Crane and its control method

Abstract

To provide a crane and its control method capable of controlling a crane posture centered on a vertical direction.SOLUTION: A crane 1 comprises a position detection mechanism 13 to detect the position of the crane 1, and comprises an acquisition step in which a control mechanism acquires positional information of the crane 1 from the position detection mechanism 13, a determination step in which the control mechanism determines a correction value corresponding to the position of the crane 1 based on map information and positional information in which the correction value corresponding to the ratio of the traveling speed of a second traveling device 4b to the traveling speed of a first traveling device 4a is preset according to the position in the traveling direction y, and a determination step in which the control mechanism controls the traveling speed of the second traveling device 4b with respect to the traveling speed of the first traveling speed 4a based on the correction value.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a crane for loading and unloading containers and the like and a control method thereof, and more particularly to a crane capable of controlling the posture of the crane centered on the vertical direction and a control method thereof.

Background Art

[0002] Various quay cranes that travel on rails laid on a quay have been proposed (see, for example, Patent Document 1). The quay crane described in Patent Document 1 travels along a pair of rails laid at intervals in the traverse direction perpendicular to the traveling direction of the quay crane. This quay crane can suppress the swing of the boom by independently controlling the traveling speeds of the sea-side traveling device and the land-side traveling device.

[0003] Due to the influence of earthquakes, ground subsidence, etc., the interval in the traverse direction of a pair of rails laid on the quay (hereinafter sometimes referred to as the span) may change. In addition, the rails laid along the traveling direction may be curved in the traverse direction. Due to the change in the span and the curvature of the rails, the quay crane itself may tilt around the vertical direction.

[0004] When the quay crane tilts, a problem occurs in that the boom tilts with respect to the row of containers aligned with the container ship. In this case, the trolley that traverses along the boom moves deviated in the traveling direction with respect to the row of containers. It becomes difficult to position the crane during loading and unloading, and the loading and unloading efficiency of the quay crane may decrease.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a crane capable of controlling the posture of a crane centered in the vertical direction and a control method thereof.

Means for Solving the Problems

[0007] A control method for a crane for achieving the above object is a first traveling device and a second traveling device that are opposed to each other with a space therebetween in a lateral direction that crosses the traveling direction at a right angle, a structure supported by the first traveling device and the second traveling device, a horizontal member that forms a part of the structure and extends in the lateral direction, a trolley configured to be able to travel along the horizontal member, and a control mechanism that independently controls the traveling speeds of the first traveling device and the second traveling device. In the control method of the crane, a position detection mechanism for detecting the position of the crane and a posture measurement mechanism that measures the posture of the crane with the vertical direction as the central axis is provided in the crane, an acquisition step in which the control mechanism acquires the position information of the crane from the position detection mechanism, a correction value that is a ratio of the traveling speed of the second traveling device to the traveling speed of the first traveling device, map information preset according to the position in the traveling direction, and a determination step in which the control mechanism determines the correction value based on the position information, and based on the correction value, the control mechanism controls the traveling speed of the second traveling device with respect to the traveling speed of the first traveling device to perform execution step, a second acquisition step in which the control mechanism acquires the posture information of the crane from the posture measurement mechanism; a tilt calculation step in which the control mechanism calculates the tilt of the horizontal member with respect to the reference line based on the coordinate information of the reference line preset along the traveling direction and the posture information; and a correction step in which a correction value for correcting the correction value determined in the determination step is determined with the aim of making the tilt obtained in the tilt calculation step fall within a preset range, and the execution step has a configuration in which the control mechanism controls the traveling speed of the second traveling device based on the correction value corrected by the correction value characterized by this.

[0008] A crane for achieving the above object is a first traveling device and a second traveling device that are opposed to each other with a space therebetween in a lateral direction that crosses the traveling direction at a right angle, a structure supported by the first traveling device and the second traveling device, a horizontal member that forms a part of the structure and extends in the lateral direction, a trolley configured to be able to travel along the horizontal member, and a control mechanism that independently controls the traveling speeds of the first traveling device and the second traveling device. In the crane, a position detection mechanism for detecting the position of the crane and a posture measurement mechanism that measures the posture of the crane with the vertical direction as the central axisIt is provided, and the control mechanism determines a correction value, which is the ratio of the traveling speed of the second traveling device to the traveling speed of the first traveling device, based on map information preset according to the position in the traveling direction and the position information of the crane acquired from the position detection mechanism, and controls the traveling speed of the second traveling device with respect to the traveling speed of the first traveling device based on this correction value. having a configuration of , the control mechanism calculates the tilt of the horizontal member with respect to the reference line based on the coordinate information of the reference line preset along the traveling direction and the posture information of the crane acquired from the posture measurement mechanism, determines a correction value for correcting the correction value with the aim of making this tilt fall within a preset range, and has a configuration of controlling the traveling speed of the second traveling device based on the correction value corrected by the correction value It is characterized by this.

Effect of the Invention

[0009] According to the present invention, the traveling speed of the second traveling device with respect to the first traveling device can be controlled based on preset map information and the position information of the crane. Thereby, the attitude of the crane centered on the vertical direction can be controlled.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiment for Carrying Out the Invention

[0011] Hereinafter, a crane and its control method will be described based on the embodiments shown in the drawings. In the drawings, the traveling direction of the crane is indicated by arrow y, the transverse direction perpendicular to this traveling direction y is indicated by arrow x, and the vertical direction is indicated by arrow z.

[0012] As illustrated in FIGS. 1 and 2, the crane 1 is composed of a quay crane that travels along a pair of rails 3 laid on the quay wall 2. The pair of rails 3 extends along the traveling direction y. The pair of rails 3 is composed of a first rail 3a arranged on the sea side and a second rail 3b arranged on the land side. The first rail 3a and the second rail 3b are laid at a predetermined interval (hereinafter sometimes referred to as a span) in the transverse direction x.

[0013] The crane 1 includes a first traveling device 4a and a second traveling device 4b (hereinafter sometimes collectively referred to as the traveling device 4) that are opposed to each other at intervals in the transverse direction x, a structure 5 supported by the traveling device 4, a horizontal member 5a that constitutes a part of the structure 5, a trolley 6 configured to be able to travel along the horizontal member 5a, and a control mechanism 7 that controls the traveling device 4, the trolley 6, etc.

[0014] As illustrated in FIG. 2, in this embodiment, the crane 1 includes two first traveling devices 4a and two second traveling devices 4b. The first traveling device 4a travels on the first rail 3a, and the second traveling device 4b travels on the second rail 3b. The number of traveling devices 4 provided in the crane 1 is not limited to the above and can be appropriately changed according to the size, type, etc. of the crane 1.

[0015] The structure 5 is composed of a plurality of leg members supported by the traveling device 4, a plurality of beam members connecting the leg members, and diagonal members. The structure 5 has a horizontal member 5a extending in the traverse direction x. In this embodiment, the horizontal member 5a is composed of a girder supported by the leg members and extending in the traverse direction x, and a boom extending seaward from the seaward end of the girder. The trolley 6 transfers the container 8, which is a load, between the chassis 10 traveling on the quay wall 2 and the container ship 9 while traversing along the horizontal member 5a.

[0016] The control mechanism 7 is installed in the crane 1 as exemplified by the dashed line in FIG. 1. The installation location of the control mechanism 7 is not limited to the position exemplified in FIG. 1 and can be set at any position. The control mechanism 7 is composed of, for example, a PLC (Programmable Logic Controller) and an inverter that controls the voltage and current of the electricity supplied to motors such as the traveling device 4 and the trolley 6. The configuration of the control mechanism 7 is not limited to the above, and it is sufficient to have a configuration capable of independently controlling the traveling speeds of at least the first traveling device 4a and the second traveling device 4b. The control mechanism 7 may be composed of various known computers. The control mechanism 7 may have a central processing unit (CPU), a main memory unit (memory), an auxiliary storage unit (for example, HDD), an input unit (keyboard, mouse), and an output unit (display, printer).

[0017] The crane 1 is not limited to a quay crane. The crane 1 only needs to have a traveling device 4 and a horizontal member 5a, and is composed of, for example, a gantry crane that transfers containers while traveling in a container terminal. The crane 1 may also be composed of an overhead crane used in a factory or the like, a product crane arranged on the quay wall for shipping products such as steel plates, or an unloader arranged on the quay wall for loading and unloading bulk cargo such as coal.

[0018] As illustrated in Fig. 2, the crane 1 that performs the handling operation first travels along the rail 3 to position itself in the traveling direction y. Then, the trolley 6 travels horizontally along the horizontal member 5a and moves to directly above a predetermined container 8 that is loaded on the container ship 9 and is the target of the handling operation. The container 8 grasped by the lifting tool suspended from the trolley 6 is loaded onto the chassis 10 waiting at the quay 2. Also, the crane 1 may perform a handling operation of loading the container 8 carried in by the chassis 10 onto the container ship 9 in the reverse process as described above. If a difference is made in the traveling speeds of the first traveling device 4a and the second traveling device 4b, the crane 1 can tilt about the vertical direction z.

[0019] As illustrated in Fig. 3, one traveling device 4 has, for example, eight wheels 11 and four motors 12 that apply power to the wheels 11. The number of wheels 11 and motors 12 included in one traveling device 4 is not limited to the above and can be appropriately changed. The wheels 11 are configured to be able to contact the rail 3.

[0020] As illustrated in Fig. 4, the wheels 11 of the first traveling device 4a and the wheels 11 of the second traveling device 4b have a tread surface 11a configured to be able to contact the upper surface of the rail 3 and a flange 11b formed at one end of the tread surface 11a in the width direction that is parallel to the lateral direction x. By the flange 11b contacting the side surface of the rail 3, it is possible to suppress the derailment of the wheels 11 from the rail 3.

[0021] The length w1 of the tread surface 11a in the width direction is set to be 150% or more of the length w2 of the upper surface of the rail 3 in the width direction. The length w1 of the tread surface 11a is set within a range that satisfies w1 ≧ w2 * 150%.

[0022] Since the length w1 of the tread surface 11a is larger than the length w2 of the upper surface of the rail 3, the wheels 11 can tilt about the vertical direction z without derailing. In Fig. 4, the central axis when the wheels 11 tilt is shown by a two-dot chain line for explanation. With a configuration that enables the wheels 11 to tilt with respect to the rail 3, it becomes possible to tilt the crane 1 about the vertical direction z as the central axis. The posture of the crane 1 about the vertical direction z can be controlled.

[0023] Since the wheel 11 can tilt about the vertical direction z, it is possible to suppress the occurrence of distortion in the structure 5 of the crane 1. Conventionally, the length w1 of the tread surface 11a was set to be approximately the same as the length w2 of the upper surface of the rail 3. The position of the wheel 11 with respect to the rail 3 was fixed in the lateral direction x. Therefore, the flange 11b of the wheel 11 contacted the rail 3, and the tilting of the wheel 11 was suppressed, resulting in distortion in the structure 5. In the embodiment illustrated in FIG. 4, the wheel 11 is configured to be movable with respect to the rail 3 in the lateral direction x. When distortion occurs in the structure 5, this distortion is eliminated by the tilting of the wheel 11 with respect to the rail 3. It is possible to suppress the swinging of the container 8 lifted by the structure 5 and the horizontal members 5a such as the boom that form part of the structure 5.

[0024] The crane 1 can travel even if the span, which is the length between the first rail 3a and the second rail 3b in the lateral direction x, changes. Even if the rail 3 curves or the span changes due to the settlement or deformation of the quay wall 2, it is possible to make the crane 1 travel. Specifically, for example, even if the span of the pair of rails 3a and 3b widens, since the length w1 of the tread surface 11a of the wheel 11 is set to be relatively large, the crane 1 can travel without derailing. Also, the flange 11b is not pressed tightly against the side surface of the rail 3, and there is no adverse effect on the travel of the crane 1.

[0025] The configuration of the wheel 11 is not limited to the above. The wheel 11 may have flanges 11b formed on both sides of the tread surface 11a, or may be composed only of the tread surface 11a without the flanges 11b. A configuration in which the flange 11b is formed only on one side rather than on both sides of the tread surface 11a makes it more difficult for the flange 11b to contact the rail 3. This is advantageous for increasing the range in which the crane 1 tilts about the vertical direction z.

[0026] The control method of the crane 1 will be described with reference to the flowchart illustrated in FIG. 5. When the control mechanism 7 of the crane 1 starts control (start), first, in the acquisition step S1, the control mechanism 7 acquires the position information P1 of the crane 1 from the position detection mechanism 13. As illustrated in FIG. 6, the position detection mechanism 13 is composed of, for example, a global navigation satellite system (GNSS) antenna installed on the crane 1. In this case, the control mechanism 7 acquires the longitude and latitude of the crane 1 as the position information P1.

[0027] In the next determination step S2, the control mechanism 7 determines the correction value P2 corresponding to the position of the crane 1 based on the map information P3 preset according to the position in the traveling direction y and the position information P1, where the correction value P2 is the ratio of the traveling speed of the second traveling device 4b to the traveling speed of the first traveling device 4a.

[0028] As illustrated in FIG. 7, the map information P3 is composed of a plurality of preset sections F along the traveling direction y and the correction value P2 preset for each of the plurality of sections F. In this embodiment, the correction value P2 is set as a value for determining the traveling speed of the second traveling device 4b based on the traveling speed of the first traveling device 4a. The correction value P2 is not limited to this configuration, and may have a configuration that defines the speed difference between the traveling speed of the first traveling device 4a and the traveling speed of the second traveling device 4b.

[0029] The section F is set within a range of coordinates (x, y) such as longitude and latitude, for example. The section F may be set with coordinates in a coordinate system preset on the quay wall 2. As illustrated in FIG. 6, the sections F1-5 may be set according to the curvature of the rail 3 and the change in the span. In FIG. 6, the boundary lines of the sections F1-5 are shown as dashed-dotted lines for the sake of explanation. The plurality of sections F may be set at equal intervals along the traveling direction y.

[0030] In the determination step S2, a correction value P2 corresponding to the section F where the crane 1 is located is determined by the control mechanism 7. Therefore, the position detection mechanism 13 only needs to be configured to be able to detect in which section F the crane 1 is located. For example, the position detection mechanism 13 may be configured by a transponder or a sensor installed on the rail.

[0031] The map information P3 is stored in an external device and has a configuration of being read from this device by the control mechanism 7. The map information P3 may be stored in the auxiliary storage unit provided in the control mechanism 7.

[0032] In the execution step S3 illustrated in FIG. 5, based on the correction value P2 determined in the determination step S2, the running speed of the second traveling device 4b with respect to the running speed of the first traveling device 4a is controlled by the control mechanism 7. Specifically, the control mechanism 7 adjusts the voltage and current of the electricity supplied to the traveling device 4 by an inverter.

[0033] The processes from the acquisition step S1 to the execution step S3 are repeated (return) according to the running of the crane 1. Taking the processes from the acquisition step S1 to the execution step S3 as one cycle, this cycle is repeated at a predetermined time interval. The cycle is repeatedly executed at a predetermined time interval such as 10 sec or 20 sec, for example. The time interval at which the cycle is repeated is not limited to the above and is appropriately set according to the running speed of the crane 1 and the size of the section F in the running direction y.

[0034] Taking the case of running the crane 1 illustrated in FIG. 6 toward the right as an example, a specific example of the control method of the crane 1 will be described. The running direction (right or left in FIG. 6) and running speed of the crane 1 are determined by the operation of the operator's master controller. The crane 1 may be configured as an unmanned crane automatically controlled in addition to a manned crane by the operator.

[0035] The control mechanism 7 acquires, as the position information P1, that the position of the crane 1 is the section F1 in the acquisition step S1. The control mechanism 7 determines ±0% as the correction value P2 corresponding to the section F1 in the determination step S2.

[0036] The traveling speed of Crane 1 is determined in proportion to the angle at which it knocks down the mast cone. Hereinafter, the traveling speed at full throttle of the mast cone is set as index 100, and the traveling speed at half throttle is set as index 50. When full throttle is input from the mast cone of Crane 1, in section F1, both the first traveling device 4a and the second traveling device 4b travel at a traveling speed of index 100. Since the correction value P2 corresponding to section F1 is ±0%, the first traveling device 4a and the second traveling device 4b travel at the same traveling speed.

[0037] While Crane 1 is traveling in section F1, the cycle from acquisition step S1 to execution step S3 illustrated in FIG. 5 is repeatedly executed. Unless the correction value P2 determined in determination step S2 is changed, the speed difference between the first traveling device 4a and the second traveling device 4b controlled in execution step S3 remains unchanged.

[0038] When Crane 1 reaches section F2, the correction value P2 becomes -2%. When the first traveling device 4a is at a traveling speed of index 100, the second traveling device 4b becomes 100*(100% - 2%) = 98 and travels at a traveling speed of index 98. Since the second traveling device 4b arranged on the land side becomes slower than the first traveling device 4a arranged on the sea side, the sea-side end of the horizontal member 5a of Crane 1 tilts forward (right side in FIG. 6).

[0039] When the speed input from the mast cone is index 50, the first traveling device 4a becomes at a traveling speed of index 50, and the second traveling device 4b becomes 50*(100% - 2%) = 49 and travels at a traveling speed of index 49.

[0040] As illustrated in FIG. 2, since the rail 3 is curved in section F2, if the first traveling device 4a and the second traveling device 4b are made to travel at the same speed, as shown by the dashed line, the sea-side end of the horizontal member 5a tilts backward (left side in FIG. 2). On the other hand, when control using the correction value P2 is performed, as shown by the dashed line in FIG. 6, this tilt of Crane 1 can be suppressed.

[0041] It is desirable that the cycle consisting of the acquisition step S1, the determination step S2, and the execution step S3 be configured as feedforward control. In this case, when determining the correction value P2 in the determination step S2, the correction value P2 is determined based on the section F that is predicted to be reached when the next cycle is executed.

[0042] Specifically, when it is predicted that the position information P1 acquired in the next cycle will be the section F2, the correction value P2 corresponding to the section F2 in the current cycle is determined in the determination step S2. That is, the traveling speed of the traveling device 4 is controlled based on the correction value P2 corresponding to the section F2 at the timing immediately before or almost simultaneously when the crane 1 enters from the section F1 into the section F2.

[0043] Since the control mechanism 7 controls the traveling speed of the crane 1, it is easy to predict the position of the crane 1 from this traveling speed and the position information P1 acquired in the acquisition step S1. For example, the timing at which the crane 1 enters the section F2 can be predicted from the time when it enters the section F1 and the current traveling speed of the crane 1.

[0044] Since the control corresponding to the section F2 can be executed before the crane 1 enters the section F2, the control illustrated in FIG. 5 is feedforward control. Before the crane 1 loses its posture due to the influence of the curvature of the rail 3 or the like, the traveling speed of the traveling device 4 can be controlled to control the posture of the crane 1. Even when the traveling speed of the crane 1 is relatively high or the influence of the curvature of the rail 3 or the like is relatively large, it becomes easier to control the posture of the crane 1.

[0045] The cycle consisting of the acquisition step S1, the determination step S2, and the execution step S3 may be configured as feedback control. In this case, the correction value P2 corresponding to the section F where the crane 1 is located in the current cycle is determined in the determination step S2. When the traveling speed of the crane 1 is relatively low or the influence of the curvature of the rail 3 or the like is relatively small, the posture of the crane 1 can be sufficiently controlled.

[0046] Regardless of whether the control illustrated in FIG. 5 is feedforward control or feedback control, the control mechanism 7 is configured to determine the correction value P2 based on the map information P3 and the position information P1.

[0047] When the crane 1 reaches the section F3, the correction value P2 becomes ±0%. Both the first traveling device 4a and the second traveling device 4b travel at a traveling speed of index 100.

[0048] When the crane 1 reaches the section F4, the correction value P2 becomes +2%. When the first traveling device 4a is at a traveling speed of index 100, the second traveling device 4b becomes 100*(100% + 2%) = 102 and travels at a traveling speed of index 102. The sea - side end of the horizontal member 5a of the crane 1 tilts backward (left side in FIG. 6).

[0049] As illustrated in FIG. 2, in the section F4, since the rail 3 is curved, if the first traveling device 4a and the second traveling device 4b are made to travel at the same speed, the sea - side end of the horizontal member 5a will tilt forward (right side in FIG. 2). On the other hand, when control using the correction value P2 is performed, as shown by the dashed line in FIG. 6, this tilt of the crane 1 can be suppressed.

[0050] When the crane 1 reaches the section F5, the correction value P2 becomes - 1%. When the first traveling device 4a is at a traveling speed of index 100, the second traveling device 4b travels at a traveling speed of index 99. As illustrated in FIG. 2, in the section F5, since the first rail 3a is inclined in the direction where the span widens, if the first traveling device 4a and the second traveling device 4b are made to travel at the same speed, the sea - side end of the horizontal member 5a will tilt backward (left side in FIG. 2). On the other hand, when control using the correction value P2 is performed, as shown by the dashed line in FIG. 6, this tilt of the crane 1 can be suppressed.

[0051] Based on the position information P1 and the map information P3, the crane 1 can control the traveling speed of the second traveling device 4b with respect to the first traveling device 4a. Since the posture of the crane 1 centered on the vertical direction z can be controlled, the posture of the crane 1 in a predetermined section F can be set to a preset posture. For example, as illustrated in FIG. 6, the crane 1 can travel while maintaining the state where the horizontal member 5a is orthogonal to the straight line of the edge 2a of the quay wall 2. When the posture of the crane 1 is controlled by feedforward control, it is also possible to continuously maintain the state where the horizontal member 5a is orthogonal to the straight line of the edge 2a without disturbing it.

[0052] It is possible to move the horizontal member 5a in a state orthogonal to the longitudinal direction of the container 8 with respect to the container 8 arranged on the container ship 9. The containers 8 on the container ship 9 are placed in a state where the longitudinal direction is parallel to the traveling direction y and the short side direction is parallel to the traversing direction x. Even when the rail 3 is curved, the crane 1 can travel while keeping the posture of the crane 1 with respect to the longitudinal direction of the container 8 constant. The alignment of the crane 1 with respect to the container 8 becomes easy.

[0053] As shown by the dashed line in FIG. 2, when the horizontal member 5a of the crane 1 is tilted with respect to the longitudinal direction of the container 8, when loading and unloading a row of containers 8 arranged along the traversing direction x in the container ship 9, it becomes impossible to perform the loading and unloading without moving the crane 1 halfway. The crane 1 can avoid such a state where the loading and unloading efficiency is significantly reduced, as illustrated in FIG. 6.

[0054] In the foregoing embodiment, the traveling speed of the first traveling device 4a is determined based on the speed command input from the master controller, and the traveling speed of the second traveling device 4b is determined based on the traveling speed of the first traveling device 4a and the correction value P2. The present invention is not limited to this configuration. A configuration may be adopted in which the traveling speeds of the first traveling device 4a and the second traveling device 4b are respectively determined based on the speed command input from the master controller and the correction value P2. For example, when the correction value P2 is +2% and the speed command input from the master controller is an index of 100, the traveling speed of the second traveling device 4b may be set as the index 100, and the traveling speed of the first traveling device 4a may be set as 100 / (100% + 2%) = 98.04.

[0055] In the foregoing embodiment, the first traveling device 4a is arranged on the sea side, and the second traveling device 4b is arranged on the land side. The present invention is not limited to this configuration. The first traveling device 4a may be arranged on the land side, and the second traveling device 4b may be arranged on the sea side.

[0056] When setting the section F of the map information P3, the survey of the rail 3 may be performed in advance, and the section F may be set in a state of distinguishing between the portion where the rail 3 is parallel to the edge 2a of the quay wall 2 and other portions where the rail 3 is curved, for example. At this time, the section F may not be equally spaced along the traveling direction y.

[0057] The correction value P2 of the map information P3 can be set in advance, for example, from the inclination of the rail 3 with respect to the edge 2a of the quay wall 2. The greater the inclination of the rail 3 with respect to the edge 2a, the greater the inclination of the crane 1 about the vertical direction z. By setting the correction value P2 according to the magnitude of the inclination of the rail 3, the crane 1 can travel in a state of being apparently parallel to the edge 2a of the quay wall 2.

[0058] Further, for example, the correction value P2 may be set in advance from the inclination of the horizontal member 5a with respect to the edge 2a when the first traveling device 4a and the second traveling device 4b are traveling at the same traveling speed. The speed difference of the traveling device 4 required to eliminate the inclination of the horizontal member 5a can be set as the correction value P2. The correction value P2 may also be set from the inclination of the horizontal member 5a and the magnitude of the span.

[0059] Referring to the flowchart illustrated in FIG. 8 and the block diagram illustrated in FIG. 9, a modification of the control method of the crane 1 will be described. First, a cycle consisting of an acquisition step S1, a determination step S2, and an execution step S3 is repeated to control the attitude of the crane 1 by the feedforward control 15. The content of this feedforward control 15 is the same as that of the embodiment illustrated in FIG. 5. In this embodiment, the feedback control 16 is combined with the feedforward control 15. As illustrated in FIG. 8, the feedback control 16 has a second acquisition step S4, an inclination calculation step S5, and a correction step S6. In FIG. 8, for the sake of explanation, the ranges of the feedforward control 15 and the feedback control 16 are shown surrounded by a dashed line.

[0060] In the second acquisition step S4, the control mechanism 7 acquires the attitude information P4 of the crane 1 from the attitude measurement mechanism 14. As illustrated in FIG. 10, the attitude measurement mechanism 14 is composed of, for example, two GNSS antennas installed at intervals in the lateral direction x on the horizontal member 5a of the crane 1. In this case, the control mechanism 7 acquires the longitude and latitude from each of the two antennas. The straight line connecting the coordinates of the two antennas is acquired by the control mechanism 7 as the attitude information P4 indicating the extending direction of the horizontal member 5a. The attitude measurement mechanism 14 only needs to have a configuration capable of acquiring the inclination of the crane 1 centered on the vertical direction z. When the attitude measurement mechanism 14 is composed of a GNSS antenna, this antenna may be shared as the position detection mechanism 13. That is, devices such as GNSS antennas installed on the crane 1 may be used as the position detection mechanism 13 and the attitude measurement mechanism 14.

[0061] In the next inclination calculation step S5, the control mechanism 7 calculates the inclination θ of the horizontal member 5a with respect to the reference line L based on the coordinate information P5 of the reference line L preset along the traveling direction y and the attitude information P4.

[0062] As illustrated in FIG. 10, the reference line L is composed of a single straight line parallel to the traveling direction y. The reference line L is preset based on, for example, the extending direction of the rail 3, the extending direction of the edge 2a of the quay wall 2, or the extending direction of the center line connecting the bow and the stern of the container ship 9. When the reference line L is set based on the extending direction of the rail 3, the first rail 3a or the second rail 3b is cut out in a range of, for example, 300 m in the traveling direction y, and the straight line when approximating this first rail 3a or the second rail 3b with a single straight line extending in the traveling direction y is set as the reference line L. When the reference line L is set based on the extending direction of the edge 2a of the quay wall 2, the straight line when approximating the edge 2a cut out in a predetermined range in the same manner as in the case of the rail 3 with a single straight line is set as the reference line L.

[0063] When the reference line L is set based on the extending direction of the center line of the container ship 9, when the container ship 9 docks at the quay wall 2, the position of this container ship 9 is measured, and the reference line L is set based on this measurement result. Each time the container ship 9 docks, the reference line L is set. In FIG. 10, the reference line L set based on the container ship 9 is shown by a two-dot chain line for the sake of explanation. As illustrated in FIG. 10, in a plan view, the angle formed by the linearly set reference line L and the horizontal member 5a is the inclination θ.

[0064] The measurement of the position of the container ship 9 may be performed by surveying or the like, or may be performed by a camera or a laser scanner installed on the quay crane. When the reference line L is set based on the center line of the container ship 9, even when the center line of the container ship 9 is inclined with respect to the edge 2a of the quay wall 2, the crane 1 can perform the cargo handling operation efficiently.

[0065] In order to improve the cargo handling efficiency of the container 8, ultimately, the horizontal member 5a such as the boom needs to be orthogonal to the longitudinal direction of the container 8. Therefore, the reference line L may be set based on the longitudinal direction of the placed container 8.

[0066] In the correction step S6 illustrated in FIG. 8, the control mechanism 7 determines a correction value P6 for correcting the correction value P2 determined in the determination step S2, with the target being a state where the inclination θ of the horizontal member 5a with respect to the reference line L is within a preset range. That is, in the correction step S6, a correction value P6 for correcting the correction value P2 is determined. This correction value P6 is a value for correcting the correction value P2 so that the inclination θ is within the preset range. The range of the inclination θ is set, for example, to 90° ± 0.1°. When the span, which is the length between the first traveling device 4a and the second traveling device 4b of the crane 1, is 30 m and the outreach, which is the length from the first traveling device 4a to the sea side end of the horizontal member 5a, is 70 m, the turning radius of the sea side end of the horizontal member 5a centered on the vertical direction z is 70 m + 30 m / 2 = 85 m. When the range of the inclination θ is 90° ± 0.1°, the sea side end of the horizontal member 5a is within a range of ±150 mm in the traveling direction y. A range of ±150 mm is an acceptable range when the trolley 6 grasps the container 8.

[0067] The range of the inclination θ is not limited to the above. It can be appropriately set within a range that has no influence on the handling according to the size, type of the crane 1, and type of the load.

[0068] As illustrated in FIG. 8, while the feedforward control 15 is repeatedly executed in accordance with the traveling of the crane 1, a cycle consisting of a second acquisition step S4, an inclination calculation step S5, and a correction step S6 is repeatedly executed. The cycle from the second acquisition step S4 to the correction step S6 becomes feedback control 16 for correcting the correction value P2 according to the inclination θ that changes as the crane 1 travels. The cycle from the second acquisition step S4 to the correction step S6 is repeatedly executed at a predetermined time interval such as 5 seconds or 10 seconds. The feedforward control 15 and the feedback control 16 are executed in parallel. It is not necessary to match the cycle of the feedback control 16 with the cycle of the feedforward control 15. For example, the feedforward control 15 may be executed at a time interval of 10 seconds, and the feedback control 16 may be executed at a time interval of 5 seconds. The time interval at which the cycle of the feedback control 16 is repeated is not limited to the above and can be set as appropriate. The smaller the time interval at which the feedback control 16 is executed, the easier it is to maintain the crane 1 in a predetermined posture.

[0069] As illustrated in FIG. 9, the correction value P2 determined in the feedforward control 15 is corrected by the correction value P6 determined by the feedback control 16. Based on the corrected correction value P2' corrected by the correction value P6, the traveling speed of the second traveling device 4b is controlled by the control mechanism 7.

[0070] Taking as an example the case where the crane 1 illustrated in FIG. 10 travels toward the right, a specific example of the control method of the crane 1 will be described. The crane 1 travels while performing feedforward control 15. At this time, the attitude measurement mechanism 14 acquires attitude information P4 at a predetermined time interval. The control mechanism 7 calculates the inclination θ of the horizontal member 5a with respect to the reference line L based on the acquired attitude information P4. A correction value P6 for correcting the correction value P2 is determined with the target being a state where this inclination θ falls within a predetermined range, for example, 90° ± 0.1°. In the correction step S6, when the inclination θ is greater than the predetermined range, that is, when the sea-side end of the horizontal member 5a inclines forward (right side in FIG. 10), a correction value P6 such as +1% is determined. When the correction value P2 determined in the determination step S2 is +2%, it is corrected to +2% + 1% = +3%. In the execution step S3, the traveling speed of the traveling device 4 is controlled based on the corrected correction value P2' which is +3%. Similarly, when the correction value P2 is, for example, -2%, it is corrected to -2% + 1% = +1%. In the execution step S3, the traveling speed of the traveling device 4 is controlled based on the corrected correction value P2' which is +1%. When the inclination θ is smaller than the predetermined range, a correction value P6 such as -1% is determined.

[0071] In the execution step S3, the traveling speed of the traveling device 4 is controlled based on the value obtained by adding together the correction value P2 determined in the determination step S2 and the correction value P6 determined in the correction step S6. It is desirable to set the absolute value of the correction value P6 determined in the correction step S6 to be larger as the difference between the value of the inclination θ obtained in the inclination calculation step S5 and the preset range is larger. This makes it possible to bring the inclination θ closer to the target range in a short time.

[0072] By performing feedback control 16 that determines the correction value P6 based on the attitude information P4 of the crane 1, the attitude of the crane 1 can be accurately controlled. If the feedforward control 15 is being executed, for example, the state where the horizontal member 5a is orthogonal to the edge 2a of the quay wall 2 is basically maintained. There may be slippage of the wheels 11 or the crane 1 may tilt about the vertical direction z due to strong winds. This tilt can be eliminated by the feedback control 16 illustrated in FIG. 8. With the feedback control 16, the crane 1 can maintain a preset attitude even if there are disturbances such as slippage of the wheels 11. Also, when the curvature of the rail 3 or the like changes due to aging, the attitude of the crane 1 can be controlled in a state corresponding to this change.

[0073] Note that the period from the acquisition step S1 to the execution step S3 may be a configuration that controls the attitude of the crane 1 by feedback control. The feedback control with the period from the acquisition step S1 to the execution step S3 can be combined with the feedback control 16 illustrated in FIG. 8. Even when the two feedback controls are combined, an effect similar to the above can be obtained.

[0074] The control mechanism 7 may have a configuration that performs a rewriting step. In the rewriting step, based on the correction value P6 obtained in the correction step S6, the control mechanism 7 rewrites the correction value P2 of the map information P3. The correction value P2 of the map information P3 is rewritten to the corrected correction value P2'. For example, the control mechanism 7 may have a configuration that rewrites the correction value P2 stored in the map information P3 to the corrected correction value P2' each time the correction value P6 is acquired from the correction step S6.

[0075] As the crane 1 travels, the correction value P2 of the map information P3 is rewritten to the corrected correction value P2'. Since the correction value P2 continues to be updated to be able to cope with even minute changes in the rail 3, it is advantageous for improving the accuracy of the feedforward control. When the reference line L is set based on the container ship 9, the map information P3 is rewritten to the correction value P2' corresponding to this container ship 9. Therefore, the crane 1 can execute the feedforward control 15 based on the appropriate correction value P2.

[0076] The control mechanism 7 may have a configuration in which the correction value P6 is accumulated for each section F, and the correction value P2 of the map information P3 is rewritten based on a plurality of correction values P6 corresponding to a predetermined section F. When the correction value P6 is accumulated for each section F and a predetermined number of correction values P6 are gathered, for example, the control mechanism 7 rewrites the correction value P2 of the map information P3 based on the average value of this correction value P6.

[0077] When the crane 1 is made to travel, the correction value P6 is obtained for each section F by the correction step S6. This correction value P6 is stored, for example, in the auxiliary storage unit of the control mechanism 7. When the correction value P2 is repeatedly corrected in a predetermined section F, the correction value P2 set in the map information P3 may not be appropriate.

[0078] For example, when the correction values P6 in the section F2 are +1%, -1%, ±0%, -1%, -1%, the average value of the correction values P6 is -0.4%. In this case, in the rewriting step, the correction value P2 of the section F2 is rewritten from -2% to -2.4%.

[0079] Even when there are aging changes such as the curvature of the rail 3 and the change in the span, the map information P3 corresponding to this can be obtained. The correction value P2 of the map information P3 is rewritten to a highly accurate value according to the travel of the crane 1. The more the crane 1 travels along with the cargo handling operation, the more it can perform highly accurate feedforward control 15.

[0080] Due to the influence of wind and rain, the correction value P6 may become a large value due to the unintended slipping of the wheel 11, etc. For example, the correction value P6 may be +4% or -8%. In order to exclude such values, for example, when the correction value P6 exceeds a predetermined range such as ±2%, a configuration may be adopted in which the rewriting step is not performed. Hereinafter, this control may be referred to as filter control.

[0081] With a configuration that performs filter control, factors based on the curvature of the rail 3 and changes in the ground are reflected in the corrected correction value P2', and it becomes difficult for factors based on sudden events such as typhoons and earthquakes to be reflected in the corrected correction value P2'. This is advantageous for obtaining the map information P3 for performing high-precision feedforward control 15.

[0082] The map information P3 may be created using the rewriting step. For example, with all the correction values P2 of the initial map information P3 set to ±0%, the traveling of the crane 1 is repeated. The correction value P6 is obtained in the correction step S6. In the rewriting step, the map information P3 is created by rewriting the correction value P2 of the initial map information P3 based on the correction value P6. Thereafter, the map information P3 may be appropriately updated using the rewriting step.

[0083] With a configuration that creates the map information P3 using the rewriting step, prior work such as surveying for creating the map information P3 becomes unnecessary.

[0084] Multiple cranes 1 are often arranged on the quay wall 2. A plurality of cranes 1 traveling on the same rail 3 may have a configuration that shares the map information P3. Also, the map information P3 updated by the rewriting step may be shared by a plurality of cranes 1. The crane 1 may have a configuration that transmits the map information P3 updated by the rewriting step to other cranes 1 traveling on the same rail 3.

[0085] As illustrated in FIG. 11, even when the container ship 9 is moored in an inclined state with respect to the edge 2a of the quay wall 2, the crane 1 can efficiently perform cargo handling operations. When map information P3 corresponding to the inclined container ship 9 is preset, the crane 1 can travel along the rail 3 while maintaining the state where the horizontal member 5a of the crane 1 is orthogonal to the longitudinal direction of the container 8. Alternatively, a reference line L corresponding to the center line of the inclined container ship 9 may be set, and feedback control 16 and a rewriting step may be executed to update the map information P3. After the map information P3 is updated, the crane 1 can travel while maintaining a posture suitable for the container 8. In FIG. 11, for the sake of explanation, the postures of the crane 1 in each section F are shown by dashed lines.

[0086] The crane 1 can travel while maintaining an arbitrary posture with respect to the cargo to be handled. This is advantageous for improving the cargo handling efficiency of the crane 1.

[0087] The crane and its control method of the present invention are not limited to the crane traveling on the rail 3, but can also be applied to a tire-type crane. It becomes possible to control the posture of the crane in response to the inclination and unevenness of the traveling surface with which the tires come into contact.

Explanation of Reference Numerals

[0088] 1 Crane 2 Quay wall 3 Rail 3a First rail 3b Second rail 4 Traveling device 4a First traveling device 4b Second traveling device 5 Structure 5a Horizontal member 6 Trolley 7 Control mechanism 8 Container 9 Container ship 10 Chassis 11 Wheel 11a Tread 11b Flange 12 Motor 13 Position Detection Mechanism 14 Posture Measurement Mechanism 15 Feedforward Control 16 Feedback Control w1 (Length of the tread surface) w2 (Length of the rail) P1 Position Information P2 Correction Value P2' Corrected Correction Value P3 Map Information P4 Posture Information P5 Coordinate Information P6 Correction Value F1 - 5 Section S1 Acquisition Step S2 Decision Step S3 Execution Step S4 Second Acquisition Step S5 Slope Calculation Step S6 Correction Step L Reference Line x Transverse Direction y Travel Direction z Vertical Direction

Claims

1. A first traveling device and a second traveling device that are opposed to each other at intervals in the lateral direction perpendicular to the traveling direction, a structure supported by the first traveling device and the second traveling device, a horizontal member that forms a part of the structure and extends in the lateral direction, a trolley configured to be able to travel along the horizontal member, and a control mechanism for independently controlling the traveling speeds of the first traveling device and the second traveling device. In the control method of the crane, The crane is provided with a position detection mechanism for detecting the position of the crane and an attitude measurement mechanism for measuring the attitude of the crane with the vertical direction as the central axis, An acquisition step in which the control mechanism acquires the position information of the crane from the position detection mechanism, A determination step in which the control mechanism determines the correction value based on the map information in which the correction value, which is the ratio of the traveling speed of the second traveling device to the traveling speed of the first traveling device, is preset according to the position in the traveling direction and the position information, An execution step in which the control mechanism controls the traveling speed of the second traveling device with respect to the traveling speed of the first traveling device based on the correction value, A second acquisition step in which the control mechanism acquires the attitude information of the crane from the attitude measurement mechanism, An inclination calculation step in which the control mechanism calculates the inclination of the horizontal member with respect to the reference line based on the coordinate information of the reference line preset along the traveling direction and the attitude information, A correction step of determining a correction value for correcting the correction value determined in the determination step with the state that the inclination obtained in the inclination calculation step is within a preset range as the target, The execution step has a configuration in which the control mechanism controls the traveling speed of the second traveling device based on the correction value corrected by the correction value. A control method for a crane, characterized in that.

2. The control method for a crane according to claim 1, further comprising a rewriting step in which the control mechanism rewrites the correction value in the map information based on the correction value obtained in the correction step.

3. A crane comprising: a first traveling device and a second traveling device that are opposed to each other with a space therebetween in a transverse direction that crosses the traveling direction at a right angle; a structure supported by the first traveling device and the second traveling device; a horizontal member that forms a part of the structure and extends in the transverse direction; a trolley configured to be able to travel along the horizontal member; and a control mechanism that independently controls the traveling speeds of the first traveling device and the second traveling device. The crane further comprises a position detection mechanism that detects the position of the crane, and an attitude measurement mechanism that measures the attitude of the crane with the vertical direction as the central axis. The control mechanism determines the correction value based on map information in which a correction value, which is the ratio of the traveling speed of the second traveling device to the traveling speed of the first traveling device, is preset according to the position in the traveling direction, and the position information of the crane acquired from the position detection mechanism, and controls the traveling speed of the second traveling device with respect to the traveling speed of the first traveling device based on this correction value. The control mechanism calculates the inclination of the horizontal member with respect to the reference line based on the coordinate information of the reference line preset along the traveling direction and the attitude information of the crane acquired from the attitude measurement mechanism, determines a correction value for correcting the correction value with the goal of bringing the inclination within a preset range, and controls the traveling speed of the second traveling device based on the correction value corrected by the correction value. A crane characterized by having such a configuration.

4. The first traveling device and the second traveling device each have a plurality of wheels configured to be able to contact a rail extending along the traveling direction. The wheel has a tread surface configured to be able to contact the upper surface of the rail, and the tread surface has a length that is 150% or more of the length of the upper surface of the rail in the width direction orthogonal to the extending direction of the rail. The crane according to claim 3.

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