JPH11202915A - Controller for automatic machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust the extent of acceleration and deceleration with an external signal. SOLUTION: When an acceleration/deceleration override value β(%) is specified with an external signal from a console panel or other external devices, the acceleration/deceleration override signal value that a PMC(programmable machine controller) has is updated. The controller performs a filtering process (acceleration/deceleration control) corresponding to the acceleration/deceleration override signal value that the PMC has. In an acceleration/deceleration override OFF state (or β=100), acceleration/deceleration control is performed with a time constant τ matching basic operation conditions and the speed outputted to a servo changes in the order of (a), (c), (e), and (g). When the external signal is inputted with β=β1(<100), a process is performed with an acceleration/ deceleration time constant τ1(>τ0) and the speed outputted to the serve changes in the order of (a), (d), (e), and (h). When the external signal is inputted with β=β2>100), the process is performed with an acceleration/deceleration time constant τ2(<τ0) and the speed outputted to the servo changes in the order of (a), (b), (e), and (f).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for controlling automatic machines such as various machine tools and processing machines. More specifically, the present invention is provided with means for adjusting the acceleration / deceleration of the automatic machines. It relates to a control device.

[0002]

2. Description of the Related Art When an automatic machine such as a machine tool or a processing machine is operated in accordance with an operation program that defines a machining path and the like, processing based on CNC software having a block configuration as shown in FIG. Performed internally.
As shown in the figure, the entire framework of the CNC software is roughly divided into an operation planning unit, each axis interpolation processing unit, and each axis filter processing unit.

[0003] The operation planning section is a section for creating an operation plan for an automatic machine in accordance with the contents specified by the operation program (moving target position, motion type, program speed, etc.). , An arc operation, a spline operation, etc.) and a program speed Vpr, an operation plan for each drive axis is created and output to each axis interpolation processing unit. For example, the XYZ table of the machine tool is + X
In the case where positioning is performed by moving linearly by the distance D in the direction at the program speed Vpr in the direction, an operation plan as shown in the graph I is created for the X axis. The horizontal axis of the graph I represents time, the vertical axis represents speed, and the moving distance D is equal to the area indicated by oblique lines.

When an override is specified for the moving speed, usually, the override is considered in the operation planning unit, and the product of the program speed Vpr and the override (percentage) is the command distance to the interpolation processing unit. Output.

[0005] Between the motion planning section and each axis interpolation processing section, there is provided a block functioning as an operation shutter for controlling the sending of the output from the motion planning section to the interpolation processing section. The operation shutter is opened each time an output indicating the speed of each axis is generated by the operation planning unit, and an output indicating the command speed of each axis is passed to the interpolation processing unit.

[0006] Upon receiving this output, the interpolation processing unit of each axis performs an interpolation process for each calculation processing cycle (ITP), calculates the amount of movement for each ITP, and outputs it to the filter processing unit. When the input to the interpolation processing unit is represented by graph I, the output of the interpolation processing is as shown in graph II. Similar to the graph I, the horizontal axis represents time, and the vertical axis represents speed. In graph II, an area equal to the travel distance D is divided into a number of segments generated for each ITP. The area of each segment represents the amount of movement for each ITP.

The filter processing unit of each axis performs a filtering process on the output of the interpolation processing unit with a predetermined time constant τ. This process is performed to control the acceleration / deceleration of the automatic machine to smooth the acceleration / deceleration operation. That is, from the filter processing unit of each axis, a movement command indicating a speed transition that completes acceleration and deceleration during the time constant τ is created for each ITP, and is output to each axis servo. Each axis servo controls a drive current of a servo motor of each axis (not shown) based on the movement command and the feedback signal.

[0008] The input to the filter processing unit is graph II
, The output of the filtering unit is the graph II
It looks like I. As in the graphs I and II, the horizontal axis represents time, and the vertical axis represents speed. In the graph III, the equal-height segment group input from the interpolation processing unit of each axis is partially converted into a non-height-segment group. The portion where the segment height gradually increases from 0 to Vpr (command speed) over time τ represents an acceleration operation, and Vpr
The portion where the segment height gradually decreases from (command speed) to 0 (positioning) represents a deceleration operation. The slope α of the envelope of the segment group during the acceleration / deceleration operation represents the acceleration of acceleration / deceleration.

[0009]

In the conventional control device, the value of the acceleration / deceleration time constant τ is assumed to be the most basic condition (the processing condition for a machine tool or a processing machine). A reference value has been set in consideration of maximizing the performance (maximum torque and the like) of the servomotor of each axis under the conditions. This reference value is initially set as a part of the CNC software for the above-described processing prior to the start of processing (start of reproduction of the processing program). The speed of deceleration could not be changed.

[0010] However, the optimum conditions for actually operating the automatic machine are not fixed, and various changes are made in accordance with the processing conditions and the like, causing inconvenience. For example, in an automatic machine such as a punch press machine that drives a shaft that moves a work to a punch position while sandwiching the work between work holders, the load varies according to the weight of the work.

Therefore, when the machine is operated under the initially set acceleration / deceleration constant, if the work is lighter than the assumed weight, the servomotor performance is not sufficiently exhibited. become. Conversely, if the work weight exceeds the weight assumed by the initial set value, the performance of the servomotor may be insufficient and the machining accuracy may be affected. In order to avoid such a situation, it is necessary to take measures such as interrupting the processing and resetting the acceleration / deceleration constant each time the weight of the workpiece changes, which is very inconvenient.

Accordingly, an object of the present invention is to solve the above-mentioned problems in the prior art. That is, an object of the present invention is to provide a control device for an automatic machine capable of easily changing the acceleration / deceleration operation according to the magnitude of a load by an external signal. And, through this, the present invention provides inefficiencies caused by insufficient performance of the servo motor,
Conversely, an attempt is made to avoid the influence of a reduction in machining accuracy caused by the acceleration / deceleration operation being performed under conditions that do not match the performance.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a process for acceleration / deceleration control included in software processing in an automatic machine control device for outputting a movement command relating to a drive shaft to a servo system based on software processing. The time constant can be set in advance as a parameter, and the set parameter can be adjusted by inputting an external signal to determine the time constant.

It is preferable that the adjustment of the parameter for determining the acceleration / deceleration time constant can be performed in the direction of increasing the parameter and in the direction of decreasing the parameter. It is preferable that the adjustment of the parameter can be performed by designating the adjustment ratio by an external signal. The external signal can be sent from, for example, an operation panel connected to the control device.

[0015]

FIG. 2 is a block diagram for explaining an outline of an automatic machine control device to which the present invention is applied. The main CPU 11 of the control device body 10 has a shared RAM 1 provided between the main CPU 11 and the digital servo control block 13.
2. PMC (Programmable Machine Controller) 2
0, a control block 50 by the CNC software (hereinafter abbreviated as “CNC software 50”) is bus-connected.

The CNC software 50 creates a movement command for each axis at a predetermined cycle based on the operation path, operation conditions, and the like specified by the machining program, and passes the movement command to the digital servo control block 13 via the shared RAM 12. The outline of the processing during this time is as described above with reference to FIG. However, as will be described later, in this embodiment, the acceleration / deceleration time constant τ in the filtering process can be variably set according to an override value specified by an operator or an external signal, reflecting the features of the present invention.

The digital servo control block 13 controls the servo amplifier 14 based on a movement command created under a designated acceleration / deceleration override value and a feedback signal obtained from a pulse coder (not shown). Supplies a drive current to the motor of each axis.

An I / O unit 30 is connected to the PMC 20, and an operation panel unit 40 is connected to the I / O unit 30. The operation panel unit 40 corresponds to the standard equipment, and other external devices 60 such as a user-created operation panel unit, a brake mechanism installed in a processing machine main body, various sensors, and the like can be connected (*). Mark). A portion 100 surrounded by a broken line represents a portion mainly involved in the transfer of the acceleration / deceleration override value data to the CNC software 50, and FIG. 3 shows a somewhat detailed block configuration.

Referring to FIG. 3, the PMC 20 has a block 21 of PMC management software (hereinafter abbreviated as “PMC management software 21”) and a block 22 of a PMC ladder program (hereinafter abbreviated as “PMC ladder program 22”). . In order to exchange data between the two, P
Blocks 23 and 24 of bit images are respectively provided on the output side and the input side when viewed from the MC management software 21.

Further, PMC ladder program 22 and CN
A block for mediating data exchange with the C software 50 as a block to the CNC output unit 25 and the CNC input unit 2
6 are provided. PMC ladder program 22
For example, it includes a machining program (described in a ladder format) created by a user. When the machining program is reproduced, the CNC software 50 is used to execute the above-described process for creating a movement command (operation plan to filtering process). The required data is passed.

I / O unit 3 connected to PMC 20
0 is prepared as, for example, an I / O card, and has a required number of input units 31, 33, 34 and output units 32, 35. These input / output units mediate various elements of the PMC management software 21 and the operation panel unit 40, respectively.
The elements that are equipped with 0 are keyboard 41, LED
42, various operation keys, switches 43 and the like.

The operation keys and switches 43 may include an emergency stop switch and a speed override value designating key as in the past, but in the present embodiment, an acceleration / deceleration override value setting key which was not conventionally provided is provided. It is included.

The input and output signals of the keyboard 41 and the LED 42 are coded, and
1. It is exchanged with the PMC management software 21 via the output unit 32. A signal from the keyboard 41 is converted into a bit image by the PMC management software 21 and passed to the PMC ladder program 22 via the block 23. Also, P
An LED-related signal (eg, designation of a lighting LED element) output from the MC ladder program 22 is passed to the PMC management software 23 via the block 24 as a bit image. The PMC management software 23 encodes this into a signal that can control the LED 42, and outputs the signal to the LED 4 via the output unit 32.
Hand over to 2.

On the other hand, the operation panel 40 is connected to the input unit 33 via a contact mechanism, and the input unit 33 is connected to the PMC.
PMC ladder program 22 without management software 23
It is connected to the. Further, the input unit 34 and the output unit 35
A block that mediates between the PMC ladder program 22 and the external device 60, and exchanges signals with them.
3 without any intervention.

When a key operation for designating an acceleration / deceleration override value β% (other than 100%) in the various operation keys and switches 43 is performed, the key operation is performed via the input unit 33 through the PMC.
The acceleration / deceleration override signal transmitted to the ladder program 22 is changed. Specifically, a register area indicating the ON / OFF state of the acceleration / deceleration override and the override value at the time of ON is set in the memory belonging to the block of the PMC ladder program 22. Initial setting value β0 is β0 = 100
(%).

The appropriate value of the acceleration / deceleration override value β input from the operation panel 40 is determined according to each case. For example, an appropriate acceleration / deceleration override value β can be obtained in advance with respect to a plurality of assumed processing conditions (eg, work weight type), and reflected in actual processing.

The acceleration / deceleration override value β can be changed by an external signal input to the control device 10 from another external device 60. That is, an external signal designating an acceleration / deceleration override value is input from the external device 60 to the input unit 34.
Is transmitted to the PMC ladder program 22 via
The acceleration / deceleration override signal of the PMC ladder program 22 is changed, and the override signal (β value)
Is updated. The external signal sent from the external device 60 may be, for example, a work type signal reflecting the weight of the work.

The reference value τ0 of the acceleration / deceleration time constant set in advance in the CNC software 60 can be set to a value which is considered to be optimal for the basic machining conditions as in the prior art.
Further, the override value can be changed in either the extension or the reduction of the acceleration / deceleration time constant τ. However, an appropriate upper limit may be provided. For example, in the case of a work moving axis of a punch press machine, a value assuming "a work having a standard weight" may be initially set as τ0.

FIG. 4 is a diagram showing a case where a CNC command is received from a PMC ladder program when a movement command creation command corresponding to an operation command of an axis (for example, a workpiece movement axis of a punch press) which is a target of acceleration / deceleration override is received. Software 5
0 is an outline of the processing performed prior to the start of the filtering processing.

First, the PMC is input via the CNC input unit 26.
The ladder program 22 is requested to output parameters related to acceleration / deceleration override (step S1). The acceleration / deceleration override-related parameter is a flag F (ON;
F = 1 / OFF; F = 0) and an acceleration / deceleration override value β. Subsequently, acceleration / deceleration override-related parameters are received from the PMC ladder program 22 via the CNC output unit 25 (step S2).

Next, in step S3, the value of the flag F is determined. If F = 0, the acceleration / deceleration time constant at the time of the filtering process uses the initial set value τ0 (step S4). On the other hand, if F = 1, a value obtained by multiplying the initial setting value τ0 by 100 / β is adopted as the acceleration / deceleration time constant during the filtering process (step S5). The filtering process itself is the same as the conventional one.

FIG. 5 shows that β = β1 (β1 <100), override off (same for β = 100), β = β2 (β
2 is a graph showing an example of transition of the speed represented by the output of the filtering process for each case of (2> 100). The graph shows three trapezoids, each corresponding to the envelope for the segments in graph III in FIG. The correspondence between each case and the transition of the trapezoidal speed is as follows. In addition, each trapezoid abef, aceg, ad
The areas of eh are equal to each other, and represent the total movement amount for the operation shown in FIG.

[Case of β = β1 (<100)] Speed change; a → d → e → h Acceleration / deceleration time constant; τ = τ1 (> τ0) [Acceleration / deceleration override off or case of β = 100]・ Speed transition; a → c → e → g ・ Acceleration / deceleration time constant; τ = τ0 [case of β = β2 (> 100)] ・ Speed transition; a → b → e → f ・ Acceleration / deceleration time constant; τ = τ2 (<τ0)

[0034]

As described above, according to the present invention,
A control device for an automatic machine capable of easily changing the acceleration / deceleration speed by an external signal is provided. Further, in the control device according to the present invention, unlike the conventional device, the acceleration / deceleration can be adjusted at any time even after the start of machining, in consideration of the magnitude of the load applied to the drive shaft. Therefore, it is easy to sufficiently exert the capability of the servomotor without adversely affecting the processing accuracy and the like.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an outline of a general block configuration of CNC software in an automatic machine.

FIG. 2 is a block diagram illustrating an outline of an automatic machine control device to which the present invention is applied.

FIG. 3 shows a portion 100 surrounded by a broken line in FIG.
It is the figure which showed the somewhat detailed block configuration.

FIG. 4 is a diagram showing a CNC software 50 when a movement command creation command corresponding to an operation command of an axis designated as an acceleration / deceleration override is received from a PMC ladder program.
Is a flowchart illustrating an outline of a process performed prior to the start of a filtering process.

FIG. 5: β = β1 (β1 <100), override off (same for β = 100), β = β2 (β2> 100)
7 is a graph showing an example of transition of the speed represented by the output of the filtering process for each case of FIG.

[Explanation of symbols]

 Reference Signs List 10 control device main unit 11 main CPU 12 shared RAM 20 PMC 21 PMC management software 22 PMC ladder program 23 bit image (output side) 24 bit image (input side) 25 to CNC output unit 26 to CNC input unit 30 I / O unit 31, 33, 34 Input unit 32, 35 Output unit 40 Operation panel unit 41 Keyboard 42 LED 43 Various operation keys and switches 50 CNC software 60 External device

Claims (4)

[Claims] 1. A control device for an automatic machine that outputs a movement command relating to a drive axis to a servo system that controls the drive axis based on software processing, wherein the software processing includes processing for acceleration / deceleration control. A time constant in the acceleration / deceleration control can be set in advance as a parameter related to the software processing, and the time constant in the acceleration / deceleration control is determined by adjusting the preset parameter by inputting an external signal. The control device, comprising acceleration / deceleration slow / fast adjustment means. 2. The control device for an automatic machine according to claim 1, wherein the adjustment of the parameter can be performed in a direction in which the parameter is increased or in a direction in which the parameter is decreased. 3. The automatic machine according to claim 1, wherein the adjustment of the preset parameter can be performed by designating a ratio to the preset parameter by the external signal. Control device. 4. The control device for an automatic machine according to claim 1, wherein the external signal can be issued from a control panel connected to the control device.