JPH11267899A - Control device for servo press - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a servo press, which can hold a high speed slide elevating movement, obtain a required molding pressure during molding, and improve product accuracy and productivity. SOLUTION: Based on the signal of a vibration sensor 13 detecting the vibration of a servo press main body, specific frequency and a maximum output value of the molding are outputted from a frequency assumption part 22, and are compared with the data which is calculated in advance or obtained by trial punching, so as to input the signal of a comparator 23 outputted when the data are matched, in to a selector 28. From the condition that a machine driving torque 27 computed based on the set servo amplifier maximum current 26 is selected so as to process the slide at high speed, the molding torque computed from the set molding pressure 29 is selected, so as to lower the slide at a required molding pressure. Further, when a bottom dead point judge 25 outputs the bottom dead point signal from the slide position and the speed information computed based on the output of an encoder 10, the machine driving torque 27 is again selected, so as to rise the slide at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo press controller for moving a slide up and down by using a servo motor as a drive source, and more particularly to controlling a molding pressure in a press molding region of a slide and a slide speed in a non-press molding region. A control device for a servo press capable of controlling the speed of a servo press at a high speed is effective for improving product accuracy and improving production efficiency.

[0002]

2. Description of the Related Art In order to control a molding pressure in a press molding region, a servo press that moves a slide up and down by using a servomotor as a driving source is uniformly limited to a motor generated torque corresponding to the molding pressure even in a non-press molding region. As a result, low-speed response control was performed over the entire slide operation area. Also, the slide position of the molding start point was set to start controlling the molding pressure, the molding pressure control was ended at the bottom dead center position, and the slide speed was controlled at a high speed from the bottom dead center to the next molding start point. .

[0003]

In the above-mentioned prior art,
Since the motor generated torque corresponding to the molding pressure is limited in the entire slide operation area, the actual motor speed causes a response delay to a sudden position and speed command, and high-speed slide up and down movement can be performed. And productivity was reduced. Although the slide position of the molding start point is set, the mold expands due to heat generated by molding and the molding start point is displaced, or the molding start point is displaced due to an error in the thickness of the material supplied to the mold. I do. Due to these factors, if the molding starting point is earlier and the pressing force control is delayed, the molding is unreasonable, the product accuracy is reduced, and defective products are generated. In order to avoid this, if the slide position of the molding start point is set high in advance, there is a drawback that the time required for one stroke of the slide increases and the productivity decreases.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to control the molding pressure during molding to a required set pressure in a timely manner without sacrificing a high-speed slide elevating movement, thereby improving product accuracy and productivity. An object of the present invention is to provide a servo press control device that can be improved.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a vibration sensor for detecting vibration of a servo press body in a servo press control device for moving a slide up and down by using a servo motor as a drive source. And a frequency estimating unit that estimates and outputs a specific frequency and a maximum output value generated in the molding from the vibration detected by the vibration sensor,
A comparator which compares the data of the specific frequency and the maximum output value in the molding obtained by the calculation or trial hitting set in the control device in advance with the output of the frequency estimating unit, and outputs a signal when they match, and a servo motor Input the slide position and speed information calculated from the output of the encoder provided in the bottom dead center discriminator that discriminates this and outputs a signal of the bottom dead center position; In addition to controlling the molding pressure in the press molding area obtained from the output of the above, the servo motor is controlled so that the slide moves at high speed in the non-press molding area.

[0006]

1 to 5 show an embodiment of a servo press control device according to the present invention. FIG. 1 shows a basic configuration of the present invention, FIG. 2 is a block diagram showing a detailed configuration of a control device 1 for controlling the servo press body 7 in FIG. 1, and FIGS. It is a drawing for explaining details.

In FIG. 1, a servo press body 7 moves up and down a slide 11 via a speed reduction mechanism 8 by a servo motor 9 which can be numerically controlled, and a slide 11 and a bolster 12
Then, a mold (not shown) is attached, and the material supplied to the mold is pressed. The servo motor 9 is controlled by the output of the control device 1, and the position and speed of the slide 11 are controlled by the output signal of the encoder 10 directly connected to the servo motor 9.
To be obtained. The vibration sensor 13 provided on the servo press body 7 supplies an output signal, which has detected the vibration of the servo press body 7, to the control device 1. The control device 1 includes a data display unit 2, a data input unit 3, a numerical control device 4, a servo amplifier 5, and an amplifier 6, which will be described in detail with reference to FIG.

In FIG. 2, required data is input to a data input unit 3. The vibration output including the wide-range frequency detected by the vibration sensor 13 corresponds to the molding start point P1 shown in FIG.
Tens of meters specific to molding that do not occur in slide elevating movement
s to several hundred ms vibration and vibration of slide elevating movement are included. The vibration caused by molding affects the position deviation and torque command. The filter 21 allows only the vicinity of the frequency fa shown in FIG. The frequency fa is specific data of a specific frequency and an output level which are different depending on the thickness of the material, the processing speed, the material, the processing method, and the like in molding. The frequency estimating unit 22 estimates vibration frequency data (fa) and its maximum output value from the transition of the unique data. Depending on the situation, the frequency fa may be several points.

The comparator 23 compares the vibration frequency of the frequency fa and the maximum output value with the pre-calculated or trial-formed molding data stored in the machining data 18 and 19,
When it is determined that the frequency matches the molding frequency fa, the output signal is input to the selector 28 assuming that the slide has reached the molding start point. When the bottom dead center determination 25 determines the bottom dead center from the slide position and the slide speed of the position and speed information 24, the bottom dead center output is input to the selector 28. The input maximum output current 26 of the servo amplifier is calculated by the calculation unit 30 in consideration of the conditions of the machine specification 38 to determine the machine drive torque 27 which is the maximum motor generated torque. Based on the input molding pressure 29, the calculation unit 30 similarly calculates the motor generated torque during molding to determine the molding torque 31. The mechanical drive torque 27 and the forming torque 31 are also input to the selector 28.

When the comparator 23 does not determine the molding start point, the selector 28 selects the mechanical drive torque 27 and inputs an output that has determined the frequency fa.
Select Thereafter, when the bottom dead center output is input from the bottom dead center determination 25, the mechanical drive torque 27 is selected again. The torque values 27 and 31 selected by the selector 28 are input to a torque limiter 37 to control the motor generated torque of the servo motor 9.

FIG. 3 shows the motor speed and torque command of the servo motor 9 controlled according to the present invention. Slide 11
Falls from the top dead center Y1 to the bottom dead center Y5 and reaches the bottom dead center Y5, from Y1 to Y4 by the mechanical drive torque 27 under the position / speed control by the command of the position command generating unit 34. , From Y1 to Y2, the speed is increased by the torque command value Ta2; from Y2 to Y3, the speed is decreased at a constant (maximum) speed by the torque command value Tb; The torque limiter 37 to which the torque 31 is input operates, and the torque command value Tp
It reaches the bottom dead center Y5 while being restricted to the molding torque of 2. The mechanical drive torque 27 is again selected based on the output of the bottom dead center determination 25 that has determined that the bottom dead center has been reached, and the selector 28 and the torque limiter 37 to which the output has been input interlock, and the servo motor 9 is driven by the torque command value −Ta2 or the like. The reverse rotation is controlled within the maximum current range, and the slide 11 moves up at a high speed from Y6 to the top dead center.

[0012]

As is apparent from the above description, according to the present invention, the molding start point is determined from the frequency characteristics of the vibration obtained by the vibration sensor, and the bottom dead center is determined from the slide position and speed information. Then, the servomotor output was controlled to the required molding torque so that the required molding pressure was obtained in the press molding area during this time, and the servomotor torque was controlled to move the slide at high speed in other non-press molding areas. Good molding can be performed with high accuracy and productivity can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a basic system configuration in an embodiment of the present invention.

FIG. 2 is a block diagram of a control device.

FIG. 3 is a diagram showing the relationship between a motor speed and a torque command and time during a descending stroke.

FIG. 4 is also a diagram showing the positional deviation of the molding start point, the torque command, the output of the vibration sensor and the time.

FIG. 5 is a frequency characteristic diagram of the output of the vibration sensor and the frequency.

[Explanation of symbols]

1 is a control device, 2 is a data display unit, 3 is a data input unit,
4 is a numerical controller, 5 is a servo amplifier, 6 is an amplifier, 7
Is a servo press body, 8 is a speed reduction mechanism, 9 is a servo motor, 10 is an encoder, 11 is a slide, 12 is a bolster, 13 is a vibration sensor, 18, 19 are machining data, 21
Is a filter, 22 is a frequency estimator, 23 is a comparator, 24
Is position and speed information, 25 is bottom dead center determination, 26 is servo amplifier maximum current, 27 is mechanical drive torque, 28 is a selector, 29 is a molding pressure, 30 is a calculation unit, 31 is a molding torque, and 34 is a position command generation. , 35 is a position control unit, 36 is a speed control unit, 37 is a torque limiter, 38 is a machine specification,
It is.

Claims (1)

[Claims] An apparatus for controlling a servo press, which moves a slide up and down by using a servo motor as a drive source, comprises a vibration sensor for detecting a vibration of the servo press body, and a vibration generated by the vibration sensor, the identification being generated at the time of molding. A frequency estimating unit for estimating and outputting a frequency and a maximum output value, and data of a specific frequency and a maximum output value in the shaping set in advance in the control device, and comparing the output of the frequency estimating unit with each other. And a bottom dead center discriminator that inputs slide position and speed information calculated from the output of an encoder provided in the servo motor, discriminates the information, and outputs a signal of the bottom dead center position. In addition, while controlling the molding pressure in the press molding area obtained from the output of the comparator and the bottom dead center discrimination, the slide speed is high in the non-press molding area. Servo press control device and controls the servo motor so as to dynamic.