Control method for a cutting mechanism

Abstract

The application provides a control method of a cutting mechanism, which comprises: calculating the relationship between a connecting rod servo angle and the displacement of a cutter in a feeding direction; calculating the relationship between a synchronous spindle angle and a workpiece feeding length according to a cutting length; determining the relationship between the synchronous spindle angle and the connecting rod servo angle according to the above two relationships; outputting a cam curve of the cutter; and controlling the movement of a motor according to the cam curve of the cutter to complete the whole cutting process, wherein the first speed component of the cutter in the feeding direction of the workpiece is always kept consistent with the feeding speed of the workpiece in the whole cutting process. The control method is suitable for driving the cutting device to cut thick workpieces.

Description

Technical Field

[0001] This invention relates to a control method for a cutting mechanism suitable for cutting thicker workpieces. Background Technology

[0002] Currently, common cutting methods include rotary cutting and flying shear.

[0003] Rotary cutting refers to a cutting blade fixed on a cutting roller, which rotates to cut the material. Because rotary cutting blades have a consistent angular velocity but different linear velocities at different diameters, this type of blade cannot cut thicker materials. When cutting thicker materials, the material exerts a significant lateral force on the blade, which can easily damage the blade and deform the cut edge, affecting product quality.

[0004] Flying shears involve accelerating the cutting component to the same linear velocity as the material before cutting, and then quickly returning to the starting point. Because the linear velocity is synchronized during cutting, flying shears can cut thicker materials, but this requires an additional cutting blade movement mechanism. This mechanism has a complex and bulky mechanical structure, occupying a large area. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention proposes a control method for a cutting mechanism. This control method allows the cutting mechanism to cut thicker workpieces without requiring an additional, mechanically complex cutter movement mechanism.

[0006] Specifically, this invention proposes a control method for a cutting mechanism, the cutting mechanism including a first link, a second link, a third link, and a cutter, wherein the first link and the second link are parallel to each other and driven by a servo motor, the third link is disposed between the first link and the second link, and the cutter is disposed on the third link and forms an angle with the third link in the length direction. The control method includes:

[0007] Calculate the relationship between the linkage servo angle and the displacement of the cutter in the feeding direction;

[0008] Calculate the relationship between the synchronous spindle angle and the workpiece feed length based on the cutting length;

[0009] Based on the aforementioned two sets of relationships, determine the relationship between the synchronous spindle angle and the connecting rod servo angle;

[0010] The output cutter's cam curve, and

[0011] The movement of the motor is controlled according to the cam curve of the cutter to complete the entire cutting process.

[0012] During the entire cutting process, the first velocity component of the cutter along the feeding direction of the workpiece is always kept consistent with the feeding speed of the workpiece.

[0013] According to an embodiment of the present invention, in the control method described above, during the cutting process, the first link and the second link swing in parallel, driving the cutter on the third link to perform reciprocating motion.

[0014] When the cutter performs reciprocating motion, the cutter is in a state perpendicular to the feeding direction of the workpiece being cut, and the cutter has a first velocity component along the feeding direction of the workpiece and a second velocity component perpendicular to the first velocity component.

[0015] According to an embodiment of the present invention, in the above control method, the relationship between the calculated linkage servo angle and the displacement of the cutter in the feeding direction is as follows:

[0016]

[0017] Wherein, △L is the displacement of the cutter in the feeding direction, △y is the servo angle of the connecting rod, R is the length of the first and / or second connecting rod, α is the angle of the motor connecting rod, and β is the horizontal deflection angle of the cutter shaft.

[0018] According to an embodiment of the present invention, in the above-described control method, when the workpiece feed length is equal to the displacement of the cutter in the feed direction, the relationship between the synchronous spindle angle and the workpiece feed length is expressed as follows:

[0019]

[0020] Wherein, △L is the displacement of the cutter in the feeding direction, △x is the angle of the synchronous spindle, and CL is the cutting length.

[0021] According to an embodiment of the present invention, in the above control method, the relationship between the synchronous spindle angle and the linkage servo angle is as follows:

[0022]

[0023] According to an embodiment of the present invention, in the above-described control method, the step of outputting the cam curve of the cutter further includes:

[0024] Based on the relationship between the synchronous spindle angle and the linkage servo angle, the cam curve of the cutter is formed and output by interpolation.

[0025] According to an embodiment of the present invention, in the control method described above, during the entire cutting process, the motor first decelerates and then accelerates to ensure that the first velocity component of the cutter along the feeding direction of the workpiece is consistent with the feeding speed of the workpiece.

[0026] It should be understood that the above general description and the following detailed description of the invention are exemplary and illustrative, and are intended to provide further explanation of the invention as described in the claims. Attached Figure Description

[0027] The accompanying drawings are included to provide a further understanding of the invention. They are incorporated in and constitute a part of this application. The drawings illustrate embodiments of the invention and, together with this specification, serve to explain the principles of the invention.

[0028] In the attached image:

[0029] Figure 1 This is a front view of the cutting mechanism according to the present invention.

[0030] Figure 2 The top view of the cutting mechanism according to the present invention and the system architecture are shown.

[0031] Figure 3 The kinematic relationship of the cutting mechanism of the present invention is shown.

[0032] Figure 4 The changes in position, speed, and acceleration of the cutter cam curve according to one embodiment are shown.

[0033] Figure 5 A basic flowchart of the control method for the cutting mechanism is shown.

[0034] Explanation of reference numerals in the attached figures:

[0035] 10 First Link

[0036] 20 Second Link

[0037] 30 Third Link

[0038] 40 cutting blades

[0039] 11 First Rotary Joint

[0040] 12 First hinge pair

[0041] 21 Second Rotary Joint

[0042] 22 Second hinge pair

[0043] W workpiece

[0044] A. Feed direction

[0045] Motors 51 and 52

[0046] 61, 62 Motor drivers

[0047] 70 Motion Controller

[0048] 80 Human-Computer Interaction Systems Detailed Implementation

[0049] Embodiments of the invention will now be described in detail with reference to the accompanying drawings. Preferred embodiments of the invention will now be described in detail, examples of which are illustrated in the drawings. Wherever possible, the same reference numerals will be used in all the drawings to denote the same or similar parts. Furthermore, although the terminology used herein is selected from commonly known and used terminology, some terms mentioned in this specification may have been chosen by the applicant at his or her discretion, and their detailed meanings are explained in the relevant sections of the description herein. Moreover, the invention should be understood not only by the actual terms used, but also by the meaning implied by each term.

[0050] The basic principles and preferred embodiments of the invention will be discussed in more detail with reference to the accompanying drawings.

[0051] First refer to Figure 1 and Figure 2 The cutting mechanism of the present invention mainly includes: a first connecting rod 10, a second connecting rod 20, a third connecting rod 30, and a cutting blade 40.

[0052] One end of the first connecting rod 10 is connected to the first rotating joint 11, and the other end is connected to the first hinge joint 12.

[0053] One end of the second link 20 is connected to the second revolute joint 21, and the other end is connected to the second hinge joint 22. The first link 10 and the second link 20 are parallel to each other.

[0054] The two ends of the third link 30 are respectively connected to the first hinge pair 12 and the second hinge pair 22.

[0055] The cutter 40 is mounted on the third link 30 and forms an angle β with the third link 30 in the length direction.

[0056] According to the above structure, the first connecting rod 10 and the second connecting rod 20 can swing in parallel under the drive of the first rotating joint 11 and the second rotating joint 21, driving the cutter 40 on the third connecting rod 30 to perform reciprocating motion and cut the workpiece. This invention is particularly suitable for cutting workpieces of a certain thickness, such as cables.

[0057] According to the present invention, during cutting, the workpiece W moves along... Figure 2The cutting motion follows the feed direction indicated by arrow A. Simultaneously, the cutter 40 performs a reciprocating motion, positioned perpendicular to the feed direction A of the workpiece W being cut. During this reciprocating motion, the cutter 40 has a first velocity component along the feed direction A of the workpiece W and a second velocity component perpendicular to the first velocity component. Based on the control method discussed below, the first velocity component of the cutter 40 during the cutting process can be kept consistent with the workpiece's feed speed, meaning that the cutter 40 and the workpiece W can remain relatively fixed in the feed direction A during the cutting process. Therefore, the cutting mechanism of the present invention can achieve cutting operations on thicker workpieces.

[0058] like Figure 2 As shown, the cutting mechanism of the present invention further includes: motors 51 and 52 driving the first link 10 and the second link 20; motor drivers 61 and 62 controlling the motors 51 and 52; a motion controller 70; and a human-machine interface system 80. The motion controller 70 has an electronic cam function, such as a SIMOTION motion controller supporting high-level language programming, to allow convenient planning of motion curves using accurate and flexible electronic cam curve functions. The output of the motion controller 70 is connected to the control terminals of the motor drivers 61 and 62, and the input of the motion controller 70 is connected to the human-machine interface system 80. The motion controller 70 parses the control command stream received from the human-machine interface system 80 into running signals and sends them to the motor drivers 61 and 62, thereby realizing motion control of each axis of the motors 51 and 52.

[0059] Under the dynamic control of the motion controller 70, the first velocity component of the cutter 40 during the entire process of cutting the workpiece W is always kept consistent with the feeding speed of the workpiece W. The entire process of cutting the workpiece W is the movement of the cutter 40 from the cutting starting point where it contacts the workpiece W to the cutting exit point where it leaves the workpiece W.

[0060] The following combination Figure 3 , Figure 4 and Figure 5 Let's discuss in detail the control methods of the above-mentioned cutting mechanism.

[0061] exist Figure 3In the example of the cutting process shown, L1-1 and L2-1 represent the starting points of the first link 10 and the second link 20, respectively; L1-2 and L2-2 represent the midpoints of the cutting process; and L1-3 and L2-3 represent the exit points. Correspondingly, the three points 1, 2, and 3 on the third link 30 sequentially indicate the positions of the cutter 40 at the starting, midpoint, and exit points of the cutting process. The area above the dashed lines shows the position from the main view angle, while the area below the dashed lines shows the position from the corresponding top view angle.

[0062] from Figure 3 It can be seen that from the starting point of the cut to the exit point, the cutter has a displacement in the workpiece feeding direction, that is, there is the aforementioned first velocity component in the workpiece feeding direction. This first velocity component ensures that the linear velocity of the cutter and the workpiece are the same.

[0063] Go to Figure 5 , Figure 5 A basic flowchart of the control method for the cutting mechanism is shown. The control method for the cutting mechanism of the present invention mainly includes:

[0064] Step 501: Calculate the relationship between the linkage servo angle and the displacement of the cutter in the feeding direction;

[0065] Step 502: Calculate the relationship between the synchronous spindle angle and the workpiece feed length based on the cutting length;

[0066] Step 503: Based on the two sets of relationships mentioned above, determine the relationship between the synchronous spindle angle and the connecting rod servo angle;

[0067] Step 504: Output the cam curve of the cutter, and

[0068] Step 505: Control the motor's movement according to the cutter's cam curve to complete the entire cutting process.

[0069] Throughout the entire cutting process, the first velocity component of the cutter along the feed direction of the workpiece is always kept consistent with the feed speed of the workpiece.

[0070] As discussed above, during the entire cutting process, the first link 10 and the second link 20 swing in parallel, driving the cutter 40 on the third link 30 to perform reciprocating motion. When the cutter 40 performs reciprocating motion, the cutter 40 is in a state perpendicular to the feeding direction A of the workpiece W being cut, and the cutter 40 has a first velocity component along the feeding direction A of the workpiece W and a second velocity component perpendicular to the first velocity component.

[0071] According to one embodiment, in step 501 above, the relationship between the linkage servo angle Δy and the cutter displacement ΔL in the feeding direction is calculated as follows:

[0072]

[0073] Where ΔL is the displacement of the cutter in the feeding direction, Δy is the servo angle of the linkage, and R is the length of the first and / or second linkage (i.e., Figure 3 The radii of the two circles in the diagram), α is the angle of the motor connecting rod (i.e., Figure 3 The angle α shown is the horizontal deflection angle of the tool axis (i.e., β). Figure 3 Angle β (as shown).

[0074] In the motion control of the cutting mechanism, a cutting cycle is usually defined as 0° to 360°. Therefore, in step 502 above, when the workpiece feed length is equal to the displacement of the cutter in the feeding direction, the relationship between the synchronous spindle angle Δx and the workpiece feed length (equivalent to the displacement of the cutter in the feeding direction) ΔL is as follows:

[0075]

[0076] Where △L is the workpiece feed length (equivalent to the displacement of the cutter in the feed direction), △x is the synchronous spindle angle, and CL is the cutting length (i.e., the length the workpiece travels in one 360° rotation of the motor). During the cutting process, the cutter and the workpiece maintain the same linear velocity, so the distance traveled by the cutter is much smaller than this cutting length.

[0077] Furthermore, in step 503, the relationship between the synchronous spindle angle Δx and the linkage servo angle Δy is as follows:

[0078]

[0079] Furthermore, step 504 above can further include: based on the relationship between the synchronous spindle angle Δx and the linkage servo angle Δy, the cam curve of the cutter can be formed and output through interpolation, such as... Figure 4 As shown. Among them, Figure 4 Curves a, b, and c in the figure sequentially illustrate the position changes, velocity changes, and acceleration changes of the cutter cam curve according to one embodiment.

[0080] Unlike standard rotary cutting synchronous intervals that operate at a fixed speed, the cutting mechanism of this invention features a motor that first decelerates and then accelerates throughout the cutting process. This ensures that the first velocity component of the cutter along the workpiece's feeding direction is consistent with the workpiece's feeding speed. For example, the numbers 1, 2, and 3 in curve b mark the velocity values ​​at the start point, midpoint, and exit point of the cut, respectively. Figure 4As shown by curves a to c in the figure, this control method can change speed after the cutter contacts the workpiece being cut, without considering the speed before or after the cutting process. Furthermore, the cutter adjustment range preferably uses a fifth-order polynomial connection, which ensures uniform acceleration change throughout the entire adjustment range, avoids sudden changes in current torque, and reduces mechanical vibration.

[0081] In summary, through unique structural and control design, the cutting mechanism of this application, while possessing a similarly simple structure to traditional rotary cutting mechanisms, can cut thicker workpieces. Compared to traditional flying shear mechanisms, the cutting mechanism of this application eliminates the need for an additional cutter movement mechanism, thus improving cost and reliability. Furthermore, the motion controller of this application supports high-level language programming, and its accurate and flexible electronic cam curve function facilitates motion curve planning. Therefore, the technical solution of this application represents a new technological application in the field of metal shearing, and can address some technical pain points in existing cutting technologies.

[0082] It will be apparent to those skilled in the art that various modifications and variations can be made to the exemplary embodiments described above without departing from the spirit and scope of the invention. Therefore, it is intended that this invention cover modifications and variations falling within the scope of the appended claims and their equivalents.

Claims

1. A control method of a cutting mechanism, characterized by, The cutting mechanism comprises a first connecting rod, a second connecting rod, a third connecting rod and a cutter, wherein the first connecting rod and the second connecting rod are parallel to each other and are driven by a servo motor, the third connecting rod is arranged between the first connecting rod and the second connecting rod, the cutter is arranged on the third connecting rod and forms an inclination angle with the third connecting rod in the length direction, and the control method comprises: calculating the relationship between the connecting rod servo angle and the displacement of the cutter in the feeding direction of the workpiece; calculating the relationship between the synchronous spindle angle and the workpiece feeding length according to the cutting length; determining the relationship between the synchronous spindle angle and the connecting rod servo angle according to the above two groups of relationships; outputting the cam curve of the cutter, and controlling the movement of the motor according to the cam curve of the cutter to complete the entire cutting process, wherein, in the entire cutting process, the first speed component of the cutter in the feeding direction of the workpiece is always kept consistent with the feeding speed of the workpiece.

2. The control method according to claim 1, characterized by, In the cutting process, the first connecting rod and the second connecting rod swing in parallel to drive the cutter on the third connecting rod to perform reciprocating motion, wherein, in the reciprocating motion of the cutter, the cutter is perpendicular to the feeding direction of the workpiece to be cut, and the cutter has a first speed component in the feeding direction of the workpiece and a second speed component perpendicular to the first speed component.

3. The control method according to claim 1, characterized by, The calculation of the relationship between the connecting rod servo angle and the displacement of the cutter in the feeding direction of the workpiece is: wherein, △L is the displacement of the cutter in the feeding direction, △y is the connecting rod servo angle, R is the length of the first and / or second connecting rod, α is the motor connecting rod angle, and β is the horizontal deflection angle of the cutter shaft.

4. The control method according to claim 3, characterized by, In the case where the workpiece feeding length is equal to the displacement of the cutter in the feeding direction, the relationship between the synchronous spindle angle and the workpiece feeding length is represented as: wherein, △L is the displacement of the cutter in the feeding direction, △x is the synchronous spindle angle, and CL is the cutting length.

5. The control method according to claim 4, characterized by, The relationship between the synchronous spindle angle and the connecting rod servo angle is:

6. The control method according to claim 5, characterized by, The step of outputting the cam curve of the cutter further comprises: on the basis of the relationship between the synchronous spindle angle and the connecting rod servo angle, the cam curve of the cutter is formed and outputted by interpolation.

7. The control method according to claim 6, characterized by, In the entire cutting process, the motor first decelerates and then accelerates to ensure that the first speed component of the cutter in the feeding direction of the workpiece is consistent with the feeding speed of the workpiece.

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