We report memristor behavior in bar shaped single crystals of titania that have been "formed" into electronic conductors. The cycling experiments are carried out with forward and reverse current, rather than...
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Many researchers have been studying long and flexible robots, such as snake-like robots and continuum manipulators. The feature of continuum robots is flexibility; therefore, high rigidity has been considered a charac...
Many researchers have been studying long and flexible robots, such as snake-like robots and continuum manipulators. The feature of continuum robots is flexibility; therefore, high rigidity has been considered a characteristic to be avoided or unavoidably accepted for controllability. We envisioned a continuum manipulator that takes advantage of both high rigidity and flexibility to enhance its abilities. This paper proposes a concept and an integration method of a new long and flexible manipulator, named Robotic Whip, utilizing both flexible motion and tightening by increasing rigidity. The prototype is 1.4 m in length and 647 g in weight and is actuated by three DC motors rotating winches. Pulling wires enable the device to exhibit an active tightening motion, and loosening wires enable a flexible twining motion. In addition, we estimated the flexible motion of the continuum arm, which consisted of 200 originally designed links, using a simulation based on a rigid links model. Through experiments, it was proven that the prototype performance was adequate, and the device twined around the target bar and enhanced its holding ability by tightening the bar to tow a dolly with a mass of above 2 kg. A comparison of the simulation and actual measurement results showed that our model could reduce the number of prototypes by clarifying the device specifications available for a given situation.
Exoskeletons are widely used for both rehabilitation purposes and physiotherapy applications. The continuously increasing elderly population and the number of people needing assistance due to certain illnesses or acci...
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In recent times, there has been growing interest in electric motors, particularly induction motors (IMs), which do not require rare-earth materials. IMs efficiency is a critical parameter as it directly influences the...
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ISBN:
(数字)9798350376067
ISBN:
(纸本)9798350376074
In recent times, there has been growing interest in electric motors, particularly induction motors (IMs), which do not require rare-earth materials. IMs efficiency is a critical parameter as it directly influences the overall efficiency of the system. The iron loss is a significant factor in assessing the overall efficiency of IMs. Therefore, it is crucial to make accurate predictions of iron loss during the design of IMs. Analyzing iron loss of IMs using transient analysis offers accuracy but demands high computational costs due to induced current in the rotor bars and the difference between the stator current frequency and slip frequency. Conversely, utilizing the virtual blocked rotor (VBR) for analysis reduces computational cost but decreases accuracy, because this method can match the stator current frequency and slip frequency. Thus, in this paper, we propose a method aimed at enhancing the accuracy of the VBR while retaining its advantage of lower computational cost compared to conventional transient analysis, utilizing both the VBR and transfer learning. The transfer learning is conducted using a large amount of iron loss excluding slot harmonic components derived from the VBR and a small amount of iron loss including slot harmonic components derived from transient analysis. This method enables accurate determination of iron loss including slot harmonic components with a limited dataset, thereby improving the efficiency of the IMs design process.
This paper focuses on cake topping performed by a soft robotic hands. Recently robots have been introduced into food factories for improving productivity and reducing labor costs. Robots are actively used in various m...
This paper focuses on cake topping performed by a soft robotic hands. Recently robots have been introduced into food factories for improving productivity and reducing labor costs. Robots are actively used in various manufacturing processes. Unfortunately, it is currently difficult to introduce robots into topping, which is a delicate operation dealing with soft food materials. Thus, this research challenges topping operations of cakes using soft robotic hands. We fabricated soft fingers without gluing. Soft fingers were cast in silicone rubber using gelatin as a sacrificial material. A soft robotic hand was composed of a pair of soft fingers. Topping experiments were conducted using the fabricated soft hands. First, we confirmed the usefulness of the soft hands by conducting a topping experiment using strawberry samples. Next, topping experiments were conducted using real strawberries and cake bases. On the ‘nappe’ base with a flat surface, strawberries could be topped straight in a uniform posture. Although the topping was successful on the ‘piping’ base with uneven surface, it was found that the posture of the strawberries varied.
Ferrofluid droplets are of great importance due to their ability to be manipulated by magnetic actuation, enabling progress in various areas, such as nanotechnology, robotics, and optics. Moving, splitting, and mergin...
Ferrofluid droplets are of great importance due to their ability to be manipulated by magnetic actuation, enabling progress in various areas, such as nanotechnology, robotics, and optics. Moving, splitting, and merging the ferrofluid droplets need a comprehensive analysis of the behavior of the ferrofluid droplets in a magnetic field. Here, we analyze the response of ferrofluid droplets when they are under the effect of a uniform rotating magnetic field. A water-based ferrofluid droplet is immersed in a high-viscosity fluid, and the frequency of the applied field is changed from 0.01 to 0.30 Hz for performing experiments. Three distinct types of motion are observed during experiments: pure rotation at a low-frequency magnetic field, splitting the droplet at medium frequency field, and merging the small droplets into one droplet at high frequency. The responses of ferrofluid droplets are explained through the interaction of surface tension, drag, and magnetic force.
Efficient path planning is critical for the safe and effective navigation of Autonomous Aerial Robots (AARs) in complex 3D environments. This paper presents a comprehensive exploration of path planning techniques desi...
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ISBN:
(数字)9798350354133
ISBN:
(纸本)9798350354140
Efficient path planning is critical for the safe and effective navigation of Autonomous Aerial Robots (AARs) in complex 3D environments. This paper presents a comprehensive exploration of path planning techniques designed for AAR operations, with a focus on the application of the D* algorithm and its variants. Beginning with an overview of traditional methods such as Dijkstra's and A* algorithms, this work delves into the advanced capabilities of the D* algorithm family, including dynamic replanning and adaptive optimization for changing environmental conditions. A key contribution of this work is the implementation of these algorithms in a manner that significantly accelerates the search phase, particularly when dealing with multiple robots and goals, enhancing computational efficiency. Through detailed analysis and simulation, this study investigates the practical implementation of these algorithms in 3D space, addressing challenges such as obstacle avoidance, computational efficiency, dynamic feasibility, and real-time adaptability. Our simulated case results demonstrate the efficacy and versatility of these techniques in various AAR missions, providing valuable insights for researchers and practitioners in the field of autonomous aerial navigation. This work not only highlights the strengths and limitations of existing methods but also offers novel solutions to improve the performance of path planning algorithms in dynamic environments.
Many individuals experience knee dysfunctions attributed to the natural aging process and degenerative conditions. To aid individuals in regaining knee functionality, supportive exoskeletons were designed to be affixe...
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ISBN:
(数字)9798350384574
ISBN:
(纸本)9798350384581
Many individuals experience knee dysfunctions attributed to the natural aging process and degenerative conditions. To aid individuals in regaining knee functionality, supportive exoskeletons were designed to be affixed to both the shin and thigh. However, a common issue encountered in knee exoskeletons involves the misalignment of joints between the exoskeleton and the user, resulting in discomfort and potential injuries. To reduce misalignment with the knee joint, it is essential for the thigh and shin harnesses of the exoskeleton to replicate the natural trajectories of the knee. However, achieving this is a complex task due to the shifting center of rotation of the knee in both the Sagittal and Coronal planes. Previous knee exoskeletons primarily focus on aligning the joint in the Sagittal plane, neglecting alignment in the other dimension due to inherent design constraints. For the first time, this study introduces a knee-joint exoskeleton capable of conforming to the natural movement of the knee in both the Sagittal and Coronal planes, with the aim of minimizing joint misalignment without the use of inherently soft materials. A spherical scissor linkage mechanism (SSLM) was utilized in conjunction with a customized guide rail to adjust the center of rotation of the SSLM. This configuration facilitates knee flexion/extension while accommodating the knee joint’s center of rotation in both the Sagittal and Coronal planes. The experimental outcomes demonstrated a substantial reduction in misalignment with the knee when compared to a commercial knee-support brace with a one-degree-of-freedom revolute joint.
This paper presents a bimanual haptic display based on collaborative robot arms. We address the limitations of existing robot arm-based haptic displays by optimizing the setup configuration and implementing inertia/fr...
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