Dynamic decoupling control method for hot tandem flying shear based on feedforward

Abstract

This invention belongs to the field of metallurgical automation control technology, and provides a dynamic decoupling control method for hot continuous rolling shear based on feedforward. It includes decoupling the data link between the process control level and the basic automation level, using the steel grade identifier and target thickness as a two-dimensional feedforward trigger state machine nonlinear branch decoupling, and automatically calculating the combined boundary commands of each electromechanical actuator, including target speed, lead rate, blade gap, and auxiliary tension state. Simultaneously, it is supplemented by dynamic length compensation phase angle correction and physical wear integral life warning based on heavy-load conditions. This invention eradicates shearing defects from a physical level, breaks through the bottleneck of low-speed operation in the production line, and significantly improves the shearing accuracy and intelligent operation and maintenance level of the equipment.

Description

Technical Field

[0001] This invention belongs to the field of industrial automation process control and metallurgical machinery equipment control technology. It relates to the dynamic decoupling of electromechanical multidimensional parameters, auxiliary equipment control, and predictive maintenance of the tool throughout its entire life cycle during the shearing process of metal strips with different rheological properties. Specifically, it is a dynamic decoupling control method for hot continuous rolling flying shear based on feedforward. Background Technology

[0002] In hot strip rolling production lines, the flying shear is a core piece of equipment located between the roughing and finishing mills. Its main function is to cut the head, tail, or perform emergency shearing on the intermediate billets during operation, ensuring that the strip enters the finishing mill with a regular end face. As the steel industry continues to increase its requirements for product quality and production pace, the control precision and stability of the flying shear system directly determine the overall yield and operating rate of the line.

[0003] However, existing hot strip rolling flying shear control technology still has the following significant problems in practical industrial applications: 1. The control architecture suffers from data gaps and lacks feedforward awareness of material properties. Traditional flying shear control often employs a unidirectional speed feedback mode based on the basic automation level (L1). Because the L1 system cannot perceive the metallurgical properties of the strip steel (such as steel grade codes) issued by the process control level (L2) in real time, the system can only adopt a rigid, one-size-fits-all parameter setting. When dealing with steel grades with significantly different mechanical properties, the system cannot perform differentiated kinematic modeling.

[0004] 2. Shear instability is a prominent problem in special steel grades (such as 409 and 430 soft stainless steel). Ferritic stainless steel exhibits extremely low deformation resistance in the high-temperature phase transformation region. Under current technology, when flying shears cut this type of soft steel, excessively high shearing speed, improper feed ratio matching, or excessive shear blade clearance often lead to severe plastic rheology and dislocation tearing of the material at the moment of shearing, causing faults such as "the cut head and tail being lifted" or "uncuttable," which in turn can cause steel pile-up or strip breakage accidents in the finishing mill.

[0005] 3. The equipment coordination dimension is singular, lacking a fixed dynamic attitude. Existing technologies are limited to speed optimization of the flying shear's main motor, neglecting the stabilizing effect of auxiliary equipment (such as the hot coil box pinch rolls) on the strip tension and geometric orientation during shearing transients. When shearing soft, thick strip blanks, the lack of cross-regional interlocking protection logic makes it difficult to guarantee the flatness of the sheared section.

[0006] 4. Blindly defined tool maintenance methods and a lack of accurate lifespan assessment. Currently, industrial sites commonly use experience-based blade replacement methods based on fixed time cycles or rated steel tonnage. This method cannot distinguish the non-linear wear differences of blades caused by different steel types (such as conventional steel and high-strength pipeline steel). For example, the impact stress on shear blades from thick pipeline steel is far greater than that of ordinary steel. If traditional experience indicators are used, it is very easy for the shear blade to break due to excessive wear, or for frequent and blind blade replacement to cause downtime and waste of spare parts.

[0007] Therefore, how to construct a flying shear control system that can deeply integrate the metallurgical characteristics of strip steel, realize multi-dimensional dynamic decoupling of electromechanical components, and achieve intelligent operation and maintenance has become a key technical problem that urgently needs to be solved in the current hot rolling field. Summary of the Invention

[0008] The purpose of this invention is to provide a dynamic decoupling control method for hot continuous rolling mill flying shear based on feedforward, so as to overcome the defects of existing flying shear control architecture such as data fragmentation, shear instability of special steel grades, and blind operation and maintenance mode.

[0009] The technical solution adopted by the present invention to achieve the above objectives is as follows: A dynamic decoupling control method for hot continuous rolling mill flying shear based on feedforward includes: S1. Connect the data link between the process control level and the basic automation level, and send out the "steel grade identification code" and "target thickness of intermediate billet" as a two-dimensional feedforward matrix; S2, the basic automation-level main control unit performs nonlinear state machine decoupling based on a two-dimensional feedforward matrix and state machine model, and automatically calculates the combined boundary commands of each electromechanical actuator, including target speed, lead rate, blade clearance and auxiliary tension state; S3. Multi-dimensional execution and collaborative control: This includes the flying shear main drive frequency converter that communicates with the basic automation level, the shear blade gap adjustment, and the external auxiliary unit hot roll box pinch roller control. Each actuator receives decoupling commands issued by the state machine model at the moment of engagement and implements collaborative actions.

[0010] Furthermore, the state machine model receives two-dimensional feedforward features and, based on preset material rheological criteria, performs nonlinear shunting matching and dynamic parameter decoupling on the current shearing condition in real time.

[0011] Furthermore, specifically including: When identified as soft steel with specific low deformation resistance and a thickness ≥38mm, the system executes a combined electromechanical and rigid protection chamber command, including: Set a speed clamp to forcibly lock the main motor's target speed to a stable operating baseline; The CNC command clearance adjustment mechanism precisely locks the horizontal backlash of the cutting tool to the minimum limit value by adjusting the minimum clearance. The interlocking auxiliary machine presses down and simultaneously sends a cross-regional interlocking command to the hot coil box. During the shearing transient command, the pinch rolls quickly drop down and press down on the strip. The posture is stabilized by applying auxiliary calming tension to the rear of the strip. Combined with a high lead rate, the defects at the beginning and end of the soft steel strip are completely eliminated from the physical mechanism. When the feature vector does not meet the above specific conditions, the system terminates the above physical constraints and speeds up operation.

[0012] Furthermore, regardless of the path chosen, the calculated target speed command must enter the dynamic length compensation integrator before being issued. This integrator performs continuous time integration on the large inertial response lag of the heavy machinery transmission chain caused by speed change, corrects the initial phase in real time, and ensures the positioning accuracy of the tangent point.

[0013] Furthermore, an independent equivalent wear integral calculation model is established, and the highest wear weight factor is assigned to the most destructive extreme heavy load conditions based on the feedforward steel grade and cross-sectional area; the single shear equivalent is accumulated at high frequency, and a rigid blade replacement early warning interlock is triggered when the physical fatigue critical threshold is reached.

[0014] The beneficial effects of this invention are: 1. Completely eliminates shear instability defects in specific soft metals, significantly improving yield and safety; This invention breaks through the limitations of traditional constant process parameters. For ferritic stainless steels such as 409 and 430, which are prone to high-temperature plastic rheology, it pioneers a five-dimensional rigid protection system of "reduced speed and step size, minimal side clearance, high lead rate, and auxiliary machine stabilization". Starting from the underlying mechanism of physical rheology, this solution instantly cuts off the lattice slip lines of soft metals and uses the auxiliary tension of cross-regional downward pressure to offset the shear distortion force, completely eliminating the malignant defects such as "head and tail", "burrs" and "section tearing" that have long plagued the industry. It eliminates major production accidents such as steel pile-up and strip breakage in the finishing mill caused by these defects from the source.

[0015] 2. Successfully decoupled complex operating conditions, completely eliminating production line capacity constraints; By introducing a two-dimensional data feedforward architecture, this invention endows the basic automation-level system with advanced state perception and nonlinear decoupling capabilities. This method successfully eliminates the drag on the maximum operating speed of the entire production line caused by a very small number of difficult-to-cut soft steels, enabling the production line to operate independently and stably in a high-throughput cutting state around the clock when facing conventional deformation-resistant strip steel. This breakthrough greatly releases the macroscopic throughput potential of the hot continuous rolling production line, and the overall production cycle time and equipment utilization rate of the entire line are significantly improved.

[0016] 3. Overcome the dynamic response lag of large inertia machinery and achieve millimeter-level high-precision shearing under variable speed conditions; To address the issue of significant lag in the response of heavy machinery transmission chains caused by frequent switching between different operating conditions, this invention creatively introduces a Dynamic Length Compensation (DLC) integral algorithm. By performing high-frequency integration on the transient speed difference and correcting the crankshaft advance compensation angle in the reverse direction, the system completely eliminates the tangent point phase angle drift caused by physical inertia, ensuring that the length positioning accuracy of the cut-off head and tail is always controlled within the extreme tolerance range of ±1mm under any complex speed change scenario, significantly reducing the metal cutting loss rate.

[0017] 4. Revolutionizes the traditional blind maintenance model, enabling predictive intelligent operation and maintenance of high-load tools; This invention abandons the crude "fixed time / fixed tonnage" tool changing mode in industrial sites and innovatively establishes a microscopic wear integral force calculation model based on the actual cutting stress and geometric cross-sectional area of ​​steel grades. By locking the hard fatigue threshold for highly destructive heavy-load working conditions, it achieves a generational leap from "post-event experience-based maintenance" to "Industry 4.0 data-driven predictive maintenance". This mechanism not only effectively prevents abnormal tool breakage and damage caused by exceeding the service life, but also eliminates the waste of expensive spare parts caused by blindly replacing tools in advance, greatly reducing the overall operation and maintenance cost of the entire production line. Attached Figure Description

[0018] Figure 1 This is the architectural logic diagram of the method of the present invention. Detailed Implementation

[0019] The present invention will be further described below with reference to embodiments: A dynamic decoupling control method for hot continuous rolling mill flying shear based on feedforward, such as Figure 1 As shown, it includes: S1. Connect the data link between the process control level and the basic automation level, and send out the "steel grade identification code" and "target thickness of intermediate billet" as a two-dimensional feedforward matrix; S2, the basic automation-level main control unit performs nonlinear state machine decoupling based on a two-dimensional feedforward matrix and state machine model, and automatically calculates the combined boundary commands of each electromechanical actuator, including target speed, lead rate, blade clearance and auxiliary tension state; The state machine model receives two-dimensional feedforward features and performs nonlinear shunting matching and dynamic parameter decoupling for the current shearing condition in real time based on preset material rheological criteria.

[0020] Specifically, it includes: When identified as ferritic stainless steels such as 409 and 430, which are highly susceptible to high-temperature plastic flow, and with a thickness of nearly 38 mm, the system executes a combined electromechanical and rigid protection chamber command, including: Set a speed clamp to forcibly lock the main motor's target speed to a stable operating reference, and reduce the shear linear velocity to 1.1 m / s; The CNC command gap adjustment mechanism precisely locks the horizontal backlash of the cutting tool to a minimum limit value of 0.45 to suppress drawing and avoid transient brittle fracture. The interlocking auxiliary machine presses down and simultaneously sends a cross-regional interlocking command to the hot coil box. During the shearing transient command, the pinch rolls quickly drop down and press down on the strip. The posture is stabilized by applying auxiliary calming tension to the rear of the strip. Combined with a large advance rate (feed ratio 15%), the defects at the beginning and end of the soft steel strip are completely eliminated from the physical mechanism. When the eigenvector does not meet the above specific conditions, for conventional steel grades with a thickness ≤36mm, the basic speed step is increased to 1.3m / s and the adaptive closed-loop feed ratio is implemented.

[0021] Meanwhile, phase angle integral compensation (DLC) is introduced to correct the speed change lag, and a wear calculation model based on specific steel grades is established to realize rigid blade switching early warning.

[0022] Regardless of the path chosen, the calculated target speed command must enter the dynamic length compensation integrator before being issued. This integrator continuously integrates the large inertial response lag of the heavy machinery transmission chain caused by speed change, corrects the initial phase in real time, and ensures the accuracy of the tangent point positioning.

[0023] An independent equivalent wear integral calculation model is established. Based on the feedforward steel grade and cross-sectional area, the highest wear weight factor is assigned to the most destructive extreme heavy load conditions. The single shear equivalent is accumulated at high frequency, and a rigid blade replacement early warning interlock is triggered when the physical fatigue critical threshold is reached.

[0024] The rigid motion boundaries of each actuator are defined by the following physical and mathematical model, specifically including: 1. Based on the two-dimensional feedforward characteristics, calculate and distribute the target value of the shear linear velocity in real time. :

[0025] The formula reduces the transient deformation energy of mild steel from a physical mechanism, preventing plastic drawing; at the same time, it reduces the transient deformation energy of mild steel from a physical mechanism, preventing plastic drawing; Release conventional strip steel production capacity.

[0026] 2. The system drives an eccentric mechanism to adjust the horizontal backlash of the blade. High-frequency adjustment, CNC compensation equation for shear blade gap:

[0027] When 409 / 430 mild steel is retrieved, the system calls the minimum tolerance coefficient. Force the side clearance to be locked. The extreme micro-gap creates a highly concentrated transient brittle shear stress field, instantly cutting off the metal slip line and eliminating burrs on the cross-section.

[0028] Dynamic length compensation (DLC) phase angle integral control; To overcome the hysteresis caused by the speed jump (from 1.1 m / s to 1.3 m / s), the system calculates the crankshaft advance compensation angle in real time. :

[0029] Transient speed measurement of strip steel (Superimposed with f=15% lead rate) and motor linear velocity The dynamic deviation is continuously integrated over time and fed back into the driver to completely eliminate the millimeter-level tangent error caused by large inertia.

[0030] 4. Predictive maintenance model based on real cutting loads; Establish the equivalent total fatigue value based on the accumulation of micro-wear in a single event. Evaluation equation:

[0031] Principle: For highly destructive working conditions (such as setting h=26mm pipeline steel), the system assigns an extremely high wear weight. When the high-frequency accumulation detects that the actual number of sheared blocks reaches n=130, a decision is made. The material fatigue threshold has been reached, and an interlocking mechanism is immediately triggered to force a blade change, eliminating the risk of unexpected downtime at its source.

[0032] The method of this invention aims to solve the complex multivariable problem of flying shear control in hot rolling process. Traditional flying shear control usually relies only on feedback, that is, measuring the actual results through sensors and correcting errors accordingly. However, this often lags in response to rapid changes and complex disturbances (such as temperature changes, different material properties, and speed fluctuations).

[0033] The system first acquires various real-time process features from multiple sensors. These features are not singular but multi-source, including: (1) Temperature characteristics, thickness characteristics, and speed characteristics: the current physical and motion state of the strip steel.

[0034] (2) Shear force characteristics and material properties: provide important information about the energy required for the shearing process itself and the mechanical behavior of the strip.

[0035] (3) Equipment status: Monitor the health and performance status of the actuators. All of this feedforward data is sent to the control layer.

[0036] Control Layer - Feedforward and Decoupling: (1) Feedforward control branch: Using the acquired feature data, predict future disturbances and system requirements to generate a "feedforward compensation signal". For example, if the feedforward detects that the upcoming strip is thicker, the feedforward controller will increase the preload of the shear force in advance, thereby mitigating the impact of the disturbance before it occurs.

[0037] (2) Dynamic decoupling control branch: handles the mutual influence between control variables. For example, changes in material properties and temperature may simultaneously affect the shear force demand and the system response speed. The decoupling controller runs the "decoupling algorithm matrix" and "decoupling control algorithm" to separate these interrelated influences and generate "decoupling control signals", thereby achieving independent and more precise control of multiple parameters.

[0038] (3) Central Integrated Control and Execution: The "Central Integrated Control Unit" receives signals from the feedforward and decoupled branches, combines them to generate "integrated control commands" to drive execution. These integrated commands take into account the compensation for prediction and the correction for decoupling, thereby producing a more optimized and precise shearing action.

[0039] (4) Auxiliary functions and monitoring: Fault diagnosis, parameter optimization and user interface provide additional system monitoring and dynamic adjustment capabilities.

[0040] (5) Process feedback path: The sensor monitors the actual flying shear and sends the feedback back to the system to close the feedback loop. At the same time, it provides real-time data for feedforward and decoupling calculation, thus forming a complete adaptive control system.

[0041] This invention constructs a data penetration link between the process control level and the basic automation level, using the strip steel's "steel grade identification code" and "target thickness" as feedforward features to trigger nonlinear decoupling of the state machine. The system automatically matches and protects specific soft steels, executing a combination of boundary commands including speed reduction clamping, minimal gap locking, high lead rate interlocking, and interlocking auxiliary machine stabilization. For conventional steels, constraints are released to execute high-throughput acceleration. Simultaneously, dynamic length compensation (DLC) phase angle correction and physical wear integral life warning based on heavy-load conditions are used. This invention eradicates shearing defects from the physical level, breaks through the bottleneck of low-speed operation of the production line, and significantly improves the shearing accuracy and intelligent operation and maintenance level of the equipment.

Claims

1. A dynamic decoupling control method for hot continuous rolling mill flying shear based on feedforward, characterized in that: include: S1. Connect the data link between the process control level and the basic automation level, and send out the "steel grade identification code" and "intermediate billet target thickness" as a two-dimensional feedforward matrix; S2, the basic automation-level main control unit performs nonlinear state machine decoupling based on a two-dimensional feedforward matrix and state machine model, and automatically calculates the combined boundary commands of each electromechanical actuator, including target speed, lead rate, blade clearance and auxiliary tension state; S3. Multi-dimensional execution and collaborative control: This includes the flying shear main drive frequency converter that communicates with the basic automation level, the shear blade gap adjustment, and the external auxiliary unit hot roll box pinch roller control. Each actuator receives decoupling commands issued by the state machine model at the moment of engagement and implements collaborative actions.

2. The dynamic decoupling control method for hot continuous rolling mill flying shear based on feedforward as described in claim 1, characterized in that: The state machine model receives two-dimensional feedforward features and performs nonlinear shunting matching and dynamic parameter decoupling on the current shearing condition in real time based on preset material rheological criteria.

3. The dynamic decoupling control method for hot continuous rolling mill flying shear based on feedforward as described in claim 2, characterized in that: The specific content of the nonlinear shunt matching and dynamic parameter decoupling includes: When identified as soft steel with specific low deformation resistance and a thickness ≥38mm, the system executes a combined electromechanical and rigid protection chamber command, including: Set a speed clamp to forcibly lock the main motor's target speed to a stable operating baseline; The CNC command clearance adjustment mechanism precisely locks the horizontal backlash of the cutting tool to the minimum limit value by adjusting the minimum clearance. The interlocking auxiliary machine presses down and simultaneously sends a cross-regional interlocking command to the hot coil box. During the shearing transient command, the pinch rolls quickly drop down and press down on the strip. The posture is stabilized by applying auxiliary calming tension to the rear of the strip. Combined with a high lead rate, the defects at the beginning and end of the soft steel strip are completely eliminated from the physical mechanism. When the feature vector does not meet the above specific conditions, the system terminates the above physical constraints and speeds up operation.

4. The dynamic decoupling control method for hot continuous rolling mill flying shear based on feedforward as described in claim 1, characterized in that: Regardless of the path chosen, the calculated target speed command must enter the dynamic length compensation integrator before being issued. This integrator continuously integrates the large inertial response lag of the heavy machinery transmission chain caused by speed change, corrects the initial phase in real time, and ensures the accuracy of the tangent point positioning.

5. The dynamic decoupling control method for hot continuous rolling mill flying shear based on feedforward as described in claim 1, characterized in that: An independent equivalent wear integral calculation model is established. Based on the feedforward steel grade and cross-sectional area, the highest wear weight factor is assigned to the most destructive extreme heavy load conditions. The single shear equivalent is accumulated at high frequency, and a rigid blade replacement early warning interlock is triggered when the physical fatigue critical threshold is reached.

Images