JP6407903B2 - Crane and crane control method - Google Patents

Description

  The present invention relates to a crane having a traveling device and a crane structure supported by the traveling device that are opposed to each other in the transverse direction. Specifically, the crane structure is deformed when the crane travels and stops. The present invention relates to a crane that can suppress vibration.

  Quay cranes are used as cargo handling equipment for cargo handling such as containers in harbors. The quay crane includes a traveling device that is opposed in the transverse direction (also referred to as the sea-land direction) that is a horizontal direction orthogonal to the traveling direction along the quay, and a crane structure that is supported by the traveling device. And a boom that is supported by the crane structure and extends in the transverse direction. The traveling device includes a seaside traveling device disposed on the sea side and a landside traveling device disposed on the land side.

  The sea-side traveling device and the land-side traveling device are each a traveling wheel, a motor that transmits power to the traveling wheel, an inverter that is connected to the motor and controls the rotational speed (rotation speed) of the motor, and the inverter And a controller for giving a command of the rotational speed to the motor.

  The controller is installed, for example, in a cab of a crane, and gives a speed command to each inverter by the operation of the driver. The inverter supplies electricity with the frequency and voltage adjusted based on the speed command to the motor. That is, the sea-side traveling device and the land-side traveling device are controlled independently.

  When the typhoon approaches, in order to fix the quay crane to the quay, anchor pins are inserted into through holes formed in the traveling device and the quay, respectively. At this time, the sea-side traveling device and the land-side traveling device are controlled independently so that the sea-side traveling device and the quay through-hole can be aligned, and the land-side traveling device and the quay through-hole can be aligned. It is configured to be able to.

  When unloading a container with a quay crane, the driver moves the quay crane in the traveling direction to align the center of the boom with the center of the container to be loaded. When traveling the quay crane, the driver operates each controller so that the sea-side traveling device and the land-side traveling device travel in the same direction at the same speed.

  When stopping the quay crane, first, for example, the motor is slowly decelerated to 2% with respect to 100% of the rated rotational speed of the motor, and then the brake device installed in the traveling device is operated to stop the traveling device. If the motor speed is reduced to 0% of the rated rotation speed, that is, 0 rpm, the quay crane may be pushed and moved by wind or the like. Conventionally, the brake is applied before the traveling device stops completely. It was.

  Since the quay crane has a boom protruding to the sea side, the center of gravity of the quay crane is biased to the sea side, and the load that the sea side traveling device should support compared to the land side traveling device (hereinafter, (Sometimes called wheel load). Since the wheel load of the sea-side travel device is larger, even if a speed command is given from the controller so that the sea-side travel device and the land-side travel device travel at the same speed, the sea-side travel is relatively large. Applicants have discovered that a delay occurs in the device.

When the quay crane is caused to travel, the land-side traveling device is moved forward than the sea-side traveling device, that is, the position of each traveling device is shifted in the traveling direction. Due to the shift in the traveling direction between the sea-side traveling device and the land-side traveling device, a rotational moment about the vertical direction is generated in the crane structure, and the crane structure is distorted (deformed). In addition, a rotational moment in the direction opposite to the above is generated in the crane structure as a force in a direction to release this strain. Due to this rotational moment, the crane structure is vibrated, which causes a problem that the boom tip swings in the traveling direction.

  Moreover, when stopping the traveling device by applying a brake, the sea-side traveling device and the land-side traveling device are shifted in the traveling direction, so that the residual strain remains in the crane structure. The position of the traveling device is fixed. Due to the influence of this distortion, vibration is generated in the crane structure after braking, and this vibration causes a problem that the boom tip swings in the traveling direction.

  The boom of a quay crane is formed by a single columnar member in addition to a twin box structure in which two columnar members extending in the transverse direction are connected by a steel material extending in the traveling direction to form a frame structure. There is a mono box structure. The mono box structure boom is lighter than the twin box structure boom, but the boom tip is easy to swing because the rigidity against the swing in the traveling direction is relatively small.

  In the state where the boom tip is oscillating, the positioning with respect to the container to be handled cannot be performed. Therefore, conventionally, it has been necessary to wait until the boom tip oscillates. This waiting time was necessary each time the quay cranes traveled and stopped.

  The applicant has already proposed a damping structure that suppresses the swing of the boom of the quay crane (see, for example, Patent Document 1). Patent Document 1 proposes a configuration in which vibration suppression masses are installed at the sea side end of the boom and the land side end of the girder to suppress the boom swing that occurs during an earthquake. Although this vibration control mass can attenuate the boom swing that occurs when the quay crane is running and stopped, the boom swing itself cannot be prevented, so a waiting time is still necessary.

JP 2011-213455 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a crane capable of suppressing the deformation and vibration of the crane structure when the crane is running and stopped.

A crane of the present invention that achieves the above object includes a traveling device that is opposed to each other in a transverse direction that intersects the traveling direction, and a crane structure that is supported by the traveling device, Each of the traveling devices includes a traveling wheel, a motor that transmits power to the traveling wheel, an inverter that is connected to the motor and controls the rotational speed of the motor, and a rotational speed command to the motor via the inverter. Each of the inverters has a torque measuring unit that measures torque generated in the motor connected to the crane, and the torque acquired by the torque measuring unit increases from the controller to the motor. And a controller that reduces the rotational speed commanded by a large percentage. It has a structure for reducing the rotational speed to be commanded to the motor at a rate proportional to the value of the torque, in the measurement and the control unit in the torque measuring unit each of the inverter independently of each other It has the structure which performs control.

A crane control method according to the present invention includes a traveling device that is opposed to each other in a transverse direction that intersects the traveling direction, and a crane structure that is supported by the traveling device. A traveling wheel, a motor for transmitting power to the traveling wheel, an inverter connected to the motor for controlling the rotational speed of the motor, and a controller for giving a rotational speed command to the motor via the inverter; In the method of controlling a crane having the above, the rotational speed commanded to the motor at a rate proportional to the value of the torque by measuring the torque generated in the motor connected to each inverter independently of each other. To reduce the shift in the traveling direction of the traveling devices arranged opposite to each other.

  According to the present invention, as the torque of the motor measured by the torque measuring unit is larger, the rotational speed commanded to the motor is decreased at a larger rate, so that the torque generated in the motor is controlled toward a uniform state. The By making the torque generated in the motor uniform, it is possible to reduce the deviation in the traveling direction of the opposite traveling device, so that the crane structure is less likely to be distorted, and this distortion suppresses the vibration generated in the crane structure. It is advantageous to.

  A speed command for maintaining the rotational speed at 0 from the controller is given to the motor, and a brake device that brakes the traveling device after a predetermined standby time has elapsed can be provided. According to this configuration, the state in which the rotational speed of the motor is kept at 0 is maintained and the magnitude of the torque generated in each motor is made uniform by the control unit, that is, the deviation of the traveling direction of the opposed traveling devices is shifted. The brakes are applied to the travel device after it becomes smaller. Therefore, after braking, it is advantageous to suppress the vibration generated by the distortion of the crane structure.

  The crane may be a quay crane, and the crane structure may be provided with a boom extending in the transverse direction. This is advantageous in suppressing the boom tip from swinging in the traveling direction when the crane is traveling or stopped.

It is explanatory drawing which illustrates the crane of this invention. It is explanatory drawing which illustrates the crane of FIG. 1 in AA cross section. It is explanatory drawing which expands and illustrates the traveling device vicinity of the crane of FIG. It is explanatory drawing which illustrates the crane of FIG. 3 by BB arrow. It is explanatory drawing which illustrates typically the inverter mounted in a crane. It is a graph which illustrates the torque fluctuation of the motor of the crane of a comparative example. It is a graph which illustrates the torque fluctuation of the motor of the crane of an example. It is a graph which illustrates the fluctuation | variation of the rotational speed of the motor at the time of applying a brake. It is explanatory drawing which illustrates another embodiment of a crane.

  Hereinafter, the crane and the crane control method of the present invention will be described based on the embodiments shown in the drawings. In the drawing, the traveling direction of the crane and the traveling device is indicated by an arrow y, the traversing direction which is a horizontal direction orthogonal to the traveling direction y is indicated by an arrow x, and the vertical direction is indicated by an arrow z.

  As illustrated in FIGS. 1 to 4, the crane 1 of the present invention is composed of, for example, a quay crane. The quay crane 1 includes a traveling device 2 that is opposed to the transverse direction x, which is a horizontal direction orthogonal to the traveling direction y of the crane 1, a crane structure 3 that is supported by the traveling device 2, and a crane. And a boom 4 that is supported by the structure 3 and extends in the transverse direction x.

  The crane structure 3 includes four leg members 3a extending in the vertical direction z and a plurality of horizontal members 3b extending in the transverse direction x or the traveling direction y and connecting adjacent leg members 3a. ing. The crane 1 includes a trolley 5 that traverses along the boom 4, and a driver operates the crane 1 from a cab 6 that is provided alongside the trolley 5.

  A traveling device 2 is installed at the lower end of the crane structure 3, and the traveling device 2 is arranged in the traveling direction y, two sea-side traveling devices 2 a disposed on the sea side, and two land devices disposed on the land side. It is comprised with the side traveling apparatus 2b. In this embodiment, the two sea side traveling devices 2a and the two land side traveling devices 2b are installed in the crane structure 3, but the present invention is not limited to this configuration. The crane 1 of this invention should just be provided with the at least 2 traveling apparatus 2 arrange | positioned at intervals in the transverse direction x.

  Each traveling device 2 includes four traveling wheels 7 and one motor 8 that transmits power to the traveling wheels 7. Also, at least one traveling device 2 is provided with a brake device 9 that applies a brake to the traveling device 2.

  The traveling wheel 7 is composed of, for example, an iron wheel that moves while rolling on a rail laid on the quay 10. At this time, the brake device 9 is composed of, for example, a rail clamp that fixes the traveling device 2 with the rail interposed therebetween. Moreover, the traveling wheel 7 is comprised, for example with the rubber-made tire etc. which move on a track without rolling while rolling on the quay 10. At this time, the brake device 9 is constituted by a disc brake or the like for stopping the rotation of the tire.

  The number of traveling wheels 7 and motors 8 is not limited to the above. The number of the traveling wheels 7 can be appropriately changed according to the load to be supported by the traveling wheels 7, and the number of the motors 8 can be appropriately changed according to the magnitude of the power to be transmitted to the traveling wheels 7. For example, eight traveling wheels 7 can be installed in one traveling device 2 and power can be transmitted from the four motors 8 to the traveling wheels 7.

  Each traveling device 2 includes an inverter 11. The inverter 11 controls the rotation speed (rotation speed) of the motor 8 based on a rotation speed command from a controller installed in the cab 6.

  As illustrated in FIG. 5, the inverter 11 includes a sea-side inverter 11a that controls the motor 8 installed in the sea-side traveling device 2a, and a land-side inverter 11b that controls the motor 8 installed in the land-side traveling device 2b. It consists of The inverter 11 is installed in each traveling device 2. A controller 12 that gives a rotational speed command to the motor 8 via the inverter 11 is installed, for example, in the cab 6.

  The inverter 11 may be installed in the cab 6 together with the controller 12 without being limited to this configuration. When the crane 1 is remotely operated, the controller 12 is installed in a remote operation room.

  A configuration in which all the motors 8 installed in the sea-side traveling device 2a are controlled by one sea-side inverter 11a, and all the motors 8 installed in the land-side traveling device 2b are controlled by one land-side inverter 11b. Alternatively, the inverter 11 may be installed for each motor 8.

The inverter 11 includes a torque measuring unit 13 that measures the torque generated in the connected motor 8, and a control unit 14 that adjusts the frequency of electricity sent to the motor 8 according to the value acquired by the torque measuring unit 13. It has. In FIG. 5, the electric wires for supplying electricity to the motor 8 are indicated by solid arrows, and the signal lines for transmitting signals are indicated by broken arrows.

  When the driver operates the controller 12, a speed command is sent from the controller 12 to the control unit 14 of the inverter 11. This speed command defines the rotational speed of the motor 8, and the control unit 14 adjusts the frequency of electricity supplied from the crane 1 and supplies it to the motor 8 in accordance with this speed command. That is, the motor 8 rotates according to the rotation speed commanded from the controller 12.

  In this embodiment, one controller 12 is connected to the two inverters 11a and 11b. A switch that selects the inverter 11 that sends a rotational speed command to the controller 12 may be installed so that only the sea-side traveling device 2a or the land-side traveling device 2b travels and can be aligned. Further, the controller 12 may be connected to each of the two inverters 11.

  The torque measuring unit 13 of the inverter 11 sequentially measures the torque generated in each motor 8 and sends this value to the control unit 14. The controller 14 sequentially performs control to decrease the rotation speed commanded from the controller 12 to the motor 8 at a larger rate as the measured torque value is larger. The measured torque value and the rate at which the rotational speed is reduced are preset in the control unit 14.

  The amount (correction amount) by which the actual rotational speed is reduced with respect to the speed command sent from the controller 12 to the motor 8 can be determined based on, for example, the mathematical formula D = aT / 100. Here, D is the correction amount (%), a is a preset constant, and T is the ratio (%) of the measured torque to the rated torque of the motor 8. That is, the correction amount D for decreasing the rotational speed commanded from the controller 12 to the motor 8 increases in proportion to the measured torque value.

  A case where the constant a is set to 3 will be described as an example. When the torque of the motor 8 measured by the torque measuring unit 13 is equal to the rated torque of the motor 8 (T = 100%), the correction amount D is 3% according to the above formula, so that the control unit 14 is determined by the driver. The motor 8 is rotated at a speed obtained by subtracting 3% from the rotational speed input to the controller 12. That is, when the rotational speed command is 100% (rated speed), the actual motor 8 rotates at 97% of the rated speed, and when the speed command is 50%, it rotates at the rotational speed of 47% of the rated speed.

  When the torque of the motor 8 measured by the torque measuring unit 13 is 50% of the rated torque (T = 50%), the control unit 14 subtracts 1.5% from the rotational speed input to the controller 12 by the driver. The motor 8 is rotated at the rotation speed. In other words, when the rotational speed command is 100% (rated speed), the actual motor 8 rotates at a rotational speed of 98.5% of the rated speed, and when the speed command is 50%, the actual speed is 48.5% of the rated speed. It rotates at the rotation speed.

  When the measured torque of the motor 8 is 200% with respect to the rated torque (T = 200%), the control unit 14 causes the motor to rotate at a rotational speed obtained by subtracting 6.0% from the rotational speed input to the controller 12 by the driver. Rotate 8 In other words, the actual motor 8 rotates at a rotational speed of 94% of the rated speed when the rotational speed command is 100% (rated speed), and rotates at a rotational speed of 44% of the rated speed when the speed command is 50%. To do.

The value of the constant a is not limited to the above, and can be changed as appropriate according to the scale of the crane and the configuration of the equipment. The value of the constant a is set, for example, within a range of 1 to 20, preferably within a range of 2 to 6. A knob for changing the constant a may be installed in the controller 12 so that the driver can change the constant a at any time.

  In addition to the rated torque of the motor 8, the torque ratio T measured by the torque measuring unit 13 may be obtained using a predetermined torque value as a reference value. Further, for example, the rotation speed of the motor 8 may be controlled at a predetermined correction rate with respect to the speed command. Specifically, for example, when the correction ratio is 10% with respect to a speed command of 100% of the rated speed, the motor 8 is controlled at a rotational speed of 90% with respect to the speed command. In this case, when the speed command is 100% of the rated speed, the rotational speed of the motor 8 is 90% of the rated speed, and when the speed command is 50% of the rated speed, the rotational speed of the motor 8 is 45% of the rated speed. Become.

  The correction amount D for reducing the rotation speed of the motor 8 with respect to the torque value measured by the torque measuring unit 13 is not limited to the above, and the state in which the rotation speed is decreased at a larger rate as the measured torque value is larger. It is only necessary that the control unit 14 is set. For example, instead of the mathematical formula for obtaining the correction amount D described above, a table in which the correction amount D is determined in advance according to the ratio of the generated torque to the rated torque of the motor 8 as illustrated in Table 1 may be set. Formulas and tables for determining the rotation speed of the motor 8 can be stored in the control unit 14, for example.

  The sea-side inverter 11a and the land-side inverter 11b perform torque measurement by the torque measurement unit 13 and control of the rotational speed of the motor 8 by the control unit 14 independently of each other. That is, in the present invention, when torque measurement and control of the rotational speed of the motor 8 are performed, no signal is transmitted between the inverters 11 in this regard.

  Next, experiments conducted to confirm the effects of the present invention will be described. In the comparative example, an experiment was performed in which a real machine of a quay crane not provided with the control unit 14 was run and the torque generated in each motor was measured. The graph illustrated in FIG. 6 shows the result of this experiment. The vertical axis indicates the measured torque (%) when the rated torque of the motor is 100% and the rated speed of the motor is 100%. The rotational speed (%) is shown, and the horizontal axis shows the elapsed time (sec). The alternate long and short dash line indicates the rotational speed of the motor, the solid line indicates the measured torque of the motor installed in the sea-side traveling device, and the broken line indicates the measured torque of the motor installed in the land-side traveling device.

  As illustrated in FIG. 6, it can be seen that the torque generated by the motor of the land-side traveling device indicated by the broken line is relatively larger than that of the motor of the sea-side traveling device indicated by the solid line. This is because when a quay crane is driven, if the controller gives the same rotational speed command as the land-side traveling device from the controller to the sea-side traveling device, the sea-side traveling becomes relatively heavy as illustrated by the broken line in FIG. This is because a delay occurs in the device 2a. That is, the sea-side traveling device and the land-side traveling device are shifted in the traveling direction y, and the preceding land-side traveling device travels so as to drag the sea-side traveling device, so that the torque generated in the motor of the land-side traveling device Is relatively larger. In addition, the white arrow of FIG. 4 has shown the traveling direction of the quay crane.

  Further, as illustrated in FIG. 6, it can be seen that the phases of torque fluctuations generated in the motor of the sea side traveling device and the motor of the land side traveling device are frequently reversed. This indicates that the sea-side traveling device and the land-side traveling device are repeatedly approaching and separating in the traveling direction y, and that the compressive force and tensile force in the traveling direction y are alternately generated in the crane structure. ing. Due to the shift in the traveling direction y between the sea-side traveling device and the land-side traveling device, the crane structure is deformed and vibration is generated. When the crane structure vibrates, particularly the tip of the boom is greatly shaken in the traveling direction.

  About the quay crane 1 of the Example of this invention, the experiment similar to a comparative example was done. The graph illustrated in FIG. 7 shows the results of this experiment. As illustrated in FIG. 7, it can be seen that there is almost no difference in magnitude between the torque generated in the motor 8 of the sea-side traveling device 2a and the torque generated in the motor 8 of the land-side traveling device 2b. If a traveling device 2 is in a relatively preceding position, a large torque is generated in the motor 2 of the traveling device 2. However, since the rotational speed of the motor 8 is decelerated according to the correction amount D, the position of the traveling device 2 is controlled in a direction to cancel the preceding state. Therefore, when the quay crane 1 is caused to travel, there is almost no deviation in the traveling direction y between the sea-side traveling device 2a and the land-side traveling device 2b, and the crane 1 travels while maintaining a relative position.

  Further, as illustrated in FIG. 7, it can be seen that the phases of torque fluctuations generated in the motor 8 of the sea-side traveling device 2a and the motor 8 of the land-side traveling device 2b are almost synchronized. This indicates that the sea-side traveling device 2a and the land-side traveling device 2b are simultaneously generating a force on the crane structure 3 in the same direction in the traveling direction y. Since there is almost no deviation in the traveling direction y of the traveling device 2 and the phase of torque fluctuation is synchronized, the crane structure 3 is hardly distorted. Therefore, the vibration which generate | occur | produces in the quay crane 1 at the time of driving | running | working can be suppressed.

  When the swing width of the boom tip when the quay crane was run was measured, the index of the quay crane 1 of the example was taken as index 100 when the swing width in the running direction y of the boom tip of the comparative quay crane was taken as a reference. Became 15-45. The smaller the index value, the smaller the swing width.

  When stopping the quay crane 1, the driver sends a speed command for setting the rotational speed of the motor 8 to 0% of the rated rotational speed, that is, 0 rpm, from the controller 12 to the control unit 14. As illustrated in FIG. 8, the control unit 14 starts the control to maintain this 0 rpm at the time t <b> 0 when the rotational speed of the motor 8 is gently reduced to 0 rpm (control start point). For example, when the quay crane 1 is pushed in the traveling direction y by wind or the like, a force that opposes this external force is generated in the motor 8 and the rotational speed of the motor 8 is maintained at 0 rpm. Brake is applied by the brake device 9 installed in the traveling device 2 after a predetermined waiting time T1 of about 2 to 10 sec, for example, from the time when the rotational speed of the motor 8 becomes 0 rpm (brake operating point).

Even during the standby time, the inverter 11 measures the torque of the motor 8 by the torque measuring unit 13 and sequentially performs control to decrease the rotational speed commanded to the motor 8 at a larger rate as the torque value increases. Therefore, even after the control for setting the rotational speed of the motor 8 to 0 rpm is started, the sea-side traveling device 2a and the land-side traveling device 2b are displaced in the traveling direction y, and the crane structure 3 is distorted. In this case, a force in a direction to release the distortion is generated in the traveling device 2. As illustrated in FIG. 4, when the quay crane 1 travels in the direction of the white arrow, the sea-side traveling device 2a is in a delayed position and the land-side traveling device 2b is in a preceding position, as illustrated by a broken line. In some cases, the motor 8 of the land-side traveling device 2b generates a force in a direction approaching the sea-side traveling device 2a in the traveling direction y.

  When torque due to this force is generated in the motor 8 of the land-side traveling device 2b, the control unit 14 performs control to reduce the rotational speed of the motor 8 in accordance with the magnitude of the torque. Since a speed command is issued from the controller 12 to the motor 8 so as to stop at a rotational speed of 0% with respect to the rated rotational speed, for example, when the torque generated in the motor 8 is 100% of a predetermined reference value, The control unit 14 performs control to rotate the motor 8 at a rotational speed obtained by reducing the rotational speed by 3%, that is, −3% of the rated rotational speed. That is, the motor 8 of the land-side traveling device 2b reverses and moves in a direction approaching the sea-side traveling device 2a.

  Since each traveling device 2 moves so that the torque generated in each motor 8 is reduced, the deviation of the traveling direction y of the traveling device 2 is reduced. That is, the residual strain of the crane structure 3 is released, and then the traveling device 2 is fixed by the brake device 9. Therefore, it is possible to suppress the occurrence of vibration in the crane structure 3 after braking and swinging of the boom tip in the traveling direction y.

  The timing to apply the brake is not limited to after the standby time T1 has elapsed. For example, the rotational speed of each motor 8 or the traveling speed of the traveling device 2 is monitored with a speedometer or the like, and when the rotational speeds of all the motors 8 become 0 or the traveling speed of the traveling devices 2 becomes 0 m / min. Sometimes, the brake device 9 may be activated. According to this configuration, the traveling device 2 can be fixed by the brake when the traveling device 2 is stopped in the traveling direction y and each traveling device 2 is stopped. Therefore, since the brake is applied after the distortion of the crane structure 3 is completely released, it is advantageous for suppressing the vibration after the crane 1 is stopped.

  After stopping the quay crane in motion and applying the brake, an experiment was conducted to measure the swing width of the boom tip. The index of the quay crane 1 of the example was 13 to 38 when the index 100 was set based on the swing width in the traveling direction y of the boom tip of the quay crane of the comparative example not provided with the control unit 14. The smaller the index value, the smaller the swing width.

  According to the present invention, since the crane structure can be prevented from being distorted and vibrated when the crane 1 is traveling and stopped, the boom tip hardly swings during the waiting time T1. Therefore, even during the waiting time T1, the driver can align the container to be handled with the boom 4 and can proceed with preparations for starting the cargo handling operation even before the brake is applied. Since no waiting time is required until the boom swings down, it is advantageous for improving cargo handling efficiency.

  Even in a quay crane that employs a mono box-structured boom for weight reduction, the application of the present invention can greatly suppress the swing of the boom tip. Moreover, it is a quay crane provided with a boom with a long full length with an increase in size, and by applying the present invention, swinging of the boom tip can be suppressed.

  As illustrated in FIG. 9, the crane 1 of the present invention can be constituted by a portal crane, for example. Not only this but the crane 1 of this invention is applicable also to another crane, if it is a crane provided with the traveling apparatus arrange | positioned at intervals in the transverse direction x.

In the portal crane 1, the diesel generator 15 is disposed above one traveling device 2 or travels with a container suspended, so that the wheel load of one traveling device 2 is larger than the other. There is. Therefore, by adopting the inverter 11 including the torque measuring unit 13 and the control unit 14, it is possible to suppress the traveling device 2 from shifting in the traveling direction y and to suppress the vibration of the crane 1.

  In the case of the portal crane 1 in which the traveling wheels 7 are made of rubber tires, when the traveling device 2 is displaced in the traveling direction y, the crane structure 3 is distorted and rotated about the vertical direction z as the central axis. A moment is generated. When the portal crane 1 is caused to travel in such a state, the crane 1 travels while bending in the rotational direction of the rotational moment.

  Since the shift of the traveling direction y of the traveling device 2 can be reduced by the present invention, it is advantageous for improving the straight traveling performance during traveling. Since the straight traveling performance of the portal crane 1 during traveling can be improved, it is advantageous when the traveling is automated.

DESCRIPTION OF SYMBOLS 1 Crane 2 Traveling device 2a Sea side traveling device 2b Land side traveling device 3 Crane structure 3a Leg member 3b Horizontal member 4 Boom 5 Trolley 6 Driver's cab 7 Motor wheel 8 Motor 9 Brake device 10 Quay wall 11 Inverter 11a Sea side inverter 11b Land Side inverter 12 Controller 13 Torque measurement unit 14 Control unit 15 Diesel generator

Claims (9)

A traveling device which is opposed to the traveling direction across the traveling direction with an interval, and a crane structure supported by the traveling device,
Each of the traveling devices includes a traveling wheel, a motor that transmits power to the traveling wheel, an inverter that is connected to the motor and controls the rotational speed of the motor, and a rotational speed command to the motor via the inverter. A crane having a controller for providing
Each inverter has a torque measuring unit that measures the torque generated in the motor connected thereto, and the greater the value of torque acquired by the torque measuring unit, the larger the rotational speed commanded from the controller to the motor. And a control unit that decreases at a rate,
The control unit has a configuration to reduce the rotational speed commanded to the motor at a rate proportional to the torque value measured by the torque measurement unit,
Each of the inverters has a configuration in which measurement by the torque measurement unit and control by the control unit are performed independently of each other. A traveling device which is opposed to the traveling direction across the traveling direction with an interval, and a crane structure supported by the traveling device,
Each of the traveling devices includes a traveling wheel, a motor that transmits power to the traveling wheel, an inverter that is connected to the motor and controls the rotational speed of the motor, and a rotational speed command to the motor via the inverter. A crane having a controller for providing
Each inverter has a torque measuring unit that measures the torque generated in the motor connected thereto, and the greater the value of torque acquired by the torque measuring unit, the larger the rotational speed commanded from the controller to the motor. And a control unit that decreases at a rate,
The control unit has a configuration to reduce the rotational speed commanded to the motor at a predetermined correction rate,
Each of the inverters has a configuration in which measurement by the torque measurement unit and control by the control unit are performed independently of each other. The crane according to claim 1 or 2, wherein control by the control unit is performed when the torque acquired by the torque measuring unit is in a range equal to or less than a rated torque of the motor. A brake that applies a speed command to the motor to keep the rotational speed at 0 from the controller, and brakes the traveling device when the rotational speed of all the motors is 0 or the traveling speed of the traveling device becomes 0 The crane according to any one of claims 1 to 3, comprising a device. The crane according to any one of claims 1 to 4 , wherein the crane is a quay crane, and the crane structure is provided with a boom having a mono box structure extending in a transverse direction. A traveling device which is opposed to the traveling direction across the traveling direction with an interval, and a crane structure supported by the traveling device,
Each of the traveling devices includes a traveling wheel, a motor that transmits power to the traveling wheel, an inverter that is connected to the motor and controls the rotational speed of the motor, and a rotational speed command to the motor via the inverter. A control method of a crane having a controller for providing
Each of the inverters is arranged independently of each other by measuring the torque generated in the connected motor and reducing the rotational speed commanded to the motor at a rate proportional to the value of the torque. A crane control method characterized by reducing a shift in a traveling direction of the traveling device. The crane control method according to claim 6, wherein when the torque generated in the motor is in a range equal to or less than a rated torque of the motor, the rotational speed commanded to the motor is reduced. Claim braking to said running device when the rotation speed to the motor from the controller gives a speed command to maintain 0, the running speed of all the rotational speed of the motor is zero or the running device has become 0 The crane control method according to 6 or 7 . The crane control method according to any one of claims 6 to 8, wherein the crane is a quay crane, and the crane structure is provided with a boom having a mono box structure extending in a transverse direction.

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