A method and system for controlling blade speed of flying shears

Abstract

The present invention relates to a flying shear blade speed control method and system, the method comprising the following steps: setting the speed V according to the current point in the shearing process of the shear blade; r Calculate the current point setting position during the shearing process, calculate the deviation between the setting position and the actual position, and then use the deviation between the setting position and the actual position to correct the current point theoretical setting speed to obtain the final setting speed V of the current point during the shearing process. set The solution of the present invention ensures the accuracy of the actual speed and the accuracy and stability of the flying shear shearing.

Description

Technical Field

[0001] The invention belongs to the technical field of plate processing, and in particular relates to a method and system for controlling the speed of a flying shear blade. Background Art

[0002] The metal plate cross-cutting unit has the function of efficient cut-to-length shearing. It can unwind, straighten and cut various coiled plate materials into plates of different specifications. It can be widely used in containers, machinery manufacturing, household appliances, automobiles, stainless steel products, light industry and other fields. It is an essential and efficient processing line in the plate processing industry.

[0003] As market requirements continue to rise, this field is in urgent need of technical solutions to improve the control accuracy of flying shears. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a method and system for controlling the blade speed of a flying shear. The speed control accuracy of the flying shear can be improved by adopting the present invention.

[0005] The technical solution of the present invention is implemented as follows: The present invention discloses a method for controlling the blade speed of a flying shear, comprising the following steps:

[0006] The speed V is theoretically set according to the current point in the shearing process of the shear blade r Calculate the current point setting position during the shearing process, calculate the deviation between the setting position and the actual position, and then use the deviation between the setting position and the actual position to correct the current point theoretical setting speed to obtain the final setting speed V of the current point during the shearing process. set .

[0007] Furthermore, the speed V is theoretically set according to the current point in the shearing process. r Calculate the current point setting position of the shear blade during the shearing process, including: using the shear blade theory to set the speed V r The displacement Y(t) of the shear blade is obtained by integrating the time, and the displacement Y(t) of the shear blade is converted into the setting angle of the shear blade.

[0008] Furthermore, the formula for converting the displacement of the shear blade Y(t) into the setting angle of the shear blade is: θ set (t) = (Y(t) / πD)%1.0*360.0, where D is the shear blade rotation diameter, π is the circumference, θ set The setting angle of the shear blade.

[0009] Furthermore, the deviation between the set position and the actual position is used to correct the theoretical set speed of the current point, and the final set speed V of the current point during the shearing process is obtained. setSpecifically, the shear blade position deviation e(t) is obtained by subtracting the set angle of the shear blade from the actual angle of the shear blade. According to the formula V set =V r +K P e(t)+K i ∫e(t)d(t) is used to calculate the final set speed V at the current point in the shearing process set , in the formula, V r K is the theoretical setting speed of the current point in the shearing process, P is the proportionality coefficient, K i is the integration coefficient.

[0010] The present invention discloses a shear blade speed control system for a flying shear, comprising a controller, a motor and a shear blade position detection sensor. The shear blade position detection sensor is used to detect the shear blade position in real time and transmit the detected shear blade position to the controller. The controller is used to output a control signal to control the motor to drive the shear blade to move. A program is provided in the controller. When the controller executes the program, the steps of the shear blade speed control method for the flying shear are implemented as described above.

[0011] Furthermore, the shear blade position detection sensor adopts an absolute encoder.

[0012] Furthermore, the motor is a vector motor.

[0013] Furthermore, the controller is connected to a frequency converter, the frequency converter is connected to a motor, and the controller is used to output a control signal to the frequency converter, so as to control the motor through the frequency converter.

[0014] Furthermore, the frequency converter is a vector frequency converter.

[0015] The present invention has at least the following beneficial effects: the present invention calculates the set position of the current point in the shearing process of the shear blade according to theory, and then uses the deviation between the set position and the actual position to correct the theoretical set speed of the current point to ensure the accuracy of the actual speed, thereby ensuring the accuracy and stability of the flying shear shearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A flow chart of a control method for a flying shear of a cross-cutting unit provided by an embodiment of the present invention;

[0018] Figure 2 A diagram of the motion trajectory of a shear blade provided in one embodiment of the present invention;

[0019] Figure 3 A typical configuration diagram of a flying shear device provided for one embodiment of the present invention;

[0020] Figure 4 A schematic diagram of a shear blade speed control system of a flying shear provided by an embodiment of the present invention;

[0021] Figure 5 Schematic diagram of a shear blade speed control curve provided by an embodiment of the present invention (the shear length L is less than the critical shear length L 0 );

[0022] Figure 6 A schematic diagram of a shear blade speed control curve provided by another embodiment of the present invention (the shear length L is greater than the critical shear length L 0 ). DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Taking the cross-cutting unit system as an example, the main work of the cross-cutting unit is to cut the head, straighten, cross-cut and stack the strips rolled by the cold rolling mill. The main equipment includes uncoiler, straightener, flying shear (such as swing shear), belt conveyor, stacking platform, etc. The flying shear is the key equipment. It can shear the moving strip with high precision according to the required fixed length while ensuring the synchronous coordination of the shear blade and other equipment in the machine train and the speed of the strip.

[0025] Process flow: coiling → uncoiling → feeding → straightening → shearing → belt output, the feed roller feeds the material forward, and the swing shear cuts the material according to the set length of the feed.

[0026] See also Figure 2 The motion of the shear blade is a circular motion. The present invention controls the shear blade to accelerate from the waiting position A to the uniform speed point B, and then starts to run at a uniform speed from the uniform speed point B to the steel throwing point C, runs at a uniform speed from the steel throwing point C to the deceleration point D, and decelerates from the deceleration point D to the waiting position A to complete one shearing. This cycle is repeated to achieve continuous fixed-length shearing of the strip.

[0027] Assume that the shear length of the strip is L, the current length of the strip is X, and the circumference of the circular motion of the shear blade is Y. 0 , the current displacement of the shear blade is Y, and the actual speed of the strip is VL , the shear blade rotation diameter is D, the radius is R, then the synchronous shearing length is πD, and the current point speed of the shear blade during the shearing process is V r , the theoretical setting speed of the current point during the shearing process is V ref , the final setting speed of the current point during the shearing process is V set , the time from the start of the shear blade to the current point is t, and the current actual angle of the shear blade is θ act , the setting angle of the shear blade is θ set The time it takes for the shear blade to accelerate from the waiting position to the uniform speed point is t 1 The distance from the waiting position to the uniform speed point is S. 1 The acceleration of the shear blade from the waiting position to the uniform speed point is a 1 The time from the uniform speed point to the steel throwing point is t 2 The distance from the uniform speed point to the throwing point is S. 2 The time it takes for the shear blade to decelerate from the deceleration point to the waiting position is t 3 The distance from the deceleration point to the waiting position of the shear blade is S 3 The acceleration of the shear blade from the deceleration point to the waiting position is a 3 The real-time displacement of the shear blade from the deceleration point to the waiting position is S Y , the maximum linear velocity of the shear blade is V rmax , the speed of the shear blade in the waiting position is V m , the waiting time of the shear blade in the waiting position is t m , the shearing interval is t b , the shear blade position deviation is e(t), and the feeding length deviation of the feed roller is x(t).

[0028] Embodiment 1

[0029] See also Figure 1 The embodiment of the present invention provides a method for controlling the blade speed of a flying shear, comprising the following steps:

[0030] The current setting position of the shear blade during the shearing process is calculated according to the theoretical setting speed of the current point in the shearing process, and the deviation between the setting position and the actual position is calculated. Then, the deviation between the setting position and the actual position is used to correct the theoretical setting speed of the current point to obtain the final setting speed of the current point in the shearing process.

[0031] Furthermore, the speed V is theoretically set according to the current point in the shearing process. r Calculate the current point setting position of the shear blade during the shearing process, including: using the shear blade theory to set the speed V r The displacement of the shear blade is obtained by integrating the time. The formula is: Y(t) = ∫V r d(t), V r It is the speed of the current point during the shearing process.

[0032] Furthermore, the displacement of the shear blade is converted into the setting angle of the shear blade. The formula for converting the displacement of the shear blade Y(t) into the setting angle of the shear blade is: θ set (t) = (Y(t) / πD)%1.0*360.0, where πD is the synchronous shear length, θ set The setting angle of the shear blade.

[0033] Furthermore, the deviation between the set position and the actual position is used to correct the theoretical set speed of the current point, and the final set speed V of the current point during the shearing process is obtained. set Specifically, the shear blade position deviation e(t) is obtained by subtracting the set angle of the shear blade from the actual angle of the shear blade. The formula is: e(t) = θ set (t)-θ act (t), θ set is the setting angle of the shear blade, e(t) is the shear blade position deviation, θ act is the current actual angle of the shear blade;

[0034] According to the formula V set =V r +K P e(t)+K i ∫e(t)d(t) is used to calculate the final set speed V at the current point in the shearing process set , in the formula, V r V is the theoretical setting speed of the current point in the shearing process, set K is the final set speed of the current point in the shearing process, P is the proportionality coefficient, K i is the integration coefficient, K P , K i Can be obtained through experiments.

[0035] During the shearing process, the shear blade speed is corrected according to the difference between the shear blade position deviation and the strip shear length deviation; the swing shear and feed roller use the advantages of the vector controller to ensure the accuracy of the actual speed, thereby ensuring the accuracy and stability of the flying shear shearing.

[0036] The present invention obtains the theoretical setting speed V of the current point in the shearing process according to the set shearing blade speed control curve. r . Get the final set speed V of the current point set You can also set the speed V according to the current point set The shear blade speed control curve is modified; and the motion state of the shear blade is controlled according to the modified shear blade speed control curve.

[0037] As a preferred embodiment, this embodiment designs a control method for different cutting length speeds, because different cutting lengths have different corresponding speed control curves, such as Figure 5 and Figure 6 Therefore, finding the critical shear length is the key.

[0038] Determine the shear blade speed control curve, including:

[0039] Calculate the critical shear length;

[0040] The shear length L of the strip is set to be equal to the critical shear length L 0 Make comparisons;

[0041] If the shear length L is equal to the critical shear length L 0 , then the waiting time of the shear blade in the waiting position is t m = 0 and the speed V of the shear blade in the waiting position m =0;

[0042] If the shear length L is less than the critical shear length L 0 , then the waiting time t of the shear blade in the waiting position m = 0 and the speed V of the shear blade in the waiting position m >0, such as Figure 5 As shown;

[0043] If the shear length L is greater than the critical shear length L 0 , then the waiting time of the shear blade in the waiting position is t m >0 and the speed V of the shear blade in the waiting position m =0, such as Figure 6 As shown;

[0044] According to the above steps, t m 、V m A corresponding shear blade speed control curve is generated, and the motion state of the shear blade is controlled according to the shear blade speed control curve.

[0045] The present invention designs different speed control curves according to different shearing lengths, which can improve the shear blade control accuracy and reduce the control error.

[0046] Furthermore, if the shear length L is less than or equal to the critical shear length L 0 , then the shear blade is divided into three regions in one shearing, namely the acceleration region, the uniform speed region, and the deceleration region;

[0047] If the shear length L is greater than the critical shear length L 0 , the shear blade is divided into three areas during one shearing, namely the acceleration area, the uniform speed area, the deceleration area, and the stop waiting area.

[0048] Furthermore, the critical shear length L 0 The calculation formula is: Critical shear length Among them, V L is the actual speed of the strip, D is the shear blade rotation diameter, π is the circumference, S 1 S is the distance the shear blade accelerates from the waiting position to the uniform speed point. 3 V is the distance the shear blade decelerates from the deceleration point to the waiting position. rmax is the maximum linear speed of the shear blade.

[0049] Assume that the waiting bit speed V m =0, then we have the following formula:

[0050]

[0051] a 1 t 1 =v rmax

[0052] a 3 t 3 =v rmax .

[0053] Assume that the waiting bit speed V m >0, then the formula is as follows:

[0054]

[0055]

[0056] V m +a 1 t 1 =v rmax

[0057] V m +a 3 t 3 =v rmax .

[0058] Furthermore, if the shear length L is less than the critical shear length L 0 , then the speed of the shear blade in the waiting position Among them, V L is the actual speed of the strip, D is the shear blade rotation diameter, π is the circumference, S 1 S is the distance the shear blade accelerates from the waiting position to the uniform speed point. 3 V is the distance the shear blade decelerates from the deceleration point to the waiting position. rmax is the maximum linear speed of the shear blade.

[0059] Furthermore, if the shear length L is less than the critical shear length L 0 , then t 1+t 3 =t b -t 2 , Among them, t 1 The time it takes for the shear blade to accelerate from the waiting position to the uniform speed point, t 3 is the time it takes for the shear blade to decelerate from the deceleration point to the waiting position, t 2 t is the time taken for the shear blade to move from the uniform speed point to the steel throwing point. b is the shearing interval time, D is the shear blade rotation diameter, π is the circumference, S 1 S is the distance the shear blade accelerates from the waiting position to the uniform speed point. 3 V is the distance the shear blade decelerates from the deceleration point to the waiting position. rmax is the maximum linear speed of the shear blade;

[0060] Cutting interval time t b for: Where L is the shear length set for the strip, V L is the actual speed of the strip.

[0061] Furthermore, if the shear length L is greater than the critical shear length L 0 , then the waiting time of the shear blade in the waiting position is Among them, V L is the actual speed of the strip, S 1 S is the distance the shear blade accelerates from the waiting position to the uniform speed point. 3 V is the distance the shear blade decelerates from the deceleration point to the waiting position. rmax is the maximum linear speed of the shear blade.

[0062] Embodiment 2

[0063] See also Figure 3 and Figure 4 The embodiment of the present invention discloses a shear blade speed control system of a flying shear, including a controller, a motor and a shear blade position detection sensor. The shear blade position detection sensor is used to detect the shear blade position in real time and transmit the detected shear blade position to the controller. The controller is used to output a control signal to control the motor to drive the shear blade to move. A program is provided in the controller. When the controller executes the program, the steps of the shear blade speed control method of the flying shear are implemented as described in Example 1.

[0064] Furthermore, the shear blade position detection sensor adopts an absolute encoder.

[0065] Furthermore, the motor is a vector motor.

[0066] Furthermore, the controller is connected to a frequency converter, the frequency converter is connected to a motor, and the controller is used to output a control signal to the frequency converter, so as to control the motor through the frequency converter.

[0067] Furthermore, the frequency converter is a vector frequency converter (vector controller).

[0068] The invention enables the system to use a vector frequency converter and a common vector motor to drive the flying shear, which can ensure control accuracy and effect and effectively reduce the cost of the equipment. The invention is extremely stable in operation through feedback from the units that have been put into production.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling the blade speed of a flying shear, characterized in that: The steps include: Determine the shear blade speed control curve, including: Calculate the critical shear length; Compare the set shear length L of the strip with the critical shear length L0; If the shear length L is equal to the critical shear length L0, the waiting time t of the shear blade in the waiting position is m = 0 and the speed V of the shear blade in the waiting position m =0; If the shear length L is less than the critical shear length L0, the waiting time t of the shear blade in the waiting position is m = 0 and the speed V of the shear blade in the waiting position m >0; If the shear length L is less than the critical shear length L0, the speed of the shear blade in the waiting position Among them, V L is the actual speed of the strip, D is the rotation diameter of the shear blade, π is the circumference, S1 is the distance from the shear blade accelerating from the waiting position to the uniform speed point, S3 is the distance from the shear blade decelerating from the deceleration point to the waiting position, V rmax is the maximum linear speed of the shear blade; If the shear length L is greater than the critical shear length L0, the waiting time t of the shear blade in the waiting position is m >0 and the speed V of the shear blade in the waiting position m =0; If the cutting length L is greater than the critical cutting length L0, the waiting time of the cutting blade in the waiting position is Among them, V L is the actual speed of the strip, S1 is the distance from the waiting position to the uniform speed point, S3 is the distance from the deceleration point to the waiting position, V rmax is the maximum linear speed of the shear blade; According to the above steps, t m 、v m Generate the corresponding shear blade speed control curve; According to the set shear blade speed control curve, the theoretical set speed V at the current point in the shearing process is obtained. r ; The setting position of the current point in the shearing process is calculated according to the theoretical setting speed of the current point in the shearing process, the deviation between the setting position and the actual position is calculated, and then the deviation between the setting position and the actual position is used to correct the theoretical setting speed of the current point to obtain the final setting speed of the current point in the shearing process; Finally set the speed V according to the current point set The shear blade speed control curve is modified; and the motion state of the shear blade is controlled according to the modified shear blade speed control curve.

2. The method for controlling the blade speed of a flying shear according to claim 1, characterized in that: The current setting position of the shear blade during the shearing process is calculated according to the theoretical setting speed of the current point during the shearing process, specifically including: using the theoretical setting speed of the shear blade to integrate time to obtain the displacement Y(t) of the shear blade, and converting the displacement Y(t) of the shear blade to obtain the setting angle of the shear blade.

3. The method for controlling the blade speed of a flying shear according to claim 2, characterized in that: The formula for converting the displacement of the shear blade Y(t) into the setting angle of the shear blade is: θ set (t) = (Y(t) / πD)%1.0*360.0, where D is the shear blade rotation diameter, π is the circumference, θ set The setting angle of the shear blade.

4. The method for controlling the blade speed of a flying shear according to claim 1, characterized in that: The deviation between the set position and the actual position is used to correct the theoretical set speed of the current point to obtain the final set speed of the current point during the shearing process. Specifically, the shear blade position deviation e(t) is obtained by subtracting the set angle of the shear blade from the actual angle of the shear blade. According to the formula V set =V r +K P e(t)+K i ∫e(t)d(t) is used to calculate the final set speed V at the current point in the shearing process set , in the formula, V r K is the theoretical setting speed of the current point in the shearing process, P is the proportionality coefficient, K i is the integration coefficient.

5. A shear blade speed control system for a flying shear, characterized in that: The method comprises a controller, a motor and a shear blade position detection sensor, wherein the shear blade position detection sensor is used to detect the shear blade position in real time and transmit the detected shear blade position to the controller, and the controller is used to output a control signal to control the motor to drive the shear blade to move. The controller is provided with a program, and when the controller executes the program, the steps of the shear blade speed control method of the flying shear are implemented as described in any one of claims 1 to 4.

6. The shear blade speed control system of the flying shear according to claim 5, characterized in that: The shear blade position detection sensor adopts an absolute encoder.

7. The shear blade speed control system of the flying shear according to claim 5, characterized in that: The motor is a vector motor.

8. The shear blade speed control system of the flying shear according to claim 5, characterized in that: The controller is connected to the frequency converter, the frequency converter is connected to the motor, and the controller is used to output a control signal to the frequency converter, so as to control the motor through the frequency converter.

9. The shear blade speed control system of the flying shear according to claim 8, characterized in that: The inverter is a vector inverter.

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