Patent Description:
A visual, mechanical, and/or electrical inspection and testing of a generator, electric motor, or turbomachine should be performed on a periodic basis. For example, generators may be inspected and tested periodically in the field for stator wedge tightness, visual surface anomalies, electromagnetic core imperfections, etc. Generator/stator inspection and testing procedures may require complete disassembly of the stator and removal of the generator rotor from the stator before any inspections or tests can be performed on the unit. The cost of disassembly and removal of the rotor, the time it takes for this process, and the dangers of rotor removal may impact the frequency of such inspections.

In situ inspection of generators has been performed employing poles, trolleys, scopes, and rotor turning techniques. These procedures may not accomplish the inspection task in a complete, timely, or safe manner.

Use of a robotic crawler capable of insertion through the radial air gap between the core iron and the retaining ring permits in situ inspection of the rotor and the stator core. The crawler may be inserted in a collapsed position into the gap and expanded by spring return pneumatic rams to the width of the air gap. The crawler may be remotely controlled by a technician and provides video cameras and other inspection tools to perform generator rotor and stator inspections within the air gap as the crawler is driven to selected locations. The crawler may be maneuvered by the technician within the air gap using video for both navigation and visual inspection.

A first aspect of this disclosure provides a system for in situ gap inspection. A robotic crawler has a plurality of multidirectional traction modules, an expandable body connected to the multidirectional traction modules, and a plurality of sensor modules positioned by the plurality of multidirectional traction modules. A control system is in communication with the robotic crawler. The control system provides a control signal to the robotic crawler to navigate an inspection path within an annular gap of a machine. Navigating the inspection path includes axial movement and radial movement of the plurality of multidirectional traction modules to inspect the annular gap using the plurality of sensor modules.

A second aspect of the disclosure provides a method for in situ gap inspection. A robotic crawler is inserted into an annular gap of a machine. An expandable body of the robotic crawler is expanded such that a plurality of multidirectional traction modules on the robotic crawler engage opposed surfaces in the annular gap. The robotic crawler traverses an inspection path within the annular gap using axial movements and radial movements. A plurality of inspection tests are performed along the inspection path using a plurality of sensor modules on the robotic crawler.

A third aspect of the disclosure provides a robot control system for in situ gap inspection. A crawler configuration module provides operating instructions for a robotic crawler having a plurality of multidirectional traction modules, an expandable body connected to the multidirectional traction modules, and a plurality of sensor modules. At least one inspection path definition correlates to an inspection path within an annular gap of a machine. The machine is selected from a generator, an electric motor, or a turbomachine. An autonomous navigation module is in communication with the robotic crawler to provide a control signal for the robotic crawler to traverse the inspection path using axial movements and radial movements of the plurality of multidirectional traction modules to inspect the annular gap using the plurality of sensor modules.

The illustrative aspects of the present disclosure are arranged to solve the problems herein described and/or other problems not discussed.

In the following description, reference is made to the accompanying drawings that form a part thereof, and in which is shown by way of illustration specific exemplary embodiments in which the present teachings may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present teachings and it is to be understood that other embodiments may be used and that changes may be made without departing from the scope of the present teachings. The following description is, therefore, merely illustrative.

Where an element or layer is referred to as being "on," "engaged to," "disengaged from," "connected to" or "coupled to" another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly engaged to," "directly connected to" or "directly coupled to" another element or layer, there may be no intervening elements or layers present.

Referring to <FIG>, an example system <NUM> for in situ gap inspection is shown. System <NUM> may include a robotic crawler <NUM>, a tether reel <NUM>, and a control unit <NUM>. Robotic crawler <NUM> may be configured to be inserted through an entrance gap into an annular gap in a machine to conduct autonomous or semi-autonomous inspection of the machine. For example, robotic crawler <NUM> may be a collapsible robot that can operate in a collapsed or expanded state and may be inserted through a narrow entrance gap in its collapsed state and expand to a wider gap width such that it engages the opposed surfaces of the annular gap. Robotic crawler <NUM> is shown in its expanded state in <FIG>. Once in the annular gap, robotic crawler <NUM> may navigate the annular gap and use one or more sensor modules to conduct various inspection tests during its movements or at various desired crawler positions in the annular gap. Robotic crawler <NUM> may be configured for multidirectional movement, including forward and reverse movement in the axial direction and bi-directional lateral movement in the radial direction. In some embodiments, robotic crawler <NUM> may be configured for omnidirectional movement that includes bi-directional movement in any orientation between the axial and radial directions, in addition to the axial and radial directions. For example, robotic crawler <NUM> may be configured to move in any direction in a <NUM> degree arc and freely change its direction of travel to any orientation in the <NUM> degree arc, including a plurality of directions between and angled from the axial and radial directions. In some embodiments, robotic crawler <NUM> may include a tether <NUM> connected to robotic crawler <NUM> and extending out of the machine during operation. For example, tether <NUM> may be a cable connected to robotic crawler <NUM> and enable retrieval of robotic crawler <NUM> in the event that robotic crawler <NUM> cannot navigate out of the annular gap under its own power. In some embodiments, tether <NUM> may provide a physical connection from robotic crawler <NUM> for a wired communication channel and/or a remote power source and/or pneumatic or hydraulic lines to support test systems or robotic operation. Tether reel <NUM> may be automated to adjust the tension and/or slack on tether <NUM> during operation of robotic crawler <NUM> within the annular gap, enabling robotic crawler <NUM> to navigate various navigation paths and perform inspection routines without a user manually managing the position of the tether. Control unit <NUM> may be in communication with robotic crawler <NUM> to provide control signals to robotic crawler <NUM> and receive sensor, navigation, and/or other operational data from robotic crawler <NUM>. In some embodiments, control unit <NUM> may be electrically connected to tether <NUM> directly or through tether reel <NUM> and the electrical connection may include one or both of a power channel and a communication channel. Control unit <NUM> may provide a user interface for a user to monitor, evaluate, supplement, and/or control robotic crawler <NUM> during an inspection deployment within the annular gap of the machine.

In some embodiments, robotic crawler <NUM> is a modular robot that may be reconfigured for different inspection tasks and enabling efficient maintenance, replacement, and/or upgrade of individual modules. Robotic crawler <NUM> may include a body frame, such as an expandable body <NUM>, for receiving, positioning, and connecting various modules relative to one another. In some embodiments, expandable body <NUM> accommodates a plurality of traction modules <NUM>, <NUM>, <NUM>. For example, robotic crawler <NUM> may include three traction modules <NUM>, <NUM>, <NUM>, a forward traction module <NUM>, a middle traction module <NUM>, and a rear traction module <NUM>, where forward traction module <NUM> and rear traction module <NUM> are configured to engage a first surface in the annular gap and the middle traction module <NUM> is configured to engage an opposed second surface in the annular gap. Traction modules <NUM>, <NUM>, <NUM> may be multidirectional traction module capable of moving robotic crawler <NUM> in multiple directions, including both axial and radial movement within the annular gap. Robotic crawler <NUM> may further include a plurality of sensor modules <NUM>, <NUM>, such as visual sensors for navigation and/or visual inspection. For example, sensor modules <NUM>, <NUM> may be attached via sensor interfaces on the forward and rear sides of middle traction module <NUM> and may provide both forward and rear facing navigation cameras, as well as one or more upward facing cameras for inspecting the adjacent surface of the annular gap. Robotic crawler <NUM> may also include one or more tether connectors <NUM>, <NUM> for detachably receiving tether <NUM>, generally with a compatible end connector <NUM> and fasteners <NUM>, <NUM>.

In some embodiments, tether reel <NUM> is an automated tether reel that may receive, release, and spool tether <NUM> to adjust tension as needed during operation of robotic crawler <NUM>. For example, tether reel <NUM> may include a servo motor <NUM> and tension management logic <NUM>. For example, servo motor <NUM> operating in a torque/current control mode may detect changes in tension on tether <NUM> as it enters tether reel <NUM> and tension management logic <NUM> may provide an algorithm for maintaining an acceptable tension range using servo motor <NUM> to reel in or reel out tether <NUM> under closed loop control. In some embodiments, tether <NUM> may have a fixed connection <NUM> to tether reel <NUM> and a separate wire <NUM> may connect to control unit <NUM>. For example, wire <NUM> may provide communication and/or power channels without providing the mechanical characteristics desired for tethering robotic crawler <NUM>. In some embodiments, tether reel <NUM> may provide an interface for receiving control signals for tether reel <NUM> from control unit <NUM>. For example, control unit <NUM> may be able to adjust tension control or motor parameters and/or manually override operation of tether reel <NUM>. In some embodiments, robotic crawler <NUM> may operate without a tether, carry its own power (e.g. batteries), and/or use wireless communication with control unit <NUM>.

In some embodiments, control unit <NUM> may include a computing system <NUM>. Computing system <NUM> may provide a plurality of programmatic controls and user interface for operating robotic crawler <NUM>. In some embodiments, computing system <NUM> is a general purpose computing devices, such as a personal computer, work station, mobile device, or an embedded system in an industrial control system (using general purpose computing components and operating systems). In some embodiments, computing system <NUM> may be a specialized data processing system for the task of controlling operation of system <NUM>. Computing system <NUM> may include at least one memory <NUM>, processor <NUM>, and input/output (I/O) interface <NUM> interconnected by a bus. Further, computing system <NUM> may include communication with external I/O device/resources and/or storage systems, including connected system, such as robotic crawler <NUM>, tether reel <NUM>, and network resources. In general, processor <NUM> executes computer program code, such as inspection control module <NUM>, that is stored in memory <NUM> and/or a storage system. While executing computer program code, processor <NUM> can read and/or write data to/from memory <NUM>, storage systems, and I/O devices (through I/O interface <NUM>). The bus provides a communication link between each of the components within computing system <NUM>. I/O devices may comprise any device that enables a user to interact with computing system <NUM> (e.g., keyboard, pointing device, display, etc.). Computing system <NUM> is only representative of various possible combinations of hardware and software. For example, the processor may comprise a single processing unit, or be distributed across one or more processing units in one or more locations, e.g., on a client and server. Similarly, memory and/or storage systems may reside at one or more physical locations. Memory and/or storage systems can comprise any combination of various types of non-transitory computer readable storage medium including magnetic media, optical media, random access memory (RAM), read only memory (ROM), etc. In some embodiments, computing system <NUM> is a laptop computer in communication with robotic crawler <NUM> via a wired (serial, USB, Ethernet, etc.) or wireless (<NUM>, Bluetooth, etc.) connection and running application software for system <NUM>. In some embodiments, some or all of the functions of computing system <NUM> may be on board robotic crawler <NUM> using an integrated computing system, such as an on board control module, with or without wireless communication to one or more user interfaces and/or remote data storage.

In some embodiments, computing system <NUM> may include one or more application programs, data sources, and/or functional modules for controlling robotic crawler <NUM>. For example, computing system <NUM> may include inspection control module <NUM> that operates in conjunction with data sources <NUM>, <NUM>, <NUM>, <NUM> to provide control signals to and receive data from robotic crawler <NUM>. Inspection control module <NUM> may provide a visual display module <NUM>. For example, visual data collected by cameras on robotic crawler <NUM> may be displayed by visual display module <NUM>, such as a graphical user interface for one or more video feeds. In some embodiments, visual data from robotic crawler <NUM> may be stored in visual data source <NUM> for use by visual display module <NUM> and/or selective, temporary, and/or archival storage of visual data for later use, including use by other users or systems. Data display module <NUM> may provide display, including visual display, of other test data, including processed visual data and resulting calculations or analysis. For example, data display module <NUM> may include a graphical user interface for test results from one or more test protocols using sensor and navigation data from robotic crawler <NUM>. In some embodiments, test data from robotic crawler <NUM> may be stored in test data source <NUM> for use by data display module <NUM> and/or selective, temporary, and/or archival storage of test data for later use, including use by other users or systems. Data display module <NUM> may include a real-time display of test data as it is collected by robotic crawler <NUM> and/or one or more functions for viewing, aggregating, analyzing, visualizing, selecting, and/or reporting test data from test data source <NUM>. Autonomous navigation module <NUM> may provide a protocol or series of commands for navigation of robotic crawler <NUM> within the annular gap of the machine. In some embodiments, autonomous navigation module <NUM> enables a user to select an inspection path from a plurality of inspection paths stored in inspection path data source <NUM>. For example, inspection paths may be defined as physical paths robotic crawler <NUM> should follow within the annular gap to complete one or more inspection tasks in one or more locations within the annular gap. Inspection paths may be based on a physical schematic or parameters of one or more machines defining axial and radial distances. Inspection paths may also include parameters and locations related to specific features of interest for either navigation (e.g., surface features to be avoided) or for testing (e.g., locations or corresponding crawler positions for conducting specific tests). In some embodiments, inspection paths may be stored and defined in terms of a sequence of crawler commands. Autonomous navigation module <NUM> may enable autonomous navigation by robotic crawler <NUM> receiving and executing a sequence of crawler commands without user intervention once the autonomous operation initiated. In some embodiments, autonomous navigation module <NUM> may have completely autonomous inspection routines that require no user intervention once initiated or may include a plurality of inspection subroutines, such as specific movement patterns, position changes, or test protocols, that are initiated in a desired sequence by a user, potentially based on navigational, visual, or test data feedback. Manual navigation module <NUM> may provide a user with the ability to pilot or otherwise control robotic crawler <NUM>. In some embodiments, manual navigation module <NUM> may be provided for establishing an initial position for initiating automated control and/or allow a user to override automated control in response to problems, exceptions, or specific test protocols (such as an initial test result that requires further data gathering). In some embodiments, control unit <NUM> may include one or more user I/O interfaces for manually controlling robotic crawler <NUM>, such as joysticks and other tactile controls, for navigation, deploying sensors, and conducting various test protocols. Inspection module <NUM> may provide a plurality of routines for various inspection protocols using one or more sensor modules. In some embodiments, one or more sensor protocols are stored in sensor protocol data source <NUM> for use by inspection module <NUM>. For example, a visual inspection protocol may include activating and capturing visual data from one or more sensor modules on robotic crawler <NUM> along a defined navigation path to enable mapping of captured visual data to location information with the machine. In some embodiments, a plurality of cameras with varying facings and/or positionable cameras may be present in one or more sensor modules and a visual inspection module may include selective activation and positioning of robotic crawler <NUM> and its various cameras. An inspection protocol executed by inspection module <NUM> may include a combination of navigational elements (navigation path, autonomous positioning, and/or manual positioning) and sensor protocols (position requirements, deployment, activation, timing/sampling, parameters, etc.). In some embodiments, inspection module <NUM> may define the storage of visual data and test data in visual data source <NUM> and test data source <NUM> and/or the display of visual data by visual display module <NUM> and test data by data display module <NUM>. Crawler configuration module <NUM> may provide data regarding the configuration of modules and related capabilities and protocols for any given configuration of robotic crawler <NUM>. In some embodiments, crawler configuration module <NUM> may map crawler configurations to machine specifications and sensor protocols to assist a user in matching inspection protocols with the resources available for a given test deployment. For example, a given configuration of sensor modules may define the test capabilities of robotic crawler <NUM> and recommend specific inspection protocols to utilize those sensor modules. In some embodiments, crawler configuration module <NUM> may include a library of sensor modules and related capabilities and support user reconfiguration of robotic crawler <NUM> for a desired inspection protocol. Crawler configuration module <NUM> may also define the set of crawler commands <NUM> that may be used to control robotic crawler <NUM>. Crawler coordination module <NUM> may enable inspection control module <NUM> to control more than one robotic crawler <NUM> simultaneously. In some embodiments, crawler coordination module <NUM> may maintain a plurality of communication channels for control signals and data signals with a plurality of robotic crawlers. For example, crawler coordination <NUM> may manage a plurality of instances of visual display module <NUM>, data display module <NUM>, autonomous navigation module <NUM>, manual navigation module <NUM>, inspection module <NUM>, and crawler configuration module <NUM> for parallel management of the plurality of robotic crawlers. In some embodiments, crawler coordination module <NUM> may include interference protection for tracking the current crawler positions, navigation paths, and timing of various movements and sensor protocols to prevent collisions or other interference within the annular gap.

In some embodiments, visual display module <NUM>, data display module <NUM>, autonomous navigation module <NUM>, manual navigation module <NUM>, and inspection module <NUM> may include issuing one or more crawler commands <NUM> to robotic crawler <NUM> to complete some aspect of their function. Crawler commands <NUM>. may then be translated into messages or control signals from control unit <NUM> to robotic crawler <NUM>. In some embodiments, crawler configuration module <NUM> may define the set of crawler commands available to the other modules based on the configuration of robotic crawler <NUM>. An example set of crawler commands <NUM>. are provided, but will be understood to be neither exclusive nor exhaustive of the possible crawler commands that could be used to control robotic crawler <NUM> and various configurations of traction modules, sensor modules, and body frame mechanics possible. Robotic crawler <NUM> may receive expand/contract commands <NUM> to expand or contract expandable body <NUM> between a collapsed state and one or more expanded states, such as a control signal to one or more motors that drive the body position. In some embodiments, expand or contract may be based on feedback from sensors within robotic crawler <NUM> when the traction modules are in a planar position (for collapsed state) or have contacted opposed surfaces in the annular gap (for expanded state). In other embodiments, expand or contract may be based on time (e.g. activate motor for x seconds of expansion or contraction) or distance (e.g., set crawler width to y inches). Robotic crawler <NUM> may receive move commands <NUM> to drive its traction modules forward or backwards (based on the present alignment of the traction modules in the case of multidirectional traction modules). Robotic crawler <NUM> may receive change direction commands <NUM> to reorient its traction modules and direction of travel. For example, change direction commands <NUM> may allow multidirectional traction modules to rotate <NUM> degrees and change from axial orientation and directions of travel to radial orientation and directions of travel. In some embodiments, change direction commands <NUM> may include orientation changes of greater or less than <NUM> degrees and include a feedback signal for confirming orientation or traction modules and communicating orientation back to control unit <NUM>. Robotic crawler <NUM> may receive traction mode commands <NUM> to drive changes in the configuration of the traction modules for different traction modes. For example, traction modules may include a flat mode for robot insertion and/or low profile and smooth surface travel and a clearance mode for providing clearance between the body of robotic crawler <NUM> and the surfaces it is moving along and/or traversing obstacles or uneven surfaces. Traction mode commands <NUM> may include control signals to change from flat mode to clearance mode or from clearance mode to flat mode. Robotic crawler <NUM> may receive position sensor commands <NUM> for sensor modules that include deployment and/or positioning features. For example, some sensor modules may include electromechanical features for extending, raising, lowering, rotating, or otherwise positioning one or more elements of the sensor module before, during, or after data collection. Position sensor commands <NUM> may include a control signal to activate a motor for extending or otherwise repositioning a sensor from robotic crawler <NUM> to position it for data collection or for moving a sensor (such as by rotation) independent of changing crawler position during data collection. Robotic crawler <NUM> may receive acquire data commands <NUM> for initiating data collection through a sensor module using whatever modality is present in that sensor module. Acquire data commands <NUM> may provide a start or stop signal for a continuous data collection mode, such as a video feed from the camera(s) of a visual sensor, or a specific test sequence for a more discrete sensor test, such as a mechanical wedge tightness test. It will be understood that some robotic crawlers and control units may be able to communicate and manage multiple commands in parallel, as overlapping sequences, or as serial command series. Crawler coordination module <NUM> may enable control unit <NUM> to issue commands to and acquire data from multiple robotic crawlers in parallel.

Referring to <FIG>, an in situ gap inspection system <NUM> is shown with a robotic crawler <NUM>, such as robotic crawler <NUM> in <FIG>, being inserted into a machine <NUM>. Machine <NUM> may be any machine with an annular gap <NUM> accessible through an entrance gap <NUM> and, more specifically, a variety of machine configurations of generators, electric motors, or turbomachines. For example, a generator may allow insertion through the radial air gap between the core iron and the retaining ring permits in situ inspection of the rotor and the stator core. Annular gap <NUM> may be defined between a cylindrical central member <NUM> and a surrounding cylindrical member <NUM> with generally complementary curvature. In some embodiments, annular gap <NUM> may be an air gap generally defined by: (the inner diameter of the stator minus the outer diameter of the rotor) divided by two. Annular gap <NUM> has an axial length from a first end to a second end of cylindrical central member <NUM> and a circumference measured radially around the circumference of cylindrical central member <NUM>. Annular gap <NUM> has an annular gap width <NUM> measured from outer surface <NUM> of cylindrical central member <NUM> to the nearest opposite surface (inner surface <NUM>) of surrounding cylindrical member <NUM>. In some embodiments, entrance gap <NUM> may be an air gap at an end of the central cylindrical member <NUM> and have the same entrance width as annular gap width <NUM>. In other embodiments, entrance gap <NUM> may include additional features, such as a retaining member <NUM>, that further constrain entrance gap <NUM> and define an entrance gap width <NUM> is that is less than annular gap width <NUM>. In some embodiments, additional features or obstacles may reduce annular gap width <NUM>, such entrance baffles used to direct cooling air flow.

In <FIG>, robotic crawler <NUM> is in a collapsed state, where its traction modules are aligned in a single plane. Robotic crawler <NUM> is shown outside entrance gap <NUM> before insertion and inside annular gap <NUM> after insertion. Robotic crawler <NUM> may define a collapsed crawler width <NUM>. Collapsed crawler width <NUM> may be less than both entrance gap width <NUM> and annular gap width <NUM>. In its collapsed state, robotic crawler <NUM> engages only outer surface <NUM> of central cylindrical member <NUM> inside annular gap <NUM>.

<FIG> show two views of robotic crawler <NUM> in an expanded state within annular gap <NUM>. \\Then robotic crawler <NUM> is in its expanded state, it may engage opposed surfaces <NUM>, <NUM>. In an expanded state, robotic crawler <NUM> may define an expanded crawler width <NUM>. Expanded crawler width <NUM> may be larger than collapsed crawler width <NUM> and entrance gap width <NUM>, and equal to annular gap width <NUM> such that surface contact may be maintained with opposed surfaces <NUM>, <NUM>. In some embodiments, robotic crawler <NUM> comprises a plurality of traction modules <NUM>, <NUM>, <NUM> mounted in an expandable body <NUM>. Traction modules <NUM>, <NUM> may engage only outer surface <NUM> of central cylindrical member <NUM> and traction module <NUM> may engage only inner surface <NUM> of surrounding cylindrical member <NUM>. In some embodiments, the configuration of traction modules <NUM>, <NUM>, <NUM> may be reversed and traction modules <NUM>, <NUM> may engage only inner surface <NUM> of surrounding cylindrical member <NUM> and traction module <NUM> may engage only outer surface <NUM> of central cylindrical member <NUM>. Traction modules <NUM>, <NUM>, <NUM> may include rollers, including wheels, balls, or tracks, to move robotic crawler <NUM> through annular gap <NUM> based on moving surface contact with opposed surfaces <NUM>, <NUM>. Traction modules <NUM>, <NUM>, <NUM> may move robotic crawler <NUM> on a desired navigation path through annular gap <NUM>.

Referring to <FIG>, another embodiment of a robotic crawler <NUM> is shown in an annular gap <NUM> with lines <NUM>, <NUM> showing example navigation paths for inspecting annular gap <NUM>. Robotic crawler <NUM> is shown in an expanded state in a starting crawler position just inside entrance gap <NUM> adjacent an entrance end portion <NUM> of the machine <NUM>. Following line <NUM>, robotic crawler <NUM> moves in a forward axial direction along a gap length <NUM> of annular gap <NUM> from the entrance end portion <NUM> to the closed end portion <NUM>. In some embodiments, robotic crawler <NUM> may reach a step or other obstacle representing the end of the navigable gap length <NUM> of annular gap <NUM>. For example, closed end portion <NUM> may include a step created by a retaining ring or other feature and may include another air gap into an enclosed end region of the machine. Robotic crawler <NUM><NUM> may include multidirectional traction modules that enable it to change its travel direction from the axial direction to the radial direction. Line <NUM> shows a number of radial steps along the circumference of annular gap <NUM>. The length of the radial step may depend on a variety of factors related to sensor range/area (or field of view for visual sensors), test locations, desired test coverage or sampling, and/or specific machine features to be included in the navigation path to support desired test protocols using the sensor modules on robotic crawler <NUM>. After a new radial position is achieved, line <NUM> shows a return path in the reverse axial direction along gap length <NUM>. Robotic crawler <NUM> may reorient its movement direction back to an axial orientation and move in the opposite direction down the length of annular gap <NUM>. In some embodiments, robotic crawler <NUM> may reach a step or other obstacle associated with entrance gap <NUM> and representing the end of the navigable gap length <NUM> of annular gap <NUM>. Robotic crawler <NUM> may again reorient its travel direction for radial movement and make another radial step. Robotic crawler <NUM> may continue stepping through these axial passes at various radial positions along the circumference for the area of annular gap <NUM> to be inspected with the selected sensor modules and inspection protocol. In some embodiments, robotic crawler <NUM> may traverse gap length <NUM> in radial positions providing overlapping coverage for visual inspection around the entire circumference of annular gap <NUM> to provide a complete visual inspection of the surfaces of annular gap <NUM>. Following line <NUM> shows an alternate inspection path and is provided to demonstrate that a plurality of inspection paths may be enabled by multidirectional and omnidirectional movement. Line <NUM> takes robotic crawler <NUM> along an inspection path that includes axial travel, radial travel, and travel along intermediate orientations between the axial and radial directions. More complex and less repetitious inspection paths may be used for inspection of specific areas or features, as well as to navigate around known obstacles.

Referring to <FIG>, an additional embodiment of a robotic crawler <NUM> is shown in several views and including an expanded state in <FIG> and a collapsed state in <FIG>. In some embodiments, robotic crawler <NUM> is a modular robot with an expandable body <NUM> including plurality of frames <NUM>, <NUM>, <NUM> for accommodating removable modules. Removable modules may include traction modules <NUM>, <NUM>, <NUM> that provide rollers, such as wheels, tracks, or balls, or another form of locomotion for moving robotic crawler <NUM> along the surfaces within a gap. Robotic crawler <NUM> may also accommodate a plurality of sensor modules, such as navigation sensors, visual inspection sensors, structural test sensors, or electrical test sensors, using sensor interfaces that provide mechanical and/or electrical/communication/control between robotic crawler <NUM> and the sensor modules. For example, one or more module frames may include sensor interfaces and/or the traction modules or other sensor modules may include sensor interfaces for chaining multiple modules from a single frame. The plurality of sensor interfaces may be provided at several positions on robotic crawler <NUM> to provide different operating positions for various sensors. For example, each of traction modules <NUM>, <NUM>, <NUM> may include one or more sensor interfaces and related sensor positions. In some embodiments, there may be multiple configurations of sensor interfaces. For example, sensor interfaces for attachment to traction modules <NUM>, <NUM>, <NUM> may be different than sensor interfaces between serial sensor interfaces. Other modules may also be provided for other functions, such as a tether connector module <NUM>.

In some embodiments, expandable body <NUM> includes generally rectangular base frame and includes lateral members <NUM>, <NUM> on the long sides of the rectangle, connected to front frame <NUM> and rear frame <NUM> providing the short sides of the rectangle. Lateral members <NUM>, <NUM> may include frame attachments <NUM>, <NUM>, <NUM>, <NUM> proximate their respective distal ends. Frame attachments <NUM>, <NUM> may connect to front frame <NUM> and frame attachments <NUM>, <NUM> may connect to rear frame <NUM>. In some embodiments, middle frame <NUM> may be configured to be displaced from the plane of front frame <NUM> and rear frame <NUM> to expand the width of expandable body <NUM> in its expanded state. Middle frame <NUM> may be attached to extension link members <NUM>, <NUM>, which are connected to the rectangular base frame. For example, extension link members <NUM>, <NUM> may include pivoting attachments <NUM>, <NUM>, <NUM>, <NUM> with front frame <NUM> and rear frame <NUM> or, alternately, with lateral members <NUM>, <NUM> proximate their distal ends. Extension link members <NUM>, <NUM> may be articulated link members with first links <NUM>, <NUM> and second links <NUM>, <NUM> having pivoting attachments <NUM>, <NUM> to middle frame <NUM>. Pivoting attachments <NUM>, <NUM> may act as an articulated joint in extension link members <NUM>, <NUM> and move middle frame <NUM> perpendicular to the plane of the rectangular base frame. Expandable body <NUM> may include a motor or other actuator for moving middle frame <NUM>. For example, lateral members <NUM>, <NUM> may include linear actuators <NUM>, <NUM> for moving front frame <NUM> relative to rear frame <NUM>, changing the lengths of lateral members <NUM>, <NUM> and the distance between front frame <NUM> and rear frame <NUM>. When lateral members <NUM>, <NUM> are in their fully extended positions, front frame <NUM>, middle frame <NUM>, and rear frame <NUM> may be in the same plane and expandable body <NUM> is in its narrowest or collapsed state. As lateral members <NUM>, <NUM> are shortened by linear actuators <NUM>, <NUM> and rear frame <NUM> moves toward front frame <NUM>, extension link members <NUM>, <NUM> articulate at pivoting attachments <NUM>, <NUM> and first links <NUM>, <NUM>, second links <NUM>, <NUM>, and lateral members <NUM>, <NUM> form an isosceles triangle with middle frame <NUM> moving in a direction perpendicular to the direction of movement between front frame <NUM> and rear frame <NUM>. Other configurations of expandable bodies are possible, such as one or more frames being mounted on lever arms, scissor jacks, telescoping members, or other displacement mechanisms. In some embodiments, expandable body <NUM> may incorporate shock absorbers between front frame <NUM> and rear frame <NUM> and middle frame <NUM> to assist in navigating uneven gap spaces. For example, extension link members <NUM>, <NUM> may incorporate telescoping links with an internal spring to assist with traction on opposed gap surfaces and compensate for some obstacles and/or changes in gap spacing. In some embodiments, lateral members <NUM>, <NUM> may include emergency releases <NUM>, <NUM> to disengage lateral members <NUM>, <NUM> manually in the event of power loss or other failure that prevents control of linear actuators <NUM>, <NUM>. For example, frame attachments <NUM>, <NUM> may incorporate mechanical fasteners that attach lateral members <NUM>, <NUM> to frame attachments <NUM>, <NUM> and these mechanical fasteners may act as emergency releases <NUM>, <NUM> by enabling a user to release the mechanical fasteners and thereby disengage lateral members <NUM>, <NUM> to cause expandable body <NUM> to collapse into its collapsed state. In some embodiments, emergency releases <NUM>, <NUM> may be screws, bolts, or pins through frame attachments <NUM>, <NUM> and into lateral members <NUM>, <NUM> that may be removed to collapse expandable body <NUM>. In some embodiments, expandable body <NUM> has a lateral shape that is an arc based on the configuration of frames <NUM>, <NUM>, <NUM> and lateral members <NUM>, <NUM>, most visible in <FIG>. The arc of expandable body <NUM> may be configured to complement the curvature of an annular gap in which robotic crawler <NUM> is intended to operate. For example, the arc or curvature may be similar to the arc of the outer surface of the central cylindrical member or the inner surface of the surrounding cylindrical member that define the annular gap.

In some embodiments, each of frames <NUM>, <NUM>, <NUM> are configured to receive, position, and retain traction modules <NUM>, <NUM>, <NUM>. For example, traction modules <NUM>, <NUM>, <NUM> may each be multidirectional traction modules with fixed outer frames <NUM>, <NUM>, <NUM> to removably attach to frames <NUM>, <NUM>, <NUM>. Traction modules <NUM>, <NUM>, <NUM> may include rotating inner frames <NUM>, <NUM>, <NUM> that enable robotic crawler <NUM> to change the orientation of rollers <NUM>, <NUM>, <NUM> and direction of movement. Each of traction modules <NUM>, <NUM>, <NUM> may also include one or more interfaces <NUM>, <NUM>, <NUM>, <NUM> that may be used to attach sensor modules or other functional modules, directly or in series. For example, traction module <NUM> may include interface <NUM> and is shown with a visual sensor module <NUM>. Traction module <NUM> may include interfaces <NUM>, <NUM> and visual sensor modules <NUM>, <NUM>. Traction module <NUM> may include interface <NUM>, visual sensor module <NUM>, and tether connector module <NUM>.

<FIG> shows an example multidirectional traction module <NUM> according to various embodiments. Traction module <NUM> may be configured for use in a robotic crawler, such as robotic crawlers <NUM>, <NUM>, <NUM>, <NUM>. Traction module <NUM> enables the direction and orientation of travel of a robotic crawler to be changed without changing the orientation of the robotic crawler itself. Traction module <NUM> may include a fixed outer frame <NUM> with one or more attachment features <NUM>, <NUM> configured for attachment to a robotic crawler, such as insertion into a body frame. In some embodiments, traction module <NUM> may also include an electrical interconnect <NUM> for power and/or control signals from the robotic crawler to traction module <NUM>. Traction module <NUM> may include a rotating frame <NUM> seated within fixed outer frame <NUM> and capable of rotational movement relative to fixed outer frame <NUM>. For example, rotating frame <NUM> or fixed outer frame <NUM> may include an actuator <NUM>, such as a motor and worm gear from for moving rotating frame <NUM>. In some embodiments, rotating frame <NUM> may rotate <NUM> degrees to change the orientation and direction of travel. In some embodiments, rotating frame <NUM> may traverse or be stopped in various positions or orientations along at least a <NUM> degree arc and/or up to a <NUM> degree arc. In some embodiments, the worm gear or other drive mechanism incorporates an encoder to measure the angular position or orientation of rotating frame <NUM>. For example, reference arcs <NUM>, <NUM> may provide visual reference through reflective and non-reflective coatings to allow and optical sensor to ascertain the orientation of traction module <NUM>. Rotating frame <NUM> may provide a first position corresponding to forward and/or reverse (which may generally correspond to the axial direction within an annular gap). In some embodiments, roller assembly <NUM> is disposed within rotating frame <NUM> and includes a configuration of rollers <NUM>, <NUM> for providing rotating traction to move the robotic crawler in a direction of rotation. Roller assembly <NUM> may also include a motor or other actuator for rotating rollers <NUM>, <NUM>. In some embodiments, roller assembly <NUM> may be driven in a forward or reverse direction in addition to changes in orientation from rotation of rotating frame <NUM>. In some embodiments, rollers <NUM>, <NUM> may engage and rotate belts <NUM>, <NUM> to provide traction for traction module <NUM>. For example, belts <NUM>, <NUM> may substantially cover the length of rollers <NUM>, <NUM> to provide a large contact area with adjacent machine surfaces. In some embodiments, belts <NUM>, <NUM> may include surface features or treatments to improve traction, such as a textured surface for providing grip on oily surfaces. In some embodiments, roller assembly <NUM> may include a roller configuration actuator <NUM> to support multiple traction configurations and mechanisms for changing between configurations and locking the selected configuration in place. For example, roller assembly <NUM> may be capable of switching between a flat mode to provide a lower profile and an obstacle or clearance mode with angled belt paths for increasing the clearance between the robotic crawler and the surfaces it is traveling on. Roller configuration actuator <NUM> may actuate the change between the two modes and provide a locking mechanism for holding each configuration. In some embodiments, roller configuration actuator <NUM> may incorporate emergency releases <NUM>, <NUM> that may be actuated to return roller assembly <NUM> to the flat mode in the event of a power failure or other loss of control of roller configuration actuator <NUM>.

<FIG> show roller assembly <NUM> in flat mode (<FIG>) and clearance mode (<FIG>) and roller configuration actuator <NUM> (<FIG>) for maintaining the two modes. Roller assembly <NUM> may have rollers <NUM>, <NUM>, <NUM>, <NUM> in paired axel assemblies <NUM>, <NUM>. Axel assemblies <NUM>, <NUM> may be rotatable around central pivot attachments <NUM>, <NUM> to adjust between flat mode and clearance mode. In flat mode, each axis of rotation of rollers <NUM>, <NUM>, <NUM>, <NUM> may be aligned in a single plane <NUM>. In clearance mode, axel assemblies <NUM>, <NUM> rotate rollers <NUM>, <NUM>, <NUM>, <NUM> out of the shared plane and define at least two distinct planes <NUM>, <NUM>, <NUM>, <NUM> of operation. For example, plane <NUM> aligns with the axis of rotation of rollers <NUM>, <NUM> which support a parallel return path for belts <NUM>, <NUM>. Plane <NUM> aligns with axis of rotation of rollers <NUM>, <NUM>, which support a primary traction path for belts <NUM>, <NUM>. Plane <NUM> is distinct from plane <NUM>. Plane <NUM> aligns with axis of rotation of rollers <NUM>, <NUM> (on axel assembly <NUM>) which supports a first climbing traction surface or return path (depending on the direction of travel). Plane <NUM> aligns with axis of rotation of rollers <NUM>, <NUM> (on axel assembly <NUM>) which supports a second climbing traction surface or return path (depending on the direction of travel). Once rollers <NUM>, <NUM>, <NUM>, <NUM> are rotated out of common plane <NUM>, a reaction force between the adjacent machine surface and primary traction surface may encourage reverse rotation to return to flat mode and a locking mechanism <NUM> may be included within roller configuration actuator <NUM> to counteract this tendency. In some embodiments, locking mechanism <NUM> may include ratchet ends <NUM>, <NUM> on pivot attachments <NUM>, <NUM> with claw members <NUM>, <NUM> to engage ratchet ends <NUM>, <NUM> and hold them in place in clearance mode under tensioning force from spring <NUM>. A powered release mechanism <NUM> may be provided to controllably supply an opposing force to the tensioning force from spring <NUM>. For example, a shape memory alloy wire <NUM> between two lever arms <NUM>, <NUM> may contract when heated to release ratchet ends <NUM>, <NUM> and allow roller assembly <NUM> to return to flat mode. An electric solenoid or other actuator may provide a similar powered release mechanism <NUM>. Locking mechanism <NUM> may include manual emergency releases <NUM>, <NUM>. For example, emergency releases <NUM>, <NUM> may be openings that provide access to manual release levers <NUM>, <NUM> incorporated into locking mechanism <NUM> for holding roller assembly <NUM> in obstacle or clearance mode. In some embodiments, a pin or similar tool is guided manually into the openings of emergency releases <NUM>, <NUM> to actuate manual release levers <NUM>, <NUM>. Other configurations for manually actuating emergency releases <NUM>, <NUM> may include spring loaded buttons, spring pins, levers, or similar actuator members.

Referring to <FIG>, a cross-section view of an example connecting link <NUM>, such as may be used for first links <NUM>, <NUM> or second links <NUM>, <NUM>, and incorporating a shock absorber is shown. Connecting link <NUM> may include a first telescoping member portion <NUM> and a second telescoping member portion <NUM> held in movable relation to one another by a spring <NUM>. Note that other configurations of compactible but resistive link members are possible, including the use of pneumatic, fluid, or magnetic resistance between rigid members and/or the use of one or more flexible members. The force necessary to compact spring <NUM> and shorten connecting link from its resting or maximum length to a compacted length may be configured by adjusting the spring constant and/or frictional forces resisting such displacement. In some embodiments, connecting link <NUM> may include a displacement transducer <NUM> or other sensor for detecting the change in length of connecting link <NUM>. Displacement transducer <NUM> may generate a signal indicative of the length change and communicate that signal to the robotic crawler or a control unit for the robotic crawler. In some embodiments, displacement transducer <NUM> will be mated with a wireless communication subsystem for providing sensor data. In some embodiments, displacement transducer <NUM> will have a wired connection to a data bus for sensor and other operational data within a robotic crawler. In some embodiments, displacement data from displacement transducer <NUM> may be used to adjust the distance of the expanded state of the robotic crawler to compensate for changes in gap width or particular obstacles.

Referring to <FIG>, an example configuration of visual sensor modules, including navigation modules, visual inspection modules, and combinations thereof, is shown on a robotic crawler <NUM> in a gap <NUM> between opposed machine surfaces <NUM>, <NUM>. Robotic crawler <NUM> may include a front traction module <NUM>, a middle traction module <NUM>, and a rear traction module <NUM> that provide positioning and a sensor interface for the visual sensor modules. In <FIG>, a combination of four sensor modules <NUM>, <NUM>, <NUM>, <NUM> is shown. Sensor module <NUM> may be a visual inspection module including a plurality of cameras and connected to front traction module <NUM>. Sensor module <NUM> may have a first surface field of view <NUM>, a second surface field of view <NUM>, and a gap field of view <NUM>. Sensor modules <NUM>, <NUM> may be navigation sensor modules including single cameras oriented in the direction of travel, both being connected to middle traction module <NUM>. Sensor module <NUM> may have a gap field of view <NUM> in one (axial) direction and sensor module <NUM> may have a gap field of view <NUM> in an opposite (axial) direction. Sensor module <NUM> may be an auxiliary sensor module with a single camera connected to rear traction module <NUM>. An auxiliary sensor module may accommodate another function, such as tether attachment or another type of test sensor, while still incorporating at least one camera for collecting visual data. Sensor module <NUM> may have a gap field of view <NUM> to the rear of the robotic crawler. In an alternate embodiment, sensor module <NUM> is another visual inspection module including a plurality of cameras, but only one camera is active for auxiliary navigation while sensor module <NUM> is being used for the primary inspection protocol.

Referring to <FIG>, an example navigation sensor module <NUM> is shown. In some embodiments, navigation sensor module <NUM> includes a module housing <NUM> defining a mounting interface <NUM> and accommodating fasteners <NUM>, <NUM> for removably attaching navigation sensor module <NUM> to a robotic crawler. Mounting interface <NUM> is configured for removable attachment to a sensor interface on a robotic crawler, such as a sensor interface on a module mounting frame or a previously installed module, including a traction module with a sensor interface. In some embodiments, module housing <NUM> may include electronics, power source, communication channels, and/or optics for one or more visual sensors or cameras. In some embodiments, mounting interface <NUM> may include a connector for power and/or communication channels for control and/or data signals to and from navigation sensor module <NUM>. Navigation sensor module <NUM> may include a visual sensor for providing navigation data to a robotic crawler and/or control unit. In some embodiments, navigation sensor module <NUM> includes a camera <NUM> mounted to or embedded in module housing <NUM>. For example, camera <NUM> may be a forward mounted video camera with a single aperture to gather visual data in the direction it is aligned with (such as forward or backward in a gap space). In some embodiments, camera <NUM> may incorporate a protective housing and/or include one or more components mounted inside module housing <NUM>. In some embodiments, camera <NUM> may be mounted on a movable mounting that enables the field of view direction of camera <NUM> to be adjusted relative to the position of navigation sensor module <NUM> and the robotic crawler to which it is attached. For example, a movable mount may provide one or more pivoting adjustments that enable a user to change and set the direction of camera <NUM> prior to insertion in a gap. Another movable mount may include powered adjustments that are configured for remote control through a sensor control bus in the robotic crawler or wireless communication with the robotic crawler and/or control unit, enabling the field of view to be changed during operation of the robotic crawler within the gap of the machine. Camera <NUM> may include other adjustable parameters, such as focus, aperture size, frame rates, and other settings for controlling visual data quality (or quantity). In some embodiments, navigation sensor module <NUM> may include on or more light sources to improve visibility with camera <NUM>. In some embodiments, alternate navigation sensors may be used, including cameras with sensors for ultraviolet or infrared spectrums or other location technologies (e.g. sonar, RF beacons, magnetic imaging, etc.).

Referring to <FIG>, bottom and top views of an example visual inspection module <NUM> are shown. Visual inspection module <NUM> includes a module housing <NUM> defining a mounting interface <NUM> and accommodating fasteners <NUM>, <NUM> for removably attaching visual inspection module <NUM> to a robotic crawler. Mounting interface <NUM> is configured for removable attachment to a sensor interface on a robotic crawler, such as a sensor interface on a module mounting frame or a previously installed module, including a traction module with a sensor interface. In some embodiments, module housing <NUM> may include electronics, power source, communication channels, and/or optics for one or more visual sensors or cameras. In some embodiments, mounting interface <NUM> may include a connector for power and/or communication channels for control and/or data signals to and from visual inspection module <NUM>. Visual inspection module <NUM> may include a plurality of visual sensors for providing visual data to a robotic crawler and/or control unit. In some embodiments, visual inspection module <NUM> includes cameras <NUM>, <NUM>, <NUM> mounted to or embedded in module housing <NUM>. For example, camera <NUM> may be a video camera oriented toward a first surface within a machine gap to gather visual data from the first surface as the robotic crawler moves along that surface. Cameras <NUM>, <NUM> may be video cameras oriented toward a second surface opposite the first surface within the machine gap to gather visual data from the second surface as the robotic crawler moves along that surface. In some embodiments, cameras <NUM>, <NUM>, <NUM> may be recessed inside module housing <NUM> to prevent clearance issues with an adjacent machine surface. In some embodiments, cameras <NUM>, <NUM>, <NUM> may include a variety of controls for position/direction of view, focus, field width, aperture size, frame rates, and other settings for controlling visual data quality (or quantity). Some or all of these adjustments may be manually set outside of the machine and/or are configured for remote control through a sensor control bus in the robotic crawler or wireless communication with the robotic crawler and/or control unit, enabling dynamic adjustments during operation of the robotic crawler within the gap of the machine. In some embodiments, visual inspection module <NUM> may include light sources <NUM>, <NUM>, <NUM>, <NUM>, <NUM> to improve visibility with cameras <NUM>, <NUM>, <NUM>. For example, light sources <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be LED lights with diffusers recessed into module housing <NUM>. In some embodiments, alternate inspection sensors may be used, including cameras with sensors for ultraviolet or infrared spectrums or other imaging technologies. Visual inspection module <NUM> includes a sensor interface <NUM> opposite mounting interface <NUM>. sensor interface <NUM> provides a mounting surface and/or power or signal interfaces for receiving the mounting interface of another sensor module to enable chaining of sensor modules. Sensor interface <NUM> includes a mounting surface <NUM>, fastener receptacle <NUM>, and connectors <NUM>, <NUM> for establishing a power, signal, and/or communication path between visual inspection module <NUM> and a sensor module attached to sensor interface <NUM>.

Referring to <FIG>, example sensor modules are shown for removable attachment to sensor interfaces on a robotic crawler. These sensor modules are shown as examples of different types of sensor or test modules that may be created or adapted for use on a modular robotic crawler.

Wedge tightness assessment module <NUM> may be an example of a mechanical test module. Wedge tightness assessment module <NUM> may include a mechanical test assembly <NUM> that may be deployed by the robotic crawler at a desired crawler positioning based on control signals from the robotic crawler or control unit. Mechanical test assembly <NUM> may provide test data back to the robotic crawler or control unit. Mechanical test assembly <NUM> may be connected to a module housing <NUM> defining a mounting interface <NUM> and accommodating fasteners <NUM>, <NUM> for removably attaching wedge tightness assessment module <NUM> to a robotic crawler. Mounting interface <NUM> is configured for removable attachment to a sensor interface on a robotic crawler, such as a sensor interface on a module mounting frame or a previously installed module, including a traction module with a sensor interface. In some embodiments, module housing <NUM> may include electronics, power source, communication channels, and/or test components to support and/or interface with mechanical test assembly <NUM>. In some embodiments, mounting interface <NUM> may include a connector for power and/or communication channels for control and/or data signals to and from wedge tightness assessment module <NUM>. In some embodiments, wedge tightness assessment module <NUM> may include visual sensors, light sources, or other subsystems to assist in conducting the relevant test protocol. In the embodiments shown, wedge tightness assessment module <NUM> may be a terminal sensor module because it does not include a sensor interface for receiving another sensor module.

Electromagnetic core imperfection detector module <NUM> may be an example of an electrical test module. Electromagnetic core imperfection detector module <NUM> may include an electrical test assembly <NUM> that may be activated by the robotic crawler at a desired crawler positioning based on control signals from the robotic crawler or control unit. Electrical test assembly <NUM> may provide test data back to the robotic crawler or control unit. Electrical test assembly <NUM> may be connected to or embedded in a module housing <NUM> defining a mounting interface <NUM> and accommodating fasteners <NUM>, <NUM> for removably attaching wedge tightness assessment module <NUM> to a robotic crawler. Mounting interface <NUM> is configured for removable attachment to a sensor interface on a robotic crawler, such as a sensor interface on a module mounting frame or a previously installed module, including a traction module with a sensor interface. In some embodiments, module housing <NUM> may include electronics, power source, communication channels, and/or test components to support and/or interface with electrical test assembly <NUM>. In some embodiments, mounting interface <NUM> may include a connector for power and/or communication channels for control and/or data signals to and from electromagnetic core imperfection detector module <NUM>. In some embodiments, electromagnetic core imperfection detector module <NUM> may include visual sensors, light sources, or other subsystems to assist in conducting the relevant test protocol. In some embodiments, electromagnetic core imperfection detector module <NUM> may include a sensor interface <NUM> opposite mounting interface <NUM>. Sensor interface <NUM> provides a mounting surface and/or power or signal interfaces for receiving the mounting interface of another sensor module to enable chaining of sensor modules. In some embodiments, sensor interface <NUM> includes a mounting surface <NUM>, fastener receptacle <NUM>, and connectors <NUM>, <NUM> for establishing a power, signal, and/or communication path between visual inspection module <NUM> and a sensor module attached to sensor interface <NUM>.

Referring to <FIG>, another configuration of a visual inspection sensor is shown as end region inspection module <NUM>, according to various embodiments. End region inspection module <NUM> may be configured to extend into a region of a machine that a robotic crawler may not otherwise be able to reach and enable visual inspection of that region, such as an obstructed end region accessible through an inspection gap that is too narrow for the robotic crawler and/or inaccessible to the traction modules (or any other form of locomotion) of the robotic crawler. End region inspection module <NUM> may include a module housing <NUM> defining a mounting interface <NUM> and accommodating fasteners <NUM>, <NUM> for removably attaching end region inspection module <NUM> to a robotic crawler. For example, mounting interface <NUM> may be configured for removable attachment to a sensor interface on a robotic crawler, such as a sensor interface on a module mounting frame or a previously installed module, including a traction module with a sensor interface. In some embodiments, module housing <NUM> may include electronics, power source, communication channels, and/or test components to support and/or interface with other test components of end region inspection module <NUM>. In some embodiments, mounting interface <NUM> may include a connectors <NUM>, <NUM> for power and/or communication channels for control and/or data signals to and from end region inspection module <NUM>. In some embodiments, end region inspection module <NUM> may include a fixed camera <NUM> and light sources <NUM>, <NUM>, <NUM> mounted on or in module housing <NUM>. In some embodiments, end region inspection module <NUM> includes an extension member <NUM> connected to module housing <NUM>. For example, extension member <NUM> may have a fixed mount <NUM> to module housing <NUM> and comprise a telescoping member with a fixed portion <NUM>, a telescoping portion <NUM>, and a slidably positionable joint <NUM> between fixed portion <NUM> and telescoping portion <NUM>. In some embodiments, the telescoping member may include an actuator in communication with the robotic crawler or the control unit to adjust the length of the telescoping member during operation of the robotic crawler within the gap. In some embodiments, extension member <NUM> further comprises one or more slidable supports that assist with positioning extension member <NUM>. For example, extension member <NUM> may include slidable magnetic pads <NUM>, <NUM>, <NUM>, <NUM> in laterally spaced pairs supported by brackets <NUM>, <NUM>. Slidable magnetic pads <NUM>, <NUM>, <NUM>, <NUM> may combine a magnetic core configured to provide an attachment force to one or more magnetic surfaces of the machine with a non-stick pad surface configured to move along the magnetic surface. Slidable magnetic pads <NUM>, <NUM>, <NUM>, <NUM> may be slidable on and detachable from the surface of the machine under the motive force of the robotic crawler, the telescoping member, or another positioning element. Slidable magnetic pads <NUM>, <NUM>, <NUM>, <NUM> may be spaced laterally from extension member <NUM> and their pad surfaces may define a plane for engaging with the surface of the machine. In one embodiment, one pair of slidable magnetic pads <NUM>, <NUM> may be attached to telescoping portion <NUM> and the other pair of slidable magnetic pads <NUM>, <NUM> may be attached to fixed portion <NUM>. Note that while the example is shown with a configuration of four pads, other configurations with any number of pads may also be feasible. Extension member <NUM> may connect to and support a rotatable camera assembly <NUM> at the distal end of extension member <NUM>. In some embodiments, rotating camera assembly <NUM> may include a rotating housing <NUM> with a camera <NUM>, such as a digital video camera, and a light source <NUM>, such as an LED with diffuser. In some embodiments, rotating camera assembly <NUM> may further include an electronics module <NUM> and a motor module <NUM>. For example, electronics module <NUM> may include electronics for processing visual data collected by camera <NUM> and communicating that visual data to the robotic crawler or control unit, such as by wired or wireless video streaming, and motor module <NUM> may provide a motor, position index, and control interface for controllably moving rotating housing <NUM>, camera <NUM>, and light source <NUM> during an inspection protocol.

Referring to <FIG>, a mechanical positioning module <NUM> is shown according to various embodiments. Mechanical positioning module <NUM> may be used to position a sensor module within the gap and relative to a crawler position of a robotic crawler. For example, mechanical positioning module may include one or more positionable joints to move a sensor interface (and an attached sensor module) to a desired height between the machine surfaces that define the gap. Mechanical positioning module <NUM> is shown in a gap <NUM> between a first surface <NUM> and a second surface <NUM> and attached to a robotic crawler <NUM> positioning a sensor interface housing <NUM> to clear a lip <NUM>. In some embodiments, mechanical positioning module <NUM> includes a mounting interface housing <NUM> that connects to a sensor interface of robotic crawler <NUM>, a mechanical positioning assembly <NUM> connected to mounting interface housing <NUM> at one end, and sensor interface housing <NUM> connected to the other end of mechanical positioning assembly <NUM>. For example, mounting interface housing <NUM> may include a mounting interface similar to those described above for sensor modules and compatible with one or more sensor interfaces on robotic crawler <NUM>. Mounting interface housing <NUM> may include a motor and other components for receiving control signals and controlling the position of mechanical positioning assembly <NUM>. Mechanical positioning assembly <NUM> may include a variety of positionable joints, members, and actuators for performing the desired positioning operations, such as a parallel lift capable of raising and lowering sensor interface housing <NUM> while maintaining it on plane parallel to the base of robotic crawler <NUM>. Sensor interface housing <NUM> may provide a sensor interface similar to those described above for receiving, positioning, and connecting a sensor module. In some embodiments, sensor interface housing <NUM> may be replaced with a sensor housing for an integrated sensor module with a positioning assembly.

Referring to <FIG>, a stacked configuration <NUM> of sensor modules <NUM>, <NUM>, <NUM> is shown according to various embodiments. For example, sensor module <NUM> may be an electrical test module similar to electromagnetic core imperfection detector module <NUM> in <FIG>. Sensor module <NUM> may be a visual inspection module similar to visual inspection module <NUM> in <FIG>. Sensor module <NUM> may be a mechanical test module similar to wedge tightness assessment module <NUM> in <FIG>. Sensor modules <NUM>, <NUM>, <NUM> may be connected to a crawler sensor interface <NUM> supported by a traction module <NUM>, providing electrical, mechanical, and communication connections to the robotic crawler. Sensor modules <NUM>, <NUM>, <NUM> may each be activated and controlled by the robotic crawler independently at desired crawler positions based on control signals from the robotic crawler or control unit. Any number of sensor modules <NUM>, <NUM>, <NUM> may be stacked and controlled in this fashion to the limits of the mechanical strength of modules and interfaces, as well as robotic crawler balance and the limits of whatever power and communication paths the interface architecture supports. Sensor modules <NUM>, <NUM>, <NUM> may each provide data back to the robotic crawler or control unit independently. Each of sensor modules <NUM>, <NUM>, <NUM> may be connected to or embedded in module housings <NUM>, <NUM>, <NUM> defining mounting interfaces <NUM>, <NUM>, <NUM> for removably attaching to the preceding sensor module or crawler sensor interface <NUM>. In some embodiments, mounting interfaces <NUM>, <NUM>, <NUM> may provide robust mechanical interfaces to adjacent sensor interfaces, such that <NUM>-<NUM> sensor modules may be stacked. In some embodiments, module housings <NUM>, <NUM>, <NUM> may include electronics, power sources or channels, communication channels, and/or test components to support and/or interface with their respective sensors. In some embodiments, mounting interfaces <NUM>, <NUM>, <NUM> may include connectors for power and/or communication channels for control and/or data signals to and from sensor modules <NUM>, <NUM>, <NUM>. Sensor modules <NUM>, <NUM> may include sensor interfaces <NUM>, <NUM> opposite mounting interfaces <NUM>, <NUM>. For example, each mated pair of crawler sensor interface <NUM> and sensor interfaces <NUM>, <NUM> with mounting interfaces <NUM>, <NUM>, <NUM> may include built in pins on one side and mating receptacles on the other side to establish operative electrical and/or signal contact between adjacent sensor modules <NUM>, <NUM>, <NUM>. Interconnected sensor modules <NUM>, <NUM>, <NUM> may provide one or more continuous channels through their respective module housings <NUM>, <NUM>, <NUM> to enable power and signals to pass through. In some embodiments, these continuous channels may include parallel channels enabling separate pathways to each of sensor modules <NUM>, <NUM>, <NUM> and in some embodiments serial and/or multiplexed channels may be used. Sensor module <NUM> may be a terminal sensor module that does not include a sensor interface and may only be used at the distal end of stacked configuration <NUM>. In stacked configuration <NUM>, sensor module <NUM> may be connected to crawler sensor interface <NUM> by mounting interface <NUM> and to sensor module <NUM> by sensor interface <NUM>. Sensor module <NUM> may be connected to sensor module <NUM> by mounting interface <NUM> and to sensor module <NUM> by sensor interface <NUM>. Sensor module <NUM> may be connected to sensor module <NUM> by mounting interface <NUM> and may terminate the stack or chain of sensor modules <NUM>, <NUM>, <NUM> extending from crawler sensor interface <NUM>. In some embodiments, sensor modules <NUM>, <NUM>, <NUM> may be operated simultaneously to perform simultaneous inspections or tests independently or based on relationships between sensor modules <NUM>, <NUM>, <NUM>, the robotic crawler, and or other sensor modules mounted elsewhere on the robotic crawler.

Claim 1:
A system (<NUM>) comprising:
a robotic crawler (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) having a plurality of multidirectional traction modules (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), an expandable body (<NUM>, <NUM>, <NUM>) connected to the multidirectional traction modules (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), and a plurality of sensor modules (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) positioned by the plurality of multidirectional traction modules (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>);
a control system (<NUM>) in communication with the robotic crawler (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), the control system (<NUM>) providing a control signal to the robotic crawler (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to navigate an inspection path within an annular gap (<NUM>, <NUM>) of a machine (<NUM>, <NUM>), wherein navigating the inspection path includes axial movement and radial movement of the plurality of multidirectional traction modules (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to inspect the annular gap (<NUM>, <NUM>) using the plurality of sensor modules (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>); characterized in that
each of the plurality of sensor modules includes a mounting interface, each mounting interface configured to attach to a sensor interface on the robotic crawler or one of the plurality of sensor modules.