JPH047603A - Numerical controller - Google Patents

Abstract

PURPOSE:To make a data table for stopping a shaft unnecessary by executing a shaft stopping process from time when the speed of a cam driving shaft becomes slow by using a deceleration process during the operation of a cam. CONSTITUTION:A speed monitoring part 11 reads present feed speed from a speed detecting part 9 by a shaft stop signal S2 sent from a shaft stop signal generating part 21, and when the absolute value of this feed speed becomes below speed set beforehand, it changes a switch 10 to a deceleration function generating part 12 side. A deceleration factor corresponding to the speed set in the speed monitoring part 11 is stored beforehand in the deceleration function generating part 12, and after the switch 10 is changed, it obtaines a position command value for stopping the cam driving shaft from a present position read out from a position detector 8, the speed read out from the speed monitoring part 11 and this deceleration factor corresponding to the present speed, and outputs it to a subtracter 2. Thus, the data table for stopping the shaft is not necessitated.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a numerical control system for controlling an axis (hereinafter referred to as a cam driving axis) in which the speed of a numerically controlled lathe or the like continuously performs an operation consisting of repeating positive and negative changes. Regarding the control device.

(Prior art) FIG. 4 is a block diagram showing an example of a numerical control device that controls a cam driving axis, in which a function generator 1 generates a position command value for cam driving and sends it to a subtracter 2. be done. The position command value output from the function generator 1 and the current position value detected by the position detector 8 attached to the motor 7 are subtracted by the subtracter 2, and then sent to the position controller 3 as a position deviation value. , is converted into a speed command value and sent to the subtracter 4. On the other hand, the current position value detected by the position pressure detector 8 is converted into a current feed speed by the speed detector 9 and sent to the subtracter 4. The speed command value output from the position control section 3 and the current feed speed output from the speed detection section 9 are subtracted by a subtracter 4, and the result is sent to the speed control section 5 as a speed deviation value. Then, the speed deviation value outputted from the subtracter 4 is converted into a current command value by the speed control section 5, and the current command value is converted into a current command value by the current control section 6.
The current is sent to the motor 7 and converted into a current that controls the motor 7.

FIG. 6 is a diagram showing an example of a cam operation in which ellipse machining is performed by synchronously controlling the rotational speed of the main shaft and the position of the feed axis, and in this case, the feed axis is the cam driving axis.

Recently, there has been a demand for high-speed and highly accurate cam operation as shown in Figure 6, and numerical control devices with such special functions have been proposed by the applicant as having a "following error detection function". ``Numerical control device with
No. 90173). FIG. 5 is a block diagram showing an example of the numerical control device corresponding to FIG. 4, and the same components are given the same reference numerals and the explanation will be omitted. The position command value of the feed axis corresponding to the rotational speed of the main shaft motor 16 is stored in advance in the position command value data table 13, and the pulses generated from the main shaft pulse generator 15 due to the rotation of the main shaft motor 16 are transmitted to the rotation angle detector 14. The data read number S1 corresponding to the rotational speed of the spindle motor 16 is sent to the data read controller 19. Then, the position command value corresponding to the data read signal Sl is read out from the position command value data table 13 by the data read controller 19 and sent to the subtracter 2, and thereafter the control explained in FIG. 4 is performed based on this value. It is now possible to If such control is performed, functions are not generated in real time, so cam operation can be performed at high speed and with high precision.

Conventionally, when stopping the cam driving shaft with the above-mentioned numerical control device, in the example shown in the fourth figure, the shaft stop signal generating section 21 sends the shaft stop signal S2 to the function generating section 1,
For example, the axis stop data table 17 shown in FIG. This is done by switching the switch 18 from the position command value data table 13 side to the axis stop data table 17 side and sending the axis stop data to the data read controller 19. Such deceleration processing is different from the control processing of the cam driving shaft, and is necessary to reduce the impact on the shaft drive system.

(Problems to be Solved by the Invention) In order to smoothly stop the cam driving shaft in the above-mentioned numerical control device shown in FIG. Since the function equation is complicated, several deceleration coefficients from the maximum speed of the cam driving shaft to the time of stop are stored in the memory in advance, and are read out according to the conditions when calculating the position command value to perform deceleration processing. Figure 7 & is an example of the deceleration curve and an example of the deceleration coefficient for each function generation period obtained from the deceleration curve. If the speed at that time is Vm (V3<Vy≦V2), the deceleration coefficient is α, and the next position command value x11 is obtained by the following equation (1).

xllll+1=・x, 10v1*α3...(1)
Furthermore, the next position command value×1+2 is obtained by the following equation (2).

X ma2” Xm+ +” Vll141
* (24= Xm+l(XIN+1 - Xml*
Q4...(2) Similarly, the position command value x m43 is obtained by the following equation (3).

X @+3 = Xll++12 ” VII+
2 * (! 5=Xm-2”(X--2-Xm-+)
*05...(3) Then, repeat the following until the cam driving shaft stops.

Based on this, it is determined which value of the deceleration coefficient to use according to the speed when the shaft stop signal is manually operated, and after that, the cam drive shaft is stopped by reading out the deceleration coefficient one by one and performing deceleration processing. However, in order to smoothly stop the cam driving shaft using such a method, it is necessary to store in advance a large number of deceleration coefficients from the maximum speed of the cam driving shaft to the time of stopping in the memory.

In addition, when using deceleration processing such as exponential deceleration in order to smoothly stop the cam driving axis with the numerical control device shown in Figure 5, the cam driving data written in the position command value data table should be used. A data table for stopping the shaft obtained from the final position command value and the deceleration curve as shown in FIG. 7 is created and used when stopping the cam driving shaft. As shown in Figure 8, during normal cam operation, the cam operation data written in the position command value data table is repeatedly used, but when the axis stop signal is manually input, the position command value is When the end of the operation data is reached, the cam operation data is switched to the shaft stop data. However, if you want to stop the cam driving axis smoothly using this method, it is necessary to create an axis stopping data table that corresponds to the position command value data table, so every time the cam driving data is changed, , it was necessary to recreate the data table for axis stop with deceleration processing.

The present invention was made in view of the above-mentioned circumstances, and an object of the present invention is to provide a numerical control device that can stop a cam driving shaft in a simple manner by utilizing the deceleration process during cam operation. Our goal is to provide the following.

(Means for Solving the Problems) The present invention relates to a numerical control device for controlling an axis whose speed continuously performs an operation consisting of repeating positive and negative speeds. This is achieved by providing an axis stopping means that reads out the detected feed speed of the axis after that, and switches to a predetermined axis stopping process when the absolute value of this feed speed becomes less than a preset speed. be done.

(Function) In the present invention, when the absolute value of the feed speed of the cam driving shaft becomes less than a preset speed, the shaft is switched to the shaft stop process, so that the deceleration coefficient from the set speed is reduced. You only need to have this in memory, and you can easily and stably stop the cam driving shaft.

(Embodiment) FIG. 1 is a block diagram showing an example of a numerical control device of the present invention in correspondence with FIG. 4, and the same components are given the same reference numerals and the explanation thereof will be omitted. The numerical control device of the present invention is newly provided with shaft stopping means consisting of a switch 10, a speed monitoring section 11, and a deceleration function generating section 12.

The speed monitoring section 11 uses the shaft stop signal S2 sent from the shaft stop signal generation section 21 (step 51 shown in the third figure).
52) Read the current feed speed from the speed detection unit 9 (step S3 in the third diagram), and when the absolute value of the feed speed becomes equal to or less than the preset speed (step S4 in the third diagram), turn the switch lO. It is switched to the deceleration function generating section 12 side (step S5 in the third diagram).

A deceleration coefficient corresponding to the speed set in the speed monitoring section 11 is stored in advance in the deceleration function generating section 12, and after switching the switch IO, the current position read from the position detector 8 and the deceleration coefficient from the speed monitoring section 11 are stored. A position command value for stopping the cam driving shaft is determined from the read speed and a deceleration coefficient corresponding to the current speed, and is sent to the subtracter 2.

FIG. 2 is a block diagram showing another example of the numerical control device of the present invention in correspondence with FIG. 5, and the same components are given the same reference numerals and the explanation thereof will be omitted. In the numerical control device of the present invention, an axis stopping means consisting of a switch lO, a speed monitoring section 11, and a deceleration function generating section 12 is newly provided in place of the conventional axis stopping data table 17, switch 18, and switch controller 20. There is.

The speed monitoring section 11 uses the shaft stop signal S2 sent from the shaft stop signal generation section 21 (step 51 shown in the third figure).
52) Read the current feed speed from the speed detection unit 9 (step S3 in the third diagram), and when the absolute value of the feed speed becomes equal to or less than the preset speed (step S4 in the third diagram), turn the switch lO. The controller 19 is switched to the data continuous controller 19 connected to the position command value data table 13 (step 55 in the third figure). Deceleration function generator 1
2 stores in advance a deceleration coefficient corresponding to the speed set in the speed monitoring section 11, and after switching the switch 0, the current position read from the position detector 8 and the speed monitoring section 11
A position command value for stopping the cam driving shaft is determined from the current feed speed read from the current feed speed and a deceleration coefficient corresponding to the current feed speed, and is sent to the subtracter 2.

For example, in FIG. 7, if the speed set in the speed monitor 191311 is v7, the deceleration coefficients stored in the deceleration function generator 12 are α8 and α9.

Then, the detected speed is vllll (Tap Vt > l
V, Il) and the current position is Xi, the position command value x, , 2 for stopping the cam driving shaft is determined by the following equation (4).

Not only can it be a normal rotary motor, but it can also be a near motor that outputs force as a linear motion.

(Effects of the Invention) As described above, the numerical control device of the present invention utilizes the deceleration process during cam operation and performs the shaft stopping process after the speed of the cam driving shaft becomes small. This eliminates the need for a data table and stores only the minimum necessary deceleration coefficients, thereby saving the effort of re-creating an axis stop data table and storing a large number of deceleration coefficients.

In this embodiment, the value determined by the speed detection section 9 from the value of the position detector 8 is used as the speed of the motor 7, which is the cam driving shaft. may be read by the speed monitoring unit 11. Also, as a cam driving shaft

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of the numerical control device of the present invention, FIG. 2 is a block diagram showing another example of the numerical control device of the present invention, and FIG. 3 is a block diagram showing the main parts of the numerical control device of the present invention. A flowchart showing an example of operation, Fig. 4 is a block diagram showing an example of a conventional numerical control device, Fig. 5 is a block diagram showing another example of a conventional numerical control device, and Fig. 6 shows an example of cam operation. 7 is a diagram showing an example of a damping curve and a deceleration coefficient, and FIG. 8 is a diagram showing a conventional example in which a cam driving shaft is stopped. DESCRIPTION OF SYMBOLS 1... Function generation part, 2... Subtractor, 3... Position control part, 4... Subtractor, 5... Speed control part, 6...
Current control unit, 7... Motor, 8... Position detector, 9
...Speed detection unit, 10...Switch, 11...Speed monitoring unit, 12...Deceleration function generation unit, 13...Value data table for position command, 14...Rotation angle detection unit,
15... Pulse generator, 16... Main shaft motor, 17... Axis stop data table, 18... Switch, 19... Data read controller, 20...
Switch controller, 21...axis stop signal generation section.

Claims (1)

[Claims] 1. In a numerical control device that controls an axis that continuously performs an operation whose speed is made up of repeating positive and negative changes, after inputting an axis stop signal, the detected feed rate of the axis is read out, and the absolute value of this feed rate is set in advance. A numerical control device characterized by comprising a shaft stopping means that switches to a predetermined shaft stopping process when the speed drops below the specified speed.