JPS63268006A - Numerical controller - Google Patents

Abstract

PURPOSE:To continue an operation by reducing the fast forwarding speed even in case the operating speed exceeds the droop allowable value after setting two different levels of droop allowable value. CONSTITUTION:1st and 2nd droop allowable values are set at the registers 7 and 8 respectively. In a fast forwarding state, the droop (d) exceeds the 1st droop allowable value and a state signal b1 is supplied to a main control part 1 from a comparator 9 in the form of the information on the excessive droop. Thus the part 1 outputs a servo command (a) for deceleration of a servo motor 5 and the motor is operated at a low speed. Then the droop (d) exceeds the 2nd droop allowable value and a state signal b2 is supplied to the part 1 from a comparator 10 as the alarm information on the excessive droop. Thus the part 1 outputs a servo command (a) to stop the motor 5 and the operation is stopped. When both signals b1 and b2 are supplied at one time, the preference is given to the signal b2.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is characterized in that, when the positional deviation of the servo system exceeds a permissible value during rapid traverse, operation is continued by reducing the rapid traverse speed. This invention relates to a numerical control device.

[Conventional technology]

FIG. 3 shows a schematic block diagram of a conventional numerical control device.

In the figure, 1 is the main control unit that outputs the servo command al""aN, 2-1 to 2-N are individually controlled by the servo commands a, ~aN, and the position deviation between the command position and the actual position is within the allowable value. The servo control units 3-1 to 3-N, which respectively output status signals b1 to bN to notify whether or not the condition is within the range, are servo motors individually controlled by the servo control units 2-1 to 2-N.

In such a device, the servo control units 2-1 to 2-N individually control the servo motors 3-1 to 3-N according to servo commands 31 to aN from the main control unit 1. Further, the servo control units 2-1 to 2-N are connected to the servo motors 3-1 to 3-N.
The droop value, which is the positional deviation between the actual position of H and the servo command al""aN, is monitored, and when this droop value becomes larger than the preset droop tolerance value, the status signal bt"bH is controlled as an excessive droop alarm notification. This causes the main control unit 1 to output the servo motors 3-1 to 3-1.
Outputs servo command al'''aN to stop 3-N.

Next, the status signal t in the servo control units 2-1 to 2-H
)+-bN output operation will be explained with reference to FIG.

The main control unit 1 outputs a servo command a, and an adder 5 calculates a droop d, which is the deviation between the servo command a and the feedback signal f, which is the actual position of the servo motor 3 output from the position detector 6. This droop d is output to the amplifier 4 and comparator 12. The amplifier 4 amplifies the droop d and drives the servo motor 3.

The comparator 12 compares the positional deviation tolerance value (hereinafter referred to as droop tolerance value) set in advance in the register 13 with the value of droop d, and if droop d exceeds the droop tolerance value, an excessive droop alarm notification is issued. Outputs a status signal.

In such a device, since there is a single allowable droop value, each time droop d exceeds that value and an excessive droop alarm notification is output as a status signal, the servo motor 3
had been stopped.

[Problems to be Solved by the Invention] In the conventional numerical control device described above, the servo motor 3 is stopped every time the droop d exceeds the droop tolerance value.
On the other hand, the operator had to restart it. Generally, there are two types of excessive droop conditions: those in which the servo system cannot operate, and those in which the servo system can operate if the command conditions are met.

In reality, the excessive droop notification is output mostly in the latter case, for example, when the servo motor runs out of power during fast forwarding. At this time, even if the driving speed is reduced, there is no problem in continuing driving. However, in the past, there was a problem in that all operations were stopped even if operation was possible by lowering the command speed.

[Means for solving problems]

In the present invention, the first setting means has a first positional deviation tolerance set, the second setting means has a second positional deviation tolerance larger than the first positional deviation tolerance, and a first comparator that compares the position deviation value of 1 with a first position deviation allowable value and outputs an excessive position deviation notification when the position deviation value is larger than the first position deviation allowable value; A second comparator is provided which compares the deviation value with a second positional deviation allowable value and outputs an excessive positional deviation alarm when the positional deviation value is larger than the second positional deviation allowable value.

[For production]

In the present invention, when an excessive position deviation notification is output, the main control section outputs a servo command to decelerate the servo motor, so the servo motor continues to operate without stopping.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In FIG. 1, the same or equivalent parts as in FIG. 4 are given the same reference numerals, and their explanations will be omitted. 7 is a register which is a first setting means in which a first droop tolerance value is set;
8 is a register that is a second setting means in which a second droop tolerance value larger than the first droop tolerance value is set; 9 is a register for setting droop when the value of droop d is greater than the first droop tolerance value of register 7; A comparator 10, which is a first comparator, outputs an excessive notification status signal bl, and outputs an excessive droop alarm notification status signal b2 when the value of droop d is larger than the second droop tolerance value of the register 8. This is a second comparator.

In such a device, when the droop d exceeds the first droop tolerance value during fast forwarding and the status signal b1 is input from the comparator 9 to the main control unit 1 as an excessive droop notification, the main control unit 1 controls the servo motor 5. A servo command a to decelerate is output, and operation is performed at a low speed. On the other hand, if the droop d exceeds the second droop tolerance, the comparator 10
When the status signal b2 is input to the main control unit 1 as an excessive droop alarm notification, the main control unit 1 controls the servo motor 5.
A servo command a is output to stop the operation. Note that when the status signals bl and b2 are input at the same time, priority is given to the status signal b2.

Next, the operation of the servo control section will be explained using the time chart shown in FIG. In Fig. 2(a), when the command speed rises as shown in ■, the speed of the servo motor 3 follows as shown in V under normal conditions, and the droop, which is the positional deviation, increases as shown in Fig. 2(b). It changes like D.

However, when the time is not normal, even if the command speed rises as shown in ■, the speed of the servo motor 3 has poor followability as shown in vl, and therefore the droop also reaches the first droop at time 1+ as shown in Dl. Suppose that the allowable value dl is exceeded. At this time,
A status signal b+ is output from the comparator 9 in FIG. 1 to the main control unit 1 as an excessive droop notification. by this,
The main controller 1 outputs a servo command a for speed change, and at time t
In step 2, the command speed is reduced to ■1. Correspondingly, the speed of the servo motor 3 approaches Vl as shown by Vl, and the droop also decreases from time 11 onwards as shown by Dl, and the operation continues because it becomes smaller than the droop tolerance value dl.

However, during machining operation, the droop tolerance d+
When the status signal b1 is input from the comparator 9 to the main control section 1, the main control section 1 outputs a servo command a to stop the operation of the servo motor 3, as in the conventional case.

This is because changing the machining conditions during machining operation will have an adverse effect on the extraction force Ω workpiece.

〔Effect of the invention〕

As explained above, in the present invention, the droop tolerance is set to 28
Type 1 is set and each case is detected by a comparator, so if the droop value exceeds the first droop tolerance value during rapid traverse, the servo command can be changed and the operation can be performed without stopping the servo motor. The operation can be continued, and the operation can be stopped if the second droop tolerance is exceeded.

For this reason, it is possible to deal with excessive droop values during fast forwarding due to power shortages, especially in areas with poor power conditions, and there is no need for human intervention to restart the device when the first droop tolerance value is exceeded. It has a significant effect on productivity improvement, such as being able to continue unmanned operation. Also,
In the case of an abnormal condition in which the second droop tolerance is exceeded, the abnormality can be detected and stopped as in the conventional case.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one embodiment of the numerical control device of the present invention, Fig. 2 is a time chart explaining the operation of the servo control section, Fig. 3 is a schematic diagram of a general numerical control device, and Fig. 4 is a block diagram of a conventional numerical control device. 1°...Main control unit, 2-1~2-N...Servo control unit, 3.3-1~3-N...Servo motor, 4...Amplifier, 5... ... Adder, 6... Position detector, T, 8... Register, 9.10... Fist comparator.

Claims (1)

[Claims] a first setting means in which a first positional deviation tolerance value is set;
A second setting means, in which a second positional deviation tolerance value larger than the first positional deviation tolerance value is set, compares the actual positional deviation value with the first positional deviation tolerance value, and determines that the positional deviation value is A first comparator outputs an excessive position deviation notification when the position deviation is larger than the first position deviation tolerance, and compares the actual position deviation value with the second position deviation tolerance, and compares the actual position deviation value with the second position deviation tolerance. a second comparator that outputs an excessive position deviation alarm notification when the position deviation is larger than an allowable value; and a second comparator that outputs a command to decelerate the servo motor when the excessive position deviation notification is input, and outputs a command to decelerate the servo motor, and A numerical control device characterized by comprising: a full control section that outputs a command to stop a servo motor when inputted.