JPH09194187A - Crane control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To materialize a coasting operation even if an inverter device and an squirrel-cage motor is used. SOLUTION: The crane control device is so constituted as to control the travelling or turn-over of a crane by applying the output of an AC power supply to an inverter device 2 converting the output into a specified voltage and a specified frequency, and applying the output of the inverter device 2 to a squirrel-cage motor 3 for executing speed control. In this case, the crane device is also equipped with an acceleration/deceleration limiting circuit 4 providing a speed reference for the inverter device 2, which changes the speed of the squirrel-cage motor 3 at a certain definite change rate when a command for a high speed operation, a command for a low speed operation or a command for suspension is given, and with a coasting deceleration limiting circuit 5 providing a speed reference for the inverter 2, which is connected with the acceleration/deceleration limiting circuit 4 in parallel, and decelerates the speed of the squirrel-cage motor 3 at a deceleration rate identical to that of free-run at the time of coasting operations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crane control device for controlling turning and running during a coasting operation among several crane operations.

[0002]

2. Description of the Related Art Conventionally, as a jib crane used for cargo handling, civil engineering and construction work, as shown in FIG. 2, a swivel part 32 provided at an upper part of a support tower 31 having a movable tower shape is capable of expanding and contracting. 33 is provided so as to project, and a wire 35 that is fed or wound by a hoist 34 is hung at the tip of the jib 33.

In the operation of such a jib crane, various operations such as hoisting, retracting, turning and running are performed from a driver's cab 36 provided on the turning part 32. FIG. 3 is a plan view of the inside of the driver's cab seen from above. 41 is a right operation panel, 42 is a left operation panel, and these operation panels 41, 42 turn the jib 33 to the left by a notch operation of a master controller (not shown). It is for turning to the right or for running operation. Also, 43
Is a foot brake for a turning brake, 44 is a foot brake for a vibrator, and 45 is an instrument panel.

By the way, in the jib crane having such a structure, a wound motor is used as a drive source for various operations, and the jib may be subjected to a coasting operation to control turning or traveling, for example.

FIG. 4 shows a circuit configuration for controlling the jib crane. Reference numeral 20 is an AC power source, and 23 is a parallel circuit of a contactor 21 for turning right and a contactor 22 for turning left in the AC power source 20, and the primary side is In the connected wound motor, the secondary side of the wound motor 23 is grounded via a secondary resistor 29.

Further, 24 is a hydraulic brake for applying a braking force to the winding motor 23, and 25 is a hydraulic brake when energized through a foot brake switch contact 26 which is opened and closed by operating the foot brakes 43 and 44 shown in FIG. It is a hydraulic brake control device for controlling 24.

Further, 27 is a high-speed contactor for removing the secondary resistor 29 from the secondary side of the wound motor 23, and 28 is a low-speed contactor for varying the resistance value by grounding the tap derived from the secondary resistor 29. Is.

Here, the operation in the case of performing the coasting operation will be described. When the coasting notch is selected by the master controller (not shown), the contactor 2 for turning right is made.
Since 1 and the left turning contactor 22 are opened, the wire wound motor 23 is in a free run state, and the jib crane is naturally decelerated only by its mechanical loss. When the crane operator steps on the foot brake switch in the operator's cab, the hydraulic brake controller 25 operates and the hydraulic brake 24 operates due to the closing of the brake switch contact 26. As a result, the crane operator decelerates while visually confirming the speed of the crane through the instrument panel of the operator's cab, finally sets the main controller to the off notch, and brings the crane to a complete stop by the holding brake (not shown).

Further, when the crane is accelerated again during the coasting operation, if the main controller is returned to the notch for power running again, the contactor 21 for turning right or the contactor 22 for turning left is thrown in and the speed is further selected. By inserting the low speed contactor 28 or the high speed contactor 27 accordingly, the wound motor 23 is re-accelerated.

By the way, when using a squirrel-cage motor which can be controlled by an inverter device which is now commonly used as a drive source of a jig crane, it is technically attempted to control the jig crane by the above-mentioned coasting operation. It is difficult to implement because of various problems.

For example, when a coasting operation is selected, a contactor is inserted on the output side of the inverter device in order to free-run the cage motor, and this contactor is opened during coasting. If the contactor is closed to decelerate but then re-accelerate, the output frequency of the inverter device and the frequency of the internal induced voltage of the squirrel cage motor do not match, and even if they are the same, match the phases. I can't.

Therefore, a rush current flows when the contactor is closed, but the power supply capacity of the inverter device is much smaller than that of the AC power supply, and the inverter device becomes overcurrent and trips.

Next, if the squirrel-cage motor is decelerated only by the hydraulic brake of stepping without performing the coasting operation, when the hydraulic brake is applied, the squirrel-cage motor will be in a restrained state and a restraint current will flow. Since the power supply capacity of the inverter device is small, it still causes an overcurrent and trips. Even if the squirrel-cage motor is not constrained, the squirrel-cage motor is mechanically decelerated regardless of the output frequency of the inverter device, so the phase of the output voltage of the inverter device and the phase of the internal induced voltage of the squirrel-cage motor match. Instead, the inverter device becomes overcurrent and eventually trips.

As described above, it is difficult to realize the crane operation control device which involves the coasting operation using the inverter device. Therefore, as compared with the squirrel-cage motor, there is a problem that the secondary resistance control, which has a collector and a brush and requires much labor for maintenance, is used, and the control performance is inferior to that of the inverter device.

[0015]

As described above, in the conventional jib crane, the crane control device used for turning and traveling accompanied by the coasting operation is more troublesome in maintenance than the wound motor and the control performance is better than that of the inverter device. There was a problem that the secondary resistance control was inferior.

Further, even if the inverter device can be used for operations such as hoisting and traversing without coasting operation, since the winding type motor must be used for turning and traveling, the drive system of the entire crane cannot be unified. is the current situation. On the contrary, if an inverter device is used for turning and traveling, coasting operation cannot be performed, and there is a drawback that the operating characteristics of the operator are different from those of conventional cranes.

The present invention has been made in consideration of the above circumstances, and an object thereof is to provide a crane controller capable of realizing a coasting operation even if an inverter device and a squirrel cage motor are used. And

[0018]

In order to achieve the above object, the present invention constitutes a crane control device by the following means. The invention corresponding to claim 1 provides an inverter device for converting an output of an AC power supply to a predetermined voltage and frequency, and outputs the output of the inverter device to a squirrel-cage motor for speed control to control traveling or turning of a crane. In the crane control device, when the high speed command, the low speed command, or the stop command is given, an acceleration / deceleration limiting circuit that gives the inverter device a speed reference for changing the speed of the squirrel cage motor at a certain constant rate of change. ,
And a coasting deceleration limiting circuit which is connected in parallel to the acceleration / deceleration limiting circuit and which gives the inverter device a speed reference for decelerating the speed of the squirrel-cage motor at a deceleration equivalent to a free run during the coasting operation. It is a thing.

Therefore, in the crane control device having such a structure, when a coasting operation is requested, the speed reference is performed with the deceleration equivalent to the free run without disconnecting the squirrel cage motor from the inverter device. By gradually lowering, the speed of the squirrel-cage motor can be controlled as if decelerating by free run.

According to the second aspect of the invention, the output of the AC power supply is applied to an inverter device for converting it into a predetermined voltage and frequency, and the output of this inverter device is applied to a squirrel-cage motor to control the speed of the crane. Or, in a crane control device that controls turning, a high speed command, a low speed command,
Alternatively, when a stop command is given, an acceleration / deceleration limiting circuit that gives a speed reference for changing the speed of the squirrel-cage motor with a certain constant rate of change to the inverter device, and is connected in parallel to the acceleration / deceleration limiting circuit, A coasting deceleration limiting circuit that gives a speed reference to the inverter device to decelerate the speed of the squirrel cage motor at a deceleration equivalent to free run during a coasting operation, and is connected in parallel to the coasting deceleration limiting circuit, A braking deceleration limiting circuit that gives a speed reference for rapidly decelerating the squirrel cage motor to the inverter device when a brake command is given.

Therefore, in the crane control device having such a structure, when the brake command is given in addition to the same operation as described above, the squirrel cage motor is suddenly decelerated, and it is as if the mechanical brake is applied to decelerate. It works as if.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit configuration diagram showing an embodiment of a crane controller according to the present invention. In FIG. 1, reference numeral 1 is an AC power supply, and the output of the AC power supply 1 is given to a variable voltage variable frequency (VVVF) inverter device 2.
The output is supplied to the squirrel-cage motor 3.

On the other hand, P and N are control power source buses which form, for example, 15V and 0V lines, and a first variable resistor 12 for generating a high speed reference voltage and a low speed speed reference voltage are provided between these buses P and N. The generated second variable resistor 13 is connected in series.

The high-speed reference voltage generated by the first variable resistor 12 is input to the acceleration / deceleration limiting circuit 4 via the contact 7 closed by a high-speed command, and the low-speed reference voltage generated by the second variable resistor 13 is The acceleration / deceleration limiting circuit 4 is input through a contact 8 that is closed by a low speed command, and the voltage on the 0V line side is input to the acceleration / deceleration limiting circuit 4 through a contact 9 that is closed by a stop command.

Further, one end of a contact 10-1 which is closed by a coasting command is connected to the control power bus N on the 0V line side, and the other end is a contact 1 which is opened by a foot brake command.
It is connected to the input terminal of the coasting deceleration limiting circuit 5 via 1b.

Further, one end of a contact 10-2 which is closed by a coasting command is connected to the control power source bus N on the 0V line side, and the other end is connected to a contact 11a which is closed by a foot braking command and the deceleration limiting circuit 6 for the foot braking is connected. Connected to the input end.

The output terminals of the acceleration / deceleration limiting circuit 4, the coasting deceleration limiting circuit 5 and the foot brake deceleration limiting circuit 6 are commonly connected to the control terminal of the VVVF inverter device 2.

Here, a contact 7 closed by a high speed command, a contact 8 closed by a low speed command, a contact 9 closed by a stop command, and contacts 10-1, 1 closed by a coasting command.
Although not shown, 0-2 are contacts corresponding to the notches of the master controller, and no two or more commands are simultaneously established. Although not shown, the contact point 11a that closes and the contact point 11b that opens according to the foot brake command are contact points of a foot switch provided in the operator's cab.

Further, the acceleration / deceleration limiting circuit 4 makes the speed of the squirrel-cage motor 3 not stepwise at the time of normal operation, that is, when a high speed command, a low speed command or a stop command is given from a master controller (not shown). , With a certain rate of change.

Next, the operation of the crane controller constructed as described above will be described. For example, during high speed operation, the contact 7 is closed by a high speed command, so the high speed reference voltage set by the first variable resistor 12 is input to the acceleration / deceleration limiting circuit 4. As a result, the acceleration / deceleration limiting circuit 4 gradually accelerates from the stopped state, and the speed reference is VV so that the maximum speed is reached.
The speed of the cage motor 3 given to the VF inverter device 2 increases in synchronization with the rate of change set by the acceleration / deceleration limiting circuit 4.

The above operation is the same when the contact 8 is closed by the low speed command, and the low speed reference voltage set by the second variable resistor 13 is input to the acceleration / deceleration limiting circuit 4. In this case, if the low speed is set to 30% of the maximum speed, the squirrel cage motor 3 will increase in speed to the speed of 30% at the same ratio as in high speed.

When the contact 9 is closed by a stop command, the speed of the squirrel-cage motor 3 does not suddenly become zero, so that the speed is reduced by the deceleration set by the acceleration / deceleration limiting circuit 4 until then. It serves to reduce the speed reference that it was doing at a certain rate of change, which may or may not be the same as for acceleration. In this way, the squirrel cage motor 3 can be smoothly accelerated and decelerated.

Next, when a coasting operation is selected by a master controller (not shown), the contacts 10-1 and 10-2 are closed by a coasting command. At this time, the foot switch (not shown) is not stepped on, so the contact 11b opened by the foot brake command is closed, and the zero speed reference is VVVF via the coasting deceleration limit circuit 5.
It is given to the inverter device 2.

The coasting deceleration limiting circuit 5 includes:
The squirrel-cage motor 3 is temporarily separated from the VVVF inverter device 2 to be in a free-run state, and the deceleration when decelerated by only mechanical loss is set. By the operation of this circuit, the squirrel-cage motor 3 which has been operated at a certain speed up to now is decelerated at a deceleration equivalent to that of the free run.

It is assumed that the operator depresses the foot switch in such a state. At this time, the contact 11b is opened and the contact 11a is closed by the stepping brake command, so that the zero speed reference is given to the inverter device 2 through the stepping brake deceleration limiting circuit 6 via the contact 10-2 which is closed by the coasting command. .

The deceleration of the foot brake deceleration limiting circuit 6 is set so as to be the deceleration obtained by the conventional hydraulic brake. Therefore, when the operator depresses the foot switch, the squirrel cage motor 3 decelerates at the same deceleration as when the conventional hydraulic brake is applied.

Next, when the operator stops stepping on the foot switch, the contact 11a is opened and the contact 11b is closed by the foot brake command, so that the zero speed reference is again through the deceleration limiting circuit 5 for coasting to the VVVF inverter device 2 Entered in. Therefore, the squirrel cage motor 3, which has been rapidly decelerating at the deceleration set by the stepping brake deceleration limiting circuit 6 until now, is gently decelerated again by the deceleration set by the coasting deceleration limiting circuit 5. become.

When reacceleration is required, if high speed or low speed is selected by the master controller (not shown), the contacts 10-1 and 10-2 are opened by the coasting command, and the contacts by the high speed command or the low speed command. 7 or 8 is closed, and acceleration is performed at the rate set by the acceleration / deceleration limiting circuit 4 until the speed of the squirrel cage motor 3 reaches the high speed reference voltage or the low speed reference voltage.

As described above, in the embodiment of the present invention, during the coasting operation, the normal acceleration / deceleration limiting circuit is switched to the coasting deceleration limiting circuit 5 in which the same source speed as in the coasting operation is set to switch the VVVF inverter device. Since the operation of No. 2 is continued, the same deceleration performance and feeling of deceleration as the coasting operation can be obtained without disconnecting the squirrel-cage motor from the VVVF inverter device 2, and the squirrel-cage motor 3 is still connected to the VVVF inverter device 2. Since the operation of the VVVF inverter device 2 can be continued, the VVVF inverter device 2 does not become an overcurrent even when it is re-accelerated, and it can be realized only by the conventional combination of the wound motor 3 and the secondary resistor. You can get control and driving feeling.

When the foot switch is depressed, the coasting deceleration limiting circuit 5 is switched to the foot braking deceleration limiting circuit 6 in which the same deceleration as that of the hydraulic brake is set, so that the operation of the VVVF inverter device 2 is continued. , No need to install hydraulic brake. You can get the same deceleration performance and feeling of deceleration. Basically, the operation of the VVVF inverter device 2 is continued during that time, and since the squirrel cage motor 3 is not mechanically restrained, the VVVF inverter device 2 does not operate even if it is returned to the coasting operation or re-accelerated. It does not become a current, and the control and operation intervals that can be realized only by the conventional combination of the wound motor and the secondary resistor are obtained.

Furthermore, since the hydraulic brake can be eliminated, the weight of the crane can be reduced and the cost can be reduced. Recently, the crane itself has been used as is, but only the controller of the conventional winding motor and the crane that uses the secondary resistor has been replaced with a cage motor and an inverter device with good control performance, which is easy to maintain. There are many examples in which the next circuit is short-circuited and controlled by the inverter device. However, according to the present invention, since the conventional driving performance and driving feeling can be maintained, even if the control device is updated, the operator can accept the operation without feeling uncomfortable. You can expect an effect.

In the above embodiment, the control in the case of turning the jib by the coasting operation has been described, but in the case of running control, the same control as the above is performed without using the deceleration limit circuit 6 for the foot brake. It can be realized by doing.

[0043]

As described above, according to the present invention, even if an inverter device and a squirrel-cage motor are used, it is possible to obtain an operation performance equivalent to that of the coasting operation performed by the wire-wound motor and the secondary resistor. Therefore, it is possible to provide a crane control device capable of continuing the operation as a crane without the inverter device tripping due to overcurrent even when the vehicle is re-accelerated from the coasting operation.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of a crane controller according to the present invention.

FIG. 2 is a side view showing a schematic configuration of a jib crane.

FIG. 3 is a layout view of operating devices provided in a cab of the crane.

FIG. 4 is a circuit configuration diagram showing a conventional crane control device.

[Explanation of symbols]

1 ... AC power supply, 2 ... VVVF inverter device, 3 ...
... Squirrel cage motor, 4 ... Acceleration / deceleration limit circuit, 5 ... Coasting deceleration limit circuit, 6 ... Foot brake deceleration limit circuit, 7 ... Contact closed by high speed command, 8 ... Contact closed by low speed command , 9 ... contact closed by stop command, 10-1, 10-2 ... contact closed by coasting command, 11a ... contact closed by foot brake command, 11b ... contact opened by foot brake command,
12 ... A first variable resistor that generates a high speed reference voltage, 13 ... A second variable resistor that generates a low speed reference voltage.

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[Procedure amendment]

[Submission date] April 4, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction contents]

In the operation of such a jib crane, various operations such as hoisting, retracting, turning and running are performed from a driver's cab 36 provided on the turning part 32. FIG. 3 is a plan view of the inside of the driver's cab seen from above. 41 is a right operation panel, 42 is a left operation panel, and these operation panels 41, 42 turn the jib 33 to the left by a notch operation of a master controller (not shown). It is for turning to the right or for running operation. Also, 43
Is a foot switch for turning brake , 44 is a running brake
A foot switch, 45 is an instrument panel.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

FIG. 4 shows a circuit configuration for controlling the jib crane. Reference numeral 20 is an AC power source, and 23 is a parallel circuit of a contactor 21 for turning right and a contactor 22 for turning left in the AC power source 20, and the primary side is In the connected winding motor, the secondary side of the winding motor 23 is star-connected via the secondary resistor 29.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

Further, 27 is a high-speed contactor for removing the secondary resistor 29 from the secondary side of the wound motor 23, and 28 is a low-speed contactor for short-circuiting the tap derived from the secondary resistor 29 to vary the resistance value. Is.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

Here, the operation in the case of performing the coasting operation will be described. When the coasting notch is selected by the master controller (not shown), the contactor 2 for turning right is made.
Since 1 and the left turning contactor 22 are opened, the wire wound motor 23 is in a free run state, and the jib crane is naturally decelerated only by its mechanical loss. When the crane operator steps on the foot brake switch in the operator's cab, the hydraulic brake controller 25 operates and the hydraulic brake 24 operates due to the closing of the brake switch contact 26. As a result, the crane operator decelerates while visually confirming the speed of the crane , finally sets the main controller to an off notch, and brings the crane to a complete stop by a holding brake (not shown).

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction contents]

When the foot switch is depressed, the coasting deceleration limiting circuit 5 is switched to the foot braking deceleration limiting circuit 6 in which the same deceleration as that of the hydraulic brake is set to continue the operation of the VVVF inverter device 2. , slowdown equivalent deceleration performance and hydraulic brake can be obtained without providing a hydraulic brake. Basically, the operation of the VVVF inverter device 2 is continued during that time, and since the squirrel cage motor 3 is not mechanically restrained, the VVVF inverter device 2 does not operate even if it is returned to the coasting operation or re-accelerated. It does not become a current, and the control and driving feeling that can be realized only by the conventional combination of the wound motor and the secondary resistor can be obtained.

Claims (2)

[Claims] 1. A crane controller for controlling traveling or turning of a crane by applying an output of an AC power source to an inverter device for converting the output to a predetermined voltage and frequency, and applying the output of the inverter device to a squirrel-cage motor to control the speed. At, when a high speed command, a low speed command, or a stop command is given,
An acceleration / deceleration limiting circuit that gives a speed reference for changing the speed of the squirrel-cage motor at a certain rate of change to the inverter device, and the squirrel-cage motor connected in parallel to the acceleration / deceleration limiting circuit during coasting operation. And a coasting deceleration limiting circuit for giving the inverter device a speed reference for decelerating the vehicle speed at a deceleration equivalent to that of free run. 2. A crane controller for controlling traveling or turning of a crane by applying an output of an AC power source to an inverter device for converting the output to a predetermined voltage and frequency and applying the output of the inverter device to a squirrel-cage motor to control the speed. At, when a high speed command, a low speed command, or a stop command is given,
An acceleration / deceleration limiting circuit that gives a speed reference for changing the speed of the squirrel-cage motor at a certain rate of change to the inverter device, and the squirrel-cage motor connected in parallel to the acceleration / deceleration limiting circuit during coasting operation. Is connected to the coasting deceleration limiting circuit in parallel with the coasting deceleration limiting circuit for providing the inverter device with a speed reference for decelerating the vehicle speed at a deceleration equivalent to that of the free run, and when a brake command is given, the car A deceleration limiting circuit for a brake that gives a speed reference for rapidly decelerating a motor to the inverter device.