A precise control method based on load comparison between straightening machine and pinch roller

Abstract

The present invention discloses a precise control method based on load comparison between a straightening machine and a pinch roller, by real-time reading of the actual torque T of the straightening machine motor. 1 and the actual torque T of the pinch roller motor 2 , real-time calculation of the load rate T of the straightening machine motor 1 / T 1 e Load factor T of the pinch roller motor 2 / T 2 e ; When the actual torque T of the straightening machine motor 1 Less than the rated torque T of the straightening machine motor 1 e According to the load rate T of the straightening machine motor 1 / T 1 e Load factor T of the pinch roller motor 2 / T 2 e The size of the straightening machine motor is adjusted in real time to ensure that the load rate T of the straightening machine motor is always 1 / T 1 e Equal to the load rate T of the pinch roller motor 2 / T 2 e , to achieve accurate load balance between the straightener and the pinch roller. This method can accurately and automatically control the load balance between the straightener and the pinch roller, dynamically control in real time to reduce the damage to the pinch roller surface, avoid the straightener handle from breaking, extend the service life of the pinch roller, and improve the stability of the equipment.

Description

Technical Field

[0001] The present invention belongs to equipment in the unwinding area of ​​a finishing line, and in particular relates to a precise control method based on load comparison between a straightener and a pinch roller, and mainly relates to a tension distribution technology for tension pinch rollers, straighteners and unwinders of a finishing line. Background Art

[0002] In domestic and foreign steel enterprises, the uncoiling area of ​​the hot rolling finishing line uses entrance tension pinch rollers and entrance straighteners to balance the post-tension provided by the uncoiler equipment; in this type of system, the uncoiler is used as a torque control mode, and the pinch rollers and straighteners both use speed control mode. The pinch rollers and straighteners clamp the strip and provide tension for the strip together with the uncoiler.

[0003] like Figure 1 As shown in the figure, in the tension control of the unwinding area, the entrance tension pinch roller is mainly responsible for balancing the unwinding tension provided by the unwinding machine. If the tension provided by the unwinding machine is too large, the straightener provides a part of the balancing force. Since the unwinding tension changes with the product, the torque of the entrance tension pinch roller and the straightener needs to be adjusted with the change of the unwinding tension. In addition, with the change of production output, the roller diameter of the straightener and the roller diameter of the pinch roller will change due to wear, so the linear speed between the straightener pinch rollers will also change. This change will cause a slight pile-pulling phenomenon between the pinch rollers and the straightener, and cause the load of the straightener and the pinch rollers to be unbalanced. The strip tension provided by the unwinding machine will act on the pinch roller alone, causing damage to the roller surface of the pinch roller. Traditionally, the operator uses a potentiometer to compensate for the linear speed difference caused by the change of roller diameter, or the equipment maintenance personnel regularly measure the roller diameter value for correction. The main problems with the pinch roller control of the prior art are as follows: 1) Manual real-time adjustment is required: The traditional method of manually adjusting the entrance tension pinch roller and the load balance of the straightener requires the operator to be on duty in real time; 2) The error of manual adjustment is large, resulting in damage to the roller surface of the pinch roller or the breakage of the straightener handle: The error of manual adjustment is large, which often makes the single machine torque of one of the entrance tension pinch roller or the straightener too large, causing damage to the roller surface of the entrance pinch roller or the breakage of the straightener handle. Summary of the invention

[0004] In view of the above-mentioned defects existing in the prior art, the purpose of the present invention is to provide a precise control method based on the comparison of the loads of the straightening machine and the pinch roller, which can accurately and automatically control the load balance of the two equipments, the straightening machine and the pinch roller, and realize real-time dynamic control to reduce the damage to the roller surface of the pinch roller, avoid the straightening machine handle from twisting off, extend the service life of the pinch roller, and improve the stability of the equipment.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a precise control method based on the load comparison between the straightener and the pinch roller. After the strip enters the unwinding area of ​​the hot rolling finishing line, the actual torque T of the straightener motor is read in real time. 1 and the actual torque T of the pinch roller motor 2 , calculate the load rate T of the straightening machine motor in real time 1 / T 1 e The load factor T of the pinch roller motor 2 / T 2 e ; Among them, T 1 e is the rated torque of the straightening machine motor, T 2 e is the rated torque of the pinch roller motor;

[0007] When the actual torque T of the straightener motor 1 Less than the rated torque T of the straightening machine motor 1 e When the load rate T of the straightening machine motor is 1 / T 1 e The load factor T of the pinch roller motor 2 / T 2 e The size of the straightening machine motor is adjusted in real time to ensure that the load rate T of the straightening machine motor is always 1 / T 1 e Equal to the load rate T of the pinch roller motor 2 / T 2 e , achieving precise load balance between the straightening machine and the pinch rollers.

[0008] Preferably, the speed of the straightening machine motor is adjusted according to the following method:

[0009] When the load rate of the straightening machine is T 1 / T 1 e Less than the load rate T of the pinch roller motor 1 / T 1 e When , a compensation speed ΔS is added to the given speed value of the straightening machine motor, so that the straightening machine accelerates;

[0010] On the contrary, the speed setting value of the straightening machine motor is reduced by a compensation speed ΔS, so that the straightening machine is decelerated.

[0011] Preferably, the actual torque T of the straightening machine motor 1By reading the actual current I1 and actual magnetic flux Φ1 of the straightening machine motor, we can obtain:

[0012] T 1 =I1*Φ1

[0013] Among them, T 1 is the actual torque of the straightener motor, I1 is the actual current of the straightener motor, and Φ1 is the actual magnetic flux of the straightener motor.

[0014] Preferably, the actual torque T2 of the pinch roller motor is obtained by reading the actual current I2 and the actual magnetic flux Φ2 of the pinch roller motor:

[0015] T 2 =I2*Φ2

[0016] Among them, T 2 is the actual torque of the pinch roller motor, I2 is the actual current of the pinch roller motor, and Φ2 is the actual magnetic flux of the pinch roller motor.

[0017] Preferably, the lower limit of the compensation rotation speed ΔS is -5% of the maximum rotation speed of the straightener motor, and the upper limit of the compensation rotation speed ΔS is +5% of the maximum rotation speed of the straightener motor.

[0018] Preferably, the compensation rotation speed ΔS is additionally given by a negative balance controller.

[0019] Beneficial effects of the present invention:

[0020] 1. The precise control method based on the load comparison between the straightening machine and the pinch roller of the present invention can realize fully automatic precise load balance control without manual real-time adjustment and monitoring;

[0021] 2. The precise control method based on the load comparison between the straightening machine and the pinch roller of the present invention can dynamically control in real time to reduce the damage to the roller surface of the pinch roller, avoid the straightening machine handle from twisting off, greatly extend the service life of the pinch roller, and improve the stability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0023] Figure 1 It is a schematic diagram of the strip tension formed between the straightening machine, the pinch roll and the uncoiler in the uncoiling area of ​​the existing hot rolling finishing line;

[0024] Figure 2 It is a control principle block diagram of the precise control method based on the load comparison between the straightening machine and the pinch roller of the present invention;

[0025] Figure 3 It is a flow chart of the precise control method based on the load comparison between the straightening machine and the pinch roller of the present invention.

[0026] In the above drawings Figure 1 In the figure, 100, straightening machine; 200, pinch roller; 300, uncoiler; 1, straightening machine speed ramp; 2, adder; 3, straightening machine speed regulator; 4, straightening machine torque limiter; 5, adder; 6, straightening machine current regulator; 7, straightening machine trigger pulse; 8, straightening machine inverter; 9, multiplier; 10, straightening machine motor; 11, divider; 12, multiplier; 13, divider; 14, adder; 15, balance controller (proportional integrator); 16, pinch roller speed ramp Slope; 17. Adder; 18. Pinch roller speed regulator (proportional integrator); 19. Pinch roller torque limiter; 20. Adder; 21. Pinch roller current regulator (proportional integrator); 22. Pinch roller trigger pulse; 23. Pinch roller inverter; 24. Multiplier; 25. Pinch roller motor; 26. Negative balance controller; 400. Speed ​​and current dual closed-loop control system of straightening machine motor; 500. Speed ​​and current dual closed-loop control system of pinch roller motor; 600. PLC controller. DETAILED DESCRIPTION

[0027] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0028] Combination Figure 2 , Figure 3 As shown, the present invention provides a precise control method based on the load comparison between the straightening machine and the pinch roller. When the strip enters Figure 1 After the unwinding area of ​​the hot rolling finishing line shown in FIG. 1 , the PLC controller 600 reads the actual torque T of the straightening machine motor 10 in real time. 1 and the actual torque T of the pinch roller motor 25 2 , calculate the load rate T of the straightening machine motor 10 in real time 1 / T 1 e The load factor T of the pinch roller motor 25 2 / T 2 e ; Among them, T 1 e is the rated torque of the straightening machine motor 10, T 2 e is the rated torque of the pinch roller motor 25; when the actual torque T of the straightening machine motor 10 1 Less than the rated torque T of the straightening machine motor 10 1 e When, according to the load rate T of the straightening machine motor 10 1 / T1 e The load factor T of the pinch roller motor 25 2 / T 2 e The size of the straightening machine motor 10 is adjusted in real time to ensure that the load rate T of the straightening machine motor 10 is always 1 / T 1 e Equal to the load rate T of the pinch roller motor 25 2 / T 2 e , achieving precise load balance between the straightening machine 100 and the pinch roller 200.

[0029] The specific control steps are as follows:

[0030] (1) Read the actual torque T of the straightening machine motor 10 in real time 1 and the actual torque T of the pinch roller motor 25 2 ;

[0031] Combination Figure 2 As shown, in the speed and current dual closed-loop control system 400 of the straightening machine motor, the PLC controller 600 reads the actual current I1 and the actual magnetic flux Φ1 of the straightening machine motor 10 in real time through the inverter of the straightening machine motor 10, and obtains the actual torque T of the straightening machine motor 10. 1 :

[0032] T 1 =I1*Φ1

[0033] Among them, T 1 is the actual torque of the straightener motor 10, I1 is the actual current of the straightener motor 10, and Φ1 is the actual magnetic flux of the straightener motor 10.

[0034] Combination Figure 2 As shown, in the speed and current dual closed-loop control system 500 of the pinch roller motor, the PLC controller 600 reads the actual current I2 and the actual magnetic flux Φ2 of the pinch roller motor 25 in real time through the inverter of the pinch roller motor 25, and obtains the actual torque T of the straightening machine motor 10. 2 :

[0035] T 2 =I2*Φ2

[0036] Among them, T 2 is the actual torque of the pinch roller motor 25 , I2 is the actual current of the pinch roller motor 25 , and Φ2 is the actual magnetic flux of the pinch roller motor 25 .

[0037] (2) Calculating in real time the load rate of the straightening machine motor 10 and the load rate of the pinch roller motor 25;

[0038] Combination Figure 2 The load rate at a certain moment is obtained by the ratio of the actual torque at a certain moment to the rated torque. Since the load rate of the straightening machine motor 10 and the load rate of the pinch roller motor 25 need to be calculated in real time in the present invention, the actual torque T of the straightening machine motor 10 is calculated in real time. 1 and the rated torque T of the straightening machine motor 10 1 e The ratio of the load rate T of the straightening machine motor 10 is obtained. 1 / T 1 e Similarly, the actual torque T of the pinch roller motor 25 is calculated in real time 2 and the rated torque T of the pinch roller motor 25 2 e The load factor T of the pinch roller motor 25 is obtained by the ratio 2 / T 2 e ;

[0039] (3) Real-time determination of the actual torque T of the straightening machine motor 10 1 The rated torque T of the straightening machine motor 10 1 e The size of the straightening machine motor 10 is based on the load rate T 1 / T 1 e The load factor T of the pinch roller motor 25 2 / T 2 e The size of the straightening machine motor 10 is adjusted in real time to adjust the speed;

[0040] Combination Figure 2 , Figure 3 As shown, Figure 2 Among them, 1 to 10 constitute the speed and current double closed-loop control system 400 of the straightening machine motor, 16 to 25 constitute the speed and current double closed-loop control system 500 of the pinch roller motor, and 11 to 15 constitute the PLC controller 600.

[0041] Among them, combined Figure 2 As shown, in the PLC controller 600, the negative balance controller 26 (the negative balance controller 26 is composed of an adder 14 and a balance regulator 15) is given as the load rate of the pinch roller motor 25, and is fed back as the load rate of the straightening machine motor 10, which is adjusted in real time, and the output compensation speed ΔS is used as an additional given speed of the straightening machine motor 10; the compensation speed ΔS will change in real time with the adjustment of the balance controller 15 (proportional integrator), and in order to ensure stable adjustment, it is necessary to set upper and lower limits on the value of the compensation speed ΔS, and the lower limit of the compensation speed ΔS is -5% of the maximum speed of the straightening machine motor 10, and the upper limit of the compensation speed ΔS is +5% of the maximum speed of the straightening machine motor 10;

[0042] In this way, by adjusting the speed of the straightening machine motor 10 in real time, the load factor T of the straightening machine motor 10 is always ensured. 1 / T 1 e Equal to the load rate T of the pinch roller motor 25 2 / T 2 e , achieving precise load balance between the straightening machine 100 and the pinch roller 200.

[0043] Combination Figure 2 As shown, the PLC controller 600 reads the actual current I1 and the actual magnetic flux Φ1 from the inverter of the straightening machine motor 10, and multiplies I1 by Φ1 to calculate the actual torque T of the straightening machine motor 10. 1 The PLC controller 600 reads the actual current I2 and the actual magnetic flux Φ2 from the inverter of the pinch roller motor 25, and multiplies I2 by Φ2 to calculate the actual torque T of the pinch roller motor 25. 2 ; Then the actual torque T of the straightening machine motor 10 1 Divide by the rated torque T of the straightening machine motor 10 1 e Get the load rate T of the straightening machine motor 10 1 / T 1 e , multiplied by -1, and added to the adder 14 of the negative balance controller 26; the actual torque T of the pinch roller motor 25 2 Divide by the rated torque T of the pinch roller motor 25 2 e The load factor T of the pinch roller motor 25 is obtained as 1 / T 1 e The adder 14 attached to the negative balance controller 26 is adjusted in real time by the negative balance controller 26, and the output compensation speed ΔS is used as an additional given speed of the straightening machine motor 10. The compensation speed ΔS will change in real time with the adjustment of the balance controller (proportional integrator) 15; the control of the speed of the straightening machine motor 10 in the above process is achieved by adding the signal given by the negative balance regulator 26 to the speed and current dual closed-loop control system 400 of the straightening machine motor through the PLC controller 600; in this way, the load rate T of the straightening machine motor 10 can always be ensured. 1 / T 1 e Equal to the load rate T of the pinch roller motor 25 2 / T 2 e , achieving precise load balance between the straightening machine 100 and the pinch roller 200.

[0044] In summary, the precise control method based on load comparison between the straightening machine and the pinch roller of the present invention can not only realize fully automatic precise load balance control without manual real-time adjustment and monitoring, but also can realize real-time dynamic control to reduce the damage to the roller surface of the pinch roller and avoid the straightening machine handle from twisting off, thereby greatly extending the service life of the pinch roller and improving the stability of the equipment.

[0045] In domestic and foreign steel enterprises, hot rolling finishing lines use a large number of tension pinch rollers and straighteners to balance the tension applied by the uncoiler to the strip. When balancing the uncoiling tension of the finishing line, it is easy to cause steel piling between the pinch rollers and the straightener, and cause load imbalance between the straightener and the pinch rollers, resulting in damage to the surface of the pinch rollers. This is a common industry problem. The control method provided by the present invention can effectively avoid the above problems, while ensuring the stability of the surface quality of the strip, reducing the roller consumption of the pinch rollers and greatly extending the service life of the pinch rollers. It has great economic and social benefits for steel enterprises and has broad promotion value.

[0046] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A precise control method based on load comparison between a straightening machine and a pinch roller, characterized in that: After the strip enters the unwinding area of ​​the hot rolling finishing line, the actual torque T of the straightening machine motor is read in real time. 1 and the actual torque T of the pinch roller motor 2 , calculate the load rate T of the straightening machine motor in real time 1 / T 1 e The load factor T of the pinch roller motor 2 / T 2 e ; Among them, T 1 e is the rated torque of the straightening machine motor, T 2 e is the rated torque of the pinch roller motor; When the actual torque T of the straightener motor 1 Less than the rated torque T of the straightening machine motor 1 e When the load rate T of the straightening machine motor is 1 / T 1 e The load factor T of the pinch roller motor 2 / T 2 e The size of the straightening machine motor is adjusted in real time to ensure that the load rate T of the straightening machine motor is always 1 / T 1 e Equal to the load rate T of the pinch roller motor 2 / T 2 e , achieving precise load balance between the straightening machine and the pinch rollers, The speed of the straightening machine motor is adjusted according to the following method: When the load rate of the straightening machine is T 1 / T 1 e Less than the load rate T of the pinch roller motor 1 / T 1 e When , a compensation speed ΔS is added to the given speed value of the straightening machine motor, so that the straightening machine accelerates; On the contrary, the speed setting value of the straightening machine motor is reduced by a compensation speed ΔS, so that the straightening machine is decelerated. The actual torque T of the straightening machine motor 1 By reading the actual current I1 and actual magnetic flux Φ1 of the straightening machine motor, we can obtain: T 1 =I1*Φ1 Among them, T 1 is the actual torque of the straightening machine motor, I1 is the actual current of the straightening machine motor, Φ1 is the actual magnetic flux of the straightening machine motor, The actual torque T of the pinch roller motor 2 By reading the actual current I2 and actual magnetic flux Φ2 of the pinch roller motor, we can obtain: T 2 =I2*Φ2 Among them, T 2 is the actual torque of the pinch roller motor, I2 is the actual current of the pinch roller motor, and Φ2 is the actual magnetic flux of the pinch roller motor.

2. The precise control method based on load comparison between the straightening machine and the pinch roller according to claim 1, characterized in that: The lower limit of the compensation rotation speed ΔS is -5% of the maximum rotation speed of the straightening machine motor, and the upper limit of the compensation rotation speed ΔS is +5% of the maximum rotation speed of the straightening machine motor.

3. The precise control method based on load comparison between the straightening machine and the pinch roller according to claim 1, characterized in that: The compensation rotation speed ΔS is additionally given by a negative balance controller.

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