The Problem of Adhesion Methods and Locomotion Mechanism Development for Wall-Climbing Robots

This review considers a problem in the development of mobile robot adhesion methods with vertical surfaces and the appropriate locomotion mechanism design. The evolution of adhesion methods for wall-climbing robots (based on friction, magnetic forces, air pressure, electrostatic adhesion, molecular forces, rheological properties of fluids and their combinations) and their locomotion principles (wheeled, tracked, walking, sliding framed and hybrid) is studied. Wall-climbing robots are classified according to the applications, adhesion methods and locomotion mechanisms. The advantages and disadvantages of various adhesion methods and locomotion mechanisms are analyzed in terms of mobility, noiselessness, autonomy and energy efficiency. Focus is placed on the physical and technical aspects of the adhesion methods and the possibility of combining adhesion and locomotion methods

Design, Build, and Control of a Climbing Robot for Irregular Surface Geometry

Climbing robots are ideal for situations were maintenance and inspection tasks can cause people to be in dangerous situations or require them to be present for extended periods of time. Applications include inspection, testing, civil construction, cleaning, transport and security. The focus of this thesis was on robots that used pneumatic means to attain adhesion and wheels for locomotion. Research objectives include designing or utilizing a pneumatic based adhesion method to allow the robot to stick to concrete, brick, glass, or other such surfaces; climb on a surface with the lowest possible coefficient of friction between it and the robot; have the ability to overcome a step-like obstacle while climbing; use a single body to passively transition through sharp surface changes while climbing; have the ability to traverse over a gap-type obstacle while climbing without loss of adhesion or mobility. To complete the objectives, a test rig was created that comprised of three surfaces that were hinged together and could be locked into place using aluminum struts at the hinge joint. Different material pallets were created and adhered to plywood that was then mounted to the test rig with screws. The robot was designed and built around laser cut and 3D printed parts. From the experiments it was found that the robot could adhere to a glass surface with a coefficient of friction of 0.43 between it and the glass. Furthermore it was able to overcome a 15mm tall speedbump while climbing without loss of adhesion as well as being able to passively transition between surfaces that had an acute angle of 80° between them and do wall to ceiling transitions. Finally the robot was able to pass over a 55mm gap that was 23mm deep while climbing on a concrete surface. It was concluded that by using thrust based adhesion the robot could handle a diverse array of surfaces and even gain greater ability to overcome obstacles while climbing. Future directions would improve on the robot by adding treads or multiple bodies to improve its base abilities

Design, Build, and Control of a Climbing Robot for Irregular Surface Geometry

Climbing robots are ideal for situations were maintenance and inspection tasks can cause people to be in dangerous situations or require them to be present for extended periods of time. Applications include inspection, testing, civil construction, cleaning, transport and security. The focus of this thesis was on robots that used pneumatic means to attain adhesion and wheels for locomotion. Research objectives include designing or utilizing a pneumatic based adhesion method to allow the robot to stick to concrete, brick, glass, or other such surfaces; climb on a surface with the lowest possible coefficient of friction between it and the robot; have the ability to overcome a step-like obstacle while climbing; use a single body to passively transition through sharp surface changes while climbing; have the ability to traverse over a gap-type obstacle while climbing without loss of adhesion or mobility. To complete the objectives, a test rig was created that comprised of three surfaces that were hinged together and could be locked into place using aluminum struts at the hinge joint. Different material pallets were created and adhered to plywood that was then mounted to the test rig with screws. The robot was designed and built around laser cut and 3D printed parts. From the experiments it was found that the robot could adhere to a glass surface with a coefficient of friction of 0.43 between it and the glass. Furthermore it was able to overcome a 15mm tall speedbump while climbing without loss of adhesion as well as being able to passively transition between surfaces that had an acute angle of 80° between them and do wall to ceiling transitions. Finally the robot was able to pass over a 55mm gap that was 23mm deep while climbing on a concrete surface. It was concluded that by using thrust based adhesion the robot could handle a diverse array of surfaces and even gain greater ability to overcome obstacles while climbing. Future directions would improve on the robot by adding treads or multiple bodies to improve its base abilities

A Survey of Technologies and Applications for Climbing Robots Locomotion and Adhesion

The interest in the development of climbing robots has grown rapidly in the last years. Climbing robots are useful devices that can be adopted in a variety of applications, such as maintenance and inspection in the process and construction industries. These systems are mainly adopted in places where direct access by a human operator is very expensive, because of the need for scaffolding, or very dangerous, due to the presence of an hostile environment. The main motivations are to increase the operation efficiency, by eliminating the costly assembly of scaffolding, or to protect human health and safety in hazardous tasks. Several climbing robots have already been developed, and other are under development, for applications ranging from cleaning to inspection of difficult to reach constructions. A wall climbing robot should not only be light, but also have large payload, so that it may reduce excessive adhesion forces and carry instrumentations during navigation. These machines should be capable of travelling over different types of surfaces, with different inclinations, such as floors, walls, or ceilings, and to walk between such surfaces (Elliot et al. (2006); Sattar et al. (2002)). Furthermore, they should be able of adapting and reconfiguring for various environment conditions and to be self-contained. Up to now, considerable research was devoted to these machines and various types of experimental models were already proposed (according to Chen et al. (2006), over 200 prototypes aimed at such applications had been developed in the world by the year 2006). However, we have to notice that the application of climbing robots is still limited. Apart from a couple successful industrialized products, most are only prototypes and few of them can be found in common use due to unsatisfactory performance in on-site tests (regarding aspects such as their speed, cost and reliability). Chen et al. (2006) present the main design problems affecting the system performance of climbing robots and also suggest solutions to these problems. The major two issues in the design of wall climbing robots are their locomotion and adhesion methods. With respect to the locomotion type, four types are often considered: the crawler, the wheeled, the legged and the propulsion robots. Although the crawler type is able to move relatively faster, it is not adequate to be applied in rough environments. On the other hand, the legged type easily copes with obstacles found in the environment, whereas generally its speed is lower and requires complex control systems. Regarding the adhesion to the surface, the robots should be able to produce a secure gripping force using a light-weight mechanism. The adhesion method is generally classified into four groups: suction force, magnetic, gripping to the surface and thrust force type. Nevertheless, recently new methods for assuring the adhesion, based in biological findings, were proposed. The vacuum type principle is light and easy to control though it presents the problem of supplying compressed air. An alternative, with costs in terms of weight, is the adoption of a vacuum pump. The magnetic type principle implies heavy actuators and is used only for ferromagnetic surfaces. The thrust force type robots make use of the forces developed by thrusters to adhere to the surfaces, but are used in very restricted and specific applications. Bearing these facts in mind, this chapter presents a survey of different applications and technologies adopted for the implementation of climbing robots locomotion and adhesion to surfaces, focusing on the new technologies that are recently being developed to fulfill these objectives. The chapter is organized as follows. Section two presents several applications of climbing robots. Sections three and four present the main locomotion principles, and the main "conventional" technologies for adhering to surfaces, respectively. Section five describes recent biological inspired technologies for robot adhesion to surfaces. Section six introduces several new architectures for climbing robots. Finally, section seven outlines the main conclusions

Study On Various Adhesion Mechanism For A Wall Climbing Robot

A wall-climbing robot has provoked high attention worldwide ever since it was born in 1960’s. The main function of a wall-climbing robot to survey human being in highly hazardous and dangerous working environment. The aim of this study is to design and develop adhesion mechanism for a wall climbing robot that is adaptable to the various wall surface. Study of various adhesion mechanism and the design structure on wall climbing robot is required in order to understand the concept and function of a wall climbing robot. The adhesion mechanism used in this wall climbing robot is pushing mechanism with propeller and magnetic attachment system on wheel design to allow the robot stick and move against the vertical wall surface. High torque motor that controlled by the motor-driven which attach with Arduino UNO is used to cover the friction and gravitational force when the robot is moving. With the aid of the Arduino IDE software, the algorithm is built up and the theoretical result is generated to verify the force needed to support the robot move on the vertical wall surface. However, the robot is able to attach on the vertical surface but unable to move against the vertical surface of the ferromagnetic cupboard. The failure analysis is described as power loss and the thrust force generated not strong enough to support the robot move against the vertical surface. Lastly, the concept of adhesion mechanism is work but there is some improvement that can be considered to improve the stability and performance of wall climbing robot

Design of Autonomous Cleaning Robot

Today, the research is concentrated on designing and developing robots to address the challenges of human life in their everyday activities. The cleaning robots are the class of service robots whose demands are increasing exponentially. Nevertheless, the application of cleaning robots is confined to smaller areas such as homes. Not much autonomous cleaning products are commercialized for big areas such as schools, hospitals, malls, etc. In this thesis, the proof of concept is designed for the autonomous floor-cleaning robot and autonomous board-cleaning robot for schools. A thorough background study is conducted on domestic service robots to understand the technologies involved in these robots. The components of the vacuum cleaner are assembled on a commercial robotic platform. The principles of vacuum cleaning technology and airflow equations are employed for the component selection of the vacuum cleaner. As the autonomous board-cleaning robot acts against gravity, a magnetic adhesion is used to adhere the robot to the classroom board. This system uses a belt drive mechanism to manoeurve. The use of belt drive increases the area of magnetic attraction while the robot is in motion. A semi-systematic approach using patterned path planning techniques for the complete coverage of the working environment is discussed in this thesis. The outcome of this thesis depicts a new and conceptual mechanical design of an autonomous floor-cleaning robot and an autonomous board-cleaning robot. This evidence creates a preliminary design for proof-of-concept for these robots. This proof of concept design is developed from the basic equations of vacuum cleaning technology, airflow and magnetic adhesion. A general overview is discussed for collaborating the two robots. This research provides an extensive initial step to illustrate the development of an autonomous cleaning robot and further validates with quantitative data discussed in the thesis

Design and development of wall climbing robot

This research work presents the design of a robot capable of climbing vertical and rough planes, such as stucco walls. Such a capacity offers imperative non military person and military preferences, for example, observation, perception, look and recover and actually for diversion and amusements. The robot's locomotion is performed using rack and pinion mechanism and adhesion to wall is performed by sticking using suction cups. The detailed design is modelled and fabrication is performed. It utilizes two legs, each with two degrees of freedom. And a central box containing the required mechanisms to perform the locomotion and adhesion is designed to carry any device to perform works on wall. A model of the robot is fabricated in a workshop using general tools. This model show how the mechanisms in the robot will work and how they are assembled together

Design and Development of a Mobile Climbing Robot for Wind Turbine Inspection

Wind turbines (WT) have become an essential renewable energy source as the contribution of WT farms has reached megawatts scale. However, wind turbine blades (WTB) are subjected to failure due to many loading effects such as aerodynamic, gravity and centrifugal loads and operation in harsh environments such as ultraviolet (UV) radiation, ice, hail, temperature variation, dirt, and salt. As a result, the blades suffer different types of damage. Consequently, a periodic inspection process is required to detect and repair defects before a catastrophic failure happens. This thesis presents a literature review of wall climbing robots to identify the most appropriate locomotion and adhesion method to use for a WT climbing machine that can take a large payload of non-destructive testing (NDT) sensors up to a blade and deploy them with scanning arms. A review of wind turbine blade construction, various loading effects on blades and types of damage in blades is followed by a review of the NDT techniques used for inspecting WTB. The above review determines the design requirements to achieve the aim of the current research which is to design a low-cost and reliable mobile robot which will be able to climb the WT tower and subsequently scan the blade surface to perform the inspection using various sensors to identify and classify damages. This robot system should be able to access all the critical areas of the blade structure in a stable and secure way. It should be stable enough to allow the various test sensors to scan the blade structure in the shortest possible time. The thesis describes the development of a tower climbing robot that uses magnetic adhesion to adhere to the WT. As a preliminary study, a simulation model is developed using COMSOL Multiphysics to simulate the magnetic adhesion force while climbing the tower. A test rig is designed and fabricated to measure the magnetic adhesion force experimentally to validate the simulation model. The response surface methodology (RSM) using Box-Behnken design (BBD) is used to design and perform experiments to optimise different independent variables i.e. air gap, the distance between magnets in an array and backplate (yoke) thickness that affect the magnetic adhesion force. A scaled-down prototype magnetic adhesion climbing robot has been designed and constructed for wind turbine blade inspection. The robot is 0.29 m long with two 1.0 m long arms, weighs 10.0 kg and can carry a maximum 2.0 kg payload of NDT sensors. Optimum design of a magnetic adhesion mechanism has been developed for the climbing robot prototype that maximises the magnetic adhesion force. The robot is equipped with two arms that can be extended by one meter to come close to the blade for inspection. Each arm is equipped with a gripper that can hold an inspection tool of weight up to one kilogram. A scaled-down wind turbine has been modelled using SolidWorks and a portion of it constructed to experimentally test the scaled-down climbing robot. To scale up the robot prototype for operation on a normal sized wind turbine, a 100 m tall wind turbine with three 76 m long blades has been modelled and the prototype robot scaled up based on these dimensions. The scaled-up robot is 3.0 m long, weighs 1135 kg and has two 10 m long arms. Static stress analysis and flow simulation have been carried out to check the durability of the scaled-up robot while climbing the wind turbine tower. The procedure for scaling up the adhesion mechanism to achieve equilibrium of the robot has been introduced based on the reaction force concluded from the static stress and flow simulation study. As a result, the maximum payload that each arm can carry has been calculated for both the scaled-down prototype (1 kg) and the scaled-up design (50 kg). This concludes the utility and robustness of the wall climbing robot as a robotic solution for wind turbine blade inspection

Development of a Wall Climbing Robot and Ground Penetrating Radar System for NonDestructive Testing of Vertical Safety Critical Concrete Structures

This research aims to develop a unique adhesion mechanism for wall climbing robot to automate the technology of non-destructive testing (NDT) of large safety critical reinforced concrete structures such as nuclear power plants, bridge columns, dams etc. This research work investigates the effect of key design parameters involved in optimizing the adhesion force achieved from rare earth neodymium magnets. In order to penetrate a nominal concrete cover to achieve magnetic coupling with buried rebar and generate high enough adhesion force by using minimum number of permanent magnets, criteria such as distance between multiple magnets, thickness of flux concentrator are evaluated by implementing finite element analysis (FEA). The proposed adhesion module consists of three N42 grade neodymium magnets arranged in a unique arrangement on a flux concentrator called yoke. The preliminary FEA results suggest that, using two yoke modules with minimum distance between them generate 82 N higher adhesion force compared to a single module system with higher forceto-weight ratio of 4.36. Presence of multiple rebars in a dense mesh setting can assist the adhesion module to concentrate the magnetic flux along separate rebars. This extended concentration area has led to higher adhesion force of 135.73 N as well as enabling the robot to take turns. Results suggest that, having a 50×50 mm rebar meshing can sustain steep robot rotational movement along it’s centre of gravity where the adhesion force can fall as low as 150 N. A small, mobile prototype robot with on-board force sensor is built that exhibited 3600 of manoeuvrability on a 50×50 mm meshed rebars test rig with maximum adhesion force of 108 N at 35 mm air gap. Both experiment and simulationresults prove that the magnetic adhesion mechanism can generate efficient adhesion force for the climbing robot to operate on vertical reinforced concrete structures. In terms of the NDT sensor, an in-depth analysis of the ground penetrating radar (GPR) is carried out to develop a low cost operational laboratory prototype. A one-dimensional numerical framework based on finite difference time domain (FDTD) method is developed to model response behaviour of a GPR. The effects of electrical properties such as dielectric constant, conductivity of the media are evaluated. A Gaussian shaped pulse is used as source which propagates through the 1D array grid, and the pulse interactions at different media interfaces are investigated. A real life application of GPR to detect a buried steel bar in 1 m thick concrete block is modelled, and the results present 100% accurate detection of the steel bar along with measured depth of the concrete cover. The developed framework could be implemented to model multi-layer dielectric blocks with detection capability of various buried objects. Experimental models are built by utilizing a proposed antenna miniaturization technique of dipole antenna with additional radiating arms. The resultant reflection coefficient values indicate a reduction of 55% and 44% in length reduction compared to a conventional 100 MHz and 200 MHz dipole antenna respectively. The GPR transmitting pulse generator features an enhanced tuneable feature to make the GPR system more adaptable to various environmental conditions. The prototype pulse generator circuit can produce pulses with variable width from 750 ps to 10 ns. The final assembled robotic GPR system’s performance is validated by its capability of detecting and localizing an aluminium sheet and a rebar of 12 mm diameter buried under a test rig built of wood to mimic the concrete structure environment. The final calculations reveal a depth error of +0.1 m. However, the key focus of this work is to prove the design concept and the error in measurement can be addressed by utilizing narrower bandwidth pulse that the proposed pulse generator is capable of generating. In general, the proposed robotic GPR system developed in this research proves the concept of feasibility of undertaking inspection procedure on large concrete structures in hazardous environments that may not be accessible to human inspector