System and method for externally working an annular joint portion of a pipe

Abstract

A system for externally working an annular joint portion of a pipe has a robotic arm (10); a working tool (11), which is carried by the robotic arm (10) and is configured to perform a machining of the annular joint portion (8) of the pipe (1); a sensor assembly (12) configured to detect geometric parameters of the pipe (1); a control unit (13), which is in communication with the sensor assembly (12) and is configured to control the robotic arm (10) and the working tool (11) as a function of the geometric parameters detected by the sensor assembly (12).

Description

[0001] "SYSTEM AND METHOD FOR EXTERNALLY WORKING AN ANNULAR JOINT

[0002] PORTION OF A PIPE"

[0003] Cross-Reference to Related Applications

[0004] This Patent Application claims priority from Italian Patent Application No . 102024000027564 filed on December 5 , 2024 , the entire disclosure of which is incorporated herein by reference .

[0005] Background

[0006] The present invention relates to a system and method for externally working an annular j oint portion of a pipe .

[0007] Prior Art

[0008] In the oil & gas sector, it is commonly known to use pipes formed of pieces of pipe welded to each other in the field for the transport of hydrocarbons . Typically, each piece of pipe has a length of around 12 metres and comprises a hollow metal cylinder, generally made of steel , on the outer surface of which protective coatings with rustproofing, thermal insulation and mechanical protection functions are applied . The sections at the free ends of each piece of pipe have no coating, either internally or externally, and are commonly known as "cutbacks" .

[0009] Generally speaking, the manufacture of a pipe of the type identi fied above is performed directly at the installation site , which can be a marine or land-based installation site , welding together the pieces of pipe so as to form one seamless pipe . In particular, at marine installation sites , the manufacture of such pipes is performed on board pipe- laying ships equipped with tensioning devices that apply a controlled tension on the pipe during the installation phase , by means of rolling friction ( tensioners ) or static friction (mobile clamps ) .

[0010] Once the welding between two pieces of pipe has been performed, it is necessary to restore in the field the protective coating on the zone of the pipe cutback . The performance and application in the field of the protective coating is called " Field Joint Coating" .

[0011] The process of applying the protective coating provides for preparing the surface of the annular j oint portion to a finishing grade compatible with the application of the coating materials . Consequently, a plurality of operations are necessary on each annular j oint portion, performed in the following sequence :

[0012] - perform blasting on the annular j oint portion to remove impurities and oxidation from the surface of the annular j oint portion and give such surface a speci fic level of roughness ;

[0013] - pre-heat the annular j oint portion to a first temperature to facilitate the subsequent steps of application of polymeric materials ;

[0014] - apply a layer of coating in polymeric material directly onto the annular j oint portion; and

[0015] - heat the annular j oint portion to a second temperature higher than the first temperature , in order to obtain the complete cross-linking of the polymeric material applied .

[0016] In particular, the external blasting operations are typically performed by means of a speci fic clamping machine , which is clamped around the annular j oint portion of the pipe , so as to delimit a closed chamber, and is provided with at least one blasting noz zle to dispense an abrasive material at high speed against the outer surface of the annular j oint portion . By way of example , a machine of the type identi fied above is described in document US 5 , 191 , 740 .

[0017] However, the blasting and coating operations performed by means of the clamping machines described above result in lengthy dead times , due to the need to install the clamping machine on the pipe and remove the clamping machine from the pipe production line once the operations are completed .

[0018] Furthermore , the pipe-laying ship on which the blasting and coating operations are performed is generally subj ect to j erking movements which, i f excessive , can result in an unpredictable movement of the pipe , commonly called " lunging" . The term " lunging movement" means a relative movement between the pipe-laying ship and the pipe being installed, provided by the tensioning devices to avoid unacceptable stresses caused by the pipe-laying ship on the pipe itsel f .

[0019] In particular, such lunging movement of the pipe can result in the breakage of cables and / or hoses connected to said clamping machines , and also collision between said clamping machines and the tensioning devices .

[0020] In addition, each clamping machine of the type identi fied here above can be used solely on pipes having a speci fic outer diameter . The result is that , when the outer diameter of the pipe varies , it is necessary to provide a clamping machine with di f ferent dimensional characteristics .

[0021] These problems are made worse by the fact that the particular mechanics of the clamping machines described here above require regular maintenance interventions .

[0022] Object of the Invention

[0023] An obj ect of the present invention is to obtain a machine for externally working an annular j oint portion of a pipe that is capable of mitigating the drawbacks of the prior art indicated here .

[0024] In accordance with the present invention, a system for externally working an annular j oint portion of a pipe extending along a longitudinal axis is provided, the system comprising :

[0025] - at least one robotic arm;

[0026] - a working tool , which is carried by the robotic arm and is configured to perform a machining of the annular j oint portion of the pipe ;

[0027] - a sensor assembly configured to detect geometric parameters of the pipe ; and

[0028] - a control unit , which is in communication with the sensor assembly and is configured to control the robotic arm and the working tool as a function of the geometric parameters detected by the sensor assembly .

[0029] Thanks to the invention, it is possible to externally work annular j oint portions with a reduction in the process cycle time .

[0030] In particular, thanks to the present invention, it is possible to reduce the working dead times , due , for example , to the setting and / or movement of the clamping machines , and simultaneously to improve the quality of the working, given that such working is performed considering the actual characteristics , rather than the nominal ones , of the annular j oint portion .

[0031] The system obtained in accordance with the present invention is capable of controlling, extremely flexibly, the spatial position of the working tool , so as to compensate for any misalignments of the pipe relative to a reference position and to allow working of pipes with an outer diameter of di f ferent dimensions .

[0032] Similarly, it is possible to work on the pipe safely even in the presence of lunging movements of the pipe , thus improving the operating limits of such working .

[0033] Furthermore , thanks to the system of the present invention, it is possible to reduce the overall dimensions , costs and safety risks associated with the use of equipment for performing working on the annular j oint portion of the pipe .

[0034] In particular, the control unit is configured to calculate a position of the longitudinal axis of the pipe , preferably at the annular j oint portion, as a function of said detected geometric parameters , to calculate an optimal working traj ectory around the pipe for the working tool as a function of the calculated position of the longitudinal axis , and to control the robotic arm so that the working tool follows said calculated optimal working traj ectory .

[0035] In other words , the control unit is configured to calculate the spatial position of the longitudinal axis of the pipe relative to the reference system of the robotic arm integral with the pipe-laying ship and calculated on the basis of the detections made by the sensor assembly . The purpose of such calculation of the spatial position of the longitudinal axis of the pipe is immediate execution of the optimal working traj ectory around the pipe for the working tool .

[0036] In this manner, it is possible to further reduce the dead times linked to setting of the initial position of the tool , which, vice versa, must be performed by the clamping machines to configure the initial working point as a function of the speci fic geometry of the annular j oint portion to be worked .

[0037] In particular, the control unit is configured to process a three-dimensional geometry of the annular j oint portion as a function of said geometric parameters detected by the sensor assembly, to calculate an optimal working traj ectory for the tool around the pipe as a function of said processed three-dimensional geometry, and to control the robotic arm so that the working tool follows said calculated optimal working traj ectory .

[0038] In this manner, it is possible to determine an optimal traj ectory based on the speci fic dimensional characteristics of each annular j oint portion . In particular, the system comprises a support frame , which is carried by the robotic arm and supports the working tool .

[0039] In greater detail , the system comprises a plurality of working tools coupled to the support frame .

[0040] In this manner, it is possible to perform a plurality of workings simultaneously along di f ferent circumferential sections of the annular j oint portion .

[0041] In particular, the support frame comprises a central body and a pair of supports , each of which is coupled to the central body and supports at least one working tool .

[0042] In this manner, it is possible to angularly distance the working tools along the circumferential profile of the annular j oint portion, in order to perform workings simultaneously along di f ferent sections of the annular j oint portion .

[0043] In particular, the support frame is coupled rotatably to an end portion of the robotic arm .

[0044] In this manner, it is possible to precisely adj ust the orientation of the working tools relative to the annular j oint portion .

[0045] In particular, the sensor assembly is carried by the robotic arm . In this manner, it is possible to detect the geometric parameters of the pipe directly at the annular j oint portion to be worked .

[0046] In particular, the working tool comprises a blasting unit configured to perform blasting operations on the annular j oint portion and / or a coating unit configured to dispense a coating material on the annular j oint portion and / or a heating unit configured to heat the annular j oint portion and / or a welding unit configured to perform a weld on the annular j oint portion and / or a surface preparation unit configured to process areas of the pipe adj acent to the annular j oint portion and / or a non-destructive inspection probe .

[0047] In practice , thanks to the system of the present invention, it is possible to perform a broad variety of di f ferent workings on the annular j oint portion .

[0048] In particular, the system comprises a slidable slide on which the robotic arm is mounted .

[0049] In this manner, it is possible to adj ust the position of the robotic arm along the longitudinal axis relative to the annular j oint portion to be worked, compensating for any undesired deviations .

[0050] A further obj ect of the present invention is to obtain a method for externally working an annular j oint portion of a pipe that mitigates the drawbacks of the prior art . In accordance with the present invention, a method for externally working an annular j oint portion of a pipe extending along a longitudinal axis is provided, the method comprising the steps of :

[0051] - detecting geometrical parameters of the pipe ;

[0052] - calculating a position of the longitudinal axis of the pipe , preferably at the annular j oint portion, as a function of said detected geometrical parameters ;

[0053] - calculating an optimal working traj ectory around the pipe for a working tool as a function of the calculated position of the longitudinal axis ;

[0054] - controlling a robotic arm that carries the working tool so that the working tool follows said calculated optimal working traj ectory; and

[0055] - performing a machining of the annular j oint portion of the pipe using the working tool .

[0056] Thanks to the present method, it is possible to externally work annular j oint portions of the pipe flexibly, rapidly and economically, simultaneously guaranteeing a suf ficient quality of the working in any operating condition, including in the presence of maj or geometric-dimensional discrepancies between one annular j oint portion and another .

[0057] Brief Description of the Drawings

[0058] Further characteristics and advantages of the present invention will become apparent from the following description of preferred embodiments thereof , with reference to the appended drawings , in which :

[0059] - Figure 1 is a side view, with parts in cross-section and parts removed for clarity, of a pipe that is partially coated externally;

[0060] - Figure 2 is a perspective view, with parts removed for clarity, of a system for externally working an annular j oint portion of the pipe of Figure 1 , performed in accordance with the present invention;

[0061] - Figure 3 is a side view, with parts removed for clarity, of a detail of the system of Figure 2 ; and

[0062] - Figure 4 is a perspective view, with parts removed for clarity, of the detail of Figure 3 .

[0063] Detailed Description of the Drawings

[0064] With reference to Figure 1 , the number 1 is used to indicate , in its entirety, a pipe to be externally worked, extending along a longitudinal axis Al .

[0065] In the case described and illustrated here , the pipe 1 comprises two pieces of pipe 2 aligned along the longitudinal axis Al . Each piece of pipe 2 comprises a metal cylinder 3 and a coating 4 , preferably rustproof , in polymeric material , which is arranged in contact with the metal cylinder 3 and has the function of protecting the metal cylinder 3 from corrosion .

[0066] By way of example , the coating 4 can be made of a polymeric material comprising a base component and a hardening component , such as , for example , a thermosetting epoxy resin or a two-component powder .

[0067] Each piece of pipe 2 has two opposite free ends 5 ( only one of which is shown in Figure 1 ) without coating 4 , which has a chamfer 6 at each free end 5 . Two successive pieces of pipe 2 aligned along the longitudinal axis Al are arranged with the free ends 5 facing and are welded so as to obtain an annular weld bead 7 between the two pieces of pipe 2 . The two welded pieces of pipes 2 define an annular j oint portion 8 , which extends along the longitudinal axis Al between the two chamfers 6 of the coating 4 and comprises the annular weld bead 7 .

[0068] The pipe 1 is formed by means of the j oining of pieces of pipe 2 . With reference to the present description, the term pipe 1 also means the pipe during the construction phase , which can be formed, for example , of only two pieces of pipe 2 j oined to each other .

[0069] With reference to Figure 2 , the reference number 9 indicates , in its entirety, a system for externally working the annular j oint portion 8 of the pipe 1 .

[0070] The system 9 can be used on a fabrication line of the pipe 1 on board a pipe-laying ship, in particular, for externally working an annular j oint portion 8 of a multiple piece of pipe 2 , without thus limiting the broad range of applications of the present invention . It is understood that the system 9 can also be used to work any annular j oint portion 8 of a pipe 1 , independently of the installation site or the construction phase .

[0071] In accordance with the present invention, the system comprises a robotic arm 10 ; a working tool 11 , which is carried by the robotic arm 10 and is configured to perform a machining of the annular j oint portion 8 of the pipe 1 ; a sensor assembly 12 configured to detect geometric parameters of the pipe 1 ; a control unit 13 , which is in communication with the sensor assembly 12 and is configured to control the robotic arm 10 and the working tool 11 as a function of the geometric parameters detected by the sensor assembly 12 .

[0072] In particular, said geometric parameters are indicative of a surface conformation of the pipe 1 , preferably at the annular j oint portion 8 , and / or of a circumferential profile of the pipe 1 and / or of a spatial position of the pipe 1 and / or of a distance of the annular j oint portion 8 from a reference point .

[0073] In accordance with the present invention, the control unit 13 is configured to calculate a position of the longitudinal axis Al of the pipe 1 , preferably at the annular j oint portion 8 , as a function of said detected geometric parameters , to calculate an optimal working traj ectory around the pipe 1 for the working tool 11 as a function of the calculated position of the longitudinal axis Al , and to control the robotic arm 10 so that the working tool 11 follows said calculated optimal working traj ectory .

[0074] In particular, the control unit 13 is configured to process a three-dimensional geometry of the annular j oint portion 8 as a function of said geometric parameters detected by the sensor assembly 12 and to calculate an optimal working traj ectory around the pipe 1 as a function of said processed three-dimensional geometry . In accordance with one embodiment , the control unit 13 is configured to process said three-dimensional geometry in the form of a digital model .

[0075] In accordance with one embodiment , the sensor assembly 12 comprises a laser profilometer and / or a three-dimensional stereoscopic sensor and / or a time-of- f light sensor and / or a laser triangulation sensor and / or a lidar sensor and / or a holographic sensor and / or an odometer .

[0076] In the non-limiting case of the present invention described and illustrated here , the sensor assembly 12 is carried by the robotic arm 10 .

[0077] In accordance with an alternative embodiment of the present invention, not shown in the appended drawings , the sensor assembly 12 is arranged at a fixed position of a pipe 1 fabrication line , preferably at the beginning and / or at the end of the pipe fabrication line , to detect geometric parameters of the pipe 1 at the inlet and / or at the outlet of the pipe 1 from the pipe fabrication line .

[0078] In particular, the system 9 comprises a slidable slide 14 on which the robotic arm 10 is mounted . In the non-limiting case of the present invention described and illustrated here , the slide 14 is slidable along a direction substantially parallel to the longitudinal axis Al . It is understood that , in accordance with a variant of the present invention not shown in the appended drawings , the slide 14 is slidable both along a direction substantially parallel to the longitudinal axis Al and along a direction substantially perpendicular to the longitudinal axis Al . In accordance with a further variant of the present invention, not shown in the appended drawings , the sensor assembly 12 is coupled to the slide 14 .

[0079] Furthermore , the system 9 comprises a base 15 provided with a linear guide 16 to which the slide 14 is slidably coupled, and an actuator, not shown in the appended drawings , which is configured to control a sliding of the slide 14 along the linear guide 16 .

[0080] In accordance with an embodiment , the robotic arm 10 is integrally coupled with a pipe-laying ship, not shown in the appended drawings .

[0081] In particular, the robotic arm 10 comprises a base body 17 integral with the slide 14 ; a rotating body 18 coupled to the base body 17 rotatably around an axis substantially perpendicular to the longitudinal axis Al ; an arm 19 coupled rotatably to the rotating body 18 ; an arm 20 coupled rotatably to the arm 19 ; a wrist 21 , which is rotatably coupled to the arm 20 and carries the working tool 11 ; and a plurality of actuators , not shown in the appended drawings , which are configured to move the rotating body 18 , the arms 19 and 20 , and the wrist 21 .

[0082] In greater detail , the system 9 comprises a support frame 22 , which is carried by the robotic arm 10 and supports the working tool 11 . In the case described and illustrated here , the support frame 22 is coupled rotatably to an end portion of the robotic arm 10 and, in particular, is mechanically connected to the wrist 21 of the robotic arm 10 . In the non-limiting case of the present invention described and illustrated here , the system 9 comprises a plurality of working tools 11 coupled to the support frame 22 .

[0083] With reference to Figures 3 and 4 , the support frame 22 comprises a central body 23 and a pair of supports 24 , each of which is coupled to the central body 23 and supports the respective working tool 11 .

[0084] In the case described and illustrated here , each support 24 is integrally coupled with the central body 23 and, proj ects from the central body 23 so as to angularly distance the working tools 11 along the circumferential profile of the annular j oint portion 8 .

[0085] In greater detail , the support frame 22 comprises a face 25 and a face 26 , which extend along respective planes substantially perpendicular to each other . Each support 24 proj ects from the respective face 25 , 26 , so as to delimit an angle of around 90 ° between them .

[0086] In particular, the sensor assembly 12 is coupled to the support frame 22 , preferably integrally therewith . In greater detail , the support frame 22 comprises an arm 27 , which is integrally coupled with the central body 23 and supports the sensor assembly 12 .

[0087] In the non-limiting case of the present invention described and illustrated here , each working tool 11 comprises a blasting unit 28 configured to perform blasting operations on the annular j oint portion 8 .

[0088] In particular, each blasting unit 28 is configured to dispense an abrasive material at high speed against the outer surface of the annular j oint portion 8 .

[0089] In greater detail , each blasting unit 28 comprises an end mani fold 29 , which is preferably deformable and is shaped to delimit , together with the annular j oint portion 8 , a blasting chamber that is closed when the end mani fold 29 is in contact with the annular j oint portion 8 .

[0090] Furthermore , the blasting unit 28 comprises a feed conduit 30 , which is configured to feed a mixture of pressurised air and abrasive material into the closed chamber, and a suction conduit 31 , which is configured to suck the abrasive material from the closed chamber .

[0091] In accordance with alternative embodiments , not shown in the appended drawings , at least one of the working tools 11 comprises a coating unit configured to dispense a coating material on the annular j oint portion 8 and / or a heating unit configured to heat the annular j oint portion 8 and / or a welding unit configured to perform a weld on the annular j oint portion 8 and / or a surface preparation unit configured to process areas of the pipe 1 adj acent to the annular j oint portion 8 and / or a non-destructive inspection probe .

[0092] With reference to Figure 4 , the system 9 comprises four working tools 11 . In accordance with such a configuration, the support frame 22 comprises four supports 24 , each of which supports the respective working tool 11 .

[0093] In particular, two supports 24 proj ect from the face 25 parallel to each other and the further two supports 24 proj ect parallel to each other from the face 26 .

[0094] In use and with reference to Figure 1 , two successive pieces of pipe 2 are aligned along the longitudinal axis Al with the free ends 5 facing and are welded so as to obtain an annular weld bead 7 between two pieces of pipe 2 , forming the pipe 1 .

[0095] With reference to Figure 2 , the robotic arm 10 moves the sensor assembly 12 at the annular j oint portion 8 and the sensor assembly 12 detects the geometric parameters of the pipe 1 .

[0096] The control unit 13 receives said geometric parameters detected by the sensor assembly 12 and calculates a position of the longitudinal axis Al of the pipe 1 , preferably at the annular j oint portion 8 , as a function of said received geometrical parameters .

[0097] In addition or as an alternative , the control unit 13 processes a three-dimensional geometry in the form of a digital model of the annular j oint portion 8 as a function of said geometrical parameters received .

[0098] At this point , the control unit 13 calculates an optimal working traj ectory around the pipe 1 for the working tool 11 , as a function of said calculated position of the longitudinal axis Al and / or as a function of said processed three-dimensional geometry .

[0099] Once the optimal working traj ectory has been calculated, the control unit 13 controls the actuators of the robotic arm 10 so that the working tool 11 follows said calculated optimal working traj ectory .

[0100] Simultaneously, with reference to Figure 3 , the blasting unit 28 performs blasting operations on the annular j oint portion 8 , dispensing abrasive material at high speed against the outer surface of the annular j oint portion 8 .

[0101] It is clear that variants can be made to the present invention without thus deviating from the scope of protection of the appended claims .

[0102] In particular, in accordance with an embodiment not shown in the appended drawings , the system 9 can comprise two robotic arms 10 , which carry respective working tools 11 and are used to perform machining in a coordinated manner on the pipe 1 . In accordance with such a configuration, the robotic arms 10 are arranged on opposite sides of the pipe 1 and are used to perform di f ferent workings on the pipe 1 . By way of example , while one of the two robotic arms 10 performs blasting operations on the annular j oint portion 8 , the other of the two robotic arms 10 performs non-destructive inspections on the pipe 1 .

Claims

CLAIMS1. A system for externally working an annular joint portion of a pipe extending along a longitudinal axis, the system(9) comprising:- at least one robotic arm (10) ;- a working tool (11) , which is carried by the robotic arm(10) and is configured to perform a machining of the annular joint portion (8) of the pipe (1) ;- a sensor assembly (12) configured to detect geometric parameters of the pipe (1) ; and- a control unit (13) , which is in communication with the sensor assembly (12) and is configured to control the robotic arm (10) and the working tool (11) as a function of the geometric parameters detected by the sensor assembly (12) .

2. The system as claimed in Claim 1, wherein said geometric parameters are indicative of a surface conformation of the pipe (1) , preferably at the annular joint portion (8) , and / or of a circumferential profile of the pipe (1) and / or of a spatial position of the pipe (1) and / or of a distance of the annular joint portion (8) from a reference point.

3. The system as claimed in Claim 1 or 2, wherein the control unit (13) is configured to calculate a position of the longitudinal axis (Al) of the pipe (1) , preferably at the annular joint portion (8) , as a function of said detected geometric parameters, to calculate an optimal working trajectory around the pipe (1) for the working tool (11) as a function of the calculated position of the longitudinal axis (Al) , and to control the robotic arm (10) so that theworking tool (11) follows said calculated optimal working tra j ectory .

4. The system as claimed in any one of the foregoing Claims, wherein the control unit (13) is configured to process a three-dimensional geometry of the annular joint portion (8) as a function of said geometric parameters detected by the sensor assembly (12) , to calculate an optimal working trajectory for the working tool (11) around the pipe (1) as a function of said processed three-dimensional geometry, and to control the robotic arm (10) so that the working tool (11) follows said calculated optimal working tra j ectory .

5. The system as claimed in any one of the foregoing Claims, wherein the sensor assembly (12) comprises a laser profilometer and / or a three-dimensional stereoscopic sensor and / or a time-of-f light sensor and / or a laser triangulation sensor and / or a lidar sensor and / or a holographic sensor and / or an odometer.

6. The system as claimed in any one of the foregoing Claims, and comprising a support frame (22) , which is carried by the robotic arm (10) and supports the working tool (11) .

7. The system as claimed in Claim 6, and comprising a plurality of working tools (11) coupled to the support frame (22) .

8. The system as claimed in Claim 7, wherein the support frame (22) comprises a central body (23) and a pair ofsupports (24) , each of which is coupled to the central body(23) and supports at least one working tool (11) .

9. The system as claimed in any one of the foregoing Claims, wherein the working tool (11) comprises a blasting unit (28) configured to perform blasting operations on the annular joint portion (8) and / or a coating unit configured to dispense a coating material on the annular joint portion (8) and / or a heating unit configured to heat the annular joint portion (8) and / or a welding unit configured to perform a weld on the annular joint portion (8) and / or a surface preparation unit configured to process areas of the pipe (1) adjacent to the annular joint portion (8) and / or a nondestructive inspection probe.

10. The system as claimed in any one of the foregoing Claims, and comprising a slidable slide (14) on which the robotic arm (10) is mounted.The system as claimed in Claim 10, wherein the sensor assembly (12) is coupled to the slide (14) .

12. The system as claimed in any one of Claims 1 to 10, wherein the sensor assembly (12) is carried by the robotic arm (10) .

13. The system as claimed in any one of Claims 1 to 10, wherein the sensor assembly (12) is arranged at a fixed position of a pipe fabrication line, preferably at the beginning and / or at the end of the pipe fabrication line, to detect geometric parameters of the pipe (1) at the inletand / or at the outlet of the pipe (1) from the pipe fabrication line.

14. The system as claimed in any one of the foregoing Claims, wherein the system (9) is configured to be arranged on board a pipe-laying vessel.

15. A method for externally working an annular joint portion of a pipe extending along a longitudinal axis, the method comprising the steps of:- detecting geometrical parameters of the pipe (1) ;- calculating a position of the longitudinal axis (Al) of the pipe (1) , preferably at the annular joint portion (8) , as a function of said detected geometrical parameters;- calculating an optimal working trajectory around the pipe(1) for a working tool (11) as a function of the calculated position of the longitudinal axis (Al) ;- controlling a robotic arm (10) that carries the working tool (11) so that the working tool (11) follows said calculated optimal working trajectory; and- performing a machining of the annular joint portion (8) of the pipe (1) using the working tool (11) .

16. The method as claimed in Claim 15, and comprising the steps of:- processing a three-dimensional geometry of the annular joint portion (8) as a function of said detected geometric parameters; and- calculating the optimal working trajectory around the pipe (1) as a function of said processed three-dimensional geometry .

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