An automatic control method for hydraulic roll gap in a galvanizing unit

Abstract

This invention relates to an automatic control method for the hydraulic roll gap of an aluminized zinc plating mill. A position tilt closed-loop controller, a combined rolling force closed-loop controller, and a combined position closed-loop controller are logically combined. In position control mode, the outputs of the position tilt closed-loop controller and the combined position closed-loop controller are superimposed and then used as the current input to the proportional valve. This ensures both the stability of the pressing position of the pressing cylinder and the stability of the position tilt on both the operating and transmission sides. In pressure control mode, the outputs of the position tilt closed-loop controller and the combined rolling force closed-loop controller are superimposed and then used as the current input to the proportional valve. This ensures both the stability of the total rolling force and the stability of the position tilt on both the operating and transmission sides. This method effectively suppresses the oscillation of the pressing roll system, overcomes the asynchrony of the pressing cylinders on both sides, results in better strip surface treatment, and minimizes quality defects such as rolling marks and rolling waviness.

Description

Technical Field

[0001] This invention relates to the field of electrical automation technology, and in particular to an automatic control method for the hydraulic roller gap of a galvanizing unit. Background Technology

[0002] The existing hydraulic roll gap automatic control system of the galvanizing line in the cold rolling mill has flaws in its design, which greatly restricts the production of finished products. Problems such as roll jamming, imprinting, and equipment failure frequently occur, becoming a bottleneck restricting the stable operation of the galvanizing process. The original hydraulic roll gap automatic control concept of the finishing machine was as follows:

[0003] 1) The position control of the hydraulic roll gap automatic control adopts independent position control on both sides, without closed-loop position tilt control in between, see Figure 1 The block diagram of the individual position control shown indicates that the position control of the hydraulic roll gap automatic control is an individual position control on both sides, without a closed-loop control for position tilting between them, resulting in a situation of position asynchrony during the hydraulic pressing process;

[0004] 2) The rolling force control of the hydraulic roll gap automatic control adopts separate rolling force control on both sides, without closed-loop control of position tilt and pressure in between, see... Figure 2 The diagram shown is a block diagram of the individual rolling force control. The rolling force control of the hydraulic roll gap automatic control is a separate rolling force control on both sides. During dynamic rolling, there is a situation where the pressure adjustment is not synchronized, resulting in a more violent fluctuation in the force difference.

[0005] 3) Since the position and rolling force are controlled separately, there is a huge disturbance when switching between the position and rolling force, which causes the two sides to press asynchronously and produce defects such as roll jamming.

[0006] The aforementioned design issues lead to a deterioration in the proportional valve's characteristics after a period of use. This deterioration prevents the system from automatically compensating, resulting in asynchronous pressing on both sides and causing roll bearing defects. During finishing, large deviations in rolling force cause roll bearing defects on the steel plate surface, increasing roll wear. Large positional deviations lead to rapid opening, resulting in large quantities of unfinished and unfinished material. After finishing, changes in the roll gap after weld seam finishing cannot be adjusted by the system in time, causing feather-like marks tens of meters long on the strip surface. Replacing the servo valve requires manual readjustment of the controller's PI parameters to optimize the synchronization of pressing on both sides, wasting time. Single-end wear on the support roller easily causes cone-shaped marks, increasing roll wear. Summary of the Invention

[0007] This invention provides an automatic control method for the hydraulic roll gap of a galvanizing mill. By keeping the closed-loop control of the rolling force belt tilt, the closed-loop control of the position belt tilt, and the tilt controller always engaged, it can effectively suppress the swaying of the pressing roll system and overcome the asynchronous phenomenon of the pressing cylinders on both sides. In particular, when the upper and lower roll systems are in contact, the stable roll system contact can effectively suppress the occurrence of roll jamming.

[0008] To achieve the above objectives, the present invention employs the following technical solution:

[0009] An automatic control method for the hydraulic roll gap of an aluminizing and zinc plating unit includes:

[0010] (1) Closed-loop control of rolling force band tilt: Under the condition that the roll gap of the work roll is less than or equal to 1 mm and the rolling force is greater than or equal to 60 t, the closed-loop control of rolling force band tilt is put into operation. The output Y2 of the position tilt closed-loop controller and the output Y1 of the rolling force closed-loop controller are superimposed, and then the analog signal is sent to the servo valve through the analog output board. The input of the proportional valve on the operating side is Y1-Y2 / 2, and the input of the proportional valve on the transmission side is Y1+Y2 / 2, thereby performing closed-loop control of rolling force band tilt of the hydraulic cylinder on the transmission side and the operating side.

[0011] (2) Closed-loop control with tilt at the closing position: The machine preparation position is set to press up 9-11mm, the middle position is set to roll gap 65-75mm, and the slightly open position is set to roll gap 2-4mm. These three positions control the overall position of the pressing cylinder and simultaneously control the tilt. The output Y2 of the tilt closed-loop controller and the output Y3 of the closing position closed-loop controller are superimposed, and then the analog signal is sent to the servo valve through the analog output board. The input of the proportional valve on the operating side is Y3-Y2 / 2, and the input of the proportional valve on the transmission side is Y3+Y2 / 2, thereby performing closed-loop control with tilt at the closing position of the hydraulic cylinder on the transmission side and the operating side.

[0012] (3) Control parameter tuning: PID parameter tuning of tilt closed-loop controller, PID parameter tuning of rolling force closed-loop controller, PID parameter tuning of position closed-loop controller, position control ramp parameter tuning, rolling force control ramp parameter tuning, and tilt control ramp parameter tuning.

[0013] Furthermore, the control parameters are tuned by performing proportional, integral, and derivative calculations based on the deviation between the parameter setpoint and the actual feedback, and outputting a correction for the deviation between the actual value and the setpoint.

[0014] Furthermore, during the closed-loop control of the inclined position, the pressing cylinder moves upward so that the work roll and the support roll come into contact with each other and then close to form a rolling force.

[0015] Furthermore, the roll gap is controlled to be 0–3 mm.

[0016] Furthermore, the rolling force is controlled to be 60-800t.

[0017] Furthermore, the tilt control position adjustment range is 0–2 mm.

[0018] Furthermore, the position and rolling force of the finishing mill are acquired using a magnetic ruler displacement sensor and a pressure sensor.

[0019] Furthermore, the servo valve is a bipolar proportional servo valve with an integrated valve body and valve plate.

[0020] Furthermore, the hardware of the automatic control system for the roll gap of the finishing machine includes a hydraulic cylinder, a servo valve platform, an oil tank, a hydraulic pump, servo valves, and a control system. The oil tank is connected to the hydraulic pump through a pipeline, and the output pipeline of the hydraulic pump is connected to the hydraulic cylinder through a servo valve. All servo valves are integrated on the servo valve platform, and the power lines of the servo valves are connected to the control system.

[0021] Furthermore, the control system includes a CPU, a digital input / output module, an analog input / output module, and a high-speed communication module.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) Upgrade the existing individual rolling force and individual position control to combined rolling force with tilt closed-loop control and combined position with tilt closed-loop control;

[0024] 2) The tilt controller is always engaged, which can effectively suppress the swaying of the pressing roller system and overcome the asynchrony of the pressing cylinders on both sides;

[0025] 3) When the upper and lower rollers are in contact, stable roller contact can effectively suppress the formation of rolling marks, allowing the finishing machine to be put into and withdrawn from the working position smoothly, thus resulting in a good surface treatment effect for the strip steel and minimizing quality defects such as rolling marks and rolling ripples. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of traditional single-position control.

[0027] Figure 2 This is a schematic diagram of traditional single rolling force control.

[0028] Figure 3 This is a schematic diagram of the closed-loop control of the rolling force strip tilt described in this invention.

[0029] Figure 4 This is a schematic diagram of the closed-loop control with tilt at the desired position as described in this invention. Detailed Implementation

[0030] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0031] This invention discloses an automatic control method for the hydraulic roll gap of a zinc plating unit, comprising:

[0032] (1) See Figure 3Combined rolling force belt tilt closed-loop control: Under the condition that the roll gap of the work roll is less than or equal to 1 mm and the rolling force is greater than or equal to 60 t, the combined rolling force belt tilt closed-loop control is put into operation. At this time, the combined rolling force and the position tilt are controlled at the same time. The two are independent closed-loop control. Then, the outputs of their respective closed-loop controllers are superimposed, and the ±20mA signal is sent to two servo valves through the analog output board, thereby controlling the hydraulic cylinders on the transmission side and the operating side to achieve the combined rolling force belt tilt closed-loop control. In the pressure control mode, the output Y2 of the position tilt closed-loop controller and the output Y1 of the combined rolling force closed-loop controller are superimposed, and the analog signal is sent to the servo valve through the analog output board. The input of the proportional valve on the operating side is Y1-Y2 / 2, and the input of the proportional valve on the transmission side is Y1+Y2 / 2, thereby performing the combined rolling force belt tilt closed-loop control of the hydraulic cylinders on the transmission side and the operating side.

[0033] (2) See Figure 4 Closed-loop control with tilt at the closing position: The machine preparation position is set with a pressing cylinder of 10mm, the middle position with a roll gap of 70mm, and the slightly open position with a roll gap of 3mm. These three positions control the overall position of the pressing cylinder and simultaneously control the tilt. The two are independent closed-loop controls. The outputs of their respective closed-loop controllers are superimposed, and then ±20mA signals are sent to two servo valves through the analog output board. This controls the hydraulic cylinders on the transmission side and the operating side to achieve closed-loop control with tilt at the closing position. The outputs Y2 of the tilt closed-loop controller and Y3 of the closing position closed-loop controller are superimposed, and then analog signals are sent to the servo valves through the analog output board. The input of the proportional valve on the operating side is Y3-Y2 / 2, and the input of the proportional valve on the transmission side is Y3+Y2 / 2. This achieves closed-loop control with tilt at the closing position of the hydraulic cylinders on the transmission side and the operating side. During the closed-loop control with tilt at the closing position, the pressing cylinder moves upward so that the work roll and the support roll contact each other and then close to form a rolling force.

[0034] (3) Control parameter tuning: PID parameter tuning of tilt closed-loop controller, PID parameter tuning of rolling force closed-loop controller, PID parameter tuning of position closed-loop controller, position control ramp parameter tuning, rolling force control ramp parameter tuning, and tilt control ramp parameter tuning.

[0035] The design principle of the position tilt closed-loop controller is based on the requirement of the incoming plate shape. The operator manually adjusts the roll gap tilt to adapt to the needs of the plate shape and achieve the requirements of the steel plate surface treatment. The core part of this controller is a PID controller. Based on the deviation between the set value and the actual feedback, it performs proportional, integral and derivative calculations, and then outputs a correction to the deviation between the actual value and the set value, so that the actual value quickly follows the set value.

[0036] The design principle of the closed-loop controller for rolling force is to maintain a certain rolling force during the rolling process, and then make PID control adjustments based on the actual rolling force feedback.

[0037] According to the design principle of the closed-loop controller for the position, when the whole machine is in position control, the pressing cylinder needs to move upward so that the work roll and the support roll come into contact with each other and then close to form a rolling force.

[0038] The three closed-loop controllers are logically combined. In position control mode, the outputs of the position tilt closed-loop controller and the combined position closed-loop controller are superimposed and used as the current input of the proportional valve. This ensures both the stability of the pressing position of the pressing cylinder and the stability of the position tilt on both the operating and transmission sides. In pressure control mode, the outputs of the position tilt closed-loop controller and the combined rolling force closed-loop controller are superimposed and used as the current input of the proportional valve. This ensures both the stability of the total rolling force and the stability of the position tilt on both the operating and transmission sides.

[0039] The roll gap is controlled to be 0-3mm, the rolling force is controlled to be 60-800t, and the tilt control position is adjusted to be 0-2mm.

[0040] The hardware of the automatic roll gap control system for the finishing mill includes hydraulic cylinders, servo valve platforms, oil tanks, hydraulic pumps, servo valves, and a control system. The oil tank is connected to the hydraulic pump via pipelines, and the output pipeline of the hydraulic pump is connected to the hydraulic cylinder via servo valves. All servo valves are integrated on the servo valve platform. The servo valves are bipolar proportional servo valves with an integrated valve body and valve plate. The power lines of the servo valves are connected to the control system. The control system includes a CPU, digital input / output modules, analog input / output modules, and a high-speed communication module. The position and rolling force of the finishing mill are acquired using magnetic scale displacement sensors and pressure sensors. The signal lines of the magnetic scale displacement sensors and pressure sensors are connected to the analog input / output module interface. The PLC is a Siemens S7-400 CPU416-2DP. The PLC mainly performs HGC control, AEC control, sequential control, signal input / output, and communication with other control systems. The two CPUs each undertake different tasks. One CPU416-2DP performs the sequential control function, while the other CPU416-2DP performs the HGC and AEC functions. The CPU416-2DP outputs rolling force, position commands, and elongation, and receives their feedback signals to form a feedback closed-loop control system.

[0041] The following embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments. Unless otherwise specified, the methods used in the following embodiments are conventional methods.

[0042]

Example

[0043] 1) Based on the S7-416 CPU hardware and Step7 software platform, a position tilt closed-loop controller is set up;

[0044] 2) Based on the S7-416 CPU hardware and Step7 software platform, a closed-loop controller for the combined rolling force was set up;

[0045] 3) Based on the S7-416 CPU hardware and Step7 software platform, set up a closed-loop controller for the final position;

[0046] The design principle of the position tilt closed-loop controller is based on the requirement of the incoming plate shape. The operator manually adjusts the roll gap tilt to adapt to the needs of the plate shape and achieve the requirements of the steel plate surface treatment. The core part of this controller is a PID controller. Based on the deviation between the set value and the actual feedback, it performs proportional, integral and derivative calculations, and then outputs a correction to the deviation between the actual value and the set value, so that the actual value quickly follows the set value.

[0047] The design principle of the closed-loop controller for rolling force is to maintain a certain rolling force during the rolling process, and then make PID control adjustments based on the actual rolling force feedback.

[0048] According to the design principle of the closed-loop controller for the position, when the whole machine is in position control, the pressing cylinder needs to move upward so that the work roll and the support roll come into contact with each other and then close to form a rolling force.

[0049] Three closed-loop controllers are logically combined. In position control mode, the output Y2 of the position tilt closed-loop controller and the output Y1 of the combined position closed-loop controller are superimposed and used as the current input of the proportional valve. Specifically, the input of the proportional valve on the operating side is Y1-Y2 / 2, and the input of the proportional valve on the transmission side is Y1+Y2 / 2. This ensures both the stability of the pressing position of the pressing cylinder and the stability of the position tilt on both the operating and transmission sides. In pressure control mode, the output Y2 of the position tilt closed-loop controller and the output Y3 of the combined rolling force closed-loop controller are superimposed and used as the current input of the proportional valve. Specifically, the input of the proportional valve on the operating side is Y3-Y2 / 2, and the input of the proportional valve on the transmission side is Y3+Y2 / 2. This ensures both the stability of the total rolling force and the stability of the position tilt on both the operating and transmission sides.

[0050] The PLC adopts a Siemens S7-400 CPU416-2DP PLC control system, which mainly completes HGC control, AEC control, sequential control, signal input / output, and communication with other control systems. The PLC analog input module is model 6ES7431-1KF00-0AB0, an 8-channel 13-bit module with a response time of 16.7 / 20ms. The analog output module is model 6ES7432-1HF00-0AB0, an 8x13-bit module with a response time of 300us. The two CPUs each perform different tasks. One CPU416-2DP completes the sequential control function, while the other CPU416-2DP completes the HGC and AEC functions. The CPU416-2DP outputs rolling force, position commands, and elongation, and receives their feedback signals to form a feedback closed-loop control system.

[0051] The hardware of the automatic roll gap control system for the finishing machine includes a hydraulic cylinder, a servo valve platform, an oil tank, a hydraulic pump, servo valves, and a control system. The oil tank is connected to the hydraulic pump via a pipeline, and the output pipeline of the hydraulic pump is connected to the hydraulic cylinder via a servo valve. All servo valves are integrated on the servo valve platform. The servo valves are bipolar proportional servo valves with an integrated valve body and valve plate. The power lines of the servo valves are connected to the control system. The main performance parameters of the automatic roll gap control system for the finishing machine are as follows:

[0052] (1) Hydraulic cylinder: maximum stroke 350mm, effective stroke 300mm;

[0053] (2) Rolling force: Maximum value of 500t for a single hydraulic cylinder;

[0054] (3) Hydraulic source pressure provided by hydraulic pump: high pressure 260 bar, low pressure 110 bar;

[0055] (4) Hydraulic pump: flow rate 230L / min, pressure 260bar, number 2, one working and one standby;

[0056] (5) Proportional servo valve: rated flow 40L, quantity 2;

[0057] (6) Hydraulic cylinder: 800mm in diameter, 5026cm2 in cross-sectional area, 230bar in working pressure, 800t in maximum rolling force, 2mm / s in short-stroke speed under acceleration, 12mm / s in long-stroke speed, 2 in number, one in operation and one in standby.

[0058] In addition, the position and rolling force acquisition of the whole machine adopts TEMPOSONIC magnetic scale displacement sensor and HDA3844 pressure sensor. TEMPOSONIC magnetic scale displacement sensor has the advantages of strong anti-interference ability, resolution up to 1μm, response time of only 0.5ms, and stroke of 350mm; HDA3844 pressure sensor has the advantages of strong anti-interference ability, resolution up to 0.01bar, response time of only 1ms, and measurement range: 4~20mA corresponding to 0~400bar.

[0059] Production tests were conducted on finished materials of different specifications and materials. A total of 200 rolls of finished materials were produced, each roll weighing approximately 20 tons. Distinguished by thickness: 55 rolls were thicker than 2.0mm, including 13 rolls of the extreme thickness of 2.4mm to 2.5mm; 60 rolls were of intermediate thickness (1.0mm to 2.0mm); and 85 rolls were of thin material (below 1.0mm). Distinguished by width: 47 rolls were of 1m to 1.15m width; 123 rolls were of 1.2m to 1.4m width; and approximately 30 rolls were of the extreme width of 1.5m. Distinguished by material: 116 rolls were of CQ (CS B, DX51D+Z); 4 rolls were of DQ (DX52D+Z); and 80 rolls were of DDQ (DX53D+Z, SGCD3, ST04Z). All specifications produced by the galvanizing line were included.

[0060] When the rolling mill was put into operation and removed, the rolling force difference fluctuation was 3t and the position tilt parameter fluctuation was 0.01mm, which were relatively small. There were no large abnormal fluctuations. The system was put into operation and removed from the working position very smoothly. The surface treatment effect of the strip steel was good, and there were no quality defects such as rolling marks and rolling wavy shapes. In contrast, the original traditional control mode had very large force difference and tilt fluctuation at the moment of operation, with a tilt fluctuation of 0.5mm and a force difference fluctuation of 20 tons.

[0061] During the finishing process of the weld seam, with a specification of 0.368mm to 0.412mm, rolling force of 300t, tilt of 0.56mm, and bending roll of 60t, the control system remained stable. The surface of the steel plate before and after the weld seam finishing was normal, without any minor marks or other defects. During normal rolling, with the rolling force increased to 400 tons, the tilt adjusted to 0.56mm, and the bending roll of 70t, no abnormalities were observed on the surface of the steel plate. However, the rolling force fluctuated drastically at certain times, which was improved by adjusting the tilt position.

[0062] When thick materials and extreme grades pass through the weld seam, for materials with a thickness of 1.7mm to 2.0mm, when the weld seam is finished, the rolling force is kept at 230t without reducing it, with an inclination of 1.0mm and a force difference of -15t. No marks appear on the weld seam during the finishing process, and the system control tends to be stable. When the 2.5mm weld seam passes through the finishing machine, the inclination remains unchanged at 0.97mm. The operator reduces the rolling force from 220t to 160t and dynamically adjusts the weld seam during the finishing process. The steel plate surface is normal and no defects such as marks appear.

[0063] When rolling the 2.5mm extreme grade material normally, the rolling force was increased to 220t, the tilt was adjusted to 1.0mm, and the bending roll was 50t. No abnormalities were found on the surface of the steel plate. Only the rolling force fluctuated more violently at certain times. This was quickly improved by adjusting the position and tilt.

[0064] Through this test, the new control mode of the optical unit can meet the requirements of field use and has greatly improved the control accuracy. For example, when deploying and withdrawing the optical unit, the disturbances of force difference and position deviation are very small, the system control tends to be stable, and the problems that existed before can be overcome and improved.

[0065] Through this test, the control mode described in this invention can meet the field requirements of the optical unit and greatly improve the control accuracy. For example, when deploying and retracting the optical unit, the disturbances of force difference and position deviation are very small, the system control tends to be stable, and the problems that existed before can be overcome and improved.

[0066] After the operation mode of the finishing machine was modified to tilt control, and the unit started producing zinc-free finished products, the variety of products processed by the unit is now quite rich. The main specifications include CQ products with a thickness of less than 0.5mm, DDQ and CQ products with a width of more than 1400mm, and DDQ products with a thickness of more than 2.0mm. Overall, the operation mode described in this invention is superior to the original traditional control mode in terms of both control concept and actual effect, and effectively avoids the occurrence of various problems such as roller jamming and imprinting.

[0067] After implementation, the defects of the embossing on the surface of the steel plate after each operation of the finishing machine and weld seam were basically eliminated. The embossing caused by plate shape and plate difference issues disappeared quickly after tilting adjustment, which greatly improved the product yield. In addition, the new hydraulic roller gap automatic control concept has an automatic compensation function. After replacing the proportional valve, there is no need to readjust the PI control parameters, which shortens the accident handling time and effectively improves the equipment operation rate.

[0068] By upgrading and improving the automatic control concept and auxiliary facilities of the hydraulic roller gap of the finishing machine, the number of failures of the finishing machine is reduced by 2 per month. Each failure reduces the amount of waste products caused by finishing marks, parking cloud patterns, and excessive material pulling during startup by 9.6 tons. The price difference between good products and waste products is 2880.47 yuan / ton, so the annual increase in benefits is 2*12*9.6*2880.47=663,600 yuan.

Claims

1. An automatic control method for the hydraulic roll gap of a zinc plating unit, characterized in that, include: (1) Closed-loop control of rolling force band tilt: Under the condition that the roll gap of the work roll is less than or equal to 1 mm and the rolling force is greater than or equal to 60 t, the closed-loop control of rolling force band tilt is put into operation. The output Y2 of the position tilt closed-loop controller and the output Y1 of the rolling force closed-loop controller are superimposed, and then the analog signal is sent to the proportional servo valve through the analog output board. The input of the proportional servo valve on the operating side is Y1-Y2 / 2, and the input of the proportional servo valve on the transmission side is Y1+Y2 / 2, thereby performing closed-loop control of rolling force band tilt of the hydraulic cylinder on the transmission side and the operating side. (2) Closed-loop control with tilt at the closing position: The machine preparation position is set to press up 9-11mm, the middle position is set to roll gap 65-75mm, and the slightly open position is set to roll gap 2-4mm. These three positions control the total position of the pressing cylinder and control the tilt at the same time. The output Y2 of the tilt closed-loop controller and the output Y3 of the closing position closed-loop controller are superimposed, and then the analog signal is sent to the proportional servo valve through the analog output board. The input of the proportional servo valve on the operating side is Y3-Y2 / 2, and the input of the proportional servo valve on the transmission side is Y3+Y2 / 2, thereby performing closed-loop control with tilt at the closing position of the hydraulic cylinder on the transmission side and the operating side. (3) Control parameter tuning: PID parameter tuning of tilt closed-loop controller, PID parameter tuning of rolling force closed-loop controller, PID parameter tuning of position closed-loop controller, position control ramp parameter tuning, rolling force control ramp parameter tuning, and tilt control ramp parameter tuning.

2. The automatic control method for hydraulic roll gap of a galvanizing unit as described in claim 1, characterized in that, The position tilt closed-loop controller performs proportional, integral, and derivative calculations based on the deviation between the parameter setpoint and the actual feedback, and outputs a correction for the deviation between the actual value and the setpoint.

3. The automatic control method for hydraulic roll gap of a galvanizing unit as described in claim 1, characterized in that, During the closed-loop control of the inclined position, the pressing cylinder moves upward so that the work roll and the support roll come into contact with each other and then close to form a rolling force.

4. The automatic control method for hydraulic roll gap of a galvanizing unit as described in claim 1, characterized in that, The rolling force is controlled to be 60-800t.

5. The automatic control method for hydraulic roll gap of a galvanizing unit as described in claim 1, characterized in that, The proportional servo valve is a bipolar proportional servo valve with an integrated valve body and valve plate.

6. The automatic control method for hydraulic roll gap of a galvanizing unit as described in claim 1, characterized in that, The hardware of the automatic control system for the roll gap of the finishing machine includes a hydraulic cylinder, a servo valve platform, an oil tank, a hydraulic pump, servo valves, and a control system. The oil tank is connected to the hydraulic pump through a pipeline, and the output pipeline of the hydraulic pump is connected to the hydraulic cylinder through the servo valve. All servo valves are integrated on the servo valve platform, and the power lines of the servo valves are connected to the control system.

7. The automatic control method for hydraulic roll gap of a galvanizing unit as described in claim 6, characterized in that, The control system includes a CPU, a digital input / output module, an analog input / output module, and a high-speed communication module.

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