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CN-122008556-A - Motion control method and system for bipolar coordinate 3D printer

CN122008556ACN 122008556 ACN122008556 ACN 122008556ACN-122008556-A

Abstract

The invention discloses a motion control method and a motion control system for a bipolar coordinate 3D printer, and belongs to the technical field of additive manufacturing. Aiming at the technical defects that the existing bipolar coordinate printer has complex kinematic model and poor calculation instantaneity, the invention establishes an optimization model based on isosceles triangle geometric relationship by fixedly arranging the swing arm rotation center O 1 on the X axis (a, 0) or the Y axis (0, a) of a carrier coordinate system and restricting the length L of the swing arm to be equal to the distance a. Based on the geometric constraint, a deterministic closed solution for directly calculating the swing arm rotation angle phi and the carrier rotation angle theta from the model coordinates (x, y) is deduced, and the iteration solution requirement in the traditional method is thoroughly eliminated. The system supports precision controllable mechanisms based on approximate calculation such as a table look-up method, a CORDIC algorithm and the like, and multi-print-head phase compensation cooperative scheduling. The calculation instantaneity is obviously improved while the printing precision is ensured, and the multi-material printing function is realized.

Inventors

  • YANG XIAOHONG

Assignees

  • 杨晓宏

Dates

Publication Date
20260512
Application Date
20260130
Priority Date
20250516

Claims (10)

  1. 1. The motion control method of the bipolar coordinate 3D printer is characterized in that the bipolar coordinate 3D printer comprises a sliding sleeve axle center (O 1 ) which is fixedly arranged, a carrying platform which can rotate around a carrying platform center (O), and a swinging arm, wherein one end of the swinging arm is rotationally connected with the sliding sleeve axle center (O 1 ) and the other end of the swinging arm is provided with a printing head, the sliding sleeve axle center (O 1 ) is positioned at (a, 0) or (0, a), and the length L of the swinging arm is equal to the distance a from the sliding sleeve axle center to the carrying platform center; the method comprises the following steps: S1, acquiring coordinates (x, y) of a target printing point P in a model coordinate system, wherein the model coordinate system is fixedly connected with the carrier, and the origin of the model coordinate system coincides with the center of the carrier; S2, calculating polar coordinate parameters of the target printing point, including polar diameter And polar angle θ 0 =atan2 (y, x); s3, selecting a corresponding preset calculation formula according to the position of the axis of the sliding sleeve in a fixed coordinate system, and solving a swing arm rotation angle phi and a carrier rotation angle theta required by the printing head to reach the target printing point, wherein the preset calculation formula is determined through a triangle geometry relation based on geometric constraint of L=a, and the swing arm rotation angle phi is constrained in a [0, pi ] interval so as to limit the swing arm not to rotate in the whole circle; And S4, driving the carrying platform to rotate by the carrying platform rotation angle theta, and simultaneously driving the swing arm to rotate by the swing arm rotation angle phi around the axis of the sliding sleeve, so that the printing head moves to the target printing point P.
  2. 2. The method according to claim 1, wherein in step S3, when the sliding sleeve axis O 1 is located at (a, 0), the swing arm rotation angle Φ is an angle between the swing arm and the positive direction of the X-axis, and the preset calculation formula includes: Calculating an auxiliary angle β, wherein β= arccos (ρ/(2 a)); Determining the swing arm rotation angle phi = 2 beta; determining the carrier rotation angle θ=β - θ 0 ; where θ=0 and Φ=pi when ρ=0, and θ=atan2 (y, x) -pi/2 and Φ=0 when ρ=2a, to ensure angular continuity.
  3. 3. The method according to claim 1, wherein in step S3, when the sliding sleeve axis O 1 is located at (0, a), the swing arm rotation angle Φ is an angle between the swing arm and the negative Y-axis direction, and the preset calculation formula includes: Determining the swing arm rotation angle phi = arccos (1-p 2 /(2a 2 )); Determining the rotation angle theta = phi/2-theta 0 of the carrier; Where θ=0 and Φ=0 when ρ=2a, and θ=atan2 (y, x) -pi/2 and Φ=pi when ρ=2a, to ensure angular continuity.
  4. 4. A motion control method according to claim 2 or 3, characterized in that in step S3, the calculation of the inverse cosine function arccos is implemented using an approximation calculation method, the calculation error of which is configured to meet the preset printing accuracy requirement of the printer.
  5. 5. The method of claim 1, further comprising the step of controlling the printhead to move in a vertical direction according to the Z-coordinate of the target print point P.
  6. 6. A bipolar coordinate 3D printer motion control system for implementing the method of any of claims 1-5, comprising: the coordinate system configuration module is used for establishing and maintaining the fixed coordinate system; the track generation module is used for generating a coordinate sequence of the target point; An inverse kinematics calculation module configured to calculate a swing arm rotation angle phi and a stage rotation angle theta from target point coordinates using the calculation formula of claim 2 or 3 based on the calculation formula described by the l=a and O 1 (a, 0) or O 1 (0, a); And the cooperative motion control module is used for driving the actuating mechanism according to phi and theta.
  7. 7. A bipolar coordinate 3D printer is characterized by comprising a motion control system according to claim 6, wherein the mechanical structure is configured such that the swing arm rotates around a fixedly arranged sliding sleeve axis (O 1 ), the fixedly arranged sliding sleeve axis (O 1 ) is positioned in the positive direction of the X axis or the Y axis of the center (O) of the carrier, the distance is a, and the length of the swing arm is equal to a.
  8. 8. The bipolar coordinate 3D printer of claim 7 further comprising a Z-direction relative motion mechanism for effecting relative motion of the printhead and print carriage in a Z-axis direction.
  9. 9. The bipolar coordinate 3D printer of claim 7, wherein the swing arm is of a disc-shaped structure and forms a rotary table, at least two printing heads are arranged on the periphery of the rotary table along the circumferential direction, the distance from an extrusion opening of each printing head to the rotary center of the rotary table is a, and each printing head has a preset installation phase angle delta i .
  10. 10. The bi-polar 3D printer of claim 7, wherein the motion control system further comprises: The printing head selecting and scheduling module is used for dynamically selecting an activated printing head from the plurality of printing heads according to the requirement of the current printing task; And the phase compensation module is used for compensating the first rotation angle theta calculated by the inverse kinematics calculation module according to the fixed installation phase angle delta i of the selected printing head to obtain an actual instruction angle theta' =theta-delta i for driving the turntable to rotate, and correcting the printing starting position according to the calibration value of the phase angle delta i .

Description

Motion control method and system for bipolar coordinate 3D printer Technical Field The invention relates to the technical field of additive manufacturing, in particular to a 3D printer motion control method, system and printer equipment based on an optimized bipolar coordinate system. Background Existing 3D printers mainly use cartesian coordinates or unipolar coordinate systems. The multipole coordinate system has the potential advantage of being simple and compact in structure as an emerging alternative. In the prior art, CN107738444A discloses a 3D printer adopting bipolar coordinates, which is formed by a horizontally and linearly movable sliding block and a rotatable printing spray head to form a serial bipolar coordinate system, the scheme has the obvious defects that a kinematic model depends on a complex binary nonlinear equation set (X= (a) cosA) (B cosB) and Y=a sinA +b sinB), the solving calculation amount is large, multiple solutions or iteration requirements exist, real-time requirements are difficult to meet under a high-speed printing scene, and CN110341190B and CN120134616A disclose 3D printer structures based on the multipole coordinates, but neither discloses a specific algorithm of motion control. In addition, the technical scheme of the patent does not relate to functions such as multi-print head integration and self-adaptive precision control. Therefore, the conventional multipole coordinate printer still has the technical bottlenecks of complex motion control algorithm, poor instantaneity and single function, and restricts the practical application of the multipole coordinate printer in the fields of high-speed high-precision and multi-material printing. The application is an improvement based on the prior application CN120134616A, and is especially innovative to the control algorithm which is not disclosed. Disclosure of Invention The invention aims to overcome the defects of complex motion control algorithm, poor instantaneity and insufficient function expansibility of the existing bipolar coordinate 3D printer, and provides a motion control method and system which are efficient in calculation, good in instantaneity and support multifunctional integration. In order to achieve the above purpose, the core concept of the invention is that the swing arm rotation center (sliding sleeve axis) O 1 is optimally arranged at a fixed position (a, 0) or (0, a) of a carrier coordinate system X or Y axis, L=a is restrained, a simplified model based on isosceles triangle geometric relationship is established, and a direct calculation formula is deduced according to triangle cosine theorem, so that the iterative solution of the traditional complex equation system is replaced. In order to achieve the above object, the present invention provides a motion control method for a bipolar coordinate 3D printer, wherein the bipolar coordinate 3D printer includes a fixedly disposed sliding sleeve axis (O 1), a stage rotatable about a stage center (O), and a swing arm having one end rotatably connected to the sliding sleeve axis (O 1) and the other end provided with a print head, the sliding sleeve axis (O 1) is located at (a, 0) or (0, a), and a length L of the swing arm (a distance from an extrusion port of the print head to the sliding sleeve axis) is equal to a distance a from the sliding sleeve axis to the stage center, the method includes the following steps: S1, acquiring coordinates (x, y) of a target printing point P in a model coordinate system, wherein the model coordinate system is fixedly connected with the carrier, and the origin of the model coordinate system coincides with the center of the carrier; s2, calculating polar coordinate parameters of the target printing point, wherein the polar coordinate parameters comprise: Polar diameter: ; Polar angle θ 0 =atan2 (y, x); S3, selecting a corresponding preset calculation formula according to the position of the axis of the sliding sleeve in a fixed coordinate system, and solving a swing arm rotation angle phi and a carrier rotation angle theta required by the printing head to reach the target printing point, wherein the preset calculation formula is determined through a triangle geometry relation based on geometric constraint of L=a, and the swing arm rotation angle phi is constrained in a [0, pi ] interval; And S4, driving the carrying platform to rotate by the carrying platform rotation angle theta, and simultaneously driving the swing arm to rotate by the swing arm rotation angle phi around the axis of the sliding sleeve, so that the printing head moves to the target printing point P. Further, in step S3, when the sliding sleeve axis O 1 is located at (a, 0), the swing arm rotation angle Φ is an included angle between the swing arm and the positive direction of the X axis, and the preset calculation formula includes: Calculating an auxiliary angle β, wherein β= arccos (ρ/(2 a)); Determining the swing arm rotation angle phi = 2 beta; and determin