Control method of shearing mechanism

Abstract

The present invention provides a control method for a shearing mechanism, which includes an electronic cam. The control method includes: providing a first number of points, and establishing a first straight line segment in a coordinate system through the first number of points; providing a second number of points, and establishing a first cam control curve in the coordinate system through the second number of points, wherein the first cam control curve includes a first curve segment and a second curve segment, and the vertical coordinates of the first curve segments are both 0; multiplying the first cam control curve by 1 and superimposing it with the first straight line segment to obtain a second cam control curve; the second cam control curve includes a third curve segment and a fourth curve segment, and translating the fourth curve segment of the second cam control curve along the horizontal axis of the coordinate system until the end point of the fourth curve segment coincides with the starting point of the third curve segment, to obtain a third cam control curve, thereby controlling the electronic cam. The technical solution of the present invention can make the machine operation smoother and the shearing more precise.

Description

Technical Field

[0001] The present invention relates to the field of control technology, and in particular to a control method for a shearing mechanism. Background Art

[0002] Tracking shearing is an important application of electronic cams. As the number of applications for tracking shearing increases, the requirements for the control methods of electronic cams in tracking shearing mechanisms are becoming increasingly higher.

[0003] The pull-back methods of the shearing mechanism in the industry can be divided into absolute position pull-back method and curve pull-back method.

[0004] In the absolute position pullback method, after the tracking action is completed, the absolute position pullback method is used to return to the origin. The disadvantage of this method is that the pullback speed is difficult to calculate. In the case of high spindle speed, the acceleration and deceleration commands of the S-curve (S-CURVE) in the absolute position method are planned by the bottom layer, making it difficult to accurately calculate the maximum speed of the tracking shear. If the tracking shear speed is calculated too high, it will pull back prematurely and wait for the next meshing cycle. This will make the action inconsistent and easily cause motor overload. If the tracking shear speed is calculated too low, it is easy to cause the mechanism to return to the origin before the next meshing cycle signal arrives, resulting in insufficient mechanism accuracy.

[0005] like Figure 1 What is shown is a schematic diagram of the shear speed curve when the absolute position pullback method is adopted. The part of the curve 101 with a positive speed above the horizontal axis is the outward stroke, and the part of the curve 102 with a negative speed below the horizontal axis is the return stroke. The outward stroke curve is established through the table building tool. The distance of the outward stroke is known, and the return stroke is executed using the absolute position instruction. The execution of the absolute position instruction requires specifying the acceleration, speed and deceleration. Regardless of whether the unit of acceleration and deceleration is ms or Pulse / s^2, it is difficult to accurately calculate the pullback speed so that the next meshing cycle arrives when the mechanism is pulled back to the origin. Here, when the unit of acceleration and deceleration is ms, the acceleration represents the time required to accelerate from 0 to 3000rpm, and the deceleration represents the time required to decelerate from 3000rpm to 0. Therefore, when the absolute position pullback method is adopted, the pullback generally selects the highest speed, that is, the pullback is carried out in advance to wait for the next meshing cycle. This will make the entire action less smooth and prone to overload.

[0006] In the curve pullback method, the electronic cam curve includes both the outbound and return portions, so the return speed also varies with the drive shaft speed. Currently, the curve pullback method is generally used in high-speed shearing applications. However, existing solutions for establishing the shear belt pullback curve all use two curves to form the shear belt pullback curve. That is, a forward curve is established, and then this curve is multiplied by -1 and added to the lead to form a return curve. The forward curve is then translated until the end point of the forward curve coincides with the starting point of the return curve to form a complete shear belt pullback curve. The disadvantage of this approach is that the instantaneous current fluctuation when the mechanism speed changes from positive to negative or from negative to positive is relatively large. When the drive shaft speed is high and the shear belt mechanism is heavy, the machine operation is unstable and easily causes overload.

[0007] like Figure 2 What is shown is a schematic diagram of the shearing speed curve when the curve pull-back method is adopted, and the upper and lower coordinate axes are cam curves. The curve pull-back method can circumvent the problem of difficulty in calculating the speed during pull-back, and the pull-back speed can change with the change of the active shaft speed. In the process of building the table, a forward curve is first established, and each point on this curve is multiplied by -1, and a lead curve is added to form a pull-back curve. This pull-back curve is spliced ​​behind the forward curve to form a cam control curve for pull-back of the shearing belt, namely the speed curve 201. The disadvantage of this approach is that when the shearing mechanism changes direction, that is, when the speed curve 201 changes from positive to negative or from negative to positive, the acceleration curve 203 corresponding to the speed curve 201 shows a sharp change in acceleration. The sharp change in acceleration means that the current of the servo motor changes sharply. The sharp change in the current of the servo motor will cause the machine to shake and the shearing mechanism to operate unstably.

[0008] The above two shearing control methods each have their own defects, so it is necessary to develop a new control scheme for the shearing mechanism.

[0009] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0010] The object of the present invention is to provide a control method for a shearing mechanism, thereby achieving accurate shearing in a relatively stable manner to a certain extent.

[0011] The present invention provides a control method for a tracking shearing mechanism, the tracking shearing mechanism including an electronic cam. The control method includes: providing a first number of points, and establishing a first straight line segment in a coordinate system using the first number of points, wherein the horizontal axis of the coordinate system represents the phase of an active shaft in the electronic cam; providing a second number of points, and establishing a first cam control curve in the coordinate system using the second number of points, wherein the first cam control curve includes a first curve segment and a second curve segment, the vertical coordinates of the first curve segments are both 0, and the phase intervals of the active shafts corresponding to the first straight line segment and the first cam control curve are the same; multiplying the first cam control curve by -1 and superimposing the resultant curve with the first straight line segment to obtain a second cam control curve, wherein the second cam control curve includes a third curve segment and a fourth curve segment; and translating the fourth curve segment of the second cam control curve along the horizontal axis of the coordinate system until the end point of the fourth curve segment coincides with the starting point of the third curve segment, thereby obtaining a third cam control curve for controlling the electronic cam.

[0012] In some embodiments, the ordinates of the first straight line segment, the first cam control curve, the second cam control curve, and the third cam control curve represent positions of the driven shaft in the electronic cam.

[0013] In some embodiments, the ordinate of the starting point of the first straight line segment is 0, and the ordinate of the first straight line segment increases linearly.

[0014] In some embodiments, the ordinates of the starting point and the end point of the second cam control curve are equal, and the ordinates of the starting point and the end point of the third cam control curve are equal.

[0015] In some embodiments, the fourth curve segment is a curve segment from the lowest point of the ordinate of the second cam control curve to an end point of the second cam control curve.

[0016] In some embodiments, the ordinates of the first straight line segment, the first cam control curve, the second cam control curve, and the third cam control curve represent the running speed of the driven shaft in the electronic cam.

[0017] In some embodiments, the vertical coordinate of the first straight line segment is constant and not 0.

[0018] In some embodiments, the first cam control curve is a parabola opening downward.

[0019] In some embodiments, the ordinates of the starting point and the end point of the first cam control curve and the ordinates of the starting point and the end point of the third cam control curve are both 0.

[0020] In some embodiments, the fourth curve segment is a curve segment from the lowest point of the ordinate of the position curve corresponding to the second cam control curve to the end of the position curve.

[0021] In some embodiments, the first number of points are uniformly arranged laterally.

[0022] In some embodiments, the second number of points are uniformly arranged laterally.

[0023] In some embodiments, after obtaining the third cam control curve, the control method further includes: obtaining a control curve of the servo motor of the electronic cam according to the third cam control curve, so as to control the outward and return strokes of the electronic cam through the servo motor.

[0024] In some embodiments, the acceleration curve of the electronic cam is obtained by the third cam control curve.

[0025] In some embodiments, the first curve segment of the first cam control curve is determined according to the running time required for the sheared material.

[0026] In a control method for a shearing mechanism provided by the present invention, a second cam control curve is obtained by multiplying a first cam control curve by -1 and superimposing the resultant curve with a first straight line segment, and a fourth curve segment of the second cam control curve is translated along the horizontal axis of the coordinate system until the end point of the fourth curve segment coincides with the starting point of the third curve segment, thereby obtaining a third cam control curve, i.e., a target control curve of an electronic cam. The acceleration of the target control curve of the electronic cam changes smoothly, which makes the current change of the servo motor smoother, the machine operation smoother, and the shearing more precise in high-speed shearing applications, thereby achieving smooth and precise control of the shearing mechanism.

[0027] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are incorporated into and constitute a part of this specification, illustrate embodiments consistent with the present invention, and together with the description, serve to explain the principles of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and it is clear that those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0029] Figure 1 The following schematic diagram shows the shear speed curve when the absolute position pullback method is adopted in the related art;

[0030] Figure 2The following schematic diagram shows the shear speed curve when the curve pull-back method is adopted in the related art;

[0031] Figure 3 A flow chart schematically illustrates a method for controlling a shearing mechanism in accordance with an embodiment of the present invention;

[0032] Figure 4 is a schematic diagram of a first straight line segment in an embodiment of the present invention;

[0033] Figure 5 is a schematic diagram of a second curve segment of a first cam control curve in an embodiment of the present invention;

[0034] Figure 6 A schematic diagram of a control curve obtained by multiplying the second curve segment of the first cam control curve by -1 and then splicing the first curve segment, or a schematic diagram of a control curve obtained by multiplying the first cam control curve by -1 in an embodiment of the present invention;

[0035] Figure 7 Schematic diagram of the second cam control curve in an embodiment of the present invention;

[0036] Figure 8 Schematic diagram of the third cam control curve in an embodiment of the present invention;

[0037] Figure 9 Schematic diagram of the speed curve and acceleration curve of the electronic cam finally generated in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art.

[0039] In addition, the described features, structures or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to achieve a full understanding of the embodiments of the present invention. However, it will be appreciated by those skilled in the art that the technical solutions of the present invention can be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. may be adopted. In other cases, known methods, devices, implementations or operations are not shown or described in detail to avoid blurring various aspects of the present invention.

[0040] In related technologies, a shearing mechanism reciprocates parallel to the object being sheared. The shearing process of a shearing mechanism can be divided into a synchronous zone and an asynchronous zone. Within the synchronous zone, the shearing mechanism and the object being sheared move at the same speed, thereby achieving shearing of the object. In the asynchronous zone, the shearing length can be varied by varying the speed within the asynchronous zone. The shearing process is a cyclical reciprocating motion. When the synchronous zone is large, the shearing mechanism can perform more complex shearing and punching operations.

[0041] In the shearing control method in the related art, there are problems such as unsmooth shearing action, overload and machine shaking.

[0042] To solve these problems, an embodiment of the present invention provides a control method for a shearing mechanism.

[0043] In an embodiment of the present invention, the shearing mechanism includes an electronic cam, which uses mathematical equations to plan the relative motion path of its active shaft and driven shaft, and can replace the original mechanical entity cam, and can break through the limitations of the shape of the entity mechanical cam. The electronic cam adopts master-slave control, and its control curve is a function curve and is established using a point drawing method similar to that in mathematics. The control curve of the electronic cam is a curve corresponding to the position of the master and slave axes, and is used to characterize the functional relationship between the master and slave axes. The control curve of the electronic cam can be a position, speed or acceleration curve, and its horizontal axis represents the phase of the active shaft in the electronic cam (or the position of the active shaft), and its vertical axis represents the position, speed or acceleration of the driven shaft in the electronic cam. The speed and acceleration can intuitively reflect the current change trend of the servo motor in the electronic cam, so that a preliminary judgment can be made on whether the mechanism is running smoothly.

[0044] like Figure 3 As shown, the control method of the shearing mechanism according to the embodiment of the present invention includes:

[0045] Step S302 : providing a first number of points, and establishing a first straight line segment in a coordinate system through the first number of points, wherein the horizontal axis of the coordinate system represents the phase of the driving axis in the electronic cam.

[0046] Step S304: Provide a second number of points, and establish a first cam control curve in the above coordinate system through the second number of points, wherein the first cam control curve includes a first curve segment and a second curve segment, the vertical coordinate of the first curve segment is 0, and the phase interval of the driving axis corresponding to the first straight line segment and the first cam control curve is the same.

[0047] Step S306 : multiply the first cam control curve by −1 and superimpose the resultant on the first straight line segment to obtain a second cam control curve. The second cam control curve includes a third curve segment and a fourth curve segment.

[0048] Step S308 : translating the fourth curve segment of the second cam control curve along the horizontal axis of the coordinate system until the end point of the fourth curve segment coincides with the starting point of the third curve, thereby obtaining a third cam control curve for controlling the electronic cam.

[0049] An embodiment of the present invention provides a control method for a shearing mechanism. In high-speed shearing applications, the control method can make the servo motor current of the shearing mechanism change more smoothly, the machine operation more stable, and the shearing more precise.

[0050] like Figure 4 The coordinate system shown is the coordinate system in step S302. The horizontal axis of the coordinate system represents the phase of the active shaft in the electronic cam (or the position of the active shaft), and the vertical axis of the coordinate system represents the running speed of the driven shaft in the electronic cam (as shown on the right vertical axis). Figure 4 As shown, a first number of points is provided, which can be, but is not limited to, 200. The 200 points are evenly arranged horizontally, and a speed straight line segment 401 (i.e., a first straight line segment) is established by the 200 points. The abscissa of the speed straight line segment 401 represents the phase of the active shaft in the electronic cam (or the position of the active shaft), and the ordinate of the speed straight line segment 401 represents the running speed of the driven shaft in the electronic cam (as shown on the right vertical axis). The speed straight line segment 401 is an electronic cam control curve established with the cutting length as the lead. At this time, the ordinate of the speed straight line segment 401 is constant and not 0, which is used to indicate that the driven shaft is running at a uniform speed.

[0051] Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 and Figure 8 The coordinate systems in the figure are all the same coordinate system. The horizontal axis of the coordinate system represents the phase of the active shaft in the electronic cam (or the position of the active shaft), and the vertical axis of the coordinate system represents the running speed of the driven shaft in the electronic cam (as shown on the right vertical axis).

[0052] exist Figure 4 Step S304 is executed in the coordinate system shown to provide a second number of points, which can be 200. These 200 points are evenly arranged horizontally, and a first speed pullback curve (i.e., a first cam control curve) is established using the 200 points. The first speed pullback curve includes a first curve segment and a second curve segment. The vertical coordinates of the first curve segments are both 0, and the phase intervals of the driving axes corresponding to the first speed pullback curve and the first straight line segment are the same, wherein the first curve segment of the first speed pullback curve is determined based on the running time required for the sheared material.

[0053] In some embodiments, the first speed pullback curve may be established in the following manner: Figure 5As shown, a third number of points is provided, which may be, but is not limited to, 180. These 180 points are evenly spaced laterally. A second curve segment 501 is established using these 180 points. The second curve segment 501 is a parabola that opens downward with the cutting length as the lead. The vertical coordinates of the start and end points of the second curve segment are both 0. A fourth number of points is provided, which may be, but is not limited to, 20. The vertical coordinates of these 20 points are always 0. These 20 points are evenly spaced laterally. The horizontal distances between each of the 20 points are equal to the horizontal distances between each of the 180 points. A first curve segment is established using these 20 points. The first curve segment is translated along the horizontal axis of the coordinate system until the end point of the first curve segment coincides with the start point of the second curve segment, forming a first velocity pullback curve (i.e., a first cam control curve). The first velocity pullback curve is a parabola that opens downward. The phase interval of the driving axis corresponding to the first velocity pullback curve is the same as the phase interval of the driving axis corresponding to the velocity straight line segment 401, and the vertical coordinates of the start and end points of the first velocity pullback curve are both 0.

[0054] like Figure 7 The third speed pullback curve 701 is shown as Figure 4 The points on the velocity straight line segment 401 shown and Figure 6 The corresponding points on the second speed pullback curve 601 are superimposed. Figure 6 The second velocity pullback curve 601 is shown. At this point, the phase intervals of the driving axis corresponding to the velocity straight segment 401, the second velocity pullback curve 601, and the third velocity pullback curve 701 are identical. This calculation process is equivalent to executing step S306 to obtain the third velocity pullback curve 701, i.e., the second cam control curve. The vertical coordinates of the starting and ending points of the third velocity pullback curve 701 are equal.

[0055] In some embodiments, the second speed pullback curve can also be established by multiplying all points on the second curve segment established by the above 180 points by -1 to obtain a fifth curve segment, and translating the first curve segment formed by the above 20 points along the horizontal axis of the coordinate system until the end point of the first curve segment coincides with the starting point of the fifth curve segment, which can also be obtained as follows: Figure 6 A second speed pullback curve 601 is shown.

[0056] The third velocity pullback curve 701 includes a third curve segment and a fourth curve segment. Specifically, the fourth curve segment is a curve segment within a specific phase interval of the third velocity pullback curve 701. This specific phase interval is determined based on the position curve of the shear mechanism derived from the third velocity pullback curve 702. Specifically, this specific phase interval is the phase interval between the lowest ordinate point on the shear mechanism position curve and the end point of the position curve. In some embodiments, the corresponding shear mechanism position curve can be obtained by integrating the points on the third velocity pullback curve 702.

[0057] Because the speed straight segment 401 and the second speed pull-back curve 601 are both established with the cutting length as the lead, all points on the first speed pull-back curve are multiplied by -1 and superimposed on the speed straight segment 401, which means that after the two are added together, the shearing mechanism can start from the original position and return to the original position.

[0058] See for example Figure 7 The third speed retraction curve 701 shown in FIG. 7 has a starting speed (vertical coordinate value) of not 0, which means that the operating speed of the shearing mechanism does not start from 0. Therefore, it cannot be directly applied in actual scenarios. At this time, step S308 is executed to translate the fourth curve on the third speed retraction curve 701 to the left along the horizontal axis of the above coordinate system until the end point of the fourth curve segment coincides with the starting point of the third curve segment, thus obtaining Figure 8 The fourth speed retraction curve 801 is the third cam control curve. The vertical coordinates of the starting and ending points of the third cam control curve are both 0, which means that the shearing mechanism starts to accelerate at a speed of 0 from the original position and returns to the original position at a speed of 0 after a certain period of time.

[0059] After executing step S308, the acceleration curve of the electronic cam can be obtained through the third cam control curve. Figure 9 The figure shows the speed curve of the electronic cam, namely the fourth speed pullback curve 801 and the acceleration curve 903. Figure 9 As shown, the acceleration of the shearing mechanism changes smoothly during normal operation and reversal, so that the machine operates stably without jitter problems. In some embodiments, the acceleration curve of the corresponding electronic cam can be obtained by performing a derivative operation on the fourth speed pullback curve 801.

[0060] After step S308 , a control curve of the servo motor of the electronic cam is obtained according to the third cam control curve, so as to control the forward and return strokes of the electronic cam through the servo motor.

[0061] In the above, the vertical axes of the speed straight line segment (first straight line segment), the first speed pullback curve (first cam control curve), the third speed pullback curve (second cam control curve) and the fourth speed pullback curve (third cam control curve) represent the running speed of the driven shaft in the electronic cam, that is, the speed straight line segment, the first speed pullback curve, the third speed pullback curve and the fourth speed pullback curve are all speed curves of the electronic cam.

[0062] In some embodiments, namely, Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 and Figure 8 The coordinate system mentioned above is another identical coordinate system. The horizontal axis of the coordinate system represents the phase of the active shaft in the electronic cam (or the position of the active shaft), and the vertical axis of the coordinate system represents the running position of the driven shaft in the electronic cam (as shown on the left vertical axis). The position curve of the electronic cam is established to accurately and stably control the electronic cam. Figure 4 The coordinate system shown is the coordinate system in step S302, providing a first number of points. The first number can be, but is not limited to, 200. These 200 points are evenly arranged horizontally. A position straight line segment 402 (i.e., a first straight line segment) is established by using these 200 points. The position straight line segment 402 is a linear cam curve established with the cutting length as the lead. At this time, the vertical coordinate of the starting point of the position straight line segment 402 is 0 and the vertical coordinate of the position straight line segment 402 increases linearly, indicating that the driven shaft is running at a uniform speed.

[0063] exist Figure 4 Step S304 is executed in the coordinate system shown to provide a second number of points. The second number can be but is not limited to 200. The 200 points are evenly arranged laterally, and a first position pullback curve (i.e., a first cam control curve) is established using the 200 points. The first position pullback curve includes a first curve segment and a second curve segment. The vertical coordinate of the first curve segment is 0, and the phase interval of the driving axis corresponding to the first position pullback curve and the first straight line segment 402 is the same, wherein the first curve segment of the first position pullback curve is determined according to the running time required for the sheared material.

[0064] In some embodiments, the first position pullback curve can be established by: Figure 5In the coordinate system shown, a third number of points is provided, which can be, but is not limited to, 180. These 180 points are uniformly spaced laterally, and a second curve segment 502 is established using these 180 points. The first curve segment 502 has a lead of the cutting length. A fourth number of points is provided, which can be, but is not limited to, 20. These 20 points are uniformly spaced laterally, and their vertical coordinates are always zero. A first curve segment is established using these 20 points. The first curve segment is translated along the horizontal axis of the coordinate system until the endpoint of the first curve segment coincides with the starting point of the second curve segment 502, forming a first position pullback curve (i.e., a first cam control curve). The first position pullback curve and the phase interval of the active axis corresponding to the position straight line segment 402 are the same.

[0065] like Figure 7 The third position pullback curve 702 is shown as Figure 4 The points on the position straight line segment 402 shown and Figure 6 The corresponding points on the second position pullback curve 602 are superimposed. Multiplying all points on the first position pullback curve by -1, we can get Figure 6 The second position pullback curve 602 is shown. At this point, the phase intervals of the driving axis corresponding to the position straight line segment 402, the second position pullback curve 602, and the third position pullback curve 702 are identical. The above calculation process is equivalent to executing step S306, obtaining the third position pullback curve 702, i.e., the second cam control curve. The vertical coordinates of the starting point and end point of the third position pullback curve 702 are equal.

[0066] In one embodiment, the second position pullback curve can also be established by multiplying all points on the second curve segment 502 established by the above 180 points by -1 to obtain a sixth curve segment, and translating the first curve segment formed by the above 20 points along the horizontal axis of the coordinate system until the end point of the first curve segment coincides with the starting point of the sixth curve segment, which can also be obtained as follows: Figure 6 A second position pullback curve 602 is shown.

[0067] See for example Figure 7The third position pullback curve 702 shown includes a third curve segment and a fourth curve segment. Specifically, the fourth curve segment is the curve segment from the lowest point of the vertical coordinate on the third position pullback curve 702 to the end point of the curve. The speed (vertical coordinate value) of the starting point of the third position pullback curve 702 is not 0, which means that the running speed of the shearing mechanism does not start from 0, so it cannot be directly applied in actual scenarios. In some embodiments, the speed curve of the corresponding shearing mechanism can be obtained by performing a derivative operation on the third position pullback curve. Since the running speed of the shearing mechanism does not start from 0, step S308 is executed to translate the fourth curve segment of the third position pullback curve 702 along the horizontal axis of the above-mentioned coordinate system until the end point of the fourth curve segment coincides with the starting point of the third curve segment, and the following is obtained. Figure 8 The fourth position pullback curve 802 is the third cam control curve. At this time, the electronic cam starts from zero, and the starting point and end point of the fourth position pullback curve 802 are the same point, that is, the electronic cam returns to the origin after running.

[0068] After step S308 is executed, the speed curve and the acceleration curve of the electronic cam can be obtained through the fourth position pullback curve 802 (ie, the third cam control curve). Figure 9 The acceleration curve 903 shown is calculated from the fourth-position pullback curve 802. This indicates that the shearing mechanism experiences steady acceleration changes during normal operation and reversal, ensuring stable machine operation without jitter. In some embodiments, the corresponding electronic cam velocity curve can be obtained by taking the derivative of the fourth-position pullback curve 802. The corresponding electronic cam acceleration curve can then be obtained by taking the derivative of the resulting velocity curve again.

[0069] After step S308 , a control curve of the servo motor of the electronic cam is obtained according to the third cam control curve, so as to control the forward and return strokes of the electronic cam through the servo motor.

[0070] In the above, the vertical axes of the position straight line segment (first straight line segment), the first position pullback curve (first cam control curve), the third position pullback curve (second cam control curve) and the fourth position pullback curve (third cam control curve) represent the running position of the driven shaft in the electronic cam, that is, the position straight line segment, the first position pullback curve, the third position pullback curve and the fourth position pullback curve are all position curves of the electronic cam.

[0071] In a specific implementation of the embodiment of the present invention, a control curve of the electronic cam can be established by using a table building tool. The specific process includes the following steps:

[0072] A first number of points is set using a table creation tool with the cutting length as the lead. The first number of points can be, but is not limited to, 200. The lateral distances between each of the 200 points are equal. A first straight line segment is established using the 200 points. The vertical coordinate of the first straight line segment represents the operating position of the driven shaft in the electronic cam.

[0073] Using a table creation tool, a third number of points is created using the cutting length as a guide. This third number can be, but is not limited to, 180. The lateral distances between each of these 180 points are equal to the lateral distances between each of the aforementioned 200 points. A forward curve is created using these 180 points. The ordinate of this forward curve also represents the operating position of the driven shaft in the electronic cam. In this embodiment, the cutting length is set to 1009000, but in actual applications, this is not limited to this.

[0074] The ordinate data of the 200 points in the first straight line segment are shown in Table 1 below:

[0075] Table 1 Data of the first straight line segment

[0076] 0 5045 10090 15135 20180 …… 988820 993865 998910 1003955 1009000

[0077] The ordinate data of the 180 points in the outbound curve are shown in Table 2 below:

[0078] Table 2 Outbound curve data

[0079] 0 8 32 80 160 …… 1008968 1008992 1009000 1009000 1009000

[0080] Multiply the 180 points shown in Table 2 by -1. To ensure that the phase intervals of the driving shaft corresponding to the first straight line segment and the forward curve are the same, multiply the 180 points by -1 and then add a fourth number of zeros in front. The fourth number can be, but is not limited to, 20. The horizontal distance between these 20 points is the same as the horizontal distance between the 180 points. The first cam control curve can be established using these 200 (20 + 180) points. The generated data is shown in Table 3 below:

[0081] Table 3 multiplied by -1 and supplemented with 0 data

[0082] 0 0 0 0 0 …… -1008968 -1008992 -1009000 -1009000 -1009000

[0083] The data of the 200 points shown in Table 3 can also be obtained by adding the aforementioned 20 zeros to the front of the 180 points shown in Table 2 and then multiplying by -1. The first cam control curve is established using these 200 points.

[0084] The 200 points on the first cam control curve shown in Table 3 and the 200 points on the first straight line segment shown in Table 1 are added together to generate the data shown in Table 4 below. The second cam control curve is established using this data:

[0085] Table 4 Added data

[0086] 0 5045 10090 15135 20180 …… -20148 -15127 -10090 -5045 0

[0087] Calculations show that the speed of the second cam control curve established using the 200 points shown in Table 4 does not start from zero. Therefore, in actual scenarios, this second cam control curve cannot be used directly to control the electronic cam. Therefore, all points between the lowest point and the last point of the position coordinates are moved to the front end of the 200 points. The third cam control curve, or the target cam control curve, is established using these 200 points. The data shown in Table 5 is finally obtained:

[0088] Table 5 Data after movement

[0089] -132291 -132131 -131811 -131330 -130689 …… -131330 -131811 -132131 -132209 -132291

[0090] The present invention further provides a control device for a shearing mechanism, which is used to execute the control method for the shearing mechanism in the above-mentioned embodiments.

[0091] The control method and device of the shearing mechanism provided by the present invention obtain a second cam control curve by multiplying the first cam control curve by -1 and superimposing it with the first straight line segment, and translate the fourth curve of the second cam control curve along the horizontal axis of the coordinate system until the end point of the fourth curve coincides with the starting point of the third curve segment, thereby obtaining a third cam control curve, i.e., the target control curve of the electronic cam. The acceleration of the target control curve of the electronic cam changes smoothly, which makes the current change of the servo motor more stable, the machine operation more stable, and the shearing more precise in high-speed shearing applications, thereby realizing smooth and precise control of the shearing mechanism.

[0092] Other embodiments of the present invention will readily occur to those skilled in the art after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

[0093] It will be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof.

Claims

1. A control method for a shearing mechanism, wherein the shearing mechanism comprises an electronic cam, characterized in that: The control method includes: Providing a first number of points, and establishing a first straight line segment in a coordinate system through the first number of points, wherein the horizontal axis of the coordinate system represents the phase of the driving shaft in the electronic cam; Providing a second number of points, and establishing a first cam control curve in the coordinate system using the second number of points, wherein the first cam control curve includes a first curve segment and a second curve segment, the ordinates of the first curve segments are both 0, and the first straight line segment and the first cam control curve have the same phase interval for the driving axis; multiplying the first cam control curve by -1 and superimposing the curve with the first straight line segment to obtain a second cam control curve, wherein the second cam control curve includes a third curve segment and a fourth curve segment; The fourth curve segment of the second cam control curve is translated along the horizontal axis of the coordinate system until the end point of the fourth curve segment coincides with the starting point of the third curve segment to obtain a third cam control curve for controlling the electronic cam.

2. The control method according to claim 1, characterized in that: The ordinates of the first straight line segment, the first cam control curve, the second cam control curve, and the third cam control curve represent positions of the driven shaft in the electronic cam.

3. The control method according to claim 2, characterized in that: The ordinate of the starting point of the first straight line segment is 0, and the ordinate of the first straight line segment increases linearly.

4. The control method according to claim 2, characterized in that: The ordinates of the starting point and the end point of the second cam control curve are equal, and the ordinates of the starting point and the end point of the third cam control curve are equal.

5. The control method according to claim 2, characterized in that: The fourth curve segment is a curve segment from the lowest point of the ordinate of the second cam control curve to the end point of the second cam control curve.

6. The control method according to claim 1, characterized in that: The ordinates of the first straight line segment, the first cam control curve, the second cam control curve, and the third cam control curve represent the running speed of the driven shaft in the electronic cam.

7. The control method according to claim 6, characterized in that: The vertical coordinate of the first straight line segment is constant and not 0.

8. The control method according to claim 6, characterized in that: The first cam control curve is a parabola opening downward.

9. The control method according to claim 6, characterized in that: The ordinates of the starting point and the end point of the first cam control curve and the ordinates of the starting point and the end point of the third cam control curve are both 0.

10. The control method according to claim 6, characterized in that: The fourth curve segment is a curve segment from the lowest point of the ordinate of the corresponding position curve on the second cam control curve to the end of the position curve.

11. The control method according to claim 1, characterized in that: The first number of points are evenly arranged in the transverse direction.

12. The control method according to claim 1, characterized in that: The second number of points are evenly arranged in the transverse direction.

13. The control method according to claim 1, characterized in that: After obtaining the third cam control curve, the control method further includes: obtaining a control curve of a servo motor of the electronic cam according to the third cam control curve, so as to control the outward and return strokes of the electronic cam through the servo motor.

14. The control method according to claim 2 or 6, characterized in that: The acceleration curve of the electronic cam is obtained through the third cam control curve.

15. The control method according to claim 1, characterized in that: The first curve segment of the first cam control curve is determined according to the running time required for the sheared material.

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