JPH1077105A - Method and device for controlling movement of pallet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a moving time of a cargo in the case of maximum torque unnecessary for a relatively light cargo, by detecting a load of a motor, setting a frequency to a first frequency obtaining maximum torque in the case of providing the cargo, and gradually increasing the first frequency when the load of the motor is less than a rated load. SOLUTION: In the case of moving a carriage 20 and a pallet 25 from a present position (L1, H1) to a destination (L2, H2), in a control device, based on an assigned job in an operating part, whether a cargo is provided or not is judged. In the case of providing the cargo, a first frequency obtaining maximum torque is set, in the case of not providing the cargo, maximum torque can not be obtained, but a second frequency higher than the first frequency is set. In the case of setting the first frequency, waiting till leading to rated operation, a drive current supplied to a motor M1, M2 is detected, in the case of detected current < rated current, the first frequency is increased by a fine frequency. In the case of detected current > rated current, also in the case of setting the second frequency, a power source of preset frequency is supplied to the destination.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier movement control device for supplying a variable frequency power supply current to a motor for moving a load.

[0002]

2. Description of the Related Art In automatic warehouses and factories, there is known a stacker crane for moving a load in both a traveling direction on a horizontal plane and a vertical direction with respect to a rack arranged in a matrix on a vertical plane. The stacker crane moves the bogie along the traveling rails laid on the floor, erects a mast on the bogie, raises and lowers the carrier with respect to the mast, and furthermore, moves the load on a vertical surface to take it in and out of the shelves. It is configured to be moved in a direction orthogonal to.
Further, as another device, a crane that mounts a traveling rail on a ceiling and hangs a load from the ceiling to move up and down is known.

Conventionally, for example, in a stacker crane, when a motor is inverter-controlled to move a load with respect to a load shelf in a short time, particularly when a load bed is moved up and down in a short time, the power supply frequency applied to the motor is set to The first frequency at which the maximum torque is obtained is set when the load is placed on the loading platform (loading status), and when the load is not loaded on the loading platform (no load status, empty loading status). Although the maximum torque cannot be obtained, the moving time in the "no load state" is shortened by setting the second frequency higher than the first frequency to increase the speed.

[0004]

However, in the above-mentioned conventional method, since the power supply frequency applied to the motor is set to the first frequency at which the maximum torque is obtained when the load is present, the load is relatively light. However, when the maximum torque is not required, there is a problem that the moving time is unnecessarily long.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, an object of the present invention is to provide a movement control apparatus for a carrier that can reduce the time required to move a load when the load is relatively light and does not require a maximum torque. And

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method of controlling the movement of a carrier for supplying a power supply current of a variable frequency to a motor for moving a load. And the frequency supplied to the motor is set to the first frequency at which the maximum torque is obtained when there is a load, and the second frequency is higher than the first frequency when there is no load. Set to
When the first frequency is set, it is determined whether the load of the motor is less than the rated load, and when the load is less than the rated load, the first frequency is gradually increased.

The present invention also provides a motor for moving a load, a power supply circuit for supplying a power supply current of a variable frequency to the motor, a motor load detecting means for detecting a load on the motor, The frequency supplied to the motor by the circuit is set to a first frequency at which the maximum torque is obtained when there is a load, and the frequency is set to a second frequency higher than the first frequency when there is no load. Control means for determining whether the load detected by the motor load detection means is less than a rated load when the frequency is set, and gradually increasing the first frequency when the load is less than the rated load. Features.

In this case, even if the detected load is less than the rated load, it is preferable to stop increasing the first frequency when the first frequency is higher than the second frequency.

Further, by detecting a drive current supplied from the power supply circuit to the motor, the load of the motor is detected, and when the current is less than the rated current, the first frequency is gradually increased. Is good.

In this case, even if the detected current is less than the rated current, the first frequency is equal to or higher than the second frequency.
It is preferable to stop the frequency increase.

Further, by detecting the power supplied from the power supply circuit to the motor, the load of the motor is detected, and when the power is less than the rated power, the first frequency is gradually increased. Good.

In this case, even if the detected power is less than the rated power, it is preferable to stop increasing the first frequency when the first frequency is higher than the second frequency.

Further, in a stacker crane in which a mast is erected on a bogie traveling on the floor and the luggage can be moved up and down on the mast, a motor for moving the luggage up and down along the mast, and a bogie arranged along the floor. It is preferable to apply the above-described control device to the control of the motor to run.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram illustrating a carrier movement control device of a stacker crane as one embodiment of a carrier traveling control method and device according to the present invention, and FIG.
3 is a block diagram showing a configuration of the control device, and FIG. 3 is a flowchart for explaining processing of the control device of FIG.

In FIG. 1, the load shelf (11) has a floor (12) and a ceiling (1).
3) and a plurality of columns (1
4) are connected by three connecting rods (15) in the horizontal direction, and the receiving frame (16) is provided at a predetermined interval in the vertical direction with respect to the support (14). Then, for such a shelf (11), the traveling rail (17) and the guide rail (1
8) are installed on a floor (12) and a ceiling (13), respectively, and a stacker crane (19) is provided so as to be movable in a horizontal direction along a traveling rail (17) and a guide rail (18).

The truck (2) constituting the stacker crane (19)
A mast (21) is erected in the center of (0). The wheels of the bogie (20) roll on the running rail (17), and the rollers provided at the upper end of the mast (21) are configured to roll along the guide rail (18). The traveling drive unit (24) is connected to the trolley (2
0) is provided with a motor (M1) capable of normal and reverse rotation, and by rotating this motor, the bogie (20) is moved to the traveling rail (17).
Move along the top. Further, the mast (21) is provided with a loading platform (25) and a lifting drive unit (31) for placing the load (34). Similarly, the motor (M2) that can rotate forward and reverse for the lifting drive (31)
The loading platform (25) is moved up and down along the mast (21) by rotating the motor. Although not shown, the loading platform (25) is provided with a loading / unloading drive unit for horizontally moving the loading / unloading (34) with respect to the loading rack (11).

The motor (M1) of the traveling drive unit (24),
Motor (M2) of lifting drive unit (31) (and unloading drive unit)
Is controlled by the control device (A) shown in detail in FIG. The motors (M1) and (M2) constituting the traveling drive unit (24) and the lift drive unit (31) respectively include the inverter circuit (5) from the commercial power supply (50).
A drive current having a variable frequency is supplied via (1) and (53) and the current detectors (52) and (54). Further, in order to detect the load on the motors (M1) and (M2), the drive currents (I) supplied to the motors (M1) and (M2) are detected by the current detectors (52) and (54). The control device (38) detects this detection current (I) as described later.
By controlling the inverter circuits (51) and (53) based on the above, the power supply frequency (f) supplied to each of the motors (M1) and (M2) is controlled.

The control device (A) is, as shown in FIG.
A height detector (35) for detecting the height (H) of the loading platform (25), and a bogie;
The travel position detector (3) that detects the position (L) in the travel direction of (20)
6) and an operation unit (37) for designating a target position of the carrier (25) for moving the cargo (34). In particular,
The height detector (35) can be constituted by, for example, a rotary encoder that detects the number of rotations of a driven sprocket provided on the mast (21), and the traveling position detector (36) is a wheel of the bogie (20). Can be constituted by a rotary encoder that detects the number of rotations. The operation unit (37) can be constituted by a push button provided on an operation panel provided on the load shelf (11). Also, the height detector (35) and the traveling position detector
(36) may be constituted by, for example, a linear encoder instead of the rotary encoder, and the operation unit (37) may be constituted by, for example, a remote personal computer instead of the push button provided on the operation panel.

Here, the cart (20) and the carrier (25) in FIG.
Is moved from the current position (L1, H1) to the destination position (L2, H2), there are a case of "with load" and a case of "without load". In addition, since the current (I) of the motors (M1) and (M2) increases as the load increases, the load (34) is relatively light when the current (I) is less than the rated current (I0), and the motor (M
It can be seen that 1) and (M2) have room.

Therefore, as shown in FIG. 3, the control device (38) first sets the "load present state" or the "no load state" based on the load unloading job specified by the operation unit (37) or the personal computer. (Step S
1) In the case of the "unloaded state", the first frequency (f1) at which the maximum torque is obtained is set (step S2). On the other hand, the maximum torque is not obtained in the "unloaded state", First
The second frequency (f2) is set higher than the frequency (f1) (step S3). When the first frequency (f1) is set, the operation waits until the rated operation is performed (step S3). When the rated operation is performed, the drive current (I) supplied to the motors (M1) and (M2) is detected. (Step S4) Then, it is determined whether or not the detected current (I) is less than the rated current (I0) (Step S5).

If I <I0, the process proceeds to step S6, where the first frequency (f1) is increased by the minute frequency (Δf), and then whether the first frequency (f1) is equal to the second frequency (f2) It is determined whether or not (step S7). And f1 =
If not f2, the flow returns to step S4 to gradually increase the first frequency (f1), while if f1 = f2, the flow goes to step S4.
Proceed to 8. Also, when I <I0 is not satisfied in step S5 and when the second frequency (f2) is set in step S3, the process proceeds to step S8. In this step S8, the set frequency (f2) is reached until the target position (L2, H2) is reached. ) Is supplied to the motors (M1) and (M2).

Therefore, according to the above embodiment, the load of the motors (M1) and (M2) is detected by the drive current (I), and when the drive current (I) <the rated current (I0), the first frequency is detected. Since (f1) is gradually increased, the moving time of the load can be reduced when the load is relatively light and the maximum torque is not required. In addition, even if the first frequency (f1) is gradually increased,
Since the control is performed so as not to exceed the frequency (f2), it is possible to prevent the required torque from being unable to be obtained.

In the above embodiment, the motors (M1), (M2)
Is detected by the drive current (I), but may be detected by electric power supplied to the motors (M1) and (M2) instead. In addition, although both the traveling speed of the truck (20) and the lifting speed of the carrier (25) are configured to be controlled, at least one of them, for example, only the lifting speed of the carrier (25) may be controlled. .

[0024]

As described above, according to the first and second aspects of the present invention, the frequency supplied to the motor is set to the first frequency at which the maximum torque is obtained when there is a load, and If no, the second frequency is set higher than the first frequency. If the first frequency is set, it is determined whether the load of the motor is less than the rated load. If the load is less than the rated load, the first frequency is gradually increased. Therefore, when the load is relatively light and the maximum torque is not required, the moving time of the load can be shortened.

According to the third aspect of the present invention, even if the detected load is less than the rated load, the increase of the first frequency is stopped when the first frequency is equal to or higher than the second frequency. Can be prevented from being lost.

According to the present invention, the load of the motor is detected by detecting the drive current supplied from the power supply circuit to the motor, and when the current is less than the rated current, the first frequency is gradually increased. Therefore, when the load is relatively light and the maximum torque is not required, the moving time of the load can be shortened.

According to the present invention, the increase in the first frequency is stopped when the first frequency is equal to or higher than the second frequency even if the detected current is less than the rated current. Can be prevented from being lost.

According to the present invention, the load of the motor is detected by detecting the power supplied to the motor, and the first frequency is gradually increased when the power is less than the rated power. In addition, when the load is relatively light and does not require the maximum torque, the load moving time can be reduced.

According to the seventh aspect of the present invention, since the motor for moving the loading platform up and down along the mast is controlled by the above-described method, it is possible to reduce the time required to lift and lower relatively light loads.

According to the eighth aspect of the present invention, since the motor for moving the bogie along the floor is controlled by the above-described method, the time for running a relatively light load along the floor can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing an embodiment of a traveling control device for a stacker crane according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of a control device in FIG. 1;

FIG. 3 is a flowchart illustrating a process of a control device in FIG. 2;

[Explanation of symbols]

 (11) Packing shelf (12) Floor (13) Ceiling (14) Post (15) Connecting rod (16) Receiving frame (17) Travel rail (18) Guide rail (19) Stacker crane (20) Bogie (21) Mast (24) Traveling drive unit (25) Loading platform (31) Lifting drive unit (34) Load (38) Control circuit (50) Commercial power supply (51) (53) Inverter circuit (52) (54) Current detector (M1) (M2) motor

Claims (9)

[Claims] 1. A method for controlling the movement of a carrier for supplying a power supply current having a variable frequency to a motor for moving a load, the method comprising detecting a load on the motor and supplying the load to the motor. The frequency is set to a first frequency at which a maximum torque is obtained when there is a load, and the frequency is set to a second frequency higher than the first frequency when there is no load, and the motor is set when the first frequency is set. Determining whether or not the load is less than a rated load, and gradually increasing the first frequency when the load is less than the rated load. 2. A motor for moving a load, a power supply circuit for supplying a power supply current of a variable frequency to the motor, a motor load detecting means for detecting a load on the motor, and the power supply circuit comprising: The frequency supplied to the motor
When the load is present, the first frequency is set to obtain the maximum torque, and when there is no load, the second frequency is set higher than the first frequency. When the first frequency is set, the motor load detecting means is set. And a control means for determining whether or not the load detected is smaller than the rated load and gradually increasing the first frequency when the load is smaller than the rated load. 3. The control means stops increasing the first frequency when the first frequency is equal to or higher than the second frequency, even if the load detected by the motor load detecting means is less than the rated load. 3. The movement control device for a cargo bed according to claim 2, wherein 4. The motor load detecting means detects a load of the motor by detecting a drive current supplied from the power supply circuit to the motor, and the control means detects the load of the motor by the motor load detecting means. It is determined whether or not the detected current is less than the rated current.
4. The movement control device for a carrier according to claim 2, wherein the frequency is gradually increased. 5. The control means according to claim 1, wherein said current detected by said motor load detection means is smaller than a rated current.
5. The movement controller according to claim 4, wherein the increase of the first frequency is stopped when the frequency is equal to or higher than the second frequency. 6. The motor load detecting means detects the load of the motor by detecting electric power supplied from the power supply circuit to the motor, and the control means detects the load of the motor by the motor load detecting means. 4. The movement control device for a bed carrier according to claim 2, wherein it is determined whether or not the supplied power is less than the rated power, and when the power is less than the rated power, the first frequency is gradually increased. 7. The control means stops increasing the first frequency when the first frequency is equal to or higher than the second frequency, even if the power detected by the motor load detecting means is less than the rated power. 7. The movement control device for a carrier according to claim 6, wherein: 8. The lift control device for a stacker crane, wherein a mast is erected on a truck moving on the floor, and the lift is provided on the mast. 8. The movement control device for a carrier according to claim 2, wherein the motor is a motor that moves the carrier up and down along a mast. 9. The movement control device for a stacker crane, wherein a mast is erected on a carriage moving on the floor, and the carrier is provided on the mast so as to be able to move up and down. 9. The movement control device for a luggage carrier according to claim 2, wherein the motor is a motor that moves the carriage along the floor.