CN102873106A - Quick and precise elongation control method for temper mill - Google Patents

Abstract

The invention discloses a quick and precise elongation control method for a temper mill. Double closed-loop control systems are adopted by the method, an inner loop control system is responsible for rolling force control, and an outer loop control system is responsible for elongation control including dynamic compensation control. The rolling force closed-loop control system adopts a mode of sum rolling force control and difference rolling force control of an operating side and a transmission side, and a hydraulic cylinder servo valve adopts a leakage compensation integral control mode. An elongation control loop adopts a dynamic variable-gain adaptive control method to calculate deviation of rolling force for correcting controller gain in real time by means of an integral inverse method. A mathematical model between speed fluctuation and elongation is set up aiming at the problem of high fluctuation of the elongation in a decelerating phase, and elongation control is jointly completed by the rolling force pre-control compensation control method and elongation closed loops.

Description

The quick accuracy control method of a kind of planisher percentage elongation

Technical field

The invention belongs to the metallurgical production process automatic field, relate to a kind of elongation controlling means of rolling mill production line planisher.

Background technology

In the cold rolled strip steel production process, percentage elongation is an important technology index of product.The quality of elongation control performance is directly connected to the quality height of product.Because in process of production, percentage elongation have hysteresiss, the time become, non-linear, Mathematical Modeling is difficult to the characteristics such as accurate foundation, especially the rising in the moderating process of planisher, the fluctuation of percentage elongation is larger.Therefore, adopt conventional increment type PID algorithm to be difficult to obtain satisfied control effect." application of Cold-Rolled Strip Temper Mill elongation control system and research " (steel research journal, 2008 Vol.20 No.5) a kind of elongation control system of cold rolling levelling unit has been described, this system is a kind of double closed-loop control system, what interior ring adopted is the roll-force control system, and what outer shroud adopted is elongation control system.And for planisher in acceleration and deceleration or the percentage elongation fluctuation problem when other disturbance occurring, the method for the FEEDFORWARD CONTROL that proposed in double closed-loop control system, to gather way.The method that article proposes has certain effect for control and the disturbance rejection of percentage elongation, but lacks the characteristic of quick real-time response and the control method of stability.

Summary of the invention

Purpose of the present invention just provides a kind of quick accuracy control method of planisher percentage elongation, and the method not only has gratifying elongation control effect, but also has fast real-time response characteristic and the stronger stability of a system.

For achieving the above object, the present invention has adopted following technical scheme:

The quick accuracy control method of a kind of planisher percentage elongation, the method adopts double closed-loop control system, and wherein roll-force control is as interior ring control system, and elongation control comprises dynamic compensation control as the outer shroud control system; The roll-force closed-loop control system adopts is the mode of controlling with roll-force control and poor roll-force of fore side and transmission side; What the hydraulic cylinder servo valve adopted is leakage compensation integration control mode.

Further, described roll-force closed-loop control system has fast response characteristic, and system response time, the roll-force fluctuation range was controlled in the 0.05MN about 25ms.Servo valve output current I:

$I=K_p*\mathrm{\ΔF}+\frac{1}{T_i}\underset{0}{\overset{t}{\∫}}\mathrm{\Δf}*K_p*\mathrm{dt}$

Δ F is the rolling force deviation value in the formula, K _PBe controller gain, T _iBe servo valve leakage compensation controller time of integration, t is the sampling period of program.

Further, described percentage elongation closed-loop control system has fast response characteristic, and system response time, the roll-force fluctuation range was controlled in the 0.05MN about 25ms.

The additional setting value of the roll-force F1 of percentage elongation closed-loop control system output:

$F_1=K_p*\mathrm{\Δ\ϵ}+\frac{1}{T_i}\underset{0}{\overset{t}{\∫}}\mathrm{\Δ\ϵ}*K_p*\mathrm{dt}$

Δ ε is the rolling force deviation value in the formula, K _PBe controller gain, T _iBe elongation control device time of integration, t is the sampling period of program.

Further, percentage elongation closed loop controller gain Kp also comprises adaptive gain K, according to roll-force and percentage elongation relation, the elongation control loop calculates the rolling force setup value in real time by counter the pushing away of integration, and actual roll-force compares according to the proportionality coefficient between drift correction roll-force and the percentage elongation.Proportionality coefficient is transformed gain as the elongation control device, so just can realize dynamically revising continuously of ride gain.

The computational methods of adaptive gain K are as follows:

$K=\frac{1}{T}*\underset{0}{\overset{t}{\∫}}(K_0*\mathrm{\ϵ}-F_0)*\mathrm{dt}$

F in the formula ₀Be the setting value of the roll-force of upper one scan computation of Period, K ₀Be the gain of upper one scan computation of Period, ε: actual percentage elongation, T are the Self Adaptive Control link time of integration, and t is the sampling period of program.

Percentage elongation default control in the lifting speed process: set up the Mathematical Modeling of velocity variations and percentage elongation Relations Among, and then calculate the roll-force value that needs compensation, regulate the release rate variation on the impact of percentage elongation by roll-force; The computing formula of the additional setting value of roll-force compensation F2:

$F_2=k*\frac{\sqrt{V_{\max }}-\sqrt{V_1}}{\sqrt{V_{\max }}-\sqrt{V_0}}$

In the formula: the additional setting value of F2 compensation roll-force, k is velocity feed forward roll-force correction factor, and Vmax is maximum line velocity, and Vl is travel line speed, and V0 is the threading linear velocity.

Compared with prior art, advantage of the present invention is: because the method is except adopting double closed-loop control system, that also adopted the roll-force closed-loop control system and mode roll-force control and poor roll-force control, and the employing of hydraulic cylinder servo valve is leakage compensation integration control mode, and added the adaptive gain control algolithm of percentage elongation closed loop controller, therefore, the control method of this planisher percentage elongation, not only have gratifying elongation control effect, but also have fast real-time response characteristic and the stronger stability of a system.

Description of drawings

Fig. 1 roll-force closed-loop control system schematic diagram.

Fig. 2 percentage elongation closed-loop control system schematic diagram.

Fig. 3 is with the elongation control system schematic diagram of dynamic compensation.

The specific embodiment

Referring to Fig. 1～3, its concrete steps are as follows:

The design of step 1. planisher elongation control system comprises controller soft hardware selection and control system platform building:

Control system hardware is selected the S7-400 of Siemens Company series of PLC and FM458 series of high speed closed loop control module.Select S7-400 to carry out elongation control model selection and start and stop logic, the FM458 module selects the FM448 module to carry out the fieldbus data communication as the elongation control device, selects the FM438 module to process as input/output signal.Laser velocimeter and encoder dual mode are adopted in the percentage elongation test section.Control software adopts Siemens STEP 7 V5.3 and D7 SYS system development environment.

Step 2. planisher percentage elongation detection system:

Adopting laser velocimeter and encoder dual mode to carry out actual percentage elongation detects.Laser velocimeter adopts PROFIBUS DP bus communication mode to be connected with the FM448 module, by bus network frame inlet/outlet strip speed is sent to control system and carries out percentage elongation calculating.Frame inlet/outlet guide roller shaft core position is installed high-precision encoder and is connected with the FM438 module by shielded cable, and the inlet/outlet strip speed is sent to control system.

Step 3. roll-force Close-loop Control System Design:

The roll-force closed-loop control system is regulated as interior ring has fast response characteristic, adopts servo valve to regulate, and the adoption rate controller adds the control mode of servo valve leakage compensation integrator.About system response time 25ms, the roll-force fluctuation range is controlled in 5 tons.Servo valve output current I:

$I=K_p*\mathrm{\ΔF}+\frac{1}{T_i}\underset{0}{\overset{t}{\∫}}\mathrm{\ΔF}*K_p*\mathrm{dt}$

Control parameter value: K _P=1.0, T _i=50s, t=1.6ms.

Step 4. planisher percentage elongation Close-loop Control System Design:

System controls percentage elongation by the roll-force regulative mode, the roll-force regulating loop is as encircling in the system, the percentage elongation closed-loop control is as outer shroud, the elongation control loop adds setting value according to percentage elongation deviation adjusting output roll-force, thereby regulates percentage elongation by the change of press down system roll-force.According to roll-force and percentage elongation relation, the elongation control loop calculates the rolling force setup value in real time by counter the pushing away of integration, and actual roll-force compares according to the proportionality coefficient between drift correction roll-force and the percentage elongation.Proportionality coefficient is transformed gain as the elongation control device, so just can realize dynamically revising continuously of ride gain.

The additional setting value of the roll-force F1 of percentage elongation closed-loop control system output:

$F_1=K_p*\mathrm{\Δ\ϵ}+\frac{1}{T_i}\underset{0}{\overset{t}{\∫}}\mathrm{\Δ\ϵ}*K_p*\mathrm{dt}$

T _i?=500ms，t=6.4ms。

The computational methods of adaptive gain K among the step 5. percentage elongation closed loop controller gain Kp:

Percentage elongation closed loop controller gain Kp also comprises adaptive gain K, according to roll-force and percentage elongation relation, the elongation control loop calculates the rolling force setup value in real time by counter the pushing away of integration, and actual roll-force compares according to the proportionality coefficient between drift correction roll-force and the percentage elongation.Proportionality coefficient is transformed gain as the elongation control device, so just can realize dynamically revising continuously of ride gain.

The computational methods of adaptive gain K among the percentage elongation closed loop controller gain Kp are as follows:

$K=\frac{1}{T}*\underset{0}{\overset{t}{\∫}}(K_0*\mathrm{\ϵ}-F_0)*\mathrm{dt}$

F in the formula ₀Be the setting value of the roll-force of upper one scan computation of Period, K ₀Be the gain of upper one scan computation of Period, K initial value 1.4, T=6000ms, t=6.4ms.

The design of step 6. planisher percentage elongation dynamic compensation controlling unit:

Set up the Mathematical Modeling of velocity variations and percentage elongation Relations Among, and then calculate the roll-force value that needs compensation, regulate the release rate variation on the impact of percentage elongation by roll-force.The additional setting value of roll-force compensation F ₂:

$F_2=k*\frac{\sqrt{V_{\max }}-\sqrt{V_1}}{\sqrt{V_{\max }}-\sqrt{V_0}}$

In the formula: F ₂The additional setting value of compensation roll-force, V _lBe travel line speed, k=1.5, V _Max=1200 m/mins, V ₀=60 m/mins.

Claims (5)

1. quick accuracy control method of planisher percentage elongation, it is characterized in that: the method adopts double closed-loop control system, wherein roll-force control is as interior ring control system, elongation control is as the outer shroud control system, comprise dynamic compensation control, the roll-force closed-loop control system adopts is the mode of controlling with roll-force control and poor roll-force of fore side and transmission side; What the hydraulic cylinder servo valve adopted is leakage compensation integration control mode.

2. the quick accuracy control method of planisher percentage elongation according to claim 1, it is characterized in that: described roll-force closed-loop control system has fast response characteristic, system response time, the roll-force fluctuation range was controlled in the 0.05MN at 25-25ms, servo valve output current I:

$I=K_p*\mathrm{\ΔF}+\frac{1}{T_i}\underset{0}{\overset{t}{\∫}}\mathrm{\Δf}*K_p*\mathrm{dt}$

Δ F is the rolling force deviation value in the formula, K _PBe controller gain, T _iBe servo valve leakage compensation controller time of integration, t is the sampling period of program.

3. the quick accuracy control method of described planisher percentage elongation according to claim 1 is characterized in that: the additional setting value of the roll-force F1 of percentage elongation closed-loop control system output:

$F_1=K_p*\mathrm{\Δ\ϵ}+\frac{1}{T_i}\underset{0}{\overset{t}{\∫}}\mathrm{\Δ\ϵ}*K_p*\mathrm{dt}$

Δ ε is the rolling force deviation value in the formula, K _PBe controller gain, T _iBe elongation control device time of integration, t is the sampling period of program.

4. according to claim 2 or the quick accuracy control method of 3 described planisher percentage elongation, it is characterized in that: described percentage elongation closed loop controller gain Kp also comprises adaptive gain K, according to roll-force and percentage elongation relation, the elongation control loop calculates the rolling force setup value in real time by counter the pushing away of integration, and actual roll-force compares according to the proportionality coefficient between drift correction roll-force and the percentage elongation.Proportionality coefficient is transformed gain as the elongation control device, so just can realize dynamically revising continuously of ride gain;

The computational methods of adaptive gain K are as follows:

$K=\frac{1}{T}*\underset{0}{\overset{t}{\∫}}(K_0*\mathrm{\ϵ}-F_0)*\mathrm{dt}$

F in the formula ₀Be the setting value of the roll-force of upper one scan computation of Period, K ₀Be the gain of upper one scan computation of Period, ε: actual percentage elongation, T are the Self Adaptive Control link time of integration, and t is the sampling period of program.

5. it is characterized in that: also comprise percentage elongation default control in the lifting speed process according to claim 2 or the quick accuracy control method of 3 described planisher percentage elongation; Set up the Mathematical Modeling of velocity variations and percentage elongation Relations Among, and then calculate the roll-force value that needs compensation, regulate the release rate variation on the impact of percentage elongation by roll-force; The computing formula of the additional setting value of roll-force compensation F2:

$F_2=k*\frac{\sqrt{V_{\max }}-\sqrt{V_1}}{\sqrt{V_{\max }}-\sqrt{V_0}}$

In the formula: the additional setting value of F2 compensation roll-force, k is velocity feed forward roll-force correction factor, and Vmax is maximum line velocity, and Vl is travel line speed, and V0 is the threading linear velocity.

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