A method for controlling the transmission speed during dynamic specification changes in a cold rolling mill

Abstract

This invention provides a method for controlling the transmission speed during dynamic specification change in a cold continuous rolling mill, relating to the field of electrical control technology for cold continuous rolling mills. This method involves: determining the speed control wedge adjustment coefficient for each mill stand during dynamic specification change; determining the total speed control wedge coefficient for each mill stand during dynamic specification change; determining the transmission speed coefficient for each mill stand based on the strip speed coefficient before the wedge at the mill stand exit, the total wedge coefficient of the transmission speed, and the forward slip coefficient before the wedge; determining the transmission speed setpoint for each mill stand based on the transmission speed coefficient and the exit strip speed setpoint of the main speed ramp; and sending the transmission speed setpoint for each mill stand to the corresponding frequency converter controller. The speed control of each mill stand transmission is achieved through closed-loop speed control by the frequency converter controller. This method can improve the control accuracy of speed and thickness in continuous rolling mills during dynamic specification change.

Description

Technical Field

[0001] This invention relates to the field of electrical control technology for cold rolling mills, and in particular to a method for controlling the transmission speed during dynamic specification changes in cold rolling mills. Background Technology

[0002] Typical cold rolling mill equipment layout is as follows Figure 1 As shown, its main components include mill inlet correction roller 1, mill inlet tension roller 2 (which is regarded as the 0# stand for thickness control in advanced flow control), 1-5# mill stands 4-8, mill outlet flying shear 11, mill outlet flying shear front pinch roller 10, mill outlet steering roller 12, coiler 13, as well as tension measuring roller 3, mill outlet plate shape roller 9 and other large instruments, transmission reduction gearbox 14, transmission motor 15, and transmission speed encoder 16.

[0003] Before the pickled cold-rolled strip 17 reaches the rolling mill, the centering of the strip 17 is ensured by the straightening roller 1 at the mill inlet; the tension roller 2 at the mill inlet is responsible for establishing the strip tension at the mill inlet, or participates in thickness control as the 0# stand; the 1-5# mill stands 4-8 achieve comprehensive control of the tension, thickness and speed of the target strip 17 by controlling the hydraulic pressing and the stand transmission speed, so that the strip 17 at the mill exit reaches the set thickness; the slitting or welding is completed at the flying shear 11 at the mill exit, and the finished strip 17 is wound into a steel coil by the coiler 13.

[0004] For cold continuous rolling mills, the strip thickness at the mill exit is the most important control objective. The secondary model distributes the load to each stand based on the raw strip thickness and the target thickness. By pre-calculating the proportional relationship between the strip speed at the mill inlet and the exit speed of each stand, thickness control is transformed into speed control.

[0005] Based on the secondary settings, the proportional coefficient (hereinafter referred to as the strip speed coefficient) between the strip speed at the mill inlet and the strip speed at the exit of each stand is calculated using the following formula (taking stand #1 as an example). This proportional coefficient clarifies the proportional relationship between each stand in eliminating strip thickness differences. Without manual intervention in the strip speed at the exit of each stand (i.e., manual adjustment of the load on each stand), this ratio remains constant. Thickness control and inter-stand tension control only involve fine-tuning each transmission speed based on this proportional coefficient.

[0006]

[0007] Wherein, PFX1 is the strip speed coefficient at the exit of stand 4 of rolling mill #1; VX SDH 1 The setpoint for the strip speed at exit 4 of the #1 rolling mill stand from the second stage; VX SDH 5The set value for the strip speed at the exit of the 8th stand of the 5th rolling mill from the second stage.

[0008] Based on the actual strip speed setpoint V_MR1 at the end of the last stand, the speed setpoint of the transmission for each stand is calculated using the strip speed coefficient at the exit of each stand and the forward slip setpoint of each stand. This enables the basic automation system to control the transmission speed. The calculation formula (taking stand 4 of rolling mill #1 as an example) is as follows:

[0009]

[0010] Wherein, VS1 is the speed setting value for drive 4 of stand 1 of rolling mill; V_MR1 is the strip speed setting value at the mill exit of the main speed ramp; PFX1 is the strip speed coefficient at the exit of stand 4 of rolling mill 1; SLA SDH 1 The forward sliding setting value for stand 4 of the No. 1 rolling mill from the second stage.

[0011] In continuous rolling processes, situations such as passing through weld seams, recalculating secondary setpoints, or threading thick strip heads require the use of wedge control for dynamic switching of rolling specifications. Figure 2 As shown. Before dynamic specification change, the secondary system sends the wedge parameters to the basic automation system, including: the starting position of the wedge region and the total length L_WDG_setp of the wedge region after each stand. When the starting position of the wedge region reaches stand 4 of rolling mill #1, wedge rolling is started. First, wedge tracking of stand 4 of rolling mill #1 is performed: the length value L_WDG_act1 of the wedge region after stand 4 of rolling mill #1 is calculated based on the speed of the strip after stand 4 of rolling mill #1, and the actual number of wedge steps WDG_STEP1 after stand 4 of rolling mill #1 is calculated using the following formula:

[0012]

[0013] Where L_WDG_setp1 is the total length of the wedge region from the second stage after passing through stand 4 of rolling mill #1; WDG_STEP_n is the total number of wedge steps (a fixed value, e.g., 20 steps). Then, the wedge coefficient WDG1 of stand 4 of rolling mill #1 is calculated using the following formula:

[0014]

[0015] If the length of the wedge region extending through mill stand 4 (1st mill) is greater than the distance between mill stand 4 (1st mill) and mill stand 5 (2nd mill) (i.e., the starting position of the wedge region reaches mill stand 5 (2nd mill), then wedge tracking on mill stand 5 (2nd mill) is triggered. The wedge rolling process from mill stand 5 (2nd mill) to mill stand 8 (5th mill) is similar to that of mill stand 4 (1st mill). If the actual number of wedge steps after mill stand 8 (5th mill) is greater than or equal to the set total number of steps, then the wedge rolling is complete.

[0016] This traditional wedge control method uses a single stand as the controlled object, generating a wedge coefficient (WDG) only when the wedge region reaches the stand. This is used for wedge transition control of the stand's reduction, speed, bending rolls, and skewed rolls. For continuous rolling mills, this control method fails to consider the impact of the wedge transition of the stand on the preceding and following stands, and therefore cannot be directly applied to continuous rolling mill control. Summary of the Invention

[0017] The purpose of this invention is to provide a method for controlling the transmission speed during dynamic specification changes in a cold continuous rolling mill. Based on the wedge coefficient, the changes in setpoints before and after wedge forming, and the mutual influence of the speed control of the front and rear stands, the method calculates the speed setpoints of all transmissions in the rolling mill zone during dynamic specification changes. This improves the control accuracy of the mill speed and thickness during dynamic specification changes, ensures the stability of the wedge forming process, reduces the probability of strip breakage, guarantees the stability of the unit, and improves production efficiency. The specific technical solution is as follows:

[0018] A method for controlling the transmission speed during dynamic specification change in a cold continuous rolling mill, the method comprising the following steps:

[0019] S100. Determine the speed control wedge adjustment coefficient of each mill stand during the dynamic specification change process: Based on the following wedge setting values, including the wedge coefficient of each mill stand, the strip thickness before and after the wedge at the inlet and outlet, the forward slip coefficient before and after the wedge, and the strip speed coefficient before and after the wedge at the outlet, determine the wedge adjustment coefficients of the strip speed at the inlet of each mill stand, the transmission speed of the mill stand, and the strip speed at the outlet of the mill stand.

[0020] S200. Determine the total speed control wedge coefficient for each mill stand during dynamic specification changes: Starting from the last mill stand, calculate the total wedge coefficient of the strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet for each mill stand in reverse order. For the last mill stand, the total wedge coefficient of its strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet is determined by the wedge adjustment coefficients of its strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet. For each mill stand before the last mill stand, the total wedge coefficient of its strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet is determined by the wedge adjustment coefficients of its strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet, and the wedge adjustment coefficients of the strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet for each mill stand after it.

[0021] S300. Determine the speed coefficient of the transmission of each mill stand based on the strip speed coefficient before the wedge at the exit of each mill stand, the total wedge coefficient of the transmission speed, and the forward slip coefficient before the wedge.

[0022] S400: Determine the speed setting value of each mill stand transmission based on the speed coefficient of each mill stand transmission and the exit strip speed setting value of the main speed ramp. Send the speed setting value of each mill stand transmission to the corresponding frequency converter controller. Realize the speed control of each mill stand transmission during dynamic specification change through the speed closed-loop control of the frequency converter controller.

[0023] Furthermore, in step S100, the calculation formulas for the wedge adjustment coefficients of the strip speed at the entrance of the final mill stand, the transmission speed of the mill stand, and the strip speed at the exit of the mill stand are as follows:

[0024]

[0025] Where K is the stage number of the last stand in a multi-stand cold rolling mill, FVH K FVS is the wedge adjustment coefficient for the strip speed at the entrance of the final mill stand. K FVX is the wedge adjustment coefficient for the transmission speed of the last stage rolling mill stand. K HNN is the wedge adjustment coefficient for the strip speed at the exit of the final mill stand. K HXN represents the strip thickness after the wedge shape at the entrance of the final mill stand. K SLN is the strip thickness after the wedge shape at the exit of the final mill stand. K The forward slip coefficient after the wedge shape of the last stage rolling mill stand; HNA K The strip thickness before the wedge at the entrance of the final mill stand; HXA K The strip thickness before the wedge at the exit of the final mill stand; SLA K PFXA is the forward slip coefficient before the wedge shape of the final mill stand. K PFXN is the strip speed coefficient before the wedge at the exit of the final mill stand. K WDG is the strip speed coefficient after the wedge shape at the exit of the final mill stand. K The wedge coefficient of the final stage rolling mill stand;

[0026] The calculation formulas for the wedge adjustment coefficients of the strip speed at the inlet of each mill stand before the final stage, the mill stand drive speed, and the strip speed at the outlet of the mill stand are as follows:

[0027]

[0028] FVX J =1.0

[0029] Where J is the stage number of each mill stand preceding the last stage of a multi-stand cold rolling mill, ranging from 1 to (K-1), FVH J FVS is the wedge adjustment coefficient for the strip speed at the inlet of each mill stand before the final stage. JFVX is the wedge adjustment coefficient for the transmission speed of each mill stand preceding the final stage; J HNN is the wedge adjustment coefficient for the strip speed exiting each mill stand before the final stage; J HXN represents the strip thickness after the wedge shape at the entrance of each mill stand before the final stage. J SLN represents the strip thickness after the wedge shape at the exit of each mill stand preceding the final stage. J The forward slip coefficient after the wedge shape of each mill stand before the final stage; HNA J HXA represents the strip thickness before the wedge at the entrance of each mill stand before the final stage. J SLA refers to the strip thickness before the wedge at the exit of each mill stand preceding the final stage. J WDG is the forward slip coefficient before the wedge shape of each mill stand preceding the final stage. J It represents the wedge coefficient of each mill stand preceding the final stage.

[0030] Furthermore, in step S200, the formula for calculating the total wedge coefficient of the strip speed at the entrance of the last stage rolling mill stand, the stand drive speed, and the strip speed at the exit is as follows:

[0031] WDG_H K =1.0×FVH K =FVH K

[0032] WDG_S K =1.0×FVS K =FVS K

[0033] WDG_X K =1.0×FVX K =FVX K

[0034] Among them, WDG_H K WDG_S is the total wedge coefficient representing the strip velocity at the entrance of the final mill stand. K The total wedge coefficient for the transmission speed of the last stage rolling mill stand; WDG_X K The total wedge coefficient for the strip velocity at the exit of the last mill stand;

[0035] The formula for calculating the total wedge coefficient of the strip speed at the inlet of each mill stand before the final stage, the mill drive speed, and the strip speed at the outlet is as follows:

[0036] WDG_H J =WDG_H J+1 ×FVH J =FVH K ×FVH K-1 ×…×FVHJ+1 ×FVH J

[0037] WDG_S J =WDG_H J+1 ×FVS J =FVH K ×FVH K-1 ×…×FVH J+1 ×FVS J

[0038] WDG_X J =WDG_H J+1 ×FVX J =FVH K ×FVH K-1 ×…×FVH J+1 ×FVX J

[0039] Among them, WDG_H J WDG_S is the total wedge coefficient for the strip velocity at the inlet of each mill stand preceding the final stage. J WDG_X is the total wedge coefficient for the transmission speed of each mill stand preceding the final stage; J It is the total wedge coefficient for the strip velocity at the exit of each mill stand before the final stage.

[0040] Furthermore, in step S300, the calculation formula for the speed coefficient of the final stage rolling mill stand drive is as follows:

[0041]

[0042] Among them, PFS WDG_K The speed coefficient of the final stage mill stand transmission during the wedge forming process;

[0043] The formulas for calculating the speed coefficients of the transmissions of each stage of the rolling mill stand before the final stage are as follows:

[0044]

[0045] Among them, PFS WDG_J PFXA represents the speed coefficient of the transmission of each stage of the rolling mill stand preceding the final stage during the wedge forming process. J SLA is the strip speed coefficient before the wedge at the exit of each mill stand preceding the final stage. J It is the forward slip coefficient of each stage of the rolling mill stand before the wedge shape.

[0046] Furthermore, in step S400, the calculation formula for the speed setpoint of the final stage rolling mill stand drive is as follows:

[0047]

[0048] Among them, VS WDG_K V_MR1 is the speed setting value for the final stage mill stand drive during the wedge forming process; V_MR1 is the exit strip speed setting value for the main speed ramp.

[0049] The calculation formulas for the speed setpoints of the mill stand drives before the final stage are as follows:

[0050]

[0051] Among them, VS WDG_J This refers to the speed setting value of each stage of the rolling mill stand drive before the final stage during the wedge forming process.

[0052] Furthermore, the strip speed coefficient at the exit of the final mill stand is determined based on the strip speed coefficient before the wedge at the exit of the final mill stand and the total wedge coefficient of the exit strip speed. The speed setting value of the drive after the final mill stand is determined based on the strip speed coefficient at the exit of the final mill stand and the exit strip speed setting value of the main speed ramp. The speed setting value of the drive after the final mill stand is sent to the frequency converter controller of the corresponding drive. The speed control of the drive after the final mill stand is realized through the speed closed-loop control of the frequency converter controller during the dynamic specification change process.

[0053] Furthermore, the formula for calculating the strip speed coefficient at the exit of the final mill stand is as follows:

[0054] PFX WDG _ K =PFXA K ×WDG_X K =PFXA K ×FVX K

[0055] Among them, PFX WDG_K The strip speed coefficient at the exit of the last mill stand during the wedge forming process;

[0056] The formula for calculating the speed setpoint of the drive after the last stage rolling mill stand is as follows:

[0057] VX WDG_K =V_MR1×PFX WDG_K =V_MR1×PFXA K ×FVX K

[0058] Among them, VX WDG_K This is the speed setting value for the drive after the last stage mill stand during the wedge forming process.

[0059] Furthermore, this also includes determining the wedge adjustment coefficients for the inlet strip speed, transmission speed, and outlet strip speed of the mill inlet tension roll during dynamic specification changes; determining the total speed control wedge coefficient of the mill inlet tension roll during dynamic specification changes: its total wedge coefficients for the inlet strip speed, transmission speed, and outlet strip speed are determined by the wedge adjustment coefficients for its inlet strip speed, transmission speed, and outlet strip speed, and the wedge adjustment coefficients for the inlet strip speed, mill stand transmission speed, and mill stand outlet strip speed of each subsequent mill stand; determining the speed coefficient of the mill inlet tension roll transmission based on the strip speed coefficient before wedge formation at the mill inlet tension roll outlet, the total wedge coefficient of the transmission speed, and the forward slip coefficient before wedge formation; determining the speed setting value of the mill inlet tension roll transmission based on the speed coefficient of the mill inlet tension roll transmission and the outlet strip speed setting value of the main speed ramp, and sending the speed setting value of the mill inlet tension roll transmission to the corresponding transmission frequency converter, thereby realizing speed control of the mill inlet tension roll transmission during dynamic specification changes through the speed closed-loop control of the frequency converter.

[0060] Furthermore, the wedge adjustment coefficients for the inlet strip speed, drive speed, and outlet strip speed of the mill inlet tension roll are as follows:

[0061] FVH0 = 1.0

[0062] FVS0 = 1.0

[0063] FVX0 = 1.0

[0064] Wherein, FVH0 is the wedge adjustment coefficient for the strip speed at the mill inlet tension roll; FVS0 is the wedge adjustment coefficient for the transmission speed of the mill inlet tension roll; and FVX0 is the wedge adjustment coefficient for the strip speed at the mill inlet tension roll outlet.

[0065] The formula for calculating the total wedge coefficient of the inlet strip speed, drive speed, and outlet strip speed of the mill inlet tension roll is as follows:

[0066] WDG_H0=WDG_H1×FVH0=FVH K ×FVH K-1 ×…×FVH J ×…×FVH2×FVH1×FVH0

[0067] WDG_S0 = WDG_H1 × FVS0 = FVH K ×FVH K-1 ×…×FVH J ×…×FVH2×FVH1×FVS0

[0068] WDG_X0 = WDG_H1 × FVX0 = FVH K ×FVHK-1 ×…×FVH J ×…×FVH2×FVH1×FVX0

[0069] Wherein, WDG_H0 is the total wedge coefficient of the strip speed at the inlet tension roll of the mill; WDG_S0 is the total wedge coefficient of the transmission speed of the inlet tension roll of the mill; WDG_X0 is the total wedge coefficient of the strip speed at the outlet tension roll of the mill.

[0070] The formula for calculating the speed coefficient of the tension roll drive at the mill inlet is as follows:

[0071]

[0072] Among them, PFS WDG_0 PFXA0 is the speed coefficient of the mill inlet tension roll drive during the wedge forming process; PFXA0 is the strip speed coefficient before wedge forming at the mill inlet tension roll outlet; SLA0 is the forward slip coefficient of the mill inlet tension roll before wedge forming, which is always 1.0.

[0073] The formula for calculating the speed setpoint of the mill inlet tension roll drive is as follows:

[0074] VS WDG_0 =V_MR1×PFS WDG_0 =V_MR1×PFXA0×FVH5×FVH4×FVH3×FVH2×FVH1

[0075] Among them, VS WDG_0 This is the speed setting value for the tension roll drive at the mill inlet during the wedge forming process.

[0076] Furthermore, the cold rolling mill is a five-stand cold rolling mill.

[0077] The present invention provides a method for controlling the transmission speed during dynamic specification changes in a cold continuous rolling mill, which has the following beneficial effects:

[0078] (1) This invention determines the wedge adjustment coefficients for the inlet strip speed, stand drive speed, and outlet strip speed of each stand based on the wedge coefficient and wedge setting values ​​such as the strip thickness setting value at the inlet and outlet of the stand before and after the wedge, the forward sliding setting value, and the strip speed coefficient at the stand outlet. Starting from the last mill stand, the total wedge coefficient for the inlet strip speed, stand drive speed, and outlet strip speed of each stand is determined in reverse order. When determining the total wedge coefficient for this stand, the influence of the wedge control of the subsequent stand on its inlet strip speed is taken into account. The total wedge coefficient is used to determine the wedge adjustment coefficients for the drive speed of each stand. The speed coefficient is calculated based on the speed setpoint of all drives in the rolling mill area. This speed setpoint is then sent to the frequency converter of the corresponding drive. The speed control of the drive during dynamic specification change is achieved through the closed-loop speed control of the frequency converter. Since the influence of the wedge control of the rear stand on the speed control of this stand is fully considered when calculating the wedge coefficient of the speed control of each stand, the calculation accuracy of the rolling mill speed setpoint during the unstable transition of dynamic specification change is improved, ensuring the stability of the unit speed control, reducing the probability of strip breakage, and improving the stability of the unit.

[0079] (2) Moreover, by calculating the wedge coefficients of the strip speed at the stand entrance, the transmission speed of the stand, and the strip speed at the stand exit during the dynamic specification change process, the relationship between the transmission speed and strip speed of the control object - the mill zone - is more intuitive and more conducive to process optimization in the production process.

[0080] (3) In addition, this control method is well adapted to the current mainstream cold rolling mill control concept. The control idea is clear and the calculation process is complete, so that the speed control of the mill transmission during dynamic specification change is well realized through basic automation control. Attached Figure Description

[0081] Figure 1 This is a typical equipment layout diagram of a cold rolling mill.

[0082] Figure 2 This is a schematic diagram of wedge control.

[0083] Figure 3 This is a flowchart illustrating the method for controlling the transmission speed during dynamic specification changes in a cold rolling mill.

[0084] Figure 4 This is a schematic diagram of the wedge speed control of the transmission during dynamic specification changes.

[0085] In the diagram: 1-Mill inlet straightening roll; 2-Mill inlet tension roll; 3-Tension measuring roll; 4-Mill #1 stand; 5-Mill #2 stand; 6-Mill #3 stand; 7-Mill #4 stand; 8-Mill #5 stand; 9-Mill exit strip roll; 10-Mill exit flying shear front pinch roll; 11-Mill exit flying shear; 12-Mill exit steering roll; 13-Coiler; 14-Drive reduction gearbox; 15-Drive motor; 16-Drive speed encoder; 17-Cold rolled strip. Detailed Implementation

[0086] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clearly illustrate the purpose of the embodiments of the present invention.

[0087] This embodiment provides a method for controlling the transmission speed during dynamic specification changes in a cold rolling mill. (See reference...) Figure 3 As shown, the method includes the following steps:

[0088] S100. Determine the speed control wedge adjustment coefficient of each mill stand during the dynamic specification change process: Based on the following wedge setting values, including the wedge coefficient of each mill stand, the strip thickness before and after the wedge at the inlet and outlet, the forward slip coefficient before and after the wedge, and the strip speed coefficient before and after the wedge at the outlet, determine the wedge adjustment coefficients of the strip speed at the inlet of each mill stand, the transmission speed of the mill stand, and the strip speed at the outlet of the mill stand.

[0089] S200. Determine the total speed control wedge coefficient for each mill stand during dynamic specification changes: Starting from the last mill stand, calculate the total wedge coefficient of the strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet for each mill stand in reverse order. For the last mill stand, the total wedge coefficient of its strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet is determined by the wedge adjustment coefficients of its strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet. For each mill stand before the last mill stand, the total wedge coefficient of its strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet is determined by the wedge adjustment coefficients of its strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet, and the wedge adjustment coefficients of the strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet for each mill stand after it.

[0090] S300. Determine the speed coefficient of the transmission of each mill stand based on the strip speed coefficient before the wedge at the exit of each mill stand, the total wedge coefficient of the transmission speed, and the forward slip coefficient before the wedge.

[0091] S400: Determine the speed setting value of each mill stand transmission based on the speed coefficient of each mill stand transmission and the exit strip speed setting value of the main speed ramp. Send the speed setting value of each mill stand transmission to the corresponding frequency converter controller. Realize the speed control of each mill stand transmission during dynamic specification change through the speed closed-loop control of the frequency converter controller.

[0092] This invention, in its embodiments, determines the wedge adjustment coefficients for the inlet strip speed, stand drive speed, and outlet strip speed of each stand based on wedge coefficients and wedge setting values ​​such as strip thickness settings at the inlet and outlet of the stands before and after the wedge, forward sliding settings, and strip speed coefficient at the stand outlet. Starting from the last mill stand, the total wedge coefficient for the inlet strip speed, stand drive speed, and outlet strip speed of each stand is determined in reverse order. When determining the total wedge coefficient for this stand, the influence of the wedge control of the subsequent stand on its inlet strip speed is taken into account. The drive speed of each stand is then determined based on the total wedge coefficient. The speed coefficient is calculated based on the speed setpoints of all drives in the rolling mill area. These setpoints are then sent to the corresponding frequency converters (VDCs) for closed-loop speed control, enabling speed control during dynamic specification changes. By fully considering the impact of rear-stand wedge control on the speed control of the stand itself when calculating the wedge coefficients for each stand's speed control, the accuracy of the rolling mill speed setpoint calculation during the unstable transition of dynamic specification changes is improved. This ensures stable unit speed control, reduces the probability of strip breakage, and enhances unit stability. Furthermore, calculating the wedge coefficients for the strip speed at the stand entrance, the stand drive speed, and the stand exit speed during dynamic specification changes separately provides a more intuitive understanding of the relationship between the controlled objects—the rolling mill drive speed and the strip speed—and facilitates process optimization. Additionally, this control method aligns well with current mainstream cold rolling mill control concepts, offering a clear control approach and a complete calculation process, enabling effective speed control of the rolling mill drive during dynamic specification changes through basic automation control.

[0093] In one embodiment, the calculation formulas for the wedge adjustment coefficients of the strip speed at the entrance of the final mill stand, the mill stand drive speed, and the strip speed at the exit of the mill stand in step S100 are as follows:

[0094]

[0095] Where K is the stage number of the last stand in a multi-stand cold rolling mill, FVH K FVS is the wedge adjustment coefficient for the strip speed at the entrance of the final mill stand. K FVX is the wedge adjustment coefficient for the transmission speed of the last stage rolling mill stand. K HNN is the wedge adjustment coefficient for the strip speed at the exit of the final mill stand. KHXN represents the strip thickness after the wedge shape at the entrance of the final mill stand. K SLN is the strip thickness after the wedge shape at the exit of the final mill stand. K The forward slip coefficient after the wedge shape of the last stage rolling mill stand; HNA K The strip thickness before the wedge at the entrance of the final mill stand; HXA K The strip thickness before the wedge at the exit of the final mill stand; SLA K PFXA is the forward slip coefficient before the wedge shape of the final mill stand. K PFXN is the strip speed coefficient before the wedge at the exit of the final mill stand. K WDG is the strip speed coefficient after the wedge shape at the exit of the final mill stand. K The wedge coefficient of the final stage rolling mill stand;

[0096] The calculation formulas for the wedge adjustment coefficients of the strip speed at the inlet of each mill stand before the final stage, the mill stand drive speed, and the strip speed at the outlet of the mill stand are as follows:

[0097]

[0098] FVX I =1.0

[0099] Where J is the stage number of each mill stand preceding the last stage of a multi-stand cold rolling mill, ranging from 1 to (K-1), FVH J FVS is the wedge adjustment coefficient for the strip speed at the inlet of each mill stand before the final stage. J FVX is the wedge adjustment coefficient for the transmission speed of each mill stand preceding the final stage; J HNN is the wedge adjustment coefficient for the strip speed exiting each mill stand before the final stage; J HXN represents the strip thickness after the wedge shape at the entrance of each mill stand before the final stage. J SLN represents the strip thickness after the wedge shape at the exit of each mill stand preceding the final stage. J The forward slip coefficient after the wedge shape of each mill stand before the final stage; HNA J HXA represents the strip thickness before the wedge at the entrance of each mill stand before the final stage. J SLA refers to the strip thickness before the wedge at the exit of each mill stand preceding the final stage. J WDG is the forward slip coefficient before the wedge shape of each mill stand preceding the final stage. J It represents the wedge coefficient of each mill stand preceding the final stage.

[0100] In one embodiment, the formula for calculating the total wedge coefficient of the strip speed at the entrance of the last stage rolling mill stand, the stand drive speed, and the strip speed at the exit of the last stage rolling mill in step S200 is as follows:

[0101] WDG_H K =1.0×FVH K =FVH K

[0102] WDG_S K =1.0×FVS K =FVS K

[0103] WDG_X K =1.0×FVX K =FVX K

[0104] Among them, WDG_H K WDG_S is the total wedge coefficient representing the strip velocity at the entrance of the final mill stand. K The total wedge coefficient for the transmission speed of the last stage rolling mill stand; WDG_X K The total wedge coefficient for the strip velocity at the exit of the last mill stand;

[0105] The formula for calculating the total wedge coefficient of the strip speed at the inlet of each mill stand before the final stage, the mill drive speed, and the strip speed at the outlet is as follows:

[0106] WDG_H J =WDG_H J+1 ×FVH J =FVH K ×FVH K-1 ×…×FVH J+1 ×FVH J

[0107] WDG_S J =WDG_H J+1 ×FVS J =FVH K ×FVH K-1 ×…×FVH J+1 ×FVS J

[0108] WDG_X J =WDG_H J+1 ×FVX J =FVH K ×FVH K-1 ×…×FVH J+1 ×FVX J

[0109] Among them, WDG_H J WDG_S is the total wedge coefficient for the strip velocity at the inlet of each mill stand preceding the final stage. JWDG_X is the total wedge coefficient for the transmission speed of each mill stand preceding the final stage; J It is the total wedge coefficient for the strip velocity at the exit of each mill stand before the final stage.

[0110] In one embodiment, the formula for calculating the speed coefficient of the final stage rolling mill stand drive in step S300 is as follows:

[0111]

[0112] Among them, PFS WDG_K The speed coefficient of the final stage mill stand transmission during the wedge forming process;

[0113] The formulas for calculating the speed coefficients of the transmissions of each stage of the rolling mill stand before the final stage are as follows:

[0114]

[0115] Among them, PFS WDG_J PFXA represents the speed coefficient of the transmission of each stage of the rolling mill stand preceding the final stage during the wedge forming process. J SLA is the strip speed coefficient before the wedge at the exit of each mill stand preceding the final stage. J It is the forward slip coefficient of each stage of the rolling mill stand before the wedge shape.

[0116] In one embodiment, the calculation formula for the speed setpoint of the final stage rolling mill stand drive in step S400 is as follows:

[0117]

[0118] Among them, VS WDG_K V_MR1 is the speed setting value for the final stage mill stand drive during the wedge forming process; V_MR1 is the exit strip speed setting value for the main speed ramp.

[0119] The calculation formulas for the speed setpoints of the mill stand drives before the final stage are as follows:

[0120]

[0121] Among them, VS WDG_J This refers to the speed setting value of each stage of the rolling mill stand drive before the final stage during the wedge forming process.

[0122] In one embodiment, the strip speed coefficient at the exit of the final mill stand is determined based on the strip speed coefficient before the wedge at the exit of the final mill stand and the total wedge coefficient of the exit strip speed. The speed setting value of the drive after the final mill stand is determined based on the strip speed coefficient at the exit of the final mill stand and the exit strip speed setting value of the main speed ramp. The speed setting value of the drive after the final mill stand is sent to the frequency converter controller of the corresponding drive. The speed control of the drive after the final mill stand during the dynamic specification change process is realized through the speed closed-loop control of the frequency converter controller.

[0123] In one embodiment, the formula for calculating the strip speed coefficient at the exit of the final mill stand is as follows:

[0124] PFX WDG_K =PFXA K ×WDG_X K =PFXA K ×FVX K

[0125] Among them, PFX WDG_K The strip speed coefficient at the exit of the last mill stand during the wedge forming process;

[0126] The formula for calculating the speed setpoint of the drive after the last stage rolling mill stand is as follows:

[0127] VX WDG_K =V_MR1×PFX WDG_K =V_MR1×PFXA K ×FVX K

[0128] Among them, VX WDG_K This is the speed setting value for the drive after the last stage mill stand during the wedge forming process.

[0129] In one embodiment, the method further includes determining the wedge adjustment coefficients for the inlet strip speed, transmission speed, and outlet strip speed of the mill inlet tension roll during dynamic specification changes; determining the total speed control wedge coefficient of the mill inlet tension roll during dynamic specification changes: the total wedge coefficients for its inlet strip speed, transmission speed, and outlet strip speed are determined by the wedge adjustment coefficients for its inlet strip speed, transmission speed, and outlet strip speed, and the wedge adjustment coefficients for the inlet strip speed, transmission speed, and outlet strip speed of subsequent mill stands; determining the speed coefficient of the mill inlet tension roll transmission based on the strip speed coefficient before wedge formation at the mill inlet tension roll outlet, the total wedge coefficient of the transmission speed, and the forward slip coefficient before wedge formation; determining the speed setting value of the mill inlet tension roll transmission based on the speed coefficient of the mill inlet tension roll transmission and the outlet strip speed setting value of the main speed ramp; sending the speed setting value of the mill inlet tension roll transmission to the corresponding transmission frequency converter, and realizing speed control of the mill inlet tension roll transmission during dynamic specification changes through the speed closed-loop control of the frequency converter.

[0130] In one embodiment, the wedge adjustment coefficients for the inlet strip speed, drive speed, and outlet strip speed of the mill inlet tension roll are as follows:

[0131] FVH0 = 1.0

[0132] FVS0 = 1.0

[0133] FVX0 = 1.0

[0134] Wherein, FVH0 is the wedge adjustment coefficient for the strip speed at the mill inlet tension roll; FVS0 is the wedge adjustment coefficient for the transmission speed of the mill inlet tension roll; and FVX0 is the wedge adjustment coefficient for the strip speed at the mill inlet tension roll outlet.

[0135] The formula for calculating the total wedge coefficient of the inlet strip speed, drive speed, and outlet strip speed of the mill inlet tension roll is as follows:

[0136] WDG_H0=WDG_H1×FVH0=FVH K ×FVH K-1 ×…×FVH J ×…×FVH2×FVH1×FVH0

[0137] WDG_S0 = WDG_H1 × FVS0 = FVH K ×FVH K-1 ×…×FVH J ×…×FVH2×FVH1×FVS0

[0138] WDG_X0 = WDG_H1 × FVX0 = FVH K ×FVHK-1 ×…×FVH J ×…×FVH2×FVH1×FVX0

[0139] Wherein, WDG_H0 is the total wedge coefficient of the strip speed at the inlet tension roll of the mill; WDG_S0 is the total wedge coefficient of the transmission speed of the inlet tension roll of the mill; WDG_X0 is the total wedge coefficient of the strip speed at the outlet tension roll of the mill.

[0140] The formula for calculating the speed coefficient of the tension roll drive at the mill inlet is as follows:

[0141]

[0142] Among them, PFS WDG_0 PFXA0 is the speed coefficient of the mill inlet tension roll drive during the wedge forming process; PFXA0 is the strip speed coefficient before wedge forming at the mill inlet tension roll outlet; SLA0 is the forward slip coefficient of the mill inlet tension roll before wedge forming, which is always 1.0.

[0143] The formula for calculating the speed setpoint of the mill inlet tension roll drive is as follows:

[0144] VS WDG_0 =V_MR1×PFS WDG_0 =V_MR1×PFXA0×FVH5×FVH4×FVH3×FVH2×FVH1

[0145] Among them, VS WDG_0 This is the speed setting value for the tension roll drive at the mill inlet during the wedge forming process.

[0146] Exemplary embodiments

[0147] See Figure 4 As shown, taking a five-stand cold rolling mill as an example, this paper illustrates the specific process of controlling the transmission speed during dynamic specification changes in a cold rolling mill. When the cold rolling mill dynamically switches rolling specifications during the rolling process, the wedge transition zone reaches stand 4 of the No. 1 mill first (i.e., the speed wedge adjustment of stand 4 of the No. 1 mill starts first). However, since the speed of the strip and transmission in the entire rolling mill area is adjusted in reverse with the strip speed at the exit of stand 8 of the No. 5 mill as the reference, the wedge adjustment of the front stand will also be affected by the wedge control of the rear stand. Therefore, in the entire dynamic specification change process, the wedge coefficient of the speed of each stand must be calculated in reverse from stand 8 of the No. 5 mill.

[0148] 1. Wedge control of stand 8 of rolling mill #5

[0149] When the starting position of the wedge region reaches the 8th stand of the 5th rolling mill, wedge control of the 8th stand of the 5th rolling mill begins according to the wedge coefficient setting value WDG5. During the wedge control process of the 8th stand of the 5th rolling mill, the strip speed at its inlet, the transmission speed of the stand, and the strip speed at the stand outlet will all be affected by the wedge control and change.

[0150] The wedge adjustment coefficients for the inlet strip speed, stand drive speed, and outlet strip speed of stand 8 of rolling mill #5 are calculated as follows:

[0151]

[0152] Wherein, FVH5 is the wedge adjustment coefficient for the strip speed at the entrance of the No. 5 mill stand; FVS5 is the wedge adjustment coefficient for the transmission speed of the No. 5 mill stand; FVX5 is the wedge adjustment coefficient for the strip speed at the exit of the No. 5 mill stand; HNN5 is the strip thickness after wedge forming at the entrance of the No. 5 mill stand; HXN5 is the strip thickness after wedge forming at the exit of the No. 5 mill stand; SLN5 is the forward slip coefficient after wedge forming at the No. 5 mill stand; HNA5 is the strip thickness before wedge forming at the entrance of the No. 5 mill stand; HXA5 is the strip thickness before wedge forming at the exit of the No. 5 mill stand; SLA5 is the forward slip coefficient before wedge forming at the No. 5 mill stand; PFXA5 is the strip speed coefficient before wedge forming at the exit of the No. 5 mill stand; PFXN5 is the strip speed coefficient after wedge forming at the exit of the No. 5 mill stand; WDG5 is the wedge coefficient of the No. 5 mill stand.

[0153] Because there is no rear stand, the speed of stand 8 of rolling mill #5 is only affected by its own wedge control. Therefore, during the dynamic specification change process, the total wedge coefficient of the inlet strip speed, stand drive speed, and outlet strip speed of stand 8 of rolling mill #5 is calculated as follows:

[0154] WDG_H5 = 1.0 × FVH5 = FVH5

[0155] WDG_S5 = 1.0 × FVS5 = FVS5

[0156] WDG_X5 = 1.0 × FVX5 = FVX5

[0157] Wherein, WDG_H5 is the total wedge coefficient of the strip speed at the entrance of the No. 5 mill stand; WDG_S5 is the total wedge coefficient of the transmission speed of the No. 5 mill stand; WDG_X5 is the total wedge coefficient of the strip speed at the exit of the No. 5 mill stand; FVH5 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 5 mill stand; FVS5 is the wedge adjustment coefficient of the transmission speed of the No. 5 mill stand; and FVX5 is the wedge adjustment coefficient of the strip speed at the exit of the No. 5 mill stand.

[0158] Therefore, the strip speed coefficient at the exit of the No. 5 rolling mill stand during the dynamic specification change process is calculated as follows:

[0159] PFX WDG_5 =PFXA5×WDG_X5=PFXA5×FVX5

[0160] Among them, PFX WDG_5 PFXA5 is the strip speed coefficient at the exit of the No. 5 mill stand during the wedge forming process; WDG_X5 is the total wedge coefficient of the strip speed at the exit of the No. 5 mill stand; and FVX5 is the wedge adjustment coefficient of the strip speed at the exit of the No. 5 mill stand.

[0161] The speed coefficient of the No. 5 rolling mill stand drive during the dynamic specification change process is calculated as follows:

[0162]

[0163] Among them, PFS WDG_5 PFXA5 is the speed coefficient of the No. 5 mill stand transmission during the wedge forming process; PFXA5 is the strip speed coefficient before wedge forming at the exit of the No. 5 mill stand; WDG_S5 is the total wedge forming coefficient of the transmission speed of the No. 5 mill stand; SLA5 is the forward slip coefficient before wedge forming of the No. 5 mill stand; FVS5 is the wedge forming adjustment coefficient of the transmission speed of the No. 5 mill stand.

[0164] Calculation of speed setpoint for the 1.5# rolling mill stand drive

[0165] During the dynamic specification change process, the speed setpoint of the No. 5 mill stand drive changes due to the influence of the speed coefficient of the No. 5 mill stand drive, as calculated below:

[0166]

[0167] Among them, VS WDG_5 V_MR1 is the speed setting value for the No. 5 mill stand drive during the wedge forming process; V_MR1 is the exit strip speed setting value for the main speed ramp; PFS WDG_5 PFXA5 is the speed coefficient of the No. 5 mill stand transmission during the wedge forming process; SLA5 is the strip speed coefficient before wedge forming at the exit of the No. 5 mill stand; FVS5 is the forward slip coefficient before wedge forming of the No. 5 mill stand; and FVS5 is the wedge adjustment coefficient of the transmission speed of the No. 5 mill stand.

[0168] Calculation of the speed setpoint for the drive behind the #2.5 rolling mill stand

[0169] Throughout the rolling process, the operating speed of the drive downstream of the No. 5 mill stand remains consistent with the strip speed at the exit of the No. 5 mill stand. Therefore, during dynamic specification changes, the speed setpoint of the drive downstream of the No. 5 mill stand changes due to the influence of the strip speed coefficient at the exit of the No. 5 mill stand, as calculated below:

[0170] VX WDG_5 =V_MR1×PFX WDG_5 =V_MR1×PFXA5×FVX5

[0171] Among them, VX WDG_5 The strip speed setting at the exit of the No. 5 mill stand during the wedge forming process is the same as the speed setting of the drive after the No. 5 mill stand; V_MR1 is the strip speed setting at the exit of the main speed ramp; PFX WDG 5 PFXA5 is the strip speed coefficient at the exit of the No. 5 mill stand during the wedge forming process; FVX5 is the strip speed coefficient before wedge forming at the exit of the No. 5 mill stand; FVX5 is the wedge adjustment coefficient for the strip speed at the exit of the No. 5 mill stand.

[0172] II. Wedge control of No. 4 rolling mill stand

[0173] When the starting position of the wedge region reaches the 4# mill stand 7, wedge control of the 4# mill stand 7 begins according to the wedge coefficient setting value WDG4. During the wedge control process of the 4# mill stand 7, the strip speed at its inlet, the transmission speed of the stand, and the strip speed at the stand outlet will all be affected by the wedge control and change.

[0174] The wedge adjustment coefficients for the inlet strip speed, stand drive speed, and outlet strip speed of stand 7 of rolling mill #4 are calculated as follows:

[0175]

[0176]

[0177] FVX4 = 1.0

[0178] Wherein, FVH4 is the wedge adjustment coefficient for the strip speed at the entrance of the No. 4 mill stand; FVS4 is the wedge adjustment coefficient for the transmission speed of the No. 4 mill stand; FVX4 is the wedge adjustment coefficient for the strip speed at the exit of the No. 4 mill stand; HNN4 is the strip thickness after wedge forming at the entrance of the No. 4 mill stand; HXN4 is the strip thickness after wedge forming at the exit of the No. 4 mill stand; SLN4 is the forward slip coefficient after wedge forming at the No. 4 mill stand; HNA4 is the strip thickness before wedge forming at the entrance of the No. 4 mill stand; HXA4 is the strip thickness before wedge forming at the exit of the No. 4 mill stand; SLA4 is the forward slip coefficient before wedge forming at the No. 4 mill stand; and WDG4 is the wedge coefficient of the No. 4 mill stand.

[0179] When wedge control is applied to stand 8 of rolling mill #5, it affects the strip speed at its inlet, indirectly affecting the speed of stand 7 of rolling mill #4. Therefore, during the dynamic specification change process, the total wedge coefficient for the strip speed at the inlet, stand drive speed, and strip speed at the outlet of stand 7 of rolling mill #4 is calculated as follows:

[0180] WDG_H4=WDG_H5×FVH4=FVH5×FVH4

[0181] WDG_S4=WDG_H5×FVS4=FVH5×FVS4

[0182] WDG_X4=WDG_H5×FVX4=FVH5×FVX4

[0183] Wherein, WDG_H4 is the total wedge coefficient of the strip speed at the entrance of the No. 4 mill stand; WDG_S4 is the total wedge coefficient of the transmission speed of the No. 4 mill stand; WDG_X4 is the total wedge coefficient of the strip speed at the exit of the No. 4 mill stand; WDG_H5 is the total wedge coefficient of the strip speed at the entrance of the No. 5 mill stand; FVH5 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 5 mill stand; FVH4 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 4 mill stand; FVS4 is the wedge adjustment coefficient of the transmission speed of the No. 4 mill stand; and FVX4 is the wedge adjustment coefficient of the strip speed at the exit of the No. 4 mill stand.

[0184] Therefore, the strip speed coefficient at the exit of the No. 4 rolling mill stand during the dynamic specification change process is calculated as follows:

[0185] PFX WDG_4 =PFXA4×WDG_X4=PFXA4×FVH5×FVX4

[0186] Among them, PFX WDG_4 PFXA4 is the strip speed coefficient at the exit of the No. 4 mill stand during the wedge forming process; WDG_X4 is the total wedge coefficient of the strip speed at the exit of the No. 4 mill stand; FVH5 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 5 mill stand; and FVX4 is the wedge adjustment coefficient of the strip speed at the exit of the No. 4 mill stand.

[0187] The speed coefficient of the No. 4 rolling mill stand drive during the dynamic specification change process is calculated as follows:

[0188]

[0189] Among them, PFS WDG_4PFXA4 is the speed coefficient of the No. 4 mill stand transmission during the wedge forming process; PFXA4 is the strip speed coefficient before wedge forming at the exit of the No. 4 mill stand; WDG_S4 is the total wedge forming coefficient of the transmission speed of the No. 4 mill stand; SLA4 is the forward slip coefficient before wedge forming of the No. 4 mill stand; FVH5 is the wedge forming adjustment coefficient of the strip speed at the entrance of the No. 5 mill stand; FVS4 is the wedge forming adjustment coefficient of the transmission speed of the No. 4 mill stand.

[0190] Calculation of speed setpoint for the #1.4 rolling mill stand drive

[0191] During the dynamic specification change process, the speed setpoint of the No. 4 mill stand drive changes due to the influence of the speed coefficient of the No. 4 mill stand drive, as calculated below:

[0192]

[0193] Among them, VS WDG_4 V_MR1 is the speed setting value for the No. 4 mill stand drive during the wedge forming process; V_MR1 is the exit strip speed setting value for the main speed ramp; PFS WDG 4 PFXA4 is the speed coefficient of the No. 4 mill stand transmission during the wedge forming process; SLA4 is the strip speed coefficient before wedge forming at the exit of the No. 4 mill stand; FVH5 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 5 mill stand; and FVS4 is the wedge adjustment coefficient of the transmission speed of the No. 4 mill stand.

[0194] III. Wedge control of stand 6 of rolling mill #3

[0195] Similar to the No. 4 mill stand, the wedge adjustment coefficients for the inlet strip speed, stand drive speed, and outlet strip speed of the No. 3 mill stand are calculated as follows:

[0196]

[0197] FVX3 = 1.0

[0198] Wherein, FVH3 is the wedge adjustment coefficient for the strip speed at the entrance of the No. 3 mill stand; FVS3 is the wedge adjustment coefficient for the transmission speed of the No. 3 mill stand; FVX3 is the wedge adjustment coefficient for the strip speed at the exit of the No. 3 mill stand; HNN3 is the strip thickness after wedge forming at the entrance of the No. 3 mill stand; HXN3 is the strip thickness after wedge forming at the exit of the No. 3 mill stand; SLN3 is the forward slip coefficient after wedge forming at the No. 3 mill stand; HNA3 is the strip thickness before wedge forming at the entrance of the No. 3 mill stand; HXA3 is the strip thickness before wedge forming at the exit of the No. 3 mill stand; SLA3 is the forward slip coefficient before wedge forming at the No. 3 mill stand; WDG3 is the wedge coefficient of the No. 3 mill stand.

[0199] Similarly, the wedge control of the No. 5 and No. 4 mill stands indirectly affects the speed of the No. 3 mill stand. Therefore, the total wedge coefficient for the inlet strip speed, stand drive speed, and outlet strip speed of the No. 3 mill stand is calculated as follows:

[0200] WDG_H3=WDG_H4×FVH3=FVH5×FVH4×FVH3

[0201] WDG_S3=WDG_H4×FVS3=FVH5×FVH4×FVS3

[0202] WDG_X3=WDG_H4×FVX3=FVH5×FVH4×FVX3

[0203] Wherein, WDG_H3 is the total wedge coefficient of the strip speed at the entrance of the No. 3 mill stand; WDG_S3 is the total wedge coefficient of the transmission speed of the No. 3 mill stand; WDG_X3 is the total wedge coefficient of the strip speed at the exit of the No. 3 mill stand; WDG_H4 is the total wedge coefficient of the strip speed at the entrance of the No. 4 mill stand; FVH5 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 5 mill stand; FVH4 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 4 mill stand; FVH3 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 3 mill stand; FVS3 is the wedge adjustment coefficient of the transmission speed of the No. 3 mill stand; and FVX3 is the wedge adjustment coefficient of the strip speed at the exit of the No. 3 mill stand.

[0204] Therefore, the strip speed coefficient at the exit of the No. 3 rolling mill stand is calculated as follows during the dynamic specification change process:

[0205] PFX WDG_3 =PFXA3×WDG_X3=PFXA3×FVH5×FVH4×FVX3

[0206] Among them, PFX WDG_3 PFXA3 is the strip speed coefficient at the exit of the No. 3 mill stand during the wedge forming process; WDG_X3 is the total wedge coefficient of the strip speed at the exit of the No. 3 mill stand; FVH5 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 5 mill stand; FVH4 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 4 mill stand; and FVX3 is the wedge adjustment coefficient of the strip speed at the exit of the No. 3 mill stand.

[0207] The speed coefficient of the No. 3 rolling mill stand transmission during the dynamic specification change process is calculated as follows:

[0208]

[0209] Among them, PFS WDG_3PFXA3 is the speed coefficient of the No. 3 mill stand drive during the wedge forming process; PFXA3 is the strip speed coefficient before wedge forming at the exit of the No. 3 mill stand; WDG_S3 is the total wedge forming coefficient of the No. 3 mill stand drive speed; SLA3 is the forward slip coefficient before wedge forming of the No. 3 mill stand; FVH5 is the wedge forming adjustment coefficient of the strip speed at the entrance of the No. 5 mill stand; FVH4 is the wedge forming adjustment coefficient of the strip speed at the entrance of the No. 4 mill stand; FVS3 is the wedge forming adjustment coefficient of the drive speed of the No. 3 mill stand.

[0210] Calculation of speed setpoint for the #1.3 rolling mill stand drive

[0211] During the dynamic specification change process, the speed setpoint of the No. 3 mill stand drive changes due to the influence of the speed coefficient of the No. 3 mill stand drive, as calculated below:

[0212]

[0213] Among them, VS WDG_3 V_MR1 is the speed setting value for the No. 3 mill stand drive during the wedge forming process; V_MR1 is the strip speed setting value at the exit of the main speed ramp; PFS WDG 3 PFXA3 is the speed coefficient of the No. 3 mill stand drive during the wedge forming process; SLA3 is the strip speed coefficient before wedge forming at the exit of the No. 3 mill stand; FVH5 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 5 mill stand; FVH4 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 4 mill stand; and FVS3 is the wedge adjustment coefficient of the drive speed of the No. 3 mill stand.

[0214] IV. Wedge control of stand 5 of rolling mill #2

[0215] Similar to stand 7 of rolling mill #4, the wedge adjustment coefficients for the inlet strip speed, stand drive speed, and outlet strip speed of rolling mill #2 are calculated as follows:

[0216]

[0217] FVX2 = 1.0

[0218] Wherein, FVH2 is the wedge adjustment coefficient for the strip speed at the entrance of the No. 2 mill stand; FVS2 is the wedge adjustment coefficient for the transmission speed of the No. 2 mill stand; FVX2 is the wedge adjustment coefficient for the strip speed at the exit of the No. 2 mill stand; HNN2 is the strip thickness after wedge forming at the entrance of the No. 2 mill stand; HXN2 is the strip thickness after wedge forming at the exit of the No. 2 mill stand; SLN2 is the forward slip coefficient after wedge forming at the No. 2 mill stand; HNA2 is the strip thickness before wedge forming at the entrance of the No. 2 mill stand; HXA2 is the strip thickness before wedge forming at the exit of the No. 2 mill stand; SLA2 is the forward slip coefficient before wedge forming at the No. 2 mill stand; WDG2 is the wedge coefficient of the No. 2 mill stand.

[0219] Similarly, the wedge control of stand 8 of rolling mill #5, stand 7 of rolling mill #4, and stand 6 of rolling mill #3 indirectly affects the speed of stand 5 of rolling mill #2. Therefore, the total wedge coefficient for the inlet strip speed, stand drive speed, and outlet strip speed of stand 5 of rolling mill #2 is calculated as follows:

[0220] WDG_H2=WDG_H3×FVH2=FVH3×FVH4×FVH3×FVH2

[0221] WDG_S2=WDG_H3×FVS2=FVH5×FVH4×FVH3×FVS2

[0222] WDG_X2=WDG_H3×FVX2=FVH5×FVH4×FVH3×FVX2

[0223] Wherein, WDG_H2 is the total wedge coefficient of the strip speed at the entrance of the No. 2 mill stand; WDG_S2 is the total wedge coefficient of the transmission speed of the No. 2 mill stand; WDG_X2 is the total wedge coefficient of the strip speed at the exit of the No. 2 mill stand; WDG_H3 is the total wedge coefficient of the strip speed at the entrance of the No. 3 mill stand; FVH5 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 5 mill stand; FVH4 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 4 mill stand; FVH3 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 3 mill stand; FVH2 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 2 mill stand; FVS2 is the wedge adjustment coefficient of the transmission speed of the No. 2 mill stand; and FVX2 is the wedge adjustment coefficient of the strip speed at the exit of the No. 2 mill stand.

[0224] Therefore, the strip speed coefficient at the exit of the No. 2 rolling mill stand is calculated as follows during the dynamic specification change process:

[0225] PFX WDG_2 =PFXA2×WDG_X2=PFXA2×FVH5×FVH4×FVH3×FVX2

[0226] Among them, PFX WDG_2PFXA2 is the strip speed coefficient at the exit of the #2 mill stand during the wedge forming process; WDG_X2 is the total wedge coefficient of the strip speed at the exit of the #2 mill stand before wedge forming; FVH5 is the wedge adjustment coefficient of the strip speed at the entrance of the #5 mill stand; FVH4 is the wedge adjustment coefficient of the strip speed at the entrance of the #4 mill stand; FVH3 is the wedge adjustment coefficient of the strip speed at the entrance of the #3 mill stand; and FVX2 is the wedge adjustment coefficient of the strip speed at the exit of the #2 mill stand.

[0227] The speed coefficient of the No. 2 rolling mill stand drive during the dynamic specification change process is calculated as follows:

[0228]

[0229] Among them, PFS WDG_2 PFXA2 is the speed coefficient of the No. 2 mill stand drive during the wedge forming process; PFXA2 is the strip speed coefficient before wedge forming at the exit of the No. 2 mill stand; WDG_S2 is the total wedge forming coefficient of the No. 2 mill stand drive speed; SLA2 is the forward slip coefficient before wedge forming of the No. 2 mill stand; FVH5 is the wedge forming adjustment coefficient of the strip speed at the entrance of the No. 5 mill stand; FVH4 is the wedge forming adjustment coefficient of the strip speed at the entrance of the No. 4 mill stand; FVH3 is the wedge forming adjustment coefficient of the strip speed at the entrance of the No. 3 mill stand; FVS2 is the wedge forming adjustment coefficient of the drive speed of the No. 2 mill stand.

[0230] Calculation of speed setpoint for the #1.2 rolling mill stand drive

[0231] During the dynamic specification change process, the speed setpoint of the No. 2 mill stand drive changes due to the influence of the speed coefficient of the No. 2 mill stand drive, as calculated below:

[0232]

[0233] Among them, VS WDG_2 V_MR1 is the speed setting value for the No. 2 mill stand drive during the wedge forming process; V_MR1 is the strip speed setting value at the exit of the main speed ramp; PFS WDG 2 PFXA2 is the speed coefficient of the No. 2 mill stand drive during the wedge forming process; SLA2 is the strip speed coefficient before wedge forming at the exit of the No. 2 mill stand; FVH5 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 5 mill stand; FVH4 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 4 mill stand; FVH3 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 3 mill stand; and FVS2 is the wedge adjustment coefficient of the drive speed of the No. 2 mill stand.

[0234] V. Wedge control of stand 4 of rolling mill #1

[0235] Similar to stand 7 of rolling mill #4, the wedge adjustment coefficients for the inlet strip speed, stand drive speed, and outlet strip speed of rolling mill #1 are calculated as follows:

[0236]

[0237]

[0238] FVX1 = 1.0

[0239] Wherein, FVH1 is the wedge adjustment coefficient for the strip speed at the entrance of the No. 1 mill stand; FVS1 is the wedge adjustment coefficient for the transmission speed of the No. 1 mill stand; FVX1 is the wedge adjustment coefficient for the strip speed at the exit of the No. 1 mill stand; HNN1 is the strip thickness after wedge forming at the entrance of the No. 1 mill stand; HXN1 is the strip thickness after wedge forming at the exit of the No. 1 mill stand; SLN1 is the forward slip coefficient after wedge forming at the No. 1 mill stand; HNA1 is the strip thickness before wedge forming at the entrance of the No. 1 mill stand; HXA1 is the strip thickness before wedge forming at the exit of the No. 1 mill stand; SLA1 is the forward slip coefficient before wedge forming at the No. 1 mill stand; WDG1 is the wedge coefficient of the No. 1 mill stand.

[0240] Similarly, the wedge control of stands 8 of rolling mill #5, 7 of rolling mill #4, 6 of rolling mill #3, and 5 of rolling mill #2 indirectly affects the speed of stand #1. Therefore, the total wedge coefficient for the inlet strip speed, stand drive speed, and outlet strip speed of stand #1 is calculated as follows:

[0241] WDG_H1=WDG_H2×FVH1=FVH5×FVH4×FVH3×FVH2×FVH1

[0242] WDG_S1=WDG_H2×FVS1=FVH5×FVH4×FVH3×FVH2×FVS1

[0243] WDG_X1=WDG_H2×FVX1=FVH5×FVH4×FVH3×FVH2×FVX1

[0244] Wherein, WDG_H1 is the total wedge coefficient of the strip speed at the entrance of the No. 1 mill stand; WDG_S1 is the total wedge coefficient of the transmission speed of the No. 1 mill stand; WDG_X1 is the total wedge coefficient of the strip speed at the exit of the No. 1 mill stand; WDG_H2 is the total wedge coefficient of the strip speed at the entrance of the No. 2 mill stand; FVH5 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 5 mill stand; FVH4 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 4 mill stand; FVH3 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 3 mill stand; FVH2 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 2 mill stand; FVH1 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 1 mill stand; FVS1 is the wedge adjustment coefficient of the transmission speed of the No. 1 mill stand; and FVX1 is the wedge adjustment coefficient of the strip speed at the exit of the No. 1 mill stand.

[0245] Therefore, the strip speed coefficient at the exit of the No. 1 mill stand during the dynamic specification change process is calculated as follows:

[0246] PFX WDG_1 =PFXA1×WDG_X1=PFXA1×FVH5×FVH4×FVH3×FVH2×FVX1

[0247] Among them, PFX WDG_1 PFXA1 is the strip speed coefficient at the exit of the No. 1 mill stand during the wedge forming process; WDG_X1 is the total wedge coefficient of the strip speed at the exit of the No. 1 mill stand; FVH5 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 5 mill stand; FVH4 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 4 mill stand; FVH3 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 3 mill stand; FVH2 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 2 mill stand; and FVX1 is the wedge adjustment coefficient of the strip speed at the exit of the No. 1 mill stand.

[0248] During the dynamic specification change process, the speed coefficient of the No. 1 rolling mill stand transmission is calculated as follows:

[0249]

[0250] Among them, PFS WDG_1PFXA1 is the speed coefficient of the No. 1 mill stand drive during the wedge forming process; WDG_S1 is the strip speed coefficient before wedge forming at the exit of the No. 1 mill stand; SLA1 is the total wedge forming coefficient of the No. 1 mill stand drive speed; FVH5 is the wedge forming adjustment coefficient of the strip speed at the entrance of the No. 5 mill stand; FVH4 is the wedge forming adjustment coefficient of the strip speed at the entrance of the No. 4 mill stand; FVH3 is the wedge forming adjustment coefficient of the strip speed at the entrance of the No. 3 mill stand; FVH2 is the wedge forming adjustment coefficient of the strip speed at the entrance of the No. 2 mill stand; FVS1 is the wedge forming adjustment coefficient of the drive speed of the No. 1 mill stand.

[0251] 1.1 Calculation of the speed setpoint for the rolling mill stand drive

[0252] During the dynamic specification change process, the speed setpoint of the No. 1 mill stand drive changes due to the influence of the speed coefficient of the No. 1 mill stand drive, as calculated below:

[0253]

[0254] Among them, VS WDG_1 V_MR1 is the speed setting value for the No. 1 mill stand drive during the wedge forming process; V_MR1 is the strip speed setting value at the exit of the main speed ramp; PFS WDG 1 PFXA1 is the speed coefficient of the No. 1 mill stand drive during the wedge forming process; SLA1 is the strip speed coefficient before wedge forming at the exit of the No. 1 mill stand; FVH5 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 5 mill stand; FVH4 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 4 mill stand; FVH3 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 3 mill stand; FVH2 is the wedge adjustment coefficient of the strip speed at the entrance of the No. 2 mill stand; FVS1 is the wedge adjustment coefficient of the drive speed of the No. 1 mill stand.

[0255] 2. Calculation of the speed setting value of the tension roll 2 (0# mill stand) drive at the mill inlet

[0256] When the specifications change dynamically, the wedge-shaped region reaching the mill inlet tension roll 2 region (i.e., the mill inlet) will not cause changes in the strip speed and transmission speed. Therefore, the wedge adjustment coefficients for the inlet strip speed, transmission speed, and outlet strip speed of the mill inlet tension roll 2 are as follows:

[0257] FVH0 = 1.0

[0258] FVS0 = 1.0

[0259] FVX0 = 1.0

[0260] Wherein, FVH0 is the wedge adjustment coefficient for the strip speed at the mill inlet tension roll; FVS0 is the wedge adjustment coefficient for the transmission speed of the mill inlet tension roll; and FVX0 is the wedge adjustment coefficient for the strip speed at the mill inlet tension roll outlet.

[0261] The wedge control in the rolling mill zone indirectly affects the strip speed at the mill inlet and the drive speed. The total wedge coefficient for the inlet strip speed, drive speed, and outlet strip speed of the mill inlet tension roll is calculated as follows:

[0262] WDG_H0=WDG_H1×FVH0=FVH5×FVH4×FVH3×FVH2×FVH1×FVH0

[0263] WDG_S0=WDG_H1×FVS0=FVH5×FVH4×FVH3×FVH2×FVH1×FVS0

[0264] WDG_X0=WDG_H1×FVX0=FVH5×FVH4×FVH3×FVH2×FVH1×FVX0

[0265] Wherein, WDG_H0 is the total wedge coefficient for the strip speed at the mill inlet tension roll; WDG_S0 is the total wedge coefficient for the transmission speed of the mill inlet tension roll; WDG_X0 is the total wedge coefficient for the strip speed at the mill inlet tension roll outlet; WDG_H1 is the total wedge coefficient for the strip speed at the No. 1 mill stand inlet; FVH5 is the wedge adjustment coefficient for the strip speed at the No. 5 mill stand inlet; FVH4 is the wedge adjustment coefficient for the strip speed at the No. 4 mill stand inlet; FVH3 is the wedge adjustment coefficient for the strip speed at the No. 3 mill stand inlet; FVH2 is the wedge adjustment coefficient for the strip speed at the No. 2 mill stand inlet; FVH1 is the wedge adjustment coefficient for the strip speed at the No. 1 mill stand inlet; FVH0 is the wedge adjustment coefficient for the strip speed at the mill inlet tension roll; FVS0 is the wedge adjustment coefficient for the transmission speed of the mill inlet tension roll; and FVX0 is the wedge adjustment coefficient for the strip speed at the mill inlet tension roll outlet.

[0266] The effect of the mill inlet on the strip thickness can be ignored. It can be assumed that the inlet strip speed, the stand transmission speed and the outlet strip speed are completely equal. Therefore, only the transmission speed coefficient needs to be considered.

[0267] The speed coefficient of the mill inlet tension roll drive during dynamic specification changes is calculated as follows:

[0268]

[0269] Wherein, PFSWDG_0 is the speed coefficient of the mill inlet tension roll drive during the wedge forming process; PFXA0 is the strip speed coefficient before wedge forming at the mill inlet tension roll exit; WDG_S0 is the total wedge forming coefficient of the mill inlet tension roll drive speed; SLA0 is the forward slip coefficient of the mill inlet tension roll before wedge forming, constant at 1.0; FVH5 is the wedge forming adjustment coefficient of the strip speed at the inlet of the 5# mill stand; FVH4 is the wedge forming adjustment coefficient of the strip speed at the inlet of the 4# mill stand; FVH3 is the wedge forming adjustment coefficient of the strip speed at the inlet of the 3# mill stand; FVH2 is the wedge forming adjustment coefficient of the strip speed at the inlet of the 2# mill stand; FVH1 is the wedge forming adjustment coefficient of the strip speed at the inlet of the 1# mill stand; and FVS0 is the wedge forming adjustment coefficient of the mill inlet tension roll drive speed.

[0270] During dynamic specification changes, the speed setpoint of the mill inlet tension roll drive changes due to the influence of the speed coefficient of the mill inlet tension roll drive, as calculated below:

[0271] VS WDG_0 =V_MR1×PFS WDG_0 =V_MR1×PFXA0×FVH5×FVH4×FVH3×FVH2×FVH1

[0272] Among them, VS WDG_0 V_MR1 is the speed setting value for the mill inlet tension roll drive during the wedge forming process; V_MR1 is the strip speed setting value for the main speed ramp exit; PFS WDG_0 PFXA0 is the speed coefficient of the tension roll drive at the mill inlet during the wedge forming process; FVH5 is the wedge adjustment coefficient of the strip speed at the exit of the tension roll at the mill inlet before wedge forming; FVH4 is the wedge adjustment coefficient of the strip speed at the inlet of the #5 mill stand; FVH3 is the wedge adjustment coefficient of the strip speed at the inlet of the #4 mill stand; FVH2 is the wedge adjustment coefficient of the strip speed at the inlet of the #2 mill stand; FVH1 is the wedge adjustment coefficient of the strip speed at the inlet of the #1 mill stand; and FVS0 is the wedge adjustment coefficient of the tension roll drive speed at the mill inlet.

[0273] Those skilled in the art should understand that the present invention can be implemented in many other specific forms without departing from the spirit and scope of the invention. Any changes or modifications made by those skilled in the art based on the embodiments of the present invention and the above disclosure shall fall within the protection scope of the claims.

Claims

1. A method for controlling the transmission speed during dynamic specification change in a cold continuous rolling mill, characterized in that, The method includes the following steps: S100. Determine the speed control wedge adjustment coefficient of each mill stand during the dynamic specification change process: Based on the following wedge setting values, including the wedge coefficient of each mill stand, the strip thickness before and after the wedge at the inlet and outlet, the forward slip coefficient before and after the wedge, and the strip speed coefficient before and after the wedge at the outlet, determine the wedge adjustment coefficients of the strip speed at the inlet of each mill stand, the transmission speed of the mill stand, and the strip speed at the outlet of the mill stand. S200. Determine the total speed control wedge coefficient for each mill stand during dynamic specification changes: Starting from the last mill stand, calculate the total wedge coefficient of the strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet for each mill stand in reverse order. For the last mill stand, the total wedge coefficient of its strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet is determined by the wedge adjustment coefficients of its strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet. For each mill stand before the last mill stand, the total wedge coefficient of its strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet is determined by the wedge adjustment coefficients of its strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet, and the wedge adjustment coefficients of the strip speed at the inlet, the mill stand drive speed, and the strip speed at the outlet for each mill stand after it. S300. Determine the speed coefficient of the transmission of each mill stand based on the strip speed coefficient before the wedge at the exit of each mill stand, the total wedge coefficient of the transmission speed, and the forward slip coefficient before the wedge. S400: Determine the speed setting value of each mill stand transmission based on the speed coefficient of each mill stand transmission and the exit strip speed setting value of the main speed ramp. Send the speed setting value of each mill stand transmission to the corresponding frequency converter controller. Realize the speed control of each mill stand transmission during dynamic specification change through the speed closed-loop control of the frequency converter controller.

2. The method for controlling the transmission speed during dynamic specification change in a cold rolling mill according to claim 1, characterized in that, In step S100, the calculation formulas for the wedge adjustment coefficients of the strip speed at the entrance of the last-stage rolling mill stand, the transmission speed of the rolling mill stand, and the strip speed at the exit of the rolling mill stand are as follows: Where K is the stage number of the last stand in a multi-stand cold rolling mill, FVH K FVS is the wedge adjustment coefficient for the strip speed at the entrance of the final mill stand. K FVX is the wedge adjustment coefficient for the transmission speed of the last stage rolling mill stand. K HNN is the wedge adjustment coefficient for the strip speed at the exit of the final mill stand. K HXN represents the strip thickness after the wedge shape at the entrance of the final mill stand. K SLN is the strip thickness after the wedge shape at the exit of the final mill stand. K The forward slip coefficient after the wedge shape of the last stage rolling mill stand; HNA K The strip thickness before the wedge at the entrance of the final mill stand; HXA K The strip thickness before the wedge at the exit of the final mill stand; SLA K PFXA is the forward slip coefficient before the wedge shape of the final mill stand. K PFXN is the strip speed coefficient before the wedge at the exit of the final mill stand. K WDG is the strip speed coefficient after the wedge shape at the exit of the final mill stand. K The wedge coefficient of the final stage rolling mill stand; The calculation formulas for the wedge adjustment coefficients of the strip speed at the inlet of each mill stand before the final stage, the mill stand drive speed, and the strip speed at the outlet of the mill stand are as follows: FVX J =1.0 Where J is the stage number of each mill stand preceding the last stage of a multi-stand cold rolling mill, ranging from 1 to (K-1), FVH J FVS is the wedge adjustment coefficient for the strip speed at the inlet of each mill stand before the final stage. J FVX is the wedge adjustment coefficient for the transmission speed of each mill stand preceding the final stage; J HNN is the wedge adjustment coefficient for the strip speed exiting each mill stand before the final stage; J HXN represents the strip thickness after the wedge shape at the entrance of each mill stand before the final stage. J SLN represents the strip thickness after the wedge shape at the exit of each mill stand preceding the final stage. J The forward slip coefficient after the wedge shape of each mill stand before the final stage; HNA J HXA represents the strip thickness before the wedge at the entrance of each mill stand before the final stage. J SLA refers to the strip thickness before the wedge at the exit of each mill stand preceding the final stage. J WDG is the forward slip coefficient before the wedge shape of each mill stand preceding the final stage. J It represents the wedge coefficient of each mill stand preceding the final stage.

3. The method for controlling the transmission speed during dynamic specification change in a cold continuous rolling mill according to claim 2, characterized in that, In step S200, the formula for calculating the total wedge coefficient of the strip speed at the entrance of the last stage rolling mill stand, the stand drive speed, and the strip speed at the exit is as follows: WDG_H K =1.0×FVH K =FVH K WDG_S K =1.0×FVS K =FVS K WDG_X K =1.0×FVX K =FVX K Among them, WDG_H K WDG_S is the total wedge coefficient representing the strip velocity at the entrance of the final mill stand. K The total wedge coefficient for the transmission speed of the last stage rolling mill stand; WDG_X K The total wedge coefficient for the strip velocity at the exit of the last mill stand; The formula for calculating the total wedge coefficient of the strip speed at the inlet of each mill stand before the final stage, the mill drive speed, and the strip speed at the outlet is as follows: WDG_H J =WDG_H J+1 ×FVH J =FVH K ×FVH K-1 ×…×FVH J+1 ×FVH J WDG_S J =WDG_H J+1 ×FVS J =FVH K ×FVH K-1 ×…×FVH J+1 ×FVS J WDG_X J =WDG_H J+1 ×FVX J =FVH K ×FVH K-1 ×…×FVH J+1 ×FVX J Among them, WDG_H J WDG_S is the total wedge coefficient for the strip velocity at the inlet of each mill stand preceding the final stage. J WDG_X is the total wedge coefficient for the transmission speed of each mill stand preceding the final stage; J It is the total wedge coefficient for the strip velocity at the exit of each mill stand before the final stage.

4. The method for controlling the transmission speed during dynamic specification change in a cold continuous rolling mill according to claim 3, characterized in that, In step S300, the formula for calculating the speed coefficient of the final stage rolling mill stand drive is as follows: Among them, PFS WDG_K The speed coefficient of the final stage mill stand transmission during the wedge forming process; The formulas for calculating the speed coefficients of the transmissions of each stage of the rolling mill stand before the final stage are as follows: Among them, PFS WDG_J PFXA represents the speed coefficient of the transmission of each stage of the rolling mill stand preceding the final stage during the wedge forming process. J SLA is the strip speed coefficient before the wedge at the exit of each mill stand preceding the final stage. J It is the forward slip coefficient of each stage of the rolling mill stand before the wedge shape.

5. The method for controlling the transmission speed during dynamic specification change in a cold continuous rolling mill according to claim 4, characterized in that, In step S400, the calculation formula for the speed setpoint of the final stage rolling mill stand drive is as follows: Among them, VS WDG_K V_MR1 is the speed setting value for the final stage mill stand drive during the wedge forming process; V_MR1 is the exit strip speed setting value for the main speed ramp. The calculation formulas for the speed setpoints of the mill stand drives before the final stage are as follows: Among them, VS WDG_J This refers to the speed settings for the transmission of each stage of the rolling mill stand before the final stage during the wedge forming process.

6. The method for controlling the transmission speed during dynamic specification change in a cold rolling mill according to claim 5, characterized in that, The strip speed coefficient at the exit of the final mill stand is determined based on the strip speed coefficient before the wedge at the exit of the final mill stand and the total wedge coefficient of the exit strip speed. The speed setting value of the drive after the final mill stand is determined based on the strip speed coefficient at the exit of the final mill stand and the exit strip speed setting value of the main speed ramp. The speed setting value of the drive after the final mill stand is sent to the frequency converter controller of the corresponding drive. The speed control of the drive after the final mill stand is realized through the speed closed-loop control of the frequency converter controller during the dynamic specification change process.

7. The method for controlling the transmission speed during dynamic specification change in a cold rolling mill according to claim 6, characterized in that, The formula for calculating the strip speed coefficient at the exit of the last stage rolling mill stand is as follows: PFX WDG_K =PFXA K ×WDG_X K =PFXA K ×FVX K Among them, PFX WDG_K The strip speed coefficient at the exit of the last mill stand during the wedge forming process; The formula for calculating the speed setpoint of the drive after the last stage rolling mill stand is as follows: VX WDG_K =V_MR1×PFX WDG_K =V_MR1×PFXA K ×FVX K Among them, VX WDG_K This is the speed setting value for the drive after the last stage mill stand during the wedge forming process.

8. The method for controlling the transmission speed during dynamic specification change in a cold rolling mill according to claim 5, characterized in that, It also includes determining the wedge adjustment coefficients for the inlet strip speed, transmission speed, and outlet strip speed of the mill inlet tension roll during dynamic specification changes; The overall speed control wedge coefficient of the mill inlet tension roll during dynamic specification changes is determined as follows: the overall wedge coefficient of its inlet strip speed, transmission speed, and outlet strip speed is determined by the wedge adjustment coefficients of its inlet strip speed, transmission speed, and outlet strip speed, and the wedge adjustment coefficients of the inlet strip speed, transmission speed, and outlet strip speed of the subsequent mill stands. The speed coefficient of the mill inlet tension roll transmission is determined based on the strip speed coefficient before wedge formation at the mill inlet tension roll outlet, the overall wedge coefficient of the transmission speed, and the forward slip coefficient before wedge formation. The speed setting value of the mill inlet tension roll transmission is determined based on the speed coefficient of the mill inlet tension roll transmission and the outlet strip speed setting value of the main speed ramp. The speed setting value of the mill inlet tension roll transmission is sent to the frequency converter controller of the corresponding transmission. The speed control of the mill inlet tension roll transmission during dynamic specification changes is achieved through the speed closed-loop control of the frequency converter controller.

9. The method for controlling the transmission speed during dynamic specification change in a cold rolling mill according to claim 8, characterized in that, The wedge adjustment coefficients for the inlet strip speed, drive speed, and outlet strip speed of the mill inlet tension roll are as follows: FVH0 = 1.0 FVS0 = 1.0 FVX0 = 1.0 Wherein, FVH0 is the wedge adjustment coefficient for the strip speed at the mill inlet tension roll; FVS0 is the wedge adjustment coefficient for the transmission speed of the mill inlet tension roll; and FVX0 is the wedge adjustment coefficient for the strip speed at the mill inlet tension roll outlet. The formula for calculating the total wedge coefficient of the inlet strip speed, drive speed, and outlet strip speed of the mill inlet tension roll is as follows: WDG_H0=WDG_H1×FVH0=FVH K ×FVH K-1 ×…×FVH J ×…×FVH2×FVH1×FVH0 WDG_S0=WDG_H1×FVS0=FVH K ×FVH K-1 ×…×FVH J ×…×FVH2×FVH1×FVS0 WDG_X0 = WDG_H1 × FVX0 = FVH K ×FVH K-1 ×…×FVH J ×…×FVH2×FVH1×FVX0 where WDG_H0 is the total wedge coefficient of the strip speed at the mill inlet tension roll; WDG_S0 is the total wedge coefficient of the transmission speed of the mill inlet tension roll; WDG_X0 is the total wedge coefficient of the strip speed at the mill inlet tension roll outlet. The formula for calculating the speed coefficient of the tension roll drive at the mill inlet is as follows: Among them, PFS WDG_0 PFXA0 is the speed coefficient of the mill inlet tension roll drive during the wedge forming process; PFXA0 is the strip speed coefficient before wedge forming at the mill inlet tension roll outlet; SLA0 is the forward slip coefficient of the mill inlet tension roll before wedge forming, which is always 1.

0. The formula for calculating the speed setpoint of the mill inlet tension roll drive is as follows: VS WDG_0 =V_MR1×PFS WDG_0 =V_MR1×PFXA0×FVH5×FVH4×FVH3×FVH2×FVH1 Among them, VS WDG_0 This is the speed setting value for the tension roll drive at the mill inlet during the wedge forming process.

10. The method for controlling the transmission speed during dynamic specification change in a cold rolling mill according to any one of claims 1-9, characterized in that, The cold rolling mill is a five-stand cold rolling mill.

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