WO2024181451A1 - Control device, crane, and control method - Google Patents

Abstract

The present invention minimizes long-period simple-harmonic oscillation generated in a conveyance object when the conveyance object is moved along an X-Y plane by a crane or the like.　The present invention comprises: a detection unit 41 which detects a change in target speed of a horizontal moving device H and updates the target speed; an acceleration waveform determination unit 42 which, from the speed difference between the updated target speed and the current speed of the horizontal moving device H, determines three acceleration waveforms, which are a first acceleration waveform P1, a second acceleration waveform P2, and a third acceleration waveform P3 for generating an acceleration waveform; a timing determination unit 43 which determines start timings for the three acceleration waveforms so that the respective phases of oscillatory waveforms generated in a hoisting load when the horizontal moving device H is driven according to each of the three acceleration waveforms are shifted by 1/3 from each other; an acceleration command signal generation unit 44 which generates an acceleration command signal indicating that the acceleration of the three acceleration waveforms is to start at the respective start timings determined by the timing determination unit 43; and a movement control unit 22 which generates a drive command signal on the basis of the acceleration command signal and drives the horizontal moving device H.

Description

CONTROL DEVICE, CRANE, AND CONTROL METHOD

The present invention relates to a control device and a control method for suppressing vibrations of a transported object suspended by a rope or the like, and to a control technology for suppressing long-period vibrations, such as pendulum vibrations, that occur in a transported object suspended by a crane or the like.

　It is known that the load suspended by a crane will oscillate in a pendulum motion, which is an obstacle to transportation, and various vibration control methods have been proposed to suppress the pendulum motion. In addition to methods for smoothing the operation, such as an S-curve to suppress the generation of vibration or a speed curve using a low-pass filter, methods that have been proposed for suppressing the vibration include a method of detecting or simulating the swing angle and applying vibration of the opposite phase, and a vibration control method using a notch filter.

For example, Patent Document 1 proposes a vibration control method that uses advanced control techniques such as equations of motion and Laplace transforms to perform vibration control.

JP 2022-096804 A JP 2021-075372 A

The vibration control method described in Patent Document 1 performs vibration control by making full use of advanced control such as equations of motion and Laplace transforms, which results in a complex control device and requires a lot of time for vibration control.

The present invention was made in consideration of these problems, and aims to reduce the shaking of the transported object more easily, and to automatically accelerate and decelerate at the optimal timing, thereby reducing the vibration of the transported object and suppressing the vibration of the transported object regardless of the skill of the operator.

A control device according to one aspect of the present invention is a control device that controls the speed of a drive device that moves a horizontal movement device from which a load is suspended in a horizontal direction based on an acceleration command signal, and is characterized by having a target speed update unit that detects a target speed change command to change the target speed of the drive device and updates the target speed, an acceleration waveform determination unit that determines three acceleration waveforms, a first acceleration waveform, a second acceleration waveform, and a third acceleration waveform, for generating an acceleration command signal from the speed difference between the target speed updated by the target speed update unit and the current speed of the drive device, a timing determination unit that determines the start timing of the three acceleration waveforms so that the phases of the vibration waveform of the load generated when the drive device is driven by each of the three acceleration waveforms are shifted by 1/3, an acceleration command signal generation unit that generates an acceleration command signal indicating that the acceleration of the three acceleration waveforms will start at the timing determined by the timing determination unit, and a drive control unit that generates a drive command signal based on the acceleration command signal to drive the drive device.

The acceleration command signal generation unit can generate an acceleration command signal by adding up the three acceleration waveforms for each time.

the timing determination unit determines the first time t1, which is the start timing of the first acceleration waveform, to be the time corresponding to the timing when the target speed update unit detects a command to change the target speed, the second time t2, which is the start timing of the second acceleration waveform, to be the time when 1/6 of the period of the vibration waveform of the suspended load generated when the drive device is driven by the first acceleration waveform has elapsed from the first time t1, and the third time t3, which is the start timing of the third acceleration waveform, to be the time when 1/6 of the period of the vibration waveform of the suspended load generated when the drive device is driven by the first acceleration waveform has elapsed from the second time t2;
The acceleration waveform determination unit includes:
The first to third acceleration waveforms are set as uniform acceleration waveforms with a predetermined acceleration A0, an acceleration time Ta is determined from a target speed, the first acceleration waveform is generated from a time function f1(t), the second acceleration waveform is generated from a time function f2(t), and the third acceleration waveform is generated from a time function f3(t),
If the target speed is faster than the current speed,
The time function f1(t) is
For t<t1, t>t1+Ta, f1(t)=0,
For t1≦t≦t1+Ta, f1(t)=A0 is a square wave.
The time function f2(t) is
For t<t2, t>t2+Ta, f2(t)=0.
For t2≦t≦t2+Ta, f2(t)=-A0, which is a square wave.
The time function f3(t) is
For t<t3 and t>t3+Ta, f3(t)=0.
For t3≦t≦t3+Ta, f3(t)=A0 is a square wave.
If the target speed is slower than the current speed,
The time function f1(t) is
For t<t1, t>t1+Ta, f1(t)=0,
For t1≦t≦t1+Ta, f1(t)=-A0 is a square wave.
The time function f2(t) is
For t<t2, t>t2+Ta, f2(t)=0.
For t2≦t≦t2+Ta, f2(t)=A0 is a square wave.
The time function f3(t) is
For t<t3 and t>t3+Ta, f3(t)=0.
For t3≦t≦t3+Ta, f3(t)=−A0 square wave.

The timing determination unit is
The first time t1, which is the start timing of the first acceleration waveform, is set to the time corresponding to the timing when the target speed update unit detects a command to change the target speed, the second time t2, which is the start timing of the second acceleration waveform, is set to the time when 1/3 of the period of the vibration waveform of the suspended load generated when the drive device is driven by the first acceleration waveform has elapsed from the first time t1, and the third time t3, which is the start timing of the third acceleration waveform, is set to the time when 1/3 of the period of the vibration waveform of the suspended load generated when the drive device is driven by the second acceleration waveform has elapsed from the second time t2.
The acceleration waveform determination unit includes:
The first to third acceleration waveforms are set to a constant acceleration waveform with a predetermined acceleration A0, and an acceleration time Ta is determined from a target speed;
A first acceleration waveform is generated from a time function f1(t), a second acceleration waveform is generated from a time function f2(t), and a third acceleration waveform is generated from a time function f3(t);
If the target speed is faster than the current speed,
The time function f1(t) is
For t<t1, t>t1+Ta/3, f1(t)=0,
When t1≦t≦t1+Ta/3, f1(t)=A0 is a square wave.
The time function f2(t) is
For t<t2, t>t2+Ta/3, f2(t)=0.
When t2≦t≦t2+Ta/3, f2(t)=A0 is a square wave.
The time function f3(t) is
For t<t3 and t>t3+Ta/3, f3(t)=0.
For t3≦t≦t3+Ta/3, f3(t)=A0 is a square wave.
If the target speed is slower than the current speed,
The time function f1(t) is
For t<t1, t>t1+Ta/3, f1(t)=0,
When t1≦t≦t1+Ta/3, f1(t)=-A0 is a square wave.
The time function f2(t) is
For t<t2, t>t2+Ta/3, f2(t)=0.
When t2≦t≦t2+Ta/3, f2(t)=−A0, which is a square wave.
The time function f3(t) is
For t<t3 and t>t3+Ta/3, f3(t)=0.
For t3≦t≦t3+Ta/3, f3(t)=−A0 square wave.

In addition, two target speeds, high and low, are provided, and the target speed update unit is able to not update the target speed if it detects a command to change the target speed of the drive unit before acceleration by the third acceleration waveform is completed.

The target speed update unit can stop not updating the target speed and update the target speed under certain conditions.

Two target speeds, a high speed and a low speed, are provided,
When a target speed change command for changing the target speed to zero is detected before the acceleration by the third acceleration waveform for changing the target speed from zero to a low speed is completed,
When a target speed change command for changing the target speed to zero is detected before the acceleration by the third acceleration waveform for changing the target speed from zero to a high speed is completed,
Or, when a target speed change command for setting the target speed to zero is detected before the acceleration by the third acceleration waveform for changing the target speed from a low speed to a high speed is completed,
the target speed update unit, when the time at which the target speed change command for setting the target speed to zero is detected is a time within the acceleration time Ta from the third time t3, stores a stop command time ts corresponding to the time at which the target speed change command for setting the target speed to zero is detected, and updates the target speed to zero;
The acceleration waveform determination unit includes:
determining a corrective acceleration time Tas for stopping from the current speed of the drive;
For t≦ts+Tas, fs(t)=−A0,
After generating a correction time function fs(t) for stopping, which is a square wave with fs(t)=0 when t>ts+Tas,
Replace the time function f(t) with the time function f(t),
Time function f2(t)=0
The time function f3(t) can be set to 0.

The drive device drives the motor using the power conversion device, and the drive control unit can provide the generated drive command signal to the power conversion device to drive the drive device.

The acceleration waveform can be a square waveform or a trapezoidal waveform.

In the present invention, the crane can have a control device.

A control method according to one aspect of the present invention is a control method for a control device that controls the speed of a drive device that moves a horizontal movement device from which a load is suspended in a horizontal direction based on an acceleration command signal, and is characterized by having a target speed update step of detecting a target speed change command that changes the target speed of the drive device and updating the target speed, an acceleration waveform determination step of determining three acceleration waveforms, a first acceleration waveform, a second acceleration waveform, and a third acceleration waveform, for generating an acceleration command signal from the speed difference between the target speed updated in the target speed update step and the current speed of the drive device, a timing determination step of determining the start timing of the three acceleration waveforms so that the phases of the vibration waveform of the load generated when the drive device is driven by each of the three acceleration waveforms determined in the acceleration waveform determination step are shifted by 1/3, an acceleration command signal generation step of generating an acceleration command signal indicating that the acceleration of the three acceleration waveforms will start at the timing determined in the timing determination step, and a drive control step of generating a drive command signal based on the acceleration command signal to drive the drive device.

The control method of another aspect of the present invention is a control method for controlling the speed of a controlled object, which generates three acceleration command signals that generate three vibrations that are shifted from each other by 1/3 of the period of the natural vibration generated in the controlled object due to the controlled speed, and reduces the natural vibration by executing speed control of the controlled object.

The natural vibration can be a pendulum vibration.

The acceleration command signal can be a constant acceleration command signal.

According to the present invention, the drive device is driven at a predetermined timing, making it possible to suppress vibrations in the transported object or the controlled object.

FIG. 1 is a diagram showing a schematic external configuration of a crane. FIG. 2 is a functional block diagram showing the configuration of the control device in the crane according to this embodiment. FIG. 3 is a diagram for explaining the principle of the speed change process. FIG. 4 is another diagram for explaining the principle of the speed change process. FIG. 5 is another diagram for explaining the principle of the speed change process. FIG. 6 is a flowchart showing the flow of the speed change process. FIG. 7 is a diagram for explaining the rope length L. FIG. 8 is a diagram showing an example of an acceleration waveform signal, a drive command signal, and a speed transition. FIG. 9 is a diagram showing other examples of acceleration waveform signals, drive command signals, and speed transitions. FIG. 10 is a diagram showing other examples of acceleration waveform signals, drive command signals, and speed transitions. FIG. 11 is a diagram showing other examples of acceleration waveform signals, drive command signals, and speed transitions. FIG. 12 is a diagram showing an example of speed transition in low-pass filter processing. FIG. 13 is a diagram showing other examples of acceleration waveform signals, drive command signals, and speed transitions. FIG. 14 is a flow chart showing the flow of the multi-speed speed change process. FIG. 15 is a diagram showing an example of an acceleration waveform signal, a drive command signal, and a speed transition in the case of multiple speeds.

[One embodiment]
A crane 1 according to an embodiment of the present invention will be described below with reference to the drawings. Note that the crane 1 will be described as an overhead crane that transports a suspended load in a horizontal direction. Each of the embodiments described below shows a preferred specific example of the present invention. The numerical values, components, the arrangement and connection order of the components, the processing order in the flow chart, and the like shown in the following embodiment are merely examples and are not intended to limit the present invention. Also, each figure is not necessarily a precise illustration.

<Equipment configuration>
1 is a diagram showing an example of the schematic external configuration of a crane 1. The crane 1 is configured to include traveling rails 2, 2 laid in a predetermined direction (e.g., east-west direction) in a horizontal plane of a building ceiling, a girder 4 arranged in a direction perpendicular to the traveling rails 2, 2 (e.g., north-south direction) and supported at both ends by traveling carriages 3, 3 moving on the traveling rails 2, 2, a trolley 5 moving on a lateral rail provided along the girder 4, and an electric hoist 7 arranged on the trolley 5. The traveling carriages 3, 3 are provided with traveling motors 3a, 3a, the trolley 5 is provided with a lateral motor 5a, and the electric hoist 7 is provided with a lifting motor 6.

In the crane 1, the electric hoist 7 is connected to an operating unit 8 by a cable 9 or the like. The operating unit 8 is equipped with push button switches for "east", "west", "south", "north", "up" and "down", for example. By operating the "east", "west", "south" and "north" push button switches (hereinafter referred to as horizontal push button switches when there is no need to distinguish between them individually), the electric hoist 7 moves (travels) in the east-west direction along the running rails 2, 2 by the running carriages 3, 3, and moves (transverses) in the north-south direction along the transverse rail of the girder 4 by the trolley 5. In addition, by operating the "up" and "down" push button switches (hereinafter referred to as up-down push button switches when there is no need to distinguish between them individually), a load (not shown) suspended from a load suspension hook 10 attached to a rope 11 is raised and lowered (hoisted up and down). Note that FIG. 1A is a diagram showing an example of the overall schematic configuration of the crane 1, and FIG. 1B is an enlarged view of the operating unit 8. The horizontal and up/down pushbutton switches will continue to operate if pressed and held down, and will stop operating if released and the switch is no longer pressed.

FIG. 2 is a block diagram showing the overall configuration of the control system for the crane 1 in this embodiment. The crane 1 has an operation control unit 21 and a movement control unit 22. The operation control unit 21 controls the crane 1, and generates control signals for the travel motor 3a, the traverse motor 5a, and the lifting motor 6 of the electric hoist 7 based on operation input from the operation unit 8. The operation control unit 21 is located in a control box (not shown) of the crane 1.

The operation control unit 21 has a control unit 31 and a memory unit 32. Although not shown in the figure, the control unit 31 is composed of a CPU (Central Processing Unit), a memory section (ROM (Read Only Memory), RAM (Random Access Memory), non-volatile memory, etc.), and other elements including hardware.

The control unit 31 executes a control program stored in the memory unit 32 to control the entire crane 1 and to execute a speed change process, which will be described later. When executing the speed change process, the control unit 31 functions as a detection unit 41, an acceleration waveform determination unit 42, a timing determination unit 43, an acceleration command signal generation unit 44, and a drive control unit 45. The operations of the detection unit 41 to the drive control unit 45 will be described later.

The memory unit 32 is composed of memory parts (ROM, RAM, non-volatile memory, etc.) and stores the above-mentioned control application programs and various data required for their execution.

The movement control unit 22 of the horizontal movement device is configured with a travel inverter 52 that outputs drive power for the travel motor 3a and a traverse inverter 53 that outputs drive power for the traverse motor 5a based on the control signal of the operation control unit 21, and the electric hoist 7 is configured with a lift inverter 54 that outputs drive power for the lift motor 6 and a lift control unit 51 that outputs a motor drive signal to the lift inverter 54. The motor is not limited to an electric motor, but may be a pneumatic motor, a hydraulic motor or any other type of prime mover, and may be any power device with a variable speed function that can be controlled by an acceleration command or a speed command. The travel inverter 52 and the traverse inverter 53 are devices that convert power from an AC or DC power source based on the control signal (speed command) of the operation control unit 21 and supply power to drive the travel motor 3a and traverse motor 5a, which are three-phase induction motors, and correspond to power conversion devices.

The traveling inverter 52 outputs driving power for the traveling motor 3a based on a driving command signal from the operation control unit 21. As a result, the traveling carts 3, 3 move, for example, in the east-west direction together with the girder 4, the trolley 5, and the electric hoist 7. The traverse inverter 53 outputs driving power for the traverse motor 5a based on a driving command signal from the operation control unit 21. As a result, the trolley 5 moves, for example, in the east-west direction together with the electric hoist 7. The lifting control unit 51 is mounted on the electric hoist 7 and outputs a driving command signal to the lifting inverter 54 based on a control signal from the operation unit 8 and/or the operation control unit 21, and the lifting inverter 54 outputs driving power for the lifting motor 6 to drive the electric hoist 7.

The electric hoist 7 suspends a load with a rope 11, and can raise and lower the load by winding up the rope 11 when driven by the lifting motor 6. The lifting motor 6 is equipped with an encoder 71 that can detect the rotation of the lifting motor 6 in order to detect the length of the rope 11.

<Principle of vibration suppression for suspended loads>
3 shows, for example, an acceleration waveform P1 consisting of an acceleration A0 in one direction of the traveling direction (in this example, the acceleration in the "east" direction) and an acceleration time Ta applied to the traveling cart 3, and a vibration waveform n1 of the suspended load generated when the traveling motor 3a of the traveling cart 3 is driven by the acceleration waveform P1. That is, when the speed of the traveling cart 3 is accelerated by the acceleration waveform P1, the suspended load suspended by the rope 11 from the electric hoist 7 moving horizontally together with the traveling cart 3 starts to swing, and after the timing (time t1+Ta) when the acceleration by the acceleration waveform P1 ends, a vibration of a vibration waveform n1 with a period Tf that can be represented (approximated) by a sine wave (hereinafter, referred to as a pendulum vibration as appropriate) continues. The period Tf is determined by the length from the rope support part of the electric hoist 7 to the center of gravity of the suspended load (hereinafter, referred to as a rope length L as appropriate). The acceleration waveform P1 is a rectangular waveform (constant acceleration waveform) that is generally used in the speed control of overhead cranes, and can be expressed by an acceleration A0 and an acceleration time Ta.

In addition to the acceleration waveform P1 and vibration waveform n1 shown in Figure 3, Figure 4 also shows vibration waveforms n2 and n3 that are 120 degrees out of phase with respect to the vibration waveform n1 (1/3 of the vibration period), and the acceleration waveforms P2 and P3 that generate the vibration waveforms n2 and n3. The sine waveform portion of the vibration waveform n2 is a waveform that is 120 degrees out of phase with respect to the sine waveform portion of the vibration waveform n1, and the sine waveform portion of the vibration waveform n3 is a waveform that is 120 degrees out of phase with respect to the sine waveform portion of the vibration waveform n1.

The second acceleration waveform P2 is an acceleration waveform consisting of a negative acceleration A0 (acceleration in the "west" direction in this example) and the same acceleration time Ta as the vibration waveform n1, with the acceleration start timing being time t2, which is 1/6 of the period Tf of the vibration waveform n1 from the acceleration start time t1 of the acceleration waveform P1. The third acceleration waveform P3 is an acceleration waveform consisting of a positive acceleration A0 (acceleration in the "east" direction in this example) and acceleration time Ta, with the acceleration start timing being time t3, which is 1/6 of the period Tf of the vibration waveform n1 from the acceleration start time t2 of the acceleration waveform P2. Although the acceleration waveforms P1, P2, and P3 have different acceleration directions, the magnitude and time of acceleration are the same (they have the same acceleration waveforms), so the amplitude of the vibration (pendulum vibration of the suspended load) induced by each of them is the same.

The sine waveform portions of the vibration waveforms n1 to n3 shown in Figure 4 have the same period and amplitude, but are shifted in phase by 120 degrees each, so the waveform W obtained by adding them together has an amplitude of zero when acceleration by the third acceleration waveform P3 ends (time t3 + Ta), as shown in Figure 5.

In addition, multiplying the positive acceleration A0 of acceleration waveform P1 shown in Figure 4 by the acceleration time Ta, multiplying the negative acceleration A0 of acceleration waveform P2 by the acceleration time Ta, and multiplying the positive acceleration A0 of acceleration waveform P3 by the acceleration time Ta, and adding them together, gives acceleration A0 x acceleration time Ta. In other words, if acceleration A0 is the acceleration output by the traveling cart 3 (traveling motor 3a) and acceleration time Ta is calculated by dividing the speed difference between the current speed of the traveling cart 3 and the target speed by acceleration A0 (i.e. the time it takes to reach the target speed at acceleration A0), acceleration A0 x acceleration time Ta becomes the target speed, so when the acceleration of acceleration waveform P3 ends, the traveling cart 3 reaches the target speed and enters a constant speed movement state in one direction.

Here, the traveling cart 3 has been used as an example, but when the trolley 5 moves "south" or "north," pendulum vibration occurs in the load suspended from the electric hoist 7, which moves horizontally together with the trolley 5. By similarly controlling the acceleration of the trolley 5, the target speed can be achieved while suppressing the vibration of the load. Hereinafter, when the traveling cart 3 and trolley 5, which are driven horizontally, are not distinguished from one another, they will be referred to as the horizontal movement device H.

In this embodiment,
determining start timings of the three acceleration waveforms so that the phases of the vibration waveforms of the suspended load generated when the horizontal moving device H is driven by each of the three acceleration waveforms are shifted by 1/3;
generating an acceleration command signal indicating that the acceleration of the three acceleration waveforms is to start at the determined start timing;
By driving the horizontal movement device H based on the acceleration command signal, the horizontal movement device H can achieve the target speed while suppressing vibration of the suspended load moving together with the horizontal movement device H.

If the target speed is faster than the current speed (target speed > current speed), as shown in Figure 4, acceleration waveform P1 is composed of positive acceleration A0 and acceleration time Ta, acceleration waveform P2 is composed of negative acceleration A0 and acceleration time Ta, and acceleration waveform P3 is composed of positive acceleration A0 and acceleration time Ta. By multiplying and adding up these positive or negative acceleration A0 and acceleration time Ta, the result is acceleration A0 x acceleration time Ta (positive speed), making it possible to achieve a target speed that is faster than the current speed.

On the other hand, if the target speed is slower than the current speed (target speed < current speed), then, contrary to the example in Figure 4, acceleration waveform P1 is composed of negative acceleration A0 and acceleration time Ta, acceleration waveform P2 is composed of positive acceleration A0 and acceleration time Ta, and acceleration waveform P3 is composed of negative acceleration A0 and acceleration time Ta. By multiplying and adding up these negative or positive acceleration A0 and acceleration time Ta, the result is negative acceleration A0 x acceleration time Ta (negative speed), making it possible to achieve a target speed that is slower than the current speed.

<Speed change process>
Next, a speed change process based on the above-mentioned principle will be described. In this example, the horizontal moving device H moves at a constant speed by speed control with a constant acceleration at one speed step.

(Speed change process)
The speed change process of the horizontal movement device H will be described with reference to the flow chart of Fig. 6. When the control unit 31 detects that the power supply to the device is turned on in step S10, the control unit 31 executes a start-up process for the crane system in step S11.

Next, in step S12, the lift control unit 51 receives the "up" or "down" operation command from the operation unit 8 and/or various commands and signals from the operation control unit 21, and executes drive control of the electric hoist 7.

Next, in step S13, the control unit 31 starts a pendulum period update process. Here, the period Tf is calculated from the rope length L based on the formula (1) and stored in the storage unit 32. g is the gravitational acceleration.

FIG. 7 is a diagram showing rope length L. In the example of FIG. 7, rope length L is calculated by subtracting center of gravity correction value w, which indicates the distance from the bottom of the load to the center of gravity position, from the sum of length k1 of rope 11 obtained from motor rotation speed information acquired by encoder 71, length k2 of the hook of electric hoist 7, which is an accessory, and length k3 from the hook to the load.

The position of the center of gravity of a suspended load changes depending on the shape of the load. If the load is uniform and predetermined, the center of gravity correction value w can be set as a specified value by default. Also, the operator can input the center of gravity correction value w by visually estimating the distance from the hook to the center of gravity of the load based on the shape of the load, and correct the center of gravity position.

When an action that changes the rope length L is performed, such as winding up or down the rope 11, which changes the length k1 of the rope 11, the rope length L is calculated and the period Tf is updated in step S13.

Next, in step S14, when the detection unit 41 detects a change in the target speed command (signal) from the operation unit 8, it stores the time t0 at which the change in the target speed command was detected in the memory unit 32 and updates the target speed stored in the memory unit 32. Specifically, when the detection unit 41 inputs a target speed command from the operation unit 8, it determines whether the target speed indicated therein matches the target speed stored in the memory unit 32, and if they do not match, it stores the target speed indicated by the input target speed command in place of the target speed stored in the memory unit 32. For example, when the horizontal direction push button switch is pressed while the horizontal movement device H is stopped, the target speed indicated in the target speed command input from the operation unit 8 is a predetermined speed Vm for moving the horizontal movement device H at a constant speed. At this timing, the speed of zero when stopping the horizontal movement device H is stored in the memory unit 32 as the target speed, so it is determined that the two do not match, and the target speed stored in the memory unit 32 is updated to the speed Vm. Furthermore, when the horizontal push button switch is pressed and the horizontal movement device H is moving at a constant speed, if the hand is released from the horizontal push button switch and the horizontal push button switch is no longer pressed, the target speed indicated in the target speed command input from the operation unit 8 is zero. At this timing, the speed Vm is stored in the memory unit 32 as the target speed, so it is determined that the two do not match, and the target speed stored in the memory unit 32 is updated to zero. Step S14 corresponds to the target speed update step.

Next, in step S15, the acceleration waveform determination unit (acceleration time determination unit) 42 calculates the acceleration time Ta of the three acceleration waveforms P1 to P3 based on the formula (2). The acceleration waveform determination unit 42 corresponds to the acceleration time determination unit. In the case of uniform acceleration control, the acceleration waveform can be determined by determining the magnitude of acceleration and the acceleration time. The acceleration A0 is the acceleration output by the horizontal movement device H, and is stored in the storage unit 32 as a parameter.
Acceleration time Ta=|Current speed of horizontal moving device H−Target speed|/Acceleration A0 (2)
The first acceleration waveform P1 and the third acceleration waveform P3 are waveforms with an acceleration time Ta at an acceleration A0, and the second acceleration waveform P2 is an acceleration waveform obtained by inverting the first acceleration waveform P1 and the third acceleration waveform P3. Step S15 corresponds to an acceleration waveform determination step.

Next, in step S16, the timing determination unit 43 determines times t1 to t3, which are the acceleration start timings of the three acceleration waveforms P1 to P3, based on equation (3). These timings are the timings at which the vibration waveform of the pendulum vibration of the suspended load, which is generated when the horizontal movement device H is driven by each of the three acceleration waveforms P1 to P3, is shifted by 1/3 period (120 degrees) of the vibration period Tf.
t1=t0+c
t2=t1+Tf/6
t3=t2+Tf/6
...(3)
t0 is the time when the target speed is updated (step S14).
t1 is the time indicating the acceleration start timing of the first acceleration waveform P1 (FIG. 4), and c is the delay time required until the horizontal movement device H is driven in step S19 described later. However, since this delay time is negligibly short compared to the period Tf of the suspended load, it will be ignored in the following explanation, and time t1 is regarded as the same time as time t0.
Tf is the period of pendulum oscillation of the suspended load calculated based on equation (1).
t2 is a time indicating the acceleration start timing of the second acceleration waveform P2, and is a time ⅙ of the period Tf of the vibration waveform n1 that has elapsed from time t1.
t3 is a time indicating the acceleration start timing of the third acceleration waveform P3, and is a time ⅙ of the period Tf of the vibration waveform n1 that has elapsed from time t2.
The second acceleration waveform P2 is an inverted acceleration waveform with respect to the first acceleration waveform P1 and the third acceleration waveform P3, and therefore generates an inverted vibration waveform (a vibration waveform shifted by 1/2 period) with respect to the vibration waveform generated by the non-inverted acceleration waveform. As a result, the vibration waveform n2 generated by the second acceleration waveform P2 is a vibration waveform shifted by 1/3 of the period Tf from the vibration waveforms n1 and n3 (FIG. 4). The acceleration start timing of the second acceleration waveform P2 is shifted by a period Tf/6 from the first acceleration waveform P1 and the third acceleration waveform P3. Step S16 corresponds to a timing determination step.

In step S17, the first to third acceleration waveforms P1 to P3 are arranged at the acceleration start timing determined in step S16 in an acceleration direction according to the magnitude of the current speed and target speed of the horizontal movement device H to generate an acceleration command signal. If the target speed is faster than the current speed of the horizontal movement device H (target speed > current speed of the horizontal movement device H), the first acceleration waveform P1 is acceleration in the positive direction, the second acceleration waveform P2 is acceleration in the negative direction, and the third acceleration waveform P3 is acceleration in the positive direction. If the target speed is slower than the current speed of the horizontal movement device H (target speed < current speed of the horizontal movement device H), the first acceleration waveform P1 is acceleration in the negative direction, the second acceleration waveform P2 is acceleration in the positive direction, and the third acceleration waveform P3 is acceleration in the negative direction.

The acceleration waveform can be composed of three time functions f1(t), f2(t), and f3(t) shown below.

If the target speed is faster than the current speed of the horizontal moving device H,
The time function f1(t) is
For t<t1, t>t1+Ta, f1(t)=0,
In the range of t1≦t≦t1+Ta, the first acceleration waveform P1 is a rectangular wave where f1(t)=A0.
The time function f2(t) is
For t<t2, t>t2+Ta, f2(t)=0.
In the range of t2≦t≦t2+Ta, the second acceleration waveform P2 is a square wave where f2(t)=−A0,
The time function f3(t) is
For t<t3 and t>t3+Ta, f3(t)=0.
In the range of t3≦t≦t3+Ta, the third acceleration waveform P3 is a square wave where f3(t)=A0.

If the target speed is slower than the current speed of the horizontal moving device H,
The time function f1(t) is
For t<t1, t>t1+Ta, f1(t)=0,
In the range of t1≦t≦t1+Ta, the first acceleration waveform P1 is a rectangular wave where f1(t)=−A0.
The time function f2(t) is
For t<t2, t>t2+Ta, f2(t)=0.
In the range of t2≦t≦t2+Ta, the second acceleration waveform P2 is a square wave where f2(t)=A0.
The time function f3(t) is
In the intervals t<t3 and t>t3+Ta, f3(t)=0.
When t3≦t≦t3+Ta, the third acceleration waveform P3 is a rectangular wave where f3(t)=−A0.

When the acceleration waveform is generated as a function of time in this way, the acceleration command signal generating unit 44 generates an acceleration command signal by adding up the acceleration waveforms P1 to P3 for each time in step S17, and generates a speed command signal, which is a drive command signal, from the acceleration command signal in step S18. In step S19, this is supplied to the travel inverter 52 and the traverse inverter 53. The travel inverter 52 and the traverse inverter 53 of the movement control unit 22 output drive power to the travel motor 3a and the traverse motor 5a based on the speed command signal, which is a drive command signal, from the operation control unit 21. As a result, the horizontal movement device H equipped with the electric hoist 7 is driven in the horizontal direction. The acceleration command signal can also be used as a drive command signal, and can be output to the travel inverter 52 and the traverse inverter 53 to control the speed. Step S17 corresponds to the acceleration command signal generating step, and steps S18 and S19 correspond to the drive control step.

Next, in step S20, the control unit 31 determines whether or not an emergency stop command has been issued, and if it is determined that an emergency stop command has not been issued, the process returns to step S12 and repeats the same process. If it is determined in step S20 that an emergency stop command has been issued, the control unit 31 executes a process to emergency stop the operation of the crane 1 in step S21, and the drive control of the crane system ends.

Note that we have omitted the explanation of the case where the electric hoist is driven during the process of changing the movement speed of the horizontal movement device H, causing the rope length L to fluctuate and the pendulum period Tf to fluctuate. Because the speed of the electric hoist used in the crane is slow, the rope length that fluctuates during the process of changing the movement speed of the horizontal movement device H has little effect on the fluctuation of the pendulum period Tf and can be ignored. Alternatively, for the same reason, the pendulum period Tf can be calculated in accordance with the fluctuation of the rope length and the acceleration start times t1 to t3 of the acceleration waveforms P1 to 3 can be changed each time. In that case, when the process of changing the movement speed of the horizontal movement device H is completed, the acceleration time may fluctuate, potentially resulting in an error with the target speed, so it is preferable to correct the error.

(Specific example)
The above-mentioned speed control process will now be described based on a specific example.
When, for example, the "East" push button switch is pressed from a stopped state, an acceleration time Ta is calculated based on equation (2) to determine an acceleration waveform from the speed difference between the current speed (zero speed) of the horizontal movement device H and the target speed Vm (step S15). Acceleration start timings t1 to t3 of three acceleration waveforms P1 to P3 are determined based on equation (3) from the timing at which the target speed was updated (step S14) and the period Tf of the pendulum oscillation (step S13) (step S16). Then, as shown on the left side of FIG. 8A, an acceleration waveform P1 consisting of a positive acceleration A0 (acceleration in the direction in which the horizontal moving device H moves (the "east" direction)) and an acceleration time Ta, an acceleration waveform P2 consisting of a negative acceleration A0 (acceleration in the direction opposite to the direction in which the horizontal moving device H moves (the "west" direction)) and an acceleration time Ta, and an acceleration waveform P3 consisting of a positive acceleration A0 and an acceleration time Ta are arranged at times t1 to t3, respectively, and the acceleration waveforms P1 to P3 are added together for each time, and an acceleration command signal shown on the left side of FIG. 8B is generated (step S17).

Then, as shown on the left side of Figure 8C, a speed command signal, which is a drive command signal, is generated from the acceleration command signal (step S18), and the speed command signal (drive command signal) is output to the travel inverter 52 to drive the travel motor 3a, causing the travel carriage 3 (horizontal movement device H) to move horizontally (step S19).

In other words, first, the stopped traveling cart 3 (horizontal movement device H) is accelerated in the "east" direction and begins to move, reaching a speed of Vm. At time t2, it is accelerated in the "west" direction, decelerating and reaching zero. At time t3, it is accelerated again in the "east" direction, after which the vibration of the suspended load is suppressed and the load moves at a constant speed of a predetermined speed. In addition to suppressing the vibration of the suspended load, the speed of the traveling cart 3 (horizontal movement device H) goes up and down along the way but does not move in reverse, making this speed control ideal for cranes, etc.

In addition, when the "East" push button switch continues to be pressed and the horizontal movement device H is moving in the "East" direction at a constant speed Vm, if the hand is released from the "East" push button switch and the "East" push button switch is no longer pressed, the acceleration time Ta for determining the acceleration waveform is calculated based on equation (2) from the speed difference between the current speed (speed Vm) and the target speed (speed zero) of the horizontal movement device H (step S15).The acceleration start timings t1 to t3 of the three acceleration waveforms P1 to P3 are determined based on equation (3) from the timing when the target speed was updated (step S14) and the period Tf of the pendulum oscillation (step S12) (step S16). Then, as shown on the right side of FIG. 8A, an acceleration waveform P11 consisting of a negative acceleration A0 (acceleration in the "west" direction opposite to the "east" direction in which the horizontal movement device H is moving) and an acceleration time Ta, an acceleration waveform P12 consisting of a positive acceleration A0 (acceleration in the "east" direction in which the horizontal movement device H is moving) and an acceleration time Ta, and an acceleration waveform P13 consisting of a negative acceleration A0 and an acceleration time Ta are arranged at times t1 to t3, respectively, and the acceleration waveforms P11 to P13 are added together at each time to generate the acceleration command signal shown on the left side of FIG. 8B (step S17).

Then, as shown on the right side of Figure 8C, a speed command signal, which is a drive command signal, is generated from the acceleration command signal (step S18), and the speed command signal (drive command signal) is output to the travel inverter 52 to drive the travel motor 3a, and the travel carriage 3 (horizontal movement device H) stops (step S19).

In other words, first, the traveling cart 3 moving in the "east" direction is accelerated in the "west" direction, decelerating and reaching a speed of zero. At time t2, acceleration is applied in the "east" direction, increasing the speed and reaching speed Vm. At time t3, acceleration is applied again in the "west" direction, after which the vibration of the suspended load is suppressed and the cart comes to a halt. In this case as well, the speed of the traveling cart 3 (horizontal movement device H) goes up and down along the way, but it does not run in reverse.

(Example of acceleration waveform signal)
Since the acceleration time Ta has a relationship based on the equation (2) with the speed difference between the current speed and the target speed of the horizontal movement device H and the acceleration A0, the acceleration time Ta becomes longer as the speed difference between the current speed and the target speed of the horizontal movement device H becomes larger. Also, as described above, the period Tf of the pendulum oscillation generated in the load by the drive of the horizontal movement device H by the first to third acceleration waveforms P1 to P3 is determined by the rope length L based on the equation (1), so the period Tf becomes shorter as the rope length L becomes shorter. Therefore, depending on these conditions, the first to third acceleration waveforms P1 to P3 may overlap each other, as shown in Figures 9 and 10.

In the example of Figure 9A, the start time t2 of the second acceleration waveform P2 is a time before the acceleration end time (t1+Ta) of the first acceleration waveform P1. The acceleration waveform signals of the first to third acceleration waveforms P1, P2, and P3 shown in Figure 9A, which are arranged at their respective start times t1 to t3, are added together for each time to generate the acceleration command signal shown in Figure 9B, and the speed command signal shown in Figure 9C, which is a drive command signal, is generated based on the acceleration command signal.

In the example of FIG. 10A, the start time t2 of the second acceleration waveform P2 and the start time t3 of the third acceleration waveform P3 are before the acceleration end time (t1+Ta) of the first acceleration waveform P1. When the acceleration waveform signals shown in FIG. 10A are added up at each time, an acceleration command signal shown in FIG. 10B is generated, and a speed command signal, which is a drive command signal, shown in FIG. 10C is generated based on the acceleration command signal. In this example, when a stopped horizontal movement device H is moved at a constant speed, apparent acceleration in one direction is performed three times at a predetermined timing, and deceleration, which is acceleration in the opposite direction, is not performed (left side of FIG. 10C). Similarly, when a horizontal movement device H is stopped during constant speed movement, apparent deceleration is performed three times at a predetermined timing, and no acceleration is performed (right side of FIG. 10C).

The acceleration waveforms in the examples of Figures 8 to 10 have been described as rectangular waves indicating a constant acceleration command, but the acceleration waveform is not limited to a rectangular wave. Figure 11 shows an example other than a rectangular wave. The example shown on the left side of Figure 11 shows an example of an acceleration waveform that is trapezoidal (constant jerk), and the example shown on the right side of Figure 11 shows an example of an acceleration waveform that is split. The acceleration waveform may also be a curved waveform (not shown).

Furthermore, a low-pass filter or the like can be used as a filter to remove minute vibrations. The low-pass filter may perform low-pass filtering on the drive command signal that the drive control unit 45 gives to the traveling inverter 52 and the traverse inverter 53, or may perform low-pass filtering before adding up the acceleration waveforms. The speed command before this low-pass filtering is shown in FIG. 12A, and the speed command after the low-pass filtering is shown in FIG. 12B. Such low-pass filtering can also be added to further improve the vibration suppression effect.

<Other examples of acceleration start timing>
In addition to the mode shown in Fig. 4, the phases of the vibration waveforms n1 to n3 are shifted by 120 degrees from each other in the case shown in Fig. 13. The speed control shown in Fig. 13 is also a speed control with a constant acceleration A0, like Fig. 3. Once the target speed Vm is determined, the acceleration time Ta is calculated.

The second acceleration waveform P2 starts accelerating at time t2, which is 1/3 of the period Tf of the vibration waveform n1 from the acceleration start time t1 of the first acceleration waveform P1. The third acceleration waveform P3 starts accelerating at time t3, which is 1/3 of the period Tf of the vibration waveform n1 from the acceleration start time t2 of the second acceleration waveform P2. The first to third acceleration waveforms P1, P2, and P3 shown in FIG. 13 are all acceleration waveforms in the same direction, so each acceleration time is set to 1/3 of Ta so that the speed of the horizontal movement device H at the end of the acceleration of the third acceleration waveform P3 becomes the target speed Vm.

The vibration waveforms n1 to n3 shown in FIG. 13 are also shifted in phase by 120 degrees, so the amplitude of the combined waveform becomes zero when acceleration by the third acceleration waveform P3 ends.

FIG. 13B shows an acceleration command signal obtained by adding up the acceleration waveforms P1 to P3 in FIG. 13A for each time, and FIG. 13C shows a speed command signal (drive command signal) generated based on the acceleration command signal.

If the target speed is faster than the current speed (target speed > current speed), as shown on the left side of Figure 13B, the first acceleration waveform P1 is composed of a positive acceleration A0 and an acceleration time Ta/3, the second acceleration waveform P2 is composed of a positive acceleration A0 and an acceleration time Ta/3, and the third acceleration waveform P3 is composed of a positive acceleration A0 and an acceleration time Ta/3. By multiplying and adding up these positive accelerations A0 and acceleration time Ta/3 to give acceleration A0 x acceleration time Ta (positive speed), a target speed that is faster than the current speed can be achieved.

On the other hand, when the target speed is slower than the current speed (target speed < current speed), as shown on the right side of Figure 13B, the first acceleration waveform P1 is composed of negative acceleration A0 and acceleration time Ta/3, the second acceleration waveform P2 is composed of negative acceleration A0 and acceleration time Ta/3, and the third acceleration waveform P3 is composed of negative acceleration A0 and acceleration time Ta/3. By multiplying and adding up these negative accelerations A0 and acceleration time Ta, the result is negative acceleration A0 x acceleration time Ta (negative speed), making it possible to achieve a target speed that is slower than the current speed.

<Supports multiple speeds>
Although the above description has been given of an example in which the constant speed is set to one level, there are also cranes 1 that can set the speed in two levels.

Pressing the push button once will move the horizontal movement device H at a "low" speed Vl, and pressing it twice will move it at a "high" speed Vh with constant acceleration. When the push button is not pressed, it will be "stopped" (zero speed).

Next, we will explain the speed change process in crane 1, which controls the speed with constant acceleration and allows speed setting in two stages, with reference to the flowchart in Figure 14.

Steps S50 to S53 and steps S55 to S62 are similar to steps S11 to S13 and steps S14 to S21 in FIG. 7, so their explanation will be omitted. In the case of this two-stage speed control, the operator presses the first stage of the horizontal push button switch and the up/down push button switch on the operation unit 8 to enter the low speed state, and then presses the second stage to change from low speed to high speed.

FIG. 15 shows an example in which the horizontal movement device H is controlled at two speed stages, "low speed" and "high speed". The leftmost part of FIG. 15 shows a signal when the horizontal movement device H in a stopped state is moved at a constant speed of "low speed". The center part of FIG. 15 shows a signal when the horizontal movement device H, which is moving at a constant speed at "low speed", is moved at a constant speed of "high speed". If the acceleration A0 that the horizontal movement device H can output is constant, when changing from a "stopped" to a "low speed" constant speed movement state, the first to third acceleration waveforms P11, P21, and P31 of Ta1, which have short acceleration times, are placed at the respective start times t11 (t1), t21 (t2), and t31 (t3), and are added up for each time to generate the acceleration command signal shown in FIG. 15B, and the speed command signal (drive command signal) shown in FIG. 15C is generated. When moving from a "low speed" to a "high speed" constant speed state, the first to third acceleration waveforms P12, P22, and P32 of Ta2, which have a long acceleration time, are arranged at the start times t12 (t1), t22 (t2), and t32 (t3), respectively, and are summed up at each time to generate the acceleration command signal shown in FIG. 15B, and the speed command signal (drive command signal) shown in FIG. 15C is generated. Even in such a case, the target speed can be obtained with the vibration of the suspended load suppressed. The right end of FIG. 15 shows an acceleration waveform signal when stopping the horizontal moving device H during a "high speed" constant speed movement. The acceleration time Ta3 represents the acceleration (deceleration) time required for the horizontal moving device H to move from "high speed" to "stop" (zero speed) with a negative acceleration A0. The first to third acceleration waveforms P13, P23, and P33, whose acceleration time is Ta3, are placed at their respective start times t13 (t1), t23 (t2), and t33 (t3), and are added up at each time to generate the acceleration command signal shown in FIG. 15B, and the speed command signal (drive command signal) shown in FIG. 15C. The start times of the acceleration waveforms are set based on the time when the speed change command is detected, so start times t11, t12, and t13 correspond to start time t1, start times t21, t22, and t23 correspond to start time t2, and start times t31, t32, and t33 correspond to start time t3.

In step S54, the detection unit 41 determines whether or not a speed change process is in progress. Specifically, at the timing when the detection unit 41 detects a change in the target speed command, the detection unit 41 determines whether the acceleration by the third acceleration waveform P3 in the ongoing speed change process to the pre-change target speed has not ended (speed change process in progress) or has ended (speed change process ended). That is, in step S54, if the current time is greater than the time (t3+Ta) at which acceleration by the third acceleration waveform P3 ends, the detection unit 41 determines NO, and proceeds to step S55 to execute the same process as that from step S14 onward in FIG. 7, which updates the update time t0.

In principle, target speed changes are not performed during speed change processing, but are permitted as an exception from step S63 onwards. Specifically, if it is determined in step S54 that speed change processing is in progress (YES), that is, if it is determined that the time (t1) at which acceleration by the first acceleration waveform P1 starts ≦ current time ≦ time at which acceleration by the third acceleration waveform P3 ends (t3 + Ta), the process proceeds to step S63, where the detection unit 41 determines whether the target speed change is to "stop" during speed change processing from "stop" to "low speed", the target speed change is to "stop" during speed change processing from "stop" to "high speed", or the target speed change is to "stop" during speed change processing from "low speed" to "high speed".

If the answer is YES in step S63, the process proceeds to step S64, where the detection unit 41 permits the target speed to be changed and updates the target speed to 0. Then, the acceleration waveform determination unit 42 calculates a corrected acceleration time Tas for stopping from the current speed Vc and the acceleration A0 based on the following formula.
Tas = Vc/A

In step S65, the acceleration command signal generating unit 44 generates the following time function fs(t) for stopping based on the calculated corrected acceleration time Tas for stopping.
For t≦ts+Tas, fs(t)=−A0,
For t>ts+Tas, fs(t)=0 square wave

Then, the acceleration command signal generating unit 44 replaces the time function f1(t) representing the first acceleration waveform P1 with the stop time function fs(t). That is, the time function f1(t) is expressed as follows:
For t≦ts+Tas, f1(t)=−A0,
When t>ts+Tas, f1(t)=0 becomes a square wave.

Further, the acceleration command signal generating unit 44 rewrites the time function f2(t) representing the second acceleration waveform P2 and the time function f3(t) representing the third acceleration waveform P3 as follows:
f2(t)=f3(t)=0
Proceed to the next step S59.

If the answer is NO in step S63, the process proceeds to step S66, where the detection unit 41 determines whether the target speed is changed to "low speed" during the speed change process from "high speed" to "stop", or whether the target speed is changed to "high speed" during the speed change process from "stop" to "low speed". If the answer is YES in step S66, the detection unit 41 determines in step S67 whether the current time is before the acceleration end time (t1+Ta) of the first acceleration waveform P1 and before the acceleration start time t2 of the second acceleration waveform P2 in the speed change process being executed.

If the answer is YES in step S67, in step S68, the detection unit 41 permits the change of the target speed and updates the target speed. Then, the acceleration waveform determination unit 42 calculates a corrected acceleration time Tas for changing the speed from the high speed Vm2 and the low speed Vm1 or the stop speed 0 based on the following formula.
Tas = (Vm2 - Vm1 or 0) / acceleration A0
The acceleration waveform determination unit 42 changes the value of the acceleration time Ta generated in the speed change process being executed to the value of the corrected acceleration time Tas, and proceeds to step S58. Therefore, the determination of the start timing of the acceleration waveform in step S57 is not executed, and the acceleration command signal is generated in step S58 using the times t1 to t3 before correction.

If the answer is NO in step S66, the process proceeds to step S69, where the detection unit 41 determines whether the target speed is being changed to "low speed" during the speed change process from "high speed" to "stop". If the answer is YES in step S69, the process proceeds to step S70, where the acceleration time (corrected acceleration time Tas) required to change the speed from "high speed" to "low speed" is calculated, and the process proceeds to step S71.

In step S71, the detection unit 41 determines whether the current time is before the start time t2 of the second acceleration waveform P2 and before the acceleration end time (t1+Tas) of the changed first acceleration waveform P1. If the answer is YES in step S71, the process proceeds to step S68 and the same process as described above is executed.

If the answer is NO in steps S67, S69, and S71, the process proceeds to step S59, where even if the speed command (signal) from the operation unit 8 is changed, vibration suppression control continues based on the command (signal) before the change until the time (t3+Ta) when execution of the third acceleration waveform P3 ends.

<Examples of use other than as a crane>
The above embodiment has been described as an example of suppressing and controlling the vibration of a load suspended from a crane 1, using an overhead crane as an example, but the present invention is not limited to vibration control of a load suspended from an overhead crane. The present invention can be applied to vibration control of a moving object that generates simple harmonic motion, such as an XY table of a processing machine, which is equipped with perpendicular running rails and traverse rails and can move to any position on the XY plane. In addition, the present invention can be applied to vibration control of a transport cart that runs while suspending a load, or to vibration control of a device that is not limited to a suspended load and that induces a natural vibration with a long period compared to the acceleration time when driven.

In the above embodiment, the explanation has been given mainly on the constant acceleration waveform, but the acceleration waveform is not limited to the constant acceleration waveform as shown in Fig. 11. When changing the speed, the acceleration waveform serving as a reference for generating the acceleration waveforms P1 to P3 is set as a time function f0(t),
Time indicating the acceleration start timing of the first acceleration waveform P1: t1
Time indicating the acceleration start timing of the second acceleration waveform P2: t2=t1+Tf/6
Time indicating the acceleration start timing of the third acceleration waveform P3: t3=t1+Tf/3
Natural vibration period: Tf
Time function representing the first acceleration waveform P1: f1(t)
Time function representing the second acceleration waveform P2: f2(t)
Time function representing the third acceleration waveform P3: f3(t)
Then,
The first acceleration waveform P1 is f1(t)=f0(t-t1).
The second acceleration waveform P2 is f2(t)=-f0(t-t2)=-f0(t-t1-Tf/6).
The third acceleration waveform P3 is f3(t)=f0(t-t3)=f0(t-t1-Tf/3).
It is expressed as
If the acceleration command obtained by combining the first to third acceleration waveforms P1 to P3 is a time function fc(t), then
fc(t)=f1(t)+f2(t)+f3(t)=f0(t-t1)-f0(t-t1-Tf/6)+f0(t-t1-Tf/3)
It can be expressed as:

[Summary of effects]
(1) As described above, the operation control unit 21 controls the speed of the drive device that moves the horizontal movement device from which the load is suspended in the horizontal direction based on the acceleration command signal.
a detection unit 41 which is a target speed update unit that detects a target speed change command for changing a target speed of the horizontal moving device H and updates the target speed;
an acceleration waveform determination unit 42 that determines first to third acceleration waveforms for generating an acceleration command signal based on a speed difference between the target speed updated by the detection unit 41 and the current speed of the horizontal movement device H;
a timing determination unit 43 that determines the start timings of three acceleration waveforms so that the phases of the vibration waveforms of the suspended load generated when the horizontal movement device H is driven by each of the three acceleration waveforms determined by the acceleration waveform determination unit 42 are shifted by 1/3;
an acceleration command signal generating unit 44 that generates an acceleration waveform signal indicating that the acceleration of the three acceleration waveforms starts at the timing determined by the timing determining unit;
and a drive control unit 45 for driving the horizontal movement device H based on the acceleration waveform signal.

This allows the horizontal movement device H and the suspended load to be moved at a target speed (including zero speed) while suppressing the swaying of the load. Driving the horizontal movement device H at the timing of each of the above-mentioned acceleration patterns can also be achieved by the operator operating the on/off switch of the operation unit 8 to turn the horizontal movement device H on and off, but it is difficult to always operate the on/off switch of the operation unit 8 at that timing. Therefore, the control unit 31 is configured to generate a drive command signal for driving the horizontal movement device H at each of the above-mentioned timings, and by driving the horizontal movement device H with that drive command signal, it is possible to move the horizontal movement device H and the suspended load at the target speed while reliably suppressing the vibration of the suspended load.

(2) The drive control unit 45 can add up the acceleration waveform signals at each time to generate an acceleration command signal (Figure 8B) and drive the horizontal movement device H based on the acceleration command signal.

With this configuration, for example, depending on the distance from the horizontal movement device H to the suspended load, or the magnitude of acceleration that the horizontal movement device H can output, even when the acceleration waveform signals (FIGS. 9A and 10A) are arranged so that the acceleration waveforms overlap partially, it is possible to generate a drive command signal that achieves the target speed state while suppressing the swaying of the suspended load.

(3) The timing determination unit 43 determines that the time t1, which is the start timing of the first acceleration waveform, corresponds to the time when the detection unit 41 detects a change in the target speed,
The time t2, which is the start timing of the second acceleration waveform, is set to the time when 1/6 of the period of the vibration waveform of the suspended load generated when the horizontal movement device H is driven by the first acceleration waveform has elapsed from the time t1,
The time t3, which is the start timing of the third acceleration waveform, is set to the time when 1/6 of the period of the vibration waveform of the suspended load generated when the horizontal movement device H is driven by the first acceleration waveform has elapsed from the time t2,
The acceleration waveform determination unit 42 determines the first to third acceleration waveforms as uniform acceleration waveforms and an acceleration time from the target speed, generates the first acceleration waveform from a time function f1(t), generates the second acceleration waveform from a time function f2(t), and generates the third acceleration waveform from a time function f3(t);
If the target speed is faster than the current speed,
The time function f1(t) is
For t<t1, t>t1+Ta, f1(t)=0,
For t1≦t≦t1+Ta, f1(t)=A0 is a square wave.
The time function f2(t) is
For t<t2, t>t2+Ta, f2(t)=0.
For t2≦t≦t2+Ta, f2(t)=-A0, which is a square wave.
The time function f3(t) is
For t<t3 and t>t3+Ta, f3(t)=0.
For t3≦t≦t3+Ta, f3(t)=A0 is a square wave.
If the target speed is slower than the current speed,
The time function f1(t) is
For t<t1, t>t1+Ta, f1(t)=0,
For t1≦t≦t1+Ta, f1(t)=-A0 is a square wave.
The time function f2(t) is
For t<t2, t>t2+Ta, f2(t)=0.
For t2≦t≦t2+Ta, f2(t)=A0 is a square wave.
The time function f3(t) is
For t<t3 and t>t3+Ta, f3(t)=0.
For t3≦t≦t3+Ta, f3(t)=−A0 square wave.

　With this configuration, the vibrations converge 1/3 of the vibration period after the first acceleration waveform ends, and the shaking can be suppressed in a short time. The three acceleration waveforms for generating the acceleration command signal can be expressed as f1(t) = f3(t) = f0(t), f2(t) = -f0(t) from the basic acceleration waveform f0(t), i.e., the first acceleration waveform f1(t), the second acceleration waveform f2(t), and the third waveform f3(t), making it possible to easily generate the three acceleration waveforms.

(4) In addition, the timing determination unit 43
The first time t1, which is the start timing of the first acceleration waveform, is set to the time t1 corresponding to the timing when the detection unit 41 detects a change in the target speed, the second time t2, which is the start timing of the second acceleration waveform, is set to the time when 1/3 of the period of the vibration waveform of the suspended load generated when the horizontal movement device H is driven by the first acceleration waveform has elapsed from time t1, and the third time t3, which is the start timing of the third acceleration waveform, is set to the time when 1/3 of the period of the vibration waveform of the suspended load generated when the horizontal movement device H is driven by the first acceleration waveform has elapsed from time t2.
The acceleration waveform determination unit 42
The first to third acceleration waveforms are set as uniform acceleration waveforms, an acceleration time is determined from a target speed, the first acceleration waveform is generated from a time function f1(t), the second acceleration waveform is generated from a time function f2(t), and the third acceleration waveform is generated from a time function f3(t);
If the target speed is faster than the current speed,
The time function f1(t) is
For t<t1, t>t1+Ta/3, f1(t)=0,
When t1≦t≦t1+Ta/3, f1(t)=A0 is a square wave.
The time function f2(t) is
For t<t2, t>t2+Ta/3, f2(t)=0.
When t2≦t≦t2+Ta/3, f2(t)=A0 is a square wave.
The time function f3(t) is
For t<t3 and t>t3+Ta/3, f3(t)=0.
For t3≦t≦t3+Ta/3, f3(t)=A0 is a square wave.
If the target speed is slower than the current speed,
The time function f1(t) is
For t<t1, t>t1+Ta/3, f1(t)=0,
When t1≦t≦t1+Ta/3, f1(t)=-A0 is a square wave.
The time function f2(t) is
For t<t2, t>t2+Ta/3, f2(t)=0.
When t2≦t≦t2+Ta/3, f2(t)=−A0, which is a square wave.
The time function f3(t) is
For t<t3 and t>t3+Ta/3, f3(t)=0.
For t3≦t≦t3+Ta/3, f3(t)=−A0 square wave.

As a result, the composite acceleration and composite speed will never exceed the maximum acceleration of the device's reference acceleration pattern, will never exceed the target speed, and will never reverse direction (a speed negative to the target speed). By employing this method when stopping a crane or similar device, it is possible to perform stopping control that suppresses load sway by executing control that activates the electromagnetic brake at this timing, not only without using a power conversion device such as an inverter, but also without using a power conversion device.

(5) Two target speeds, high and low, are provided, and if the detection unit 41 detects a change in the target speed of the horizontal movement device H before the acceleration by the third acceleration waveform is completed, the detection unit 41 is able to not update the target speed.

This reduces the possibility that the operator will input a speed change command into the operation unit 8, and the target speed will be changed during the speed change process, resulting in failure to obtain vibration damping effects.

(6) Two target speeds, high and low, are provided, and the detection unit 41 can stop not updating the target speed and update the target speed under certain conditions.

(7) Two target speeds, a high speed and a low speed, are provided,
When a command to change the target speed to zero is detected before the acceleration by the third acceleration waveform for changing the target speed from zero to a low speed is completed,
When a command to change the target speed to zero is detected before the acceleration by the third acceleration waveform for changing the target speed from zero to a high speed is completed,
Or, when a command to change the target speed to zero is detected before the acceleration by the third acceleration waveform for changing the target speed from a low speed to a high speed is completed,
When the time when the command to change the target speed is detected is a time when the acceleration time Ta has not elapsed since the third time t3, the detection unit 41 stores a stop command time ts corresponding to the time when the target speed change command to set the target speed to zero was detected, and updates the target speed.
The acceleration waveform determination unit 42 determines a correction acceleration time Tas for stopping from the current speed of the driving device,
For t≦ts+Tas, fs(t)=−A0,
After generating a stop time function fs(t) that becomes a square wave with fs(t)=0 when t>ts+Tas,
Replace the time function f(t) with the time function f(t),
Time function f2(t)=0
Time function f3(t)=0
It can be said that:

This makes it possible to dampen the vibration of the suspended load without compromising the operability of the horizontal movement device H.

(8) The horizontal movement device H is a horizontal movement device H that drives the traveling motor 3a and the traverse motor 5a using a traveling inverter 52 and a traverse inverter 53,
The control unit 31 supplies the generated drive command signal to the traveling inverter 52 and the traverse inverter 53 to drive the horizontal movement device H.

This configuration allows the drive control of the horizontal movement device H, which is driven by the travel inverter 52 and the traverse inverter 53.

(9) The acceleration waveform is a rectangular waveform or a trapezoidal waveform (Figures 8 to 12).

This configuration makes it possible to suppress the swaying of the suspended load based on a wide variety of waveforms.

(10) The crane 1 can have an operation control unit 21. In this way, the swaying of the load suspended by the crane 1 can be suppressed.

REFERENCE SIGNS LIST 1 Crane 2 Travel rail 3 Travel cart 3a Travel motor 4 Girder 5 Trolley 5a Traverse motor 6 Lift motor 7 Electric hoist 8 Operation unit 9 Cable 10 Hook 11 Rope 21 Operation control unit 22 Movement control unit 31 Control unit 32 Memory unit 41 Detection unit 42 Acceleration waveform determination unit 43 Timing determination unit 44 Acceleration command signal generation unit 45 Drive control unit 51 Lift control unit 52 Travel inverter 53 Traverse inverter 54 Lift inverter 71 Encoder

Claims (14)

A control device that controls the speed of a drive device that moves a horizontal movement device from which a load is suspended in a horizontal direction based on an acceleration command signal,
a target speed update unit that detects a target speed change command for changing a target speed of the driving device and updates the target speed;
an acceleration waveform determination unit that determines three acceleration waveforms, i.e., a first acceleration waveform, a second acceleration waveform, and a third acceleration waveform, for generating the acceleration command signal, based on a speed difference between the target speed updated by the target speed update unit and a current speed of the drive device;
a timing determination unit that determines start timings of the three acceleration waveforms so that the phases of the vibration waveforms of the suspended load generated when the driving device is driven by each of the three acceleration waveforms are shifted by 1/3;
an acceleration command signal generating unit that generates the acceleration command signal indicating that the acceleration of the three acceleration waveforms starts at the timing determined by the timing determining unit;
a drive control unit that generates a drive command signal based on the acceleration command signal to drive the drive device. 2. The control device according to claim 1,
The control device according to claim 1, wherein the acceleration command signal generating unit generates the acceleration command signal by adding up the three acceleration waveforms for each time. 2. The control device according to claim 1,
The timing determination unit is
a first time t1, which is a start timing of the first acceleration waveform, is set to a time corresponding to a timing at which the target speed update unit detects a command to change the target speed;
A second time t2, which is the start timing of the second acceleration waveform, is set to a time when a time equivalent to 1/6 of the period of the vibration waveform of the suspended load generated when the driving device is driven by the first acceleration waveform has elapsed from the first time t1,
A third time t3, which is the start timing of the third acceleration waveform, is set to a time when 1/6 of the period of the vibration waveform of the suspended load generated when the driving device is driven by the first acceleration waveform has elapsed from the second time t2,
The acceleration waveform determination unit
The first to third acceleration waveforms are set as uniform acceleration waveforms with a predetermined acceleration A0, and an acceleration time Ta is determined from the target speed;
The first acceleration waveform is generated from a time function f1(t), the second acceleration waveform is generated from a time function f2(t), and the third acceleration waveform is generated from a time function f3(t);
If the target speed is greater than the current speed,
The time function f1(t) is
For t<t1, t>t1+Ta, f1(t)=0,
For t1≦t≦t1+Ta, f1(t)=A0 is a square wave.
The time function f2(t) is
For t<t2, t>t2+Ta, f2(t)=0.
For t2≦t≦t2+Ta, f2(t)=-A0, which is a square wave.
The time function f3(t) is
For t<t3 and t>t3+Ta, f3(t)=0.
For t3≦t≦t3+Ta, f3(t)=A0 is a square wave.
If the target speed is slower than the current speed,
The time function f1(t) is
For t<t1, t>t1+Ta, f1(t)=0,
For t1≦t≦t1+Ta, f1(t)=-A0 is a square wave.
The time function f2(t) is
For t<t2, t>t2+Ta, f2(t)=0.
For t2≦t≦t2+Ta, f2(t)=A0 is a square wave.
The time function f3(t) is
For t<t3 and t>t3+Ta, f3(t)=0.
The control device is characterized in that, for t3≦t≦t3+Ta, f3(t)=-A0 is a square wave. 2. The control device according to claim 1,
The timing determination unit is
a first time t1, which is a start timing of the first acceleration waveform, is set to a time corresponding to a timing at which the target speed update unit detects a command to change the target speed;
A second time t2, which is the start timing of the second acceleration waveform, is set to a time when 1/3 of the period of the vibration waveform of the suspended load generated when the driving device is driven by the first acceleration waveform has elapsed from the first time t1,
A third time t3, which is the start timing of the third acceleration waveform, is set to a time when 1/3 of the period of the vibration waveform of the suspended load generated when the driving device is driven by the first acceleration waveform has elapsed from the second time t2,
The acceleration waveform determination unit
The first to third acceleration waveforms are set as uniform acceleration waveforms with a predetermined acceleration A0, and an acceleration time Ta is determined from the target speed;
The first acceleration waveform is generated from a time function f1(t), the second acceleration waveform is generated from a time function f2(t), and the third acceleration waveform is generated from a time function f3(t);
If the target speed is greater than the current speed,
The time function f1(t) is
For t<t1, t>t1+Ta/3, f1(t)=0,
When t1≦t≦t1+Ta/3, f1(t)=A0 is a square wave.
The time function f2(t) is
For t<t2, t>t2+Ta/3, f2(t)=0.
When t2≦t≦t2+Ta/3, f2(t)=A0 is a square wave.
The time function f3(t) is
For t<t3 and t>t3+Ta/3, f3(t)=0.
For t3≦t≦t3+Ta/3, f3(t)=A0 is a square wave.
If the target speed is slower than the current speed,
The time function f1(t) is
For t<t1, t>t1+Ta/3, f1(t)=0,
When t1≦t≦t1+Ta/3, f1(t)=-A0 is a square wave.
The time function f2(t) is
For t<t2, t>t2+Ta/3, f2(t)=0.
When t2≦t≦t2+Ta/3, f2(t)=−A0, which is a square wave.
The time function f3(t) is
For t<t3 and t>t3+Ta/3, f3(t)=0.
The control device is characterized in that, for t3≦t≦t3+Ta/3, f3(t)=-A0 is a square wave. 5. The control device according to claim 3,
Two target speeds, a high speed and a low speed, are provided,
the target speed update unit does not update the target speed when it detects a command to change the target speed of the drive device before acceleration by the third acceleration waveform is completed. 6. The control device according to claim 5,
The control device according to claim 1, wherein the target speed update unit stops not updating the target speed under a predetermined condition and updates the target speed. 4. The control device according to claim 3,
Two target speeds, a high speed and a low speed, are provided,
When the target speed change command for changing the target speed to zero is detected before the acceleration by the third acceleration waveform for changing the target speed from zero to a low speed is completed,
When the target speed change command for changing the target speed to zero is detected before the acceleration by the third acceleration waveform for changing the target speed from zero to a high speed is completed,
or when a target speed change command for setting the target speed to zero is detected before the acceleration by the third acceleration waveform for changing the target speed from a low speed to a high speed is completed,
the target speed update unit, when the time at which the target speed change command for setting the target speed to zero is detected is a time that has not elapsed since the third time t3 within the acceleration time Ta, stores a stop command time ts corresponding to the time at which the target speed change command for setting the target speed to zero is detected, and updates the target speed to zero;
The acceleration waveform determination unit
determining a corrective acceleration time Tas for stopping from a current speed of the drive;
For t≦ts+Tas, fs(t)=−A0,
After generating a correction time function fs(t) for stopping, which is a square wave with fs(t)=0 when t>ts+Tas,
Replace the time function f(t) with the time function f(t),
The time function f2(t)=0
The control device is characterized in that the time function f3(t)=0. 3. The control device according to claim 2,
The drive device drives a motor using a power conversion device,
The drive control unit provides the generated drive command signal to the power conversion device to drive the drive device.
A control device comprising: 4. The control device according to claim 2 or 3,
The acceleration waveform is a rectangular waveform or a trapezoidal waveform.
A control device comprising: A crane having a control device according to any one of claims 1 to 3. A control method for a control device that controls the speed of a drive device that moves a horizontal movement device from which a load is suspended in a horizontal direction based on an acceleration command signal, comprising:
a target speed update step of detecting a command to change a target speed of the driving device and updating the target speed;
an acceleration waveform determination step of determining three acceleration waveforms, i.e., a first acceleration waveform, a second acceleration waveform, and a third acceleration waveform, for generating the acceleration command signal, based on a speed difference between the target speed updated in the target speed update step and a current speed of the driving device;
a timing determination step of determining start timings of the three acceleration waveforms so that the phases of the vibration waveforms of the load generated when the driving device is driven by each of the three acceleration waveforms determined in the acceleration waveform determination step are shifted by 1/3;
an acceleration command signal generating step of generating the acceleration command signal indicating that the acceleration of the three acceleration waveforms is to start at the timing determined in the timing determining step;
a drive control step of generating a drive command signal based on the acceleration command signal to drive the drive device. A vibration suppression control method for controlling the speed of a controlled object, which generates three acceleration command signals that induce three natural vibrations that are shifted from each other by 1/3 of the period of the natural vibration generated in the controlled object by the controlled speed, and reduces the natural vibrations by executing speed control of the controlled object. The vibration control method according to claim 12, characterized in that the natural vibration is a pendulum vibration. 13. The vibration damping control method according to claim 12, wherein the acceleration command signal is an acceleration command signal of a constant acceleration.

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