JPH048124B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a tension control device, and particularly to a rolling stand (hereinafter referred to as a stand) of a continuous wire rolling mill.
The present invention relates to a tension control device suitable for maintaining constant tension between.

[Technical Background of the Invention] When rolling a rolled material using a continuous wire rolling mill, it is desirable to maintain the tension between the stands on the rolled material during rolling at a predetermined constant value. This is because tension fluctuations cause variations in product dimensions, making it difficult to eliminate variations in dimensions from a predetermined value.

A general method for controlling the tension between each stand in a continuous wire rolling mill will be described with reference to the schematic explanatory diagram of FIG. In addition, in FIG. 1, the rolled material 33, which is a wire rod, is
The manner in which the rolling material is rolled while passing through c is divided into state A, state B, and state C in order.

In state A, the rolled material 33 is rolled only by the stand 1a. Therefore, in this state, there is no tension. At this time, by measuring the rolling torque G ₀ and the rolling load P ₀ in the stand 1a under no tension, the lock-on value a ₀ of the torque arm of the stand rolling mill is calculated and stored using the following equation.

a ₀ = G ₀ /P ₀ ...(1) In this case, when measuring the rolling torque G, if the roll drive motor is a DC separately excited motor, its voltage V, current I, and rotation speed N are is measured, and the following calculation is performed: G=0.975V-IR _a /NI-k ₁ dN/dt-k ₂ (N+k ₃ )...(2). As a result, the rolling torque G can be determined indirectly. Here, R _a is armature resistance, k ₁ is a constant determined by the total inertia converted to the motor shaft, and k ₂ and k ₃ are constants. The first term on the right side of equation (2) represents motor output torque, the second term represents acceleration/deceleration torque, and the third term represents loss torque.

Next, in state B, the rolled material 33 is placed on the stand 1a.
Since it is rolled across both the stand 1b and the stand 1b, a tension or compression force is applied between the stands. In this case, the rolling torque G ₁ of stand 1a
By measuring the rolling load _P1 , the change in rolling torque due to tension △ _G1 can be found from △ _G1 = _a0・_P1 − _G1 ...(3). On the other hand, the tension between the stands, that is, the front tension T _f is calculated according to T _f =G−a ₀ ·P/K _f (4), and the tension between the stands is controlled. However, K _f is the forward tension coefficient. Also,
The rolling load and rolling torque are the rolling load P of the stand rolling mill, the rolling torque G, the front tension T _f ,
and rear tension T _b using the following formula.

= f (P, T _f , T _b ) = P ₀ −γ・T _f −δ・T _b ...(5) = f (G, T _f , T _b ) = G ₀ −α・T _f +β・T _b ) ...(6) where γ: Rolling load coefficient for front tension δ: Rolling load coefficient for rear tension α: Rolling torque coefficient for front tension β: Rolling torque coefficient for rear tension. In this case, the following equation is obtained by transforming equation (4).

a ₀ = G−K _f・T _f /P ...(7) As is clear from the above equation (7), in order to obtain the torque arm lock-on value a ₀ of the stand rolling mill, the Forward tension T _f , backward tension
T _b , rolling load P and rolling torque G must each be known. Here, the forward tension T _f
If is positive, it means that tension is working between the stands, and if it is negative, it means that compressive force is working.

Now, if the target tension between the stands 1a and 1b is T _R1 , the tension between the stands 1a and 1b is controlled by modifying the drive motor speed of the stands 1a by _ΔN1 . The correction value △N ₁ in this case is △N1 (S) = T ₁₁ + T ₁₂ S/S × (a ₁₀・P ₁ (S) − G ₁ (S) − KR ₁・TR ₁ ) ……(8) becomes. However, S is the Laplace operator, T ₁₁ , T ₁₂
is the control constant and K _R1 is the target tension coefficient.

Note that a ₁₀ · P ₁ (S) - G ₁ (S) in the above formula (8) corresponds to the rolling torque change ΔG ₁ , and (a ₁₀ · P ₁
(S)-G ₁ (S)-K _R1 ·T _R1 ) is called the tension torque deviation value.

Next, in the same state B, the rolling torque G ₂₀ and the rolling load P ₂₀ in the stand 1b under no tension are estimated and stored. Stand 1a and stand 1 in state B
Although there are cases where the tension between b is controlled to reach the target tension value, it is generally considered that some kind of tension or compression force is acting. Rolling torque change according to tension between stand 1a and stand 1b△
If G ₂ is detected by stand 1a, it is expressed by equation (3), but from the relationship that the electric power due to tension is equal when viewed from stand 1b, △G ₂ = (ω ₁ /ω ₂ ) △G ₁ ... (9) becomes. However, ω ₁ and ω ₂ are each stand 1a.
and the angular velocity of the drive motor 1b. Therefore, the actual measurement value of the rolling torque of stand 1b in state B is G ₂
Then, the rolling torque of stand 1b when there is no tension is
G ₂₀ becomes G ₂₀ =G ₂ −(ω ₁ /ω ₂ )·△G ₁ ……(10).

On the other hand, the rolling load decreases when front tension and rear tension are applied, but in a continuous wire rolling mill, the tension stress between stands is reduced to a minute value, for example, 0.0 to 1.0 Kg/mm ²
Rolling is done at In this case, the influence of tension on rolling load can be approximately ignored. Therefore, if the actual measurement value of rolling load at stand 1b is P ₂ ,
The rolling load P ₂₀ when there is no tension is P ₂₀ = P ₂ ... (11).

Stand 1 calculated by the above calculation
The rolling torque G ₂₀ and rolling load P ₂₀ at the time of no tension at b are memorized.

Next, in state C, stand 1a and stand 1b
A tension or compression force is exerted between the stand 1b and the stand 1c. In this case, the tension between the stands 1a and 1b is controlled based on equation (2). Considering the rear tension of stand 1b, the tension between stand 1b and stand 1c is calculated as follows: △N ₂ (S) = T ₂₁ + T ₂₂ S/S [a ₂₀・P ₂ (S) − (G ₂ (S)
) −ω ₁ (S)/ω ₂ (S)△G ₁ (S)) −K _R2・T _R2 ]…
...(12) It is controlled based on the following formula. Here, ΔN ₂ is the drive motor speed control amount of the stand 1b, T ₂₁ and T ₂₂ are control constants, T _R2 is the target tension between the stands 1b and 1c, and K _R2 is the target tension coefficient.

Further, by controlling the drive motor speed of the stand 1b, the volume velocity is kept constant so that the tension between the stands 1a and 1b does not change. For this purpose, the speed correction expressed as △N ₁ ′=(N ₁ /N ₂ )△N ₂ (13) is performed at the stand 1a.

By sequentially performing the above calculations, tension control between each stand can be realized.

[Problems with background technology]

However, when attempting to apply such a system to a tension control device for an actual continuous wire rolling mill, the following problems arise.

That is, the rolled material 33 is placed on each rolling stand 1a,
By passing through 1b and 1c, the tension between the stands changes rapidly. In addition, the lock-on value of each stand that is locked on when the rolled material is biting changes, and the tension control system detects a very large tension fluctuation. If the control system operates in an attempt to eliminate this large fluctuation, a problem arises in that a hunting phenomenon occurs and stable control cannot be achieved.

[Purpose of the invention]

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and to perform high-precision constant tension control without being affected by changes in the lock-on value of the torque arm when the tail end of the rolled material passes through each stand. Do it with
An object of the present invention is to provide a tension control device that enables stable rolling mill control.

[Summary of the invention]

a detection means for detecting the rolling load of a rolling stand of a continuous wire rolling mill, the voltage, current, and rotation speed of a drive motor; a first calculating means for calculating a change in rolling torque of the rolling stand when rolling is started on the rolling stand; and a first calculating means for calculating a change in rolling torque of the rolling stand when rolling is started on the rolling stand; In addition to calculating the rolling torque change,
a second calculation means for calculating a tension component torque deviation value which is a deviation from the rolling torque change amount of the first calculation means; inputting the tension component torque deviation value and causing the rolled material to pass through the rolling stand; A signal holding means that holds and outputs a signal from the previous time until a certain time after passing, and a third calculation that calculates a speed command change amount to zero the tension torque deviation value output from this signal holding means. and means for correcting the speed command of the drive motor of the stand in accordance with the speed change command.

[Embodiments of the invention]

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

FIG. 2 is a schematic configuration diagram of a tension control device according to an embodiment of the present invention. As shown in the figure, the continuous rolling mill has stands 1a to 1n each having rolling load cells 2a to 2n and roll drive motors M ₁ to M _o.
It consists of Load detection signals P ₁ to _{P o} of the rolling load cells 2a to 2n are sent to the calculation device 100.
Terminal voltage detectors 3a to 3n, main circuit current detectors 4a to 4n, and speed detection pulse oscillators 5a to 5n are provided for the electric motors M ₁ to _{M o} , respectively, and voltage detection signals V ₁ to V _o , Current detection signals I ₁ to I _o and speed detection signals N ₁ to _{N o} are provided to arithmetic device 100 . Tension reference values T _R1 from tension setting devices 6a to 6n that set the tension between each stand 1a to 1n
T _Ro is given to the arithmetic device 100. Arithmetic device 1
At 00, a signal corresponding to the tension deviation signal between each stand 1a to 1n is calculated, and a speed correction signal ΔN of the motor M ₁ to M ( _{o-1) is} sent to the motor speed control device 7a to 7 _(o-1). It is given as ₁ ~△N _(o-1) . Motor speed control devices 7a to 7 _(o-1) include speed reference signals from speed setters 8a to 8n, and speed detection pulse oscillators 5a to 7 (o-1).
Speed detection signals N ₁ to _No from 5n and arithmetic unit 1
Based on the speed correction signals ΔN ₁ to ΔN _(o-1) from 00, the speeds of the electric motors M ₁ to M _o are controlled via the drive units 9a to 9n.

FIG. 3 is a block diagram for explaining the functions of the arithmetic device 100. In the figure, the rolling torque calculation unit 21 outputs a voltage detection signal V ₁ of the stand drive motor, a current detection signal I ₁ , a speed detection signal N ₁ , a load detection signal P ₁ of the rolling load meter, and various other signals necessary for tension control. constant
k ₁₁ , k ₁₂ , k _{13 ,} etc. are input, and the rolling torque G ₁ is calculated using the input data according to the equation (2) described above. The torque arm value calculation unit 22 calculates a torque arm lock-on value a 10 from the rolling torque G ₁₀ at the time of no tension and the rolling load P ₁₀ at that time based on the output signal from the lock-on timing detection unit 30, and locks on the torque arm value a ₁₀ . Remember. The rolling torque change calculation unit 23 based on the inter-stand tension calculates the rolling torque change value ΔG ₁ using equation (3). The tension component torque deviation calculation unit 24 calculates the tension setting value T _R1 from the tension setting device 6a.
is multiplied by the target tension coefficient K _R1 , and the rolling torque change value ΔG ₁ is set as a ₁₀・P ₁ (S) − G ₁ (S).
The tension torque deviation value expressed as (a ₁₀ · P ₁ (S) - G ₁ (S) - K _R1 · T _R1 ) in equation (8) is calculated. The tension component rolling torque deviation signal holding section 25 stores a certain period calculated by the hold timing circuit section 27.
The tension torque deviation value from the tension torque deviation calculating section 24 is held and output. Speed change amount calculation unit 26
inputs the tension component torque deviation value signal from the tension component torque deviation calculation section 24, and calculates and outputs the speed command change amount ΔN ₁ to make this signal zero.
In this case, the speed command change amount ΔN ₁ based on equation (8) is obtained as an output by multiplying by the gains T ₁₁ and T ₁₂ necessary to stabilize the control characteristics. Then, as mentioned earlier, the speed of the stand 1a is corrected based on this speed command change amount ΔN ₁ . Note that the speeds of the other stands 1b to 1n are also corrected through the same configuration.

FIG. 4 is a schematic diagram of the hold timing circuit section 27 shown in FIG. 3. In the figure, a detector 31 detects the passage of a rolled material 33. The hold timing circuit section 27 determines the holding timing based on the output signal of the detector 31 and the output signal of the pulse generator 32 that generates a pulse signal as the table roller 34 rotates to detect the transfer speed of the rolled material 33. do. The rolled material passage detection calculation unit 27a determines whether the tail end of the rolled material 33 is on the stand 1 based on the detection signal from the detector 31 of the rolled material 33 and the pulse signal from the pulse transmitter 32 for detecting the speed of the rolled material 33.
It detects that the material has arrived just before point a and outputs a holding signal, and resets this holding signal at a certain time after passing through stand 1a, that is, at the time when the time required for the material to reliably pass through stand 1a has elapsed. Has a function. The holding signal generated through this configuration is given to the tension component rolling torque deviation signal holding section 25 as described above.

By the way, when the rolled material 33 passes through the stand 1a, the tension between the stands 1a and 1b disappears, and the rear tension of the stand 1b disappears. Now, suppose stand 1a and stand 1b
If the tension between stands 1 and 1 is positive, then stand 1
The rolling load b increases, and the rolling torque also changes accordingly. Therefore, the torque arm value _a2 changes and the torque arm lock-on value ₂₀ also becomes unknown.
Here, if the tension between stands 1b and 1c changes due to a change in the torque arm value _a20 of stand 1b, then the tension between stands 1c and 1d will also change (4), (5), (6). ) changes from the expression.

For example, the rolling load and rolling torque of each stand 1b to 1n at the time when the tail end of the rolled material 33 passes through the stand 1a are P _n and G _n , and the torque arm value is a _n (however, m = b to n ), then
The torque arm value of each of the stands 1b to 1n can be determined by equation (7) as described above. The forward tension T _fo of stand 1n is the same as when the rolled material is on stand 1a.
It is zero because it is not affected by passing through. Therefore, the rear tension T _bo of the stand 1n can be determined from equation (4) as follows.

T _bo = G _o −a _o・P _o /K _fo ...(14) Here, the rear tension T _bo of this stand 1n is the tension between stand 1 _(o-1) and stand 1n, and stand 1 _{( o-1)} is equivalent to the forward tension T _f(o-1) , so
The rolling load _{(o-1 ) and rolling torque (o-1} ) of stand 1 ( _o-1) are expressed as follows.

_(o-1) = f(P _(o-1) , T _b(o-1) )...(15) _(o-1) = f(G _(o-1) , T _b(o-1) )...(16) And the rolling load ( _{o-1) of this stand 1 ( o-1)}
From the rolling torque _(o-1), the rear tension T _{b (o-1) of stand 1 (o} -1), that is, the front tension T f _{(o-2) of stand 1 (o -2)} is calculated as T _{f (o -2)} =T _b(o-1) =G _(o-1) −a _(o-1)・P _(o-1) /K _f(o-1) ……(17) Based on the formula calculate.

Similarly, the front and rear tensions of each stand can be calculated using the relational expressions (15), (16), and (17). Therefore, the torque arm lock-on value a _n when the rolled material 33 passes the tail end of the stand 1a is the forward tension T _{f (n-1)} obtained by the above method,
Back tension T _bn , rolling load P _n and rolling torque G _n
It is calculated by the formula a _0(n-1) = G _0(n-1) /P _0(n-1) (18). However, in equation (18), _0(n-1) and _0(n-1) take into consideration the influence when the rear tension T _b(n-1) is not zero, and is expressed as follows.

P _0(n-1) = f(P _(n-1) , T _b(n-1) , T _f(n-1) )
...(19) G _0(n-1) = f(G _(n-1) , T _b(n-1) , T _f(n-1) )
...(20) From this, the forward tension T _{f (o-1) of stand 1 (} o- ₁ ) determined by equation (14) is
₎ is the value _assuming that the rear tension T b ( _{o -1) of} have to ask. Therefore, the torque arm lock-on value of stand 1 _c calculated by equation (18) is
Based on a〓 ₀₃ , calculate and detect the forward tension T〓 _f3 of stand 1 _c using the following formula.

T〓 _f3 = G ₃ −a〓 ₀₃ P ₀₃ /K _f3 ...(21) Hereinafter, calculate the torque arm lock-on value for each stand in the same way, and use the relational expression (21) to calculate the torque arm lock-on value for each stand. It is possible to control the tension between each stand by determining the front tension between _b and _1o .

In the above embodiment, the tension between each stand is controlled by updating the torque arm lock-on value, but even if the tail end of the rolled material 33 passes through the rolling stand, the torque arm The same effect can be obtained by simply holding the process data or the control output value without updating the lock-on value.

Further, in the above embodiment, the arithmetic unit is configured with a discrete circuit, but the implementation of the present invention is not limited to this, and it goes without saying that it may be configured with a programmable controller using a computer. It is.

〔Effect of the invention〕

As described above, according to the present invention, there are significant fluctuations in rolling load and rolling torque when the tail end of a rolled material passes through each stand in a continuous rolling mill, and fluctuations in inter-stand tension after the rolled material passes through each stand. without being affected by changes in torque arm lock-on value due to
It is possible to obtain a tension control device that can stably control the tension between the stands to a required value.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram for explaining a general method for performing tension control, FIG. 2 is a schematic configuration diagram of a tension control device according to an embodiment of the present invention, and FIG. 3 is a diagram of a calculation device. FIG. 4, a block diagram for explaining the functions, is a schematic diagram of the hold timing circuit section shown in FIG. 3. 1a, 1b to 1n...Stand, 33...Rolled material, 2a...Rolling load cell, 3a...Terminal voltage detector, 4a...Main circuit current detector, 5a...Pulse oscillator for speed detection, 6a... ...Tension setting device, 7a...
...Electric motor speed control device, 8a...Speed setter, 9
a...Drive unit, 100...Arithmetic unit.

Claims (1)

[Claims] 1. Rolling load of rolling stand of continuous wire rod rolling mill,
a detection means for detecting the voltage, current, and rotation speed of the drive motor; and rolling when the rolled material starts rolling in the forward rolling stand based on the detected rolling load, voltage, current, and rotation speed of the drive motor; a first calculating means for calculating a change in the rolling torque of the stand; a second calculation means for calculating a tension torque deviation value which is a deviation from the rolling torque change of the first calculation means; and a time immediately before the tension torque deviation value is input and the rolled material passes through the rolling stand. A signal holding means for holding and outputting a signal from the time to a certain time after passing, and a third calculation means for calculating a speed command change amount to zero the tension torque deviation value output from the signal holding means. A tension control device comprising: correcting a speed command of the drive motor of the stand based on the speed change command.