GB2531706A

GB2531706A - Apparatus and method

Info

Publication number: GB2531706A
Application number: GB1418538.3A
Authority: GB
Inventors: John Langdale Simon; James Little Wesley
Original assignee: NAT GRID GAS PLC; National Grid Gas PLC
Current assignee: National Grid Gas PLC
Priority date: 2014-10-19
Filing date: 2014-10-19
Publication date: 2016-05-04
Also published as: GB201706986D0; GB2545624A; GB201418538D0; GB2545624B; WO2016062661A1

Abstract

A robot drive assembly 110 for moving a robot along a substantially cylindrical pipeline within the pipeline comprises first 111 and second body portions, the first body portion 111 being arranged to be rotated about a longitudinal axis of the assembly relative to the second body portion by drive means, wherein the first body portion 111 has at least one drive roller 111R coupled thereto, the robot being configured wherein rotation of the first body portion 111 relative to the pipeline and second body portion about a longitudinal axis of the first body portion causes the at least one drive roller 111R to rotate in contact with an inner wall of the pipeline about a roller axis oriented such that a resultant force acts on the first body portion in a direction to cause simultaneous rotation and translation of the first body portion with respect to the pipeline. Two such drive assemblies, 111, 111 may be used together, wherein by driving the two assemblies in opposite directions the assembly may be locked in place in the pipeline and the second body portions rotated to change their orientations in the pipeline.

Description

APPARATUS AND METHOD

TECHNICAL FIELD

The present invention relates to pipelines and in particular but not exclusively apparatus for use in the maintenance or installation of pipelines.

BACKGROUND

Maintenance, upgrading and replacement of ageing utilities pipeline infrastructures are major issues facing utilities companies such as water and gas utilities companies. Pipeline networks typically include main supply pipelines (also referred to as the 'mains' supply) and consumer service connection pipelines. The consumer service connection pipelines are connected to the main supply pipelines, typically by means of a T-connection, to deliver a supply of fluid such as water or gas to a consumer's premises from the main supply pipeline.

Utilities supply pipelines are typically located underground, presenting substantial access issues when maintenance, upgrading or replacement is required.

Ageing pipelines are vulnerable to failure and leakage of fluid from pipelines is a known hazard particularly in the case of gas leakage.

One solution to reducing the cost of replacement of pipelines is to install replacement pipeline within pre-existing pipeline, including the main pipeline and consumer service connection pipeline, leaving the pre-existing main pipeline and pre-existing consumer service connection pipeline in place. The replacement main pipeline has an external diameter that is smaller than the internal diameter of the pre-existing main pipeline, allowing it to fit within the pre-existing main pipeline infrastructure. Similarly, the replacement consumer service connection pipeline has a diameter that is smaller than the pre-existing consumer service connection pipeline. The replacement main pipeline may be referred to as a 'main pipeline liner' or 'mains liner' because it effectively lines the pre-existing main pipeline. Similarly the replacement consumer service connection pipeline may be referred to as a 'service connection liner' since it effectively lines the pre-existing consumer service connection pipeline. The consumer service connection pipeline may be of the Serviflex (RTM) type, being a twin wall corrugated flexible polyethylene liner pipe supplied by Radius Systems Ltd, South Normanton, Alfreton, Derbyshire, UK.

In known methods of replacement pipeline installation, the replacement pipeline is installed within the pre-existing pipeline by pulling the replacement pipeline through the pre-existing pipeline. Connection of the replacement consumer service connection pipeline to the replacement main pipeline is made by excavating ground above the location at which the pre-existing service connection pipeline connects to the pre-existing main pipeline. Installer personnel may then remove a portion of the pre-existing main pipeline and pre-existing service connection pipeline in order to expose the replacement pipelines that have been installed therein. A T-connector is then installed on the replacement main pipeline and the replacement service connection pipeline coupled to the replacement main pipeline via the T-connector. The T-connector is typically attached to the main pipeline by forming an electrofusion bond between the T-connector and the main pipeline in a known manner.

It is an aim of the present invention to address disadvantages associated with the prior art.

SUMMARY OF THE INVENTION

Embodiments of the invention may be understood with reference to the appended claims.

Aspects of the present invention provide an apparatus, a robot, a system and a method.

In one aspect of the invention for which protection is sought there is provided a robot drive assembly for moving a robot along a substantially cylindrical pipeline within the pipeline, the assembly comprising first and second body portions, the first body portion being arranged to be rotated about a longitudinal axis of the assembly relative to the second body portion by drive means, wherein the first body portion has at least one drive roller coupled thereto, the robot being configured wherein rotation of the first body portion relative to the pipeline and second body portion about a longitudinal axis of the first body portion causes the at least one drive roller to rotate in contact with an inner wall of the pipeline about a roller axis oriented such that a resultant force acts on the first body portion in a direction to cause simultaneous rotation and translation of the first body portion with respect to the pipeline.

Some embodiments of the invention may be configured for operation in pipelines having a diameter of lm or less, optionally in the range from 10mm to 1m. Some embodiments may be configured for operation in pipelines having a diameter in the range from 50mm to 200mm, optionally from 50mm to 100mm, optionally in the range from 75mm to 90 mm.

The assembly may comprise means for resisting rotation of the second body portion relative to the pipeline about the longitudinal axis of the assembly.

This feature may be useful in assisting propulsion of the assembly along a pipeline.

Optionally, the means for resisting rotation of the second body portion comprises at least one auxiliary roller constrained to rotate about an axis normal to the longitudinal axis of the assembly.

Thus the auxiliary roller may be oriented for movement of the assembly parallel to a longitudinal axis of the pipeline.

Optionally, the at least one drive roller is movably coupled to the first body portion to permit movement of the drive roller towards and away from the first body portion.

The at least one drive roller may be movably coupled to the first body portion by means of a support arm.

Optionally, the at least one drive roller is resiliently coupled to the first body portion by resilient coupling means, the resilient coupling means being configured to urge the at least one drive roller away from the body portion and against an inner wall of the pipeline.

In embodiments in which the at least one drive roller is supported by a support arm, the support arm may be spring-loaded such that the support-arm tends to be urged resiliently away from the first body portion. Movement of the support arm towards the first body portion, for example when negotiating a bend or encountering a change in gradient, may be opposed but accommodated by the spring-loading, ensuring that the drive roller remains in contact with a sidewall of the pipeline substantially at all times.

Optionally, the at least one drive roller is constrained to rotate about an axis having a first helical pitch angle with respect to the longitudinal axis of the assembly.

By helical pitch angle is meant an angle between the longitudinal axis of the assembly and the axis of rotation of the at least one drive roller. It is to be understood that. in the case the roller is a wheel, this angle is equivalent to the angle between the wheel and a plane normal to the longitudinal axis, and/or equivalent to an angle between the wheel and a circumferential direction.

The assembly may comprise actuator means configured to move the at least one roller towards and away from the first body portion between a retracted position and a deployed position, the retracted position being located radially inwardly of the deployed position. The actuator may be referred to as a wall press actuator since the actuator causes the at least one roller to be pressed against an inner wall of the pipeline.

Thus it is to be understood that the actuator means may be configured to cause the at least one roller to be moved radially away from and towards the first body portion, for example between a retracted or collapsed position in which the at least one roller is relatively close to the first body portion, optionally at least partially enclosed by the first body portion, and a deployed or extended position in which the at least one roller is moved to a position radially away from the first body portion.

This feature may be useful when introducing the assembly into a pipeline. Alternatively or in addition this feature may be useful when operating the assembly in pipelines of different respective diameters, allowing the at least one roller to be moved conveniently from the retracted position to a deployed condition a suitable radial distance from the longitudinal axis of the assembly to contact the wall of the pipeline.

The assembly may comprise a plurality of drive rollers provided at angularly spaced locations about the longitudinal axis of the first body portion.

In one aspect of the invention for which protection is sought there is provided apparatus comprising first and second robot drive assemblies according to another aspect, the apparatus being operable to cause the at least one drive roller of the second drive assembly to rotate in contact with the inner wall of the pipeline about an axis oriented such that a resultant force acts on the first body portion of the second drive assembly in a direction to cause simultaneous rotation and translation of the first body portion of the second drive assembly with respect to the pipeline, the direction of translation being opposite that of the first body portion of the first drive assembly.

Thus it is to be understood that, in some embodiments, the first and second robot drive assemblies may be operated such that the force generated by the first drive assembly to cause translation of the assembly along a pipeline in one direction is opposed by a force generated by the second drive assembly to cause translation of the assembly along the pipeline in the opposite direction. If the forces are substantially equal the apparatus may be configured to have no net translation along the pipeline, but remain substantially stationary with respect to longitudinal motion. It is to be understood that, if the forces tending to cause rotation about the longitudinal axis are not balanced in opposite directions, a net rotation of one or more portions of the apparatus, optionally the whole of the apparatus, may occur, with substantially no net translation. This feature may be useful in causing controlled rotation of the second body portions of the first and second drive assemblies, when required.

Optionally, the at least one drive roller of the first drive assembly and the at least one drive roller of the second drive assembly are constrained to rotate about axes having helical pitch angles of opposite sense.

Thus the at least one drive roller of respective drive assemblies may be configured to act to cause translation of the apparatus in opposite directions if the drive assemblies are rotated in the same direction.

Optionally, the at least one drive roller of the first drive assembly and the at least one drive roller of the second drive assembly are constrained to rotate about axes having equal and opposite helical pitch angles.

This feature has the advantage that, if the first and second drive assemblies have (say) equal numbers of similar rollers, rotation of the first body portions with respect to the second body portions in the same rotational direction with respect to the longitudinal axis may result in substantially no net translation of the apparatus along the longitudinal axis due to cancellation of opposing longitudinal forces generated by the respective first body portions.

The apparatus may be operable to prevent relative rotation of the first and second drive assemblies.

The apparatus may comprise locking means for locking the first and second drive assemblies to prevent relative rotation of the first and second assemblies.

The locking means may be any suitable means such as a clutch device, optionally a dog clutch or interference clutch device.

In a further aspect of the invention for which protection is sought there is provided a pipeline robot comprising a drive assembly according to another aspect.

The pipeline robot may comprise a drive assembly coupled to at least one module and configured to cause translation of the drive assembly and module along a pipeline, the drive assembly being coupled to the at least one module by means of a flexible joint portion allowing pivoting of the module with respect to the drive portion about an axis substantially normal to a longitudinal axis of the assembly.

Optionally, the drive assembly is coupled to the at least one module by means of a flexible joint portion allowing pivoting of the module with respect to the drive portion about each of a pair of orthogonal axes substantially normal to a longitudinal axis of the assembly.

The flexible joint portion may be configured to allow independent pivoting of the module about each of the pair of orthogonal axes.

Optionally, the flexible joint portion is configured to prevent axial rotation of the module about a longitudinal axis of the assembly relative to the second body portion of the assembly.

This feature has the advantage that axial rotation of the second body portion with respect to a pipeline may be employed to cause axial rotation of the module. This may be useful in positioning the module at a required angular orientation within the pipeline, for example in order correctly to position a tool or sensor carried by the module such as a drill tool, a tool for installing a fitting, a camera or any other suitable tool or sensor.

In an aspect of the invention for which protection is sought there is provided a method of moving a robot along a substantially cylindrical pipeline within the pipeline, the method comprising providing an assembly comprising first and second body portions, the first body portion being arranged to be rotated about a longitudinal axis of the assembly relative to the second body portion by drive means, wherein the first body portion has at least one drive roller coupled thereto, the method comprising rotating the first body portion relative to the pipeline and second body portion about a longitudinal axis of the first body portion thereby to cause the at least one drive roller to rotate in contact with an inner wall of the pipeline about a roller axis oriented whereby a resultant force acts on the first body portion in a direction to cause simultaneous rotation and translation of the first body portion with respect to the pipeline.

Within the scope of this application it is envisaged that the various aspects, embodiments, examples and alternatives, and in particular the individual features thereof, set out in the preceding paragraphs, in the claims and/or in the following description and drawings, may be taken independently or in any combination. For example features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible.

For the avoidance of doubt, it is to be understood that features described with respect to one aspect of the invention may be included within any other aspect of the invention, alone or in appropriate combination with one or more other features.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying figures in which: FIGURE 1 is a cross-sectional view of a typical operating environment of a pipeline robot according to an embodiment of the present invention; FIGURE 2 shows: (a) to (c), a portion of a spiral drive assembly according to an embodiment of the invention in front (upper image) and side (lower image) views with the assembly in (a) a retracted condition, (b) a semi-deployed condition and (c) a deployed condition; (d) an enlarged side view of a portion of the spiral drive assembly in the deployed condition; and (e) a front view of a first body portion of the assembly illustrating a mechanism for relative rotation of the first and a second body portion of the assembly; FIGURE 3 shows (a) a robot having a spiral drive assembly according to an embodiment of the present invention, (b) a 3D view of a roller support member, (c) a 3D view of a pair of roller support members coupled together and (d) a front view of a pair of roller support members coupled together; FIGURE 4 is a 3D view of a pair of spiral drive assemblies coupled together to form a composite spiral drive assembly; FIGURE 5 is a side view of the composite spiral drive assembly of FIG. 4; FIGURE 6 is a 3D view of the composite assembly shown in FIG. 4 illustrating the directions of rotation of respective assemblies in order to cause translation of the composite assembly; and FIGURE 7 is a 3D view of the composite assembly shown in FIG. 4 illustrating the directions of rotation of respective assemblies in order to cause rotation and not translation of portions of the composite assembly.

DETAILED DESCRIPTION

FIG. 1 shows a typical operational environment of a pipeline robot 100 according to an embodiment of the present invention. It can be seen from FIG. 2 that, in the scenario illustrated, the robot 100 has been introduced into a newly installed main pipeline 101 that is located within pre-existing main pipeline 101E, via an underground inspection well 101A. It is to be understood that the free end 101F of the main pipeline 101 that is exposed to the well 101A may be coupled to the free end 101F2 of a second length of newly installed main pipeline 101 that also terminates in the well 101A once service connection pipelines have been connected to the main pipeline 101.

The robot 100 has a spiral drive assembly 110 according to an embodiment of the invention and a module 150 coupled to the assembly 110 so that the module 150 can be pulled and pushed along the pipeline 101 by the spiral drive assembly 110.

FIG. 2(a) to (c) shows front views (upper portion of each figure) and side views (lower portion of each figure) of a portion of the spiral drive assembly 110. FIG. 2(a) shows the assembly 110 in a retracted condition, FIG. 2(b) shows the assembly 110 in a semi-deployed condition and FIG. 2(c) shows the assembly 110 in a fully deployed condition. FIG. 2(d) is an enlarged side view of the assembly 110 in the fully deployed condition. It is to be understood that the assembly 110 may be utilised when in the semi-deployed condition, depending on the diameter of the pipeline 101 in which the assembly 110 is located. Typically, in use, the assembly is moved from the retracted condition towards the fully deployed condition until a sufficient radially outward force is exerted by the assembly 110 on an inner wall of the pipeline 101 to permit operation of the assembly 110 in the manner described herein.

The assembly 110 has first and second body portions 110A, 110B each having a respective body or frame 110AB, 110BB by means of which components of the respective body portions 110A, 110B are supported.

The first body portion 110A has five drive roller support arms 111 RA, each hingedly connected at a first end to the first frame 110AB at pivot 111P that allows the support arms 111RA to pivot about a pivot axis of the pivot 111 P. A second end of each drive roller support arm 111 RA opposite the first carries a drive roller 111 R. The drive roller is arranged to rotate about a drive roller axis that is fixed with respect to the respective support arm 111RA, the drive roller axis being substantially parallel to the pivot axis of pivot 111 P. The roller is oriented at a helical pitch angle PA (FIG. 2(d)) of substantially 10 degrees in the present embodiment although other angles may be useful in some embodiments. The drive roller support arms 111 RA are arranged to be moved from the retracted position shown in FIG. 2(a) in which the drive rollers are located proximal the frame 110AB to the deployed position shown in FIG. 2(c) by means of a respective pivoting link arm 111 LA. Each drive roller support arm 111RA is coupled to its respective link arm 111LA at a location between the drive roller 111R and pivot 111P, in the present embodiment substantially midway therebetween. Each link arm 111 LA is pivotally connected at a first end to the respective link arm 111 LA and at a second end opposite the first to a respective slide rod slider element 111LAS that slides along a respective slide rod 111SR. The slide rods 111SR are oriented in a generally helical direction about the first body portion 110A at a pitch angle to the longitudinal axis L of the assembly 110 that is substantially equal to the helical pitch angle PA of the rollers 111 R with respect to a circumferential direction. Respective opposed first and second ends of the slide rods 111SR are held at substantially fixed positions with respect to the frame 110AB of the first body portion 110A.

Each slider element 111 LAS is pivotally connected to the second end of the respective link arm 111 LA by means of a link arm slider pivot 111LASP and constrained to slide along the respective slide rod 111 SR, which threads through the respective slider element 111 LAS.

A first slide rod spring member 111SRSA is provided around each slide rod 111SR between the link arm slider pivot 111 LASP and a push plate 110PP that is common to each slide rod 111SR and through which each slide rod 111SR passes. The push plate 110PP is constrained to be located between the link arm slider pivot 111 LASP and the first end of the slide rod 111SR and movable along the slide rod 111SR as described below. In the present embodiment the push plate 110PP is in the form of a substantially circular plate element oriented substantially normal to the longitudinal axis L of the assembly 110 and substantially coaxial thereof. It has five substantially arcuate apertures 11OPPA formed therein at circumferentially spaced locations a fixed radial distance from the longitudinal axis L of the assembly 110, corresponding to the locations of the slide rods 110SR.

A second slide rod spring member 111SRSB is provided around each slide rod 111SR between the link arm slider pivot 111 LASP and the second end of the slide rod 111SR.

It is to be understood that, in use, with the push plate 110PP located at or near the first end of each slide rod 111SR, the second slide rod spring member 111SRSB is configured to urge the link arm slider element 111 LAS towards the first end of the slide rod 111SR, causing each link arm 111 LA to cause the respective drive roller support arm 111RA to pivot radially inwardly, drawing the corresponding drive roller 111R radially inwardly.

If the push plate 110PP is slid axially towards the second ends of the slide rods 111SR, each first slide rod spring member 111SRSA becomes compressed and urges the corresponding link arm slider element 111 LAS to slide along the respective slide rod 111SR towards the second end thereof, against the action of the second slide rod spring member 111SRSB which also becomes compressed. Movement of the push plate 110PP thereby causes the respective link arm 111 LA to cause the respective drive roller support arm 111RA to pivot radially outwardly, thereby moving the corresponding drive roller 111 R radially outwardly.

It is to be understood that, in use, the push plate 110PP may be moved along the longitudinal axis of the assembly 110 a sufficient distance to cause the drive rollers 111 R to exert a sufficiently large pressure radially outwardly on a sidewall of the pipeline 101 in which the assembly 110 is located. Provided the push plate 110PP does not fully compress the first slide rod spring member 111SRSA, the first slide rod spring member 111SRSA permits resilient movement of the drive rollers 111 R in a radially inward direction to accommodate variations in distance between the frame 110AB and pipeline wall as the robot 100 moves along the pipeline.

In the embodiment of FIG. 2 the push plate 11OPP is arranged to be moved in a forward and backward direction relative to the frame 110AB of the first body portion 110A by means of a pneumatic cylinder 110PC1 that is fixed to and carried by the frame 110BB of the second body portion 110B. The cylinder 110PC1 has an actuator shaft or piston that is configured to be extended from or retracted into the cylinder 110PC1 when the motor is actuated in a forward or reverse direction. It is to be understood that the piston of the cylinder 110PC1 is configured to push on a thrust bearing 110TB in an axial direction along a longitudinal axis L of the assembly 110, the thrust bearing 110TB being coupled to the push plate 110PP to cause axial movement thereof, in turn.

As noted above, the assembly 110 has first and second body portions 110A, 110B. In the present embodiment the first and second body portions 110A, 110B are configured to be rotatable with respect to one another by means of a motor drive 110M1 shown in dashed outline in FIG. 2(e) and shown in FIG. 3(a). The motor drive 110M1 is also fixed to and carried by the frame 110BB of the second body portion 110B. The motor drive 110M1 is configured to cause rotation of a first gear wheel 110ABG1 which in turn causes rotation of a second gear wheel 110ABG2 that engages a corresponding toothed inner circumferential rim 110ABT of the frame 110AB of the first body portion 110A. Actuation of the motor drive 110M1 therefore causes relative rotation of the first and second body portions 110A, 110B about the longitudinal axis L of the assembly 110. FIG. 2(e) also shows a passageway 110AF' along a central longitudinal axis of the assembly 110 providing space for provision of cabling or the like, for example cabling supplying electrical power and/or data communications, and/or compressed gas lines such as compressed air, for example for one or more pneumatic actuators that may be carried by the robot 100. In the present embodiment the assembly 110 has a pair of motor drives 110M1 provided at diametrically opposite locations with respect to the longitudinal axis L as shown in FIG. 2(e).

It is to be understood that in the present embodiment, illustrated in FIG. 3(a), the assembly 110 is coupled to a module 150 of the robot 100 that carries six circumferentially disposed rollers 150R at each of two opposite ends of the module 150 to facilitate rolling of the module 150 along a pipeline 101, within the pipeline 101. The rollers 150R are arranged to rotate about a respective roller axis 150RA that is substantially normal to a longitudinal axis of the module 150. The roller axes are therefore positioned generally tangential to an outer circumferential portion of the module 150. The roller axis 150RA of each roller 150R is substantially fixed with respect to a body or frame 150B of the module in the present embodiment. Accordingly, the module 150 is arranged to resist rotational movement thereof about a longitudinal axis L thereof, relative to a pipeline 101 in which the module 150 may operate, due to a frictional force between the rollers 150R and pipeline wall.

The rollers 150R provided at each end of the module 150 may be carried and supported for rotation by first and second roller support members 15ORM1, 150RM2 that form part of the module 150. FIG. 3(b) shows a single roller support member 150R1, the second being substantially identical. The roller support members 15ORM1, 150RM2 are in the form of semi-circular hoop members each carrying three rollers 150R at angularly spaced locations around a periphery thereof. The roller support members 150RM2, 150RM2 are configured to be coupled together by means of magnet elements 15ORMM carried by each roller support member 150RM2 on one side thereof at free ends thereof, the free ends being of reduced thickness to allow the members to be joined in an overlapping arrangement to form a substantially circular member of substantially uniform thickness. It is to be understood that the respective free ends of a given support member 150RM1, 150RM2 carry magnet elements 5ORMM presenting opposite polarities at the exposed face. This allows substantially identical roller support members 15ORM1, 150RM2 to be magnetically coupled.

A 3D view showing two roller support members 150RM2, 150RM2 coupled together by means of the magnet elements 15ORMM is shown in FIG. 3(c) whilst a front view is shown in FIG. 3(d).

In assembled form the rollers 150R of the roller support members 15ORM1, 150RM2 are provided at angular intervals of 60 degrees about a circumference of the support members 15ORM1, 150RM2.

It is to be understood that roller support members 15ORM1, 150RM2 of different respective outside diameters may be provided to enable the same robot 100 to operate in pipelines 101 of different internal diameter. In some embodiments the roller support members 15ORM1, 150RM2 may have similar or substantially identical inside diameters, allowing them to be fitted to the same module 150, but of different outside diameters enabling the same module 150 to operate in pipelines 101 of different diameter.

The assembly 110 is coupled to the module 150 by means of a connector portion 130 having a hinge axle 131A that is shown substantially vertically oriented in the schematic side view image of FIG. 3(a). The hinge axle 131A is arranged to rotate relative to a substantially C-shaped hinge axle support frame 131F that is fixedly coupled to the second body portion 1108 of the assembly 110. A hinge axle tongue member 132T is carried by a connector support member 132 fixedly coupled to the module 150. The hinge axle tongue member 132T is pivotally connected to the hinge axle 131A to allow relative pivoting of the hinge axle tongue member 132T, about orthogonal vertical and horizontal axes A1, A2, with respect to the orientation depicted in FIG. 3(a). This feature allows the assembly 110 and module 150 to experience relative movement permitting negotiation of bends and variations of gradient within a pipeline, whilst preventing relative rotation, about the longitudinal axis of the assembly 110, of the second body portion 110B and module 150.

It is to be understood that, in some alternative embodiments, the hinge axle support frame 131 F may be coupled to the module 150 instead of the assembly 110 and the connector support member 132 may be coupled to the assembly 110 instead of the module 150.

In some embodiments, the hinge axle support frame 131 F of the connector portion 130 may be configured also to support the roller support members 15ORM1, 150RM2. In such embodiments the hinge axle support frame 131F may be coupled to the module 150 rather than the assembly 110. FIG. 3(e) shows an alternative embodiment of the hinge axle support frame 231 F that achieves this function. In the embodiment of FIG. 3(e) the hinge axle support frame 231F defines an annular groove 231FG oriented normal to an coaxial with a cylinder axis of the support frame 231. The annular groove 231FG may be sized snugly to receive a pair of roller support members 15ORM1, 150RM2 therein such that the roller support members 15ORM1, 150RM2 are able to be coupled to one another by means of the magnet elements 15ORMM thereby to be retained within the groove 231FG. Thus a width of the groove 231FG may be substantially equal to the width of the roller support members 15ORM1, 150RM2 and an inner diameter of the groove 231FG may be substantially equal to the inner diameter of the roller support members 15ORM1, 150RM2 such that the roller support members 15ORM1, 150RM2 may be readily coupled to the support frame 231F without undue movement of the roller support members 15ORM1, 150RM2 relative to the support frame 231 F in use. The groove 231 FG is provided such that, with the hinge axle support frame 231 F coupled to the module 150, the groove 231 FG is substantially coaxial with a longitudinal axis of the robot 100.

FIG. 3(f) shows the roller support frame 231 F coupled to a robot module 250 with roller support members 15ORM1, 150RM2 of relatively large outer diameter attached thereto whilst FIG. 3(g) shows the roller support frame 231 F coupled to a robot module with roller support members 250RM1, 250RM2 of relatively small outer diameter attached thereto. In the embodiment of FIG. 3(g) the roller support members 250RM1, 250RM2 are substantially of a minimum allowable diameter whereby a radially outermost portion of the rollers 250R barely protrudes beyond an outer diameter of the roller support frame 231 F. FIG. 4 shows an embodiment of the invention in which two spiral drive assemblies 110, 110', being a first assembly 110 and a second assembly 110', are coupled in a head to head manner to form a composite assembly 110C. That is, the assemblies 110, 110' are oriented in opposite directions with respect to a longitudinal axis L of the first assembly 110 or composite assembly 110C, the longitudinal axes of the assemblies 110, 110' being substantially co-linear in the orientation shown in FIG. 4. The assemblies 110, 110' are substantially identical but differ in that they are arranged such that the helical pitch angles of the drive rollers 111R are substantially equal but of opposite sign. FIG. 5 is a side view of the composite assembly 110C of FIG. 4.

The assemblies 110, 110 are coupled to one another in a manner allowing each assembly 110, 110' to rotate freely with respect to the other.

In the embodiment shown each of the assemblies is coupled to a respective module 150 (not shown in FIG. 4) similar to that shown in FIG. 3(a) and in a similar manner to that shown in FIG. 3(a). It is to be understood that, as noted above, the module 150 resists rotational movement relative to the pipeline 101 unless a sufficiently large torque is applied to the module 150.

In use, translational movement of the composite assembly 110C may be accomplished by driving the motor drives 110M1, 110M1' so as to cause rotation of the first body portions 110A, 110A' of each assembly 110, 110' in opposite directions, i.e. in a manner to cause counter-rotation of the first body portions 110A, 110A' with respect to one another and with respect to the pipeline 101 in which they are located. It is to be understood that this causes translational motion of the composite assembly 1 10C and the modules 150 attached thereto. It is to be understood that the modules 150 resist rotational movement and, provided the first body portions 110A, 110A' of the assemblies 110, 110' are caused to rotate relative to the respective second body portions 110B, 110B' at substantially equal speeds, rotation of the second body portions 110B, 110B' and in turn the modules 150 relative to one another and the pipeline 101 does not occur. Since the assemblies 110, 110' are substantially identical, the first body portions 110A, 110A' of the assemblies 110, 110' will rotate relative to the respective second body portions 110B, 110B' at substantially equal and opposite speeds provided the second motor drives 110M2, 110M2' are driven at substantially equal speeds.

In some embodiments, inertial measurement units (IMUs) incorporating miniature accelerometers and/or gyroscopes are employed to sense rotation of the first and second body portions of each assembly 110, 110'. This allows a feedback control system to be implemented to enable precise control of the drive motors 110M1, 110M1' and in turn the direction and speed of translation of the composite assembly 110C, and/or the direction and speed of rotation of the first or second body portions 110B, 110B'. Rotational encoders may be employed in addition or instead to ensure that the rotational speeds of the motors 110M1, 110M1' is as required to achieve the desired rotation and/or translation of one or more portions of the composite assembly 110C. Independent adjustment of the speed of rotation of the motors 110M1, 110M1' may be performed using pulse width modulation (PWM) technology in some embodiments. The ability to continuously alter the speed and direction of the individual motors 110M1, 110M1' in a pair of spiral drive assemblies 110, 110' allows both linear and rotational motion to be achieved, causing the second body portions and therefore modules 150 to experience both rotation and translation within a pipeline substantially simultaneously. This can reduce the time taken to place the robot 100 at a given location and in a given rotational orientation within a pipeline 101.

FIG. 6 illustrates a scenario in which the first body portion 110A of the first assembly 110 is rotated in a clockwise direction R1 as viewed in FIG. 6, with the second body portion 110B remaining in a substantially fixed rotational position, whilst the second first body portion 110A' of the second assembly 110 is rotated in an anticlockwise direction R2 as viewed in FIG. 6, with the second body portion 110B' remaining in a substantially fixed rotational position. The direction of net translational movement of the composite assembly 110C is indicated by arrow D. It is to be understood that rotation of the first body portions 110A, 110A' in the opposite directions to R1 and R2, respectively, will result in translational movement of the composite assembly 110C in the direction opposite arrow D. During longtitudinal motion of the composite assembly 110C, each spiral drive 110, 110' moves along the pipe such that the drive rollers 111 R describe a substantially helical path.

It is to be understood that, if the relative speeds of the motor drives 110M2, 110M2' are not the same, the second body portions 110B, 110B' and in turn the modules 150 will tend to experience a net rotational movement as well as translation along the pipeline 101, i.e. the movement of the second body portions 110B, 110B' and in turn the modules 150 will describe a substantially helical path.

It is to be understood that substantially pure rotational movement of the second body portions 110B, 110B' and in turn the modules 150 may be induced if the motor drives 110M1, 110M1' are driven so as to cause rotation of the first body portions 110A, 110A' of each assembly 110, 110' in the same direction. It is to be understood that, because the drive rollers 111R, 111R' of respective assemblies 110, 110' are of opposite helical pitch angle, an attempt to cause the first body portions 110A, 110A' of each assembly 110, 110' to rotate in the same direction results in the application of equal and opposite translational forces on the respective assemblies 110, 110' and a reaction torque on the second body portions 110B, 110B' that causes rotation of the second body portions 110B, 110B', and in turn the respective modules 150 coupled thereto. Accordingly, rotation of the second body portions 110B, 110B', and in turn the respective modules 150, with substantially no translation may be conveniently achieved. This feature allows any modules 150 coupled to the composite assembly 110C to be positioned precisely at a required angular position within a pipeline when required, for example when a maintenance or inspection operation is required.

FIG. 7 illustrates a scenario in which the first body portion 110A of the first assembly 110 is rotated in a clockwise direction R1 relative to the second body portion 110B as viewed in FIG. 6 whilst the first body portion 110A' of the second assembly 110 is also rotated in a clockwise direction R1 relative to the second body portion 110B' of the second assembly 110'. As a consequence of this relative motion, the first body portions 110A, 110A' remain substantially stationary and experience neither rotation nor translation with respect to the longitudinal axis L. This is because the first body first and second assemblies 110, 110' are being urged towards one another and exert substantially equal and opposite forces on one another. This effect may be referred to as a 'wedge' effect of the assemblies 110, 110' upon each other, resulting in the transfer of rotational motion to the second body portions 110B, 110B' of the first and second assemblies 110, 110' which both experience rotation about the longitudinal axis in anticlockwise direction R2. Thus, rotational motion of modules 150 coupled to the composite assembly 110C may be accomplished, whilst substantially no net translation of the composite assembly 110C occurs.

It is to be understood that, conversely, if the directions R1 of rotation of the first body portions 110A, 110A' relative to the second 110B, 110B' are reversed, the second body portions 110B, 110B' will also rotate in the opposite direction to R2. Again, substantially no net translation of the composite assembly 110C will occur.

Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", means "including but not limited to", and is not intended to (and does not) exclude other moieties, additives, components, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

Claims

CLAIMS: 1. A robot drive assembly for moving a robot along a substantially cylindrical pipeline within the pipeline, the assembly comprising first and second body portions, the first body portion being arranged to be rotated about a longitudinal axis of the assembly relative to the second body portion by drive means, wherein the first body portion has at least one drive roller coupled thereto, the robot being configured wherein rotation of the first body portion relative to the pipeline and second body portion about a longitudinal axis of the first body portion causes the at least one drive roller to rotate in contact with an inner wall of the pipeline about a roller axis oriented such that a resultant force acts on the first body portion in a direction to cause simultaneous rotation and translation of the first body portion with respect to the pipeline.
2. An assembly according to claim 1 comprising means for resisting rotation of the second body portion relative to the pipeline about the longitudinal axis of the assembly.
3. An assembly according to claim 2 wherein the means for resisting rotation of the second body portion comprises at least one auxiliary roller constrained to rotate about an axis normal to the longitudinal axis of the assembly.
4. An assembly according to any preceding claim wherein the at least one drive roller is movably coupled to the first body portion to permit movement of the drive roller towards and away from the first body portion.
5. An assembly according to claim 4 wherein the at least one drive roller is resiliently coupled to the first body portion by resilient coupling means, the resilient coupling means being configured to urge the at least one drive roller away from the first body portion and against an inner wall of the pipeline.
6. An assembly according to any preceding claim wherein the at least one drive roller is constrained to rotate about an axis having a first helical pitch angle with respect to the longitudinal axis of the assembly.
7. An assembly according to any preceding claim comprising actuator means configured to move the at least one roller towards and away from the first body portion between a retracted position and a deployed position, the retracted position being located radially inwardly of the deployed position.
8. An assembly according to any preceding claim comprising a plurality of drive rollers provided at angularly spaced locations about the longitudinal axis of the first body portion.
9. Apparatus comprising first and second robot drive assemblies according to any preceding claim, the apparatus being operable to cause the at least one drive roller of the second drive assembly to rotate in contact with the inner wall of the pipeline about an axis oriented such that a resultant force acts on the first body portion of the second drive assembly in a direction to cause simultaneous rotation and translation of the first body portion of the second drive assembly with respect to the pipeline, the direction of translation being opposite that of the first body portion of the first drive assembly.
10. Apparatus according to claim 9 wherein the at least one drive roller of the first drive assembly and the at least one drive roller of the second drive assembly are constrained to rotate about axes having helical pitch angles of opposite sense.
11. Apparatus according to claim 10 wherein the at least one drive roller of the first drive assembly and the at least one drive roller of the second drive assembly are constrained to rotate about axes having equal and opposite helical pitch angles.
12. Apparatus according to any one of claims 9 to 11 operable to prevent relative rotation of the first and second drive assemblies.
13. Apparatus according to claim 12 comprising locking means for locking the first and second drive assemblies to prevent relative rotation of the first and second assemblies.
14. A pipeline robot comprising a drive assembly according to any one of claims 1 to 8. 30
15. A pipeline robot according to claim 14 comprising a drive assembly coupled to at least one module and configured to cause translation of the drive assembly and module along a pipeline, the drive assembly being coupled to the at least one module by means of a flexible joint portion allowing pivoting of the module with respect to the drive portion about an axis substantially normal to a longitudinal axis of the assembly.
16. A pipeline robot according to claim 15 wherein the drive assembly is coupled to the at least one module by means of a flexible joint portion allowing pivoting of the module with respect to the drive portion about each of a pair of orthogonal axes substantially normal to a longitudinal axis of the assembly.
17. A pipeline robot according to claim 15 or claim 16 wherein the flexible joint portion is configured to prevent axial rotation of the module about a longitudinal axis of the assembly relative to the second body portion of the assembly.
18. A method of moving a robot along a substantially cylindrical pipeline within the pipeline, the method comprising providing an assembly comprising first and second body portions, the first body portion being arranged to be rotated about a longitudinal axis of the assembly relative to the second body portion by drive means, wherein the first body portion has at least one drive roller coupled thereto, the method comprising rotating the first body portion relative to the pipeline and second body portion about a longitudinal axis of the first body portion thereby to cause the at least one drive roller to rotate in contact with an inner wall of the pipeline about a roller axis oriented whereby a resultant force acts on the first body portion in a direction to cause simultaneous rotation and translation of the first body portion with respect to the pipeline.
19. An assembly, apparatus, pipeline robot or method substantially as hereinbefore described with reference to the accompanying drawings.