CN114650962A

CN114650962A - Crane and crane control method

Info

Publication number: CN114650962A
Application number: CN202080078306.2A
Authority: CN
Inventors: 桃井康行; 家重孝二; 及川裕吾
Original assignee: Hitachi Industrial Equipment Systems Co Ltd
Current assignee: Hitachi Industrial Equipment Systems Co Ltd
Priority date: 2019-11-12
Filing date: 2020-07-02
Publication date: 2022-06-21
Also published as: EP4059875A1; WO2021095296A1; EP4059875A4; JP7297645B2; JP2021075372A

Abstract

The invention provides a crane which can reduce the braking distance and has high safety while inhibiting the swing of a hoisting weight generated when the crane stops. The crane control device is provided with a speed command generation part for generating a moving speed command of the horizontal moving device and a crane control part for moving the horizontal moving device according to the speed command. The speed command generation unit generates a deceleration pattern (v1) in which deceleration is performed from the time when a stop operation start signal is input, and an acceleration/deceleration pattern (v2) in which acceleration/deceleration is performed so as to cancel a hanging weight swing (x01) generated by superimposing a hanging weight swing (x0) at the time of starting a stop operation and a hanging weight swing (x1) generated when the horizontal movement device is driven by the deceleration pattern (v 1). The horizontal movement device is driven in accordance with a deceleration pattern (v1) from the start of the stopping operation, and is driven in accordance with an acceleration/deceleration pattern (v2) such that the timing at which the swinging amount of the hoist swing (x01) is maximized coincides with the center timing of the acceleration/deceleration pattern (v 2).

Description

Crane and crane control method

Technical Field

The present invention relates to a technique for controlling the operation of a crane that suspends and transports a suspended weight. And more particularly to a crane, a crane control apparatus, a crane control method, and a program for controlling a crane.

Background

In recent years, as skilled operators of cranes have become older and the number of cranes installed has increased, there has been an increasing number of people driving (operating) cranes by unskilled operators. In the crane operation by an unskilled operator, there is a risk that the crane operation is unfamiliar due to an erroneous judgment of the position and height of an obstacle, an unnoticed prediction of the crane operation such as a peripheral obstacle or a swinging of a hoisting weight, and an operation error occurs due to an unaccustomed operation of the crane. Therefore, in the crane operation by the unskilled operator, the occurrence of accidents such as collision and seizure of the hoist against the obstacle is more likely than in the crane operation by the skilled operator.

As one of measures for preventing an accident, there is a technique disclosed in patent document 1. Patent document 1 discloses, as a control method for stopping a crane while suppressing a swing of a suspended load, a method in which, at the start of an operation for stopping the crane, a shift operation or a mechanical brake is performed first, and then a reverse shift operation or a mechanical brake is performed 1 or more times at a timing after 1/2 in a swing cycle thereof, or a reverse shift operation or a mechanical brake is performed 1 or more times at a timing after 1/4 in a swing cycle thereof.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 8-324960

Disclosure of Invention

Problems to be solved by the invention

In the method disclosed in patent document 1, the hoisting swing is suppressed by operating the shift position (triangular wave velocity pattern) 1 or more times after the deceleration by the shift position operation or the mechanical brake, but the operation is not reliably stopped by 1 operation, and as a result, the reduction of the braking distance cannot be expected. In contrast, it is required to stop the crane quickly and safely, that is, to suppress the swing of the hoist in the case where a momentary change such as a stop occurs, and to have a short braking distance.

Here, when the crane speed is changed, the time to reach the target speed or the time or the moving distance of the speed change within a certain range is inversely related to the magnitude of the hoisting swing. That is, when the change rate of the crane speed is increased, the time or the travel distance becomes short, but the hoisting swing becomes large. In particular, when the speed is changed sharply, the problem becomes more remarkable. For example, when the crane is stopped, the braking distance for the trolley to move until the trolley stops is short, but a large hoisting swing occurs. In order to reduce the hoisting swing, the speed change time (for example, deceleration time) may be extended or control for suppressing the hoisting swing may be applied.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique for controlling the operation of a crane with higher safety, which can reduce the braking distance and time while suppressing the swing of a hoist.

Means for solving the problems

In order to solve the above problem, the present invention generates a second speed pattern that cancels a "superimposed hoisting swing" (control means control in which a target speed or a speed change is within a certain range) generated by superimposing a hoisting swing at the start of crane control and a hoisting swing generated by a first speed pattern of crane control, and controls the operation of the crane using the acceleration/deceleration pattern. As an example of the above, a crane includes a horizontal movement device that horizontally moves a hoist suspended by a wire rope in a horizontal direction, a speed command generation unit that generates a speed command for controlling the horizontal movement device, and a crane control unit that controls a speed of the horizontal movement device in accordance with the speed command, wherein the speed command generation unit generates a first speed mode in which a speed at the start of a speed change of the horizontal movement is changed to a predetermined speed and a second speed mode in which acceleration and deceleration are performed so as to cancel a third hoist swing generated by superimposing a first hoist swing at the start of the speed change and a second hoist swing generated by driving in the first speed mode as the speed command, and controls the horizontal movement device in accordance with the generated first speed mode and the generated second speed mode And (4) placing.

The present invention also includes a control method for a crane, a program for executing the control method, and a program for controlling a crane.

Here, the term "wire rope" is defined to mean not only a wire rope but also various types of tools that can be used to suspend a heavy object, such as a chain, a wire, a rope, a belt, and a cable.

Effects of the invention

According to the present invention, since the swing of the suspended load due to the speed change can be offset or reduced by a smaller number of acceleration and deceleration, the distance to the target speed can be reduced while suppressing the swing of the suspended load, and the safety of the crane can be improved.

Drawings

Fig. 1 is a diagram showing a mechanism in an example of a crane which is an object of the present invention.

Fig. 2 is a diagram showing a structure of a crane according to embodiment 1 of the present invention.

Fig. 3 is a diagram showing a velocity pattern generated in embodiment 1.

Fig. 4 is a diagram showing a process flow of a speed command generating unit of a crane according to embodiment 1.

Fig. 5 is a diagram illustrating an operation example of embodiment 1.

Fig. 6 is a diagram showing a structure of a crane according to embodiment 2 of the present invention.

Fig. 7 is a diagram showing a structure of a crane according to embodiment 3 of the present invention.

Detailed Description

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

Here, the present invention is effective for various cranes capable of moving a hoist weight in a horizontal direction. That is, the present invention is applicable not only to a crane (e.g., overhead crane) that hoists a load by a trolley in a transverse direction and a longitudinal direction, but also to a crane (e.g., ship unloader) that performs only a transverse direction or a longitudinal direction, or a so-called mobile crane. That is, in the present specification, the term "crane" includes all kinds of cranes capable of moving a hoisting weight in a horizontal direction. In addition, horizontal also includes curvilinear movements performed by the boom of a mobile crane or the like. That is, the movement includes a movement in which the swing of the hoist with respect to the hoist may occur due to the movement.

In addition, a heavy object (hoist) to be transported by a crane is suspended and transported by a wire rope, a chain, or the like, and any tool that can be used for suspending a heavy object in the present invention is not limited to the material, shape, or the like. Therefore, as described above, the term "wire rope" in the present specification is described as a general term for a tool for suspending a heavy object.

That is, "steel cord" includes not only so-called steel cord but also chain, belt, wire, cable, wire, rope, and the like.

< example 1 >

A crane according to embodiment 1 of the present invention will be described with reference to fig. 1 to 5. In the drawings, the same reference numerals are assigned to the same devices (apparatuses), and description of existing devices may be omitted in the description of the following drawings.

Fig. 1 is a schematic diagram showing a mechanism of an overhead crane. As described above, the present invention is not limited to the bridge crane.

In fig. 1, a crane 1 is configured with rails 2 provided along walls on both sides of a building (not shown), a bridge 3 moving on the top surface of the rails 2, and a carriage 4 moving along the bottom surface of the bridge 3. A hoist (hoist), not shown, is provided below the carriage 4, and the hook 6 at the tip end of the wire rope 5 is raised and lowered by raising and lowering the wire rope 5. The hook 6 suspends the hoist 8 directly or via the cable 7, and the hoist 8 is raised and lowered as the hook 6 is raised and lowered. That is, the crane 1 can move the hoist 8 in the horizontal direction by the horizontal movement of the bridge 3 (hereinafter, simply referred to as "wale") and the horizontal movement of the trolley 4 (hereinafter, simply referred to as "wale"), and can raise and lower the hoist 8 in the vertical direction (up and down direction) by the hoisting machine.

In this embodiment, the carriage 4 is moved in the horizontal direction by using the lateral rows and the vertical rows (traveling) of the bridge 3. In fig. 1, the carriage 4 and the bridge 3 correspond to a horizontal movement device. Since the present invention relates to the operation of moving the hoist in the horizontal direction, the following description of embodiment 1 of the present invention will be made centering on the operation of moving in the horizontal direction by the horizontal rows and the vertical rows. Therefore, in the following description of the embodiment, the movement of the hoist means either or both of the movement (traverse) of the drive carriage 4 and the movement (vertical) of the drive bridge 3.

Fig. 2 is a diagram showing a structure of a crane according to embodiment 1 of the present invention. In fig. 2, the crane 1 is shown traversing the trolley 4 for simplicity of illustration, while the traversing by the bridge 3 is omitted in the figure. In addition, a driving unit such as a motor for moving the carriage 4 and the bridge 3 is omitted.

In fig. 2, reference numeral 10 denotes a speed command generating unit that generates a speed pattern or the like for controlling the horizontal movement device (the bridge 3 and the carriage 4) to move the hoist 8 to the target position, and an example using a general-purpose computer is shown here. Reference numeral 101 denotes an MPU (micro processing unit) which executes arithmetic processing such as a generation speed pattern using a built-in program, data, and the like. 102 is a memory storing its program, data, and the like. Reference numeral 103 denotes an input/output control unit for inputting data and signals from the outside and outputting the signals obtained by performing arithmetic processing on the MPU to the outside. Reference numeral 104 denotes a bus for transmitting signals and data between the respective constituent devices in the speed command generating unit 10. Reference numeral 12 denotes a crane control unit, which receives the speed pattern output from the speed command generation unit 10 and controls the horizontal movement (lateral movement) speed of the cart 4. The crane control unit 12 outputs a control signal corresponding to the input speed pattern to the cart 4. The crane control unit 12 may have the function of the speed command generation unit 10, and the speed command generation unit 10 may output a control signal.

Although not shown in fig. 2, the speed command generating unit 10 outputs a speed pattern for controlling the horizontal movement (wale) speed of the bridge 3, not only when the vehicle 4 is controlled in the wale direction. On the bridge 3 side, the horizontal movement (wale) speed of the hoist is controlled according to the speed pattern. The speed command generation unit 10 receives the wire rope length L0, which is an output of a wire rope length detector not shown, and receives the speed Vs at the time of starting the stop operation from a speed detector also not shown. When the wire length L0 and the speed Vs do not change, these data may be stored in the memory 102. In addition, 9 denotes an obstacle. The obstacle 9 is not always present in the middle of the conveyance path of the hoist, but a case where there is a possibility is assumed.

In the present description, the deceleration and stop of the crane are described as examples, but the present invention can be applied to control to a target speed such as acceleration or deceleration to a speed not reaching the stop in each example. In this case, the speed at the deceleration start time is the speed at the start of control. The deceleration start time may be a predicted value based on control, in addition to the input from the speed detector.

Next, the details of the control content of the crane in fig. 2 will be described. In fig. 2, when the operator instructs the movement direction of the hoist with the operation input device 100, the speed command generating unit 10 generates a speed command for moving the bridge 3 and the carriage 4 in a direction corresponding to the instructed movement direction. The crane control unit drives the gantry 3 and the carriage 4 in accordance with the generated speed command to move the hoist 8 in the horizontal direction (in this case, traverse).

When the operator intends to stop the movement in the horizontal direction (horizontal row or vertical row), the operator instructs the stop operation start signal 11 to the speed command generating unit 10 using the operation input device 100. For example, a button corresponding to the movement direction is disposed in the operation input device 100. When a button corresponding to the desired direction is pressed at the time of starting the movement and the button is released for operation at the time of stopping the movement, a stop operation start signal 11 as a trigger for starting the stop operation is input to the speed command generating unit 10 when the button is released. Alternatively, the stop operation start signal 11 may be input from a stop button or an external device provided separately.

Fig. 3 is a diagram of the speed pattern generated by the speed command generating unit 10 when the stop operation start signal 11 is input. When the stop operation start signal 11 is input, the carriage and the vehicle are first driven in the first speed pattern v1 in which the speed of the carriage and the vehicle is reduced by the time period T1 from Vs at the start of the stop operation.

Then, in order to cancel the hoist sway at the start of the stop operation and the hoist sway generated by the drive at v1, the vehicle is driven in the second speed pattern v2 in which acceleration and deceleration are performed for the time period T2 and the maximum speed Vdmax after Tw from the start of the stop operation. These speed patterns are obtained from the relational expressions described below. The speed pattern may be any pattern that indicates a change in speed.

First, a transfer function p(s) from a speed command of the crane to a swing amount of the hoist weight is given by the following equation.

P(s) ═ -s/(s ^2+ wr ^2) … … (math figure 1)

Here, wr is the angular frequency of the swing of the hoist, and is obtained from the swing cycle Tc of the hoist at wr of 2 × pi/Tc. Alternatively, the distance L from the rotation center of the wire rope to the center of gravity of the suspended weight is obtained for wr ═ sqrt (g/L) (g: gravitational acceleration). L is obtained by adding a distance Δ L from the hook position to the center of gravity of the suspended weight suspended by the wire to the length L0 of the wire rope. The Δ L varies depending on the hoisting weight and the wire used, but may be measured by a distance sensor or the like attached to the cart or input by the operator and stored in the memory 102 in advance.

The hoist swing x0(t) at the start of the stop operation is given by the following equation.

x0(t) ═ a0 × sin (wr × t + θ 0) … … (equation 2)

Here, when the weight swing amount at the start of the stop operation is x0(0) and the weight swing speed is v0(0), a0 and θ 0 are as follows.

A0 ═ sqrt (x0(0) ^2+ (v0(0)/wr) ^2) … … (equation 3)

θ 0 ═ atan ((v0(0)/wr)/x0(0)) … … (equation 4)

When the first velocity pattern V1 is given by a function V1(t) with respect to time t, the weight swing X1(t) generated when the vehicle is driven by V1(t) can be obtained by laplace transform V1(t) to obtain V1(s) and inverse laplace transform X1(s) ═ p(s) × V1(s), and is given as shown in the following equation.

x1(t) ═ a1 × sin (wr × t + θ 1) … … (equation 5)

Here, when v1(t) is decelerated at a constant deceleration, a1 and θ 1 are as follows.

A1 is 2 Vs sin (T1 wr/2)/(T1 wr 2) … … (equation 6)

θ 1 ═ T1 × wr/2 … … (equation 7)

Here, Vs is the speed of the vehicle at the start of the stop operation, and T1 is the deceleration time.

When the second speed pattern V2 is given by a function V2(t) with respect to time t, the sling swing X2(t) generated when the vehicle is driven by V2(t) can be obtained by laplace transform V2(t) to obtain V2(s), and inverse laplace transform X2(s) ═ p(s) × V2(s), and is given as shown in the following equation.

x2(t) ═ a2 × sin (wr × t + θ 2) … … (equation 8)

When v2(t) is a trapezoidal wave, a2 and θ 2 are as follows.

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

… … (mathematics 9)

θ 2 ═ pi/2-Tw × wr-T2 × wr/2 … … (equation 10)

Here, r is the upper/lower bottom of the trapezoidal wave.

In order to suppress the suspended weight swing after the stop, the suspended weight swing x01(t) obtained by superimposing x0(t) and x1(t) may be offset by x2 (t).

x01(t) is given by the following equation.

x01(t) ═ a01 × sin (wr × t + θ 01) … … (equation 11)

Here, a01 and θ 01 used in equation 11 are as follows.

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)

… … (math figure 12)

Theta 01 ((-Vs + cos (T1 × wr) + A0 × T1 × wr ^2 × sin (theta 0))/(A0 × T1 × wr ^2 cos (theta 0) + Vs + sin (T1 × wr))) … … (math 13)

In order to cancel x01(t) with x2(t), the phases of x01(t) and x2(t) may be matched to cancel each other in amplitude. Accordingly, θ 01 may be equal to θ 2, and a01 may be equal to-a 2.

From θ 01 ═ θ 2, the following formula can be obtained.

Tw + T2/2 ═ (π/2- θ 01)/wr … … (equation 14)

Therefore, x01(T) at the center time (T ═ Tw + T2/2) of v2(T) is as follows.

x01(Tw + T2/2) ═ A01 × sin (π/2) … … (equation 15)

This indicates that the time at which x01(t) is maximized may coincide with the center time of v2 (t).

From a01 ═ a2, the following formula can be obtained.

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

… … (mathematics 16)

From this equation, T2, Vdmax, and r can be obtained as follows.

First, when the set speed V of the set time T, Vdmax of T2 is given, r is determined as follows. If T2 × wr/2 is assumed to be minute, Vdmax can be approximated as shown in the following equation.

Vdmax 2 × A01/(1+ r)/T2 … … (equation 17)

Thus, r is determined as shown in the following equation.

r 2 × a01/T/(k × V) … … (equation 18)

Here, k is a correction coefficient in consideration of the influence of the approximation. The exact solution for Vdmax is calculated from the determined r using equation 16.

When the set speed V of Vdmax and the set acceleration α of the acceleration of the trapezoidal wave are given, T2 and r may be determined as follows. If T2 × wr/2 is small, the acceleration can be obtained as shown in the following equation.

α＝Vdmax/((1-r)*T2/2)

4 x A01/(1-r 2)/T2 2 … … (equation 19)

Thus, T2 and r are determined as shown in the following equation.

T2 ═ a01/(k × V) + (k × V)/α … … (equation 20)

r 2 α a01/(α a01+ (k V) ^2) -1 … … (equation 21)

From the determined T2, r, a rigorous solution for Vdmax is calculated using equation 16.

Further, when r is 0, that is, a triangular wave is used, and a set speed V of Vdmax is given, T2 is determined as follows. When r is 0, Vdmax is represented by the following formula.

Vdmax 1/8A 01T 2 wr 2/sin (T2 wr/4) ^2 … … (equation 22)

If T2 × wr/4 is small, Vdmax can be approximated as shown in the following equation.

Vdmax 2 × A01/T2 … … (math 23)

Thus, T2 is determined as shown in the following equation.

T2 ═ 2 × a01/(k × V) … … (equation 24)

Here, k is a correction coefficient in consideration of the influence of the approximation. A rigorous solution to Vdmax is calculated using equation 22 based on the determined T2.

When r is 0 and the set acceleration α of the acceleration of the trapezoidal wave is given, T2 and Vdmax may be determined as follows. The acceleration can be obtained as shown in the following equation.

α＝Vdmax/(T2/2)

1/4A 01 wr ^2/sin (T2 wr/4) ^2 … … (math figure 25)

Thus, T2 is determined as shown in the following equation.

T2 ═ 4/wr ^ asin (1/2 ^ sqrt (A01 ^ wr ^ 2/alpha)) … … (equation 26)

Vdmax is calculated by equation 22 according to the determined T2.

The start time Tw of v2(t) can be obtained by the following equation.

Tw ═ (pi/2-theta 01)/wr-T2/2 … … (equation 27)

When Tw <0 in this equation, it is necessary to start driving by v2(t) before the start of the stop operation, and therefore, this cannot be achieved. In this case, x01(t) is a periodic function of the angular period 2 π, so the time when the weight swinging amount is maximum after 1 cycle can be made to coincide with the center time of v2 (t). Thus, Tw is determined by the following equation.

Tw ═ ((2 × n +1/2) × pi- θ 01)/wr-T2/2 … … (equation 28)

Here, n is 0 or 1.

As described above, the start time Tw and the time period T2 of the second speed pattern v2, the maximum speed Vdmax, and the upper bottom r/lower bottom r of the trapezoidal wave can be determined.

When the speed Vs at the start of the stop operation is extremely low, T1 is substantially 0. In this case, since the hoist swing x01(t) obtained by superimposing the hoist swing x0(t) at the start of the stop operation and the hoist swing x1(t) in the first speed mode is only x0(t), the amplitude a01 and the phase θ 01 of x01(t) may be regarded as the amplitude a0 and the phase θ 0 of x0 (t).

In order to shorten the braking distance, it is preferable to reduce the period T1 of the first speed pattern v1(T) and the period T2 of the second speed pattern v2 (T). Therefore, it is preferable to make the deceleration V1(t), the set value V of the maximum speed V2(t), and the set value α of the acceleration as large as possible according to the performance of the bridge and the carriage.

Fig. 4 is a flowchart of the processing of the speed command generating unit 10. Details of the processing are described below.

In S01, the amplitude a0 and the phase θ 0 of the hoist swing amount x0(t) at the start of the stop operation are estimated from the hoist swing amount x0(0) and the hoist swing speed v0(0) at the start of the stop operation by using equations 3 and 4. Further, if the bridge and the car speed Vs at the start of the stopping operation are extremely low and a0 is smaller than the allowable value of the hoist swinging amount, the calculation thereafter may not be performed, and the operation may be stopped.

In S02, based on a0, θ 0, and Vs, the time length T1 of the first velocity pattern v1, and the angular frequency wr of the hoist oscillation, the amplitudes a01 and θ 01 of the hoist oscillation x01 obtained by superimposing x0 on the hoist oscillation x1 generated by the v1 driving are obtained by using

equations

12 and 13. At this time, when Vs is at an extremely low speed, the driving by v1 is not performed (T1 is 0), and a01 is made equal to a0 and θ 01 is made equal to θ 0.

In S03, from a01 and wr, and a set value V of the maximum speed of the second speed pattern V2 in which the upper bottom/lower bottom r of the trapezoidal wave is 0, that is, a triangular wave, the time length T2 and the maximum speed Vdmax of V2 are obtained by using equations 24 and 22.

In S04, T2 obtained in S03 is compared with a threshold value T2S ═ 2 × ((pi/2- θ 01)/wr-T1). If T2> T2s, there is a possibility that T2 can be shortened by making r >0, so parameter calculation that defines the maximum speed and the time period is performed.

In S05, Vdmax is V, T2, T2S, and Vdmax and r are obtained by expression 17 and expression 18. If the acceleration of the obtained trapezoidal wave is equal to or less than the maximum acceleration, the trapezoidal wave that can be driven is determined and the process proceeds to S10.

At S06, it is determined whether or not the acceleration exceeds the maximum acceleration α max, and if so, a parameter calculation is performed to define the acceleration so that the acceleration is equal to or less than α max.

In S07, T2 and Vdmax are calculated by using expressions 26 and 22, assuming that the set value of the acceleration is α max.

In S08, it is determined whether or not the acceleration of the triangular wave is equal to or less than an allowable value (minimum allowable acceleration α min). When the allowable value is less than or equal to the allowable value, T2 may be shortened by setting r >0, and therefore, parameter calculation for specifying the maximum speed and acceleration is performed.

In S09, with Vdmax being V and acceleration being α min, T2, r, and Vdmax are obtained by expression 20, expression 21, and expression 16.

In S10, start time Tw is calculated using equation 28. First, the calculation is performed with n equal to 0, and the calculation is performed again with n equal to 1 when Tw is less than 0.

When the parameters of the speed pattern are calculated as described above, since the time length is shortened by using the trapezoidal wave when the time length is large when the triangular wave is used, the time until the hoist swings can be shortened and the braking distance can be shortened while suppressing the swing of the hoist.

Fig. 5 is a diagram for explaining the operation of the present example 1, and shows the time course of the carriage speed and the swing amount of the hoist from above. As can be seen from fig. 5, from the start of the stop operation when the stop operation start signal 11 is input, deceleration is started in the first speed pattern. Then, the hoist is driven by the trapezoidal wave speed command which is the second speed mode, thereby canceling the hoist sway generated at the start of the stop operation and due to deceleration by the trapezoidal wave speed command, and successfully suppressing the hoist sway after the carriage stops. Further, since the stop can be performed with the trapezoidal wave of 1 st order, the braking distance can be shortened as compared with a method of performing a plurality of operations.

As described above, according to embodiment 1, the swing of the suspended load due to deceleration can be offset by 1 acceleration/deceleration, and the braking distance can be reduced while suppressing the swing of the suspended load, thereby improving the safety of the crane.

In addition, although the above embodiment has been described with respect to the case where the crane is stopped, the suspended weight swing can be similarly suppressed even when the speed is changed to an arbitrary speed. The first speed pattern and the second speed pattern may overlap, that is, Tw < T1.

< example 2>

Next, a crane according to embodiment 2 of the present invention will be described. Here, a repetitive description about points common to the above-described embodiments is omitted. Fig. 6 is a diagram showing the structure of a crane according to embodiment 2. The embodiment 2 is largely different from the embodiment 1 shown in fig. 2 in that a device for acquiring a swing amount and a swing speed of a hoist weight is provided in fig. 6. In the speed command generation of the above embodiment, the amplitude a0 and the phase θ 0 of the hoist swing x0 at the start of the stop operation are used, and they can be obtained from the hoist swing amount x0(0) at the start of the stop acquired by the hoist swing amount acquisition means, the hoist swing speed v0(0), and the equations 3 and 4.

The hoist swinging amount acquiring device is a device for obtaining the swinging amount and the swinging speed of the hoist. The device for acquiring the swing amount of the hoist in the present embodiment includes a swing amount detector 13 for measuring the swing amount of the hoist, and a swing speed calculation device for calculating the swing speed of the hoist based on the measured swing amount of the hoist. The hoist swinging amount detector 13 can be realized by observing (measuring) the swinging of the hook 6 or the hoist 8 with a camera or a three-dimensional laser distance sensor mounted downward on the carriage, for example. The hoisting swing speed calculation device performs, for example, a differential calculation or a pseudo-differential calculation on the measured hoisting swing amount. In the present embodiment, the hoist swing speed calculation device is not separately provided, but is configured as one function of the speed command generation unit 10.

The hoisting weight swing amount acquisition device may be provided with a hoisting weight swing amount estimation device for estimating the hoisting weight swing amount and the hoisting weight swing speed, and the hoisting weight swing amount and the hoisting weight swing speed may be obtained by estimation based on the angular frequency wr of the hoisting weight swing and the speed commands of the bridge frame and the car. Therefore, the hanging weight swing amount obtaining device can also directly detect the hanging weight swing amount without using the hanging weight swing amount detector 13. The angular frequency wr can be estimated from the rope length L0. The function of the hoist oscillation amount estimation device may be configured to be calculated in the speed command generation unit 10.

When the speed command for the bridge frame and the car is vt (t) and the sling swinging amount is x (t), the estimated sling swinging amount and the estimated sling swinging speed can be calculated by the following equations.

X(s) ═ p(s) · vt(s) … … (equation 29)

Therefore, the sling oscillation amount estimation device can estimate the sling oscillation amount by performing a predetermined filter operation for p(s) on the transfer function vt (t), and can estimate the sling oscillation speed by differentiating the obtained sling oscillation amount.

As described above, according to embodiment 2, the swing of the hoist due to deceleration can be canceled out by 1 acceleration/deceleration, the braking distance can be reduced while suppressing the swing of the hoist, and the safety of the crane can be improved.

< example 3 >

Next, a crane according to embodiment 3 of the present invention will be described. Here, a repetitive description about the common contents with the above-described embodiments is omitted.

Fig. 7 is a diagram showing the structure of a crane according to embodiment 3 of the present invention. In this embodiment, the obstacle detector 14 detects the hoist 8, the carriage 4, and the obstacle 9 around the bridge 3. The collision determination device 15 is provided with a detection signal input from the obstacle detector 14, determines whether there is a risk of collision between the obstacle 9 and any one of the hoist 8, the vehicle 4, and the bridge 3, and outputs the stop operation start signal 11 to the speed command generation unit 10 when it is determined that there is a risk of collision.

The obstacle detector 14 can detect an obstacle around the hoist weight by observing the periphery of the hoist weight 8 with a camera or a three-dimensional laser distance sensor installed downward on the cart 4, for example. The collision determination device 15 outputs the stop operation start signal 11 promptly when a collision between the detected obstacle and the hoist weight is predicted. When the stop operation start signal 11 is input, the speed command generating unit 10 generates the same speed pattern as in the above embodiment. That is, a first speed pattern for decelerating from a speed at the start of deceleration to a first deceleration end speed and a second speed pattern for performing acceleration and deceleration for canceling a hanging weight swing generated when the horizontal movement device is driven in accordance with the first speed pattern are generated. The generated speed pattern is output to the crane control unit 12, and the crane control unit 12 controls the speeds of the bridge 3 and the trolley 4 to stop the crane. With this control operation, collision of the hoist with the obstacle and an accident of jamming can be prevented.

Further, for example, by measuring the distance to a wall, a stopper, or another crane traveling on the same track using a length measuring sensor attached to the carriage 4 or the bridge 3, it is possible to predict the collision of the crane with the wall, the stopper, or the other crane. When such a situation is predicted, if a stop operation start signal is promptly output to stop the crane, it is possible to prevent a collision or a seizure accident between the crane and a wall, a stopper, or another crane.

According to the crane according to embodiment 3 of the present invention described above, since the swing of the hoist due to deceleration can be canceled out by 1-time acceleration/deceleration, the braking distance can be reduced while suppressing the swing of the hoist, and the safety of the crane can be improved. Further, collision and seizure accidents can be prevented, and the safety of the crane can be further improved.

Further, according to each of the embodiments using the stop control as an example, since the swing of the hoist due to deceleration can be offset or reduced by 1-time acceleration/deceleration, the braking distance can be reduced while suppressing the swing of the hoist, and the safety of the crane can be improved.

The present invention is not limited to the above embodiments, and various modifications are possible. For example, the above-described embodiments are described in detail to explain the present invention easily and understandably, and are not limited to having all the structures described. In addition, a part of the structure of one embodiment may be replaced with the structure of another embodiment, and the structure of another embodiment may be added to the structure of one embodiment. Other configurations can be added, deleted, and replaced to the configurations of the embodiments. In particular, the crane control is not limited to stopping, and can be applied to deceleration or acceleration to an arbitrary speed (target speed). This includes keeping the target speed fixed within a prescribed range. In addition, the braking distance is a moving distance up to the target speed.

Description of the reference numerals

1 … … crane, 2 … … track, 3 … … bridge, 4 … … trolley, 5 … … wire rope, 6 … … hook, 7 … … cable, 8 … … hanging weight, 9 … … obstacle, 10 … … speed command generating part, 11 … … stop operation start signal, 12 … … crane control part, 13 … … hanging weight swinging amount detector, 14 … … obstacle detector, 15 … … collision judging device.

Claims

1. A crane comprising a horizontal movement device for horizontally moving a hoist suspended by a wire rope in a horizontal direction, a speed command generation unit for generating a speed command for controlling the horizontal movement device, and a crane control unit for controlling the speed of the horizontal movement device in accordance with the speed command, the crane characterized in that:

the speed command generation unit generates, as the speed command, a first speed mode in which a speed at a time of starting a speed change of the horizontal movement is changed to a predetermined speed, and a second speed mode in which acceleration and deceleration are performed so as to cancel a third hoist swing generated by superimposing a first hoist swing at the time of starting the speed change and a second hoist swing generated by driving in the first speed mode,

the crane control unit controls the horizontal movement device according to the generated first speed pattern and the second speed pattern.

2. A crane as claimed in claim 1, wherein:

the speed command generating unit uses a deceleration mode in which the horizontal movement of the crane is decelerated and stopped as the first speed mode.

3. A crane as claimed in claim 1 or 2, wherein:

the crane control unit controls the horizontal transfer device in the first speed mode from the start of the speed change, and controls the horizontal transfer device so that a timing at which the swing amount of the third hoisting weight is maximized coincides with a center timing of the second speed mode.

4. A crane as claimed in any one of claims 1 to 3, wherein:

the speed command generation unit calculates a start time, a duration, and a maximum speed of control in the second speed mode based on an amplitude and a phase of the third hoist swing, an angular frequency corresponding to the length of the wire rope, the speed of the crane at the start of the speed change, and the time of the speed change in the first speed mode, and generates the first speed mode.

5. The crane as claimed in claim 4, wherein:

the speed command generation unit calculates the amplitude and phase of the first hoist swing based on the swing amount, swing speed, and angular frequency in the first hoist swing, and calculates the amplitude and phase of the third hoist swing based on the calculated amplitude, phase, and angular frequency of the first hoist swing and the deceleration time in the deceleration mode, which is the first speed mode.

6. A crane as claimed in claim 4 or 5, wherein:

the speed command generation section generates a second speed pattern appearing as a trapezoidal wave as the second speed pattern.

7. The crane as claimed in claim 6, wherein:

the speed instruction generating section generates a first speed pattern in which a speed change of the horizontal movement appears to be accelerated or decelerated at a certain ratio as the first speed pattern,

when the start time Tw of the trapezoidal wave is set to T2, the maximum speed Vdmax is set to r, the angular frequency wr is set to r, the amplitude of the third lifting swing is a01, and the phase θ 01 is set to (n is 0 or 1), the following conditions are satisfied:

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)。

8. a crane as claimed in any one of claims 1 to 7, wherein:

further comprises a hoist swing acquiring unit for acquiring a swing amount and a swing speed of the hoist,

the speed command generation unit generates the speed command using the sling oscillation amount and the sling oscillation speed.

9. The crane as claimed in claim 8, wherein:

the hoist swinging amount and the hoist swinging speed are estimated by the hoist swinging amount acquisition unit based on the angular frequency of the hoist swinging or the angular frequency obtained from the length of the wire rope, and the speed command of the crane.

10. The crane according to any of claims 1-9, further comprising:

an obstacle detecting unit that detects an obstacle to the hoist weight and the crane; and

and a collision determination unit that determines whether or not there is a risk of collision between the obstacle detected by the obstacle detection unit and at least one of the hoist and the crane, and outputs a stop operation start signal to start a stop operation to the speed command generation unit when there is the risk of collision.

11. A crane control method for controlling a crane, the crane including a horizontal movement device for horizontally moving a hoist suspended by a wire rope in a horizontal direction, a speed command generation unit for generating a speed command for controlling the horizontal movement device, and a crane control unit for controlling a speed of the horizontal movement device in accordance with the speed command, the crane control method comprising:

generating, as the speed command, a first speed pattern in which a speed at the start of changing the speed of the horizontal movement is changed from a predetermined speed and a second speed pattern in which acceleration and deceleration are performed so as to cancel a third hoist swing generated by superimposing a first hoist swing at the start of changing the speed and a second hoist swing generated by driving in the first speed pattern, by the speed command generating unit,

controlling the horizontal transfer device by the crane control unit in accordance with the generated first speed pattern and the second speed pattern.

12. The crane control method according to claim 11, wherein:

13. The crane control method according to claim 11 or 12, wherein:

and controlling the horizontal transfer device in the first speed mode from the start of the speed change by the crane control unit, and controlling the horizontal transfer device so that a timing at which the swing amount of the third hoist swings is maximized coincides with a center timing of the second speed mode.

14. The crane control method according to any one of claims 11 to 13, wherein:

15. The crane control method as claimed in claim 14, wherein:

the speed command generation unit calculates the amplitude and phase of the first hoist swing based on the swing amount, swing speed, and angular frequency of the first hoist swing, and calculates the amplitude and phase of the third hoist swing based on the calculated amplitude, phase, and angular frequency of the first hoist swing and the deceleration time in the deceleration mode, which is the first speed mode.

16. The crane control method according to claim 14 or 15, wherein:

a second velocity pattern appearing as a trapezoidal wave is generated as the second velocity pattern by the velocity command generating section.

17. The crane control method as claimed in claim 16, wherein:

generating, as the first speed pattern, a first speed pattern in which a speed change of the horizontal movement appears to be accelerated or decelerated at a certain ratio by the speed instruction generating section,

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)。

18. the crane control method according to any one of claims 11 to 17, wherein:

the crane further includes a hoist swing acquiring unit that acquires a swing amount and a swing speed of the hoist,

the speed command generation unit generates the speed command using the hoist swinging amount and the hoist swinging speed.

19. The crane control method as claimed in claim 18, wherein:

20. The crane control method according to any one of claims 11 to 19, wherein:

the crane further has an obstacle detection section and a collision determination section,

detecting an obstacle to the hoist weight and the crane by the obstacle detecting unit,

the collision determination unit determines whether or not there is a risk of collision between the obstacle detected by the obstacle detection unit and at least one of the hoist weight and the crane, and outputs a stop operation start signal to start a stop operation to the speed command generation unit when there is the risk of collision.