JPH06556A - Feeder controller for press - Google Patents

Abstract

PURPOSE:To surely prevent the abnormality from generating by finding the press crank angle of the next time by using average velocity of press, and obtaining a feed forward amount by using this crank angle. CONSTITUTION:An average velocity of press which is formed when the variable amount of a shaft target value is changed from the state being zero to the state not being zero is stored in the storage means. While the variable amount of the shaft target value is changed from the state being zero to the state not being zero again, the press crank angle of the next time is found by using the average velocity of press stored in the storing means, and the feed forward amount is obtd. by using the found press crank angle of the next time by an arithmetic means. These storage means and arithmetic means are provided on the feeder controller for press. Therefore, the adverse influence on the feed forward amount due to the velocity variation of the press can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press feeder control device.

[0002]

2. Description of the Related Art A transfer feeder used in a press has a plurality of fingers attached to a pair of parallel feed bars, and the material is clamped by moving the pair of feed bars in a three-dimensional direction. Clamping operation, lifting operation to lift the material, advance operation to move the material to the next processing position, descending operation to lower the material, unclamping operation to release the material from the finger, return operation to return the feed bar to its original position. To carry the material.

The electronically controlled feeder of the mechanical feeder can arbitrarily change the stroke length and operating angle of each axis motion, so that complicated motion patterns can be dealt with easily and the setup change time is short. It is often used in machines.

FIG. 4 shows a general hardware configuration of a feeder control device under electronic control, and FIG. 5 shows an example of a motion pattern.

As shown in FIG. 4, the feeder control device is
A central processing unit (CPU) 1, a memory 2, a feed shaft drive unit 3, a clamp shaft drive unit 4, a lift shaft drive unit 5, a press synchro 6 for detecting a press crank angle, an A / D converter 7, and the like. ing. The feed shaft drive unit 3 is D
The A / A converter 8, the servo amplifier 9, the AC motor 10, the position sensor 11, the synchro 12, the A / D converter 13 and the like. The clamp shaft drive unit 4 and the lift shaft drive unit 5 also have the same configuration.

With this configuration, the servomotor positioning control of each axis (feed axis, clamp axis, lift axis) of the feeder device is performed in synchronization with the press crank angle (solid line in FIG. 5), so that there is no interference with the press. Each axis of the feeder device is controlled so as to operate on the locus of the motion diagram (feed axis; one-dot chain line in FIG. 5, clamp axis; broken line in FIG. 5, lift axis; two-dot chain line in FIG. 5). .

FIG. 6 shows a detailed structure of the feed shaft drive unit 3, the clamp shaft drive unit 4, and the lift shaft drive unit 5 including the CPU 1 of FIG. 4, and these are collectively referred to as a positioning controller 20. ing.

The press crank angle is detected by a press crank angle detector 6 such as synchro, and the detected value is analog-digital converted by an A / D converter 7 and input to a positioning controller 20. The feed shaft motion diagram table 21 stores in advance the target position of the feed shaft corresponding to the crank angle, and subtracts the feed shaft target position corresponding to the input press crank angle detection value as the feed shaft position command. Output to the container 22. The position signal of the motor 10 detected by the encoder 12 is fed back to the subtractor 22, and the subtractor 22 outputs the deviation thereof to the amplifier 23. The amplifier 23 amplifies the deviation with a predetermined position gain Gp and outputs it.

On the other hand, the position command output from the table 21 is input to the calculator 24, where the deviation between the current position command and the previous position command is calculated. The deviation is the amplifier 25
Input to the predetermined feedforward gain G
FF is applied. The adder 26 adds the position deviation obtained from the normal position deviation and the speed command by feedforward, and outputs the addition result to the servo amplifier 9 via the D / A converter 8. The detection signal of the position sensor 11 is fed back to the servo amplifier 9 by speed feedback. The clamp shaft and the lift shaft are also drive-controlled in the same manner.

As described above, in general feeder control, in order to realize accurate feeder control by reducing the deviation from the target value of the movement trajectory of each axis with respect to the press crank angle, position feedback of each axis is performed. Not only positioning control, but also speed control by feedforward is also used.
The formula for calculating F is as follows.

VF = ε · Gp + ΔL · GFF (1) ε; Position deviation Gp; Position gain ΔL; Target position change amount GFF; Feedforward gain Here, the press crank input via the A / D converter 7 The angle is fetched by the positioning controller 20 at regular intervals T (for example, 3 ms). In FIG. 7, Pn-1 is the press crank angle at the previous sampling timing tn-1, and Pn is the press crank angle at the current sampling timing tn. , Fn-1 is the press crank angle Pn-1
Axis target value on the motion diagram corresponding to, F
n is an axis target value on the motion diagram corresponding to the press crank angle Pn.

P ^ n + 1 is a value predicted as the press crank angle at the next sampling timing tn + 1, and this prediction calculation is executed at time tn according to the following equation (2).

[0013] That is, according to the above formula (2), the average press speed ΔP (however, the speed represents the amount of change in crank angle per fixed period T) is calculated using the press crank angle data for the past m times. By adding the current press crank angle Pn to the calculated average speed of the press, the press crank angle P ^ n + 1 at the next sampling time tn + 1 is predicted. Similarly, P ^ n is the press crank angle at the current sampling time tn predicted at the previous sampling time tn-1.

Further, F ^ n + 1 and F ^ n are axis target values on the motion diagram corresponding to these predicted press crank angles P ^ n + 1 and P ^ n.

Here, conventionally, in the above equation (1), the target value change amount ΔL has been defined as follows.

ΔL = F ^ n + 1−F ^ n (3)

[0017]

As described above, in the conventional apparatus, both the next target position F ^ n + 1 and the current target position F ^ n used to calculate the feedforward amount are predicted from the press average speed. Since the value is used, when the press speed fluctuates greatly, the speed command VF also fluctuates greatly due to the large fluctuation of (Fn + 1-Fn) in synchronization with this fluctuation, and the vibration and noise of the feeder. However, problems such as work transfer error and synchronization deviation occurred.

Further, in the conventional apparatus, the target press change amount ΔL used for calculating the feedforward amount is the expected press crank angle P ^ n + 1 obtained from the average press speed ΔP.
The average press speed Δ
If P fluctuates, the target value change amount ΔL is tracked accordingly.
As a result, the speed command VF also fluctuates significantly due to the influence of fluctuations, which causes the same problems as the above-described feeder vibration, noise, work transfer error, and synchronization deviation. This tendency is remarkable in a portion where the inclination of the motion pattern is steep.

The present invention has been made in view of the above situation, and causes each axis of the feeder device to be driven by a speed command that smoothly changes, thereby causing abnormalities such as vibration, noise, conveyance error, and synchronization deviation. An object of the present invention is to provide a feeder control device for a press that reliably prevents the press.

[0020]

According to the present invention,
Each of the feeder devices is calculated by calculating the feedforward amount based on the target value change amount of each axis of the feeder device corresponding to the press crank angle taken in every predetermined cycle and adding the position feedback deviation to the calculated feedforward amount. In the feeder control device for a press that calculates the speed command of the axis, the next press obtained by adding the feedforward amount to the fetched press crank angle and the press average speed obtained from the press crank angles for the past plural cycles Axis target position F ^ n + corresponding to crank angle
Axis target position Fn corresponding to the current press crank angle from 1
It is calculated by subtracting.

According to the configuration of the present invention, the feedforward amount is directly obtained from the predicted value F ^ n + 1 and the fetched crank crank angle data, instead of using the predicted value as in the prior art. It is determined based on the deviation (F ^ n + 1-F ^ n) from the axis target position Fn.

Further, in the present invention, from the axis target position corresponding to the next press crank angle obtained by adding the press average speed obtained from the press crank angles of the past plural cycles to the press crank angle taken in every predetermined cycle. The feed-forward amount is calculated based on the amount of change in the axis target value obtained by subtracting the axis target position corresponding to the current press crank angle, and the position feedback deviation is added to the calculated feed-forward amount to determine the feeder device. A press feeder control device for calculating a speed command for each axis, wherein the storage means stores the press average speed obtained when the axis target value change amount changes from 0 to a state other than 0. The storage means until the axis target value change amount changes from 0 again to a state other than 0. The stored using a press average speed seek the next press crank angle, so that comprise a calculating means for calculating the feedforward amount using the next press crank angle determined the.

According to such a configuration of the present invention, the target value change amount of each axis of the feeder device is constantly monitored, and the press speed when the target value change amount changes from 0 to a state other than 0 is stored. Before the change of the target axis value change amount from 0 to a state other than 0, the stored target press speed is used to calculate the change amount of the target axis value used for the feedforward amount calculation. To That is,
The feed-forward amount during the period when each axis of the feeder device is not stopped is calculated as follows:
Is calculated by using the next press crank angle obtained by using the press speed value that is a constant value when the state changes from the state of 0 to the state of 0 Prevent adverse effects.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings.

Also in the following embodiments, FIG. 4 and FIG.
It is assumed that the electronically controlled feeder control device shown in FIG.

First, a first embodiment of the present invention will be described with reference to FIGS.

FIG. 2 shows a motion pattern of the feed shaft of the feeder device. The feeder shaft is stopped in a section U1 where the press stroke is at the maximum position and a section U3 where the press stroke is at the 0 position. .

Here, the feedforward amount VFF is obtained by VFF = GFF · ΔL 'using the feedforward gain GFF and the target value change amount ΔL'.
In this embodiment, the target value change amount ΔL ′ is obtained according to the following equation (4) (see FIG. 7).

ΔL '= F ^ n + 1-Fn (4) F ^ n + 1 is a motion corresponding to the press crank angle P ^ n + 1 predicted to be taken at the next sampling timing tn + 1. The feed axis target value on the diagram, and Fn is the feed axis target value on the motion diagram corresponding to the press crank angle Pn captured at the sampling timing tn of this time.

In the sections U1 and U3 of FIG. 2, the target value change amount ΔL 'of the feeder axis is 0, but in the other sections U2 and U4, the target value change amount ΔL' is not 0.

In view of this, in the first embodiment, when the target value change amount ΔL 'changes from 0 (sections U1, U3) to a state other than 0 (two points t in FIG. 2).
The average press speed ΔP (denoted by a and tb) (the average speed obtained by using the press crank angle data for the past m times, refer to the equation (2)) is stored, and thereafter the target value change amount ΔL ′ becomes 0 again. Until the state is changed from the state of 1 to the state of not 0, the stored press average speed ΔP is used to obtain the target value change amount ΔL ′ used for calculating the feedforward amount VFF. For example, in FIG. 2, assuming that the press average speed at time ta is ΔP1, the target value change amount ΔL ′ is obtained using this average speed ΔP1 in the subsequent section U2, and the press average speed at time tb is ΔP2. Then, in the subsequent section U4, the target value change amount ΔL 'is obtained using this average speed ΔP2.

The feeder control according to the first embodiment will be described below with reference to the flowchart of FIG.

First, the positioning controller 20 takes in the detected value Pn of the press crank angle from the A / D converter 7 at time tn (step 100).

Next, the average speed ΔP of the press is calculated by using the detected values Pn-m + 1 to Pn of the past m press crank angles, and at time tn + 1 according to the above-mentioned equation (2). A predicted value P ^ n + 1 of the press crank angle is calculated (step 110).

Next, the feed-axis target values Fn and F ^ n + 1 corresponding to the press crank angles Pn and P ^ n + 1 thus obtained are set in the motion diagram table 2 described above.
Reading from 1 (step 120), these target values F
Using n and F ^ n + 1, the target value change amount ΔL '(= F ^ n + 1-
Fn) is obtained, and it is determined whether or not the target value change amount ΔL 'is 0 (step 130). If it is determined in this determination that the target value change amount ΔL ′ is not 0, the determination in step 140 is further executed.

The determination in step 140 is to detect the ta or tb portion of FIG. 2, and the target value change amount ΔL 'at the previous sampling time tn-1 is 0.
Then, the target value change amount Δ at the current sampling time tn
The sampling time when L'is 0 is detected.

Only when the determination in step 140 becomes YES, the positioning controller 20 stores the press average speed ΔP obtained at this sampling time in the memory 2 as the average speed value ω for calculating the feedforward amount VFF. (Step 150). At other times, that is, when the determination in step 130 is YES or the determination in step 140 is NO, the press average speed value ω stored before that is used to calculate the feedforward amount VFF.
Calculate the calculation.

In order to calculate the feedforward amount VFF, first, the current press crank angle Pn is added to the stored press average speed value ω to calculate the predicted press crank angle Pn at the next sampling time tn + 1. +1 is calculated (step 160). Next, the feed axis target value F¨n + 1 corresponding to the press crank angle P¨n + 1 thus obtained is set in the motion diagram table 2 above.
Read from 1 (step 120), and use this feed axis target value F-n + 1 to calculate the feedforward amount VFF
It is calculated according to (5) (step 180).

VFF = GFF (F.n + 1-Fn) (5) And the feedforward amount VFF thus obtained.
The speed command VF is calculated by adding the position deviation feedback amount ε · Gp to (see equation (1)).

Specifically, the feed axis current value Fn 'is read from the output of the encoder 12 (step 190),
The position deviation ε is obtained by subtracting this feed axis current value Fn ′ from the feed axis target value F ^ n + 1 at the next sampling time obtained in the previous step 120, and by multiplying this by the position gain Gp, the position deviation feedback is performed. The speed command VF is calculated by obtaining the amount ε · Gp and further adding the previously obtained feedforward amount VFF to this position deviation feedback amount ε · Gp (step 200).

When the drive control for the feed shaft is completed in this way, similar drive control is executed for the lift shaft and the clamp shaft.

Such control is repeatedly executed at each sampling time.

As described above, according to the first embodiment, the press average speed ω when the target value change amount ΔL ′ of the feeder changes from 0 to other than 0 is stored, and ΔL ′ becomes 0 thereafter. Since the stored one value ω is used to calculate the feedforward amount VFF during the period until
The press average speed for calculating the target value becomes constant, and thus the adverse effect on the feedforward amount due to the speed fluctuation of the press is eliminated.

FIG. 3 shows a second embodiment of the present invention, and the second embodiment will be described below according to the flow chart of FIG.
The feeder control according to the embodiment will be described.

First, the positioning controller 20 takes in the detected value Pn of the press crank angle from the A / D converter 7 at time tn (step 300).

Next, the average speed ΔP of the press is calculated by using the detected values Pn-m + 1 to Pn of the past m press crank angles, and at time tn + 1 according to the above-mentioned equation (2). A predicted value P ^ n + 1 of the press crank angle is calculated (step 310).

Next, the feed axis target values Fn and F ^ n + 1 corresponding to the press crank angles Pn and P ^ n + 1 thus obtained are set in the motion diagram table 2 described above.
Read from 1 (step 320), these target values F
Using n and F ^ n + 1, the target value change amount ΔL '(= F ^ n + 1-
Fn) is calculated, and the feedforward amount VFF is calculated according to the following equation (6) using the calculated target value change amount ΔL '(step 330).

VFF = GFF · ΔL ′ = GFF (F ^ n + 1−Fn) (6) And the feedforward amount VFF thus obtained
The speed command VF is calculated by adding the position deviation feedback amount ε · Gp to (see equation (1)).

Specifically, the current feed axis value Fn 'is read from the output of the encoder 12, and the above step 320 is performed.
The position deviation ε is obtained by subtracting the feed axis current value Fn ′ from the feed axis target value F ^ n + 1 at the next sampling time obtained in step S1, and is multiplied by the position gain Gp to obtain the position deviation feedback amount ε · Gp. Seeking
Further, the speed command VF is calculated by adding the previously obtained feedforward amount VFF to the position deviation feedback amount ε · Gp (step 340).

When the drive control for the feed shaft is completed in this way, the same drive control is executed for the lift shaft and the clamp shaft.

Such control is repeatedly executed at each sampling time.

As described above, according to the second embodiment, the target value change amount ΔL 'of the feeder is obtained according to the above equation (4). It is possible to obtain a speed command that is more resistant to speed changes than in (1) and output a speed command that changes smoothly unless the average speed of the press changes extremely.

In the embodiment, the position deviation is F ^ n + 1-
Although it is determined by Fn ', the position deviation may be determined by Fn-Fn'.

[0054]

As described above, according to the present invention,
The target value change amount of each axis of the feeder device is constantly monitored, and the press speed when the target value change amount changes from 0 to a state other than 0 is stored, and the axis target value change amount is 0 again. During the period from the state of changing to the state of not being 0, the stored press speed is used to obtain the amount of change in the target axis value used for calculating the feedforward amount. It is possible to prevent an adverse effect on the amount, and thereby it is possible to reliably prevent the occurrence of abnormalities such as vibration, noise, conveyance error, and synchronization deviation.

According to the present invention, the feedforward amount is based on the deviation between the predicted value and the shaft target position Fn obtained directly from the press crank angle data, instead of using the predicted value as in the prior art. Since it is calculated, it is possible to give a speed command that changes smoothly even if the press average speed fluctuates, and vibration, noise, conveyance error,
It is possible to prevent the occurrence of abnormalities such as synchronization deviation.

[Brief description of drawings]

FIG. 1 is a flow chart showing a first embodiment of the present invention.

FIG. 2 is a graph for explaining the first embodiment of the present invention.

FIG. 3 is a flow chart showing a second embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a feeder control device.

FIG. 5 is a motion pattern diagram of a press crank shaft and feeder shafts.

FIG. 6 is a block diagram showing details of a positioning control unit of the feeder control device.

FIG. 7 is a graph showing a relationship between a press crank angle and a target value.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Central processing unit (CPU) 2 ... Memory 3 ... Feed shaft drive part 4 ... Clamp shaft drive part 5 ... Lift shaft drive part 6 ... Press synchronization 7 ... A / D converter 8 ... D / A converter 9 ... Servo amplifier 10 ... AC motor 11 ... Position sensor 12 ... Synchro 20 ... Positioning controller 21 ... Motion diagram table 25 ... NC program memory

Claims (2)

[Claims] 1. A present press from an axial target position corresponding to a next press crank angle obtained by adding a press crank angle taken in every predetermined period to a press average speed obtained from press crank angles for a plurality of past periods. The feedforward amount is calculated based on the amount of change in the axis target value obtained by subtracting the axis target position corresponding to the crank angle, and the position feedback deviation is added to the calculated feedforward amount to determine the amount of each axis of the feeder device. A press feeder control device for calculating a speed command, comprising: storage means for storing the press average speed obtained when the axis target value change amount changes from 0 to a state other than 0; Until the amount of change in the target value changes from 0 again to a state other than 0, the press stored in the storage means is changed. Seeking the next press crank angle using an average speed,
A feeder control device for a press, comprising: a calculating unit that calculates the feedforward amount using the calculated next press crank angle. 2. A feedforward amount is calculated based on a target value change amount of each axis of the feeder device corresponding to a press crank angle taken in every predetermined cycle, and a position feedback deviation is added to the calculated feedforward amount. In the feeder control device for a press that calculates the speed command of each axis of the feeder device, the feedforward amount is obtained by adding the press average speed obtained from the press crank angles for the past multiple cycles to the fetched press crank angle. The press feeder control device is characterized in that it is obtained by subtracting the axial target position corresponding to the current press crank angle from the axial target position corresponding to the next press crank angle that is obtained by the following.