Patent Publication Number: US-10309576-B2

Title: System and method for pipe insertion in a pipeline

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional application Ser. No. 62/241,372 filed Oct. 14, 2015, the disclosure of which is hereby incorporated in its entirety by reference herein. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a system and method for pipe insertion in live gas mains. 
     BACKGROUND 
     The replacement of gas distribution pipe typically requires the excavation of trenches into which the pipe is laid. Alternatively, a technique known as pipe insertion provides a means for the installation of distribution pipe with reduced excavation, resources, permits and reinstatement costs. Pipe insertion is the process of inserting a smaller pipe into an existing, larger one. It currently provides a means for gas companies to cost-effectively replace large sections of main without the typical disruptive excavations. A “dead insertion” is a technique where a pipe is temporarily disconnected from the existing gas distribution network. Excavations are made at suitable access points on the existing gas main. A cut-out of an excavated section of main is created and a new polyethylene (PE) pipe is pulled or pushed into the section of existing main. 
     Each excavation associated with a pipeline replacement results in traffic delays, road closures and noise that disrupt the public and drive-up project costs. The high project costs may eventually be passed along to the gas customers. To minimize disruptions to service, it would be desirable to have an in situ means of connecting newly inserted PE pipe to service lines to eliminate the need to excavate over the connection point with the main at each service. 
     SUMMARY 
     Embodiments disclosed herein provide a system and method for pipe insertion in live gas mains. In at least some embodiments, a replacement pipe, for example one made from polyethylene, is inserted into a cast-iron pipe in need of rehabilitation. To avoid disruption of service, embodiments may provide a system and method for inserting a PE pipe while gas is still flowing to the end-users. A gas main may be accessed by a small excavation such that a portion of the main can be removed and a bypass inserted. This same process may be used at a location farther down the gas main so that a section of the gas main in need of rehabilitation is accessible from both ends. 
     A robotic device is then inserted into the isolated section and measurements taken to determine the location and orientation of service connections along the gas main. This data is then used to prepare a PE pipe, which may include drilling holes in the PE pipe which correspond to the locations of each service connection as measured by the robotic device, attaching a fitting over each hole at the desired locations along the pipe—for example, by fusing the fitting to the pipe—and optionally attaching spacers on the outside of the pipe to keep it centered as it is inserted into the gas main. The prepared PE pipe is then inserted into the isolated section of the gas main. A small robotic device is then inserted into a flexible PE liner pipe sized appropriately to fit into the existing service line. 
     The small PE liner pipe is inserted into the existing service line, which may be accessed, for example, by disconnecting the service line from the meter and inserting the PE liner pipe at the disconnected service line pipe. Alternatively, a small excavation may be made off the roadway—e.g., in the grass, garden or front yard of the building—to access the service line leading to the main. The small PE line pipe is urged through the existing service line until the robotic device contacts and makes the connection with the fitting fused onto the PE pipe within the gas main. Prior to contacting the gas main, the robotic device may be used to cause the PE liner pipe to bend around one or more 90-degree elbows, which commonly comprise the service and the service tee. The robotic device can then be removed from the small PE liner pipe in the existing service line and final termination of the service line to, for example, a gas meter can then be made. This process is repeated for other service lines connected to the isolated portion of the gas main. Once this is complete, the two ends of the PE pipe inserted into the gas main are connected to their corresponding ends of the cut gas main. The bypasses previously inserted can now be removed and gas routed through the newly inserted PE pipe in the gas main and the service pipes connecting to it. 
     Embodiments described herein may include a method for measuring distance in a pipeline, including some or all of the following steps: a) disposing a first subsystem of a robotic measuring system into the pipeline at an opening in the pipeline; b) disposing a second subsystem of the robotic measuring system into the pipeline at a first position such that there is a line of sight between the first and second subsystems; c) actuating a measurement capture process by the robotic measuring system, the measurement capture process including generating a laser beam from one of the first or second subsystems and reflecting it from the other of the first or second subsystems to generate a distance measurement between the first and second subsystems; d) moving the first subsystem to a position closer to the second subsystem; e) actuating the measurement capture process; f) moving the second subsystem to a position away from the first subsystem such that there is a line of sight between the first and second subsystems; and g) actuating the measurement capture process. 
     Embodiments described herein may include a method for measuring distance in a pipeline, including a method for measuring distance in a pipeline. The method may include opening the pipeline at a first location and opening the pipeline at a second location disposed at a longitudinal distance from the first location. A first subsystem of a robotic measuring system may be disposed into the pipeline at a known location, and a second subsystem of the robotic measuring system may be disposed into the pipeline such that there is a line of sight between the first and second subsystems. A measurement capture process may be actuated by the robotic measuring system to generate a distance measurement between the first and second subsystems. The measurement capture process may include generating a laser beam from one of the first or second subsystems and reflecting it from the other of the first or second subsystems. The first and second subsystems may be alternately moved in the same direction along a length of the pipeline and the measurement capture process actuated after each movement of the first and second subsystems. 
     Embodiments described herein may include a system for measuring distance in a pipeline. The system may include a first subsystem of a robotic measuring system that includes a laser generator and is operable to move along an inside of the pipeline. A second subsystem of the robotic measuring system includes a reflector for reflecting a laser generated by the first subsystem and is operable to move along the inside of the pipeline. A locating arrangement is attached to one of the first or second subsystems and is configured to locate a feature of interest on the inside of a pipeline. 
     Embodiments described herein may include a system for pipe insertion into a pipeline. The system may include a service line robotic system having an actuator head arrangement defining a center line and movable along at least two axes transverse to the center line and configured for attachment to a flexible pipe such that an end of the flexible pipe moves along the at least two axes with the actuator head arrangement. A control system may be operatively connected to the actuator head arrangement and operable to move the actuator head arrangement along the at least two axes. 
     Embodiments described herein may include a system for pipe insertion into a pipeline. The system may include a service line robotic system having an actuator head arrangement configured to engage a flexible pipe and move the flexible pipe transversely relative to a longitudinal center line of the flexible pipe. A control system may be connected to the actuator head arrangement and operable to move the actuator head arrangement transversely relative to a longitudinal center line of the actuator head arrangement. 
     Embodiments described herein may include a method for pipe insertion into a pipeline that includes making a first excavation over a main pipeline to provide access to the main pipeline from above ground. A distance may be measured from a point in the first excavation to a service line connected to the main pipeline. A fitting may then be attached to a main liner pipe, and the main liner pipe inserted into the main pipeline through the first excavation until the fitting is aligned with the service line. The fitting may be attached on-site, off-site, or may be manufactured to specifications with the fitting placed at the desired location. A second excavation may be made over the service line to provide access to the service line from above ground, or access to the service line may be obtained by disconnecting the service line from a meter or some other above-ground fitting. A service line liner pipe may be inserted into the service line through the service-line access. A first end of the service line liner pipe may be manipulated through the service line and into the fitting attached to the main liner pipe. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-1B  show a flowchart illustrating a method in accordance with embodiments described herein; 
         FIG. 2  shows an initial excavation of a gas main; 
         FIG. 3  shows the insertion of a bypass line and stoppers into the gas main; 
         FIG. 4  shows removal of the cut section of the gas main; 
         FIG. 5  shows a second section of the gas main excavated and bypassed downstream from the first cut section; 
         FIG. 6  shows a reel of polyethylene pipe on a mobile computer control unit in accordance with embodiments described herein; 
         FIG. 7  shows a measurement robot ready for insertion into the gas main; 
         FIG. 8  shows the measurement robot at the end of the isolated section identifying a datum as a zero point for further measurements; 
         FIG. 9  shows the measurement robot working its way back toward the insertion point measuring the linear and radial positions of service connections; 
         FIG. 10  shows further measurement by the measurement robot; 
         FIG. 11  shows the computer control unit receiving data from the measurement robot; 
         FIG. 12  shows a valve attached to the opening of the gas pipeline for insertion of the PE pipe; 
         FIG. 13  shows the PE pipe being inserted into the isolated section of the gas main, and the PE pipe to being drilled at the measured location of a service line; 
         FIG. 14  shows a fitting being fused onto the PE pipe at the location of the drilled hole; 
         FIG. 15  shows a spacer being fused onto the PE pipe at a location near the fitting; 
         FIG. 16  shows the PE pipe being inserted into the gas main; 
         FIG. 17  shows the insertion of the PE pipe being stopped at a position such that the fittings align with the service lines leading to the building; 
         FIG. 18  shows a small excavation of a service line leading to the gas main; 
         FIG. 19  shows a control valve and pipe pusher installed on the service line; 
         FIG. 20  shows a robotic device for use in conjunction with connecting the service line to the gas main; 
         FIG. 21  shows the robotic device being inserted into a small-diameter flexible PE pipe; 
         FIG. 22  shows the robotic device connected to the flexible small-diameter PE pipe; 
         FIG. 23  shows the robotic device and small-diameter PE pipe being inserted into the service line; 
         FIG. 24  shows the robotic device making a connection with the fitting that was previously fused to the PE pipe inserted into the gas main; 
         FIG. 25  shows the annular space around the small-diameter PE pipe in the service line being filled with a sealant; 
         FIG. 26  shows the downstream end of the PE pipe inserted into the main connected to the cut section of the gas main adjacent to it; 
         FIG. 27  shows the upstream end of the PE pipe inserted into the main connected to the cut section of the gas main adjacent to it so that gas is now able to flow through the PE pipe; 
         FIG. 28  shows a perspective view of a subsystem of a robotic measuring system operable to emit a laser beam to provide linear measurements; 
         FIG. 29  shows a perspective view of another subsystem of the robotic measuring system equipped with a reflector to work in conjunction with the subsystem shown in  FIG. 28  to provide various measurements; 
         FIG. 30  shows a schematic illustration of a stepwise process for determining linear measurements using the robotic measuring system; 
         FIG. 31  shows an actuator head arrangement as part of a service line robotic system; 
         FIG. 32  shows a portion of a control system that can be used for controlling the actuator head arrangement; 
         FIG. 33  shows detailed workings of the control system shown in  FIG. 32 ; 
         FIG. 34  shows a perspective view of a feeder system for feeding a flexible pipe in accordance with embodiments described herein; and 
         FIG. 35  shows the feeder system operating on a piece of corrugated flexible pipe. 
     
    
    
     DETAILED DESCRIPTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
       FIGS. 1A-1B  show a flowchart  10  illustrating the steps in accordance with at least some embodiments described herein. The steps of the method  10  are now explained in more detail in conjunction with  FIGS. 2-27 . At step  14 , an excavation  147  is made in the street to access a portion of a gas main  148  in order to isolate a section  150  of the gas main  148 —see  FIG. 2 . Also shown in  FIG. 2  are service lines  152 ,  154 , which are respectively connected to gas meters  156 ,  158 .  FIG. 3  illustrates steps  16  and  18 , wherein bag stoppers  160 ,  162  are inserted into the gas main  148 , and a bypass  164  is also installed.  FIG. 4  shows the section of the pipeline  148  removed as set forth in step  20 . This process is essentially repeated at a point several meters downstream from the original excavation, except that a receiving gland  166  is inserted on one end of the gas main prior to removing the bag stoppers—see  FIG. 5 , showing a service line  149  connected to a gas meter  151 . Another excavation  153  is made, a section of the main  148  is removed, and a bypass  155  is installed. Shown in  FIG. 6  is a mobile computer control unit  168 , which contains a reel of PE pipe  170 , a computer control unit  172 , and tools  174  for drilling and applying fittings to the PE pipe  170 . 
       FIG. 7  shows a gas main measurement robot  176  ready for insertion into the gas main  148  at the site of the first excavation  147 . The robot  176  is contained in a launch tube  178 , which allows it to enter the pipeline  148  through a valve without allowing gas to escape. The measurement robot  176  is moved down to the end of the isolated section of the pipeline  148  until it reaches the receiving gland  166 . Here, the measurement robot  176  identifies a zero datum, which may be the end of the pipe or some other convenient reference, as the basis for future measurements. In  FIGS. 9 and 10 , the measurement robot  176  is moving back down the pipeline  148  towards its entry point, and it is identifying the linear and radial locations of the service connections, for example service lines  180 ,  182 , so that appropriate connections can be made with the PE pipe. This process is generally described in steps  22 - 28  in the flowchart  10 . 
     As shown in  FIG. 11 , the data from the measurement robot  176  is analyzed by the computer control unit  172 .  FIG. 12  shows a gland box  184  attached to the cut end of the main  148 . The gland box  184  allows insertion of the PE pipe  170  into the live gas main by maintaining a seal even as the PE pipe  170  is inserted through it. The gland box  184  may contain two walls which can be independently opened and closed, and which define an interior chamber. Alternatively, a gland box, such as the gland box  184 , may contain one or more flanges with openings that conform to the shape of the PE pipe  170  and thereby form a seal. Either of these configurations allows entry of the PE pipe  170  into the main with a minimal release of gas to the ambient environment. Before or after a portion of the PE pipe  170  has been inserted into the gas main, a first service tap is drilled into the PE pipe  170  as shown in  FIG. 13 . A fitting  186  is then fused onto the PE pipe  170  at the point of the drilled hole as shown in  FIG. 14 . At a location near the fitting  186 , a spacer  188  may also be attached—for example by fusing—to the outside of the PE pipe  170 ; this helps to keep the PE pipe  170  centered within the gas main  148  after it has been inserted. 
     In the embodiment shown in  FIG. 13 , the attachment of the fittings, the drilling operation, and the attachment of spacers takes place on-site; however, in other embodiments, a pipe, such as the PE pipe  170 , may have fittings and spacers attached and holes drilled off-site so that it is ready to be inserted when it is delivered to the work site. A liner pipe may even be manufactured with fittings, spacers, or both, positioned at desired locations. At a minimum, a liner pipe may be manufactured with apertures—e.g., round holes, square holes, slots, etc.—disposed at predetermined locations in a wall of the liner pipe. In its simplest form, the fitting may be an aperture only, but will often include a seal for the connection to a service line liner pipe as described below. Apertures or other elements of the fittings may be performed, for example, in one or more secondary manufacturing operations after the tubular portion of the liner pipe is extruded or otherwise formed. And although polyethylene pipe is used in this example as the liner pipe, other embodiments may use liner pipes made from different materials. 
     Once all of the holes are drilled, and the fittings and spacers fused onto the PE pipe  170 , the PE pipe is inserted into the gas main as shown in  FIG. 16 . Alternatively, the holes may be drilled, the fittings may be fused onto the PE pipe  170 , and the pipe may be inserted into the gas main in one continuous operation. The PE pipe  170  may be allowed to exit through the receiving gland  166  until the fittings are aligned with the service lines—see, e.g.,  FIG. 17  showing the fitting  186  aligned with the service line  180 . This process is described more specifically in the flowchart  10  at steps  30 - 56 . As described in step  58 , the PE pipe  170  can now be connected to the cut ends of the gas main and the PE pipe  170  gasified; alternatively, this step can be performed later in the process. The same is true for at least many of the other steps illustrated in the flowchart  10 —that is, many of them do not need to be performed in the precise order illustrated in the flowchart; rather, variations are contemplated within different embodiments described herein. 
       FIG. 18  shows a small excavation  188  made at a convenient location to access a service line  190 . A section  191  of the service line  190  is removed, and a control valve  192  and a pipe pusher  194  are attached to the downstream side of the service line  190 —see  FIG. 19 . Alternatively, the service line  190  may be accessed by disconnecting it from the meter  193 , shown in  FIG. 18 . In some cases, the meter may be inside a building, but it may still be possible to access the service line by disconnecting it from the meter. When the service line is disconnected from a meter, such as the meter  193 , a control valve and pusher may still be attached to the service line, such as illustrated and described in conjunction with  FIG. 19 . 
       FIG. 20  shows a remote service line connection robot  196 , and  FIG. 21  shows a small-diameter PE pipe  198  being inserted over a portion of the robot  196 . The robot  196  and PE pipe  198  are shown after connection in  FIG. 22 . The robot-end of the PE pipe  198  is then inserted into the service line  190  as shown in  FIG. 23 . The robot  196  is articulated to navigate until it reaches a fitting  200 , which has been previously fused into the PE pipe  170  as described above. The robot  196  facilitates the connection between the fitting  200  and the small-diameter PE pipe  198 ; the robot  196  is then removed. The annular space between the small-diameter PE pipe  198  and the service line  190  is filled with a sealant—which may be a caulk, grout or other material—as shown in  FIG. 25 . Also shown in  FIG. 25 , a splice  202  is made to connect a second piece  204  of the small-diameter PE pipe such that it can be connected to the gas meter or other building connection. 
     Shown in  FIG. 26  is the service line  180  after it has been connected to the PE pipe  170  in the gas main. A pressure test of the service line  180  may now take place, for example, via a membrane in the fittings or a stopper. Also shown in  FIG. 26 , the PE pipe  170  has been connected to the cut-end  206  with a fitting  208  so that gas can flow through the PE pipe  170  and the remainder of the gas main  148  that is still usable. Similarly, at the first excavation  147 , the PE pipe  170  is also connected to the other cut-end  210  of the gas main  148  with another of the valves  208 . Gas can now be routed through the good portions of the original gas main  148  and through the newly inserted PE pipe  170  and the small-diameter PE pipe leading up to each of the service connections—e.g., the PE pipe  198 ,  204  shown in  FIG. 25 . The steps of connecting the service lines and finalizing the connection of the gas main are described in more detail in steps  60 - 86  of the flowchart  10 . 
     In  FIG. 7 , a measurement robot  178  was illustrated and described as a way to provide measurements along the pipeline  148  to locate the connection points of the service lines—e.g., the service lines  152 ,  158 , etc. In at least some embodiments, a robotic measuring system may include two subsystems that work together to provide the desired measurements.  FIG. 28  shows a first subsystem  210  of a robotic measuring system. The subsystem  210  includes a laser generator module  212  configured to generate a laser beam  214 . A set of drive wheels  216 ,  218  are operable to move the subsystem  210  along an inside of a pipeline, such as the pipeline  148 . In the embodiment shown in  FIG. 28 , wheels  220 ,  222  are driven, but in other embodiments may also be drive wheels. The laser generator  212  is mounted on a two-piece gimbal drive  224 ,  226 , which provides an angular adjustment for the laser generator  212 . 
     The first subsystem  210  also includes a pair of idler wheels  228 ,  230 . The idler wheels  228 ,  230  are mounted on a pivoting support structure  232 , which may be pivoted by a pneumatic actuator  234 . In this way, the idler wheels  228 ,  230  are adjustable away from the drive wheels  216 ,  218  to bring the idler wheels  228 ,  230  into contact with the opposite side of the pipeline from the drive wheels  216 ,  218 . In the embodiment shown in  FIG. 28 , the idler wheels  228 ,  230  are located between the drive wheels  216 ,  218  and the driven wheels  220 ,  222 , and provide an opposing force that stabilizes the subsystem  210  in the pipeline. 
       FIG. 29  shows a second subsystem  236  making up a part of the robotic measuring system. Similar to the first subsystem  210 , the second subsystem  236  includes a set of drive wheels  238 ,  240 , a set of driven wheels  242 ,  244 , and a set of idler wheels  246 ,  248 . The idler wheels  246 ,  248  are also mounted on a pivoting support structure  250 , which is pivoted by a pneumatic actuator  252 . As described in more detail below, the second subsystem  236  works in conjunction with the first subsystem  210  to provide measurements of features of interest in a pipeline, such as the pipeline  148 . The second subsystem  236  includes a reflector  254  and an array of photo sensors  256  positioned proximate to the reflector  254 . The reflector  254  is configured to receive the laser beam  214  and reflected back so that an accurate measurement can be made of the distance between the first and second subsystems  210 ,  236 . 
     The reflector  254  and photo sensor array  256  are mounted on a two-piece gimbal drive  258 ,  260 . The gimbal drive also provides angular adjustment for the reflector  254  and photo sensor array  256 , so that a direct line of sight between the laser beam  214  and the reflector  254  can be achieved. If the laser beam  214  is not centered on the reflector  254 , one or more of the photo sensors  256  will be hit by the laser beam  214 , and appropriate adjustment can be made to one or both of the laser generator  212  or the reflector  254 . 
     The second subsystem  236  also includes a locating arrangement  262  attached to it that is configured to locate a feature of interest inside a pipeline, such as the pipeline  148 . In the examples illustrated and described above, a feature of interest may be, for example, a connection point of a service line to the pipeline. In the embodiment shown in  FIG. 29 , the locating arrangement  262  is configured as an elongated member  264  having an aperture  266  disposed therethrough to allow gas to pass through the aperture  266  when the elongated member  264  is disposed over a connection point between a service line in the pipeline. The elongated member  264  also includes a conical top portion  268 , which further facilitates positively identifying a service line connection point. As the second subsystem  236  is moved along the inside of a pipeline, the elongated member  264  contacts an inside wall of the pipeline and the conical top portion  268  enters into the opening of a service line connection point. This provides the operator a radial location of the service line connection. In this way, at least some embodiments of the robotic measuring system can provide both linear and radial measurements. 
     There are a number of ways in which a robotic measuring system having first and second subsystems, such as the subsystems  210 ,  236 , can be used effectively for pipe insertion into a pipeline and connections to service lines such as described above. Of course, it is understood that this application is not the only situation in which such robotic measuring system is effective or desirable. Almost any application where accurate linear measurement is desired, and in particular, where access to the measured location is difficult, such a robotic measuring system may be effective and desirable. For purposes of describing a method of using such a robotic measuring system, the previous application of inserting a pipe into a pipeline and connecting it with service connections will be used as an example. 
     As shown in  FIG. 2 , a first excavation  147  is made to access the pipeline  148 . A section of the pipeline  148  is removed and the appropriate plugs and bypass installed—see  FIG. 4 . At some distance along the pipeline  148 —for example several meters, or in some cases approximately 100 m—a second excavation  153  is made. Here a section of the pipeline  148  is also removed and the appropriate plugs and bypass installed. In the following description of methods for using the first and second subsystems  210 ,  236 , one of the subsystems  210 ,  236  will be initially placed at a known position—e.g., at one of the openings in the pipeline  148 —while the other of the subsystems  210 ,  236  is placed at some distance away when the measurements are taken and the process begins. It is understood, however, that the roles of the two subsystems  210 ,  236  could be reversed, and this will be apparent from the following description. 
     In at least one embodiment, the first subsystem  210  is disposed in the pipeline  148  at an opening in the pipeline such as, for example, would be accessible at the second excavation  153 . The second subsystem  236  is disposed into the pipeline  148 , for example, at an opening accessible at the first excavation  147 . The second subsystem  236  is driven down the pipeline  148  until it is within a desired distance from the first subsystem  210 . More particularly, the second subsystem  236  will be positioned relative to the first subsystem  210  to ensure that there is a direct line of sight between the first and second subsystems  210 ,  236 . In at least some examples, this may be approximately 3 m. A measurement capture process is then actuated, by generating the laser beam  214  such that it reflects from the reflector  254  to generate a distance measurement between the first and second subsystems  210 ,  236 . 
     After this first distance measurement is taken, the first subsystem  210  is moved to a position closer to the second subsystem  236 , which in some examples may be approximately 0.5 m. The measurement capture process is again actuated and the distance between the two subsystems  210 ,  236  is measured. Next, the second subsystem  236  is moved to a position away from the first subsystem  210  such that there is still a line of sight between the first and second subsystems  210 ,  236 . In at least some situations this may again be approximately 3 m. The measurement capture process is again actuated and a distant measurement taken. These steps are repeated wherein the first subsystem  210  moves close to the second subsystem  236 , a measurement is taken, and then at the second subsystem  236  moves farther away while still maintaining a line of sight, and another measurement is taken. The stepwise method described above alternately moves the first and second subsystems  210 ,  236  along a length of the pipeline and actuating the measurement capture process after each movement of the first and second subsystems  210 ,  236 . 
     After the final movement of the second subsystem  236 , the measurements comprise a series of long and short measurements. The distance from the starting point of the first subsystem  210 —for example, at the opening of the pipeline in the second excavation  153 —to the location of the second subsystem  236  is calculated by mathematically combining all of the distant measurements previously taken. More specifically, all of the long measurements are added and all of the short measurements are subtracted, and the desired distance is determined. This concept is illustrated schematically in  FIG. 30 . In the first step  261 , “Position A” is occupied by the first subsystem  210  and “Position B” is occupied by the second subsystem  236 . After this measurement is obtained, the first subsystem  210  moves to a new position—i.e., “Position C”—while the second subsystem  236  remains at Position B and another measurement is taken—this is shown in step  263 . Finally, the second subsystem  236  moves away from the first subsystem  210  to a location designated as “Position D”—this is shown at step  265 . The desired distance “AD” is obtained from the following equation: AD≈AB+CD−CB. 
     As described in detail above, connecting the fittings to the PE pipe, such as the PE pipe  170 , at the appropriate locations requires knowledge of where the service lines connect to the pipeline  148 . This is where the locating arrangement  262  can be used. For example, as the second subsystem  236  is moving away from the first subsystem  210  during one of the iterations of measurement described above, the locating arrangement  262  may, upon a service line connected to the pipeline  148 . When this happens, the second subsystem  236  stops and a line of sight between the laser beam  214  and the reflector  254  is established. A measurement is taken and the position of the locating arrangement  262  relative to the opening in the pipeline  148  at the second excavation  153  can then be determined as described above. This distance can be used to appropriately place a fitting onto the PE pipe  170 . The PE pipe  170  can then be inserted into the pipeline  148  so that the fitting aligns with the service line connection point. 
     Once a fitting, such as the fitting  186  is aligned with a service line, such as the service line  180 —see  FIG. 17 , a service line robotic system can be used. One such system that included a remote service line connection robot  196  was described above and illustrated in conjunction with  FIGS. 20-24 .  FIGS. 30-34  show another embodiment of a service line robotic system that may be used for pipe insertion into a pipeline such as described above. An actuator head arrangement  270  forming part of a service line robotic system is shown in  FIG. 31 . The actuator head arrangement defines a center line  272 , which is a longitudinal centerline of the actuator head arrangement  270 . Although it is shown as being straight in the illustration shown in  FIG. 31 , the actuator head arrangement  270  is movable along at least two axes transverse to the centerline  272 , and it is understood that the centerline  272  will at times be curved. 
     The actuator head arrangement  270  includes several pivotable sections  274 ,  276 ,  278 ,  280 , which, in the embodiment shown in  FIG. 31 , are configured as “universal joints” and pivot around two axes perpendicular to the centerline  272 . For example, the pivotable section  276  is pivotable about an axis  282 , which is directed into the page as shown in  FIG. 31 , and an axis  284 , which is vertical as shown in  FIG. 31 . Although the transverse axes  282 ,  284  are perpendicular to the centerline  272 , in other embodiments and actuator head arrangement, such as the actuator head arrangement  270  may be movable in other directions. At the front and of the actuator head arrangement  270 , is a nose section  286 , which includes at least one camera  288  and at least one light  290 . 
     Shown by the partial cut-away view of  FIG. 31  are control cables  292 ,  294 . Although only two of the cables  292 ,  294  are visible in  FIG. 31 , it is understood that two other similarly configured control cables are disposed directly behind the cables  292 ,  294 —see, also,  FIG. 20  where four control cables  296 ,  298 ,  300 ,  302  are shown. The service line robotic system also includes a control system  304  as shown in  FIG. 32 . The control system  304  is connected to the actuator head arrangement  270  through the control cables  292 ,  294 ,  306 , and one other control cable not visible in  FIG. 32 . The control system  304  includes a display  308  operatively connected to the camera  288  to provide visual feedback to an operator from the camera  288 . Communications between the control system  304  and the camera  288  may be facilitated by an electrical cable running adjacent to the control cables  292 ,  294 ,  306 . The electrical cable may facilitate video transmission between the display  308  and the camera  288 ; it may also provide control communications and even power for the camera  288  and the light  290 . Similar to the robot  196  illustrated in  FIG. 20 , the actuator head arrangement  270  is configured for attachment to, and more specifically for insertion into, a flexible pipe, such as the smaller diameter PE pipe  198 . This is the pipe that will be inserted through a service line, such as the service line  190 . 
       FIG. 33  shows the control system  304  with the display  308  removed for visibility of some of its features. The control system  304  includes a support structure  310  made up of a number of plates and other structural members mounted inside a housing  312 . Each of the control cables  292 ,  294 ,  306 , and the fourth control cable are connected to the support structure  310  at one end, and the actuator head arrangement  270  at the other end. As noted above, an electrical cable for communications, power, or both, also runs between the control system  304  and the actuator head arrangement  270 . The control system  304  is configured to selectively apply tension to and release tension from at least some of the control cables to move the actuator head arrangement  270  transversely to the centerline  272 , for example, along the two axes  282 ,  284 . To effect the application and release of tension on the control cables, the control system  304  includes four motors  314 ,  316 ,  318 ,  320 . The motors  314 ,  316  turn respective drive screws  322 ,  324 , which in turn move respective carriages  326 ,  328  linearly because the carriages  326 ,  328  have drive nuts inside their housings. 
     Also shown in  FIG. 33  as a battery  330  used to provide power to the motors  314 ,  316 ,  318 ,  320 , and various control and drive electronics  332 , which may contain one or more microprocessors, memory, firmware, software or some combination of these. Each of the control cables includes a wire surrounded by a sheath. For example, the cable to  294  includes a wire  334  visible inside the housing  312  and a sheath  336  outside the housing  312 . Similarly,  FIG. 31  shows the wire portion  334  of the cable to  94  disposed within the pivotable sections  274 ,  276 ,  278 ,  280 , while the sheath portion  336  is shown outside the pivotable portions to  74 ,  276 ,  278 ,  280 . In fact, the sheaths from the control cables terminate at a back section  338  of the actuator head arrangement  270 . To manipulate the actuator head arrangement  270 , and therefore the end of a flexible pipe, such as the PE pipe  198 , it is the inner wires of the control cables that are tensioned or released from tension. 
     As shown in  FIG. 32 , the control system  304  includes a pair of manipulators  340 ,  342 , which in this embodiment are joysticks movable along to perpendicular axes. In order to move the actuator head arrangement  270  in a particular direction, the pair of cables disposed toward the direction of movement have tension applied to them, while the two opposing cables have tension released from them. The joystick  342  can be actuated to apply tension to or release tension from the two cables  292 ,  306 , while the joystick  340  can be actuated to apply tension to or release tension from the cable to  94  and the fourth cable disposed behind the cable  306 . Moving the joysticks  340 ,  342  along the opposite axes, however, manipulates different pairs of cables so that the actuator head arrangement  270  can be articulated up and down, as well as left and right. 
     In order to move the flexible pipe longitudinally through a service line, such as moving the PE pipe  198  through the service line  190 —see  FIG. 21 —the service line robotic system also includes a feeder arrangement  344  as shown in  FIGS. 33 and 34 . The feeder arrangement  344  is configured to engage flexible pipe, such as the PE pipe  198 , and it is operable to move the flexible pipe longitudinally. The feeder arrangement  344  includes two hinged portions  346 ,  348 , which can be opened and closed to provide easy access for an adapter  350 , which will guide the flexible pipe. The feeder arrangement  344  includes drive wheels  352 ,  354  in the first portion  346 , and drive wheels  356  and one other drive wheel not visible in  FIG. 34  in the second portion  348 . In this embodiment, the drive wheels  352 ,  354 ,  356  have generally concave teeth. In  FIG. 35 , one type of flexible pipe  358  is shown, and includes convex ridges  360  that are engaged by the toothed wheels  352 ,  354 ,  356 . 
     Drive motors  362 ,  364  respectively provide power to the first and second portions  346 ,  348  for rotating the wheels  352 ,  354 ,  356  to move the flexible pipe  358  longitudinally through, for example, a service line. The flexible pipe  358  includes a longitudinal centerline  366 . When an actuator head arrangement, such as the actuator head arrangement  270  is inserted into the flexible pipe  358 , the actuator head arrangement and the end of the flexible pipe  358  will have a common longitudinal centerline. As the actuator head arrangement  270  is steered around the various bends and turns by the control system  304 , the end of the flexible pipe  358  will be steered along with it. Thus, the feeder arrangement  344  provides longitudinal movement while the control system  304  provides articulation in other directions such that the end of the flexible pipe  358  can be inserted into a fitting and a main pipeline pipe liner, such as shown in  FIG. 24 . In this way, robotic measurement system and service line robotic system may be used together to line the inside of pipelines and service lines with minimal excavation. 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.