JP2002066858A - Positioning method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To take necessary measures according to the condition of load applied to a drive means, before the load becomes excessive. SOLUTION: An operation command is transmitted from a controller 14 to an inverter 13 according to the output of a pulse encoder 12 which detects the position of a movable portion 1, so that the movable portion 1 is moved by operation of a motor 11. The condition of outputs from the inverter 13 to the motor 11 is inputted also to the controller 14, which in turn monitors the condition of load applied to the motor 11. If the load exceeds a preset value, the operation command transmitted from the controller 14 to the inverter 13 is adjusted so that the load decreases. During operation of the motor 11 at accelerated or decelerated rate, the time of acceleration or deceleration is extended; during operation of the motor 11 at constant speed, its operating speed is reduced. The operation of the motor 11 is thus continued.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning method applied to, for example, positioning of a movable portion of a machine tool, and a positioning device.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 3, a movable part of a machine tool, for example, a back gauge 21 of a shearing machine, moves forward and backward by rotation of a pair of parallel ball screws 22, 22. Ball screw 22, 22
Is rotated by the operation of the motor 23, and the position of the back gauge 21 is detected by the pulse encoder 24. Any suitable rotation mechanism can be used for each part. For example, the main shaft 25 rotated by a motor 23 and the ball screws 22 are driven and connected via a bevel gear 26 so that the rotation of the main shaft 25 is controlled. The pulse encoder 24 detects the rotational position of the spindle 25 while transmitting the rotation to the ball screws 22, 22.
The position of the back gauge 21 can be detected through the rotation position of the ball screw 5 and the ball screws 22, 22.

[0003] Such a back gauge 21 is controlled by a controller (PLC) 2 according to the output of a pulse encoder 24.
8 transmits an operation command to the inverter 29 and the inverter 2
The back gauge 21 is moved and positioned by the operation of the motor 23 based on the control of No. 9. That is, when a pulse is input from the pulse encoder 24 to the controller (PLC) 28 in accordance with the rotation of the main shaft 25, the controller (PLC) 28 converts the frequency, current, and voltage necessary for operating the motor 23 into an inverter 29. Output from the inverter 23 to the motor 23.
9 outputs a frequency command, an acceleration / deceleration time command, and a run / stop command. If the load on the motor 23 becomes excessive enough to cause damage to the machine, an alarm is input from the inverter 29 to the controller (PLC) 28. It is supposed to be.

[0004] Such a positioning method is widely used in various machine tools as an inexpensive method suitable for positioning a movable portion such as the back gauge 21 which does not need to be moved at such a high speed. .

[0005]

However, in such a conventional apparatus, even if the load gradually increases due to a decrease in the lubricating oil grease of the ball screws 22 and 22, for example, the pulse Since the encoder 24 cannot detect the change, the controller (PLC) 28 cannot recognize the abnormality until the load becomes heavy and the inverter 29 generates an overload alarm. Therefore, in the worst case, there is a problem that mechanical parts such as the ball screws 22 may be damaged before an alarm from the inverter 29 occurs.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned problems of the prior art, and to take necessary precautions before the load becomes excessive according to the load on the drive means. It is an object of the present invention to provide a method and an apparatus therefor.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and the invention according to claim 1 is to control the drive means from the control means in accordance with the output of the detection means for detecting the position of the object. In a positioning method for transmitting an operation command and moving and positioning an object by driving a driving unit, a step of monitoring the state of a load applied to the driving unit by the control unit, and a step of monitoring the load by a load exceeding a predetermined value. The control means adjusts an operation command to the drive means so that the load is reduced, and continues the operation of the drive means.

According to a second aspect of the present invention, in the first aspect of the present invention, the adjustment of the operation command is a positioning method for extending a predetermined acceleration / deceleration time during acceleration / deceleration operation of the drive means.

According to a third aspect of the present invention, in the first aspect of the invention, the adjustment of the operation command is a positioning method for reducing a predetermined operation speed during a constant speed operation of the driving means.

According to a fourth aspect of the present invention, an operation command is transmitted from the control means to the drive control unit of the motor in response to the output of the detection means for detecting the position of the object, and the operation of the motor is controlled based on the control of the drive control unit. In a positioning method for moving and positioning an object, a state of a load applied to a motor is monitored by a control unit by inputting an output state from the drive control unit to the motor to the control unit. When the value exceeds a predetermined value, the control unit adjusts an operation command to the drive control unit so that the load is reduced, and continues the operation of the motor. .

According to a fifth aspect of the present invention, an operation command is transmitted from a controller to an inverter in accordance with an output of a pulse encoder for detecting a position of a movable portion of a machine tool, and the movable portion is moved by an operation of a motor based on the control of the inverter. In the positioning method of performing positioning by inputting the output status from the inverter to the motor, the controller also monitors the status of the load applied to the motor by inputting the output status to the controller. When it exceeds, the controller adjusts the operation command to the inverter so that the load becomes small,
Continuing the operation of the motor.

According to a sixth aspect of the present invention, in the invention of the fourth or fifth aspect, the adjustment of the operation command is a positioning method for extending a predetermined acceleration / deceleration time during the acceleration / deceleration operation of the motor. .

According to a seventh aspect of the present invention, in the fourth or fifth aspect of the invention, the adjustment of the operation command is a positioning method for reducing a predetermined operation speed during a constant speed operation of the motor. .

According to an eighth aspect of the present invention, there is provided a positioning apparatus for transmitting an operation command from a control unit to a driving unit in accordance with an output of a detection unit for detecting a position of an object, and moving and positioning the object by operation of the driving unit. A means for monitoring the status of the load applied to the driving means, and when the load exceeds a predetermined value, adjusts an operation command from the control means to the driving means such that the load is reduced. And a means for continuing the operation of the driving means.

According to a ninth aspect of the present invention, in the invention according to the eighth aspect, the operation command is adjusted by extending a predetermined acceleration / deceleration time during acceleration / deceleration operation of the drive means.

According to a tenth aspect of the present invention, in the invention according to the eighth aspect, the adjustment of the operation command is a positioning device that reduces a predetermined operation speed when the driving means is operating at a constant speed.

According to an eleventh aspect of the present invention, an operation command is transmitted from the control means to the drive control unit of the motor in accordance with the output of the detection means for detecting the position of the object, and the operation of the motor is controlled based on the control of the drive control unit. In a positioning device that moves and positions an object, by inputting an output status from the drive control unit to the motor to the control unit, a unit that monitors a status of a load applied to the motor, Means for adjusting an operation command from the control means to the drive control unit so that the load is reduced when the value exceeds a predetermined value, and means for continuing the operation of the motor. .

According to a twelfth aspect of the present invention, an operation command is transmitted from a controller to an inverter in accordance with an output of a pulse encoder for detecting a position of a movable part of a machine tool, and the movable part is driven by a motor based on the control of the inverter. In a positioning device for moving and positioning, by inputting the output status from the inverter to the motor also to the controller, means for monitoring the status of the load applied to the motor by the controller, wherein the load is a predetermined value And a means for adjusting the operation command from the controller to the inverter so that the load is reduced when the load exceeds the value, so as to continue the operation of the motor.

According to a thirteenth aspect of the present invention, in the invention of the eleventh or twelfth aspect, the adjustment of the operation command is performed by a positioning device for extending a predetermined acceleration / deceleration time during the acceleration / deceleration operation of the motor. is there.

According to a fourteenth aspect of the present invention, in the eleventh or twelfth aspect, the adjustment of the operation command is performed by a positioning device that reduces a predetermined operation speed when the motor is operated at a constant speed. is there.

[0021]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing an embodiment of a positioning device according to the present invention. This positioning device 10 is applied to a back gauge 1 of a shearing machine. That is, the back gauge 1 is
Is rotated by rotation of a pair of parallel ball screws 4 transmitted through, for example, the bevel gear 3. Therefore, the positioning device 10
The motor includes a motor 11 for rotating the spindle 2 and a pulse encoder 12 for detecting a rotational position of the spindle. When the motor 11 rotates the spindle 2, the ball screws 4 and 4 are rotated via the bevel gear 3 and a back gauge 1 is advanced and retracted, while the pulse encoder 12 detects the rotational position of the main shaft 2, thereby detecting the position of the back gauge 1 via the rotational positions of the ball screws 4.

The positioning device 10 also includes an inverter 13 as a drive control unit of the motor 11 and a controller (PLC) for transmitting an operation command of the motor 11 to the inverter 13.
And a detection output of the pulse encoder 12 is input to the controller (PLC) 14.

The controller (PLC) 14 is configured to be able to communicate with the inverter 13, and outputs the frequency, current and voltage required for operating the motor 11 from the inverter 13 to the motor 11. An operation control unit 15 for outputting a frequency command, an acceleration / deceleration time command, and a run / stop command to the motor 11
And a monitoring unit 16 to which the output frequency, the output current, and the output voltage are input from the inverter 13 in order to monitor the rotation speed, the output current, and the output voltage associated with the operation.

That is, the monitoring unit 16 monitors the status of the load applied to the motor 11 by inputting the output status from the inverter 13 to the motor 11, and the operation control unit 15 When the load on the machine exceeds a preset value,
The operation of the motor 11 is continued by adjusting the operation command to the inverter 13 so as to reduce the load.

When the load exceeds the set value during the acceleration / deceleration operation of the motor 11, the operation control unit 15 adjusts the operation command by extending the predetermined acceleration / deceleration time. The operation is continued while reducing the load.

The operation control unit 15 includes the motor 1
If the load exceeds the set value during the constant speed operation 1, the operation command is adjusted by reducing the predetermined operation speed, thereby continuing the operation while reducing the load on the motor 11. It is made to let.

Next, the operation of the above embodiment will be described.
This will be described with reference to the flowchart shown in FIG.

First, a frequency (initial value f ₀ ) and an acceleration / deceleration time (initial value t ₀ ) to be commanded from the controller (PLC) 14 to the inverter 13 in order to operate the motor 11 are set. when 11 was allowed to operation, to measure a current value and a voltage value supplied to the motor 11 (normal current value i _n and the normal voltage value v _n) in the normal state. Then, the normal current value _{i n} and the normal voltage value _{v n}
In contrast, when the current value and the voltage value actually flowing to the motor 11 fluctuate to what extent, the current value and the voltage value (abnormal Current value i _u and abnormal voltage value v
_u ) is set in the controller (PLC) 14 as a parameter for each of the acceleration / deceleration operation and the constant speed operation (step S1).

Next, the controller (PLC) 14
Frequency command (initial value f₀) And acceleration / deceleration time command (initial
Value t₀) Is output to the inverter.
Step S2). In response to this, the inverter 13 sets the motor 11
And the position of the back gauge 1 moved by it
Position is detected by the pulse encoder 12, and the pulse is
Controller (PLC) 14. controller
(PLC) 14 is input from the pulse encoder 12
Based on the pulse, a predetermined frequency command (initial value f ₀)
And acceleration / deceleration time command (initial value t₀)
Output to the inverter 13 and the back gauge 1
Is moved toward a predetermined position.

During the operation of such a system, the output frequency, output current and output voltage of the inverter 13 which are linked to the rotation speed, output current and output voltage of the motor 11 are input from the inverter 13 to the controller (PLC) 14. Continue (step S3).

In response to this, the controller (PLC) 14 monitors the status of the load applied to the motor 11 by the monitoring unit 16 (step S4). That is, the output frequency f input from the inverter 13 becomes equal to the command frequency f0.
Is not equal to, the motor 11 is in acceleration / deceleration operation,
When they are equal, the motor 11 is operating at a constant speed.

When the motor 11 is in the acceleration / deceleration operation, the output current i and the output voltage v input from the inverter 13 are equal to the abnormal current value i _u and the abnormal voltage value v _u during the acceleration / deceleration operation set in advance as parameters. Beyond the (step S5), and the controller (PLC) 14 is, increase the deceleration time t that is issuing to the inverter _{13 (t = t 0 + t} U) that is, extending the acceleration and deceleration time of the motor 11 (step At the same time as S6), a warning display of acceleration / deceleration abnormality is displayed (step S7).

On the other hand, when the motor 11 is operating at a constant speed, the output current i and the output voltage v input from the inverter 13 are equal to the abnormal current value i _u and the abnormal voltage value at the time of the constant speed operation set as parameters in advance. If v _u is exceeded (step S8), the controller (PLC) 14
By reducing the frequency f commanded to the inverter 13 (f = f ₀ −f _U ), the operation speed of the motor 11 is reduced (step S9), and a warning display of abnormality at constant speed is displayed (step S10). ).

When the positioning is completed (step S11), the operation command from the controller (PLC) 14 to the inverter 13 is stopped (step S11).
12).

Thus, when the motor 11 is overloaded, the overload of the motor 11 is apparently reduced by reducing the overload and changing the operation state so as to substantially eliminate the overload. The operation is continued without any trouble.

If, for example, a value at which the feeder belt of the shearing machine idles is set as the threshold value for judging the overload of the motor, it is possible to detect that when the feeder belt starts idling. it can.

If a threshold is set for each of a plurality of overload stages as required, various overload stages can be detected.

Further, in the above embodiment, the monitoring unit of the controller (PLC) is configured to monitor the status of the load applied to the motor based on the output current and the output voltage input from the inverter. Instead, for example, it is possible to estimate a change in the situation on the load side based on the output frequency of the inverter and the number of revolutions of the motor.

Further, in the above embodiment, the present invention is applied to the positioning of the back gauge of the shearing machine. However, the present invention is not limited to this, and can be applied to the positioning of the movable part of various machine tools. It can be widely applied to various uses other than the positioning of the movable part.

[0040]

As is apparent from the above description,
According to the present invention, it is possible to take necessary precautions before the load becomes excessive depending on the state of the load on the driving means, and therefore, for example, the lubricating oil grease of the ball screw is reduced. In the case where the load gradually increases, the control means can recognize the load and reduce the load before the situation where the load becomes heavy and the situation becomes dangerous, and as a result, the load can be reduced. Thus, there is an effect that occurrence of mechanical damage and the like can be avoided beforehand.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment of a positioning device.

FIG. 2 is a flowchart showing the operation of the device of FIG.

FIG. 3 is a schematic view showing an example of a conventional one.

[Explanation of symbols]

 Reference Signs List 1 back gauge 2 main shaft 3 bevel gear 4 ball screw 10 positioning device 11 motor 12 pulse encoder 13 inverter 14 controller (PLC) 15 operation control unit 16 monitoring unit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G05B 19/404 G05B 19/404 K G05D 3/00 G05D 3/00 X F term (Reference) 3C011 AA14 5H209 AA06 BB08 CC01 DD06 GG01 HH02 HH10 5H269 AB01 BB11 EE11 EE13 EE25 GG01 GG06 5H303 AA01 BB01 BB06 BB11 DD02 DD25 DD27 FF09 HH04 JJ09 LL03

Claims (14)

[Claims] 1. A positioning method for transmitting an operation command from a control unit to a driving unit in accordance with an output of a detection unit for detecting a position of an object, and moving and positioning the object by operation of the driving unit, wherein the driving unit Monitoring the load condition by the control means, and when the load exceeds a predetermined value, the control means adjusts an operation command to the drive means so that the load is reduced. And a step of continuing the operation of the drive means. 2. The positioning method according to claim 1, wherein the adjustment of the operation command extends a predetermined acceleration / deceleration time during the acceleration / deceleration operation of the drive unit. 3. The positioning method according to claim 1, wherein the adjustment of the operation command reduces a predetermined operation speed when the driving means operates at a constant speed. 4. An operation command is transmitted from the control means to a drive control unit of the motor in accordance with an output of the detection means for detecting the position of the object, and the object is moved by the operation of the motor based on the control of the drive control unit. In the positioning method for positioning, by inputting an output state from the drive control unit to the motor to the control unit, a step of monitoring a state of a load applied to the motor by the control unit, and the load is determined in advance. A step of adjusting the driving command to the drive control unit so that the load is reduced when the value exceeds the value, so as to continue the operation of the motor. 5. A positioning device for transmitting an operation command from a controller to an inverter in accordance with an output of a pulse encoder for detecting a position of a movable portion of a machine tool, and moving and positioning the movable portion by operation of a motor based on control of the inverter. In the method, a state of a load applied to the motor is monitored by the controller by inputting an output state from the inverter to the motor to the controller, and when the load exceeds a predetermined value, A step in which the controller adjusts an operation command to the inverter so as to reduce the load, and continues the operation of the motor. 6. The positioning method according to claim 4, wherein the adjustment of the operation command extends a predetermined acceleration / deceleration time during the acceleration / deceleration operation of the motor. 7. The positioning method according to claim 4, wherein the adjustment of the operation command reduces a predetermined operation speed during a constant speed operation of the motor. 8. A positioning device for transmitting an operation command from a control unit to a driving unit in accordance with an output of a detection unit for detecting a position of an object, and moving and positioning the object by operation of the driving unit, wherein the driving unit Means for monitoring the state of the load according to, when the load exceeds a predetermined value, adjusting the operation command from the control means to the drive means so that the load is reduced, the drive means Means for continuing operation, a positioning device. 9. The positioning device according to claim 8, wherein the adjustment of the operation command extends a predetermined acceleration / deceleration time during the acceleration / deceleration operation of the drive unit. 10. The positioning apparatus according to claim 8, wherein the adjustment of the operation command reduces a predetermined operation speed when the driving means operates at a constant speed. 11. An operation command is transmitted from a control unit to a motor drive control unit in accordance with an output of a detection unit for detecting a position of an object, and the object is moved by the operation of the motor based on the control of the drive control unit. In a positioning device for positioning, by inputting an output status from the drive control unit to the motor to the control unit, a unit that monitors a status of a load applied to the motor, and the load exceeds a predetermined value. And a means for adjusting an operation command from the control means to the drive control unit so that the load is reduced, and continuing the operation of the motor. 12. A positioning device for transmitting an operation command from a controller to an inverter according to an output of a pulse encoder for detecting a position of a movable portion of a machine tool, and moving and positioning the movable portion by operation of a motor based on control of the inverter. In the apparatus, by inputting an output status from the inverter to the motor to the controller, a means for monitoring a status of a load applied to the motor by the controller, and when the load exceeds a predetermined value, Means for adjusting an operation command from the controller to the inverter so as to reduce the load and continuing the operation of the motor. 13. The positioning apparatus according to claim 11, wherein the adjustment of the operation command extends a predetermined acceleration / deceleration time during the acceleration / deceleration operation of the motor. 14. The positioning apparatus according to claim 11, wherein the adjustment of the operation command reduces a predetermined operation speed when the motor is operated at a constant speed.