Method for detecting the location of connection ports in existing pipes

Abstract

This invention provides a method for accurately detecting the location of the connection port of an existing pipe after lining a rehabilitated pipe. [Solution] A method for detecting the position of the connection port 15 from the inside of the rehabilitated pipe 20, with the rehabilitated pipe 20 lined on the inner circumference of the existing pipe 10 and the connection port 15 sealed, comprises a preparation step performed prior to lining and a main step performed after lining. In the preparation step, a vehicle 31 equipped with an electromagnetic induction type detector 35 and a video camera 32 is driven along the existing pipe 10 until the pipe axis position of the video camera 32 coincides with the connection port 15. The count value of the annular reinforcing bars 11 of the existing pipe 10 detected by the detector 35 is obtained, and the travel distance is measured, and this information of reinforcing bar count values ​​and travel distance is recorded. In the main step, the vehicle 31 is driven along the rehabilitated pipe 20, and the information of the reinforcing bar count values ​​and travel distance detected by the detector 35 is compared with the information recorded in the preparation step to estimate the pipe axis position of the connection port 15.

Description

Technical Field

[0001] The present invention relates to a method for detecting the position of a connection port for connecting a mounting pipe in an existing pipe from the inside of a rehabilitation pipe after lining the inner circumference of the existing pipe with the rehabilitation pipe.

Background Art

[0002] Connection ports are formed in existing pipes such as sewer pipes, and mounting pipes are connected to these connection ports. When an existing pipe deteriorates, it is rehabilitated by lining the existing pipe with a rehabilitation pipe. However, when the rehabilitation pipe is lined, the connection ports of the existing pipe are blocked by the rehabilitation pipe, so communication ports continuous with the connection ports must be formed in the rehabilitation pipe.

[0003] When forming a communication port from the inside of the rehabilitation pipe, it is necessary to detect the position of the connection port blocked by the rehabilitation pipe. The conventionally implemented detection method includes a preparation step executed before lining the existing pipe with the rehabilitation pipe and a main step executed after lining the rehabilitation pipe.

[0004] In the above preparation step, a cable wound around a reel is pulled out and its tip is connected to a traveling vehicle. A video camera is installed on the traveling vehicle. The operator monitors the video of the video camera while running the traveling vehicle along the pipe axis direction from the pipe end of the existing pipe, and stops the traveling vehicle when the center of the field of view of the video camera coincides with the connection port. The traveling distance of the traveling vehicle corresponds to the length of the cable pulled out, and this pulled-out length can be obtained, for example, by multiplying the number of rotations of an intermediate pulley around which the cable is spanned by the pulley circumference. The distance from the pipe end of the existing pipe to the connection port corresponds to a value obtained by adding the traveling distance of the traveling vehicle to the distance in the pipe axis direction between the cable connection point of the traveling vehicle and the video camera installation point.

[0005] In the above process, for example, the vehicle used in the preparation process can be used. Similar to the preparation process, the distance traveled by the vehicle is measured as the cable pull-out length. The vehicle is driven along the pipe axis from the end of the rehabilitation pipe, and when the distance traveled matches the distance measured in the preparation process, the vehicle is stopped. At this time, it is estimated that the connection port is located in the field of view of the video camera, and a communication port is drilled.

[0006] Furthermore, Patent Document 1 discloses a method for detecting the cut location of a reinforcing bar using an electromagnetic detection means and estimating the position of the connection port from the detected cut location. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2022-54774 [Overview of the project] [Problems that the invention aims to solve]

[0008] In the conventional detection method described above, during the preparation step, the cable comes into contact with the corroded, uneven inner surface of the existing pipe, and therefore the cable length is affected by this unevenness. In contrast, during the main step, the cable length comes into contact with the smooth inner surface of the rehabilitated pipe and is not affected by the unevenness of the existing pipe's inner surface. As a result, even if the travel distance (cable length) measured in the preparation step and the main step is the same, the actual travel distance of the vehicle will differ. This difference accumulates over the long travel distance of the vehicle from the end of the existing pipe to the connection port. Consequently, the estimated location of the connection port deviates significantly from the actual connection port, potentially leading to mis-drilling or forcing the drilling to start with an extremely small blade diameter and gradually widen the opening area, resulting in a longer drilling time for the communication port.

[0009] In the detection method described in Patent Document 1, the location of the connection point can be accurately determined by detecting the cutting status of the reinforcing bar using an electromagnetic detection means. However, since only rough information about the location of the connection point is obtained in advance, a detailed detection operation must be started using the electromagnetic detection means from just before the connection point, which makes the detection operation time-consuming. [Means for solving the problem]

[0010] To solve the above problem, the present invention provides a method for detecting the position of a connection port from the inside of a rehabilitation pipe, in which a rehabilitation pipe is lined on the inner circumference of an existing reinforced concrete pipe having a connection port for connecting a branch pipe, and the connection port is blocked by the rehabilitation pipe. The process comprises a preparatory step performed prior to lining the rehabilitation pipe, and a main step performed after lining the rehabilitation pipe. In the preparation step, a vehicle equipped with an electromagnetic detection means is driven along the pipe axis of the existing pipe, and the annular reinforcing bars arranged at intervals in the pipe axis direction in the existing pipe are detected by the electromagnetic detection means to obtain a reinforcing bar count value, and the travel distance of the vehicle is measured by a travel distance measuring means, and the information regarding the reinforcing bar count value and the travel distance obtained until the pipe axis position of a specific part of the vehicle coincides with the pipe axis position of the connection port is recorded as information to identify the pipe axis position of the connection port. In the above-mentioned step, a vehicle equipped with an electromagnetic detection means is driven along the pipe axis of the rehabilitation pipe, the reinforcing bars are detected by the electromagnetic detection means to obtain a reinforcing bar count value, and the travel distance of the vehicle is measured by a travel distance measuring means. The position of the connection port in the pipe axis direction is estimated by comparing the information on the reinforcing bar count value and the travel distance obtained in the above-mentioned step with the information on the reinforcing bar count value and the travel distance recorded in the preparation step.

[0011] According to the method described above, by comparing the information on the rebar count and travel distance obtained in the main process after lining with the information on the rebar count and travel distance recorded in the preparation process before lining as information for identifying the pipe axis position of the connection port, it is possible to avoid the accumulation of differences in travel distance between the preparation process and the main process, the position of the connection port can be detected easily and accurately, mis-drilling of the communication port can be avoided, and the drilling work can be performed more easily.

[0012] In one embodiment, during the preparation step, the travel distance is recorded in association with the rebar count value each time a rebar is detected, and the travel distance measured until the pipe axis position of a specific part of the traveling vehicle coincides with the pipe axis position of the connection port is recorded as the travel distance to the connection port. In the main process, each time a rebar is detected, the travel distance associated with the rebar count value in the preparation process that matches the rebar count value in the main process is searched for, the travel distance measured in the main process is corrected to match the travel distance in the preparation process that was searched for, and the pipe axial position of the specific part when the travel distance in the main process reaches the travel distance to the connection port recorded in the preparation process is estimated to be the pipe axial position of the connection port. According to this method, the travel distance measured each time rebar is detected in the main process is corrected to match the travel distance in the preparation process, thus canceling out the difference in travel distance between the two processes.

[0013] Preferably in the above embodiment, the main step includes a comparison step each time a rebar is detected to determine whether the difference between the travel distance measured in the main step and the searched travel distance is within a predetermined range. If the comparison step determines that the result is positive, the travel distance in the main step is corrected to match the searched travel distance. If the comparison step determines that the result is negative, the rebar count values ​​in the preparation step are incremented by 1, and the travel distance associated with each rebar count value is re-searched. The comparison step then compares the travel distance in the main step with the re-searched travel distance. If the comparison step determines that the result is positive, the travel distance measured in the main step is corrected to match the re-searched travel distance, and the rebar count values ​​in the main step are corrected to match the incremented rebar count values. According to this method, even if there are any missed rebar detections in the main process, the rebar measurement values ​​in the main process can be adjusted to match the rebar count values ​​in the preparation process, and the travel distance can be corrected.

[0014] More preferably in the above embodiment, if, through repeated negative judgments in the comparison step, the travel distance associated with the rebar count value in the preparation step being compared becomes equal to or greater than the travel distance to the connection port recorded in the preparation step, the rebar count value in this step is maintained as the temporarily stored rebar count value, and the rebar count value is not updated when rebar is detected during subsequent travel. In the comparison step, the travel distance in this step is compared with the travel distance associated with the rebar count value in the preparation step which is equal to the temporarily stored rebar count value, and if a positive judgment is made in the comparison step, the travel distance in this step is corrected to match the travel distance in the preparation step, and the rebar count value in this step is set as the temporarily stored rebar count value. This method allows for adjustment of the travel distance and ensures that even if there are any missed rebar detections during the preparation process, the rebar measurement values ​​in the main process are matched to the rebar count values ​​in the preparation process.

[0015] In the above-described embodiment, the predetermined range is less than half the spacing between the reinforcing bars.

[0016] In another embodiment, in the preparation step, each time the electromagnetic detection means detects a reinforcing bar, the measured travel distance is cleared, and the reinforcing bar count obtained until the pipe axis position of the specific part coincides with the pipe axis position of the connection port, and the travel distance from the time the reinforcing bar immediately preceding the connection port was detected are recorded as information to identify the position of the connection port. In the above-mentioned process, each time the electromagnetic detection means detects a reinforcing bar, the measured travel distance is cleared, and the position of the specific part in the pipe axis direction when the reinforcing bar count value and the travel distance measured from the time of reinforcing bar detection match the reinforcing bar count value and the travel distance recorded in the preparation step are estimated to be the position of the connection port in the pipe axis direction. With this method, the travel distance is cleared each time rebar is detected in both the preparation and main processes, so there is no accumulation of differences in travel distance between the preparation and main processes.

[0017] In one embodiment, a portion of a signal transmission cable connected to the front of the vehicle is stretched across a pulley, and a rotary encoder for detecting the rotational speed of this pulley is provided as the means for measuring the distance traveled.

[0018] In one embodiment, during the preparation step, a video camera is installed on the specific part of the vehicle, and the vehicle is driven so that the axial position of the specific part matches the axial position of the connection port based on the image of the connection port captured by the video camera. [Effects of the Invention]

[0019] According to the present invention, the location of the connection port of the existing pipe can be easily and accurately detected after lining the rehabilitated pipe, and consequently, the drilling of the communication port connected to the connection port can be performed efficiently. [Brief explanation of the drawing]

[0020] [Figure 1]In the method for detecting the position of a connection port of an existing pipe according to the first embodiment of the present invention, it is a schematic longitudinal sectional view showing a preparation process for determining the position of the connection port before lining the existing pipe with a rehabilitation pipe, and only the main part is shown by hatching. [Figure 2] It is a block diagram of control and calculation including a control calculation unit in a system for executing the first embodiment. [Figure 3] It is a flowchart of control and calculation executed in the preparation process of the first embodiment. [Figure 4] In the method according to the first embodiment, after lining the existing pipe with a rehabilitation pipe, it is a schematic longitudinal sectional view showing this process of estimating the position of the connection port, and only the main part is shown by hatching. [Figure 5] It is a flowchart of control and calculation executed in this process of the first embodiment. [Figure 6] It is a flowchart of control and calculation executed in the preparation process of the second embodiment of the present invention. [Figure 7] It is a flowchart of control and calculation executed in this process of the second embodiment.

Mode for Carrying Out the Invention

[0021] Hereinafter, the first embodiment of the present invention will be described with reference to FIGS. 1 to 5. <Outline of Rehabilitation Work of Existing Pipe> As shown in FIG. 1, the existing pipe 10 to be rehabilitated is, for example, an aging sewer pipe underground and has a reinforced concrete structure. In this embodiment, it is assumed that the inner diameter of the existing pipe 10 is such that a person cannot directly enter, for example, 800 mm or less. The existing pipe 10 is constructed by embedding an annular reinforcing bar 11 arranged at intervals in the pipe axis direction and a reinforcing bar (not shown) arranged at intervals in the circumferential direction and extending linearly in the pipe axis direction in a lattice-like connection state in concrete 12. One or more connection ports 15 are formed in the middle part of the existing pipe 10, and a mounting pipe 16 is connected to each connection port 15. Both ends of the existing pipe 10 are connected to manholes 1A and 1B.

[0022] As shown in Figure 4, the existing pipe 10 is rehabilitated by lining its inner circumference with a rehabilitated pipe 20. The rehabilitated pipe 20 is constructed, for example, by spirally winding a strip-shaped member made of synthetic resin and fitting the edges of adjacent wound portions together. The rehabilitated pipe 20 can be constructed in various forms; it may be constructed by connecting annular strips, using a resin tube with shape-retaining properties, or by curing a multilayer sheet such as a nonwoven fabric or glass fiber sheet with resin. The connection port 15 of the existing pipe 10 is sealed by lining it with the rehabilitated pipe 20.

[0023] After lining the rehabilitated pipe 20, a hole is drilled in the rehabilitated pipe 20 at a position corresponding to the connection port 15 of the existing pipe 10, thereby forming a communication port (not shown) that is connected to the connection port 15 and has approximately the same diameter as the connection port 15. This connects the mounting pipe 16 to the inside of the rehabilitated pipe 20.

[0024] In this embodiment, a preparation step and a main step are performed in order to drill a communication port so that it precisely matches the connection port 15 after lining the rehabilitation pipe 20. The preparation step is performed before lining the rehabilitation pipe 20 and is a step to accurately determine (identify) the position of the connection port 15. The main step is a step to estimate the position of the connection port 15 determined in the preparation step and drill a communication port after lining the rehabilitation pipe 20.

[0025] <System configuration for executing the preparation process> As shown in Figure 1, the system for performing the preparation process includes a movement detection device 30 that travels inside the existing pipe 10 and a base station 40 located on the ground near one of the manholes 1A.

[0026] The motion detection device 30 comprises a vehicle 31, a video camera 32 mounted on the vehicle 31, and an electromagnetic induction type detector 35 (electromagnetic detection means). The video camera 32 is supported by the vehicle 31 via a support 33 and a rotary drive unit 34. The rotary drive unit 34 rotates the video camera 32 about an axis extending in the direction of the pipe axis of the existing pipe 10, thereby moving the optical axis and field of view of the video camera 32 in the circumferential direction of the existing pipe 10. The mounting location of the video camera 32 at the tip of the rotary drive unit 34 provides a specific part on the vehicle 31.

[0027] The electromagnetic induction detector 35 is biased upward by a biasing mechanism 36 and moves along the inner surface of the top of the existing pipe 10 as the vehicle 31 moves. The biasing mechanism 36 includes, for example, a cylindrical body 36a that stands vertically from the vehicle 31, a rod 36b that hangs down from the electromagnetic induction detector 35 and is slidably inserted into the cylindrical body 36a, and a spring 36c that is positioned between the cylindrical body 36a and the electromagnetic induction detector 35. Since a roller 37 is provided at the upper end of the electromagnetic induction detector 35, the electromagnetic induction detector 35 does not directly rub against the inner surface of the existing pipe 10.

[0028] The base station 40 includes a pulley 42, a control calculation unit 43, a display unit 44, and an operation unit 45 installed inside the vehicle 41. The cable 46 wound around the pulley 42 is stretched across an intermediate pulley 47 supported at the rear of the vehicle 41 and an intermediate pulley 48 installed near the pipe end on the manhole 1A side of the existing pipe 10, and connected to the rear end of the vehicle 31. The cable 46 acts as a signal transmission line, with its base end connected to the control calculation unit 43 via the pulley 42, and its tip connected to the video camera 32, the rotary drive unit 34, the electromagnetic induction type detector 35, the vehicle drive unit 38 (shown only in Figure 2), and the rotation angle sensor 39 (shown only in Figure 2) of the vehicle 31.

[0029] The rotation angle sensor 39 is installed in the rotation drive unit 34 and is configured to detect the rotation angle of the video camera 32. The rotational speed of the pulley 47 is detected by a rotary encoder 49 (mileage measuring means). As the vehicle 31 travels, the cable 46 is pulled out, causing the pulley 47 to rotate, and the rotary encoder 49 detects the rotational speed of this pulley 47. The rotational speed of the pulley 47 includes information about the length of the cable 46 pulled out, and therefore also includes information about the distance traveled by the vehicle 31. In this embodiment, the rotary encoder 49 outputs one pulse for each rotation of the pulley 47.

[0030] Figure 2 is a block diagram for control and calculation, centered on the control calculation unit 43. The electromagnetic induction type detector 35 has an excitation coil 35a, a detection coil 35b, an excitation circuit 35c, and a detection circuit 35d. The excitation circuit 35c supplies alternating current to the excitation coil 35a in response to a command signal from the control calculation unit 43, thereby passing a magnetic flux through the reinforcing bar 11. The detection circuit 35d detects the current or voltage flowing through the detection coil 35b corresponding to the change in the magnetic flux of the reinforcing bar 11, and sends the detection signal to the control calculation unit 43.

[0031] The control calculation unit 43 receives video signals from the video camera 32 and displays the video on the display unit 44, and receives operation signals from the operation unit 45 to control the driving of the travel drive unit 38 and the rotation drive unit 34. In addition to the electromagnetic induction detector 35, the control calculation unit 43 also receives detection signals from the rotary encoder 49 and the rotation angle sensor 39 and performs the calculations described later.

[0032] <Details of the preparation process> Next, the control and calculation of the preparation process performed by the control calculation unit 43 will be explained with reference to Figure 3. The characteristic of this preparation process is that, taking into account that annular reinforcing bars 11 are arranged at intervals in the direction of the pipe axis in the existing pipe 10, the vehicle 31 is driven, and each time a reinforcing bar 11 is detected, the travel distance is stored in association with the count value (sequence; serial number) of the reinforcing bar 11 from the pipe end or its vicinity of the existing pipe 10, and the travel distance until the connection port 15 is detected is also recorded.

[0033] In Figure 3, N represents the count of connection ports 15 in the existing pipe 10, i.e., the order, counted from the pipe end on the manhole 1A side. M represents the count of reinforcing bars 11, i.e., the order of the reinforcing bars 11, counted from the pipe end on the manhole 1A side. L is the distance traveled by the vehicle 31 from the pipe end on the manhole 1A side.

[0034] In step 100, the system is initialized to N=1, M=1, and L=0. After this initialization, in step 101, the operator operates the control unit 45 to drive the drive unit 38, causing the vehicle 31 to travel along the pipe axis of the existing pipe 10, from the pipe end on the manhole 1A side toward the manhole 1B.

[0035] In the next step 102, the system waits for a pulse from the rotary encoder 49. When a pulse is received, the system proceeds to step 103, where the calculation L = L + Lp is performed. Here, Lp is the circumference of the pulley 47, and the result of this calculation is the length that the cable 46 is pulled out as the vehicle 31 moves, i.e., the distance traveled by the vehicle 31, L.

[0036] In the next step 104, it is determined whether the video camera 32 has reached the connection port 15. In this embodiment, this determination depends on the operator's actions. That is, the operator monitors whether the axial position of the video camera 32 coincides with the connection port 15 while viewing the video from the video camera 32 on the display unit 44. If they coincide, a coincidence signal is transmitted from the operation unit 45 to the control calculation unit 43. Note that the detection of the connection port 15 may be automated.

[0037] If no matching signal is received in step 104, the process proceeds to step 105, where it is determined whether the electromagnetic induction detector 35 has detected the reinforcing bar 11. If the determination is positive, the process proceeds to step 106, where the measured travel distance L is recorded as the travel distance LL(M) associated with the reinforcing bar count M (the Mth reinforcing bar 11), the reinforcing bar count value M is incremented by 1 in step 107, and the process returns to step 102. If the determination is negative in step 105, the process returns to step 102, and the measurement of the travel distance L continues.

[0038] When a matching signal is received in step 104, i.e., when connection port 15 is detected, the process proceeds to step 108 and the vehicle stops. In the next step 109, the measured travel distance L is recorded as the travel distance L(N) at the detection of the Nth connection port 15. In the next step 110, the number of connection port 15 is incremented by 1.

[0039] In the next step 111, if the center of the image on the display unit 44 is offset circumferentially from the center of the connection port 15, the operator operates the control unit 45 to drive the rotation drive unit 34, rotating the video camera 32 around an axis extending in the direction of the pipe axis so that the center of the image is centered on the connection port 15. The angle detected by the rotation angle sensor 39 at the end of this pipe circumferential alignment is recorded as the angle in the pipe circumferential direction.

[0040] In the next step 112, it is determined whether all connection ports 15 have been detected. If the result is negative, the program returns to step 101 to detect the next connection port 15. If the result is positive, the program proceeds to step 113, where Nmax (the total number of connection ports 15) is calculated from N-1, and the preparation process program ends.

[0041] As described above, in the preparation process, the travel distance L(N) and angle in the circumferential direction of the pipe are recorded for each sequence of connection ports 15, and each time a reinforcing bar 11 is detected, the travel distance LL(M) associated with the sequence of the reinforcing bars 11 can be calculated and recorded.

[0042] <Details of this process> Next, we will explain this process. As shown in Figure 4, the system used to perform this process is the same as the system used for the preparation process. The control and calculations for this process, performed by the control calculation unit 43, will be explained with reference to Figure 5. The characteristic of this control calculation is that each time a reinforcing bar 11 is detected, the travel distance is corrected to match the travel distance associated with the count value (number) of the reinforcing bar 11 recorded in the preparation process, and the position of the video camera 32 when the travel distance matches the travel distance to the connection port 15 recorded in the preparation process is estimated to be the pipe axis position of the connection port 15.

[0043] In step 200, the system is initialized to N=1, M=1, and L=0, similar to step 100 of the preparation process. In step 201, after this initialization, the drive unit 38 is driven, and the vehicle 31 automatically starts moving along the pipe axis of the existing pipe 10 from the pipe end on the manhole 1A side toward the manhole 1B.

[0044] The next steps 202 and 203 are the same as steps 101 and 103 of the preparation process. That is, in step 202, the system waits for a pulse from the rotary encoder 49. When a pulse is received, the system proceeds to step 203, where the calculation L = L + Lp is performed to determine the distance L traveled by the vehicle 31.

[0045] In the next step 204, it is determined whether the travel distance L has reached the travel distance corresponding to the Nth connection port 15. If the determination is negative, the process proceeds to step 205. In step 205, it is determined whether the electromagnetic induction detector 35 has detected the reinforcing bar 11. If the determination is negative, the process returns to step 202. The measured travel distance L increases through the repetition of steps 202 to 205. If a positive result is obtained in step 205, proceed to step 206 and set the temporary storage rebar count value MM as the rebar count value M. This temporary storage rebar count value MM will be explained later.

[0046] In the next step 207, the measured travel distance L is compared with the travel distance LL(M) corresponding to the Mth reinforcing bar 11 measured in the preparation step, and it is determined whether the difference with LL(M) is within a predetermined range α. Specifically, it is determined whether the following conditions are satisfied. LL(M)-α≦L≦LL(M)+α Here, α is less than half the spacing between the reinforcing bars 11. If the spacing between the reinforcing bars 11 is not constant and varies, then α is less than half the minimum spacing.

[0047] If a positive determination is made in step 207, the process proceeds to step 208, where the travel distance L measured when the Mth reinforcing bar 11 is detected is corrected to match the travel distance LL(M) associated with the Mth reinforcing bar 11 recorded in the preparation step. Although there is a difference between the travel distance measured in this step and the travel distance measured in the preparation step, this difference is resolved in step 208 each time a reinforcing bar is detected, so the difference in travel distance between the preparation step and this step does not accumulate. In the next step, 209, the rebar measurement count M is incremented by 1, and the process returns to step 202.

[0048] If the reinforcing bars 11 are successfully detected in the preparation and main processes, it is sufficient to execute steps 208 and 209 when a positive judgment (reinforcing bar detection judgment) is made in step 205. However, in this embodiment, steps 206 and 207 are added as described above, and steps 210 to 212 are also added, in order to address cases where the reinforcing bars 11 are not detected in the preparation or main processes.

[0049] If there is a failure to detect reinforcing bars 11 in the preparation or main process, the travel distance L when the Mth reinforcing bar 11 is detected in the main process will differ significantly from the travel distance LL(M) associated with the Mth reinforcing bar 11 recorded in the preparation process, and this will be judged as negative in step 207.

[0050] If a negative determination is made in step 207, the process proceeds to step 210, where the travel distance L(N) corresponding to the Nth connection port 15 recorded in the preparation process is compared with the travel distance LL(M) associated with the Mth reinforcing bar 11 recorded in the preparation process, and it is determined whether L(N) > LL(M). If a positive determination is made here, that is, if it is determined that the Mth reinforcing bar 11 is before the Nth connection port 15, the process proceeds to step 211, where the number of reinforcing bar measurements M is incremented by 1, and the process returns to step 207. As a result, until a negative determination is made in step 210, the order of the reinforcing bars recorded in the preparation process is increased by one, and the travel distance LL(M) associated with each reinforcing bar number is repeatedly compared with the travel distance L measured in this process in step 207.

[0051] If there are any missed rebar detections in this process, the travel distance when the Mth rebar 11 is detected in this process will be longer than the travel distance LL(M) associated with the Mth rebar 11 in the preparation process. Therefore, in step 211, the number of rebar measurements M is incremented by 1, and the process returns to step 207 to compare it again with the travel distance associated with the incremented number of rebar measurements. In step 207, when the travel distance L in this process is compared with the travel distance LL(M) associated with the number of rebars detected in the preparation process, which has been increased by the number of missed detections, a positive judgment is made and steps 208 and 209 are executed. In other words, the travel distance in this process is corrected to match the travel distance associated with the incremented number of rebar measurements (rebar numbers) in the preparation process, and the number of rebar measurements in this process is adjusted to match the number of rebar measurements incremented in the preparation process.

[0052] If there are any missed rebar detections in the preparation process, the travel distance when the Mth rebar 11 is detected in the main process will be shorter than the travel distance LL(M) associated with the Mth rebar 11 in the preparation process. Therefore, even if the rebar number is incremented in step 211, the travel distance in the main process will deviate further and further from the travel distance associated with the incremented rebar number, and steps 207, 210, and 211 will be repeated. Eventually, the travel distance LL(M) associated with the rebar number in the preparation process will become greater than or equal to the travel distance L(N) to the connection port 15 in the preparation process, so a negative judgment will be made in step 210, and the process will proceed to step 212. In step 212, the number of rebars measured in the main process M will be maintained at the number of temporarily stored rebars measured MM as described above. After executing step 212, the process returns to step 202, and steps 202 to 205 are repeated, waiting for rebar detection while measuring the travel distance.

[0053] If rebar is detected in step 205, the process proceeds through step 206 to step 207. If a negative result is determined here, steps 210 and 212 are executed, and the process returns to step 202. This loop is repeated until a positive result is determined in step 207. If travel in this process continues and the travel distance increases by a distance equivalent to the distance of missed rebar detection in the preparation process, a positive judgment is made in step 207, and steps 208 and 209 are executed. That is, the travel distance L in this process is corrected to match the travel distance LL(M) related to the number of primary stored rebars measured MM in the preparation process. Note that the number of rebars measured in this process is not counted each time a rebar is detected, but is maintained at the number of primary stored rebars measured MM (see step 212), so when a positive judgment is made in step 207 and the travel distance is corrected in step 208, the number of rebars measured in this process matches the number of rebars measured in the preparation process.

[0054] When a positive determination is made in step 204, that is, when the measured travel distance L matches the travel distance L(N) corresponding to the Nth connection port 15 determined in the preparation step, the process proceeds to step 213 to stop travel, then in step 214 the order N of the connection ports 15 is incremented, and finally in step 215 the rotation drive unit 34 is driven to align the optical axis of the video camera 32 with the connection port 15 so that the detected angle of the rotation angle sensor 39 becomes the angle in the circumferential direction of the pipe recorded in the preparation step.

[0055] Step 215 includes a drilling process. This drilling process will be briefly described below. As shown in Figure 4, the mobile drilling device 50 is inserted into the rehabilitation pipe 20 from the manhole 1B side in advance and brought close to the movement detection device 30. The mobile drilling device 50 consists of a traveling vehicle 51 and a drilling unit 53 attached to the traveling vehicle 51 via a rotary drive unit 52. It is controlled based on operations by an operator at a base station 60 located on the ground near the manhole 1B, and moves backward as the movement detection device 30 moves forward.

[0056] As described above, the operator of the base station 60 drives the rotary drive unit 52 and the drilling unit 53 while viewing the video from the video camera 32 of the aligned movement detection device 30, thereby drilling a communication port connected to the connection port 15. As described above, in this process, each time a reinforcing bar 11 is detected, the travel distance is corrected to match the travel distance in the preparation process. This prevents the accumulation of differences between the travel distances measured in the preparation process and the main process, allowing for accurate estimation of the position of the connection port 15 based on the travel distance from the reinforcing bar 11. As a result, mis-drilling can be avoided, and the diameter of the drilling blade in the drilling section 50 can be made relatively large, thus shortening the drilling time.

[0057] Once the drilling operation is complete, the operator sends a drilling completion signal from the operation unit 45 to the control calculation unit 43. Upon receiving the drilling completion signal, the control calculation unit 43 proceeds to step 216, where it determines whether Nmax is N-1 or not, that is, whether the position detection and drilling process has been completed for all connection ports 15. If the determination is negative, it returns to step 201; if the determination is positive, it terminates the program.

[0058] <Second Embodiment> Next, a second embodiment, which is implemented using a system similar to that of the first embodiment, will be described with reference to Figures 6 and 7. n represents the count (order; serial number) of connection ports 15 counted from one end of the pipe on the manhole 1A side of the existing pipe 10. m represents the count (order; serial number) of reinforcing bars 11 counted from one end of the pipe on the manhole 1A side. L is the mileage traveled by the vehicle 31.

[0059] <Details of the preparation process> In the control calculation during the preparation process shown in Figure 6, n=1, m=0, and L=0 are initialized in step 300, then the vehicle starts moving in step 301, the pulse is waited for in step 302, and the travel distance L is calculated in step 302. Since these steps 301 to 303 are the same as the preparation process in the first embodiment, a detailed explanation is omitted (see steps 101 to 103 in Figure 3).

[0060] In the next step, 304, it is determined whether or not reinforcing bars 11 have been detected. If the determination is positive, in step 305 the reinforcing bar count value m is incremented by 1, and then in step 306 the travel distance L is set to 0. In this way, the travel distance L is cleared each time reinforcing bars 11 are detected, so the travel distance is not accumulated.

[0061] After step 306 is performed, or if a negative result is obtained in step 304, the next step 307 determines whether or not the connection port 15 has been detected. If a negative result is obtained here, the process returns to step 302; if a positive result is obtained, the process proceeds to step 308 and the vehicle stops. Steps 307 and 308 are the same as the preparation steps of the first embodiment, so a detailed explanation is omitted (see steps 104 and 108 in Figure 3).

[0062] In the next step 309, we store M(n)=m and L(n)=L. Here, M(n) is the count of reinforcing bars 11 detected by the video camera 32 until the nth connection port 15 is detected. L(n) is the distance traveled by the vehicle 31 after counting M(n) reinforcing bars 11 until the nth connection port 15 is detected. These M(n) and L(n) substantially determine the position of the connection port 15 in the axial direction of the pipe.

[0063] In the next step 310, n is incremented to prepare for locating the next connection port 15. In the next step 311, the video camera 32 is rotated to align with the connection port 15 in the circumferential direction of the pipe, and the angle is recorded. Since this step 311 is the same as the preparation step of the first embodiment, a detailed explanation is omitted (see step 111 in Figure 3).

[0064] In the next step 312, it is determined whether the location of all connection ports 15 has been identified based on the information of the order n of the connection ports 15. If the determination is negative, the program returns to step 301 and repeats steps 302 to 311 to detect the next connection port 15. If the determination is positive, the program terminates.

[0065] As is clear from the control flow in Figure 6, in this embodiment, information on the distance traveled from the end of the existing pipe 10 to the connection port 15 is not obtained. The axial position of the nth connection port 15 is determined by the rebar count value M(n) and the distance traveled L(n) from the rebar in front of the nth connection port 15.

[0066] <Details of this process> In the control and calculation of this process shown in Figure 7, steps 400 to 406 are the same as steps 300 to 306 of the preparation process, so their explanation is omitted. In these steps, the rebar count value m and the distance traveled L from the last detected rebar 11 are determined in order to estimate the position of the nth connection port 15.

[0067] After performing step 406, or if a negative result was made in step 404, step 407 determines whether the rebar count value m has reached the rebar count value M(n) up to the nth connection port 15, which was determined in the preparation step. If a negative result is made here, the process returns to step 402; if a positive result is made, the process proceeds to step 408, where it is determined whether the distance traveled L from the M(n)th rebar 11 has reached the distance traveled L(n) recorded in the preparation step.

[0068] If a negative judgment is made in step 408, the process returns to step 402; if a positive judgment is made, the process proceeds to step 409. A positive judgment in step 408 means that the axial position of the video camera 32 and the connection port 15 coincide. Note that the travel distance L(n) in the preparation process and the travel distance L in this process are not cumulative travel distances, but rather very short travel distances since the detection of the last reinforcing bar 11. Since the difference in travel distance due to the difference in the internal condition of the existing pipe 10 and the rehabilitated pipe 20 is not accumulated, the travel distances can be accurately compared, and consequently, the axial position of the connection port 15 can be accurately estimated.

[0069] In step 409, the vehicle is stopped. In the next step 410, the order n of the connection ports 15 is incremented by 1. In the next step 411, the video camera 32 is positioned so that it matches the angle in the circumferential direction of the pipe recorded in the preparation step, similar to step 215 of the main process in the first embodiment. Step 411 includes a drilling step.

[0070] In the next step 412, it is determined whether the location estimation and drilling of all connection ports 15 in the existing pipe 10 to be rehabilitated have been completed. If the determination is negative, steps 401 to 411 are repeated for the next connection port 15. If the determination is positive, the program is terminated.

[0071] <Other Embodiments> The present invention is not limited to the embodiments described above, and various modifications can be made without departing from its spirit. In the above embodiment, each time the detection and estimation of a connection port is completed, the measurement of the number of reinforcing bars and the distance traveled may be started anew toward the next connection port. If the diameter of the existing pipe is large, the drilling work can be performed by an operator instead of the mobile drilling device shown in Figure 4 during this process. In this case, the operator of the base station 40 may look at the video camera 32 displayed on the display unit 44 and instruct the operator inside the existing pipe 10 to accurately drill the hole so that the drilling position aligns with the center of the video. Alternatively, an illumination light source may be attached to the video camera 32, and this light source may be used to illuminate the inner surface of the rehabilitated pipe 20 to indicate the drilling position (connection port position).

[0072] If the diameter of the existing pipe is large enough for a worker to enter, the video camera installed on the vehicle may be omitted in the preparation process, and the worker may visually determine whether the pipe axis position of a specific part of the vehicle aligns with the pipe axis position of the connection port. Alternatively, in this process, a lighting device to illuminate the connection port position may be installed instead of a video camera.

[0073] The means for measuring the distance traveled may be a rotary encoder that detects the rotation speed of a roller (for example, the roller 37 provided on the electromagnetic induction detector 35 in the above-described embodiment) installed on the vehicle and rolling in contact with the inner surface of the existing pipe 10 or the reconditioned pipe 20, instead of a rotary encoder 49 that measures the length of the cable 46, or a rotation sensor that detects the rotation speed of the vehicle's wheels.

[0074] The electromagnetic induction detection means may use an excitation / detection coil that serves as both the excitation coil and the detection coil of the electromagnetic induction detection means of the above embodiment (i.e., substantially incorporates both). In this case, the excitation circuit and the detection circuit are connected to the excitation / detection coil. The electromagnetic detection means may also be an electromagnetic radar means, which emits electromagnetic waves toward the reinforcing bars of an existing pipe and detects the reinforcing bars by receiving the reflection of electromagnetic waves from the reinforcing bars. The ring-shaped reinforcing bar may be a circular ring-shaped reinforcing bar, or it may be a single turn of a spirally wound reinforcing bar. Existing pipes are not limited to sewer pipes; they may also be water supply pipes, agricultural water pipes, gas pipes, etc. [Industrial applicability]

[0075] This invention can be applied, for example, to the rehabilitation of aging sewer pipes. [Explanation of Symbols]

[0076] 10 Existing pipes 11 Ring-shaped reinforcing bars 15 connection ports 16 Mounting pipe 20 Rehabilitation pipe 31 vehicles 32 video cameras 34 Rotary drive unit 35 Electromagnetic induction type detector (electromagnetic detection means) 38. Drive unit 39. Rotation Angle Sensor 43 Control and calculation unit (calculation unit) 46 Cables 47 Pulley 49. Rotary encoder (means for measuring mileage)

Claims

1. In a method for detecting the position of a connection port from the inside of a rehabilitation pipe, in which a rehabilitation pipe is lined on the inner circumference of an existing reinforced concrete pipe having a connection port for connecting a branch pipe, and the connection port is blocked by the rehabilitation pipe, The process comprises a preparatory step performed prior to lining the rehabilitation pipe, and a main step performed after lining the rehabilitation pipe. In the preparation step, a vehicle equipped with an electromagnetic detection means is driven along the pipe axis of the existing pipe, and the annular reinforcing bars arranged at intervals in the pipe axis direction in the existing pipe are detected by the electromagnetic detection means to obtain a reinforcing bar count value, and the travel distance of the vehicle is measured by a travel distance measuring means, and the information regarding the reinforcing bar count value and the travel distance obtained until the pipe axis position of a specific part of the vehicle coincides with the pipe axis position of the connection port is recorded as information to identify the pipe axis position of the connection port. In the main step, a vehicle equipped with an electromagnetic detection means is driven along the pipe axis of the rehabilitation pipe, the reinforcing bars are detected by the electromagnetic detection means to obtain a reinforcing bar count value, and the travel distance of the vehicle is measured by a travel distance measuring means. The position of the connection port in the pipe axis direction of the connection port is estimated by comparing the information on the reinforcing bar count value and the travel distance obtained in the main step with the information on the reinforcing bar count value and the travel distance recorded in the preparation step.

2. In the preparation step described above, each time a rebar is detected, the travel distance is recorded in association with the rebar count value, and the travel distance measured until the pipe axis position of a specific part of the traveling vehicle coincides with the pipe axis position of the connection port is recorded as the travel distance to the connection port. The method for detecting the position of a connection port of an existing pipe according to claim 1, characterized in that, each time a rebar is detected in the main step, the travel distance associated with the rebar count value in the preparation step that matches the rebar count value in the main step is searched, the travel distance measured in the main step is corrected to match the travel distance in the preparation step that was searched, and the position in the pipe axis direction of a specific part when the travel distance in the main step reaches the travel distance to the connection port recorded in the preparation step is estimated to be the position in the pipe axis direction of the connection port.

3. The above-mentioned process includes a comparison step, which determines whether the difference between the travel distance measured in the above-mentioned process and the searched travel distance is within a predetermined range each time a rebar is detected. If a positive judgment is made in the comparison step, the mileage traveled in this process is corrected to match the mileage found. The method for detecting the connection port position of an existing pipe according to claim 2, characterized in that, when a negative judgment is made in the comparison step, the rebar count values ​​in the preparation step are incremented by 1 and the travel distance associated with each rebar count value is re-searched, the travel distance in the main step is compared with the re-searched travel distance in the comparison step, and when a positive judgment is made in the comparison step, the travel distance measured in the main step is corrected to match the re-searched travel distance, and the rebar count values ​​in the main step are corrected to match the incremented rebar count values.

4. The method for detecting the connection port position of an existing pipe according to claim 3, characterized in that, through repeated negative judgments in the comparison step, the travel distance associated with the rebar count value in the preparation step to be compared becomes greater than or equal to the travel distance to the connection port recorded in the preparation step, the rebar count value in the main step is maintained as a temporarily stored rebar count value, and the rebar count value is not updated when rebar is detected during subsequent travel, and in the comparison step, the travel distance in the main step is compared with the travel distance associated with the rebar count value in the preparation step which is equal to the temporarily stored rebar count value, and when a positive judgment is made in the comparison step, the travel distance in the main step is corrected to match the travel distance in the preparation step, and the rebar count value in the main step is set as the temporarily stored rebar count value.

5. The method for detecting the position of a connection port of an existing pipe according to claim 3 or 4, characterized in that the predetermined range is less than half the spacing between the reinforcing bars.

6. In the preparation step, each time a reinforcing bar is detected by the electromagnetic detection means, the measured travel distance is cleared, and the reinforcing bar count obtained until the pipe axis position of the specific part coincides with the pipe axis position of the connection port, and the travel distance since the reinforcing bar immediately preceding the connection port was detected are recorded as information to identify the position of the connection port. The method for detecting the position of a connection port of an existing pipe according to claim 1, characterized in that, in the above step, each time a reinforcing bar is detected by the electromagnetic detection means, the measured travel distance is cleared, and the position of the specific part in the pipe axis direction when the reinforcing bar count value and the travel distance measured from the time of reinforcing bar detection match the reinforcing bar count value and the travel distance recorded in the preparation step, respectively, is estimated to be the position of the connection port in the pipe axis direction.

7. The method for detecting the position of a connection port of an existing pipe according to claim 1, characterized in that a portion of a signal transmission cable connected to the front of the vehicle is stretched over a pulley, and a rotary encoder for detecting the rotation speed of this pulley is provided as the means for measuring the travel distance.

8. The method for detecting the position of a connection port of an existing pipe according to claim 1, characterized in that, in the preparation step, a video camera is installed on the specific part of the vehicle, and the vehicle is driven so that the pipe axial position of the specific part matches the pipe axial position of the connection port based on the image of the connection port captured by the video camera.

Images