VLDB 2026 Research / reviewers in the wild / expert
Kenjiro Tadakuma
dblp:72/2009
· DBLP profile ↗
53ranked-venue papers
22as first author
12since 2021 · last 2026
0000-0003-2035-0617ORCID · verified
Domains — the database's venue-derived domains; a paper can count in several
Artificial intelligence and machine learning · 50 · 22 first-author · 10 since 2021Systems, architecture and hardware · 50 · 22 first-author · 10 since 2021Applied, interdisciplinary, general and emerging computing · 3 · 2 since 2021
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2026 | Mobile Robot System for Optimal Towing Welding Cables on WallsabstractIn large-scale shipbuilding, welding tasks represent a significant portion of all tasks, requiring automated robot operation. However, current welding robots are not automated for high and narrow spaces because they cannot pull heavy welding cables, causing deviations from the intended path and reducing the welding accuracy. This paper proposes a cable-towing stabilization method considering factors such as the self-weight of multiple vehicles, magnetic adhesion force, and force necessary to hold the cables. The proposed approach integrates welding robots, which perform welding tasks, with towing robots, which alleviate the load imposed by welding cables and wire feeders. Cable-towing on walls requires reducing excessive distances between vehicles, as well as their excessive acceleration, in addition to maintaining the mechanical stability of each vehicle. Therefore, the optimal positions and postures of the towing vehicles are sequentially calculated using an optimization problem. The proposed method was evaluated through simulations and real-world experiments, confirming stable cabletowing on a wall surface of approximately 3 × 1.5 m. The findings of this research enhance the safety and efficiency of managing deformable linear objects with robots, focusing on mechanical safety while expanding the operational range from single-vehicle wall-mounted operations to cooperative multi-vehicle wall-mounted tasks, thereby increasing applicability to various wall-towing scenarios. Kazuya Oguma, Yoshito Okada, Hirokazu Fujimoto, Kenichi Murano, Haruhiko Eto, Kazunori Ohno, Kenjiro Tadakuma, Satoshi Tadokoro |
IEEE Trans Autom. Sci. Eng. | 7 |
| 2024 | Flexible Omnidirectional Driving Gear Mechanism with Adaptation over Arbitrary CurvaturesabstractA 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 human interface and for workspace optimization. In this study, we propose a novel flexible omnidirectional driving gear for supporting flexible displays discussing its design, motion range, repeatability, positional accuracy, and adaptability to any guide surface through magnetic coupling. The experiments showed satisfactory results for positional accuracy and repeatability with adaptability over a wide range of curvatures. Moses Gladson Selvamuthu, Kazuki Abe, Kenjiro Tadakuma, Riichiro Tadakuma |
ICRA | 3 |
| 2024 | A Modular, Tendon Driven Variable Stiffness Manipulator with Internal Routing for Improved Stability and Increased Payload CapacityabstractStability 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, preventing widespread adoption of this technology. To tackle these problems, this work details the design and experimental testing of a modular, tendon driven bead-style continuum manipulator with tunable stiffness. By embedding the ability to independently control the stiffness of distinct sections of the structure, the manipulator can regulate it’s posture under greater loads of up to 1kg at the end-effector, with reference to the flexible state. Likewise, an internal routing scheme vastly improves the stability of the proximal segment when operating the distal segment, reducing deviations by at least 70.11%. Operation is validated when gravity is both tangential and perpendicular to the manipulator backbone, a feature uncommon in previous designs. The findings presented in this work are key to the development of larger scale continuum designs, demonstrating that flexibility and tip stability under loading can co-exist without compromise. Kyle L. Walker, Alix J. Partridge, Hsing-Yu Chen, Rahul R. Ramachandran, Adam A. Stokes, Kenjiro Tadakuma, Lucas Cruz Da Silva, Francesco Giorgio-Serchi |
ICRA | 6 |
| 2024 | Enhanced Omni-Ball: Spherical Omnidirectional Wheel Achieving Passive Rollers with High Load Capacity and Smoothness through an Offset Rotational AxisabstractThis 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 challenging. The mechanism proposed in this study features an offset design, enabling outer support for the wheel. A prototype was developed and its basic motion was experimentally validated. Kenjiro Tadakuma, Seiji Sakiyama, Eri Takane, Riichiro Tadakuma, Satoshi Tadokoro |
IROS | 1 |
| 2024 | Versatile Variable-Stiffness Scooping End-Effector: Tilting-Scooping-Transfer Mechanism for Objects with Various PropertiesabstractTo 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 successful in scooping up and transporting a wide variety of objects and could be applied to high-mix low-volume production systems. In addition, the load testing of the spatula and modeling of objects that can be tilted backwards provided insight into further improvements of the scooping performance of this mechanism. Kenjiro Tadakuma, Kazuki Abe, Masahiro Watanabe, Shoya Shimizu, Satoshi Tadokoro |
IROS | 2 |
| 2023 | A New Design of Multilayered String Jamming Mechanism with Three-Degree-of-FreedomabstractA 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 environment and a rigid state for the transmission of forces. String jamming mechanisms, which comprise many units connected in a bead-like pattern, have received attention for their ability to switch between flexible and rigid states. In this study, we propose a new design of the string jamming mechanism that enhances the maximum stiffness in the rigid state while maintaining a high fitting performance for the environment in the flexible state. We evaluate the fitting of the mechanism to the environment in a qualitative geometric discussion and compare the performance of the mechanism with that of existing string jamming mechanisms. The results of experiments measuring the maximum stiffness show the usefulness of the proposed mechanism from a quantitative point of view. Ryohei Michikawa, Kenjiro Tadakuma, Fumitoshi Matsuno |
IROS | 2 |
| 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 MechanismabstractSoft 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 rigid bodies. Small pieces were sewed on an elastic sheet using Kevlar strings. We conducted some measurements of puncture resistance, elasticity, and descaling resistance of the scale mechanisms. The results indicate that the elasticity of the proposed scale mechanism was just 150% larger than a simple silicone sheet. In addition, approximately 15 N was required for descaling, which is seven times larger than that of the glued scales. There was no puncture even when pricked with a needle. Kenjiro Tadakuma, Masahiro Watanabe, Satoshi Tadokoro |
IROS | 1 |
| 2022 | Anisotropic-Stiffness Belt in Mono wheeled Flexible Track for Rough Terrain LocomotionabstractRescue 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 capability to get over obstacles. In designing the MW - Track, the track stiffness is an essential factor-the flexible track can adapt to the geometry of the obstacles, but the flexibility prevents grousers from anchoring to the environment steadily. If the track has different localized stiffnesses, both the adaptability and the stability might be archived. In this study, we developed an “anisotropic-stiffness track,” exhibiting different stiffness depending on the bending side, and investigated its deformation characteristics and the effects on mobility. The basic deformation characteristics of the track were confirmed by load tests. The effects on mobility were evaluated by step-climbing tests, ditch-crossing tests, and traction measuring with a mobile robot. Yu Ozawa, Masahiro Watanabe, Kenjiro Tadakuma, Satoshi Tadokoro |
IROS | 3 |
| 2022 | Toroidal Origami Monotrack: Mechanism to Realize Smooth Driving and Bending for Closed-Skin-Drive RobotsabstractWe 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 experience unexpected wrinkling and buckles that lead to a large resistance. In this study, we propose an origami bellows structure with multiple rollers that can maintain the skin tension and deal with the cause of large friction between the skin and the body. The origami structure design method is presented, and the bending angle range and required drive force were derived through a theoretical analysis. The validity of the effectiveness of the concept was verified through prototype testing. Masahiro Watanabe, Yuto Kemmotsu, Kenjiro Tadakuma, Kazuki Abe, Masashi Konyo, Satoshi Tadokoro |
IROS | 3 |
| 2021 | HueCode: A Meta-marker Exposing Relative Pose and Additional Information in Different Colored LayersabstractIn 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 perspective information from the first (most recognizable) type of element marker, the second or higher marker can be recognized with a better success rate. An experiment using a HueCode made from an ArUco marker and a QR code showed that the QR code within the HueCode is recognizable at an elevation angle of up to 15°, compared to 25° for a normal QR code. In addition, the versatility of HueCode is demonstrated using two robotic applications. The first is a lightweight estimation of absolute 6-DoF poses for mobile robots in a GNSS-denied environment, and the other is object annotation in two-dimensional image or three-dimensional space without any prior knowledge. The former realized pose estimation with a position error of less than 0.05 m, and the latter enabled annotation of a mirror and a transparent object, which are difficult for other sensors and machine learning to recognize. Yoshito Okada, Daiki Fujikura, Yu Ozawa, Kenjiro Tadakuma, Kazunori Ohno, Satoshi Tadokoro |
ICRA | 4 |
| 2021 | Amplification of Clamping Mechanism Using Internally-Balanced Magnetic UnitabstractMachines 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 magnetic unit (IB Magnet) as a force amplifier, which is a mechanism able to switch attached and detached states of a permanent magnet with an external force considerably smaller than its original attractive force. To realize the bi-parting constitution of fingers, a new compensation method using conical coil springs was designed to provide both precision and miniaturization. Relative to the constitution with a single motored screw, the prototype gripper for proof of concept successfully amplified the grasping force at most to 292.2% assisted by the magnetic attraction, while keeping the increase in power consumption of a DC motor only by 11.8%, making the force-energy efficiency 2.6 times larger. Thus, it was verified that the proposed gripper enables the use of actuators and current supplies that require less power. Tori Shimizu, Kenjiro Tadakuma, Masahiro Watanabe, Eri Takane, Masashi Konyo, Satoshi Tadokoro |
IROS | 2 |
| 2021 | ABENICS: Active Ball Joint Mechanism With Three-DoF Based on Spherical Gear MeshingsabstractThis 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 (MP-gear)] and the superimposition of those interactions by the CS-gear's quadrature spherical tooth structure. One MP-gear constrains two of the three RDoF of the CS-gear. The driving module which drives the MP-gear converts this “constraint” into a “drive” and drives the CS-gear with two RDoF. The CS-gear orthogonally superimposes the interactions caused by two MP-gears to achieve three RDoF driving forces. The principle was revealed by analyzing an equivalent linkage modeled on the mechanism of ABENICS. The linkage also led to the kinematics and torque equations. The theory and physical characteristics of ABENICS were verified in comprehensive and continuous positioning experiments on manufactured prototypes. The flexibility of the actuator placement was also verified in different configurations of the driving modules. The active ball joint, ABENICS can transmit high torque and reliable positioning in three RDoF without an orientation sensor, which applies to robot joints and orientation control mechanisms. Kazuki Abe, Kenjiro Tadakuma, Riichiro Tadakuma |
IEEE Trans. Robotics | 2 |
| 2020 | Internally-Balanced Magnetic Mechanisms Using a Magnetic Spring for Producing a Large Amplified Clamping ForceabstractTo 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 its significant reduction rate with regard to the control force, the IB Magnet has two major problems in its nonlinear spring, which serves the purpose of cancelling out the internal force on the magnet. These problems include the complicated design procedure and the trade-off relationship between balancing the precision and the volume of the mechanism. This paper proposes a principle for a new balancing method for the IB Magnet. This method uses a like-pole pair of magnets as a magnetic spring, whose repulsive force should equal the attractive force of an unlike-pole pair. To verify the proposed principle, a prototype of the IB Magnet was designed using a magnetic spring and verified through experiments such that its reduction rate is comparable to those of conventional IB Magnets. Moreover, a robotic clamp was developed as an application example that contains the proposed IB Magnets as its internal mechanism. Tori Shimizu, Kenjiro Tadakuma, Masahiro Watanabe, Eri Takane, Masashi Konyo, Satoshi Tadokoro |
ICRA | 2 |
| 2020 | Toward Enabling a Hundred Drones to Land in a MinuteabstractCurrently, 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 control for such services. However, regarding the takeoff and landing port of the drones, conventional methods have focused on the landing operation of a single drone, and the continuous landing of multiple drones has not been realized. To address this issue, we propose a completely novel port system, "EAGLES Port," that allows several drones to continuously land and takeoff in a short time. Experiments verified that the landing time efficiency of the proposed port is ideally 7.5 times higher than that of conventional vertical landing systems. Moreover, the system can tolerate 270 mm of horizontal positional error, ±30° of angular error in the drone’s approach (±40° with the proposed gate mechanism), and up to 1.9 m/s of drone’s approach speed. This technology significantly contributes to the scalability of drone usage. Therefore, it is critical for the development of a future drone port for the landing of automated drone swarms. Daiki Fujikura, Kenjiro Tadakuma, Masahiro Watanabe, Yoshito Okada, Kazunori Ohno, Satoshi Tadokoro |
IROS | 2 |
| 2020 | A Bio-inspired Quadruped Robot Exploiting Flexible Shoulder for Stable and Efficient WalkingabstractWhile 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 to reconciling the discrepancy between the forelimbs and hindlimbs for natural walking, the complex body structure makes it difficult to understand the functionality of animal morphology. In this study, we developed a simple robot model that mimics the flexibility of shoulder region in the sagittal plane, and we conducted a two-dimensional simulation. The results suggest that the flexibility of the shoulder contributes to absorbing the different motions between the forelimbs and hindlimbs. Akira Fukuhara, Megu Gunji, Yoichi Masuda, Kenjiro Tadakuma, Akio Ishiguro |
IROS | 4 |
| 2020 | Emergence of Swing-to-Stance Transition from Interlocking Mechanism in Horse HindlimbabstractThe 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 investigated in the field of anatomy, the function related to the emergence of limb trajectory during dynamic walking has not been revealed. To investigate the role of the interlocking mechanism, we developed a robot model imitating the muscle-tendon arrangement and the dynamics of a horse hindlimb. In the walking experiment, the robot autonomously generated a limb trajectory with a smooth transition between the swing phase and the stance phase by simply swinging the hip joint with sinusoidal input. Moreover, we compared the joint angles between successful and failed walking. The compared results indicate that the extension of the fetlock joint after hoof touchdown plays the crucial role in emergence of a function of supporting body. Kazuhiro Miyashita, Yoichi Masuda, Megu Gunji, Akira Fukuhara, Kenjiro Tadakuma, Masato Ishikawa |
IROS | 5 |
| 2019 | Basic Performance of Planar Omnidirectional Crawler during Direction Switching using Disturbance Degree of Ground Evaluation MethodabstractWe 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 performing turning motion, as the target for evaluation. Second, by utilizing the proposed disturbance degree of ground evaluation method, we investigated how the turning and translational motions of the crawler mechanism affected soft ground by measuring the flow of sand on a horizontal surface. It was quantitatively shown that translational motion switched the travel direction with lesser disturbance to the road surface compared to turning motion. We confirmed that ground disturbance could be evaluated during direction switching using the proposed method. Eri Takane, Kenjiro Tadakuma, Tori Shimizu, Sosuke Hayashi, Masahiro Watanabe, Shingo Kagami, Keiji Nagatani, Masashi Konyo, Satoshi Tadokoro |
IROS | 2 |
| 2019 | Task-Space Control of Articulated Mobile Robots With a Soft Gripper for OperationsabstractA task-space method is presented for the control of a head-raising articulated mobile robot, allowing the trajectory tracking of a tip of a gripper located on the head of the robot in various operations, e.g., picking up an object and rotating a valve. If the robot cannot continue moving because it reaches a joint angle limit, the robot moves away from the joint limit and changes posture by switching the allocation of lifted/grounded wheels. An articulated mobile robot with a gripper that can grasp objects using jamming transition was developed, and experiments were conducted to demonstrate the effectiveness of the proposed controller in operations. Motoyasu Tanaka, Kenjiro Tadakuma, Mizuki Nakajima |
IEEE Trans. Robotics | 2 |
| 2018 | Design and Development of Biaxial Active Nozzle with Flexible Flow Channel for Air Floating Active Scope CameraabstractLong 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 biaxial active nozzle which can rotate the air jet direction along a roll and pitch axis in order to control the direction of reaction force and the head motion of a long flexible robot. A major challenge is how to change the air jet direction without a large resistance to the flow, which reduces the reaction force induced by the air jet. We propose a nozzle whose outlet is connected with a flexible air tube. The direction of the air jet is controlled by the smooth shape deformation of the tube. The nozzle should be compact enough to be installed on a thin robot, although the shape deformation of the tube may cause buckling. The flexible tube is modeled and simulated by a multiple link model used to derive the geometric parameters of the nozzle so that the nozzle is compact and the tube does not buckle. Based on the derived parameters, the biaxial active nozzle was developed. A basic performance experiment shows that the nozzle can change the reaction force direction by deforming the tube shape, while the magnitude of the reaction force is almost constant. We integrated the proposed nozzle with a conventional Active Scope Camera (ASC). The range where the robot can look around in a vertical exploration was significantly improved, which was three times larger than the previous ASC whose head was controlled by pneumatic actuators. The rubble field test demonstrates that the integrated ASC could move over rubble (maximum height of 200 mm) and steer the course. Akihiro Ishii, Yuichi Ambe, Yu Yamauchi, Hisato Ando, Masashi Konyo, Kenjiro Tadakuma, Satoshi Tadokoro |
IROS | 6 |
| 2017 | UAV with two passive rotating hemispherical shells for physical interaction and power tethering in a complex environmentabstractFor 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 as a result of an exposed propeller or not enough protection. On the other hand, a UAV with a passive rotating spherical shell can fly over a complex environment but cannot engage in physical interaction and perform power tethering because of the passive rotation of the spherical shell. In this study, we propose a new mechanism that allows physical interaction and power tethering while the UAV is well-protected and has a good flight stability, which enables exploration in a complex environment such as disaster sites. We address the current problem by dividing the whole shell into two separate hemispherical shells that provide a gap unaffected by passive rotation. In this paper, we mainly discuss the concept, general applications, and design of the proposed system. The capabilities of the proposed system for physical interaction and power tethering in a complex space were initially verified through laboratory-based test flights of our experimental prototype. Carl John Salaan, Kenjiro Tadakuma, Yoshito Okada, Eri Takane, Kazunori Ohno, Satoshi Tadokoro |
ICRA | 2 |
| 2017 | A self-locking-type expansion mechanism to achieve high holding force and pipe-passing capability for a pneumatic in-pipe robotabstractThis 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 large holding force and can easily pass through a bent pipe by invoking a self-locking phenomenon. We conceptualize and design the novel expansion mechanism and introduce its associated mathematical model to formulate the holding force and mechanism design. The characteristics and capabilities of the mechanism are elucidated by experiments. From the experimental results, we optimize the applied pressure and the design of the mechanism. The proposed mechanism generates a maximum holding force of 69.7 N, which is 5.2 times higher than that of the previous mechanism, and drastically improves the robot's bent-pipe-passing capability. Finally, the performance of this mechanism is confirmed in a simulated pipe test. In this trial, a robot equipped with the proposed mechanism smoothly and steadily moves through complex pipe configurations, including the vertical and bent pipes. Tomonari Yamamoto, Masashi Konyo, Kenjiro Tadakuma, Satoshi Tadokoro |
ICRA | 3 |
| 2016 | Development of a spherical tether-handling device with a coupled differential mechanism for tethered teleoperated robotsabstractTethered 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 device drives shells and rollers that hold the tether. On flat surfaces, the device moves forward by driving the shells. When the device climbs over steps, the rollers are driven by the differential mechanism to pull the tether automatically. After prototyping the device, we confirm the surmountability of the proposed device against steps. The results show that the device can climb a height 90.9% of its diameter. We also demonstrate a scenario to handle the tether and untangle multiple tangles in an environment with several obstacles. Tomoya Ichimura, Kenjiro Tadakuma, Eri Takane, Masashi Konyo, Satoshi Tadokoro |
IROS | 2 |
| 2014 | Torus omnidirectional driving unit mechanism realized by curved crawler beltsabstractIn this research, omnidirectional crawler unit with the torus configuration is proposed. It is composed of two curved crawler belts whose inner and outer trajectories have the same length. The prototype is designed and developed. The basic motion of the prototype is confirmed experimentally. Kenjiro Tadakuma, Hirohiko Ogata, Riichiro Tadakuma, Jose Berengueres |
ICRA | 1 |
| 2013 | The gear mechanism with passive rollers: The input mechanism to drive the omnidirectional gear and worm gearingabstractWe have been studying an omnidirectional driving gear mechanism that can generate thrusting force in an arbitrary direction on one surface, which may be flat or curved. This omnidirectional gear is driven by spur gears that are perpendicular. When one spur gear rotates to drive the omnidirectional gear, the other slides between the teeth of the omnidirectional gear and vice versa. In this paper, we introduce gears with passive rollers to reduce the frictional resistance with a mechanism including smooth rolling motion of conical or flat passive rollers, which can boost the power transmission efficiency of the omnidirectional driving gear system. We also confirmed another useful function of this gear with passive rollers as a worm wheel to transmit power from a worm gear with higher energy efficiency than an ordinary worm wheel. Riichiro Tadakuma, Kenjiro Tadakuma, Minoru Takagi, Shotaro Onishi, Gaku Matsui, Kyohei Ioka, Yuichi Tsumaki, Mitsuru Higashimori, Makoto Kaneko |
ICRA | 2 |
| 2013 | Adaptations of omnidirectional driving gears to practical purposesabstractThis video shows multiple omnidirectional driving gears to realize smaller size and weight than the ordinary X-Y stages. The examinations of different materials and sizes of the gear teeth to improve the performances of the omnidirectional driving gears are the main progress of this paper from our previous reports [1]. Kenjiro Tadakuma, Riichiro Tadakuma, Minoru Takagi, Kyohei Ioka, Gaku Matsui, Kenichi Komura, Erick Fernando Moya Arimie, Takahiro Akaike, Yuichi Tsumaki |
IROS | 1 |
| 2012 | Robotic finger mechanism equipped omnidirectional driving roller with two active rotational axesabstractThe finger mechanism equiped with omnidirectional driving roller is shown. The omnidirectional driving roller has two active rotational axes at the touching point. The finger mechanism with this roller can manipulate the grasped object with any arbitrary directional axes. Prototype model has been developed and basic motion of the finger has been confirmed though the experiments. Kenjiro Tadakuma, Riichiro Tadakuma, Mitsuru Higashimori, Makoto Kaneko |
ICRA | 1 |
| 2012 | Study on the omnidirectional driving gear mechanismabstractIn this paper, the principles and the actual configurations of the omnidirectional driving gear mechanism that was implemented by the authors were described. The validity of the proposed structure was also confirmed and its basic characteristics understood through experiments using the actual prototypes. Kenjiro Tadakuma, Riichiro Tadakuma, Kyohei Ioka, Takeshi Kudo, Minoru Takagi, Yuichi Tsumaki, Mitsuru Higashimori, Makoto Kaneko |
ICRA | 1 |
| 2012 | Omnidirectional driving gears and their input mechanism with passive rollersabstractAs ordinary dual-axis driving mechanisms in X-Y directions, for example, commercially available X-Y stages with ball screws are familiar. However, such driving mechanisms have two stages, namely both upper and lower linear actuators, the latter of which must generate sufficient thrust to carry large weights, including that of the upper actuator mechanism, which has hampered efforts to achieve suitably fast and smooth driving motion due to the inertial force effect. It is also difficult to achieve a small and slimline driving mechanism with such overlapping two-stage structure. In these ordinary two-stage driving mechanisms, the motion of the X-Y stage can be disturbed by the wires of the upper actuator. In this research, we have considered the abovementioned problems, and propose a new omnidirectional driving gear mechanism that enhances its driving area from the normal X-Y plane to convex and concave curved surfaces respectively, and even various combinations of both. The smoothness of basic omnidirectional motion and effectiveness of the driving method of this proposed omnidirectional driving gear mechanism have been confirmed with several experiments involving our setups. Kenjiro Tadakuma, Riichiro Tadakuma, Kyohei Ioka, Takeshi Kudo, Minoru Takagi, Yuichi Tsumaki, Mitsuru Higashimori, Makoto Kaneko |
IROS | 1 |
| 2012 | Additional manipulating function for limited narrow space with omnidirectional driving gearabstractIn this paper, additional manipulating function for limited narrow space with omnidirectional driving gear was described. The validity and advantage of the proposed function was also confirmed through experiments using the actual prototype of the planar omnidirectional driving gear units for the parallel gripper. Kenjiro Tadakuma, Riichiro Tadakuma, Kyohei Ioka, Takeshi Kudo, Minoru Takagi, Yuichi Tsumaki, Mitsuru Higashimori, Makoto Kaneko |
IROS | 1 |
| 2011 | "Omni-Paddle": Amphibious spherical rotary paddle mechanismabstractThis paper describes a combination mechanism of a wheeground a paddle to realize an effective movement on the border of ground and water. For the conventional mobile mechanisms on water or on ground the combination of the mechanism to the body of the robot separately, and each one can be the interruption to the other in each field. In this research, we propose a hybrid mechanism of a wheeground a paddle as drive mechanism itself to realize an effective movement on the border such as a coast with debris after a disaster like a seismic sea wave or a tanker grounding accident. A prototype robot has been built and basic experiments on its motion have been conducted. Kenjiro Tadakuma, Riichiro Tadakuma, Aiguo Ming, Makoto Shimojo, Mitsuru Higashimori, Makoto Kaneko |
ICRA | 1 |
| 2011 | Dynamic nonprehensile shaping of a thin rheological objectabstractThis paper describes a dynamic nonprehensile manipulation of a deformable object, where the shape of a thin rheological object is dynamically controlled by the combination of the inertial force and the frictional one generated by the plate's rapid motion. We first introduce a one-dimensional viscous model to approximate the object deformation characteristics, focusing on the final shape of the object. Assuming that the plate has two degrees of freedom: a translational motion and a rotational one, we derive two sufficient conditions to deform the object: one to enlarge it and the other to contract it. Then, we show the plate's cyclic motion leading to the object's continuous deformation. Finally, simulation and experimental results are shown in order to verify the proposed method. Tomoyuki Inahara, Mitsuru Higashimori, Kenjiro Tadakuma, Makoto Kaneko |
IROS | 3 |
| 2011 | The mechanism of the linear load-sensitive continuously variable transmission with the spherical driving unitabstractThis paper describes linear load-sensitive continuously variable transmission with the spherical driving unit. This CVT mechanism consists of spherical drive, drive axis, motor housing, fixed bracket and linear sliding plate. It changes the reduction ratio continuously by inclination angle of active rotational axis. Additionally, this linear mechanism has a load-sensitive function by changing inclination of active rotational axis in response to the load. We have developed a linear load-sensitive continuously variable transmission and confirmed the effectiveness of the proposed mechanism. Kenjiro Tadakuma, Riichiro Tadakuma, Kazuki Terada, Aiguo Ming, Makoto Shimojo, Mitsuru Higashimori, Makoto Kaneko |
IROS | 1 |
| 2011 | Active outline shaping of a rheological object based on plastic deformation distributionabstractThis paper discusses a shaping strategy of a rheological object whose deformation characteristic includes both elasticity and plasticity. We first introduce a seven-nodes viscoelastic model for approximating the outline and the dynamic characteristics of the object. Then, we show a shaping method of the object's outline, where the ratio between the object's length in the grasping direction and that in the perpendicular one is controlled by using a parallel jaw gripper. Based on the plastic deformation distribution for the integrated input stress, the proposed method can actively manage the final object's outline. In addition to the contribution on simplifying the gripper's degree of freedom, this method has the advantage that the handling time is drastically reduced, compared with the position based passive method. We finally show the experimental results for confirming the validity of the proposed method. Kayo Yoshimoto, Mitsuru Higashimori, Kenjiro Tadakuma, Makoto Kaneko |
IROS | 3 |
| 2010 | Development of intelligent robot hand using proximity, contact and slip sensingabstractTo achieve the skillful task like the human, many researchers have been working on robot hand. An interaction with vision and tactile information are indispensable for realization of skillful tasks. In the existing research, the method using a camera to get the vision information is often found. But, in the boundary area of a non-contact phase and a contact phase, there are problem that lack of sensor information because the influence of occlusion comes up to surface. We devise to introduce the proximity sensor in this area. And we call the robot hand which is equipped with proximity, tactile and slip sensor “intelligent robot hand”. In this research, we show the constitution example of the intelligent robot hand and propose the method to realize Pick&Place as concrete task. Hiroaki Hasegawa, Yoshitomo Mizoguchi, Kenjiro Tadakuma, Aiguo Ming, Masatoshi Ishikawa, Makoto Shimojo |
ICRA | 3 |
| 2010 | A new stiffness evaluation toward high speed cell sorterabstractCell stiffness could be an index for evaluating its activity. Although various systems measuring cell stiffness have been proposed so far, they are slow for adaptively connecting to cell sorters capable of handling more than 1000 [cells/sec]. This paper proposes a new approach that can indirectly evaluate the cell stiffness by measuring the passing time for a narrow channel. When a cell passes through the channel, it receives a viscous force depending upon how much deformation is exerted on the cell. We show that the stiffness is a function of both the passing time and the initial diameter of cell. We also show that the stiffness is proportional to the passing time and inversely proportional to the initial diameter, under the assumption that the thickness of fluid film is inversely proportional to the normal force. The experimental validation is given together with the basic working principle. Yuki Hirose, Kenjiro Tadakuma, Mitsuru Higashimori, Tatsuo Arai, Makoto Kaneko, Ryo Iitsuka, Yoko Yamanishi, Fumihito Arai |
ICRA | 2 |
| 2010 | High sensitivity initial slip sensor for dexterous graspabstractSlip-detecting tactile sensors are essential for achieving human-like gripping motion with a robot hand. In previous research, we developed a flexible, thin and lightweight slip sensor that exploits the characteristics of pressure conductive rubber. However, using this sensor, it was difficult to distinguish between object slip and a change in the normal force. Therefore, in the present research, we investigated a method for identifying object slip by analyzing the frequency components of the output signal from the sensor. As a result, we found that high-frequency components of 1 kHz or more are included in the complex voltage signal generated by object slip. Therefore, by using this high-frequency component, we developed a simple sensor that distinguished between both contact and initial slip with high sensitivity. Seiichi Teshigawara, Kenjiro Tadakuma, Aiguo Ming, Masatoshi Ishikawa, Makoto Shimojo |
ICRA | 2 |
| 2010 | Empirical based optimal design of Active Strobe ImagerabstractWe discuss an empirical based design of Active Strobe Imager (ASI) that enables us to visualize the dynamic behavior of tissue, even under a high frequency vibration that cannot be followed by the naked eye. A pneumatic actuator imparts a vibration for the target object. By flashing light with slightly different frequency, we can see the dynamics by the naked eye. We discuss an approach for determining a set of optimal parameters of ASI by considering both the uncomfortability sensation due to light flickering, the sharpness of the motion, and the amplitude of the vibration of the object. We also give an example of optimal parameter determination for human skin. Kohei Funai, Kouji Mizoue, Mitsuru Higashimori, Kenjiro Tadakuma, Makoto Kaneko |
IROS | 4 |
| 2010 | Connected tracked robot with offset joint mechanism for multiple configurationsabstractThis paper describes various configurations of two connected unit crawlers. By changing the relative position of the two connected vehicle units, the overall robot comprising such a mechanism can automatically adapt to surface obstacles on the field, including complicated structures such as disaster-generated debris. In addition, we analyzed the effect of axis arrangements in order to simplify the realization of the switching function so as to achieve the four basic configurations. Kenjiro Tadakuma, Chigusa Ohishi, Akira Maruyama, Riichiro Tadakuma, Keiji Nagatani, Kazuya Yoshida, Aiguo Ming, Makoto Shimojo |
IROS | 1 |
| 2010 | Mechanical design of the Wheel-Leg hybrid mobile robot to realize a large wheel diameterabstractIn this paper, a new category of the wheel-leg hybrid robot is presented. The proposed mechanism can compose large wheel diameter compared with the previous hybrid robot to realize a greater ability to climb obstacles. A prototype model of one Wheel-Leg module of the proposed robot mechanism has been developed to illustrate the concept. Actual design and mode changing experiment with a test mechanical module is also presented. Basic movement tests and a test of the basic properties of the rotational fingertip are also shown. The Basic configurations of wheel-leg retractable is considered well. The integrated mode is also described. Kenjiro Tadakuma, Riichiro Tadakuma, Akira Maruyama, Eric Rohmer, Keiji Nagatani, Kazuya Yoshida, Aiguo Ming, Makoto Shimojo, Mitsuru Higashimori, Makoto Kaneko |
IROS | 1 |
| 2009 | Tracked vehicle with circular cross-section to realize sideways motionabstractIn this video, a novel tracked mechanism for sideways motion is presented. The tracked mechanism is of circular cross-section and has active rolling axes at the center of the circles. Conventional tracked mechanisms can support massive loads, but cannot produce sideways motion. Additionally, previous crawler edges sink undesirably on soft ground, particularly when the vehicle body is subject to a sideways tilt. The proposed design solves these drawbacks by adopting a circular cross-section crawler. A prototype has been developed to illustrate the concept. Motion experiments confirm the novel properties of this mechanism: sideways motion and robustness against edge-sink. Motion experiments, with a test vehicle are also presented. Kenjiro Tadakuma, Riichiro Tadakuma, Keiji Nagatani, Kazuya Yoshida, Steven C. Peters, Martin Udengaard, Karl Iagnemma |
ICRA | 1 |
| 2009 | Development of high-sensitivity slip sensor using special characteristics of pressure conductive rubberabstractEven with the eyes closed, humans are able to grip an object with minimal force without such information as the coefficient of friction or the weight. Tactile sensors capable of detecting slippage are necessary for this gripping action to be realized in a robot hand. Heretofore, many slip sensors were developed and produced, but there was not a slip sensor of simple structure practical for installation on fingertips of a robot hand. Therefore, we propose a low-profile/lightweight slip sensor of simple structure. The special properties of pressure conductive rubber are utilized as a detection device in this sensor. In this paper, we discuss the results of trial manufacture and of slip detection property testing of this sensor. Moreover, we will report the results of slip prevention experiments by this prototype slip sensor, and indicate that the pressure conductive rubber is promising as a material of slip sensor. Seiichi Teshigawara, Kenjiro Tadakuma, Aiguo Ming, Masatoshi Ishikawa, Makoto Shimojo |
ICRA | 2 |
| 2009 | Throwable tetrahedral robot with transformation capabilityabstractIn this paper, a tetrahedral mobile robot with central axis for transformation to the flat vehicle is presented. The throwable robot with the function of going into narrow spaces when its in the flat-vehicle mode is explained in detail. A prototype has been developed to illustrate the concept. Motion experiments confirm the novel properties of this mechanism: mode changing function and omnidirectional motion. Basic Motion experiments, with a test vehicle are also presented. Kenjiro Tadakuma, Riichiro Tadakuma, Keiji Nagatani, Kazuya Yoshida, Aiguo Ming, Makoto Shimojo, Karl Iagnemma |
IROS | 1 |
| 2009 | Basic running test of the cylindrical tracked vehicle with sideways mobilityabstractIn this paper, the basic running performance of the cylindrical tracked vehicle with sideways mobility is presented. The crawler mechanism is of circular cross-section and has active rolling axes at the center of the circles. Conventional crawler mechanisms can support massive loads, but cannot produce sideways motion. Additionally, previous crawler edges sink undesirably on soft ground, particularly when the vehicle body is subject to a sideways tilt. The proposed design solves these drawbacks by adopting a circular cross-section crawler. A prototype. Basic motion experiments with confirm the novel properties of this mechanism: sideways motion and robustness against edge-sink. Kenjiro Tadakuma, Riichiro Tadakuma, Keiji Nagatani, Kazuya Yoshida, Aiguo Ming, Makoto Shimojo, Karl Iagnemma |
IROS | 1 |
| 2008 | The experimental study of a precision parallel manipulator with binary actuation: With application to MRI cancer treatmentabstractIn this paper the performance of a high-precision parallel robot manipulator with bistable actuation is experimentally evaluated. The manipulator is for performing prostate cancer biopsy and treatment within the bore of a magnetic resonance imaging (MRI) system. The analysis and simulations have shown that this bistable manipulator is able to perform well with dielectric elastomer actuators that have been shown to be compatible with the high magnetic fields of an MRI. In this work an experimental prototype system was developed and tested. The results show that it provides the precise needle placement required by the medical task. Kenjiro Tadakuma, Lauren M. DeVita, Jean-Sébastien Plante, Shaoze Yan, Steven Dubowsky |
ICRA | 1 |
| 2008 | Crawler vehicle with circular cross-section unit to realize sideways motionabstractIn this paper, a novel crawler mechanism for sideways motion is presented. The crawler mechanism is of circular cross-section and has active rolling axes at the center of the circles. Conventional crawler mechanisms can support massive loads, but cannot produce sideways motion. Additionally, previous crawler edges sink undesirably on soft ground, particularly when the vehicle body is subject to a sideways tilt. The proposed design solves these drawbacks by adopting a circular cross-section crawler. A prototype has been developed to illustrate the concept. Motion experiments confirm the novel properties of this mechanism: sideways motion and robustness against edge-sink. Motion experiments, with a test vehicle are also presented. Kenjiro Tadakuma, Riichiro Tadakuma, Keiji Nagatani, Kazuya Yoshida, Steven C. Peters, Martin Udengaard, Karl Iagnemma |
IROS | 1 |
| 2007 | On the Form and Function of Gecko foot-hair for Wall Mobility (video background)abstractIn this videopaper, we introduce a climbing system inspired by gecko foot that uses magnets instead of Van der Waals interaction to achieve controlled adhesion. Jose Berengueres, Kenjiro Tadakuma, Tatsuaki Kamoi |
ICRA | 2 |
| 2007 | Compliant Distributed Magnetic Adhesion Device for Wall ClimbingabstractWe introduce a distributed compliant device inspired in gecko foot. It consists of a holder and small independent adhesion units on a flexible support. Unlike gecko, that uses Van der Waals force to achieve adhesion, the proposed design can be based on other adhesion phenomena, (for example magnetic or electrostatic force). We evaluate an implementation based on magnets. Key features are: limited surface roughness compliance, efficiency and cost-performance. Jose Berengueres, Kenjiro Tadakuma, Tatsuaki Kamoi, Robert Kratz |
ICRA | 2 |
| 2007 | Development of holonomic omnidirectional Vehicle with "Omni-Ball": spherical wheelsabstractIn this paper, mechanical design of a novel spherical wheel shape for a omni-directional mobile robot is presented. The wheel is used in a omnidirectional mobile robot realizing high step-climbing capability with its hemispherical wheel. Conventional Omniwheels can realize omnidirectional motion, however they have a poor step overcoming ability due to the sub-wheel small size. The proposed desing solves this drawback by means of a 4 wheeled design. “Omni-Ball” is formed by two passive rotational hemispherical wheels and one active rotational axis. An actual prototype model has been developed to illustrate the concept and to perform preliminary motion experiments, through which the basic performance of the Omnidirectional vechicle with this proposed Omni-Ball mechanism was confirmed. An prototype has been developed to illustrate the concept. Motion experiments, with a test vehicle are also presented. Kenjiro Tadakuma, Riichiro Tadakuma, Jose Berengueres |
IROS | 1 |
| 2006 | Magnetic Hair for Wall MobilityabstractWe introduce a climbing system, inspired by gecko foot that uses magnets in place of Van der Waals interaction. This is possible because both forces, except for a scale factor, have similar force-curves. Taking advantage of this fact, we manufactured a hand-size "magnetic" version of a gecko-foot. This allowed us to conduct naked-eye experiments. As a result we identify four shape function relations that might partially explain the design of gecko feet. Additionally, we report experimental data, introduce a quantitative concept to compare climbing systems and show a prototype of magnetic hair Jose Berengueres, Kunio Takahashi, Shigeki Saito, Kenjiro Tadakuma |
IROS | 4 |
| 2006 | "Tri-Star3"; Horizontal Polyarticular Arm Equipped 3-Wheeled Expandable RoverabstractThe expandable-type rover, which retracts in the spaceship and expands after reaching upon landing seems to be effective as the planetary rover. In our laboratory, "Tri-Star3"; a horizontal poly-articulated expandable 3-wheeled planetary rover based on the expandable rover has been developed. Tri-Star3 has just only three wheels and passive joints with braking mechanisms. This rover expands or changes its own shape by the driving force produced by each wheel when the joints are free to rotate. Because of these reasons, this rover is comparatively light-weight is cheap to manufacture and it is easy to operated. Kenjiro Tadakuma, Masatsugu Matsumoto, Shigeo Hirose |
IROS | 1 |
| 2006 | Mechanical Design of Joint Braking and Underactuated Mechanism of "Tri-Star3"; Horizontal Polyarticular Arm Equipped 3-Wheeled Expandable Mobile RobotabstractIn this paper, a horizontal polyarticular expandable 3-wheeled planetary rover "Tri-Star3" is proposed. This expandable rover conjugates compact folded size with high stability on rough terrain. The design of braking mechanism in each arm's joint is explained in detail. Through experiments, we confirmed the effectiveness of: (i) the underactuated braking mechanism with optimal shape cam and (ii) the underactuated motion of the arm-wheel module. By using this the proposed system achieves omnidirectional mobility with light weight Kenjiro Tadakuma, Masatsugu Matsumoto, Shigeo Hirose |
IROS | 1 |
| 2005 | Motions on steps and slopes of omni-directional mobile robot, "VmaxCarrier2"abstract"VmaxCarrier2" is an omni-directional mobile robot with step-climbing capability, which can be used as a compact, quiet, and durable transportation vehicle in cluttered and cramped environments. In this study ,we discuss the step-climbing sequence of this omni-directional mobile robot with step-climbing capability. In addition that, we show some motions on steps and slope of this vehicle. Kenjiro Tadakuma, Riichiro Tadakuma, Shigeo Hirose |
IROS | 1 |
| 2004 | Development of VmaxCarrier2: Omni-directional Mobile Robot with Function of Step-climbingabstract"VmaxCarrier2" is an omni-directional mobile robot with step-climbing capability, which can be used as a compact, quiet, and durable transportation vehicle in cluttered and cramped environments. We have already developed several kinds of omni-directional mobile robots for situations where it is desirable to be able to move in all directions, such as "VUTON" and "VmaxCarrier". To construct an omni-directional mobile robot with a greatly improved capability to climb steps, we developed the Omni-Disc2, a bent pneumatic actuator, and a pneumatic system. These novel components were constructed into a prototype, and through evaluation experiments we have confirmed the improved step climbing capability of VmaxCarrier2. Kenjiro Tadakuma, Shigeo Hirose, Riichiro Tadakuma |
ICRA | 1 |