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Kenjiro Tadakuma

46 accepted papers

2026

Drone Landing Performance in Windy Conditions: Comparing the Vertical and Horizontal Landing Approaches with the EAGLES Port

Iuri Pereira Barros, Yoshito Okada, Kenjiro Tadakuma, Masahiro Watanabe, Masashi Konyo, Kazunori Ohno +3
ICRA 2026poster

Drone docking stations promote efficient operations of drones, but they usually support only one vehicle, and are accessible primarily through vertical landing. These limitations hinder multi-drone operations and result in challenges for fast, precise docking, particularly under severe wind conditio…

Cited by 0Source ↗Scholar ↗
2025

Poloidal Drive: Direct-Drive Transmission Mechanism for Active Omni-Wheels With Spoke Interference Avoidance

Shunsuke Sano, Kenjiro Tadakuma, Ryotaro Kayawake, Masahiro Watanabe, Kazuki Abe, Yuto Kemmotsu +1
RA-L 2025

Wheels require extra space for steering. Omnidirectional wheels are ideal for confined spaces as they can move in all directions: forward/backward and left/right. Conventional omnidirectional wheels with passive rollers achieve this movement by combining multiple wheels. However, if even one wheel l

Cited by 2Source ↗Scholar ↗
2025

Tube Mechanism for Positively Pressurized Variable Stiffness by Lever and Wire

Issei Onda, Masahiro Watanabe, Kenjiro Tadakuma, Kazuki Abe, Satoshi Tadokoro
RA-L 2025

In the field of soft robotics, research on variable stiffness mechanisms that combine flexible structures for deformation with a solid structure for transmitting external forces is underway. This investigation is focused on a mechanism for achieving a high adjustable locking force with minimal actua

Cited by 1Source ↗Scholar ↗
2024

A Modular, Tendon Driven Variable Stiffness Manipulator with Internal Routing for Improved Stability and Increased Payload Capacity

Kyle L. Walker, Alix J. Partridge, Hsing-Yu Chen, Rahul R. Ramachandran, Adam A. Stokes, Kenjiro Tadakuma +2
ICRA 2024poster

Stability and reliable operation under a spectrum of environmental conditions is still an open challenge for soft and continuum style manipulators. The inability to carry sufficient load and effectively reject external disturbances are two drawbacks which limit the scale of continuum designs, preven…

Cited by 1Source ↗Scholar ↗
2024

Balloon Pin-Array Gripper: Two-Step Shape Adaptation Mechanism for Stable Grasping Against Object Misalignment

Yuto Kemmotsu, Kenjiro Tadakuma, Kazuki Abe, Masahiro Watanabe, Satoshi Tadokoro
RA-L 2024

This letter introduces a balloon pin-array gripper combining shape adaptability to various objects, stable holding by multipoint contact, and isotropic grasping performance. This is particularly useful when the shape or position of the objects cannot be accurately determined because of sensor limita

Cited by 10Source ↗Scholar ↗
2024

Enhanced Omni-Ball: Spherical Omnidirectional Wheel Achieving Passive Rollers with High Load Capacity and Smoothness through an Offset Rotational Axis

Kenjiro Tadakuma, Seiji Sakiyama, Eri Takane, Riichiro Tadakuma, Satoshi Tadokoro
IROS 2024poster

This paper introduces an innovation of the Spherical Omnidirectional Wheel, designed to achieve omnidirectional driving motion. In previous models, the supporting shaft was placed at the center of the mechanism. However, achieving both smoothness and high load-capacity in such designs proved challen…

Cited by 0Source ↗Scholar ↗
2024

Flexible Omnidirectional Driving Gear Mechanism with Adaptation over Arbitrary Curvatures

Moses Gladson Selvamuthu, Kazuki Abe, Kenjiro Tadakuma, Riichiro Tadakuma
ICRA 2024poster

A support structure for flexible displays such as OLED or flexible LEDs was developed using the flexible omnidirectional driving gear mechanism. It is a gear mechanism having two degrees of freedom on one surface. This flexible display mechanism is expected to be placed inside a car dashboard as a h…

Cited by 0Source ↗Scholar ↗
2024

Tube Mechanism With 3-Axis Rotary Joints Structure to Achieve Variable Stiffness Using Positive Pressure

Issei Onda, Masahiro Watanabe, Kenjiro Tadakuma, Kazuki Abe, Satoshi Tadokoro
RA-L 2024

Studies on soft robotics have explored mechanisms of switching the stiffness of a robot structure. The hybrid soft-rigid approach, which combines soft materials and high-rigidity structures, is the most commonly-used method for the variable stiffness mechanism. The positive-pressurization method, in

Cited by 6Source ↗Scholar ↗
2024

Versatile Variable-Stiffness Scooping End-Effector: Tilting-Scooping-Transfer Mechanism for Objects with Various Properties

Yuta Takahashi, Kenjiro Tadakuma, Kazuki Abe, Masahiro Watanabe, Shoya Shimizu, Satoshi Tadokoro
IROS 2024poster

To address the setup and changeover time issues in high-mix, low-volume production systems, we developed an end-effector capable of uniformly scooping, holding, and transporting a wide variety of objects, and demonstrated this system with prototype. Our experiments showed that the prototype was succ…

Cited by 0Source ↗Scholar ↗
2023

A New Design of Multilayered String Jamming Mechanism with Three-Degree-of-Freedom

Ryohei Michikawa, Kenjiro Tadakuma, Fumitoshi Matsuno
IROS 2023poster

A robot must exhibit softness so as not to accidentally damage its environment. However, stiffness is also necessary, so that the robot can transmit forces and perform tasks. In soft robotics, it is desirable to be able to switch between two states, namely a flexible state for adapt ion to the envir…

Cited by 1Source ↗Scholar ↗
2023

Flexible and Slim Device Switching Air Blowing and Suction by a Single Airflow Control

Seita Nojiri, Toshihiro Nishimura, Kenjiro Tadakuma, Tetsuyou Watanabe
RA-L 2023

This study proposes a soft robotic device with a slim and flexible body that switches between air blowing and suction with a single airflow control. Suction is achieved by jet flow entraining surrounding air, and blowing is achieved by blocking and reversing jet flow. The thin and flexible flap gate

Cited by 3Source ↗Scholar ↗
2023

Inflated Bendable Eversion Cantilever Mechanism With Inner Skeleton for Increased Stiffness

Tomoya Takahashi, Masahiro Watanabe, Kazuki Abe, Kenjiro Tadakuma, Naoto Saiki, Masashi Konyo +1
RA-L 2023

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 the

Cited by 13Source ↗Scholar ↗
2023

Permanent-Magnetically Amplified Robotic Gripper With Less Clamping Width Influence on Compensation Realized by a Stepless Width Adjustment Mechanism

Tori Shimizu, Kenjiro Tadakuma, Masahiro Watanabe, Kazuki Abe, Masashi Konyo, Satoshi Tadokoro
RA-L 2023

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

Cited by 0Source ↗Scholar ↗
2023

Protective Skin Mechanism with an Exhaustive Arrangement of Tiny Rigid Bodies for Soft Robots: Evaluation of Puncture Resistance, Elasticity, and Descaling Resistance of the Scale Mechanism

Kenjiro Tadakuma, Masahiro Watanabe, Satoshi Tadokoro
IROS 2023poster

Soft actuators have several advantages, including large deformation, safety and adaptability to the environment, and shock absorbance. However, they are weak against sharp objects owing to their soft bodies. This paper proposes a novel protective skin mechanism with an exhaustive arrangement of tiny…

Cited by 0Source ↗Scholar ↗
2023

Translational Disturbance Rejection for Jet-Actuated Flying Continuum Robots on Mobile Bases

Yukihiro Maezawa, Yuichi Ambe, Yu Yamauchi, Masashi Konyo, Kenjiro Tadakuma, Satoshi Tadokoro
RA-L 2023

Although continuum robots have the potential to operate in narrow areas by changing their shapes and propelling their bodies, they easily vibrate under sudden or periodic applications of external forces. Suppressing vibrations is difficult in our jet-actuated continuum robot because the movements of

Cited by 6Source ↗Scholar ↗
2022

Anisotropic-Stiffness Belt in Mono wheeled Flexible Track for Rough Terrain Locomotion

Yu Ozawa, Masahiro Watanabe, Kenjiro Tadakuma, Satoshi Tadokoro
IROS 2022poster

Rescue robots that search around on debris during natural disasters require high mobility to overcome various shaped materials scattered in the environment. Our previous study developed a new tracked mechanism called Mono-wheel Track, an elastic track driven by a single wheel, having a high capabili…

Cited by 2Source ↗Scholar ↗
2022

Cooperative Towing by Multi-Robot System That Maintains Welding Cable in Optimized Shape

Ryota Suzuki, Yoshito Okada, Yoshiki Yokota, Tatsuyoshi Saijo, Haruhiko Eto, Yuya Sakai +4
RA-L 2022

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

Cited by 7Source ↗Scholar ↗
2022

Experimental Study of the Mechanical Properties of a Spherical Parallel Link Mechanism With Arc Prismatic Pairs

Naoto Saiki, Kenjiro Tadakuma, Masahiro Watanabe, Kazuki Abe, Masashi Konyo, Satoshi Tadokoro
RA-L 2022

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-effecto

Cited by 2Source ↗Scholar ↗
2022

Highly Articulated Tube Mechanism With Variable Stiffness and Shape Restoration Using a Pneumatic Actuator

Issei Onda, Kenjiro Tadakuma, Masahiro Watanabe, Kazuki Abe, Tetsuyou Watanabe, Masashi Konyo +1
RA-L 2022

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 negat

Cited by 8Source ↗Scholar ↗
2022

Permanent-Magnetically Amplified Brake Mechanism Compensated and Stroke-Shortened by a Multistage Nonlinear Spring

Tori Shimizu, Kenjiro Tadakuma, Masahiro Watanabe, Kazuki Abe, Masashi Konyo, Satoshi Tadokoro
RA-L 2022

Electromagnetic (EM) brakes are widely used but consume electricity continuously to maintain their activated state. In this letter, 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

Cited by 1Source ↗Scholar ↗
2022

Soft Robotic Hand With Finger-Bending/Friction-Reduction Switching Mechanism Through 1-Degree-of-Freedom Flow Control

Toshihiro Nishimura, Kensuke Shimizu, Seita Nojiri, Kenjiro Tadakuma, Yosuke Suzuki, Tokuo Tsuji +1
RA-L 2022

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 lubrican

Cited by 16Source ↗Scholar ↗
2022

Toroidal Origami Monotrack: Mechanism to Realize Smooth Driving and Bending for Closed-Skin-Drive Robots

Masahiro Watanabe, Yuto Kemmotsu, Kenjiro Tadakuma, Kazuki Abe, Masashi Konyo, Satoshi Tadokoro
IROS 2022poster

We propose a novel toroidal origami monotrack capable of smooth-skin driving and bending for closed-skin-drive robots. Monotracks are a promising solution for achieving high mobility in unstructured environments. Toroidal-drive mechanisms enable whole skin drive; however, conventional methods experi…

Cited by 2Source ↗Scholar ↗
2021

2-DOF Spherical Parallel Mechanism Capable of Biaxial Swing Motion with Active Arc Sliders

Naoto Saiki, Kenjiro Tadakuma, Masahiro Watanabe, Eri Takane, Masashi Nobutoki, Shintaro Suzuki +2
RA-L 2021

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 as serial link and parallel link mechanisms. A typical paral

Cited by 8Source ↗Scholar ↗
2021

Amplification of Clamping Mechanism Using Internally-Balanced Magnetic Unit

Tori Shimizu, Kenjiro Tadakuma, Masahiro Watanabe, Eri Takane, Masashi Konyo, Satoshi Tadokoro
IROS 2021poster

Machines tend to use powerful actuators and large gearboxes to bear large loads, which are inconvenient in terms of responsiveness as they affect the duration of operations. Thus, to compensate the force to grasp an object, we propose a clamping mechanism implementing the internally-balanced magneti…

Cited by 1Source ↗Scholar ↗
2021

Eversion Robotic Mechanism With Hydraulic Skeletonto Realize Steering Function

Tomoya Takahashi, Kenjiro Tadakuma, Masahiro Watanabe, Eri Takane, Natsumi Hookabe, Hiroshi Kajihara +3
RA-L 2021

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, eversion robot which can evert their flexible surface membrane to extend, exhibit high-mobility performance, ev

Cited by 26Source ↗Scholar ↗
2021

HueCode: A Meta-marker Exposing Relative Pose and Additional Information in Different Colored Layers

Yoshito Okada, Daiki Fujikura, Yu Ozawa, Kenjiro Tadakuma, Kazunori Ohno, Satoshi Tadokoro
ICRA 2021poster

In this paper, HueCode, a meta-marker that robustly and simultaneously exposes the relative pose between a marker and a camera along with additional information, is proposed. It occupies the area of a single marker by overlaying multiple types of markers in different colored layers. Using perspectiv…

Cited by 12Source ↗Scholar ↗
2021

Internally-Balanced Displacement-Force Converter for Stepless Control of Spring Deformation Compensated by Cam With Variable Pressure Angle

Tori Shimizu, Kenjiro Tadakuma, Masahiro Watanabe, Eri Takane, Masashi Konyo, Satoshi Tadokoro
RA-L 2021

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 controlle

Cited by 1Source ↗Scholar ↗
2021

Passive Orientation Control of Nozzle Unit With Multiple Water Jets to Expand the Net Force Direction Range for Aerial Hose-Type Robots

Yu Yamauchi, Yuichi Ambe, Masashi Konyo, Kenjiro Tadakuma, Satoshi Tadokoro
RA-L 2021

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

Cited by 10Source ↗Scholar ↗
2021

Two-Sheet Type Rotary-Driven Thin Bending Mechanism Realizing High Stiffness

Tomoya Takahashi, Masahiro Watanabe, Kenjiro Tadakuma, Eri Takane, Masashi Konyo, Satoshi Tadokoro
RA-L 2021

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 are thin or made of soft materials, which le

Cited by 2Source ↗Scholar ↗
2020

A Bio–inspired Quadruped Robot Exploiting Flexible Shoulder for Stable and Efficient Walking

Akira Fukuhara, Megu Gunji, Yoichi Masuda, Kenjiro Tadakuma, Akio Ishiguro
IROS 2020poster

While most modern-day quadruped robots crouch their limbs during the stance phase to stabilize the trunk, mammals exploit the inverted-pendulum motions of their limbs and realize both efficient and stable walking. Although the flexibility of the shoulder region of mammals is expected to contribute t…

Cited by 13Source ↗Scholar ↗
2020

Bundled Rotary Helix Drive Mechanism Capable of Smooth Peristaltic Movement

Masahiro Watanabe, Kenjiro Tadakuma, Masashi Konyo, Satoshi Tadokoro
RA-L 2020

Herein, we focus on the design method of a robot, named Wave Wheel, capable of generating a smooth continuous peristaltic wave, which is driven by a bundled rotary helix drive mechanism. Wave Wheel mainly consists of a braided mesh tube, multiple helices that are arranged on the circumference, and s

Cited by 12Source ↗Scholar ↗
2020

Emergence of Swing-to-Stance Transition from Interlocking Mechanism in Horse Hindlimb

Kazuhiro Miyashita, Yoichi Masuda, Megu Gunji, Akira Fukuhara, Kenjiro Tadakuma, Masato Ishikawa
IROS 2020poster

The bodies of quadrupeds have very complex muscle-tendon structure. In particular, it is known that in the horse hindlimb, multiple joints in the leg are remarkably interlocked due to the muscle-tendon structure. Although the function of these interlocking mechanisms during standing has been investi…

Cited by 24Source ↗Scholar ↗
2020

Internally-Balanced Magnetic Mechanisms Using a Magnetic Spring for Producing a Large Amplified Clamping Force

Tori Shimizu, Kenjiro Tadakuma, Masahiro Watanabe, Eri Takane, Masashi Konyo, Satoshi Tadokoro
ICRA 2020poster

To detach a permanent magnet using a control force much smaller than its original attractive force, the internally-balanced magnetic unit (IB Magnet) was invented. It has been applied to magnetic devices such as wall-climbing robots, ceiling-dangling drones, and modular swarm robots. In contrast to…

Cited by 7Source ↗Scholar ↗
2020

Radial-Layer Jamming Mechanism for String Configuration

Rio Mukaide, Masahiro Watanabe, Kenjiro Tadakuma, Yu Ozawa, Tomoya Takahashi, Masashi Konyo +1
RA-L 2020

In the soft robotics field, soft structures are required for safe human interactions, adaptive shape grippers, and haptic interfaces. Conversely, rigid structures are necessary for high force transmission devices and precise position control applications. The tunable stiffness mechanism is a crucial

Cited by 22Source ↗Scholar ↗
2020

Retraction Mechanism of Soft Torus Robot With a Hydrostatic Skeleton

Tomoya Takahashi, Masahiro Watanabe, Kenjiro Tadakuma, Masashi Konyo, Satoshi Tadokoro
RA-L 2020

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

Cited by 17Source ↗Scholar ↗
2020

Toward Enabling a Hundred Drones to Land in a Minute

Daiki Fujikura, Kenjiro Tadakuma, Masahiro Watanabe, Yoshito Okada, Kazunori Ohno, Satoshi Tadokoro
IROS 2020poster

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. Research has been conducted to realize complete automation of drone contro…

Cited by 4Source ↗Scholar ↗
2019

A Mechanical Approach to Suppress the Oscillation of a Long Continuum Robot Flying With Water Jets

Tomoka Yamaguchi, Yuichi Ambe, Hisato Ando, Masashi Konyo, Kenjiro Tadakuma, Shigenao Maruyama +1
RA-L 2019

Flexible continuum robots exhibit a strong potential for approaching narrow and intricate spaces. However, such long flexible bodies often experience oscillations, making them unstable. To enhance their performance in order to realize rapid and precise movements, unnecessary vibrations should be sup

Cited by 20Source ↗Scholar ↗
2019

Basic Performance of Planar Omnidirectional Crawler during Direction Switching using Disturbance Degree of Ground Evaluation Method

Eri Takane, Kenjiro Tadakuma, Tori Shimizu, Sosuke Hayashi, Masahiro Watanabe, Shingo Kagami +3
IROS 2019poster

We introduced the disturbance degree of ground and proposed an evaluation method to measure the mobile performance of a crawler on soft ground during direction switching. First, we developed a planar omnidirectional crawler, which had a configuration with two left and right unit crawlers for perform…

Cited by 4Source ↗Scholar ↗
2019

Development and Experimental Validation of Aerial Vehicle With Passive Rotating Shell on Each Rotor

Carl John Salaan, Kenjiro Tadakuma, Yoshito Okada, Yusuke Sakai, Kazunori Ohno, Satoshi Tadokoro
RA-L 2019

Aerial robotics is a fast-growing field of robotics and has been successfully used in various applications. Still, it faces many challenges, such as dealing with unavoidable obstacles in a cluttered environment. Recently, a flying robot with a protective shell that can rotate passively was introduce

Cited by 40Source ↗Scholar ↗
2018

Aerial Hose Type Robot by Water Jet for Fire Fighting

Hisato Ando, Yuichi Ambe, Akihiro Ishii, Masashi Konyo, Kenjiro Tadakuma, Shigenao Maruyama +1
RA-L 2018

Disaster response, especially fire-fighting and rescue, is highly risky for firefighters engaged in action. As a result, many robots intended for fire-fighting have been proposed. However, it is difficult for them to directly access fire sources because their mobility is limited. Specifically, exist

Cited by 70Source ↗Scholar ↗
2018

Design and Development of Biaxial Active Nozzle with Flexible Flow Channel for Air Floating Active Scope Camera

Akihiro Ishii, Yuichi Ambe, Yu Yamauchi, Hisato Ando, Masashi Konyo, Kenjiro Tadakuma +1
IROS 2018poster

Long flexible continuum robots have a high potential for search and rescue operations that explore deep layered debris. A general problem of these robots is in the control of the head motion because their thin bodies limit the space available to mount multiple actuators. This paper develops a biaxia…

Cited by 23Source ↗Scholar ↗
2018

Planar Omnidirectional Crawler Mobile Mechanism - Development of Actual Mechanical Prototype and Basic Experiments

Kenjiro Tadakuma, Eri Takane, Masahiro Fujita, Akito Nomura, Hirone Komatsu, Masashi Konyo +1
RA-L 2018

This letter proposes a planar omnidirectional crawler mobile mechanism. This mechanism is the basis for the mobility of search and rescue robots. A planar omnidirectional crawler aims to facilitate penetration into a narrow path and soft or fragile ground. In this letter, the effectiveness of the pr

Cited by 17Source ↗Scholar ↗
2017

A self-locking-type expansion mechanism to achieve high holding force and pipe-passing capability for a pneumatic in-pipe robot

Tomonari Yamamoto, Masashi Konyo, Kenjiro Tadakuma, Satoshi Tadokoro
ICRA 2017poster

This study proposes a self-locking-type expansion mechanism for in-pipe robots. Previously, we proposed a highspeed locomotion mechanism using pneumatic hollow-shaft actuators; however, this mechanism lacked holding force and could not pass through a bent pipe. The proposed mechanism generates a lar…

Cited by 6Source ↗Scholar ↗
2017

UAV with two passive rotating hemispherical shells for physical interaction and power tethering in a complex environment

Carl John Salaan, Kenjiro Tadakuma, Yoshito Okada, Eri Takane, Kazunori Ohno, Satoshi Tadokoro
ICRA 2017poster

For the past few years, unmanned aerial vehicles (UAVs) have been successfully employed in several investigations and exploration tasks such as aerial inspection and manipulations. However, most of these UAVs are limited to open spaces distant from any obstacles because of the high risk of falling a…

Cited by 32Source ↗Scholar ↗
2016

Development of a spherical tether-handling device with a coupled differential mechanism for tethered teleoperated robots

Tomoya Ichimura, Kenjiro Tadakuma, Eri Takane, Masashi Konyo, Satoshi Tadokoro
IROS 2016poster

Tethered robots often experience entangling of their cables with obstacles in uncertain disaster environments. This paper proposes a spherical tether handling device that unfastens a robot's tether during surveys by releasing the tether and carrying it aside. By using a differential mechanism, the d…

Cited by 4Source ↗Scholar ↗