Crane and crane control method

Abstract

The present invention provides a crane with high safety that can reduce the braking distance while suppressing the weight swing generated when the crane is stopped. The crane has a speed command generation unit that generates a moving speed command of a horizontal moving device and a crane control unit that moves the horizontal moving device according to the speed command. The speed command generation unit generates a deceleration pattern (v1) and an acceleration / deceleration pattern (v2). In the deceleration pattern, deceleration is performed from the moment a stop action start signal is input, and in the acceleration / deceleration pattern, acceleration / deceleration is performed to offset the weight swing (x01) generated by the superposition of the weight swing (x1) generated when the horizontal moving device is driven by the deceleration pattern (v1). From the start of the stop action, the horizontal moving device is driven according to the deceleration pattern (v1), and the horizontal moving device is driven according to the acceleration / deceleration pattern (v2) so that the moment when the weight swing (x01) has the largest swing amount coincides with the center moment of the acceleration / deceleration pattern (v2).

Description

Technical Field

[0001] The present invention relates to a technique for controlling the motion of a crane for suspending and transporting a load, and more particularly to a crane, a crane control device, a crane control method, and a program for controlling a crane. Background Art

[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 installed, there are more and more cases of inexperienced operators driving (operating) cranes. In the crane operation performed by inexperienced operators, there is a risk of misoperation due to misjudgment of the position and height of obstacles, failure to notice surrounding obstacles, lack of skill in predicting the crane's movements such as the swing of the load, and unfamiliarity with crane operation. Therefore, in the crane operation performed by inexperienced operators, accidents such as collision and entrapment of the load with obstacles are more likely to occur than in the crane operation performed by skilled operators.

[0003] As one of the countermeasures to prevent accidents, there is a technology disclosed in Patent Document 1. Patent Document 1 discloses, as a control method for stopping a crane while suppressing the swing of a load, that when the action of stopping the crane is started, a shift operation or mechanical braking is first performed, and then one or more reverse shift operations or mechanical braking are performed at a timing after 1 / 2 of the swing cycle, or one or more reverse shift operations or mechanical braking are performed at a timing after 1 / 4 of the swing cycle.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 8-324960 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In the method disclosed in Patent Document 1, after deceleration by shift operation or mechanical braking, the shift (triangular wave speed pattern) is operated one or more times to suppress the swing of the load, but it is not possible to stop the load reliably with one operation, and as a result, it is not possible to expect a reduction in the braking distance. In view of this, it is required to stop the crane quickly and safely, that is, to suppress the swing of the load when an instantaneous change such as stopping occurs, and to shorten the braking distance.

[0009] Here, when the crane speed is changed, the time to reach the target speed or the time or moving distance for the speed change to be within a certain range is in a trade-off relationship with the size of the weight swing. That is, when the ratio of the change in the crane speed is increased, the above-mentioned time or moving distance becomes shorter, but the weight swing becomes larger. In particular, when the speed is changed suddenly, this problem becomes more significant. For example, as an example of speed change, when the crane is stopped, the braking distance from the trolley to the stop is short, but a large weight swing occurs. In order to reduce the weight swing, the speed change time (for example, the deceleration time) can be extended, or a control for suppressing the weight swing can be applied. However, in this case, although the weight swing can be suppressed, there is a problem of a longer braking distance.

[0010] The present invention has been made in view of such a problem, and an object of the present invention is to provide a technology for controlling the operation of a crane with higher safety, which can reduce the braking distance and time while suppressing the swing of the suspended load.

[0011] Technical solutions to solve problems

[0012] In order to solve the above-mentioned problem, in the present invention, a second speed pattern is generated to cancel out the "superimposed weight swing" (control means control within a certain range of target speed or speed change) caused by the weight swing at the start of the crane control and the weight swing caused by the first speed pattern of the crane control, and the crane operation is controlled using the acceleration and deceleration pattern. As an example, a crane includes a horizontal moving device that moves a weight suspended by a wire rope in a horizontal direction, a speed command generation unit that generates a speed command for controlling the horizontal moving device, and a crane control unit that controls the speed of the horizontal moving device according to the speed command, wherein the speed command generation unit generates a first speed pattern and a second speed pattern as the speed command, wherein in the first speed pattern, the speed is changed from the speed at the start of the speed change of the horizontal movement to a predetermined speed, and in the second speed pattern, acceleration and deceleration are performed to cancel out the third weight swing caused by the superimposition of the first weight swing at the start of the speed change and the second weight swing caused by the driving of the first speed pattern, and the crane control unit controls the horizontal moving device according to the generated first speed pattern and the second speed pattern.

[0013] Furthermore, the present invention also includes a control method for the above-mentioned crane and a program for executing the control method and controlling the crane.

[0014] In addition, here, the term "wire rope" is defined not only to mean a wire rope but also various tools such as chains, lines, ropes, belts, cables, etc. that can be used to suspend heavy objects.

[0015] Effects of the Invention

[0016] According to the present invention, the swing of the load caused by the speed change can be offset or reduced with fewer acceleration and deceleration times, so the distance to the target speed can be shortened while suppressing the swing of the load, and the safety of the crane can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a diagram showing a mechanism in an example of a crane that is a target of the present invention.

[0018] Figure 2 It is a figure which shows the structure of the crane which concerns on Example 1 of this invention.

[0019] Figure 3 This is a diagram showing the speed pattern generated in Example 1.

[0020] Figure 4 This is a diagram showing the processing flow of the speed command generating unit of the crane according to the first embodiment.

[0021] Figure 5 This is a diagram for explaining an operation example of the first embodiment.

[0022] Figure 6 It is a figure which shows the structure of the crane which concerns on Example 2 of this invention.

[0023] Figure 7 It is a figure which shows the structure of the crane which concerns on Example 3 in this invention. DETAILED DESCRIPTION

[0024] Hereinafter, several embodiments of the crane according to the present invention will be described with reference to the drawings.

[0025] Here, the present invention is effective for various cranes that can move a load in the horizontal direction. That is, the present invention is a technology that can be applied not only to cranes that use a trolley to move a load horizontally and vertically (e.g., bridge cranes), but also to cranes that only move horizontally or vertically (e.g., ship unloaders) or so-called mobile cranes. That is, in this specification, the term "crane" includes all types of cranes that can move a load in the horizontal direction. In addition, horizontal also includes curved movement of the arm of a mobile crane, etc. That is, it includes movement that may cause the load to swing due to movement.

[0026] In addition, for heavy objects (hanging weights) transported by cranes, they are suspended and transported by wire ropes or chains, and the present invention refers to any tool that can be used to suspend heavy objects, regardless of the material and shape. Therefore, as mentioned above, the term "wire rope" in this specification is recorded as a general term for tools used to suspend heavy objects.

[0027] That is, the "wire rope" includes not only the so-called steel wire rope, but also chains, belts, wires, cables, lines, ropes, etc.

[0028] <Example 1>

[0029] use Figures 1 to 5 , a crane according to Embodiment 1 of the present invention will be described. In each figure, the same equipment (device) is denoted by the same reference numeral, and the description of the existing equipment may be omitted in the description of subsequent figures.

[0030] Figure 1 It is a diagram showing the outline of the mechanism of a bridge crane. In addition, as mentioned above, the present invention is not limited to a bridge crane.

[0031] Figure 1 In the figure, the crane 1 is composed of a track 2 provided along the walls of both sides of a building (not shown), a bridge 3 moving on the top surface of the track 2, and a trolley 4 moving along the bottom surface of the bridge 3. A hoist (elevator) not shown is provided at the bottom of the trolley 4, and the wire rope 5 is wound up or down by the hoist, thereby raising or lowering the hook 6 at the front end of the wire rope 5. The hook 6 suspends a load 8 directly or via a cable 7, and the load 8 is raised or lowered as the hook 6 is raised or lowered. That is, the crane 1 can move the load 8 in the horizontal direction by the horizontal movement of the bridge 3 (hereinafter referred to as "vertical") and the horizontal movement of the trolley 4 (hereinafter referred to as "horizontal"), and can raise or lower the load 8 in the vertical direction (up and down direction) by the hoist.

[0032] In this embodiment, the horizontal movement is performed by using the trolley 4 for transverse movement and the bridge 3 for longitudinal movement (travel). Figure 1 In the embodiment, the trolley 4 and the bridge 3 are equivalent to the horizontal moving device. Since the present invention is related to the action of moving the load in the horizontal direction, the following description of the embodiment 1 of the present invention is centered on the action of horizontal movement by horizontal and vertical movement. Therefore, in the description of the following embodiment, the movement of the load means either or both of the movement of the driving trolley 4 (horizontal movement) and the movement of the driving bridge 3 (vertical movement).

[0033] Figure 2 It is a figure which shows the structure of the crane in Example 1 of this invention. Figure 2 In order to simplify the description, the crane 1 is shown to move horizontally by the trolley 4, and the longitudinal movement by the bridge 3 is omitted in the figure. In addition, the driving parts such as the motor for moving the trolley 4 and the bridge 3 are omitted.

[0034] Figure 2In the figure, 10 is a speed command generating unit that generates a speed pattern and the like to control the horizontal moving device (bridge 3 and trolley 4) in order to move the hanging weight 8 to the target position, and an example of using a general-purpose computer is shown here. 101 is an MPU (microprocessing unit) that uses built-in programs and data to perform calculations such as generating a speed pattern. 102 is a memory that stores its programs and data. 103 is an input / output control unit that inputs data and signals from the outside and outputs the signals and the like after the MPU has calculated and processed them to the outside. 104 is a bus for transmitting signals and data between the components in the speed command generating unit 10. 12 is a crane control unit that inputs the speed pattern output from the speed command generating unit 10 and controls the horizontal movement (traverse) speed of the trolley 4. The crane control unit 12 outputs a control signal corresponding to the input speed pattern to the trolley 4. In addition, the crane control unit 12 can also make the speed command generating unit 10 have its function and output a control signal from the speed command generating unit 10.

[0035] In addition, although Figure 2 Although omitted in the figure, the speed command generating unit 10 outputs not only a speed pattern for controlling the trolley 4, but also a speed pattern for controlling the horizontal movement (longitudinal) speed of the bridge 3 when performing longitudinal control. On the bridge 3 side, the horizontal movement (longitudinal) speed of the hanging weight is controlled according to the speed pattern. In addition, the output of the wire rope length detector not shown in the figure, that is, the wire rope length L0, is input to the speed command generating unit 10, and the speed Vs at the start time of the stop action is input from the speed detector not shown in the figure. In addition, when the wire rope length L0 and the speed Vs do not change, these data can be stored in the memory 102. In addition, 9 represents an obstacle. The obstacle 9 does not always exist in the transportation route of the hanging weight, but it is assumed that there is a possibility of its existence.

[0036] In addition, in this specification, the deceleration and stop of the crane are described as an example, but each embodiment can also be applied to control to a target speed such as acceleration or deceleration to a speed other than a stop speed. In this case, the speed at the start of the deceleration is the speed at the start of the control. In addition, the deceleration start time may be inputted by the speed detector or may be a predicted value based on the control.

[0037] Next, for Figure 2 The details of the crane control contents are explained. Figure 2 In the embodiment of the present invention, when the operator indicates the moving direction of the hanging weight by using the operation input device 100, the speed instruction generating unit 10 generates a speed instruction for moving the bridge 3 and the trolley 4 in the direction corresponding to the indicated moving direction. The crane control unit drives the bridge 3 and the trolley 4 according to the generated speed instruction, so that the hanging weight 8 moves in the horizontal direction (in this case, in the horizontal direction).

[0038] When the movement in the horizontal direction (horizontal or vertical) is to be stopped, the operator instructs the speed command generation unit 10 to issue a stop operation start signal 11 using the operation input device 100. For example, a button corresponding to the movement direction is arranged in the operation input device 100. Then, when the operator presses the button corresponding to the desired movement direction when starting the movement and releases the button when stopping the movement, the stop operation start signal 11 as a trigger for starting the stop operation is input to the speed command generation unit 10 when the button is released. Alternatively, the stop operation start signal 11 may be input from a separately provided stop button or an external device.

[0039] Figure 3 The figure is a speed pattern generated by the speed command generator 10 when the stop operation start signal 11 is input. When the stop operation start signal 11 is input, first, the bridge and carriage are driven in the first speed pattern v1 which decelerates the speed from Vs at the start of the stop operation by a time length T1.

[0040] Then, in order to offset the swing of the weight at the start of the stop action and the swing of the weight caused by driving at v1, the second speed mode v2 is driven after Tw from the start of the stop action, with a time length T2 and a maximum speed Vdmax for acceleration and deceleration. These speed modes are obtained according to the relationship described below. Among them, the speed mode can be any mode that represents the change of speed.

[0041] First, the transfer function P(s) from the crane speed command to the load swing amount is given by the following formula.

[0042] P(s)=-s / (s^2+wr^2)……(Mathematical formula 1)

[0043] Here, wr is the angular frequency of the weight swing, which is calculated according to wr=2*π / Tc based on the swing period Tc of the weight. Alternatively, it can be calculated according to wr=sqrt(g / L) (g: gravitational acceleration) based on the distance L from the rotation center of the wire rope to the center of gravity of the weight. Among them, L is calculated by adding the distance ΔL from the hook position to the center of gravity of the weight suspended by the wire to the length L0 of the wire rope. ΔL varies depending on the weight and the wire used, but can be measured by a distance sensor installed on the trolley, or input by the operator and stored in the memory 102 in advance.

[0044] The weight swing x0(t) at the start of the stopping action is given by the following equation.

[0045] x0(t)=A0*sin(wr*t+θ0)……(Formula 2)

[0046] Here, assuming that the weight swing amount at the start of the stopping action is x0(0) and the weight swing speed is v0(0), A0 and θ0 are as follows.

[0047] A0=sqrt(x0(0)^2+(v0(0) / wr)^2)……(Mathematical formula 3)

[0048] θ0=atan((v0(0) / wr) / x0(0))……(Formula 4)

[0049] When the first speed pattern v1 is given by a function v1(t) related to time t, the load swing x1(t) generated when the trolley is driven according to v1(t) can be obtained by performing a Laplace transform on v1(t) to obtain V1(s), and performing an inverse Laplace transform on X1(s) = P(s)*V1(s), as given by the following formula.

[0050] x1(t)=A1*sin(wr*t+θ1)……(Formula 5)

[0051] Here, when v1(t) is assumed to decelerate at a constant deceleration rate, A1 and θ1 are as follows.

[0052] A1=2*Vs*sin(T1*wr / 2) / (T1*wr^2)……(Mathematical formula 6)

[0053] θ1=-T1*wr / 2……(Formula 7)

[0054] Here, Vs is the speed of the car when the stopping action starts, and T1 is the deceleration time.

[0055] When the second speed pattern v2 is given by a function v2(t) related to time t, the load swing x2(t) generated when the trolley is driven according to v2(t) can be obtained by performing a Laplace transform on v2(t) to obtain V2(s), and performing an inverse Laplace transform on X2(s) = P(s)*V2(s), as given by the following formula.

[0056] x2(t)=A2*sin(wr*t+θ2)……(Formula 8)

[0057] Here, when v2(t) is set to a trapezoidal wave, A2 and θ2 are as follows.

[0058] A2=-4*Vdmax*(cos(r*T2*wr / 2)-cos(T2*wr / 2)) / ((1-r)*T2*wr^2)

[0059] ……(Mathematical formula 9)

[0060] θ2=π / 2-Tw*wr-T2*wr / 2……(Mathematical formula 10)

[0061] Here, r is the upper / lower base of the trapezoidal wave.

[0062] In order to suppress the weight swing after stopping, the weight swing x01(t) obtained by superimposing x0(t) and x1(t) can be offset by x2(t).

[0063] x01(t) is given by the following formula.

[0064] x01(t)=A01*sin(wr*t+θ01)……(Formula 11)

[0065] Here, A01 and θ01 used in Mathematical Formula 11 are as follows.

[0066] A01=sqrt(2*Vs^2+A0^2*T1^2*wr^4-2*Vs^2*cos(T1*wr)-2*A0*T1*Vs*wr^2*sin(θ0)+2*A0*T1*Vs*wr^2*sin(θ0+T1*wr)) / (T1*wr^2)

[0067] ……(Mathematical formula 12)

[0068] θ01=atan((-Vs+Vs*cos(T1*wr)+A0*T1*wr^2*sin(θ0)) / (A0*T1*wr^2*cos(θ0)+Vs*sin(T1*wr)))……(Mathematical formula 13)

[0069] In order to cancel x01(t) with x2(t), the phases of x01(t) and x2(t) can be matched and the amplitudes can be canceled. Thus, θ01=θ2 and A01=-A2 can be set.

[0070] According to θ01=θ2, the following formula can be obtained.

[0071] Tw+T2 / 2=(π / 2-θ01) / wr……(Formula 14)

[0072] Therefore, x01(t) at the center time (t=Tw+T2 / 2) of v2(t) is expressed as follows.

[0073] x01(Tw+T2 / 2)=A01*sin(π / 2)……(Formula 15)

[0074] This means that it is sufficient to make the time when x01(t) is maximum coincide with the center time of v2(t).

[0075] According to A01=-A2, the following formula can be obtained.

[0076] Vdmax=1 / 4*A01*(1-r)*T2*wr^2 / (cos(r*T2*wr / 2)-cos(T2*wr / 2))

[0077] ……(Mathematical formula 16)

[0078] From this formula, T2, Vdmax, and r can be obtained as follows.

[0079] First, when the set time T of T2 and the set speed V of Vdmax are given, r is determined as follows. If it is assumed that T2*wr / 2 is small, Vdmax can be approximated as shown in the following equation.

[0080] Vdmax=2*A01 / (1+r) / T2……(Mathematical formula 17)

[0081] Therefore, r is determined as shown in the following formula.

[0082] r=2*A01 / T / (k*V)……(Mathematical formula 18)

[0083] Here, k is a correction coefficient that takes into account the influence of the approximation. The rigorous solution of Vdmax is calculated using Equation 16 based on the determined r.

[0084] Furthermore, when the set speed V of Vdmax and the set acceleration α of the trapezoidal wave acceleration are given, T2 and r can be determined as follows: Assuming that T2*wr / 2 is small, the acceleration can be obtained as shown in the following equation.

[0085] α=Vdmax / ((1-r)*T2 / 2)

[0086] =4*A01 / (1-r^2) / T2^2……(Formula 19)

[0087] Therefore, T2 and r are determined as shown in the following formula.

[0088] T2=A01 / (k*V)+(k*V) / α……(Mathematical formula 20)

[0089] r=2*α*A01 / (α*A01+(k*V)^2)-1……(Mathematical formula 21)

[0090] Based on the determined T2 and r, the rigorous solution of Vdmax is calculated using Equation 16.

[0091] Furthermore, when r is set to 0, that is, a triangular wave is formed, and a set speed V of Vdmax is given, T2 is determined as follows. When r=0, Vdmax is expressed as follows.

[0092] Vdmax=1 / 8*A01*T2*wr^2 / sin(T2*wr / 4)^2……(Mathematical formula 22)

[0093] If it is assumed that T2*wr / 4 is small, Vdmax can be approximated as shown in the following equation.

[0094] Vdmax=2*A01 / T2……(Mathematical formula 23)

[0095] Therefore, T2 is determined as shown in the following formula.

[0096] T2=2*A01 / (k*V)……(Mathematical formula 24)

[0097] Here, k is a correction coefficient that takes into account the influence of approximation. A strict solution of Vdmax is calculated using Equation 22 based on the determined T2.

[0098] In addition, when r is set to 0 and a set acceleration α of a trapezoidal wave acceleration is given, T2 and Vdmax can also be determined as shown below. The acceleration can be obtained as shown in the following formula.

[0099] α=Vdmax / (T2 / 2)

[0100] =1 / 4*A01*wr^2 / sin(T2*wr / 4)^2……(Mathematical formula 25)

[0101] Therefore, T2 is determined as shown in the following formula.

[0102] T2=4 / wr*asin(1 / 2*sqrt(A01*wr^2 / α))……(Mathematical formula 26)

[0103] Vdmax is calculated using Formula 22 based on the determined T2.

[0104] The starting time Tw of v2(t) can be calculated using the following formula.

[0105] Tw=(π / 2-θ01) / wr-T2 / 2……(Mathematical formula 27)

[0106] In the case where Tw<0 in this formula, the drive based on v2(t) must be started before the stop action begins, so it cannot be realized. In this case, since x01(t) is a periodic function with an angular period of 2π, the moment when the weight swings the most after one cycle can be made consistent with the center moment of v2(t). Therefore, Tw is determined by the following formula.

[0107] Tw=((2*n+1 / 2)*π-θ01) / wr-T2 / 2……(Mathematical formula 28)

[0108] Here, n is 0 or 1.

[0109] Based on the above, the start time Tw and duration T2 of the second speed pattern v2, the maximum speed Vdmax, and the upper and lower bases r of the trapezoidal wave can be determined.

[0110] In addition, when the speed Vs at the start of the stop action is extremely low, T1 is approximately 0. In this case, since the weight swing x01(t) obtained by superimposing the weight swing x0(t) at the start of the stop action and the weight swing x1(t) caused by the first speed pattern is only x0(t), the amplitude A01 and phase θ01 of x01(t) can be regarded as the amplitude A0 and phase θ0 of x0(t).

[0111] In order to shorten the braking distance, it is preferred to reduce the duration T1 of the first speed mode v1(t) and the duration T2 of the second speed mode v2(t). To this end, it is preferred to make the deceleration of v1(t), the setting value V of the maximum speed of v2(t), and the setting value α of the acceleration as large as possible according to the performance of the bridge and the trolley.

[0112] Figure 4 2 is a diagram showing a processing flow of the speed command generating unit 10. The details of the processing will be described below.

[0113] In S01, the amplitude A0 and phase θ0 of the weight swing amount x0(t) at the start of the stop action are calculated from the weight swing amount x0(0) and the weight swing speed v0(0) at the start of the stop action using Mathematical Formula 3 and Mathematical Formula 4. In addition, if the bridge and trolley speed Vs at the start of the stop action is extremely low and A0 is less than the allowable value of the weight swing amount, the subsequent calculations may be omitted and the machine may be stopped.

[0114] In S02, based on A0, θ0, Vs, the duration T1 of the first speed pattern v1, and the angular frequency wr of the weight swing, the amplitude A01 and θ01 of the weight swing x01 obtained by superimposing x0 and the weight swing x1 generated by the v1 drive are calculated using equations 12 and 13. At this time, when Vs is at an extremely low speed, the v1 drive is not performed (T1=0), so that A01=A0 and θ01=θ0.

[0115] In S03, based on A01 and wr, and setting the upper / lower base r of the trapezoidal wave to 0, that is, setting the maximum speed setting value V of the second speed mode v2 of the triangular wave, use Mathematical Formula 24 and Mathematical Formula 22 to calculate the duration T2 of v2 and the maximum speed Vdmax.

[0116] In S04, T2 obtained in S03 is compared with a threshold value T2s=2*((π / 2-θ01) / wr-T1). If T2>T2s, there is a possibility that T2 can be shortened by setting r>0, so parameter calculation is performed to define the maximum speed and duration.

[0117] In S05, Vdmax is set to V, T2 is set to T2s, and Vdmax and r are obtained using Math 17 and Math 18. When the obtained trapezoidal wave acceleration is equal to or less than the maximum acceleration, it is considered that the drivable trapezoidal wave has been determined and the process proceeds to S10.

[0118] In S06 , it is determined whether the acceleration exceeds the maximum acceleration αmax. If so, parameter calculation is performed to define the acceleration so that the acceleration becomes equal to or less than αmax.

[0119] In S07, the set value of the acceleration is set to αmax, and T2 and Vdmax are calculated using Math. 26 and Math. 22.

[0120] In S08, it is determined whether the acceleration of the triangular wave is below the allowable value (minimum allowable acceleration αmin). If below the allowable value, T2 may be shortened by setting r>0, so parameter calculation is performed to define the maximum speed and acceleration.

[0121] In S09, Vdmax is set to V, acceleration is set to αmin, and T2, r, and Vdmax are calculated using Math. 20, Math. 21, and Math. 16.

[0122] In S10, the start time Tw is calculated using the equation 28. First, the calculation is performed by setting n=0, and when Tw<0, the calculation is performed again by setting n=1.

[0123] When calculating the parameters of the speed pattern as described above, the time length is shortened by using a trapezoidal wave when the time length is long when a triangular wave is used, so that the swing of the load can be suppressed and the time until stopping and the braking distance can be shortened.

[0124] Figure 5 This is a diagram for explaining the operation of the first embodiment, showing the time transition of the trolley speed and the amount of swing of the hanging weight from the top. Figure 5 It can be seen that the deceleration starts according to the first speed mode from the start of the stop action when the stop action start signal 11 is input. After that, the vehicle is driven according to the second speed mode, i.e., the trapezoidal wave speed instruction, thereby using the trapezoidal wave speed instruction to offset the swing of the weight caused at the start of the stop action and due to deceleration, and successfully suppressing the swing of the weight after the vehicle stops. In addition, since the vehicle can be stopped with a single trapezoidal wave, the braking distance can be shortened compared to the method of performing multiple operations.

[0125] As described above, according to the first embodiment, the swing of the load caused by deceleration can be offset by a single acceleration / deceleration, and the braking distance can be reduced while suppressing the swing of the load, thereby improving the safety of the crane.

[0126] In addition, the above embodiment describes the case where the crane is stopped, but the swing of the load can also be suppressed in the same manner when the speed is changed to any speed. In addition, the first speed mode and the second speed mode can also overlap, that is, Tw <T1。

[0127] <Example 2>

[0128] Next, a crane according to a second embodiment of the present invention will be described. However, repeated descriptions of points common to the above-described embodiment will be omitted. Figure 6 2 is a diagram showing the structure of a crane in Example 2. Figure 2 The major difference of the embodiment 1 shown is that Figure 6 The weight swing amount acquisition device for acquiring the swing amount and swing speed of the weight is provided. In the speed command generation of the above embodiment, the amplitude A0 and phase θ0 of the weight swing x0 at the start of the stop action are used, which can be obtained by using Mathematical Formulas 3 and 4 based on the weight swing amount x0(0) and the weight swing speed v0(0) at the start of the stop obtained by the weight swing amount acquisition device.

[0129] The weight swing amount acquisition device is a device for obtaining the swing amount and swing speed of the weight. The weight swing amount acquisition device in this embodiment is composed of a weight swing amount detector 13 for measuring the swing amount of the weight, and a weight swing speed calculation device for calculating the swing speed of the weight based on the measured weight swing amount. The weight swing amount detector 13 can be realized by, for example, observing (measuring) the swing of the hook 6 or the weight 8 using a camera or a three-dimensional laser distance sensor installed downward on the trolley. In addition, the weight swing speed calculation device performs, for example, differential calculation or pseudo-differential calculation on the measured weight swing amount. In this embodiment, the weight swing speed calculation device is not individually provided, but is constituted as a function of the speed instruction generation unit 10.

[0130] In addition, the weight swing amount acquisition device can be provided with a weight swing amount estimation device for estimating the weight swing amount and the weight swing speed, and the weight swing amount and the weight swing speed can be obtained by estimation based on the angular frequency wr of the weight swing and the speed command of the bridge and the trolley. Therefore, the weight swing amount acquisition device can also directly detect the weight swing amount without the weight swing amount detector 13. The angular frequency wr can be estimated based on the wire rope length L0. The function of the weight swing amount estimation device can also be configured to be calculated in the speed command generating unit 10.

[0131] The calculation of the weight swing amount and weight swing speed is, when the speed command of the bridge and the trolley is vt(t) and the weight swing amount is x(t), VT(s) and X(s) after Laplace transformation can be calculated using the following formula.

[0132] X(s)=P(s)*VT(s)……(Mathematical formula 29)

[0133] Therefore, the weight swing amount estimation device can estimate the weight swing amount by performing a filtering operation on vt(t) given by the transfer function P(s), and can estimate the weight swing speed by differentiating the obtained weight swing amount.

[0134] As described above, according to the second embodiment, the swing of the load caused by deceleration can be offset by a single acceleration / deceleration, and the braking distance can be reduced while suppressing the swing of the load, thereby improving the safety of the crane.

[0135] <Example 3>

[0136] Next, a crane according to a third embodiment of the present invention will be described. However, repeated descriptions of the contents common to the above-described embodiments will be omitted.

[0137] Figure 7 1 is a diagram showing the structure of a crane according to Embodiment 3 of the present invention. In this embodiment, an obstacle detector 14 is provided for detecting obstacles 9 around the hanging weight 8, the trolley 4, and the bridge 3. In addition, a collision judgment device 15 is provided, which receives the detection signal of the obstacle detector 14, judges whether there is a danger of collision between the obstacle 9 and any one of the hanging weight 8, the trolley 4, and the bridge 3, and outputs a stop operation start signal 11 to the speed instruction generating unit 10 when judging that there is a danger of collision.

[0138] The obstacle detector 14 can detect obstacles around the hanging weight 8 by observing the surroundings of the hanging weight 8 using a camera or a three-dimensional laser distance sensor installed downward on the trolley 4, for example. The collision judgment device 15 quickly outputs a stop action start signal 11 when predicting that the detected obstacle collides with the hanging weight. When the speed command generation unit 10 receives the stop action start signal 11, it generates the same speed pattern as the above-mentioned embodiment. That is, it generates a first speed pattern that decelerates from the speed at the start of deceleration to the first deceleration end speed, and a second speed pattern that performs acceleration and deceleration to offset the hanging weight swing generated when the above-mentioned horizontal moving device is driven according to the above-mentioned first speed pattern. Then, the generated speed pattern is output to the crane control unit 12, and the crane control unit 12 controls the speed of the bridge 3 and the trolley 4 to stop the crane. This control action can prevent the collision and clamping accidents between the hanging weight and the obstacle.

[0139] In addition, for example, by measuring the distance to a wall or a blocker, or other cranes running on the same track using a length measuring sensor installed on the trolley 4 or the bridge 3, it is possible to predict a collision between the crane and a wall or a blocker, or other cranes. If a stop operation start signal is quickly output to stop the crane when these situations are predicted, collisions and jamming accidents between the crane and a wall or a blocker, or other cranes can be prevented.

[0140] According to the crane of the third embodiment of the present invention described above, the swing of the load caused by deceleration can be offset by one acceleration and deceleration, so the braking distance can be reduced while suppressing the swing of the load, and the safety of the crane can be improved. Furthermore, collision and entrapment accidents can be prevented, and the safety of the crane can be further improved.

[0141] In addition, according to each embodiment taking the stop control as an example, the swing of the load caused by deceleration can be offset or reduced by one acceleration or deceleration, so the braking distance can be reduced while suppressing the swing of the load, and the safety of the crane can be improved.

[0142] In addition, the present invention is not limited to the above-mentioned embodiments, and includes various modified examples. For example, the above-mentioned embodiments are described in detail in order to explain the present invention in an easy-to-understand manner, and are not limited to all the structures that must be described. In addition, a part of the structure of a certain embodiment can be replaced with the structure of other embodiments, and the structure of other embodiments can be added to the structure of a certain embodiment. For the structure of each embodiment, other structures can be added, deleted, and replaced. In particular, the control of the crane is not limited to stopping, and can be applied to deceleration or acceleration to any speed (target speed). This situation includes keeping the target speed fixed within a specified range. In addition, the braking distance is the moving distance until the target speed.

[0143] Description of Reference Numerals

[0144] 1...crane, 2...track, 3...bridge, 4...trolley, 5...wire rope, 6...hook, 7...cable, 8...load, 9...obstacle, 10...speed instruction generating unit, 11...stop action start signal, 12...crane control unit, 13...load swing amount detector, 14...obstacle detector, 15...collision judgment device.

Claims

1. A crane comprising a horizontal moving device for horizontally moving a load suspended by a wire rope in a horizontal direction, a speed command generating unit for generating a speed command for controlling the horizontal moving device, and a crane control unit for controlling the speed of the horizontal moving device according to the speed command, wherein: The speed instruction generation unit generates a first speed pattern and a second speed pattern as the speed instruction, wherein: In the first speed mode, the speed at the start of the speed change of the horizontal movement is changed to a specified speed, and in the second speed mode, acceleration and deceleration are performed to offset the third weight swing caused by the superposition of the first weight swing at the start of the speed change and the second weight swing caused by the drive of the first speed mode. The crane control unit controls the horizontal moving device according to the first speed pattern from the start of the speed change, and controls the horizontal moving device so that the moment when the swing amount of the third hoisting weight is the largest coincides with the center moment of the second speed pattern, thereby controlling the horizontal moving device according to the generated first speed pattern and the second speed pattern.

2. The crane according to claim 1, characterized in that: The speed command generating unit uses a deceleration pattern for decelerating and stopping the horizontal movement of the crane as the first speed pattern.

3. The crane according to claim 1 or 2, characterized in that: The speed instruction generating unit calculates the start time, duration and maximum speed of the control in the second speed mode based on the amplitude, phase and angular frequency corresponding to the length of the wire rope of the third hoisting weight swing, the speed of the crane at the start of the speed change, and the time of the speed change of the first speed mode to generate the first speed mode.

4. The crane according to claim 3, characterized in that: The speed instruction generating unit calculates the amplitude and phase of the first weight swing based on the swing amount, swing speed and angular frequency in the first weight swing, and calculates the amplitude and phase of the third weight swing based on the calculated amplitude, phase and angular frequency of the first weight swing and the deceleration time of the first speed mode, i.e., the deceleration mode.

5. The crane according to claim 3, characterized in that: The speed command generating unit generates a second speed pattern showing a trapezoidal wave as the second speed pattern.

6. The crane according to claim 5, characterized in that: The speed command generating unit generates, as the first speed pattern, a first speed pattern in which the speed change of the horizontal movement is accelerated or decelerated at a certain ratio. The trapezoidal wave satisfies the following conditions when the starting time is Tw, the duration is T2, the maximum speed is Vdmax, the upper base / lower base of the trapezoidal wave is r, the angular frequency is wr, the amplitude of the third hanging weight swing is A01, and the phase is θ01 (n is 0 or 1): θ01=(2*n+1 / 2)*π-Tw*wr-T2*wr / 2 A01=-4*Vdmax*(cos(r*T2*wr / 2)-cos(T2*wr / 2)) / ((1-r)*T2*wr^2).

7. The crane according to claim 1 or 2, characterized in that: It also has a weight swing acquisition unit for acquiring the swing amount and swing speed of the weight, The speed command generating unit generates the speed command using the weight swing amount and the weight swing speed.

8. The crane according to claim 7, characterized in that: The load swing acquisition unit estimates the load swing amount and the load swing speed based on an angular frequency of the load swing or the angular frequency obtained from the length of the wire rope and the speed command of the crane.

9. The crane according to claim 1 or 2, characterized in that: Also includes: an obstacle detection unit for detecting obstacles to the hanging load and the crane; and A collision judgment unit judges whether there is a risk of collision between the obstacle detected by the obstacle detection unit and at least one of the hanging load and the crane, and outputs a stop operation start signal to the speed instruction generation unit to start a stop operation when there is a risk of collision.

10. A crane control method for controlling a crane, wherein the crane comprises a horizontal moving device for horizontally moving a load suspended by a wire rope in a horizontal direction, a speed command generating unit for generating a speed command for controlling the horizontal moving device, and a crane control unit for controlling the speed of the horizontal moving device according to the speed command, wherein: The speed instruction generation unit generates a first speed pattern and a second speed pattern as the speed instruction, wherein: In the first speed mode, the speed at the start of the speed change of the horizontal movement is changed to a specified speed, and in the second speed mode, acceleration and deceleration are performed to offset the third weight swing caused by the superposition of the first weight swing at the start of the speed change and the second weight swing caused by the drive of the first speed mode. The crane control unit controls the horizontal moving device according to the first speed pattern from the start of the speed change, and controls the horizontal moving device so that the moment when the swing amount of the third hoisting weight is the largest coincides with the center moment of the second speed pattern, thereby controlling the horizontal moving device according to the generated first speed pattern and second speed pattern.

11. The crane control method according to claim 10, characterized in that: The speed command generating unit uses a deceleration pattern for decelerating and stopping the horizontal movement of the crane as the first speed pattern.

12. The crane control method according to claim 10 or 11, characterized in that: The speed instruction generating unit generates the first speed mode by calculating the start time, duration and maximum speed of the control in the second speed mode based on the amplitude, phase and angular frequency corresponding to the length of the wire rope of the third hoisting weight swing, the speed of the crane at the start of the speed change, and the time of the speed change of the first speed mode.

13. The crane control method according to claim 12, characterized in that: The speed instruction generating unit calculates the amplitude and phase of the first weight swing based on the swing amount, swing speed and angular frequency in the first weight swing, and calculates the amplitude and phase of the third weight swing based on the calculated amplitude, phase and angular frequency of the first weight swing and the deceleration time of the first speed mode, i.e., the deceleration mode.

14. The crane control method according to claim 12, characterized in that: The speed command generating unit generates a second speed pattern showing a trapezoidal wave as the second speed pattern.

15. The crane control method according to claim 14, characterized in that: The speed command generating unit generates a first speed pattern in which the speed change of the horizontal movement is accelerated or decelerated at a certain ratio as the first speed pattern, The trapezoidal wave satisfies the following conditions when the starting time is Tw, the duration is T2, the maximum speed is Vdmax, the upper base / lower base of the trapezoidal wave is r, the angular frequency is wr, the amplitude of the third hanging weight swing is A01, and the phase is θ01 (n is 0 or 1): θ01=(2*n+1 / 2)*π-Tw*wr-T2*wr / 2 A01=-4*Vdmax*(cos(r*T2*wr / 2)-cos(T2*wr / 2)) / ((1-r)*T2*wr^2).

16. The crane control method according to claim 10 or 11, characterized in that: The crane further comprises a load swing acquisition unit for acquiring a swing amount and a swing speed of the load. The speed command generating unit generates the speed command using the weight swing amount and the weight swing speed.

17. The crane control method according to claim 16, characterized in that: The load swing acquisition unit estimates the load swing amount and the load swing speed based on an angular frequency of the load swing or the angular frequency obtained from the length of the wire rope and the speed command of the crane.

18. The crane control method according to claim 10 or 11, characterized in that: The crane also has an obstacle detection unit and a collision judgment unit. The obstacle detection unit detects obstacles to the hanging load and the crane, The collision judgment unit judges whether there is a risk of collision between the obstacle detected by the obstacle detection unit and at least one of the hanging load and the crane, and outputs a stop operation start signal to the speed instruction generation unit to start a stop operation if there is a risk of collision.

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