JPH0457615A - Shear control device - Google Patents

Abstract

PURPOSE:To eliminate the effect of a delay time by providing a means for detecting the delay of deceleration timing detected with a deceleration means for timing for the change of the speed reference of a speed reference generation means from acceleration to deceleration, and another means for advancing generation timing for a deceleration instruction in an amount corresponding to the delay time of a shear. CONSTITUTION:Deceleration timing for a shear 1 is detected with a deceleration detector 9 on the basis of the actual speed of a shear 1. The detected deceleration timing and timing for speed reference changed from acceleration to deceleration, are compared and a delay time, t is detected with a computing element 10. Then, the timing for generating a deceleration instruction given from a deceleration point detector 6 to a speed reference generator 8 is advanced by the aforesaid delay time t, using a deceleration point compensation device 12. According to the aforesaid construction, the effect of the delay time can be properly eliminated without any increase in the capacity of an electric motor 2 for the shear 1.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a start-stop type flying shear connected to a metal rolling mill, and in particular to a shear adapted to correct deceleration timing. The present invention relates to a control device.

(Prior Art) This type of shear consists of an upper shear IA and IB, as shown in FIG. 2(a). Here, when the material M moves from left to right in the drawing, each cutting blade is accelerated as shown by the solid arrow in order to cut the material at the bottom dead center, and the cutting blades are accelerated as shown by the solid arrows to cut the material at or past the bottom dead center. However, the vehicle is decelerated from the set deceleration target position as shown by the broken line arrow. FIG. 2(b) is a time chart showing the relationship among the actual speed of the shear, the speed reference for speed control, and the current of the drive motor. In the figure, the actual speed of the shear is set at time t so that it reaches the set speed at the bottom dead center. The so-called time t after the bottom dead center, which is accelerated further and reaches or passes the bottom dead center
Even if a deceleration command is issued at time t2, deceleration is started at time t2, which is delayed by Δt.

Further, the speed reference indicates acceleration as a "positive" value and deceleration as a "negative" value, and is switched from "positive" to "negative" at time t1 when a deceleration command is given. On the other hand, the current of the shear drive motor is controlled according to this speed standard, but there is an unavoidable time delay in its rise and fall, and the current polarity is switched after detecting the zero point, so the actual speed of the shear is decelerated. Deceleration starts at time t2, which is delayed by Δt from time t1 when the command is given.

(Problem to be Solved by the Invention) The delay time Δt mentioned above is several tens of milliseconds [a+sec
] It is about . Therefore, if the shear is operated at low speed, the influence of this delay time Δt can be ignored. However, when the shear is operated at high speed, the ratio of the rotation angle due to the delay time Δt to the allowable deceleration angle, that is, the allowable rotation angle from the deceleration target position to the completion of deceleration, increases becomes impossible to ignore.

If the value obtained by subtracting the rotation angle due to the delay time Δt from the allowable deceleration angle is to be suppressed to a predetermined value or less, a motor with a large capacity must be used.

As a method of suppressing such an increase in the capacity of the electric motor, it is conceivable to output the deceleration command earlier by the delay time Δt, for example. However, since the actual delay time Δt varies depending on the speed at the time of the deceleration command, the motor current, etc., it has not been set too early in consideration of safety.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a shear control device that can reliably eliminate the influence of delay time without increasing the capacity of the electric motor.

[Structure of the invention]

(Means for Solving the Problems) The present invention generates a deceleration command when the cutting blade reaches a set deceleration target position, and also controls the shear according to a speed standard that switches from acceleration to deceleration when the deceleration command is generated. A control device for a shear that controls speed includes a speed detection means for detecting the actual speed of the shear, a deceleration detection means for detecting a deceleration timing of the shear based on the output of the speed detection means, and a speed reference generation means. delay time calculation means for detecting a delay time of the deceleration timing detected by the deceleration detection means with respect to the timing when the speed standard is changed from acceleration to deceleration; and deceleration for advancing the generation timing of the deceleration command by the delay time of the shear. It is equipped with a command correction means.

(Function) In this invention, the deceleration timing of the shear is detected based on the actual speed of the shear, and the delay time is detected by comparing this deceleration timing with the timing at which the speed reference is changed from acceleration to deceleration. Since the generation timing of the deceleration command is advanced by this delay time, the influence of the delay time can be reliably removed without increasing the capacity of the electric motor.

(Embodiment) FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In the figure, an electric motor 2 that drives a shear 1 is equipped with an electric motor control device 3. A speed detector 4 for detecting the speed of the shear and a position detector 5 for detecting the position of the cutting blade are coupled to the electric motor 2. Of these, the speed detector 4 is a speedometer generator, and the position detector 5 is a pulse transmitter. The position signal of the cutting blade detected by the position detector 5 is added as one input to a deceleration point detector 6 that detects that the cutting blade has reached the deceleration point.

Further, a deceleration target setting device 7 is provided to set a deceleration target position S after the bottom dead center of the shear, and its output is input to the deceleration point correction device 12. This deceleration point correction bag! 12
is the deceleration target position S.

The deceleration target position is obtained by subtracting the travel distance ΔS from the deceleration point detector 6, and this deceleration target position SD' is inputted to the other side of the deceleration point detector 6 and added. The deceleration point detector 6 outputs a deceleration command to be applied to the speed reference generator 8 when both human forces match. The speed reference generator 8 generates a speed reference VR proportional to the set speed V8 corresponding to the moving speed of the material M and provides it to the motor control device 3, and also reverses the polarity of this speed reference when a deceleration command is given. It is something that makes you On the other hand, the speed signal ■ detected by the speed detector 4 is input to the deceleration detector 9, and the deceleration detector 9 detects the actual deceleration timing based on this speed signal and decelerates. Output timing signal. The delay time calculator 10 receives the speed reference 2 of the speed reference generator 8 as one input, and the deceleration timing signal of the deceleration detector 9 as the other input, and calculates the speed reference V.
The difference between the deceleration timing of R and the actual deceleration timing, that is, the delay time Δt is calculated. A signal indicating this delay time Δt is taken into the delay distance calculator 11 via a switch that is closed during preliminary operation and opened during main operation. This delay distance calculator 11 calculates the set speed v8 and the delay time Δ.
Multiply by t and calculate the travel distance (rotation angle) of shear 1 Δ
S is calculated and the data is given to the deceleration point correction device 12.

The operation of this embodiment configured as described above will be explained below.

First, the deceleration target position is set by the deceleration target setting device 7,
The shear 1 is preliminarily operated for one cycle without actually feeding the material M. At this time, the speed reference generator 8 generates a speed reference VR proportional to the set speed V8 and provides it to the motor control device 3. The motor control device 3 controls the speed of the motor 2 according to this speed reference VR. At this time, the speed detector 4 gives a speed signal V of the shear to the deceleration detector 9, and the position detector 5 gives a position signal of the cutting blade to the deceleration point detector 6. Note that during preliminary operation, the deceleration point correction device 12 is reset, and the deceleration target position S set by the deceleration target setting device 7,
is the deceleration target position S after correction.

The signal is added to the deceleration point detector 6 as is. The deceleration point detector 6 gives a deceleration command to the speed reference generator 8 when the position of the cutting blade detected by the position detector 5 matches the deceleration target position S,'.

The speed reference generator 8 receives this deceleration command and inverts the polarity of the speed reference. In response to this polarity reversal, the motor control device 3 controls the motor 2 to decelerate. 2, deceleration detector 9
differentiates the detected speed V, detects the time when dV/dt<Q, and outputs a deceleration timing signal. Also,
The delay time calculator 10 calculates the generation delay time Δt of the deceleration timing signal of the deceleration detector 9 with respect to the timing at which the polarity of the speed reference VR changes from positive to negative. The delay distance calculator 11 inputs this delay time Δt, multiplies it by the set speed V8, calculates the travel distance ΔS that the shear 1 travels during that time, and stores this.

Next, during the actual operation of the shear 1, the deceleration point correction device 12
subtracts this travel distance ΔS from the deceleration target position SD set by the deceleration target setter 7, and obtains S.

-8, -ΔS is added to the deceleration point detector 6 as the corrected deceleration target position.

As a result, during the actual operation, the deceleration command is output earlier by a time corresponding to the travel distance ΔS. That is, the deceleration command is output when the cutting blade of the shear 1 reaches the initially set deceleration target position, so that the delay distance can be reduced to zero.

In this case, the reason why the delay distance calculator 11 calculates the traveling distance ΔS based on the delay time during preliminary operation is to prevent the speed drop (impact drop) during actual cutting from being regarded as deceleration. be.

In the above embodiment, the delay distance calculator 11 calculates the travel distance ΔS based on the delay time Δt calculated by the delay time calculator 10, and subtracts this travel distance ΔS from the deceleration target position S. Although the deceleration point detector 6 advances the deceleration command generation time based on the obtained deceleration target position S,',
Any other configuration may be used as long as it advances the timing of generation of the deceleration command by the shear delay time.

Furthermore, in the above embodiment, the deceleration detector 9 is dV/d
The deceleration timing signal was generated by detecting the time when t<Q, but instead, the deceleration timing signal was generated at the time when the speed va fell below the set speed VSET (-〇, 9 V8) corresponding to 90% of that value. Similar control can be achieved by allowing this to occur.

〔Effect of the invention〕

As is clear from the above explanation, according to this invention,
a speed detection means for detecting the actual speed of the shear; a deceleration detection means for detecting the timing of deceleration of the shear based on the output of the speed detection means; Since it is equipped with a delay time calculation means for detecting the delay time of the deceleration timing detected by the deceleration detection means, and a deceleration command correction means for advancing the generation timing of the deceleration command by the shear delay time, the capacity of the electric motor can be reduced. This has the effect that the influence of delay time can be reliably removed without increasing it.

Mouthparts, 7...Deceleration target setter, 8...Speed reference generator, 9...Deceleration detector, 1o...Delay time calculator,
11... Delay distance calculator.

Claims (1)

[Claims] A shear control device that generates a deceleration command when the cutting blade reaches a set deceleration target position and controls the speed of the shear according to a speed standard that switches from acceleration to deceleration when the deceleration command is generated. speed detection means for detecting the actual speed; deceleration detection means for detecting the timing of deceleration of the shear based on the output of the speed detection means; A shear characterized by comprising: delay time calculation means for detecting a delay time of the deceleration timing detected by the deceleration detection means; and deceleration command correction means for advancing the generation timing of the deceleration command by the delay time of the shear. control device.