JPH0462807B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a control method for controlling the drooping amount of a free loop formed in the middle of a running line of a strip material to be substantially constant. [Prior Art and its Problems] Conventionally, as a method for controlling the position of a free loop of a strip material, there are a method using a photorelay as shown in FIG. 1, and a method not using a photorelay as shown in FIG. The method using a photorelay shown in Fig. 1 places optical detectors 1 and 2 above and below, and when detector 1 detects free loop l (when the speed on the control side is set higher than the speed on the reference side) ), the variable resistor is set for a certain appropriate time from the speed command value of the drive motor _M2 on the control side to the timer switch _T1 .
Free loop l by subtracting the corrected command value by R ₁ and making the traveling speed υ ₂ on the control side slower than the speed υ ₁ on the reference side.
Let the lower end of the hang down to the middle position between detectors 1 and 2,
On the other hand, if the speed on the control side is set smaller, the free loop L is hung to block the light entering the detector 2, and the speed command value on the control side is set to the timer switch _T2 . By adding a corrected command value using variable resistor R ₂ for a certain appropriate time, the traveling speed υ ₂ on the control side is made faster than the speed υ ₁ on the reference side, and the lower end of the free loop l rises to the intermediate position between detectors 1 and 2. This is a method of controlling the sensor so that it does not deviate from the range where detectors 1 and 2 are installed. This free loop control method is called on-off control, and if the speed command value is inappropriate and there is a speed difference between the reference side and the control side, the lower end of the free loop l will be at the intermediate position between detectors 1 and 2. Even after returning, the amount of drooping of the free loop changes again, so vertical movement of the lower end of the free loop will always occur unless the speed command value is manually adjusted. Therefore, in the case where, for example, a vertical annealing furnace 3 is provided in this free loop forming part to anneal the strip material, there is a problem in terms of annealing performance because the residence time cannot be maintained substantially constant. Furthermore, the control method shown in FIG. 2 is a method in which the free loop drooping amount is electrically controlled using the digital arithmetic and control device 4 without using the optical detector as described above. There is a problem with the settings of speed detection coefficients K ₁ and K ₂ on the reference side and control side for speed control. In other words, since the adjustment and setting of K ₁ and K ₂ is generally done by the digital control device 4 installed in the electrical room, the operator can adjust and set K 1 and K 2 while observing the movement of the lower end of the free loop l on site. Since it is impossible to set the speed detection coefficient, it is actually troublesome that a plurality of workers have to communicate with each other. Furthermore, even after the adjustment and settings are completed, the speed detection coefficient value changes due to fluctuations in various factors, so if the deviation becomes large enough to be ignored, readjustment is required, which solves the problem of difficulty in setting as described above. Recurrence. [Means for solving the problem] The present invention has been made to solve _this problem _. Each speed υ ₁ = K ₁・
Find V ₁ , υ ₂ = K ₂ · V ₂ (K ₁ , K ₂ are speed detection coefficients), integrate the difference between them to find the fluctuation at the lower end of the free loop, and calculate the speed correction signal according to that fluctuation. In a strip material free loop control device, the speed of the control side is corrected using the speed correction signal, and in the event of a control abnormality, the free loop is returned to its normal position by on-off control. Before starting automatic operation of position control, that is, before starting speed control on the control side, a certain bias value is added to the control side to increase the speed on the control side, and the lower end of the free loop is adjusted to a certain appropriate value. The reference side speed detection coefficient _K1 or the control side speed detection coefficient _K2 is determined by passing between two optical detectors installed at a certain position and measuring the required time _T0 , and the determined speed This is a free-loop control method for strip material, which is characterized by controlling the speed on the control side using a detection coefficient. In addition, the second invention calculates each speed υ ₁ = K ₁ · from the detected speed values V ₁ and V ₂ of the strip material on the reference side and the control side.
Find V ₁ , υ ₂ = K ₂ · V ₂ (K ₁ , K ₂ are speed detection coefficients), integrate the difference between them to find the fluctuation at the lower end of the free loop, and calculate the speed correction signal according to that fluctuation. The free-loop control device for strip material is capable of automatically operating the free-loop control device, which is capable of correcting the speed on the control side using the speed correction signal, and returning the free-loop to its normal position using on-off control in the event of a control abnormality. Two optical detectors are installed above and below to sandwich the bottom end of the free loop when the free loop is running.When the bottom end of the free loop shifts and one detector operates twice in a row, the time since the previous operation The interval T _s is measured, the reference side speed detection coefficient K 1 or the control side speed detection coefficient K 2 is corrected according to the measured time interval T _s , and the corrected speed detection coefficient is used to detect the control side speed detection coefficient K ₁ or the control side speed detection coefficient K ₂ . This is a free-loop control method for strip material characterized by automatic speed control. [Operation] The first invention forcibly changes the lower end of the free loop before starting operation to obtain an appropriate speed detection coefficient.
This is a method in which K ₁ or K ₂ is determined by a digital arithmetic controller and the speed detection coefficient is used to control the speed on the control side. It becomes possible to control the drooping amount of the free loop with high precision. Further, in the second invention, when the speed detection coefficient set before the start of operation becomes inappropriate for controlling the amount of free loop droop during operation, the digital arithmetic and control device determines the appropriate speed detection coefficient. The position of the lower end of the free loop is controlled using the newly determined speed detection coefficient, so the first
It is no longer necessary to manually change the speed command value or the degree detection coefficient each time there is a fluctuation during driving as in the conventional method shown in FIGS. [Example] An example of the present invention will be described below based on the drawings. FIG. 3 shows a block diagram of the embodiment.
_M1 is a reference side drive motor driven by the thyristor control device 5; _M2 is a control side drive motor driven by the thyristor control device 5';
ASR is a speed control device, and 6 is a digital arithmetic control device. In this embodiment, the outlet speed is controlled using the inlet side of the free loop l as the speed reference side, and speed generators PG ₁ and PG are connected to drive motors M ₁ and M ₂ on the inlet and outlet sides, respectively. ₂ of said strip material
Detecting V ₁ and V ₂ , the digital arithmetic and control device 6
A-to-D conversion circuits 611 and 612 perform A→D conversion, and multiplication circuits 614 and 615 multiply by speed detection coefficients K ₁ and K ₂ to perform weighting, and an addition circuit 616 calculates the difference and performs integration. circuit 6
After integrating in step 17 to find the amount of variation (distance), D-A
The conversion circuit 613 is configured to perform D-A conversion to obtain a speed correction output. That is, the speed control system on the control side is operated using the speed signal of the speed control system on the reference side as a speed command, and the control is performed in which the integral control output of the digital arithmetic and control device 6 is used as the speed correction signal for the speed control system on the control side. It has become a system. In the figure, 618, 620, and 621 are switches operated by a control device (not shown), 618 is an automatic operation switch that is turned on when the initial operation is completed, which will be described later, and 620 is an automatic operation switch that is turned on when the initial operation is completed, which will be described later. , 2 are both shielded from light; 621 is a deceleration switch that is turned on when free loop l does not shield detectors 1 and 2 during initial operation, which will be described later; and 619 is an adder circuit. 622 is a speed bias command circuit with linear acceleration,
When the acceleration switch 620 is turned on, the positive speed bias υ ₃ is added to the addition circuit 619 and the D-A conversion circuit 61.
3 to the adder circuit 8 to add the speed on the control side, and when the deceleration switch 621 is turned on, the negative speed bias υ ₃ is sent to the adder circuit 8 via the adder circuit 619 and the D-A converter circuit 613. It is designed to reduce the speed of the control side. Further, 623 is a clock pulse generator, 62
4 is the time required for the lower end of the free loop to pass the distance L ₀ between detectors 1 and 2 by adding the speed bias υ ₃
Counters 625 and 626 measure T ₀ and a time interval T _s to be described later, and 625 and 626 are arithmetic circuits that apply K ₁ and K ₂ to multiplier circuits 614 and 615, respectively, and the arithmetic circuit 626 is a preset input side. A calculation is performed to determine the exit speed detection coefficient K ₂ corresponding to the speed detection coefficient K ₁ according to the value of T ₀ detected by the counter 624, and the calculation circuit 625 determines the entrance speed detection coefficient K by the method described later. ₁ from a preset value to a value corresponding to the value of T _s detected by the counter 624, and K ₁ and K ₂ respectively updated or determined by these operations are added to the multiplier circuit 614, 615. Note that a sequence is set up so that the following steps are taken after the line operation is started to measure the time T ₀ .

[Table] Detector 1 light passing 〓

↓
↓
Add an appropriate amount of reverse bias
Expressing the speed detection coefficient _K2
to slow down the control side.
calculate
Free loop lower end

Almost between detectors 1 and 2

It also comes

↓

Start loop position control

Claims (1)

[Claims] 1. Speed detection values of the strip material on the reference side and the control side
Find each speed _{υ 1 =} K ₁・V ₁ , υ ₂ = K ₂・V _{2 from V 1 and V 2 (} however, K ₁ and K ₂ are speed detection coefficients), integrate the difference between them, and perform a free loop. Find the fluctuation of the lower end, create a speed correction signal according to the fluctuation, correct the speed on the control side using the speed correction signal, and in the case of a control abnormality, use on-off control to return the free loop to its normal position. In a strip material free-loop control device that uses a digital arithmetic and control device, the bias value on the control side is The speed on the reference side is detected by _increasing the speed on the control side by adding It is characterized by determining the coefficient K ₁ or the control side speed detection coefficient K ₂ and performing automatic operation of the position control of the lower end of the loop by performing speed control on the control side using the determined speed detection coefficient. Free loop control method for strip material. 2 Speed detection values of the strip material on the reference side and control side
Find each speed _{υ 1 =} K ₁・V ₁ , υ ₂ = K ₂・V _{2 from V 1 and V 2 (} however, K ₁ and K ₂ are speed detection coefficients), integrate the difference between them, and perform a free loop. Find the fluctuation of the lower end, create a speed correction signal according to the fluctuation, correct the speed on the control side using the speed correction signal, and in the case of a control abnormality, use on-off control to return the free loop to its normal position. In a free loop control device for strip material that uses a digital arithmetic and control device, two optical detectors are installed above and below to sandwich the lower end of the free loop during automatic operation. When one detector operates twice in a row, the time interval T _s from the previous operation is measured, and the reference side speed detection coefficient K ₁ or the control side speed is determined according to the measured time interval T _s . A free loop control method for strip material, characterized in that the detection coefficient _K2 is corrected, and the corrected speed detection coefficient is used to perform automatic speed control on the control side.