A high-precision free-sweeping displacement mechanism and control method

Abstract

This invention relates to a high-precision conformal free-flowing push-broom displacement mechanism and control method, applied to the conformal free-flowing push-broom and precise positioning in large-size, high-precision ceramic photopolymerization / fiber-toughened composite additive manufacturing equipment. The displacement mechanism includes a marble stage, an X-axis displacement subsystem, a Y-axis displacement subsystem, and a Z-axis displacement subsystem. The X-axis displacement subsystem is located on the upper side of the marble stage, the Y-axis displacement subsystem is located on the X-axis displacement subsystem, and the Z-axis displacement subsystem is located on the Y-axis displacement subsystem. The displacement mechanism can achieve movement in three directions (X, Y, and Z). The X, Y, and Z axes all employ rotary motors driving enclosed ball screws to achieve high-precision linear motion.

Description

Technical Field

[0001] This invention relates to a high-precision conformal free-sweeping displacement mechanism and control method, which is applied to the conformal free-sweeping and precise positioning in large-size, high-precision ceramic photopolymerization / fiber toughening composite additive manufacturing equipment. Background Technology

[0002] Advanced complex ceramic components are a crucial foundation for the development of my country's next-generation strategic emerging industries such as aviation and aerospace. Large-size, complex-structured special ceramic key components in key fields such as aviation, aerospace, and energy and chemical engineering have an urgent need for high-precision equipment. Large-size, high-precision ceramic additive manufacturing equipment is a revolutionary technology for realizing the forming of complex ceramic components. The high-precision following free-push-broom displacement mechanism and control method in large-size, high-precision ceramic additive manufacturing equipment are a key link in realizing the photopolymerization / fiber-toughened composite forming process. Traditional displacement mechanisms use single-sided drive on the X-axis, resulting in small thrust, slow response speed, and weak anti-interference ability. Especially during free-push-brooming, the Y-axis moves rapidly under heavy load. When the Y-axis load is near the motor side and far from the motor side, the thrust requirements of the asymmetrical single-sided motor differ significantly, causing large thrust fluctuations and posing a serious challenge to motor performance. Therefore, a symmetrical, double-sided redundant drive X-axis configuration is proposed, with one motor driving each side of the X-axis. This ensures that regardless of which side the Y-axis load is on, the corresponding motor outputs power. This symmetrical structure reduces motor thrust fluctuations, enhances anti-interference capabilities, and provides high thrust and fast response from the dual motors. However, this redundant drive configuration also presents challenges to motion control methods. Specifically, the synchronous control of the dual motors must be guaranteed. Otherwise, the two parallel axes will pull on each other, affecting the accuracy of the accompanying free-sweeping motion and even damaging the mechanical mechanism. In summary, there is an urgent need to propose a symmetrical, double-sided driven accompanying free-sweeping displacement mechanism, and to develop a corresponding high-precision accompanying free-sweeping motion and high-performance dual-motor synchronous motion control method. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, this invention provides a high-precision conformal free push-broom displacement mechanism and control method. The displacement mechanism can realize movement in three directions: X, Y, and Z. The X-axis, Y-axis, and Z-axis all use rotary motors to drive enclosed ball screws to achieve high-precision linear motion.

[0004] A high-precision conformal free-sweeping displacement mechanism for large-size ceramic photopolymerization spray deposition composite molding includes a marble platform, an X-axis displacement subsystem, a Y-axis displacement subsystem, and a Z-axis displacement subsystem. The X-axis displacement subsystem is arranged on the upper side of the marble platform, the Y-axis displacement subsystem is arranged on the X-axis displacement subsystem, and the Z-axis displacement subsystem is arranged on the Y-axis displacement subsystem.

[0005] The marble platform includes a rubber damping bracket, a work surface, and an X-axis module mounting base. The work surface is provided on the upper side of the rubber damping bracket, and two X-axis module mounting bases are symmetrically arranged on the upper side of the work surface.

[0006] The marble platform is used to install the displacement mechanism and serves as the mounting support for the entire displacement mechanism.

[0007] The X-axis displacement subsystem includes a rotary motor, a closed ball screw, and an optical encoder. The X-axis displacement subsystem is mounted on an X-axis module mounting base on a marble platform and includes two symmetrically arranged, parallel closed ball screws driven by the rotary motor. An optical encoder is mounted on one side of the closed ball screw, which can measure the displacement of the movable part of the closed ball screw.

[0008] The X-axis displacement subsystem can drive the Y-axis displacement subsystem and its load to achieve displacement along the X-axis.

[0009] The Y-axis displacement subsystem includes an XY-axis connecting plate, a crossbeam, a second enclosed ball screw, a second rotary motor, a guide rail, and a second grating encoder. The Y-axis displacement subsystem is mounted across the X-axis displacement subsystem. The second enclosed ball screw is mounted above the crossbeam and is driven by the second rotary motor. A guide rail is mounted on the side of the crossbeam for mounting and guiding the Z-axis. A second grating encoder is mounted on the rear side of the second enclosed ball screw, capable of measuring its displacement. A third grating encoder is mounted on the right side of the fourth enclosed ball screw, capable of measuring the displacement of its mover.

[0010] The Y-axis displacement subsystem can drive the Z-axis and its load to achieve displacement along the Y-axis.

[0011] The Z-axis displacement subsystem is mounted on the mover of the Y-axis displacement subsystem. The Z-axis displacement subsystem includes a module mounting plate, a third enclosed ball screw, a third rotary motor, a fourth enclosed ball screw, a fourth rotary motor, a YZ-axis connecting plate, and a third grating encoder. The YZ-axis connecting plate connects the mover of the Y-axis displacement subsystem to the module mounting plate on the Z-axis displacement subsystem. The third and fourth enclosed ball screws are mounted side by side on the module mounting plate to enable the mover of the Z-axis displacement subsystem to move up and down along the Z-axis. The third rotary motor drives the third enclosed ball screw, and the fourth rotary motor drives the fourth enclosed ball screw.

[0012] The third enclosed ball screw is used to install the fiber toughening module and realize its up-and-down movement along the Z-axis, and the fourth enclosed ball screw is used to install the accompanying photocuring module and realize its up-and-down movement along the Z-axis.

[0013] A two-dimensional motion control method for a high-precision conformal free-flowing push-broom displacement mechanism includes the following steps:

[0014] Step 1: First, analyze the configuration of the displacement mechanism, draw the free body diagram of the displacement mechanism, and derive the cross-coupled dynamic equations of the displacement mechanism using the Lagrange method;

[0015] Step 2: Based on the shape and trajectory of the printed slice, the desired free-following sweep trajectory is planned. The position information of the ball screw mover is obtained based on the feedback from the motor encoder, and then the tracking error between the actual sweep trajectory and the desired sweep trajectory is obtained.

[0016] Step 3: Write the cross-coupling dynamic equations in a parametrically linearized form, where the dynamic parameters are updated by an adaptive law based on the tracking error. Substitute the desired trajectory into the dynamic equations to calculate the thrust that the motor should theoretically exert to achieve the desired trajectory, and use it as a feedforward control signal.

[0017] Step 4: Feedback control adopts proportional-derivative control. The error signal is passed through the proportional-derivative element to obtain the feedback control signal, which is used to handle model errors and external disturbances, and enhance the robustness of the closed-loop control system.

[0018] Step 5: Use Lyapunov theory to prove the stability of the entire closed-loop control system; superimpose the feedforward control signal and the feedback control signal as the overall control signal and send it to each axis motor, thereby realizing XY axis linkage cross-coupling control and achieving high-precision following free push sweep.

[0019] The beneficial effects of the high-precision conformal free-flowing push-broom displacement mechanism and control method of the present invention are:

[0020] The displacement mechanism can move the photopolymerization module and fiber toughening module of the additive manufacturing equipment, realizing their functions and switching coordination to complete large-size ceramic composite molding. The grating encoder can provide real-time feedback on the position information of the lead screw mover, which can be used as closed-loop control of the mover's motion. Based on the configuration of the displacement mechanism, the dynamic model of the displacement mechanism can be derived using the Lagrange method, thereby realizing a model-based adaptive feedforward + robust control feedback binary control method. Attached Figure Description

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific implementation methods.

[0022] Figure 1 This is an overall diagram of a high-precision following free push-sweep displacement mechanism;

[0023] Figure 2 This is a schematic diagram of a marble countertop;

[0024] Figure 3This is a schematic diagram of the X-axis displacement subsystem;

[0025] Figure 4 Schematic diagram of the Y-axis displacement subsystem Figure 1 ;

[0026] Figure 5 Schematic diagram of the Y-axis displacement subsystem Figure 2 ;

[0027] Figure 6 Schematic diagram of the Z-axis displacement subsystem Figure 1 ;

[0028] Figure 7 Schematic diagram of the Z-axis displacement subsystem Figure 2 ;

[0029] Figure 8 This is a schematic diagram of a two-dimensional motion control method.

[0030] In the diagram: X-axis displacement subsystem 11; Y-axis displacement subsystem 12; Z-axis displacement subsystem 13; marble table 14;

[0031] 21. Rubber damping bracket; 22. Worktable surface; 23. X-axis module mounting base;

[0032] Rotary motor 31; Enclosed ball screw 32; Optical encoder 33;

[0033] XY axis connecting plate 41; crossbeam 42; enclosed ball screw II 43; rotary motor II 44; guide rail 45; grating encoder II 46;

[0034] Enclosed ball screw 3 51; Rotary motor 3 52; Enclosed ball screw 4 53; Rotary motor 4 54; YZ axis connecting plate 55; Grating encoder 3 56. Detailed Implementation

[0035] like Figure 1-8 As shown, the present invention mainly proposes a high-precision conformal free-sweeping displacement mechanism and control method. A high-precision conformal free-sweeping displacement mechanism for large-size ceramic photopolymerization spray deposition composite molding includes a marble stage 14, an X-axis displacement subsystem 11, a Y-axis displacement subsystem 12, and a Z-axis displacement subsystem 13. The X-axis displacement subsystem 11 is arranged on the upper side of the marble stage 14, the Y-axis displacement subsystem 12 is arranged on the X-axis displacement subsystem 11, and the Z-axis displacement subsystem 13 is arranged on the Y-axis displacement subsystem 12.

[0036] The marble platform 14 includes a rubber damping bracket 21, a work surface 22, and an X-axis module mounting base 23. The work surface 22 is provided on the upper side of the rubber damping bracket 21, and two X-axis module mounting bases 23 are symmetrically arranged on the upper side of the work surface 22.

[0037] The marble platform 14 is used to install the displacement mechanism and serves as the mounting support for the entire displacement mechanism.

[0038] The function of the rubber damping bracket 21 is to support the marble countertop and to buffer and isolate vibrations from the marble countertop and the ground.

[0039] The X-axis displacement subsystem 11 includes a rotary motor 31, a closed ball screw 32, and a grating encoder 33. The X-axis displacement subsystem 11 is mounted on an X-axis module mounting base 23 on a marble platform 14. It includes two symmetrically arranged, parallel closed ball screws 32, which are driven by the rotary motor 31. A grating encoder 33 is mounted on one side of the closed ball screw 32, which can measure the displacement of the mover of the closed ball screw 32.

[0040] The X-axis displacement subsystem 11 can drive the Y-axis displacement subsystem 12 and its load to achieve displacement along the X-axis.

[0041] The Y-axis displacement subsystem 12 includes an XY-axis connecting plate 41, a crossbeam 42, a second enclosed ball screw 43, a second rotary motor 44, a guide rail 45, and a second grating encoder 46. The Y-axis displacement subsystem 12 is mounted across the X-axis displacement subsystem 11. The second enclosed ball screw 43 is mounted above the crossbeam 42 and is driven by the second rotary motor 44. The guide rail 45 is mounted on the side of the crossbeam 42 for mounting and guiding the Z-axis. The second grating encoder 46 is mounted on the rear side of the second enclosed ball screw 43 to measure its displacement. The third grating encoder 56 is mounted on the right side of the fourth enclosed ball screw 53 to measure its displacement.

[0042] The Y-axis displacement subsystem 12 can drive the Z-axis and its load to achieve displacement along the Y-axis.

[0043] The Z-axis displacement subsystem 13 is mounted on the mover of the Y-axis displacement subsystem 12. The Z-axis displacement subsystem 13 includes a module mounting plate, a closed ball screw 51, a rotary motor 52, a closed ball screw 53, a rotary motor 54, a YZ-axis connecting plate 55, and a grating encoder 56. The YZ-axis connecting plate 55 is used to connect the mover of the Y-axis displacement subsystem 12 and the module mounting plate on the Z-axis displacement subsystem 13. The closed ball screws 51 and 53 are mounted side by side on the module mounting plate to realize the up and down movement of the mover on the Z-axis displacement subsystem 13 along the Z-axis. The rotary motor 52 drives the closed ball screw 51, and the rotary motor 54 drives the closed ball screw 53.

[0044] The enclosed ball screw 3 51 is used to install the fiber toughening module and realize its up-and-down movement along the Z-axis, and the enclosed ball screw 4 53 is used to install the accompanying photocuring module and realize its up-and-down movement along the Z-axis.

[0045] When the displacement mechanism is working, a rotary motor receives a control signal and rotates according to the signal. This rotation is converted into linear motion of a slider along the guide rail via a ball screw, driving the load to achieve linear displacement. The X-axis displacement subsystem 11 and Y-axis displacement subsystem 12 work together to drive the Z-axis displacement subsystem 13 and its load to achieve free planar sliding. A fiber-reinforcing module is installed on the enclosed ball screw 3 51, enabling its up-and-down movement along the Z-axis. A photocuring module is installed on the enclosed ball screw 4 53, also enabling its up-and-down movement along the Z-axis. Combined with the XY-axis displacement, precise positioning is achieved in the XYZ three-dimensional space. The enclosed ball screws 3 51 and 4 53 respectively drive the fiber laying and photocuring modules up-and-down movements, achieving a combined molding process for both functions.

[0046] The binary motion control method is used for the XY-axis linkage cross-coupled motion control of the displacement mechanism, thereby achieving high-precision following free push-sweep. It includes adaptive feedforward control based on the dynamic model of the displacement mechanism and robust feedback control based on proportional-integral-derivative (PID). Feedforward control is used to accelerate the response speed and compensate for motor thrust fluctuations caused by rapid load movement, while feedback control is used to handle external disturbances and ensure the robustness of the closed-loop system.

[0047] The binary motion control method provides control signals to a rotating motor to achieve XY-axis linkage and cross-coupling motion control. The specific steps are as follows:

[0048] Step 1: First, analyze the configuration of the displacement mechanism, draw the free body diagram of the displacement mechanism, and derive the cross-coupled dynamic equations of the displacement mechanism using the Lagrange method;

[0049] Step 2: Based on the shape and trajectory of the printed slice, the desired free-following sweep trajectory is planned. The position information of the ball screw mover is obtained based on the feedback from the motor encoder, and then the tracking error between the actual sweep trajectory and the desired sweep trajectory is obtained.

[0050] Step 3: Write the cross-coupling dynamic equations in a parametrically linearized form, where the dynamic parameters are updated by an adaptive law based on the tracking error. Substitute the desired trajectory into the dynamic equations to calculate the thrust that the motor should theoretically exert to achieve the desired trajectory, and use it as a feedforward control signal.

[0051] Step 4: Feedback control adopts proportional-derivative control. The error signal is passed through the proportional-derivative element to obtain the feedback control signal, which is used to handle model errors and external disturbances, and enhance the robustness of the closed-loop control system.

[0052] Step 5: Use Lyapunov theory to prove the stability of the entire closed-loop control system; superimpose the feedforward control signal and the feedback control signal as the overall control signal and send it to each axis motor, thereby realizing XY axis linkage cross-coupling control and achieving high-precision following free push sweep.

[0053] The specific implementation method of the binary control method is as follows:

[0054] The aforementioned binary control method consists of two parts: feedforward control based on the dynamic model as one part and feedback control using proportional-derivative control as another part. The binary control method is a superposition of "feedforward control + feedback control". Figure 8 The flowchart below illustrates the control method. The specific implementation method is as follows: the control law of the control method can be obtained; a control program is written in Matlab / Simulink based on the control law; the program is compiled and loaded into the dSPACE MicroLab Box real-time machine; the real-time machine calculates the control law to obtain the control signal, which is then sent to the motor driver.

Claims

1. A two-dimensional motion control method for a high-precision conformal free-flowing push-broom displacement mechanism, characterized in that, Includes the following steps: Step 1: First, analyze the configuration of the displacement mechanism, draw the free body diagram of the displacement mechanism, and derive the cross-coupled dynamic equations of the displacement mechanism using the Lagrange method; Step 2: Based on the shape and trajectory of the printed slice, the desired free-following sweep trajectory is planned. The position information of the ball screw mover is obtained based on the feedback from the motor encoder, and then the tracking error between the actual sweep trajectory and the desired free-following sweep trajectory is obtained. Step 3: Write the cross-coupled dynamic equations in a parametrically linearized form, where the dynamic parameters are updated by an adaptive law based on the tracking error. Substitute the desired trajectory into the dynamic equations to calculate the theoretical thrust that the accompanying free push sweeping trajectory motor should exert to achieve the desired trajectory, and use it as a feedforward control signal. Step 4: Feedback control adopts proportional-derivative control. The error signal is passed through the proportional-derivative element to obtain the feedback control signal, which is used to handle model errors and external disturbances, and enhance the robustness of the closed-loop control system. Step 5: Use Lyapunov theory to prove the stability of the entire closed-loop control system; superimpose the feedforward control signal and the feedback control signal as the overall control signal and send it to each axis motor, thereby realizing XY axis linkage cross-coupling control and achieving high-precision following free push sweep.

2. The two-dimensional motion control method for a high-precision conformal free-flowing push-broom displacement mechanism according to claim 1, characterized in that: The method relates to a high-precision conformal free push-broom displacement mechanism, including a marble platform (14), an X-axis displacement subsystem (11), a Y-axis displacement subsystem (12) and a Z-axis displacement subsystem (13), characterized in that: an X-axis displacement subsystem (11) is provided on the upper side of the marble platform (14), a Y-axis displacement subsystem (12) is provided on the X-axis displacement subsystem (11), and a Z-axis displacement subsystem (13) is provided on the Y-axis displacement subsystem (12); The marble platform (14) includes a rubber damping bracket (21), a work surface (22), and an X-axis module mounting base (23). The work surface (22) is provided on the upper side of the rubber damping bracket (21), and two X-axis module mounting bases (23) are symmetrically arranged on the upper side of the work surface (22). The marble platform (14) is used to install the displacement mechanism and serves as the mounting support for the entire displacement mechanism.

3. The two-dimensional motion control method for a high-precision conformal free-flowing push-broom displacement mechanism according to claim 2, characterized in that: The X-axis displacement subsystem (11) includes a rotary motor (31), a closed ball screw (32), and a grating encoder (33). The X-axis displacement subsystem (11) is mounted on an X-axis module mounting base (23) on a marble table (14). It includes two symmetrically arranged, parallel closed ball screws (32), which are driven by the rotary motor (31). A grating encoder (33) is installed on one side of the closed ball screw (32) to measure the displacement of the mover of the closed ball screw (32).

4. The two-dimensional motion control method for a high-precision conformal free-flowing push-broom displacement mechanism according to claim 3, characterized in that: The X-axis displacement subsystem (11) can drive the Y-axis displacement subsystem (12) and its load to achieve displacement along the X-axis.

5. The two-dimensional motion control method for a high-precision conformal free-flowing push-broom displacement mechanism according to claim 4, characterized in that: The Y-axis displacement subsystem (12) includes an XY-axis connecting plate (41), a crossbeam (42), a second enclosed ball screw (43), a second rotary motor (44), a guide rail (45), and a second grating encoder (46). The Y-axis displacement subsystem (12) is mounted across the X-axis displacement subsystem (11). The second enclosed ball screw (43) is mounted above the crossbeam (42) and is driven by the second rotary motor (44). The guide rail (45) is mounted on the side of the crossbeam (42) for mounting and guiding the Z-axis. The second grating encoder (46) is mounted on the rear side of the second enclosed ball screw (43) and can measure the displacement of the second enclosed ball screw (43).

6. The two-dimensional motion control method for a high-precision conformal free-flowing push-broom displacement mechanism according to claim 5, characterized in that: The Y-axis displacement subsystem (12) can drive the Z-axis and its load to achieve displacement along the Y-axis.

7. The two-dimensional motion control method for a high-precision conformal free-flowing push-broom displacement mechanism according to claim 6, characterized in that: The Z-axis displacement subsystem (13) is mounted on the mover of the Y-axis displacement subsystem (12). The Z-axis displacement subsystem (13) includes a module mounting plate, a closed ball screw three (51), a rotary motor three (52), a closed ball screw four (53), a rotary motor four (54), a YZ axis connecting plate (55), and a grating encoder three (56). The YZ axis connecting plate (55) is used to connect the mover of the Y-axis displacement subsystem (12) and the module mounting plate on the Z-axis displacement subsystem (13). The enclosed ball screw three (51) and enclosed ball screw four (53) are mounted side by side on the module mounting plate to realize the up and down movement of the mover on the Z-axis displacement subsystem (13) along the Z-axis. The rotary motor three (52) drives the enclosed ball screw three (51), and the rotary motor four (54) drives the enclosed ball screw four (53). The right side of the enclosed ball screw four (53) is equipped with a grating encoder three (56) which can measure the displacement of the mover of the enclosed ball screw four (53).

8. A two-dimensional motion control method for a high-precision conformal free-flowing push-broom displacement mechanism according to claim 7, characterized in that: The enclosed ball screw three (51) is used to install the fiber toughening module and realize its up and down movement along the Z-axis, and the enclosed ball screw four (53) is used to install the accompanying photocuring module and realize its up and down movement along the Z-axis.

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