Language：Japanese   Publisher：The Robotics Society of Japan  

<p>In a previous study, the authors proposed a method to adapt the dynamic stability of walking, MoS, to walking with a cane. Specifically, the moment of equilibrium (CoP) point between the legs and the cane load was used as the boundary of the BoS. As a result, it was confirmed that the MoS tended to be higher at a specific cane tip position. In this study, a musculoskeletal model was developed for theoretical analysis. The musculoskeletal model consists of four links from the ground to the shoulder, upper arm, forearm, and cane; three joints (shoulder, elbow, and hand); and three muscles (deltoid, triceps, and extensor carpi ulnaris). Using this model, the cane load was estimated for the cane tip position. The results showed that the estimation accuracy was high in the range of 20 to 40 cm. </p>

DOI： 10.7210/jrsj.43.447

CiNii Research

Language：English   Publisher：Fuji Technology Press Ltd.  

<p>T-cane is a primary method used to prevent falls. Although canes effectively increase stability and reduce load, the specific position of the cane tip that maximizes these effects is not yet clear. Furthermore, the cane tip position that enhances effectiveness may also increase the burden on the user. In this study, we used the center of pressure (CoP) as an indicator of stability and shoulder joint adduction torque as an indicator of burden. In this study, we propose a cane tip position that increases the stability of the cane user, but does not increase the burden, through experiment. The experiment involved healthy young male participants. The results confirmed that the CoP increased with the cane tip position. The shoulder joint adduction torque increased with the cane tip position and then remained constant. The results suggest that the participants can walk with higher stability per load when the cane tip was positioned 30 cm in front of the right foot on the ground.</p>

DOI： 10.20965/jrm.2024.p1208

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Scopus

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

<p>It is necessary to reduce the large burden on caregivers pushing wheelchairs. A spring handle has been proposed as a solution to reduce burden on caregiver ’s upper limb. A spring handle consists of a spring built into the handle. By using this handle, the integral value of the pushing force can be reduced at a steady velocity. However, during acceleration, the integral value of the pushing force may become large because of the large contraction of the spring. Therefore, it is considered effective to reduce the burden by increasing the spring constant during acceleration and decreasing it at steady velocity. The objective of this study was to develop a variable stiffness handle that can switch the spring constant between the acceleration and steady velocity sections. Experimental results suggest the effectiveness of the variable stiffness handle.</p>

DOI： 10.1299/jsmermd.2024.2a1-j09

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

<p>As a solution for manpower shortage, soft robot arms that can be used in housekeeping and nursing have been actively developed. A rod-driven soft robot arm that can extend, retract, bend in three dimensions was struggling with a problem of low payload due to tooth skipping of rack gear under high loads. To solve this problem, we devised the new shaped rack gear that can withstand high loads. While the tooth height of the conventional rack gear was 2 mm, we achieved 4 mm tooth height with the new rack gear, keeping the gear tooth size unchanged. The maximum transmission torque without tooth skipping was increased 6.1 times with the new rack gear compared to the conventional rack gear.</p>

DOI： 10.1299/jsmermd.2024.2a1-q03

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

<p>Humans are able to walk by controlling multiple joints simultaneously. In this study, we estimated the impedance of ankle joint with sudden stops of the treadmill belt.We tried to reveal the viscoelastic properties of the lower limb joints considering the interlocking of multiple joints during walking. It was shown that the stiffness of ankle joint has an increasing tendency from 15% to 35% of the walking cycle, and that it can be expected to reach its maximum between 35% to 40% of the walking cycle. We confirmed that the muscle activity level of the gastrocnemius muscle, which is mainly responsible for plantar flexion during walking, roughly corresponds to the phase when the stiffness is expected to be maximum. It was shown that lower limb impedance estimation using sudden stopping of a treadmill is considered to be generally effective in estimating stiffness.</p>

DOI： 10.1299/jsmermd.2024.1p1-f07

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

<p>Snake robots are suitable for work on irregular ground, such as disaster sites with many obstacles, or in areas that are too dangerous or too narrow to enter. In this paper, we developed a snake-shaped robot module that enables smooth bending in three dimensions using crossed links, and reduces the number of motors by using interlocking gears between crossed links. This snake-shaped robot module also has the advantage of being constructed of hard materials and having a high payload. In the first half of this paper we describe the design and mechanics of this new snake-shaped robot module. In the second half of the paper, we describe the stiffness test of this new snake-shaped robot module.</p>

DOI： 10.1299/jsmermd.2024.2a2-n03

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers (IEEE)  

Typically, earthworm-inspired robots consist of N segments and N actuators, each segment having one actuator. However, to reduce the number of actuators, complex mechanisms are often required to activate multiple segments. In this study, we introduce a novel design for an earthworm-inspired robot that reduces the number of actuators from N to N-1, thereby simplifying the mechanical complexity while maintaining high performance. Our proposed robot consists of three segments and two motors embedded between the segments. These two motors share a single flexible shaft and move back and forth along it. By extending or retracting the segments through the movement of the motors, the robot is propelled forward. We evaluated the robot's performance, achieving a maximum speed of 11.6 mm/s, a payload capacity of 200 g (three times its own weight), and a climbing angle of 20 degrees, demonstrating its superior capabilities in various scenarios. The proposed robot generates significant force through simultaneous motor actuation and exhibits effective steering locomotion with additional actuators. This study introduces a new design approach for earthworm-inspired robots and offers valuable insights into achieving locomotion with fewer actuators.

DOI： 10.1109/ACCESS.2024.3445330

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Authorship：Lead author,　Corresponding author  

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Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers (IEEE)  

Pollination is an essential component of plant production, but today, agricultural fields suffer from a shortage of natural pollinators due to a variety of factors. To solve this serious problem, artificial pollination has been introduced. Robotic pollinators not only help farmers with a more cost-effective and stable pollination method but also help in crop production in environments that are not suited for natural pollinators, such as greenhouses. In this paper, we propose a suspended pollination robot that moves along the rail laid on the roof of greenhouses. This robot has a flexible multi-degrees-of-freedom manipulator with two actuators: a retractable linear actuator controls the end effector with a blower to approach the flower, and a tendon-driven continuum actuator changes the orientation of the end effector. After a flower is designated by a perspective camera and close-up camera, the end effector blows the wind to shake the flower. Field tests are conducted by manual control to assess the fruit set rate of tomatoes, one of the well-known self-pollinated plants. This result becomes a benchmark for robotic pollination when manual tasks will be replaced by AI in the future.

DOI： 10.1109/access.2024.3469784

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Language：English   Publisher：Institute of Electrical Electronics Engineers（IEEE）  

Continuum robots can produce dexterous movements and safe interactions due to their inherent compliance, but the lack of stiffness has restricted their deployment in real-world environments. To address this problem, we have studied a high-payload robotic manipulator that bends and extends in 2D space. In this article, we propose the mechanical design for moving our manipulator in 3D space. We use a 3D printer for the prototype production and share its technical strategies for sturdiness and strong fastening.

CiNii Research

Language：English   Publishing type：Research paper (other academic)  

DOI： 10.1109/sii55687.2023.10039169

Repository Public URL： https://hdl.handle.net/2324/7172189

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/lra.2022.3223296

Repository Public URL： https://hdl.handle.net/2324/7172240

Language：English   Publisher：Institute of Electrical Electronics Engineers（IEEE）  

This letter proposes a palm-sized omnidirectional mobile robot with two torus wheels. A single torus wheel is made of an elastic elongated coil spring in which the two ends of the coil connected each other and is driven by a piezoelectric actuator (stator) that can generate 2-degrees-of-freedom (axial and angular) motions. The stator converts its thrust force and torque into longitudinal and meridian motions of the torus wheel, respectively, making the torus work as an omnidirectional wheel on a plane. In this paper, we build a control system of a piezo-driven 2-degrees-of-freedom torus wheel and evaluate its performance measures, such as the transient characteristics, the orientation accuracy and the payload capacity. An omnidirectional robot with the two torus wheels is constructed, and the feedback control for a desired planar motion is demonstrated. The design inspired by a ring torus represents the possibility toward the creation of an unprecedentedly simple, light, and compact 2-wheel omnidirectional robot.

CiNii Research

Language：Others   Publishing type：Research paper (other academic)  

The final goal of this study is to propose a method to increase the sensory feedbacks for the neurorehabilitation of post-stroke patients. As the rehabilitation method for the post-stroke patients, the neurorehabilitation has been studied to reconstruct the neural network. However, in a post-stroke patient, since sensory feedbacks are weakened, the effect of the neurorehabilitation may be reduced. To increase the sensory feedbacks, some studies have tried to use the kinesthetic illusion induced by vibration stimulation on a human body. On the other hand, it is also known that there is a dead time (latency) to generate the kinesthetic illusion. Furthermore, there is an individual variation of the amount of illusion. To use the kinesthetic illusion in the neurorehabilitation, it is necessary to propose a method to shorten the dead time and increase the amount of illusion. In this study, we propose a method to increase the amount of illusion and reduce the dead time by applying electrical stimulation to human muscles in addition to vibration stimulation. To verify the effectiveness of the proposed method, two experiments were carried out. One is the experiment using vibration stimulation only to create the wrist kinesthetic illusion, and the other is using a combination of vibration stimulation and the Functional Electrical Stimulation (FES) to create the illusion. The experimental results showed that the dead time was reduced by 16&#37; and the angular velocity of the illusion (i.e. the amount of illusion) was increased by 250&#37; compared with the only-vibration stimulation condition. These results suggest that the proposed method is useful as a method to increase sensory feedbacks in neurorehabilitation.

DOI： 10.23919/WAC50355.2021.9559448

Language：Others   Publishing type：Research paper (other academic)  

Parallel elastic actuators (PEA) find a growing interest in many research areas ranging from rehabilitation devices to industrial robots on account of their ability to save energy as well as providing passive impact absorption. PEAs are actuators with elements of compliance, such as springs connected in parallel between the actuator and the load. The majority of these PEA mechanisms rely on clutches that require a high amount of power in a short amount of time. Furthermore, these PEA can only switch between a state of complete rigidity to constant stiffness. We consider the emerging design of rigid parallel series elastic actuators (RPSEA) which, in addition to the advantages provided by parallel elastic actuators, uses a motor instead of a clutch-based mechanism to manipulate the stiffness. We develop an experimental setup of the RPSEA and compare an Energy-based control method with a conventional PID control. The response of the two controllers is evaluated under disturbance and presented in this paper.

DOI： 10.23919/WAC50355.2021.9559477

Language：Others   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/access.2021.3062284

Repository Public URL： https://hdl.handle.net/2324/7172163

Language：Others   Publishing type：Research paper (other academic)  

Elastic actuators find a growing interest in many research areas ranging from rehabilitation robotics to industrial robotics. Elastic actuators are actuators with elements of compliance, such as springs connected in different configurations between the actuator and the load. In particular, Rigid Parallel Series Elastic Actuators (RPSEA) is an emerging design that, in addition to the advantages provided by parallel elastic actuators, provides the ability to actively control the storage and release of spring energy. Owing to the spring element in these actuators, they often face the problem of oscillations. In this study, we propose an energy-based control strategy for vibration suppression by using only one motor of the RPSEA. The analytical findings are substantiated with simulations of the mechanism subjected to an impulse disturbance.

DOI： 10.1109/ieeeconf49454.2021.9382723

Language：Others   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/lra.2020.3008118

Language：Others   Publishing type：Research paper (other academic)  

DOI： 10.1109/iros.2018.8594340

Repository Public URL： https://hdl.handle.net/2324/7172166

Language：Others   Publishing type：Research paper (other academic)  

DOI： 10.1109/iros.2017.8206449

Repository Public URL： https://hdl.handle.net/2324/7172187

Language：English   Publishing type：Research paper (scientific journal)  

Study of Rotary-Linear Ultrasonic Motor Output Shafts
We propose output shafts with a preload generation mechanism to improve the output torque and thrust force of the rotary-linear ultrasonic motor. The stator is comprised of a single metallic cube with a through-hole, and the output shafts are inserted into the hole to generate motion in both its circumferential and axial directions arbitrarily. In this paper, two design concepts for optimizing the preload using the output shafts are examined. The first involves a cylinder shaft with micron-order accuracy diameter realization. The cylinder shaft makes contact with the entire inner surface of the stator and generates a preload between the stator and shaft. The second concept employs a spring shaft having a slightly larger diameter than the stator hole, which expands in the radial direction and generates the preload. Experiments show that these design concepts improve the output torque and thrust force.

DOI： 10.20965/ijat.2016.p0549

Repository Public URL： https://hdl.handle.net/2324/7172188

Language：Others   Publishing type：Research paper (other academic)  

DOI： 10.1109/iros.2015.7353483

Repository Public URL： https://hdl.handle.net/2324/7172238

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垂直な壁登るロボット

壁登りロボット次々

壁登り降りするロボット ヒル参考に開発

These soft robots will amaze you

ヒルのごとく壁を縦横に移動

Leech-inspired soft robot can climb walls

Newly-developed tiny wall climbing robot opens up host of possibilities“

Now, a robot that can climb walls

Researchers Develop Leech-Shaped Robot that Climbs Vertical Walls

Robot Leeches Can Climb Over Walls

Robotics Leech-like climbing robot a world first in free movement

Sucker for walls: Soft robot inspired by leeches can grip, climb up walls like a pro

Sucking leech robot scales walls after bathroom revelation

This Soft and Flexible Leech-Inspired Robot Can Climb Walls

This leech-like robot can crawl on walls

This soft and flexible leech-inspired robot can climb walls

Wall-climbing robot inspired by the soft body of a leech

Watch a Leech-Like Robot Crawl Its Way up a Wallt

Leech-inspired robot climbs walls

A Leech-Like Robot Climbs Up the Walls

Inspired By A Soft Body Of A Leech: A Wall-Climbing Robot

Inspired by a Soft Body of a Leech — A Wall-Climbing Robot

Inspired by a soft body of a leech — a wall-climbing robot

Leech inspired wall climbing robot