Pipe Inspection Research Articles

Soft hopping and crawling robot for in-pipe traveling

Pipe inspection is of great importance from both safety and cost perspectives. Despite extensive research, in-pipe robots with multi-locomotion capability have not been fully explored. Here, we develop a multi-locomotion soft robot, with a compact yet robust structure, that can hop for speed and crawl for maneuverability in horizontal and vertical pipes for pipe inspection. The robot consists of two motors, cables, and several longitudinally arranged elastic ribbons. These ribbons, with strategically designed profiles, are 3D-printed and can be buckled into three-dimensional shapes by pulling cables, thereby achieving hopping and crawling (forward and backward) by issuing different actuation sequences and parameters of the two motors. We studied the effect of ribbon design and pulling/releasing duration on the hopping and crawling performance. Our findings may shed light on the development of in-pipe robots with new functionality and applications.

Pneumatic Duplex-Chambered Inchworm Mechanism for Narrow Pipes Driven by Only Two Air Supply Lines

Small in-pipe robots are key to improving pipe inspection procedures, especially for narrow diameters. However, robotic locomotion in such spaces, namely achieving a high locomotion performance with a narrow and flexible mechanism, is difficult. The novel in-pipe locomotion mechanism proposed in this letter achieves rapid locomotion through narrow pipes by a unique duplex-chambered structure. The mechanism achieves smooth bi-directional inchworm locomotion by a combination of expandable silicone rubber and a coil spring and is fully controlled by only two air supply lines. The concept and locomotion technique, including a mathematical analysis and discussion from the viewpoint of operational pressure, are presented herein. Several experiments on the prototyped mechanism were performed to elucidate its characteristics. The results of locomotion tests through horizontal, vertical, and bent pipes showed that the mechanism can horizontally navigate through 25-mm pipes at 45.5 mm/s, which is the fastest yet reported for this size of bi-directional in-pipe robot.

Data-Driven Framework for Modeling Productivity of Closed-Circuit Television Recording Process for Sewer Pipes

AbstractClosed-circuit television (CCTV) is widely used in North America for sewer pipe inspection due to several benefits, such as easy operation and lower upfront costs. To be useful, video foota...

Application of Ultrasonic Guided Waves for Inspection of High Density Polyethylene Pipe Systems

The structural integrity assessment of thermoplastic pipes has become an interesting area of research due to its elevated usage in the liquid/gas transportation industry. Ultrasonic guided wave testing has gained higher attention from industry for the inspection of elongated structures due to the reduced inspection time and cost associated with conventional non-destructive testing techniques, e.g., ultrasonic testing, radiography, and visual inspection. Current research addresses the inspection of thermoplastic pipes using ultrasonic guided waves as a low cost and permanently installed structural health-monitoring tool. Laboratory and numerical investigations were conducted to study the potential of using ultrasonic guided waves to assess the structural health of thermoplastic pipe structures in order to define optimum frequency range for inspection, array design, and length of inspection. In order to achieve a better surface contact, flexible Macro-Fiber Composite transducers were used in this investigation, and the Teletest® Focus+ system was used as the pulser/receiver. Optimum frequency range of inspection was at 15−25 kHz due to the level of attenuation at higher frequencies and the larger dead zone at lower frequencies due to the pulse length. A minimum of 14 transducers around the circumference of a 3 inch pipe were required to suppress higher order flexural modes at 16 kHz. According to the studied condition, 1.84 m of inspection coverage could be achieved at a single direction for pulse-echo, which could be improved by using a higher number of transducers for excitation and using pitch-catch configuration.

Wheel Based Pole Climbing Structure Built for Replacing Manpower in Hazardous Environments and Creating a Platform for Telegraph Pole Deicing and Reconstruction

A common phenomenon in high latitude countries would be a hazardous environment during the winter. Electrical lights and telegraph pole are covered in ice and therefore caused trouble for workers and electrician whose job is to maintain their functions. This climb bot is expected to have various application range, primarily used to replace human workforce and reduce the injuries caused by falling from a considerable height. Scientists have been proposing various ideas of similar robots, such as inspections of vertical pipes in a nuclear power plant, or the funnel for industrial use. The robot I designed will be dealing with the telegraph pole in a metropolitan area, which froze in the winter. Currently, due to the restriction of time and material, the robot is only capable of essential climbing functions, but it is possible to add functions such as deicing and cleaning in the future. This article will further explain the design and function of the robot with statistics while giving examples of how other similar design works.

A novel magnetic force transmission eddy current array probe and its application for nondestructive testing of defects in pipeline structures

Eddy current nondestructive testing (ECT) method is an efficient method based on electromagnetic induction for quantitative nondestructive evaluation of defects in the pipeline structure, due to its advantages of high detectability, non-contact and quick scanning. How to realize the probe scanning is a key issue for the long distance pipe inspection when the probe is located inside the tube. To address this problem, in this paper, a novel type of magnetic force transmission eddy current array split type probe has been proposed and developed to detect the defects in the pipeline structure. Firstly, the magnetic force transmission eddy current probe is proposed and designed, which includes excitation device outside the pipe and pickup device inside the pipe. The whole probe can simultaneously move along the pipe under the function of magnetic force. Secondly, the advantage of this proposed split type probe is validated through numerical simulation and experiment, which is that the detection signal cannot be saturated for deep buried defect, compared to the reflection type probe. Thirdly, the array structure pickup probe is designed and its merit is verified through simulation and experiment, which is that the detection sensitivity and efficiency are improved significantly. Finally, the proposed magnetic force transmission eddy current array probe is applied to detect one aluminum pipe with crack defects. The depth, axial position and circumferential position of the cracks can be successfully determined according to the proposed novel probe in this study.

Simulation of the behavior of biologically-inspired swarm robots for the autonomous inspection of buried pipes

The use of robots for the inspection of buried pipelines has gained popularity over the past decade. In this paper we move the vision forward by examining what behavior and attributes would be required for these robots to become autonomous and pervasive within buried water pipe infrastructure. We present the results from novel simulations to evidence the inspection capability of autonomous robots, investigating operation, cooperation and communication attributes. The simulation uses a biologically-inspired behavior that provides complete and consistent coverage of real life example clean water distribution management areas. We show that autonomous robots could operate without a centralized controller and benefit from having some degree of in-pipe communication. We evidence the ability to adapt to changes in communication, speed, and flow conditions. The mathematical model that we derive through the simulation is scalable with the change of network length, topology, robots’ speed and number. This work paves the way and sets the specifications for practical development of autonomous pervasive robots for the inspection of complex pipe networks.

Morphological evolution for pipe inspection using Robot Operating System (ROS)

ABSTRACT In many manufacturing processes, sensor agents specifically adapt to explore pipes and other constrained environments filled with fluid are usually needed for monitoring purposes. However, in some of these environments only miniaturized agents can be used. Furthermore, these agents might be kinetically passive, due to limited resources and size. Therefore, designing and using these agents can be difficult. One possible solution to this problem is to change the agents’ morphology, such that optimally shaped agents reach target destinations simply by passively moving through the fluid. Here, we propose an evolutionary scheme for evolving the agent’s morphology to reach a predefined desired point in a fluid environment. This scheme includes a genotype-phenotype mapping based on Lindenmayer-Systems, as well as custom reproduction operators, selection criterion, and fitness function. In order to allow the simulation of irregularly shaped bodies underwater, we develop a simulation framework based on the Robot Operating System and the Unmanned Underwater Vehicle package. We test the proposed method on a set of 10 target points in a pipe inspection scenario. Results show that the evolved agents reach the target points with a distance error smaller than 5% in the worst case, and a standard deviation of 1.1% over 10 repeated experiments.

Weld quality inspection of small-diameter thin-walled pipes by a laser ultrasonic method.

Defect inspection of small-diameter thin-walled pipes is a difficult problem in the field of nondestructive testing. In this paper, a new detection method based on laser ultrasonics and guided circumferential wave technology is proposed and used to inspect the defects in pipes. First, a theoretical model based on the theory of acoustic propagation in solids is proposed for the small-diameter thin-walled pipes. The dispersion characteristics of the guided circumferential waves of thin-walled pipes are obtained by numerical simulation. Second, a laser ultrasonic system is constructed and used to detect the flaws in the small-diameter thin-walled pipes. Finally, the laser ultrasonic system is used to analyze the welding quality of stainless steel pipes with a diameter of 4.20 mm and a wall thickness of 0.30 mm. The experimental results are in agreement with the theoretical analysis, which demonstrates the reliability and practicability of the laser ultrasonic method in the weld quality inspection of small-diameter thin-walled pipes.

Factors Affecting Spatial Resolution in Pulsed Eddy Current Inspection of Pipe

Pulsed eddy current is an emerging technique for measuring wall thinning of steel under insulation. Ideally, it would be desirable to obtain the most localised information of pipe condition possible. The localization of information is constrained by the flow of eddy currents in the pipe. This in turn is heavily influenced by the orientation of the probe. This paper examines three different probe orientations, representative of all probe types for their influence on eddy current flow. All three orientations will have difficulty accurately measuring highly localized thinning, because the eddy currents that give rise to their signal spread out rapidly way from the thin region in the long time signal decay. Of the three orientations, the longitudinal one does the best job of localizing the eddy currents directly under the probe.

Characteristics of T(0, 1) Guided-Wave Point-Focusing Electromagnetic Acoustic Transducer for Pipe Inspection

Electromagnetic acoustic transducers (EMATs) are widely used in the field of non-destructive testing (NDT) and non-destructive evaluation (NDE) due to their advantages of non-contact and applicability in complex environments. However, their low energy-conversion efficiency restricts their application in industrial testing. This work proposes a newly designed focusing EMAT based on the T(0, 1)-wave in a pipe to improve the energy conversion efficiency of EMATs. The focal length and defect width are investigated in this paper, and the advantages of the newly designed point-focusing transducer are shown in comparison with traditional unfocused transducers. Results show that the newly designed pipe focusing EMAT can increase the intensity of the defect reflection wave by around 60%, and the reflected wave intensity can be enhanced by 70% in the experiment when compared to the unfocused one.

Microwave Non-destructive Evaluation of Glass Reinforced Epoxy and High Density Polyethylene Pipes

Owing to their inherent advantages, non-metallic structures such as glass reinforced epoxy (GRE) pipes and high-density polyethylene (HDPE) pipes are rapidly replacing their steel counterparts in pipeline infrastructures. However, non-metallic pipes are vulnerable to a variety of defects which compromise their structural integrity. Hence, periodic inspection of these structures is incumbent to ensure their structural integrity and avoid catastrophic in-service failures. Microwave and millimeter wave non-destructive evaluation techniques have shown great potential for inspecting non-metallic structures due to their high sensitivity, resolution, and cost-effectiveness. However, most of the previous investigations performed on microwave non-destructive testing (NDT) of these particular structures are deemed limited since these investigations considered one probe type and often conducted over narrow frequency band. Furthermore, many of the previous microwave NDT investigations considered unrealistically large defects which renders the reported conclusions about the performance envelope of microwave NDT of non-metallic pipes rather inaccurate. Consequently, an uncertainty still exists in the domain with regards to detection capability of the method when the defects in the pipes are actually small in size. Unlike all previous investigations, a comprehensive and realistic microwave imaging of GRE and HDPE pipes with embedded defects of practical importance is demonstrated in this paper. In order to image these defects, various near-field probes operating at wide range of frequencies are employed and compared herein. The relative performance and the effectiveness of microwave NDT for non-metallic pipe inspection using these probes are quantitatively reported. Furthermore, the images of the HDPE pipe produced by microwave probes are benchmarked to phased array ultrasonic testing.

Development of a wholly flexible surface wave electromagnetic acoustic transducer for pipe inspection

Development of a wholly flexible surface wave electromagnetic acoustic transducer for pipe inspection

Experimental and numerical study of internal erosion around submerged defective pipe

Ground subsidence induced by internal erosion around defective sewer pipes commonly occurs in urban areas of many cities over the world, which has caused substantial socioeconomic loss. Professional pipe design, inspection and maintenance demand a comprehensive understanding of the internal erosion mechanism due to defective pipes. This paper conducts a series of experimental, theoretical and numerical analyses aiming to propose a new method quantifying the erosion process around defective pipes. In this study, a laboratory experimental test of internal erosion was conducted using gap-graded soils, followed by the derivation of a nonlinear incremental governing equation for quantifying the erosion rate of soil on the basis of experimental results. After that, a new type of element was established to incorporate the proposed governing equation of erosion into Mohr-Coulomb constitutive soil model. Finally, this new element was adopted in a 2D soil-fluid coupled finite element analysis of soil erosion due to pipe defect. Results indicate that (1) the hydraulic head greatly affects cavity formation and soil loss, whereas the defect types have a little effect on eroded region, (2) visual images during test show that the soil erosion gradually slows down and eventually stabilizes along with the forming of soil skeleton, (3) the numerical results match well with the experimental results, demonstrating the effectiveness of both the theoretical method and numerical tool for the analysis of soil erosion around defective pipes.

Metamorphic tensegrity structure for pipe inspection

This paper proposes a new concept of metamorphic tensegrity structure for pipe inspection. A new structural deformation technique is developed that can be employed to design a non-complex and lightweight robot or vehicle. This concept is to deform the cross-shaped tensegrity structure by using the cooperation of prismatic actuators (PAs) and passive joints with locking mechanisms called restrictor mechanisms (RMs). Two control levels are designed to control the structural deformation: A high-level controller for motion patterns and low-level controllers to locally control the PA lengths and restrict the cable lengths of four RMs. Experiments show that the proposed deformation technique can deform the shape and size of the tensegrity structures with the aim of creating a new generation of pipe inspection robots.

Autonomous Pipe Inspection Robot

A pipe inspection robot is a machine used to inspect, provide real time solutions to the pipes and cleaning of the pipes (scales or the deposits formed due to the fluid flow). There are already number of designs available for the pipe inspection robot. This paper proposes a new pipeline inspection robot with parallelogram linkage mechanism which is designed for inspection of pipes ranging from 100 mm (internal diameter) to 250 mm (internal diameter). The robot is driven by three chained wheel mechanisms each of them separated by 120 degrees. The mechanism allows the autonomous movement of the robot and hence saves time. It has night vision camera enabled mode for image processing to study the corrosion rate of the pipe surface as well as the condition of the pipe inner surface. The kinematic model of the bot is modeled in SolidWorks and the prototype is developed. The performance of the robot is verified both by stimulation and experimentally.

Two-degree-of-freedom pipe selection mechanism using contraction and extension unit composed of single tube and its application to a gas pipe inspection robot

Two-degree-of-freedom pipe selection mechanism using contraction and extension unit composed of single tube and its application to a gas pipe inspection robot

Improvement of Pipe Holding Mechanism and Inchworm Type Flexible Pipe Inspection Robot

Improvement of Pipe Holding Mechanism and Inchworm Type Flexible Pipe Inspection Robot

Proposal and evaluation of a high-rigidity joint attachment for a peristaltic robot for pipe inspection in an actual environment

Proposal and evaluation of a high-rigidity joint attachment for a peristaltic robot for pipe inspection in an actual environment

Application of UAV for Sewer Pipe Inspection

Application of UAV for Sewer Pipe Inspection