Crane and crane control method

Abstract

A crane capable of reducing swing of a load even in the case where a length of a wire rope is long at the time of micro-motion operation in the case where a moving time is short. A speed command value (Vout) for suppressing swing of a load by a swing suppression control of a load is calculated from a load target speed command value (Vtgt) and at least a length of a wire rope, and in the case where an input time of the load target speed command value (Vtgt) reaches a control start waiting time (Twait) or the load target speed command value (Vtgt) starts deceleration, a horizontal moving device is driven in accordance with the speed command value (Vout) of the swing suppression control of the load, and in other cases, the horizontal moving device is driven in accordance with the load target speed command value (Vtgt).

Description

Technical Field

[0001] This invention relates to a crane for suspending and transporting a load and a crane control method, and more particularly to a crane and a crane control method having the function of suppressing the swaying of the load. Background Technology

[0002] In recent years, with the aging of skilled crane operators and the shortage of manpower caused by the increase in the number of cranes, inexperienced operators have more opportunities to drive (operate) cranes. Moreover, inexperienced operators especially face the following technical problems: they are not proficient in anti-swaying operations to suppress the swing of the load, resulting in a high risk of collisions and clamping accidents caused by the swing of the load. In addition, it takes time for the swing of the load to subside, which increases the operation time.

[0003] Therefore, for greater safety and improved operational efficiency, cranes with a crane sway suppression function that automatically suppresses load sway are desirable. As a technology responding to this desire, for example, a crane disclosed in Japanese Patent Application Publication No. 2018-2391 (Patent Document 1) is known. The crane described in Patent Document 1 is configured to calculate the model speed value of the load based on the control speed value of the trolley (handcart) or bridge (hereinafter referred to as the horizontal moving device) and the model of the horizontal moving device, in a manner that makes the model speed value of the load consistent with or close to the target speed command value of the load (input from the input device).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-2391 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] However, in Patent Document 1, the target speed command value input from the input device is configured such that if the input time of the target speed command value has not reached the predetermined input time, that is, if the crane's movement time is short or if a micro-motion operation (short-term switching in one direction) is performed, the results of the model calculation and control calculation are not output, but the input target speed command value is output.

[0009] Therefore, Patent Document 1 cannot sufficiently suppress residual load sway when the crane's travel time is short or during micro-movement operations. Furthermore, when the wire rope is long, residual load sway is sometimes not completely suppressed either.

[0010] The present invention is made entirely in view of the problems therein, and its object is to provide a new crane and a crane control method that can reduce residual load sway even when the crane travel time is short, when micro-movement is performed, and / or when the wire rope is long.

[0011] Technical solutions for solving technical problems

[0012] The first feature of this invention is a crane comprising: a hoisting device for moving a suspended load vertically by raising and lowering a wire rope; a horizontal moving device for moving the suspended load horizontally by mounting the hoisting device; an operation input device for generating a target speed command value for the suspended load; a speed command value calculation device for generating a speed command value for the horizontal moving device based on the target speed command value for the suspended load; and an electric motor control device for driving and controlling the horizontal moving device based on the speed command value.

[0013] The speed command value calculation device has:

[0014] A load sway suppression control device, which calculates the load sway suppression speed command value for the horizontal moving device to suppress the sway of the load based on the target speed command value of the load and the length of the wire rope; and

[0015] The switching device outputs a load swing suppression speed command value from the load swing suppression control device when the input time of the load target speed command value from the operation input device reaches a predetermined control start waiting time, or when the load target speed command value from the operation input device begins to decelerate; otherwise, it outputs the load target speed command value from the operation input device.

[0016] A second feature of the present invention is a crane comprising: a hoisting device for moving a suspended load vertically by raising and lowering a wire rope; a horizontal moving device for moving the suspended load horizontally by mounting the hoisting device; an operation input device for generating a target speed command value for the suspended load; a speed command value calculation device for generating a speed command value for the horizontal moving device based on the target speed command value for the suspended load; and an electric motor control device for driving and controlling the horizontal moving device based on the speed command value.

[0017] Speed ​​command value calculation device,

[0018] If the elapsed time between the target speed command value from the operation input device and the target speed value falling below the specified speed value is shorter than the specified brake operating waiting time, and the speed command value from the speed command value calculation device becomes negative, then the horizontal moving device will be controlled to move freely by inertia.

[0019] If the elapsed time is longer than the brake operating waiting time, and the speed command value from the speed command value calculation device becomes lower than the brake operating speed value, brake control to maintain the position of the horizontal moving device is executed.

[0020] The effects of the invention

[0021] According to the present invention, residual load sway can be reduced even when the crane has a short travel time, has undergone micro-movement, and / or has a long wire rope. Attached Figure Description

[0022] Figure 1 This is a structural diagram showing the structure of the crane, which is the subject of this invention.

[0023] Figure 2 This is a block diagram illustrating the structure of the control block of a crane to which the present invention is applied.

[0024] Figure 3 This is an explanatory diagram illustrating the target speed command value of the suspended load generated by the operation input device.

[0025] Figure 4 This is a block diagram illustrating the structure of the speed command value calculation device in the first embodiment of the present invention.

[0026] Figure 5 This is an explanatory diagram showing the target speed command value of the suspended load, the output of the control to suppress the sway of the suspended load, and the output after the limit processing during micro-motion operation.

[0027] Figure 6 This is an illustration of the time response of the horizontal movement speed and the amount of sway of the suspended load when using existing technology for load sway suppression control, which assigns a trapezoidal wave velocity waveform as the target speed command value of the suspended load.

[0028] Figure 7 This is an explanatory diagram illustrating the time response of the horizontal movement speed and the amount of sway of the suspended load when using existing technology for load sway suppression control, which assigns the target speed command value of the suspended load to the triangular wave speed waveform during micro-motion operation.

[0029] Figure 8 This is a control flowchart illustrating the operation of the switching device in the first embodiment of the present invention.

[0030] Figure 9 This is an explanatory diagram illustrating the target speed command value for the suspended load and the output of the switching device in the first embodiment of the present invention.

[0031] Figure 10This is an explanatory diagram showing the time variation of the speed command value and the amount of sway of the suspended weight during micro-motion operation in the first embodiment of the present invention.

[0032] Figure 11 This is an explanatory diagram showing the time variation of horizontal movement speed and load swing amount during micro-motion operation in the case of increased brake working waiting time in the second embodiment of the present invention.

[0033] Figure 12 This is a control flowchart illustrating the operation of the brake in the second embodiment of the present invention.

[0034] Figure 13 This is an explanatory diagram showing the time variation of the speed command value and the amount of sway of the suspended weight during micro-motion operation in the second embodiment of the present invention.

[0035] Figure 14 This is an explanatory diagram showing the target speed command value for the suspended load, the output of the control for suppressing the sway of the suspended load, and the output after limiting processing when the length of the wire rope is long in the second embodiment of the present invention.

[0036] Figure 15 This is an explanatory diagram showing the time variation of the speed command value and the amount of sway of the suspended weight when the length of the wire rope is long in the second embodiment of the present invention.

[0037] Figure 16 This is a block diagram illustrating the structure of the speed command value calculation device in the third embodiment of the present invention. Detailed Implementation

[0038] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments, and various modifications and applications are also included within the scope of the technical concept of the present invention.

[0039] Here, the present invention is effective for cranes that can move loads horizontally, and can be applied not only to cranes that use trolleys (also called hoisting trolleys) and bridges to move loads both horizontally and longitudinally (e.g., bridge cranes), but also to cranes that only move loads horizontally or longitudinally (e.g., unloaders). That is, the term "crane" as used below includes all kinds of cranes capable of moving loads horizontally.

[0040] Furthermore, goods (lifted loads) transported by cranes are suspended and transported using wire ropes, chains, etc. However, in this invention, there are no limitations on any suspension tool that can be used to suspend goods, nor are there any restrictions on its material or shape. Therefore, as mentioned above, the term "wire rope" is used as a general term for suspension tools used to suspend goods. That is, "wire rope" includes not only so-called wire ropes, but also chains, belts, cables, wires, cords, ropes, etc.

[0041] Example 1

[0042] Next, the structure and operation of the crane according to the first embodiment of the present invention will be described.

[0043] Furthermore, in each of the accompanying drawings, the same reference numerals are used to label the same equipment (devices, components), and in the following description, the description of the equipment that has already been described is sometimes omitted.

[0044] Figure 1 This represents a schematic structure of a ceiling crane. Furthermore, as described above, the present invention is not limited to ceiling cranes.

[0045] exist Figure 1 In this crane 1, there are: a runway 2 set along the walls on both sides of a building (not shown), a girder 3 that moves along the upper surface of the runway 2, and a trolley 4 that moves along the lower surface of the girder 3. The girder 3 and the trolley 4 are provided with wheels driven by electric motors, through which the girder 3 and the trolley 4 can move.

[0046] Additionally, a hoist (not shown) is installed at the lower part of the trolley 4. This hoist is used to raise or lower the wire rope 5, thereby raising or lowering the hook 6 at the front end of the wire rope 5. The load 8 is suspended directly from the hook 6 or suspended via the cable 7. As the hook 6 rises or falls, the load 8 rises or falls.

[0047] That is, the crane 1 can move the load 8 horizontally by moving the bridge 3 horizontally (hereinafter referred to as "longitudinal movement") and the trolley 4 horizontally (hereinafter referred to as "lateral movement"), and raise and lower the load 8 vertically (up and down) by means of a hoisting device. In this embodiment, horizontal movement is achieved by the lateral movement of the trolley 4 and the longitudinal movement of the bridge 3.

[0048] exist Figure 1In this embodiment, the trolley 4 and the bridge 3 are equivalent to "horizontal moving devices," but either the trolley 4 or the bridge 3 can also be used as a "horizontal moving device." This embodiment relates to the action of moving the suspended load in the horizontal direction; therefore, the following description of this embodiment focuses on the action of horizontal movement based on "lateral" and "longitudinal" movements. Furthermore, in the following description, the movement of the suspended load refers to one or both of driving the movement of the trolley 4 (lateral) and driving the movement of the bridge 3 (longitudinal).

[0049] Figure 2 This is a control block diagram of the crane according to this embodiment. Furthermore, in Figure 2 In the illustration, for simplicity, the crane 1, which uses the trolley 4 for horizontal movement, and the bridge 3 for longitudinal movement are shown. Figure 2 The details are omitted. Additionally, the drive components, such as the electric motors used for moving the trolley 4 and the bridge 3, are omitted.

[0050] Figure 2 The control box of the crane includes a speed command value calculation device 100 for calculating the speed command values ​​of the horizontal moving devices (bridge 3 and trolley 4) and an electric motor control device 300. The speed command values ​​from the speed command value calculation device 100 are provided to the electric motor control device 300, and through the electric motor control device 300, the power corresponding to the speed command values ​​is supplied to the electric motors of the bridge 3 and trolley 4.

[0051] The speed command value calculation device 100 typically uses a general-purpose computer and includes: a microprocessor unit (MPU) 101 that performs calculations such as generating speed command values ​​using built-in programs and data; a memory 102 that stores the aforementioned programs and data; and an input / output control unit 103 for inputting data and signals from external sources and outputting signals processed by the MPU 101 to the outside. The MPU 101, memory 102, and input / output control unit 103 are connected via a bus line 104 for transmitting and receiving signals and data.

[0052] The input / output control unit 103 is connected to an operation input device 200 that generates a target speed command value for the suspended load. The operation input device 200 has an operation terminal device 201 for operation by the operator. The operation terminal device 201 is provided with operation buttons 202 corresponding to the forward, backward, right, left, upward, and downward directions, which are the movement directions of the suspended load. The target speed command value for the suspended load is generated corresponding to the pressed operation button and output to the speed command value calculation device 100.

[0053] Next, based on Figure 3 This section describes an example of how the operation input device 200 generates a speed command value for the suspended target.

[0054] Figure 3 (a) indicates the case where the operation button 202 is pressed for a long time. When the operation button 202 is pressed at time (t1) (becomes ON (pressed)), the target speed command value of the load increases in the direction of the pressed operation button. During the period when the operation button 202 is continuously pressed, the constant speed moving speed value is maintained. When the operation button 202 is released at a later time (t2) (becomes OFF (released)), the target speed command value of the load decreases and eventually becomes "0".

[0055] on the other hand, Figure 3 In (b), when the button is pressed for a short time, i.e. the crane moves for a short time, and in the case of micro-motion operation, when the operation button 202 is pressed at time (t1′) (becomes ON), the target speed command value of the load corresponding to the direction of the pressed operation button increases. When the operation button 202 is released at time (t2′) before reaching the constant speed value (becomes OFF), the target speed command value of the load decreases and eventually becomes "0".

[0056] In the speed command value calculation device 100, in addition to inputting the target speed command value of the hoisting load generated by the operation input device 200, the target speed command value of the hoisting load generated based on the movement plan of the hoisting load can also be input from the upper control system such as the production management system.

[0057] The electric motor control device 300 takes the speed command value output from the speed command value calculation device 100 as input and controls the horizontal movement (lateral movement) speed of the vehicle 4. The specific structure of the electric motor control device 300 is not shown, but it can be constructed from a general-purpose computer and inverter circuit, similar to the speed command value calculation device 100. Alternatively, the electric motor control device 300 can be mounted in the same housing as the speed command value calculation device 100.

[0058] Furthermore, the speed command value calculation device 100 not only outputs the speed command value for controlling the trolley 4, but also outputs the speed command value for controlling the horizontal (longitudinal) movement speed of the bridge 3 in the case of longitudinal control. Figure 2 (Omitted). On one side of the cable tray 3, this speed command value can be used to control the horizontal (longitudinal) movement speed of the suspended load.

[0059] In addition, the speed command value calculation device 100 inputs information from various detectors, such as the wire rope length output by a wire rope length detector (not shown) and the amount of sway of the suspended weight output by a suspended weight sway detector (also not shown).

[0060] Figure 4This is a function block representing the speed command value calculation device 100. The function block represents the functions performed by the MPU 101 as control blocks. The speed command value calculation device 100 takes the target lifting speed command value (Vtgt) from the operation input device 200 as input, calculates the speed command value (Vout) of the horizontal moving device (bridge 3 and trolley 4), and outputs it to the electric motor control device 300.

[0061] The speed command value calculation device 100 consists of a load swing suppression control device 110 and a switching device 120. The load swing suppression control device 110 performs a prescribed calculation based on the target speed command value (Vtgt) of the load and the length of the wire rope to output a load swing suppression speed command value (Vsps) for the horizontal moving device used to suppress the swing of the load. The switching device 120 switches between the target speed command value (Vtgt) of the load and the load swing suppression speed command value (Vsps).

[0062] The computing unit of the load sway suppression control device 110 can be configured, for example, as follows: It consists of a model computing unit 111, a feedback control computing unit 112, a feedforward control computing unit 113, an adder 114, and a limit processing unit 115. The model computing unit 111 calculates the load model speed value (Vmdl) based on the speed command value (Vout) of the horizontal moving device output from the switching device 120 and input to the electric motor control device 300, and a predetermined crane model. The feedback control computing unit 112 performs feedback control calculations based on the load model speed (Vmdl). The feedforward control computing unit 113 performs feedforward control calculations based on the load target speed command value (Vtgt). The adder 114 adds the outputs of the feedback control computing unit 112 and the feedforward control computing unit 113. The limit processing unit 115 performs limit processing (also called limit treatment) on the output of the adder 114.

[0063] In the model calculation device 111, the crane is modeled in advance, and the speed value of the crane model (Vmdl) is calculated according to the speed command value (Vout) of the horizontal moving device as follows.

[0064] Vmdl(s)=(2*zr*wr*s+wr 2 )

[0065] / (s 2 +2*zr*wr*s+wr 2 )*Vout(s)

[0066] Here, “Vout(s)” is the Laplace transform of the speed command value of the horizontal moving device, “Vmdl(s)” is the Laplace transform of the speed value of the suspended model, “wr” is the angular frequency of the suspended oscillation, and “zr” is the attenuation ratio of the suspended oscillation. wr and zr are given by the following formulas.

[0067] wr = (g / L) 1 / 2

[0068] zr=Lv / L / wr

[0069] Here, "L" is the length of the oscillator of the suspended weight (distance from the center of rotation to the center of gravity of the suspended weight) obtained from the length of the wire rope, "Lv" is the time change of the wire rope length (velocity), and "g" is the acceleration due to gravity.

[0070] Feedback control calculation unit 112 and feedforward control calculation unit 113 calculate the load swing suppression speed command value (Vsps) for the horizontal moving device used to suppress load swing based on the target speed command value (Vtgt) and the load model speed value (Vmdl). This can be achieved by performing calculations such as those described in "Zhang Shimono Tagawa, Control of Crane Movement and Vibration Due to Length Changes Caused by DMM, Proceedings of the Japan Society of Mechanical Engineers Transportation and Logistics Division Conference, Vol.20 (2011)".

[0071] Vfb(s)=(nb1*s+nb0) /

[0072] (s 3 +d2*s 2 +d1*s+d0)*Vmdl(s)

[0073] Vff(s)=(nf3*s 3 +nf2*s 2 +nf1*s+nf0) /

[0074] (s 3 +d2*s 2 +d1*s+d0)*Vtgt(s)

[0075] Here, “Vfb(s)” is the Laplace transform of the feedback control output, “Vff(s)” is the Laplace transform of the feedforward control output, and “nb1, nb0, nf3, nf2, nf1, nf0, d2, d1, d0” are parameters determined by the following performance relative to the target speed command value (Vtgt) of the suspended load and the suppression performance of the suspended load's sway, which vary according to the angular frequency (wr) of the suspended load's sway.

[0076] The outputs of the feedback control calculation unit 112 and the feedforward control calculation unit 113 are added together in the adder 114 to output the load swing suppression speed command value (Vsps) of the horizontal moving device that can suppress the load swing.

[0077] Furthermore, in the restriction processing device 115, the load swing suppression speed command value (Vsps) is restricted by taking into account the speed and acceleration limits of the horizontal moving device.

[0078] Figure 5 The values ​​represent the target speed command value (Vtgt) of the suspended load during micro-motion operation, the output of the adder 114 (suspension swing suppression speed command value Vsps), and the output of the limiting processing device 115 (limited processing output). In order to suppress the swing of the suspended load caused by deceleration during micro-motion operation, the horizontal moving device must be driven according to the suspension swing suppression speed command value (Vsps) obtained by adding the results of the feedback control calculation and the feedforward control calculation of the suspension swing suppression control.

[0079] However, the electric motor used in the horizontal moving device is an induction motor, which cannot reverse the rotation direction without temporarily stopping, and cannot operate according to the "negative" (opposite rotation direction) speed command value. Therefore, the limit processing device 115 performs calculations (limit processing) on ​​the saturation state based on the speed limit and acceleration limit of the horizontal moving device, and outputs the speed command value that enables the horizontal moving device to operate.

[0080] In addition, “wr, zr, nb1, nb0, nf3, nf2, nf1, nf0, d2, d1, d0” can be calculated based on the oscillator length (L) of the suspended weight. The oscillator length (L) of the suspended weight is obtained by adding the distance from the hook to the center of gravity of the suspended weight to the wire rope length (distance from the rotation center to the hook 6) output by the wire rope length detector. However, it can also be calculated based on the angular frequency (wr) of the suspended weight swing. The angular frequency (wr) of the suspended weight swing is obtained based on the amount of suspended weight swing output by the suspended weight swing detector.

[0081] In addition to the structure of the load sway suppression control device 110 described above, it can also be configured by using a cutoff bandpass filter that cuts off the frequency of the load sway to the target speed command value (Vtgt) of the load, and setting the load sway amount output as the load sway detector to "0".

[0082] Figure 6This represents the time response of the speed of the horizontal moving device (horizontal moving speed) and the amount of sway of the load (load sway) when a trapezoidal speed waveform (equivalent to the case where the operation button is pressed for a long time) is applied as the target speed command value (Vtgt). It can be understood that in the case of "no control" (using the target speed command value) without load sway suppression control, as shown by the dashed line, load sway (residual load sway) occurs after the crane stops. However, by applying "load sway suppression control" (represented by the solid line), the residual load sway can be suppressed.

[0083] and Figure 7 This represents the time response of horizontal movement speed and load sway when a micro-motion operation involving acceleration and deceleration over a short period of time is performed, using the target speed command value (Vtgt) for the load. In the "no control" scenario, the target speed command value (Vtgt) is used, resulting in a triangular waveform for the horizontal movement speed, as shown by the dashed line. However, when "load sway suppression control" is applied, as shown by the solid line, a steep (aggressive) acceleration control is applied at the start of acceleration, and residual load sway can sometimes be worse than in the "no control" scenario.

[0084] To suppress this phenomenon, Patent Document 1 does not perform "load sway suppression control" when the crane's movement time is short or when micro-motion is performed, but instead uses the load target speed command value (Vtgt). However, when using the load target speed command value (Vtgt), the residual load sway cannot be reduced compared to the "no control" situation, and further improvement is desired.

[0085] Therefore, in response to this desire, in this embodiment, as Figure 4 As shown, a switching device 120 is configured to switch between the target speed command value (Vtgt) output from the operation input device 200 and the swing suppression speed command value (Vsps) output from the swing suppression control device 110, and the switching device 120 operates as described below.

[0086] That is, when operation button 202 is pressed to start acceleration (generation of acceleration signal), the target speed command value (Vtgt) is applied to the electric motor control device 300 as the speed command value (Vout). When operation button 202 is released during a period shorter than the predetermined waiting time for the start of the load swing suppression control, and deceleration begins (generation of deceleration signal), the load swing suppression speed command value (Vsps) is applied to the electric motor control device 300 as the speed command value (Vout). Here, acceleration and deceleration commands are output using operation button 202, but the same applies when acceleration and deceleration commands are output according to instructions from the upper control system. Furthermore, the start time of the load swing suppression control can be a predetermined time or a predetermined time determined based on the actual operating state.

[0087] Figure 8 This describes the control flow used to cause the switching device 120 to perform the aforementioned actions. Figure 9 Indicate execution Figure 8 The switching states of the target speed command value (Vtgt) and the swing suppression speed command value (Vsps) during the control process. The following uses... Figure 8 , Figure 9 This describes the operation of the switching device 120. Furthermore, this control process is initiated (started) by polling in conjunction with the operation of the operation button 202 while the crane is being controlled to move. Moreover, it can be started even if there is an external interruption.

[0088] Step S10

[0089] In step S10, it is determined whether the actual button press time (Tact) of the operation button 202 is shorter than the specified waiting time (Twait) for the start of the load swing suppression control. If the button press time (Tact) is longer than the waiting time (Twait) for the start of the load swing suppression control, the process proceeds to step S11; if the button press time (Tact) is shorter than the waiting time (Twait) for the start of the load swing suppression control, the process proceeds to step S12.

[0090] In addition, for example, when a target speed command value (Vtgt) for a load is generated based on a movement plan from a higher-level control system, the duration of the target speed command value (Vtgt) can be used as time (Tact) to perform the same action.

[0091] Step S11

[0092] If, in step S10, it is determined that the crane's movement time is longer than the waiting time (Twait) for the start of the load swing suppression control, then in step S11, the load swing suppression speed command value (Vsps) is sent as the speed command value (Vout) to the electric motor control device 300. When step S11 is executed, the process ends and waits until the next start time (timing).

[0093] Step S12

[0094] If, in step S10, it is determined that the crane's movement time is shorter than the waiting time (Twait) for the load sway suppression control to begin, then in step S12, it is determined whether the operation button 202 has been released, causing the load target speed command value (Vtgt) to decelerate. Alternatively, it can be determined whether the load target speed command value (Vtgt) generated based on the load movement plan has decelerated, based on signals other than the operation button 202, such as from the upper-level control system. If the load target speed command value (Vtgt) has decelerated, the process proceeds to step S11. On the other hand, if the load target speed command value (Vtgt) has not decelerated (acceleration state), the process proceeds to step S13. This determination is based on the load target speed command value (Vtgt) decelerating, but it can also be performed by directly detecting the OFF signal of the operation button 202.

[0095] Step S13

[0096] In step S13, operation button 202 is pressed, and since the crane has been moving for a long time and no micro-motion operation has been performed at this moment, the target lifting speed command value (Vtgt) is sent as the speed command value (Vout) to the electric motor control device 300. When step S13 is executed, the process ends and waits for the next start time.

[0097] based on Figure 9 This describes the action of the speed command value (Vout) after executing the above control steps. Additionally, in Figure 10 The value in the figure represents the time response of the horizontal moving speed and the amount of sway of the suspended weight in this embodiment.

[0098] Figure 9 (a) indicates the state when the crane has been moving for a long time and no micro-motion operation has been performed. When the operation button 202 is pressed at time (ts), the target speed command value (Vtgt) is sent to the electric motor control device 300 as a speed command value (Vout) until the load sway suppression control start waiting time (Twait) shown at time (tw) is reached. Then, when the load sway suppression control start waiting time (Twait) is reached at time (tw), the load sway suppression speed command value (Vsps) is sent to the electric motor control device 300 as a speed command value (Vout).

[0099] This process is repeated. During this process, the target speed command value (Vtgt) for the suspended load is output to prevent the speed command value (Vout) from becoming too large. For example, when implementing load sway suppression control, an excessively large load sway suppression speed command value (Vsps) is output to suppress load sway caused by the inertial force applied to the suspended load. Therefore, the target speed command value (Vtgt) for the suspended load is directly output at the initial stage of acceleration to prevent the speed command value (Vout) from becoming too large.

[0100] Moreover, it can be repeated any number of times. In step S10, if it is determined that the button press time (Tact) is longer than the waiting time (Twait) for the load swing suppression control to start, a load swing suppression speed command value (Vsps) is output. This suppresses the load swing.

[0101] Figure 9 (b) Indicates the situation where the crane has a short movement time and is in the state of micro-movement operation. When the operation button 202 (acceleration signal generation) is pressed at time (ts), the target speed command value (Vtgt) of the load swing suppression control is sent to the electric motor control device 300 as the speed command value (Vout) until the load swing suppression control start waiting time (Twait) shown at time (tw) is reached.

[0102] Next, during the waiting time (Twait) before the arrival time (tw), for example when the operation button 202 is released (deceleration signal is generated) and the target speed command value (Vtgt) of the load changes to deceleration, the load swing suppression speed command value (Vsps) for deceleration is sent to the electric motor control device 300 as the speed command value (Vout).

[0103] This process is repeated. During this process, the target speed command value (Vtgt) is output to prevent the speed command value (Vout) from becoming too large. This is as follows: Figure 9 As explained in (a). Therefore, it is possible to... Figure 10 As shown in the figure, the amount of load swing during the initial acceleration phase is made closer to the value indicated by the dashed line than the load swing suppression speed command value (Vsps).

[0104] Moreover, in the process During the processing, when the operation button 202 is released in step S12, the target speed command value (Vtgt) of the suspended load changes to deceleration. Here, when the target speed command value (Vtgt) of the suspended load begins to decelerate, the suspended load swings due to this deceleration.

[0105] Therefore, when deceleration is detected, the load sway suppression speed command value (Vsps) is output. Thus, as... Figure 10 As shown, the initial sway of the load during deceleration can be suppressed to a value smaller than the target speed command value (Vtgt) of the load (as shown by the dashed line). This helps to suppress the worsening of residual load sway when the crane's travel time is short or when micro-movements are performed.

[0106] Furthermore, it is preferable to adjust the control start waiting time based on the time constant of the suspended weight's oscillation. Therefore, the control start waiting time is changed according to the length of the wire rope. Besides changing the control start waiting time based on the wire rope length, it can also be changed by calculating the period of the suspended weight's oscillation based on the amount of oscillation.

[0107] In the crane of this embodiment described above, a brake is installed to maintain the horizontal moving device in a stopped position (during the stop period), but in Figure 1 Not illustrated. The brake operates when the speed command value (Vout) input to the electric motor control device 300 is below the brake operating speed (Vbrk), and the speed command value (Vout) becomes "0" after the brake operates.

[0108] In Patent Document 1, because the output load target speed command value (Vtgt) is output, the speed command value (Vout) becomes a triangular wave shape. When the speed command value (Vout) becomes "0", residual load swing may occur after the crane stops.

[0109] In this embodiment, because the target speed command value (Vtgt) for the load is output until deceleration begins, steep acceleration is avoided. However, when deceleration begins, the load sway suppression speed command value (Vsps) is output, which reduces the load sway caused by deceleration. Therefore, even if the speed command value (Vout) becomes "0" due to the brake being activated, residual load sway after the crane stops can be suppressed.

[0110] Example 2

[0111] Next, a second embodiment of the present invention will be described. Furthermore, for structures and operations identical to those in Embodiment 1 described above, repeated descriptions will be omitted where unnecessary. The second embodiment is characterized in that, after the control start waiting time described in the first embodiment, a brake operation waiting time is added.

[0112] Figure 11 This indicates the time variation of the horizontal movement speed and the amount of load swing under micro-motion operation, which is characteristic of the second embodiment and is characterized by a set brake operation waiting time. For example... Figure 11As shown, it is characterized by performing free run control during the brake's operating waiting time. The control that constitutes this feature will be explained below.

[0113] In typical cranes, the brake of the horizontal moving device operates when the speed command value (Vout) input to the electric motor control device 300 is below the brake operating speed value (Vbrk). The brake is, for example, an electromagnetic brake, which allows the horizontal moving device to stop locally when activated. Alternatively, a servo locking mechanism can be used in addition to an electromagnetic brake.

[0114] Moreover, when it is necessary to base on Figure 11 When the speed command value (Vout) causes the horizontal moving device to operate, due to the deceleration after the initial operation of the load sway suppression control, the speed command value (Vout) sometimes falls below the brake operating speed value (Vbrk), causing the brake to engage. Furthermore, the speed command value (Vout) is set to "0" after the brake engages. Therefore, it can be considered that the load sway suppression control, used to suppress load sway after brake engagement, is terminated, resulting in large residual load sway.

[0115] Therefore, in this embodiment, as Figure 11 As shown, after the waiting time for the load swing suppression control to start (which can be immediately after the waiting time or after a specified interval), the brake operation waiting time is increased to control the brake's operation. The following uses... Figure 12 , Figure 13 This control is described. Furthermore, the control flow continues... Figure 8 The control flow is executed.

[0116] <<Step S20>>

[0117] In step S20, it is determined whether the brake operating time (Tbstp) has been set. If the determination is successful and the brake operating time (Tbstp) has not been set, the process proceeds to step S21; if the determination is successful and the brake operating time (Tbstp) has been set, the process proceeds to step S23. This is the starting point for determining whether to activate the brake as described below.

[0118] Step S21

[0119] Because it was determined in step S20 that the brake operating time (Tbstp) was not set, the brake operating time is set in step S21. The setting of the brake operating time (Tbstp) is determined based on whether the target speed command value (Vtgt) is lower than the predetermined speed value (Vbsv).

[0120] When the target speed command value (Vtgt) is greater than the specified speed value (Vbsv), the process ends and waits until the next start time.

[0121] Step S22

[0122] In step S22, the current time (Tins) is set as the brake operating time (Tbstp). When the brake operating time (Tbstp) is set, proceed to step S23.

[0123] Step S23

[0124] In step S23, the time difference between the brake operating time (Tbstp) set in step S20 or S22 and the current time (Tins: the time elapsed since the time in step S22) is calculated, and it is determined whether this time difference is greater than 1 / 2. Figure 11 The indicator shows the brake operation waiting time (Tbwait).

[0125] In this step, if it is determined that the time difference is less than the brake working waiting time (Tbwait), proceed to step S24; if it is determined that the time difference is greater than the brake working waiting time (Tbwait), proceed to step S26.

[0126] Step S24

[0127] Because it is determined in step S23 that the time difference is less than the brake working waiting time (Tbwait), in step S24, it is determined whether the speed command value (Vout) output from the speed command value calculation device 100 is "negative" (reverse rotation direction). If it is determined to be "negative" (reverse rotation direction), the process proceeds to step S25. If it is not determined to be "negative" (reverse rotation direction), the process ends and waits until the next start-up time.

[0128] Step S25

[0129] In step S25, because the current state exists Figure 11 Within the brake operating waiting time (Tbwait), the electric motor control device 300 operates freely with inertial movement when the brake is open. Here, the induction motor can be configured to maintain its connection to the inverter output of the electric motor control device 300, but with zero torque. Therefore, inertial movement can be achieved without disconnecting the circuit, and load sway suppression control can be performed as needed.

[0130] If this is the case, the brake will not operate, thus suppressing large residual load sway and enabling load sway suppression control. When free-run control is performed in step S25, the process ends and waits until the next start time.

[0131] <<Step S26>>

[0132] In step S23, it is determined that the time difference is greater than the brake's working waiting time (Tbwait), thus becoming... Figure 11 The state after the brake operation waiting time (Tbwait).

[0133] Therefore, in step S26, it is determined whether the speed command value (Vout) output from the speed command value calculation device 100 is less than the brake operating speed value (Vbrake).

[0134] When it is determined that the speed command value (Vout) is less than the brake operating speed value (Vbrake), proceed to step S27 to activate the brake. When it is determined that the speed command value (Vout) is greater than the brake operating speed value (Vbrake), end the process and wait until the next start time.

[0135] Step S27

[0136] In step S27, the current state is Figure 12 The state after the brake operation waiting time (Tbwait) is reached, thus engaging the brake to maintain the position of the horizontal moving device. At this time, the load swing suppression control is stopped.

[0137] Furthermore, regarding the specified speed value (Vbsv) used in step S22 and the brake operating speed value (Vbrake) used in step S26, in this embodiment, the specified speed value (Vbsv) is set to a large value, but the specified speed value (Vbsv) and the brake operating speed value (Vbrake) can be the same value, or the speed value can be further set to "0".

[0138] Furthermore, it is preferable to adjust the brake waiting time (Tbwait) based on the time constant of the load's oscillation. Thus, the brake waiting time can be varied according to the length of the wire rope. Besides varying the brake waiting time based on the wire rope length, it can also be adjusted by calculating the period of the load's oscillation based on the amount of oscillation.

[0139] Figure 13 This indicates the time variation of the speed command value of the horizontal moving device and the amount of sway of the suspended load during micro-motion operation in the second embodiment. As shown... Figure 13As shown, after setting the control start waiting time of the first embodiment, a brake operation waiting time is set. Therefore, in the case of a micro-motion operation, as shown by the solid line, the brake operation waiting time is set shortly after deceleration. Therefore, during this brake operation waiting time, the brake does not operate, thus suppressing the generation of large residual load sway. Moreover, load sway suppression control can be performed during this brake operation waiting time.

[0140] In this way, the operation of the load sway suppression control will not stop due to the operation of the brake, thus reducing residual load sway. Furthermore, in this embodiment, it is performed simultaneously with the first embodiment, but it can also be performed independently.

[0141] Figure 14 This indicates the target speed command value for the suspended load when the wire rope length is long, the output of the adder 114 within the suspended load sway suppression control device 110 (suspended load sway suppression control output), and the output of the limiting processing device 115 (limited processing output). Additionally... Figure 15 This indicates the time variation of the speed command value of the horizontal moving device and the swing of the suspended load at this moment.

[0142] like Figure 14 As shown, in this case, when deceleration begins, the output of the load sway suppression control also becomes "negative" (reverse rotation direction). Therefore, when the deceleration after the initial start of the load sway suppression control reaches below the brake operating speed and the brake is engaged, the action used to suppress subsequent load swaying is stopped, resulting in a large residual load sway.

[0143] Therefore, when the brake operation waiting time is set as in the second embodiment, such as Figure 15 As shown, the action of the load sway suppression control based on the operation of the brake immediately after deceleration is not stopped, and residual load sway can be suppressed even when a control start waiting time is set.

[0144] Example 3

[0145] Next, based on Figure 16 The third embodiment of the present invention will be described below. Furthermore, structures and operations common to the embodiments described above will be omitted unless necessary.

[0146] The third embodiment is characterized in that the speed command value calculation device 100 includes: a model calculation device 111, which calculates the lifting model speed value (Vmdl) based on the speed command value (Vout) of the horizontal moving device input to the electric motor control device 300 and a predetermined crane model; a feedback control calculation device 112, which performs feedback control calculation based on the lifting model speed (Vmdl); a feedforward control calculation device 113, which performs feedforward control calculation based on the lifting target speed command value (Vtgt); an adder 114, which adds the output of the feedback control calculation device 112 and the output of the feedforward control calculation device 113; and a limitation processing device 115, which performs limitation processing on the output of the adder 114.

[0147] Even when the crane travel time is long, the residual load swing of the load can be reduced even if the switching device provided in the speed command value calculation device 100 of the first embodiment is omitted.

[0148] Furthermore, the present invention is not limited to the above-described embodiments and includes various modifications. The embodiments described above are detailed examples for the purpose of readily understanding the present invention and are not necessarily limited to having all the described structures. Additionally, a portion of the structure of one embodiment can be replaced with the structure of another embodiment, or the structure of another embodiment can be added to the structure of one embodiment. Other additions, deletions, and substitutions of structures can also be made to the structures of each embodiment.

[0149] Explanation of reference numerals in the attached figures

[0150] 1…crane, 2…rail, 3…bridge, 4…trolley, 5…wire rope, 6…hook, 7…cable, 8…lifting load, 100…speed command value calculation device, 110…lifting load swing suppression control device, 111…model calculation device, 112…feedback control calculation device, 113…feedforward control calculation device, 114…adder, 115…limiting processing device, 120…switching device, 200…operation input device, 201…operation terminal device, 202…operation button, 300…control device.

Claims

1. A crane, characterized in that, have: A hoisting device that moves a suspended load vertically by raising and lowering a wire rope; A horizontal moving device that is equipped with the hoisting device and allows the suspended weight to move in the horizontal direction; An operation input device for generating the target lifting speed command value; A speed command value calculation device that generates the speed command value of the horizontal moving device based on the speed command value of the suspended target; and An electric motor control device that drives and controls the horizontal movement device based on the speed command value. The speed command value calculation device has: The load swing suppression control device calculates the load swing suppression speed command value of the horizontal moving device for suppressing the swing of the load based on the target speed command value of the load and the length of the wire rope. and The switching device outputs the load swing suppression speed command value from the load swing suppression control device when the input time of the target load speed command value from the operation input device reaches a predetermined load swing suppression control start waiting time, or when the input time of the target load speed command value from the operation input device is shorter than the predetermined load swing suppression control start waiting time and the target load speed command value from the operation input device begins to decelerate; otherwise, it outputs the target load speed command value from the operation input device.

2. The crane according to claim 1, characterized in that: The waiting time for the start of the load swing suppression control can be varied at least according to the length of the wire rope.

3. The crane according to claim 2, characterized in that: The load swing suppression control device includes: a calculation device that performs a predetermined calculation using at least the target speed command value of the load, the speed command value from the switching device, and the length of the wire rope to obtain the load swing suppression speed command value that suppresses the swing of the load.

4. The crane according to claim 3, characterized in that: The computing unit of the suspended weight swing suppression control device has: The model calculation device is based on the speed command value output from the switching device and input to the electric motor control device, and the crane model calculation load model speed value; and The control calculation device calculates, based on the target speed command value of the suspended load and the speed value of the suspended load model, a speed command value for suppressing the swaying of the suspended load by the horizontal moving device. The parameters of the model calculation device and the control calculation device can be changed at least according to the length of the wire rope.

5. The crane according to claim 4, characterized in that: The control and calculation unit of the suspended weight swing suppression control device has: A feedback control calculation device that performs feedback control calculations based on the speed value of the suspended load model; A feedforward control calculation device that performs feedforward control calculations based on the target speed command value; An adder that adds the output of the feedback control arithmetic device and the output of the feedforward control arithmetic device; and A limiting processing device that limits the output of the adding device. The parameters of the feedforward control calculation device and the feedback control calculation device can be changed at least according to the length of the wire rope.

6. A crane, characterized in that, have: A hoisting device that moves a suspended load vertically by raising and lowering a wire rope; A horizontal moving device that is equipped with the hoisting device and allows the suspended weight to move in the horizontal direction; An operation input device for generating the target lifting speed command value; A speed command value calculation device that generates the speed command value of the horizontal moving device based on the speed command value of the suspended target; and An electric motor control device that drives and controls the horizontal movement device based on the speed command value. The speed command value calculation device If the elapsed time from when the target speed command value from the operation input device falls below a specified speed value is shorter than the specified brake operating waiting time, and the speed command value from the speed command value calculation device becomes negative, then the horizontal moving device shall be controlled to move freely by inertia. If the elapsed time is longer than the brake operating waiting time and the speed command value from the speed command value calculation device becomes lower than the brake operating speed value, braking control to maintain the position of the horizontal moving device is performed.

7. The crane according to claim 6, characterized in that: The brake's operating waiting time can be varied at least according to the length of the wire rope.

8. The crane according to claim 7, characterized in that: The speed command value calculation device includes: a calculation device that uses at least the target speed command value of the suspended weight, the speed command value, and the length of the wire rope to perform a prescribed calculation to obtain the speed command value for suppressing the swaying of the suspended weight.

9. The crane according to claim 8, characterized in that: The computing unit of the suspended weight swing suppression control device has: The model calculation device calculates the lifting speed value of the crane model based on the speed command value input to the electric motor control device and the crane model calculation value of the lifting load model; and The control calculation device calculates, based on the target speed command value of the suspended load and the speed value of the suspended load model, a speed command value for suppressing the swaying of the suspended load by the horizontal moving device. The parameters of the model calculation device and the control calculation device can be changed at least according to the length of the wire rope.

10. The crane according to claim 9, characterized in that: The control and calculation unit of the suspended weight swing suppression control device has: A feedback control calculation device that performs feedback control calculations based on the speed value of the suspended load model; A feedforward control calculation device that performs feedforward control calculations based on the target speed command value; An adder that adds the output of the feedback control arithmetic device and the output of the feedforward control arithmetic device; and A limiting processing device that limits the output of the adding device. The parameters of the feedforward control calculation device and the feedback control calculation device can be changed at least according to the length of the wire rope.

11. The crane according to any one of claims 6 to 10, characterized in that: The speed command value calculation device includes: A load sway suppression control device, which calculates a load sway suppression speed command value for the horizontal moving device to suppress the sway of the load based on the target speed command value of the load and the length of the wire rope; and The switching device outputs the load swing suppression speed command value from the load swing suppression control device when the input time of the load target speed command value from the operation input device reaches a predetermined control start waiting time, or when the load target speed command value from the operation input device begins to decelerate; otherwise, it outputs the load target speed command value from the operation input device.

12. A control method for a crane, wherein, The crane includes: a hoisting device that moves the load vertically by raising and lowering a wire rope; a horizontal moving device that moves the load horizontally by mounting the hoisting device; and an operation input device that generates a target speed command value for the load. A speed command value calculation device that generates a speed command value for the horizontal moving device based on the target lifting speed command value; and an electric motor control device that drives and controls the horizontal moving device based on the speed command value. The control method is characterized by: The speed command value calculation device Based on the target speed command value for the suspended load and the length of the wire rope, the swing suppression speed command value for the horizontal moving device, used to suppress the swing of the suspended load, is calculated. If the input time of the target speed command value for the load from the operation input device reaches the predetermined control start waiting time, or if the input time of the target speed command value for the load from the operation input device is shorter than the predetermined control start waiting time and the target speed command value for the load from the operation input device begins to decelerate, the target speed command value for the load swing suppression control device outputs the target speed command value for the load swing suppression. Otherwise, the target speed command value for the load from the operation input device is output.

13. A control method for a crane, wherein, The crane includes: a hoisting device that moves the load vertically by raising and lowering a wire rope; a horizontal moving device that moves the load horizontally by mounting the hoisting device; and an operation input device that generates a target speed command value for the load. A speed command value calculation device that generates a speed command value for the horizontal moving device based on the target lifting speed command value; and an electric motor control device that drives and controls the horizontal moving device based on the speed command value. The control method is characterized by: The speed command value calculation device If the elapsed time from when the target speed command value from the operation input device falls below a specified speed value is shorter than the specified brake operating waiting time, and the speed command value from the speed command value calculation device becomes negative, then the horizontal moving device shall be controlled to move freely by inertia. If the elapsed time is longer than the brake operating waiting time and the speed command value from the speed command value calculation device becomes lower than the brake operating speed value, braking control to maintain the position of the horizontal moving device is performed.

14. A crane, characterized in that, have: A hoisting device that moves a suspended load vertically by raising and lowering a wire rope; A horizontal moving device that is equipped with the hoisting device and allows the suspended weight to move in the horizontal direction; An operation input device for generating the target lifting speed command value; A speed command value calculation device that generates the speed command value of the horizontal moving device based on the speed command value of the suspended target; and An electric motor control device that drives and controls the horizontal movement device based on the speed command value. The speed command value calculation device has: A model calculation device that calculates the speed value of the lifting model based on the speed command value input to the electric motor control device and the crane model; A feedback control calculation device that performs feedback control calculations based on the speed value of the suspended load model; A feedforward control calculation device that performs feedforward control calculations based on the target speed command value; An adder that adds the output of the feedback control arithmetic device and the output of the feedforward control arithmetic device; and A limiting processing device that limits the output of the adding device. The parameters of the model calculation device, the feedforward control calculation device, and the feedback control calculation device can be changed at least according to the length of the wire rope.

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