A method for controlling the shearing position and speed of cold continuous rolling strip steel

Abstract

The present invention provides a method for controlling the shearing position and speed of cold continuous rolling strip steel, including a position control model and a speed control model; in the position control model, the position setting ΔS is the sum of the first position setting and the second position setting, and is input into the first PI controller to complete the position closed-loop control; the first position setting is calculated by the position calculation model, and the second position setting is the original position of the flying shear angle; in the speed control model, the speed setting ΔV is the sum of the first speed setting and the second speed setting, and is input into the second PI controller to complete the speed closed-loop control; the first speed setting is obtained from the speed calculation model; the second speed setting is the control result output by the position control model. For different strip steel conditions, the double closed-loop control of the shearing position and speed of cold continuous rolling strip steel is realized, and the speed control based on the precise positioning of each cycle of the flying shear operation can be achieved, which plays a crucial role in improving the production efficiency of cold continuous rolling.

Description

Technical Field

[0001] The present invention relates to the technical field of rolling process control, and in particular to a method for controlling shearing position and speed of cold continuous rolling strip steel. Background Art

[0002] The flying shear is a key piece of equipment at the exit of a tandem cold mill. Located between the exit pinch rolls and the coiler, it is the sole actuator for automatically shearing the continuously rolled cold strip. It is driven by an AC variable-frequency motor. To minimize the impact on the strip's continuous rolling process, the shear position must be precise and consistent with the preselected shear position. The shearing process involves high-speed, high-precision slitting of the moving strip to the required length. The flying shear control system involves numerous control functions and complex logic. It achieves high-precision strip shearing, ensuring both strip shearing and the absence of overlapping shear seams. By designing a dual closed-loop control method for strip shear position and speed, the flying shear can achieve precise positioning during each cycle of operation, enabling control of accelerated start-up, uniform cutting speed, and deceleration and stopping. This plays a crucial role in improving production efficiency in tandem cold milling.

[0003] In the prior art, Chinese Patent Publication No. CN105382331A discloses a flying shear control method. This method primarily designs a method for calculating the total speed of the flying shear during continuous shearing. However, this patent lacks coordination between control functions during shearing and calculation of the flying shear rotation angle. Chinese Patent Publication No. CN103962384A discloses a dynamic shear control method for hot-rolled strip steel. This method primarily utilizes a transfer function control approach to achieve dynamic strip shearing. This patent is implemented under hot-rolled conditions, significantly different from dynamic shear control under cold-rolled conditions. As described above, in the actual control process, due to the involvement of the strip shearing control process, controlling the running speed of the strip directly affects the strip shearing control. The key to influencing the running speed of the strip before shearing lies in the precise positioning of the strip. Furthermore, the specifications of the incoming strip can also make shearing precision control difficult. Controlling the shear position at different shearing speeds also presents problems as the strip running speed varies. If this affects the shearing performance of the flying shear, it will affect the control of the strip yield rate. Summary of the Invention

[0004] In order to solve the technical problems raised by the background technology, the present invention provides a method for controlling the shearing position and speed of cold-rolled strip steel. According to different strip conditions, dual closed-loop control of the shearing position and speed of cold-rolled strip steel is realized, and speed control based on precise positioning of each cycle of the flying shear operation can be achieved, which plays a vital role in improving the production efficiency of cold rolling.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for controlling shearing position and speed of cold rolled strip steel, comprising a position control model and a speed control model;

[0007] In the position control model, the position setting ΔS is the sum of the first position setting and the second position setting, which is then compared with the actual position of the flying shear and input into the first PI controller to complete the position closed-loop control; the first position setting is calculated by the position calculation model, and the second position setting is the original position of the flying shear angle;

[0008] In the speed control model, the speed setting ΔV is the sum of the first speed setting and the second speed setting, which is then compared with the actual speed of the flying shear and input into the second PI controller to complete the speed closed-loop control; the first speed setting is obtained by the speed calculation model; the second speed setting is the control result output by the position control model.

[0009] Furthermore, the position calculation model includes the following:

[0010]

[0011] Where Sx pos1 is the first position setting, k is the hysteresis factor of shear velocity, SB REST Remaining strip length, SH shear blade speed increase length, Fsx pos1 Position impact factor;

[0012] in, or

[0013] Where H is the waiting shear position, θ CA is the shear angle, R is the shear drum radius;

[0014] in,

[0015] Where h is the thickness of the strip, MUE is the shear blade overlap;

[0016]

[0017] Where i is the gear ratio of the shear reducer.

[0018] Furthermore, the second position includes a plurality of positions: the flying shear angle initial position pos1, the belt threading position pos2, the waiting position pos3, and the shear blade inspection position pos4, and one of them is selected.

[0019] Furthermore, the following speed calculation model is set according to different second positions:

[0020]

[0021]

[0022]

[0023] Vx pos4 = k * V s * Fvx pos4

[0024] In the formula, Vx pos1 , Vx pos2 , Vx pos3 , Vx pos4 are respectively the first speed setting values when the second position is the initial position pos1 of the flying shear angle, the threading position pos2, the waiting position pos3, and the shear blade inspection position pos4;

[0025] V s is the strip speed, αx is the actual shear blade angle, k ST is the limit of the shear speed hysteresis factor, Fvx posi is the adaptive speed factor at position i, k is the hysteresis factor of the shear speed, SB REST is the remaining strip length, SH is the shear blade acceleration length;

[0026] In the formula, H is the waiting shear position, θ CA is the shear angle, R is the shear drum radius;

[0027] Among them,

[0028] In the formula, h is the strip thickness, MUE is the shear blade overlap;

[0029] b is the reduction gear tooth ratio, Fvx pos4 takes an empirical constant.

[0030] Furthermore, it also includes a torque control model. The first speed setting input torque setting model calculates the torque setting ΔM. ΔM is summed with the output of the speed controller and compared with the actual torque value, and the deviation value is input to the torque controller to complete the torque control.

[0031] Furthermore, the torque setting model includes the following:

[0032] First torque setting: Frictional torque: The first speed setting is obtained through a piecewise linear friction curve;

[0033] Second torque setting: Accelerating torque:

[0034]

[0035] In the formula, J0 is the transmission fixed torque, JC Torque based on position, i is the gear ratio, V s is the strip speed, h is the strip thickness, R is the radius of the shear drum, dV s / dt is the strip acceleration.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] Taking the flying shear at the exit of the tandem cold rolling mill as the research object, the application of the double closed-loop control method of shear position and speed can greatly improve the shear control accuracy of the strip. Shear control is the prerequisite and guarantee for the tandem cold rolling mill to achieve high-precision strip shear control. Each step in the shear control process has very strict conversion conditions. The present invention can achieve speed control based on the precise positioning of each cycle of the flying shear operation, which plays a crucial role in improving the production efficiency of the tandem cold rolling. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is the control block diagram of a method for controlling the shear position and speed of a strip in a tandem cold rolling mill according to the present invention;

[0039] Figure 2 is the friction curve graph of the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] The following provides a detailed description of the specific embodiments provided by the present invention in conjunction with the accompanying drawings.

[0041] As Figure 1 shown, a method for controlling the shear position and speed of a strip in a tandem cold rolling mill includes a position control model and a speed control model; it also includes a torque setting model.

[0042] In the position control model described above, the position setting ΔS is the sum of the first position setting and the second position setting, and then compared with the actual position of the flying shear, and input into the first PI controller to complete the position closed-loop control; the first position setting is the shear length value, which is calculated by the position calculation model, and the second position setting is the original position of the flying shear angle.

[0043] In the speed control model described above, the speed setting ΔV is the sum of the first speed setting and the second speed setting, and then compared with the actual speed of the flying shear, and input into the second PI controller to complete the speed closed-loop control; the first speed setting is obtained from the speed calculation model; the second speed setting is the control result output by the position control model.

[0044] In the torque control model described above, the first speed setting is input into the torque setting model to calculate the torque setting ΔM, ΔM is summed with the output of the speed controller and compared with the actual torque value, and the deviation value is input into the torque controller to complete the torque control.

[0045] I. Position Control Model:

[0046] The described position calculation model is as follows:

[0047]

[0048] In the formula, Sx pos1 is the first position setting, k is the hysteresis factor of the shear speed (1.0 - 1.1), SB REST is the remaining strip length, SH is the shear blade acceleration length, Fsx pos1 is the position influence factor;

[0049] Among them, or

[0050] In the formula, H is the waiting shear position, θ CA is the shear angle, and R is the shear drum radius;

[0051] Among them,

[0052] In the formula, h is the strip thickness, and MUE is the shear blade overlap;

[0053]

[0054] The described second position includes multiple positions: the flying shear angle initial position pos1, the threading position pos2, the waiting position pos3, and the shear blade inspection position pos4. Select one of them.

[0055] The position setting ΔS is the sum of the first position setting and the second position setting, and then compared with the actual position of the flying shear, and input into the first PI controller to complete the position closed-loop control; the first position setting is the shear length value, calculated by the position calculation model, and the second position setting is the original position of the flying shear angle.

[0056] II. Speed Control Model:

[0057] Set the following speed calculation models according to different second positions:

[0058]

[0059]

[0060]

[0061] Vx pos4 = k * V s * Fvx pos4

[0062] In the formula, Vx pos1 、Vxpos2 、Vx pos3 、Vx pos4 are the first speed setting values when the second position is at the initial position pos1 of the flying shear angle, threading position pos2, waiting position pos3, and shear blade inspection position pos4 respectively;

[0063] V s is the strip speed, αx is the actual shear blade angle, k ST is the limit of the shear speed hysteresis factor, Fvx posi is the adaptive speed factor at position i, k is the hysteresis factor of the shear speed, SB REST is the remaining strip length, SH is the shear blade acceleration length;

[0064] In the formula, H is the waiting shear position, θ CA is the shear angle, R is the radius of the shear drum;

[0065] Among them,

[0066] In the formula, h is the strip thickness, MUE is the shear blade overlap;

[0067] Fvx pos4 = 0.13, b is the gear ratio of the reducer.

[0068] The speed setting ΔV is the sum of the first speed setting and the second speed setting, and then compared with the actual speed of the flying shear, and input into the second PI controller to complete the speed closed-loop control; the first speed setting is obtained from the speed calculation model; the second speed setting is the control result output by the position control model.

[0069] III. Torque control model

[0070] The torque setting model includes the following:

[0071] First torque setting: Frictional torque: The first speed setting is obtained through a piecewise linear friction curve; see the friction curve in Figure 2 .

[0072] Second torque setting: Accelerating torque:

[0073]

[0074] In the formula, J0 is the fixed transmission torque, J C is the torque based on the position, i is the gear ratio, V s is the strip speed, h is the strip thickness, R is the radius of the shear drum, dV s / dt is the strip acceleration.

[0075] The first speed setting inputs the torque setting model to calculate the torque setting ΔM. ΔM is summed with the output of the speed controller and compared with the actual torque value. The deviation value is input to the torque controller (PI controller) to complete the torque control. Specific embodiments

[0077] The automatic shearing control of the flying shear is mainly completed by the cooperation of line coordination, master speed, and strip tracking functions in the basic automation of tandem cold rolling. During normal rolling, the flying shear stops at the waiting position (initial position), that is, the initial position of the flying shear angle pos1 (140° in this embodiment), and may also be at the threading position pos2 (50°), waiting position pos3, and shear blade inspection position pos4, each corresponding to different angle values.

[0078] Define the shearing point as 6m in front of the weld (this data is used to determine SB REST the remaining strip length and H is the waiting shearing position).

[0079] Strip speed control: When the strip tracking calculates that the distance from the shearing point to the entrance of the stand is (5 ± 0.5m), send a signal that the shearing point is on the line to the line coordination, and require the strip to decelerate to the shearing speed.

[0080] The first position setting Sx pos1 :

[0081]

[0082] In the formula, k is the hysteresis factor of the shearing speed. This variable is used to reduce the interaction between the flying shear and the strip during shearing. In this embodiment, the empirical value 0.148 is taken, SB REST the remaining strip length, SH is the shear blade acceleration length, Fsx pos1 position influence factor;

[0083] Among them, or

[0084] In the formula, H is the waiting shearing position, 330° in this embodiment, θ CA is the shearing angle, and R is the radius of the shear drum;

[0085] Among them,

[0086] In the formula, h is the strip thickness, and MUE is the shear blade overlap;

[0087]

[0088] The second position is the first speed setting value when the flying shear angle is at the initial position pos1:

[0089]

[0090] In the formula, V s is the strip speed, k is the hysteresis factor of the shearing speed, SB REST is the remaining strip length, SH is the blade acceleration length;

[0091] b is the reduction gear ratio.

[0092] The above embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation manners and specific operation processes are given, but the protection scope of the present invention is not limited to the above embodiments. The methods used in the above embodiments are all conventional methods unless otherwise specified.

Claims

1. A method for controlling the shearing position and speed of cold continuous rolling strip steel, characterized in that, It includes a position control model and a speed control model; In the described position control model, the position setpoint ΔS is the sum of the first position setpoint and the second position setpoint, and then it is compared with the actual position of the flying shear. The first PI controller is input to complete the position closed-loop control; the first position setpoint is calculated by the position calculation model, and the second position setpoint is the original position of the flying shear angle; In the described speed control model, the speed setpoint ΔV is the sum of the first speed setpoint and the second speed setpoint, and then it is compared with the actual speed of the flying shear. The second PI controller is input to complete the speed closed-loop control; the first speed setpoint is obtained from the speed calculation model; the second speed setpoint is the control result output by the position control model; The described position calculation model includes the following: ； In the formula, is the first position setting, k is the hysteresis factor of the shear speed, remaining strip length, shearing blade acceleration length, position influence factor; Among them, or ; where H is the waiting shear position, is the shear angle, and R is the radius of the shear drum; Among them, ; In the formula, h is the strip thickness, and MUE is the shear blade overlap; 。 2. The cold tandem rolling strip steel shearing position and speed control method according to claim 1, characterized in that The described second position includes multiple positions: the initial position of the flying shear angle pos1, the threading position pos2, the waiting position pos3, and the shear blade inspection position pos4. One of them is selected.

3. A method for controlling the shearing position and speed of cold continuous rolling strip steel according to claim 1, characterized in that, Set the following speed calculation models according to different second positions: ； ； ； ； In the formula, , , , are the first speed setting values when the second position is at the initial position of the flying shear angle pos1, the threading position pos2, the waiting position pos3, and the shear blade inspection position pos4, respectively; is the strip speed, αx is the actual shear blade angle, k ST is the limit of the shear speed hysteresis factor, Fvx posi is the adaptive speed factor at position i, k is the hysteresis factor of the shear speed, remaining strip length, shear blade acceleration length; ； where \(i = 1 - 3\), \(b\) is the reduction ratio of the reducer, taking the empirical constant, \(R\) is the radius of the shear drum.

4. A method for controlling the shearing position and speed of cold continuous rolling strip steel according to claim 1, characterized in that, It also includes a torque control model. The first speed setpoint is input to the torque setpoint model to calculate the torque setpoint ΔM. ΔM is summed with the output of the speed controller and compared with the actual torque value. The deviation value is input to the torque controller to complete the torque control.

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