Small cutting device based on novel gantry structure

Abstract

The invention provides a small cutting device based on a novel gantry structure. The small cutting device comprises an X-direction linear module, a Z-direction linear module, a Y-direction linear module, a machine tool mounting bottom plate and a comprehensive control system. Miniaturization of the cutting device is achieved, the problems that high-speed operation is difficult to achieve due to the fact that a traditional cutting device is large in occupied area, low in production cost performance, large in movement inertia and the like when small workpieces are machined are solved, and meanwhile the vibration problem caused by the fact that the gravity center of a gantry is too high when the traditional cutting device operates at a high speed is solved. A Y-direction double-axis control system is designed through coordinate transformation decoupling, a contour error controller is constructed based on a model error and a dynamic error equation, the acceleration is controlled through the calculated error, a PID controller is used for adjusting a Y-direction linear module driving motor to output a signal to control the error, and the control precision is improved. Intelligent motion control over the Y-direction linear module is achieved, and the working stability and safety of the device are guaranteed.

Description

Technical Field

[0001] The invention belongs to the field of industrial manufacturing, and in particular relates to a small cutting device based on a new gantry structure. Background Art

[0002] The advancement of computers and modern design technology has given rise to CNC machining technology, which has greatly improved the production capacity of the manufacturing industry. Faced with the manufacturing industry's growing demand for production capacity, the application field of CNC cutting devices is constantly expanding. However, in the processing of small and micro parts, traditional large CNC cutting devices have exposed their limitations, including energy waste, large space occupation, high cost and low efficiency. Small cutting devices, with the advantages of lower cost, higher space efficiency and reduced inertia of moving parts, show the potential for high-speed and high-precision motion control, and become an innovative choice for small parts manufacturing. However, the spindle speed of existing small cutting devices on the market is often relatively fixed and the adjustment range is small, which limits its flexibility when processing different types of materials, especially when high speed is required for fine processing, which may not meet the needs. In addition, many small cutting devices still rely on manual operation and have a relatively low degree of automation, which makes their production efficiency low and there is a risk of human error. In view of the above problems, it is urgent to develop a new type of small high-speed CNC cutting device to solve the above drawbacks in the current manufacturing industry. Summary of the invention

[0003] In view of the problems existing in the prior art of using traditional cutting devices in the current manufacturing industry when processing small workpieces, such as large footprint, low production cost-effectiveness, and low degree of automation, the present invention provides a small cutting device based on a new gantry structure to solve the above problems.

[0004] The present invention achieves the above technical objectives through the following technical means.

[0005] A small cutting device based on a new gantry structure comprises an X-direction linear module, a Z-direction linear module, a Y-direction linear module A, a Y-direction linear module B, a machine tool mounting base plate and a control system for comprehensively controlling the operation of a milling machine; the X-direction linear module, the Y-direction linear module A and the Y-direction linear module B have the same structural composition, wherein the Y-direction linear module A and the Y-direction linear module B are symmetrically arranged on the machine tool mounting base plate; the X-direction linear module is installed between the Y-direction linear module A and the Y-direction linear module B, and the Z-direction linear module is installed on the X-direction linear module.

[0006] Furthermore, the X-direction linear module includes an X-direction linear module mounting base plate, and the two ends of the X-direction linear module mounting base plate are respectively fixed with a motor mounting plate and a screw mounting plate by bolts, a driving motor is mounted on the motor mounting plate, a power output end of the driving motor is connected to the screw by a coupling, the other end of the screw is mounted on the screw mounting plate, and the coupling connects the driving motor and the screw; two guide rails are installed between the motor mounting plate and the screw mounting plate by bolts, the slide is slidably installed on the guide rails and cooperates with the screw thread; a connecting plate is installed on the slide by bolts, which is used to realize the connection of the slide with the Z-direction linear module through the connecting plate; the X-direction linear module mounting base plate is fixed to the connecting plates of the Y-direction linear module A and the Y-direction linear module B by bolts and L-shaped connecting blocks.

[0007] Furthermore, the Z-direction linear module also includes a drive motor, a motor mounting plate, a coupling, a slide, a guide rail, a screw rod, a connecting plate, and a Z-direction linear module mounting base plate, and the mounting method between the components is the same as that of the X-direction linear module; the Z-direction linear module also includes an electric spindle fixing block;

[0008] In the Z-direction linear module, the connecting plate is fixed to the slide by bolts, and is used to connect with the electric spindle fixing block to drive it to move along the Z direction; the Z-direction linear module mounting base plate is fixed to the connecting plate of the X-direction linear module by bolts, and the fixed position is two-thirds of the distance from the drive motor of the Z-direction linear module.

[0009] Furthermore, the control system designs a dual-axis control system in the Y direction through coordinate transformation decoupling to realize motion control of the Y-direction linear module A and the Y-direction linear module B, thereby preventing the gantry from shifting, as follows:

[0010] The mechanical motion equation of a permanent magnet synchronous motor is:

[0011]

[0012] Where M is the rotor mass, K is f is the thrust coefficient, C is the friction coefficient, F is the load impedance, i q is the stator current, is the rotor acceleration, is the rotor speed;

[0013] Let i q is the input, v is the output, then the transfer function of the object model is:

[0014]

[0015] The simplified dynamic model of the dual-axis motion system is:

[0016]

[0017] in, and They are the accelerations of the Y-direction linear module A and the Y-direction linear module B, and are the speeds of linear module A in the Y direction and linear module B in the Y direction, u y1 and u y2 They are the control inputs of the Y-direction linear module A and the Y-direction linear module B respectively;

[0018] The position error is defined as the distance e between the expected position EP and the actual position AP, expressed as:

[0019] e=||AP-EP||

[0020] According to the two-dimensional coordinate transformation matrix:

[0021]

[0022] Among them, e y1 and e y2 are the motion errors of the slides on the Y-direction linear module A and the Y-direction linear module B respectively; e t is the tangential error, e c is the contour error, θ is the rotation angle between the actual coordinate system and the reference coordinate system;

[0023] Based on the dynamic model and error decomposition of the dual-axis system, the dynamic error equation is established:

[0024]

[0025] Among them, f y1 and f y2 is the dynamic model of the system in the y1-axis and y2-axis directions, C y1 and C y2 is the friction factor, K y1 and K y2 is the gain factor, and They are the speed errors of the Y-direction linear module A and the Y-direction linear module B during their motions;

[0026] The dynamic error equation further describes the change of system error over time, and the error in each direction can be controlled independently. Based on the model error and the dynamic error equation, a contour error controller is constructed to ensure the accuracy and stability of the system:

[0027]

[0028] Among them, K dis the differential gain of the contour error, K i is the integral gain of the contour error, K c is the proportional gain of the contour error; is the speed error in the direction of the contour error; e c is the contour error; the above calculated and e y1 and e y2 Substitute and e c The corresponding error control acceleration is obtained In actual control, The numerical value uses a PID controller to adjust the Y-direction linear module drive motor output signal to control the error.

[0029] The present invention has the following beneficial effects:

[0030] The present invention realizes the miniaturization of the cutting device, avoiding the problems caused by the use of traditional cutting devices when processing small workpieces, such as large footprint, low production cost performance, and difficulty in achieving high-speed operation due to the large motion inertia of the traditional cutting device; at the same time, since the gantry design of the present invention is relatively low, the vibration problem caused by the high center of gravity of the gantry when the traditional cutting device is running at high speed is solved; in addition, the present invention also realizes intelligent motion control of the Y-direction linear module through coordinate transformation decoupling design of the dual-axis control system in the Y direction, thereby preventing the gantry from offsetting and ensuring the stability and safety of the cutting device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0032] Figure 2 It is a schematic diagram of the structure of the linear module in the X direction of the present invention;

[0033] Figure 3 It is a schematic diagram of the structure of the linear module in the Z direction of the present invention;

[0034] Figure 4 It is a side view structural schematic diagram of the present invention;

[0035] Figure 5 It is a schematic diagram of the structure of the slide and the connecting plate of the present invention;

[0036] In the figure: 1, X-direction linear module; 2, Z-direction linear module; 3, Y-direction linear module A; 4, Y-direction linear module B; 5, machine tool installation base plate; 21, drive motor; 22, motor installation plate; 23, coupling; 24, slide; 25, guide rail; 26, lead screw; 31, electric spindle fixing block; 41, L-shaped connection block. 51- connection plate. DETAILED DESCRIPTION

[0037] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0038] like Figure 1 As shown, the small cutting device based on the new gantry structure of the present invention includes an X-direction linear module 1, a Z-direction linear module 2, a Y-direction linear module A3, a Y-direction linear module B4, a machine tool mounting base plate 5 and a control system for comprehensively controlling the operation of the milling machine.

[0039] like Figure 1 As shown, the X-direction linear module 1, the Y-direction linear module A3, and the Y-direction linear module B4 have the same structure, wherein the Y-direction linear module A3 and the Y-direction linear module B4 are symmetrically arranged on the machine tool mounting base plate 5, and are specifically fixed on the machine tool mounting base plate 5 by bolt connection. In this embodiment, the structure and working principle of the X-direction linear module 1 are described as an example, and the implementation methods of the Y-direction linear module A3 and the Y-direction linear module B4 are also the same, which will not be repeated. The X-direction linear module 1 is installed between the Y-direction linear module A3 and the Y-direction linear module B4, and the Z-direction linear module 2 is installed on the X-direction linear module 1.

[0040] like Figure 1 , 2 As shown in Figures 5 and 6, the X-direction linear module 1 includes a drive motor 21, a motor mounting plate 22, a coupling 23, a slide 24, a guide rail 25, a screw 26, a connecting plate 51, and an X-direction linear module mounting base plate 27. The motor mounting plate 22 and the screw mounting plate are respectively fixed at both ends of the X-direction linear module mounting base plate 27 by bolts. The drive motor 21 is mounted on the motor mounting plate 22. The power output end of the drive motor 21 is connected to the screw 26 through the coupling 23. The other end of the screw 26 is mounted on the screw mounting plate. The coupling 23 connects the drive motor 21 and the screw 26 so that the screw 26 can rotate with the drive motor 21. Two guide rails 25 are installed between the motor mounting plate 22 and the screw mounting plate by bolts. The slide 24 is slidably mounted on the guide rail 25 and is threadedly matched with the screw 26. When the screw 26 rotates, the slide 24 can move on the X stroke. The connecting plate 51 is fixed to the slide 24 by bolts, so that the slide 24 is connected to the Z-direction linear module 2 through the connecting plate 51, thereby driving the Z-direction linear module 2 to move along the X direction. Figure 1 , 2 As shown in FIG. 4 , the X-direction linear module mounting base plate 27 is fixed to the connecting plate 51 of the Y-direction linear module A3 and the Y-direction linear module B4 by bolts and L-shaped connecting blocks 41. The X-direction linear module 1 acts as a gantry structure in the cutting device.

[0041] like Figure 1 , 3 As shown in Figure 5, the Z-direction linear module 2 also includes a drive motor 21, a motor mounting plate 22, a coupling 23, a slide 24, a guide rail 25, a screw 26, a connecting plate 51, and also includes an electric spindle fixing block 31 and a Z-direction linear module mounting base plate. In the Z-direction linear module 2, the drive motor 21 drives the screw by connecting with the coupling 23, thereby further driving the slide 24 to slide; the motor mounting plate 22 is fixed to the Z-direction linear module mounting base plate by bolt connection; the coupling 23 connects the drive motor 21 and the screw 26, so that the screw 26 rotates with the drive motor 21; the slide 24 ensures movement in the Z stroke by cooperating with the guide rail 25 and the screw 26; the guide rail 25 is fixed to the Z-direction linear module mounting base plate by bolt connection on both sides; the connecting plate 51 is connected by Bolt connection is fixed on the slide 24, which is convenient for connecting with the electric spindle fixing block 31 to drive it to move along the Z direction; the electric spindle fixing block 31 is fixed on the connecting plate 51 by bolt connection, and the electric spindle is fixed by flange connection fixing method; the Z-direction linear module mounting base plate is fixed on the connecting plate 51 of the X-direction linear module 1 by bolt connection, and the fixed position is two-thirds of the distance from the drive motor 21 of the Z-direction linear module 2, and the electric spindle fixing block 31 on it is fixed on the connecting plate 51 of the Z-direction linear module 2 by thread. In actual application, the corresponding cutting tool is installed on the electric spindle fixing block 31 to perform cutting operation.

[0042] Before the CNC cutting device of the present invention starts working, it is necessary to perform a self-check, which is specifically manifested as: the control system drives each motor to run at no load in turn, and checks whether the motor can start smoothly and reach the preset speed or position; it should be noted that when performing the self-check, the servo motors of the Y-direction linear module A3 and the Y-direction linear module B4 must perform a synchronous self-check.

[0043] The present invention is suitable for processing small workpieces. The drive motors 21 selected in the present invention are all high-speed DC motors, that is, to ensure that the entire device has sufficient driving force during operation; since the cutting device will generate vibration when working, it is necessary to control several main parts of the cutting device so that they cannot generate resonance, including the cutting device as a whole, the electric spindle and the gantry beam; therefore, when installing the Z-direction linear module 2, the position where the bolts are fixed is two-thirds of the distance from one end of the drive motor 21 of the Z-direction linear module 2.

[0044] Preferably, in order to further ensure the stability of the entire device, the machine tool installation base plate 5 adopts a steel plate composite structure, which can maximize the lightness while ensuring high stability. The cutting device body is made of gray cast iron, because it has good shock absorption, strength and rigidity, which can reduce the vibration generated by the cutting device during the processing and ensure the processing accuracy.

[0045] The control system of the small cutting device based on the novel gantry structure of the present invention decouples the design of the dual-axis control system in the Y direction through coordinate transformation, realizes the motion control of the Y-direction linear module A3 and the Y-direction linear module B4, thereby preventing the gantry from shifting, as follows:

[0046] First, we can consult the literature and know that the mechanical motion equation of permanent magnet synchronous motor (PMSM) is:

[0047]

[0048] Where M is the rotor mass, K is f is the thrust coefficient, C is the friction coefficient, F is the load impedance, i q is the stator current, is the rotor acceleration, is the rotor speed.

[0049] Let i q is the input, v is the output, then the transfer function of the object model is:

[0050]

[0051] The simplified dynamic model of the dual-axis motion system is:

[0052]

[0053] in, and They are the accelerations of the Y-direction linear module A3 and the Y-direction linear module B4, and are the speeds of the Y-direction linear module A3 and the Y-direction linear module B4, u y1 and u y2 They are the control inputs of the Y-direction linear module A3 and the Y-direction linear module B4 respectively. s only represents the order and has no practical meaning.

[0054] The position error is defined as the distance e between the expected position EP and the actual position AP, expressed as:

[0055] e=||AP-EP||

[0056] According to the two-dimensional coordinate transformation matrix:

[0057]

[0058] Among them, e y1 and e y2They are the motion errors of the slides on the Y-direction linear module A3 and the Y-direction linear module B4 respectively; t is the tangential error, e c is the contour error, and θ is the rotation angle between the actual coordinate system and the reference coordinate system.

[0059] Based on the dynamic model and error decomposition of the dual-axis system, the dynamic error equation is established:

[0060]

[0061] Among them, f y1 and f y2 is the dynamic model of the system in the y1-axis and y2-axis directions (i.e., the Y-direction linear module A3 and the Y-direction linear module B4 directions), C y1 and C y2 is the friction factor, K y1 and K y2 is the gain factor, and They are the speed errors during the movement of Y-direction linear module A3 and Y-direction linear module B4 respectively.

[0062] In this form, the error dynamics equation further describes how the system error changes over time, and the error in each direction can be controlled independently.

[0063] Based on the above model error and dynamic error equation, a contour error controller is constructed to ensure the accuracy and stability of the system:

[0064]

[0065] Among them, K d is the differential gain of the contour error, K i is the integral gain of the contour error, K c is the proportional gain of the contour error; is the speed error in the direction of the contour error; e c is the contour error; the above-derived and e y1 and e y2 Substitute and e c The corresponding error control acceleration is obtained In actual control, The numerical value uses a PID controller to adjust the Y-direction linear module drive motor output signal to control the error.

[0066] In the present invention, the motors of the Y-direction linear module A3 and the Y-direction linear module B4 are servo motors, and the two are always rotated synchronously to ensure that the X-direction linear module 1 runs normally without gantry offset;

[0067] The motor of the Z-direction linear module 2 in the present invention is a servo motor with a brake. When the motor stops working or loses power, the brake can automatically lock the motor shaft to prevent the Z-axis from sliding under the action of gravity.

[0068] The embodiments are preferred implementations of the present invention, but the present invention is not limited to the above-mentioned implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essential content of the present invention belong to the protection scope of the present invention.

Claims

1. A small cutting device based on a new gantry structure, characterized in that: The invention comprises an X-direction linear module (1), a Z-direction linear module (2), a Y-direction linear module A (3), a Y-direction linear module B (4), a machine tool mounting base plate (5), and a control system for comprehensively controlling the operation of a milling machine; the X-direction linear module (1), the Y-direction linear module A (3), and the Y-direction linear module B (4) have the same structural composition, wherein the Y-direction linear module A (3) and the Y-direction linear module B (4) are symmetrically arranged on the machine tool mounting base plate (5); the X-direction linear module (1) is mounted between the Y-direction linear module A (3) and the Y-direction linear module B (4), and the Z-direction linear module (2) is mounted on the X-direction linear module (1).

2. The small-sized cutting device based on the novel gantry structure according to claim 1 is characterized in that: The X-direction linear module (1) comprises an X-direction linear module mounting base plate (27), the two ends of the X-direction linear module mounting base plate (27) are respectively fixed with a motor mounting plate (22) and a screw mounting plate by bolts, a driving motor (21) is mounted on the motor mounting plate (22), a power output end of the driving motor (21) is connected to a screw (26) by a coupling (23), the other end of the screw (26) is mounted on the screw mounting plate, and the coupling (23) connects the driving motor (21) and the screw (26); the motor mounting plate (22) Two guide rails (25) are installed between the guide rails (25) and the screw rod installation plate by bolts, and the slide table (24) is slidably installed on the guide rails (25) and is threadedly matched with the screw rod (26); a connecting plate (51) is installed on the slide table (24) by bolts, and is used to connect the slide table (24) with the Z-direction linear module (2) through the connecting plate (51); the X-direction linear module installation base plate (27) is fixed to the connecting plates (51) of the Y-direction linear module A (3) and the Y-direction linear module B (4) by bolts and an L-shaped connecting block (41).

3. The small-sized cutting device based on the novel gantry structure according to claim 2 is characterized in that: The Z-direction linear module (2) also includes a drive motor (21), a motor mounting plate (22), a coupling (23), a slide table (24), a guide rail (25), a screw rod (26), a connecting plate (51), and a Z-direction linear module mounting base plate, and the mounting method between the various components is the same as that of the X-direction linear module (1); the Z-direction linear module (2) also includes an electric spindle fixing block (31); In the Z-direction linear module (2), the connecting plate (51) is fixed to the slide table (24) by bolts, and is used to connect with the electric spindle fixing block (31) to drive it to move along the Z direction; the Z-direction linear module mounting base plate is fixed to the connecting plate (51) of the X-direction linear module (1) by bolts, and the fixing position is two-thirds of the distance from the driving motor (21) of the Z-direction linear module (2).

4. The small-sized cutting device based on the novel gantry structure according to claim 1 is characterized in that: The control system decouples the design of the dual-axis control system in the Y direction through coordinate transformation, realizes the motion control of the Y-direction linear module A (3) and the Y-direction linear module B (4), thereby preventing the gantry from offsetting, as follows: The mechanical motion equation of a permanent magnet synchronous motor is: Where M is the rotor mass, K is f is the thrust coefficient, C is the friction coefficient, F is the load impedance, i q is the stator current, is the rotor acceleration, is the rotor speed; Let i q is the input, v is the output, then the transfer function of the object model is: The simplified dynamic model of the dual-axis motion system is: in, and They are the accelerations of the Y-direction linear module A (3) and the Y-direction linear module B (4), and are the speeds of the Y-direction linear module A (3) and the Y-direction linear module B (4), u y1 and u y2 They are the control inputs of the Y-direction linear module A (3) and the Y-direction linear module B (4) respectively; The position error is defined as the distance e between the expected position EP and the actual position AP, expressed as: e=||AP-EP|| According to the two-dimensional coordinate transformation matrix: Among them, e y1 and e y2 They are the motion errors of the slides on the Y-direction linear module A (3) and the Y-direction linear module B (4); e t is the tangential error, e c is the contour error, θ is the rotation angle between the actual coordinate system and the reference coordinate system; Based on the dynamic model and error decomposition of the dual-axis system, the dynamic error equation is established: Among them, f y1 and f y2 is the dynamic model of the system in the y1-axis and y2-axis directions, C y1 and C y2 is the friction factor, K y1 and K y2 is the gain factor, and They are the velocity errors of the Y-direction linear module A (3) and the Y-direction linear module B (4) during the motion process; The dynamic error equation further describes the change of system error over time, and the error in each direction can be controlled independently. Based on the model error and the dynamic error equation, a contour error controller is constructed to ensure the accuracy and stability of the system: Among them, K d is the differential gain of the contour error, K i is the integral gain of the contour error, K c is the proportional gain of the contour error; is the speed error in the direction of the contour error; e c is the contour error; the above calculated and e y1 and e y2 Substitute and e c The corresponding error control acceleration is obtained In actual control, The numerical value uses a PID controller to adjust the Y-direction linear module drive motor output signal to control the error.

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