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Rock‐climbing robots have significant potential in fieldwork and planetary exploration. However, they currently face limitations such as a lack of stability and adaptability on extreme terrains, slow locomotion, and single functionality. This study introduces a novel multimodal and adaptive rock‐climbing robot (MARCBot), which addresses these limitations through spiny grippers that draw inspiration from morpho‐functionalities observed in beetles, arboreal birds, and hoofed animals. This hybrid bioinspired design enables high attachment strength, passive adaptability to different terrains, and quick attachment on rock surfaces. The multimodal functionality of the gripper allows for attachment during climbing and support during walking. A novel control strategy using dynamics and quadratic programming (QP) optimizes attachment wrench distribution, reducing cost‐of‐transport by 20.03% and 6.05% compared to closed‐loop inverse kinematic (CLIK) and virtual model control (VMC) methods, respectively. MARCBot achieved climbing speeds of 0.15 m min−1 on a vertical discrete rock surface under gravity and trotting speeds of up to 0.21 m s−1 on various complex terrains. It is the first robot capable of climbing on rock surfaces and trotting in complex terrains without the need for switching end‐effectors. This study highlights significant advancements in climbing and multimodal locomotion for robots in extreme environments. [ABSTRACT FROM AUTHOR]

In this paper, we introduce Tetherbot, a cable-driven climbing robot designed for microgravity environments with sparse holding points, such as space stations or asteroids. Tetherbot consists of a platform with a robotic arm that is suspended via cables from multiple grippers. It achieves climbing locomotion by alternately positioning the platform with the cables and relocating the grippers with the robotic arm from one holding point to the next. The main contribution of this work is the first experimental demonstration of autonomous cable-driven climbing in an environment with sparse holding points. To this end, we outline the design, kinematics, and statics of the Tetherbot and present a path planning algorithm to relocate the grippers. We demonstrate autonomous cable-driven climbing through an experiment conducted in a simulated microgravity environment using the path planning algorithm and a prototype of the robot. The results showcase Tetherbot's ability to achieve autonomous cable-driven climbing locomotion, thereby demonstrating that cable-driven climbing is a viable concept and laying the foundation for future robots of this type. [ABSTRACT FROM AUTHOR]

Snake robots, also known as apodal robots, are among the most common and versatile modular robots. Primarily due to their ability to move in different patterns, they can evolve in scenarios with several constraints, some of them hardly accessible to other robot configurations. This paper deals with a specific environment constraint where the robot needs to climb a prismatic obstacle, similar to a step. The objective is to carry out simulations of this function, before implementing it in the physical model. To this end, we propose two different algorithms, parameterized by the obstacle dimensions determined by image processing, and both are evaluated in simulated experiments. The results show that both algorithms are viable for testing in real robots, although more complex scenarios still need to be further studied. [ABSTRACT FROM AUTHOR]

Abstract Rock‐climbing robots have significant potential in fieldwork and planetary exploration. However, they currently face limitations such as a lack of stability and adaptability on extreme terrains, slow locomotion, and single functionality. This study introduces a novel multimodal and adaptive rock‐climbing robot (MARCBot), which addresses these limitations through spiny grippers that draw inspiration from morpho‐functionalities observed in beetles, arboreal birds, and hoofed animals. This hybrid bioinspired design enables high attachment strength, passive adaptability to different terrains, and quick attachment on rock surfaces. The multimodal functionality of the gripper allows for attachment during climbing and support during walking. A novel control strategy using dynamics and quadratic programming (QP) optimizes attachment wrench distribution, reducing cost‐of‐transport by 20.03% and 6.05% compared to closed‐loop inverse kinematic (CLIK) and virtual model control (VMC) methods, respectively. MARCBot achieved climbing speeds of 0.15 m min−1 on a vertical discrete rock surface under gravity and trotting speeds of up to 0.21 m s−1 on various complex terrains. It is the first robot capable of climbing on rock surfaces and trotting in complex terrains without the need for switching end‐effectors. This study highlights significant advancements in climbing and multimodal locomotion for robots in extreme environments.

Periodic inspections are necessary in maintaining concrete infrastructures. As efficient and low-cost inspection methods, visual inspection robots and hammering inspection robots to detect cracks and internal defects have been developed, respectively. However, these robots can perform only a single task. To realize multiple tasks by a robot, multiple measurement sensors must be installed considering the stability of the robot on the wall and measurement performance. Parameters, such as weight and size, must be considered to ensure the stability of the robot on the wall. We proposed a propeller-type wall-climbing robot that can capture images and perform hammering simultaneously while moving on the wall. The static model of robot was established by considering various parameters, such as the direction of the propeller’s thrust force, weight, and placement of the measurement sensors. This model increases the payload for sensor installation and enables movement on dusty concrete walls with a low friction coefficient. The image captured by the inspection robot was employed for crack detection and width estimation. We confirmed that the hammering sounds generated by the robot showed different frequency characteristics on clear and defective areas. The developed inspection robot can collect adequate data for concrete health monitoring.

This paper introduces an innovative and streamlined design of a robot, resembling a bicycle, created to effectively inspect a wide range of ferromagnetic structures, even those with intricate shapes. The key highlight of this robot lies in its mechanical simplicity coupled with remarkable agility. The locomotion strategy hinges on the arrangement of two magnetic wheels in a configuration akin to a bicycle, augmented by two independent steering actuators. This configuration grants the robot the exceptional ability to move in multiple directions. Moreover, the robot employs a reciprocating mechanism that allows it to alter its shape, thereby surmounting obstacles effortlessly. An inherent trait of the robot is its innate adaptability to uneven and intricate surfaces on steel structures, facilitated by a dynamic joint. To underscore its practicality, the robot's application is demonstrated through the utilization of an ultrasonic sensor for gauging steel thickness, coupled with a pragmatic deployment mechanism. By integrating a defect detection model based on deep learning, the robot showcases its proficiency in automatically identifying and pinpointing areas of rust on steel surfaces. The paper undertakes a thorough analysis, encompassing robot kinematics, adhesive force, potential sliding and turn‐over scenarios, and motor power requirements. These analyses collectively validate the stability and robustness of the proposed design. Notably, the theoretical calculations established in this study serve as a valuable blueprint for developing future robots tailored for climbing steel structures. To enhance its inspection capabilities, the robot is equipped with a camera that employs deep learning algorithms to detect rust visually. The paper substantiates its claims with empirical evidence, sharing results from extensive experiments and real‐world deployments on diverse steel bridges, situated in both Nevada and Georgia. These tests comprehensively affirm the robot's proficiency in adhering to surfaces, navigating challenging terrains, and executing thorough inspections. A comprehensive visual representation of the robot's trials and field deployments is presented in videos accessible at the following links: https://youtu.be/Qdh1oz%5foxiQ and https://youtu.be/vFFq79O49dM. [ABSTRACT FROM AUTHOR]

In this paper, we introduce Tetherbot, a cable-driven climbing robot designed for microgravity environments with sparse holding points, such as space stations or asteroids. Tetherbot consists of a platform with a robotic arm that is suspended via cables from multiple grippers. It achieves climbing locomotion by alternately positioning the platform with the cables and relocating the grippers with the robotic arm from one holding point to the next. The main contribution of this work is the first experimental demonstration of autonomous cable-driven climbing in an environment with sparse holding points. To this end, we outline the design, kinematics, and statics of the Tetherbot and present a path planning algorithm to relocate the grippers. We demonstrate autonomous cable-driven climbing through an experiment conducted in a simulated microgravity environment using the path planning algorithm and a prototype of the robot. The results showcase Tetherbot’s ability to achieve autonomous cable-driven climbing locomotion, thereby demonstrating that cable-driven climbing is a viable concept and laying the foundation for future robots of this type.

Snake robots, also known as apodal robots, are among the most common and versatile modular robots. Primarily due to their ability to move in different patterns, they can evolve in scenarios with several constraints, some of them hardly accessible to other robot configurations. This paper deals with a specific environment constraint where the robot needs to climb a prismatic obstacle, similar to a step. The objective is to carry out simulations of this function, before implementing it in the physical model. To this end, we propose two different algorithms, parameterized by the obstacle dimensions determined by image processing, and both are evaluated in simulated experiments. The results show that both algorithms are viable for testing in real robots, although more complex scenarios still need to be further studied.

To date, scholars have only conducted theoretical research on pipeline robots with cylindrical shapes over bends. However, not all pipeline robots are cylindrical in shape. This paper presents a theoretical investigation of a rectangular pipeline robot’s bending-passing ability using geometric and vector approaches and addresses dimensional limitations. Considering the shortcomings of most existing pipeline robots, such as the limited range of pipe diameters that are allowed, the inability to climb vertical pipes, and the single purpose, this study suggests a multi-functional modular pipeline robot that can support a wide range of pipe diameters. The drive module was constructed as a rectangular structure, which confirmed the accuracy of the bend-through theory. The driving module, as the central component of the pipeline robot, can accommodate pipe diameters ranging from 250 to 450mm. It was demonstrated that it can generate a traction force of approximately 600N, which can be used to drive other working modules.

Aiming at the maintenance of dangerous parts of transmission tower，a new climbing robot is designed. According to the motion environment and clamping mode of the climbing robot，a composite structure combining magnetic adsorption and mechanical clamping is designed to ensure the reliability and accuracy of clamping. The clamping claw is driven by a motor and drives the screw elevator to move up and down through gear transmission，so as to realize the clamping of the claw to the angle steel. At the same time，the electromagnet adsorbs the angle steel to realize the double clamping of the angle steel，which effectively resists the danger of overturning and falling off of the climbing robot on the iron tower. The design process of electromagnetic adsorption clamping gripper is introduced，the three-dimensional model of gripper is established，the static analysis and simulation of gripper are carried out，and its rationality is verified by experiments.

This paper presents the design, fabrication, and control of a quadruped wall-climbing robot. The robot’s kinematics is inspired by lizards, which use trot-gait for the locomotion. The key features of this robot are its pressure-sensitive adhesive (PSA) enabled adhesion and peeling mechanism and the locomotion controller capable of straight and turning motion. We obtained an average vertical climbing speed of 1.35 cm/s without payload and 1.25 cm/s with a payload of 20 gm. Rapid prototyping techniques namely 3D-printing and 2D-LASER cutting are used to fabricate the entire structure of the robot, allowing easy replication of the entire robot in case a swarm of such robots is needed. This paper also reports climbing stability criteria for the developed robot expressed in terms of the pitching moment. We envisage that the developed robot can be deployed in surveillance, reconnaissance, cleaning, and repairing applications.

Firm foot contact is the top priority of climbing robots to avoid catastrophic events, especially when working at height. This study proposes a robust planning and control framework for climbing robots that provides robustness to slippage in unknown environments. The framework includes 1) a center of mass (CoM) trajectory optimization under the estimated contact condition, 2) Kalman filter–like approach for uncertain environment parameter estimation and subsequent CoM trajectory re-planing, and 3) an online weight adaptation approach for whole-body control (WBC) framework that can adjust the ground reaction force (GRF) distribution in real time. Though the friction and adhesion characteristics are often assumed to be known, the presence of several factors that lead to a reduction in adhesion may cause critical problems for climbing robots. To address this issue safely and effectively, this study suggests estimating unknown contact parameters in real time and using the evaluated contact information to optimize climbing motion. Since slippage is a crucial behavior and requires instant recovery, the computation time for motion re-planning is also critical. The proposed CoM trajectory optimization algorithm achieved state-of-art fast computation via trajectory parameterization with several reasonable assumptions and linear algebra tricks. Last, an online weight adaptation approach is presented in the study to stabilize slippery motions within the WBC framework. This can help a robot to manage the slippage at the very last control step by redistributing the desired GRF. In order to verify the effectiveness of our method, we have tested our algorithm and provided benchmarks in simulation using a magnetic-legged climbing robot Manegto.

Geckos use millions of dry bristles on their toes to adhere to and rapidly run up walls and across ceilings. This has inspired the successful development of dry adhesive materials and their application to climbing robots. The tails of geckos also help realize adaptive and robust climbing behavior. Existing climbing robots with gecko-inspired tails have demonstrated improved locomotion performance. However, few studies have focused on the role of a robot’s gecko-inspired tail when climbing a sloped surface and its effects on the overall locomotion performance. Thus, this paper reviews and analyzes the roles of the tails of geckos and robots in terms of their climbing performances and compares the advantages and disadvantages of robots’ tails made of rigid and soft materials. This review could assist roboticists decide whether a tail is required for their robots and which materials and motion types to use for the tail in order to fulfill their desired functions and even allow the robots to adapt to different environments and tasks.

Ensuring the structural integrity of steel construction is critical, necessitating effective methods for detecting bolt defects. Traditional inspection methods are reliable but require significant labor and struggle with the accessibility of complex structures. This research introduces a real-time bolt-defect detection system that integrates tiny machine learning (TinyML) with a magnetic climbing robot to enhance inspection efficiency and scope. The system employs the faster objects, more objects (FOMO) algorithm optimized for edge computing on microcontrollers. This approach enables accurate bolt identification, including normal, loose, and missing bolts. The average system accuracy is 82%, with precision and recall values from 0.57 to 0.89 and 0.67 to 0.87, respectively. The system demonstrates balanced detection, evidenced by an F1 score improvement of up to 62%. The FOMO model displays compelling performance on defect detection tasks, achieving an F1 score of approximately 75%, outperforming the MobileNetV2 Single Shot Multibox Detector with Feature Pyramid Networks Lite and You Only Look Once version 5 small. The efficiency of the FOMO model is highlighted by its low hardware requirements at less than 0.1 MB of flash memory and 893.8 KB of random access memory for the 32-bit floating-point data format and is reduced for the 8-bit integer data format, with inference times of 142 ms and 86 ms, respectively. These findings contrast with the higher resource demands and slower inference time of the compared models, indicating the suitability of the FOMO model for low-capacity microcontrollers and its feasibility for real-time applications. The performance analysis across scenarios confirms the high precision (average 0.77) and recall (average 0.76), validating the robustness of the model in diverse environmental conditions. The system offers an advancement over traditional bolt-defect detection methods in accuracy and efficiency by leveraging TinyML and a magnetic climbing robot, setting new benchmarks for real-time inspection technology. The quantitative results underscore the performance of the system, presenting a scalable, cost-effective solution for improving the safety and durability of steel structures. • TinyML for Inspection - Implementing Tiny Machine Learning for bolt defect detection. • AI-Powered Climbing Robot - A robot with real-time edge AI vision for autonomous inspections. • Implements the FOMO algorithm for precise, fast defect identification on edge devices. • Lightweight, Efficient Design - Energy-efficient system suitable for field use. • Demonstrates robust accuracy and reliability in practical tests. [ABSTRACT FROM AUTHOR]

The MRO industry expected grow is limited by high human injury and death toll rates associated to harsh environments. The maintenance industry plans to integrate robotic systems in the maintenance chain promoting faster procedures with lower risks for humans. The uneven working scenarios ask for flexible solutions able to operate under different environment conditions. The current article deals with the design of a robotic platform for complex MRO setups able to operate over vertical, curved and irregular surfaces while enduring complex tasks. The solution is presented explaining the mechanical design, multibody simulation model and dexterity assessment along with equipment integration. [ABSTRACT FROM AUTHOR]

Live working on power distribution lines is an effective way to improve the reliability of power supply. The aerial lift device with an insulated boom is often used as a platform to carry out live working, which is difficult to carry out in mountainous areas, paddy fields, and other complex environments. At the same time, power distribution live working requires highly skilled operators, and a lot of personal security measures, which is not conducive to the application in some developing countries. We imagine that the solution of the above problem is to use a robot to climb up the pole and complete the live working instead of the operator. In this article we report a low-cost modular biomimetic robot. The structure of the robot is designed to meet the requirements of live working, and the motion mechanism of the robot climbing poles and performing live work is analyzed. The feasibility of the technology is verified through simulation, experiments, and tests. [ABSTRACT FROM AUTHOR]

The article presents a fundamentally new design of an anthropomorphic walking device for a mobile robot. The novelty of the proposed design lies in the fact that each part of the leg of the robot is made in the form of four corrugated pneumatic chambers that are mounted on spherical hinges. This design allows the robot to move in an angular coordinate system, which is typical for humans. A mathematical model of an elastic walking device is proposed and analytical dependences are given for calculating the geometric and strength parameters. The results of mathematical modelling and recommendations for the design of anthropomorphic walking mechanisms are given. The engineering formulas and diagrams for calculating power loads described in the article allow you to create various modifications of walking robots that have the property of adapting to an arbitrary surface topology for moving a mobile robot. The stated research results allow us to expand the technological capabilities of mobile robots.

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: . [ABSTRACT FROM AUTHOR]

This article tackles the challenge of negative pressure adhesion control of a Vortex Robotic (VR) platform, which utilizes a modified Electric Ducted Fan (EDF)-based design for successfully adhering to surfaces of variable curvature. The resulting Vortex Actuation (VA) system is estimated through a switching Autoregressive-Moving-Average with eXternal input (ARMAX) identification, for accurately capturing the throttle to adhesion force relationship throughout its operating range. For safe attachment of the robot on a surface, the critical adhesion is modeled based on the geometrical properties of the robotic platform for providing the required reference forces. Within this work, an explicit controller via the use of a Constraint Finite Time Optimal Control (CFTOC) approach is designed in an offline manner, which results in a lookup table realization that ensures overall system stability in all state transitions. In an effort to further improve the tracking response for arbitrary setup orientations, the adhesion control scheme is extended through a switching EMPC framework. The resulting frameworks are tested through both dynamic simulation and experimental sequences involving: a) adhesion control on a rotating test curved surface and, b) adhesion and locomotion sequences on a water pipe. [ABSTRACT FROM AUTHOR]

There is an acute shortage of human coconut tree climbers to harvest coconuts in India and other developing countries. The consequential diminished availability of skilled tree climbers, to pass along the trade secrets to the succeeding generations, highlights the exigent need for an unmanned coconut-tree-climber as an alternative solution. This article presents Amaran, a novel robotic coconut tree climber and harvester. Amaran is comprised of a harvester with a distinctive robotic arm (RA) and a cutter, which can be attached to a ring-shaped frame that can be fastened to a coconut tree. Amaran can be controlled, through a wireless interface, either by an operator on the ground or via a smartphone-based app. Once dispositioned in the vicinity of the coconut bunch, the cutter is commanded to harvest the coconuts by cutting the stem of the bunch attached to the tree. Verification of the Amaran robot's viability was confirmed by tests conducted on a coconut tree set up in the design lab. Subsequently, the design of the Amaran robot was validated by field tests on a coconut farm. In this article, we discuss the design of the Amaran body and harvester. Amaran's dexterity in climbing and harvesting coconuts can be challenged by height, circumference, and inclination of the tree. Experimental results show that Amaran can successfully climb trees up to 15.2 m tall, circumferences ranging from 0.66 to 0.92 m, and tree trunk inclinations of up to 30°. [ABSTRACT FROM AUTHOR]

Live working on power distribution lines is an effective way to improve the reliability of power supply. The aerial lift device with an insulated boom is often used as a platform to carry out live working, which is difficult to carry out in mountainous areas, paddy fields, and other complex environments. At the same time, power distribution live working requires highly skilled operators, and a lot of personal security measures, which is not conducive to the application in some developing countries. We imagine that the solution of the above problem is to use a robot to climb up the pole and complete the live working instead of the operator. In this article we report a low-cost modular biomimetic robot. The structure of the robot is designed to meet the requirements of live working, and the motion mechanism of the robot climbing poles and performing live work is analyzed. The feasibility of the technology is verified through simulation, experiments, and tests.

Climbing plants have evolved over millions of years and have adapted to unpredictable scenarios in unique ways. These crucial features make plants an outstanding biological model for scientists and engineers. Inspired by the ratchet‐like attachment mechanism of the hook‐climber Galium aparine, a novel micropatterned flexible mechanical interlocker is fabricated using a 3D direct laser lithography technique. The artificial hooks are designed based on a morphometric analysis of natural hooks. They are characterized in terms of pull‐off and shear forces, both in an array and as individual hooks. The microprinted hooks array shows high values of pull‐off forces (up to F⊥ ≈ 0.4 N cm−2) and shear forces (up to F// ≈ 13.8 N cm−2) on several rough surfaces (i.e., abrasive materials, fabrics, and artificial skin tissues). The contact separation forces of individual artificial hooks are estimated when loads with different orientations are applied (up to F ≈ 0.26 N). In addition, a patterned tape with directional microhooks is integrated into a mobile platform to demonstrate its climbing ability on inclined surfaces of up to 45°. This research opens up new opportunities for prototyping the next generation of mechanical interlockers, particularly for soft‐ and microrobotics, the textile industry, and biomedical fields. [ABSTRACT FROM AUTHOR]

Autonomous navigation through unstructured terrains has been most effectively demonstrated by animals, who utilize a large set of locomotive styles to move through their native habitats. While legged robots have recently demonstrated several of these locomotion modalities (such as walking, running, jumping, and climbing vertical walls), motion planners have yet to be able to leverage these unique mobility characteristics. In this article, we outline some of the specific motion planning challenges faced when attempting to plan for legged systems with dynamic gaits, with specific instances of these demonstrated by the dynamic climbing platform TAILS. Using a unique implementation of sampling-based model predictive optimization, we demonstrate the ability to motion plan around obstacles on vertical walls and experimentally demonstrate this on TAILS by navigating through traditionally difficult narrow gap problems. [ABSTRACT FROM AUTHOR]

Robots of arbitrary orientation (Climber Robot) are a new modification of mobile robots. These robots are equipped with means of holding the robot on a surface of arbitrary orientation relative to the horizon of the technological space. The creation of this type of robotics is at the initial stage and is dictated by the need to perform technological operations for monitoring industrial facilities, installation and dismantling of building structures, repair and preventive maintenance of their components. The article proposed three basic principles for the synthesis of walking mobile robots: the accumulation and transformation of energy, the integration of motion drives and the use of a generator of reactive pneumatic thrust. The implementation of these principles helps to reduce the total power of the drives and to increase the reliability of the holding robots on the surface of an arbitrary orientation in the technological space. The results of mathematical modeling of constructive and technological parameters of mobile robots are described. Ref. 18, pic. 7

Summary: This paper presents visual and 3D structure inspection for steel structures and bridges using a developed climbing robot. The robot can move freely on a steel surface, carry sensors, collect data and then send to the ground station in real-time for monitoring as well as further processing. Steel surface image stitching and 3D map building are conducted to provide a current condition of the structure. Also, a computer vision-based method is implemented to detect surface defects on stitched images. The effectiveness of the climbing robot's inspection is tested in multiple circumstances to ensure strong steel adhesion and successful data collection. The detection method was also successfully evaluated on various test images, where steel cracks could be automatically identified, without the requirement of some heuristic reasoning. [ABSTRACT FROM AUTHOR]

• Presents the design and development of novel magnetic grippers for a climbing robot. • Zero Moment Point and friction analyses are applied to avoid detachment and slippage. • Each gripper uses three switchable magnets and offers a holding force of 33 kg. • Each gripper carries removable rubber pads to increase tolerance to slippage. • Stable adhesion to steel vertical surfaces is demonstrated in worst-case scenarios. Steel structures require inspection and maintenance tasks which are too dangerous for human workers, due to the risk of falling from heights. These tasks can be safely performed with the help of inchworm-like climbing robots, which use magnetic grippers to adhere, climb, and explore steel structures. This paper presents the design and implementation of novel magnetic grippers for the HyReCRo robot, which is a biped robot to climb and explore steel structures. Each gripper carries three switchable magnets and three rubber pads to increase friction and prevent slippage, and they are designed in two steps. Firstly, the notion of the Zero Moment Point is applied to guarantee that the grippers will not detach from the structure. Secondly, a static friction analysis is performed, determining the impending motion of the robot on the onset of slippage and the minimum friction coefficient necessary to prevent it. The developed grippers are very compact and offer an adhesion force of 33 kg on 3 mm-thick steel plates, which ensures a firm and stable adhesion to steel structures in all postures, as the experiments demonstrate. [ABSTRACT FROM AUTHOR]