A method, system and apparatus for position calibration of a placement head

Abstract

The embodiment of the application discloses a position calibration method, system and device of a mounting head, the position calibration method comprises the following steps: acquiring standard center axis position data of a rotating shaft of the mounting head; replacing internal parts of the mounting head; acquiring center axis position data of the rotating shaft of the mounting head after the parts are replaced; calculating deviation of the center axis position data and the standard center axis position data, and if the deviation exceeds a preset allowable range, adjusting the mounting position of the mounting head on its track until the deviation meets the preset allowable range. The technical scheme provided by the embodiment of the application realizes quick and accurate calibration of the position of the mounting head.

Description

Technical Field

[0001] This invention relates to the field of placement head technology, and more particularly to a placement head position calibration method, system, and apparatus. Background Technology

[0002] SMT (Surface Mount Technology) is an assembly technology that allows surface-mount components or miniature components suitable for surface mounting to be directly mounted and soldered onto specified locations on the surface of a printed circuit board or other substrate without drilling through holes. The placement head is the core actuator of an SMT placement machine, responsible for picking up electronic components under program control and precisely placing them onto predefined pads on the PCB. The placement head typically needs to operate at high speeds and maintain high positional accuracy in both its track extension direction and the rotation direction of its axis.

[0003] The placement head moves using its track. As a key guiding component of the placement head, the track experiences increased resistance after prolonged high-speed operation due to friction and wear, affecting the placement head's movement accuracy and placement quality. In such cases, the track needs to be replaced. After replacement, it is crucial to ensure that the new track's trajectory matches the original center axis of the placement head's rotation. Otherwise, the placement head's movement in the rotation axis direction will deviate from the original trajectory, severely impacting placement accuracy.

[0004] In existing technologies, when an SMT placement head needs repair or calibration, the placement head typically picks up a calibration nozzle and moves it above the fixed camera's field of view. The placement head's rotation axis is then controlled to rotate every 5° from 0° to 360°. The coordinates of two markers on the calibration nozzle in the fixed camera's coordinate system are recorded after each rotation. The angle between the line connecting the two markers and the x-axis of the fixed camera's coordinate system is calculated. Then, based on the known rotation angle relationship between the fixed camera's coordinate system and the placement machine's coordinate system, the angle between the line connecting the markers and the x-axis of the machine's coordinate system is calculated. Finally, this measured angle is subtracted from the actual rotation angle of the rotation axis to obtain the rotational offset of the rotation axis at different rotation angles. This measurement process is cumbersome, time-consuming, and only provides the rotational offset of the rotation axis at a single stroke position, failing to measure the deviation of the rotation axis's central axis along the track's travel distance. When the placement head's trajectory deviates due to track replacement or long-term use, the above method cannot effectively identify and calibrate this deviation.

[0005] Therefore, how to quickly and accurately calibrate the position of the placement head has become a technical problem that urgently needs to be solved by those in the field. Summary of the Invention

[0006] This invention provides a method, system, and apparatus for calibrating the position of a placement head, so as to quickly and accurately calibrate the position of the placement head.

[0007] According to one aspect of the present invention, a method for calibrating the position of a mounting head is provided, comprising: Obtain the standard center axis position data of the rotation axis of the placement head; Replace the internal parts of the placement head; Obtain the center axis position data of the rotation axis of the mounting head after the part is replaced; Calculate the deviation between the center axis position data and the standard center axis position data. If the deviation exceeds the preset allowable range, adjust the installation position of the mounting head on its track until the deviation meets the preset allowable range.

[0008] Optionally, the standard center axis position data and the method for obtaining the center axis position data include: The coordinates of the positioning target point at at least three non-collinear positions during the rotation of the rotating axis of the mounting head are obtained, wherein the at least three non-collinear positions are located on the same plane and the plane is perpendicular to the central axis of the rotating axis; Calculate the center coordinates of the rotation axis at the current travel position based on the target point coordinates at the at least three non-collinear positions; The mounting head is controlled to move along its track to multiple different travel positions, and the steps of obtaining target point coordinates and calculating center coordinates are repeated at each travel position to obtain the center coordinates of the rotation axis corresponding to each travel position. Based on the center coordinates of the rotating shaft corresponding to multiple different stroke positions, the fitting result of the center axis of the rotating shaft is obtained; wherein, the fitting result of the center axis obtained by the above method before the internal parts are replaced is used as the standard center axis position data, and the fitting result of the center axis obtained by the above method after the internal parts are replaced is used as the center axis position data.

[0009] Optionally, obtaining the target coordinates at at least three non-collinear positions of the positioning target during the rotation of the mounting head's rotation axis includes: Acquire target point images at at least three different rotation angles along the rotation axis; Based on the target image, determine the target coordinates of the positioning target at each rotation angle.

[0010] Optionally, acquiring the target point image at at least three different rotation angles along the rotation axis includes: The target image of the positioning target point is acquired by a vision system at at least three different rotation angles on the rotation axis; And / or, the calculation of the center coordinates of the rotation axis at the current travel position based on the target coordinates at the at least three non-collinear positions includes: Based on the target coordinates at at least three different rotation angle positions, the center coordinates of the rotation axis at the current travel position are calculated using the three-point circle method.

[0011] Optionally, while controlling the placement head to move along its track to multiple different travel positions, the method further includes: The vision system is controlled to move synchronously with the mounting head so that the positioning target point is within the field of view of the vision system.

[0012] Optionally, controlling the vision system to move synchronously with the placement head includes: The vision system is controlled to have the same displacement and the same direction of movement as the mounting head, and the mounting head stops at each preset position simultaneously, so that the vision system can acquire images of the positioning target point during the period when the mounting head stops.

[0013] Optionally, the positioning target point is set on the positioning fixture, and the positioning fixture is fixed to the mounting head; The positioning fixture includes a positioning target and a base. The positioning target is a marked point set on the surface of the positioning target. The base can be adsorbed and fixed on the suction head seat of the mounting head.

[0014] According to another aspect of the present invention, a placement head position calibration system is provided, comprising: The acquisition module is used to acquire the standard center axis position data of the rotation axis of the placement head, as well as the center axis position data of the rotation axis of the placement head after the parts have been replaced. The calculation module is used to calculate the deviation between the center axis position data and the standard center axis position data; An adjustment module is used to adjust the mounting position of the mounting head on its track when the deviation exceeds a preset allowable range, until the deviation meets the preset allowable range.

[0015] According to another aspect of the present invention, a mounting head position calibration device is provided, comprising: A positioning fixture is fixed to the placement head and rotates synchronously with the rotation axis of the placement head; the positioning fixture includes a positioning target. A vision system is used to acquire target point images of the positioning target. A drive controller is used to control the rotation of the rotation axis of the placement head and to control the movement of the placement head along the track in the direction of the rotation axis; A positioning adjustment mechanism is used to adjust the mounting position of the rotating shaft of the mounting head on the track; The position calibration system for the mounting head as described in any embodiment of the present invention is communicatively connected to the vision system, the drive controller, and the positioning adjustment mechanism.

[0016] Optionally, the vision system includes a telecentric lens, a camera, and a light source; the drive controller is also used to control the vision system and the placement head to move synchronously in the direction of rotation via a stepper motor slide on which the vision system is mounted.

[0017] The technical solution provided by this invention, by pre-acquiring the standard center axis position data of the placement head's rotation axis in a good condition, serves as a benchmark for subsequent calibration, thus fully characterizing the standard three-dimensional spatial position of the placement head at different travel positions on the track. After replacing internal parts of the placement head, such as after replacing the track, the actual center axis position data of the rotation axis is acquired again, and the two sets of data are compared. The installation position of the placement head on its track is adjusted until the deviation meets the preset allowable range, thereby achieving calibration of the placement head position. This ensures that the running trajectory of the replaced placement head is consistent with the original trajectory before replacement, achieving rapid and accurate calibration, effectively reducing maintenance costs, and simultaneously ensuring the movement accuracy and placement quality of the placement head after track replacement.

[0018] It should be understood that the description in this section is not intended to identify key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the embodiments of the present invention. Other features of the embodiments of the present invention will become readily apparent from the following description. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart of a method for calibrating the position of a mounting head according to an embodiment of the present invention; Figure 2 This is a flowchart of another method for calibrating the position of the mounting head provided in an embodiment of the present invention; Figure 3 This is a flowchart of another method for calibrating the position of the mounting head provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a positioning fixture provided in an embodiment of the present invention; Figure 5This is a schematic diagram of the structure of a mounting head suction cup holder provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure after the positioning fixture is fixed on the suction head seat of the mounting head according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of a mounting head position calibration device provided in an embodiment of the present invention; Figure 8 This is a schematic diagram illustrating the calculation of the center coordinates of a rotation axis based on the three-point circle method provided in an embodiment of the present invention; Figure 9 This is a flowchart of another method for calibrating the position of the mounting head provided in an embodiment of the present invention; Figure 10 This is a flowchart of another method for calibrating the position of the mounting head provided in an embodiment of the present invention; Figure 11 This is a structural block diagram of another mounting head position calibration system provided in an embodiment of the present invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the embodiments of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the embodiments of the present invention.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of the embodiments of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0023] This invention provides a method for calibrating the position of a mounting head. Figure 1 This is a flowchart of a placement head position calibration method provided in an embodiment of the present invention, see reference. Figure 1 The placement head position calibration methods include: S110. Obtain the standard center axis position data of the mounting head's rotation axis.

[0024] Specifically, during operation, the placement head's rotation axis moves up and down along the track, and the trajectory formed by the center of the rotation axis in space is a straight line. This straight line reflects the current installation posture of the placement head and the guiding direction of the track. Standard center axis position data refers to the position data of the center of its rotation axis in space when the placement head is in a properly installed state. It characterizes the spatial posture of the rotation axis during its movement along the track, thus representing the standard three-dimensional spatial position of the placement head at different travel positions along the track. The rotation axis is mounted on the track and can move along it; the placement head is fixed to the rotation axis and can rotate with the rotation axis and move along the track.

[0025] With the placement head in a properly installed state, such as before replacing internal components, the coordinates of the rotation axis center are acquired at multiple different positions along the track. Based on these coordinates, the standard center axis position data of the rotation axis is obtained. For example, multiple positions can be evenly selected throughout the entire travel range of the placement head along the track. The center coordinates of the rotation axis are measured at each position, and a standard trajectory of the rotation axis center axis in space is obtained through linear fitting. The standard center axis position data of the rotation axis is then obtained based on this fitted trajectory. This standard center axis position data serves as a reference for subsequent calibration.

[0026] S120, Replace the internal parts of the placement head.

[0027] Specifically, internal components of the placement head include, for example, the track. The track is a key guiding component for the vertical movement of the placement head. During long-term high-speed operation, the track will experience increased resistance due to friction and wear, affecting the movement accuracy and placement quality of the placement head. In this case, the track needs to be replaced. During replacement, the old track is removed from the placement head base, and the new track is installed. Because the installation position of the new track may deviate from the original track, calibration is required after replacement.

[0028] S130. Obtain the center axis position data of the mounting head's rotation axis after the part has been replaced.

[0029] Specifically, after the part replacement is completed, the position data of the center axis of the rotating shaft of the placement head is remeasured using the same measurement method as in step S110. For example, multiple positions can be evenly selected within the entire stroke range of the placement head moving along the track, and the center coordinates of the rotating shaft can be measured at each position. The actual trajectory of the center axis of the rotating shaft in space is obtained through linear fitting, and the actual center axis position data of the rotating shaft is obtained based on the fitted actual trajectory of the center axis of the rotating shaft in space. This standard center axis position data serves as the judgment data for whether the position of the placement head needs to be calibrated. It should be noted that the multiple positions selected when obtaining the standard center axis position data can be exactly the same, partially the same, or completely different from the multiple positions selected when obtaining the center axis position data after the part replacement.

[0030] S140. Calculate the deviation between the center axis position data and the standard center axis position data. If the deviation exceeds the preset allowable range, adjust the installation position of the mounting head on its track until the deviation meets the preset allowable range.

[0031] Specifically, the center axis position data obtained in step S130 after the part replacement is compared with the standard center axis position data obtained in step S110. The standard trajectory line determined by the standard center axis position data is compared with the actual trajectory line determined by the center axis position data after the part replacement. Since both lines represent the trajectory of the center axis of the rotating shaft in space, the deviation can include the parallel offset and tilt angle deviation of the two lines in the direction perpendicular to the center axis. If the two lines completely overlap, it indicates that the installation position of the new track is consistent with the original position of the old track, and no further adjustment is needed. If there is a deviation between the two lines, and the deviation exceeds the preset allowable range, the installation position of the mounting head on the track needs to be fine-tuned using the adjustment mechanism. After each adjustment, the current center axis position data is measured again according to the method in step S130 and compared with the standard data until the deviation of the two lines meets the preset allowable range, completing the calibration. At this point, the running trajectory of the replaced track is consistent with the original trajectory before replacement, and the positional accuracy of the mounting head is restored. The preset allowable range can be set according to actual needs, such as a preset allowable range of less than or equal to 8 micrometers, less than or equal to 7 micrometers, less than or equal to 5 micrometers, less than or equal to 4 micrometers, or less than or equal to 1 micrometer.

[0032] The technical solution provided by this invention, by pre-acquiring the standard center axis position data of the placement head's rotation axis in a good condition, serves as a benchmark for subsequent calibration, thus fully characterizing the standard three-dimensional spatial position of the placement head at different travel positions on the track. After replacing internal parts of the placement head, such as after replacing the track, the actual center axis position data of the rotation axis is acquired again, and the two sets of data are compared. The installation position of the placement head on its track is adjusted until the deviation meets the preset allowable range, thereby achieving calibration of the placement head position. This ensures that the running trajectory of the replaced placement head is consistent with the original trajectory before replacement, achieving rapid and accurate calibration, effectively reducing maintenance costs, and simultaneously ensuring the movement accuracy and placement quality of the placement head after track replacement.

[0033] Figure 2 This is a flowchart of another placement head position calibration method provided in an embodiment of the present invention, see reference. Figure 2 The placement head position calibration methods include: S210. Obtain the standard center axis position data of the mounting head's rotation axis.

[0034] S220, Replace the internal parts of the placement head.

[0035] S230. Obtain the coordinates of the positioning target at at least three non-collinear positions during the rotation of the mounting head's rotation axis. The at least three non-collinear positions are located on the same plane, and the plane is perpendicular to the central axis of the rotation axis.

[0036] S240. Calculate the center coordinates of the rotation axis at the current travel position based on the target coordinates at at least three non-collinear positions; wherein the positioning target is fixed on the pick-up head of the placement head and rotates synchronously with the rotation axis of the placement head.

[0037] Specifically, the positioning target is fixed on the suction head holder of the placement head, allowing it to rotate synchronously with the rotation axis of the placement head. During the rotation of the axis, when the positioning target reaches a certain angular position, a target image of the positioning target can be acquired through a vision system, and then the target coordinates corresponding to that angular position can be obtained based on the target image. In other embodiments of the present invention, other measurement methods can also be used to obtain the target coordinates of the positioning target, such as using a laser displacement sensor to scan the position of the positioning target to obtain coordinate data.

[0038] The rotation axis is controlled to sequentially rotate to multiple different angular positions, such as the initial position, the position after rotating 120 degrees, and the position after rotating 240 degrees. At each angular position, the target point coordinates are acquired, resulting in at least three non-collinear target point coordinates. Since these target point coordinates all lie on the same circular trajectory centered on the rotation axis, the center coordinates of this circle can be determined using the coordinates of at least three non-collinear target points. These center coordinates are the center coordinates of the rotation axis at the current travel position. It is understood that the number of rotation angular positions is not limited to three; four or more can be used. More points result in higher accuracy of the fitted circle center, but the computational load also increases accordingly.

[0039] S250: Control the placement head to move along the track to multiple different travel positions, and repeat the steps of obtaining target point coordinates and calculating center coordinates at each travel position to obtain the center coordinates of the rotation axis corresponding to each travel position.

[0040] Specifically, the track is fixed to the base of the placement head, and the slider is mounted on the track and can slide along it. The rotating shaft is fixed to the slider, and the suction head holder of the placement head is fixed to the rotating shaft and can rotate with the rotating shaft. The positioning target point is set on the suction head holder. The slider is driven by a drive motor to move along the track, and the slider drives the rotating shaft and the suction head holder fixed on it to move synchronously, thereby changing the position of the placement head.

[0041] The slider can be controlled to move sequentially to multiple preset positions from the starting end of the track with a set step size. At each position, the slider pauses its movement, the entire placement head remains stable, and then, following steps S210 and S220, the suction head holder is controlled to rotate with the rotation axis, and the target point coordinates of the positioning target are collected at at least three non-collinear angular positions, thereby calculating the center coordinates of the rotation axis of the placement head at multiple different stroke positions.

[0042] Because the track has a certain straightness error during installation, and the slider may also have a slight offset as it moves along the track, the central spatial position of the rotating shaft will deviate as the stroke position changes. Therefore, independently measuring the center coordinates of the rotating shaft at each stroke position can completely obtain the actual trajectory of the rotating shaft's center in space. The selected stroke positions should cover the entire stroke of the mounting head during normal operation. The number of stroke positions can be determined according to accuracy requirements; more positions result in a more accurate fitted center axis, but the measurement time will also increase accordingly. In this embodiment of the invention, the number of stroke positions is at least two.

[0043] S260. Based on the center coordinates of the rotating shaft corresponding to multiple different stroke positions, obtain the actual center axis fitting result of the rotating shaft, and use the actual center axis fitting result of the rotating shaft as the center axis position data.

[0044] Specifically, when the placement head moves along the track in the direction of the rotation axis, the theoretical center trajectory of the rotation axis should be a straight line in space. The center coordinates of the rotation axis at multiple different travel positions can be used as discrete points. A straight line fitting algorithm can be used to fit these discrete points to a straight line, which is the actual center axis of the rotation axis in the current state of the placement head. The actual center axis reflects the current installation accuracy of the placement head on the track and the guiding accuracy of the track.

[0045] S270. Based on the deviation between the center axis position data and the standard center axis position data, adjust the mounting position of the placement head's rotation axis on the track to calibrate the placement head's position.

[0046] Specifically, based on the calculated deviation, the mounting position of the placement head's rotating axis on the track is adjusted using an adjustment mechanism. A fine-tuning mechanism can be used to change the position of the rotating axis relative to the slider in the direction perpendicular to the rotating axis, thereby restoring the rotating axis's orientation to the state corresponding to the standard central axis.

[0047] After calibration, steps S230 to S270 can be performed again to remeasure the actual center axis position data of the rotating shaft and verify whether its deviation from the standard center axis position data of the rotating shaft is within the allowable range. If the deviation is not within the allowable range, the above adjustment steps are repeated until the requirements are met.

[0048] The mounting head position calibration method provided in this embodiment of the invention obtains the target coordinates at at least three non-collinear positions during the rotation of the mounting head rotation axis, and calculates the center coordinates of the rotation axis based on the target coordinates at the three non-collinear positions. It also obtains the fitting result of the actual center axis of the rotation axis by fitting the center coordinates of the rotation axis at multiple different stroke positions, thereby determining the position data of the actual center axis of the rotation axis.

[0049] Furthermore, the specific steps for obtaining the standard center axis position data of the placement head's rotation axis may include: before replacing the internal parts of the placement head, obtaining the target point coordinates at at least three non-collinear positions during the rotation of the placement head's rotation axis, wherein the at least three non-collinear positions are located on the same plane, and the plane is perpendicular to the rotation axis; calculating the center coordinates of the rotation axis at the current stroke position based on the target point coordinates at the at least three non-collinear positions; controlling the placement head to move along its track to multiple different stroke positions, and repeating the above steps of obtaining the target point coordinates and calculating the center coordinates at each stroke position to obtain the center coordinates of the rotation axis corresponding to each stroke position; obtaining the center axis fitting result of the rotation axis based on the center coordinates of the rotation axis corresponding to multiple different stroke positions. In other words, the center axis fitting result obtained by the above method before replacing the internal parts is used as the standard center axis position data.

[0050] Figure 3 This is a flowchart of another placement head position calibration method provided in an embodiment of the present invention, see reference. Figure 3 The placement head position calibration methods include: S310. Obtain the standard center axis position data of the mounting head's rotation axis.

[0051] S320, Replace the internal parts of the placement head.

[0052] S330. Obtain target point images at at least three different rotation angles of the rotation axis; wherein the target point is set on the positioning fixture, and the positioning fixture is fixed on the placement head; the positioning fixture includes a positioning target and a base, the positioning target is a mark point set on the surface of the positioning target, and the base can be adsorbed and fixed on the suction head seat of the placement head.

[0053] For details, please refer to Figures 4-6 The positioning fixture 80 comprises two parts: a disc-shaped positioning target 81 and a base 82. The surface of the positioning target 81 is provided with markings that can be identified by a vision system; these markings are the positioning target points A. The base 82 of the positioning fixture 80 is designed to be fixed to the suction head seat 40 of the placement head, forming a rigid connection between the positioning fixture 80 and the suction head seat 40. This ensures that the relative position between the positioning target point A and the suction head seat 40 remains consistent during the rotation of the rotating shaft. The positioning fixture 80 can be connected to the suction head seat 40 via magnetic adsorption or other detachable fixing methods, ensuring that it will not loosen or shift during subsequent rotation. In this embodiment, the positioning fixture 80 is fixed to the suction head seat 40 via magnetic adsorption. This eliminates the need for mechanical locking structures such as screws or clips, facilitating assembly and disassembly and shortening calibration operation time. Furthermore, it prevents scratches or wear on the surface of the suction head seat 40 due to repeated assembly and disassembly.

[0054] The positioning target point A can be an etched mark on the surface of the positioning target 81, or a colored mark on the surface of the positioning target 81. For example, the positioning target 81 is a white ceramic sheet, and the positioning target point A is a black dot with a diameter of 100 micrometers made at the center of the white ceramic sheet surface. The positioning target 81 is installed inside a steel base and can be attracted by a magnet.

[0055] Further reference Figure 7 The vision system 60 can acquire images of the positioning target point A at at least three different rotation angles along the rotation axis. The vision system 60 includes a telecentric lens, a camera, and a light source. The telecentric lens works in conjunction with the camera to acquire images of the positioning target point A. The telecentric lens is a specially designed optical lens characterized by its magnification remaining constant with respect to the object distance within a certain range, and exhibiting extremely low perspective distortion. During calibration measurements, as the mounting head moves along the rotation axis of the track, the distance between the positioning target point A and the lens may change slightly. If a conventional lens is used, this change in object distance would alter the magnification, introducing measurement errors. The telecentric lens effectively eliminates this effect, ensuring that the target point images acquired at different travel positions have the same magnification, and the coordinate measurement results are unaffected by changes in object distance. The light source provides uniform and stable illumination for target imaging. By appropriately selecting the light source type and illumination angle, sufficient grayscale difference can be created between the marked points on the surface of the positioning target 81 and the background, facilitating accurate extraction of the edge and center positions of the marked points by subsequent image processing algorithms.

[0056] S340. Based on the target image, determine the target coordinates at each rotation angle.

[0057] Specifically, after obtaining the target images, each image is analyzed and processed using image processing algorithms. Image processing mainly includes operations such as grayscale conversion, binarization, edge detection, and contour extraction of the target images. The marker points on the surface of the positioning target 81 are identified from the image, and the position of the marker point in the image coordinate system is calculated, thereby obtaining the target coordinates of the positioning target at each rotation angle.

[0058] S350. Calculate the center coordinates of the rotation axis at the current travel position based on the target coordinates at each rotation angle.

[0059] Specifically, the step of calculating the center coordinates of the rotation axis at the current travel position based on the target coordinates at each rotation angle may include: calculating the center coordinates of the rotation axis at the current travel position based on the three-point circle method, according to the target coordinates at at least three different rotation angle positions.

[0060] Since the positioning target is fixed on the suction head and rotates synchronously with the rotation axis, its spatial position at different rotation angles lies on the same circle centered on the rotation axis. Therefore, by taking the target coordinates obtained at at least three different rotation angles as three points on the circle, the center coordinates of this circle can be calculated using the three-point circle determination method. This center is the center coordinate of the rotation axis at its current travel position. It should be noted that the principle of the three-point circle determination method is: given three non-collinear points on a plane, a circle can be uniquely determined, and the center of this circle is the center of the circumference containing the three points. In specific calculations, the coordinates of the three target points are substituted into the equation of the circle, and the center coordinates are solved by solving the simultaneous equations. (Reference) Figure 8 The vision system acquires the coordinates of three target points at three different rotation angles, namely A1(x1, y1), A2(x2, y2), and A3(x3, y3). Since the three points lie on the same circle, the distances from the center O of the circle to the three points are equal, all equal to the radius r. According to the equation of the circle (xa)... 2 +(yb) 2 =r 2 Substitute the coordinates of the three points into the equation to obtain the specific values ​​of a and b, thereby obtaining the coordinates of the center O, which is the center coordinate of the rotation axis at the current travel position.

[0061] S360: Control the placement head to move along the track to multiple different travel positions, and repeat the steps of obtaining target point coordinates and calculating center coordinates at each travel position to obtain the center coordinates of the rotation axis corresponding to each travel position.

[0062] S370. Based on the center coordinates of the rotating shaft corresponding to multiple different stroke positions, obtain the actual center axis fitting result of the rotating shaft, and use the actual center axis fitting result of the rotating shaft as the center axis position data.

[0063] S380. Based on the deviation between the center axis position data and the standard center axis position data, adjust the mounting position of the placement head's rotation axis on the track to calibrate the placement head's position.

[0064] For details, please refer to Figure 7The mounting position of the rotating shaft 30 of the mounting head on the track can be adjusted by the positioning adjustment mechanism 50. The positioning adjustment mechanism 50 includes a precision electric slide 51 and a clamp 52. One end of the clamp 52 holds the rotating shaft 30, and the other end is fixedly connected to the precision electric slide 51 by a fastening screw. During adjustment, the precision electric slide 51 can drive the clamp 52 to make a small displacement in a direction perpendicular to the rotating shaft (z1 direction). The clamp 52 drives the rotating shaft 30 to move synchronously, thereby changing the mounting position of the rotating shaft 30 on the track slider. After adjustment, tighten the fastening screw between the rotating shaft 30 and the track slider to complete the fixation. In another embodiment, the end of the clamp 52 away from the rotating shaft 30 is connected to the precision electric slide 51 through a fastening screw and a long screw hole. After loosening the fastening screw, the clamp 52 can be manually moved slightly in a direction perpendicular to the rotating shaft 30 along the extension direction of the long screw hole, thereby driving the rotating shaft 30 to move synchronously. After adjustment, tighten the fastening screw again to complete the fixation.

[0065] The technical solution provided by this invention, based on the above embodiments, ensures a rigid connection and consistent repeated installation between the positioning target point and the rotating axis by magnetically attaching the positioning fixture with marked points to the suction head base of the placement head. The magnetic attachment method is convenient for installation and removal without damaging the suction head base. Furthermore, a vision system is used to acquire target point images of the rotating axis at different angles and extract the target point coordinates. The center of the rotating axis is calculated using the three-point circle method, achieving high-precision center positioning and avoiding errors caused by manual measurement. Therefore, this method, without altering the original structure of the placement head, provides reliable rotating axis center coordinates with simple operation, offering an accurate measurement basis for subsequent linear fitting of multi-stroke positions and placement head position calibration. It also reduces the difficulty of on-site operation and reliance on original manufacturer calibration services.

[0066] Figure 9 This is a flowchart of another placement head position calibration method provided in an embodiment of the present invention, see reference. Figure 9 The placement head position calibration methods include: S410. Obtain the standard center axis position data of the mounting head's rotation axis.

[0067] S420, Replace the internal parts of the placement head.

[0068] S430. Acquire target point images at at least three different rotation angles along the rotation axis using a vision system; wherein the target point is set on a positioning fixture, and the positioning fixture is fixed to the placement head; the positioning fixture includes a positioning target and a base, the target point is a marker point set on the surface of the positioning target, and the base can be magnetically fixed to the suction head seat of the placement head; the vision system includes a telecentric lens, a camera, and a light source.

[0069] S440. Based on the target image, determine the target coordinates at each rotation angle.

[0070] S450. Calculate the center coordinates of the rotation axis at the current travel position based on the target coordinates at each rotation angle.

[0071] S460: While controlling the placement head to move along the track to multiple different travel positions, control the vision system to move synchronously with the placement head so that the positioning target point is within the field of view of the vision system. Repeat the steps of obtaining the target point coordinates and calculating the center coordinates at each travel position to obtain the center coordinates of the rotation axis corresponding to each travel position.

[0072] The step of controlling the vision system and the placement head to move synchronously includes: controlling the vision system and the placement head to have the same displacement and the same direction of movement, and stopping at each preset stroke position when the placement head moves, so that the vision system can acquire images of the positioning target points during the placement head's stop.

[0073] S470. Based on the center coordinates of the rotating shaft corresponding to multiple different stroke positions, obtain the actual center axis fitting result of the rotating shaft, and use the actual center axis fitting result of the rotating shaft as the center axis position data.

[0074] S480. Based on the deviation between the center axis position data and the standard center axis position data, adjust the mounting position of the placement head's rotation axis on the track to calibrate the placement head's position.

[0075] The technical solution provided in this invention, based on the above embodiments, controls the vision system to move synchronously with the placement head as it moves along the track in the direction of rotation. Although the telecentric lens has a constant magnification within a certain object distance range, its field of view and depth of field are still limited. If the lens remains stationary, when the placement head moves to the upper or lower limits of its stroke, the target point may be outside the lens's field of view, resulting in unclear imaging. Therefore, the telecentric lens is mounted on a precision stepper motor slide, which can also move along the direction of rotation. During the movement of the placement head along the track to different stroke positions, the drive controller simultaneously controls the precision stepper motor slide to move the telecentric lens synchronously with the placement head. Specifically, the telecentric lens and the placement head are controlled to have the same displacement and the same direction of movement in the direction of rotation, ensuring that the telecentric lens always tracks the movement of the target point and that the target point remains in the center of the telecentric lens's field of view, maintaining clear imaging. Whenever the placement head reaches a preset travel position and pauses, the precision stepper motorized slide also stops moving synchronously, and the vision system then acquires an image of the target point at that position. Through this synchronous control method, only one focusing is required at the initial stage to obtain a clear target point image at each travel position, eliminating the need to readjust the lens focus or alignment at each travel position. This improves measurement efficiency and ensures the consistency of image acquisition.

[0076] Based on the above embodiments, optionally, the internal component of the placement head to be replaced is the track of the placement head. The standard center axis position data of the rotation axis is the center axis position data of the rotation axis of the placement head before the track is replaced, and the center axis position data of the rotation axis is the actual center axis position data of the placement head after the track is replaced. Figure 10 This is a flowchart of another placement head position calibration method provided in an embodiment of the present invention, see reference. Figure 10 The placement head position calibration methods include: S510. Before changing the track, fix the positioning target point on the suction head holder of the placement head, and control the placement head to move along the track to multiple different stroke positions; at each stroke position, control the rotation axis of the placement head to rotate, obtain the target point coordinates at at least three non-collinear positions during the rotation of the rotation axis, and calculate the rotation axis center coordinates corresponding to each stroke position based on the target point coordinates obtained at each stroke position; based on the rotation axis center coordinates corresponding to multiple different stroke positions, obtain the standard center axis position data of the rotation axis, which serves as the reference data for subsequent calibration.

[0077] S520. Remove the old track on the mounting head and replace it with a new track.

[0078] S530. After changing the track, fix the positioning target point on the suction head holder of the placement head, and control the placement head to move along the track to multiple different stroke positions; at each stroke position, control the rotation axis of the placement head to rotate, obtain the target point coordinates at at least three non-collinear positions during the rotation of the rotation axis, and calculate the rotation axis center coordinates corresponding to each stroke position based on the target point coordinates obtained at each stroke position; obtain the actual center axis position data of the rotation axis based on the rotation axis center coordinates corresponding to multiple different stroke positions.

[0079] S540. Compare the obtained actual center axis position data with the standard center axis position data and calculate the deviation between the two. Based on the deviation, adjust the installation position of the mounting head's rotating shaft on the track through the adjustment mechanism so that the actual center axis of the rotating shaft coincides with the standard center axis, thus completing the calibration of the mounting head position.

[0080] The above method first determines the standard center axis position data of the rotating shaft by measuring the center coordinates of the rotating shaft at multiple stroke positions before changing the track, and uses this data as a reference for calibration after track replacement. After track replacement, the center axis position data of the rotating shaft is obtained using the same measurement procedure. Based on the deviation between the standard center axis position data and the center axis position data of the rotating shaft after track replacement, the installation position of the rotating shaft on the track is directly adjusted until the deviation is within a preset range. This ensures that the running trajectory of the replaced track can be restored to the original reference, achieving precise calibration of the mounting head position.

[0081] This invention also provides a placement head position calibration system, with reference to... Figure 11 The placement head position calibration system includes: Module 1 is used to acquire the standard center axis position data of the rotation axis of the placement head, as well as the center axis position data of the rotation axis of the placement head after the parts have been replaced. Calculation module 2 is used to calculate the deviation between the center axis position data and the standard center axis position data; Adjustment module 3 is used to adjust the mounting position of the mounting head on its track when the deviation exceeds the preset allowable range, until the deviation meets the preset allowable range.

[0082] The placement head position calibration system provided in this embodiment of the invention can execute the placement head position calibration method provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the method.

[0083] refer to Figure 7 This invention also provides a mounting head position calibration device, comprising: Mounting bracket 10 is used to fix the mounting head to the platform base 20; The positioning fixture 80 is fixed on the placement head and rotates synchronously with the rotation axis of the placement head. The positioning fixture 80 includes a positioning target 81 and a base 82. The positioning target 81 has a positioning target point A on its surface, and the base 82 can be adsorbed and fixed on the suction head seat 40 of the placement head. Vision system 60 is used to acquire target images for locating target point A; The drive controller is used to control the rotation of the mounting head's rotating axis and to control the movement of the mounting head along the track in the direction of the rotating axis. The positioning adjustment mechanism 50 is used to adjust the mounting position of the rotating shaft 30 of the placement head on the track; As described in any embodiment of the present invention, the position calibration system for the mounting head includes a system calibration device connected to a vision system 60, a drive controller, and a positioning adjustment mechanism 50.

[0084] Specifically, the placement head position calibration system includes a mounting base 10, a positioning fixture 80, a vision system 60, a drive controller, a positioning adjustment mechanism 50, and a calibration control device. The mounting base 10 is used to fix the placement head to the platform base 20. The platform base 20 is preferably made of marble to provide a stable mounting reference and good vibration isolation, ensuring the stability of the placement head's position during measurement. The positioning fixture 80 includes a positioning target 81 and a base 82. The positioning target 81 has a positioning target point A on its surface. The base 82 is designed to be magnetically attached to the suction head seat 40 of the placement head. Thus, after the positioning fixture 80 is fixed to the placement head, the positioning target point A rotates synchronously with the rotation axis of the placement head.

[0085] The vision system 60 includes a telecentric lens, an industrial camera, and a light source. It is used to acquire images of the target point A at different rotation angles, thereby extracting the target point coordinates through image processing. A drive controller is connected to the rotation axis drive motor of the placement head, controlling the rotation axis to rotate at a set angle and controlling the placement head to move along the track to various preset positions in the rotation axis direction. The industrial camera can be mounted at the rear end of the telecentric lens, with the optical axis of the telecentric lens parallel to the axis of rotation of the placement head, and the center of the telecentric lens's field of view aligned with the spatial area where the target point A is located as it rotates with the axis. The light source is mounted at the front or side of the telecentric lens, with its emission direction towards the location of the target point A. It provides uniform and stable illumination during image acquisition to ensure sufficient contrast between the mark of the target point A and the background, facilitating subsequent image processing algorithms to extract the target point coordinates.

[0086] The positioning and adjustment mechanism 50 includes a precision electric slide 51 and a clamp 52. One end of the clamp 52 holds the rotating shaft 30, and the other end is fixedly connected to the precision electric slide 51 via a fastening screw. During adjustment, the precision electric slide 51 drives the clamp 52 to make a slight displacement in a direction perpendicular to the rotating shaft. The clamp 52 drives the rotating shaft 30 to move synchronously, thereby changing the installation position of the rotating shaft 30 on the track slider. After adjustment, the fastening screw between the rotating shaft 30 and the track slider is tightened to complete the fixation. In another embodiment, the end of the clamp 52 away from the rotating shaft 30 is connected to the precision electric slide 51 via a fastening screw and a long screw hole. After loosening the fastening screw, the clamp 52 can be manually moved slightly in a direction perpendicular to the rotating shaft 30 along the extension direction of the long screw hole, thereby driving the rotating shaft 30 to move synchronously. After adjustment, the fastening screw is tightened again to complete the fixation. Both methods described above can achieve precise fine-tuning of the installation position of the rotating shaft 30. The former is suitable for automatic control scenarios, while the latter is suitable for scenarios requiring manual fine-tuning. The choice can be made according to actual needs. The calibration control system (e.g., an industrial computer) is connected to the vision system 60, the drive controller, and the positioning adjustment mechanism 50, respectively, and is used to execute the calibration method steps described in the foregoing embodiments. This includes receiving target point coordinate data fed back by the vision system 60, sending movement control commands to the drive controller, and sending adjustment commands to the positioning adjustment mechanism 50 based on the deviation between the actual center axis and the standard center axis, until the deviation between the actual center axis and the standard center axis meets the accuracy requirements.

[0087] Furthermore, the vision system 60 includes a telecentric lens, a camera, and a light source; the drive controller is also used to control the vision system 60 and the placement head to move synchronously in the rotation axis direction via a stepper motor slide 70 on which the vision system 60 is mounted. The rotation axis direction is parallel to direction z1.

[0088] The above system can autonomously complete the position calibration after the mounting head track is replaced. The entire measurement and adjustment process is automatically controlled by the calibration control device. Operators only need to complete the installation of the positioning fixture 80 and a simple start-up operation, which reduces the difficulty of on-site operation and improves calibration efficiency and accuracy.

[0089] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the embodiments of the present invention are not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for calibrating the position of a placement head, characterized in that, include: Obtain the standard center axis position data of the rotation axis of the placement head; Replace the internal parts of the placement head; Obtain the center axis position data of the rotation axis of the mounting head after the part is replaced; Calculate the deviation between the center axis position data and the standard center axis position data. If the deviation exceeds the preset allowable range, adjust the installation position of the mounting head on its track until the deviation meets the preset allowable range.

2. The method for calibrating the position of the placement head according to claim 1, characterized in that, The standard center axis position data and the method for obtaining the center axis position data include: The coordinates of the positioning target point at at least three non-collinear positions during the rotation of the rotation axis of the mounting head are obtained, wherein the at least three non-collinear positions are located on the same plane and the plane is perpendicular to the rotation axis; Calculate the center coordinates of the rotation axis of the mounting head at the current travel position based on the target point coordinates at the at least three non-collinear positions; The mounting head is controlled to move along its track to multiple different travel positions, and the steps of obtaining target point coordinates and calculating center coordinates are repeated at each travel position to obtain the center coordinates of the rotation axis corresponding to each travel position. Based on the center coordinates of the rotating shaft corresponding to multiple different stroke positions, the fitting result of the center axis of the rotating shaft is obtained; wherein, the fitting result of the center axis obtained before the internal parts are replaced is used as the standard center axis position data, and the fitting result of the center axis obtained after the internal parts are replaced is used as the center axis position data.

3. The method for calibrating the position of the placement head according to claim 2, characterized in that, The process of obtaining the coordinates of the positioning target point at at least three non-collinear positions during the rotation of the mounting head's rotation axis includes: Acquire target point images at at least three different rotation angles along the rotation axis; Based on the target image, determine the target coordinates of the positioning target at each rotation angle.

4. The method for calibrating the position of the placement head according to claim 3, characterized in that, The step of acquiring the target point image at at least three different rotation angles along the rotation axis includes: The target image of the positioning target point is acquired by a vision system at at least three different rotation angles on the rotation axis; And / or, the calculation of the center coordinates of the rotation axis at the current travel position based on the target coordinates at the at least three non-collinear positions includes: Based on the target coordinates at at least three different rotation angle positions, the center coordinates of the rotation axis at the current travel position are calculated using the three-point circle method.

5. The method for calibrating the position of the placement head according to claim 4, characterized in that, The method of controlling the placement head to move along its track to multiple different travel positions also includes: The vision system is controlled to move synchronously with the mounting head so that the positioning target point is within the field of view of the vision system.

6. The method for calibrating the position of the placement head according to claim 5, characterized in that, The control of the vision system to move synchronously with the placement head includes: The vision system is controlled to have the same displacement and the same direction of movement as the mounting head, and the mounting head stops at each preset position simultaneously, so that the vision system can acquire images of the positioning target point during the period when the mounting head stops.

7. The method for calibrating the position of the placement head according to claim 2, characterized in that, The positioning target is set on the positioning fixture, and the positioning fixture is fixed to the mounting head; The positioning fixture includes a positioning target and a base. The positioning target is a marked point set on the surface of the positioning target. The base can be adsorbed and fixed on the suction head seat of the mounting head.

8. A placement head position calibration system, characterized in that, include: The acquisition module is used to acquire the standard center axis position data of the rotation axis of the placement head, as well as the center axis position data of the rotation axis of the placement head after the parts have been replaced. The calculation module is used to calculate the deviation between the center axis position data and the standard center axis position data; An adjustment module is used to adjust the mounting position of the mounting head on its track when the deviation exceeds a preset allowable range, until the deviation meets the preset allowable range.

9. A position calibration device for a placement head, characterized in that, include: A positioning fixture is fixed to the placement head and rotates synchronously with the rotation axis of the placement head; the positioning fixture includes a positioning target. A vision system is used to acquire target point images of the positioning target. A drive controller is used to control the rotation of the rotation axis of the placement head and to control the movement of the placement head along the track in the direction of the rotation axis; A positioning adjustment mechanism is used to adjust the mounting position of the rotating shaft of the mounting head on the track; The position calibration system for the mounting head as described in claim 8, wherein the position calibration system is communicatively connected to the vision system, the drive controller, and the positioning adjustment mechanism.

10. The position calibration device according to claim 9, characterized in that, The vision system includes a telecentric lens, a camera, and a light source; the drive controller is also used to control the vision system and the placement head to move synchronously in the direction of rotation axis via a stepper motor slide on which the vision system is mounted.

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