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Magnetic force vs. distance between magnets and plate  

Magnetic force vs. distance between magnets and plate  

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Article
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This paper presents a climbing robot with wheeled locomotion which uses permanent magnets as adhesion mechanism. The robot designed is intended for the inspection of various types of ferromagnetic structures, such as ship hulls, wind turbine towers, bridges, and fuel tanks, in order to detect surface faults or cracks caused by, for example aging or...

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... the magnetic force and the distance from the magnets was also obtained. In order to carry out this analysis, an infinite iron plate with a width of 3mm was added below the magnets. The force applied to the plate was computed for the distances between the magnets and the plate, in the range [0.1,15]mm . The results of this analysis are shown in Fig. 4 As can be seen in Fig. 4, for small distances between the magnets and the plate, the best arrangement corresponds to the magnets oriented with alternating polarities. However, the magnetic force of this arrangement depends greatly on the distance. It is also possible to see that, when all the magnets have the same polarity, the ...
Context 2
... the distance from the magnets was also obtained. In order to carry out this analysis, an infinite iron plate with a width of 3mm was added below the magnets. The force applied to the plate was computed for the distances between the magnets and the plate, in the range [0.1,15]mm . The results of this analysis are shown in Fig. 4 As can be seen in Fig. 4, for small distances between the magnets and the plate, the best arrangement corresponds to the magnets oriented with alternating polarities. However, the magnetic force of this arrangement depends greatly on the distance. It is also possible to see that, when all the magnets have the same polarity, the dependence between the force and ...
Context 3
... previously mentioned, since the distance between the magnets and the wall on the prototype is 7mm, and the maximum height of the weld beads is up to 5mm, the range of operation of the magnets is therefore [2,7]mm. It will be noted in Fig. 4 that the configuration which produces a greater force of attraction in the range of interest is the Halbach array. What is more, and is shown in Fig. 3, the Halbach array augments the magnetic field on one side of the array while cancelling the field to near zero on the other side. This characteristic is an important advantage since ...

Citations

... At the same time, to resist large shear force in the horizontal direction and torque in the vertical direction, it is usually necessary to pad some materials that enhance the coefficient of friction under the magnet. This will weaken the magnetic force instead because the magnetic force decays quickly when the magnet is about to move away from the attracted metal 56 . In addition, if a large permanent magnet is used, in order to control the magnitude of the magnetic force, a lifting mechanism with a large pulling force is required. ...
Article
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Terrestrial self-reconfigurable robot swarms offer adaptable solutions for various tasks. However, most existing swarms are limited to controlled indoor settings, and often compromise stability due to their freeform connections. To address these issues, we present a snail robotic swarm system inspired by land snails, tailored for unstructured environments. Our system also employs a two-mode connection mechanism, drawing from the adhesive capabilities of land snails. The free mode, mirroring a snail’s natural locomotion, leverages magnet-embedded tracks for freeform mobility, thereby enhancing adaptability and efficiency. The strong mode, analogous to a snail’s response to disturbance, employs a vacuum sucker with directional polymer stalks for robust adhesion. By assigning specific functions to each mode, our system achieves a balance between mobility and secure connections. Outdoor experiments demonstrate the capabilities of individual robots and the exceptional synergy within the swarm. This research advances the real-world applications of terrestrial robotic swarms in unstructured environments.
... Most underwater manipulators available for in-situ environments are developed for oil tanker [7] and ship inspection [8], with conventional arm structures generally favoured [9,10]. A unified 6-DoF lightweight robotic arm has been developed for confined spaces by Yin et al. [11], although built-in actuators at the joints ensure the Centre Of Mass (COM) is far from the base, causing significant instability. ...
Article
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Within various unstructured industrial environments, there is often the requirement to conduct remote engineering tasks, such as sampling the structure for analysis prior to decommissioning. Most existing tools are simply not dexterous enough to fulfil this task, and thus new technology is required. We describe here a simple, lightweight, and water-resistant collaborative dual-arm continuum robot system which can aid in this task. To improve the kinematic accuracy of the system, a class of flexible hinges have been combined with a conventional continuum robot configuration. The thickness and width of said flexible hinges can be adjusted to adapt to various tasks. Kinematic and stiffness models have further been developed, incorporating the influence of these flexible hinges. A set of experiments have been conducted to validate the proposed model and demonstrate the advantages of the platform. It was found that the kinematic accuracy of the continuum robot can be improved by a factor of around 10 with the aid of said hinges.
... Permanent magnet adsorption is used for metal walls, which can provide a large adsorption force and does not require external energy consumption. Many types of magnetic wall-climbing robots have been designed and applied, such as magnetic crawler robots [13][14][15][16], climbing robots with magnet-wheeled motion [17][18][19][20][21], omnidirectional climbing robots [22][23][24]. Wall-climbing robots with magnetic adsorption are widely used in the inspection of storage tanks, bridges, and ships. ...
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Automated robot inspection for spherical tank is beneficial to improving work efficiency and reducing costs. This paper presents an inspection robotic system that integrates software and hardware. The designed inspection robot can adsorb and climb on the vertical surface of tanks, carrying some equipment and tools. The mechanical structure of the robot includes four magnetic wheels, two drive components, a vision component and a multi-layer robot frame. Modular magnetic wheels can be installed and replaced quickly and easily. Additional grinding mechanism, cleaning mechanism and detection mechanism are also designed to achieve automated inspection and maintenance. The robotic system software is developed to achieve the remote control and monitoring of the robot. The deep networks of Mask R-CNN are applied to intelligently identify weld seams. Force balance and obstacle-negotiation performance of the robot are analyzed and simulated. Climbing experiments results indicate that the robot can carry 10.1 kg payload and climb stably on the vertical tank wall. In obstacle-surmounting experiments, the robot could smoothly negotiate the weld seam with a height of 4 mm. The robotic system can identify weld seams in real time after training and learning, the identification time of each image is about 0.2-0.25s. The field tests on a 3000 m ³ spherical tank were carried out to test the practicality of the robotic system. The application of this inspection robotic system can effectively improve the automated inspection and maintenance of spherical tanks.
... Chinese Journal of Mechanical Engineering the permanent magnet adsorption robots can adsorb stably but some influencing factors, such as rusts and welds, affect the adsorption capacity and the inspection robot for spherical tanks requires a more flexible and stable structure. There are many forms of permanent magnet wallclimbing robots, such as magnetic-wheels climbing robots [20][21][22][23], crawler climbing robots [24][25][26][27], and omnidirectional-wheels climbing robots [28][29][30][31]. Wallclimbing robots by permanent magnet adsorption can be effectively used in bridges and ships for inspection operations. ...
Article
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Large pressure equipment needs to be tested regularly to ensure safe operation; wall-climbing robots can carry the necessary tools to inspect spherical tanks, such as cameras and non-destructive testing equipment. However, a wall-climbing robot inside a spherical tank cannot be accurately positioned owing to the particularity of the spherical tank structure. This paper proposes a passive support and positioning mechanism fixed in a spherical tank to improve the adsorption capacity and positioning accuracy of the inspection robot. The main body of the mechanism was designed as a truss composed of carbon fiber telescopic rods and can work in spherical tanks with diameters of 4.6‒15.7 m. The structural strength, stiffness, and stability of the mechanism are analyzed via force and deformation simulations. By constructing a mathematical model of the support and positioning mechanism, the influence of structural deformation on the supporting capacity is analyzed and calculated. The robot positioning method based on the support and positioning mechanism can effectively locate the robot inside a spherical tank. Experiments verified the support performance and robot positioning accuracy of the mechanism. This research proposes an auxiliary support and positioning mechanism for a detection robot inside a spherical tank, which can effectively improve the positioning accuracy of the robot and meet the robotic inspection requirements.
... In another case, a magnetic wheeled robot, which can carry magneto resistive sensor array for detecting corrosion and cracks, was developed [11]. Similarly, several climbing permanent magnet-robots [12][13][14][15][16][17][18][19][20] were designed to carry nondestructive evaluation (NDE) devices to detect corrosion, weld defects and cracks, and these robots can be applied for inspecting steel structures and bridges. Other efforts have shown for development of climbing robots for power plant inspection [21] and bridge cable inspection [22]. ...
Article
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As an effort of automating the bridge inspection process, this paper presents a new development of an adaptable tank-like robot, which can climb on steel structures to collect data and perform inspection. While most current steel climbing mobile robots are designed to work on flat steel surface, our proposed tank-like robot design is capable of climbing on different steel structural shapes (e.g., cylinder, cube) by using reciprocating mechanism and magnetic roller-chains. The developed robot can pass through the joints and transition from one surface to the other (e.g., from flat to curving surfaces). A prototype robot integrating multiple sensors (hall-effects, IR, IMU, Eddy current and cameras), has been developed by coping with variety of strict concerns including tight dimension, effective adhesive and climbing adaptation. Rigorous analysis of robot kinematics, adhesive force, sliding and turn-over failure and motor power has been conducted to certify the stability of the proposed design. The theory calculations can serve as an useful framework for designing future steel climbing robots. The cameras and Eddy current sensor is integrated on Robot for visual and in-depth fatigue crack inspection of steel structures. Experimental results and field deployments on more than twenty steel bridges confirm the adhesive, climbing, inspection capability of the robot. Video of this deployment can be seen in this link: https://youtu.be/1Wl9Trd3EoM.
... Each of these designs has its pros and cons. The combining between the adhesion unit (magnets) and the locomotion system (wheels) has mainly two shortcomings [12]: ...
Article
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The tendency of developing wheeled mobile robots in different applications is growing every day. During the past decades, the need for robots capable for climbing vertical wall has been increased. As a result of that, this paper presents a light and low cost wall climbing robot WCR of wheeled locomotion and adopted neodymium magnets to provide adhesion force. This climbing system is intended to be used for educational and research purposes. The mechanical and electrical constructions are presented. The proposed design has the ability to achieve ground-wall transitioning. In order to provide sufficient information about robot mass properties, novel mechanisms to determine the coordinates of the center of mass COM and moment of inertia MOI of the proposed climbing robot have been introduced. In addition, the vision system was suggested to provide feedback signal of robot pose (position and orienting). Finally, to evaluate the performance of the robot design, a prototype was built and tested in the laboratory environment.
... In the oil tank inspection robot [8], the control system includes the embedded computer system, the vision system, the motor driver system, the communication system and the sensing system, and even web based teleoperation for wireless robot commanding can be provided. In the control system of [9], the Atmel ATmega328p microcontroller is used to interface with motors and sensors, an Android phone is utilized to control the robot through the Bluetooth wireless communication and LCD screen is used to get the inspection data from the wireless camera mounted on the robot. ...
Article
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The maintenance of ship hulls involves a series of routine tasks during dry-docking that renews its life-time and operating efficiency. One such task is hull inspection, which is always seen as harmful for human operators and a time-consuming task. The shipping maintenance industries started using the robotic solutions in order to reduce the human risk. However, most of such robotic systems cannot operate fully autonomously due to the fact that it requires humans in the loop. On the other hand, an autonomous hull inspection robot, called Sparrow, is presented in this paper. The proposed robot is capable of navigating autonomously on the vertical metal surface and it could perform metal thickness inspection. This article summarizes the robot’s mechanical design, system control, autonomy, and the inspection module. We evaluated the robot’s performance by conducting experimental trials on three different metal plates that varied in thickness. The results indicate that the presented robot achieves significantly better locomotion while climbing, and it can autonomously measure the metal thickness, which significantly reduces the human efforts in real-time.
... Climbing robots can be used to replace human operators for highly dangerous tasks that require strength, such as cleaning and inspecting high-rise buildings [1,10,20], evaluating and diagnosing storage tanks in nuclear power plants and petrochemical facilities [14,17], and performing welding and maintenance of ship hulls [2,6,9]. In our previous work [21], we designed a wall-climbing robot system based on a rotation-flow adsorption unit that can work on rough walls, and we intend to use this for the task of Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10846-019-01096-w) ...
Article
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Detection of visual markers, such as circular markers or quick response codes, is a commonly used approach to the positioning of wall-climbing robots. However, when the camera is far from the wall-climbing robot (e.g., 20 m), these markers become extremely blurred and difficult to detect. In this paper, a convolutional neural network-based positioning scheme comprised of a global bounding box detector and local wheel detector is proposed. The light-weight local wheel detector can quickly and accurately detect the four wheel points of a distant wall-climbing robot, and the detected wheel points can be used for calculating its position and direction angle. Our wheel detector has a single-frame processing time of 72.2 ms on a CPU and 7.1 ms on a GPU, where the latter meets the real-time positioning requirements of the wall-climbing robot. We also developed an efficient cost function for wheel matching between video frames. Simulation results and multiple test videos confirmed that the proposed cost function can match wheels between video frames perfectly. The high performance of this positioning system indicates that it may be used in a variety of industrial applications.
... Array [8] This copy is strictly for educational purposes and not intended for re-sharing and dissemination a) b) ...
... This technology lends advantages such as: adaptable clamping to a variety of surfaces, low power consumption, resistant to external contamination, and quick, controllable attachment/detachment. San-Millan (2015;Wu et al., 2012) presents three ways with which permanent magnet adhesion can be implemented. The first two involve standard wheels integrated with several cylindrical magnets. ...