Kenjiro Tadakuma

Kenjiro Tadakuma
Osaka University | Handai · School of Engineering

About

303
Publications
57,996
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1,175
Citations
Citations since 2016
190 Research Items
790 Citations
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200

Publications

Publications (303)
Preprint
Full-text available
This paper presents a vision-based in-hand manipulation method. Picking up an object from a pile is an important task for a robotic hand. In particular, for objects of various sizes, weights, and hardness, it is necessary to detect slippage between the object and the surface of the hand. Meanwhile, dexterously changing the position and orientation...
Article
Full-text available
As considerable amounts of welding are required during ship construction, robotic automation is being promoted. However, current welding robots do not automate work in high or narrow places. One reason is that welding cannot be performed with sufficient accuracy because a welding robot with a torch cannot tow a heavy cable and thus may go off path....
Article
Full-text available
A two-degrees-of-freedom spherical parallel link mechanism (2-DOF SPM) was designed to ensure that it only has rotational degrees of freedom in two directions around a fixed center. In general, 2-DOF SPM includes passive rotating pairs, and at least two actuators are needed to change the end-effector posture. The arrangement of the links and pairs...
Article
This paper describes a plant inspection robot team consisting of three types of robots that won the World Robot Summit 2020 plant disaster prevention challenge. There is a social demand to use robots for industrial plant inspection tasks to decrease the workload and risks of human operators. In this study, the authors developed a plant inspection s...
Article
Cursorial quadrupeds have different connections to the trunk for forelimbs and hindlimbs: a flexible connection through the muscles to the forelimb, and a secure connection through the hip joint to the hindlimb. Although anatomical and biological studies have described the structure and behavior of cursorial quadrupeds by focusing on flexible shoul...
Article
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....
Article
Recently, soft robotics research has focused on mechanisms to control the stiffness of robot structures. There are several types of variable stiffness mechanisms that can change the stiffness of such structures by altering friction force. Among these, the negative-pressurization method applies negative pressure to the particles or layers that are f...
Article
This letter proposes a novel pneumatic soft robotic hand that incorporates a mechanism that can switch the airflow path using a single airflow control. The developed hand can control the finger motion and operate the surface friction variable mechanism. In the friction variable mechanism, a lubricant is injected onto the high-friction finger surfac...
Preprint
This paper proposes a novel pneumatic soft robotic hand that incorporates a mechanism that can switch the airflow path using a single airflow control. The developed hand can control the finger motion and operate the surface friction variable mechanism. In the friction variable mechanism, a lubricant is injected onto the high-friction finger surface...
Preprint
Inflatable structures used in soft robotics applications exhibit unique characteristics. In particular, the tip-extension structure, which grows from the tip, can grow without friction against the environment. However, these inflatable structures are inferior to rigid mechanisms in terms of their load-bearing capacity. The stiffness of the tip-exte...
Article
Full-text available
Electromagnetic (EM) brakes are widely used but consume electricity continuously to maintain their activated state. In this paper, for efficient braking and idling of robots and vehicles, we proposed a concept of a brake mechanism using a permanent magnet for the amplification of the pressing force between brake pads, allowing for the brake torque...
Article
Full-text available
Fluid jet actuation is one of the potential actuation techniques for continuum robots. It can generate and rapidly control a relatively large force using a small and lightweight structure because a significant amount of energy can be transported through its internal channels. Recently, jet-actuated flying continuum robots have been developed using...
Article
Full-text available
Flexible continuum robots have considerable potential for use in exploring intricate spaces, and their ability to make large body shape deformations can increase the inspection area. We previously proposed a jet-actuated flying continuum robot for extinguishing fires. The main challenge in implementing large shape deformations is accommodating the...
Article
The mobility on rough terrain is a crucial factor in designing rescue robots. Rubbles scattered across disaster site obstruct the robots, which may limit search areas and disturb rapid rescue. To improve mobility in such situations, we proposed a novel mobile mechanism, called mono-wheel track (MW-track), which is an elastic track driven by a singl...
Article
Inflatable structures used in soft robotics applications have unique characteristics. In particular, the tip-extension structure, which extends the structure from its tip, can grow without creating friction with the environment. However, these inflatable structures need high pressure to maintain their stiffness under various conditions. Excessive i...
Article
Full-text available
Machines such as robotic grippers use powerful actuators or gearboxes to exert large loads at the expense of energy consumption, volume, and mass. We propose a stepless force amplification mechanism that assists clamping by a pair of permanent magnets, in which the external control force required to adjust their distance, and thus the output force,...
Article
There are many researches and development of the roller tube pumps, such as peristaltic pumps. This time, we considered the mixing function with two differential roller arms driving for this roller tube pump which has one single continuous tube. We conducted experiments using actual prototype mechanisms and confirmed that the inventive principle is...
Article
Fluid injection has promising potential as a novel actuation approach for robots to enable the rapid switching of large forces. The proposed nozzle unit can drastically expand the injection range using a passive rotation mechanism to automatically follow the intended injection direction. Concretely, the nozzle unit consists of the passive joint to...
Article
Quadrupeds can generate adaptive limb trajectories according to the locomotion speeds and road conditions. An essential factor in the adaptive locomotion of animals is flexibility of tendons. Animal tendons have a notable nonlinear property, where it responds with lower stiffness for relatively small displacement, and higher stiffness for larger di...
Article
In this paper, we propose a novel pneumatic-driven variable stiffness mechanism capable of shape-locking. Various methods had been proposed to change the stiffness. However, there is no simple methodology to realize both controllable elasticity and shape locking. In this research, we present a continuum robot using flat tubes pathed through along t...
Article
The omnidirectional motion can move any direction without changing the direction of its own. The authors have developed Wave-wheel mechanism and Screw-type differential rotating mechanism. Also, the stepping performance were improved by extending the ground point from point to line. In addition, we have evaluated the motion characteristics of one c...
Article
Our team developed mechanism that aims securing regidity and reducing weight of UAV by constructing with box-shape objects. It is a mechanism that feeds out box-shaped objects one by one, and the transfer efficiency is improved by performing multiple transfers. In this paper, we describe the trial production and operation test of the individual fee...
Article
The authors have been developing a swarm robot system to automate long distance welding in narrow and high places, which cannot be handled by existing welding robots. In welding operations, it is necessary to tow not only the welding torch but also the cables that supply welding wire and gas to the torch. In addition, when welding in a narrow space...
Article
Most of the welding robots are either large and non-mobile manipulators or small vehicles that do not have an autonomous navigation function. Therefore, they cannot be used for long distance welding in narrow or high places. For this problem, this paper proposes a swarm robot system for automating long distance welding in narrow or high places. The...
Article
Cursorial quadrupeds have sophisticated morphology with heterogeneity along with the lead to tail direction, realizing agile locomotor capabilities. This study aims to understand the functionality underlying the asymmetrical animal morphology to establish a new design principle beyond modern-day quadruped robots with homogeneous body structures. To...
Article
Stiffness changing mechanism is what switches the stiffness of a structure to take advantage of both "low stiffness" and "high stiffness" functions. Several methods using fluid power and wire systems have been proposed. In this paper, we propose a new method to switch the stiffness by changing the value of the moment of inertia of area, which is di...
Article
Soft robots, made of elastomers and gels tend to easily break, punctured, or torn by contact with sharp and thin objects. To deal with this problem, we had proposed a robotic blood vessel mechanism that has a self-healing function by inserting liquid-filled blood vessels in the body. their bodies themselves. The liquid flows out and is cured which...
Article
The 2-DOF spherical parallel link mechanism (2-DOF SPM) has been applied to the direction operation of cameras because the error due to link deformation and the torque applied to the actuators are small. However, the range of motion is narrow because it is easy to transfer into a singular posture and parts interference is likely to occur. This stud...
Article
Quadrupeds have an ability to autonomously generate locomotion in response to their environment by using a large number of reflex feedbacks throughout their body. We have been proposing a design method to implement a mechanical reflex system in a robot to reproduce the animals’ abilities. In this study, a robot resembling feline hindlimbs with a co...
Article
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...
Article
Body parts of modern quadruped robots, including front legs, have few degrees of freedom. In contrast, animals such as Felidae have their forelimbs with many degrees of freedom, and achieve a variety of actions (e.g. walking, climbing, and attacking). This study aimed to understand the mechanism how the complex forelimb structure functions in reali...
Article
This paper describes the force diode mechanism which realize the reverse input prevention. Based on the basic principle we considered, the mechanical prototype model has been built and basic experiments with this prototype have been done so that the fundamental function and effect of the basic idea of the force diode mechanism.
Article
Grippers with soft structures can be adapted to the object shapes, making it possible to handle various items without complicated control. They can change their apparent stiffness, for example, by using MR fluids or pin-array structures. However, MR fluid grippers have difficulty propagating magnetic flux to MR fluids. Pin-array grippers also have...
Article
Jamming grippers and actuators are gaining popularity in soft robotics application. The ideal material for such applications should include properties like wide range of stiffness variation, high degree of self-restoration, good deformation and extensibility, and ability of shape adoption. Current working materials like fluids, elastomers, granular...
Article
Modern-day quadruped robots are expanding their versatility on tasks like patrolling and manipulating by the implementation of an additional robot manipulator like the neck of the animal. During locomotion, However, the extra robotic arm harms the robot’s locomotor capability and efficiency due to the additional weight. To solve this problem, this...
Article
Thin construction is an advantage in the design of mechanisms. Among them, the soft-bending thin sheet actuator can fit into the shape of an object and grasp it after inserting a finger into a narrow space. However, to facilitate bending, these mechanisms have a small thickness or made of soft materials, which lead to a low stiffness. In this study...
Article
Fluid injection has promising potential as a novel actuation approach for robots to enable the rapid switching of large forces. We have proposed a nozzle unit with multiple active rotating nozzles for controlling the magnitude and direction of the net force simultaneously. However, a new fundamental challenge arises when multiple nozzle units are c...
Article
Omnidirectional mobility is a popular method of moving in narrow spaces. In particular, the planar omnidirectional crawler previously developed by the authors can traverse unstable and uneven terrain with a large contact area. A novel point is that the proposed system is unique in its ability to carry heavy loads in all directions without getting s...
Conference Paper
Full-text available
CURSOR (Coordinated Use of miniaturized Robotic equipment and advanced Sensors for search and rescue OpeRations) is an ongoing European H2020 project with the main objective to enhance the efficiency and safety of Urban Search and Rescue (USaR) operations on disaster sites. CURSOR’ s approach relies on the integration of multiple mature and emergin...
Article
Full-text available
This article presents an active ball joint mechanism (ABENICS) enhanced by interactions of spherical gears. The gear-based joint drives three rotational degrees of freedom (RDoF) without slippage. The capabilities were inspired by the unique interactions between two different innovative gears [the cross spherical gear (CS-gear) and monopole gear (M...
Article
For rescue or endoscope applications, snake-like robots have been extensively studied to access and explore confined spaces, such as small-diameter holes or complicated debris. Among them, toroidal structures that eversion the surface flexible membrane exhibit high-mobility performance, even in fragile or soft ground because they can move without f...
Article
Full-text available
Most articulated robots comprise multiple joints and links that control the position and posture of the end effector. The kinematic pair arrangement determines characteristics such as output force. The link configurations can be classified into serial link and parallel link mechanisms. A typical parallel link mechanism is the spherical parallel mec...
Article
In the past, white canes, guide dogs, and guide helpers have served to assist visually impaired people when walking outdoors. However, these assistance methods have various limitations for extended and suitable usage. Therefore, our laboratory herein proposes a route guidance device that signals commands to the end-user by giving a sense of force t...
Article
The force required to drive a mechanism can be compensated by adding an equivalent load in the opposite direction. By reversing the input and output of the load compensation, we proposed the concept of a displacement-force converter that enables the deformation of the elastic element to be controlled steplessly by a minimal external force. Its prin...
Article
Various researches are conducted to reduce the influence of winds and waves for safer work environment on offshore operations and to negate the tilt due to acceleration of vehicle for improved comfortableness. Conventional researches have adopted active mechanism like six-degree-of-freedom parallel mechanism that absorbs the sway by constantly keep...
Article
This study was related to a holonomic omnidirectional mobile robot, particularly, a mobile robot with a wheel mechanism that can generate an omnidirectional driving force with a single unit based on Cross Helical Gear mechanism. In this paper, grousers were added to the wheel for improving step climbing ability. A vehicle using multiple active Dual...
Article
A snake-type robot using water injection is expected to be applied to fire fighting activities of a disaster. We have developed a Dragon FireFighter (DFF), a flexible snake-like robot using water jets for fire fighting. In this research, we improve the DFF reliability for increase the length of its. In this paper, we developed a metal nozzle module...
Article
Edible materials have been utilized for soft robots and made them biodegradable and biocompatible. So far, the authors have devised and realized not only soft edible robotic elements but also hard edible materials essential to tasks such as insertion into a narrow environment. However, hard materials tend to require casting mold and thus have infea...
Article
We have proposed a jamming membrane mechanism and a one-dimensional jamming mechanism as variable stiffness mechanism. These can be used as grippers that can firmly grasp complex shape objects. However, it is difficult for the jamming membrane gripper to grasp sharp objects, and for the one-dimensional jamming mechanism gripper to grasp fine object...
Article
Currently, drone research and development has received significant attention worldwide. Particularly, delivery services employ drones as it is a viable method to improve delivery efficiency by using a several unmanned drones. However, regarding the takeoff and landing port of the drones, the continuous landing of multiple drones has not been realiz...
Article
Modern–day quadruped robots are designed to possess symmetrical body and limbs, for good balance and modularity. On the other hand, animal morphology is sophisticated and has obtained heterogeneity along the cephalocaudal direction, realizing adaptive locomotion. This study aims to understand the functionality of the cephalocaudal heterogeneous ani...
Article
Soft actuators have advantages, including large deformation, safety and adaptability to the environment, and shock absorbance. However, they are weak against sharp objects due to their soft bodies. This paper proposes a protective skin mechanism with an exhaustive arrangement of tiny rigid bodies. Small pieces were sewed on an elastic sheet by Kevl...
Article
Soft robots have a problem that they easily punctured or torn by contact with a sharp edge due to their soft bodies made of weak materials. To solve this fundamental issue, we proposed a robotic blood vessel mechanism that enables the robot to heal their bodies themselves. This mechanism realizes the self-healing function of soft robots like blood...
Article
Soft robots have attracted much attention in recent years owing to their high adaptability. Long articulated soft robots enable diverse operations, and tip-extending robots that navigate their environment through growth are highly effective in robotic search applications. Since the robot membrane extends from the tip, these robots can lengthen with...
Article
Thinning is one of the important themes in mechanism development. But it is difficult to increase the stiffness of a thin actuator. Body stiffness depends on moment of inertia of area and Young's modulus. Since the thin actuator maintains a constant cross section while bending. Even if sheet metal material with a high Young's modulus is used, its s...
Article
We proposed a fluid-driven jamming mechanism that realizes a variable stiffness mechanism by using pressurization. In this mechanism, a rubber tube is enclosed inside a hollow linear body. When this tube is expanded by fluid pressure, the linear body can be held in any shape. Since the fluid pressure is used, the force can be transmitted even if th...
Article
Quadrupeds have an excellent ability to generate various limb trajectories according to locomotion speeds and road conditions. In order to investigate the source of the ability, we developed a hind body robot with hindlimb models of horses. The hindlimb model has major six tendons in houses’ hindlimb that contribute to provide interlocking of multi...
Article
We developed Rigid Bone Parachute, which avoid tangling with using rigid bone link instead of wire. It can open rapidly and start deceleration earlier with spring. We performed drop test of Rigid Bone Parachute with two-wheel rover robot and confirmed its ability of avoidance of tangling. We measured its speed transition by motion capture and confi...
Article
The omnidirectional motion can move any direction without changing the direction of its own. The authors have developed Wave-wheel mechanism and Screw-type differential rotating mechanism. Also, the stepping performance were improved by extending the ground point from point to line. In addition, we have evaluated the motion characteristics of one c...
Article
Soft robots have attracted much attention in recent years owing to their high adaptability. Long articulated soft robots enable diverse operations, and tip-extending robots that navigate their environment through growth are highly effective in robotic search applications. Robots that extend from the tip can lengthen their body without friction from...
Article
Several ground-based robots have been developed to support dangerous fire extinguishing activities; however, in such cases, it is difficult to access the fire sources directly. The concept of a hose-type robot called ‘dragon firefighter’ (DFF) is proposed herein; it emits high-pressure water from a fire hose and floats it for direct transmission to...