KR20030091668A - Work transfer equipment and method for controlling same - Google Patents

Abstract

SUMMARY OF THE INVENTION An object of the present invention is to provide a workpiece transporting apparatus and a control method by servomotor driving of a transfer press capable of eliminating interference due to synchronous misalignment without being affected by press vibration.

As a means for solving the above problems, a press angle detector 11 for detecting a press angle corresponding to a slide position in one cycle, and a vibration component of the detected press angle signal according to a parameter that can be set at an arbitrary time point A vibration suppression section 24 for outputting a press angle signal in which the vibration component is removed and a parameter setting section for selectively changing the parameters of the vibration suppression section 24 in a real word. 23) and a motion servo calculating section 25 for controlling the rotation of the servomotor in synchronization with the press angle signal from which the vibration component from the vibration suppressing section 24 is removed.

Description

WORK TRANSFER EQUIPMENT AND METHOD FOR CONTROLLING SAME}

The present invention relates to a workpiece conveying apparatus and a control method thereof by driving a servo motor of a transfer press.

The transfer feeder, which is conventionally used as a workpiece conveying device for a transfer press, has a pair of left and right feed bars in the workpiece conveying direction, and the pair of left and right feed bars are synchronized with the lifting operation of the slide of the transfer press as shown in FIG. The conveyance direction (advanced direction and return direction), and the up-down direction (up and down) and the left-right direction (clamp and unclamp) are moved, respectively. In order to flexibly respond to the production of small quantities of various products in recent years, the stroke lengths in the three axis directions (referred to as feed shafts, lift shafts, and clamp shafts), and the timing of the motions of the slides can be appropriately controlled according to the workpieces. In order to be able to drive each axis by an electric servo motor, a servo transfer feeder is widely used.

The configuration of the control apparatus of the conventional servotransfer feeder will be described with reference to FIG. The crank angle (hereinafter simply referred to as the press angle) of the slide for synchronizing with the slide is detected by, for example, the press angle detector 11 made of a rotary encoder. Each axis servomotor 14, 16, 18 for driving the feed shaft, the lift shaft, and the clamp shaft, respectively, is controlled by the corresponding respective axis servo amplifiers 13, 15, 17. The controller 10 stores, in advance, motion data indicating the relationship between the press angle and the stroke position of each axis in accordance with the workpiece. The controller 10 presses the detector 11 at a predetermined servo operation cycle during actual machining. The servo angle command and the speed command are calculated by inputting the detected press angle with) to obtain the stroke positions of the three axes corresponding to the press angles from the motion data, and to move them at the predetermined speeds to the obtained stroke positions. And output to the respective axis servo amplifiers 13, 15 and 17. In addition, a pulse encoder (not shown) is attached to each of the axis servomotors 14, 16 and 18, and is fed back to each axis servo amplifier 13, 15 and 17 as a speed signal and a position signal, respectively.

According to the above configuration, since the three axes of the feed shaft, the lift shaft, and the clamp shaft are positioned in accordance with a preset motion curve in synchronization with the press angle of the slide, the transfer feeder can convey the workpiece to the next step without interference in synchronization with the slide. .

On the other hand, vibration is generated in the frame of the press body due to the slide pressing force or the reaction of the pressing force dropping during molding processing near the slide dead center. Since the press angle detector 11 is connected to the intermediate shaft of the drive system of the crankshaft through the coupling, the vibration of the connected intermediate shaft is generated under the influence of the vibration of the main frame, and thereby the press angle detector 11 In the press angle signal detected by), a vibrating signal is mixed as noise. For this reason, the controller tries to control the motion of each axis faithfully in synchronism with the vibration of the press angle signal, so that the behavior of each axis becomes vibratory, and in particular, the vibration and noise during the return of the feed shaft to the stroke A shown in FIG. There is a problem in that the servomotor 14 is overloaded and overloaded.

In order to solve such a problem, it is proposed to have a vibration suppressing function of removing the vibration component of the press angle signal to obtain a smooth signal, thereby suppressing the vibration of each axis behavior. It is equipped with a low-pass-filter vibration suppression unit that cuts the high frequency region of the signal at the input angle of the press-angle signal, and the press-angle signal from which noise is removed from the vibration suppression unit is removed. To control each axis motion in synchronization with. This eliminates the influence of the vibration of the main body frame and eliminates the vibration of each axis motion of the transfer feeder.

However, in the case of the control using the conventional vibration suppression function, since the set value of the control parameter for determining the degree of the suppression effect of the vibration suppression part is constant, the vibration suppression effect is always large, that is, the equivalent high frequency region signal of the vibration suppression part. The cut frequency is set to a low region. For this reason, the behavior during the one-cycle operation of the transfer feeder is smoothly controlled without being affected by the press vibration, but on the other hand, the amount of deviation in the motion curve of each axis set in advance throughout the conveyance stroke is large. That is, the deviation of the press angle signal obtained along with the high frequency region cut of the press angle signal is caused to the actual press angle, and the motion at the time of the actual word of each axis causes the synchronous deviation.

Therefore, depending on the type of workpiece, the stroke length of each axis and the timing of the operation must be set precisely so that there is no interference between the motion of each axis and the mold in relation to the shape, size, distance between processes, etc. of the mold. Although position servo control may be required, in this case, if the synchronization of the motion of the actual assist of each axis occurs as described above, there is a possibility that interference between the hand of the transfer feeder, the workpiece and the mold may occur. In order to avoid this, on the contrary, if the vibration suppression effect is small (set the equivalent high-frequency cut frequency in a high region) throughout the conveyance stroke, it is susceptible to press vibration and causes insufficient vibration suppression on each axis. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object thereof is to provide a workpiece transport apparatus and a method of controlling the same by a servo motor drive of a transfer press capable of eliminating interference due to synchronous deviation of motion without being affected by press vibration. do.

1 is a hardware block diagram of a control device according to the present invention;

2 is a block diagram of a control function according to the present invention;

3 is a control flowchart according to the embodiment;

4 is an explanatory diagram of a vibration suppression effect.

5 is an explanatory diagram of each axis operation of the workpiece conveyance apparatus.

6 is a hardware block diagram of a conventional servotransfer feeder control apparatus.

[Description of Signs of Important Parts of Drawing]

Reference Signs List 10 controller 10 press angle detector 12 press angle detector

13: Feed axis servo amplifier 14: Feed axis servo motor 15: Lift axis servo amplifier

16: lift shaft servomotor 17: clamp shaft servo amplifier 18: clamp shaft servomotor

20: controller 21: press angle input unit 22: press angle input unit

23: parameter setting unit 24: vibration suppression unit 25: motion servo operation unit

26: set motion memory

In order to achieve the above object, the first invention is a press angle detector for detecting a press angle corresponding to a slide position in one cycle in a workpiece transport apparatus driven by servo-mutter driving of a transfer press, and can be set at any time. A vibration suppression unit for outputting a press angle signal from which the vibration component is removed by varying the effect of removing the vibration component of the detected press angle signal according to the determined parameter; A parameter setting unit for selectively changing negative parameters and a motion servo operation unit for controlling rotation of the servomotor in synchronization with a press angle signal from which the vibration component is removed from the vibration suppressing unit are provided.

According to the first invention, since the effect of removing the vibration component of the press angle signal in the vibration suppression unit can be changed by selectively changing the parameter of the vibration suppression unit in the actual fish, the influence of vibration during press molding is large. The stroke can eliminate the influence of the vibration during the servomotor control of the workpiece transporter by increasing the above effect, and the servomotor control of the workpiece transporter can be reduced while the stroke is less affected by the vibration during press molding. The misalignment of the motion can be reduced. Therefore, the work conveying device can be controlled by suppressing the influence of press vibration at an appropriate timing.

According to the second aspect of the present invention, in the method of controlling a workpiece transport apparatus by driving a servo motor of a transfer press, the effect of vibration suppression for removing the vibration component of the press angle signal detected by the press angle detector is selectively changed, and according to this effect. The rotation of the servomotor is controlled in synchronization with the press angle signal from which the vibration component is removed.

According to the second aspect of the present invention, the effect of removing the vibration component of the press angle signal can be selectively selected during the actual control, so that the above-mentioned effect is increased in the stroke having a large influence of the vibration during press molding, so that the workpiece caused by this vibration The influence of vibration at the time of servo motor control of the conveying apparatus can be eliminated, and in the stroke where the influence of vibration at the time of press molding is small, the said effect can be reduced, and the synchronous shift of the motion of the servo motor control of a workpiece conveyance apparatus can be reduced. Therefore, the work conveying device can be controlled by suppressing the influence of press vibration at an appropriate timing.

In the third invention, in the second invention, the effect of the vibration suppression is changed according to the press angle range.

According to the third invention, the large press vibration is usually the range of the press stroke from just before the start of molding to just after the end of molding, and this corresponds to a predetermined press angle range (for example, 170 to 200 degrees) under control, and thus this press angle. Since the effect of vibration suppression is changed according to the range, it is possible to alternately control the suppression of vibration suppression and the amount of deviation of the synchronization of motion in a simple manner.

According to a fourth aspect of the invention, in the third invention, the vibration suppression effect is set to be small during the control in the advance direction, and the vibration suppression effect is set to be large during the control in the return direction.

According to the fourth aspect of the invention, since there is no press vibration during the advance operation of the workpiece conveyance device, by controlling the effect of vibration suppression to be small, the amount of synchronous displacement of the motion can be reduced to prevent interference with the mold or the slide, and the return operation. When there is no possibility of interference with mold or slide, press vibration is large, and the effect of vibration suppression is set to be large so that the noise is not affected by press vibration and the overload of servo motor is prevented without being affected by press vibration. .

[Examples of the Invention]

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 4.

1 is a block diagram showing the hardware configuration of a control device according to the present invention. In addition, in FIG. 1, the same code | symbol is attached | subjected to the component same as the component of FIG. 6, The description is abbreviate | omitted below.

The first press angle detector 11 and the second press angle detector 12 are provided. The first press angle detector 11 detects the press angle θa (corresponding to the crank rotation angle of the slide) for controlling the workpiece transporting device in synchronization with the slide operation, and for example, the motion control of the workpiece transporting device such as a rotary encoder. It is comprised by the rotation sensor which can detect a crank rotation angle with the predetermined pulse resolution which can fully acquire position precision. The second press angle detector 12 detects the press angle θb used for the determination of the press angle range at the timing of changing the effect of the vibration suppression control, and in this example, for example, a rotary having a configuration that is hard to be affected by the press vibration. It consists of a cam device. The rotary cam device includes a general rotary cam mechanism having a plurality of cams mounted on a rotary shaft connected to an intermediate side of a slide drive system that rotates in synchronism with the crank shaft, and a limit switch operated by the plurality of cams. The press angle range at which the limit switch operates is configured to be set arbitrarily. Signals of the respective press angles θa and θb are input to the controller 20.

The controller 20 has a high speed computing device such as a computer device or a programmable logic controller (so-called PLC). The controller 20 stores, in advance, motion data indicating the relationship between the press angle and the stroke position of each axis (feed axis, lift axis, clamp axis) in accordance with the workpiece. The press angles θa and θb are input at every servo operation cycle during actual machining, and the stroke positions of three axes corresponding to the synchronous press angles θa are obtained from the motion data, respectively, and are respectively determined at the respective stroke positions obtained. Each axis servo position command and speed command are calculated so as to move at a speed, and outputted to each axis servo amplifier 13, 15, 17, and the predetermined angle described later on the basis of the press angle θb for the change timing of the vibration suppression control. A calculation process is performed to change the vibration suppression effect in the servo control of each axis.

Fig. 2 is a block diagram of a control function according to the present invention. Fig. 2 illustrates each control function.

The first press angle input unit 21 inputs the press angle θa detected by the first press angle detector 11 and outputs it to the vibration suppressing unit 24.

The second press angle input section 22 inputs the detected press angle θb of the second press angle detector 12 and outputs it to the parameter setting section 23.

The parameter setting section 23 sets the parameters of the vibration suppressing section 24 in accordance with the press angle θb. That is, a plurality of press angle ranges and parameter setting values corresponding to the ranges are stored in advance, and in actual operation, the press angle ranges including the input press angle θb are calculated and the parameter setting values corresponding to the press angle ranges are calculated. Is output to the vibration suppressing section 24 and the parameters of the vibration suppressing section 24 are set. In the present embodiment, two press angle ranges between the first range of θ 1 to θ 2 (for example, 170 to 200 degrees including the press bottom dead center (180 degrees)) and the second range other than that In the first range, each parameter of each range is set so that the vibration suppression effect is a magnitude corresponding to the amount of vibration in forming the workpiece, and in the second range, the vibration suppression effect is small.

The vibration suppressing part 24 is a so-called low pass filter that cuts (ie, suppresses) a high frequency vibration component of a predetermined frequency or more with respect to the signal of the press angle θ a input from the first press angle input part 21. ) Has the function. At this time, the filter characteristics such as the cut frequency and the attenuation tendency of the signal gain in the high range are determined by the parameters set by the parameter setting section 23. As a result, the press angle signal θ s from which the high frequency vibration component of the predetermined frequency or more is removed is output to the motion servo calculating section 25.

The set motion memory 26 stores motion data of each axis (feed axis, lift axis, clamp axis) set in advance for each workpiece. As the motion data, the stroke length of each axis, the operation start press angle and the operation end press angle of the stroke, and the like are set. The relationship between the press angle and the motion of each axis is determined based on these motion data.

The motion servo calculation section 25 calculates a motion curve obtained from the motion data stored in the set motion memory section 26, and calculates the motion image of each axis corresponding to the press angle signal θ s input from the vibration suppressing section 24. The position is obtained by the calculated motion curve. Thus, each axis target position is calculated based on the motion position of each axis, and output to each axis servo amplifier 13, 15, 17, respectively.

Next, the control procedure will be explained by the flow chart shown in FIG.

First, the press angles θa and θb are input in step S1. (Press angle input sections 21 and 22) Next, in step S2, it is checked whether the press angle θb satisfies " θ1 ≤ θb ≤ θ2 '', and when it is satisfied, step S3. In step S4, the parameter is set so that the vibration suppression effect is large, and when it is not satisfied, the parameter is set so that the vibration suppression effect is small. (Parameter setting unit 23) Next, on the basis of the filter characteristic determined by this set parameter in step S5, the press angle θ s obtained by removing the signal of the high frequency region of the input press angle θ a is obtained. (Vibration suppressing section 24) Based on the press angle θs obtained in step S6, the target position command value of each axis servo is calculated from the preset motion data, and the command is sent to each axis servo amplifier 13 (15) in step S7. Are output to (17), and then (Motion Servo Computing Unit 25), the process returns to Step S1 and the above process is repeated.

Next, the effect by this embodiment is demonstrated with reference to FIG. Fig. 4 is an explanatory view of the vibration suppression effect, and Fig. 4 (a) shows the press speed, that is, the rotation speed of the press angle detector 11, and Fig. 4 (b) shows the vibration suppression effect according to the prior art in all conveyance strokes. In Fig. 4 (c), the feed shaft speed according to the present invention is shown.

Since the magnitude of the vibration suppression effect of the vibration suppression portion 24, that is, a parameter for determining filter characteristics is selectively changed during actual control, positioning accuracy with respect to the motion of each axis that is changed by each stroke of the workpiece transporter. The vibration suppression effect can be set at an appropriate timing in accordance with each conveying stroke in consideration of the required degree of control and the influence of the press vibration.

At this time, as shown in Fig. 4 (a), conveying a predetermined press angle range immediately after the completion of molding from just before the start of press molding with a bottom dead center (press angle = 180 degrees) interposed therebetween. In the stroke Fr (in many cases, the return stroke), the press vibration is large, so the variation in the press speed is large. On the contrary, there is little possibility of interference with the mold, so the synchronous accuracy with the press angle is not strict. For this reason, the influence of the vibration component of the signal of the press angle θa due to the press vibration is eliminated by setting the parameter so that the vibration suppressing effect in the conveying stroke Fr is increased, and as shown in FIG. In addition, it is possible to reduce the noise and thus to prevent overloading of the respective servomotors 14, 16 and 18 in advance.

On the other hand, in the press angle range conveying stroke Fa other than the above, as shown in Fig. 4 (a), the press vibration is small, but each axis is often moved in the slide operation space, that is, the space between the upper and lower molds. Synchronous precision is strict. For this reason, as shown in Fig. 4 (c), by setting the parameter so that the vibration suppressing effect is small in the conveying stroke Fa, the amount of synchronous shift in the set motion during stroke control of each axis can be reduced. This makes it possible to reliably prevent interference between the workpiece conveyance device and the mold or slide in the vicinity of the mold.

As such, since the vibration suppression effect is selectively changed according to each conveying stroke, the synchronous precision and the suppressing effect suitable for each conveying stroke are obtained. That is, conventionally, for example, as shown in Fig. 4 (b), when all parameters are set to constant parameters in all of the transfer strokes in which the vibration suppression effect is reduced by focusing on the synchronous precision side, each axis (in this case, the feed shaft) stroke of the transfer stroke Fr is stroked. Vibration occurs during control. According to the present invention, it is possible to obtain the vibration suppression effect in the conveying stroke Fr with a large press vibration and the synchronous precision in the conveying stroke Fa. Therefore, it is possible to smoothly control the angular stroke of the workpiece conveyance device without being affected by press vibration in a motion suitable for the shape and size of various molds.

Since the vibration suppression effect is changed according to a predetermined press angle range, each press angle range and its vibration suppression effect are set according to the conveying stroke, so that the control having the suppression effect and the motion synchronous precision suitable for each conveying stroke can be easily performed. can do.

In the above embodiment, the number of conveying strokes (press angle ranges) for changing the vibration suppression effect is set as two examples in one cycle. However, the main purpose of the present invention is not limited to two, but at least two or more. . In this case, by setting the press angle range in a plurality of stages, it is possible to avoid a sudden position change by gradually changing the magnitude of the synchronous shift amount in the set motion.

In addition, the press angle θa for synchronous control and the press angle θb for controlling the timing for changing the vibration suppression effect are detected by the other press angle detectors 11 and 12, respectively. The signal obtained by the angle? A signal through the predetermined low pass filter may be used as the press angle? B signal for timing control of the vibration suppression effect change. In this case, the press angle range for determining the timing of the vibration suppression effect change may be set with a predetermined margin.

In the above embodiment, a mechanical rotary cam with a cam and a limit switch is used, but an electric rotary cam may be used. The use of an electric rotary cam makes it easy to change the setting of the press angle range.

In addition, although each servomotor is provided in each axis of the workpiece conveyance apparatus, several servomotors may be provided.

In addition, as an example of the workpiece conveying apparatus, a transfer feeder that synchronously drives two feed bars in the feed shaft, the lift shaft, and the clamp shaft direction has been described. However, the present invention is not limited thereto, and the feed shaft and the lift shaft may be driven by two axes. A plurality of carriers, which are movable along the longitudinal direction (feed axis) of the beam, are installed on the lift beam, which is movable in the direction (lift axis), and crossbars are installed between the opposite carriers, and the respective crossbars are adsorbed by vacuum or the like. It may be of a crossbar type provided with a gripping means enabled.

As described above, according to the present invention, the following effects are obtained.

In the control function of the vibration suppressing unit that removes the vibration component of the press angle signal due to the press vibration, the effect is changed to a predetermined value in a plurality of predetermined ranges in one press cycle. By arbitrarily setting the range in which the suppression effect is required, both can be appropriately set in accordance with the conveyance administration. Therefore, the appropriate motion can be set for each workpiece, and the motion of the workpiece transporter can be smoothly controlled without being affected by press vibration, thereby reducing noise and preventing overload of the servomotor.

Further, since the change timing of the vibration suppression effect is set according to the press angle range, it is possible to alternately control the suppression of vibration suppression and the amount of synchronous shift of motion appropriately by a simple method.

In addition, by controlling the vibration suppression effect to a small setting during the advance operation of the workpiece transporter, the amount of synchronous shift of the motion can be reduced to prevent interference with a mold or a slide. Therefore, it is possible to reduce noise and prevent overload of servo motor in workpiece conveyance control without being affected by press vibration.

Claims (4)

In the workpiece conveying apparatus by servo motor driving of transfer press A press angle detector 11 for detecting a press angle corresponding to a slide position in one cycle; A vibration suppressing unit 24 for varying an effect of removing the vibration component of the detected press angle signal according to a parameter that can be set at any time and outputting a press angle signal from which the vibration component has been removed; A parameter setting unit 23 for selectively changing the parameters of the vibration suppressing unit 24 in the actual language, Workpiece by driving the servo motor of the transfer press, characterized in that it comprises a motion servo operation unit 25 for controlling the rotation of the servo motor in synchronization with the press angle signal from which the vibration component from the vibration suppressing unit 24 is removed. Conveying device. In the control method of the workpiece conveyance apparatus by driving the servo motor of the transfer press, Selectively changes the vibration suppression effect of removing vibration components of the press angle signal detected by the press angle detector 11, According to this effect, the rotation of the servomotor is controlled in synchronization with the press angle signal from which the vibration component is removed. 3. The method according to claim 2, wherein the effect of the vibration suppression is changed according to the press angle range. The servomotor drive of a transfer press according to claim 3, wherein the effect of the vibration suppression is set small during the control in the advance direction and the effect of the vibration suppression is set large during the control in the return direction. Control method of workpiece conveying apparatus