JPH1110476A - Loader controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of abnormal operation of a loader caused by a deviation in core of a chuck when a workpiece is transferred from the loader to the chuck which is an external device without impairing the damage prevention effect at the time of collision of the loader. SOLUTION: A loader controller has load detection means 21 to 23 which detect load of motors 11 to 13 for driving loader and a loader protection means 17 which moves a loader 5 in the direction in which the predetermined detected load is eliminated when the predetermined load is detected by the means 21 to 23. In this configuration, a loader load detection stop means 18 is provided. This loader load detection stop means 18 stops the detection of load by the load detection means 21 to 23 when the loader stops at a workpiece transfer position where a workpiece is transferred from the loader 5 to a chuck which is an external device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loader control device having a protection function when a gantry loader or another loader collides with a machine tool or a workpiece.

[0002]

2. Description of the Related Art Conventionally, a machine tool such as a lathe, which has a loader such as a gantry loader, which is automatically operated, is often used. However, as the machine becomes more complicated with the progress of the machine tool and the loader, the number of interference points between the loader and the machine tool or the work increases, and the machine may be seriously damaged by collision. As a device to reduce damage in the event of such a collision, a device that protects the machine by monitoring the motor load of the loader and stopping the motor or generating a reverse thrust when the load exceeds the set value. Proposed. By generating a reverse thrust, the effect of preventing damage at the time of collision can be enhanced.

[0003]

However, if the motor load exceeds the set value and a reverse thrust is generated, the following erroneous motor load is detected while the loader is stopped, and unnecessary motor load is detected. There is a problem that a reverse thrust is generated and the machine is damaged. That is, as shown in FIG. 12, for example, when the work W is transferred from the chuck 52 of the loader 51 to the chuck 53 of the lathe main spindle, the chuck 53 on the main spindle side is moved while the centers of the two chucks 52 and 53 are not aligned. When gripping W, the loader 5
1, a load is applied vertically or horizontally, and in response to this load, a reverse thrust is generated in the motor of the loader 51,
The loader 51 and the lathe spindle will be damaged.

The present invention solves such a problem, and does not impair the effect of preventing damage in the event of a collision. Even when a workpiece is transferred from a loader to a chuck of an external device, abnormal operation of the loader caused by misalignment of the chuck. It is an object of the present invention to provide a loader control device which does not cause the load.

[0005]

A configuration of a loader control device according to a first embodiment of the present invention will be described with reference to FIG. 1 corresponding to an embodiment. The loader control device includes load detecting means (21 to 23) for detecting a load acting on the loader driving motors (11 to 13), and a load detecting means (21).
To 23), when a predetermined load is detected, the loader protection means (1) for moving the loader in a direction to eliminate the load.
7) and a loader load for stopping the load detection by the load detecting means (21 to 23) when the loader (2) stops at the work transfer position from the loader (2) to the chuck (19) of the external device (1). And a detection stopping means (18). According to this configuration, in the event of a collision, the loader protection means (17) causes the loader (2) to generate a thrust in the opposite direction, and causes the loader (2) to separate faster than the collision object.
Damage to the loader (2) and the collision object can be minimized. When the loader (2) stops at the position where the work (W) is transferred to the chuck (19) of the external device (1), the function of the load detection means (21 to 23) is reduced by the loader load detection stop means (18). Since the workpiece (W) is transferred from the loader (2) to the chuck (19) of the external device (1) with the misalignment, even if a load is applied to the loader (2), the loader (2) is stopped. 2) No thrust is generated in the reverse direction, and the external device (1) is generated due to the thrust.
Etc. can be prevented from being damaged.

A configuration of a loader control device according to a second embodiment of the present invention will be described with reference to FIG. 7 corresponding to the embodiment. The loader control device includes motors (11 to 1) for driving the loader.
Load detecting means (21-2) for detecting a load acting on 3)
3) a loader protection means (17) for moving the loader in a direction to eliminate the load when a predetermined load is detected by the load detection means (21 to 23); Loader stop detecting means (3) for detecting that the loader has stopped at a position to be delivered to the chuck
4), and in a state where the loader stop is detected by the loader stop detecting means (34), the load detecting means (21 to 2)
When the predetermined load is detected by 3), the movement of the loader by the loader protection means (17) is restricted. According to this configuration, when the loader stops at the work transfer position, the loader stop detection means (34) detects this, and at this time, even if the load detection means (21 to 23) detects a predetermined load, the loader protection means is detected. The movement of the loader due to (17) is restricted. Therefore, the work is transferred from the loader to the chuck of the external device with the center misaligned, so that even if a load is applied to the loader, a thrust in the reverse direction is not generated in the loader. Can be prevented from being damaged.

In each of the above configurations, as described with reference to FIGS. 1 and 10 corresponding to the embodiment, the loader (2)
When the difference between the center position of the chuck (14) for holding the work (W) and the center position of the chuck (19) of the external device (1) to which the work (W) is delivered exceeds a predetermined value,
Work (W) by chuck (19) of external device (1)
Re-positioning means (37) for stopping the gripping operation of the device and re-aligning the center position of the loader chuck (14) with the center position of the chuck (19) of the external device (1).
May be provided. In the case of this configuration, if there is a misalignment of a predetermined value or more between the chuck (14) of the loader (2) and the chuck (19) of the external device (1) at the work transfer position, both chucks (14, 19). The work (W) should be performed in the state
Is delivered, and it is possible to more reliably prevent an excessive force from being applied to the loader (2) and the external device (1).

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a perspective view showing an example of a loader to which the present invention is applied and a machine tool which is an external device. The machine tool 1 is a two-axis turret lathe, which includes two sets of a main shaft 2 and a turret 3 and has a work reversing device 4. The loader 5 is of a gantry type, and a lifting platform 9 is provided on a traveling platform 7 traveling along an installation rail 6 so as to be able to ascend and descend via a front and rear movable platform 8, and a loader head 10 is provided at a lower end of the lifting rod 9. It is. The loader head 10 is provided with two chucks 14 (FIG. 5) in a forward position facing the main shaft 2 and a downward position.
The position of 4 is interchangeable. These traveling platforms 7
1 (movement in the X-axis direction), movement in the front-rear direction (movement in the Z-axis direction) of the front-rear movable table 8, and movement of the lifting rod 9 (movement in the Y-axis direction) are performed by driving the servomotors 11 to 13 in FIG. Done in

FIG. 6 is a block diagram showing a conceptual configuration of the loader control device. The loader control device 15 controls the operation of the loader 5. The loader control device 15 includes a CPU, a memory, and the like, stores a loader program 16, stores loader protection means 17, load current detectors 21 to 23 for each axis, a loader And a load detection stopping means 18 for controlling each axis of the loader 5 according to the loader program 16.
13 is controlled.

FIG. 1 is a block diagram showing a conceptual configuration of a loader protection function portion in the loader control device 15. An X-axis load current detector 21 including an ammeter, a Y-axis load current detector 22, and a Z-axis load current detector 23 are provided in a power supply circuit of each axis servo motor 11 to 13 of the loader 5, respectively. A loader protection means 17 is provided for monitoring and protecting a collision from the current values of these detectors 21 to 23 for protection.
The detection value of each of the load current detectors 21 to 23 is converted into a digital value by a data input unit of the loader protection means 17 or an A / D converter (not shown) provided outside and used for the subsequent processing. .

The loader protection means 17 simultaneously monitors the motor loads of the three axes of X, Y, and Z axes. The X axis monitoring means 24 and the Y axis monitoring means 2 are controlled by software or the like.
5, and Z-axis monitoring means 26. Since the respective axis monitoring units 24 to 26 have the same configuration, only the Z axis monitoring unit 26 will be described, and the description of the other units 24 and 25 will be omitted.

The Z-axis monitoring means 26 includes sampling filter means 27, acceleration / deceleration load correction means 28, overload detection means 29, and reverse thrust command means 30. The sampling filter means 27 includes a Z-axis load current detector 23.
Means for calculating an average value of a plurality of sampling values in the past and outputting as input data. By this filtering, the influence of erroneous detection data due to noise or the like is averaged, and erroneous detection can be eliminated.

The acceleration / deceleration load correction means 28 is a means for correcting and calculating a current value b obtained by subtracting the current values of the acceleration load and the deceleration load during acceleration / deceleration from the current value a obtained by the sampling filter means 27. That is, the current value a shown in FIG. 2A is corrected to the current value b shown in FIG. Thus, proper load monitoring can be performed during the entire movement period T0 including the acceleration period T1 and the deceleration period T2. The acceleration load and the deceleration load can be known in advance from the motor characteristics and the inertia of the machine.

The overload detecting means 29 is a means for monitoring the current value b corrected as described above and outputting a collision signal c when the current value b exceeds the set value A. The current value b may be compared with the set value A by performing an appropriate statistical operation. The reverse thrust command means 30 responds to the collision detection signal c,
This is a means for supplying a current to the Z-axis servomotor 13 so that a thrust in the reverse direction is generated in the loader head 10 by a predetermined distance. The set distance may be set by the current supply time and the applied voltage, or may be set by the power consumption.

The loader load detecting and stopping means 18 transfers the work W (X) from the chuck 14 of the loader 5 to the spindle chuck 19 of the machine tool 1 as an external device as shown in FIG.
When the loader 5 stops at (1, Y1, Z1), the detection of the load current by each axis load current detector 21 to 23 is stopped. The stop of the loader 5 at the work transfer position (X1, Y1, Z1) is performed by the servomotors 11 to 11 of the respective axes of the loader 5.
13 by reading the outputs of the encoders 31-33.

The operation of the above configuration will be described. In a normal operation state, one movement of the loader head 10 back and forth causes Z
The load current of the shaft servomotor 13 has a curve shown in FIG. 2A, which is corrected as shown in FIG. The corrected load current value b is constantly monitored by the overload detecting means 29. If a collision occurs during this time, the load current value b rapidly increases, for example, as indicated by a broken line b ′ in FIG. The overload detecting means 29 detects this collision as a load current value b
Exceeds the set value A, the collision detection signal c
Is output. In response to the collision detection signal c, the reverse thrust command means 30 supplies a current to the Z-axis servomotor 13 so that a reverse thrust is generated in the loader head 10 by a predetermined distance.

For example, if a collision occurs at time t1 while the Z-axis servo motor 13 is rotating at the motor speed U1 shown in FIG. 3, the motor 13 is driven until time t2 when the motor speed U becomes zero. Overrun only for the period S1,
Thereafter, current is supplied so as to rotate in the reverse direction for periods S2 and S3, and the motor is pulled back. The moving distance in each of the periods S1 to S3 is obtained from the area of the hatched portion.

In the above monitoring and control, X
The load monitoring and the reverse thrust command for the Z axis are independently performed. For example, if collision detection is performed for two axes, the Z axis and the X axis, the reverse thrust is applied to both the X axis and the Z axis. give. When the collision detection signal c is received for any of the axes, the entire machine is stopped except for the driving of the reverse thrust.

When the loader 5 stops at the position (X1, Y1, Z1) for transferring the work W from the loader 5 to the spindle chuck 19 of the machine tool 1 as indicated by a chain line in FIG. The load detection by the load current detectors 21 to 23 of each axis is stopped by the load detection stopping means 18. As a result, at the time of workpiece transfer, the center position of the chuck 14 of the loader 5 and the spindle chuck 1 of the machine tool 1
9 is slightly deviated from the center position of the load 9, and in a state where the workpiece W is gripped by the spindle chuck 19, an overload exceeding the set value A set in the overload detecting means 29 is applied to the loader 5. In addition, the loader protection means 17 does not generate a thrust in the reverse direction on the loader 5, so that the loader 5 and the spindle chuck 19 can be prevented from being damaged due to the generation of the thrust in the reverse direction.

According to the loader control device 15, when the loader 5 collides, it not only stops but also instantaneously generates a thrust in the reverse direction by a predetermined distance, so that the loader 5 separates from the colliding object earlier and is damaged. Can be minimized. Further, when the workpiece W is transferred from the loader 5 to the spindle chuck 19 of the machine tool 1 which is an external device, even if there is a misalignment between the chuck 14 of the loader 5 and the spindle chuck 19 of the machine tool 1, Since the function of the loader protection means 17 is stopped when the work is delivered, it is possible to reliably prevent the load 5 and the spindle chuck 19 from being damaged by generating an unnecessary reverse thrust on the load 5 when the work is delivered.

An embodiment corresponding to the loader control device according to claim 2 of the present invention will be described with reference to FIGS.
FIG. 8 is a block diagram showing a conceptual configuration of the loader control device. In this embodiment, a loader stop detection unit 34 is provided in place of the loader load detection stop unit 18 in the loader control device 15 of the previous embodiment.

FIG. 7 is a block diagram showing a conceptual configuration of a loader protection function in the loader control device of this embodiment. The loader stop detecting means 34 is a work transfer position (X1, Y2, Z3) for transferring the work W gripped by the chuck 14 of the loader 5 to the spindle chuck 19 of the machine tool 1.
Is a means for detecting that the loader 5 has stopped. The detection of the loader stop is performed by the encoders 31 to 33 provided on the respective axis servomotors 11 to 13 of the loader 5 as in the case of the loader load detection stop means 18 in the previous embodiment.
This is done by reading the output of In addition, the axis monitoring means 24 to 26 of the loader protection means 17 supplies the collision detection signal c output from the overload detection means 29 in a state where the loader stop is detected by the loader stop detection means 34.
Is provided for preventing the input of the reverse direction thrust to the reverse thrust commanding means 30. Thereby, even if the overload detecting means 29 detects a load exceeding the set value A in the loader stop detection state, the movement of the loader 5 by the loader protecting means 17 is restricted. Other configurations are the same as those of the previous embodiment.

Also in the case of the loader control device 15, the loader protection means 17 is stopped when the work is transferred from the chuck 14 of the loader 5 to the spindle chuck 19 of the machine tool 1, so that unnecessary reverse thrust is applied to the load 5. This can reliably prevent the loader 5 and the spindle chuck 19 from being damaged. If the loader 5 collides during other operations,
It is similar to the previous embodiment that the loader 5 can be separated earlier than the collision object and the damage of the loader 5 can be minimized.

A further embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a block diagram showing a conceptual configuration of the loader control device. In this embodiment,
The loader control device 15 of the embodiment shown in FIGS. 1 to 6
In addition, the center deviation monitoring means 36 and the repositioning instruction means 37
Is added.

FIG. 10 is a block diagram showing a conceptual configuration of a relationship between the center deviation monitoring means 36 and the repositioning instruction means 37 and the control device 38 of the machine tool 1 in the loader control device of this embodiment. Machine tool controller 38
Is a computer-based control device for controlling the entire machine tool 1, comprising a programmable controller and an NC device, an arithmetic control unit 43 for analyzing and executing a machining program 39, and each axis servo of the machine tool 1. And a servo driver 40 for driving the motor.

The center shift monitoring means 36 in the loader control device 15 determines that the loader 5 has a work transfer position (X1, Y
1, Z1), the chuck 14 of the loader 5
And a center position of the spindle chuck 19 of the machine tool 1 to which the workpiece W is transferred from the loader 5. The X-axis monitoring unit 41 and the Y-axis monitoring unit 42 of the center deviation monitoring unit 36 are configured by software or the like. Since the two-axis monitoring units 41 and 42 have the same configuration, only the Y-axis monitoring unit 42 will be described, and the description of the other units 41 will be omitted.

The Y axis monitoring means 42 is
4 and a gripping operation stop instructing means 45. The center shift detecting means 44 detects how much the center position of the loader chuck 14 at the workpiece transfer position is shifted from the center position of the spindle chuck 19 in the Y-axis direction, and the amount of the shift is a predetermined value B set in advance. This is a means for outputting a center shift detection signal d when the difference is exceeded. The center shift amount is determined by reading the output of the encoder 32 provided on the corresponding Y-axis servo motor 12 of the loader 5. The gripping operation stop instructing unit 45 responds to the center deviation detection signal d output from the center deviation detecting unit 44 and
The work W by the spindle chuck 19 is provided to the arithmetic control unit 43 of FIG.
This is a means for giving a command to stop the gripping operation of.

The re-positioning instructing means 37 in the loader control device 15 includes the axis monitoring means 4 of the center deviation monitoring means 36.
This is a means for giving a command to the loader 5 to re-align the center position of the chuck 14 to the center position of the spindle chuck 19 in response to the center deviation detection signal d output from the first and second units 42.

In the case of the loader control device 15, if there is a misalignment of a predetermined value or more between the chuck 14 of the loader 5 and the spindle chuck 19 of the machine tool 1 at the work transfer position, the two chucks 14, 19 are moved. Since the alignment is performed again, the work W is delivered in a state where the alignment is correctly performed, and it is possible to prevent an excessive force from being applied to the loader 5 and the spindle chuck 19.

In this embodiment, the case where the center deviation monitoring means 36 and the repositioning instruction means 37 are added to the loader control device 15 in the embodiment of FIGS. 1 to 6 is shown. A similar function can be provided by adding to the loader control device 15 in the embodiment.

In the embodiment shown in FIG. 10, the function and configuration of the loader protection means 17 in the embodiment described with reference to FIG. 1 are used as they are. In the embodiment shown in FIG. 10, the following copying control means 46 shown in FIG. May be used. This copying control means 46
X, Y, and Z are provided for each axis.
13 is detected by a load current or the like, and the corresponding axis of the loader 5 is moved in a direction to keep the load constant. When the center of the loader chuck 14 is largely displaced from the center of the spindle chuck 19, the copying control means 46 has a load equal to or larger than the set value. In this case, the load is returned to the set value, that is, the loader chuck 14
Is moved toward the center of the spindle chuck 19. Since the copying control is performed, the movement of the loader 5 is controlled so that the load does not become lower than the set value. Accordingly, even when the center of the loader chuck 14 is deviated from the center of the spindle chuck 19, the misalignment can be corrected in real time. This copying control can also be applied to the embodiments shown in FIGS.

In each of the above embodiments, the load current is converted to a digital value and the comparison for collision detection is performed. However, the collision detection is performed by comparing the analog current with the set value while keeping the analog value. Is also good. Further, the above embodiments have been described with respect to the case where the present invention is applied to a gantry loader, but the present invention can be applied to control of various types of loaders.

[0033]

According to the first aspect of the present invention, there is provided a loader control device for detecting a load acting on a motor for driving a loader, and a load when a predetermined load is detected by the load detection device. Loader protection means for moving the loader in a direction to eliminate the load, and loader load detection stop means for stopping the load detection by the load detection means when the loader stops at the work transfer position from the loader to the chuck of the external device. In addition, even when the work is transferred from the loader to the chuck of the external device, an abnormal operation of the loader due to the misalignment of the chuck can be avoided without impairing the damage prevention effect at the time of collision. According to a second aspect of the present invention, there is provided a loader control device for detecting a load acting on a motor for driving a loader, and canceling the load when a predetermined load is detected by the load detection device. Loader protection means for moving the loader in the direction, and loader stop detection means for detecting that the loader has stopped at a position where the work held by the loader is transferred to the chuck of the external device. When the predetermined load is detected by the load detection means in the state where the load is detected, the movement of the loader by the loader protection means is restricted. Therefore, even in this configuration, the effect of preventing damage at the time of collision is impaired. It is possible to avoid abnormal operation of the loader caused by misalignment of the chuck even when transferring the work from the loader to the chuck of the external device. Kill. In each of the loader control devices described above, when the difference between the center position of the chuck for gripping the work of the loader and the center position of the chuck of the external device to which the work is delivered exceeds a predetermined value, the operation of gripping the work by the chuck of the external device. Is stopped and the re-alignment means for re-aligning the center position of the loader chuck with the center position of the chuck of the external device is provided. Since the adjustment is performed again, it is possible to more reliably prevent an excessive force from being applied to the loader and the external device.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a conceptual configuration of a main part of a loader control device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a load current detection value and a collision occurrence state by the loader control device.

FIG. 3 is an explanatory diagram of motor speed in a reverse thrust action state at the time of loader collision.

FIG. 4 is a perspective view showing an example of a loader and a machine tool to which the loader control device is applied.

FIG. 5 is an explanatory diagram showing a state where a work is transferred from a loader to a machine tool.

FIG. 6 is a block diagram showing a conceptual configuration of the loader control device.

FIG. 7 is a block diagram showing a conceptual configuration of a main part of a loader control device according to another embodiment of the present invention.

FIG. 8 is a block diagram showing a conceptual configuration of the loader control device.

FIG. 9 is a block diagram showing a conceptual configuration of a loader control device according to still another embodiment of the present invention.

FIG. 10 is a block diagram showing a conceptual configuration of a relationship between a main part of the loader control device and a machine tool control device.

FIG. 11 is a block diagram showing a conceptual configuration of a relation between a main part of a loader control device and a machine tool control device according to still another embodiment of the present invention.

FIG. 12 is an explanatory diagram showing a problem of the conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Machine tool (external device) 29 ... Overload detection means 5 ... Loader 34 ... Loader stop detection means 11-13 ... Each axis servo motor 35 ... Gate means 17 ... Loader protection means 36 ... Center deviation monitoring means 18 ... Loader load Detection stop means 37 ... Repositioning command means 19 ... Spindle chuck 45 ... Grip operation stop command means 21-23 ... Each axis load current detector

Claims (3)

[Claims] A load detecting means for detecting a load acting on a motor for driving the loader; and a loader protecting means for moving the loader in a direction to eliminate the load when a predetermined load is detected by the load detecting means. And a loader load detecting and stopping means for stopping the load detection by the load detecting means when the loader stops at a work transfer position from the loader to the chuck of the external device. 2. A load detecting means for detecting a load acting on a motor for driving the loader, and a loader protecting means for moving the loader in a direction to eliminate the load when a predetermined load is detected by the load detecting means. A loader stop detecting unit that detects that the loader has stopped at a position where the work held by the loader is transferred to the chuck of the external device,
A loader control device for restricting movement of a loader by a loader protection unit when a predetermined load is detected by a load detection unit in a state where a loader stop is detected by a loader stop detection unit. 3. When the difference between the center position of the chuck for gripping the work of the loader and the center position of the chuck of the external device to which the work is delivered exceeds a predetermined value, the operation of gripping the work by the chuck of the external device is stopped. 3. The loader control device according to claim 1, further comprising repositioning means for repositioning the center position of the loader chuck and the center position of the chuck of the external device.