A reduced actuation mecanum wheel platform for pipe inspection

This paper focuses on the design, development and assessment of a novel, 2 degrees-of-freedom magnetic pipe inspection robot. It consists of 4 mecanum wheels, with the diagonals functionally coupled and the system rotation constrained by the surface geometry, maintaining full translational mobility with reduced control and actuation requirements. The system uses positional encoding that is decoupled from the transmission system to overcome the main sources of positional/positioning errors when using mecanum wheels. The kinematic and dynamic models of the system are derived and integrated within the controller. The prototype robot is then tested and shown to follow a scan path at 20mm/s within ±1.5mm whilst correcting for gravitational drift and slip events

Cy-mag3D: a simple and miniature climbing robot with advance mobility in ferromagnetic environment

Cy-mag3D is a miniature climbing robot with advanced mobility and magnetic adhesion. It is very compact: a cylindrical shape with 28 mm of diameter and 62 mm of width. Its design is very simple: two wheels, hence two degrees of freedom, and an advanced magnetic circuit. Despite its simplicity, Cy-mag3D has an amazing mobility on ferromagnetic sheets. From an horizontal sheet, it can make transition to almost any intersecting sheet from 10° to 360° - we baptise the last one surface ip. It passes inner and outer straight corners in any almost inclination of the gravity. Cy-mag3D opens new possibilities to use mobile robots for industrial inspection with stringent size limitations, as found in generators. A patent is pending on this system

Magnetic wheels optimization and application to the MagneBike climbing robot

Magnetic wheels are a powerful solution to design inspection climbing robots with excellent mobility. Magnetic wheels optimization based on simulations and the results that were obtained on prototypes are presented. The measured adhesion was doubled between the classic configuration and a novel multilayer one sharing exactly the same four magnets and the same total volume of iron. This know-how is then applied to optimize magnetic wheels for the existing robot called MagneBike. The adhesion force has been multiplied by 2 to 3 times depending on the conditions. Those amazing improvements open new possibilities for miniaturization of climbing robots or payload's increase

Miniature Mobile Systems for Inspection of Ferromagnetic Structures

Power plants require periodical inspections to control their state. To ensure a safe operation, parts that could fail before the next inspection are repaired or replaced, since a forced outage due to a failure can cost up to millions of dollars per day. Non-Destructive Testing (NDT) methods are used to detect different defects that could occur, such as cracks, thinning, corrosion or pitting. Some parts are inspected directly in situ, but may be difficult to access; these can require opening access holes or building scaffoldings. Other parts are disassembled and inspected in workshops, when the required inspection tools cannot be moved. In this thesis, we developed innovative miniature mobile systems able to move within these small and complex installations and inspect them. Bringing sensors to difficult-to-access places using climbing robots can reduce the inspection time and costs, because some dismantling or scaffolding can be eliminated. New miniature sensors can help to inspect complex parts without disassembling them, and reduce the inspection costs, as well. To perform such inspections, miniature mobile systems require a high mobility and keen sensing capabilities. The following approach was used to develop these systems. First, different innovative climbing robots are developed. They use magnetic adhesion, as most structures are made of ferromagnetic steel. Then, vision is embedded in some of the robots. Performing visual inspections becomes thus possible, as well as controlling the robots remotely, without viewing them. Finally, non-visual NDT sensors are developed and embedded in some of the robots, allowing them to detect defects that simple vision cannot detect. Achieving the miniaturization of the developed systems requires strong system integration during these three steps. A set of examples for the different steps has been designed, implemented and tested to illustrate this approach. The Tripillars robots, for instance, use caterpillars, and are able to climb on surfaces of any inclination and to pass inner angles. The Cy-mag3Ds robots use an innovative magnetic wheel concept, and are able to climb on surfaces of any inclination and to pass inner angles, outer angles and surface flips. The Tubulos robots move in tubes of 25 mm diameter at any inclination. All robots embed the required electronics, actuators, sensors and energy to be controlled remotely by the user. Wireless transmission of the commands signals allows the systems to maintain their full mobility without disturbing cables. Integrating Hall sensors near the magnetic systems allows them to measure the adhesion force. This information improves the security of the robots, since when the adhesion force becomes low, the robots can be stopped before they fall. The Tubulo II uses Magnetic Switchable Devices (MSDs) for adhesion. An MSD is composed of a ferromagnetic stator and one or more moving magnets; it has the advantage of requiring only a low force to switch on or off a high adhesion force. MSDs have the advantage of being easy to clean of the magnetic dust that is present in most real environments and that sticks strongly to magnetic systems. As an additional step toward inspection, a camera is embedded on the Cy-mag3D II and the Tubulos. It allows these robots to inspect visually the structures the robots move in, and to control them remotely. The perspective of a climbing robot in an unknown environment is often not enough to give the user a sense of its scale, and to move efficiently in it. A distance sensor is designed and embedded on the Cy-mag3D II, which increases the user's perception of the environment substantially; Finally, an innovative miniature Magnetic Particle Inspection (MPI) system was developed to inspect turbine blades without disassembling them. An MSD is used to perform the required magnetization. The system can automatically inspect a flat surface, performing all the required steps of MPI: magnetize, spray magnetic particles, record images under UV light and demagnetize. Thanks to the strong integration and miniaturization, the system can potentially inspect complex parts such as steam turbines

Chapter 3.4: Wall Climbing Crawlers for Nondestructive Testing

There is a strong international trend that uses robots as a strategic technology for automated inspection and maintenance work in hazardous environments such as in chemical plants and the nuclear power industry [Fukuda, 1990, Roman, 1993, Takehara, 1989]. The main plant components that benefit from automated inspection are long pipelines and the walls of storage or buffer tanks that are inspected either from the outside or the inside. Large benefits in performance and cost savings are possible. For example, an electric utility has reported a saving of five million dollars within eight years on two plants with a capital spend on robotic hardware of two million dollars [Proc. Int. Conf. on Intelligent Robots and Systems, 1993]

Marine Vessel Inspection as a Novel Field for Service Robotics: A Contribution to Systems, Control Methods and Semantic Perception Algorithms.

This cumulative thesis introduces a novel field for service robotics: the inspection of marine vessels using mobile inspection robots. In this thesis, three scientific contributions are provided and experimentally verified in the field of marine inspection, but are not limited to this type of application. The inspection scenario is merely a golden thread to combine the cumulative scientific results presented in this thesis. The first contribution is an adaptive, proprioceptive control approach for hybrid leg-wheel robots, such as the robot ASGUARD described in this thesis. The robot is able to deal with rough terrain and stairs, due to the control concept introduced in this thesis. The proposed system is a suitable platform to move inside the cargo holds of bulk carriers and to deliver visual data from inside the hold. Additionally, the proposed system also has stair climbing abilities, allowing the system to move between different decks. The robot adapts its gait pattern dynamically based on proprioceptive data received from the joint motors and based on the pitch and tilt angle of the robot's body during locomotion. The second major contribution of the thesis is an independent ship inspection system, consisting of a magnetic wall climbing robot for bulkhead inspection, a particle filter based localization method, and a spatial content management system (SCMS) for spatial inspection data representation and organization. The system described in this work was evaluated in several laboratory experiments and field trials on two different marine vessels in close collaboration with ship surveyors. The third scientific contribution of the thesis is a novel approach to structural classification using semantic perception approaches. By these methods, a structured environment can be semantically annotated, based on the spatial relationships between spatial entities and spatial features. This method was verified in the domain of indoor perception (logistics and household environment), for soil sample classification, and for the classification of the structural parts of a marine vessel. The proposed method allows the description of the structural parts of a cargo hold in order to localize the inspection robot or any detected damage. The algorithms proposed in this thesis are based on unorganized 3D point clouds, generated by a LIDAR within a ship's cargo hold. Two different semantic perception methods are proposed in this thesis. One approach is based on probabilistic constraint networks; the second approach is based on Fuzzy Description Logic and spatial reasoning using a spatial ontology about the environment

Parallel Platform-Based Robot for Operation in Active Water Pipes

This thesis presents a novel design for a pipe inspection robot. The main aim of the design has been to allow the robot to operate in a water pipe while it is still in service. Water pipes form a very crucial part of the infrastructure of the world we live in today. Despite their importance, water leakage is a major problem suffered by water companies worldwide, costing them billions of dollars every year. There are a wide variety of different techniques used for leak detection and localisation, but no one method is capable of accurately pinpointing the leak location and severity in all pipe conditions with minimal labour. A survey of existing pipe inspection robots showed that there have been many designs implemented that are capable of navigating the pipeline environment. However, none of these were capable of fully autonomous control in a live water pipe. It was concluded that an autonomous pipe inspection robot capable of working in active pipelines would be of great industrial benefit as it would be able to carry a wide range of sensors directly to the source of the leak with minimal, if any, human intervention. An inchworm robot prototype was constructed based on a Gough-Stewart parallel platform. The robot’s inverse kinematics equations were derived and a simulation model of the robot was constructed. These were verified using a motion capture suite, confirming that they are valid representations of the robot. The simulation was used to determine the robot’s movement limitations and minimum bend radius it could navigate. Several CFD simulations were carried out in order to estimate the maximum fluid force exerted on the robot. It was found that the robot’s design successfully minimised the fluid force such that off-the-shelf actuators had the capability to overcome it. The prototype was successfully tested in both a straight and bent pipe, demonstrating its ability to navigate a dry pipe environment. Overall, the robot prototype served as a successful proof of concept for a design of pipe inspection robot that would be capable of operating in active pipelines

Design of novel adaptive magnetic adhesion mechanism for climbing robots in ferric structures

The work presented in this thesis proposes a novel adaptive magnetic adhesion mechanism that can be implemented in most locomotion mechanisms employed in climbing robots for ferric structures. This novel mechanism has the capability to switch OFF and ON its magnetic adhesion with minimal power consumption, and remain at either state after the excitation is removed. Furthermore, the proposed adhesion mechanism has the ability to adapt the strength of the adhesive force to a desired magnitude. These capabilities make the proposed adhesion mechanism a potential solution in the field of wall climbing robots. The novel contributions of the proposed mechanism include the switching of the adhesive force, selectivity of the adhesive force magnitude; determination of the parameters that have an impact in the final adhesive force. Finally, a final prototype is constructed with customised components and it is subject to a set of simulations and experiments to validate its performance

Coordinated locomotion between robots separated by a surface

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 69-70).This SM thesis presents the design, modeling, and experimental verification of a novel, programmable connection mechanism for robots separated by a-surface. The connector uses electropermanent magnets (EPMs) [5] to establish a continuum of clamping force between the robots, enabling the motion of one robot to slave the other during a variety of maneuvers. The author designs a novel, solid-state EPM arrangement capable of generating up to an estimated 890N of clamping force under environmental load conditions. A relationship between geometric and environmental variables and connection assembly performance is first modeled and subsequently experimentally characterized. By implementing these connectors in a custom manufactured pair of assembly robots, the author demonstrates the connection assembly and magnetizing hardware can be compactly fit within a tetherless robot application. This mechanism provides a repeatable, easily-automated alternative to robotic systems that depend on mechanic means to regulate clamping force [6].by Andrew D. Marchese.S.M