Patent Description:
Tasks performed on a drill floor, such as moving, positioning, and connecting pipe joints, usually involve a combination of manual work and heavy machinery. Such a combination involves a safety risk in itself. When pipe bodies, such as pup joints, subs, including crossovers, lifting subs, kelly valves, etc. are to be connected to a pipe string, a person will usually be involved for connecting a hook end of a tugger winch to carry the pipe body from a storage to the well centre. When in position over the well centre, a manual chain tongue will often be used to make up the threads of the pipe together with corresponding threads of the pipe string stick-up.

More recently, various robotic solutions have been proposed to grip, move and spin stand and pipes on a drill floor and thereby reduce or avoid the need for manual work. One such solution for lifting and gripping stands is sold under name "Hydraracker" and is commercially available from National Oilwell Varco (NOV) Inc. Another solution is disclosed in <CIT>. Common for these and other robotic drill floor solutions is that they require large, heavy, and often custom-made, robots to operate the end effectors, leaving large footprints. This may be a huge drawback, in particular when retrofitting for upgrading existing rigs.

<CIT> discloses attachment for making up and break out pipe connections. The attachment connects to a piece of heavy equipment, exemplified by the boom of an excavator.

In a first embodiment the invention relates to an end effector for gripping and spinning a pipe, the end effector comprising:.

The present applicant has surprisingly found out that by arranging the first connection interface with its normal parallel to the spinning axis, a better load case may be obtained, whereby the robot, to which the end effector is connectable, may utilize its lifting capacity more efficiently. This makes it possible to use smaller, commercially available robots for handling pipes on drilling rigs, where previously large, custom-made robots have been used. The normal of the first connection interface will usually, depending on the design of the robot, coincide with the outgoing rotation axis and normal on the robotic mounting face. If the robot is a <NUM>-axis robot, this also means that the end effector according to the invention may be hanging under, or alternatively being place above, the robotic arm when a pipe is held with its longitudinal axis vertical. This also means that a <NUM>th axis on a <NUM>-axis robot will be rotated <NUM>° relative to the length axis of the robotic arm when a pipe is held vertically, implying that the connection interface / tool flange on the robot is always substantially perpendicular to the pipe being held by the end effector. One of the reasons for the improved load distribution is that the arrangement with the first connection interface having its normal parallel to the spinning axis allows for a re-distribution of motors, cylinders etc. necessary for the operation of the end effector, effectively making it possible to move the spinning axis closer to the connection interface and the robot as such, thus reducing the lever arm. Another reason is the connection of the jaws to the robot through the head portion, as will become clearer when presenting the exemplary embodiment drawings below.

It should be noted that by "pipe" herein is meant shorter or longer pipes bodies, including, but not limited to, joints, pup joints and subs, such as cross-overs, lifting subs, kelly valves etc..

In one embodiment spinning of the pipe may be enabled by actively driven rollers provided on the jaws. The applicant has found that by providing actively driven rollers on the jaws, the head of the end effector, and thereby the whole end effector, may be made more compact since there is no need to provide spinning means centrally between the jaws. The compactness may be further emphasized by also providing the motors for operating the actively driven rollers on the jaws. In a preferred embodiment, the motors may be hydraulic. The motors may also be electric, but current hydraulic motors offer more torque per size than currently available electric motors. One motor may be provided per jaw to operate one actively driven roller each. Optionally, the hydraulic motors may be driven by external supply of hydraulics which may be controllable by means of a respective proportional control valve electrically controlled and synchronised by a control unit, such as a PLC. The control unit may be included in the robotic control system. Operation of the proportional control valve may be based on operator input and/or autonomous operation of the control system based on sensor data input from the end effector, as will be explained below. Providing a proportional control valve for each motor removes the need for a flow diverter in the head portion, further contributing the compactness of the end effector. To transfer torque from the motor to the actively driven roller, a shaft of each hydraulic motor may be connected to its respective actively driven roller by means of a sprocket and chain connection, which offer a simple, reliable and light-weight solution. In an alternative embodiment, a set of meshing gears may be used to obtain the connection.

In addition to the actively driven rollers, each jaw may be provided with one or more passive rollers, ensuring a uniform pressure on the pipes. The actively driven and/or the passive rollers may be serrated, optionally knurled with both vertical and horizontal serrations, to improve the frictional grip on the pipes.

In one embodiment, the pair of jaws may be operable between the open and gripping positions by means of a linear actuator. Use of a linear actuator to push the jaws to rotate together, typically via a link arm arrangement connecting the two jaws, provides a simple and compact solution for rotating the jaws towards and away from each other to grip and release a pipe, respectively. In one embodiment, the linear actuator may be a hydraulic actuator, further emphasizing the compactness of the end effector. A cylinder rod of the hydraulic actuator may then be connected to and act on the mentioned link arm arrangement effecting the movement between open and closed jaw positions. In an alternative embodiment, operating the jaws between open and closed position may be enabled by means of rotation motors acting on each jaw in the respective, rotary connections to the head portion.

In one embodiment, a cylinder portion of the hydraulic actuator may be connected to the head portion of the end effector. In a preferred embodiment the head portion is constituted by a single structural unit, improving load transfer enabling a compact and lightweight end effector. Connecting the linear actuator directly to the head portion, improves load transfer between the end effector and the robot.

In one embodiment, the head portion may be formed with a second connection interface, wherein the hydraulic actuator may be connected to the second connection interface, the second connection interface having a normal which is perpendicular to that of the first connection interface, the second connection interface being formed with an opening through which the cylinder rod extends in the direction of the normal of the second connection interface. In one embodiment, a flange of the cylinder portion of the hydraulic actuator may be bolted to the second connection interface. By forming the head portion with a second connection interface, and particularly, by forming this second connection interface with an opening/hole through which cylinder rod extends in use, the compactness of the end effector is further enhanced. In one embodiment, the first and second connection interfaces of the head portion may be connected via a trusswork, providing a light-weight structure with efficient transfer of loads between the end effector and the robot. In one embodiment, the head portion may be 3D printed to obtain the desired shape with.

In one embodiment, the end effector may be made substantially from aluminium. In particular, the head portion may be made from aluminium. The exception will typically be parts of the end effector, such as the rollers, that are in contact with the rotating pipe, which may need to be made more wear-resistant. These parts may e.g. be made from or covered with wear-resistant materials such as alloy-steel and/or various diamond or metal oxide coatings.

In one embodiment, the end effector may be provided with one or more sensors for monitoring the position of the jaws and/or the gripping pressure on a pipe. The robot, to which the end effector is connectable, will usually be controlled by an external control system, as mentioned above, which may or may not be integrated with a control system on a drilling rig on which the robot is placed and operating. By providing feedback on such parameters as the position and gripping pressure, the process may be optimized and made safer. By feeding these parameters to the control system and controlling the end effector in closed loop, operation of the end effector may also be automated.

In a second aspect, the invention relates to a robot to which an end effector according to the first aspect of the invention is connected.

The robot may be a <NUM>-axis robot with the end effector connected to the outgoing, <NUM>th axis. The implies that the outgoing, <NUM>th axis of the robot will also be substantially parallel to the spinning axis. <NUM>-axis robots have become a standard in many industrial applications due to their flexibility and usability and are commercially available from a number of different suppliers. It should be noted, however, that the end effector according to the first aspect of the invention may be used together with a variety of different robots and manipulators, including robots and robotic arms / manipulators having fewer or more than <NUM> axes, while still providing the same technical advantages.

In a third aspect, the invention relates to a robot assembly including a robot according to the second aspect as well as a control system for operating the robot with the end effector. The control system may control the supply of external power, such as hydraulic or electric power, to the robot, and be adapted to receive sensor data from the robot. The sensor data may be used by and operator of the robot to control its operation and/or the sensor data may be used to operate the robot in closed loop.

In fourth aspect, the invention relates to drilling installation including a robot assembly according to the second aspect of the invention.

In the following is described an example of a preferred embodiment illustrated in the accompanying drawings, wherein:.

In the following, the reference numeral <NUM> will be used to denote an end effector according to the first aspect of the invention, while reference numerals <NUM> and <NUM> will be used to denote a robot and a drilling installation according to the second and fourth aspects of the invention, respectively. Identical reference numerals refer to identical or similar features in the drawings. Various features in the drawings are not necessarily drawing to scale. External power and communication connections to the end effector <NUM> and robot <NUM> are generally not shown in the figures for simplicity.

In <FIG> an end effector <NUM> according to the first aspect of the invention is shown in perspective view. The end effector <NUM> is adapted to grip and spin a pipe <NUM>, as shown in <FIG> and discussed in more detail below. A head portion <NUM> of the end effector <NUM> includes a first connection interface <NUM> for connecting the end effector <NUM> to a mounting face on a robotic arm, as shown in <FIG>. A pair of jaws <NUM> are connected to the head portion <NUM> via rods <NUM> defining respective rotation axes for the jaws <NUM> on each side of the first connection interface <NUM>. The first connection interface <NUM> has a normal N1. Each of the jaws <NUM> includes an upper portion 8a and a lower portion 8b, the jaws <NUM> being connected to each other via the head portion <NUM> and via a link arm arrangement <NUM> as will be discussed in more detail below. The end effector <NUM> further includes a spinner <NUM>, here in the form of a pair of actively driven rollers; one on each jaw <NUM>. The actively driven rollers <NUM> are rotatably suspended between the upper and lower portions 8a, b of the jaws <NUM>, and operable by means of a respective hydraulic motor <NUM>, only shown schematically, provided on each jaw <NUM>, also between the upper and lower portions 8a, 8b of the jaws <NUM>. A rotatable shaft <NUM> of each hydraulic motor <NUM> is connected to its respective, actively driven roller <NUM> by means of a chain <NUM> and sprockets <NUM>. A pair of passive rollers <NUM>, one on each jaw <NUM>, is also provided between the upper and lower portions 8a, b of the jaws <NUM> at distal ends of the jaws <NUM> to ensure a uniform grip on a pipe. A linear actuator <NUM>, here in the form of a hydraulic actuator, as best seen in <FIG> and <FIG>, is connected to a second connection interface <NUM> on the head portion <NUM>. The head portion <NUM> is best seen in the enlarged view of <FIG>. A cylinder portion <NUM> of the hydraulic cylinder <NUM> is bolted to the second connection interface <NUM> with a cylinder rod <NUM> extending through a hole <NUM> in the second connection interface <NUM>, the cylinder rod <NUM> extending in the direction of the normal N2 of the second connection interface <NUM>, where the normal of the second connection <NUM> interface N2 is perpendicular to the normal N1 of the first connection interface <NUM>.

To move the end effector <NUM> from its open position, as shown in <FIG>, to its gripping position, as shown in <FIG>, the hydraulic cylinder <NUM> is pressurized to push the cylinder rod <NUM> forwardly in its length direction. The cylinder rod <NUM> is connected to the link arm arrangement <NUM> connecting the jaws <NUM> together. The link arm arrangement <NUM> includes a pair of first link arms <NUM>, each first link arm <NUM> being rotatably connected around a vertical axis to a respective jaw <NUM> between the upper portion 8a and the lower portion 8b at a proximal end, while a distal end of each first link arm <NUM> is rotatably connected to a second link arm <NUM> around respective vertical axes. The second link arm <NUM> is connected to the distal end of the cylinder rod <NUM>, whereby pushing the cylinder rod <NUM> forward in its length direction rotates the jaws <NUM> around their respective rotation rods <NUM> to swing the outer / distal ends of the jaws <NUM>, including the actively driven rollers <NUM> and the passive rollers <NUM>, inwardly to grip a pipe <NUM>, as shown in <FIG>. Spinning of the pipe <NUM>, by means of the actively driven rollers <NUM>, may now commence around the spinning axis A, corresponding substantially to the centre axis of the pipe. By "substantially" in this context is meant that the grip on the pipe <NUM> may not always be perfectly symmetric, and there may be a small, negligible deviation between the spinning axis A and the centre axis of the pipe <NUM>. When the pipe <NUM> has been spun into a pipe string <NUM>, as indicated in <FIG>, the cylinder rod <NUM> may be driven backwardly to release the grip on the pipe <NUM>, whereby the robot <NUM> may move the end effector <NUM> to another position, e.g. to grab a new pipe <NUM> from a set-back <NUM> as shown in <FIG>.

<FIG> shows a robot <NUM> according to the second aspect of the invention. In the shown embodiment, the robot is a <NUM>-axis robot as commercially available from a robot supplier. The connection interface <NUM> of the end effector <NUM> is connected to the (not shown) mounting face of the robot <NUM> at the outgoing, <NUM>th axis, sometimes also referred to as the T axis. As can be seen from the figure, the <NUM>th axis, sometimes also referred to as the B axis, is tilted <NUM>° downwardly in the shown position so that the length axis of the pipe and the spinning axis A is substantially vertical.

An enlarged detailed view of the head portion <NUM> is shown in <FIG>. As can be seen, the first connection interface includes a plurality of bolt holes <NUM> for connecting the end effector <NUM> to a mounting face on the robot <NUM>. In the shown embodiment, the first connection interface <NUM> is formed as a circular disc. However, different types of robots may have different, standardized connection faces, requiring different types of shapes for corresponding connection interfaces. In the shown embodiment, first connection interface <NUM> is connected to the second connection interface <NUM> via a truss work <NUM> with arms <NUM>, each of which has a hole <NUM> at its distal end, extending to the side of the first connection interface <NUM> for connecting the jaws <NUM> to the head portion <NUM> via the rotation rods <NUM>, as e.g. shown in <FIG>. In the shown embodiment, the head portion <NUM> is produced by 3D printing aluminium.

The robotic control system may be operable by means of hardware comprising several distinct elements, and by means of a suitably programmed computer.

Claim 1:
End effector (<NUM>) for gripping and spinning a pipe (<NUM>), the end effector (<NUM>) comprising:
- a head portion (<NUM>) including a first connection interface (<NUM>) for connecting the end effector to a mounting face of a robotic arm (<NUM>),
- a pair of jaws (<NUM>) rotatably connected to the head portion (<NUM>) between an open position and a gripping position;
- a spinner (<NUM>) for spinning a pipe (<NUM>) held by the pair of jaws (<NUM>) in the gripping position around a spinning axis (A) generally corresponding to a longitudinal centre axis of the pipe; characterised in that the first connection interface (<NUM>) has a normal (N1) which is substantially parallel to the spinning axis (A).