CN114952127B - Calibration model and method for 3D vision camera and mechanical arm for welding - Google Patents

Abstract

The invention relates to a vision guide technology, in particular to a calibration model and a calibration method for a 3D vision and mechanical arm for welding, which comprises a calibration structure, a locking mechanism and a model body; the calibration structure is movably arranged above the rotary table along the radial direction of the rotary table, and the rotary table is coaxially and rotatably matched with the model platform; after the model installation part and the manifold are pre-installed, the position of the calibration structure can be finely adjusted, the central spine calibration part in the calibration structure is ensured to be positioned on the axis of the welding gun barrel, the welding gun barrel on the mechanical arm and the 3D camera are positioned in the same coordinate system, and the guide error of the 3D camera is reduced. In the calibration method, the method of installing the calibration model, setting the origin, setting the track route and importing data is adopted to enable the presented three-dimensional track to be closer to the preset welding path, so that the error is reduced; the calculation amount of the point position is smaller, the calculation load of a host is reduced, and meanwhile the presentation rate of the path can be improved.

Description

Calibration model and method for 3D vision camera and mechanical arm for welding

Technical Field

The invention relates to a visual guidance technology, in particular to a calibration model and a calibration method for a 3D visual camera and a mechanical arm for welding.

Background

When the 3D vision guides the mechanical arm to move to execute welding work, the coordinates of the 3D vision camera and the actual coordinates of the mechanical arm need to be calibrated to ensure that the two are in the same coordinate system; the coordinates of the 3D vision camera are overlapped with the coordinate height of the mechanical arm; the mechanical arm motion may be directed by a 3D visual camera.

The guiding means commonly used at present comprise relative value guiding and absolute value guiding; in industrial production, especially in the visual guidance welding technology, absolute value guidance is mostly adopted; the principle of absolute value guidance is that the coordinates of the coordinate mechanical arms of the 3D vision camera are overlapped and unified to form a common coordinate system; and capturing the space point position coordinates of the image by using a visual system of the 3D visual camera, thereby calibrating the space coordinates of the mechanical arm.

Although the application of the absolute value guiding technology is very wide, for example, the chinese patent proposes a calibration model and a calibration method for a laser 3D vision camera and a six-axis manipulator (application number 202010590634.2); the patent proposes that the existing absolute value guiding technology is very good in compatibility with an operation method of a mechanical arm, and can be directly modified in an image if the actual project requirement needs to be modified, so that secondary calibration is not needed. There are still some drawbacks; including that the whole calibration frame must be made very complicated and costly in order to achieve ultra-high precision calibration.

To this end, the patent provides a calibration model for a laser 3D vision camera and a six-axis robot. The calibration model is in a circular block shape and comprises a central part, a middle part and an outer edge part, wherein the central part is provided with a circular boss, a dot of the circular boss is provided with a first groove, and the first groove is provided with a spine structure capable of being mounted and dismounted; the middle part is provided with a second annular groove at the periphery of the circular boss; the outer edge part is provided with cut edges at two sides of the circular block of the calibration module, so that the absolute value guide calibration of the laser 3D vision camera and the six-axis manipulator is realized, and the calibration model is simple in structure; as long as the condition that the 3D vision camera can scan the position of the flange plate is met, the calibration model can be used for carrying out ultrahigh-precision calibration actions of the 3D vision camera and the six-axis manipulator.

Although the calibration model provided in the patent can play a calibration role, the coordinate of the calibration model needs to be adjusted to coincide with the coordinate of the mechanical arm when the calibration model is used, and the calibration model and a common calibration model have a problem which is difficult to overcome; namely, the calibration model is installed and positioned once, and has no adjusting function, so that the coordinate of the calibration model is required to be ensured to be completely consistent with the coordinate of the mechanical arm before installation, and after the calibration model is firmly installed, if the calibration model is found to have deviation with the coordinate of the mechanical arm, the calibration model needs to be detached and debugged again, which is very inconvenient.

Disclosure of Invention

The invention aims to provide a calibration model and a calibration method for a 3D vision camera and a mechanical arm for welding, so as to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

a calibration model for a welded 3D vision camera and a mechanical arm comprises a calibration structure, a locking mechanism and a model body formed by a model mounting part and a model platform;

the calibration structure is movably arranged above the rotary table along the radial direction of the rotary table, and the rotary table is coaxially and rotatably matched with the model platform; a supporting plate is fixedly arranged in the center of the top of the rotating table, the supporting plate is along the diameter direction of the rotating table, and the calibration structure is movably arranged on the supporting plate;

the axial direction of the model mounting part and the manifold on the welding gun tube forms an X direction; the axial direction of the model platform forms a Y direction; a Z direction is formed in a direction vertical to the X direction and the Y direction;

the locking mechanism is used for restricting the freedom degree of the manifold and the model mounting part in the X direction, the freedom degree of the rotating platform in the Y direction and the freedom degree of the calibration structure on the supporting plate.

Calibration model of 3D vision camera and robotic arm for welding as described above: the calibration structure comprises a disc-shaped block body, an outer edge shielding bulge and a central spine calibration part; the outer edge shielding bulge is arranged at the edge of the disc-shaped block body, and the central spine calibration part is arranged at the center of the outer edge shielding bulge;

the model mounting part is fixed with a manifold on the welding gun tube, and the manifold on the welding gun tube is vertically fixed with the welding gun tube; the model installation part is used for fixedly installing the model platform on a welding gun tube of the mechanical arm in a coaxial mode.

Calibration model of 3D vision camera and robotic arm for welding as described above: a first containing cavity is formed in the model body, a second containing cavity is formed in the center of the bottom of the rotating table, the first containing cavity and the second containing cavity are coaxially arranged, and the top of the first containing cavity is communicated with the bottom of the second containing cavity;

the locking mechanism comprises a step external member which is rotatably arranged between the first containing cavity and the second containing cavity, and the upper part and the lower part of the step external member are respectively provided with a second cylindrical counter bore and a first cylindrical counter bore;

the first cylindrical counter bore is internally threaded with a first locking piece, the upper part of the first locking piece is cylindrical, and the lower part of the first locking piece is square; the bottom in first appearance chamber has been seted up the intercommunication the inside lockhole that just is square No. one of model installation department, the inner wall threaded connection of retaining member upper portion outer wall and cylindricality counter bore No. one, the lower part of retaining member and lockhole slip grafting No. one.

Calibration model of 3D vision camera and robotic arm for welding as described above: a third locking part is further arranged in the first accommodating cavity, and an inner wall of the third locking part is provided with an inner thread matched with the outer thread of the outer wall of the upper part of the step suite;

no. three the outer fringe department of retaining member is provided with the bead, is provided with the guide slot on the inner wall in first appearance chamber, the guide slot with the gomphosis that slides of bead, just No. three the last reason of retaining member is provided with first fixed knot and constructs.

Calibration model of 3D vision camera and robotic arm for welding as described above: the first fixing structure comprises an elastic sheet fixed on the upper edge of the third locking piece, a first positioning piece fixed on the elastic sheet and a supporting piece fixed on the upper edge of the third locking piece;

a supporting hole in sliding fit with the supporting piece is formed in the first positioning piece.

Calibration model of 3D vision camera and robotic arm for welding as described above: a second locking piece is arranged in the second cylindrical counter bore, the lower part of the second locking piece is cylindrical, and the upper part of the second locking piece is square; the top of the second accommodating cavity is provided with a second locking hole, the outer wall of the lower part of the second locking part is in threaded connection with the inner wall of the second cylindrical counter bore, and the upper part of the second locking part is in sliding insertion connection with the second locking hole;

no. two lockholes run through revolving stage and layer board, the upper portion of No. two retaining members is provided with second fixed knot and constructs.

Calibration model of 3D vision camera and robotic arm for welding as described above: a sliding cavity is formed in the upper part of the second locking part, the second fixing structure comprises a second positioning part in sliding fit with the sliding cavity, and a pressure spring is arranged in the sliding cavity;

an opening is formed in the upper portion of the sliding cavity, the opening is smaller than the cross-sectional size of the sliding cavity, a sliding block is integrally arranged on the lower portion of the second positioning piece, the sliding block is in sliding fit with the inner wall of the sliding cavity, and the upper portion of the second positioning piece penetrates through the opening and extends out of the sliding cavity;

one end of the pressure spring is attached to the bottom of the sliding cavity, and the other end of the pressure spring is attached to the bottom surface of the sliding block.

Calibration model of 3D vision camera and robotic arm for welding as described above: the lower parts of two sides of the disc-shaped block body are respectively provided with a clamping pin, two sides of the supporting plate are provided with a clamping groove along the length direction of the supporting plate, and the disc-shaped block body is movably arranged on the supporting plate through the sliding clamping of the clamping pins and the clamping grooves.

Calibration model of 3D vision camera and robotic arm for welding as described above: a first bevel gear is fixed on the outer wall of the lower part of the ladder suite, the first bevel gear is meshed with a second bevel gear, a penetrating shaft is rotatably arranged on the model platform, one end of the penetrating shaft extends into the first cavity, and the other end of the penetrating shaft extends out of the model platform;

the second bevel gear is fixed at one end of the penetrating shaft extending into the first cavity, and a knob is fixed at the other end of the penetrating shaft.

A method for calibrating a 3D visual camera and a mechanical arm by using the calibration model comprises the following steps:

firstly, calibrating the installation of a model, and sleeving a model installation part on a model body with a coaxial gap of a manifold on a welding gun tube; rotating the rotating table to enable the supporting plate to rotate around the Y direction to be parallel to the X direction; adjusting the calibration structure to move along the radial direction of the supporting plate on the rotating table, so that the calibration structure and the welding gun barrel are located at the same position in the X direction; the rotation freedom degree of the manifold and the model installation part in the X direction, the movement freedom degree of the manifold and the model installation part in the X direction, the rotation freedom degree of the rotating platform in the Y direction and the movement freedom degree of the calibration structure on the supporting plate are restrained by using the locking mechanism; the 3D vision camera can identify a central spine calibration part calibrated to the center of the calibration structure, and a welding gun tube on the mechanical arm and the 3D vision camera are ensured to be positioned under the same coordinate system;

setting an origin, capturing a central spine calibration part in the calibration structure through a 3D visual camera, acquiring coordinate data of the central spine calibration part in a coordinate system of the 3D visual camera, and initializing the acquired coordinate data to set the coordinate data as the origin of (0,0,0);

setting a track route, and selecting a plurality of continuous discrete typical point positions on a preset welding path, wherein the discrete typical point positions are matched with the characteristics of the preset welding path; counting coordinate data of the discrete typical point positions in a coordinate system of the 3D vision camera to form a data chain; sequentially inputting the formed data chain into a database according to the continuous point location distribution trend;

and step four, data import, namely importing coordinate point data in the database into a 3D vision camera imaging system, generating a continuous three-dimensional track route in the imaging system according to the imported coordinate point data, and checking whether the presented three-dimensional track is consistent with a preset welding path.

Compared with the prior art, the invention has the beneficial effects that: in the invention, the model mounting part and the manifold are pre-mounted in a clearance fit manner, so that the mounting convenience is greatly improved. In addition, in the invention, the supporting plate is rotated to be parallel to the X direction around the Y direction by rotating the rotating table, and the position of the calibration structure can be adjusted in the X direction by adjusting the calibration structure to move along the radial direction of the supporting plate on the rotating table, so that the calibration structure and the welding gun barrel are positioned at the same position in the X direction; therefore, even if the welding gun barrel and the model platform are dislocated in the X direction in the pre-installation process, the calibration structure can move on the supporting plate, and the position difference between the calibration structure and the welding gun barrel in the X direction is eliminated;

by the locking mechanism, after the model mounting part and the manifold are pre-mounted, the calibration structure can be kept coaxial with the welding gun barrel, and the complicated debugging and mounting process is simplified; the model body and the manifold are fixed, the rotating table and the model body can be fixed, and the calibration structure and the supporting plate are fixed, so that the calibration model is fixed with the manifold; after the calibration model is pre-installed, the calibration structure is kept coaxial with the welding gun barrel in a fine adjustment mode, and all parts are fixed by means of the locking mechanism, so that the complicated debugging and installing processes are simplified.

In conclusion, after the model mounting part and the manifold are pre-mounted, the position of the calibration structure can be finely adjusted, the central spine calibration part in the calibration structure is ensured to be positioned on the axis of the welding gun barrel, the welding gun barrel on the mechanical arm and the 3D vision camera are positioned in the same coordinate system, and the guide error of the 3D vision camera is reduced.

Drawings

Fig. 1 is a schematic structural diagram of a calibration model of a 3D vision camera and a robot arm for welding.

Fig. 2 is a half sectional plan view of a 3D vision camera for welding and a calibration model a-a of a robot arm.

Fig. 3 is an enlarged view of a portion a in fig. 2.

Fig. 4 is a plan view of fig. 2, partially broken away.

Fig. 5 is a schematic view showing the structure of the disk-shaped block after being separated from the turntable and the pallet.

Fig. 6 is a schematic structural view of the calibration model after the disk-shaped block is separated from the rotating table and the pallet.

Fig. 7 is an enlarged view of fig. 6 at B.

Fig. 8 is a schematic view of the first fixing structure, the third locking member and the rib.

Fig. 9 is a half sectional view of the locking mechanism of fig. 2.

Fig. 10 is a plan view of fig. 9 disassembled.

FIG. 11 is a three-dimensional perspective view of a 3D vision camera and calibration model of a robotic arm for welding, half cut along a-a.

Fig. 12 is an enlarged view at C in fig. 11.

Fig. 13 is a schematic structural view of the model body removed from fig. 11.

In the figure: 1. a model platform; 2. a model mounting section; 3. a disk-shaped block body; 4. the outer edge shields the bulge; 5. a central spine marking part; 6. a support plate; 7. a rotating table; 8. a first cavity; 9. a second cavity; 10. a ladder kit; 11. a first locking member; 12. a first lock hole; 13. a second locking member; 14. a third locking piece; 15. a convex edge; 16. a guide groove; 17. an elastic sheet; 18. a first positioning piece; 19. a support member; 20. a second positioning element; 21. a pressure spring; 22. clamping a pin; 23. a card slot; 24. a first bevel gear; 25. a second bevel gear; 26. penetrating a shaft; 27. a knob.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

Referring to fig. 1 to 13, as an embodiment of the present invention, the calibration model of the 3D vision camera and the mechanical arm for welding includes an integrally formed model platform 1 and a model mounting part 2; the model mounting part 2 and the model platform 1 form a model body; the model mounting part 2 is used for coaxially and fixedly mounting the model platform 1 on a welding gun tube of the mechanical arm;

the manifold on the welding gun tube is fixed to the model mounting part 2, and the manifold on the welding gun tube is vertically fixed to the welding gun tube, and the axis of the model platform 1 is vertical to the axis of the model mounting part 2, so that the welding gun tube and the model platform 1 are coaxial through the connection of the model mounting part 2 and the manifold.

The calibration model is characterized in that a disc-shaped block body 3 is arranged in the center above the model platform 1, a circle of outer edge shielding protrusion 4 is arranged on the edge of the disc-shaped block body 3, a central spine calibration part 5 is arranged at the circle center of the outer edge shielding protrusion 4, the disc-shaped block body 3, the outer edge shielding protrusion 4 and the central spine calibration part 5 jointly form a calibration structure, and the function of the calibration structure is the same as that of the prior art, particularly the calibration model which is used for a laser 3D vision camera and a six-axis manipulator and is applied to the application number 202010590634.2 and is used in the calibration model and the calibration method.

Through installing the soldered connection department at the arm with demarcating the structure, make the identifiable centre spine demarcation portion 5 of demarcating in the structure of demarcating of 3D vision camera to guarantee that arm and 3D vision camera are in under the same coordinate system, so that guide the arm action through 3D vision camera, carry out the welding.

The calibration structure is movably arranged above the rotating platform 7 along the radial direction of the rotating platform 7, and the rotating platform 7 is coaxially and rotatably matched with the model platform 1;

specifically, a supporting plate 6 is fixedly arranged at the center of the top of the rotating platform 7, the supporting plate 6 moves along the diameter direction of the rotating platform 7, and the calibration structure is movably arranged on the supporting plate 6.

Because the model body is coaxially installed at the manifold on the welding gun barrel through the model installation part 2, in the actual installation process, in order to install conveniently, the inner diameter of the model installation part 2 is generally larger than the outer wall of the manifold, so that the pre-installation of the model installation part 2 and the manifold is realized in a clearance fit mode.

Just because the model mounting part 2 and the manifold are in clearance fit relation when pre-mounted, the two are easy to loosen in the axial direction; the axial direction of the model mounting part 2 and the manifold on the welding gun tube is X direction; the axial direction of the model platform 1 is the Y direction; meanwhile, the direction perpendicular to the X direction and the Y direction is the Z direction; the looseness of the mold mounting part 2 and the manifold in the X direction causes the mold platform 1 and the welding gun tube to move in the X direction, resulting in misalignment.

In the existing calibration model, if the coordinate of the calibration model is overlapped with the coordinate height of the mechanical arm, the calibration model and the mechanical arm are coaxial in height; therefore, when the calibration model is installed, the requirement on the installation accuracy is high, and generally, the installation accuracy can be improved by installing the calibration model in an interference fit mode, but the installation convenience is also reduced.

In the invention, the model mounting part 2 is pre-mounted in clearance fit with the manifold, so that the mounting convenience is greatly improved. In addition, in the invention, the supporting plate 6 is rotated to be parallel to the X direction around the Y direction by rotating the rotating table 7, and the position of the calibration structure can be adjusted in the X direction by adjusting the calibration structure to move along the radial direction of the supporting plate 6 on the rotating table 7, so that the calibration structure and the welding gun barrel are positioned at the same position in the X direction; therefore, even if the welding gun barrel and the model platform 1 are dislocated in the X direction in the pre-installation process, the calibration structure can move on the supporting plate 6, and the position difference of the calibration structure and the welding gun barrel in the X direction is eliminated.

The inside of model body has set up locking mechanical system, locking mechanical system is used for retraining manifold and the ascending rotational degree of freedom of model installation department 2 in X, the ascending degree of freedom of movement of manifold and model installation department 2 in X, the rotational degree of freedom of revolving stage 7 in Y to and the degree of freedom of movement of calibration structure on layer board 6.

The manifold and the model mounting part 2 are in clearance fit, so that the manifold and the model mounting part can rotate relatively and can also slide relatively along the X direction; meanwhile, the rotary table 7 is in rotating fit with the model platform 1, so that the rotary table 7 and the model platform 1 can rotate relatively; in addition, the calibration structure is movably arranged on the supporting plate 6, so that the calibration structure can move in the X direction;

by the locking mechanism, after the model mounting part 2 and the manifold are pre-mounted, the model body and the manifold can be fixed, meanwhile, the rotating platform 7 and the model body can be fixed, and the calibration structure and the supporting plate 6 are fixed, so that the calibration model is fixed with the manifold; after the calibration model is pre-installed, the calibration structure is kept coaxial with the welding gun barrel in a fine adjustment mode, and all parts are fixed by means of the locking mechanism, so that the complex debugging and installing process is simplified.

It should be noted that, in the pre-installation process, the model installation part 2 and the manifold are in clearance fit, so that when the two are loosened in the axial direction, an included angle and a non-coaxial angle are also generated between the axis of the model installation part 2 and the axis of the manifold; this angle exists in the plane formed by the X direction and the Z direction, and in order to eliminate the angle, the rotating table 7 is arranged in a rotating fit relationship with the model platform 1, so that the calibration structure can rotate around the Y direction on the plane formed by the X direction and the Z direction, and the angle is eliminated.

As a further scheme of the invention, a first cavity 8 is arranged in the model body, a second cavity 9 is arranged in the center of the bottom of the rotary table 7, the first cavity 8 and the second cavity 9 are coaxially arranged, and the top of the first cavity 8 is communicated with the bottom of the second cavity 9;

the locking mechanism comprises a step external member 10 which is rotatably arranged between a first containing cavity 8 and a second containing cavity 9, and the upper part and the lower part of the step external member 10 are respectively provided with a second cylindrical counter bore and a first cylindrical counter bore;

a first locking piece 11 is connected with the first cylindrical counter bore in a threaded manner, the upper part of the first locking piece 11 is cylindrical, and the lower part of the first locking piece 11 is square; the intercommunication has been seted up to the bottom in first appearance chamber 8 the inside lockhole 12 that just is square No. 2 of model installation departments, the inner wall threaded connection of retaining member 11 upper portion outer wall and a cylindricality counter bore, the lower part of retaining member 11 and lockhole 12 slip grafting.

When the ladder suite 10 is rotated, the internal threads on the inner wall of the first cylindrical counter bore act on the external threads on the outer wall of the upper part of the first locking piece 11; the lower part of the first locking piece 11 is inserted into the first locking hole 12, so that the first locking piece 11 does not rotate along with the step kit 10; finally, under the action of the internal thread on the inner wall of the first cylindrical counter bore and the external thread on the outer wall of the upper part of the first locking piece 11, the lower part of the first locking piece 11 is driven to move towards the model mounting part 2, so that the lower part of the first locking piece 11 penetrates through the first locking hole 12 and is abutted against the outer wall of the manifold; the freedom of rotation of the manifold and the mold mounting portion 2 in the X direction and the freedom of movement of the manifold and the mold mounting portion 2 in the X direction are restricted.

Note that the first locking member 11 moves in the Y direction toward the model mounting portion 2, so that when the lower portion of the first locking member 11 is fitted to the inner wall of the model mounting portion 2 and fixed to the manifold, the manifold and the model mounting portion 2 are completely restrained in the Y direction, and therefore, when an included angle is formed between the mounting portion 2 and the axis of the manifold, the included angle exists in a plane formed by the X direction and the Z direction.

As a further scheme of the invention, a third locking member 14 is further arranged in the first accommodating cavity 8, and an inner wall of the third locking member 14 is provided with an inner thread matched with an outer thread on the outer wall of the upper part of the step kit 10;

no. three retaining member 14's outer fringe department is provided with bead 15, is provided with guide slot 16 on the inner wall in first appearance chamber 8, guide slot 16 with bead 15 slip gomphosis, just No. three retaining member 14's last reason is provided with first fixed knot and constructs.

When rotating ladder external member 10 and driving the lower part of retaining member 11 and moving towards model installation department 2, drive first fixed knot through No. three retaining members 14 and move up to it is fixed with revolving stage 7 with the help of the bottom surface of first fixed knot structure conflict revolving stage 7, makes revolving stage 7 lose relative model platform 1 pivoted ability.

Make No. three retaining member 14 can not rotate relative to the model body through the cooperation of bead 15 and guide slot 16, consequently, when rotating ladder external member 10, the external screw thread through ladder external member 10 upper portion outer wall acts on the internal thread on No. three retaining member 14 inner walls for No. three retaining member 14 upwards moves about, and drives first fixed knot and follows the activity of upwards, fixes revolving stage 7.

As a still further aspect of the present invention, the first fixing structure includes an elastic piece 17 fixed to an upper edge of the third locking member 14, a first positioning member 18 fixed to the elastic piece 17, and a supporting member 19 fixed to an upper edge of the third locking member 14;

the first positioning element 18 is provided with a supporting hole in sliding fit with the supporting element 19.

When the third locking member 14 moves upwards, the first positioning member 18 is driven to ascend through the elastic sheet 17, and the third locking member 14 continues to move upwards after the top of the first positioning member 18 ascends to abut against the bottom surface of the rotating platform 7; since the top of the first positioning member 18 already abuts against the bottom surface of the rotating table 7, when the third locking member 14 continues to move upward, the lower portion of the first positioning member 18 presses the elastic piece 17, so that the elastic piece 17 is elastically deformed; the elastic sheet 17 is elastically deformed to increase the contact force between the top of the first positioning member 18 and the bottom surface of the rotating platform 7, so as to increase the friction force between the top of the first positioning member 18 and the bottom surface of the rotating platform 7, thereby fixing the rotating platform 7.

The supporting holes and the supporting pieces 19 are provided to improve the stability of the first positioning member 18 and prevent the first positioning member 18 from falling down.

As a further scheme of the invention, a second locking member 13 is arranged in the second cylindrical counter bore, the lower part of the second locking member 13 is cylindrical, and the upper part of the second locking member is square; a second locking hole is formed in the top of the second accommodating cavity 9, the outer wall of the lower portion of the second locking part 13 is in threaded connection with the inner wall of the second cylindrical counter bore, and the upper portion of the second locking part 13 is in sliding insertion connection with the second locking hole;

no. two lockholes run through revolving stage 7 and layer board 6, and the upper portion of No. two retaining member 13 is provided with second fixed knot and constructs.

When the ladder suite 10 is rotated, the internal threads on the inner wall of the second cylindrical counter bore act on the external threads on the outer wall of the lower part of the second locking piece 13; the upper part of the second locking piece 13 is inserted into the second locking hole, so that the second locking piece 13 does not rotate along with the step kit 10; finally, under the effect of the internal thread on the inner wall of the second cylindrical counter bore and the external thread on the outer wall of the lower part of the second locking member 13, the upper part of the second locking member 13 is driven to move towards the supporting plate 6, the second fixing structure is driven to move upwards along, and the second fixing structure is utilized to pass through the second lock hole to fix the calibration structure.

As a further scheme of the present invention, a sliding cavity is formed at the upper part of the second locking member 13, the second fixing structure includes a second positioning member 20 in sliding fit with the sliding cavity, and a pressure spring 21 is arranged in the sliding cavity;

an opening is formed in the upper portion of the sliding cavity, the opening is smaller than the cross-sectional size of the sliding cavity, a sliding block is integrally arranged on the lower portion of the second positioning piece 20, the sliding block is in sliding fit with the inner wall of the sliding cavity, and the upper portion of the second positioning piece 20 penetrates through the opening and extends out of the sliding cavity;

one end of the pressure spring 21 is attached to the bottom of the sliding cavity, and the other end of the pressure spring is attached to the bottom surface of the sliding block.

In the process that the second locking piece 13 moves upwards, the second positioning piece 20 is driven to move upwards by the pressure spring 21; when the top of the second positioning piece 20 passes through the second lock hole and is abutted against the bottom of the disc-shaped block body 3 in the calibration structure, the second locking piece 13 continues to move upwards; because the top of the second positioning piece 20 is already abutted against the bottom surface of the disc-shaped block body 3, when the second locking piece 13 continues to move upwards, the sliding block at the lower part of the second positioning piece 20 extrudes the compression spring 21, so that the compression spring 21 is elastically deformed; elastic deformation occurs through the pressure spring 21 to increase the conflict force between the top of the second positioning piece 20 and the bottom surface of the disc-shaped block body 3, so that the friction force between the top of the second positioning piece 20 and the bottom surface of the disc-shaped block body 3 is increased, and the disc-shaped block body 3 is fixed.

As a further scheme of the present invention, the lower portions of both sides of the disc-shaped block 3 are provided with clamping pins 22, the both sides of the supporting plate 6 are provided with clamping grooves 23 along the length direction of the supporting plate 6, and the disc-shaped block 3 is movably disposed on the supporting plate 6 by the sliding clamping of the clamping pins 22 and the clamping grooves 23.

Utilize bayonet 22 and draw-in groove 23 slip block to make the disk block 3 can not separate with layer board 6, and draw-in groove 23 sets up along the length direction of layer board 6, therefore disk block 3 and calibration structure can only be followed layer board 6 and at the radial activity of revolving stage 7.

As a further scheme of the present invention, a first bevel gear 24 is fixed on an outer wall of a lower portion of the ladder kit 10, the first bevel gear 24 is engaged with a second bevel gear 25, and a through shaft 26 is rotatably disposed on the model platform 1, one end of the through shaft 26 extends into the first cavity 8, and the other end extends out of the model platform 1;

the second bevel gear 25 is fixed at one end of the through shaft 26 extending into the first cavity 8, and the other end of the through shaft 26 is fixed with a knob 27.

In order to prevent the through shaft 26 from shifting in the axial direction thereof, a step is further provided at an intermediate position of the through shaft 26.

The through shaft 26 can be driven to rotate by rotating the knob 27, and the rotating through shaft 26 drives the second bevel gear 25 to rotate, so as to drive the first bevel gear 24 to rotate, and finally, the step kit 10 is driven to rotate.

Finally, the invention also discloses a method for calibrating the 3D visual camera and the mechanical arm by using the calibration model, which comprises the following steps:

firstly, calibrating the installation of a model, and sleeving a model installation part on a model body with a coaxial gap of a manifold on a welding gun tube; the supporting plate 6 is rotated around the Y direction to be parallel to the X direction by rotating the rotating platform 7; adjusting the calibration structure to move along the radial direction of the supporting plate 6 on the rotating table 7, so that the calibration structure and the welding gun barrel are located at the same position in the X direction; the rotational freedom of the manifold and the model mounting part 2 in the X direction, the moving freedom of the manifold and the model mounting part 2 in the X direction, the rotational freedom of the rotary table 7 in the Y direction and the moving freedom of the calibration structure on the pallet 6 are restrained by the locking mechanism; the 3D vision camera can identify the center spike calibration part 5 calibrated to the center of the calibration structure, and a welding gun tube on the mechanical arm and the 3D vision camera are ensured to be positioned under the same coordinate system, so that the 3D vision camera can guide the mechanical arm to move to perform welding;

setting an origin, capturing the central spine calibration part 5 in the calibration structure through the 3D visual camera, acquiring coordinate data of the central spine calibration part 5 in a coordinate system of the 3D visual camera, and initializing the acquired coordinate data to set the coordinate data as the origin of (0,0,0);

setting a track route, and selecting a plurality of continuous discrete typical point positions on a preset welding path, wherein the discrete typical point positions are matched with the characteristics of the preset welding path; (for example, if a preset welding path comprises two straight tracks and one curved track, and the curved track connects the first positions of the two straight tracks, when a discrete typical point position is selected, the initial point and the middle point of the curved track are considered emphatically, and as many point positions as possible are selected on the curved track as possible; counting coordinate data of the discrete typical point positions under a coordinate system of the 3D vision camera to form a data chain; sequentially inputting the formed data chain into a database according to the continuous point location distribution trend;

step four, data import, namely importing coordinate point bit data in the database into a 3D visual camera imaging system, generating a continuous three-dimensional track route in the imaging system according to the imported coordinate point bit data, and checking whether the presented three-dimensional track conforms to a preset welding path; if not, the method returns to step three to reselect the discrete typical point location or increase the number of the discrete typical point locations.

By the aid of the calibration method, on one hand, the central spine calibration part 5 in the calibration structure can be ensured to be positioned on the axis of the welding gun barrel, so that the welding gun barrel on the mechanical arm and the 3D vision camera are positioned in the same coordinate system, and guiding errors of the 3D vision camera are reduced; on the other hand, the position of the calibration structure can be finely adjusted after pre-assembly, so that the calibration structure is kept coaxial with the welding gun barrel, and the complicated debugging and installation process is simplified.

In addition, the presented three-dimensional track is closer to a preset welding path by selecting a plurality of continuous discrete typical point positions, and errors are reduced; the three-dimensional track path is viewed in advance in an imaging mode; when the presented path has larger deviation with the preset path, the presented path can be corrected in time and regenerated.

Because the three-dimensional track route presented by the invention is generated according to a plurality of continuous discrete typical point locations, the calculation amount of the point locations is smaller in the whole calibration process, the calculation load of a host is reduced, and the presentation rate of the path can be improved.

The above embodiments are exemplary rather than limiting, and embodiments of the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

Claims (2)

1. A calibration model for a welded 3D vision camera and a mechanical arm is characterized by comprising a calibration structure, a locking mechanism and a model body formed by a model mounting part (2) and a model platform (1);

the calibration structure is movably arranged above the rotating platform (7) along the radial direction of the rotating platform (7), and the rotating platform (7) is coaxially and rotationally matched with the model platform (1); a supporting plate (6) is fixedly arranged in the center of the top of the rotating table (7), the supporting plate (6) moves along the diameter direction of the rotating table (7), and the calibration structure is movably arranged on the supporting plate (6);

the axial direction of the model mounting part (2) and the manifold on the welding gun barrel forms an X direction; the axial direction of the model platform (1) forms a Y direction; a Z direction is formed in a direction perpendicular to the X direction and the Y direction;

the locking mechanism is used for restraining the freedom degree of rotation of the manifold and the model mounting part (2) in the X direction, the freedom degree of movement of the manifold and the model mounting part (2) in the X direction, the freedom degree of rotation of the rotating platform (7) in the Y direction and the freedom degree of movement of the calibration structure on the supporting plate (6);

the calibration structure comprises a disc-shaped block body (3), an outer edge shielding bulge (4) and a central spine calibration part (5); the outer edge shielding bulge (4) is arranged at the edge of the disc-shaped block body (3), and the central spine calibration part (5) is arranged at the circle center of the outer edge shielding bulge (4);

the model mounting part (2) is fixed with a manifold on the welding gun tube, and the manifold on the welding gun tube is vertically fixed with the welding gun tube; the model mounting part (2) is used for coaxially and fixedly mounting the model platform (1) on a welding gun tube of the mechanical arm;

a first containing cavity (8) is formed in the model body, a second containing cavity (9) is formed in the center of the bottom of the rotating table (7), the first containing cavity (8) and the second containing cavity (9) are coaxially arranged, and the top of the first containing cavity (8) is communicated with the bottom of the second containing cavity (9);

the locking mechanism comprises a step kit (10) rotatably arranged between a first containing cavity (8) and a second containing cavity (9), and the upper part and the lower part of the step kit (10) are respectively provided with a second cylindrical counter bore and a first cylindrical counter bore;

a first locking piece (11) is connected with the first cylindrical counter bore in an internal thread mode, the upper portion of the first locking piece (11) is cylindrical, and the lower portion of the first locking piece is square; the bottom of the first accommodating cavity (8) is provided with a square first locking hole (12) communicated with the interior of the model mounting part (2), the outer wall of the upper part of the first locking part (11) is in threaded connection with the inner wall of the first cylindrical counter bore, and the lower part of the first locking part (11) is in sliding insertion connection with the first locking hole (12);

a third locking piece (14) is further arranged in the first accommodating cavity (8), and inner threads matched with the outer threads on the outer wall of the upper part of the ladder sleeve (10) are arranged on the inner wall of the third locking piece (14);

a convex rib (15) is arranged at the outer edge of the third locking piece (14), a guide groove (16) is arranged on the inner wall of the first accommodating cavity (8), the guide groove (16) is in sliding embedded with the convex rib (15), and a first fixing structure is arranged on the upper edge of the third locking piece (14);

the first fixing structure comprises an elastic sheet (17) fixed on the upper edge of the third locking piece (14), a first positioning piece (18) fixed on the elastic sheet (17), and a supporting piece (19) fixed on the upper edge of the third locking piece (14);

a supporting hole which is matched with the supporting piece (19) in a sliding way is formed in the first positioning piece (18);

a second locking piece (13) is arranged in the second cylindrical counter bore, the lower part of the second locking piece (13) is cylindrical, and the upper part of the second locking piece is square; a second locking hole is formed in the top of the second accommodating cavity (9), the outer wall of the lower portion of the second locking piece (13) is in threaded connection with the inner wall of the second cylindrical counter bore, and the upper portion of the second locking piece (13) is in sliding insertion connection with the second locking hole;

the second lock hole penetrates through the rotating table (7) and the supporting plate (6), and a second fixing structure is arranged at the upper part of the second locking piece (13);

a sliding cavity is formed in the upper part of the second locking piece (13), the second fixing structure comprises a second positioning piece (20) in sliding fit with the sliding cavity, and a pressure spring (21) is arranged in the sliding cavity;

an opening is formed in the upper portion of the sliding cavity, the opening is smaller than the cross-sectional size of the sliding cavity, a sliding block is integrally arranged on the lower portion of the second positioning piece (20), the sliding block is in sliding fit with the inner wall of the sliding cavity, and the upper portion of the second positioning piece (20) penetrates through the opening and extends out of the sliding cavity;

one end of the pressure spring (21) is attached to the bottom of the sliding cavity, and the other end of the pressure spring is attached to the bottom surface of the sliding block;

clamping pins (22) are arranged on the lower portions of two sides of the disc-shaped block body (3), clamping grooves (23) are formed in two sides of the supporting plate (6) along the length direction of the supporting plate (6), and the disc-shaped block body (3) is movably arranged on the supporting plate (6) through the sliding clamping of the clamping pins (22) and the clamping grooves (23);

a first bevel gear (24) is fixed on the outer wall of the lower part of the ladder suite (10), the first bevel gear (24) is meshed with a second bevel gear (25), a penetrating shaft (26) is rotatably arranged on the model platform (1), one end of the penetrating shaft (26) extends into the first cavity (8), and the other end of the penetrating shaft extends out of the model platform (1);

the second bevel gear (25) is fixed at one end of the penetrating shaft (26) extending into the first cavity (8), and the other end of the penetrating shaft (26) is fixed with a knob (27).

2. A method for calibrating a 3D vision camera to a robotic arm using the calibration model of claim 1, comprising the steps of:

firstly, calibrating the installation of a model, and sleeving a model installation part on a model body with a coaxial gap of a manifold on a welding gun tube; rotating the rotating table to enable the supporting plate to rotate around the Y direction to be parallel to the X direction; adjusting the calibration structure to move along the radial direction of the supporting plate on the rotating table, so that the calibration structure and the welding gun barrel are located at the same position in the X direction; the rotation freedom degree of the manifold and the model mounting part in the X direction, the movement freedom degree of the manifold and the model mounting part in the X direction, the rotation freedom degree of the rotating platform in the Y direction and the movement freedom degree of the calibration structure on the supporting plate are restrained by utilizing a locking mechanism; the 3D vision camera can identify a central spine calibration part calibrated to the center of the calibration structure, and a welding gun tube on the mechanical arm and the 3D vision camera are ensured to be positioned under the same coordinate system;

setting an origin, capturing a central spine calibration part in the calibration structure through a 3D visual camera, acquiring coordinate data of the central spine calibration part in a coordinate system of the 3D visual camera, and initializing the acquired coordinate data to set the coordinate data as the origin of (0,0,0);

setting a track route, and selecting a plurality of continuous discrete typical point positions on a preset welding path, wherein the discrete typical point positions are matched with the characteristics of the preset welding path; counting coordinate data of the discrete typical point positions in a coordinate system of the 3D vision camera to form a data chain; sequentially inputting the formed data chain into a database according to the continuous point location distribution trend;

and step four, data import, namely importing coordinate point data in the database into a 3D vision camera imaging system, generating a continuous three-dimensional track route in the imaging system according to the imported coordinate point data, and checking whether the presented three-dimensional track is consistent with a preset welding path.

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