WO2018112770A1 - 多轴机械系统与视觉监视相结合的3d打印方法与装置 - Google Patents

多轴机械系统与视觉监视相结合的3d打印方法与装置 Download PDF

Info

Publication number
WO2018112770A1
WO2018112770A1 PCT/CN2016/111194 CN2016111194W WO2018112770A1 WO 2018112770 A1 WO2018112770 A1 WO 2018112770A1 CN 2016111194 W CN2016111194 W CN 2016111194W WO 2018112770 A1 WO2018112770 A1 WO 2018112770A1
Authority
WO
WIPO (PCT)
Prior art keywords
printing
module
printed
freedom
degree
Prior art date
Application number
PCT/CN2016/111194
Other languages
English (en)
French (fr)
Inventor
毋立芳
于淼
赵立东
高源�
郭小华
王昌凌
张子明
施远征
简萌
Original Assignee
北京工业大学
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 北京工业大学 filed Critical 北京工业大学
Priority to CN201680074907.XA priority Critical patent/CN109414881A/zh
Priority to PCT/CN2016/111194 priority patent/WO2018112770A1/zh
Publication of WO2018112770A1 publication Critical patent/WO2018112770A1/zh
Priority to US16/446,314 priority patent/US11225018B2/en

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
    • B29C64/10—Processes of additive manufacturing
    • B29C64/106—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
    • B29C64/118—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material using filamentary material being melted, e.g. fused deposition modelling [FDM]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
    • B29C64/20—Apparatus for additive manufacturing; Details thereof or accessories therefor
    • B29C64/227—Driving means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
    • B29C64/20—Apparatus for additive manufacturing; Details thereof or accessories therefor
    • B29C64/227—Driving means
    • B29C64/241—Driving means for rotary motion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
    • B29C64/20—Apparatus for additive manufacturing; Details thereof or accessories therefor
    • B29C64/245—Platforms or substrates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
    • B29C64/30—Auxiliary operations or equipment
    • B29C64/379—Handling of additively manufactured objects, e.g. using robots
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C67/00—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y40/00—Auxiliary operations or equipment, e.g. for material handling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y50/00—Data acquisition or data processing for additive manufacturing
    • B33Y50/02—Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00—Programme-control systems
    • G05B19/02—Programme-control systems electric
    • G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
    • G05B19/4097—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by using design data to control NC machines, e.g. CAD/CAM
    • G05B19/4099—Surface or curve machining, making 3D objects, e.g. desktop manufacturing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
    • B29C64/20—Apparatus for additive manufacturing; Details thereof or accessories therefor
    • B29C64/205—Means for applying layers
    • B29C64/209—Heads; Nozzles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
    • B29C64/30—Auxiliary operations or equipment
    • B29C64/386—Data acquisition or data processing for additive manufacturing
    • B29C64/393—Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y10/00—Processes of additive manufacturing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y30/00—Apparatus for additive manufacturing; Details thereof or accessories therefor
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00—Program-control systems
    • G05B2219/30—Nc systems
    • G05B2219/49—Nc machine tool, till multiple
    • G05B2219/49007—Making, forming 3-D object, model, surface

Definitions

  • the present application relates to related technologies of intelligent control and computer vision, and studies a multi-degree of freedom 3D printing device and process. Specifically, it involves multi-degree-of-freedom 3D printing hardware platform construction, stereo model segmentation, industrial camera feedback on printing rotation, and print path planning, so that any complex three-dimensional model can be printed by using as little external support as possible.
  • 3D printer was born in the mid-1980s and was first invented by American scientists.
  • 3D printer refers to a device that uses 3D printing technology to produce real three-dimensional objects.
  • the basic principle is to use special consumables (glue, resin or powder, etc.) according to a three-dimensional model pre-designed by computer, through the deposition of adhesive. Each layer of powder is bonded and finally printed out of a 3D solid.
  • FDM Fused Deposition Modeling
  • LOM Laminated Object Manufacturing
  • SLS Selective Laser Sintering
  • 3DP Three-Dimensional Printing
  • FDM appeared in the middle and late 1980s.
  • Scott Crump the second year of Cotec Krump registered the technology as a patent, and established Stratasys, becoming one of the most famous companies in the field of 3D printing.
  • the principle of FDM technology is to heat melt the hot meltable plastic wire (usually ABS and PLA plastic). Under the control of the computer, the extruder selectively squeezes the material in the molten state to work according to the planned path of the slice. On the stage, each layer of sliced surface is lifted up to a height.
  • the current FDM process is widely used in automobiles, aerospace, household appliances, power tools, and colleges because of its simple construction principle and simple operation, low maintenance cost, safe system operation, and many optional materials and large printing width. , mold manufacturing, toy manufacturing, hand design, construction and other fields. It has even been promoted for home 3D printers, so there is a huge market demand.
  • the current 3D printers use a single-directional layer stacking technology, which can only print in a single direction of the model, which makes printing of some geometric shapes difficult to process, and even needs to divide the model into several pieces and print them separately for assembly. This obviously affects the integrity of the model and even performance.
  • many models do not have unidirectional direct printability, which requires printing the support structure to the model in front of 3D printing.
  • the support structure in the same direction causes the pole of the printed material.
  • the model-printable support structure needs to be removed after the model is successfully printed, which will affect the surface smoothness of the printed product and thus affect the product quality.
  • This application intends to study a multi-degree-of-freedom 3D printing method and apparatus based on multi-axis mechanical system and visual monitoring.
  • the FDM (Fused Deposition Modeling) 3D printing method and device are taken as an example, and the model is automatically segmented and pathd. Planning technology to achieve multi-layer stacking of 3D printing, to achieve the "free" printing of the model to the greatest extent, and to join the visual monitoring system to monitor the real-time printing.
  • an embodiment of the present application provides a multi-degree-of-freedom 3D printing apparatus, including a printing mechanism, a rotatable worktable, a visual inspection mechanism, and a control device; wherein the printing mechanism includes a print head, The rotary table includes a work surface, the print head being adapted to perform printing on the work surface, the printing mechanism and the rotatable work table combined to have at least three degrees of freedom of movement in different directions, the rotatable The table has at least two degrees of freedom of rotation with respect to different directions; the visual inspection mechanism includes a camera mounted to move integrally with the printhead; the control device is configured to three-dimensional to be printed The model is divided into a plurality of modules, and the orientation of the base plane of the module to be printed provided on the printed module on the rotatable table is monitored by the camera before printing each module (ie, monitoring the rotation of the table) Controlling the rotation of the rotatable table to position the base plane of the module to be printed suitable for printing by the
  • the printing mechanism comprises a vertical moving motor assembly and a first horizontal moving motor assembly, the vertical moving motor assembly driving the print head movement in a vertical direction, the first horizontal movement
  • the motor assembly drives the printhead movement in a first horizontal direction that is perpendicular to a vertical direction
  • the rotatable table includes a second horizontal moving motor assembly, a first rotating electrical component, and a second rotating electrical component, the The two-level moving motor assembly drives the work surface movement in a second horizontal direction perpendicular to the vertical direction and the first horizontal direction, the first rotating electrical machine assembly driving the work surface around a vertical axis of rotation Rotating, the second rotating electrical machine assembly drives the work surface to rotate about a horizontal axis of rotation.
  • the first rotating electrical machine assembly, the second rotating electrical machine assembly and the work surface are disposed at an output of the second horizontal moving motor assembly and are driven by the second horizontal moving motor assembly; a second rotating electrical machine assembly and a work surface disposed at an output of the first rotating electrical machine assembly and driven by the first rotating electrical machine assembly; the working surface disposed at an output of the second rotating electrical machine assembly and The second rotating electrical machine assembly is driven.
  • the horizontal axis of rotation extends in the first horizontal direction in a state where the first rotating electrical machine assembly does not drive the second rotating electrical machine assembly and the work surface is rotated.
  • control device compares the monitoring image of the camera with the base plane of the module to be printed to determine whether the base plane of the module to be printed has reached an orientation suitable for printing by the printhead.
  • the orientation suitable for printing by the printhead satisfies the condition that the base plane of the module to be printed is horizontal and the normal vector of the base plane is vertically upward.
  • the orientation suitable for printing by the print head further satisfies the following condition: the angle between the print head and the base plane of the module and the right angle during the printing process of each module The difference between them is not greater than the set limit value.
  • the orientation suitable for printing by the print head further satisfies the condition that the center of gravity of the module to be printed falls vertically in the base plane in the vertical direction in the base plane Within the contour, preferably at or near the geometric center of the base plane.
  • control device is arranged such that each of the divided modules supports printing only by the printed module with the same angle between the print head and the work surface, while Determine the order in which each module is printed.
  • the camera comprises a single camera which can be arranged on one side of the first horizontal direction of the print head, the control device performing binocular by constructing a pseudo binocular stereo vision system with a monocular camera
  • the measurement mode determines the angular change of the base plane of the module to be printed.
  • the camera comprises a pair of cameras arranged for the printing Both sides of the head, for example, are disposed on both sides of the first horizontal direction of the print head, and the control means determines the angle change of the base plane of the module to be printed by binocular stereoscopic measurement based on the parallax of the pair of cameras.
  • the control device is configured to divide the three-dimensional model to be printed in the following manner: obtain a skeleton of the three-dimensional model, calculate a shape diameter metric value of the point point set corresponding to the skeleton point; and perform the input three-dimensional model Model surface segmentation, wherein the shape diameter metric is used as an adjustment factor in segmentation; the input 3D model is initially divided into a plurality of modules based on the boundary of the model surface segmentation; the first printed module is selected, according to the module The connection order determines the printing order of other modules; the preliminary division of multiple modules is precisely divided so that the dividing plane between adjacent modules becomes a printable plane.
  • control device is configured to adjust a plurality of modules divided according to a boundary of the model surface segmentation, and merge the modules that do not satisfy the following conditions: the split planes between the modules cannot intersect two or two And complete the split baseband normal vector direction upwards.
  • control device is arranged to adjust the dividing plane between adjacent modules such that the angle between the print head and the tangent plane of the surface of the module to be printed during printing is not greater than a set limit value.
  • the present application in another aspect thereof, provides a multi-degree-of-freedom 3D printing method comprising the steps of: inputting a three-dimensional model to be printed; dividing a three-dimensional model to be printed into a plurality of modules; for each module, making a work surface Located in an orientation suitable for printing by the printhead such that the module is sufficiently supported by the printed module that interfaces with it during printing; the modules are sequentially printed on the work surface using the printhead.
  • the multi-degree of freedom 3D printing method of the present application is particularly suitable for implementation with the multi-degree of freedom 3D printing device described above.
  • Multi-degree of freedom 3D hitting combined with multi-axis mechanical system and visual monitoring of the embodiment of the present application The printing method and device have the following advantages:
  • FIG. 1 is a flow chart of a multi-degree of freedom 3D printing method in combination with a visual monitoring of a multi-axis mechanical system in accordance with one possible embodiment of the present application.
  • FIG. 2 is an overall view of a multi-axis FDM printing apparatus in accordance with one possible embodiment of the present application.
  • FIG. 3 is a detailed view of a visual inspection and printing mechanism of a multi-axis FDM printing device.
  • FIG. 4 is a detailed view of a three-dimensional work table of a multi-axis FDM printing apparatus.
  • Fig. 5(a) is a camera pinhole imaging model
  • (b) is an image coordinate system
  • (c) is a checkerboard calibration template.
  • Fig. 6(a) is a schematic diagram of a binocular stereo vision system constructed by a monocular camera, and (b) is a binocular stereoscopic imaging model.
  • Figure 7 is the system world coordinate system.
  • Figure 8 is a flow chart of model segmentation.
  • Fig. 9(a) is an original view of the input three-dimensional model
  • (b) is a three-dimensional model skeleton diagram
  • (c) is a division result.
  • Figure 10 is a visual monitoring flow chart.
  • Figure 11 is an angle diagram of the rotation axis.
  • the present application provides a multi-degree-of-freedom FDM (Fused Deposition Modeling) 3D printing method and apparatus combining multi-axis mechanical system and visual monitoring, and cooperates with model automatic segmentation and path planning technology to realize 3D printing.
  • FDM Field Deposition Modeling
  • the stratified layer stacking truly realizes the "free" printing of the model, and at the same time joins the visual monitoring system to monitor the printing in real time.
  • Multi-degree-of-freedom 3D printing method and device master combined with multi-axis mechanical system and visual monitoring
  • multi-axis mechanical system and visual monitoring On the basis of the original 3D printer, plus two rotating axes to achieve at least five degrees of freedom of movement, printing from multiple angles, to achieve as little external support as possible 3D printing; fixed a side next to the print head Industrial cameras make it easy to capture image information and provide real-time monitoring and feedback on printing.
  • FIG. 1 shows a multi-degree-of-freedom 3D printing (taking FDM 3D printing as an example) process in combination with a multi-axis mechanical system in accordance with a possible embodiment of the present application, including the following steps:
  • step S2 print initialization, performing camera calibration, performing binocular measurement (using a binocular stereo vision system, or constructing a pseudo binocular stereo vision system with a monocular camera) and the like.
  • step S3 the three-dimensional model to be printed is input.
  • step S4 the software implements model segmentation, divides the model into a plurality of modules, and determines the printing order of each module.
  • the base plane of each module and its normal vector are calculated and saved.
  • a certain module is printed on the workbench.
  • Gcode also known as G code, a command in the NC program
  • Cura a smart front-end display, resizing, slicing, and printing software
  • each module can be printed by the FDM 3D printer without external support when the angle between the print head (for example, the extrusion print head) and the countertop (platform) is constant.
  • step S6 it is judged whether or not the current module is printed. If not, the process returns to step S5 to continue printing, and if the printing of the current block is completed, the process proceeds to step S7.
  • step S7 it is judged whether all the modules have been printed, if all the modules have been printed, the process goes to step S8, and if all the modules have not been printed, the process goes to step S9.
  • step S8 the entire printing process ends.
  • step S9 the mechanical system is rotated by the software to move the work surface to the position of the next target plane, and then, go to step S10.
  • step S10 the industrial camera monitors the rotation process of the base plane of the module to be printed provided on the printed module. If it is not rotated, the process proceeds to step S9; after the rotation is in place, the process goes to step S5 to determine according to the previously determined printing sequence. The next module to be printed, load the Gcode of the next module, continue printing until the model is printed.
  • the module (possibly one or more) is a module that prints on the work surface at an initial horizontal position without external support.
  • step S4 when the model is divided in step S4, the factor of platform rotation is taken into account, wherein the entire model part that completes printing without external support is divided into the same module without the need of platform rotation.
  • the work surface is rotated into position so that the module to be printed can be sufficiently supported by the printed module (possibly one or more) that interfaces with it, for example, the base plane of the module to be printed At a general level.
  • the center of gravity of the module to be printed lies within the outer contour of the interface in the vertical direction in the base plane of the module to be printed, preferably at or near the geometric center of the interface.
  • each module to be printed has its base plane, which is the plane area where the module starts printing, that is, the interface between the module to be printed and the printed module.
  • a base plane is understood to be a defined area with an outer contour.
  • a multi-degree-of-freedom 3D printing device for example, an FDM 3D printing device
  • a visual monitoring provided by the present application
  • FIG. 2 is capable of performing the above printing process, mainly including: visual inspection and printing.
  • the visual inspection and printing mechanism 1100 cooperates with the Y ⁇ 1 ⁇ 2 three-dimensional work table 1200 to realize five-degree-of-freedom printing.
  • the control device 1300 is connected to the visual inspection and printing mechanism 1100, the Y ⁇ 1 ⁇ 2 three-dimensional work table 1200 by a suitable line, and controls the operations of both.
  • the visual inspection and printing mechanism 1100, the Y ⁇ 1 ⁇ 2 three-dimensional work table 1200, and the control device 1300 are preferably supported by the same rack or may be mounted on respective racks.
  • Various electrical control devices and electronically controlled mounting plates for the printing unit can be mounted inside the rack.
  • the visual inspection and printing mechanism 1100 mainly includes a visual inspection structure and a printing structure.
  • the visual inspection structure mainly includes an up and down moving motor assembly, a left and right moving motor assembly, and an industrial camera.
  • the printing structure mainly includes a print head (for example, extrusion). Print head).
  • the visual inspection and printing mechanism 1100 mainly implements control of the camera, the left and right movement of the print head, and the print control of the print head.
  • the up and down moving motor components mainly include: up and down control motor 1101, right angle reducer 1102, upper and lower motor scale 1103; left and right moving motor components mainly include: The motor 1104 and the left and right motor scales 1108 are controlled to the left and right; the industrial camera mainly includes a CCD camera 1105 and a camera light source 1106.
  • the printing structure mainly includes a print head 1107 with a thermistor, which works by heating and melting a heat-fusible plastic wire (generally ABS and PLA plastic) while heating the work surface (platform) 1203 (see Fig. 4). Set the temperature, and then the print head is under the control of the computer, according to the planned path of the slice, the material in the molten state is selectively pressed onto the work surface, and each layer of the sliced surface is lifted up to a height.
  • a print head 1107 with a thermistor which works by heating and melting a heat-fusible plastic wire (generally ABS and PLA plastic) while heating the work surface (platform) 1203 (see Fig. 4). Set the temperature, and then the print head is under the control of the computer, according to the planned path of the slice, the material in the molten state is selectively pressed onto the work surface, and each layer of the sliced surface is lifted up to a height.
  • the up-and-down control motor 1101 and the left-right control motor 1104 cooperate to control the up, down, left, and right positions of the print head 1107.
  • the left and right control motor 1104 and the print head 1107 are mounted on the output end of the up and down control motor 1101, and the up and down control motor 1101 drives the left and right control motor 1104 and the print head 1107 to move up and down; the print head 1107 is mounted on the output end of the left and right control motor 1104, left and right.
  • the control motor 1104 drives the print head 1107 to move left and right.
  • the print head 1107 is vertically downward.
  • the right angle reducer 1102 is used to decelerate the output motion of the up and down control motor 1101, for example, a speed ratio of 1:5.
  • the left and right control motors 1104 can also be equipped with suitable speed reducers.
  • the upper and lower motor scales 1103 and the left and right motor scales 1108 are used to monitor the up, down, left, and right movement of the print head 1107.
  • the CCD camera 1105 and camera light source 1106 move with the printhead 1107, i.e., their position relative to the printhead 1107.
  • the CCD camera 1105 can be fixed next to the printhead 1107.
  • the Y ⁇ 1 ⁇ 2 three-dimensional heatable table 1200 is composed of a front and rear moving motor assembly, a horizontal rotating motor assembly, a front and rear turning motor assembly, and a work surface 1203, and its function is to control the horizontal rotation and flip of the working surface 1203.
  • the base plane of any module after dividing the 3D printing model is perpendicular to the print head, and the movement is performed before and after.
  • Work surface 1203 is generally disposed below printhead 1107.
  • the front and rear turning motor assembly mainly includes a front and rear turning motor 1201 and a right angle reducer 1202; the horizontal rotating motor assembly mainly includes a horizontal rotating motor 1204 and an optional speed reducer; the front and rear moving motor components mainly include a front and rear control motor 1205, front and rear motor scales. 1206 and optional reducer.
  • the front and rear control motor 1205, the front and rear turning motor 1201 and the horizontal rotating motor 1204 cooperate to control the front and rear positions of the work surface 1203 and the front and rear and horizontal rotation angles.
  • the front and rear turning motor 1201, the horizontal rotating motor 1204, and the work surface 1203 are installed at the output end of the front and rear control motor 1205, and the front and rear control motor 1205 drives the front and rear turning motor 1201 and the horizontal rotating motor.
  • the front and rear turning motor 1201 and the work surface 1203 move back and forth;
  • the front and rear turning motor 1201 and the work surface 1203 are installed at the output end of the horizontal rotary motor 1204, and the horizontal rotary motor 1204 controls the front and rear turning motor 1201 and the work surface 1203 to rotate about a vertical rotation axis;
  • the visual inspection and printing mechanism 1100 and the Y ⁇ 1 ⁇ 2 three-dimensional work table 1200 form a five-degree-of-freedom mechanical system.
  • the control device 1300 mainly includes: an image capture card 1310 connected to the CCD camera 1105 and the camera light source 1106; a display 1320; a motor drive component 1330 for controlling the operation of each of the aforementioned motors; and a CAN card (Controller Area Network)
  • the controller area network 1340 can be used for communication between serial ports, can be connected to the image capture card 1310 or separately and connected to the host computer 1360; a power supply 1350 for powering the various components of the control device 1300.
  • the image capture card 1310 can be integrated into the host computer 1360 or separately and connected to the host computer 1360.
  • the motor drive assembly 1330 can be configured as a separate circuit board that can be integrated into the host computer 1360 or connected to the host computer 1360.
  • the power source 1350 can be an additional power source that is independent of the host computer 1360.
  • the present application also provides a multi-degree of freedom 3D printing method that combines a multi-axis mechanical system capable of implementing the above-described printing flow with visual monitoring.
  • a printing method (exemplified by a multi-degree-of-freedom FDM3D printing method) which can be realized by the printing apparatus described above or a printing apparatus having a similar function, which includes the following steps, is described below:
  • print initialization operation mainly including camera calibration, binocular stereo vision system or monocular camera to construct a pseudo binocular stereo vision system for binocular measurement
  • This application incorporates a visual monitoring device (JAI's camera sp-20000c-pmcl and PENTAX's optical lens YF5028) to visually monitor the rotating plane.
  • the industrial camera is fixed next to the printhead and mainly monitors two messages: monitoring the printed module. Look down the contour to determine if the table is spinning and if the rotation is in place.
  • step S200 (can be regarded as a feasible embodiment of step S4 described above), and divides the input three-dimensional model.
  • This function is mainly established on the FDM printing mechanism and the Y ⁇ 1 ⁇ 2 three-dimensional work table, and the corresponding control is performed.
  • the interface controls it to ensure that each part after the division can be printed without external support when the angle between the print head and the work surface is unchanged, and the model segmentation result is obtained, and the order of printing of each part is determined.
  • S300 (can be regarded as a feasible embodiment of some of the steps S5, S9, S10 described above), software control mechanical system, this function is mainly established in the visual inspection and FDM printing mechanism, Y ⁇ 1 ⁇ 2 three-dimensional workbench
  • the above is controlled by the corresponding control interface, and the model is printed according to the segmentation result and the printing sequence of step S200, and each block is regarded as being able to print without external support when the angle between the print head and the work surface is constant.
  • the module mainly involves the linkage between different mechanical structures to match the printing problem and the control of the Gcode generated before the completion of the printing of the print head (for example, extrusion) of the print position at different print positions.
  • step S100 comprises the following sub-steps:
  • the world coordinate system is projected onto the two-dimensional plane through the projection model and needs to be transformed by the three-dimensional camera coordinate system, where O
  • the point is the camera's optical center (projection center)
  • the X c axis and the Y c axis are parallel to the x and y axes of the imaging plane coordinate system
  • the Z c axis is the optical axis of the camera, perpendicular to the image plane.
  • the intersection of the optical axis and the image plane is the main point O 1 of the image
  • the coordinate system OX c Y c Z c is called the coordinate system of the camera
  • OO 1 is the focal length f of the camera
  • the coordinate system O w -X w Y w Z w is The world coordinate system, with the translation vector t and the rotation matrix R can be used to represent the relationship between the camera coordinate system and the world coordinate system.
  • the world coordinate system has the following relationship with the camera coordinate system:
  • the unit is a physical unit, not a common image unit pixel. Therefore, it is necessary to construct an image coordinate system O 0 -uv in units of pixels, where the x axis is parallel to the u axis, and the y axis is parallel to the v axis. , as shown in the image coordinate system of Figure 5 (b).
  • O 1 -xy and OX c Y c Z c have the following relationship:
  • A is called the inner parameter matrix
  • P is called the outer parameter matrix
  • fx and f y are the normalized focal lengths on the u-axis and the v-axis, respectively.
  • the task of camera calibration is to request these two matrices.
  • This application uses the checkerboard calibration method for calibration.
  • the main process of this method is as follows: print a template and paste it on a plane.
  • the template captures several template images from different angles and detects the image.
  • the internal and external parameters of the camera are obtained from the world coordinates and image coordinates of the feature point.
  • binocular stereo vision is based on parallax.
  • the three-dimensional information is acquired by the principle of trigonometry.
  • the image is captured by two cameras to form a triangle between the image plane and the target.
  • the present application includes the use of a pair of industrial cameras on both sides of the print head to achieve binocular stereo vision measurement shape.
  • the binocular stereo vision measurement will be realized based on the monocular camera, and the pseudo-binocular stereo is constructed with the monocular camera.
  • the vision system performs binocular measurements as shown in Figure 6(a).
  • Determining a plane according to three points that are not collinear measuring the world coordinates of the three marker points at the mark on the work surface, and simultaneously picking three points of the mark position on the image, and calculating the coordinate transformation of the points in the image according to the three sets of points A transformation matrix that conforms to the world coordinates of the actual position of the work surface.
  • the camera is panned, the captured image is taken on the work surface with three marks, and the boundary pixel points in the image are obtained.
  • the three-dimensional coordinate of the mark is calculated by the binocular stereo vision system, and the world coordinates corresponding to the actual mark point are measured; further According to the conversion formula of two three-dimensional coordinate systems, the transformation matrix between the image coordinates and the actual three-dimensional coordinates captured by the camera is obtained; finally, the coordinates of the entire image are multiplied by the transformation matrix to obtain the actual world coordinates of the work surface.
  • the right camera can establish the same equation according to the above formula, and the variable is the corresponding right camera variable.
  • a binocular stereo vision system is constructed with a monocular camera.
  • the two cameras have the same focal length f, which is obtained by binocular correction according to the SGBM stereo matching algorithm.
  • the rotation matrix is about the unit matrix. Therefore, in this system, the two cameras default to a parallel relationship, thereby deforming the above equation into:
  • the present application takes the intersection of the horizontal rotation axis and the vertical rotation axis as the origin, the front and rear translation axes as the z axis, the visual module up and down translation axis as the y axis, and the left and right translation axes as the x axis, such as The system world coordinate system shown in the table top 1203 in Fig. 7 is shown.
  • [Tx Ty Tz] T is the translation vector between the world coordinate system and the camera coordinate system.
  • the translation vector is solved by determining the initial position of the camera, and the initial position of the camera is taken as the unique camera coordinate system of the system, that is, all the coordinates obtained by the binocular system are first converted into coordinates in the initial position camera coordinates before the next calculation can be performed.
  • step S200 comprises the following sub-steps as shown in Figure 8:
  • the input model is mesh-divided, and then the closed mesh is simplified to reduce the amount of data of the model, and the model is contracted by the Laplacian mesh compaction method until the collapse is a skeleton, wherein Laplac is based on
  • the mesh shrinkage requires repeated iterative Laplace equations until the mesh model shrinks into a skeleton, as follows: the implicit Laplace equation:
  • W L represents the diagonal contraction force matrix
  • W H is the diagonal attraction matrix
  • the i-th element is W L , i (W H, i )
  • FIG. 9(a) the original three-dimensional model is shown, and (b) is a three-dimensional model skeleton.
  • S230 obtaining a segmentation plane of the model by a boundary segmentation of the model surface, and roughly dividing the input three-dimensional model into several modules according to the segmentation plane.
  • each module manually select the first printed module, the base plane of the first module should be horizontal Plane, according to the order of connection between the modules to determine the printing order of other modules, each module can print without the external support when the angle between the print head and the work surface is unchanged, which requires the surface of each module It is a safe surface.
  • a max is the maximum angle between the print head and the tangent plane of the model surface in the case where the model can be printed without external support.
  • step S300 comprises the following sub-steps as shown in FIG. 10:
  • step S310 the printing order of each module is printed, and each block is regarded as a module that can be printed without external support printing when the angle between the print head and the work surface is unchanged, so that printing of each module is easy to implement.
  • the present application generates the Gcode of each module in sequence by parsing the previously generated splitting module and the printing order, and loads the Gcode of the loading module to print, and each module completes a module, and the program jumps out of the current module. Gcode.
  • V' is a vector in which V is rotated to the YOZ plane
  • ⁇ is an angle at which the vector V' is rotated about the X-axis such that the vector V rotates in parallel with the Y-axis.
  • the vector V' and the Y axis are simultaneously on the plane YOZ, so ⁇ is the angle between the vector V' and the Y axis.
  • a vector can be represented by two angles ⁇ and ⁇ , so that ⁇ 1 and ⁇ 1 represent the normal vector of the current position of the work surface, and ⁇ 2 and ⁇ 2 represent the normal vector of the target position of the work surface, and the following formula is given:
  • ⁇ 3 and ⁇ 3 can represent the angle of rotation.
  • the image is equalized by the color histogram, and then the color histogram is equalized.
  • the image is binarized, and the image R channel value is greater than the B channel and the G channel value by 2 times as the constraint condition, ie
  • the contour image is extracted from the binarized image, and the corner point corresponding to the position is obtained as the marker point according to the position of the contour in the figure, for example, the upper corner point of the contour is obtained in the upper contour, for example, the lower left corner is obtained at the lower left.
  • the corner point is obtained by transforming the matrix to find the coordinates of the marker point in the world coordinate system.
  • the plane of the work surface and its normal vector are obtained.
  • the three points on the guide and the plane formed by the three points on the model are respectively obtained. vector.
  • the coordinates of the three non-collinear points on the model are (x 1 , y 1 , z 1 ), (x 2 , y 2 , z 2 ), (x 3 , y 3 , z 3 ), then according to the plane equation point French, let the plane equation be:
  • the in-point coordinate solution coefficients A, B, and C are:
  • the control workbench drives the printed module to rotate together: after printing the current module, we know the current position of the workbench and its normal vector ⁇ 1 , ⁇ 1 ; during the printing process, we control the 3D model Synchronize with the change of the printing process, and then transfer the 3D model to the target position (the base plane normal vector of the module to be printed provided on the printed module is vertically upward), and calculate the position of the table position (ie, the target position) at this time and the method thereof.
  • the vectors ⁇ 2 and ⁇ 2 calculate the rotation angle and then the rotation first rotation control.
  • the rotation process needs to be visually monitored.
  • the industrial camera mainly monitors the printing plane visually. Therefore, our program only needs to collect a picture after completing the control table rotation, and analyze the picture to obtain the top view of the printed part.
  • the minimum circumscribed rectangle of the contour is calculated and the aspect ratio of the rectangle is calculated; at the same time, the top view of the 3D model synchronized with the printing process is calculated, and the minimum circumscribed rectangle is obtained and the aspect ratio of the rectangle is calculated. If the minimum circumscribed rectangle aspect ratio of the top view of the printed portion is approximately equal to the minimum circumscribed rectangle aspect ratio of the 3D model's top view contour synchronized to the printing process, we consider the rotation in place if the error tolerance is exceeded. , repeat the above steps until it is rotated into place.
  • the Gcode of the next module is read for printing, and so on, until all the modules are printed.
  • the multi-degree-of-freedom 3D printing method and apparatus combining the multi-axis mechanical system of the embodiment of the present application and visual monitoring has the following advantages:
  • the printing apparatus and method described above are merely specific embodiments capable of implementing the present application. Various modifications to these embodiments can be made by those skilled in the art in the light of the concept of the present application.
  • the printing apparatus of the present application may broadly include at least five degrees of freedom (three degrees of freedom and two degrees of freedom) consisting of a printing mechanism (including but not limited to an FDM printing mechanism) and a rotatable table. a mechanical system in which the rotatable table has rotational degrees of freedom with respect to two spatial orthogonal directions, and the degree of freedom of movement along three spatial orthogonal directions can be distributed between the FDM printing mechanism and the rotatable table as needed .
  • At least five degrees of freedom of the mechanical system of the present application are distributed in such a manner that the printing mechanism has only freedom of movement without rotational freedom, and the table has rotational freedom and possible freedom of movement.
  • the print head is always in a vertically downward orientation, which easily ensures the positioning accuracy of the print head.
  • the print head is an extrusion type print head.
  • the present application is equally applicable to other forms of printheads.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Optics & Photonics (AREA)
  • Robotics (AREA)
  • Human Computer Interaction (AREA)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)

Abstract

一种多自由度3D打印装置包括打印机构、可转动工作台（1200）、视觉检测机构和控制装置（1300），打印机构包括打印头（1107），工作台（1200）包括工作台面（1203），打印机构和工作台（1200）组合起来具有三个移动自由度，工作台（1200）具有两个转动自由度；视觉检测机构包括相机，安装成与打印头（1107）一体地移动，用于监视工作台的角度；控制装置（1300）将待打印的三维模型分割为多个模块，并且在打印每个模块之前，控制工作台（1200）以使工作台面（1203）位于适合被打印头实施打印的方位，尽可能的使得模块在打印过程中受到与其交界的已打印模块的充分支撑，而无需额外的外界支撑。

Description

多轴机械系统与视觉监视相结合的3D打印方法与装置 技术领域
本申请涉及智能控制及计算机视觉的相关技术，研究多自由度的3D打印装置及工艺。具体涉及多自由度3D打印硬件平台搭建，立体模型分割，工业相机对打印旋转的反馈，打印路径规划，从而能将任何复杂的三维模型通过使用尽可能少的外界支撑的方式打印出来。
背景技术
3D打印机诞生于20世纪80年代中期，是由美国科学家最早发明的。3D打印机是指利用3D打印技术生产出真实三维物体的一种设备，其基本原理是利用特殊的耗材(胶水、树脂或粉末等)按照由电脑预先设计好的三维立体模型，通过黏结剂的沉积将每层粉末黏结成型，最终打印出3D实体。
随着3D打印技术迅速发展，近年来市面上出现了多种不同类型的3D打印成型技术，如熔融堆积成型技术(Fused Deposition Modeling,FDM)、叠层实体制造(Laminated Object Manufacturing,LOM)、选择性激光烧结(Selective Laser Sintering,SLS)、三维粉末粘接(Three-Dimensional Printing,3DP)、光固化3D打印技术等等，这些技术各有特点，以满足不同应用领域的应用需求。其中FDM出现在20世纪80年代中后期。1988年由Scott Crump发明，第二年科特克鲁姆普将该技术注册为专利，并成立了Stratasys公司，成为3D打印领域最著名的公司之一。FDM技术原理是将可热熔的塑料丝(一般是ABS和PLA塑料)加热融化，挤出机在计算机的控制下，根据切片的规划路径，将熔融状态下的材料选择性地挤压到工作台上，每挤满一层的切片面，就抬升一层高度。目前的FDM工艺，因其构造原理和操作简单，维护成本低，系统运行安全，以及可选材料多，打印幅面大，所以现在被广泛应用于汽车、航空航天、家用电器、电动工具、院校、模具制造、玩具制造、手版设计、建筑等领域。甚至被推广用于家用3D打印机，因此有庞大的市场需求。
目前的3D打印机都采用单方向层式堆叠技术，即只能沿着模型的单一方向进行打印，这就使得有些几何形状的打印很难处理，甚至需要将模型分割成若干块分别打印后进行组装，这显然影响模型的完整性甚至 性能。另一方面，实际打印过程中发现，很多模型都不具有单方向直接可打印性，这就需要在3D打印前面向模型可打印加支撑结构，一方面同方向的支撑结构引起了打印材料的极大浪费，另一方面面向模型可打印的支持结构在模型打印成功后都需要去除，这将影响打印产品的表面光滑度，进而影响产品质量。
发明内容
本申请拟研究基于多轴机械系统与视觉监视相结合的多自由度3D打印方法与装置，以FDM(Fused Deposition Modeling,熔融堆积成型技术)3D打印方法与装置为例，配合模型自动分割和路径规划技术，实现3D打印的多个方向层式堆叠，最大程度上实现模型的“自由”打印，同时加入视觉监视系统，对打印进行实时监控。
为解决上述技术问题，本申请实施例提供了一种多自由度3D打印装置，包括打印机构、可转动工作台、视觉检测机构和控制装置；其中，所述打印机构包括打印头，所述可转动工作台包括工作台面，所述打印头适于在所述工作台面上进行打印，所述打印机构和可转动工作台组合起来具有至少三个在不同方向上的移动自由度，所述可转动工作台具有至少两个相对于不同方向的转动自由度；所述视觉检测机构包括相机，所述相机被安装成与所述打印头一体地移动；所述控制装置被设置成将待打印的三维模型分割为多个模块，并且在打印每个模块之前，通过所述相机监视所述可转动工作台上的已打印模块上提供的待打印模块基平面的方位(也即监视工作台的旋转情况)，由此控制所述可转动工作台转动以使待打印模块基平面位于适合被所述打印头实施打印的方位，使得模块在打印过程中受到已打印模块的充分支撑(除了第一个打印的模块由工作台支撑外)。
根据一种可行实施方式，所述打印机构包括竖直移动电机组件和第一水平移动电机组件，所述竖直移动电机组件沿着竖直方向驱动所述打印头移动，所述第一水平移动电机组件沿着与竖直方向垂直的第一水平方向驱动所述打印头移动；所述可转动工作台包括第二水平移动电机组件、第一旋转电机组件和第二旋转电机组件，所述第二水平移动电机组件沿着与竖直方向和第一水平方向垂直的第二水平方向驱动所述工作台面移动，所述第一旋转电机组件驱动所述工作台面绕一条竖直旋转轴线 旋转，所述第二旋转电机组件驱动所述工作台面绕一条水平旋转轴线转动。
根据一种可行实施方式，所述第一旋转电机组件、第二旋转电机组件和工作台面设置在所述第二水平移动电机组件的输出端并且由所述第二水平移动电机组件驱动；所述第二旋转电机组件和工作台面设置在所述第一旋转电机组件的输出端并且由所述第一旋转电机组件驱动；所述工作台面设置在所述第二旋转电机组件的输出端，并由所述第二旋转电机组件驱动。
根据一种可行实施方式，在所述第一旋转电机组件未驱动第二旋转电机组件和工作台面旋转的状态下，所述水平旋转轴线沿所述第一水平方向延伸。
根据一种可行实施方式，所述控制装置将所述相机的监视图像与待打印模块基平面相比较而确定待打印模块基平面是否已到达适合被所述打印头实施打印的方位。
根据一种可行实施方式，所述适合被所述打印头实施打印的方位满足下述条件：待打印模块的基平面处于水平，并且所述基平面的法向量竖直向上。
根据一种可行实施方式，所述适合被所述打印头实施打印的方位还满足下述条件：在每个模块的打印过程中，打印头与该模块的基平面之间的夹角与直角之间的差值不大于设定的极限值。
根据一种可行实施方式，所述适合被所述打印头实施打印的方位还满足下述条件：待打印模块的重心在所述基平面中的竖直方向垂足落在所述基平面的外轮廓线内，优选位于所述基平面的几何中心处或附近。
根据一种可行实施方式，所述控制装置被设置成使每个分割出的模块在所述打印头和所述工作台面之间夹角不变的情况下仅由已打印模块支撑着打印，同时确定每一模块打印的顺序。
根据一种可行实施方式，所述相机包括单一的相机，其可以布置在所述打印头的第一水平方向一侧，所述控制装置通过以单目相机构建伪双目立体视觉系统进行双目测量方式确定待打印模块基平面的角度变化。
根据一种可行实施方式，所述相机包括一对相机，布置在所述打印 头的两侧，例如布置在所述打印头的第一水平方向两侧，所述控制装置基于所述一对相机的视差通过双目立体视觉测量方式确定待打印模块基平面的角度变化。
根据一种可行实施方式，所述控制装置被设置成以如下方式分割待打印的三维模型：得到三维模型的骨架，计算出骨架点对应曲面点集的形状直径度量值；将输入的三维模型进行模型表面分割，其中所述形状直径度量值被用作分割时的调整因素；基于模型表面分割的边界将输入的三维模型初步划分成多个模块；选择第一个打印的模块，根据模块之间的连接顺序确定其他模块的打印顺序；对初步划分的多个模块进行精确划分，使相邻模块之间的分割平面变为可打印的平面。
根据一种可行实施方式，所述控制装置被设置成对基于模型表面分割的边界划分出的多个模块进行调整，对不满足下述条件的模块进行合并：模块间的分割平面不可两两相交、并且完成分割后的所有模块基平面法向量方向向上。
根据一种可行实施方式，所述控制装置被设置成对相邻模块之间的分割平面进行调整，使得打印时打印头与待打印模块表面的切平面之间的夹角不大于设定的极限值。
本申请在其另一方面提供了一种多自由度3D打印方法，包括下述步骤：输入待打印的三维模型；将待打印的三维模型分割为多个模块；对于每个模块，使工作台面位于适合被打印头实施打印的方位，以使得模块在打印过程中受到与其交界的已打印模块的充分支撑；利用打印头在所述工作台面上顺序打印出各模块。。
本申请的多自由度3D打印方法尤其适合于利用前面描述的多自由度3D打印装置实施。
因此，前面针对多自由度3D打印装置描述的各项特征，同样适合于本申请的多自由度3D打印方法。
需要指出，本申请的打印装置和方法在应用于复杂形状的模型时，模型的某些部位可能不能完全满足前面描述的条件，例如存在较大悬垂部位，不可避免地需要对这些部位加支撑进行打印。尽管如此，本申请仍能实现对模型的主体部分进行无外界支撑的打印。
本申请实施例的多轴机械系统与视觉监视相结合的多自由度3D打 印方法与装置具有如下优点：
1)节约打印材料，节省人工去除支撑的时间；
2)可打印性，此多轴3D打印的方法，可以以最少的外界支撑的打印出任何复杂模型，适用性强。因此，本申请具有一定的应用价值和意义。
附图说明
图1是根据本申请的一种可行实施方式的多轴机械系统与视觉监视相结合的多自由度3D打印方法的流程图。
图2是根据本申请的一种可行实施方式的多轴FDM打印装置的整体图。
图3是多轴FDM打印装置的视觉检测和打印机构的细节图。
图4是多轴FDM打印装置的三维度工作台的细节图。
图5(a)是相机针孔成像模型，(b)是图像坐标系，(c)是棋盘格标定模板。
图6(a)是单目相机构建双目立体视觉系统示意图，(b)是双目立体成像模型。
图7是系统世界坐标系。
图8是模型分割流程图。
图9(a)是输入的三维模型原图，(b)是三维模型骨架图，(c)是分割结果。
图10是视觉监控流程图。
图11是旋转轴角度图。
具体实施方式
下文中将结合附图对本申请的实施例进行详细说明，需要说明的是，在不冲突的情况下，本申请中的打印装置和方法适用于任何复杂的三维模型。
本申请提供了一种多轴机械系统与视觉监视相结合的多自由度FDM(Fused Deposition Modeling,熔融堆积成型技术)3D打印方法与装置，配合模型自动分割和路径规划技术，实现3D打印的多个方向层式堆叠，真正实现模型的“自由”打印，同时加入视觉监视系统，对打印进行实时监控。
多轴机械系统与视觉监视相结合的多自由度3D打印方法与装置主 要在原有的3D打印机的基础上，加上两个旋转轴实现至少五个自由度的运动，从多个角度进行打印，从而实现尽可能少的外界支撑的3D打印；在打印头旁边固定一个工业相机，方便采集图像信息，对打印进行实时监测反馈。
图1显示了根据本申请一种可行实施方式的多轴机械系统与视觉监视相结合的多自由度3D打印(以FDM 3D打印为例)流程，包括下述步骤：
在步骤S1：开始。
在步骤S2：打印初始化，进行相机标定、进行双目测量(采用双目立体视觉系统、或以单目相机构建伪双目立体视觉系统)等初始化操作。
在步骤S3：输入待打印的三维模型。
在步骤S4：软件实现模型分割，将模型分割为多个模块，确定各模块的打印顺序。在这个步骤中，计算并保存每一模块的基平面及其法向量。
在步骤S5：在工作台上打印某个模块。通过Cura(一款智能的前端显示、调整大小、切片和打印软件)生成Gcode(又称为G代码，是数控程序中的指令)，然后由打印头和工作台配合，逐层进行打印。通过这个步骤，每一模块可以由FDM 3D打印机在打印头(例如挤出式打印头)和工作台面(平台)夹角不变的情况下无外界支撑的打印出来。
在步骤S6：判断是否打印完当前模块，如果没有打印完，则返回步骤S5继续打印，如果完成当前块的打印，则转到步骤S7。
在步骤S7：判断是否已打印完所有模块，如果已打印完所有模块，则转到步骤S8，如果没有打印完所有模块，则转到步骤S9。
在步骤S8：整个打印程序结束。
在步骤S9：由软件控制机械系统将工作台面旋转到下一目标平面的位置，然后，转到步骤S10。
在步骤S10：由工业相机监测已打印模块上提供的待打印模块基平面的旋转过程，若未旋转到位，则继续执行步骤S9；旋转到位后，转到步骤S5，按照前面确定的打印顺序确定下一个将要打印的模块，载入下一模块的Gcode，继续进行打印，直到模型打印完成。
需要指出，在步骤S4确定各模块的打印顺序时，确定出的首次打印 模块(可能是一或多个)是工作台面处在初始水平位置即可无外界支撑地打印的模块。
此外，在步骤S4中对模型分割时，计入平台旋转的因素，其中，将不需要平台旋转即可无外界支撑地完成打印的整个模型部位划分为同一个模块。
在步骤S9的工作台面旋转过程中，工作台面被旋转到位，使得待打印的模块能够被与其交界的已打印模块(可能是一个或多个)充分地支撑，例如，使得待打印模块的基平面处于大体水平向上。此外，待打印模块的重心在待打印模块的基平面中的竖直方向垂足位于该界面的外轮廓线内，优选位于该界面的几何中心处或附近。这样，在打印一个模块时，该模块受到已打印模块的支撑，而不需为被打印的模块提供额外的支撑结构。
这里需要指出，每个待打印模块都有其基平面，该基平面是模块起始打印的平面区域，也即待打印模块与已打印模块之间的分界面。基平面应理解为具有外轮廓的限定区域。
可以理解，上述打印流程可以以各种适宜的方式实现。下面参照图2介绍本申请提供的一种多轴机械系统与视觉监视相结合的多自由度3D打印装置(例如，FDM 3D打印装置)，其能够执行上述打印流程，主要包括：视觉检测和打印机构1100、Yθ1θ2三维度工作台1200、控制装置1300。视觉检测和打印机构1100和Yθ1θ2三维度工作台1200协作而实现五自由度打印。控制装置1300通过适宜的线路与视觉检测和打印机构1100、Yθ1θ2三维度工作台1200连接，并且控制二者的操作。视觉检测和打印机构1100、Yθ1θ2三维度工作台1200、控制装置1300优选由同一个机架支撑，也可以安装在各自的机架上。机架内部可安装打印装置的各种电气控制器件及电控安装板。
如图3中所示，视觉检测和打印机构1100主要包括视觉检测结构和打印结构，视觉检测结构主要包括上下移动电机组件、左右移动电机组件和工业相机，打印结构主要包括打印头(例如挤出式打印头)。视觉检测和打印机构1100主要实现控制相机、打印头的左右上下移动和打印头的打印控制。其中，上下移动电机组件主要包括：上下控制电机1101、直角减速机1102、上下电机光栅尺1103；左右移动电机组件主要包括： 左右控制电机1104、左右电机光栅尺1108；工业相机主要包括：CCD相机1105、相机光源1106。
打印结构主要包括带热敏电阻的打印头1107，其工作原理为将可热熔的塑料丝(一般是ABS和PLA塑料)加热融化，同时加热工作台面(平台)1203(见图4)达到预设温度，然后打印头在计算机的控制下，根据切片的规划路径，将熔融状态下的材料选择性地挤压到工作台面上，每挤满一层的切片面，就抬升一层高度。
如图3所示，上下控制电机1101和左右控制电机1104协作而控制打印头1107的上下左右位置。例如，左右控制电机1104和打印头1107安装在上下控制电机1101的输出端，上下控制电机1101驱动左右控制电机1104和打印头1107上下移动；打印头1107安装在左右控制电机1104的输出端，左右控制电机1104驱动打印头1107左右移动。打印头1107竖直向下。
直角减速机1102用于为上下控制电机1101的输出运动减速，例如速比为1:5。左右控制电机1104也可以配备适宜的减速机。上下电机光栅尺1103、左右电机光栅尺1108用于监测打印头1107的上下左右运动。
CCD相机1105和相机光源1106与打印头1107一起运动，即它们相对于打印头1107的位置不变。例如，CCD相机1105可以固定在打印头1107旁边。
如图4所示，Yθ1θ2三维度的可加热工作台1200由前后移动电机组件、水平旋转电机组件、前后翻转电机组件和工作台面1203组成，其功能为控制工作台面1203水平旋转和翻转使3D打印模型分割后的任意模块的基平面与打印头垂直，并完成前后移动工作。工作台面1203大体布置在打印头1107下方。前后翻转电机组件主要包括前后翻转电机1201、直角减速机1202；水平旋转电机组件主要包括水平旋转电机1204以及可选的减速机；前后移动电机组件主要包括工作台前后控制电机1205、前后电机光栅尺1206以及可选的减速机。
前后控制电机1205、前后翻转电机1201和水平旋转电机1204协作而控制工作台面1203的前后位置以及前后和水平转角。例如，前后翻转电机1201、水平旋转电机1204和工作台面1203安装在前后控制电机1205的输出端，在前后控制电机1205驱动前后翻转电机1201、水平旋转电机 1204和工作台面1203前后移动；前后翻转电机1201和工作台面1203安装在水平旋转电机1204的输出端，水平旋转电机1204控制前后翻转电机1201和工作台面1203绕一条竖直旋转轴线旋转；工作台面1203安装在前后翻转电机1201的输出端，前后翻转电机1201控制工作台面1203绕一条垂直于竖直旋转轴线的水平翻转轴线前后翻转。
通过打印头1107与工作台面1203二者的位置和角度的组合，实现了五自由度打印。视觉检测和打印机构1100和Yθ1θ2三维度工作台1200中组成一个五自由度机械系统。
如图2所示，控制装置1300主要包括：与CCD相机1105、相机光源1106相连的图像采集卡1310；显示器1320；用于控制前述各电机的操作的电机驱动组件1330；CAN卡(Controller Area Network控制器局域网络)1340可用于各串口之间通信，可以与图像采集卡1310相连或单独配备并连接到主计算机1360；用于为控制装置1300的上述各部件供电的电源1350。图像采集卡1310可以集成在构成主计算机1360中，或者单独配备并连接到主计算机1360。电机驱动组件1330可以构造成单独的电路板，其可以集成在主计算机1360中或者连接到主计算机1360。电源1350可以是相对于主计算机1360独立的额外电源。
本申请还提供了一种能够实现上述打印流程的多轴机械系统与视觉监视相结合的多自由度3D打印方法。下面描述一种可以通过前面描述的打印装置或具有类似功能的打印装置实现的打印方法(以多自由度FDM3D打印方法为例)，其包括以下步骤：
S100(可以看作前面描述的步骤S2的可行实施例)、打印初始化操作，主要包括相机标定、以双目立体视觉系统或以单目相机构建伪双目立体视觉系统进行双目测量等工作，本申请加入视觉监控装置(JAI公司的相机sp-20000c-pmcl和PENTAX公司的光学镜头YF5028)对旋转平面进行视觉监控，工业相机固定在打印头旁边，主要监控两个信息：监测已打印模块的俯视轮廓，以判断工作台是否旋转以及旋转是否到位。
S200(可以看作前面描述的步骤S4的可行实施例)、对输入的三维模型进行分割，此功能主要是建立在FDM打印机构、Yθ1θ2三维度工作台上进行的，通过相应的控制接口对其进行控制，从而保证分割后的每一部分都可以在打印头和工作台面夹角不变的情况下无外界支撑的打 印，得到模型分割结果，同时确定每一部分打印的顺序。
S300(可以看作前面描述的步骤S5、S9、S10中的一些动作的可行实施例)、软件控制机械系统，此功能主要是建立在视觉检测和FDM打印机构、Yθ1θ2三维度工作台上进行的，通过相应的控制接口对其进行控制，按步骤S200的分割结果及打印顺序打印模型，将每一块看成是可在打印头和工作台面夹角不变的情况下无外界支撑打印的模块，主要涉及不同机械结构之间的联动配合打印问题和解析之前生成的Gcode完成对不同打印位置打印头打印出(例如挤出)的材料多少的控制。
根据一种可行实施方式，步骤S100包括下述子步骤：
S110、为了减少相机检测时的误差，我们拟计划先对相机进行标定，计算出工作台面上设定的标志点的实际坐标位置，也就是计算机视觉中的世界坐标，如图5(a)所示相机针孔成像模型，相机不仅有二维的图像坐标系，也存在一个三维的相机坐标系，世界坐标系经过投影模型投影到二维平面上需先经过三维相机坐标系的转换，其中O点为摄像机光心(投影中心)，Xc轴和Yc轴与成像平面坐标系的x轴和y轴平行，Zc轴为摄像机的光轴，和图像平面垂直。光轴与图像平面的交点为图像的主点O1，坐标系O-XcYcZc称为摄像机的坐标系，OO1为摄像机的焦距f，坐标系Ow-XwYwZw为世界坐标系，以平移向量t和旋转矩阵R可以用来表示相机坐标系与世界坐标系的关系，世界坐标系与相机坐标系存在如下关系：
Figure PCTCN2016111194-appb-000001
对于O1-xy坐标系，其单位是物理单位，不是常用图像单位像素，因此需要构建以像素为单位的图像坐标系O0-uv，其中x轴与u轴平行，y轴与v轴平行，如图5(b)的图像坐标系所示。假设(u0，v0)代表O1在O0-uv坐标系下的坐标，dx与dy分别表示每个像素在横轴x和纵轴y上的物理尺寸，则图像中的每个像素在O0-uv坐标系中的坐标和在O1-xy坐标系中的坐标之间都存在如下的关系：
Figure PCTCN2016111194-appb-000002
将上式转为其次坐标与矩阵可表示为：
Figure PCTCN2016111194-appb-000003
而O1-xy与O-XcYcZc存在如下关系：
Figure PCTCN2016111194-appb-000004
因此根据上面两个式子，可得到
Figure PCTCN2016111194-appb-000005
则可得图像坐标系O0-uv与世界坐标系Ow-XwYwZw之间的关系为：
Figure PCTCN2016111194-appb-000006
其中A称作内参数矩阵，P称作外参数矩阵，fx和fy分别为u轴和v轴上的归一化焦距，相机标定的任务就是要求出这两个矩阵。
本申请使用棋盘格标定法进行标定，该方法主要过程是如下：打印一张模板并贴在一个平面上，模板如图5(c)所示，从不同角度拍摄若干张模板图像并检测出图像中的特征点，根据特征点的世界坐标和图像坐标求出摄像机的内参数和外参数。
S120、双目立体视觉是基于视差，由三角法原理进行三维信息的获取，通过两个相机拍摄图像，使图像平面和目标之间构成一个三角形。本申请包含利用打印头两侧的一对工业相机实现双目立体视觉测量的情 形。此外，作为另一种可行方案，为了便于机械结构的实现，我们研究只配备一台工业相机的情况，所以进行双目立体视觉测量将基于单目相机实现，以单目相机构建伪双目立体视觉系统进行双目测量，如图6(a)所示。依据三个不共线的点确定一个平面，测量工作台面上标记处的三个标记点世界坐标，同时拾取图像上标志位置的三个点，根据这三组点求出图像中点的坐标变换到与工作台面实际位置世界坐标一致的变换矩阵。
首先平移相机，对贴有三个标记的工作台面拍摄采集图像，求出图像中标记的边界像素点；其次通过双目立体视觉系统，算出标记的三维坐标，测量实际标记点对应的世界坐标；进一步，根据两个三维坐标系的转换公式，求相机拍摄下的图像坐标和实际三维坐标之间的变换矩阵；最后，将整个图像的坐标乘以该变换矩阵得到工作台面实际的世界坐标。
进行双目立体视觉测量，如图6(b)双目立体成像模型所示，假设目标有一点P，分别在左、右两个相机上获取点P(x，y，z)的图像，记图像坐标分别为pl＝(Xl，Yl)，pr＝(Xr，Yr)。现设O-xyz为左相机坐标系，图像坐标系为O-XlYl，焦距为fl；Or-xryrzr为右相机坐标系，图像坐标系为O-XrYr，焦距为fr。通过相机透视变换模型可知：
Figure PCTCN2016111194-appb-000007
右相机可根据上式成立同样的等式，变量是相应的右相机变量。
坐标系O-xyz和Or-xryrzr之间的相互位置关系设变换矩阵Mlr，表示为：
Figure PCTCN2016111194-appb-000008
其中r1，r2，…，r9组成两个坐标系之间的旋转矩阵，(tx，ty，tz)为两者间的平移向量。
由上面两个式子可知，对于坐标系O-xyz中的点，两相机的图像坐标的对应转换矩阵为
Figure PCTCN2016111194-appb-000009
解线性方程组得到，O-xyz空间中点的三维坐标为：
Figure PCTCN2016111194-appb-000010
以单目相机构建双目立体视觉系统，两个相机之间具有同一个焦距f，根据SGBM立体匹配算法进行双目矫正求出，旋转矩阵约为单位矩阵。因此，在本文系统中两相机默认为平行关系，由此将上式变形为：
Figure PCTCN2016111194-appb-000011
根据机械结构定义系统的世界坐标系，本申请以水平旋转轴和竖直翻转轴的交点为原点，前后平移轴为z轴，视觉模块上下平移轴为y轴，左右平移轴为x轴，如图7中在工作台面1203中表示的系统世界坐标系所示。
此坐标系与相机坐标之间为绕x轴旋转90°因此根据旋转矩阵的构建，设世界坐标系某点为(xw,yw,zw)，则有:
Figure PCTCN2016111194-appb-000012
其中[Tx Ty Tz]T为世界坐标系和相机坐标系之间的平移向量。通过确 定相机初始位置求解该平移向量，并将相机初始位置作为系统唯一相机坐标系，即所有通过双目系统求出的坐标都先转化为初始位置相机坐标下的坐标后才能进行下一步计算。
得到系统下图像中某点的世界坐标为：
Figure PCTCN2016111194-appb-000013
根据一种可行实施方式，步骤S200包括如图8所示的下述子步骤：
S210、首先将输入的模型进行网格分割，然后将封闭网格进行简化降低模型的数据量，通过基于拉普拉斯网格紧缩的方法使模型收缩直到塌陷为骨架，其中基于拉普拉斯的网格收缩需要反复迭代的解拉普拉斯方程，直到网格模型收缩成为骨架，如下为隐式的拉普拉斯方程：
Figure PCTCN2016111194-appb-000014
WL表示对角收缩力矩阵，WH为对角吸引力矩阵，第i个元素为WL，i(WH，i)，采用下面公式所示的最小二乘法对上述公式进行求解：
Figure PCTCN2016111194-appb-000015
其中，如图9(a)所示为输入的三维模型原图，(b)为三维模型骨架图。
计算出曲面表面点到骨架的最近距离值，即形状直径度量值(Shape Diameter Metric)。
S220、将输入的三维模型表面进行分割，先将模型按形状直径度量值使用K-means聚类，即认为初始只有一类，若表面点之间形状直径度量值的差小于设定阈值m则聚为一类，否则将其作为新的聚类中心，最后得到{T1}，{T2}，…，{Tn}，n>0；然后对上述聚类做调整，得到模型表面分割边界。
S230、由模型表面分割的边界得到模型的分割平面，将输入的三维模型根据分割平面粗略划分成几个模块。
S240、手动选择第一个打印的模块，第一个模块的基平面应为水平 平面，根据模块之间的连接顺序确定其他模块的打印顺序，每一模块都可以在打印头和工作台面夹角不变的情况下无外界支撑的打印出来，这就要求每一模块的表面都是安全面。
其中满足下式的平面都是可以无外界支撑打印的安全面：
Figure PCTCN2016111194-appb-000016
Figure PCTCN2016111194-appb-000017
为模型表面切平面法向量，
Figure PCTCN2016111194-appb-000018
为打印头方向向量，amax为在模型可无外界支撑打印情况下打印头与模型表面切平面的最大夹角。
S250、最后根据“分割平面不可两两相交”和“完成分割后的所有模块基平面法向量方向(由先打印模块指向后打印模块)指向上方”这两个原则将分割不好的区域合并，再根据“打印头与模块表面切平面的夹角不能大于amax”进行精确划分，随后进行平面调整，将相邻模块之间的分割平面变为可打印的平面，分割结果如图9(c)所示。这里所说的法向量方向指向上方，是指法向量没有竖直向下的分量。
对不能满足这两个条件的模型(例如存在较大悬垂部分的模型)，其不可避免的需要加支撑进行打印。我们正在讨论的无支撑打印方法不考虑这种情况。根据一种可行实施方式，步骤S300包括如图10所示的下述子步骤：
S310、按照步骤S200得到各模块的打印顺序打印，将每一块看成可以在打印头和工作台面夹角不变的情况下无外界支撑打印的模块进行打印，因此每个模块的打印易于实现，关于不同模块之间打印衔接问题，本申请通过解析之前生成的分割模块及打印顺序，按顺序分别生成各模块的Gcode，载入模块的Gcode进行打印，每打印完成一个模块，程序跳出当前模块的Gcode。
S320、如图11中旋转轴角度图所示，其中β是法向量V绕Y轴旋转到平面YOZ上的角度。设法向量V＝(a,b,c)在平面XOZ上的投影是向量v＝(a,0,c)，则向量V绕Y轴旋转的角度实质为向量V与Y轴构成的平面S1与向YOZ平面所构成的夹角。又因为向量v是向量V在XOZ平面的投影，所以平面S1与平面YOZ的夹角就是向量v与Z轴的夹角β。V'是V旋转到YOZ平面的向量，α是向量V'绕X轴旋转，使得向量V与Y轴平行所旋转的角度。向量V'与Y轴同时在平面YOZ上，所以α就是向量V'与 Y轴的夹角，根据旋转向量夹角公式的变形，两个角度为：
Figure PCTCN2016111194-appb-000019
因此，一个向量可以由α和β两个角度表示，令α1、β1表示工作台面当前位置的法向量，α2、β2表示工作台面目标位置的法向量，则有如下公式：
Figure PCTCN2016111194-appb-000020
其中α3、β3可表示转动角度。
开始打印之前，在工作台面上贴三个不共线的标记点，用相机采图后，提取图像上的标记点，先对图像作彩色直方图均衡化，再对彩色直方图均衡化后的图像做二值化处理，以图像R通道数值大于B通道和G通道数值2倍作为约束条件，即
Figure PCTCN2016111194-appb-000021
根据图像连通域对二值化图像做轮廓提取，根据图中轮廓的位置求其与位置对应的角点作为标记点，如在上方的轮廓求轮廓最上端的角点，如在左下求左下方的角点，通过变换矩阵求出标记点在世界坐标系下的坐标。
根据图像上标记点的位置得到工作台面所在的平面及其法向量，根据空间中三个不共线点的平面方程，分别求出导板上三个点和模型上三个点所构成平面的法向量。假设模型上三个不共线点的坐标是(x1,y1,z1)，(x2,y2,z2)，(x3,y3,z3)，则根据平面方程点法式，设平面方程为：
A(x-x1)+B(y-y1)+C(z-z1)＝0
带入点坐标求解系数A，B，C为：
Figure PCTCN2016111194-appb-000022
若设其法向量为
Figure PCTCN2016111194-appb-000023
则有：
Figure PCTCN2016111194-appb-000024
如果法向量竖直向上，则开始打印，如果法向量不是竖直向上的，计算出工作台面所在的平面法向量记为α1、β1，竖直向上的向量计记为α2＝0、β2＝0，计算出旋转角度进行转动，直到工作台面转动到水平位置(法向量竖直向上)为止。
S330、打印完一个模块后控制工作台带动已打印好的模块一起旋转：打印完当前模块后，我们已知工作台当前位置及其法向量α1、β1；打印过程中，我们控制3D模型同步于打印进程变化，将3D模型转到目标位置(已打印模块上提供的待打印模块基平面法向量竖直向上)后，计算出此时工作台位置(即目标位置)的位置及其法向量α2、β2，计算出转动角度后进旋先转控制。
S340、旋转过程需要进行视觉监测，工业相机主要对打印平面进行视觉监控，因此我们程序只要在完成控制工作台旋转后，采集一张图片，通过分析这张图片得到已打印部分的俯视轮廓，得到该轮廓的最小外接矩形并计算出矩形长宽比；同时计算出同步于打印进程的3D模型俯视轮廓，得到其最小外接矩形并计算矩形长宽比。如果已打印部分的俯视轮廓的最小外接矩形长宽比与同步于打印进程的3D模型俯视轮廓最小外接矩形长宽比在误差允许的范围内大致相等，我们认为旋转到位，如果超出了误差允许范围，则重复上述步骤直至旋转到位。
机械旋转到位后读入下一个模块的Gcode进行打印，以此类推，直至所有的模块打印完。
本申请实施例的多轴机械系统与视觉监视相结合的多自由度3D打印方法与装置具有如下优点：
1)节约打印材料，节省人工去除支撑的时间；
2)可打印性，此多轴3D打印的方法，可以以最少的外界支撑打印出 任何复杂模型，适用性强。因此，本申请具有一定的应用价值和意义。
需要指出，前面描述的打印装置和方法仅仅是能够实现本申请的具体实施例。本领域技术人员在本申请的构思下，可以对这些实施例做出各种改造。例如，本申请的打印装置广义上可以包括一个由打印机构(包括但不限于FDM打印机构)和可转动工作台组成的至少五个自由度(三个移动自由度和两个转动自由度)的机械系统，其中可转动工作台具有相对于两个空间正交方向的转动自由度，而沿三个空间正交方向的移动自由度可以根据需要而在FDM打印机构和可转动工作台之间分配。
本申请的机械系统的至少五个自由度以下述方式分配，即打印机构仅具有移动自由度而不具有转动自由度，工作台具有转动自由度和可能有的移动自由度。这样，在打印时，打印头总是处在竖直向下的方位，容易确保打印头的定位精度。
此外，为实现机械系统的至少五个自由度，各式各样的结构可以采用，例如前面描述的电机、各种作动缸等等。
此外，在附图中所示的例子中，打印头为挤出式打印头。然而，本申请同样适用于其它形式的打印头。
因此，本申请的范围并不局限于前面所描述的细节。在不偏离本申请的基本原理的情况下，可针对这些细节做出各种修改。

Claims (16)

  1. 一种多自由度3D打印装置，包括打印机构、可转动工作台、视觉检测机构和控制装置；
    其中，所述打印机构包括打印头，所述可转动工作台包括工作台面，所述打印头适于在所述工作台面上进行打印，所述打印机构和可转动工作台组合起来具有至少三个在不同方向上的移动自由度，所述可转动工作台具有至少两个相对于不同方向的转动自由度；
    所述视觉检测机构包括相机，所述相机被安装成与所述打印头一体地移动；
    所述控制装置被设置成将待打印的三维模型分割为多个模块，并且在打印每个模块之前，通过所述相机监视所述可转动工作台上的已打印模块上提供的待打印模块基平面的方位，由此控制所述可转动工作台转动以使待打印模块基平面位于适合被所述打印头实施打印的方位，使得模块在打印过程中受到已打印模块的充分支撑。
  2. 如权利要求1所述的多自由度3D打印装置，其中，所述打印机构包括竖直移动电机组件和第一水平移动电机组件，所述竖直移动电机组件沿着竖直方向驱动所述打印头移动，所述第一水平移动电机组件沿着与竖直方向垂直的第一水平方向驱动所述打印头移动；
    所述可转动工作台包括第二水平移动电机组件、第一旋转电机组件和第二旋转电机组件，所述第二水平移动电机组件沿着与竖直方向和第一水平方向垂直的第二水平方向驱动所述工作台面移动，所述第一旋转电机组件驱动所述工作台面绕一条竖直旋转轴线旋转，所述第二旋转电机组件驱动所述工作台面绕一条水平旋转轴线转动。
  3. 如权利要求2所述的多自由度3D打印装置，其中，所述第一旋转电机组件、第二旋转电机组件和工作台面设置在所述第二水平移动电机组件的输出端并且由所述第二水平移动电机组件驱动；所述第二旋转电机组件和工作台面设置在所述第一旋转电机组件的输出端并且由所述第一旋转电机组件驱动；所述工作台面设置在所述第二旋转电机组件的输出端，并由所述第二旋转电机组件驱动。
  4. 如权利要求2或3所述的多自由度3D打印装置，其中，在所述 第一旋转电机组件未驱动第二旋转电机组件和工作台面旋转的状态下，所述水平旋转轴线沿所述第一水平方向延伸。
  5. 如权利要求1至4中任一项所述的多自由度3D打印装置，其中，所述控制装置将所述相机的监视图像与待打印模块基平面相比较而确定待打印模块基平面是否已到达适合被所述打印头实施打印的方位。
  6. 如权利要求1至5中任一项所述的多自由度3D打印装置，其中，所述适合被所述打印头实施打印的方位满足下述条件：待打印模块的基平面处于水平，并且所述基平面的法向量竖直向上。
  7. 如权利要求6所述的多自由度3D打印装置，其中，所述适合被所述打印头实施打印的方位还满足下述条件：在每个模块的打印过程中，打印头与该模块的基平面之间的夹角与直角之间的差值不大于设定的极限值。
  8. 如权利要求6或7所述的多自由度3D打印装置，其中，所述适合被所述打印头实施打印的方位还满足下述条件：待打印模块的重心在所述基平面中的竖直方向垂足落在所述基平面的外轮廓线内，优选位于所述基平面的几何中心处或附近。
  9. 如权利要求1至8中任一项所述的多自由度3D打印装置，其中，所述控制装置被设置成使每个分割出的模块在所述打印头和所述工作台面之间夹角不变的情况下仅由已打印模块支撑着打印，同时确定每一模块打印的顺序。
  10. 如权利要求1至9中任一项所述的多自由度3D打印装置，其中，所述相机包括单一的相机，所述控制装置通过以单目相机构建伪双目立体视觉系统进行双目测量方式确定待打印模块基平面的角度变化；或者
    所述相机包括一对相机，布置在所述打印头的两侧，所述控制装置基于所述一对相机的视差通过双目立体视觉测量方式确定待打印模块基平面的角度变化。
  11. 如权利要求1至10中任一项所述的多自由度3D打印装置，其中，所述控制装置被设置成以如下方式分割待打印的三维模型：
    得到三维模型的骨架，计算出骨架点对应曲面点集的形状直径度量值；
    将输入的三维模型进行模型表面分割，其中所述形状直径度量值被 用作分割时的调整因素；
    基于模型表面分割的边界将输入的三维模型初步划分成多个模块；
    选择第一个打印的模块，根据模块之间的连接顺序确定其他模块的打印顺序；
    对初步划分的多个模块进行精确划分，使相邻模块之间的分割平面变为可打印的平面。
  12. 如权利要求11所述的多自由度3D打印装置，其中，所述控制装置被设置成对基于模型表面分割的边界划分出的多个模块进行调整，对不满足下述条件的模块进行合并：
    模块间的分割平面不可两两相交、并且完成分割后的所有模块基平面法向量方向指向上方。
  13. 如权利要求11或12所述的多自由度3D打印装置，其中，所述控制装置被设置成对相邻模块之间的分割平面进行调整，使得打印时打印头与待打印模块表面的切平面之间的夹角不大于设定的极限值。
  14. 一种多自由度3D打印方法，包括下述步骤：
    输入待打印的三维模型；
    将待打印的三维模型分割为多个模块；
    对于每个模块，使工作台面位于适合被打印头实施打印的方位，以使得模块在打印过程中受到与其交界的已打印模块的充分支撑；
    利用打印头在所述工作台面上顺序打印出各模块。
  15. 如权利要求14所述的多自由度3D打印方法，其中，利用权利要求1至13中任一项所述的多自由度3D打印装置实施打印。
  16. 如权利要求14所述的多自由度3D打印方法，其中，包含权利要求1至13中任一项所述的多自由度3D打印装置中的相关特征。
PCT/CN2016/111194 2016-12-21 2016-12-21 多轴机械系统与视觉监视相结合的3d打印方法与装置 WO2018112770A1 (zh)

Priority Applications (3)

Application Number Priority Date Filing Date Title
CN201680074907.XA CN109414881A (zh) 2016-12-21 2016-12-21 多轴机械系统与视觉监视相结合的3d打印方法与装置
PCT/CN2016/111194 WO2018112770A1 (zh) 2016-12-21 2016-12-21 多轴机械系统与视觉监视相结合的3d打印方法与装置
US16/446,314 US11225018B2 (en) 2016-12-21 2019-06-19 3D printing method and device with multi-axis mechanical system and visual surveillance

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2016/111194 WO2018112770A1 (zh) 2016-12-21 2016-12-21 多轴机械系统与视觉监视相结合的3d打印方法与装置

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US16/446,314 Continuation US11225018B2 (en) 2016-12-21 2019-06-19 3D printing method and device with multi-axis mechanical system and visual surveillance

Publications (1)

Publication Number Publication Date
WO2018112770A1 true WO2018112770A1 (zh) 2018-06-28

Family

ID=62624042

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2016/111194 WO2018112770A1 (zh) 2016-12-21 2016-12-21 多轴机械系统与视觉监视相结合的3d打印方法与装置

Country Status (3)

Country Link
US (1) US11225018B2 (zh)
CN (1) CN109414881A (zh)
WO (1) WO2018112770A1 (zh)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109501241A (zh) * 2018-11-05 2019-03-22 北京工业大学 立体视觉监视的高强度多方向fdm 3d打印方法
CN110136205A (zh) * 2019-04-12 2019-08-16 广州极飞科技有限公司 多目相机的视差校准方法、装置及系统
CN110394422A (zh) * 2019-08-20 2019-11-01 西安空天能源动力智能制造研究院有限公司 一种砂型打印过程在线监控装置及方法
CN112123761A (zh) * 2020-09-26 2020-12-25 共享智能铸造产业创新中心有限公司 打印测试纸自动识别机构及3d打印机
US11225018B2 (en) 2016-12-21 2022-01-18 Beijing University Of Technology 3D printing method and device with multi-axis mechanical system and visual surveillance
CN114147239A (zh) * 2021-12-07 2022-03-08 浙江机电职业技术学院 一种slm成型过程参数监测系统
CN114734448A (zh) * 2022-05-11 2022-07-12 上海交通大学 一种用于船舶理料装备的板材零件抓取方法及装置

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11565468B1 (en) * 2017-12-07 2023-01-31 Redwire Space, Inc. System and method for hybrid additive and subtractive manufacturing with dimensional verification
CN108973124B (zh) * 2018-10-12 2024-03-08 吉林大学 一种三角洲式五自由度3d打印机
CN113119458B (zh) * 2019-12-31 2022-08-09 上海联泰科技股份有限公司 3d打印设备的标定系统、方法及3d打印设备
CN112659544B (zh) * 2020-12-02 2022-06-07 西安交通大学 五轴3d打印机的薄壁管状模型切片方法、系统及打印方法
CN112884847B (zh) * 2021-03-02 2022-08-09 济南大学 一种双相机标定方法及系统
CN113276422B (zh) * 2021-04-30 2022-07-01 上海工程技术大学 一种fdm打印喷头受力监控方法、存储介质及相关装置
US20220371284A1 (en) * 2021-05-07 2022-11-24 New York University Display guided high-accuracy robotic navigation and motion control system and methods
US11642854B2 (en) * 2021-06-10 2023-05-09 Arris Composites Inc. Additive manufacturing path generation
CN116141674B (zh) * 2022-12-12 2024-04-12 合肥工业大学 一种基于视觉测距的3d打印机基板自动调平装置及方法
CN116160685B (zh) * 2023-03-27 2024-09-03 北京祥晨伟业科技发展有限公司 一种3d打印方法、系统、终端及存储介质

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104859147A (zh) * 2015-04-24 2015-08-26 常州大学 一种基于并联机构的四自由度3d打印设备
CN105818373A (zh) * 2015-01-17 2016-08-03 王奉瑾 一种3d打印薄壳体的方法
CN106163771A (zh) * 2013-11-13 2016-11-23 Abb技术有限公司 用于机器人3d打印的方法及系统
CN106217874A (zh) * 2016-07-29 2016-12-14 攸潇潇 一种四轴三维打印机

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9421716B2 (en) * 2012-08-08 2016-08-23 Makerbot Industries, Llc Photo booth for three-dimensional images
US9815268B2 (en) * 2013-03-22 2017-11-14 Markforged, Inc. Multiaxis fiber reinforcement for 3D printing
WO2014205642A1 (en) * 2013-06-25 2014-12-31 Thomson Licensing Method and apparatus for consistent segmentation of 3d models
CN114734628A (zh) * 2014-06-23 2022-07-12 卡本有限公司 由具有多重硬化机制的材料制备三维物体的方法
WO2017106965A1 (en) * 2015-12-21 2017-06-29 Ord Solutions Inc. Method and apparatus for large format three-dimensional printing
WO2018112770A1 (zh) 2016-12-21 2018-06-28 北京工业大学 多轴机械系统与视觉监视相结合的3d打印方法与装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106163771A (zh) * 2013-11-13 2016-11-23 Abb技术有限公司 用于机器人3d打印的方法及系统
CN105818373A (zh) * 2015-01-17 2016-08-03 王奉瑾 一种3d打印薄壳体的方法
CN104859147A (zh) * 2015-04-24 2015-08-26 常州大学 一种基于并联机构的四自由度3d打印设备
CN106217874A (zh) * 2016-07-29 2016-12-14 攸潇潇 一种四轴三维打印机

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11225018B2 (en) 2016-12-21 2022-01-18 Beijing University Of Technology 3D printing method and device with multi-axis mechanical system and visual surveillance
CN109501241A (zh) * 2018-11-05 2019-03-22 北京工业大学 立体视觉监视的高强度多方向fdm 3d打印方法
CN109501241B (zh) * 2018-11-05 2020-12-04 北京工业大学 立体视觉监视的高强度多方向fdm 3d打印方法
US11360464B2 (en) 2018-11-05 2022-06-14 Beijing University Of Technology High intensity multi direction FDM 3D printing method for stereo vision monitoring
CN110136205A (zh) * 2019-04-12 2019-08-16 广州极飞科技有限公司 多目相机的视差校准方法、装置及系统
CN110394422A (zh) * 2019-08-20 2019-11-01 西安空天能源动力智能制造研究院有限公司 一种砂型打印过程在线监控装置及方法
CN112123761A (zh) * 2020-09-26 2020-12-25 共享智能铸造产业创新中心有限公司 打印测试纸自动识别机构及3d打印机
CN114147239A (zh) * 2021-12-07 2022-03-08 浙江机电职业技术学院 一种slm成型过程参数监测系统
CN114734448A (zh) * 2022-05-11 2022-07-12 上海交通大学 一种用于船舶理料装备的板材零件抓取方法及装置
CN114734448B (zh) * 2022-05-11 2023-11-07 上海交通大学 一种用于船舶理料装备的板材零件抓取方法及装置

Also Published As

Publication number Publication date
CN109414881A (zh) 2019-03-01
US20190299523A1 (en) 2019-10-03
US11225018B2 (en) 2022-01-18

Similar Documents

Publication Publication Date Title
WO2018112770A1 (zh) 多轴机械系统与视觉监视相结合的3d打印方法与装置
US11768481B2 (en) System and workstation for the design, fabrication and assembly of bio-material constructs
US9878495B2 (en) Three-dimensional printing of large objects
US11207852B2 (en) Three dimensional printing on three dimensional objects
EP3863791B1 (en) System and method for weld path generation
US20140039663A1 (en) Augmented three-dimensional printing
CN105666877A (zh) 具有三维图形反馈系统的3d打印机及其打印方法
TWI571380B (zh) 一種三維物件列印方法及其系統
KR101539357B1 (ko) 3차원 형상을 가지는 면을 따라 적층하는 3차원 성형 장치 및 성형 방법
US20150251358A1 (en) Three dimensional printing apparatus and method for controlling printing head thereof
JP6763993B2 (ja) ３ｄプリンタのオブジェクト境界を検出する方法
US20150057780A1 (en) Three-dimensional printing apparatus
Bausch et al. 3D printing onto unknown uneven surfaces
JP2016097657A (ja) 画像情報処理装置、画像情報処理方法およびプログラム、並びに撮像装置
Gibson et al. Software issues for additive manufacturing
CN106584840A (zh) 一种单向大尺寸制件的3d打印方法及其打印装置
JP2017056574A (ja) 立体造形装置、立体造形方法及び立体造形装置の制御プログラム
Preissler et al. Approach for process control in additive manufacturing through layer-wise analysis with 3-dimensional pointcloud information
Hattab et al. Interactive fabrication of csg models with assisted carving
Inzerillo et al. From SFM to 3D PRINT: Automated workflow addressed to practitioner aimed at the conservation and restauration
EP3616885A1 (en) Three-dimensional printing method and three-dimensional printing device
CN115891174A (zh) 三维可视化温控3d打印方法及3d打印机
JP6868180B2 (ja) 造形装置、造形物受注管理制御装置、造形物受注管理制御プログラム
JP6840944B2 (ja) ３次元データ生成装置、造形装置、造形物の製造方法及びプログラム
Minhat et al. Advanced manufacturing of an aircraft component (fish-head): A technology review on the fabrication

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 16924708

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC

122 Ep: pct application non-entry in european phase

Ref document number: 16924708

Country of ref document: EP

Kind code of ref document: A1