Crane system

Abstract

The present invention relates to a crane system (2) comprising a trolley (7) to support a load and movable about a horizontal direction to provide movement of the load in a horizontal direction accordingly. A carrying member (10) is supported by the trolley (7) and configured to carry the load in use and a sensor (22,24) is provided to measure the angle of the carrying member (10) relative to a datum (18). A controller (28) is configured to provide a signal to effect movement of the trolley (7) in use and the controller (28) is configured to determine an operating speed of the trolley (7) when said angle is non-zero, and the where said operating speed is variable.

Description

[0001] Crane System

[0002] The present disclosure relates to a system for providing movement of a crane system.

[0003] Background of the Invention

[0004] In prior art bridge cranes, a trolley is attached to a rail, gantry or other support. For smaller systems, the trolley may be mounted using a free-wheels, bearings or the like. The trolley may therefore be manually dragged along the rail. For larger systems, the trolley comprises a motor that may be driven along the rail. The motor is typically electronically controlled via a remote control. For example, the remote control comprises separate buttons to effective movement of the trolley in opposing directions.

[0005] The inventor has found numerous problems with the prior art system. Firstly, it may be difficult for the user to determine which button on the remote control corresponds to which direction on the rail. For example, if the user rotates their positions by 180 degrees, then the controls are effectively reversed. This may lead to the user wasting time by initially moving in the incorrect direction and / or could potentially create hazardous situations.

[0006] Furthermore, the responsiveness or sensitivity of the movement controls can be low. For example, a short press of the button may lead to delayed movement and / or a larger movement than required. It can therefore be difficult to accurately move the trolley into the desired position. This can cause wasted time, or create hazardous situations (e.g. the load may swing if the trolley is not directly above the load).

[0007] A prior art solution is provided in WO 2013 / 041770 A1 . In this document, the crane may be moved using a “by-hand follower” system in which the crane may be dragged by the user by determining if there is angle between the rope the vertical direction. However, the system is simple in nature, and the control of the position of the crane may be difficult as the crane may undershoot or overshoot the target.

[0008] The present invention aims to overcome or ameliorate one or more of the above problems.

[0009] Statement of Invention

[0010] According to a first aspect, there is provided: a crane system comprising: a trolley or hoist to support a load and movable about a horizontal direction to provide movement of the load in a horizontal direction accordingly; a carrying member supported by the trolley / hoist and configured to carry the load in use; a sensor to measure the angle of the carrying member relative to a datum; a controller configured to provide a signal to effect movement of the trolley / hoist in use; and where the controller is configured to determine an operating speed of the trolley / hoist when said angle is non-zero, and the where said operating speed is variable.

[0011] The sensor may detect angle of an end of the carrying member or connector thereon relative to a datum. The system may provide a following / tracking routine. The following / tracking routine may move the trolley to a position aligned with a connector (e.g. directly above).

[0012] The operating speed may be a function of said angle. The controller may be configured to reduce the speed of the trolley as said angle decreases. Said operating speed may be configured to be proportional to a diminishing function of the angle (i.e. the rate at which the function increases decreases with increasing angle). Said operating speed may be configured to be proportional to the square root of the angle. The operating speed may be a maximum operating speed of the trolley. The datum may comprise the vertical direction.

[0013] The crane system may comprise an inverter to provide power to a motor to drive the trolley in use (e.g. in the horizontal direction). The controller may be configured to vary the frequency of the signal input to the inverter. The frequency may be varied as a function of said angle and / or speed. The frequency may be proportional to the desired driving speed.

[0014] The controller may be configured to move the trolley in a direction to reduce said angle. The controller may be configured to drive the trolley in direction toward an end of the carrying member or connector thereof. The controller may be configured to move the trolley in one direction if the measured angle is positive and an opposing direction is the angle is negative.

[0015] The crane system may comprise a controller having a manually operatable input (e.g. a remote controller). The user may activate input during movement of the trolley (i.e. the input must be maintained during movement). Movement of the trolley may be prevented if the input is released or deactivated.

[0016] The angle may be measured using an angle measurement sensor. The angle measurement sensor may be configured to determine a real and / or virtual angle of the carrying member. The angle sensor may comprise one or more inclinometer. The angle sensor may comprise a rotary encoder.

[0017] The sensor may comprise an optical, time-of-flight or radio-based system. The sensor may determine the effective position the carrying member, a connector thereof or a load thereon to determine said virtual angle.

[0018] The operating speed may be a function of the length of the carrying member. The controller may be configured to reduce the speed of the trolley as said length decreases. Said operating speed may be configured to be proportional to the square root of the length. The crane system may comprise a sensor to determine the effective length of the carrying member. The sensor may comprise an encoder. The encoder may be provided on the hoist motor, gear and / or drum axis. The sensor may be provided by an inverter to drive the hoist motor (i.e. the driving speed / amount may be used to determine the length of payout of the carrying member). The sensor may comprise a visual, time-of- flight or radio-based system configured to determine a virtual length of the carrying member.

[0019] The operating speed may be a function of a maximum deceleration (or ramp time) of the trolley. The controller may be configured to reduce the speed of the trolley as said deceleration (or ramp time) decreases. Said operating speed may be configured to be proportional to the square root of the deceleration.

[0020] The trolley may be mounted to a bridge or gantry. The bridge or gantry may be movable about one or more axis. The trolley may be movable in two horizontal directions (i.e. movement may be effect by movement of the trolley and the gantry). The controller may measure the angle of carrying member in the respective dimensions. The controller may determine an operating speed in the respective dimensions. The controller may be configured to drive the trolley in the respective dimensions.

[0021] The controller may be configured to continually monitor said angle and control the speed of the trolley accordingly. The controller may operate in real time. The controller may comprise a proportional controller to control said speed. The speed of the trolley may be reduced to zero as the measured angle becomes zero.

[0022] The trolley may comprise a hoist. The hoist may comprise a hoist mechanism. The hoist mechanism may vary the length of the varying member. The hoist mechanism may comprise a motor to vary the length thereof. The hoist / trolley may comprise a motor to effect movement of the horizontal position thereof. The bridge or gantry may comprise a motor to effect movement of the horizontal position thereof.

[0023] The crane may comprise an overhead and / or jib crane.

[0024] According to further aspect there is provided: a method of operating a crane system comprising: providing a trolley / hoist to support a load and movable about a horizontal direction to provide movement of the load in a horizontal direction accordingly; providing a carrying member supported by the trolley / hoist and configured to carrying the load in use; detecting an angle of the carrying member relative to a datum; controlling movement of the trolley / hoist in use; and determining an operating speed of the trolley / hoist when said angle is non-zero, and the where said operating speed is variable.

[0025] According to further aspect there is provided: a computer program or computer readable medium comprising program instructions which, when executed by the computer, cause the computer to carry out a computer process implementing the method according to claim 14.

[0026] Any aspect of the invention may be combined with any other aspect of the invention where practicable.

[0027] Description

[0028] Embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings:

[0029] Figure 1A shows a schematic view of a first crane system;

[0030] Figure 1B shows a schematic view of a second crane system;

[0031] Figure 2 shows a schematic view of a carrying member of the system;

[0032] Figure 3 shows a schematic view of a control system; Figure 4 shows a schematic view of operation of the system.

[0033] A crane system 2 is shown schematically in figure 1 . The crane comprises a bridge or overhead crane. The crane 2 comprises bridge portion 4. A hoist mechanism 6 is mounted to the bridge portion 4 and is movable along the length thereof. The bridge 4 may comprise a girder, beam, rail, jib or the like. The hoist 6 comprises a carriage or trolley 7 movably mounted to the bridge 4. The carriage may comprise a wheel, bearing or roller to provide movement thereof. Movement may be effected by a motor 8 provided on the trolley 7. The motor may comprise a gearbox or the like. The gearbox may then be operatively connected to the wheel / bearing / roller. In other embodiments, the trolley 7 may be effected via external driving means (e.g. via a screw drive or endless loop).

[0034] A motor may be provided to effect movement of the gantry / bridge portion, where the gantry / bridge 4 is movable. The motor may comprise a gearbox. The gearbox may be connected to wheel or the like to drive the gantry / bridge. The gantry / bridge 4 may be mounted to gantry, rail, guide or support structure to allow horizontal movement thereof. The gantry / bridge 4 may be movable along a rail 9 or pair or rails. The bridge may comprise one or more wheel 11 configured to engage the ground, rail or the support structure where provided. The bridge may comprise a plurality of legs 13. The wheels 11 are provided on the legs 13. This provides a gantry crane like arrangement.

[0035] In the embodiment shown in figure 1A, the rail 9 may be provided on fixed structure. The wheels 11 are therefore mounted directly to the bridge 4. This provides an overhead crane like arrangement.

[0036] A carrying member 10 is provided on the hoist 6 to allow connection to a load in use. The carrying member 10 is typically flexible. For example, the carrying member may comprise a rope, cable or chain. The rope may comprise a metallic (e.g. steel) or polymeric / synthetic rope. In some embodiments, the carrying member may be rigid or comprise rigid portions. A connector 12 is provided at an end of the carrying member 10 for connection to a load. The connector 12 may comprise a hook, eyelet, carabiner or the like. The carrying member 10 is presented in a schematic manner in figure 1 , and it can be appreciated that the carrying member 10 may be looped over a pulley (e.g. to form a pulley system) and / or comprises a plurality of parallel members. The “end” of the carrying member 10 may comprise a lowermost point of the carrying member 10 in use.

[0037] The crane 2 may be configured to raise / lower the load. For example, the hoist 6 may comprise a winch, pulley system and / or other hoisting mechanism for effecting movement of the load in a vertical direction in use. The winch / pulley may pay-out or pay-in the carrying member 10. A drum (e.g. a rope drum) or spindle may be provided to store the carrying member 10. A motor may be provided to effect movement in the vertical direction (i.e. to rotate the drum). The motor may comprise a gearbox.

[0038] A remote controller 14 may be provided to provide operation of the crane 2. The remote controller 14 may allow adjustment of the position of the trolley 7 along the bridge 4 and / or the vertical position of the load. The remote controller 14 may be wired or wireless. The remote controller 14 may comprise a pendant or radio controller.

[0039] It can be appreciated that the exact form of the crane is not pertinent to the invention at hand, and in generally terms, the system comprises a hoist movable in a horizontal direction. The crane may comprise any suitable type of crane, for example one or more of: an overhead / bridge crane; a tower crane; a gantry crane (e.g. the bridge portions is movable); deck crane; jib crane; or hammerhead crane. Typically, any of the aforementioned driving motors are electric motors. The system 2 is configured to determine if the connector 12 is displaced in a horizontal direction 16 away a direction 18 vertically below the trolley 7. If said displacement is detected, then the trolley 7 is configured to be driven such that the trolley 7 is vertically above the connector 12. In the example shown in figure 1 , the connector 12 is moved from position 18 to 18’. The hoist moves in direction 20 from 18 to 18’ accordingly. The trolley 7 therefore follows or tracks the horizontal position of the connector 12. This allows the user to move the horizontal position of the trolley 7 without the need for specific controls (e.g. the remote controller 14, and allowing movement of a trolley 7 that would otherwise not be suitable for manual movement. The system is specifically configured to drive the trolley 7 at a speed which prevents over / under shooting, which operating at an efficient speed.

[0040] Operation of the system is described in further detail in figures 2 and 3. In a first embodiment, an angle sensor is used to measure the angle 0 of the carrying member 10 relative to a datum to determine the horizontal displacement X. Typically, this datum comprises the vertical direction 18. The system 2 may comprises any suitable arrangement for determining the angle of the carrying member 10, for example, the apparatus disclosed in W02013041770A1 , incorporated herein by reference.

[0041] For a carrying member 10 of a given length, L, and for small 0:

[0042] The system can therefore determine the displacement of the connector 12, and move trolley 7 by said distance accordingly.

[0043] Typically, it is desirable that the trolley 7 moves in a fashion that accurately adjusts the position (i.e. the trolley 7 does not undershoot or overshoot said position). The speed of the trolley 7 should therefore be controlled to ensure accuracy. An acceleration, a, is determined as a function of hoist maximum speed (i.e. horizontal speed), vnOm, a ramp time, T, and an intermediate speed, v, at time, t. It can be understood that the speed or acceleration may components in either the trolley 7 or gantry 4 movement directions. The ramp time, T, is typically a design parameter that is determined based on physical dimensions (crane and load weight) and power of traversing machinery. T is the time the machinery can ramp from zero to full speed. The maximum speed of the trolley is also a design parameter. The time taken to stop the trolley 7 at a given speed, v, is therefore:

[0044] If the intermediate speed, v, is selected such that the trolley 7 has time to ramp down (i.e. slow to zero speed) with a constant acceleration whilst travelling distance X:

[0045] The maximum velocity that the trolley 7 can be driven taking into account the ramp time and the nominal speed of the trolley 7 is therefore:

[0046] Where c is a tuning value used to adjust the speed of the trolley 7 during the following / tracking. When c=1 , the calculated speed will not result in overshoot. When c<1 , travel speed will be slower and with c>1 travel speed will be too fast, and there will be overshoot when cranes ramps down to zero angle. For negative angles, the absolute value can be taken of the angle, and the calculated speed is in opposite direction. It can be seen that the maximum velocity is function of the length of the carrying member, L, vnOm (and the maximum safe deceleration accordingly), and the measured angle 0. The velocity is proportional to the square root of said variable.

[0047] The system can therefore be defined in a proportional control system (i.e. a P- controller) with a gain function defined as:

[0048] Where the direction of movement is assigned according to:

[0049] The trolley 7 will therefore move in one direction when the angle is positive and the opposing direction when the angle is negative. It can be appreciated that the system is configured to ensure this correlates with the correct movement to allow the following function. In summary, the system uses a proportional control regime to ensure that the trolley 7 moves in accurate fashion.

[0050] The signal for the measured angle 0 may be filtered. For example, this may filter out noise from the sensor and / or filter out angles which may not be realistic (e.g. angles greater than 90 degrees, or angles that differs significantly from previous values). This may also help to ensure that the control regime remains stable. A low pass filter may desirable be used to prevent oscillations.

[0051] As the effective length of the carrying member 10 may vary during use of the system 2 (e.g. due to hoisting thereof), the system 2 is configured to update the length in the aforementioned control regime. The system may monitor the pay- in / pay-out of the carrying member 2 or otherwise determine the effective thereof. The effective length is updated periodically, for example, between every 0.1 and 5 seconds. The effective length can also be updated when the length changes by some set interval. Typical change interval can be 1 mm to 10 cm. The length sensor may comprise an external encoder (e.g. pulse or absolute) on the hoist motor, gear or drum axis (e.g. to monitor number of axle / drum rotations). Alternatively, the length may be determined via an inverter which monitors hoisting position (e.g. using motor encoder or motor speed feedback).

[0052] Typically, the trolley 7 is effected by an inverter drive which operate in accordance with an input frequency (i.e. the input frequency changes the speed / power thereof). The driving frequency, f, may be determined by: where fnOm is nominal frequency and vnOm is nominal velocity. Frequency (and therefore travel speed) is limited by nominal frequency, so f and v maximum values are limited by fnom and Vnom, respectively.

[0053] The system is shown schematically in figure 3. An angle sensor 22 is provided to measure the angle, 0, of the carrying member 10 relative to vertical. A variety of methods may be used to determine the angle or inclination of the carrying member, for example, one or more of:

[0054] • An inclinometer attached to a portion of carrying member 10 and / or the connector 12. The inclinometer may be attached near a terminal end of the carrying member 10 (the end adjacent the trolley 7 and / or the connector 12). Multiple inclinometers may be provided. The inclinometers may be spaced along the axis of the carrying member 10. The angle may be determined as an average of the inclinometers. The sensor(s) may be provided at or adjacent a fixed end of the carrying member 10 (i.e. the end not configured to be reeled in). This ensures the sensor is not fed into a drum etc.

[0055] • A potentiometer or encoder on fixed end joints or pivots connecting the carrying member 10 to the trolley 7.

[0056] • Using an optical sensor 24. For example, one or more camera may be provided to determine the position of the carrying member 10 and / or connector 12. Two or more cameras may be used to capture a stereo image of the carrying member / connector, thereby allowing determination of the position thereof. The system may use machine learning or Al to allow accurate detection.

[0057] • Using time-of-flight (ToF) type systems. For example, RADAR, LIDAR, or laser range finding systems may be used. This allows passive detection of the position of the carrying member / connector

[0058] • Using active tracking systems. The carrying member / connector is configured to emit a signal allowing determination of the position thereof. For example, the system may use one or more of: ultrasound; a radio beacon; or an ultra wide band (UWB) radio.

[0059] It can be appreciated that where optical, ToF, or active tracking systems are used to determine the position of the carrying member / connector, a virtual angle may be determined (i.e. rather than calculating the physical angle, a virtual angle is calculated given a known length and position of the carrying member 10 / connector 12). In some embodiments, the angle need not be determined at all, as the position or displacement, X, can be determined in absolute terms. Similarly, such systems can be used to determine the effective rope length, L, or other variable in the proportional control regime.

[0060] The angle sensor 22, length sensor 26, and optical / ToF / active tracking system 24 (where provided) are configured to communicate with a controller 28. The controller 28 comprises any suitable processing system. The controller 28 may comprise one or more of: a processor; microprocessor; microcontroller; volatile and / or non-volatile memory; SoC etc. The controller 28 may comprise an analog and / or digital computing device. The controller 28 may comprises an embedded or industrial PLC. The controller 28 is configured to provide the control regime as previously described. Any of the above parameters (e.g. T, Vnom, fnom, c,) may be stored to controller memory. The parameters may be input and / or reconfigured as necessary by the user.

[0061] The controller 28 is operatively connected to an inverter 30. The controller 28 can provide appropriate frequencies to the inverter to drive the motor 8 accordingly. Where the trolley 7 is not driven by an onboard motor 8, then controller 28 is operatively connected to offboard driving means accordingly. In some embodiments, the controller 28 may be embedded or integrated with the inverter 30.

[0062] The remote control 14 is operatively connected to the controller 28. The remote control 14 comprises one or more inputs to allows control of the trolley 7. The inputs may provide movement in the horizontal direction (i.e. along the bridge 4 or perpendicular movement of the bridge itself) and / or the vertical direction. This may allow the system 2 to act in a conventional manner.

[0063] In some embodiments, the user may be required to active one or more input during operation. Typically, the input is provided on the remote control 14. This helps to increase safety of the system and / or prevent accidental movements. The user may be required to hold down the input during operation (i.e. to provide a dead-man’s type switch). If the input is released, then the motor / hoist may cease to be driven and / or brakes may be applied.

[0064] Operation of the invention

[0065] In a first step 32, the connector 12 is moved towards the desired position by the user (e.g. by physically pushing or dragging). This generates an angle 0 between the carrying member 10 and the vertical direction 18. In the next step 34, the user actuates an input on the remote control 14. A signal is transmitted to the controller 28, and the following or tracking system is activated. Typically, the user is required to maintain actuation of the input during the following routine.

[0066] In the next step 36, the system is configured to determine the angle of the carrying member 10 / connector 12 relative to the datum (i.e. vertical direction). This is performed by the angle sensor 22 or optical / ToF sensor 24. In step 38, the desired driving speed of the trolley 7 is determined by the controller 28 in accordance with above control regime. Once the angle and speed are calculated, the trolley 7 is moved in step 40 along the bridge 4 to a position vertically above the connector 12. The speed at which the trolley 7 moves is determined by the above control regime. The angle, 0, is continuously monitored, and the desired speed is adjusted continuously accordingly.

[0067] The trolley 7 moves to a position where angle, 0, between the vertical axis is zero or close thereto (e.g. less than 1 or less than 0.5 degrees). In the final step 42, once the trolley 7 is in the desired position, the input can be released by the user. This process can be repeated as many times as necessary.

[0068] It can be appreciated that during the steps 36-40, the user may continually move the connector 12 (i.e. to drag or lead the trolley 7). The system 2 therefore continually monitors the angle of the carrying member / connector and adjusts the speed accordingly (i.e. the system iterates steps 36-40). When the user continually moves the connector 12, the trolley 7 may move at the maximum speed (vnOm). This may provide a “Follow Me” function. Once the user stops moving the connector 12, the system detects the angle is reducing with movement of the hoist, and the actual speed may ramp down accordingly (i.e. in a proportional manner).

[0069] In other examples, the user moves the connector 12 to the desired position, and then activates the system. The system moves the trolley 7 to desired position in the shortest time possible (e.g. by moving at a maximum speed that allows stopping time). This may provide a position tracking system.

[0070] Movement may be provided in any direction along the bridge. Where the hoist is capable of movement in two horizontal dimensions (e.g. where a gantry crane is provided), then the system may be configured to provide following / tracking accordingly. For example, the angle sensor may be configured to detect the angle, 0, relative to the vertical axis, and also the angle in which the carrying member / connector extends in the horizontal plane. The horizontal displacement X may therefore comprise a vector (for example, Xxis component in the left-right direction in figure 1 and Xyis the in-out page direction). The vector components of the displacement X can then be used to determine drive speeds and / or drive respective motors in the respective dimensions. The hoist may therefore be movable about a plane.

[0071] Typically, the system 2 is used when a load is not supported by the hoist 6. This helps to ensure safe operation of the system (e.g. as the user is not manually manipulating heavy loads). In some cases, the user may use the system 2 when a load is supported, for example, when the load is sufficiently light.

[0072] The present system allows the user to manually manipulate the position of a connector or hoist of a crane system whilst still providing mechanical power thereto. This provides the user with precise control of the position of the hoist, whilst ensuring the user is not over-exerting themselves. The system therefore provides improved productivity and safety.

[0073] The system ensures that hoist is driven at the appropriate speed to prevent under- or over-shooting of the hoist. This reduces the need for corrective operations by the user, ensuring accurate and efficient usage. The speed is also optimised to allow driving at a maximum speed whilst allowing sufficient time for the hoist to slow.

Claims

Claims:1 . A crane system (2) comprising: a trolley (7) to support a load and movable about a horizontal direction to provide movement of the load in a horizontal direction accordingly; a carrying member (10) supported by the trolley (7) and configured to carry the load in use; a sensor (22,24) to measure the angle of the carrying member (10) relative to a datum (18); a controller (28) configured to provide a signal to effect movement of the trolley (7) in use; and where the controller (28) is configured to determine an operating speed of the trolley (7) when said angle is non-zero, and the where said operating speed is variable.

2. A crane system according to claim 1 , where the operating speed is a function of said angle.

3. A crane system according to claim 2, where the controller (28) is configured to reduce the speed of the trolley as said angle decreases.

4. A crane system according to claim 2 or 3, where said operating speed is configured to be proportional to the square root of the angle.

5. A crane system according to any preceding claim, where the datum (18) comprises the vertical direction.

6. A crane system according to any preceding claim, comprising an inverter to provide power to a motor (8) to drive the trolley and / or bridge member (4) to support the trolley in a horizontal direction in use, and where the controller (28) is configured to vary the frequency of the signal input to the inverter as a function of said angle.

7. A crane system according to any preceding claim, where the controller (28) is configured to move the trolley (7) and / or bridge (4) in a direction to reduce said angle.

8. A crane system according to claim 7, comprising a controller (14) having a manually operatable input, and where the user must activate the input during horizontal movement of the trolley (7) and / or bridge (4).

9. A crane system according to any preceding claim, where the angle measurement sensor (22,24) is configured to determine a real or virtual angle of the carrying member (10).

10. A crane system according to claim 9, where the sensor (24) comprises an optical, time-of-flight or radio-based system to determine the effective position the carrying member, a connector thereof or a load thereon to determine said virtual angle.

11. A crane system according to any preceding claim, comprising a sensor (26) to determine the effective length of the carrying member.

12. A crane system according to any preceding claim, where the trolley (7) is mounted to a bridge or gantry (4).

13. A crane system according to any preceding claim, where the trolley (7) is movable in two horizontal directions, and the controller (28) measures the angle of carrying member (10) in the respective dimensions.

14. A method of operating a crane system (2) comprising: providing a trolley (7) to support a load and movable about a horizontal direction to provide movement of the load in a horizontal direction accordingly; providing a carrying member (10) supported by the trolley (7) and configured to carrying the load in use; detecting an angle of the carrying member relative to a datum (18); controlling movement of the trolley (7) in use; and determining an operating speed of the trolley (7) when said angle is non-zero, and the where said operating speed is variable.

15. A computer program or computer readable medium comprising program instructions which, when executed by the computer, cause the computer to carry out a computer process implementing the method according to claim 14.

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