Feedforward Compensation Method and System for Entrance Tension in Feedforward Thickness Control of Cold Rolling Mill

Abstract

The present invention provides a feedforward compensation method for the inlet tension in the feedforward thickness control of a single-stand cold rolling mill, including: delaying and tracking the strip inlet thickness deviation measured by the thickness gauge at the inlet of the stand to the roll gap of the rolling mill, and calculating the feedforward AGC roll gap adjustment amount; filtering the feedforward AGC roll gap adjustment amount; calculating the actual roll force based on the filtered roll gap adjustment amount; calculating the inlet strip speed compensation based on the roll force; calculating the inlet linear acceleration compensation based on the inlet linear speed compensation; calculating the inlet coiling torque compensation based on the inlet linear acceleration compensation, and realizing the compensation for the inlet tension through the adjustment of the coiling motor torque. The feedforward AGC can effectively suppress the influence of the strip inlet thickness deviation at the inlet of the stand on the strip thickness at the outlet of the stand and quickly eliminate the short-term thickness deviation. The adjustment of the feedforward AGC roll gap position will cause fluctuations in the strip inlet tension at the inlet of the stand. Therefore, it is necessary to perform feedforward compensation for the inlet tension of the stand while adjusting the roll gap position to eliminate the inlet tension fluctuations.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgical automation, and particularly relates to a feedforward compensation method and system for the inlet tension of the feedforward thickness control of a single-stand cold rolling mill. Background Art

[0002] The automatic gauge control system of a single-stand cold rolling mill generally includes three control methods: feedforward AGC, mass flow AGC, and monitoring AGC. In the prior art, the Chinese patent with the publication number CN 108057720A discloses a feedforward compensation method and system for the inlet tension of the mass flow thickness control; the Chinese patent with the publication number CN 107913911A discloses a feedforward compensation method and system for the inlet tension of the monitoring thickness control. The two thickness control methods of mass flow AGC and monitoring AGC belong to feedback control to eliminate the influence of strip speed, tension, and friction coefficient changes on the strip thickness at the outlet of the stand. The adjustment of the roll gap position will cause fluctuations in the inlet tension. The above two patents in the prior art can eliminate the inlet tension fluctuations caused by the roll gap position adjustment of mass flow AGC and monitoring AGC. However, in the prior art, there is still a lack of a technical solution for the feedforward compensation method of the inlet tension by feedforward AGC. Summary of the Invention

[0003] In order to solve the technical problems raised in the background art, the present invention provides a feedforward compensation method and system for the inlet tension of the feedforward thickness control of a single-stand cold rolling mill. The feedforward AGC measures the thickness deviation of the strip at the inlet of the stand through a thickness gauge installed at the inlet of the stand, and the control system adjusts the roll gap position of the stand according to the inlet thickness deviation to accurately control the strip thickness at the outlet of the stand. The feedforward AGC can effectively suppress the influence of the strip thickness deviation at the inlet of the stand on the strip thickness at the outlet of the stand and quickly eliminate short-term thickness deviations. The adjustment of the roll gap position by the feedforward AGC will cause fluctuations in the strip tension at the inlet of the stand. Therefore, it is necessary to perform feedforward compensation on the inlet tension of the stand while adjusting the roll gap position to eliminate the inlet tension fluctuations.

[0004] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0005] A feedforward compensation method for the inlet tension of the feedforward thickness control of a single-stand cold rolling mill includes the following steps:

[0006] Step 1: Measure the strip inlet thickness deviation;

[0007] Step 2: Delay and track the measured strip inlet thickness deviation to the roll gap of the rolling mill, and calculate the feedforward AGC roll gap adjustment amount according to the thickness deviation;

[0008] Step 3: Filter the feedforward AGC roll gap adjustment amount;

[0009] Step 4: Calculate the actual roll force based on the filtered roll gap adjustment amount;

[0010] Step 5: Calculate the inlet strip speed compensation based on the roll force;

[0011] Step 6: Calculate the inlet line acceleration compensation based on the inlet line speed compensation;

[0012] Step 7: Calculate the inlet coiling torque compensation based on the inlet line acceleration compensation;

[0013] Step 8: Achieve the inlet tension compensation through the coiling motor torque adjustment.

[0014] Further, in the above-mentioned Step 1, measure the strip inlet thickness deviation by the thickness gauge at the inlet of the mill stand.

[0015] Further, in the above-mentioned Step 2, calculate the feedforward AGC roll gap adjustment amount according to the thickness deviation, specifically:

[0016]

[0017] In the formula: ΔS - Feedforward AGC roll gap adjustment amount (mm);

[0018] Δh - Mill stand inlet thickness deviation (mm);

[0019] M - Strip plasticity coefficient (t / mm);

[0020] K - Mill stand elasticity coefficient (t / mm).

[0021] Further, in the above-mentioned Step 3, perform a first-order low-pass filtering on the roll gap adjustment amount, and the transfer function is:

[0022]

[0023] In the formula: T a - Roll gap adjustment amount filtering time constant (s);

[0024] T a Is set as the time constant of the roll gap adjustment system.

[0025] Further, in the above-mentioned Step 4, calculate the actual roll force according to the filtered feedforward AGC roll gap adjustment amount:

[0026]

[0027] In the formula: Δh act - Feedforward AGC actual roll force;

[0028] ΔS' - Filtered roll gap adjustment amount;

[0029] M-strip plasticity coefficient (t / mm);

[0030] K-frame elastic coefficient (t / mm).

[0031] Furthermore, in step 5, the inlet strip speed compensation amount is calculated based on the principle of equal metal flow rate per second;

[0032] In the initial state, the metal flow rates at the rack inlet and outlet are equal:

[0033] v*h=v x *h x

[0034] When the inlet thickness changes, in order to keep the metal flow rate unchanged, the inlet linear speed needs to be compensated. The metal flow rate at the inlet and outlet of the rack is:

[0035] (v+Δv)*(h+Δh act )=v x *h x

[0036] Where: h x -Export thickness setting value (mm);

[0037] h-entrance thickness setting value (mm);

[0038] v x -Export line speed (m / s);

[0039] v-inlet linear velocity (m / s);

[0040] Δv-inlet linear velocity compensation (m / s);

[0041] Δh act -Actual amount of feedforward AGC depression;

[0042] Combine the two equations to calculate Δv:

[0043]

[0044] Combined with the actual pressure formula of the feedforward AGC in step 4, Δv is expressed as:

[0045]

[0046] Where: ΔS'-roller gap adjustment after filtering.

[0047] Furthermore, in step 6, the inlet linear velocity compensation is converted into the inlet linear acceleration compensation using a differential link:

[0048]

[0049] Where: acorr_FFC - Entrance line acceleration compensation (m / s 2 );

[0050] h - Set value of entrance thickness (mm);

[0051] v - Entrance line speed (m / s);

[0052] Δv - Entrance line speed compensation (m / s);

[0053] Δh act - Actual roll gap reduction of feedforward AGC;

[0054] ΔS' - Filtered roll gap adjustment;

[0055] M - Plastic coefficient of strip steel (t / mm);

[0056] K - Elastic coefficient of stand (t / mm).

[0057] Furthermore, in step 7, according to the entrance line acceleration compensation, calculate the torque compensation of the entrance coiler:

[0058]

[0059] In the formula: a corr_FFC - Entrance line acceleration compensation (m / s 2 );

[0060] J - Moment of inertia of the entrance coiler kg·m 2 ;

[0061] i - Transmission ratio of the entrance coiler;

[0062] r - Coil radius of the entrance coiler (m).

[0063] The present invention also provides a feedforward compensation system for the entrance tension of the feedforward thickness control of a single-stand cold rolling mill, including a detection device, a processor, and a coiler motor drive device;

[0064] The detection device is used to detect the strip steel entrance thickness deviation;

[0065] The processor receives the detection signal of the detection device, runs the foregoing method, calculates the entrance strip steel speed compensation, the entrance line speed compensation, calculates the entrance line acceleration compensation and the entrance coiling torque compensation;

[0066] The processor outputs speed and torque signals to the coiler motor drive device, and drives the coiler motor through the coiler motor drive device to perform torque adjustment to achieve compensation for the strip steel tension at the entrance of the stand.

[0067] The present invention further provides a processor of a computer. The processor receives the detection signal of a detection device, runs the foregoing method, calculates the inlet strip speed compensation, the inlet line speed compensation, the inlet line acceleration compensation, and the inlet coiling torque compensation, and compensates the strip tension at the inlet of the stand through torque adjustment of the coiling motor.

[0068] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0069] The feedforward compensation method and system for inlet tension in the feedforward thickness control of a single-stand cold rolling mill according to the present invention achieve the feedforward compensation of the inlet tension by the feedforward AGC roll gap adjustment, improve the control accuracy of the inlet tension, and eliminate the inlet tension fluctuation caused by the feedforward AGC roll gap adjustment. Description of the Drawings

[0070] Figure 1 is a flowchart of a feedforward compensation method for inlet tension in the feedforward thickness control of a single-stand cold rolling mill according to the present invention;

[0071] Figure 2 is a block diagram of a feedforward compensation system for inlet tension in the feedforward thickness control of a single-stand cold rolling mill according to the present invention. Detailed Embodiments

[0072] The following detailed description of the specific embodiments provided by the present invention is made in conjunction with the accompanying drawings.

[0073] The feedforward compensation method and system for inlet tension in the feedforward thickness control of a single-stand cold rolling mill according to the present invention are used for a single-stand cold rolling mill. A thickness gauge and a strip speed detection instrument are installed at the inlet and outlet of the stand, and the inlet and outlet coiling machines adopt a torque control mode.

[0074] Embodiment 1:

[0075] As Figure 1 shown, a feedforward compensation method for inlet tension in the feedforward thickness control of a single-stand cold rolling mill includes the following steps:

[0076] Step 1: Measure the strip inlet thickness deviation;

[0077] Step 2: Delay and track the measured strip inlet thickness deviation to the roll gap of the rolling mill, and calculate the feedforward AGC roll gap adjustment amount according to the thickness deviation;

[0078] Step 3: Filter the feedforward AGC roll gap adjustment amount;

[0079] Step 4: Calculate the actual roll reduction amount according to the filtered roll gap adjustment amount;

[0080] Step 5: Calculate the inlet strip speed compensation according to the roll reduction amount;

[0081] Step 6: Calculate the inlet line acceleration compensation based on the inlet line speed compensation;

[0082] Step 7: Calculate the inlet coiling torque compensation based on the inlet line acceleration compensation;

[0083] Step 8: Achieve the inlet tension compensation through the coiling motor torque regulation.

[0084] The specific implementation process is as follows:

[0085] In step 1 mentioned above, measure the strip inlet thickness deviation through the thickness gauge at the inlet of the frame.

[0086] In step 2 mentioned above, calculate the feedforward AGC roll gap adjustment amount based on the thickness deviation, specifically:

[0087]

[0088] In the formula: ΔS - Feedforward AGC roll gap adjustment amount (mm);

[0089] Δh - Frame inlet thickness deviation (mm);

[0090] M - Strip plasticity coefficient (t / mm);

[0091] K - Frame elasticity coefficient (t / mm).

[0092] In step 3 mentioned above, perform a first-order low-pass filter on the roll gap adjustment amount, and the transfer function is:

[0093]

[0094] In the formula: T a - Roll gap adjustment amount filtering time constant (s);

[0095] T a Is set as the time constant of the roll gap adjustment system.

[0096] In step 4 mentioned above, calculate the actual roll pressure based on the filtered feedforward AGC roll gap adjustment amount:

[0097]

[0098] In the formula: Δh act - Feedforward AGC actual roll pressure;

[0099] ΔS' - Filtered roll gap adjustment amount;

[0100] M - Strip plasticity coefficient (t / mm);

[0101] K - Frame elasticity coefficient (t / mm).

[0102] In the step 5, the inlet strip speed compensation amount is calculated according to the principle of equal metal flow rate per second;

[0103] In the initial state, the metal flow rates at the rack inlet and outlet are equal:

[0104] v*h=v x *h x

[0105] When the inlet thickness changes, in order to keep the metal flow rate unchanged, the inlet linear speed needs to be compensated. The metal flow rate at the inlet and outlet of the rack is:

[0106] (v+Δv)*(h+Δh act )=v x *h x

[0107] Where: h x -Export thickness setting value (mm);

[0108] h-entrance thickness setting value (mm);

[0109] v x -Export line speed (m / s);

[0110] v-inlet linear velocity (m / s);

[0111] Δv-inlet linear velocity compensation (m / s);

[0112] Δh act -Actual amount of feedforward AGC depression;

[0113] Combine the two equations to calculate Δv:

[0114]

[0115] Combined with the actual pressure formula of the feedforward AGC in step 4, Δv is expressed as:

[0116]

[0117] Where: ΔS'-roller gap adjustment after filtering.

[0118] In step 6, the inlet linear velocity compensation is converted into the inlet linear acceleration compensation using a differential link:

[0119]

[0120] Where: a corr_FFC -Entry line acceleration compensation (m / s 2 );

[0121] h-entrance thickness setting value (mm);

[0122] v - Inlet line speed (m / s);

[0123] Δv - Inlet line speed compensation (m / s);

[0124] Δh act - Actual roll gap reduction of the feedforward AGC;

[0125] ΔS' - Filtered roll gap adjustment;

[0126] M - Plastic coefficient of the strip (t / mm);

[0127] K - Elastic coefficient of the stand (t / mm).

[0128] In step 7, according to the inlet line acceleration compensation, calculate the torque compensation of the inlet coiler:

[0129]

[0130] Where: a corr_FFC - Inlet line acceleration compensation (m / s 2 );

[0131] J - Moment of inertia of the inlet coiler kg·m 2 ;

[0132] i - Transmission ratio of the inlet coiler;

[0133] r - Radius of the strip coil of the inlet coiler (m).

[0134] Example 2:

[0135] The present invention also provides a feedforward compensation system for the inlet tension in the feedforward thickness control of a single - stand cold rolling mill, including a detection device, a processor, and a coiler motor drive device.

[0136] The detection device is used to detect the thickness deviation of the strip at the inlet.

[0137] The processor receives the detection signal of the detection device, runs the aforementioned method, and calculates the inlet strip speed compensation, inlet line speed compensation, inlet line acceleration compensation, and inlet coiler torque compensation.

[0138] The processor outputs speed and torque signals to the coiler motor drive device, and drives the coiler motor through the coiler motor drive device to perform torque adjustment to achieve compensation for the strip tension at the inlet of the stand.

[0139] Example 3:

[0140] The present invention also provides a processor of a computer. The processor receives the detection signal of a detection device, runs the foregoing method, calculates the inlet strip speed compensation, the inlet line speed compensation, calculates the inlet line acceleration compensation and the inlet coiling torque compensation, and realizes the compensation of the strip tension at the inlet of the stand through torque adjustment of the coiling motor.

[0141] In summary, for the feedforward thickness control of the single-stand cold rolling mill of the present invention, the feedforward compensation method and system for the inlet tension realize the feedforward compensation of the inlet tension by the feedforward AGC roll gap adjustment, improve the control accuracy of the inlet tension, and eliminate the inlet tension fluctuation caused by the feedforward AGC roll gap adjustment.

[0142] The above embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation manners and specific operation processes are given. However, the protection scope of the present invention is not limited to the above embodiments. The methods used in the above embodiments are all conventional methods unless otherwise specified.

Claims

1. A feedforward compensation method for the inlet tension in the feedforward thickness control of a cold rolling mill, characterized in that, It includes the following steps: Step 1: Measure the strip inlet thickness deviation; Step 2: Delay and track the measured strip inlet thickness deviation to the rolling mill roll gap, and calculate the feedforward AGC roll gap adjustment amount according to the thickness deviation; Step 3: Filter the feedforward AGC roll gap adjustment amount; Step 4: Calculate the actual roll reduction according to the filtered roll gap adjustment amount; Step 5: Calculate the inlet strip speed compensation according to the roll reduction; Step 6: Calculate the inlet line acceleration compensation according to the inlet line speed compensation; Step 7: Calculate the inlet coiling torque compensation according to the inlet line acceleration compensation; Step 8: Achieve the inlet tension compensation through the coiling motor torque adjustment; In the said Step 5, calculate the inlet strip speed compensation amount according to the principle of equal metal second flow rate; In the initial state, the metal flow rates at the inlet and outlet of the stand: v * h = v x * h x When the inlet thickness changes, to keep the metal second flow rate unchanged, it is necessary to compensate the inlet line speed, and the metal flow rates at the inlet and outlet of the stand are equal: (v + Δv) * (h + Δh act ) = v x * h x where: h x - Set value of the outlet thickness (mm); h - Inlet thickness set value (mm); v x - Outlet linear velocity (m / s); v - Inlet line speed (m / s); Δv - Inlet line speed compensation amount (m / s); Δh act - Actual roll gap of the feedforward AGC; Simultaneously solve the two equations to calculate Δv: Simultaneously solve with the feedforward AGC actual roll reduction formula in Step 4, and Δv is expressed as: In the formula: ΔS' - Filtered roll gap adjustment amount; Δh act - Actual roll gap of the feedforward AGC; ΔS' - Filtered roll gap adjustment amount; M - Strip plasticity coefficient (t / mm); K - Stand elasticity coefficient (t / mm).

2. The feedforward compensation method for the inlet tension in the feedforward thickness control of a cold rolling mill according to claim 1, characterized in that, In the said Step 1, measure the strip inlet thickness deviation through the thickness gauge at the inlet of the stand.

3. A feedforward compensation method for the inlet tension in the feedforward thickness control of a cold rolling mill according to claim 1, characterized in that In the said Step 2, calculate the feedforward AGC roll gap adjustment amount according to the thickness deviation specifically as: In the formula: ΔS - Feedforward AGC roll gap adjustment amount (mm); Δh - Stand inlet thickness deviation (mm); M - Strip plasticity coefficient (t / mm); K - Stand elasticity coefficient (t / mm).

4. A feedforward compensation method for the inlet tension in the feedforward thickness control of a cold rolling mill according to claim 1, characterized in that, In the said Step 3, perform a first-order low-pass filter on the roll gap adjustment amount, and the transfer function is: Where: T a - Filter time constant of roll gap adjustment amount (s); T a Set as the time constant of the roll gap adjustment system.

5. A feedforward compensation method for the inlet tension in the feedforward thickness control of a cold rolling mill according to claim 1, characterized in that, In the said Step 4, calculate the actual roll reduction according to the filtered feedforward AGC roll gap adjustment amount: Where: Δh act - The actual roll gap of the feedforward AGC; ΔS' - Filtered roll gap adjustment amount; M - Strip plasticity coefficient (t / mm); K - Stand elasticity coefficient (t / mm).

6. The feedforward compensation method for the inlet tension in the feedforward thickness control of a cold rolling mill according to claim 1, wherein In the said Step 6, use the differential link to convert the inlet line speed compensation amount into the inlet line acceleration compensation amount: where: a corr_FFC - inlet line acceleration compensation amount (m / s 2 ); h - Inlet thickness set value (mm); v - Inlet line speed (m / s); Δv - Inlet line speed compensation amount (m / s); Δh act - Actual roll gap of the feedforward AGC; ΔS' - Filtered roll gap adjustment amount; M - Strip plasticity coefficient (t / mm); K - Stand elasticity coefficient (t / mm).

7. A feedforward compensation method for the inlet tension in the feedforward thickness control of a cold rolling mill according to claim 1, characterized in that In the said Step 7, calculate the torque compensation of the inlet coiler according to the inlet line acceleration compensation: where: a corr_FFC - Inlet line acceleration compensation amount (m / s 2 ); J - Moment of inertia of the entry coiler kg·m 2 ; i - Transmission ratio of the inlet coiler; r - Steel coil radius of the inlet coiler (m).

8. A feedforward compensation system for the inlet tension in the feedforward thickness control of a cold rolling mill, characterized in that, It includes a detection device, a processor, and a coiling motor drive device; The said detection device is used to detect the strip inlet thickness deviation; The said processor receives the detection signal of the detection device, runs the method described in any one of claims 1 - 7, and calculates the inlet strip speed compensation, the inlet line speed compensation, calculates the inlet line acceleration compensation, and the inlet coiling torque compensation; The processor outputs speed and torque signals to the coiling motor drive device, and drives the coiling motor through the coiling motor drive device to adjust the torque to achieve compensation for the strip tension at the entrance of the rack.

9. A processor of a computer, characterized in that, The processor receives the detection signals of the detection device, runs the method described in any one of claims 1-7, calculates the strip speed compensation at the entrance, the inlet line speed compensation, calculates the inlet line acceleration compensation and the inlet coiling torque compensation, and adjusts the torque through the coiling motor to achieve compensation for the strip tension at the entrance of the rack.

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