Crane steady rest control method and crane steady rest control device

Abstract

To provide a swing stop control method of a crane and a swing stop control device of the crane, capable of improving swing restraining accuracy after stopping carrying of a suspending cargo.SOLUTION: A swing stop control method of a crane includes a step of transporting a suspended load to a target position by the crane, a step of acquiring a swing cycle and a maximum remaining swing angle after the transport is stopped, a step of determining a timing in an inching operation using the swing cycle and the maximum remaining swing angle, a step of determining an acceleration in the inching operation using the swing cycle and the maximum remaining swing angle, and a step of performing the inching operation by a predetermined operation amount at a predetermined swing angle when the maximum remaining swing angle is equal to or greater than a predetermined threshold value.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an anti-sway control method for a crane and an anti-sway control device for a crane. [Background technology]

[0002] When transporting a suspended load using a crane, in addition to transporting the load to its destination, anti-sway control is also required. When transporting a suspended load, the acceleration and deceleration of the traveling body cause the load to sway due to the action of inertia, which interferes with the loading and unloading operation. The simplest method for reducing the sway angle θ to zero is, for example, to physically install an anti-sway mast at the upper hoisting limit of the crane, but this has the issue of increasing the cost of installing the equipment. For this reason, various anti-sway controls have been proposed to reduce the sway angle θ to zero through software-based measures.

[0003] For example, Patent Document 1 discloses a technology for preventing sway by increasing the speed at a predetermined acceleration α, then running at a constant speed, and when approaching the end point, decelerating at a first-stage deceleration speed β1, running at a constant speed for a short period of time, and then decelerating to a stop at the second-stage deceleration speed.

[0004] Furthermore, Patent Document 2 discloses a technology that, in addition to the pattern control of Patent Document 1, memorizes the inching operation (inching operation) of the operator and repeats the operation at a timing calculated from the swing period of the suspended load, thereby improving the swing control performance over short distances where pattern control cannot be applied.

[0005] Furthermore, Patent Document 3 discloses the following control method in addition to the pattern control of Patent Document 1. That is, in Patent Document 3, the stopping pattern is compensated based on the deviation between the sway angular velocity pattern of the suspension rope predicted to occur when the trolley is controlled according to the stopping pattern and the actual sway angular velocity. Then, the target speed of the trolley is sequentially generated based on the compensated stopping pattern, thereby improving controllability against disturbances. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 57-4891 [Patent Document 2] Japanese Patent Application Publication No. 3-56396 [Patent Document 3] Japanese Patent Application Laid-Open No. 2017-165580 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the sway suppression control using the speed pattern disclosed in Patent Document 1 cannot suppress sway over short distances because it cannot guarantee acceleration at nT times the sway period. In addition, the sway suppression control disclosed in Patent Document 2 is vulnerable to disturbances and cannot eliminate sway caused by disturbances such as strong winds or sway in the initial state of the suspended load when starting to travel.

[0008] Here, Figure 4 shows the simulation results of the sway angle of the load when speed pattern control is performed with and without an initial sway angle. In Figure 4, the graph shown in (a) shows the acceleration of the crane, and the graph shown in (b) shows the sway angle of the crane when there is an initial sway angle and when there is no initial sway angle.

[0009] In the acceleration shown in Figure 4(a), the deceleration acceleration is applied for a period of time twice the sway period from the start of deceleration to the stop of the crane, and an acceleration command is given just enough to stop the crane. As a result, when there is no initial sway angle (solid line), the sway angle becomes zero when the crane stops, whereas when there is an initial sway angle (dashed line), the sway angle remains even after the crane stops. Therefore, as can be seen in Figure 4, the sway suppression control disclosed in Patent Documents 1 and 2 cannot eliminate the initial sway angle.

[0010] In addition, in the vibration suppression control disclosed in Patent Document 3, there is a problem that complex arithmetic processing is required in order to achieve both vibration damping in response to disturbances and positioning accuracy.

[0011] The present invention has been made in view of the above, and an object thereof is to provide a vibration damping control method for a crane and a vibration damping control device for a crane that can improve the vibration suppression accuracy after the suspension load stops being transported.

Means for Solving the Problems

[0012] In order to solve the above-described problems and achieve the object, a vibration damping control method for a crane according to the present invention includes a step of transporting a suspended load to a target position by the crane, a step of acquiring a vibration period and a maximum residual vibration angle after the transport stops, a step of determining a timing in the inching operation using the vibration period and the maximum residual vibration angle, a step of determining an acceleration in the inching operation using the vibration period and the maximum residual vibration angle, and a step of performing an inching operation with a predetermined operation amount at a predetermined vibration angle when the maximum residual vibration angle is greater than or equal to a predetermined threshold value.

[0013] In addition, the vibration damping control method for a crane according to the present invention, in the above invention, the step of performing the inching operation is performed according to the following inching pattern. When Δx≧abT 2 / 16, (a) When 0 < t < T / 4, an acceleration a is applied in the same direction as the vibration. (b) When T / 4 < t ≦ 3 / 4T, an acceleration -a is applied. (c) When 3 / 4T < t ≦ T, an acceleration a is applied. When Δx < abT 2 / 16, (a) When 0 < t ≦ tc, an acceleration a is applied in the same direction as the vibration. (b) When tc < t ≦ 2tc, an acceleration -a is applied. (c) When 2tc < t ≦ T - 2tc, the speed v = 0. (d) When T - 2tc < t ≤ T - tc, an acceleration of -a is applied. (e) When T - tc < t ≤ T, an acceleration of a is applied. However, Δx is the maximum residual swing amount after the conveyance stop, a is the acceleration [m / sec 2 , b is a constant obtained by experiment [-] (1 ≤ b ≤ 2), T is the swing period [sec] after the conveyance stop, t is the elapsed time [sec] from the conveyance stop, and tc is given by the following formula (1). [Number]

[0014] Further, the anti-sway control method for a crane according to the present invention further includes, in the above invention, a step of determining the acceleration time, the constant-speed movement time, and the deceleration time of the suspended load using the hoisting distance of the crane, the weight of the suspended load, and the natural period of the suspended load.

[0015] In order to solve the above-described problems and achieve the object, an anti-sway control device for a crane according to the present invention includes means for transporting a suspended load to a target position by a crane, means for acquiring the swing period and the maximum residual swing angle after the conveyance stop, means for determining the timing in the inching operation using the swing period and the maximum residual swing angle, means for determining the acceleration in the inching operation using the swing period and the maximum residual swing angle, and means for performing an inching operation with a predetermined operation amount at a predetermined swing angle when the maximum residual swing angle is greater than or equal to a predetermined threshold value.

[0016] Further, the anti-sway control device for a crane according to the present invention, in the above invention, the means for performing the inching operation operates according to the following inching pattern. When Δx ≥ abT 2 / 16, (a) When 0 < t < T / 4, an acceleration of a is applied in the same direction as the swing. (b) When T / 4 < t ≤ 3 / 4T, an acceleration of -a is applied. (c) When 3 / 4T < t ≤ T, an acceleration of a is applied. When Δx < abT 2In the case of / 16, (a) When 0 < t ≤ tc, an acceleration a is applied in the same direction as the swing. (b) When tc < t ≤ 2tc, an acceleration -a is applied. (c) When 2tc < t ≤ T - 2tc, the velocity v = 0. (d) When T - 2tc < t ≤ T - tc, an acceleration -a is applied. (e) When T - tc < t ≤ T, an acceleration a is applied. However, Δx is the maximum residual swing amount after the conveyance stop, a is the acceleration [m / sec 2 , b is a constant [-] (1 ≤ b ≤ 2) obtained by experiments, T is the swing period [sec] after the conveyance stop, t is the elapsed time [sec] from the conveyance stop, and tc is given by the following formula (1). [Number]

[0017] In addition, the swing suppression control device for a crane according to the present invention further includes means for determining the acceleration time, constant velocity movement time, and deceleration time of the suspended load using the hoisting distance of the crane, the weight of the suspended load, and the natural period of the suspended load in the above invention. [Advantages of the Invention]

[0018] According to the present invention, it is possible to improve the swing suppression accuracy after the conveyance stop of the suspended load. [Brief Description of the Drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a crane to which the swing suppression control method for a crane according to the embodiment is applied. [Figure 2] FIG. 2 is a flowchart showing the processing flow of the swing suppression control method for a crane according to the embodiment. [Figure 3] FIG. 3 is a diagram for explaining an example of the swing suppression control method for a crane according to the embodiment. [Figure 4]FIG. 4 is a diagram showing the simulation results of the sway angle of the suspended load during speed pattern control with and without the initial sway angle. DETAILED DESCRIPTION OF THE INVENTION

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A crane anti-sway control method and a crane anti-sway control device according to an embodiment of the present invention will be described with reference to the drawings.

[0021] (Crane anti-sway control device) FIG. 1 shows the configuration of a crane to which an anti-sway control method for a crane according to an embodiment is applied. Crane 1 is a crane capable of traversing and hoisting operations. Crane 1 is a so-called overhead crane that travels on a runway provided along a building. Crane 1 also includes a main body 11, a wire reel with a load sensor 12, a lifter 13, a gripping mechanism 14, an emitter 15, and a receiver 16.

[0022] A plurality of wire reels 12 with load sensors are provided inside the main body 11. The wire reels 12 with load sensors each have a built-in load sensor that detects a load. The specific configuration of the load sensor is not particularly limited, but a load cell or the like can be used, for example.

[0023] The lifter (slab lifter) 13 has a gripping mechanism 14 for gripping the load C. The specific configuration of the gripping mechanism 14 is not particularly limited, but for example, a plurality of gripping claws with adjustable opening can be used. In addition, the shape of the load C to be transported by the lifter 13 is also not particularly limited.

[0024] The emitter 15 and receiver 16 are displacement sensors that measure the distance between the main body 11 and the lifter 13. By using such a displacement sensor, it is possible to detect the relative phase shift of the lifter 13 with respect to the main body 11, i.e., the swing angle. The specific configuration of the displacement sensor is not particularly limited, but a beacon or the like can be used, for example. In the following description, the displacement sensor configured by the emitter 15 and receiver 16 will also be referred to as a "swing angle sensor."

[0025] The control device 2 is connected to the crane 1. The control device 2 is realized by a general-purpose information processing device such as a personal computer or a workstation. The control device 2 mainly includes a processor such as a CPU (Central Processing Unit) and a memory (main storage unit) such as a RAM (Random Access Memory) and a ROM (Read Only Memory).

[0026] The control device 2 functions as a means for transporting the load C to the target position using the crane 1, a means for acquiring the sway period and maximum residual sway angle after transport has stopped, and a means for determining the timing of the inching operation using the sway period and maximum residual sway angle. The control device 2 also functions as a means for determining the acceleration during the inching operation using the sway period and maximum residual sway angle, and a means for performing a predetermined movement amount and inching operation at a predetermined sway angle when the maximum residual sway angle is equal to or greater than a predetermined threshold. The control device 2 also functions as a means for determining the acceleration time, constant velocity movement time, and deceleration time of the load C, as necessary, using the hoisting distance of the crane 1, the weight of the load C, and the natural period of the load C. The method by which the control device 2 determines the inching pattern when performing the inching operation will be described later.

[0027] (Method for controlling crane sway) Fig. 2 shows the flow of processing for the anti-sway control method for a crane according to the embodiment. The anti-sway control method for a crane is mainly carried out by the control device 2. Of the steps shown in Fig. 2, steps S1 to S3 correspond to the sway suppression speed pattern control (speed pattern control) also carried out in the prior art (e.g., Patent Documents 1 to 3), and steps S4 to S10 correspond to the residual sway suppression control according to this embodiment.

[0028] First, when the control device 2 receives a command to transport the load C (step S1), it uses the same sway suppression speed pattern control as conventional (step S2) to transport the load C lifted by the crane 1 to the target position while suppressing the sway associated with transportation (step S3).

[0029] Next, the control device 2 acquires the time (swing period) from when the sway angle is 0 degrees until it reaches its maximum sway angle and the maximum residual sway angle using the sway angle sensor of the crane 1, and calculates the maximum residual sway amount Δx based on these (step S4). Next, the control device 2 compares the absolute value of the maximum residual sway amount Δx with a predetermined allowable value to determine whether or not residual sway suppression control is required (step S5).

[0030] The method for obtaining the maximum residual deflection angle is not particularly limited. For example, the absolute value of the measurement value of the deflection angle sensor can be calculated by subtracting the current measurement result from the previous measurement result, and the previous measurement result when the result is a negative value can be used as the maximum residual deflection angle. The deflection angle sensor can be, for example, a SIRRAH LS08. In addition to the deflection angle sensor, the maximum residual deflection angle can also be obtained by detecting the relative displacement difference between the main body 11 and the lifter 13 using an induction radio or a laser rangefinder. In addition to the above method, the maximum residual deflection angle can also be obtained by using the maximum absolute value of the deflection angle over a certain period of time, or by approximating the waveform with a formula and calculating the extreme value.

[0031] The maximum residual swing amount LsinΦ of the suspended load C during lowering (hereinafter referred to as "Δx") can be calculated from the value of the maximum residual swing angle Φ described above and the required lowering amount L at the crane lowering position. If the sum value Δx + Δy of this maximum residual swing amount Δx and the stop accuracy error Δy of the crane 1 exceeds the clearance between the crane center at the crane lowering position and other equipment, the lifter 13 including the suspended load C and the equipment will interfere during lowering. As a result, equipment damage troubles occur.

[0032] Therefore, when Δx + Δy exceeds the clearance between the crane center at the crane lowering position and other equipment in step S5, the control device 2 determines that the maximum residual swing amount Δx has exceeded the allowable value (No in step S5). And when it is determined that the residual swing suppression control has not been performed more than a predetermined number of times (No in step S6), the residual swing suppression control (steps S7, S8) is performed.

[0033] When the maximum residual swing amount Δx exceeds the allowable value, the control device 2 determines a suitable inching pattern according to the magnitude of the swing amount. Also, the control device 2 waits until the swing angle θ becomes 0 degrees (step S7), and performs an inching operation to the side that suppresses the residual swing angle in accordance with the timing when the swing angle θ becomes 0 degrees (step S8). Further, when the suspended load C swings in the reverse direction, the control device 2 performs an inching operation (equivalent to the reverse direction as before) to the side that suppresses the residual swing angle in accordance with the timing when the swing angle θ becomes 0 degrees again.

[0034] The inching pattern in the inching operation can be determined as follows according to the magnitude of the maximum residual swing amount Δx.

[0035] When Δx ≧ abT 2 / 16, (a) When 0 < t < T / 4, an acceleration a is applied in the same direction as the swing. (b) When T / 4 < t ≦ 3 / 4T, an acceleration -a (in the direction opposite to the acceleration a) is applied. (c) When 3 / 4T < t ≤ T, an acceleration a is applied (the speed becomes 0). Δx < abT 2 In the case of / 16, (a) When 0 < t ≤ tc, an acceleration a is applied in the same direction as the swing. (b) When tc < t ≤ 2tc, an acceleration -a is applied. (c) When 2tc < t ≤ T - 2tc, the speed v = 0. (d) When T - 2tc < t ≤ T - tc, an acceleration -a is applied. (e) When T - tc < t ≤ T, an acceleration a is applied. However, Δx is the maximum residual swing amount after the conveyance stop, a is the acceleration [m / sec 2 , b is a constant [-] obtained experimentally (1 ≤ b ≤ 2), T is the swing period [sec] after the conveyance stop, t is the elapsed time [sec] from the conveyance stop, and tc is the acceleration / deceleration time shown by the following formula (1). [Number]

[0036] At this time, the constant b [-] obtained experimentally means the moving amount of the crane that can remove the residual swing when performing one reciprocation in the forward and reverse directions during the swing period T of the suspended load C with the acceleration a of the crane 1 until the swing stops. Also, the moving amount of the crane 1 at that time is "2Δx / b".

[0037] When the maximum residual swing amount Δx ≥ abT 2 / 16, it means that the swing cannot be completely removed by one residual swing suppression control. In this case, during the swing period T of the suspended load C, the acceleration is constantly applied in the forward and reverse directions to move, thereby performing residual swing suppression as much as possible.

[0038] After performing this residual shake suppression control (steps S7 and S8), the process returns to step S4 to calculate the maximum residual shake amount Δx again, and if the maximum residual shake amount Δx exceeds the allowable value in step S5 (No in step S5), the residual shake suppression control is performed again using the same sequence (steps S7 and S8). By repeating this process, it becomes possible to suppress residual shake regardless of the magnitude of the residual shake angle.

[0039] On the other hand, the maximum residual runout Δx <abT 2 In the case of / 16, the residual swing can be removed by moving the crane 1 by "Δx / b" in both the forward and reverse directions during the swing period T of the load C. In this case, by moving the required movement amount Δx / b during the acceleration / deceleration time tc in both the forward and reverse directions, the "atc 2 =Δx / b”, that is, acceleration and deceleration must be performed within the time given by the above formula (1).

[0040] After performing this residual shake suppression control (steps S7 and S8), the process returns to step S4 to calculate the maximum residual shake amount Δx again, and if the maximum residual shake amount Δx exceeds the allowable value in step S5 (No in step S5), the residual shake suppression control is performed again using the same sequence (steps S7 and S8). By repeating this operation, it becomes possible to suppress residual shake regardless of the magnitude of the residual shake angle.

[0041] In order to prevent the residual shake suppression control from going into an infinite loop, if the control device 2 has performed the residual shake suppression control more than a predetermined number of times (Yes in step S6), it outputs an error and stops the control (step S9). Also, if the maximum residual shake amount Δx is equal to or less than the allowable value in step S5 (Yes in step S5), the control device 2 lowers the load C without performing the residual shake suppression control (step S10).

[0042] According to the anti-sway control method for a crane and the anti-sway control device for a crane according to the embodiment described above, it is possible to improve the accuracy of suppressing sway after transportation of the suspended load C has stopped.

[0043] (Example) An example of the anti-sway control method for a crane according to this embodiment will be described with reference to Fig. 3. As shown in Fig. 3, it can be seen that the sway amplitude can be suppressed to an allowable value or less by performing lateral travel control using speed pattern control and anti-sway inching (residual sway suppression control).

[0044] In Figure 3, (a) shows the crane's travel position, (b) shows the speed command (actual speed), (c) shows the travel swing width (actual value of the swing angle sensor), (d) shows the travel command for rightward movement (reverse direction), and (e) shows the travel command for leftward movement (forward direction).

[0045] In Figure 3, in the (1) speed pattern area, speed pattern control is performed to accelerate and decelerate for a specified time in accordance with the swing cycle T of the suspended load. As a result, the (c) swing angle sensor performance was reduced by approximately 84% from the maximum swing amount in the figure. However, it was confirmed that residual swing still existed.

[0046] Then, (2) based on the calculation results of the runout amount Δx, (3) anti-sway inching control was performed, and by inching in both the forward and reverse directions, it was confirmed that the remaining runout was reduced by 95% from the maximum runout amount shown in the figure, and by 69% compared to speed pattern control.In terms of the margin for the allowable value, it was confirmed that while the speed pattern control exceeded the allowable value by 60%, after anti-sway inching control, the runout amount was reduced to 50% of the allowable value.

[0047] From the above, it became clear that the runout width can be suppressed to within the allowable value by implementing lateral travel control using speed pattern control and anti-sway inching control. Specifically, in Fig. 3, the maximum runout amount was 500 mm, which was reduced to 80 mm after speed pattern control and to 25 mm after anti-sway inching control, achieving a runout reduction of 50% of the allowable value of 50 mm.

[0048] The anti-sway control method and anti-sway control device for a crane according to the present invention have been specifically described above using a description of the preferred embodiment and examples, but the spirit of the present invention is not limited to these descriptions and must be broadly interpreted based on the claims. Furthermore, it goes without saying that various changes and modifications based on these descriptions are also included in the spirit of the present invention. [Explanation of symbols]

[0049] 1 crane 11 Main unit 12 Wire reel with load sensor 13 Lifter 14 Gripping mechanism 15. Exit section 16 Receiving unit 2. Control device C. Suspended load

Claims

1. transporting the load to a target position by a crane; A step of acquiring a swing period and a maximum residual swing angle after transportation is stopped; determining timing for an inching operation using the swing period and the maximum residual swing angle; determining an acceleration during an inching operation using the swing period and the maximum residual swing angle; When the maximum residual swing angle is equal to or greater than a predetermined threshold value, performing an inching operation by a predetermined amount at a predetermined swing angle; A method for controlling an anti-sway of a crane, comprising:

2. 2. The anti-sway control method for a crane according to claim 1, wherein the inching operation step performs the operation according to the following inching pattern: Δx≧abT ２ In the case of / 16, (a) When 0<t<T / 4, acceleration a is applied in the same direction as the vibration. (b) When T / 4<t≦3 / 4T, apply acceleration -a. (c) When 3 / 4T<t≦T, give acceleration a. Δx<abT ２ In the case of / 16, (a) When 0<t≦tc, acceleration a is applied in the same direction as the vibration. (b) When tc<t≦2tc, give acceleration -a. (c) When 2tc<t≦T−2tc, the velocity v=0. (d) When T-2tc<t≦T-tc, apply acceleration -a. (e) When T-tc<t≦T, apply acceleration a. where Δx is the maximum residual vibration after the conveyance is stopped, and a is the acceleration [m / sec ２ ], b is a constant [-] (1≦b≦2) determined by experiment, T is the vibration period [sec] after transportation stops, t is the elapsed time [sec] from the stop of transportation, and tc is the following formula (1). [Equation 1]

3. 3. The anti-sway control method for a crane according to claim 1 or claim 2, further comprising the step of determining an acceleration time, a constant velocity movement time, and a deceleration time of the load using the hoisting distance of the crane, the weight of the load, and the natural period of the load.

4. a means for transporting the suspended load to a target position by a crane; A means for acquiring a swing period and a maximum residual swing angle after transportation is stopped; a means for determining timing for an inching operation using the swing period and the maximum residual swing angle; a means for determining an acceleration during an inching operation using the swing period and the maximum residual swing angle; a means for performing an inching operation by a predetermined amount at a predetermined swing angle when the maximum residual swing angle is equal to or greater than a predetermined threshold value; A crane anti-sway control device comprising:

5. 5. The anti-sway control device for a crane according to claim 4, wherein the inching operation means performs operation in the following inching pattern. Δx≧abT ２ In the case of / 16, (a) When 0<t<T / 4, acceleration a is applied in the same direction as the vibration. (b) When T / 4<t≦3 / 4T, apply acceleration -a. (c) When 3 / 4T<t≦T, give acceleration a. Δx<abT ２ In the case of / 16, (a) When 0<t≦tc, acceleration a is applied in the same direction as the vibration. (b) When tc<t≦2tc, give acceleration -a. (c) When 2tc<t≦T−2tc, the velocity v=0. (d) When T-2tc<t≦T-tc, apply acceleration -a. (e) When T-tc<t≦T, apply acceleration a. where Δx is the maximum residual vibration after the conveyance is stopped, and a is the acceleration [m / sec ２ ], b is a constant [-] (1≦b≦2) determined by experiment, T is the vibration period [sec] after transportation stops, t is the elapsed time [sec] from the stop of transportation, and tc is the following formula (1). [Equation 2]

6. 6. A crane sway prevention control device according to claim 4 or claim 5, further comprising means for determining an acceleration time, a constant velocity movement time, and a deceleration time of the load using the hoisting distance of the crane, the weight of the load, and the natural period of the load.

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