Inspection Robots in Oil and Gas Industry: a Review of Current Solutions and Future Trends <s> 1) Vertical Structure Inspection <s> Climbing robots are being developed for applications ranging from cleaning to inspection of difficult to reach constructions. These machines should be capable of travelling on different types of surfaces (such as floors, walls, ceilings) and to walk between such surfaces. Furthermore, these machines should adapt and reconfigure for various environment conditions and should be self-contained. Regarding the adhesion to the surface, they should be able to produce a secure gripping force using a light-weight mechanism. Bearing these facts in mind, this paper presents a survey of different technologies used for climbing robots adhesion to surfaces. <s> BIB001 </s> Inspection Robots in Oil and Gas Industry: a Review of Current Solutions and Future Trends <s> 1) Vertical Structure Inspection <s> This paper presents the design of a novel robot capable of climbing on vertical and rough surfaces, such as stucco walls. Termed CLIBO (claw inspired robot), the robot can remain in position for a long period of time. Such a capability offers important civilian and military advantages such as surveillance, observation, search and rescue and even for entertainment and games. The robot's kinematics and motion, is a combination between mimicking a technique commonly used in rock climbing using four limbs to climb and a method used by cats to climb on trees with their claws. It uses four legs, each with four-degrees-of-freedom (4-DOF) and specially designed claws attached to each leg that enable it to maneuver itself up the wall and to move in any direction. At the tip of each leg is a gripping device made of 12 fishing hooks and aligned in such a way that each hook can move independently on the wall's surface. This design has the advantage of not requiring a tail-like structure that would press against the surface to balance its weight. A locomotion algorithm was developed to provide the robot with an autonomous capability for climbing along the pre-designed route. The algorithm takes into account the kinematics of the robot and the contact forces applied on the foot pads. In addition, the design provides the robot with the ability to review its gripping strength in order to achieve and maintain a high degree of reliability in its attachment to the wall. An experimental robot was built to validate the model and its motion algorithm. Experiments demonstrate the high reliability of the special gripping device and the efficiency of the motion planning algorithm. <s> BIB002 </s> Inspection Robots in Oil and Gas Industry: a Review of Current Solutions and Future Trends <s> 1) Vertical Structure Inspection <s> This paper presents a climbing robot with wheeled locomotion and adhesion through permanent magnets, developed with the intention of being used in the inspection of different types of man-made ferromagnetic structures, such as towers for wind turbines, fuel storage tanks, and ship hulls. In this paper are presented the main considerations thought for its project, as well as several constructive aspects, among which are detailed its mechanical and electrical construction, the implemented control architecture, and the human-machine interface developed for the manual and automatic control of the vehicle while in operation. Although it can be manually controlled, the vehicle is designed to have a semiautonomous behavior, allowing a remote inspection process controlled by a technician, this way reducing the risks associated with the human inspection of tall structures and ATEX places. The distinguishing characteristic of this robot is its dynamic adjustment system of the permanent magnets in order to assure the machine adhesion to the surfaces, even when crossing slightly irregular and curved surfaces with a large radius. <s> BIB003 </s> Inspection Robots in Oil and Gas Industry: a Review of Current Solutions and Future Trends <s> 1) Vertical Structure Inspection <s> In this paper, a bioinspired mechanism is presented that allows large patches of directional dry adhesives to attain levels of adhesion previously seen only for small samples in precisely aligned tests. The mechanism uses a rigid tile supported by a compliant material and loaded by an inextensible tendon, and is inspired by the tendon system and the fluid-filled sinus in gecko toes. This mechanism permits the adhesive to make full contact with the surface and have uniform loading despite significant errors in alignment. The single-tile mechanism is demonstrated on the StickybotIII robot and the RiSE climbing robot (gross weight 4 kg). A tiled array of these mechanisms is also presented, with a total adhesive area of 100 cm2. This uses a pressurized sac to equalize adhesive forces among the tiles, and exhibits a comparable adhesive pressure and range of loading angles to those of single tiles. These results suggest that the tiled array can be scaled to larger areas and loads. <s> BIB004 </s> Inspection Robots in Oil and Gas Industry: a Review of Current Solutions and Future Trends <s> 1) Vertical Structure Inspection <s> High-rise tasks such as cleaning, painting, inspection, and maintenance on walls of large buildings or other structures require robots with climbing and manipulating skills. Motivated by these potential applications and inspired by the climbing motion of inchworms, we have developed a biped wall-climbing robot-W-Climbot. Built with a modular approach, the robot consists of five joint modules connected in series and two suction modules mounted at the two ends. With this configuration and biped climbing mode, W-Climbot not only has superior mobility on smooth walls, but also has the function of attaching to and manipulating objects equivalent to a “mobile manipulator.” In this paper, we address several fundamental issues with this novel wall-climbing robot, including system development, analysis of suction force, basic climbing gaits, overcoming obstacles, and transiting among walls. A series of comprehensive and challenging experiments with the robot climbing on walls and performing a manipulation task have been conducted to demonstrate its superior climbing ability and manipulation function. The analytical and experimental results have shown that W-Climbot represents a significant advancement in the development of wall-climbing robots. <s> BIB005
For inspecting the vertical structures, wall climbing robots have gained great interests. The climbing technologies are the main difference between these robots. At the same time, the most important task in the design and development of a climbing robot is to develop an appropriate mechanism to ensure that the robot adheres to different types of walls and surfaces reliably without sacrificing its mobility. According to the adhesion and locomotion principles, the climbing methods can be cauterised as magnetic adhesion mechanism, pneumatic adhesion mechanism and bio-inspired grasping grippers BIB001 , as shown in Fig. 2 . Figure 2 . (a) a magnetic adhesion robot  , (b) a pneumatic adhesion robot  , (c) a cat insperied adhesive robot BIB002 , (d) a gecko inspired robot BIB004 . Vertical structures in the oil and gas company are usually made of carbon steel. Since this kind of material is ferromagnetic, magnetic adhesion can be highly desirable in this kind environment. There is a lot of work utilising magnetic adhesion to inspect these facilities. One method is to use permanent magnets. Such as  , they select strength permanent magnets as the adhesion mechanism, which can hold the robot firmly on the walls. Another advantage of these methods is robots do not need extra power for the adhesion mechanism. In some circumstances, variable adhesion is required and the speed of switching required is high, the electromagnetic adhesion mechanism will become specifically useful BIB003 . Pneumatic adhesion mechanism is another widely used technology in vertical structure inspection robots. The attraction force between the robot and the wall is proportional to the pressure difference between the pressure chamber or suction cups and the atmosphere. Unlike magnetic adhesion methods which can only work on the ferromagnetic surfaces, pneumatic adhesion mechanism is suitable for a wider range of materials. Using suction cups is a very popular method. In BIB005 , three suction cups, a supporting plate, a vacuum pump, and some accessories were used to compose the suction module. The ICM Rover equips vacuum adhesion mechanism as fall protector, while performing inspection tasks  . There is also a variety of works adopting biomimetic adhesion methods to realise the excellent climbing robots. In BIB002 , researchers developed a robot, which consists of four legs with gripping devices made of 12 fishing hooks. This robot can imitate the movement of rock-climbers and the way cats hold surfaces when they climb on vertical direction. A gecko-inspired adhesives method was proposed in BIB004 . Being inspired by the gecko toes, it used a rigid tile supported by a compliant material and loaded by an inextensible tendon. This mechanism allowed the climbing part to make a full contact with the surfaces.