A control method and device for dynamically adjusting the frame load of a cold rolling mill

Abstract

The present invention discloses a control method and device for dynamically adjusting the rack load of a cold rolling mill. The method addresses overload issues caused by the rolling force, load factor, and rack speed of each rack in the cold rolling mill by calculating the outlet thickness setpoint adjustment and speed adjustment for each non-end rack. The present invention comprehensively considers various factors that can lead to rack load overload and utilizes shift registers to ensure coordinated adjustment of each rack. This method effectively and dynamically adjusts rack load, quickly returning it to a normal range, improving system stability and ensuring equipment and production safety.

Description

Technical Field

[0001] The present invention relates to the field of automatic control of a cold rolling mill, and in particular to a control method and device for dynamically adjusting a frame load of a cold rolling mill. Background Art

[0002] Properly distributing the roll-down load across each stand is a crucial component of cold rolling process control and forms the basis for calculating other setpoints. A mathematical model within the process computer, based on pre-prepared data, calculates the required roll-down loads for each stand during the actual strip rolling process, such as rolling force, forward slip, rolling torque, roll-down, and stand speed. These calculated, pre-set values ​​are then transmitted to the Level 1 basic automation system for strip rolling.

[0003] The secondary process control computer calculates the reduction and speed distribution for each stand in the cold rolling mill based on a pre-set model. The results are then fed into the power and rolling force models for verification. If the power or rolling force exceeds the limit, the calculation is repeated, and the cycle continues until both power and rolling force are within the limits. Therefore, the preset values ​​related to reduction load, such as thickness, rolling force, and power, sent to the primary basic automation system will not exceed the limits.

[0004] However, during the actual rolling process of a cold rolling mill, the actual load of each rack may deviate from the preset value or even exceed the rack's limit due to various reasons, such as excessive fluctuations in raw material thickness, large total strip reduction, or high rolling speed requirements. If not adjusted, the rack equipment may be damaged after a period of overload operation, and in serious cases, it may cause production accidents. Therefore, a control method for dynamically adjusting the rack load is required, which can be directly implemented in the first-level basic automation system. When a rack's load is detected to be outside the limit, the load is automatically adjusted to keep the load of each rack within a reasonable range. Summary of the Invention

[0005] The object of the present invention is to provide a control method and device for dynamically adjusting the frame load of a cold rolling mill, so as to keep the working load of each frame of the cold rolling mill within a limited range, ensure production safety and extend the service life of the equipment.

[0006] To solve the above technical problems, the present invention provides a technical solution: a control method for dynamically adjusting the rack load of a cold rolling mill, comprising the following steps:

[0007] S1. When the preset dynamic load adjustment enabling conditions of the cold rolling mill are met, executing subsequent steps;

[0008] S2. When the rolling force over-limit value of any non-head-end stand is greater than zero, the first thickness adjustment variation of each stand preceding the stand is accumulated according to the rolling force over-limit value of the stand; the rolling force over-limit value is the value at which the rolling force of a stand exceeds the maximum rolling force set for the stand;

[0009] S3. When the load rate over-limit value of any rack among the non-head-end racks is greater than zero, determining the second thickness adjustment change amount of the rack preceding the rack based on the load rate over-limit value of the rack; the load rate over-limit value is the value at which the load rate of a rack exceeds the maximum load rate set for the rack;

[0010] S4, summing the first thickness adjustment variation and the second thickness adjustment variation of the non-end rack and integrating the sum with respect to time to obtain a third thickness adjustment variation of the non-end rack;

[0011] S5. Obtaining a fourth thickness adjustment variation of the non-end rack by linear interpolation according to the rack speed of the non-end rack and a pre-stored numerical table;

[0012] S6. Adding the third thickness adjustment variation and the fourth thickness adjustment variation of the non-end rack to obtain a total thickness setting value adjustment; the total thickness setting value adjustment is used to correct the outlet thickness setting value of the non-end rack;

[0013] S7, according to the rack speed of the non-end rack, delay outputting the total adjustment amount of the thickness setting value of the non-end rack;

[0014] S8. Determine the frame speed correction amount of the non-end frame and the entrance tension roller according to the total adjustment amount of the thickness setting value outputted by the delay; the frame speed correction amount is used to correct the frame speed of the non-end frame and the entrance tension roller.

[0015] According to the above scheme, the enabling conditions for dynamic load adjustment of the cold rolling mill are:

[0016] 1) The preset load rate of the secondary process control system of the cold rolling mill is within the set range;

[0017] 2) The forward slip values ​​of all stands of the cold rolling mill are within the set normal range;

[0018] 3) The actual current value of the transmission motor of one or more stands of the cold rolling mill exceeds the first percentile of the maximum current value;

[0019] 4) The actual current values ​​of the transmission motors of all stands of the cold rolling mill exceed the second percentile of the maximum current value;

[0020] 5) The unit is not in the dynamic specification change period;

[0021] 6) There is no belt break signal or emergency stop signal in the unit;

[0022] When all the above conditions are met, it is considered that the dynamic load adjustment of the cold rolling mill is enabled.

[0023] According to the above scheme, step S2 includes:

[0024] S201, setting the default value of the first thickness adjustment variation of each rack to zero;

[0025] S202, determining a rolling force over-limit value according to the rolling force of the non-head end stand and the maximum rolling force;

[0026] S203. If there is a non-head-end stand with a rolling force over-limit value greater than zero, the first thickness adjustment changes of each stand before the stand are accumulated according to the rolling force over-limit value of the stand, the conversion factor of the rolling force of the stand to the outlet thickness, and the outlet thickness setting value of the stand before the stand.

[0027] According to the above scheme, S3 includes the following steps:

[0028] S301, setting the default value of the second thickness adjustment variation of each rack to zero;

[0029] S302: For a non-head-end rack having a load rate exceeding limit value greater than zero, determine a second thickness adjustment variation of a rack preceding the rack based on the load rate exceeding limit value of the rack and a conversion factor of the rack load rate to outlet thickness;

[0030] S303 , determining a second thickness adjustment variation of each non-end rack according to steps S301 and S302 .

[0031] According to the above scheme, step S4 includes the following steps:

[0032] S401, summing a first thickness adjustment variation and a second thickness adjustment variation of a non-end rack at a certain moment to obtain a first thickness adjustment integrated quantity of the rack at that moment;

[0033] S402, taking the ratio of the set sampling time and the set integration time parameter as a time coefficient;

[0034] S403, multiplying the first thickness adjustment integrated quantity by the time coefficient to obtain the second thickness adjustment integrated quantity at that moment;

[0035] S404, summing the second thickness adjustment integrated quantities at each previous moment to obtain the third thickness adjustment variation of the rack at the current moment;

[0036] S405 , determining the fourth thickness adjustment variation of each non-end rack according to steps S401 to S404 .

[0037] According to the above scheme, step S5 includes the following steps:

[0038] S501, pre-store a number of rack speed-fourth thickness adjustment change data points as a table;

[0039] S502: Read the rack speed of a non-end rack, and obtain the fourth thickness adjustment variation corresponding to the rack speed by linear interpolation based on the rack speed and a pre-stored data point of the rack speed-fourth thickness adjustment variation;

[0040] S503 : Determine the fourth thickness adjustment variation of each non-end rack according to steps S501 and S502 .

[0041] According to the above scheme, step S7 includes the following steps:

[0042] S701. For any non-end rack, determine a delay time of the rack based on the rack speed of the rack and the distance between the rack and the rack immediately following the rack.

[0043] S702: When the rack adjusts the outlet thickness of the rack according to the total adjustment amount of the thickness setting value, and the duration reaches the delay time, the total adjustment amount of the thickness setting value of the rack is output with a delayed time;

[0044] S703 , according to step S701 to step S702 , outputting the total adjustment amount of the thickness setting value of each rack in the non-end rack with a delayed output.

[0045] According to the above scheme, step S8 includes the following steps:

[0046] S801. For any non-end rack, determine a rack speed correction value for the rack based on a total thickness setting value adjustment value of a rack immediately following the rack, a total thickness setting value adjustment value of a delayed output of the rack, and a rack speed correction value of the rack immediately following the rack.

[0047] S802, determining a rack speed correction value for each rack in the non-end rack according to step S801;

[0048] S803: Determine the frame speed correction amount of the entrance tension roller according to the frame speed correction amount of the head end frame and the total adjustment amount of the thickness setting value.

[0049] The present invention also provides a control module for dynamically adjusting the rack load of a cold rolling mill, comprising:

[0050] The dynamic load regulation enabling judgment module is used to activate the subsequent modules to execute corresponding steps when the preset dynamic load regulation enabling conditions of the cold rolling mill are met;

[0051] a first thickness adjustment variation calculation module, configured to accumulate first thickness adjustment variations of each stand preceding the stand according to the rolling force excess value of the stand when the rolling force excess value of any stand among the non-head-end stands is greater than zero; the rolling force excess value is the value at which the rolling force of a stand exceeds the maximum rolling force set for the stand;

[0052] a second thickness adjustment variation calculation module configured to determine, when a load rate exceeding limit value of any non-head-end rack is greater than zero, a second thickness adjustment variation of a rack preceding the rack based on the load rate exceeding limit value of the rack; the load rate exceeding limit value being the value at which the load rate of a rack exceeds a maximum load rate set for the rack;

[0053] a third thickness adjustment variation calculation module, configured to sum the first thickness adjustment variation and the second thickness adjustment variation of the non-end rack and then integrate the sum over time to obtain a third thickness adjustment variation of the non-end rack;

[0054] a fourth thickness adjustment variation calculation module, configured to obtain a fourth thickness adjustment variation of the non-end rack by linear interpolation based on the rack speed of the non-end rack and a pre-stored numerical table;

[0055] a thickness setting value total adjustment amount calculation module, configured to add the third thickness adjustment variation and the fourth thickness adjustment variation of the non-end rack to obtain the thickness setting value total adjustment amount; the thickness setting value total adjustment amount is used to correct the outlet thickness setting value of the non-end rack;

[0056] A delayed transmission module is used to delay the output of the total adjustment amount of the thickness setting value of the non-end rack according to the rack speed of the non-end rack;

[0057] The rack speed correction amount calculation module is used to determine the rack speed correction amount of the non-end rack and the entrance tension roller according to the total adjustment amount of the thickness setting value output by the delay; the rack speed correction amount is used to correct the rack speed of the non-end rack and the entrance tension roller.

[0058] The present invention further provides a cold rolling mill with a function of dynamically adjusting the frame load, comprising the above-mentioned control module for dynamically adjusting the frame load of the cold rolling mill.

[0059] The beneficial effects of the present invention are: by comprehensively adjusting the outlet thickness of the frame based on the over-limit conditions of the frame's rolling force, load rate, and frame speed, and fully considering various factors of the frame's overload, the accurate judgment and timely adjustment of the frame's overload are achieved.

[0060] Furthermore, based on the characteristic that the strip moves sequentially in different frames during the rolling process, a delay time is set according to the moving speed of the strip, and the adjustment parameters of different frames are transmitted sequentially between the frames according to the delay time as the strip moves, thereby ensuring the coordinated adjustment of different frames.

[0061] The beneficial effects of the present invention are: by comprehensively adjusting the outlet thickness of the frame based on the over-limit conditions of the frame's rolling force, load rate, and frame speed, and fully considering various factors of the frame's overload, the accurate judgment and timely adjustment of the frame's overload are achieved.

[0062] Furthermore, based on the characteristic that the strip moves sequentially in different frames during the rolling process, a delay time is set according to the moving speed of the strip, and the adjustment parameters of different frames are transmitted sequentially between the frames according to the delay time as the strip moves, thereby ensuring the coordinated adjustment of different frames. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 2 is a schematic structural diagram of a five-stand cold rolling mill according to an embodiment of the present invention;

[0064] Figure 2 The present invention is a flowchart of a control method for dynamically adjusting the frame load of a cold rolling mill according to an embodiment of the present invention.

[0065] In the figure: 1-Frame No. 1, 2-Frame No. 2, 3-Frame No. 3, 4-Frame No. 4, 5-Frame No. 5, 6-Upper support roller, 7-Upper intermediate roller, 8-Upper working roller, 9-Lower working roller, 10-Lower intermediate roller, 11-Lower support roller, 12-Tension roller, 13-Coiler, 14-First variable frequency speed regulating motor, 15-Second variable frequency speed regulating motor, 16-Frequency converter, 17-Editable logic controller, 18-Pressing system. DETAILED DESCRIPTION

[0066] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0067] This embodiment provides a control method for dynamically adjusting the rack load of a cold rolling mill, comprising the following steps:

[0068] S1. When the preset dynamic load adjustment enabling conditions of the cold rolling mill are met, executing subsequent steps;

[0069] Specifically, the enabling conditions for dynamic load adjustment of the cold rolling mill are:

[0070] 1) The preset load rate of the secondary process control system of the cold rolling mill is within the range of 50% to 80%;

[0071] 2) The forward slip values ​​of all stands of the cold rolling mill are within the normal range (1.0~1.15);

[0072] 3) The actual current value of the transmission motor of one or more stands of the cold rolling mill exceeds 80% of the maximum current value;

[0073] 4) The actual current value of the transmission motor of all stands of the cold rolling mill exceeds 5% of the maximum current value;

[0074] 5) The unit is not in the dynamic specification change period;

[0075] 6) There is no belt break signal or emergency stop signal in the unit;

[0076] When all the above conditions are met, it is considered that the dynamic load adjustment of the cold rolling mill is enabled; when any of the above conditions is not met, the dynamic load adjustment amount is set to zero and it is enabled again after all the conditions are met;

[0077] S2. When the rolling force over-limit value of any non-head-end stand is greater than zero, the first thickness adjustment variation of each stand preceding the stand is accumulated according to the rolling force over-limit value of the stand; the rolling force over-limit value is the value at which the rolling force of a stand exceeds the maximum rolling force set for the stand;

[0078] See also Figure 1 In this embodiment, a five-stand cold rolling mill is taken as an example. The rolling direction is from left to right, and the stands are numbered 1 to 5 from left to right, namely stand 1, stand 2, stand 3, stand 4, and stand 5. Since the mechanical equipment of each stand is the same, stand 3 in the figure is taken as an example to illustrate the specific structure of the stand. Stand 3 includes an upper support roll 6, an upper intermediate roll 7, an upper working roll 8, a lower working roll 9, a lower intermediate roll 10, and a lower support roll 11, which are arranged in sequence from top to bottom. The strip is located between the upper working roll 8 and the lower working roll 9. The upper intermediate roll 7 and the lower intermediate roll 10 are respectively speed-regulated by a first variable frequency speed regulating motor 14 and a second variable frequency speed regulating motor 15. A tension roll 12 is provided at the entrance of the cold rolling mill, and a coiler 13 is provided at the exit.

[0079] The working mode of the cold rolling mill is as follows: the intermediate rollers are used for transmission, and the upper and lower intermediate rollers are speed-controlled by variable frequency speed-regulating motors, which are driven by a frequency converter 16. The programmable logic controller 17 (PLC) sends the speed adjustment value to the frequency converter 16, and the frequency converter 16 controls and adjusts the speed of the variable frequency speed-regulating motor according to the speed adjustment value so that the linear speed of the transmission roller reaches the set value; the cold rolling mill uses a screw-down system 18 to control the roll gap; the thickness control system (AGC) of the cold rolling mill is completed by adjusting the roll gap of the rolling mill and the transmission speed of each frame (it should be noted that in this embodiment, the frame load is limited only by adjusting the frame speed, and does not involve the control of the screw-down system); all control functions are programmed and implemented in the PLC. The PLC adopts a multi-CPU architecture, and each CPU can independently perform specific functions. For example, the AGC control and speed control involved in the present invention are all completed by different CPUs.

[0080] When the rolling force over-limit value of stand 5 is greater than 0, it is necessary to accumulate the first thickness adjustment changes of stands 1 to 4. Accordingly, the accumulated first thickness adjustment changes of stands 1 to 4 are expressed as:

[0081]

[0082] When the rolling force over-limit value of stand 4 is greater than 0, it is necessary to accumulate the first thickness adjustment changes of stands 1 to 3. Accordingly, the accumulated first thickness adjustment changes of stands 1 to 3 are expressed as:

[0083]

[0084] When the rolling force over-limit value of stand 3 is greater than 0, it is necessary to accumulate the first thickness adjustment changes of stands 1 and 2. Accordingly, the accumulated first thickness adjustment changes of stands 1 and 2 are expressed as:

[0085]

[0086] When the rolling force over-limit value of the No. 2 stand is greater than 0, the first thickness adjustment variation of the No. 1 stand needs to be accumulated. Accordingly, the accumulated first thickness adjustment variation of the No. 1 stand is expressed as:

[0087]

[0088] In the above formula, for Rolling force of stand No. for The maximum rolling force of the stand, That is, the rolling force of the No. 5 stand exceeds the limit value. for Conversion factor of rolling force of stand No. to outlet thickness, Preset for secondary process control system The outlet thickness setting value of the rack, where x1 ranges from 1 to 4;

[0089] For the No. 1 stand, in response to the rolling force exceeding limit of the subsequent No. 2 to No. 5 stands, the total first thickness adjustment change is expressed as: ;

[0090] For the No. 2 stand, in response to the rolling force exceeding the limit of the subsequent No. 3 to No. 5 stands, the total first thickness adjustment change is expressed as: ;

[0091] For the No. 3 stand, in response to the rolling force exceeding the limit of the subsequent No. 4-5 stands, the total first thickness adjustment change is expressed as: ;

[0092] For the No. 4 stand, in response to the rolling force exceeding limit of the subsequent No. 5 stand, the total first thickness adjustment variation is expressed as: ;

[0093] Thus:

[0094]

[0095]

[0096]

[0097]

[0098] for situation, Take 0;

[0099] In other embodiments of the present invention, for cold rolling mills with different numbers of stands, the method for accumulating the first thickness adjustment variation may refer to the above method, which will not be described in detail in this embodiment.

[0100] In this embodiment, the rolling force to outlet thickness conversion factor of each stand is different. The rolling force to outlet thickness conversion factor of the front stand is smaller, and the rolling force to outlet thickness conversion factor of the rear stand is larger. The rolling force to outlet thickness conversion factor is calculated by the secondary process control system of the cold rolling mill.

[0101] Since the outlet thickness of the end rack is the finished product thickness and cannot be changed, only the outlet thickness setting value and rack speed of the non-end rack can be modified;

[0102] S3. When the load rate over-limit value of any rack among the non-head-end racks is greater than zero, determining the second thickness adjustment change amount of the rack preceding the rack based on the load rate over-limit value of the rack; the load rate over-limit value is the value at which the load rate of a rack exceeds the maximum load rate set for the rack;

[0103] For a rack whose load rate over-limit value is not greater than zero, there is no need to adjust the outlet thickness setting value of the rack before the rack, so the second thickness adjustment change of the rack before the rack is the default zero;

[0104] Specifically, the calculation process of the second thickness adjustment variation is as follows:

[0105]

[0106] In the above formula, The second thickness adjustment variation for the x1 rack, The maximum load factor set for rack x1, is the load rate of rack x1 (in this embodiment, it is expressed as the percentage of the current value of the transmission motor passing through the rack to the maximum current of the transmission motor), That is the opposite of the load rate exceeding the limit value. is the conversion factor of the load rate of rack x1 to the outlet thickness; where x1 ranges from 1 to 4;

[0107] In the cold rolling mill, the conversion factor of the load rate to the outlet thickness of each stand is different. For the five-stand cold rolling mill in this embodiment, the conversion factor of the load rate to the outlet thickness of stand 2 is the largest. As the reduction of subsequent stands gradually decreases, the corresponding conversion factors of the load rate to the outlet thickness gradually decrease. In this embodiment, The value of is 0.1~0.35;

[0108] S4, summing the first thickness adjustment variation and the second thickness adjustment variation of the non-end rack and integrating the sum with respect to time to obtain a third thickness adjustment variation of the non-end rack;

[0109]

[0110] In the above formula, Indicates the third thickness adjustment change of rack x1 at the current moment, They represent the first thickness adjustment change and the second thickness adjustment change of rack x1 at a certain moment in the past. is the PLC sampling time, is the integration time parameter; in this embodiment, , .

[0111] S5. Obtaining a fourth thickness adjustment variation of the non-end rack by linear interpolation according to the rack speed of the non-end rack and a pre-stored numerical table;

[0112] Specifically, the relationship between the rack speed and the fourth thickness adjustment variation is nonlinear. Therefore, in this embodiment, 10 rack speed and fourth thickness adjustment variation data points are used to represent the relationship between the two. These 10 data points are pre-stored in the secondary process control system. During table lookup, the secondary process control system sends the data points to the PLC control system of the primary process control system. The PLC control system then performs linear interpolation processing based on the read rack speed and the stored data points to obtain the fourth thickness adjustment variation, which is expressed as:

[0113]

[0114] In the above formula, The fourth thickness adjustment variation for the x1 rack is: Indicates 10-point linear interpolation processing, is the rack speed of rack x1;

[0115] S6. Add the third thickness adjustment variation and the fourth thickness adjustment variation of the non-end frame to obtain a total thickness setting value adjustment;

[0116]

[0117] In the above formula, is the total adjustment amount of the thickness setting value, is the outlet thickness correction value of rack x1, The outlet thickness setting value of rack x1 preset in the secondary process control system;

[0118] S7, according to the rack speed of the non-end rack, delay outputting the total adjustment amount of the thickness setting value of the non-end rack;

[0119] Since the outlet thickness of each stand is mainly adjusted by adjusting the stand speed in the cold rolling mill, there is a time synchronization problem when adjusting the stand speeds. The correct adjustment sequence should be to adjust the stands in sequence. For example, if a certain section of strip steel just enters a certain stand, the speed of the stand starts to be adjusted, while the speed of the following stands has not started to be adjusted at this time. The speed of the next stand should not be adjusted until the section of strip steel enters the next stand.

[0120] In this embodiment, to address the timing issue of speed correction, multiple shift registers are used to delay the output of the total adjustment value of the thickness setting value of each stand. For stands 1 to 4 (i.e., non-end stands) of the five-stand cold rolling mill, four shift registers, namely shift registers 1 to 4, are set up. Taking stand 1 as an example, the function of shift register 1 (SR1) is to store the total adjustment value of the thickness setting value of stand 1 (or the exit thickness correction value) in the register, transmit it at the actual exit speed of stand 1, and wait until the sampling moment when the transmission distance is exactly greater than or equal to the distance between the roll gaps of stands 1 and 2. At this time, the total adjustment value of the thickness setting value stored in shift register 1 is transferred to shift register 2, thus simulating the transmission process of the strip between stands 1 and 2. Similarly, shift registers 2, 3, and 4 (SR2, SR3, and SR4) are used to delay the output of the exit thickness compensation value of stands 2, 3, and 4, respectively.

[0121] S8. Determine a frame speed correction amount for the non-end frame and the entrance tension roller based on the total adjustment amount of the thickness setting value outputted by the delay; the frame speed correction amount is used to correct the frame speed of the non-end frame and the entrance tension roller;

[0122] Since the rack speed of the cold rolling mill is set according to a certain speed ratio, when the speed of the rear rack needs to be adjusted, the rack speeds of all the preceding racks also need to be adjusted accordingly. Therefore, when calculating the rack speed correction of each rack, it is necessary to calculate from the rear rack to the front.

[0123] It should be understood that, in this embodiment, the total adjustment amount from the first to the thickness setting value of a certain rack is expressed as a percentage relative to the outlet thickness setting value of the rack;

[0124] In the five-stand cold rolling mill of this embodiment, at a certain moment, starting from stand 4 and counting upstream to the entrance tension roller (equivalent to stand 0 with no reduction), the stand speed correction value of each stand and the entrance tension roller is calculated as follows:

[0125]

[0126]

[0127]

[0128]

[0129]

[0130] In the above formula, Indicates the frame speed (i.e. line speed) correction value of the entrance tension roller. 、 、 、 They are the rack speed correction values ​​for racks 1 to 4 respectively. 、 、 、 Respectively represent the shift registers of racks 1 to 4, and here it represents the total adjustment amount of the thickness setting value output after a certain delay time (i.e. the value in brackets); in this embodiment It is expressed as a percentage of the rack speed setting value of rack No. x2, which is set in the secondary process control system, where x2 is 0~4.

[0131] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A control method for dynamically adjusting the rack load of a cold rolling mill, characterized in that: The following steps are involved: S1. When the preset dynamic load adjustment enabling conditions of the cold rolling mill are met, executing subsequent steps; S2. When the rolling force over-limit value of any non-head-end stand is greater than zero, the first thickness adjustment variation of each stand preceding the stand is accumulated according to the rolling force over-limit value of the stand; The rolling force over-limit value is the value at which the rolling force of a certain stand exceeds the maximum rolling force set for the stand; S3. When the load rate over-limit value of any rack among the non-head-end racks is greater than zero, determining the second thickness adjustment variation of the rack preceding the rack according to the load rate over-limit value of the rack; The load rate exceeding limit value is the value at which the load rate of a rack exceeds the maximum load rate set for the rack; S4, summing the first thickness adjustment variation and the second thickness adjustment variation of the non-end rack and integrating the sum with respect to time to obtain a third thickness adjustment variation of the non-end rack; S5. Obtaining a fourth thickness adjustment variation of the non-end rack by linear interpolation according to the rack speed of the non-end rack and a pre-stored numerical table; S6. Add the third thickness adjustment variation and the fourth thickness adjustment variation of the non-end frame to obtain a total thickness setting value adjustment; The total adjustment amount of the thickness setting value is used to correct the outlet thickness setting value of the non-end rack; S7, according to the rack speed of the non-end rack, delay outputting the total adjustment amount of the thickness setting value of the non-end rack; S8. Determine the frame speed correction amount of the non-end frame and the entrance tension roller according to the total adjustment amount of the thickness setting value output by the delay; The frame speed correction value is used to correct the frame speed of the non-end frame and the entrance tension roller.

2. The control method for dynamically adjusting the frame load of a cold rolling mill according to claim 1, characterized in that: The enabling conditions for the dynamic load regulation of the cold rolling mill are: 1) The preset load rate of the secondary process control system of the cold rolling mill is within the set range; 2) The forward slip values ​​of all stands of the cold rolling mill are within the set normal range; 3) The actual current value of the transmission motor of one or more stands of the cold rolling mill exceeds the first percentile of the maximum current value; 4) The actual current values ​​of the transmission motors of all stands of the cold rolling mill exceed the second percentile of the maximum current value; 5) The unit is not in the dynamic specification change period; 6) There is no belt break signal or emergency stop signal in the unit; When all the above conditions are met, it is considered that the dynamic load adjustment of the cold rolling mill is enabled.

3. The control method for dynamically adjusting the frame load of a cold rolling mill according to claim 1, characterized in that: Step S2 includes: S201, setting the default value of the first thickness adjustment variation of each rack to zero; S202, determining a rolling force over-limit value according to the rolling force of the non-head end stand and the maximum rolling force; S203. If there is a non-head-end stand with a rolling force over-limit value greater than zero, the first thickness adjustment changes of each stand before the stand are accumulated according to the rolling force over-limit value of the stand, the conversion factor of the rolling force of the stand to the outlet thickness, and the outlet thickness setting value of the stand before the stand.

4. The control method for dynamically adjusting the frame load of a cold rolling mill according to claim 1, characterized in that: S3 includes the following steps: S301, setting the default value of the second thickness adjustment variation of each rack to zero; S302: For a non-head-end rack having a load rate exceeding limit value greater than zero, determine a second thickness adjustment variation of a rack preceding the rack based on the load rate exceeding limit value of the rack and a conversion factor of the rack load rate to outlet thickness; S303 , determining a second thickness adjustment variation of each non-end rack according to steps S301 and S302 .

5. The control method for dynamically adjusting the frame load of a cold rolling mill according to claim 1, characterized in that: Step S4 includes the following steps: S401, summing a first thickness adjustment variation and a second thickness adjustment variation of a non-end rack at a certain moment to obtain a first thickness adjustment integrated quantity of the rack at that moment; S402, taking the ratio of the set sampling time and the set integration time parameter as a time coefficient; S403, multiplying the first thickness adjustment integrated quantity by the time coefficient to obtain the second thickness adjustment integrated quantity at that moment; S404, summing the second thickness adjustment integrated quantities at each previous moment to obtain the third thickness adjustment variation of the rack at the current moment; S405 , determining the fourth thickness adjustment variation of each non-end rack according to steps S401 to S404 .

6. The control method for dynamically adjusting the frame load of a cold rolling mill according to claim 1, characterized in that: Step S5 includes the following steps: S501, pre-store a number of rack speed-fourth thickness adjustment change data points as a table; S502: Read the rack speed of a non-end rack, and obtain the fourth thickness adjustment variation corresponding to the rack speed by linear interpolation based on the rack speed and a pre-stored data point of the rack speed-fourth thickness adjustment variation; S503 : Determine the fourth thickness adjustment variation of each non-end rack according to steps S501 and S502 .

7. The control method for dynamically adjusting the frame load of a cold rolling mill according to claim 1, characterized in that: Step S7 includes the following steps: S701. For any non-end rack, determine a delay time of the rack based on the rack speed of the rack and the distance between the rack and the rack immediately following the rack. S702: When the rack adjusts the outlet thickness of the rack according to the total adjustment amount of the thickness setting value, and the duration reaches the delay time, the total adjustment amount of the thickness setting value of the rack is output with a delayed time; S703 , according to step S701 to step S702 , outputting the total adjustment amount of the thickness setting value of each rack in the non-end rack with a delayed output.

8. The control method for dynamically adjusting the frame load of a cold rolling mill according to claim 1, characterized in that: Step S8 includes the following steps: S801. For any non-end rack, determine a rack speed correction value for the rack based on a total thickness setting value adjustment value of a rack immediately following the rack, a total thickness setting value adjustment value of a delayed output of the rack, and a rack speed correction value of the rack immediately following the rack. S802, determining a rack speed correction value for each rack in the non-end rack according to step S801; S803: Determine the frame speed correction amount of the entrance tension roller according to the frame speed correction amount of the head end frame and the total adjustment amount of the thickness setting value.

9. A control module for dynamically adjusting the rack load of a cold rolling mill, characterized in that: include: The dynamic load regulation enabling judgment module is used to activate the subsequent modules to execute corresponding steps when the preset dynamic load regulation enabling conditions of the cold rolling mill are met; A first thickness adjustment variation calculation module is configured to accumulate first thickness adjustment variations of each stand preceding the stand according to the rolling force excess value of the stand when the rolling force excess value of any stand other than the head end stand is greater than zero; The rolling force over-limit value is the value at which the rolling force of a certain stand exceeds the maximum rolling force set for the stand; a second thickness adjustment variation calculation module, configured to determine, when the load rate over-limit value of any non-head-end rack is greater than zero, the second thickness adjustment variation of the rack preceding the rack according to the load rate over-limit value of the rack; The load rate exceeding limit value is the value at which the load rate of a rack exceeds the maximum load rate set for the rack; a third thickness adjustment variation calculation module, configured to sum the first thickness adjustment variation and the second thickness adjustment variation of the non-end rack and then integrate the sum over time to obtain a third thickness adjustment variation of the non-end rack; a fourth thickness adjustment variation calculation module, configured to obtain a fourth thickness adjustment variation of the non-end rack by linear interpolation based on the rack speed of the non-end rack and a pre-stored numerical table; a thickness setting value total adjustment amount calculation module, configured to add the third thickness adjustment variation and the fourth thickness adjustment variation of the non-end frame to obtain the thickness setting value total adjustment amount; The total adjustment amount of the thickness setting value is used to correct the outlet thickness setting value of the non-end rack; A delayed transmission module is used to delay the output of the total adjustment amount of the thickness setting value of the non-end rack according to the rack speed of the non-end rack; The frame speed correction calculation module is used to determine the frame speed correction of the non-end frame and the entrance tension roller according to the total adjustment amount of the thickness setting value output by the delay; The frame speed correction value is used to correct the frame speed of the non-end frame and the entrance tension roller.

10. A cold rolling mill with a function of dynamically adjusting the rack load, characterized in that: It includes the control module for dynamically adjusting the frame load of the cold rolling mill as described in claim 9.

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