SU1712080A1 - Arrangement to control flying shears - Google Patents

Abstract

The invention relates to mechanical engineering, in particular to equipment systems for controlling flying scissors operating in a continuous rotation mode and equipped with a speed equalization mechanism. The aim of the invention is to improve the cutting accuracy and improve the ja4ecTBa of the cut, which is achieved: by increasing the speed of the analog and digital speed control throughout the entire cut cycle by changing the gain! in the speed control loop, it is proportional to the actual current, the value of the total moment of inertia of the drive, calculated by the inertia moment calculator. 2 Il. The invention relates to mechanical engineering, in particular, to the design of control systems for flying scissors equipment operating in continuous rotation mode and equipped with a leveling-speed mechanism (MIF) system used in high-speed cross-cutting units for rolled steel and installed between a drive motor and drums flying shears (LF) for leveling the linear speed of the blades with the rolling speed at the time of cutting. At the same time, the magnitude of the eccentricity installed in the MIF is uniquely determined by the specified rolled cutting length and the reel diameter L N. The specified cutting length is provided by controlling the LF drive speed and rolling speed, which is average for one revolution, and has a known baking elements, one of which is connected to the correct machine, and the other to the shaft of the scissors leading drum. The disadvantage of this system is the presence of a special brake motor and system pack ION thereto, which significantly complicates it, and also a very small dia 00O N O

Description

the range of variation of precisely cut lengths due to the very limited deformation zone of the elastic-damping elements (on the order of 5 °). In addition, during transitions to other cutting lengths, as well as technological changes in the speed of the rolled steel in this system, it is necessary to additionally rotate the cut sensor to eliminate jerking during cutting.

A device for controlling flying scissors operating in a continuous rotation mode is known, in which a digital-analogue tracking system for a shear engine in accordance with a predetermined length is actually implemented by means of sensors for rolling and scissors, a code-frequency converter, a reversible counter, and some other elements. cutting.

The disadvantages of this device are the lack of precision in cutting lengths and the deterioration of the cut quality, due to the discrepancy between the linear speed of the shears and the rolling speed at the time of the cut, as well as the cyclic loss when the reversing counter of the digital regulator is zeroed, which compensates for the error in the analog speed control.

It is also known to control a flying scissors device containing matching units for position and speed, as well as first, second and third correction units. The device detects an error in the length of the cut, compares it with the tolerance and, if necessary, proceeds to eliminate it.

The disadvantages of this device are the increased complexity as well as the lack of accuracy of cutting, caused by the slow elimination of errors in the length of cutting, which is especially unacceptable for high-dynamic cross-cutting units for rolled steel.

Closest to the present invention, there is a flying shear control device operating in continuous rotation mode, comprising a drive, a tachogenerator, a shear motion sensor and a shear sensor, a rolling car motion sensor associated with rolling by means of measuring shears, connected to the shear shaft. rollers, serially connected code frequency converter, reversible counter, first code-voltage converter and speed controller, in series An irreversible counter, a dynamic torque compensation unit, a second code-voltage converter and a multiplication unit, as well as a quadrant, a frequency-voltage converter, and a setpoint generator. This device works as a digital analogue.

A tracking system for adjusting the shear motor speed level in accordance with a predetermined cutting length, and to eliminate the effect on the drive motor shaft variable in the cutting cycle of the dynamic moment caused by the uneven rotation of the shaft of the reel LI, it is compensated by forming a dynamic setting signal in each cycle of cutting. current and feed it to

5 second input of the current LI drive regulator.

However, such a device is characterized by an insufficient accuracy of cutting the measured lengths and deterioration of the cut quality caused by fluctuations in the speed

0 engine from the action of not fully compensated dynamic torque. The effect of inaccurate compensation arises due to the time mismatch of the dynamic current setting signal to the actual

5 dynamic moment taking into account the inertia of the current control loop. Moreover, the marked fluctuations in engine speed cannot be eliminated by analogue 1L digital speed controllers due to their reduced speed. In turn, the gain factors of the analog and digital speed controllers, which determine their speed, are selected from the conditions of stability and a given quality of process control depending on the parameters of the power part of the system, in particular, on the moment of inertia of the moving masses. With MBC, the total moment of inertia, reduced to the motor shaft, due to the variable in the cutting cycle, the MBC ratio is a variable value, and under the conditions of stability, the speed controllers are calculated taking into account the smallest value of the total ijertion moment, which means that for a significant parts of the turn LI, when; and the total moment of inertia of the drive is significantly greater than the minimum, the speed regulators have

0 reduced speed and can not eliminate fluctuations in the speed of the drive motor shaft from the action of a not fully compensated dynamic torque.

5 The purpose of the invention is to improve the cutting accuracy and improve the quality of the cut.

The goal is achieved by inserting inertia computing unit in series, a third code-voltage converter and a second multiplication unit, the second input of which is connected to the output of the speed controller, and the output connected to the first input of the scissor drive, and the output of a non-reversible counter connected to the first input of the inertia calculation unit, the second input of which is connected to the output of the length adjuster.

Figure 1 shows the functional diagram of the device; figure 2 is a functional diagram of the drive of volatile scissors.

The device contains a drive 1 of flying scissors (LN) 2, articulated with a drive through a speed equalization mechanism 3 (MVC). A tachogenerator4 is connected to the shear drive shaft, the pulse sensor 5 is moved1; 1 shears and the cut sensor 6. With rental 7, by means of measuring rollers 8, a pulsed 9 displacement sensor for rolling is connected.

The digital LI drive speed control loop includes a code-frequency converter 10 as a frequency driver associated with a length setting device 11, a reversible counter 12, a first code-voltage converter 13, an analog speed control loop, and a sensor 5.

The analog speed control loop includes a speed controller 14, a flying scissors drive 1 and a tachogenerator 4, and a frequency-voltage converter 15 as an analog speed reference. ,,

The dynamic moment compensation channel is constituted by a non-reversible counter 16, a dynamic torque compensation unit 17, a quad 19, a second code-voltage converter 18 and a first multiplication unit 20.

The compensation channel of the variable inertia moment comprises the inertia calculation unit 21, the third code-voltage converter 22, and the second multiplication unit 23.

The flying scissors drive 1 comprises a drive motor 24 fed from a power amplifier 25 (such as a thyristor converter, for example, and a drive motor current regulator / including a current regulator on the amplifier 26 and a current sensor 27.

The device works as follows.

Mere cutting of rolled products to specified lengths is carried out by continuous digital adjustment of the angular velocity.

motor scissors according to the expression

UE RH

2

(1) U 1h

where Vn is the rolling speed;

RH, LO — radius and perimeter of LN samples, respectively;

U is the specified length of the cut sheets. The regulation of the angular velocity of the scissor motor in accordance with the relation (1) is realized by forming the frequency signal of the task in accordance with the expression

LO

(2)

fa fn

U

where fn- frequency signal from sensor 9, proportional to the speed of hire.

Frequency converter 15 converts the signal fa into an analog signal proportional signal Un

drive speed. The exact maintenance of the speed of the LF drive at a level corresponding to the frequency fa is carried out by means of static digital regulation using a reversing counter 12,

which compares the frequency of setting fa and feedback in from sensor 5. The first code-voltage converter 13 converts the output signal of the reversible counter 12 into the analog signal AU, continuously:

jerky compensating error of the analog loop for adjusting the shear drive speed. MVSZ converts the uniform rotation of the shear drive into an uneven rotation within one turn

drums LN so that, retaining the average speed per revolution, ensure at the time of the cut the equality of the linear speeds of the shears and rolled knives. The magnitude of the eccentricity of the MBC 3 is set

depending on the cut length in accordance with the ratio

.

(3)

  Mr. La N- LO

where kr is the relative and absolute eccentricity of the AIM;

r is the radius of the MFV cranks

The uneven rotation of the shaft of the LN drums inside each revolution causes the appearance of dynamic moments on the shaft of the drive motor, as a result of which the speed of the shaft of the drive motor oscillates, negatively affecting

on accuracy of cutting of the cut-off lengths and quality of a cut. Since the noted dynamic moment depends on the established eccentricity, i.e. from a given length of the cut sheet, and is a function of the angle of rotation of the drive shaft

1b ftj | F (L3, a),

M

din

where 1b is the moment of inertia of the drums LN;

F (1-h. O;) is the relative dynamic moment, i.e. at a single angular velocity of the drive shaft and at a single moment of inertia of the LF drums, in order to partially eliminate its effect on the drive motor shaft, it is compensated by generating in each cutting cycle a signal for setting the dynamic current Uu and feeding it to the second regulator input 26 drive current 1 LN. For this purpose, in the non-reversible counter 16, from the time determined by the cut sensor signal, an angle code A of the rotation of the drive motor shaft is generated by counting the frequency pulses TH. In block 17, the compensation of the dynamic moment by the value of the codes a and U forms the code Md of the relative dynamic moment F (L3, a) corresponding to the current value of the rotation angle of the drive shaft for a given cutting length. Block 17 is made on the basis of a programmable memory element, each memory page of which is defined by a code La, the address of a cell in each page is code a, and the contents of each memory cell is a code Id which is converted by the converter 18 into proportional voltage Oud, the last in block BU-1 20 multiplied by

about

signal KSD, coming from the output of the quadrant 19. Thus, at the output of the first multiplication unit 20, a signal is formed and | d setting the dynamic current in full accordance with expression (4). At the time of the arrival of the next signal from the cut sensor, the non-reversible counter 16 is reset, and the operation cycle of block 17 is repeated.

Due to the time mismatch, taking into account the inertia of the current control loop of setting the dynamic current to the actual dynamic moment with changes over a wide range of engine operating speed, the specified dynamic moment is incompletely compensated for, resulting in engine speed fluctuations. Therefore, to effectively eliminate these oscillations, a channel of compensation for a variable moment of inertia is implemented, which allows one to achieve

maximum speed of analog and digital speed controllers throughout the entire cutting cycle. It is known that in subordinate control systems

parameters to achieve maximum speed in the speed control loop when the specified stability requirements are met, the speed regulator coefficient should be proportional to the inertia moment of the electric drive. Therefore, the output of the speed controller 14 is multiplied in the second block 23 multiplying by a signal Ui proportional to the NI code of the total moment of inertia U

motor with MVS, which is determined by the ratio

1 1d + 1b 2 (1з, ")

(five)

where 1D - the moment of inertia of the engine;

i (L3, Q;) instantaneously, the value of the gear ratio MBC.

An NI code is generated in block 21 of calculating the moment of inertia from the magnitude of the codes.

About: and La.

The inertia moment calculation unit 21, like block 17, is made on the basis of a programmable memory cell, each page of which is defined by code-1h, address

The cells in each page are identified by a code, and the contents of each cell are an NI code. Block 21 operates cyclically, synchronously with block 17, and the cycle is determined by the growth of the content of the non-reversible counter 16 and its zeroing at the time of the cut.

Thus, the application of the invention improves the quality and accuracy of the cut by increasing the speed

analog and digital speed controllers throughout the entire sheet cutting cycle by changing the gain in the speed control loop is proportional to the actual current

the value of the total moment of inertia of the electric drive, which is determined in the block of calculation of the moment of inertia.

Claims (1)

Claim control device with a flying shear equipped with a speed equalization mechanism, comprising a flying shear drive, a tachogenerator, a shear displacement sensor and a cutting sensor, a rolling motion pulse sensor connected in series code-frequency, reversible counter, first code-voltage converter and speed controller, serially connected non-reversible counter, dynamic torque compensation block, second code-voltage converter and multiplication unit, as well as a quad, frequency-voltage converter and output roll cut-off meter whose output is connected to the code input of the converter, the code is the frequency, the pulse input of which is connected to the output of the pulse, the movement sensor of the rolled product, and the output through the frequency-voltage converter to the second input of the controller with speed, output pulse displacement sensor; the scissors is connected to the second input of the reversible counter and the counting input of the non-reversible counter, the reset input of which is connected to the output of the cut sensor, the output of the setting device for the length of the rolled roll is connected to the second input of the dynamic torque compensation unit, and the output of the tachogenerator is connected to the third input of the speed regulator and the square input, output which is connected to the second input of the multiplication unit, the output of the multiplication unit is connected to the second input of the flying scissors drive, characterized in that, in order to increase the cuts1: and and improving the quality of the cut, it is equipped with a series of inertia calculation units, a third code-voltage converter and a second multiplication unit, the second input of the second multiplication unit connected to the output of the skrrosity controller, and the output to the first input of the volatile drive scissors, the output of the non-reversible counter is connected to the first input of the inertia time calculator, to the second input of which the output of the unit for the length of the cut sheet is connected. FIG. i Fav.