Amphibious NDT Robots

Oil, petrochemical, and food processing industries worldwide store their raw materials and product in tens of thousands of storage tanks. The tanks are mostly constructed using welded steel plates and therefore subject to corrosion and weld cracking. Testing the structural integrity of these storage tanks with non-destructive testing (NDT) techniques is an expensive and time consuming activity. The walls of a large tank can usually be tested manually (for corrosion thinning and weld defects using ultrasonic techniques) from outside the tank. Access to most areas of a wall is obtained by constructing scaffolding or abseiling down from the top. However, erecting scaffolding is expensive and the inspection is tedious and slow. These costs can be reduced and the inspection speeded up by using climbing robots that deploy ultrasonic probes with scanning arms

Non-Destructive Testing Robots (NDTBOTS) for In-service Storage Tank Inspection

Petrochemical storage tanks are generally inspected when the tank is offline mostly to assess the extent of underside corrosion on the tank floor. Emptying, cleaning and opening a tank for inspection takes many months and is very expensive. Inspection costs can be reduced significantly by inserting robots through manholes on the tank roof to perform non-destructive testing. The challenge is to develop robots that can operate safely in explosive and hazardous environments and measure the thickness of floor plates using ultrasound sensors. This paper reports on the development of a small and inexpensive prototype robot (NDTBOT) which is designed to be intrinsically safe for zone zero operation. The robot “hops” across the floor to make measurements, without any external moving parts. The paper describes the design, experimental testing of the NDTBOT and presents results of steel plate thickness measurements made under water

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

Safeguarding Safety Critical Infrastructure with Mobile Robot Inspectors , Opportunities and Challenges

Safeguarding Critical Infrastructure with Robotic Inspection, Opportunities and Challenges Reliable Non Destructive Testing (NDT) is vital to the integrity, performance management and sustainability of capital assets in safety critical industries such as oil and gas, aerospace, transportation, power generation and off-shore and subsea operations. The talk will explore opportunities to improve the NDT of industrial structures and decrease the cost of inspection by automating the NDT with mobile robots. The challenges of developing mobile wall climbing and submersible robots will be presented that can provide access to test sites on very large vertical structures or structures located in hazardous environments thereby eliminating the large expense of erecting scaffolding or lengthy preparation for rope and platform access before inspection can start. Some of these developments provide the possibility of saving costs by reducing outage times or carrying out the NDT in-service thus preventing expensive outages. The presentation will show climbing and swimming robots developed to detect weld and corrosion defects on ship hulls, floating platforms, mooring chains, petrochemical storage tanks, pressure vessels, concrete structures, wind blades and aircraft wings and fuselage

Keynote: Robotic Non Destructive Testing

This keynote paper aims to highlight the application of mobile robots to perform inspection and non destructive testing (NDT) in industries such as aerospace, large scale fabrication, pipelines, petro-chemical storage and power generation. It describes industrial tasks where regular inspection is essential to ensure the integrity of infrastructure such as storage tanks, pressure vessels, pipelines, aircraft, ships, etc, and to provide managers of capital assets with data to plan outages and to make decisions on the life span of their infrastructure. The development of robot prototypes is described for these industrial tasks. These robots deploy NDT systems by first providing access to large vertical structures or to test sites that are inaccessible to humans. They are designed to reduce outage time, or where possible, carry out the NDT online thus preventing costly outages

Design and Development of Climbing Robotic Systems for Automated Inspection of Steel Structures and Bridges

Steel structures are indispensable parts of modern civilization, with typical civil infrastructures including bridges, wind turbines, electric towers, oil rigs, ships, and submarines, all made of steel. These structures require frequent maintenance to ensure safety and longevity. Steel bridges are the most challenging architectures due totheir complexity and height. Most inspections are conducted manually by professional human inspectors with special devices to inspect visible damages and defects on or inside these structures. However, this procedure is usually highly time-consuming, costly, and risky. Automated solutions are desired to address this problem. However, arduous engineering is delaying progress. A complete system needs to deal with three main problems: (1) locomotive performance for the high complexity of steel bridges, including differential curvatures, transitions between beams, and obstacles; (2) data collection capability, inclusive of visible and invisible damages, in-depth information such as vibration, coat, and material thickness, etc.; and (3) working conditions made up of gust winds. To achieve such a complete system, this dissertation presents novel developments of inspection-climbing robots. Five different robot versions are designed to find the simplest and most effective configuration as well as control manner. Our approach started with (1) a transformable tank-like robot integrated with a haptic device and ii two natural-inspired locomotion, (2) a roller chain-like robot, (3) a hybrid worming mobile robot, (4) a multi-directional bicycle robot, and (5) an omni-directional climbing Robot, identified as the most potential solution for automated steel bridge inspection. For each robotic development, detailed mechanical analysis frameworks are presented. Both lab tests and field deployments of these robotic systems have been conducted to validate the proposed designs

Internal in-service inspection of petrochemical storage tank floors to detect underside corrosion with Non-Destructive Testing Robot

This research develops a new robotics technology for the in-service inspection of floor plates of the majority for the world’s petrochemical storage tanks. The new robotic system aims to decrease inspection cost, reduce human inspector exposure to chemical and hazard environment during the inspection and eliminate tank outage entirely if the floor is found to contain no corrosion. The research focus is on the design and development of a Non-Destructive Testing Robot (NDTBOT) prototype that uses active buoyancy control for its locomotion mechanism and uses NDT ultrasound to measure floor plate thickness as an indication of corrosion thinning. The NDTBOT hops from one location of the floor to another location to make ultrasound thickness measurements of a tank floor, thus avoiding issues of motion on a dirty tank floor (due to oil sludge). Also, a novel radio frequency (RF) data communication system is investigated and developed that can operate while submerged in oil. This system allows control commands to be sent to the NDTBOT by an operator outside the tank and NDT data to be recovered for analysis. To evaluate the performance of the NDTBOT making thickness measurement in the tank, three types of measurement techniques were used. First, the real thickness was measured using a Vernier caliper, the second method used a standard hand-held ultrasonic thickness measurement instrument and finally the in-service inspection thickness measurements were made with the NDTBOT operating in a water tank. The NDTBOT thickness measurements with an immersion ultrasound probe obtained more accurate results than hand-held contact ultrasonic testing. Petrochemical storage tank size varies from 20 to 200 meters in diameter, rapid corrosion inspection in such tanks with a swarm of robots requires that a number of NDTBOTs be deployed inside the tank to perform the NDT. Such deployment needs coordination and control work between the robots to send the NDT data to the NDT inspector. Therefore, an investigation and experimental radio frequency wireless transmission is done in order to compare different radio frequency communication. Simulation with commercial software CADFEKO is used to perform simulation of RF wave transmission in petroleum and vegetable oil with selected radio frequencies of 200 MHz, 300 MHz, and 433 MHz. The experimental work and simulation results give confidence. The RF communication in petroleum medium is feasible for both control of NDTBOTs inside the tank and NDT data transmission back to a technician’s console placed outside the tank

Climbing and Walking Robots

With the advancement of technology, new exciting approaches enable us to render mobile robotic systems more versatile, robust and cost-efficient. Some researchers combine climbing and walking techniques with a modular approach, a reconfigurable approach, or a swarm approach to realize novel prototypes as flexible mobile robotic platforms featuring all necessary locomotion capabilities. The purpose of this book is to provide an overview of the latest wide-range achievements in climbing and walking robotic technology to researchers, scientists, and engineers throughout the world. Different aspects including control simulation, locomotion realization, methodology, and system integration are presented from the scientific and from the technical point of view. This book consists of two main parts, one dealing with walking robots, the second with climbing robots. The content is also grouped by theoretical research and applicative realization. Every chapter offers a considerable amount of interesting and useful information

Machining-based coverage path planning for automated structural inspection

The automation of robotically delivered nondestructive evaluation inspection shares many aims with traditional manufacture machining. This paper presents a new hardware and software system for automated thickness mapping of large-scale areas, with multiple obstacles, by employing computer-aided drawing (CAD)/computer-aided manufacturing (CAM)-inspired path planning to implement control of a novel mobile robotic thickness mapping inspection vehicle. A custom postprocessor provides the necessary translation from CAM numeric code through robotic kinematic control to combine and automate the overall process. The generalized steps to implement this approach for any mobile robotic platform are presented herein and applied, in this instance, to a novel thickness mapping crawler. The inspection capabilities of the system were evaluated on an indoor mock-inspection scenario, within a motion tracking cell, to provide quantitative performance figures for positional accuracy. Multiple thickness defects simulating corrosion features on a steel sample plate were combined with obstacles to be avoided during the inspection. A minimum thickness mapping error of 0.21 mm and a mean path error of 4.41 mm were observed for a 2 m² carbon steel sample of 10-mm nominal thickness. The potential of this automated approach has benefits in terms of repeatability of area coverage, obstacle avoidance, and reduced path overlap, all of which directly lead to increased task efficiency and reduced inspection time of large structural assets