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The non-destructive inspection of large concrete walls is still an unsolved problem. One possible technique is to use driven wheels for the propulsion and a vacuum system for the adhesion. The seals for the vacuum chambers are slipping over the rough surface, therefore it is not guaranteed that the chambers are always airproof. Especially over concrete walls a special seal construction must be found to make the adhesion more safe. On the other side the propulsion system must be able to produce enough force for carrying and accelerating the robot to a suitable velocity.

This paper will present the climbing robot CROMSCI which uses the described techniques. The propulsion system consists of three omni directional driven wheels which are airproof and completely rotatable and has been presented in earlier papers before. For adhesion a vacuum system of seven controllable vacuum chambers and one reservoir chamber is used. This system including chambers and seals will be discussed in more detail. The rough and sharp-edged surface of concrete walls cause strong requirements to the sealing concerning leak tightness and attrition. Therefore, each sealing must be flexible to allow a good adaption to the ground but also let the robot slip when the wheels are turning.

The non-destructive inspection of large concrete walls via robotic systems is no longer an unsolved problem. This paper will present first results with the climbing prototype CROMSCI which uses a vacuum system of seven controllable vacuum chambers and an omnidirectional drive to move and cling to vertical concrete surfaces. This platform is able to move and inspect vertical surfaces safely, fast and cost-efficient. The technician can check the building more safe without any telescopic crane or other complex access devices via remote control or semi-autonomously.

In this paper, we design a 3DOF climbing robot in the software SolidWorks, and build the positive kinematics equation by the DH method; we use the csape function planted in the MATLAB to compute the curve of the robot’s gait which is appropriate. Then, we import the simplified model to the ADAMS software. After exerting constraints and drives, we get the simulation of the robot’s motion. We also define some markers to measure the angle, which can help us get the inverse kinematic solutions. Through fitting the curve in the MATLAB and the simulation in the ADAMS, we get the comfortable trajectory of the robot and the inverse kinematic solutions of the robot.

This paper describes a compact climbing robot called Cubic-Climber which is driven by two differentially driven magnetic wheels. It is intended for the inspection of the inner surface of confined steel structures which are commonly found in oil rig. It can also be used to carry a welding torch to weld the inner seams of these structures. The Cubic-Climber can turn on the spot and achieve surface transition in the confined steel structures. The magnetic wheel uses wheel-parallel-in-wheel (WpW) structure to achieve surface transition function. The contribution of this paper is the optimization of WpW in terms of the overall weight and required peak motor power through searching the Pareto frontier by genetic algorithm. The experiment results show that the proposed robot is able to achieve a smoother surface transition compared with conventional magnetic wheels.

The paper describes the design of an autonomous wall climbing robot, its control system and stability analysis. Robot sticks to the surface by use of an aerodynamic suction fan.

This paper proposes a glass-wall climbing robot that is intended for cleaning curtain glass wall. It is based on passive suction cups mechanism. The main advantages of the proposed robot are relatively small thickness (which can allow greater payload with a given set of suction cups), easy attachment and detachment, and lower energy consumption. The proposed robot consists of a newly designed guiding rail and eight suction cup systems. The guiding rail has small thickness that results in a portable and compact design. The payload is up to 2 kg. Because the passive suction cups do not need energy input to attach to the glass wall, the proposed robot consumes relatively low energy. A prototype of the robot has been fabricated for evaluation.

Climbing on vertical concrete structures like bridge pylons or dams is still a great challenge for autonomous robots. This paper presents the force- and traction control system of the climbing robot Cromsci which uses a negative pressure system for adhesion and driven wheels for propulsion. Especially in vertical environments the propulsion system must be able to produce enough force for carrying and accelerating the robot contrarily to gravity. Slippery of the wheels must be minimized due to abrasion and uncontrollable movements of the robotic system. This can be done by measuring upcoming forces and taking them into account for a traction control system (TCS). Another problem may occur because of slightly different wheel orientations which will result in increasing shear forces. We will show a control system to minimize these errors and experimental results which demonstrate its functionality.

Large vertical concrete structures are still a great challenge for autonomous climbing robots, which should be able to perform different service tasks like inspection or coating of the rough surface. With the behavior-based obstacle avoidance system of our robot CROMSCI this paper presents a step towards such an autonomous climbing system. Main problems arise from a limited payload for environmental sensor systems. Therefore a special sensor setup and internal representation of the environment has to be found. In this paper we will show the overall structure of our climbing robot CROMSCI using negative pressure adhesion and omnidirectional wheels for locomotion and focus on its sensor systems and the behavior-based components for obstacle avoidance.

This paper aims to develop a multi-body mobile robot which has the capabilities to climb walls and make wall-to-wall transitions. The developed robot consists of three connected bodies, two links, and ten tracked wheels actuated by nine motors. Six vacuum suction pads are installed on each tracked wheel and one additional suction pad is attached to the 2nd body for the steering motion of the entire robot. While each tracked wheel rotates on the vertical plane, the suction pads are automatically activated by the sequential opening of the mechanical valves in pneumatic cylinders, thus enabling the continuous locomotive motion. The kinematics of the proposed mechanism is analytically studied and the capabilities of the robot are experimentally verified in the case of vertical wall climbing and wall-to-wall transition between 90 degree walls. The overall size of the robot is 1000mm × 1600mm × 300 mm with a mass of about 70kg. The maximum climbing speed and carrying payload are 3m/min and 10 kg respectively.

This paper introduces Paraswift, a mobile robot that is able to climb an ordinary wall and deploy a paraglider for a remote controlled return to ground. The goal is entertainment and technical education through an unusual, eye-catching robot. Multiple requirements must be met – to provide a mechanism that generates strong adhesion for climbing yet is low weight for flying, to ensure a reliable transition from climbing to flying, and to handle collision forces on landing – in a single compact robot. The climbing technology is vortex adhesion with wheeled locomotion. The paraglider is folded into the robot shell on ascent and deployed at launch time using a novel mechanism based on a 2-DOF manipulator arm. Flight is remote controlled, and the robot has a protective frame of glass fiber reinforced plastic with a hard foam core to absorb collision forces on landing. This paper describes our work on the complete system, starting with the design, simulation, and physical testing of individual components, and culminating in the integration phase with successful climbing and flying on multiple walls of varying characteristics. We believe that Paraswift is the first demonstration of a compact robot that is capable of vertical climbing and passive flying.

Safe adhesion is a large research area in the field of climbing robots. Many robotic systems use well-known magnetic adhesion or mechanical connections like claws, some others use classic closed-loop controllers in combination with negative pressure adhesion to ensure operation safety. This paper will introduce important safety aspects of the climbing robot CROMSCI which has a negative pressure system, an adaptive inflatable sealing and an omni-directional drive. We will illustrate the novel behavior-based closed-loop controller architecture which has different control levels — starting from individual chamber pressure controllers up to an overall force control. Experimental results will show the performance of the complete behavioral network.

The success and efficiency of wall-climbing robots is not only a question of closed-loop control and electronics. Also materials have a large influence on the operability to make the systems light-weighted or more robust. This paper presents findings based on experiments to find an optimal material for inflatable adaptive sealings. Demands of such sliding sealings are robustness and good sliding characteristics but also fexibility for high sealing performances. The paper gives an overview on several materials and on their characteristics.

Terrain traversability is a common problem in outdoor robotics. The main task is to determine if the current or upcoming terrain can be overcome by the locomotion system of the robot. But, this problem increases in terms of climbing robots which do not only have a locomotion, but also an adhesion system which has to be considered. This paper addresses these aspects and presents an approach to identify and analyze important surface features and to estimate the system’s behavior. Supervised learning techniques are used to classify surfaces into different categories depending on their traversability. As test-platform, a wall-climbing robot using negative pressure adhesion and an omnidirectional drive system is considered which is able to drive on flat concrete buildings.

Designing a magnetic adhesion system for climbing robots requires careful selection of design parameters to achieve a feasible solution. There are many considerations which must be taken into account, such as, size constraints for the intended environment and robot configuration, the maximum load that can be supported by the climbing robot, and the expected air gaps during operation. With consideration of the design challenges, an optimal design for a magnetic adhesion system is presented. Based on the optimal design a prototype footpad has been constructed for use on an inchworm climbing robot and experimental results are presented.

Transition is a desired and critical capability for robots climbing in trusses. In this paper, the issue of transition with a 5-DoFs biped pole-climbing robot between two staggered squared poles in arbitrary relative configuration is addressed and investigated. Two important propositions are first presented and proved. An algorithm based on the analysis is then presented to figure out the optional grasping regions on the current and the target grasping poles. Finally, simulations are conducted to verify and demonstrate the effectiveness of the transition analysis and the proposed algorithm.

Friction of sealings is a general problem for sliding wall-climbing robots using negative pressure adhesion for attraction. Tight sealings are very leak-proof but produce higher friction which has to be overcome by the locomotion system, often in terms of tracks or wheels. On the other hand loose sealings could lead to a fail of adhesion and therefore to a drop-off. This paper presents a method to optimize friction characteristics online depending on the current situation without influencing the attraction forces. The approach makes use of an inflatable and controlled rubber sealing and adjusts the air pressure via an overlaying friction controller. Experiments on the new climbing robot CREA prove the functionality and the benefit of the developed method.

This paper presents an approach to using noisy and incomplete depth-camera datasets to detect reliable surface features for use in map construction for a caterpillar-inspired climbing robot. The approach uses a combination of plane extraction, clustering and template matching techniques to infer from the restricted dataset a usable map. This approach has been tested in both laboratory and real-world steel bridge tunnel datasets generated by a climbing robot, with the results showing that the generated maps are accurate enough for use in localisation and step trajectory planning.