A time delay detection method for rolling reduction control system

Abstract

The present invention discloses a time delay detection method for a rolling reduction control system, comprising the following steps: S1, collecting frequency characteristics of the rolling reduction control system; S2, planning a thickness curve and establishing a roll gap reduction curve based on the thickness curve; S3, fine-machining the plate according to the thickness curve and making conversion marks; S4, actually rolling the plate after step S3 according to the roll gap reduction curve; S5, during the rolling process, the base system automatically records the measured rolling force and occurrence time; S6, characterizing and quantifying the time delay. The present invention uses a plate with a specific processing thickness curve, and the reduction system uses the same curve as the reduction input roll gap curve. The time delay of the reduction system is characterized by testing the time point of the rolling force mutation.

Description

Technical Field

[0001] The present invention relates to a method for detecting the accuracy of a rolling mill control system, and more specifically, to a method for detecting the time delay of a rolling reduction control system. Background Art

[0002] In modern basic automation control systems, due to the characteristics and interactions of control elements, the execution process after a signal is issued will have certain frequency errors, one of which is delay. Delay refers to the time required for an instruction or data packet to be transmitted from one end of a system to the other. It includes transmission delay, propagation delay, processing delay, and queuing delay, that is, system delay = transmission delay + propagation delay + processing delay + queuing delay, and the rationality of network status and signal processing are the main factors causing delay fluctuations. The rolling press control system is a complex basic control system with very high precision requirements for the action process. It is hoped that the delay is as small as possible to reduce precision deviation. The rolling press control system is highly complex and requires multiple data items to be calculated before output. The action process involved is also very complex, and each signal transmission and processing process will incur a delay.

[0003] Numerous technologies and patents exist for detecting time delay characteristics. For example, a common approach is to simulate and determine time delay by continuously varying curvature settings. This method is simple to implement but can result in significant errors. Many institutions also employ more accurate methods closer to actual measurements, primarily comparing operational results with operational settings to determine time delay. However, actual measurement methods and approaches vary widely, making implementation difficult. Due to the significant diversity of industries involved in basic control systems, there is currently no superior method for time delay detection in rolling reduction control systems.

[0004] In recent years, as the demand for basic automation precision continues to increase, the requirements for system latency performance have also become increasingly stringent. Latency is an implicit indicator, and many systems lack detection methods, making it difficult to characterize latency. Summary of the Invention

[0005] In view of the above-mentioned defects in the prior art, the purpose of the present invention is to provide a time delay detection method for a rolling reduction control system. By using a plate with a specific processing thickness curve, the reduction system uses the same curve as the reduction input roll gap curve, and characterizes the time delay of the reduction system by testing the time point of the rolling force mutation.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A time delay detection method for a rolling reduction control system comprises the following steps:

[0008] S1. Collect the frequency characteristics of the rolling reduction control system;

[0009] S2. Plan the thickness curve and establish the roll gap reduction curve based on the thickness curve;

[0010] S3. The plate is finely processed according to the thickness curve and the conversion mark is made;

[0011] S4, performing actual rolling on the plate obtained in step S3 according to the roll gap reduction curve;

[0012] S5. During the rolling process, the base system automatically records the measured rolling force and occurrence time;

[0013] S6. Characterize and eigenvalue the time delay.

[0014] Preferably, in step S1, the lowest frequency is used as the frequency of the rolling reduction control system.

[0015] Preferably, in step S2, the thickness curve is constructed according to the frequency of the rolling reduction control system, and one curve cycle is composed of 8 rolling reduction control system cycles, and the 8 rolling reduction control system cycles are respectively roll gap maintaining section-roll gap reduction section-roll gap maintaining section-roll gap reduction section-roll gap maintaining section-roll gap lifting section-roll gap maintaining section-roll gap lifting section, and then enter the second cycle;

[0016] The roll gap reduction curve is a thickness curve, and the thickness is set by reverse calculation based on the rolling force and the rolling mill stiffness.

[0017] Preferably, the roller gap pressing section and the roller gap lifting section are symmetrical curves.

[0018] Preferably, the roll gap pressure curve S is set by back-calculation using a spring equation, i.e., S = (Ht-R0) + Fr0 / G;

[0019] Where Ht is the thickness curve, R0 is the rolling reduction, Fr0 is the rolling force calculated based on the rolling reduction R0, is the specific value of Fr0, and G is the rolling mill stiffness.

[0020] Preferably, in step S3, the plate is made of a material having uniform quality.

[0021] Preferably, in step S4, the rolling speed V0 is set, and the rolling process is a uniform speed process.

[0022] Preferably, in step S5, the base system completes recording the process from the start of rolling to the end of rolling.

[0023] Preferably, in step S6, the rolling force data is sorted, and based on the rolling force mark, the data trend inflection point is found in the data curve, and whether to take a value is determined according to the data difference and the distance from the rolling force mark.

[0024] Preferably, the value-taking logic is:

[0025] The rolling force stable section is a stable rolling force section of 3 measurement cycles or more. The starting time point of the stable section is defined as the inflection point, which is considered to be the starting point or end point of the execution cycle of the rolling reduction control system.

[0026] The inflection point is at least one measurement cycle away from the marking point;

[0027] The inflection point is between two adjacent rolling force marking points;

[0028] The time difference between adjacent effective inflection points is the cycle time T1_n of the rolling reduction control system;

[0029] The difference between the execution period and the set period is the system delay, and the average delay is taken as the system delay.

[0030] The present invention provides a time delay detection method for a rolling reduction control system. This method is used to measure the time delay by recording the rolling force over time when rolling a material with a specific thickness curve using a specific roll gap curve. The method is simple to implement and does not require complex detection equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 1 is a flow chart of the time delay detection method of the present invention;

[0032] Figure 2 1 is a flow chart of step S1 in the time delay detection method of the present invention;

[0033] Figure 3 Schematic diagram of the thickness curve in step S2 of the time delay detection method of the present invention;

[0034] Figure 4 Schematic diagram of the roller gap curve in step S2 of the time delay detection method of the present invention;

[0035] Figure 5 Schematic diagram of rolling force peaks and troughs in step S2 of the time delay detection method of the present invention;

[0036] Figure 6 Schematic diagram of the material shape in step S3 of the time delay detection method of the present invention;

[0037] Figure 7 1 is a schematic diagram of the measured records of the base system in step S5 of the time delay detection method of the present invention;

[0038] Figure 8 Schematic diagram of the rolling force causing the time delay in step S5 of the time delay detection method of the present invention;

[0039] Figure 92 is a schematic diagram of a rolling force curve obtained by measuring the rolling force in an embodiment of the time delay detection method of the present invention;

[0040] Figure 10 Schematic diagram of determining a cycle inflection point in an embodiment of the time delay detection method of the present invention. DETAILED DESCRIPTION

[0041] In order to better understand the above technical solutions of the present invention, the technical solutions of the present invention are further described below with reference to the accompanying drawings and embodiments.

[0042] Combine Figure 1 As shown, the present invention provides a time delay detection method for a rolling reduction control system. The method can characterize the time delay of the reduction system by detecting the time point of the rolling force mutation using a plate having a specific processing thickness curve and the same curve as the reduction input roll gap curve. The processing frequency of the rolling force detection system is much higher than the reduction system frequency. The method specifically includes the following steps:

[0043] S1. Collect the frequency characteristics of the rolling reduction control system;

[0044] S2. Plan the thickness curve and establish the roll gap reduction curve based on the thickness curve;

[0045] S3. The plate is finely processed according to the thickness curve and the conversion mark is made;

[0046] S4, performing actual rolling on the plate obtained in step S3 according to the roll gap reduction curve;

[0047] S5. During the rolling process, the base system automatically records the measured rolling force and occurrence time;

[0048] S6. Characterize and eigenvalue the time delay.

[0049] In the above step S1, normally the rolling reduction control system requires multi-node processing and multiple transmissions. The calculation cycles and frequencies of the multiple nodes are different. Therefore, in order to transmit the temperature of the system, the rolling reduction control system often uses the lowest frequency as the frequency of its system. If the system performance is poor, the cycle will be reduced to 2 times of the lowest frequency, that is, the cycle T0 of the system setting signal. Figure 2 As shown, the actual rolling force measurement period is T1. Normally, T1 is much smaller than T0.

[0050] In step S2, the thickness curve Ht is constructed based on the frequency of the rolling reduction control system. Each curve cycle consists of eight rolling reduction control system cycles, with the following sequence: roll gap maintenance segment - roll gap reduction segment - roll gap maintenance segment - roll gap reduction segment - roll gap maintenance segment - roll gap lift segment - roll gap maintenance segment - roll gap lift segment. The second cycle then proceeds, with the roll gap reduction segment and roll gap lift segment forming symmetrical curves. The required distance L0 for each cycle is determined based on the specific rolling speed V0 and reduction rate R0: L0 = T0 * V0 / (1 + R0), where R0 is a fixed value within this curve and ranges from 5% to 10%. The test thickness curve is divided into a uniform thickness segment and a variable thickness segment (with a unit cycle thickening value of Δh), corresponding to the processes of a constant roll gap and roll gap reduction or lift, respectively. The thickness difference in the variable thickness segment is less than the limit value within a single cycle of the rolling reduction system's roll gap lift or reduction, with the thickness curve limit difference ranging from 0.1 mm to 10 mm. A high point Hp of rolling force is established at the end of each period length, where the high point of the continuous roll gap section is Hp0, and the high point of the roll gap change period is Hp1. Hp0 and Hp1 are determined by the rolling force measurement period Tm, and their length L-Hp satisfies at least one Tm period, that is, L-Hp=Tm*V0; its height is related to the roll gap change amount H-Hp=(Δh / T0)*T1, and Hp is not included in the rolled piece thickness Ht. These high points will cause the rolling force to increase during the rolling process, so the recorded rolling force protrusion point is the dividing point between the periods. Its periodic thickness curve can be seen Figure 3 As shown, the thickness curve is a periodic curve, and the continuation of the subsequent curve is determined by the length of the rolled piece. In addition, the actual limit difference of the thickness curve is between 0.1mm and 10mm, which is not as large as the thickness difference shown in the curve, and will not affect the roller transportation of the rolled piece.

[0051] The roll gap reduction curve S is the thickness of the thickness curve Ht, which is calculated and set based on the rolling force and the mill stiffness G. The required rolling force Fr0 is determined by the reduction rate R0, the rolling width B0, and the material properties of the rolled product. When the material properties of the rolled product are determined, the calculated value of Fr0 should be within the linear stiffness range of the rolling mill, that is, Fr0 should be greater than the mill's calibrated rolling force of 1.1*Frb. To ensure the accuracy of the rolling force marking point of the rolled product, Fr0 should be less than 2*Frb. The mill stiffness G is determined by the mechanical structure of the rolling mill itself. Above a certain rolling force, it has a linear relationship with the rolling force, that is, Fr0 = σ*Ac*Ka, where σ is a function related to the deformation resistance and is related to the reduction rate R0 and material properties; Ac is a function related to the deformation contact area and is related to the roll diameter reduction rate R0, the rolled product thickness H, and the steel plate width B0; Ka is the rolling force accuracy adjustment coefficient and is related to the rolling mill characteristics. The roll gap reduction curve S is set by back calculation using the spring equation, i.e. S = (Ht-R0) + Fr0 / G, where Ht is the thickness curve, R0 is the rolling reduction, Fr0 is the rolling force calculated based on the rolling reduction R0, G is the concrete value of Fr0, and G is the rolling mill stiffness. The rolling roll gap curve does not consider the workpiece convex point Hp. The roll gap reduction curve S is as follows: Figure 3 As shown, the solid line is the set roll gap curve, and the dotted line is the actual roll gap curve with execution deviation due to time delay. Only one cycle of the roll gap curve is listed, and its cycle will match the thickness cycle of the rolled piece.

[0052] Measurement principle: The roll gap reduction curve S will not match the thickness curve Ht due to the time delay of the rolling reduction control system during the rolling process. The actual roll gap will be delayed near the mark point, and the actual reduction amount will begin to fluctuate, resulting in a large fluctuation in the actual rolling force Fr (the original design Fr0 can be defaulted to a constant value due to the constant reduction rate R0). Since the thickness curve fluctuates significantly, peaks and troughs of the rolling force will appear when the actual roll gap is executed, such as Figure 5 As shown in FIG, the time between the peak and the trough is the actual cycle time of the rolling reduction system, and the difference from the system setting time is its time delay.

[0053] In the above step S3, the plate is made of a uniform material such as pure copper or pure lead, and is processed uniformly according to the thickness curve Ht. The shape of the processed material is as follows: Figure 6 shown.

[0054] In the above step S4, the rolling speed V0 is set first, and the rolling process is a uniform speed process. The roll bite is used as the starting point, and the roll gap curve is input until the rolling of the workpiece is completed.

[0055] In the above step S5, the rolling mill is equipped with a pressure sensor system, and the base system records the rolling force Fr and time in real time, which can complete the recording process from the start of rolling to the end of rolling. The cycle of the rolling force recording process is much shorter than the cycle of the rolling system. Generally speaking, the cycle of the rolling pressure system is about 8ms to 32ms, and the cycle of the rolling force recording can be achieved in 1ms to 4ms. The base system records in real time such as Figure 7 As shown in the figure, the time interval between each recording point between the two vertical dotted lines A is the detection period.

[0056] Due to the occurrence of time delay, the measured rolling force Fr will fluctuate greatly, as shown in the curve. Figure 8 shown.

[0057] In the above step S6, the rolling force data is sorted, and based on the rolling force mark, the data trend inflection point is found in the data curve, and the value is determined based on the data difference and the distance from the rolling force mark. The value logic is:

[0058] The rolling force stable segment is a stable rolling force segment of three measurement cycles or more. The starting time of the stable segment is defined as the inflection point, which is considered to be the starting point or end point of the execution cycle of the rolling pressure control system; the inflection point is at least one measurement cycle away from the mark point; the inflection point is between two adjacent rolling force mark points; the time difference between adjacent effective inflection points is the cycle time T1_n of the rolling pressure control system; the difference between the execution cycle and the set cycle (i.e., T1_n-T0) is the system delay, and the average value of the delay is taken as the system delay.

[0059] Example

[0060] Rolling mill: Roller diameter 120mm, roll length 300mm;

[0061] Control element: S7400;

[0062] Rolling mill pressing system cycle: 32ms;

[0063] Rolling force measurement frequency: 1ms, recording time frequency: 0.1ms;

[0064] Roll gap depression and lift curve design: single cycle roll gap movement 480μm;

[0065] The rolled piece thickness curve has about 6 cycles;

[0066] Rolled product: Material is copper T1, single piece size: 100mm×200mm×3000mm;

[0067] Rolling speed V0: 2m / s;

[0068] Reduction rate R0: 6%;

[0069] Roll gap speed: 15mm / s.

[0070]

[0071]

[0072]

[0073] The rolling force curve is measured as follows: Figure 9 As shown, the inflection point position (the end point of this cycle and the start point of the next cycle) is determined by logic, such as Figure 10 The circled point in the figure is the inflection point, and the execution cycle time of the compression system, T1_1 to T1_20, is determined. Compared with the compression cycle of 32ms, the average value results in a system latency of 0.945ms.

[0074]

[0075] Those skilled in the art should recognize that the above embodiments are merely intended to illustrate the present invention and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A time delay detection method for a rolling reduction control system, characterized in that: The following steps are involved: S1. Collect the frequency characteristics of the rolling reduction control system; S2. Plan the thickness curve and establish the roll gap reduction curve based on the thickness curve. In step S2, the thickness curve is constructed according to the frequency of the rolling reduction control system. One curve cycle is composed of eight rolling reduction control system cycles. The eight rolling reduction control system cycles are respectively roll gap maintaining section-roll gap reduction section-roll gap maintaining section-roll gap reduction section-roll gap maintaining section-roll gap lifting section-roll gap maintaining section-roll gap lifting section, and then enter the second cycle; The thickness of the roll gap reduction curve is set by reverse calculation based on the rolling force and the rolling mill stiffness. The roll gap pressure curve S is set by back calculation of the spring equation, that is, S = (Ht-HtR0) + Fr0 / G; Where Ht is the thickness curve, mm, R0 is the reduction, mm, Fr0 is the required rolling force, N, G is the rolling mill stiffness, N / mm; S3. The plate is finely processed according to the thickness curve and the conversion mark is made; S4, performing actual rolling on the plate obtained in step S3 according to the roll gap reduction curve; S5. During the rolling process, the base system automatically records the measured rolling force and occurrence time; S6. Characterize and eigenvalue the time delay. In step S6, the rolling force data is sorted out, and based on the rolling force mark, the data trend inflection point is found in the data curve, and the value is determined according to the data difference and the distance from the rolling force mark. The value logic is: The rolling force stable section is a stable rolling force section of 3 measurement cycles or more. The starting time point of the stable section is defined as the inflection point, which is considered to be the starting point or end point of the execution cycle of the rolling reduction control system. The inflection point is at least one measurement cycle away from the marking point; The inflection point is between two adjacent rolling force marking points; The time difference between adjacent effective inflection points is the cycle time T1_n of the rolling reduction control system; The difference between the execution period and the set period is the system delay, and the average delay is taken as the system delay.

2. The time delay detection method of the rolling reduction control system according to claim 1, characterized in that: In the step S1, the lowest frequency is used as the frequency of the rolling reduction control system.

3. The time delay detection method of the rolling reduction control system according to claim 1, characterized in that: The roller gap pressing section and the roller gap lifting section are symmetrical curves.

4. The time delay detection method of the rolling reduction control system according to claim 1, characterized in that: In step S3, the plate is made of a material having uniform quality.

5. The time delay detection method of the rolling reduction control system according to claim 1, characterized in that: In step S4, the rolling speed V0 is set, and the rolling process is a uniform speed process.

6. The time delay detection method of the rolling reduction control system according to claim 1, characterized in that: In step S5, the base system completes recording the process from the start of rolling to the end of rolling.

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