Patent Publication Number: US-2017370173-A1

Title: Robotic manipulators for subsea, topside, and onshore operations

Description:
BACKGROUND 
     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the presently described embodiments. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present embodiments. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
     In order to meet consumer and industrial demand for natural resources, companies often invest significant amounts of time and money in finding and extracting oil, natural gas, and other subterranean resources from the earth. Particularly, once a desired subterranean resource such as oil or natural gas is discovered, drilling and production systems are often employed to access and extract the resource. These systems may be located onshore or offshore depending on the location of a desired resource. 
     Offshore systems can include topside devices positioned above the surface of the water, such as on a vessel or platform, and subsea devices positioned underwater, such as on the seabed. Whether located subsea, topside, or onshore, devices used in drilling and production systems can themselves include many components to be actuated, installed, or retrieved to facilitate drilling or production. In topside and onshore contexts, operators may manually perform such support operations. In subsea contexts, a working vessel can be positioned above a subsea installation and a remotely operated vehicle (ROV) can be launched to travel to the subsea installation to perform support operations for the subsea devices. 
     SUMMARY 
     Certain aspects of some embodiments disclosed herein are set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of certain forms the invention might take and that these aspects are not intended to limit the scope of the invention. Indeed, the invention may encompass a variety of aspects that may not be set forth below. 
     At least some embodiments of the present disclosure generally relate to robotic manipulators for facilitating support operations for an oilfield device. The robotic manipulators can include robotic arms with various degrees of freedom that allow the arms to perform a wide array of support functions. The robotic manipulators can be used with subsea, topside, and onshore devices, such as manifolds, trees, pumps, and blowout preventers. In some instances, a robotic manipulator includes a head adapted to receive any of multiple, interchangeable end effectors to increase the versatility of the robotic manipulator and enable a wider range of support operations. When not installed on the robotic manipulator, the multiple end effectors can be held in a tool box accessible to the robotic manipulator to enable efficient retooling of the robotic manipulator by simply switching end effectors. 
     Various refinements of the features noted above may exist in relation to various aspects of the present embodiments. Further features may also be incorporated in these various aspects. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to one or more of the illustrated embodiments may be incorporated into any of the above-described aspects of the present disclosure alone or in any combination. Again, the brief summary presented above is intended only to familiarize the reader with certain aspects and contexts of some embodiments without limitation to the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages of certain embodiments will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
         FIG. 1  generally depicts a production system having devices with robotic manipulators in accordance with one embodiment; 
         FIGS. 2 and 3  are perspective views of a robotic manipulator in the form of an articulated robotic arm with a gripping tool in accordance with one embodiment; 
         FIGS. 4 and 5  are perspective views of an articulated robotic arm like that of  FIGS. 2 and 3 , but with both a gripping tool and a torque tool, in accordance with one embodiment; 
         FIG. 6  is a perspective view of a subsea manifold having a robotic arm for facilitating support operations for the subsea manifold in accordance with one embodiment; 
         FIG. 7  is a plan view of the subsea manifold and robotic arm of  FIG. 6 ; 
         FIG. 8  depicts the robotic arm of  FIGS. 6 and 7  in an extended position during a support operation, with a gripping tool of the arm facing the subsea manifold, in accordance with one embodiment; 
         FIG. 9  depicts the robotic arm of  FIG. 8  with a torque tool of the arm facing the subsea manifold during a support operation in accordance with one embodiment; 
         FIG. 10  depicts the subsea manifold of  FIGS. 6 and 7  as having a tool box holding multiple, interchangeable tools that can be installed on the robotic arm in accordance with one embodiment; 
         FIG. 11  is a perspective view of the tool box of  FIG. 10 , shown isolated from the subsea manifold, in accordance with one embodiment; 
         FIG. 12  is a perspective view of the subsea manifold of  FIGS. 6 and 7  as having the tool box of  FIG. 11  mounted on the robotic arm in accordance with one embodiment; 
         FIG. 13  generally depicts various components with which a robotic manipulator may interact to perform support operations in accordance with one embodiment; and 
         FIG. 14  is a block diagram of a control system of a robotic manipulator in accordance with one embodiment. 
     
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
     Specific embodiments of the present disclosure are described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     When introducing elements of various embodiments, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Moreover, any use of “top,” “bottom,” “above,” “below,” other directional terms, and variations of these terms is made for convenience, but does not require any particular orientation of the components. 
     Turning now to the present figures, an apparatus  10  is illustrated in  FIG. 1  in accordance with one embodiment. The depicted apparatus  10  is a production system that facilitates extraction of a resource, such as oil or natural gas, from a subterranean reservoir. The apparatus  10  is generally shown in  FIG. 1  as a subsea production system having trees  12  (e.g., production or injection trees) coupled to wellheads  14  on a seabed. The wellheads  14  can include various components, such as casing heads, tubing heads, spools, and hangers, and the trees  12  can include valves for controlling fluid flow into and out of wells through the wellheads  14 . 
     Reservoir fluid can be produced from the reservoir through the wellheads  14  and the trees  12 , which are connected (e.g., via jumpers) to subsea manifolds  16  installed on the seabed. The manifolds  16  include valves to control flow of produced hydrocarbons or other fluids from the trees  12  through the manifolds  16 . The produced fluid can also be routed from the manifolds  16  to processing equipment. For example, produced fluid may be routed to a pump (or pumping station)  18  for adding energy to the produced fluid to facilitate delivery of the fluid through various flowlines or risers to some other location, such as a production platform, a floating production storage and offloading (FPSO) vessel, or an onshore processing facility. 
     Wells can be drilled into the seabed with a drilling rig, such as a drillship or semi-submersible, positioned above the seabed. In at least some instances, the drilling rig will be coupled to a blowout preventer stack  22  mounted on a wellhead  14  via a riser and a lower marine riser package  24 . As will be appreciated by those skilled in the art, the blowout preventer stack  22  can include ram-type and annular preventers, and the lower marine riser package  24  can include various control components for operating the preventers of the blowout preventer stack  22 . Additionally, the lower marine riser package  24  may itself include one or more preventers, such as an annular preventer. 
     A rotating drill string lowered from the drilling rig through the riser, the lower marine riser package  24 , the blowout preventer stack  22 , and the wellhead  14  may be used to bore a well. Once drilling of the well is finished, the well can be completed, the blowout preventer stack  22  and the lower marine riser package  24  can be disconnected, and a tree  12  can be mounted on the wellhead  14 . The tree  12  can be connected to a manifold  16  by a jumper, as discussed above, to enable fluid communication between the well and the manifold  16  through the tree  12 . 
     The apparatus  10  also includes robotic manipulators  26  coupled to various installed devices described above. More specifically, the apparatus  10  is depicted in  FIG. 1  as having robotic manipulators  26  on the trees  12 , the manifolds  16 , the pumping station  18 , the blowout preventer stack  22 , and the lower marine riser package  24 . These robotic manipulators  26  can be used to carry out various support functions for the installed devices. Several examples of such support functions include actuating valves, installing or retrieving components, inspecting the installed devices, and cleaning the installed devices, though the robotic manipulators  26  may facilitate other support functions. The robotic manipulators  26  can be controlled by human operators, but in some cases the manipulators  26  are provided as autonomous, smart devices programmed to perform various tasks with minimal input from human operators. 
     Some of the installed devices each include a single robotic manipulator  26 , though others (such as the manifolds  16  in  FIG. 1 ) may include multiple robotic manipulators  26 . In certain embodiments, a robotic manipulator  26  may include a robotic arm with a design that allows the arm to walk between multiple locations. This walking may be accomplished in any suitable manner, such as by gripping a fixed portion of an installed device with one end of the arm, disconnecting a base of the arm from the device, repositioning the base of the arm to a new location along the device, and reconnecting the base to the device at the new location. The tooling carried by the robotic manipulators  26  may vary depending on the support functions to be performed. In some instances, and as described in greater detail below, a robotic manipulator  26  includes multiple interchangeable tools to facilitate performance of a greater number of support functions for an installed device. 
     Although shown here as a subsea system, the apparatus  10  could take other forms in different embodiments, such as a topside system, an onshore system, or a system having any combination of subsea, topside, and onshore devices. It will be appreciated that the apparatus  10  can include various devices in addition to or in place of those depicted in  FIG. 1 , and that some devices noted above may be omitted in certain embodiments. The lower marine riser package  24  can be omitted from onshore embodiments, for instance. Further, the trees  12 , the wellheads  14 , the manifolds  16 , and various other devices of the apparatus  10  could be installed at a fixed location in an oil field or a gas field. For ease of reference, the term “oilfield devices” is used elsewhere herein to generically refer to devices intended for use in an oil field or a gas field. While certain examples of the use of robotic manipulators  26  for performing support functions for subsea devices are described below, it will be appreciated that robotic manipulators  26  can also be used to perform support functions for topside and onshore devices. 
     The robotic manipulators  26  can take any suitable form, but in at least some embodiments these robotic manipulators  26  are provided as robotic arms. By way of example, a robotic manipulator  26  may be provided in the form of a robotic arm  30  as depicted in  FIGS. 2 and 3 . In this embodiment, the robotic arm  30  includes a mounting base  32 , arm sections  34  and  36 , and a head  38 . The arm  30  can be attached to any of numerous different structures, such as various oilfield devices, via the mounting base  32 . This allows the arm  30  to act as an onboard remotely operated manipulator for the connected structure. 
     The depicted robotic arm  30  is an articulated arm with joints that provide rotational degrees of freedom and allow the arm to move and assist in numerous operations, examples of which are described below. As shown in  FIGS. 2 and 3 , a base joint  40  connects the arm section  34  to the mounting base  32 , the arm sections  34  and  36  are connected by an elbow joint  42 , and the head  38  is connected to the arm section  36  by a head joint  44 . The joints  40 ,  42 , and  44  allow the arm components connected by these joints to pivot with respect to one another. In some cases, for instance, the base joint  40  provides two rotational degrees of freedom between the mounting base  32  and the arm section  34 , the elbow joint  42  provides one rotational degree of freedom between the arm sections  34  and  36 , and the head joint  44  provides three rotational degrees of freedom between the arm section  36  and the head  38 . It is noted, however, that other arrangements in which one or more of the joints provide a different number of rotational degrees of freedom are also envisaged. Movement of the arm  30  can be accomplished with any suitable actuators. Electric motors (e.g., step motors) may be used to control rotation of various arm components in certain embodiments, though other actuators (e.g., hydraulic or pneumatic) could also or instead be used. 
     The robotic arm  30  includes at least one end effector for interacting with the device to which the robotic arm  30  is to be attached, such as an end effector for manipulating a component of a subsea manifold or of another oilfield device. For example, the robotic arm  30  depicted in  FIGS. 2 and 3  includes an end effector in the form of a gripping tool  48  having a pair of jaws for grasping objects. The arm  30  can be moved to position the head  38  near an object and the gripping tool  48  can be used to engage and manipulate the object in a desired manner. 
     The rotational degrees of freedom of the arm  30  facilitate positioning of the head  38  and the carried tool  48  alongside the manipulated object. More specifically, in at least some embodiments the rotational degrees of freedom of the arm  30  enable the end effector (e.g., the gripping tool  48  or some other tool) to have three translational degrees of freedom with respect to the device to which the arm  30  is attached. This is in contrast to alternatives allowing fewer than three translational degrees of freedom, in which movement of the end effector is more heavily constrained (e.g., two translational degrees of freedom) and in which a device with components to be manipulated is specially configured to accommodate the limited mobility of the end effector. 
     Although shown in  FIGS. 2 and 3  with the gripping tool  48 , the robotic arm  30  may also or instead carry other tools. For instance, the robotic arm  30  may also include a torque tool  52  on its head  38 , as depicted in  FIGS. 4 and 5 . This torque tool  52  can be used to rotate various components, such as to operate a valve actuator of an oilfield device. 
     Operation of the robotic arm  30  may be better understood with reference to  FIGS. 6-9 . As depicted in  FIGS. 6 and 7 , the robotic arm  30  is connected to an upper surface  54  of a subsea manifold  16 . In at least one embodiment, the robotic arm  30  is removably coupled to the subsea manifold  16  so as to permit the robotic arm  30  to be disconnected and separately retrieved from the manifold  16  while the manifold  16  is installed on a seabed. The robotic arm  30  may also be operated to assist in its own installation and retrieval in some cases. 
     The robotic arm  30  can be moved to facilitate various support functions, as noted elsewhere herein. For example, other devices (e.g., trees  12 , another manifold  16 , and the pumping station  18 ) can be connected in fluid communication with the manifold  16 , and the robotic arm  30  can be used to actuate valves of the manifold  16  to control fluid flow. In one such instance, the robotic arm  30  is moved from the resting position shown in  FIGS. 6 and 7  toward an extended position in which the head  38  of the arm  30  is positioned near a valve actuator  60 , as generally shown in  FIGS. 8 and 9 . In this extended position, the arm  30  can be lowered or raised to move an end effector toward or away from the actuator  60  (or any other component that is to be manipulated with the robotic arm  30 ). In conjunction with this movement of the arm  30 , the gripping tool  48  can be used to grasp and remove a debris cover  56  from the subsea manifold  16  to expose the valve actuator  60 , and the torque tool  52  can be used to control a valve by applying torque to the exposed actuator  60 . Once manipulation of the valve actuator  60  is complete, the debris cover  56  can be returned to its place over the valve actuator  60 . 
     The robotic arm  30  is depicted in  FIGS. 6-9  as having both the gripping tool  48  and the torque tool  52 . In this arrangement, the head  38  of the arm  30  can be rotated to generally alternate the positions of these tools with little movement of the rest of the arm  30 . But in other embodiments the robotic arm  30  may carry just a single tool at any given time. In some cases, multiple robotic arms  30  can be used to facilitate support operations, such as one robotic arm  30  with a gripping tool  48  and another robotic arm with a torque tool  52 . 
     In still other cases, a robotic arm  30  may be used with multiple, interchangeable end effectors (e.g., gripping tool  48 , torque tool  52 , and other tools) designed to perform different functions. These interchangeable end effectors may include any of a multitude of different tools that can be connected to and disconnected from the robotic arm  30  on an as-needed basis. When not in use, the interchangeable end effectors in at least some embodiments are positioned within reach of the robotic arm  30  to facilitate retooling of the arm  30  with different end effectors. The number and types of different, interchangeable end effectors can be selected by a user based on the support functions expected to be carried out by the robotic arm  30 . 
     The interchangeable end effectors are held by a tool box in at least some embodiments. As one example, a tool box  70  is shown in  FIG. 10  as coupled to the upper surface  54  of the manifold  16  near the robotic arm  30 . The depicted tool box  70  holds additional end effectors in the form of tools  72 ,  74 ,  76 , and  78 . These additional tools  72 ,  74 ,  76 , and  78  can include any of a variety of tools that facilitate desired support operations, such as gripping tools, torque tools, and spraying tools (e.g., water jet tools for cleaning) to name just a few examples. As best shown in  FIG. 11 , the tool box  70  includes individual slots  80  for holding the assortment of tools. 
     A tool (e.g., the gripping tool  48 ) carried by the robotic arm  30  can be disconnected from the robotic arm  30  and replaced with a different tool, such as one of the tools  72 ,  74 ,  76 , and  78 . In one automated retooling process, for example, the robotic arm  30  carrying a first tool is moved to insert the first tool into the empty slot  80  of the tool box  70  and the robotic arm  30  is disconnected from the first tool to leave that tool in its slot  80 . The arm  30  is then moved away from the first tool and into engagement with a second tool in the tool box  70  to enable the second tool to be carried in place of the first tool by the arm  30 . In this manner, the robotic arm  30  can fit itself with different tools appropriate for performing an array of desired support operations. It is noted, however, that in some other embodiments (e.g., in topside or onshore implementations) the tools can be interchanged manually by an operator. The tool box  70  can be positioned at any suitable location near the robotic arm  30 . In some instances, this can include mounting the tool box  70  on a portion of the robotic arm  30 , such as generally depicted in  FIG. 12 . 
     While certain examples of support tasks that can be performed with robotic manipulators  26  (e.g., the robotic arm  30 ) are described above, it is again noted that such robotic manipulators  26  can have many capabilities and can be used to enable a wide array of support functions. This versatility is generally represented in  FIG. 13 , in which an oilfield system  90  is shown to include a robotic manipulator  26  capable of interacting with numerous components. The system  90  can include one or more oilfield devices, which may be located subsea, topside, or onshore. The components depicted in  FIG. 13  are representative of components of such oilfield devices, and it will be appreciated that the oilfield devices can include any combination of these or other components with which the robotic manipulator  26  may interact. 
     More particularly, the robotic manipulator  26  can be used to facilitate installation or retrieval of many different components from a given installed device (e.g., a tree  12 , a manifold  16 , a pump  18 , or a blowout preventer stack  22 ). For example, the robotic manipulator  26  can be used for installing or retrieving (or otherwise manipulating) the following: various connectors  92 , which may include clamps; connector tooling  94 ; various seals  96 , such as hub seals; insulation doghouses  98 ; process compensation units  100 ; flowmeters  102 ; control modules  104 ; processing modules  106 ; sampling modules  108 ; hotstabs  110 ; lifting slings  112  (including, in one embodiment, manipulating shackles of a lifting sling); chokes  114 ; covers  116 , such as debris covers; umbilicals and flying leads  118 , such as electrical flying leads (EFLs), hydraulic flying leads (HFLs), steel flying leads (SFLs), umbilical termination heads (UTHs), optical flying leads (OFLs), and associated equipment; electrical distribution units  120 ; communication distribution units  122 ; intervention workover control systems (IWOCs)  124 ; acoustic detectors  126 ; accumulation modules  128 ; pigging loops  130 ; pig launchers and receivers  132 ; and valve actuators  134 . The robotic manipulator can also be used to operate valves  136  (e.g., mechanical operation of all override types), running tools  138  (for connection systems, control modules, etc.), other tools  140  (e.g., replacement and cleaning tools for connection systems), gasket test panels  142 , and locking mechanisms  144 . Still further, the robotic arm  30  or some other robotic manipulator  26  can perform on-demand inspection services (e.g., verifying valve indicators and bullseye inspection), cleaning (e.g., of the installed device and associated components), and cathodic protection point monitoring. 
     Several representative examples of such support operations are described in greater detail below for explanatory purposes. First, a robotic manipulator  26  (such as the robotic arm  30 ) can be used for valve intervention. As generally described above, the robotic manipulator  26  can be used to remove a debris cover, operate the valve (e.g., to open or shut the valve), and then replace the debris cover. The manipulated valves (e.g., valves  136 ) can be of any size, class, and override type (e.g., rotary, linear, or paddle type). 
     The robotic manipulator  26  can also be used for connection system intervention. In some instances, this may include using the robotic manipulator  26  to facilitate make up or disconnection of connectors  92 , such as by aligning a jumper and a running tool  138 , operating the running tool  138 , and installing and retrieving associated caps (e.g., covers  116 ). In other cases, the robotic manipulator  26  facilitates make up or disconnection of connectors  92  by aligning a jumper, operating a pull-in cylinder to set or break a connection, and installing or retrieving associated caps. 
     In another embodiment, the robotic manipulator  26  may be used to facilitate pigging operations. For instance, the robotic manipulator  26  can align and install a pigging loop  130  (e.g., on a subsea manifold) with running tools  138 , operate an isolation valve  136 , operate a gasket test panel  142 , and operate running tools  138  for retrieval of the pigging loop  130  after a pigging operation is completed. The robotic manipulator  26  can also be used to align and install a pig launcher and receiver  132 , operate an associated connection system, and operate the gasket test panel  142 . 
     The robotic manipulator  26  can also be used to install or retrieve flowmeters  102 , chokes  114 , or various modules, such as control modules  104 , processing modules  106 , sampling modules  108 , communication distribution units  122 , and accumulation modules  128 . Such support operations using the manipulator  26  may include removing a dropped object cover, aligning the module (or flowmeter) with an oilfield device, moving the module into engagement with the oilfield device, replacing the dropped object cover, and connecting one or more leads  118  (e.g., EFLs or OFLs) between the installed module and other components of the oilfield device. The robotic manipulator  26  can also be used to remove the dropped object cover, uninstall the one or more leads  118 , remove the module from the oilfield device, and replace the dropped object cover. In some cases, locking mechanisms  144  or other components may also be manipulated via the robotic manipulator  26  to facilitate installation or retrieval of a flowmeter, module, or other given component. 
     Certain additional features of a robotic manipulator  26  (e.g., a robotic arm  30 ) are generally depicted in  FIG. 14  in accordance with one embodiment. Particularly, the robotic manipulator  26  may be operated via a processor-based control system, an example of which is provided in  FIG. 14  and generally denoted by reference numeral  150 . In this depicted embodiment, the system  150  includes a processor  152  connected by a bus  154  to a memory device  156 . It will be appreciated that the system  150  could also include multiple processors or memory devices, and that such memory devices can include volatile memory (e.g., random-access memory) or non-volatile memory (e.g., flash memory and a read-only memory). The one or more memory devices  156  are encoded with application instructions  158  (e.g., software executable by the processor  152  to perform various functionality described above), as well as with data  160  (e.g., positions of, and other information about, components with which the robotic manipulator may interact). In one embodiment, the application instructions  158  are stored in a read-only memory and the data  160  is stored in a writeable non-volatile memory (e.g., a flash memory). 
     The system  150  also includes an interface  162  that enables communication between the processor  152  and various input or output devices  164 . The interface  162  can include any suitable device that enables such communication, such as a modem or a serial port. The input and output devices  164  can include any number of suitable devices. For example, in one embodiment the devices  164  include actuators  166  (e.g., step motors) for moving the robotic manipulator in a desired manner, cameras  168 , and sensors  170 . For instance, the robotic arm  30  can be fitted with one or more cameras  168  to facilitate operation of the arm  30  and on-demand visual inspection of nearby devices and components (e.g., a subsea oilfield device and associated components). The robotic manipulator  26  can include any desired sensors  170  and, in at least some embodiments, the sensors  170  include location or proximity sensors that may be used by the control system  150  for collision avoidance (i.e., to avoid unintentional collision of the robotic manipulator with some other object). Power and data may also be communicated between the robotic manipulator  26  and the structure to which it is attached, such as an oilfield device. For instance, electrical power, data, and operating commands may be provided to the robotic manipulator  26  from the structure (e.g., through the mounting base  32  of the robotic arm  30 ). Additionally, data may be communicated from the robotic manipulator  26  to the structure, from which it may be communicated to some other location, such as a topside or surface monitoring station. The actuators  166 , cameras  168 , and sensors  170  can be provided as part of the robotic manipulator  26 , though other devices  164  (e.g., human-machine interfaces) may be separate from the robotic manipulator  26 . 
     Use of the robotic manipulators  26  described above may allow a reduction in the use of small working class vessels in the field by providing on-demand inspection capabilities, by operating valves and other mechanisms on the installed devices, by facilitating installation and retrieval of most retrievable components, and by allowing cleaning of the installed devices by the robotic manipulators  26 . Further, the robotic manipulators  26  may also enable a reduction in overall weight of the installed devices, an increase in productivity (e.g., by allowing the onboard robotic manipulator to perform certain operations on demand, rather than waiting for intervention from an ROV), and a reduction in downtime of offshore installations and intervention campaigns. Although described above in connection with oilfield devices, it will be appreciated that the robotic manipulators  26  may be used with other, non-oilfield devices in full accordance with the present technique. 
     While the aspects of the present disclosure may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. But it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.