Patent Description:
<CIT> discloses a moving device for moving on a tube sheet surface by inserting a leg driven by an actuator into a tube hole of a tube sheet of an end-tube heat exchanger, wherein the leg and the tube hole are engaged with each other. <CIT> discloses a water-chamber working apparatus with a base that holds heat transfer tubes on a tube plate surface and is fixed to the tube plate surface, and a manipulator coupled with the base and is suspended in a water chamber. The base includes a base body that is coupled with a manipulator, a wing capable of being displaced forward and backward with respect to the base body, and clamper that are arranged on the wing and are inserted into the heat transfer tube to clamp and hold the heat transfer tube. <CIT> discloses a serpentine robotic crawler having multiple dexterous manipulators supported about multiple frame units connected via an articulating linkage at proximal ends. The articulating linkage is capable of positioning the frames into various configurations. Dexterous manipulators are coupled to distal ends of the frame units and are positionable into various positions about the frame ends.

<CIT> discloses a system according to the preamble of claim <NUM>.

The following summary is provided to facilitate an understanding of some of the innovative features unique to the aspects disclosed herein, and is not intended to be a full description. A full appreciation of the various aspects can be gained by taking the entire specification, claims, and abstract as a whole. The invention is defined by a system according to claim <NUM>.

In various aspects, a system configured to service a heat exchanger including a plurality of tubes extending through a tubesheet is disclosed. The system includes a manipulator including a first end effector configured to accommodate an instrument configured to service the heat exchanger, wherein the first end effector includes a first actuator coupled to a first gripper, wherein the first actuator is configured to extend the first gripper into a tube of the plurality of tubes, and wherein the first gripper is configured to secure the manipulator to the tubesheet, a second end effector including a second actuator coupled to a second gripper, wherein the second actuator is configured to extend into a tube of the plurality of tubes, and wherein the second gripper is configured to secure the manipulator to the tubesheet, and an articulation assembly including a first link, a second link, and three joint axis motors, wherein the first link is pivotally connected to the first end effector and rotatable about a first axis, wherein the first link is pivotally connected to the second link and rotatable about a second axis, and wherein the second link is pivotally connected to the second end effector and rotatable about a third axis. The system further includes a control circuit coupled to the first end effector, the second end effector, and the articulation assembly, wherein control circuit is configured to command the motor to move the first end effector relative to the second end effector in a plane that is parallel to the tubesheet, based on an instruction.

In various aspects, a manipulator configured to navigate a heat exchanger including a plurality of tubes extending through a tubesheet is disclosed. The manipulator includes a first end effector configured to accommodate an instrument configured to service the heat exchanger, wherein the first end effector includes a first actuator coupled to a first gripper, wherein the first actuator is configured to extend the first gripper into a tube of the plurality of tubes, and wherein the first gripper is configured to secure the manipulator to the tubesheet. The manipulator also includes a second end effector including a second actuator coupled to a second gripper, wherein the second actuator is configured to extend into a tube of the plurality of tubes, and wherein the second gripper is configured to secure the manipulator to the tubesheet. The manipulator also includes an articulation assembly including a first link and a second link, wherein the first link is pivotally connected to the first end effector and rotatable about a first axis, wherein the first link is pivotally connected to the second link and rotatable about a second axis, and wherein the second link is pivotally connected to the second end effector and rotatable about a third axis. When the second gripper is securing the manipulator to the tubesheet, the articulation assembly is configured to enable the first end effector to move relative to the second end effector in a plane that is parallel to the tubesheet. In various aspects, a method of servicing a heat exchanger including a plurality of tubes extending through a tubesheet is disclosed. The method employs a manipulator including a first end effector configured to accommodate an instrument configured to service the heat exchanger, wherein the first end effector includes a first actuator configured to extend a first gripper into a tube of the plurality of tubes, a second end effector configured to accommodate an instrument configured to service the heat exchanger, wherein the second end effector includes a second actuator configured to extend a second gripper into a tube of the plurality of tubes, and an articulation assembly including a first link, a second link, and a motor configured to move the first end effector relative to the second end effector in a plane that is parallel to the tubesheet, wherein the first gripper and second gripper are configured to secure the manipulator to the tubesheet. The method includes extending the second gripper into a tube of the plurality of tubes, securing, by the second gripper, the manipulator to the tubesheet, moving, by the motors, the first end effector relative to the second end effector in a plane that is parallel to the tubesheet, until the first end effector arrives at a first desired location; and servicing, by the first instrument, the heat exchanger at the first desired location.

Various features of the aspects described herein are set forth with particularity in the appended claims. The various aspects, however, both as to organization and methods of operation, together with advantages thereof, may be understood in accordance with the following description taken in conjunction with the accompanying drawings as follows:.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate various aspects of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

Numerous specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture, and use of the aspects as described in the disclosure and illustrated in the accompanying drawings. Well-known operations, components, and elements have not been described in detail so as not to obscure the aspects described in the specification. The reader will understand that the aspects described and illustrated herein are non-limiting examples, and thus it can be appreciated that the specific structural and functional details disclosed herein may be representative and illustrative. Variations and changes thereto may be made without departing from the scope of the claims. Furthermore, it is to be understood that such terms as "forward", "rearward", "left", "right", "upwardly", "downwardly", and the like are words of convenience and are not to be construed as limiting terms. Furthermore, it is to be understood that such terms as "forward", "rearward", "left", "right", "upwardly", "downwardly", and the like are words of convenience and are not to be construed as limiting terms.

In the following description, like reference characters designate like or corresponding parts throughout the several views of the drawings.

Before explaining various aspects of the articulated manipulator in detail, it should be noted that the illustrative examples are not limited in application or use to the details of construction and arrangement of parts illustrated in the accompanying drawings and description. The illustrative examples may be implemented or incorporated in other aspects, variations, and modifications, and may be practiced or carried out in various ways. Further, unless otherwise indicated, the terms and expressions employed herein have been chosen for the purpose of describing the illustrative examples for the convenience of the reader and are not for the purpose of limitation thereof. Also, it will be appreciated that one or more of the following-described aspects, expressions of aspects, and/or examples, can be combined with any one or more of the other following-described aspects, expressions of aspects, and/or examples.

The present disclosure is directed to an articulated manipulator configured to navigate and service any heat exchanger with a planar tubesheet. Many mechanical systems, such as nuclear electrical power generators, rely on the effective dissipation of heat. For example, in a pressurized water reactor, the heat generated by the nuclear reaction may be absorbed by a primary coolant that circulates through the reactor core and is utilized to generate steam in a steam generator. The steam generator can be configured as an upright cylindrical pressure vessel with hemispherical end sections. A traverse plate called a tubesheet, located at the lower end of the cylindrical section, can divide the steam generator into a primary side, or lower hemispherical section below the tubesheet, and a secondary side, a corresponding section positioned above the tubesheet. A vertical wall may bisect the primary side into an inlet section and an outlet section. The tubesheet can include a thick carbon steel plate with an array of thousands of holes into which are inserted the ends of U-shaped tubes. A first end of each U-shaped tube can be inserted into a hole within the primary side of the tubesheet that communicates with an inlet section. A second end of the U-shaped tube can be inserted into a hole within the tubesheet that communicates with an outlet section. Accordingly, a coolant can be pressurized and introduced into the inlet section, circulate through the U-shaped tubes, and exit through the outlet section. Additionally, water can be introduced into similar configuration of the secondary side of the steam generator, circulate around the U-shaped tubes, turning into steam by heat given up by the primary coolant. Although the present disclosure describes aspects in which an articulated manipulator can be used to service a heat exchanger within a nuclear power electrical generation plant, such aspects are merely exemplary. Thus, it will be appreciated that the articulated manipulator can be implemented to navigate and service any heat exchanger with a planar tubesheet.

In time, degradation can occur within the material of U-shaped tubes. This is undesirable because the primary coolant is radioactive and any leakage of the coolant into the secondary side of the generator can contaminates the steam. Because of the radiation hazard present in nuclear powered steam generators, it is preferable to remotely inspect and/or service the U-shaped tubes to minimize the risk of detrimental exposure of personnel. Consequently, a number of robotic systems have been developed to inspect and/or service such configurations of heat exchanger tubes. Such robotic systems can include a motorized transport sub-system configured to position an "end effector" of the robot in a desired location of mechanical system, such as the heat exchanger. The end effector can be outfitted with a variety specialized tools designed to service the mechanical system, thereby mitigating the aforementioned risk of exposure of personnel.

One such robot is disclosed in <CIT>. Another robotic arm configured service heat exchangers is the ROSA (Remotely Operated Service Arm) developed by Westinghouse Electric Corporation located in Pittsburgh, Pa. However, as heat exchanger technology evolves, the versatility and efficiency of known robots can be improved. Tube sizes are decreasing and a variety of heat exchanger designs and thus, tubesheet configurations have been developed and implemented for specific applications. For example, square and triangular pitch tubesheet configurations are commonly used creating difficulty for known robots to be universally implemented across a variety of systems. Manufacturing defects can also preclude known robots from servicing the tubesheet, thereby necessitating manual repositioning and increasing the risk of human exposure to potentially hazardous radiation. Additionally, given the complex and extensive network of tubes involved in such heat exchangers, time can be of the essence to optimize the service of such systems. As such, there is a need for a manipulator with improved articulation and geometric versatility. Such a manipulator should be include an articulation system capable of traversing heat exchangers of varying configurations, avoiding the inevitable manufacturing defects without human intervention, and efficiently servicing a tubesheet due to its improved range of motion.

Referring now to <FIG>, an isometric view of an articulated manipulator <NUM> is illustrated in accordance with at least one non-limiting aspect of the present disclosure. As will be described, the manipulator <NUM> is particularly configured to efficiently navigate and service any heat exchanger with a planar tubesheet. For example, the manipulator <NUM> of <FIG> can be employed to service a heat exchanger of a nuclear power generation system, and more specifically, a tubesheet of the heat exchanger comprising a plurality of tubes. As used herein, the term "service" shall be broadly interpreted to describe a variety of procedures associated with the nuclear power generation. For example, the manipulator <NUM> can be specifically configured to inspect the tubesheet using a wide variety of non-destructive testing methods, including but not limited to Eddy Current Testing. Additionally and/or alternatively, the manipulator <NUM> can be specifically configured to perform any number of maintenance operations on the tubesheet of the heat exchanger. Although the aspects described herein are specifically directed to manipulators <NUM> configured to service the tubes terminating in the tubesheets of heat exchangers, it shall be understood that, in other non-limiting aspects, the manipulator <NUM> can be similarly deployed in various other systems that utilize heat exchangers with planar tubesheets, not to be limited to nuclear power generation plants.

According to the non-limiting aspect of <FIG>, the manipulator <NUM> can include a first end effector <NUM> and a second end effector <NUM>. A first pair of actuators <NUM> and a first pair of guide tubes <NUM> can be coupled to the first end effector <NUM>, and a second pair of actuators <NUM> and a second pair of guide tubes <NUM> can be coupled to the second end effector <NUM>. The guide tubes <NUM>, <NUM> can be configured to accommodate an instrument configured to service the heat exchanger. However, in other non-limiting aspects, the end effectors <NUM>, <NUM> can be configured to accommodate an instrument configured to service the heat exchanger without the guide tubes <NUM>, <NUM>. For example, instruments can be directly attached to the end effectors <NUM>, <NUM> through mechanical coupling. Alternatively, the end effectors <NUM>, <NUM> can include modular connectors to interchangeably accommodate a wide variety of instruments. Alternatively and/or additionally, the manipulator <NUM> can be modularly configured such that the end effectors <NUM>, <NUM> themselves can be interchangeably removed and attached in accordance with the intended application and/or user preference. The end effectors <NUM>, <NUM> can include different grippers, instruments, and/or instrumentation configurations, and can be swapped out to accomplish a wide variety of tasks.

The manipulator <NUM> if <FIG> also includes an articulation system <NUM> comprising a first link <NUM> and a second link <NUM> pivotally connected to the first end effector <NUM> and second end effector <NUM>, respectively. Although the non-limiting aspect of <FIG> depicts an articulated manipulator <NUM> with two end effectors, <NUM>, <NUM>, each having a pair of actuators <NUM>, <NUM> and a pair of guide tubes <NUM>, <NUM>, in other non-limiting aspects, the manipulator includes any number of end effectors configured with any number of actuators and/or guide tubes, as is necessary for the specific implementation of the device.

In further reference of <FIG>, the first end effector <NUM> and second end effector <NUM> each have a pair of actuators <NUM>, <NUM> configured to extend and retract relative to the end effector itself. In some aspects, one or more actuator can be outfitted with a gripper configured to secure the manipulator <NUM> to the tubesheet. For example, in the non-limiting aspect of <FIG>, each of the first actuators <NUM> and the second actuators <NUM> has a gripper <NUM> configured to be inserted into a hole of the tubesheet. As will be described in further detail, each of the grippers <NUM> can be subsequently moved along a lateral axis L (<FIG>) that runs perpendicular to the axis of extension and/or retraction until at least one of the grippers <NUM> comes into contact with an inner wall of the hole. In the non-limiting aspect of <FIG>, each of the first pair of actuators <NUM> and each of the second pair of actuators <NUM> can include a gripper <NUM> that can move laterally after being extended and inserted into a hole of the tubesheet. For example, each of the grippers <NUM> of an end effector <NUM>, <NUM> may move towards one another until they contact and apply an inward pressure on an inner wall of their respective hole. Alternatively and/or additionally, the grippers <NUM> of each end effector <NUM>, <NUM> may move laterally away from one another, until they contact and apply an outward pressure on an inner wall of their respective hole. Accordingly, through the use of an applied pressure and/or friction between the gripper <NUM> and inner wall, at least one of the end effectors <NUM>, <NUM> of the manipulator <NUM> can be anchored to the tubesheet. The present disclosure contemplates multiple aspects with varying configurations of actuators <NUM>, <NUM> and grippers <NUM> to grip the tubesheet in a specific way, depending on the particular needs of the application and/or preferences of the user.

Still referring to <FIG>, the manipulator <NUM> can be configured such that the first end effector <NUM> moves into place via the articulation system <NUM> once the second end effector <NUM> is anchored to the tubesheet. For example, the articulation system <NUM> of <FIG> includes a first link <NUM> pivotally connected to the first end effector <NUM> and a second link <NUM>, which is in turn pivotally connected to the second end effector <NUM>. Accordingly, the first link <NUM> can rotate relative to the first end effector <NUM> about a first axis A1, the first link <NUM> and second link <NUM> can rotate relative to the other about a second axis A2, and the second link <NUM> can rotate relative to the second end effector <NUM> about a third axis A3. Accordingly, the articulation assembly <NUM> can enable the first end effector <NUM> and/or second end effector <NUM> to move between a wide array of coordinates within a desired plane, depending on which end effector is anchored to the tubesheet.

For example, the articulation assembly <NUM> of <FIG> can enable the first end effector <NUM> to rotate about the first axis A1 and the first link <NUM> to rotate about the second axis A2 when the second pair of actuators <NUM> of the second end effector <NUM> is gripping the tubesheet, such that the manipulator <NUM> can move anywhere within a plane P1 defined by the X and Y axes. In the non-limiting aspect of <FIG>, the plane P1 is parallel to the tubesheet, and the first end effector <NUM> and/or second end effector <NUM> can be repositioned to any desired X, Y coordinate within the plane P1. Although the articulation assembly <NUM> includes a first link <NUM> and a second link <NUM> and three axes A1, A2, A3, in other non-limiting aspects contemplated by the present disclosure, the articulation assembly <NUM> of manipulator <NUM> can include any number of links and axes to specifically tailored for a variety of applications and/or user preferences. The articulation assembly <NUM> of the manipulator <NUM> can provide an improved range of motion over existing manipulators with fewer axes of motion. Additionally and/or alternatively, the articulation assembly <NUM> can allow the manipulator <NUM> of <FIG> to traverse between coordinates using fewer motions, thereby promoting efficiency. Accordingly, the manipulator <NUM> of <FIG> is more effective and can perform a wider array of tubesheet services, including inspection and/or maintenance procedures.

The manipulator <NUM> can be configured to engage with at least one instrument depending on the intended application and/or user preference. For example, in the non-limiting aspect of <FIG>, the manipulator <NUM> can include a first pair of guide tubes <NUM> installed within a guide block of the first end effector <NUM> and a second pair of guide tubes <NUM> installed within a guide block of the second end effector <NUM>. The guide tubes <NUM>, <NUM> can include hollow tubes extending through the end effectors <NUM>, <NUM>. In some non-limiting aspects, the guide tubes can include additional components, such as flexible conduits and/or fittings to ensure a proper engagement with and positioning of an inserted instrument. Accordingly, the guide tubes <NUM>, <NUM> of <FIG> can be configured to accommodate and guide externally inserted probes, or any other instrument suitable for the intended application, to ensure proper placement for inspection and/or servicing of the heat exchanger. However, the in other non-limiting aspects, any instrument suitable for the intended application can be mechanically coupled to the end effectors <NUM>, <NUM>. In such aspects, the mechanical connection can be modular such that a multitude of interchangeable instruments can be mechanically coupled to the manipulator <NUM>, according to user preference. In still other non-limiting aspects, the guide tubes <NUM>, <NUM> of manipulator <NUM> can include actuators configured to extend and/or retract instruments without external influence.

The manipulator <NUM> and, more specifically, the guide tubes <NUM>, <NUM> of <FIG> are configured to accommodate probes configured for non-destructive testing of a tubesheet of a heat exchanger, such as Eddy-current testing. Accordingly, the manipulator <NUM> can inspect a heat exchanger by articulating to a desired position such that probes can be inserted into the guide tubes <NUM>, <NUM>. The probes can then induce an electromagnetic field, which can be used to detect and characterize surface and sub-surface flaws present throughout a conductive material of the tubesheet and more generally, the heat exchanger itself. Thus, the manipulator <NUM> of <FIG> can be used to improve compliance to regulations for nuclear power electrical generation plants, which require frequent eddy-current testing. However, Eddy-current testing is only one example of the testing contemplated by the present disclosure. In other non-limiting aspects, the guide tubes <NUM>, <NUM> can accommodate instruments configured for any means of testing, inspection, and/or service.

For example, in some non-limiting aspects, the manipulator <NUM> can include a plugging tool, a welder, saw, and/or any other instrument configured to interact with or service the heat exchanger on one or more of the end effectors <NUM>, <NUM>. In some non-limiting aspects, the tools can be remotely operated. In other non-limiting aspects, the manipulator <NUM> can include any combination of instruments. For example, the first pair of guide tubes <NUM> can be configured to accommodate a pair of guide tubes <NUM> configured to inspect the tubesheet , and the second pair of guide tubes <NUM> can be configured to accommodate an instrument configured to service the heat exchanger. Additionally and/or alternatively, the guide tubes <NUM>, <NUM> of the manipulator <NUM> can be modular and capable of accommodating any number of interchangeable instruments. The varying configurations contemplated by the present disclosure further enhance the productivity of the manipulator <NUM> and reduce the need for separate manipulators <NUM> to perform different tasks on the same tubesheet.

Because the manipulator <NUM> can include guide tubes <NUM>, <NUM> on each of its end effectors <NUM>, <NUM>, the manipulator <NUM> of <FIG> can more efficiently service the heat exchanger. This further reduces the number of motions required by known manipulators, thereby enhancing the productivity of the manipulator <NUM>. In the non-limiting aspect of <FIG>, the manipulator <NUM> can be configured to position the guide tubes <NUM>, <NUM> and/or other instruments relative to the tubesheet, once the manipulator <NUM> has been properly positioned and secured. For example, in the non-limiting aspect of <FIG>, a user can insert an external probe into the guide tubes <NUM>, <NUM>, which are configured to engage with and guide the probe to a proper position on the tubesheet to inspect the heat exchanger. However, in other non-limiting aspects, the guide tubes <NUM>, <NUM> can include actuators to facilitate the extension and retraction of an instrument relative to the heat exchanger. In still other non-limiting aspects, instruments can be mechanically coupled to the end effectors <NUM>, <NUM> and the manipulator <NUM> itself can be configured to move towards and away from the heat exchanger. Regardless, the manipulator <NUM> can be appropriately configured to properly orient a wide variety of instruments relative to the heat exchanger for the required inspection and/or service.

Referring now to <FIG>, a plan view of the articulated manipulator <NUM> of <FIG> is illustrated as seen from the tubesheet of a heat exchanger. Notably, the axes A1, A2, A3 of the articulation assembly <NUM> highlight the full range of motion afforded to the manipulator <NUM>. It will be appreciated that the manipulator can position the first end effector <NUM> and second end effector <NUM> in a wide array of positions relative to one another. Therefore, if the second end effector <NUM> is secured to the tubesheet, the first end effector <NUM> can service tubes within a specifically configured radius defined by a length L1 of the first articulation link <NUM> and a length L2 of the second articulation link <NUM>. Thus, the articulation assembly <NUM> can be configured to reduce the number of maneuvers the manipulator <NUM> is required to perform in order to service the entire tubesheet. Additionally and/or alternatively, the geometry of the first end effector <NUM> and second end effector <NUM> can be further configured to promote efficiency, depending on the intended application and/or preference of the user.

In further reference to <FIG>, the lateral axis L is illustrated. According to the non-limiting aspect of <FIG> and <FIG>, the grippers <NUM> can be configured for lateral movement along the L-axis in order to apply the required pressure to an inner wall of a tube of the tubesheet to secure the manipulator <NUM> in place. However, in other non-limiting aspects, the grippers can be configured to move in any particular direction. In still other non-limiting aspects the grippers <NUM> can secure the manipulator <NUM> to the tubesheet in a variety of ways, including but not limited to magnetic, suction, and/or other forms of mechanical attachment, including combinations thereof. Thus, the grippers <NUM> can be configured to move as required to properly secure the manipulator <NUM> to the tubesheet, depending on the means of mechanical attachment.

Referring now to <FIG>, an elevation view of the articulated manipulator <NUM> of <FIG> and <FIG> is depicted in accordance with at least one non-limiting aspect of the present disclosure. In the elevation view of <FIG>, one of the grippers <NUM> of the second end effector <NUM> is depicted as extended by the one actuator <NUM> of the pair of actuators, presumably gripping a hole of the tubesheet. Specifically, the geometric orientation of the first end effector <NUM> relative to the first link <NUM>, the first link <NUM> relative to the second link <NUM>, and the second link <NUM> relative to the second end effector <NUM> can be intentionally configured depending on the intended use of the manipulator <NUM> and/or user preference. For example, according to the non-limiting aspect of <FIG>, the first end effector <NUM> can be configured as a multi-planar bracket, including a first surface <NUM> and a second surface <NUM> orthogonally connected to the first surface <NUM> by a central component <NUM>. The first pair of actuators <NUM> can be mounted on an underside of the first surface <NUM>, which can be further configured to include a block into which the guide tubes <NUM> and/or other instruments can be installed. The second surface <NUM> is pivotally connected to the first link <NUM> of the articulation assembly <NUM> via a first motor assembly <NUM>. The first link <NUM> can be pivotally connected to the second link <NUM> via a second motor assembly <NUM>.

In further reference to <FIG>, the second end effector <NUM> can be pivotally connected to the second link <NUM> via a third motor assembly <NUM>. According to the non-limiting aspect of <FIG>, the second end effector <NUM> can further include a first surface <NUM>. Similar to the first end effector <NUM>, the second pair of actuators <NUM> can be mounted on an underside of the first surface <NUM>, which can be further configured to include a guide tube <NUM> into which probes and/or other instruments can be installed. Accordingly, the first surface <NUM> of the first end effector <NUM> and the first surface <NUM> of the second end effector <NUM> can be configured to exist in the same plane P2, which is parallel to both the plane P1 in which the manipulator <NUM> is configured to move, and a planar face of the tubesheet. Accordingly, the manipulator <NUM> of <FIG> is specifically designed such that the starting point of the grippers <NUM> and/or guide tubes <NUM>, <NUM> is uniform for both the first end effector <NUM> and second end effector <NUM>. This can simplify the dynamics of the maneuvers the manipulator <NUM> must perform to efficiently service the heat exchanger, which can further reduce time and processing resources. Additionally, the geometric configuration depicted in <FIG> can assist the manipulator <NUM> in navigating various manufacturing defects of the tubesheet, such as burrs, lips, and uneven surfaces, without human intervention.

According to other non-limiting aspects of the present disclosure, the first end effector <NUM>, the second end effector <NUM>, the first link <NUM>, and the second link <NUM> can include any number of geometric orientations such that the guide tubes <NUM>, <NUM> and/or grippers <NUM> are configured to accommodate the intended application and/or preferences of the user. For example, in some non-limiting aspects, the second end effector <NUM> also includes a multi-planar bracket, and the grippers <NUM> of the first end effector <NUM> can be positioned in a different plane than the grippers <NUM> of the second end effector <NUM>. Thus, the manipulator <NUM> can accommodate tubesheets of different configurations, including coplanar tubesheets with discrete sections, and can seamlessly navigate discontinuities that occur between the sections without human intervention. In still other non-limiting aspects, the manipulator <NUM> can be modularly configured to accommodate end effectors of numerous geometric configurations, such that the same manipulator <NUM> can be modified and implemented across a wide variety of tubesheets and applications.

The articulation assembly <NUM> can be configured with a variety of mechanisms to improve the precision with which the manipulator <NUM> is moved. For example, the manipulator <NUM> of <FIG> includes a first motor <NUM> aligned with the first axis A1, a second motor <NUM> aligned with the second axis A2, and a third motor <NUM> aligned with the third axis A3. The first motor <NUM>, the second motor <NUM>, and the third motor <NUM> of articulation assembly <NUM> can be specifically selected and configured to enhance the maneuverability of the manipulator <NUM>. For example, the first motor <NUM>, second motor <NUM>, and third motor <NUM> can be stepper motors, geared servo motors, piezoelectric motors, or any combination thereof. Of course, the present disclosure contemplates other non-limiting aspects wherein the articulation assembly <NUM> includes any number of controllable, rotary, actuators tailored to its intended application.

Additionally, the manipulator <NUM> can include a processor configured to communicate with a control circuit. The processor can be configured to execute instructions stored in a memory either coupled to the manipulator <NUM>, or remotely located. In still other non-limiting aspects, the manipulator <NUM> can include a receiver and/or a transmitter configured to communicate with a remote source of instructions. Accordingly, the processor can command the articulation assembly <NUM> of the manipulator <NUM> to perform a series of maneuvers based on instructions stored in the memory. Alternatively and/or additionally, the processor can command the articulation assembly <NUM> of the manipulator <NUM> to perform a series of maneuvers based on instructions it receives in real-time from a user in a remote location. Thus, a user can either deploy the manipulator <NUM> for autonomous inspection and/or service of the tubesheet, or remotely command the manipulator <NUM> to inspect and/or service the heat exchanger. In other non-limiting aspects, the manipulator can be configured to autonomously perform a series of maneuver and a user can override the autonomous control as needed. Regardless, the manipulator <NUM> can be specifically configured to minimize the risk of human exposure to radiation.

Referring now to <FIG> and <FIG>, the articulation assembly <NUM> is further illustrated in more detail. For example, <FIG> illustrates a sectioned view of the manipulator <NUM> taken along line <NUM>-<NUM> of <FIG>. <FIG> illustrates a sectioned view of the manipulator <NUM> taken along line <NUM>-<NUM> of <FIG>. The first motor <NUM>, the second motor <NUM>, or the third motor <NUM> of the articulation assembly <NUM> can include any number of mechanisms to ensure the proper routing of wires and prevent entanglement while the manipulator <NUM> maneuvers about the tubesheet. For example, in some non-limiting aspects, a slip ring assembly can be positioned about the first axis A1, the second axis A2, or the third axis A3 of the manipulator <NUM> to suit the needs of the intended application and further enhance the maneuverability of the manipulator.

In further reference to <FIG> and <FIG>, the manipulator <NUM> can further include gearing assemblies to manage the rotation of the first end effector <NUM>, the second end effector <NUM>, the first articulation link <NUM>, and the second articulation link <NUM>, relative to one another. For example, various gears can be installed about the first axis A1, the second axis A2, and/or the third axis A3 to increase or decrease a speed of rotation, reverse the direction of rotation, and transmit rotational motion to a preferred axis. Additionally and/or alternatively, the manipulator <NUM> can include a transmission. Accordingly, the manipulator <NUM> can be specifically configured to manage the torque applied to the first end effector <NUM>, the second end effector <NUM>, the first articulation link <NUM>, and/or the second articulation link <NUM>, depending on its intended application or user preference.

Referring now to <FIG>, an elevation view of a gripper assembly <NUM> to secure the articulated manipulator <NUM> of <FIG> to a tubesheet of the heat exchanger of the nuclear power electrical generation plants is depicted in accordance with at least one aspect of the present disclosure. <FIG> illustrates a sectioned view taken along line <NUM>-<NUM> of <FIG>, in accordance with at least one non-limiting aspect of the present disclosure. Specifically, the gripper assembly <NUM> includes a camlock configuration. In the non-limiting aspect of <FIG>, standoff pins <NUM> are placed in contact with the tubesheet using the cylinder block <NUM>. Compressed air can be released from chamber <NUM> (<FIG>) through a fitting, permitting springs <NUM> to raise a cylinder <NUM> and place gripper fingers <NUM> (<FIG>) within a steam generator tube. Guide pin <NUM> maintains alignment of the cylinder <NUM> with the gripper. A limit switch <NUM>, which is actuated by the guide pin <NUM>, can be used to verify insertion.

In further reference to <FIG>, the guide pin <NUM> is protected within housing <NUM>. The limit switch has three functions: (<NUM>) To assure that the gripper is in the full up position prior to activation of the gripper fingers <NUM> to press out against the corresponding heat exchanger tubes; (<NUM>) To detect if the camlock does not fully grip the corresponding heat exchanger tube (the limit switch will indicate that the gripper is not fully up when the gripper is pulled downward after the gripper fingers are radially extenuated, to fully seat the robot standoff pins <NUM> against the tubesheet <NUM>); and (<NUM>) To detect if there is a missing tube, e.g., at the end of a row or column, or a plugged tube, because the gripper will not fully insert. This latter feature can be used to verify the position of the robot as it moves across the tubesheet and is a significant feature of this invention. With the gripper fingers <NUM> inserted in the tube, actuator piston <NUM> is forced upward with compressed air supplied through fitting <NUM>. As the actuator piston travels upward, balls <NUM> roll on tapered raceways <NUM> bringing gripper fingers in tight contact with the tube. Balls are used to reduce friction between the gripper fingers and the actuator piston enabling a high contact force, e.g., approximately <NUM><NUM> N (<NUM>,<NUM> lbs. ), to be obtained with a relatively small pneumatic piston diameter. The low rolling friction of the balls eliminates the self-locking property of small angle tapers. The next operational sequence for the gripper is to pressurize chamber <NUM> which attempts to remove the gripper fingers from the tube. Since the gripper fingers are secured to the tube, the entire gripper is biased upward forcing pins <NUM> in close contact with the tubesheet. With the pins tightly against the tubesheet, the manipulator is forced to stay parallel and in close proximity to the tubesheet.

Still referring to <FIG>, the removal of the gripper from the tube can be performed as follows. Compressed air is expelled from chamber <NUM> relieving the force on the gripper fingers <NUM>. The actuator pin is lowered by introducing compressed air into fitting <NUM> while releasing air through fitting <NUM>. Nose cone <NUM> ensures the balls are returned to their original position and that gripper fingers <NUM> are captured. The actuator cylinder <NUM> is then lowered by pressurizing chamber <NUM>.

<FIG> illustrates a sectioned view taken along line <NUM>-<NUM> of <FIG>, in accordance with another non-limiting aspect of the present disclosure. Like reference characters refer to the corresponding elements previously described with respect to <FIG>. The difference in the aspect of <FIG> over that of <FIG> is that a spring <NUM> has been added around the top of the actuator piston <NUM> to bias the fingers <NUM> against the corresponding heat exchanger tube when the fingers are inserted within the tube to prevent an unintentional release. Additionally, the ball bearings <NUM> are retained within a sleeve, but travel as previously stated along the raceway when the piston <NUM> is actuated to force the fingers <NUM> radially outward.

<FIG> is an enlarged view of the gripping finger area of the gripper illustrated in <FIG>. It can be appreciated that the bearings <NUM> are retained within a sleeve <NUM> each supported within its own pocket and free to roll as the actuator piston moves up to force the fingers <NUM> radially outward. To retract the gripper fingers <NUM> air is introduced through the fitting <NUM> to force the piston in the opposite direction and the fingers <NUM> are forced inward, in turn forcing the ball bearings <NUM> within the sleeve <NUM> downward until they are seated at their lower extent of travel and the fingers <NUM> are captured by the nose cone <NUM>. The bearing balls <NUM> will be forced to the lowest position when the nose cone <NUM> is retracted. This assures the gripper fingers <NUM> will be fully collapsed when the actuator piston <NUM> and guide <NUM> are retracted. The guide <NUM>, actuator <NUM> and gripper fingers <NUM> are held rotationally fixed, with the small horizontal pin <NUM> in the center of the camlock to assure the balls <NUM> are retained in the raceways and do not move to the open slots between the gripper fingers <NUM>. In total, there are <NUM> balls circumferentially-spaced in six axially-extending rows positioned substantially equidistantly, circumferentially around the actuator piston <NUM>. However, in other non-limiting aspects, the specific number and configuration of rows and/or balls can vary, depending on the intended application.

Claim 1:
A system configured to service a heat exchanger, wherein the heat exchanger comprises a plurality of tubes extending through a tubesheet, the system comprising:
a manipulator (<NUM>) comprising:
a first end effector (<NUM>) comprising a first actuator (<NUM>) coupled to a first gripper (<NUM>) and configured to accommodate an instrument configured to service the heat exchanger, wherein the first actuator (<NUM>) is configured to extend the first gripper (<NUM>) into a tube of the plurality of tubes, and wherein the first gripper (<NUM>) is configured to secure the manipulator (<NUM>) to the tubesheet;
a second end effector (<NUM>) comprising a second actuator (<NUM>) coupled to a second gripper (<NUM>), wherein the second actuator (<NUM>) is configured to extend into a tube of the plurality of tubes, and wherein the second gripper (<NUM>) is configured to secure the manipulator (<NUM>) to the tubesheet; and
an articulation assembly (<NUM>) comprising a first link (<NUM>), a second link (<NUM>), and three motors (<NUM>; <NUM>; <NUM>); and
a control circuit coupled to the first end effector (<NUM>), the second end effector (<NUM>), and the articulation assembly (<NUM>), wherein control circuit is configured to cause the motors (<NUM>; <NUM>; <NUM>) to move the first end effector (<NUM>) relative to the second end effector (<NUM>) in a plane (P1) that is parallel to the tubesheet, based on an instruction;
characterized in that
the first link (<NUM>) is pivotally connected to the first end effector (<NUM>) and rotatable about a first axis (A1), the first link (<NUM>) is pivotally connected to the second link (<NUM>) and rotatable about a second axis (A2), and the second link (<NUM>) is pivotally connected to the second end effector (<NUM>) and rotatable about a third axis (A3).