WO2018189580A1 - Electric press, control method, and program - Google Patents

Abstract

Provided is an electric press with which pressurizing work can be carried out with an appropriate load on a workpiece while preventing extension of tact time. An electric press has an electric motor, a motor driver that supplies driving electric power to the electric motor, a ram that performs pressurizing work on a workpiece through the motive power of the electric motor, and a target load value storage unit that stores a target load value of the ram, and the electric press is provided with a first estimation unit that estimates the distance by which the ram overshoots after the supply of a drive command pulse signal inputted to the motor driver has been stopped, a second estimation unit that estimates the distance by which the ram moves until reaching the target load value, and a drive command pulse signal stopping unit that stops the supply of the drive command pulse signal at the point in time when the value estimated by the first estimation unit has reached the value estimated by the second estimation unit.

Description

Electric press, control method and program

The present invention relates to an electric press, a control method, and a program.

Generally, in an electric press, there are drive modes such as “constant speed / load stop” and “constant speed / differential stop”. In such a drive mode, a phenomenon may occur in which the ram inherently overshoots from the position where it should stop. This overshoot amount generally depends on the driving speed of the ram, and it is known that the overshoot amount increases as the driving speed increases.

In order to reduce such overshoot phenomenon, "Deceleration load factor" (control to pressurize at a low drive speed when the set load factor is reached for the target load) or "Reference There is prepared a method such as “stop position” (control by which the ram will stop and then pressurize at a very low speed from that position).

Further, in order to reduce the amount of overshoot, a method of adaptively changing the drive speed based on the difference between the target load and the current load or the increasing tendency of the load is also disclosed (for example, patents). Reference 1).

Japanese Patent No. 3076755

However, the technique disclosed in Patent Document 1 is to reduce the overshoot by decreasing the drive speed as it approaches the target, and the processing time becomes longer by decreasing the drive speed. There was a problem that the tact time could not be shortened.

In general, when the servo motor is pulse-controlled with a motor driver, when the supply of the command pulse signal input to the motor driver is stopped, the command pulse position that the motor driver has at that time and the position indicated by the motor encoder , The distance corresponding to the so-called “accumulated pulse” moves from the position where the supply of the command pulse signal is stopped and stops. From such a phenomenon, it is considered that it is possible to prevent the overshoot phenomenon from occurring if the “accumulated pulse” is eliminated at the same time when the supply of the command pulse signal is stopped.

Certainly, if the “accumulation pulse” is eliminated, the final stop position will be the position where the supply of the command pulse signal is stopped. , Behaves like returning and stopping.

Therefore, the behavior as described above is inappropriate as the operation of a press that is pressure driven as a machining operation. In fact, once bending or press-fitting and overshooting and pushing the workpiece, there is no point in returning to an appropriate position, and the load value when stopped is the maximum There was a problem that it was not a value but a value of insufficient load.

Accordingly, the present invention has been made in view of the above-described problems, and provides an electric press, a control method, and a program capable of performing pressurization work on a work with an appropriate load while preventing an increase in tact time. To do.

Form 1; One or more embodiments of the present invention include an electric motor, a motor driver that supplies driving electric power to the electric motor, a ram that pressurizes a work with the power of the electric motor, A target load value storage unit that stores a target load value of the ram, and after the supply of a drive command pulse signal input to the motor driver is stopped, a first distance that the ram overshoots is estimated The estimation unit, the second estimation unit for estimating the travel distance of the ram until the target load value is reached, and the estimation value by the first estimation unit become the estimation value by the second estimation unit. There is proposed an electric press comprising a drive command pulse signal stop unit that stops supply of the drive command pulse signal at a time point.

Mode 2 One or more embodiments of the present invention include a speed detection unit that detects the speed of the ram, and the first estimation unit sets a distance over which the ram overshoots by D _v [mm]. An electric press characterized by estimating the distance over which the ram overshoots based on the equation (1) when the speed dependence coefficient is K _v [sec] and the speed of the ram is V [mm / s]. Has proposed.

Mode 3; One or more embodiments of the present invention include a speed detection unit that detects the speed of the ram and a load value detection unit that detects a load value applied to the ram, and the first estimation The section includes a distance over which the ram overshoots _Dvf [mm], a speed dependence coefficient _Kv [sec], a speed of the ram V [mm / s], and a load dependence coefficient _Kf [sec / N]. The electric press is characterized in that the distance over which the ram overshoots is estimated based on Equation 2 when the load value is F [N].

Mode 4: One or more embodiments of the present invention include a position detection unit that detects the position of the ram, a load value detection unit that detects a load value applied to the ram, and the position and position of the ram. A data string storage unit that stores a data string associated with a load value applied to the ram; a load gradient value calculation unit that calculates a load gradient value based on the data string stored in the data string storage unit; And the second estimation unit is configured to determine the target load value based on the current load value applied to the ram detected by the load value detection unit and the load gradient value calculated by the load gradient value calculation unit. The electric press characterized by estimating the moving distance of the said ram until the load value detected by the said load value detection part arrives at the said target load value memorize | stored in the memory | storage part is proposed.

Mode 5: One or more embodiments of the present invention are characterized in that the load gradient value calculation unit calculates a first-order differential value of a load value related to a change in the position of the ram as the load gradient value. Proposes an electric press.

Embodiment 6: One or more embodiments of the present invention propose an electric press characterized in that the load inclination value calculation unit calculates the load inclination value by regression calculation.

Mode 7: In one or more embodiments of the present invention, the load gradient value calculation unit further calculates a second-order differential value of a load value related to a change in the position of the ram, and the second estimation unit , The target load value is F _t [N], the current load value is F ₀ [N], the load inclination value is S _f [N / mm], and the second-order differential value of the load value is S _sf [N / mm2], and when the moving distance is _Dt [mm], an electric press characterized by estimating _Dt based on Equation 3 is proposed.

Mode 8: In one or more embodiments of the present invention, when the ram is once stopped, the ram is further moved to a predetermined setting position, and a work is pressurized. The driving command pulse signal corresponding to the distance to the set position is input to the motor driver based on the position with respect to the distance overshooting the ram estimated by the first estimation unit. Proposing a press.

Mode 9: One or more embodiments of the present invention include an electric motor, a motor driver that supplies driving electric power to the electric motor, and a ram that pressurizes the workpiece by the power of the electric motor. An electric press comprising: a load value detection unit that detects a load value applied to the ram; and a position detection unit that detects the position of the ram, and supplies a drive command pulse signal input to the motor driver A first estimation unit that estimates the distance over which the ram overshoots, and a data string storage unit that stores a data string in which the position of the ram and the load value applied to the ram at the position are linked A load gradient value calculation unit that calculates a load gradient value based on the data sequence stored in the data string storage unit, a target load gradient value storage unit that stores a target load gradient value, The movement of the ram until the target load inclination value is reached based on the current load inclination value calculated by the load inclination value calculation section and the target load inclination value storage section but stored in the target load inclination value storage section A third estimator for estimating a distance; and a drive command pulse signal stop for stopping the supply of the drive command pulse signal when an estimated value by the first estimator becomes an estimated value by the third estimator And an electric press characterized by comprising a part.

Mode 10: In one or more embodiments of the present invention, the load gradient value calculation unit calculates the load gradient value by a first-order differential value or a regression calculation of a load value related to a change in the position of the ram. The second estimation value of the load value related to the change in the position of the ram is calculated, and the third estimation unit calculates the target load inclination value by S _ft [N / mm], the first-order differential value or the regression calculation. The calculated load inclination value (current load inclination value) is S _f0 [N / mm], the second-order differential value of the load value is S _sf [N / mm2], and the moving distance until the target load inclination value is reached is D An electric press characterized by estimating D _t based on Equation 4 when _t [mm] is proposed.

Mode 11: One or more embodiments of the present invention include an electric motor, a motor driver that supplies driving electric power to the electric motor, a ram that pressurizes the workpiece with the power of the electric motor, A control method in an electric press having a target load value storage unit that stores a target load value of the ram, a first estimation unit, a second estimation unit, and a drive command pulse signal stop unit, A first step of estimating a distance over which the ram overshoots after the first estimation unit stops supplying the drive command pulse signal input to the motor driver, and the second estimation unit includes the target A second step of estimating the travel distance of the ram until the load value is reached, and the estimated value by the first estimating unit of the driving command pulse signal stop unit becomes an estimated value by the second estimating unit. The Proposes a control method characterized by comprising: a third step of stopping the supply of the drive command pulse signal at point a.

Mode 12: One or more embodiments of the present invention include an electric motor, a motor driver that supplies driving electric power to the electric motor, a ram that pressurizes the workpiece with the power of the electric motor, A computer executes a control method in an electric press having a target load value storage unit that stores a target load value of the ram, a first estimation unit, a second estimation unit, and a drive command pulse signal stop unit. A first step of estimating a distance that the ram overshoots after the first estimation unit stops supplying a drive command pulse signal input to the motor driver; and A second step of estimating the ram travel distance until the target load value is reached, and the drive command pulse signal stop unit is estimated by the first estimation unit. Value is proposed a program for executing the third step, to the computer to stop the supply of the drive command pulse signal when it becomes the estimated value by the second estimator.

According to one or more embodiments of the present invention, there is an effect that a pressurization operation can be performed with an appropriate load on a workpiece while preventing an increase in tact time.

It is a figure which shows the structure of the electric press which concerns on the 1st Embodiment of this invention.

It is a figure which shows the electric constitution of the electric press which concerns on the 1st Embodiment of this invention.

It is a figure which shows the electrical constitution of the central processing unit which concerns on the 1st Embodiment of this invention.

It is a figure which shows the electrical structure of the drive command pulse signal stop part which concerns on the 1st Embodiment of this invention.

It is a figure which shows the process of the electric press which concerns on the 1st Embodiment of this invention.

It is a figure which shows the relationship with the distance from the time of a drive command pulse signal stopping to a ram stop, when changing the speed V as a parameter in the no-load state which concerns on the 1st Embodiment of this invention.

It is a figure which shows the electrical constitution of the central processing unit which concerns on the 2nd Embodiment of this invention.

It is a figure which shows the process of the electric press which concerns on the 2nd Embodiment of this invention.

It is a figure which shows the electric constitution of the electric press which concerns on the 3rd Embodiment of this invention.

It is a figure which shows the electrical constitution of the central processing unit which concerns on the 3rd Embodiment of this invention.

It is a figure which shows the process of the electric press which concerns on the 3rd Embodiment of this invention.

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

<Structure of electric press>
The structure of the electric press according to this embodiment will be described with reference to FIG.

As shown in FIG. 1, an electric press 100 according to the present embodiment includes a press ram 1 that applies a desired pressure to a workpiece W (processing object) by an elevating operation, and an elevating operation (straight line) on the ram 1. And a ball screw 2 that gives movement), and these are provided in the press body 3. A servo motor 4 such as an AC servo motor serving as a drive source is also housed in a head frame body of a casing 5 connected to the press body 3. Then, the drive of the servo motor 4 is transmitted to the ball screw 2 via a pulley and a belt.

The ram 1 is formed in a cylindrical body as shown in FIG. Specifically, a hollow portion is formed along the axial direction inside a cylindrical main body 1a, and the screw shaft 2a of the ball screw 2 can be inserted into the hollow portion. It has become. Further, a nut body 2b of the ball screw 2 is fixed to an end portion in the axial direction of the cylindrical main body 1a of the ram 1.

The strain column 9 is configured to be freely mounted at the distal end portion of the cylindrical main body 1a. In actuality, the strain column 9 abuts against the workpiece W and appropriately applies pressure. . In addition, the strain column 9 is configured so that a strain gauge can be attached, and the pressure applied to the workpiece W can be detected by the strain gauge.

A cylindrical guide 6 is provided so as to wrap the outer peripheral side surface of the cylindrical main body 1a. The cylindrical guide 6 is fixed in the casing 5, and the ram 1 can be moved up and down along the cylindrical guide 6.

<Electric configuration of electric press>
As shown in FIG. 2, the electric press 100 according to the present embodiment includes a servo motor driver 13, an encoder 14, a CPU (Central Processing Unit) 20, a control program storage unit 21, a display unit 22, and an operation. A unit 23, a temporary storage unit 24, a target load value storage unit 25, a data string storage unit 26, a circuit unit 27, a drive command pulse generation unit 28, and an encoder position counter 29 are configured.

The control program storage unit 21 stores a control program for the CPU (Central Processing Unit) 20 to control the operation and processing of the entire electric press 100. For example, in the present embodiment, the overshoot distance for estimating the distance over which the ram 1 overshoots after stopping the supply of a drive command pulse signal input to a servo motor driver 13 described later as well as the main program relating to the press work. At the time when the estimated value by the ram moving distance estimation program module becomes the estimated value by the ram moving distance estimation program module, the ram movement distance estimation program module that estimates the distance of the ram 1 until the target load value is reached, or the overshoot distance estimation program module A drive command pulse signal supply stop program module for stopping the supply of the drive command pulse signal is stored. The display unit 22 is a display device that displays various types of information. In the present embodiment, information such as the program number, the pressurizing condition, the number of work pieces to be processed is displayed.

The operation unit 23 includes a touch panel, a tact switch, and the like for setting the pressurizing condition. The temporary storage unit 24 stores temporary data. The target load value storage unit 25 stores the target load value of the ram 1. The data string storage unit 26 stores the position information obtained from the encoder position counter 29 and the load values detected in the strain column 9 and the circuit unit 27 in association with each other.

The circuit unit 27 amplifies a signal with respect to a resistance change of a strain gauge attached to the strain column 9, converts an analog signal into a digital signal by A / D conversion processing, and then outputs the analog signal to a CPU (central processing unit) 20. To do. The CPU (central processing unit) 20 detects the load value from the digital signal input from the circuit unit 27.

The drive command pulse generator 28 generates a desired drive command pulse based on a command from a CPU (Central Processing Unit) 20 and outputs it to the servo motor driver 13 via a drive command pulse signal stop unit described later. To do. The encoder 14 is used to detect the position of the ram 1 and is connected to the servo motor 4. The encoder position counter 29 counts up the pulse signal from the encoder 14. The CPU (central processing unit) 20 detects the position of the ram 1 from the count value of the encoder 14.

<Electrical configuration of central processing unit>
As shown in FIG. 3, the central processing unit 20 according to the present embodiment includes a speed detection unit 30, a first estimation unit 31, a load gradient value calculation unit 33, a second estimation unit 34, and a drive. A command pulse signal stop unit 35 is included.

The speed detection unit 30 detects the speed of the ram 1 based on an input signal from the encoder position counter 29 and a timer value (not shown), and outputs the detected speed to the first estimation unit 31.

The first estimation unit 31 estimates the distance that the ram 1 overshoots after the supply of the drive command pulse signal input to the servo motor driver 13 is stopped.

Here, when the load (ram 1 in this embodiment) is driven using the servo motor 4, the motor rotation angle per pulse of the drive command pulse signal from the servo motor driver 13 depends on the characteristics of the servo motor 4. By determining, the moving distance of the load due to the rotation of the servo motor 4 is determined. However, during the driving of the load, in fact, a difference (error) between the instructed position and the current position occurs, and the load moves even when the drive command pulse signal is stopped, so-called Overshoot will occur. Hereinafter, the amount of overshoot will be referred to as “a droop pulse amount” as appropriate. The first estimation unit 31 estimates the amount of accumulated pulses.

Specifically, the amount of movement of the ram 1 due to overshoot (the amount of accumulated pulses) has an element proportional to the speed and an element proportional to the load. Therefore, the accumulated pulse amount is represented by D _vf [mm], which depends on the speed. When the coefficient is K _v [sec], the speed of the ram 1 is V [mm / s], the load dependence coefficient is K _f [sec / N], and the load value is F [N], Estimate the amount of drooping pulses.

Here, the speed dependence coefficient K _v is a coefficient droop pulse amount that is proportional to the speed, load dependence coefficient K _f is a coefficient of droop pulse amount generated by the load, this factor is also dependent on the speed. Therefore, the accumulated pulse amount is estimated as the sum of these. Incidentally, the speed dependence coefficient K _v and load dependency coefficient K _f will vary by the feed packs gain of the drive system and servo motor driver 13. Therefore, these count values are obtained by measurement in advance. Specifically, in the no-load state (load value F = 0), the speed V is changed as a parameter until the load (ram 1 in this embodiment) stops moving from when the command drive pulse signal stops. Measure distance. A specific example is shown in FIG. 6, the slope of the graph corresponds to the speed dependence coefficient K _v. As for the load dependence coefficient K _f , the same measurement as in the case of the measurement of the speed dependence coefficient K _v is performed when a load (ram 1 in this embodiment) is applied, and the term of K _v * V is excluded. The value can be obtained from the coefficient.

As described above, instead of calculating the accumulated pulse amount from the current speed and load value, the servo motor driver 13 grasps the accumulated pulse amount in the servo motor driver 13 and uses this to determine the CPU (central processing). In the case of having a function of transmitting to the device 20, the CPU (central processing unit) 20 may directly acquire the accumulated pulse amount in real time from the servo motor driver 13.

Further, in the equation 1, since the load dependency coefficient values of K _f is small, the influence of the term of the load values F droop pulses amount relative to D _vf can be said to be limited. Therefore, the amount of droop pulses may be simply calculated based on Equation 2 from D _v [mm], the speed dependency coefficient K _v [sec], and the speed of the ram 1 V (mm / s).

The load inclination value calculation unit 33 calculates the load inclination value based on the data string stored in the data string storage unit 26. The load inclination value calculation unit 33 calculates a first-order differential value of the load value related to the change in the position of the ram 1 as the load inclination value. Specifically, for example, when the load inclination value is S _f [N / mm], the load value is F [N], and the distance is D [mm], the load inclination value S _f [N / mm] is a number. 3 is calculated.

Moreover, the load inclination value calculation part 33 can also obtain | require a load inclination value by the linear regression calculation using a regression line. In this case, the load inclination value is S _f [N / mm], the position data series of the pressurizing part is (x1, x2,..., Xn), and the load data series is (y1, y2,...). , Yn), the load inclination value S _f [N / mm] is calculated based on Equation 4.

The second estimation unit 34 estimates the moving distance of the ram 1 until the target load value is reached. Specifically, the target load value storage unit 25 stores the load value applied to the current ram 1 detected by the circuit unit 27 (load value detection unit) and the load gradient value calculated by the load gradient value calculation unit 33. The moving distance of the ram 1 until the load value detected by the circuit unit 27 (load value detection unit) reaches the stored target load value is estimated. In other words, the current load value in the no-load state is F ₀ [N], the load inclination value calculated by the load inclination value calculation unit 33 is S _f [N / mm], and the calculated travel distance of the ram 1 is D [mm]. ], The relationship of Equation 5 is obtained.

In Equation 5, when the target load value is F _t [N] and the ram movement distance until reaching the target load value F _t is D _t , Equation 6 is obtained. Here, when Equation 6 is transformed, Equation 7 is obtained to obtain the ram movement distance D _t until the target load value F _t is reached. Therefore, if the target load value F _t [N], the current load value F ₀ [N], and the load gradient value S _f [N / mm] are substituted into Equation 7, the target load value F _t is reached. You can obtain the moving distance D _t of the ram 1 to.

In the above description, the method of obtaining the moving distance D _t of the ram 1 until the target load value F _t is reached is illustrated as a first-order approximation from the load inclination value S _f [N / mm]. using second-order differential value with respect to the distance, as a secondary approximation, it is also possible to obtain the moving distance D _t of the ram 1 to reach the target load value F _t.

Specifically, when the second-order differential value S _sf [N / mm ² ] of the load value is represented by _Equation 8, the load value F is represented by Equation 9. Here, in the equation 9, a target load value F _t the load value F, if the distance D and the moving distance D _t of the ram 1 to reach the target load value F _t, is as few 10. By transforming this number 10, as in equation 11, as a quadratic equation relating D _t, solving this, as shown in Equation 12, it can be obtained D _t.

The drive command pulse signal stop unit 35 is configured until the estimated value (the accumulated pulse amount (distance over which the ram 1 is overshooted)) by the first estimating unit 31 reaches the estimated value (the target load value) by the second estimating unit 34. The supply of the drive command pulse signal is stopped at the point of time when the ram 1 travel distance is reached.

The specific configuration of the drive command pulse signal stop unit 35 includes, for example, a comparison unit 36, a switch element SW, and a resistor R as shown in FIG. The comparison unit 36 includes the amount of accumulated pulses (distance over which the ram 1 overshoots) obtained from the first estimation unit 31 and the travel distance of the ram 1 until reaching the target load value obtained from the second estimation unit 34. And the switch element SW is closed when the accumulated pulse amount (distance over which the ram 1 overshoots) reaches the movement distance of the ram 1 until the target load value is reached. When the switch element SW is in the closed state, the drive command pulse signal input terminal of the servo motor driver 13 is set to the “Low” level, so that the power supplied to the servo motor 4 by the servo motor driver 13 is turned off. As the switch element SW, a transistor or FET (Field                 effect transistors) and the like can be used. Further, instead of the resistor R, a Schottky diode having a small Vf may be used.

<Electric press processing>
The process of the electric press 100 according to the present embodiment will be described with reference to FIG.

First, the CPU (central processing unit) 20 reads the target load value from the target load value storage unit 25 and stores it in the temporary storage unit 24 (step S101). The CPU (Central Processing Unit) 20 generates a drive command pulse in the drive command pulse generator 28 based on the target load value stored in the temporary storage unit 24, and sends the generated drive command pulse signal to the servo motor driver 13. Output (step S102).

Next, the CPU (central processing unit) 20 compares the target load value read from the temporary storage unit 24 with the current load value applied to the current ram 1 detected by the load value detection unit (circuit unit 27), and sets the target load value. It is determined whether or not the difference value between the load value and the current load value is equal to or less than a predetermined value (step S103). If it is determined as a result of the determination that the difference value between the target load value and the current load value is not equal to or less than a predetermined value (“No” in step S103), the process returns to step S102. In step S103, it is determined whether or not the difference value between the target load value and the current load value is equal to or smaller than a predetermined specified value from the time when the target load value is approached to some extent. As the specified value, for example, it is considered that about 5% of the maximum pressure is appropriate.

As a result of the determination, when it is determined that the difference value between the target load value and the current load value is equal to or less than a predetermined specified value (“Yes” in step S103), the first estimation unit 31 is activated, The accumulation amount of the drive command pulse signal is detected from the current speed and the load value (step S104).

Next, the load gradient value is calculated by the load gradient value calculation unit 33 (step S105), the second estimation unit 34 is activated, and the current ram 1 detected by the load value detection unit (circuit unit 27) is applied. Based on the load value and the load gradient value calculated by the load gradient value calculation unit 33, the current load value detected by the load value detection unit (circuit unit 27) to the target load value stored in the target load value storage unit 25. Is estimated (step S106).

Then, the drive command pulse signal stop unit 35 determines whether the accumulation amount of the drive command pulse signal corresponding to the overshoot distance detected by the first estimation unit 31 matches the movement distance calculated by the second estimation unit 34. If it is determined (step S107) and it is determined that they match (“Yes” in step S107), output of the drive command pulse is stopped (step S108). On the other hand, when the drive command pulse signal stop unit 35 does not match the travel distance calculated by the second estimation unit 34 with the amount of accumulation of the drive command pulse signal corresponding to the overshoot distance detected by the first estimation unit 31. If it is determined (“No” in step S107), the process returns to step S102.

<Operation and effect of this embodiment>
According to the electric press according to the present embodiment, the first estimation unit 31 that estimates the distance that the ram 1 overshoots after the supply of the drive command pulse signal input to the servo motor driver 13 is stopped, and the target load A second estimator 34 for estimating the travel distance of the ram 1 until the value is reached, and the drive command pulse signal when the estimated value by the first estimator 31 becomes the estimated value by the second estimator 34. Since the drive command pulse signal stop unit 35 for stopping the supply of the workpiece is provided, it is possible to perform the pressurizing operation with an appropriate load on the workpiece while preventing the tact time from being extended.

The first estimation unit 31 also includes a distance D _vf [mm] over which the ram 1 overshoots, a speed dependence coefficient K _v [sec], a speed V [mm / s] of the ram 1 and a load dependence coefficient K _f [sec. / N] and the distance over which the ram 1 overshoots (accumulated pulse amount) is estimated by a relational expression using the load value F [N] as parameters, the distance over which the ram 1 overshoots accurately by a simple calculation process. (The amount of accumulated pulses) can be estimated.

Further, the first estimating unit 31 uses a relational expression in which the distance D _v [mm] over which the ram 1 overshoots, the speed dependency coefficient K _v [sec], and the speed V [mm / s] of the ram 1 are used as parameters. The distance over which 1 overshoots (the amount of accumulated pulses) can be estimated by a further simplified calculation formula.

Furthermore, the second estimation unit 34 sets the target load value F _t [N], the current load value F ₀ [N], the load gradient value S _f [N / mm], and the second-order differential value S _sf [ N / mm2] and the moving distance D _t [mm] as parameters, the current load value detected by the load value detection unit (circuit unit 27) to the target load value stored in the target load value storage unit 25 Estimate the travel distance of the ram 1 until it reaches. Therefore, the movement distance of the ram 1 until the current load value reaches the target load value can be accurately estimated by a simple calculation process.

<Second Embodiment>
The electric press 110 according to the present embodiment will be described with reference to FIGS. The electric press 110 according to the present embodiment relates to a two-stage drive method in which the press work is performed by temporarily stopping at a set load value and moving the ram 1 by a specified distance therefrom.

<Electrical configuration of central processing unit>
As shown in FIG. 7, the central processing unit 20A according to the present embodiment includes a speed detection unit 30, a first estimation unit 41, a load gradient value calculation unit 33, a second estimation unit 44, and a drive. And a command pulse signal stop unit 45. In addition, about the component which attaches | subjects the same code | symbol as 1st Embodiment, since it has the same function, the detailed description is abbreviate | omitted.

The first estimating unit 41 determines the distance (the amount of accumulated pulses) over which the ram 1 overshoots after stopping the supply of the drive command pulse signal input to the servo motor driver 13 for the first stage drive process. presume. Further, the first estimation unit 41 does not actually wait for the end of driving of the ram 1 after the drive command pulse signal stop unit 45 stops supplying the drive command pulse signal in the first stage drive process. A drive command pulse signal corresponding to the distance to the target position is further input to the servo motor driver 13 based on the position corresponding to the distance (accumulated pulse amount) over which the ram 1 estimated in the stage driving process is overshooted. Then, after the supply of the input drive command pulse signal is stopped, the distance over which the ram 1 overshoots (the amount of accumulated pulses) is estimated. Note that the method for estimating the overshoot distance is the same as in the first embodiment.

The second estimation unit 44 estimates the distance of the ram 1 until the target load value is reached in the first stage driving process. Further, the second estimation unit 44 does not actually wait for the end of driving of the ram 1 after the drive command pulse signal stop unit 45 stops supplying the drive command pulse signal in the first stage drive process. In the driving process at the stage, the distance of the ram 1 until the target load value is reached is estimated. Note that the method of estimating the distance of the ram 1 until the target load value is reached is the same as in the first embodiment.

The drive command pulse signal stop unit 45 is configured such that, in the first-stage driving process, the estimated value by the first estimating unit 41 (the amount of accumulated pulses (the distance over which the ram 1 overshoots)) is the estimated value by the second estimating unit 44. The supply of the drive command pulse signal is stopped at the point of time (the travel distance of the ram 1 until the target load value is reached). Further, in the second stage driving process, the estimated value (the amount of accumulated pulses (distance over which ram 1 overshoots)) by the first estimating unit 41 reaches the estimated value (target load value) by the second estimating unit 44. The supply of the drive command pulse signal is stopped at the time when the ram 1 travel distance is reached. The configuration of the drive command pulse signal stop unit 45 is the same as that of the first embodiment.

<Electric press processing>
The process of the electric press which concerns on this embodiment is demonstrated using FIG.

First, the CPU (central processing unit) 20A reads the target load value from the target load value storage unit 25 and stores it in the temporary storage unit 24 as the first-stage driving process (step S201). The CPU (Central Processing Unit) 20A generates a drive command pulse in the drive command pulse generator 28 based on the target load value stored in the temporary storage unit 24, and sends the generated drive command pulse signal to the servo motor driver 13. Output (step S202).

Next, the CPU (Central Processing Unit) 20A compares the target load value read from the temporary storage unit 24 with the current load value applied to the current ram 1 detected by the load value detection unit (circuit unit 27), and sets the target load value. It is determined whether or not the difference value between the load value and the current load value is equal to or less than a predetermined value (step S203). If it is determined as a result of the determination that the difference value between the target load value and the current load value is not equal to or less than a predetermined value (“No” in step S203), the process returns to step S202. In step S203, it is determined whether or not the difference value between the target load value and the current load value is equal to or less than a predetermined specified value from the time when the target load value is approached to some extent. As the specified value, for example, it is considered that about 5% of the maximum pressure is appropriate.

As a result of the determination, when it is determined that the difference value between the target load value and the current load value is equal to or less than a predetermined value (“Yes” in step S203), the first estimation unit 41 is activated, The accumulation amount of the drive command pulse signal is detected from the current speed and the load value (step S204).

Next, the load gradient value is calculated by the load gradient value calculation unit 33 (step S105), the second estimation unit 44 is activated, and the current ram 1 detected by the load value detection unit (circuit unit 27) is applied. Based on the load value and the load gradient value calculated by the load gradient value calculation unit 33, the current load value detected by the load value detection unit (circuit unit 27) to the target load value stored in the target load value storage unit 25. Is estimated (step S206).

Then, the drive command pulse signal stop unit 45 determines whether the accumulation amount of the drive command pulse signal corresponding to the overshoot distance detected by the first estimation unit 41 matches the movement distance calculated by the second estimation unit 44. If it is determined (step S207) and it is determined that they match (“Yes” in step S207), output of the drive command pulse is stopped (step S208). On the other hand, when the drive command pulse signal stop unit 45 does not match the moving distance calculated by the second estimation unit 44, the amount of accumulation of the drive command pulse signal corresponding to the overshoot distance detected by the first estimation unit 41 If it is determined (“No” in step S207), the process returns to step S202.

When the output of the drive command pulse is stopped, the CPU (central processing unit) 20A determines whether the series of processing from step S201 to step S208 is the first stage driving process or the second stage driving process. If it is determined that the driving process is the first stage (“No” in step S209), the process returns to step S201, and a series of processes from step S201 to step S208 is executed. On the other hand, if it is determined that the driving process is in the second stage (“Yes” in step S209), the process ends.

<Operation and effect of this embodiment>
According to the electric press according to the present embodiment, the distance over which the ram 1 overshoots after the supply of the drive command pulse signal input to the servo motor driver 13 is stopped even in the pressurization operation by the two-stage drive method. A first estimation unit 41 for estimation, a second estimation unit 44 for estimating the travel distance of the ram 1 until the target load value is reached, and an estimation value by the first estimation unit 41 is a second estimation unit 44. A drive command pulse signal stop unit 45 that stops the supply of the drive command pulse signal at the time when the estimated value is reached, between the first stage drive process and the second stage drive process, Since there is no need to wait for the driving to actually end, it is possible to execute a pressurizing operation with an appropriate load on the workpiece while preventing an increase in tact time.

<Third Embodiment>
The electric press 120 according to the present embodiment will be described with reference to FIGS. 9 to 11. The electric press 120 according to the present embodiment relates to a so-called differential load stopping method in which the stopping process is performed when the load inclination exceeds the target load inclination value.

<Electric configuration of electric press>
As shown in FIG. 9, the electric press 120 according to the present embodiment includes a servo motor driver 13, an encoder 14, a CPU (Central Processing Unit) 20B, a control program storage unit 21, a display unit 22, and an operation. A unit 23, a temporary storage unit 24, a target load gradient value storage unit 25A, a data string storage unit 26, a circuit unit 27, a drive command pulse generation unit 28, and an encoder position counter 29 are included. In addition, about the component which attaches | subjects the same code | symbol as 1st Embodiment, since it has the same function, the detailed description is abbreviate | omitted.

The target load gradient value storage unit 25A stores a target load gradient value according to the present embodiment.

<Electrical configuration of central processing unit>
As shown in FIG. 10, the central processing unit 20B according to the present embodiment includes a speed detection unit 30, a first estimation unit 31, a load gradient value calculation unit 33, a third estimation unit 38, and a drive. And a command pulse signal stop unit 55. In addition, about the component which attaches | subjects the same code | symbol as 1st Embodiment and 2nd Embodiment, since it has the same function, the detailed description is abbreviate | omitted.

The third estimation unit 38 reaches the target load gradient value based on the current load gradient value calculated by the load gradient value calculation unit 33 and the target load gradient value stored in the target load gradient value storage unit 25A. The travel distance of the ram 1 is estimated.

Here, as shown below, the third estimation unit 38 estimates the moving distance of the ram 1 until the target load inclination value is reached.

First, S _f is the load gradient value [N / mm], S _f0 is the current load gradient value [N / mm], D is the distance [mm], and S _sf is the second-order differential value of the load value [N / mm ² ]. Then, these become the relationship of Formula 13.

In Expression 13, the distance at which the target load slope value _{S ft} as _{D t,} which is solved for _{D t,} the number 14. Thus, the travel distance D _t of the ram 1 until the target load inclination value is reached is estimated.

Further, the second-order differential value S _sf of the load value can be obtained from the slope of the regression line in the same manner as the first-order differential value S _f of the load value. In this case, assuming that the position data series is (x1, x2,..., Xn) and the data series of the first-order partial value of the load is (y1, y2,..., Yn), the second floor of the load value. The differential value S _sf is calculated based on _Equation 15.

<Electric press processing>
The process of the electric press according to the present embodiment will be described with reference to FIG.

First, the CPU (central processing unit) 20B reads the target load gradient value from the target load gradient value storage unit 25A and stores it in the temporary storage unit 24 (step S301). The CPU (Central Processing Unit) 20B generates a drive command pulse in the drive command pulse generation unit 28 based on the target load inclination value stored in the temporary storage unit 24, and the generated drive command pulse signal is transmitted to the servo motor driver 13. (Step S302).

Next, the load gradient value calculation unit 33 calculates the current load gradient value (step S303). The CPU (central processing unit) 20 compares the target load inclination value read from the temporary storage unit 24 with the current load value calculated by the load inclination value calculation unit 33, and compares the target load inclination value with the current load inclination value. It is determined whether or not the difference value is equal to or less than a predetermined value (step S304). If it is determined that the difference value between the target load inclination value and the current load inclination value is larger than a predetermined value (“No” in step S304), the process returns to step S302.

As a result of the determination, when it is determined that the difference value between the target load inclination value and the current load inclination value is equal to or less than a predetermined value (“Yes” in step S304), the first estimation unit 31 is activated. Then, the accumulation amount of the drive command pulse signal is detected from the current speed and the load value (step S305).

Next, the third estimation unit 38 is activated, and the ram 1 until the load gradient value detected by the load gradient value calculation unit 33 reaches the target load gradient value stored in the target load gradient value storage unit 25A. The movement distance is estimated (step S306).

Then, until the drive command pulse signal stop unit 55 reaches the target load inclination value calculated by the third estimation unit 38, the amount of accumulation of the drive command pulse signal corresponding to the overshoot distance detected by the first estimation unit 31 is reached. Is determined (step S307). If it is determined that the distance is equal, the output of the drive command pulse is stopped (step S308). On the other hand, the drive command pulse signal stop unit 55 sets the amount of accumulation of the drive command pulse signal corresponding to the overshoot distance detected by the first estimation unit 31 to the shift target load slope value calculated by the third estimation unit 38. If it is determined that the moving distance does not match the actual moving distance (“No” in step S307), the process returns to step S302.

<Operation and effect of this embodiment>
According to the electric press according to the present embodiment, the first estimation unit 31 that estimates the distance over which the ram 1 overshoots after the supply of the drive command pulse signal input to the servo motor driver 13 is stopped, and the ram 1 And a data string storage unit 26 for storing a data string in which the load value applied to the ram 1 is linked at the position and a data string stored in the data string storage unit 26, and a load inclination value is calculated. Load gradient value calculation unit 33, target load gradient value storage unit 37 that stores the target load gradient value, and current load gradient value calculated by load gradient value calculation unit 33 and target load gradient value storage unit 37 Based on the target load inclination value, a third estimation unit 38 that estimates the movement distance of the ram 1 until the target load inclination value is reached, and the estimated value by the first estimation unit 31 is the third estimation unit 38. Guess by And the drive command pulse signal stop unit 55 that stops the supply of the drive command pulse signal when the value reaches the value, so that the estimated value by the first estimation unit 31 is the third value even when the differential load is stopped. By stopping the supply of the drive command pulse signal when the estimated value by the estimating unit 38 is reached, overshoot of the ram 1 can be prevented. Therefore, it is possible to perform the pressurizing operation with an appropriate load on the workpiece while preventing the tact time from being extended.

The third estimation unit 38, a target load slope value _{S ft} [N / mm], first order differential value or load tilt value calculated by regression calculation (current load gradient value) _{S f0} [N / mm] D _t is estimated based on a predetermined relational expression, where S _sf [N / mm2] is the second-order differential value of the load, and D _t [mm] is the moving distance until the target load inclination value is reached. Thus, the movement distance of the ram 1 up to the target load inclination value can be accurately estimated by a simple calculation process.

It is to be noted that the electric press of the present invention can be realized by recording the processing of the electric press on a computer system or a computer-readable recording medium, and reading and executing the program recorded on the recording medium. it can. The computer system or computer here includes an OS and hardware such as peripheral devices.

Further, the “computer system or computer” includes a homepage providing environment (or display environment) if a WWW (World Wide Web) system is used. The program may be transmitted from a computer system or computer storing the program in a storage device or the like to another computer system or computer via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.

Further, the program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system or the computer, what is called a difference file (difference program) may be sufficient.

As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiments, and includes designs and the like that do not depart from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1; Ram 1a; Cylindrical main body 2; Ball screw 2a; Screw shaft 2b; Nut body 3; Press main body 4; Electric motor 5: Casing 6; Cylindrical guide 9; CPU (Central Processing Unit)
21; control program storage unit 22; display unit 23; operation unit 24; temporary storage unit 25; target load value storage unit 25A; target load gradient value storage unit 26; data string storage unit 27; circuit unit 28; Unit 29; encoder position counter 30; speed detection unit 31; first estimation unit 33; load gradient value calculation unit 34; second estimation unit 35; drive command pulse signal stop unit 36; comparison unit 38; Unit 41; first estimation unit 42; second estimation unit 45; drive command pulse signal stop unit 55; drive command pulse signal stop unit 100; electric press

Claims (12)

1. An electric motor; a motor driver that supplies driving power to the electric motor; a ram that pressurizes a work by the power of the electric motor; and a target load value storage unit that stores a target load value of the ram. Have
   A first estimator for estimating a distance that the ram overshoots after stopping the supply of a drive command pulse signal input to the motor driver;
   A second estimating unit for estimating a moving distance of the ram until the target load value is reached;
   A drive command pulse signal stop unit that stops the supply of the drive command pulse signal when the estimated value by the first estimation unit becomes the estimated value by the second estimation unit;
   An electric press comprising:
2. Having a speed detector for detecting the speed of the ram;
   The first estimation unit includes:
   When the distance over which the ram overshoots is D _v [mm], the speed dependency coefficient is K _v [sec], and the speed of the ram is V [mm / s] The electric press according to claim 1, wherein a distance to be shot is estimated.
   
3. A speed detector for detecting the speed of the ram; and a load value detector for detecting a load value applied to the ram;
   The first estimation unit includes:
   The distance over which the ram overshoots is D _vf [mm], the speed dependence coefficient is K _v [sec], the speed of the ram is V [mm / s], the load dependence coefficient is K _f [sec / N], and the load 2. The electric press according to claim 1, wherein when the value is F [N], the distance over which the ram overshoots is estimated based on Equation (2).
   
4. A position detector for detecting the position of the ram;
   A load value detector for detecting a load value applied to the ram;
   A data string storage unit for storing a data string in which the position of the ram and the load value applied to the ram at the position are linked;
   A load inclination value calculation unit for calculating a load inclination value based on the data string stored in the data string storage unit;
   With
   The second estimation unit stores the target load value storage unit based on the current load value applied to the ram detected by the load value detection unit and the load gradient value calculated by the load gradient value calculation unit. 2. The electric press according to claim 1, wherein a movement distance of the ram until the load value detected by the load value detection unit reaches the stored target load value is estimated.
5. 5. The electric press according to claim 4, wherein the load inclination value calculation unit calculates a first-order differential value of the load value related to a change in the position of the ram as the load inclination value.
6. 5. The electric press according to claim 4, wherein the load inclination value calculation unit calculates the load inclination value by regression calculation.
7. The load inclination value calculation unit further calculates a second-order differential value of the load value related to the change in the position of the ram,
   The second estimation unit includes
   The target load value is F _t [N], the current load value is F ₀ [N], the load inclination value is S _f [N / mm], and the second-order differential value of the load value is S _sf [N / mm 2 The electric press according to any one of claims 4 to 6, wherein D _t is estimated based on Equation 3 when the moving distance is D _t [mm].
   
8. When the ram is temporarily stopped, and then the ram is further moved to a predetermined setting position to pressurize the workpiece, the first estimation unit estimates the 8. The drive command pulse signal corresponding to the distance to the set position is further input to the motor driver based on the position with respect to the distance over which the ram overshoots. The electric press as described.
9. An electric motor; a motor driver that supplies driving power to the electric motor; a ram that pressurizes the workpiece by the power of the electric motor; and a load value detector that detects a load value applied to the ram. A position detector for detecting the position of the ram, and an electric press comprising:
   A first estimator for estimating a distance that the ram overshoots after stopping the supply of a drive command pulse signal input to the motor driver;
   A data string storage unit for storing a data string in which the position of the ram and the load value applied to the ram at the position are linked;
   A load inclination value calculation unit for calculating a load inclination value based on the data string stored in the data string storage unit;
   A target load slope value storage unit for storing the target load slope value;
   The movement of the ram until the target load gradient value is reached based on the current load gradient value calculated by the load gradient value calculation unit and the target load gradient value stored in the target load gradient value storage unit A third estimator for estimating the distance;
   A drive command pulse signal stop unit that stops the supply of the drive command pulse signal when the estimated value by the first estimation unit becomes the estimated value by the third estimation unit;
   An electric press comprising:
10. The load inclination value calculation unit calculates the load inclination value by a first-order differential value or regression calculation of the load value related to the change in the ram position, and a second-order of the load value related to the change in the ram position. Calculate the differential value,
    The third estimation unit includes
    The target load gradient value is S _ft [N / mm], the first-order differential value or the load gradient value (current load gradient value) calculated by regression calculation is S _f0 [N / mm], and the second-order derivative of the load value The D _t is estimated based on the _equation (4) when the value is S _sf [N / mm 2] and the moving distance until the target load inclination value is D _t [mm]. The electric press according to 9.
    
11. An electric motor; a motor driver that supplies driving power to the electric motor; a ram that pressurizes a work by the power of the electric motor; and a target load value storage unit that stores a target load value of the ram. A control method in an electric press having a first estimation unit, a second estimation unit, and a drive command pulse signal stop unit,
    A first step of estimating a distance that the ram overshoots after the first estimation unit stops supplying a drive command pulse signal input to the motor driver;
    A second step in which the second estimation unit estimates a moving distance of the ram until the target load value is reached;
    A third step in which the drive command pulse signal stop unit stops the supply of the drive command pulse signal when the estimated value by the first estimating unit becomes the estimated value by the second estimating unit;
    A control method comprising:
12. An electric motor; a motor driver that supplies driving power to the electric motor; a ram that pressurizes a work by the power of the electric motor; and a target load value storage unit that stores a target load value of the ram. A program for causing a computer to execute a control method in an electric press having a first estimation unit, a second estimation unit, and a drive command pulse signal stop unit,
    A first step of estimating a distance that the ram overshoots after the first estimation unit stops supplying a drive command pulse signal input to the motor driver;
    A second step in which the second estimation unit estimates a moving distance of the ram until the target load value is reached;
    A third step in which the drive command pulse signal stop unit stops the supply of the drive command pulse signal when the estimated value by the first estimating unit becomes the estimated value by the second estimating unit;
    A program that causes a computer to execute.