large and power-inefficient, with large power sources that hinder mobility. In contrast, electro-hydrostatic actuators are relatively power efficient, but their cost and weight can be excessive in systems with a higher number of degrees of free...
Artificial multiarticular musculoskeletal systems consisting of serially connected links driven by monoarticular and multiarticular muscles, which are often inspired by vertebrates, enable robots to elicit dynamic, elegant, and flexible movements. However, serial links driven by multiarticular muscles can cause unstable motion (e.g., buckling). The...
There are many studies on the antagonistic actuation of pneumatic artificial muscles; however, hydraulic artificial muscles have been rarely studied. The purpose of this study is to compare the characteristics of the antagonistic actuation of hydraulic muscles under different servovalve configurations. A dual-servovalve configuration can independen...
This letter introduces a research project as invited research of Science of Soft Robots from 2019–2020. The primary purpose of this research is to investigate the mechanical durability of fabrics subjected to repeated bending, as when used as a structural part of a soft robot. The fabric is then applied to a soft robot, a gripper for food handling....
The neck of a giraffe has excellent characteristics that can serve as a good alternative for designing a large robotic mechanism. For example, the neck can rapidly move when performing necking, a motion where the giraffes strike each other’s necks. Furthermore, the neck of a giraffe helps prevent impacts and adapts to the shape and hardness of the...
The primary role of a robot exploring an unknown space is to investigate the state and the spatial shape of the environment. We have designed a soft robot that aims to move forward in an unknown space as it recognizes and adapts to the spatial shape of the environment. We previously reported that soft tensegrity and recurrent neural network can be...
We have proposed to apply a long-reach articulated robot arm for the internal investigation of the Fukushima Daiichi Nuclear Power Plants. This report describes the development of the articulated robot arm. To search at the bottom of the Reactor Pressure Vessel (RPV), we need to deliver measurement devices five meters above the X-6 penetration in t...
We proposed a long-reach lightweight articulated arm "Hiryu-III" using weight-compensation with thrusters and a wire-pulley system. The robot developed in this study equipped with two thrusters for weight-compensation and pitch axis motion control in each joint. The previous study, Hiryu-II, had the disadvantage of low rigidity around the roll axis...
Legged robots have an advantage for moving on rough terrain. Especially, quadruped robots have high posture stability. However, actuators of many legged robots are actuated by an electromagnetic motor and a speed reducer, and are vulnerable to impact. On the other hand, hydraulic actuators have a simple structure and a small number of parts, thus t...
Needs of new materials that can be used a mechanical parts for industrial robots are increasing. 3D printers can be a very effective solution to this problem, as they can be used with a wide variety of materials, from metals to super engineering plastics, and can produce complicated 3-dimensional parts at low cost. However, when 3D printers are use...
We have developed a rugged terrain mobile robot equipped with an elastic telescopic arm for the purpose of improving moving performance on rugged terrain. The problem of the elastic telescopic arm is the low tension transfer efficiency of the passive pulley. In order to investigate the tension transfer efficiency, an experiment was conducted to obt...
An ionic polymer metal composite (IPMC) actuator is one of the lightweight and flexible polymer actuators. A method of three-dimensionally forming IPMC (PF-IPMC) by using paper or cloth has been proposed. We have proposed a method of forming a three-dimensional ion exchange resin by forming the ion exchange resin using water-soluble paper and then...
Today, the demand for industrial robots continues to grow. In order for industrial robots to make further progress, they need to reduce costs. One way to achieve this is to adapt new materials to robots in order to reduce power consumption by reducing weight. In order to realize the use of resin materials for FDM 3D printers as these new materials,...
The leg configurations of multi-legged robots are classified into mammal and insect types based on the arrangement of the degrees of freedom. However, few studies have quantitatively compared the two leg configurations. We compared the power consumption of static walking while changing body height and foot trajectory. The results of the analysis sh...
In recent years, powered exoskeletons are getting more and more attention. Most of the existing powered exoskeletons use electric motors as actuators which usually make them bulky and be sensitive to impact and vibration. To solve these problems, we tried to use Hydraulic artificial muscle (HAM), an innovative McKibben type artificial muscle, as an...
Decommissioning of Fukushima Daiichi Nuclear Power Station is a national urgent problem in Japan. To analyze and characterize the fuel debris distributed in Reactor Pressure Vessel (RPV), the optical fiber LIBS analysis method can be a promising solution. To deploy the LIBS sensor to the RPV, I have developed (1) a lightweight telescopic boom that...
We developed the hydraulic quadruped robot, “Tough Runner”, for the purpose of opening up the possibilities of hydraulic quadruped robots. In this paper, we demonstrated that this robot is able to accomplish simple missions, specifically reaching a target from an arbitrary position by being combined with the Global Navigation Satellite System (GNSS...
This paper describes an investigation of the position accuracy of a long-reach coupled tendon-driven robot arm. An operational test of the arm was conducted in a full-scale field. Tip positions estimated using joint angles were compared with the tip position measured by the laser scanner. As a result, the tip position error in the yaw bending postu...
Most of the robot arms currently in use consist of an electromagnetic motor and a reduction gear. However, they are not suitable for use in environments such as construction sites. In order to solve this problem, a compact and high-torque hydraulic robot arm was developed in our laboratory. In this study, we aim to apply this robot arm to collabora...
Small robots are attracting attention for exploring narrow/confined spaces that humans cannot enter. Among various small robots, bristle-bots have been studied for microrobots because of their simple structures. Although various actuators such as electromagnetic motors and piezoelectric actuators have been used for actuators of bristle-bots, this r...
Soft materials, unlike hard materials such as metals, have properties such as flexibility, adaptability, and high compliance. Textile is one of the soft materials that we are familiar with, and is used to make clothes, bags, towels, and masks. High-strength textiles which are composed of high-strength fibers are expected to be used as materials for...
Robotic manipulators using thrusters for weight compensation are an active research topic due to their potential to exceed the limits of maximum length. Due to the constraints of the cubic-square law, the structure of large manipulators must be flexible, making hardware development a very difficult issue. This paper focuses on overcoming these prob...
Ionic-Polymer Metal Composites (IPMC), one of the representative polymer actuators, has a structure consisting of an ion-exchange membrane and metal electrodes joined together. Conventionally developed IPMC robots are usually made by cutting and pasting sheets of IPMC, which requires an assembly process and is inefficient in realizing complex struc...
The mechanisms of the current robotics are completely different from the muscle driving mechanisms of humans or animals. The 7-DOF power soft robot arm driven by hydraulic artificial muscles developed in this study can potentially achieve the coexistence of strength and softness while having motion characteristics close to those of humans. This rob...
Necks of giraffes have excellent characteristics as a robot mechanism. In order to gather knowledge to realize power-soft robots that have both powerfulness and flexibility, we focus on necks of giraffes from the point of view of robotics We develop a half sized musculoskeletal robot with vertebrae, disks, a nuchal ligament and thin McKibben pneuma...
In recent years, soft actuators with flexibility and high compliance increasingly attract attention in robotics. The dielectric elastomer actuator (DEA), a kind of electroactive polymer actuators, consists of a dielectric elastomer film and compliant electrodes. The voltage-induced deformations are further improved by pre-stretching the film. To de...
Recently, various soft actuators with biologically inspired motions have emerged in the field of robotics. The present study focuses on the development of a multi-balloon dielectric elastomer actuator (DEA) to provide a traveling wave motion for the linear transportation of an object. The multi-balloon actuator is designed on the basis of a pneumat...
Artificial multi-joint musculoskeletal systems consisting of serially connected links driven by monoarticular and multiarticular muscles, which are often inspired by vertebrates, enable robots to elicit dynamic, elegant, and flexible movements. However, serial links driven by multiarticular muscles can cause unstable motion (e.g., buckling). The st...
This letter proposes a novel method to accomplish shape recognition by utilizing a tensegrity structure with a soft sensor via a recurrent neural network (RNN). The combination of soft tensegrity and soft sensors make it capable of recognizing the deformation to reflect the shape of its surroundings. As the first step to this goal, we build a three...
This article discusses the stabilization in longitudinal elastic modulus of braided high modulus polyethylene rope for dynamic loading in tendon-driven robot by mean of preload treatment. Dynamic loading was presented by impact loading which expressed in term of number of drops applied on the rope. Different preload levels were applied on the ropes...
The exploration and inspection of narrow spaces in industrial plants require the use of long-reach redundant manipulators with large three-dimensional (3D) workspaces. To this end, in a previous work, a coupled tendon-driven articulated manipulator with a total length of 10 m and yaw joints for 3D motion was developed. This study focuses on employi...
Pneumatic actuators afford advantages such as flexibility, low weight, and explosion-proofness. However, increasing the number of pressure supply tubes and using solenoid valves in a multi-degree-of-freedom system may negate these advantages. Therefore, this study proposes a soft actuator that uses self-excited vibrations realized by using an airfl...
Long robotic arms are useful for many applications such as nuclear plant decommissioning, inspection, and firefighting. A major problem for designing and operating long robotic arms is that even small end effector reaction forces and arm gravity can result in large loads on proximal arm joints because of long moment arms. To solve that problem, pre...
Power soft robots—defined as novel robots driven by powerful soft actuators, achieving both powerfulness and softness—are potentially suitable for complex collaborative tasks, and an approach to actuating a power soft robot is the McKibben artificial muscle. This study aims to show the potential of hydraulic artificial muscles to be implemented in...
In recent years, research on soft robots has become popular due to the improvement of forming technology of flexible materials. In particular, soft robots powered by air pressure support the flexibility and lightness that can not be found in modern robots. The pneumatic actuators are expected to be active in many situations because they are highly...
The neck of Giraffe has excellent characteristics as a long robot mechanism. The neck of giraffe can move violently represented in necking, a motion striking necks each other. Further, in a necking motion, a neck of a giraffe wards off impacts and adapts to the shape of the opponent. On the other hand, conventional robot mechanisms have hardly achi...
An ionic polymer metal composite (IPMC) actuator is one of the electroactive polymer devices. To realize arbitrary 3D-shaped IPMC actuators, we have proposed a novel fabrication method of IPMC actuators. With the support of paper or fabric, IPMC actuators of any three-dimensional shape can be manufactured. In this paper, such IPMCs are called PF-IP...