GB2119679A - Device for performing surface operations - Google Patents

Abstract

A remote control device for performing operations on a surface e.g. a strut or pipe 1, and having a guide member 2 on which a movable carrier 3 is mounted, the carrier having an operating head 13 movable relative to it, the head being adaptable for a variety of functions, for example for spray painting, profile tracing or shot blasting, so that such functions can be performed in positions which are difficult for access by human operators and which require accurate monitoring by a control system of the device. <IMAGE>

Description

SPECIFICATION Guide system This invention relates to a remote control device for use in performing operations on a surface.

In many environments the treatment of surfaces causes considerable difficulties, for example in gaining access to the surface. This is especially true in the oil and gas industries in the painting, cleaning or the like of off-shore structures. At the present time the legs of such structures are cleaned and painted manually from scaffolding erected around the legs.

This system suffers from several serious disadvantages. For example the operation can be very dangerous since operators may be working close to the sea in conditions of heavy swell or high waves. Further, scaffolding cannot be easily erected around obstructions which extend from the legs, such as fenders or cross-spars to other legs, and this makes it difficult to treatthese areas.

Difficulty has also arisen in the past in the monitoring and checking of profiles in, for example, pipelines. In many cases it is impossible to check accurately that a pipeline has not become deformed in shape, especially when the pipeline is buried and is too small to allow access by a human operator.

According to the present invention there is provided a remote control device for perfo#rming operations on a surface, the device having a guide member, a movable carrier for engagement with and movement along the guide member, an operating head connected with the carrier and movable relative to the carrier, and drive control means remote from the carrier for actuating and controlling the movement of the carrier and of the operating head.

The guide member may for example be a rigid or tensioned line extending between supports, such as a tensioned wire or toothed belt extending at a distance from and generally parallel to the surface; the carrier may then include driven rollers, toothed wheels or the like engaging with the wire or belt and rotatable to move the carrier along it, by a hydraulic motor. The guide member can provide a datum line for establishing the exact position of the carrier along the surface.

The carrier may be mounted on the guide member, and may have supports for engaging the surface to steady the carrier and maintain it in a desired attitude. Such supports may be in the form of adjustable legs which may carry rollers, wheels or the like for engaging the surface. The legs may be adjustable in length and/or in the angle between them.

The operating head is selected according to its desired function; it may be a nozzle or other outlet for applying paint, blasting sand or shot or otherwise supplying material to the surface from a distance, or it may itself contact the surface, for example to apply material directly or to abrade the surface or to monitor the profile of the surface.

The operating head may be connected to the carrier through an arm which can be pivotal at one end portion on the carrier and at its other end portion on the operating head. In many cases it is useful for the arm to be articulated so that the operating head can be moved in various directions across the surface and thereby provide extensive coverage from one position of the guide member.

Embodiments of this invention will now be described by. way of example with reference to the accompanying drawings in which: Fig. 1 is a side view of a remote control device of this invention; Fig. 2 is an end view corresponding to Fig. 1 with the articulated arm omitted for clarity; Fig. 3 is a schematic diagram showing the range of movement of the articulated arm of one embodiment of the invention; Fig. 4 is a sectional view of part of an articulated arm joint showing the position of a sensor gear arrangement for detecting movement of the arm in a device of this invention; Fig. 5 is a schematic diagram showing a typical claw arrangement for fitment on an articulated arm of a different device of this invention; Fig. 6 is a schematic diagram of a control circuit for use in a device of this invention;; Fig. 7 is a diagrammatic side view of a dented tubular structure showing how a contact member on the operating head of the present device can be used to detect the deviation of the structure from the correct shape.

Referring to Figs. 1 and 2 a cylindrical strut 1 extends from an offshore oil production platform (not shown), and this strut 1 is to be repainted. A wire-cable 2 is attached at one end to a fixture on the platform and at its other end to a clamp which is secured to the leg above, at or below the level of the sea as required. The fixture and clamp are positioned so that the cable 2 is held by each of them at an equal distance from the leg 1, and the cable 2 is then tensioned from the platform until taut. It then extends generally parallel to and spaced from the leg 1 as shown in Fig. 1.

A motorised carrier 3 is mounted on the tensioned cable 2, and held there by virtue of the cable passing between three grooved wheels 4 one of which 4A is connected to a hydraulic motor 15 driven by a control unit 5 on the carrier 3.

A pair of support legs 6 are pivotally connected to the carrier 3 and extend therefrom at an angle which can be altered by means of hydraulic rams extending between them. The legs 6 are also extendible in length and carry at their free ends rollers 7 mounted on spherical bearings 8 so as to be adjustable in attitude relative to the legs 6. The legs 6 are secured on the carrier 3 by a socketand-pin arrangement which can be released for removal of the legs 6.

The carrier 3 also has a housing 9 in which is disposed a further hydraulic motor 10 for powering an articulated arm 11. Hydraulic rams 1 2A, B, C extend between sections 11 A, B and a spray head 13 so that the sections 1 1 A, B and the spray head 13 are each pivotable relative to the others. The section 1 A can swivel about its mounting in the housing 9, and the spray head 13 can swivel about its mounting on the section 11 B by means of a motor 17.

The movement of the sections 1 A, B and the spray head 13 are controlled and dictated by a remote control device (not shown) mounted on the platform. The device is in the form of a joystick mechanism whose movements are translated into movement of the arm sections 1 1 A, B and the spray head 13 electrically along control cables 16 to the control unit 5.

In use, the carrier 3 is positioned at one end of the cable 2 and the pump supplying paint to the spray head is actuated. The control joystick on the platform is then moved by an operator to articulate arm 11 and cause the spray head 13 to move from side to side around the strut 1 , the head 13 swivelling to direct paint issuing from it against the strut 1. In the arrangement illustrated the spray head 13 can, by appropriate manoeuvring of the joystick, cover about twothirds of the circumference of the strut 1 from one position of the cable 2, and any obstructions such as fenders or adjoining struts can be avoided and painted around by control and adjustment of the arm sections 11 A, B and spray head 13. The legs 6 provide a steady base for easy control of the paint application.Fig. 3 shows schematically the full range of movement of the arm 1 1 relative to the carrier 3.

As painting continues the hydraulic motor 15 is actuated to drive the wheel 4A, thus moving the carrier 3 along the cable. With the arm 11 moving from side to side and the carrier 3 moving along the cable 2 the majority of the surface of the strut 1 can be painted in a single pass.

To complete the job the carrier 3 can be removed, the cable 2 released and re-positioned on the opposite side of the strut 1, the carrier 3 replaced on the cable, and the process repeated for those parts of the surface as yet unpainted.

If the strut is of varying diameter along its length this can be compensated for by adjusting the angle between the legs 6 so that the rollers 7 run flat on the surface of the strut and the legs 6 provide firm support for the carrier 3.

The legs 6 can be removed from the carrier 3 and the system used internally of pipes and other conduits for paint application, or for shot blasting, inspection or monitoring by substituting a shotblast head or camera or contact member for the spray head 1 3, or for lifting task by substituting a lifting claw 1 8 for the spray head 13 as shown in Fig. 5. In each case the carrier is held spaced from the conduit walls and the articulated arm 11 allows individual areas of the wall to be acted upon accurately by remote control.

Apart from its use on struts, conduits, and the like the device of this embodiment of the invention can be used for treating flat surfaces (such as walls of buildings) or contoured surfaces for a wide variety of purposes.

Improvements may be made whereby the articulated arm 1 1 is of a modular design allowing a variety of different types and sizes of arm to be manufactured using standard joint and arm components.

Each joint, whether for rotational or angular movement, can have a standard design which incorporates provision for the installation of a positively driven encoder for position sensing. This may take the form of a small sensor gear 20 positively driven by a larger location gear 21 on the pivot point of each joint as shown in Fig. 4.

This equipment provides, through suitable gearing, feed-back information with from 8 to 1 6-bit accuracy to enable control of the device.

In the standard joint provision may be made for the installation of electric, pneumatic, or hydraulic operation of the joint by the use of rams, screw feeds, or linear motors. The electronic positional feed back information is capable of driving a number of control circuits designed to permit flexibility in component selection.

The concept of modular design can be extended to the electronic components to the extent that the required circuit boards providing the functions for complete control can be so constructed that each board has the outputs required to provide for the control of an individual joint. Multi-function control is simply a matter of adding a board for each joint control required. By the addition of plug-in ancillaries these boards can be extended to provide any number of outputs for any number of joints.

Mechanically, the selection of components is free, and depends on the required capacity of the device. The mechanical design incorporates the modular joint design in conjunction with the electronic packages required.

A basic electronic circuit design for the system is shown in Fig. 6. The information from positional feed-back sensors 20, as described above, is fed back to an on-board microprocessor 22 which controls the operational circuitry of the device.

Incorporated in the processor 22 is the ability to communicate with a remote, hand-held operating console 23 through which an operator may input instructions. These instructions may be directed to the control of an individual joint, and at the request of the operator they may be retained in memory. The accumulation of a series of such instructions may be recalled at will thus enabling the device to repeat actions.

The hand-held controller incorporates a digital display which may indicate to the operator a variety of selected information on the program being run, the position of the device or information from an on-board tool.

Within the design of the hardware and the associated software is the provision for the incorporation of an arithmetic processor 26 which will enable predetermined tracking of the device, and for the incorporation of inputs from an external control processor 25 from which complex instructions may be input.

The positional feed-back information may be augmented by the incorporation of a series of detector heads 26 fitted to the palm of the device.

These detectors may be tactile sensors, displacement probes, sonic devices or digital cameras and provide information, which when displayed, stored, or otherwise used in conjunction with the positional information, enables the device to operate interactively with its operator or intelligently under its own command.

This aspect of operation is especially useful in remote inspection where it is possible to measure deviation from standard shape; where it is required to measure thickness of material in remote positions for record and survey purposes; and to provide, using the positional accuracy of the device, the ability at a future time to repeat the measurement and to compare it with the previous reading.

In the example of Fig. 7 the device is programmed to follow a part circular arc and a displacement probe on the operating head contacts the tubular structure to detect any deviation as the device describes the arc. Thus as the device describes an arc at regular intervals vertically down the tubular structure it traces out a series of shapes A to E. The device can then be programmed to inspect the vertical profile of the tubular structure and again carry out a series of regularly spaced profile checks. The collected information can then be displayed on a screen to build up a picture of the shape of the part of the tubular structure inspected.

This ability of the device to follow predetermined shapes, for example tubular structures is important in the application for remote painting in which the arc being described may be adjusted remotely at a change of section,.

or where the intersection of a tubular structure requires major program alteration the position of the device being fed-back to an operator will indicate progress and proximity to the required change.

Modifications and improvements may be incorporated without departing from the scope of the invention.

Claims (11)

1. A remote control device for performing operations on a surface, the device having a guide member, a movable carrier for engagement with and movement along the guide member, an operating head connected with the carrier and movable relative to the carrier, and drive control means remote from the carrier for actuating and controlling the movement of the carrier and of the operating head.

2. A device according to Claim 1, wherein the operating head has an outlet for passage therethrough of material to be applied to the surface.

3. A device according to Claim 1, wherein the operating head has a contact member for engaging the surface.

4. A device according to Claim 3, wherein the contact member is movable on the operating head.

5. A device according to any one of the preceding Claims, wherein the guide member has means for securing it in use remote from the surface.

6. A device according to any one of the preceding Claims, wherein the control means includes means for moving the operating head on a preprogrammed path.

7. A device according to any one of the preceding Claims, wherein sensor gears are provided to move in response to movement of the carrier and the operating head, the sensor gears being electrically connected with the control means.

8. A device according to any one of the preceding Claims, wherein the operating head is connected with the carrier through an arm which is pivotally connected at one end portion to the carrier and at its other end portion to the operating head.

9. A device according to Claim 8, wherein the arm is articulated.

10. A device according to any one of the preceding Claims, wherein the carrier has support legs for engaging the surface.

11. A remote control device for performing operations on a surface, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.