JP2000103592A - Control method for hoist crane device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a load from falling even when abnormality is generated in a mechanical brake device itself by returning control gain to an ordinary numerical value when the speed of an induction motor can not be maintained at zero rotation, and stopping drive by an inverter device when the speed of the induction motor is maintained at zero rotation. SOLUTION: When an induction motor is maintained at zero rotation after confirming operation of a mechanical brake device, at the timing inputting a signal confirming operation of the mechanical brake device, both integrated (Ki) gain and proportional (Kp) gain to be control gain of a speed control circuit are simultaneously began the stepdown. At the worst, when the induction motor can not be maintained at zero rotation in the stepdown process due to abnormality of the mechanical brake or the like, this method is constituted so that stepdown of the integrated (Ki) gain and the proportional (Kp) gain to be the control gain of the speed control circuit are stopped, and returned to the gain condition of an ordinary speed control circuit. Hereby, a load is controlled so as not to fall.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake device for hoisting and lowering a load of a hoist crane device, and more particularly to a method for controlling the hoist crane device when the operation is stopped.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram of a conventional hoist crane apparatus, and FIG. 5 is an operation timing chart of each part of a brake apparatus. In FIG. 4, reference numeral 1 denotes an induction motor, and 2 denotes an inverter device for controlling the induction motor 1 at a variable speed. Reference numeral 3 denotes a rotation detector for detecting the number of rotations of the induction motor 1, and reference numeral 8 denotes a speed command setting device to be input to the inverter device. A speed control circuit 9 generates a command for speed control from a speed command value input from the speed command setting device 8 and a rotation speed detection value of the induction motor input from the rotation detector 3. The output of the induction motor 1 is transmitted to a cable winding drum 13 through a mechanical brake device 11 and a speed reducer 12. The load 20 is lifted by the cable 14 and the hook 15, and is hoisted and lowered. Reference numeral 4 denotes a mechanical brake operation signal generator for giving an operation command to the mechanical brake device 11, and reference numeral 5 denotes a mechanical brake device 11 which is operated by receiving a command from the mechanical brake operation signal generator 4, and the hoist crane device is operated by the mechanical brake device 11 is a mechanical brake operating state signal output device indicating that the state is fixed by 11;

The operation of the conventional system will be described with reference to the apparatus shown in FIG. 4 and the timing chart of FIG. When the operation signal is turned off to stop the operation at time T10, the rotation of the induction motor 1 decreases, and the rotation speed of the induction motor 1 reaches 0 rotation at time T11. When the number of revolutions becomes zero, a signal for operating the mechanical brake device 11 is output from the zero revolution detector 6. Thereafter, at time T12, a signal indicating that the mechanical brake actually operates and is fixed by the mechanical brake device 11 is output from the mechanical brake operating state signal output unit 5. The time difference between the times T11 and T12 is because a response delay always occurs in the operation of the mechanical brake device 11, so that the operation of the induction motor 1 is not stopped until the time T12, and the load 20 is not dropped during the period from the time T11 to T12. The speed of the induction motor 1 is controlled at 0 rotation. At time T12, when a signal indicating that the induction motor 1 is in a fixed state is sent from the mechanical brake operation state signal output device 5 to the inverter device 2 and the timer 7, the inverter device 2 that has received this signal turns the induction motor 1 Is stopped, and at the same time, the timer 7 starts operating.

[0004] From the period T12 when the timer 7 operates to the time T1
At 3, the switch 30 is closed, and the output of the rotation detector 3 is sent to the comparator 32. The comparator 32 compares the rotation detection amount from the rotation detector 3 with the allowable rotation amount setting unit 31 that sets the rotation amount permitted for the induction motor 1 during operation stop, and determines whether the rotation detection amount is equal to the allowable rotation amount setting. When going over the vessel 31,
A signal is output as an abnormality of the mechanical brake device 11, and the mechanical brake device abnormality indicator 33 is configured to externally display the abnormality of the mechanical brake device.

[0005]

However, in the above-mentioned conventional hoist crane brake device, the mechanical brake device operates at time T12, and the load can be completely held by the mechanical brake device. It is difficult to judge. That is, the signal output from the mechanical brake operating state signal output device 5 is a signal indicating only that the brake shoe 111 has been operated and the mechanical brake has been fixed, and whether or not the mechanical brake is completely fixed. Cannot be determined only by the mechanical brake operation state signal. The reason for this is that a slip phenomenon may occur due to abnormal operation of the mechanical brake device itself or wear of the brake shoe 111. If the slip phenomenon occurs despite the operation of the mechanical brake device, the vehicle is lifted. The load may be dropped.

[0006] Further, the amount of rotation allowed for the induction motor during operation stop is set, and a mechanical brake device 1 is set by using a comparator.
In the method of outputting a signal as the abnormality of No. 1, since the abnormality of the mechanical brake device can be detected only during the period in which the timer operates, the allowable rotation amount set level is not reached during the timer operation period, and the mechanical braking is not performed. If a situation occurs in which rotation continues due to an abnormality in the device, the load may drop after the timer operation period has elapsed.

[0007]

In order to solve the above problems, the present invention provides an induction motor for driving a hoist crane for hoisting and lowering a load, an inverter device for controlling the induction motor at a variable speed, and the induction motor. A rotation detector for detecting the rotation state of the motor, a mechanical brake device for mechanically fixing the induction motor while the hoist crane is stopped, and the mechanical brake device is activated after the speed of the induction motor reaches 0 rotation when the operation is stopped. In a hoist crane device provided with a speed control circuit for controlling the speed of the induction motor at 0 rotation until the rotation of the induction motor, the speed of the induction motor is maintained at 0 rotation at the same time as the operation of the mechanical brake device. The control gain of the control circuit is configured to be reduced, and when the speed of the induction motor cannot be maintained at 0 rotation, the control gain is reduced. The said induction motor back to ordinary numeric configured to continue operation of the inverter device for driving, when the speed of the induction motor is maintained at 0 rotation is arranged to pause the driving by the inverter device.

In the above configuration, the integral component in the speed control circuit is fixed to zero, and the speed of the induction motor is controlled to zero rotation by a speed control system in which the output of the speed control circuit has only a proportional component. . After confirming the operation of the mechanical brake device, if the induction motor is maintained at zero rotation even if the integral component in the speed control circuit is fixed to zero during zero rotation control of the induction motor, the proportionality of the speed control circuit Construct a speed control circuit that reduces the component coefficient to zero in a fixed time period to continue zero-rotation control of the induction motor, and when the proportional component coefficient decreases to zero, operate the inverter device when the induction motor has zero rotation. Pause. At this time, if the induction motor is in a state where it is not held at 0 rotation while the proportional component coefficient is reduced to zero in a fixed time period, the reduction of the proportional component coefficient is stopped and the speed control is continued, and the induction motor is controlled in advance. When the rotation reaches the set mechanical brake device abnormality detection rotation amount, the integral component value and the proportional component coefficient of the speed control circuit are returned to the normal speed control circuit state, the induction motor is controlled to zero rotation, and the induction motor is driven by the inverter device. Continue driving.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a hoist crane device according to the present invention, FIG. 2 is an operation timing diagram of the hoist crane device, and FIG. FIG. 3 is a configuration diagram of a speed control circuit in which an integral component of the speed control circuit is fixed to zero and an output of the speed control circuit is only a proportional component. In FIG. 1, the same reference numerals as those in FIG. 4 denote the same functions and the same configurations, and a description thereof will be omitted.

The operation timing of the hoist crane device according to the present invention will be described with reference to FIG. FIG. 2A shows that after the operation of the mechanical brake device 11 is confirmed, the induction motor 1
FIG. 4 is a timing chart in the case where the rotation is maintained, and shows the method described in claim 1. In the figure, at the timing of inputting a signal for confirming the operation of the mechanical brake device, both the integral (Ki) gain and the proportional (Kp) gain, which are the control gains of the speed control circuit 9, are simultaneously started to gradually decrease. If the induction motor 1 cannot be maintained at 0 rotation due to a mechanical brake device abnormality or the like during the step-down process, the integral (Ki) gain, which is the control gain of the speed control circuit 9, is proportional to (K).
p) Control is performed so that the load does not drop by stopping the decrease in gain and returning to the gain state of the normal speed control circuit.

Next, claim 2 will be described. FIG.
(B) is a timing chart when the induction motor 1 in claim 2 is held at zero rotation. The figure shows that the integral (Ki) component control is set to zero at the timing of inputting a signal for confirming the operation of the mechanical brake device, and the proportional component coefficient of the speed control circuit 9 is reduced to zero in a fixed time period. FIG. 2C is a timing chart when the induction motor 1 is in a state where the induction motor 1 is not held at 0 rotation. The reduction of the proportional component coefficient is stopped, and the induction motor 1 presets the mechanical brake device abnormality detection rotation amount. The state in which the integral component and the proportional component of the speed control circuit 9 are returned to the normal state of the speed control circuit at the time when the motor is rotated to the maximum speed is shown. As described above, the first and second aspects differ from each other in that the integral gain Ki is immediately set to 0 or reduced in a fixed time period when a signal confirming the operation of the mechanical brake device is received. The same effect is obtained in that the load is not dropped by controlling the speed control circuit 9 to return to the state of the normal speed control circuit when the induction motor 1 cannot be maintained at 0 rotation due to a brake device abnormality or the like. .

Hereinafter, a specific embodiment will be described using the method and symbols described in claim 2. In FIG. 2B, at time T
When the operation signal is turned off at 0, the rotation of the induction motor 1 decreases, and when the rotation speed of the induction motor 1 reaches 0 rotation at time T1, the rotation of the induction motor 1 from the zero rotation detector 6 to which the signal of the rotation detector 3 is input is changed. A signal for starting the operation of the mechanical brake device is output to the brake operation signal generator 4, and a signal indicating that the induction motor 1 is fixed by the mechanical brake device 11 at time T2 is output to the mechanical brake operation state signal output device 5.
It is output to the switch 30 and the speed control circuit 9. The speed control circuit 9 is a circuit that performs speed control based on a deviation between the speed command setting device 8 and the rotation detector 3, and a differential amplifier 91.
And an integrator 93 that integrates the output of the differential amplifier 91 with time. The outputs of the multiplier 92 and the integrator 93 are added to the inverter device 2. Output to realize speed control.

At time T2, in the speed control circuit 9, the switch 94 is closed to the 0 side to fix the output of the integrator to 0, and the control command amount output to the inverter device 2 is made only the proportional component. At this time, since the integral of the deviation between the speed command setting device 8 and the rotation detector 3 is not added, the torque generated in the induction motor 1 is an amount proportional to the rotation of the induction motor 1. Here, if there is no abnormality in the mechanical brake device, the induction motor 1 should of course not rotate, and as shown in FIG. 2B, even if the proportional gain Kp is reduced to zero, the induction motor 1 does not rotate. When the proportional gain Kp becomes zero at the time T3, even if the operation of the inverter device 2 is stopped, the load is not dropped because it is fixed by the mechanical brake device.

When there is an abnormality in the mechanical brake device, it operates as shown in FIG. FIG. 2C shows an operation when the rotation of the induction motor 1 is detected while the proportional gain Kp is gradually reduced to zero in the state of FIG. 2B. When the rotation of induction motor 1 is detected, multiplier 92 sets proportional gain Kp
Is stopped, and when the rotation amount of the induction motor 1 has rotated to a predetermined mechanical brake device abnormality detection rotation amount, the switch 94 of the speed control circuit 9 is returned to a normal state, and the integrator 9 is returned.
In addition to outputting the integral value of 3, the proportional gain Kp of the multiplier 92 is also returned to the normal value, and the load is held by the normal zero speed control.

By gradually decreasing the proportional gain Kp during the zero speed control, the torque generated by the induction motor gradually decreases. If there is an abnormality in the mechanical brake device, the load cannot be held by the torque of the induction motor and the mechanical brake device. Then, the rotation amount of the induction motor gradually increases. Therefore, it is possible to simultaneously check the load holding capacity of the mechanical brake device, and by continuing the operation of the inverter device when the load cannot be held by the mechanical brake device alone, even if an abnormality occurs in the mechanical brake device. It is possible to prevent the load from dropping.

[0016]

As described above, according to the present invention, when the operation of the hoist crane device is stopped, the state in which the mechanical brake device is operating is detected, and the operation of the inverter device for driving the hoist crane device is performed. Even in the case where the mechanical brake device is configured to stop, it is possible to provide a safe hoist crane device capable of preventing a load from falling even if an abnormality occurs in the mechanical brake device itself.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is an operation timing chart of the present invention.

FIG. 3 is a block diagram of a speed control circuit according to the present invention.

FIG. 4 is a block diagram showing a configuration of a conventional example.

FIG. 5 is an operation timing chart of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Induction motor 2 Inverter device 3 Rotation detector 4 Mechanical brake operation signal generator 5 Mechanical brake operation state signal output device 6 Zero rotation detector 7 Timer 8 Speed command setting device 9 Speed control circuit 11 Mechanical brake device 12 Reduction gear 13 Cable Winding drum 14 Cable 15 Hook 20 Load 30 Switch 31 Allowable rotation amount setting device 32 Comparator 33 Mechanical brake device abnormality indicator 111 Brake shoe_

Claims (2)

[Claims] 1. An induction motor for driving a hoist crane for hoisting and lowering a load, an inverter device for controlling the induction motor at a variable speed, a rotation detector for detecting a rotation state of the induction motor, and the induction when the operation of the hoist crane is stopped. When the operation of the hoist crane device having the mechanical brake device for mechanically fixing the electric motor and the above is stopped, the induction motor is kept at 0 for a period from when the speed of the induction motor reaches 0 rotation until the mechanical brake device is activated. In a hoist crane device equipped with a speed control circuit that controls speed by rotation,
The control gain of the speed control circuit is reduced to a limit point at which the speed of the induction motor can be maintained at zero rotation at the same time as the operation of the mechanical brake device, and if the speed of the induction motor cannot be maintained at zero rotation, A method for controlling a hoist crane device, wherein a control gain is returned to a normal value. 2. A speed control system wherein the integral component of the speed control circuit is fixed to zero at the same time as the operation of the mechanical brake device, and the output of the speed control circuit is only a proportional component,
When the induction motor is maintained at zero rotation, the proportional component coefficient of the speed control circuit is configured to be reduced to zero in a fixed time period, and when the induction motor is not maintaining zero rotation, the proportional component is reduced. 2. The method for controlling a hoist crane device according to claim 1, wherein the reduction of the coefficient is stopped.