WO2020065659A1

WO2020065659A1 - Spherical robot for internal inspection of pipelines

Info

Publication number: WO2020065659A1
Application number: PCT/IN2019/050134
Authority: WO
Inventors: Ajayraj RAMINENI; Rajagopal PRABHU; Krishnan BALASUBRAMANIAN; Avinash Kumar
Original assignee: INDIAN INSTITUTE OF TECHNOLOGY MADRAS (IIT Madras)
Priority date: 2018-09-24
Filing date: 2019-02-20
Publication date: 2020-04-02

Abstract

A modular robotic device for internal inspection of pipelines is disclosed. The device of spherical or ellipsoidal shape includes a transparent annulus sealed between a pair of domes. The device includes a rotatable shaft mounted about an axis of the outer shell and coupled to a pair of steering plates, configured to steer the device into a rotational motion along the fluid flow direction. A stabilization assembly includes a mounting plate attached to the shaft is used to dampen oscillations. A visual sensor is mounted on the mounting plate and configured to capture images of internal defects of the pipeline through the transparent annulus. An acoustic sensor is configured to detect leaks using acoustic signals as acoustic data. A processing unit, mounted on the mounting plate, is configured to log the visual and acoustic data for inspection of the inner surface of the pipeline.

Description

SPHERICAL ROBOT FOR INTERNAL INSPECTION OF PIPELINES

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Indian Patent Application No. 201841035890, titled “SPHERICAL ROBOT FOR INTERNAL INSPECTION OF PIPELINES”, filed on September 24, 2018.

FIELD OF THE INVENTION

[0002] The disclosure relates generally to robotics for in-line inspection of pipelines and, in particular, to systems, methods, and devices for detecting and locating anomalies in fluid-filled pipelines.

DESCRIPTION OF THE RELATED ART

[0003] Pipelines are hollow cylindrical conduits used for transportation of fluids, i.e., gases or liquids. Typically, pipelines are constructed using metals and a network of pipelines are deployed over large distances for transporting oil, gas, water, etc. For instance, pipelines may stretch across neighbourhoods, communities, water bodies, forests, deserts, for transportation purposes. Depending upon the industry, distance, or the fluid transported, pipelines may be buried under ground, exposed to atmosphere, or submerged under water.

[0004] Exposure to any extreme or harsh conditions could weaken the integrity of the pipeline structure. In many instances, structure of pipelines may undergo corrosion or damage causing leakage. In some instances, pipelines may also develop blockages, gas pockets, pitting, sedimentation, etc. Hence, many industries that rely heavily on pipelines, such as petroleum, natural gas, manufacturing companies, and the like, could face huge losses. More importantly, such scenarios could lead to discharge of industrial effluents that may be potentially dangerous to the environment. Therefore, continuous maintenance of pipelines remains a major concern and large resources are allocated for this purpose. [0005] Tools for monitoring the condition of pipelines are in great demand. For instance, pipeline maintenance services, in India, are provided by external agencies, which are not easily affordable due to high costs involved. Additionally, non-destructive evaluation (NDE) sensors based on magnetic flux leakage (MFL) are incorporated in Pipeline Inspection Gauge (PIG), also known as intelligent or smart PIGs. The intelligent PIGs mainly serve two purposes: firstly, the PIGs clean the internal surface of the pipeline and remove blockages; secondly, the PIGs provide surface anomalies details, such as cracks, pitting, weld defects and abnormalities based on the NDE techniques (MFL, Ultrasonic, etc.). Moreover, pipeline inspection is typically performed only during shutdown period, and the investigations are done using techniques, such as fluorescent based visual inspection, laser profiling, etc. In addition to this, MFL technology used in PIGs are reliable in characterizing defects, inclusions, and corrosion only in ferromagnetic magnetic conduits. NDE techniques including ultrasonic and eddy current for fault (cracks, pitting, etc.) detection in both ferromagnetic and non-ferromagnetic materials can be expensive to implement.

[0006] Various publications have attempted to address some of the challenges associated with pipeline maintenance as described above. For instance, WO2016174284A1 discloses device for detecting water leaks in pipelines and leak detection method. CN20183283U discloses a pipeline cleaning robot. US8098063B2 discloses an untethered, unpowered, rollable device to sense condition of pipeline wall. CN207292187U discloses spherical mobile robots for exploration environment.

SUMMARY OF THE INVENTION

[0007] The present subject matter relates to systems and devices for internal inspection and survey of fluid filled pipelines using sensors.

[0008] According to one embodiment of the present subject matter, a modular device for visual and acoustic inspection of pipelines containing a moving fluid is provided. The device includes a transparent annulus sealed between a pair of domes to form an outer shell of spherical or ellipsoidal shape. Further, the device includes a rotatable shaft mounted about an axis of the outer shell and coupled to a pair of steering plates. The steering plates are configured to steer the device into a rotational motion along the fluid flow, wherein the shaft rotates independent of the outer shell. A stabilization assembly is housed in the shell to dampen oscillations during motion. The stabilization assembly includes a mounting plate attached to the shaft. The mounting plate is configured to maintain centre of mass of the device at a predetermined position. A visual sensor is mounted on the mounting plate and configured to capture images of internal defects of the pipeline as visual data through the transparent annulus. An acoustic sensor is configured to detect leaks using acoustic signals as acoustic data. A processing unit is mounted on the mounting plate, wherein the processing units are configured to log the visual and acoustic data for inspection of the inner surface of the pipeline.

[0009] The device further includes bearings or bushing to couple the shaft and the shell, wherein the bearings or bushing enable rotation of the shell independent of rotation of the shaft. The stabilization assembly includes at least one magnet. The mounting plate is further configured to mount plurality of batteries. The device further includes a communication unit configured to communicate the logged visual and acoustic data to a remote computing device, wherein the remote computing device generates a three- dimensional map of the inner surface of the pipeline. The stabilization assembly further comprises inertial measurement unit, encoders, ultrasonic sensors, magnetic flux leakage sensors, magnetometers, or temperature sensors. Further, the centre of mass is towards the bottom of the device. The device is connected to a remote system, wherein the remote system comprises at least a processing unit, a memory unit, and a network device.

[0010] According to another embodiment of the present subject matter, modular device for visual and acoustic inspection of pipelines containing a moving fluid is provided. The device includes a remotely-controlled, motor-propelled first device; and a second device connected to the first device through a chassis. The second device includes an outer shell comprising a pair of domes sealed to opposite ends of a transparent annulus; a rotatable shaft mounted about an axis of the outer shell, wherein the shaft rotates independently of the outer shell; a stabilization assembly housed in the shell to dampen oscillations during motion, comprising: a mounting plate attached to the shaft, wherein the mounting plate is configured to maintain centre of mass of the device at a predetermined position. The second device further includes a visual sensor mounted on the mounting plate and configured to capture images of internal defects of the pipeline as visual data through the transparent annulus; an acoustic sensor configured to detect leaks using acoustic signals as acoustic data; a processing unit mounted on the mounting plate, wherein the processing units are configured to log the visual and acoustic data for inspection of the inner surface of the pipeline for inspection of the surface of the pipeline.

[0011] Further, the chassis includes a frame connecting the first device and the second device, a spring-loaded telescopic rods coupled to the frame, wherein the spring- loaded telescopic rod is configured to transfer the propulsive force generated by the first device to the second device, and a steering mechanism configured to control the direction of device motion, wherein the steering mechanism comprises: a servo motor, and a servo arm coupled to the servo motor and the frame, wherein the servo arm transfers the rotational motion from the servo motor to the frame for changing the direction of the device motion. Further, the first device comprises an outer shell comprising a pair of domes coupled with a rubber grip; and an electric motor controlled from a remote location. The shaft of the electric motor is coupled to a hub of a wheel structure. The electric motor is coupled to a tether connected to a remote base location. An operator from the remote base location controls device motion via the tether. The second device further comprises a communication unit configured to communicate the logged visual and acoustic data to a remote computing device, wherein the remote computing device generates a three-dimensional map of the inner surface of the pipeline.

[0012] According to another embodiment of the present subject matter, a method for visual and acoustic inspection of pipelines containing a moving fluid is provided. The method includes recording, by acoustic sensors of the device, acoustic data indicating defects in the pipeline. Next, the method includes capturing, by visual sensors of a device, visual data comprising images of internal defects of the pipeline. Further, the method includes determining pipeline data by inertial measurement unit sensors (IMU), distance travelled by the device in the pipeline and number of bends traversed in the pipeline. In the next step, the method includes correcting, by an encoder of the device, errors in pipeline data. Finally, the method includes determining, by a processing unit of the device, to obtain a final data based on the acoustic data, visual data, and pipeline data indicative of defects in inner surface of the pipeline.

[0013] The sensor data is stored in a memory unit of the device for processing at a later stage. The final sensor data is communicated to a server for generating a three dimensional map of the inner surface of the pipeline. The acoustic data provides information on pressure difference between pipeline and environment to indicate defects in the pipeline. The method includes detecting and locating holes, leaks, cracks, pipe undulations, gas pockets, corrosion, blockages, pitting, or sedimentation. Further, the pipeline is a non-ferromagnetic pipeline.

[0014] According to another embodiment of the present subject matter, a non- transitory computer readable medium having stored therein instructions executable by a processor for inspection of pipelines is provided. The instructions include communicating with a modular robotic device that propels through a pipeline to capture data from one or more regions of interest, receiving the pipe inspection data from one or more sensors located in the device, storing the data comprising visual and acoustic data of inner surface of the pipeline, processing the data to determine the characteristics of the pipelines, generating a three dimensional map from the received inspection data and displaying the map of the internal features of the pipe for internal inspection of the pipelines. Further, the instructions include remotely controlling the propulsion of the device, providing a real-time view of the internal structure of the pipeline and to actively control direction of the device motion for steering the device.

[0015] This and other aspects are disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The invention has other advantages and features which will be more readily apparent from the following detailed description of the invention and the appended claims, when taken in conjunction with the accompanying drawings, in which:

[0017] FIG. 1A illustrates a modular device for internal inspection of fluid-filled pipelines, according to an embodiment of the present subject matter.

[0018] FIG. 1B illustrates an exploded view of a modular device for internal inspection of pipelines, according to an embodiment of the present subject matter.

[0019] FIG. 1C illustrates a stabilization assembly of the modular device, according to an embodiment of the present subject matter.

[0020] FIG. 2A and 2B illustrate a modular device for internal inspection of fluid- filled pipelines, according to another embodiment of the present subject matter.

[0021] FIG. 3 illustrates a schematic diagram of the electronic modules of the modular device in communication with a remote system, according to one example of the present subject matter.

[0022] FIG. 4 illustrates a method for visual and acoustic inspection of pipelines containing a moving fluid, according to one example of the present subject matter.

[0023] FIG. 5 illustrates pipeline with surface anomaly and simulated leak, according to one example of the present subject matter.

[0024] FIG. 6 illustrates an internal pipeline view recorded by the robotic device, according to one example of the present subject matter.

[0025] FIG. 7 illustrates acoustic emission inside the pipeline, according to one example of the present subject matter.

[0026] Referring to the drawings, like numbers indicate like parts throughout the views. DET AILED DESCRIPTION

[0027] While the invention has been disclosed with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt to a particular situation or material to the teachings of the invention without departing from its scope.

[0028] Throughout the specification and claims, the following terms take the meanings explicitly associated herein unless the context clearly dictates otherwise. The meaning of "a", "an", and "the" include plural references. The meaning of "in" includes "in" and "on". Referring to the drawings, like numbers indicate like parts throughout the views. Additionally, a reference to the singular includes a reference to the plural unless otherwise stated or inconsistent with the disclosure herein.

[0029] The invention in its various embodiments proposes modular robotic devices and systems for internal inspection of pipelines. In particular, the present subject matter discloses modular device that are propelled passively or motorized in harsh conditions, such as inflammable environment and/or high pressure.

[0030] A modular device for internal inspection and survey of fluid-filled pipelines is illustrated in FIG.1A, according to an embodiment of the present subject matter. The modular device 100 may be passively propelled inside a pipeline 160, which transports a fluid 150. In various embodiments, the pipeline may be a ferromagnetic pipeline or a non-ferromagnetic pipeline and the fluid may be any gas, or liquid, such as oil, water, and the like. The modular device 100 may be propelled based on the pressure differential in the pipeline, for instance, the device 100 may rotate using the flow of the fluid 150 in the pipeline 160. The device may collect information about the pipeline as data that is captured using sensors for surveying the health of the pipelines.

[0031] An exploded view of the modular device 100 for internal inspection of fluid-filled pipelines is illustrated in FIG. 1B, according to an embodiment of the present subject matter. The modular device 100 may primarily include an outer shell, a transparent annulus 110, a rotatable shaft 104, a stabilization assembly, sensors, and a processing unit. The outer shell may include a pair of domes 102-A, 102-B, which are sealed together using a transparent annulus 110. The modular device is designed to withstand high pressure, harsh conditions, and operate in inflammable environment. For instance, the outer shell may be made up of polymers such as polyoxymethylene (Delrin) that can withstand heavy load. The transparent annulus 110 may be made of acrylic polymeric material, such as poly (methyl methacrylate) (Plexiglass). In some embodiments, the pair of domes 102 and the transparent annulus 110 may be coupled using a male-female joint mechanism. For example, the domes may include a female connecting mechanism, such as a groove, and the transparent annulus 110 may include a male connecting mechanism. The groove may further include a silicon adhesive for robust connection.

[0032] The rotatable shaft 104 may be mounted about an axis of the outer shell and coupled to a pair of steering plates 106- A, 106-B. The steering plates 106- A, 106-B may be positioned on opposite sides of the shell and configured to steer the device into a rotational motion along the fluid flow, such that the shaft rotates independent of the outer shell. The pair of steering plates 106-A, 106-B are configured to passively propel the device into a rolling motion. The steering plates 106-A, 106-B propel the device inside the pipeline using the drag force of the flow of the fluid and the modular device is steered towards the direction of the flow. In other embodiments, the device may be actively propelled as will be discussed later.

[0033] In various embodiments, the device further comprises bearings or bushings 112 for coupling the shaft 104 and the shell. The bearing is configured to enable the rotation of the shell independent of rotation of the shaft 104. In various embodiments, the bearing 112 may be a plain bearing, ball bearing, roller bearing, jewel bearing, fluid bearing, magnetic bearing, flexure bearing, and the like. [0034] The stabilization assembly 200 is illustrated in FIG. 1C, according to an embodiment of the present subject matter. The stabilization assembly 200 may be housed in the shell to dampen oscillations during motion. The stabilization assembly includes a mounting plate 108 attached to the shaft 104, wherein the mounting plate 108 is configured to maintain centre of mass of the device at a predetermined position. In various embodiments, the mounting plate 108 may include a bottom mounting surface and an upper mounting surface. The bottom mounting surface and the upper mounting surface may include a plurality of components for inspection and stabilization purposes. The bottom mounting surface may carry one or more batteries 212 to power the device. The bottom mounting surface may further be configured to carry counterweights such that the center of mass of the device 100 is located near the lower portion of the device 100. The counterweight may be adjusted so as to maintain the device orientation roughly the same during operation. The bottom mounting surface may further include a magnet 206 to dampen oscillations of the mounting plate, configured to be attractive to another magnet or ferromagnetic strip at a corresponding location at the bottom of the annulus 110. As the outer shell rotates, the orientation of the mounting plate is configured to go back to the original position due to restoring torque. In some embodiments the magnetic field associated with the magnet moves through the pipeline, which is a conductor. An eddy current is induced in the pipeline due to the magnetic field’s movement. The flow of electrons in the pipeline creates an opposing magnetic field to the magnet which results in damping of the magnet. This, in turn, damps the oscillations of the mounting plate.

[0035] The upper mounting surface may mount a plurality of electronic components including processing unit 210. The electronic components mounted on the upper mounting surface may include plurality of sensors, processing units, memory unit, audio card, etc., to inspect inner surface of the pipeline. In some embodiments, the sensors may include visual sensors. The visual sensors may include at least a camera and a light emitting diode to detect internal defects of the pipeline. The visual sensors may be positioned in alignment with the transparent annulus, as shown in FIG. 1B, to capture images of the pipeline internally. The acoustic sensors may include microphone, hydrophone, audio card, etc. The microphone may be used to receive acoustic data reflected from the inner surface of the pipeline. The received data may be stored in the audio card for further processing. In various embodiments, the upper mounting surface may further include inertial measurement unit, encoders, ultrasonic sensors, magnetic flux leakage sensors, magnetometers, temperature sensors. The audio and video data may be captured in smooth manner as the center of mass at the bottom of the device ensures that the orientation of the inspection unit is not affected. The processing units 210 may be configured to log the sensor data of the inner surface of the pipeline. In one embodiment, the sensor data may be stored in a memory unit. Referring back to FIG. 1B, the device 100 may include acoustic sensors 114 connected to at least one of the steering plates 106. Further, the device 100 may include a charging terminal 116 configured to receive power supply. Additionally, the device may include end caps 118 to avoid the interaction of the fluid with the sensors and charging terminal. In various embodiments, the robotic device may include one or more batteries.

[0036] A modular robotic device 300 for visual and acoustic inspection of pipelines containing a moving fluid is illustrated in FIG. 2A and FIG. 2B, according to another embodiment of the present subject matter. The device 300 may include a remotely-controlled, motor-propelled first device 302 and a second device 304 connected to the first device 302 through a chassis 306. The first device 302 may include an outer shell 308 comprising a pair of domes coupled with a rubber grip 310. An electric motor 312, which may be controlled from a remote location, may be coupled with the outer shell 308. The second device 304 may include an outer shell, a rotatable shaft, stabili ation assembly 200, visual sensors 208, acoustic sensor 114, a processing unit 210. The outer shell may include a pair of domes sealed to opposite ends of a transparent annulus. The rotatable shaft may be mounted about an axis of the outer shell, such that the shaft rotates independently of the outer shell. The stabilization assembly is housed in the shell to dampen oscillations during motion. As described earlier, the stabilization assembly may include a mounting plate attached to the shaft, wherein the mounting plate is configured to maintain centre of mass of the device at a predetermined position. The second device further includes a visual sensor mounted on the mounting plate and configured to capture images of internal defects of the pipeline as visual data through the transparent annulus 110. The device acoustic sensors may be configured to detect leaks using acoustic signals as acoustic data. The processing unit may be mounted on the mounting plate, wherein the processing unit is configured to map the visual and acoustic data for inspection for inspection of the surface of the pipeline.

[0037] In various embodiments, the chassis 306 may include a frame 318, spring- loaded telescopic rods 320, and a steering mechanism. The spring-loaded telescopic rods 320 coupled to the frame and are configured to transfer the propulsive force generated by the first device 302 to the second device 304. In various embodiments, the spring-loaded telescopic rods 320 may be coupled to the frame 318 using ball-socket joint. In some embodiments, the frame components 318 may be coupled to each other using pin-joint. The steering mechanism configured to control the direction of system motion. The steering mechanism includes a servo motor 322 and a servo arm 324 coupled to the servo motor 322. The servo arm 324 transfers the rotational motion from the servo motor to the frame 318 for changing the direction of the system motion.

[0038] Further, the domes of the first device 304 are coupled to each other with a rubber grip 310. In some embodiments, the rubber grip 310 may be attached to a rim of a wheel structure 326, which may be connected to the two dome structures. In some embodiments, shaft of the electric motor 312 may be connected to hub of the wheel structure 326. In various embodiments, the electric motor 312 may be configured to be controlled from a remote location. For example, the electric motor may be coupled to a remote control unit, which receives commands from a base location to control the rotation of the electric motor shaft. In another example, the electric motor may be coupled to tether 328, which transfers signals from a remote location. The length of the tether may be proportional to the length of the pipeline.

[0039] A schematic diagram of the electronic modules of the robotic device is illustrated in FIG. 3, according to an embodiment of the present subject matter. The electronic modules may primarily include processing units 210, inspection unit 402, and power sources 212. The various connections between the blocks in the schematic have been represented with dotted lines and solid lines. The dotted lines represent transfer of power and the solid lines represent transfer of data. The inspection unit 402 may include acoustic sensors 404 and visual sensors 406, both of which are controlled by the processing unit 210. The acoustic sensors 404 may include audio card 408 and a microphone 410. The acoustic sensors 404 may be used to detect and record the audio inside the pipeline to determine pressure differentials. The pressure differential may be determined by a detecting difference in acoustic signal, which may indicate presence of an opening, a hole or leak or other abnormalities are encountered in pipeline. The audio recordings may be stored in the audio card for further processing. The processing unit may be configured to process the audio recording to determine damages and other characteristics of the pipelines. The processing may involve methods, such as Fourier transformation, Hilbert Transformation, Kalman filter, or any other existing techniques. In some embodiments, a transmitting device may be used for transmitting audio signals in the pipeline. The reflected audio signals may be captured by the acoustic sensors 404 to determine pipeline damages. The visual sensors 406 may include camera 412 and LED flash light 414 for obtaining visual data of the pipeline. The power supply to LED flash light 414 may be controlled using a switch 416. A map of the internal features of the pipe is generated from the visual data. In one embodiment, the mapping may be performed using image processing techniques, for example, the number of welded joints may be counted using image processing tools from the recorded video. In various embodiments, the camera may capture images of the pipeline and store it in a memory unit (not shown in figure) or provide real-time video of the internal structure of the pipeline.

[0040] Further, the inspection unit may also include inertial measurement unit (not shown in figure), which contains both an accelerometer (3 axis) and a gyroscope (3 axis). The accelerometer may be configured to measure the distance traveled and the gyroscopes give the number of bends inside the pipeline. Further, an encoder may be used to minimize the error generated by the IMU.

[0041] In some embodiments, the captured audio and video data may be processed by the processing unit 210. In other embodiments, the captured audio and video data may be processed at a remote server 420 that may include processing units 422, memory unit 424, and a network device 426. In various embodiments, the remote server 420 may be a computing system that communicates with the robotic system using the network device 426 and obtains the sensor data. The processing unit 422 generates a three dimensional map of the inner surface of the pipeline based on the visual and acoustic data logged at the device. In some embodiments, the captured audio and video data may be retrieved from the robotic device after completing the inspection procedure. In some embodiments, the robotic device may include a communication unit for communicating the captured audio and video data to one or more remote servers. For example, the communication may be performed using communication protocols, such as Global System for Mobile Communications (GSM), General Packet Radio Services (GPRS), Enhanced Data GSM Environment (EDGE), Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (WCDMA), Bluetooth, High Speed Packet Access (HSPA), Long Term Evolution (LTE), 5G, 5G-New Radio, and Worldwide Interoperability for Microwave Access (WiMAX). The data may be communicated to other computing devices for analysis, for example, the computing devices may include laptop computers, tablet computers, desktop computers, smartphones, personal digital assistants (PDA), smart devices, or the like.

[0042] A method for visual and acoustic inspection of pipelines containing a moving fluid is illustrated in FIG. 4, according to one embodiment of the present subject matter. The method 500 includes recording acoustic data indicating defects in the pipeline using acoustic sensors of the device at block 502. The acoustic data provides information on pressure difference between pipeline and environment to indicate defects in the pipeline. Next, the method includes capturing visual data comprising images of internal defects of the pipeline using visual sensors of a device at block 504. Further, the method includes determining distance travelled by the device in the pipeline and number of bends in the pipeline using inertial measurement unit sensors (IMU). In the next step, the method includes correcting or minimizing an error generated by the inertial measurement unit sensors using an encoder at block 506. In some embodiments, the received sensor data may be stored in a memory unit 418 of the device for processing at a later stage. Finally, the method includes determining a final data based on the acoustic data, visual data, pipeline data indicative of defects in the inner surface of the pipeline at block 508. In various embodiments, the sensor data may be communicated to a server for generating a three dimensional map of the inner surface of the pipeline based on the mapped visual and acoustic data. The method enables detection of holes, leaks, cracks, pipe undulations, gas pockets, corrosion, blockages, pitting, or sedimentation.

[0043] According to another embodiment, a non-transitory computer readable medium having stored therein instructions encoded thereon executable by one or more processors for inspection of pipelines is disclosed herein. The instructions including communicating with a modular robotic device that propels through a pipeline, to capture data from one or more regions of interest. The communication interfaces may be wired and/or wireless communication technology. The instructions further include storing the inspection data in a memory unit or providing a real-time view of the internal structure of the pipeline. The instructions include processing the inspection data for determining the characteristics of the pipeline, generating a three dimensional map which reflects the internal view of the pipe and displaying the map of internal features of the pipe for inspection of the inner surface of the pipeline. In few embodiments, the instructions further include remotely controlling propulsion of the robotic device and to actively control direction of device motion for steering the device.

[0044] In some embodiments, the various functions described herein may be implemented using computer programming techniques including computer software, firmware, hardware or any combination thereof. The computer program product may be provided with the non-transitory computer readable medium having stored therein instructions that are executable by one or more processors, such that upon execution of instructions, the one or more processors perform the functions listed herein. The non- transitory computer readable media may be, but not limited to a portable computer diskette, a hard disk, optical storage device, magnetic storage device, a random access memory (RAM), a read-only memory (ROM), and/or any transmitting/receiving medium or other communication network or links.

[0045] Although the detailed description and the examples to follow contain many specifics, these should not be construed as limiting the scope of the invention but merely as illustrating different examples and aspects of the invention. It should be appreciated that the scope of the invention includes other embodiments not discussed herein. Various other modifications, changes and variations which will be apparent to those skilled in the art may be made in the arrangement, operation and details of the system and method of the present invention disclosed herein without departing from the spirit and scope of the invention as delineated in the appended claims.

[0046] EXAMPLES

[0047] The modular device was used for inspecting a pipeline with surface anomaly as illustrated in FIG. 5, according to one example of the present subject matter. The pipeline used in the experiment was 12 meters long and 8 inch pipe diameter with compressed air (as the pipeline fluid). The pipeline included 10 surface anomalies at regular intervals of 1 meter, wherein the size of the surface anomalies varied from 1 mm to 10 mm. This experiment is conducted at a pressure of 2 bars with leaks present at 6 meters from both the ends.

[0048] Further, the electronics modules used in the robotic device includes a raspberry pi 3 model B microprocessor, camera, audio card, microphone, 12V LED flash light, 5V lithium polymer battery, 12V lithium ion battery. Globus can withstand pressure of up to 8 bar, which was verified by conducting experiments at this pressure. To prevent leakage into the device, both the spherical dome and acrylic cylindrical connector were sealed using glue. A groove present on the spherical dome contains the sealant. The acrylic ring was press-fitted across the groove in both spherical casings to avoid the fluid leakage into the electronic modules. Furthermore, end caps are provided across the device to avoid the interaction of the fluid with the sensors and charging terminal. A spark proof adhesive is applied to every electronics components inside the device to prevent sparks. The components in device were assembled to ensure that there is very little oxygen inside the enclosure. A near vacuum environment reduced the possibility of sparking. The device was also encased with foam so that the noise accumulated due to self-rolling is minimized.

[0049] The modular robotic device was steered through the pipelines based on controls provided through a tether. The internal pipeline view recorded by the robotic device is illustrated in FIG. 6. The result illustrates the characterization of the inner surface anomaly. The acoustic emission data was plotted between amplitude (in decibel) versus frequency (in Hz) as illustrated in FIG. 7. As shown, the maximum amplitude was generated at 5.61 kHz. Further, the frequency increases with the decrease in hole/leak diameter at constant pressure. The frequency also increases with increase in fluid pressure for a particular hole/leak. The illustration represents an audio graph in the time domain. The spike signal strength also increased with increase in pressure and decrease in leak size. The robotic device also detected the surface anomalies with its visual inspection capability. By integrating the data from all the sensors on board, the robotic device was able to distinguish the anomalies like cracks, corrosion, pipe undulation, pitting and holes/leaks.

[0050] The disclosed robotic device is a passively propelled spherical robot that can be used for inspecting piggable and non-piggable pipelines, ferromagnetic and non ferromagnetic pipelines, which are widely used in industries. The device can operate without shutting down the entire plant. This allows inspectors to inspect a pipeline more frequently at a reduced cost. Further, the device is relatively simpler and easier to manufacture and use, and therefore, is inexpensive and has good market potential for inspection of pipelines especially for oil, gas, and water pipelines.

Claims

WE CLAIM:

1. A modular device (100), for visual and acoustic inspection of pipelines containing a moving fluid, the device comprising:

a transparent annulus (110) sealed between a pair of domes (102-A, 102-B) to form an outer shell of spherical or ellipsoidal shape;

a rotatable shaft (104) mounted about an axis of the outer shell and coupled to a pair of steering plates (106-A, 106-B), the steering plates configured to steer the device into a rotational motion along the fluid flow, wherein the shaft rotates independent of the outer shell;

a stabilization assembly (200) housed in the shell to dampen oscillations during motion, comprising: a mounting plate (108) attached to the shaft, wherein the mounting plate (108) is configured to maintain centre of mass of the device at a predetermined position;

a visual sensor (208) mounted on the mounting plate and configured to capture images of internal defects of the pipeline as visual data through the transparent annulus;

an acoustic sensor (114) configured to detect leaks using acoustic signals as acoustic data;

a processing unit (210) mounted on the mounting plate, wherein the processing units are configured to log the visual and acoustic data for inspection of the inner surface of the pipeline.

2. The device of claim 1, further comprising bearings or bushing (112) to couple the shaft (104) and the shell, wherein the bearings or bushing (112) enable rotation of the shell independent of rotation of the shaft.

3. The device of claim 1, wherein the stabilization assembly comprises at least one magnet.

4. The device of claim 1, wherein the mounting plate is further configured to mount plurality of batteries.

5. The device of claim 1, further comprising a communication unit configured to communicate the logged visual and acoustic data to a remote computing device, wherein the remote computing device generates a three-dimensional map of the inner surface of the pipeline.

6. The device of claim 1, wherein the stabilization assembly (200) further comprises inertial measurement unit, encoders, ultrasonic sensors, magnetic flux leakage sensors, magnetometers, or temperature sensors.

7. The device of claim 1, wherein the centre of mass is towards the bottom of the device.

8. The device of claim 1, wherein the device is connected to a remote system (420), wherein the remote system comprises at least a processing unit, a memory unit, and a network device.

9. A modular device (300) for visual and acoustic inspection of pipelines containing a moving fluid, the device comprising:

a remotely-controlled, motor-propelled first device (302);

a second device (304) connected to the first device through a chassis (306), the second device comprising:

an outer shell (316) comprising a pair of domes sealed to opposite ends of a transparent annulus; a rotatable shaft mounted about an axis of the outer shell, wherein the shaft rotates independently of the outer shell;

10. The device of claim 9, wherein the chassis (306) further comprises:

a frame (318) connecting the first device (302) and the second device (304), a spring-loaded telescopic rods (320) coupled to the frame (318), wherein the spring-loaded telescopic rod (320) is configured to transfer the propulsive force generated by the first device (302) to the second device (304), and

a steering mechanism configured to control the direction of device motion, wherein the steering mechanism comprises:

a servo motor (322), and

a servo arm (324) coupled to the servo motor (322) and the frame (318), wherein the servo arm (324) transfers the rotational motion from the servo motor (322) to the frame for changing the direction of the device motion.

11. The device of claim 9, wherein the first device comprises: an outer shell (308) comprising a pair of domes coupled with a rubber grip (310); and

an electric motor (312) controlled from a remote location.

12. The device of claim 9, wherein shaft of the electric motor is coupled to a hub of a wheel structure (326).

13. The device of claim 9, wherein the electric motor (312) is coupled to a tether (328) connected to a remote base location.

14. The device of claim 9, wherein an operator from the remote base location controls device motion via the tether (328).

15. The device of claim 9, wherein the second device (304) further comprises a communication unit configured to communicate the logged visual and acoustic data to a remote computing device, wherein the remote computing device generates a three- dimensional map of the inner surface of the pipeline.

16. A method for visual and acoustic inspection of pipelines containing a moving fluid, the method comprising:

recording, by acoustic sensors of a device, acoustic data indicating defects in the pipeline;

capturing, by visual sensors of the device, visual data comprising images of internal defects of the pipeline;

determining, by inertial measurement unit sensors (IMU) of the device, pipeline data based on distance travelled by the device in the pipeline and number of bends traversed in the pipeline;

correcting, by an encoder of the device, errors in the pipeline data; and determining, by a processing unit of the device, a final data based on the acoustic data, visual data, and pipeline data, indicative of defects in the inner surface of the pipeline.

17. The method of claim 16, wherein the sensor data is stored in a memory unit of the device for processing at a later stage.

18. The method of claim 16, wherein the final sensor data is communicated to a server for generating a three dimensional map of the inner surface of the pipeline.

19. The method of claim 16, wherein the acoustic data provides information on pressure difference between pipeline and environment to indicate defects in the pipeline.

20. The method of claim 16, wherein said defects comprise holes, leaks, cracks, pipe undulations, gas pockets, corrosion, blockages, pitting, or sedimentation.

21. The method of claim 16, wherein the pipeline is a non-ferromagnetic pipeline.