Crane and method of controlling a crane

Abstract

This invention provides a crane that reduces the increase in braking distance caused by load sway suppression control and improves operability. When calculating the speed command value of the horizontal moving device used to suppress load sway based on the target speed vpref(t) of the load and the sling length L, the transfer function from the target speed of the load to the speed command value of the horizontal moving device is given by ωc^2 / ωr^2·(s^2+2ζr·ωr·s+ωr^2) / (s^2+2ζc·ωc·s+ωc^2). Here, "ωc" and "ζc" are control parameters, "ωr=sqrt(g / L)" and "ζr=vl / (g / L)", "g" is the acceleration due to gravity, "L" is the distance from the sling rotation center to the center of gravity of the load, "vl" is the lifting speed, "^" represents a power, and "sqrt" represents the square root. Furthermore, ωr, ζr, ωc, and ζc satisfy the relationship of δ=ωc / ωr, ζc=δ·ζr / 2+sqrt((δ·ζr / 2)^2+1 / 2).

Description

Technical Field

[0001] This invention relates to a crane for suspending and transporting suspended loads and a method for controlling the crane. 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, there is an increasing number of inexperienced and unskilled operators driving (operating) cranes. Unskilled operators are particularly bad at anti-swaying operations to suppress the swaying of the load, which increases the risk of accidents such as collisions or jamming caused by the swaying of the load. In addition, it takes time for the swaying of the load to stop, thus increasing the operation time.

[0003] Therefore, as a technology for automatically suppressing the swaying of the suspended load in order to improve safety and work efficiency, the technologies shown in "Patent Document 1" and "Non-Patent Document 1" and "Non-Patent Document 2" are known, for example.

[0004] Patent Document 1 discloses a method for controlling the sway of a crane that includes a hoisting device that moves a load vertically by lifting and lowering a sling, a horizontal moving device that moves a load mounted on the hoisting device horizontally, a hoisting device suspended by a sling mounted on the horizontal moving device, and an operation input device for inputting a target speed of the load. The method involves calculating a model speed of the load based on the target speed of the load in the horizontal direction and a model of the crane, and calculating and controlling the speed command value of the horizontal moving device in a manner that makes the target speed of the load consistent with or close to the model speed.

[0005] In addition, Non-Patent Document 1 and Non-Patent Document 2 show a method for calculating and controlling the speed command value of a horizontal moving device in such a way that the target speed of the suspended weight is consistent with or close to the model speed using a controller designed according to the DMM method (Dual Model Matching method).

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2018-2391

[0009] Non-patent literature

[0010] Non-patent literature 1: Zhang, et al., Motion and vibration control of crane system based on IDCS length variation, Proceedings of the 54th Joint Conference on Automatic Control (2011)

[0011] Non-Patent Document 2: Mori, and four others, Sensorless Vibration Damping Control of a Horizontal Two-Axis Full-Scale Overhead Crane Based on Feedback Control Simulation, Proceedings of the 2016 USB Conference of the Dynamics and Design Division of the Japan Society of Mechanical Engineers (Japanese: Mori et al., Sensorless Vibration Damping Control of a Horizontal Two-Axis Full-Scale Overhead Crane Based on Feedback Control Simulation, Proceedings of the 2016 USB Conference of the Dynamics and Design Division of the Japan Society of Mechanical Engineers (2016)) Summary of the Invention

[0012] Problems to be Solved by the Invention

[0013] According to the above-mentioned prior art documents, without using a load swing detection sensor, even if the length of the suspension rope changes due to the hoisting operation, it is possible to suppress the load swing (residual load swing) after the trolley stops.

[0014] However, when performing the above control, new problems such as an increase in the distance to stop the trolley (braking distance) and a decrease in operability occur due to the control for suppressing the residual load swing.

[0015] The present invention is made in view of such problems, and an object thereof is to provide a crane and a control method for a crane that can reduce the increase in the braking distance caused by the load swing suppression control and improve the operability.

[0016] Technical Solution for Solving the Problems

[0017] To solve the above problems, an example of the present invention is a crane, which includes:

[0018] A hoisting device capable of moving a load in the vertical direction by raising and lowering a suspension rope;

[0019] A horizontal moving device installed on the hoisting device for moving the load in the horizontal direction;

[0020] An operation input device for inputting the target speed of the load;

[0021] A speed command value calculation device for generating a speed command value for the horizontal moving device; and

[0022] A control device for controlling the speed of the horizontal moving device according to the speed command value,

[0023] The crane is characterized in that:

[0024] The speed command value calculation device has a load swing suppression control device, and the load swing suppression control device outputs a speed command value for the horizontal moving device for suppressing the swing of the load according to the target speed of the load and the length of the suspension rope,

[0025] The transfer function G(s) of the load swing suppression control device from the target speed of the load to the speed command value of the horizontal moving device is given by the following relationship:

[0026] G(s)=ωc^2 / ωr^2·(s^2+2ζr·ωr·s+ωr^2) / (s^2+2ζc·ωc·s+ωc^2)

[0027] Where "ωc" and "ζc" are control parameters, "ωr = sqrt(g / L)" and "ζr = vl / (g / L)" are respectively, "g" is the acceleration due to gravity, "L" is the distance from the center of rotation of the sling to the center of gravity of the suspended load, "vl" is the lifting speed, "^" represents the power symbol, and "sqrt" represents the square root.

[0028] Furthermore, the relationships ωr, ζr, ωc, and ζc satisfy the relationships δ=ωc / ωr and ζc=δ·ζr / 2+sqrt((δ·ζr / 2)^2+1 / 2).

[0029] Invention Effects

[0030] According to the present invention, the increase in braking distance caused by the control of load swing suppression can be reduced, thereby improving operability. Attached Figure Description

[0031] Figure 1 This is a structural diagram showing the structure of the crane, which is the subject of this invention.

[0032] Figure 2 This is a block diagram illustrating the structure of the control module of the crane to which this invention is applied.

[0033] Figure 3 This is an explanatory diagram illustrating the target speed command value generated by the operation input device.

[0034] Figure 4 This is a schematic diagram of a crane.

[0035] Figure 5 This is an illustrative diagram showing an example of the time response of a crane without load sway suppression control.

[0036] Figure 6 It is a block diagram representing the structure of a control module in the prior art.

[0037] Figure 7 This is an explanatory diagram illustrating an example of the effect of existing technology.

[0038] Figure 8 This is a block diagram illustrating the structure of the control module of the present invention.

[0039] Figure 9This is an explanatory diagram illustrating an example of the effects of the present invention.

[0040] Figure 10 This is a block diagram illustrating the structure of the control module in the second embodiment of the present invention. Detailed Implementation

[0041] 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 of the technical concept of the present invention are also included within its scope.

[0042] Here, the present invention is effective for various types of cranes capable of moving a load horizontally, and can be applied not only to cranes that move a load both horizontally and longitudinally via trolleys and bridges (e.g., bridge cranes), but also to cranes that only move horizontally or longitudinally (e.g., ship unloaders). That is, the term "crane" as used below includes all types of cranes capable of moving a load horizontally.

[0043] Furthermore, for heavy objects transported by cranes (suspension loads), the lifting equipment used in this invention is not limited to any lifting device capable of suspending heavy objects, and its material and shape can be of any type. Therefore, as described above, the term "suspension equipment" is used as a general term for lifting devices used to suspend heavy objects. That is, "suspension equipment" includes not only so-called suspension ropes, but also chains, belts, wires, cables, lines, ropes, etc.

[0044] Example 1

[0045] Next, the structure and operation of the crane according to the first embodiment of the present invention will be described.

[0046] In the accompanying drawings, the same reference numerals are used for the same equipment (device, component), and descriptions of existing equipment are sometimes omitted in the following description.

[0047] Figure 1 This represents a schematic structure of a bridge crane. Furthermore, as stated above, the present invention is not limited to bridge cranes.

[0048] Figure 1 In this crane, 1 comprises a track 2 installed along the walls on both sides of a building (not shown), a bridge 3 that moves along the top surface of the track 2, and a trolley 4 that moves along the bottom surface of the bridge 3. Wheels driven by electric motors are installed on the bridge 3 and the trolley 4, allowing the bridge 3 and the trolley 4 to move.

[0049] Additionally, a winch (not shown) is installed at the lower part of the trolley 4 to raise or lower the sling 5, thereby raising or lowering the hook 6 at the front end of the sling 5. The load 8 is suspended directly or via the wire rope 7 from the hook 6, and the load 8 rises or falls as the hook 6 rises or falls.

[0050] 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 using a winch device. In this embodiment, horizontal movement is achieved by using the trolley 4 for lateral movement and the bridge 3 for longitudinal movement.

[0051] Figure 1 In 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 considered 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 horizontal movement performed by "traversing" and "traversing." Furthermore, in the following description, the movement of the suspended load refers to either or both of the movement of the trolley 4 (traversing) and the movement of the bridge 3 (traversing).

[0052] Figure 2 This refers to the control module of the crane in this embodiment. Additionally, Figure 2 To simplify the explanation, a crane 1 is shown moving horizontally through a trolley 4. Figure 2 The longitudinal movement via the bridge 3 is omitted. Furthermore, the drive components, such as the electric motor, used to move the trolley 4 and the bridge 3 are also omitted.

[0053] Figure 2 The control module of the crane is shown, consisting of a speed command value calculation unit 100 that calculates the speed command values ​​of the horizontal moving devices (bridge 3 and trolley 4) and a motor control unit 300. The speed command value 401 from the speed command value calculation unit 100 is sent to the motor control unit 300, which then provides power to the motors of the bridge 3 and trolley 4 corresponding to the speed command value 401.

[0054] The speed command value calculation device 100 is typically based on a general-purpose computer and consists of a microprocessor unit (MPU) 101 that performs calculations to generate speed command values ​​401 using built-in programs and data, a memory 102 that stores the aforementioned programs and data, and an input / output control unit 103 that receives data and signals from external sources and processes the signals output from the externally connected MPU 101. The MPU 101, memory 102, and input / output control unit 103 are connected by a bus 104 for exchanging signals and data. This structure is well known in computer systems.

[0055] The input / output control unit 103 is connected to an operation input device 200 that generates a target speed command value 400 for the suspended load. The operation input device 200 includes an operation terminal device 201 operated by the operator. The operation terminal device 201 is equipped with operation buttons 202 corresponding to the movement directions of the suspended load, namely "forward", "rear", "right", "left", "above" and "below". The target speed command value 400 for the suspended load is generated corresponding to the pressed operation button and output to the speed command value calculation device 100.

[0056] Figure 3 This example illustrates how the operation input device 200 generates a target speed command value 400 for the suspended load. At time (t1), when the operation button 202 is pressed (becomes ON), the target speed command value for the suspended load corresponding to the direction of the pressed operation button gradually increases. During the period when the operation button 202 is continuously pressed, a constant speed is maintained. At a subsequent time (t2), when the operation button 202 is released (becomes OFF), the target speed command value for the suspended load gradually decreases and eventually becomes "0".

[0057] For the speed command value calculation device 100, in addition to the target speed command value of the hoisting load given 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-level control system such as the production management system.

[0058] The motor control device 300 receives a speed command value 401 output from the speed command value calculation device 100 and controls the horizontal movement (lateral movement) speed of the vehicle 4. The specific structure of the motor control device 300 is not shown, but it can be constructed using a general-purpose computer and inverter circuit, similar to the speed command value calculation device 100. Furthermore, the motor control device 300 and the speed command value calculation device 100 can be housed in the same casing.

[0059] in addition, Figure 2While some details are omitted, the speed command value calculation device 100 not only outputs the speed command value for controlling the trolley 4, but also, in the case of longitudinal control, outputs the speed command value for controlling the horizontal (longitudinal) movement speed of the bridge frame 3. On the bridge frame 3 side, the horizontal (longitudinal) movement speed of the suspended load is controlled according to this speed command value.

[0060] Additionally, the speed command value calculation device 100 inputs the output of the sling length detector (not shown), which is the sling length.

[0061] Next, the method for suppressing the swaying of the suspended load (suspension sway) will be explained. In Figure 4 The diagram shows a schematic of the crane. Here, we take the transverse movement of trolley 4 as an example. The longitudinal movement of the bridge frame is the same; the oscillation of the load in the transverse and longitudinal directions can be considered as separate and independent oscillations.

[0062] according to Figure 4 The equation of motion for the crane (the sling 5 and the load 8 suspended on the trolley 4) is shown in the following equation.

[0063] L·x1”(t)+2vl·x1'(t)+g·x1(t)

[0064] +L·x0””t)=0…(1)

[0065] Here, "x0(t)" is the time function of the trolley's position, "x1(t)" is the time function of the load's swing (load swing), "L" is the distance from the center of rotation of the sling to the center of gravity of the load (swing length), "vl" is the lifting speed, and "g" is the acceleration due to gravity. Additionally, "'" indicates the time derivative, as is the case in the following formulas.

[0066] Then, by performing a Laplace transform on this relation, we obtain the following equation.

[0067] (s^2+2ζr·ωr·s+ωr^2)·X1(s)=s^2·X0(s)…(2)

[0068] Here, ωr = sqrt(g / L), ζr = vl / sqrt(g·L), "s" is the Laplace operator, "X0(s)" is the Laplace transform of the trolley position, and "X1(s)" is the Laplace transform of the sway of the suspended weight. Additionally, "^" represents exponentiation, and "sqrt" represents the square root, as is the case in the following formulas.

[0069] According to this relationship, the transfer function P(s) of the oscillation of the suspended weight X1(s) relative to the trolley velocity V0(s) (=s·X0(s)) is shown in the following equation.

[0070] P(s)=X1(s) / V0(s)=X1(s) / (s·X0(s))

[0071] =-s / (s^2+2ζr·ωr·s+ωr^2)…(3)

[0072] For relation (3), find the given... Figure 3 The target speed command value for the suspended load shown is the time response of the suspended load oscillation when the trapezoidal speed waveform is displayed. Here, the suspended load oscillation during acceleration is calculated, and the same can be done during deceleration / stopping. The target speed command value for the suspended load during acceleration, vpref(t), is given by the following formula.

[0073] vpref(t)=V·(u1(0)-u1(Ta))…(4)

[0074] Here, "V" is the constant speed of the car, "Ta" is the acceleration time, and "u1" is the unit ramp function.

[0075] When subjected to a Laplace transform, the following equation is obtained.

[0076] Vpref(s)=V / Ta·(1-exp(-s·Ta)) / s^2…(5)

[0077] Here, "Vpref(s)" is the Laplace transform of the target speed command value vpref(t). The target speed command value Vpref(s) is input to the motor control device 300 of the trolley 4, and the trolley 4 follows this speed command value.

[0078] That is, if we set V0(s) = Vpref(s), then the swing of the suspended weight X1(s) becomes as shown in the following formula.

[0079] X1(s)=P(s)·V0(s)

[0080] =-V·(1-exp(-s·Ta)) /

[0081] (s·Ta·(s^2+2ζr·ωr·s+ωr^2))…(6)

[0082] When the inverse Laplace transform is performed, the time response of the suspended weight oscillation during acceleration is obtained.

[0083] Figure 5 This is an example illustrating the time response of the trolley speed and the oscillation of the suspended load. Thus, when a trapezoidal wave speed command is given to trolley 4, the suspended load oscillates at an angular frequency ωr (frequency ωr / 2π) at the pole with the denominator of the transfer function P(s) being zero.

[0084] Next, the load sway suppression control device used to suppress the swaying of the load will be described. Figure 6 The diagram shows the structure with an added load sway suppression control device. The load sway suppression control device 110 is mounted in the speed command value calculation device 100, and generates a speed command value 401 for the trolley 4 output by the motor control device 300 to the trolley 4 based on the target speed command value 400 input from the operation input device 200. If the trolley 4 follows the input speed command value 401, that is, if the speed command value 401 of the trolley 4 is the same as the speed 402 of the trolley 4, then the transfer function G(s) of the trolley speed command value 401 relative to the target speed command value 400 can be set as described below.

[0085] To suppress the swaying of the suspended load, the numerator of the transfer function G(s) should have 1 / ωr^2·(s^2+2ζr·ωr·s+ωr^2) as a term that cancels out the zero denominator of the transfer function P(s). Furthermore, to ensure the tracking and stability of the trolley 4 towards the suspended load speed command value vpref(s), the denominator of the transfer function G(s) should have 1 / ωc^2·(s^2+2ζc·ωc·s+ωc^2) to the same degree as the numerator. Here, "ωc" and "ζc" are control parameters. Additionally, the control parameter "ωc" is set to a value where the speed command value of the horizontal moving device does not exceed the speed / acceleration limit.

[0086] Therefore, the transfer function G(s) from the target speed of the suspended weight to the speed command value of the horizontal moving device is expressed as shown in the following equation.

[0087] G(s)=ωc^2 / ωr^2·(s^2+2ζr·ωr·s+ωr^2) /

[0088] (s^2+2ζc·ωc·s+ωc^2)…(7)

[0089] According to the aforementioned prior art (Non-Patent Document 1, Non-Patent Document 2), the control parameters ωc and ζc are set to make the gain 0dB and the phase delay 0deg in the frequency band of the movement of the trolley 4.

[0090] Then, the trolley speed and the swing of the load under the condition of using the above transfer function G(s) for load swing suppression control are shown in the following formula.

[0091] V0(s)=G(s)·Vpref(s)…(8)

[0092] X1(s)=P(s)·V0(s)

[0093] =-V·(1-exp(-s·Ta)) / (s·Ta)·ωc^2 /

[0094] ωr^2 / (s^2+2ζc·ωc·s+ωc^2)…(9)

[0095] When the inverse Laplace transform is performed on the equation, the time response of the trolley speed and the swing of the suspended weight is obtained. Figure 7 An example of the time response of the obtained trolley speed and the swing of the load, with the trolley position relative to the position at the start of deceleration, is shown.

[0096] Such as Figure 7 As shown, the sway control suppresses the sway of the load after acceleration and deceleration / stop. However, considering the position of the trolley, the distance traveled (braking distance) from the start of deceleration until the trolley 4 stops increases compared to when no control is applied. Therefore, the trolley 4 travels a distance greater than the operator's expected braking distance (the existing braking distance without control), thus creating a problem of reduced operability.

[0097] In this embodiment, to reduce the increase in braking distance and improve operability, the control parameters ωc and ζc are set as follows. Here, we focus on the speed v01(t) of the suspended weight, which is calculated using the following formula.

[0098] v01(t)=v0(t)+x1'(t)…(10)

[0099] When the Laplace transform and inverse Laplace transform are performed on this equation, the following equation is obtained.

[0100] V01(s) = V0(s) + s·X1(s)

[0101] = (1 + s·P(s))·V0(s)

[0102] =V·(1-exp(-s·Ta))·ωc^2 /

[0103] (s^2·Ta·ωr^2)·(2ζr·ωr·s+ωr^2) /

[0104] (s^2+2ζc·ωc·s+ωc^2)…(11)

[0105] v01(t)=α1(t)+α2(t)+α3(t)+α4(t)…(12)

[0106] Here:

[0107] α1(t)=V / Ta·(u1(0)-u1(Ta))

[0108] α2(t)=2V / Ta·(ζr / ωr-ζc / ωc)·(u0(0)-u0(Ta))

[0109] α3(t)=-2V / Ta·(ζr / ωr-ζc / ωc)·(u0(0)·

[0110] exp(-ζc·ωc·t)·cos(sqrt(1-ζc^2)ωc·

[0111] t)-u0(Ta)·exp(-ζc·ωc(t-Ta))·

[0112] cos(sqrt(1-ζc^2)ωc(t-Ta)))

[0113] α4(t)=V / Ta(2ζc^2·ωr-2ζr·ζc·ωc-ωr) /

[0114] (sqrt(1-ζc^2)ωr·ωc)·(u0(0)·

[0115] exp(-ζc·ωc·t)·sin(sqrt(1-ζc^2)ωc·

[0116] t)-u0(Ta)·exp(-ζc·ωc(t-Ta))·

[0117] sin(sqrt(1-ζc^2)ωc(t-Ta))),

[0118] u0 is the unit ramp function.

[0119] Then, when considering the v01(t) term, α1(t) is the trolley speed command value itself, α2(t) and α3(t) are the swing speed of the load, and α4(t) is the excess speed that causes the increase in braking distance.

[0120] Therefore, in this embodiment, α4(t) is always made zero, and ωc and ζc are determined in a manner that satisfies the following equation. That is, the characteristic is that it is set to satisfy the following relationship.

[0121] V / Ta(2ζc^2·ωr-2ζr·ζc·ωc-ωr) /

[0122] (sqrt(1-ζc^2)ωr·ωc)=0...(13)

[0123] Then, the solution ζc of this equation becomes the following equation.

[0124] ζc=δ·ζr / 2+sqrt((δ·ζr / 2)^2+1 / 2)…(14)

[0125] Here, δ = ωc / ωr. Furthermore, ωc is set as the value at which the speed command for the horizontal moving device does not exceed the speed / acceleration limit, which is determined by the performance of the vehicle 4.

[0126] exist Figure 8 The structure is shown using the control parameters ωc and ζc determined by this invention. Furthermore, in... Figure 9 The diagram illustrates an example of the time response of trolley speed, load sway, and trolley position relative to the position at the start of deceleration, under the load sway suppression control of the present invention. The load sway suppression control of the present invention also suppresses load sway after acceleration and after deceleration / stopping. Furthermore, considering the trolley position, the present invention shortens the braking distance compared to the prior art, achieving more precise operability than before.

[0127] As described above, by determining the control parameters ωc and ζc for suppressing load sway, the braking distance can be shortened while suppressing load sway, thus improving operability. Furthermore, assuming that the lifting and lowering operations are short and the lifting speed has little impact on load sway, ζc can be set to ζc = sqrt(1 / 2) ≈ 0.71.

[0128] Alternatively, the lifting sway suppression control of the present invention can be applied to the composite lifting target speed command value, which is the result of combining the lifting target speed command value in the transverse direction and the lifting target speed command value in the longitudinal direction, or the lifting target speed command value in any direction. The resulting speed command value is then allocated as a speed command value in the transverse direction and a speed command value in the longitudinal direction to drive the trolley and the bridge.

[0129] Example 2

[0130] Next, regarding the second embodiment of the present invention, based on Figure 10 The following explanations will be provided. Furthermore, for structures and operations common to the above embodiments, repeated explanations will be omitted unless absolutely necessary.

[0131] Figure 10 This is a block diagram illustrating the structure of the control module in the second embodiment of the present invention. In the first embodiment, it is envisioned that the speed of the vehicle 4 follows the speed command value, that is, the speed of the vehicle 4 is consistent with the speed command value.

[0132] However, when the trolley 4 and bridge 3 are large, or when the weight of the load is large, there may be a situation where the speed of the trolley 4 does not follow the speed command value. In this case, the transfer function G2(s) of the trolley speed 402 relative to the target speed command value 400 of the load, including the motor control device 300 and the trolley 4, has the characteristic of suppressing load sway.

[0133] That is, the numerator has 1 / ωr^2·(s^2+2ζr·ωr·s+ωr^2) as a term that cancels out the zero denominator of the transfer function P(s). To ensure the trolley's tracking and stability towards the target speed command value of 400, the denominator should have 1 / ωc^2·(s^2+2ζc·ωc·s+ωc^2) in the same order as the numerator. Here, as mentioned above, "ωc" and "ζc" are control parameters.

[0134] Therefore, the transfer function G2(s) can be set as shown in the following equation.

[0135] G2(s)=ωc^2 / ωr^2·(s^2+2ζr·ωr·s+ωr^2) /

[0136] (s^2+2ζc·ωc·s+ωc^2)…(15)

[0137] The value of ζc is determined by the relation (14) in Example 1. ωc is set as the value of the speed command of the horizontal moving device not exceeding the speed / acceleration limit, which is determined by the performance of the trolley 4.

[0138] Therefore, the transfer function G(s) of the speed command value 401 relative to the target speed command value 400 can be set as the following formula, which includes the inverse characteristic of the transfer function DM(s) = D(s)·M(s) from the speed command value 401 of the trolley to the speed 402.

[0139] G(s)=G2(s) / DM(s)…(16)

[0140] Here, D(s) is the transfer function of the motor control device, and M(s) is the transfer function of the trolley.

[0141] As mentioned above, even when the trolley is large or the load is heavy, and the trolley speed is inconsistent with the speed command value, it can still shorten the braking distance and improve operability while suppressing the swing of the load.

[0142] Furthermore, the present invention is not limited to the above-described embodiments, but includes various modifications. The above embodiments are described in detail for ease of understanding of the present invention and are not limited to having all the structures described. In addition, a part of the structure of one embodiment can be replaced with the structure of another embodiment, and the structure of another embodiment can be added to the structure of one embodiment. For the structures of each embodiment, other structures can also be added, deleted, or replaced.

[0143] Explanation of reference numerals in the attached figures

[0144] 1…crane, 2…rail, 3…bridge, 4…trolley, 5…sling, 6…hook, 7…wire rope, 8…lifted load, 100…speed command value calculation device, 110…lifted load swing suppression control device, 200…operation input device, 300…motor control device, 400…lifted load target speed, 401…trolley speed command value, 402…trolley speed.

Claims

1. A crane, comprising: A winch device that can move a suspended load vertically by raising and lowering slings; A horizontal moving device installed on the winch for moving the suspended load in the horizontal direction; An operation input device for inputting the target speed of the suspended weight; A speed command value calculation device that generates the speed command value of the horizontal moving device; and A control device that controls the speed of the horizontal moving device according to the speed command value of the horizontal moving device. The crane is characterized in that: The speed command value calculation device includes a load sway suppression control device, which outputs a speed command value for the horizontal moving device to suppress the sway of the load based on the target speed of the load and the length of the sling from the rotation center of the sling to the center of gravity of the load. The transfer function G(s) of the load swing suppression control device from the target speed of the load to the speed command value of the horizontal moving device is given by the following relationship: Where "ωc" and "ζc" are control parameters, "g" is the acceleration due to gravity, "L" is the distance from the center of rotation of the sling to the center of gravity of the suspended load, and "vl" is the lifting speed. Furthermore, the relationships ωr, ζr, ωc, and ζc satisfy δ = ωc / ωr. The relationship.

2. The crane as described in claim 1, characterized in that: Treat ζr as 0, and make ζc = 3. A crane, comprising: A winch device that can move a suspended load vertically by raising and lowering slings; A horizontal moving device installed on the winch for moving the suspended load in the horizontal direction; An operation input device for inputting the target speed of the suspended weight; A speed command value calculation device that generates the speed command value of the horizontal moving device; and A control device that controls the speed of the horizontal moving device according to the speed command value of the horizontal moving device. The crane is characterized in that: The speed command value calculation device includes a load sway suppression control device, which outputs a speed command value for the horizontal moving device to suppress the sway of the load based on the target speed of the load and the length of the sling from the rotation center of the sling to the center of gravity of the load. The transfer function G(s) of the load swing suppression control device from the target speed of the load to the speed command value of the horizontal moving device is given by the following relationship: Where "ωc" and "ζc" are control parameters, "g" represents the acceleration due to gravity, "L" represents the distance from the center of rotation of the sling to the center of gravity of the suspended load, "vl" represents the lifting speed, DM(s) = D(s)·M(s) is the transfer function from the speed command value of the horizontal moving device to the actual speed, D(s) is the transfer function of the control device, and M(s) is the transfer function of the horizontal moving device. Furthermore, the relationships ωr, ζr, ωc, and ζc satisfy δ = ωc / ωr. The relationship.

4. A method for controlling a crane, wherein the crane comprises: A winch device that can move a suspended load vertically by raising and lowering slings; A horizontal moving device installed on the winch for moving the suspended load in the horizontal direction; An operation input device for inputting the target speed of the suspended weight; A speed command value calculation device that generates the speed command value of the horizontal moving device; and A control device that controls the speed of the horizontal moving device according to the speed command value of the horizontal moving device. The crane control method is characterized by: The speed command value calculation device calculates the speed command value of the horizontal moving device used to suppress the swaying of the suspended weight based on the target speed of the suspended weight and the length of the sling from the rotation center of the sling to the center of gravity of the suspended weight. The transfer function G(s) from the target speed of the suspended weight to the speed command value of the horizontal moving device is given by the following relationship: Where "ωc" and "ζc" are control parameters, "g" is the acceleration due to gravity, "L" is the distance from the center of rotation of the sling to the center of gravity of the suspended load, and "vl" is the lifting speed. Furthermore, the relationships ωr, ζr, ωc, and ζc satisfy δ = ωc / ωr. The relationship.

5. A method for controlling a crane, wherein the crane comprises: A winch device that can move a suspended load vertically by raising and lowering slings; A horizontal moving device installed on the winch for moving the suspended load in the horizontal direction; An operation input device for inputting the target speed of the suspended weight; A speed command value calculation device that generates the speed command value of the horizontal moving device; and A control device that controls the speed of the horizontal moving device according to the speed command value of the horizontal moving device. The crane control method is characterized by: The speed command value calculation device calculates the speed command value of the horizontal moving device used to suppress the swaying of the suspended weight based on the target speed of the suspended weight and the length of the sling from the rotation center of the sling to the center of gravity of the suspended weight. The transfer function G(s) from the target speed of the suspended weight to the speed command value of the horizontal moving device is given by the following relationship: Where "ωc" and "ζc" are control parameters, "g" represents the acceleration due to gravity, "L" represents the distance from the center of rotation of the sling to the center of gravity of the suspended load, "vl" represents the lifting speed, DM(s) = D(s)·M(s) is the transfer function from the speed command value of the horizontal moving device to the actual speed, D(s) is the transfer function of the control device, and M(s) is the transfer function of the horizontal moving device. Furthermore, the relationships ωr, ζr, ωc, and ζc satisfy δ = ωc / ωr. The relationship.

Images