CN103945653A - Automatic correction method of multi-degree-of-freedom platform for flexible printed circuit printing - Google Patents

Abstract

The invention discloses an automatic correction method for a multi-freedom platform printed on a flexible circuit board. The present invention specifically includes the following steps: Step 1. Building a multi-degree-of-freedom platform for printing on flexible circuit boards; Step 2. In the calibration stage, specifying the location and identifying the center coordinates of the two symbol circles on the flexible circuit board to be calibrated, and calculating the connecting line between the centers of the circles The inclination angle, set the obtained center coordinates and inclination angle as the reference position; Step 3. Calibration stage, specifically including establishing a calibration model and automatically correcting and detecting the flexible circuit board to be corrected; Step 4. Alignment stage, specifically referring to aligning the flexible circuit board to be corrected Flexible circuit board, reducing distance deviation. The invention overcomes the technical deficiencies in the existing printing process, makes up for the defect that it is difficult to accurately locate in the printing process, meets the high-precision printing requirements in the flexible circuit board printing process, and realizes the automation of the flexible circuit board printing process.

Description

Automatic correction method of multi-degree-of-freedom platform for flexible circuit board printing

technical field

The invention relates to an automatic correction and alignment method for materials to be printed, in particular to an automatic correction method for a multi-degree-of-freedom platform printed on a flexible circuit board. the

Background technique

Flexible printed circuit (Flexible Printed Circuit) is a printed circuit made of flexible insulating substrates, which has many advantages that rigid printed circuit boards do not have. It is easy to bend, wind and fold, and can be arranged arbitrarily according to the requirements of space layout, and can be moved and stretched arbitrarily in three-dimensional space, so as to achieve the integration of component assembly and wire connection. the

Due to the characteristics of flexible circuit boards that are easy to deform, they are prone to bending, winding or defects due to factors such as static electricity and air pressure during processing, which makes flexible circuit boards difficult to process. Many processes rely on manual solutions, and the automation level of the industry is biased. Low. the

Printing is an important link in the processing of flexible circuit boards, and it is often necessary to print multiple layers of coatings of different materials. During the printing process, the relative positional relationship of each layer of material is extremely strict, and generally a slight deviation will easily lead to the scrapping of the entire flexible board. Therefore, the precise positioning of the printing platform is extremely important. The current mainstream fixing method is to erect two positioning columns on the platform, and directly set the positioning holes on the flexible board on the positioning columns, so as to realize the positioning of the flexible circuit board. This method is simple and efficient, but it also has some serious shortcomings: the probability of printing misalignment is high, the efficiency and quality are difficult to guarantee, and it is difficult to meet the needs of high-precision printing. the

Contents of the invention

The purpose of the present invention is to overcome the technical deficiencies in the existing flexible circuit board printing process, make up for the defects that are difficult to accurately locate during the printing process, and provide an automatic correction method for the multi-degree-of-freedom platform of flexible circuit board printing, which meets the needs of flexible circuit board printing. The high-precision printing requirements in the process realize the automation of the flexible circuit board printing process. the

The technical solution adopted by the present invention to solve its technical problems comprises the steps:

Step 1. Build a multi-degree-of-freedom platform for flexible circuit board printing;

Step 2. In the calibration stage, specify the location to identify the center coordinates of the two mark circles on the flexible circuit board to be calibrated, calculate the inclination angle of the line connecting the circle centers, and set the obtained circle center coordinates and inclination angle as the reference position;

Step 3. Calibration phase, specifically including establishment of a calibration model and automatic calibration and detection of the flexible circuit board to be corrected;

Step 4. Alignment stage, specifically refers to aligning the flexible circuit board to be corrected to reduce the distance deviation. the

The multi-degree-of-freedom platform for flexible circuit board printing established in step 1 is mainly used to control the printing alignment of the flexible circuit board. By identifying the mark circle on the flexible circuit board and correcting the model, the correction pulse of each motor is calculated. By controlling The movement of the motor realizes the alignment and printing of the material to be printed. the

The multi-degree-of-freedom platform for flexible circuit board printing built in step 1 includes a base, a rotary printing platform, a motion actuator, and 2 industrial cameras;

There are two camera observation holes on the rotary printing platform, namely observation hole 1# and observation hole 2#; the motion actuator includes motor X, motor Y1 and motor Y2, the motion actuator is fixed on the base, and at the same time it is connected with the rotary printing platform Connected, used to support the rotary printing platform and control the platform to rotate and translate; the motor X is used to control the movement of the X-axis direction; the synchronous movement of the motors Y1 and Y2 is used to control the movement of the Y-axis direction; if a single motor moves, This will cause the rotation and translation of the rotary printing platform; 2 industrial cameras are fixed on the base, and the images of the two mark circles on the flexible circuit board are taken through the observation hole 1# and the observation hole 2# on the rotary printing platform. the

The calibration stage described in step 2 is as follows:

Fix the flexible circuit board to be calibrated on the rotary printing platform, so that the two mark circles on the flexible circuit board correspond to the observation hole 1# and the observation hole 2# respectively; two industrial cameras pass through the observation hole 1# and the observation hole 2# Shoot the mark circle on the flexible circuit board, thereby positioning and calculating the center coordinates of the two mark circles on the flexible circuit board, and calculate the inclination angle formed by the connection line of the two mark circles on the flexible circuit board and the rotating printing platform according to the center coordinates, and The coordinates of the center of the circle and the inclination are set as the reference position, that is, the coordinates of the center of the circle are the coordinates of the reference center of the circle, and the inclination is the reference inclination;

The calculation process of the center position and inclination angle of the line connecting the two marking circles of the flexible circuit board, that is, the reference circle center coordinates and the reference inclination angle is as follows:

2-1. The coordinates (x, y) of the center of the circle relative to the field of view reference point (m, n) obtained by the industrial camera 2# through the observation hole 2# are:

x＝ccosα-dsinα

y＝dcosα+csinα

Among them, α is the angle formed by the image space 1# obtained by industrial camera 1# through observation hole 1# and the image space 2# obtained by camera 2# through observation hole 2#, (c,d) is the angle formed by industrial camera 2# through observation hole 2# Observation hole 2# obtains the coordinates of the center of the circle 2# in the image space 2#;

2-2. Calculate the inclination angle θ formed by the line connecting the centers of the two logo circles and the x-axis of the rotary printing platform as:

$\begin{array}{c}\mathrm{<span\; class="notranslate">\; the\; tan</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; b</span>}}{\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; a</span>}}\\ <span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; b</span>}}{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; a</span>}}\end{array}<span\; class="notranslate">\; ;</span>$

Among them, (a, b) are the coordinates of the center of the marker circle 1# in the image space 1# captured by the industrial camera 1# through the observation hole 1#. the

The correction stage described in step 3 is as follows:

Fix the flexible circuit board to be calibrated on the rotary printing platform, so that the two mark circles on the flexible circuit board correspond to the observation hole 1# and the observation hole 2# respectively; then compare the current positions of the two mark circles in the calibration stage with the reference position;

If the current position of the two marker circles in the calibration phase and the calibration phase are the same as the target reference position, no calibration is required;

If the deviation between the current position of the two marker circles and the reference position in the calibration phase and the calibration phase is less than or equal to the allowable error, go to step 4;

If the deviation between the current position of the two marker circles and the reference position in the calibration phase and the calibration phase is greater than the allowable error, the calibration is performed;

The correction process is completed by the correction model, and the correction model is established as follows:

3-1. Establish calibration target

The calibration goal is to realize that the two reference points on the flexible circuit board basically coincide with the reference position, and the deviation is controlled within the allowable error range;

3-2. Select the coordinate system

The coordinate systems involved in the correction calculation process include, for example, the platform coordinate system, camera coordinate system, and motor coordinate system, with the platform coordinate system as the reference coordinate system;

3-3. Calculate the correction pulse

The pulse correction process consists of the following three sub-steps:

3-3-1. Calculate the first translation pulse

Calculate the pulse required for the center of the mark circle 2# of the flexible circuit board to be corrected in the image space 2# obtained from the observation point 2# to translate from the current position to the position of the reference circle center;

P1 _x ＝(Δx YMoterK _y −YMoterK _x Δy)/(XMoterK _x YMoterK _y −YMoterK _x XMoterK _y ) (1)

P1 _y = (XMoterK _x Δy-Δx XMoterK _y )/(XMoterK _x YMoterK _y -YMoterK _x XMoterK _y ) (2)

Among them, P1 _x is the pulse required by motor X; P1 _y is the pulse required by motor Y1 and Y2; Δx, Δy are the camera coordinate system, the flexible circuit board to be corrected obtained from observation point 2# in the image space 2# The pixel difference between the current position of the center of the mark circle 2# and the position of the reference center in the image space; (XMoterK _x , XMoterK _y ) is the ratio of the pulse of the motor X to the pixel; (YMoterK _x , YMoterK _y ) is the motor Y1 or Y2 The pulse-to-pixel ratio of

3-3-2. Calculate the rotation pulse

View and adjust the current inclination through the observation hole 1# and observation hole 2#, so that the line connecting the center of the mark circle on the flexible circuit board to be calibrated is parallel to the line connecting the center of the mark circle on the flexible circuit board to be calibrated; The inclination angle between the marking circle connection line on the circuit board and the rotating printing platform;

When the single Y-axis motor Y1 or Y2 moves, causing the target inclination angle to deviate, the reference position of the flexible circuit board to be corrected observed through the observation hole 1# and observation hole 2# will be offset and rotated, so that the current inclination angle is different from the reference position The inclination is basically the same;

The pulse calculation is measured by the difference between the coordinates of the current mark circle center of the observation hole 1# and the current mark circle center of the observation hole 2# and the coordinates of the reference circle center; at this time, the rotation pulse of the motor Y1 is as follows:

P2 _y1 = (w/d)·ΔPluse _1-2 (3)

Among them, w is the width of the supporting point of the rotating platform, d is the distance from the center of the marking circle, ΔPluse _1-2 is the image space of the marking circle 1# and the observation hole 2# in the image space acquired by the observation hole 1# The difference between the Y-axis motor pulse distance of the mark circle 2# in 2#, the pulse distance is the motor pulse required for the current target point to move to the reference point, that is, the calculation of the pulse in 3-3-1;

3-3-3. Calculate the second translation pulse

Compensate the coordinate deviation of the center of the marked circle observed from observation point 2# caused by the rotation of step 3-3-2, and translate again so that the position of the center of the marked circle observed by observation point 1# and observation point 2# is consistent with the position of the reference circle center;

Calculate the angle of rotation γ(R _Y1 ):

γ(R _Y1 )＝-sin ^-1 (R _Y1 /(MoterYK·w)) (4)

Among them, R _Y1 is the pulse distance of motor Y1, MoterYK is the K value of motor Y1 and Y2 in the Y direction, the unit is: pulse/mm;

Calculate the distance offset:

During the correction process, the rotating platform fulcrums B and B' are kept on the X-axis line, and the rotating platform fulcrums C and C' are also kept on the same straight line in the Y direction; the platform fulcrums B and C are symmetrical platform fulcrums ;

Described B is a fulcrum before the rotation of the rotary platform, B' is a fulcrum after the rotation of the rotary platform; C is a fulcrum before the rotation of the rotary platform, and C' is a fulcrum after the rotation of the rotary platform;

Based on the above constraints and the rigid motion law of the platform, the movement of the sign circle is decomposed into rotation and translation; the specific rotation is the rotation γ around the fulcrum C of the platform. At this time, the coordinates of the center of the sign circle 2# in the image space 2# obtained by the observation hole 2# The deviation is:

in, The polar coordinates of the reference point are observed for the observation point 2#; the specific translation is the translation along the X axis τ;

τ＝w·cos(γ)+h·sin(γ)-w (7)

Therefore, the center coordinate deviation of the mark circle 2# in the image space 2# acquired by the observation point 2# is ΔPos as follows: ΔPos=(ΔPos _x +τ, ΔPos _y );

Then the pulse deviation f(γ) caused by translation is:

f(γ)＝ΔP＝ΔPos·MoterK (8)

Among them, ΔPos=(ΔPos _x , ΔPos _y ), and MoterK=(MoterK _x , MoterK _y ), indicating the joint K value of motor X, motor Y1 and Y2;

Since the motor Y1 has a certain pulse deviation (Org_P _y1 ) from the ideal position at the beginning of the calibration process, at this time, the translation compensation pulse P3 is set as:

P3=f(γ(Org_P _y1 +R _Y1 ))-f(γ(Org_P _y1 )) (9)

Finally, from equations (1), (2), (3) and (9):

Motor X pulse is: P1 _x +P3 _x

Motor Y1 pulse is: P1 _y +P2 _y1 +P3 _y

Motor Y2 pulse is: P1 _y +P3 _y

3-4. Control the movement of the motor to realize the alignment and printing of the materials to be printed

According to the correction pulses of the three motors calculated in the above correction model, the movement of motor X, motor Y1 and motor Y2 is controlled, and the flexible circuit board with correction is automatically corrected and aligned;

3-5. Detection and correction results

If the deviation between the position of the two mark circles of the calibrated flexible circuit board and the reference position is less than the allowable error, go to step 4.;

If the deviation between the corrected positions of the two mark circles of the flexible circuit board and the reference position is greater than the allowable error, repeat steps 3-1 to 3-3. the

The allowable error is specifically related to the actual needs of the industry, and is generally 0.1mm. the

The ideal position means that the motor coordinate system is completely consistent with the platform coordinate system, and the X motor is consistent with the X axis direction. the

The alignment phase described in step 4 is as follows:

After the correction calculation and motor movement in step 3, when the sign circles observed by observation point 1# and observation point 2# are close to the reference position, if there is a certain distance deviation, make appropriate adjustments through the alignment method, as follows:

Left alignment: the reference position of the marker circle 1# in the image space 1# acquired by the observation hole 1# is used as the reference, align the flexible circuit board to be corrected, and make the reference position deviation of the marker circle in the image space 1# acquired by the observation hole 1# reduce;

Center alignment: adjust the rotating printing platform so that the deviation between the material to be aligned and the mark circle in the image space obtained by observation hole 1# and observation hole 2# is basically average; right alignment: the mark circle 1 in the image space 1# obtained by observation hole 2# The reference position of # is used as the benchmark, and the flexible circuit board to be corrected is aligned, so that the deviation of the reference position of the marker circle in the image space 2# acquired by the observation hole 2# is reduced. the

The beneficial effects of the present invention are as follows:

The invention overcomes the technical deficiencies in the existing printing process, makes up for the defect that it is difficult to accurately locate in the printing process, meets the high-precision printing requirements in the flexible circuit board printing process, and realizes the automation of the flexible circuit board printing process. the

Description of drawings

Figure 1 is a schematic diagram of the multi-degree-of-freedom platform for flexible circuit board printing;

Fig. 2 is the overall algorithm flow chart of the automatic calibration process of the flexible circuit board console;

Figure 3(a) is a schematic diagram of the spatial position of the camera image;

Figure 3(b) is a schematic diagram of the spatial position of the camera image;

Figure 4 is a schematic diagram of the platform coordinate system;

Fig. 5 is the calibration analysis schematic diagram of target point and reference point;

Fig. 6 is a schematic diagram of the motion of the rotary platform generated by the motion of the motor Y1. the

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments, so as to further explain the technical features and advantages of the present invention. the

An automatic correction method for a multi-degree-of-freedom platform printed on a flexible circuit board, specifically including the following steps:

Step 1. Build a multi-degree-of-freedom platform for flexible circuit board printing;

Step 2. In the calibration stage, specify the location to identify the center coordinates of the two mark circles on the flexible circuit board to be calibrated, calculate the inclination angle of the line connecting the circle centers, and set the obtained circle center coordinates and inclination angle as the reference position;

Step 3. Calibration phase, specifically including establishment of a calibration model and automatic calibration and detection of the flexible circuit board to be corrected;

Step 4. The alignment stage, specifically refers to the alignment of the flexible circuit board to be corrected to reduce the distance deviation;

The multi-degree-of-freedom platform for flexible circuit board printing established in step 1 is mainly used to control the printing alignment of the flexible circuit board. By identifying the mark circle on the flexible circuit board and correcting the model, the correction pulse of each motor is calculated. By controlling The movement of the motor realizes the alignment and printing of the material to be printed. the

As shown in Figure 1, the multi-degree-of-freedom platform for flexible circuit board printing built in step 1 includes a base, a rotary printing platform, a motion actuator, and 2 industrial cameras;

There are two camera observation holes on the rotary printing platform, namely observation hole 1# and observation hole 2#. The rotary printing platform has 3 degrees of freedom, which are used to support translation and rotation in the directions of X and Y axes. the

The motion actuator includes motor X, motor Y1, and motor Y2. The three motors are stepping motors or servo motors. The motion actuator is fixed on the base and connected to the rotary printing platform at the same time to support the rotary printing platform and control the rotation of the platform. and panning motion. Among them, the motor X is used to control the movement of the X-axis direction; the synchronous movement of the motors Y1 and Y2 is used to control the movement of the Y-axis direction; if a single motor moves, it will cause the rotation and translation of the rotary printing platform (including translation in the X and Y directions ). the

Two industrial cameras are fixed on the base, and the images of the two mark circles on the flexible circuit board are taken through the observation hole 1# and the observation hole 2# on the rotating printing platform. the

As shown in Figure 2, the calibration stage described in step 2 is as follows:

Fix the flexible circuit board to be calibrated on the rotary printing platform, so that the two mark circles on the flexible circuit board correspond to the observation hole 1# and the observation hole 2# respectively; two industrial cameras pass through the observation hole 1# and the observation hole 2# Shoot the mark circle on the flexible circuit board, thereby positioning and calculating the center coordinates of the two mark circles on the flexible circuit board, and calculate the inclination angle formed by the connection line of the two mark circles on the flexible circuit board and the rotating printing platform according to the center coordinates, and The coordinates of the center of the circle and the inclination are set as the reference position, that is, the coordinates of the center of the circle are the coordinates of the reference center of the circle, and the inclination is the reference inclination;

As shown in Figure 3, the calculation process of the center position and inclination angle of the line connecting the two marking circles of the flexible circuit board, that is, the reference circle center coordinates and the reference inclination angle is as follows:

2-1. The coordinates (x, y) of the center of the circle relative to the field of view reference point (m, n) obtained by the industrial camera 2# through the observation hole 2# are:

x＝ccosα-dsinα

y＝dcosα+csinα

Among them, α is the angle formed by the image space 1# obtained by industrial camera 1# through observation hole 1# and the image space 2# obtained by camera 2# through observation hole 2#, (c,d) is the angle formed by industrial camera 2# through observation hole 2# Observation hole 2# obtains the coordinates of the center of the circle 2# in the image space 2#;

2-2. Calculate the inclination angle θ formed by the line connecting the centers of the two logo circles and the x-axis of the rotary printing platform as:

$\begin{array}{c}\mathrm{<span\; class="notranslate">\; the\; tan</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; b</span>}}{\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; a</span>}}\\ <span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; b</span>}}{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; a</span>}}\end{array}<span\; class="notranslate">\; ;</span>$

Among them, (a, b) is the center coordinate of the sign circle 1# in the image space 1# obtained by the industrial camera 1# through the observation hole 1#;

The correction stage described in step 3 is as follows:

Fix the flexible circuit board to be calibrated on the rotary printing platform, so that the two mark circles on the flexible circuit board correspond to the observation hole 1# and the observation hole 2# respectively; then compare the current positions of the two mark circles in the calibration stage with the reference position;

If the current position of the two marker circles in the calibration phase and the calibration phase are the same as the target reference position, no calibration is required;

If the deviation between the current position of the two marker circles and the reference position in the calibration phase and the calibration phase is less than or equal to the allowable error, go to step 4;

If the deviation between the current position of the two marker circles and the reference position in the calibration phase and the calibration phase is greater than the allowable error, the calibration is performed;

The allowable error is specifically related to the actual needs of the industry, and is generally 0.1 mm. the

The correction process is completed by the correction model, and the correction model is established as follows:

3-1. Establish calibration target

The calibration goal is to realize that the positions of the two reference points on the flexible circuit board basically coincide with the reference position, and the deviation is controlled within the allowable error range. the

3-2. Select the coordinate system

The coordinate systems involved in the correction calculation process include the platform coordinate system, camera coordinate system (2 cameras), motor coordinate system (3 motors), as shown in Figure 4, the platform coordinate system is used as the reference coordinate system;

In the process of calibration calculation, multiple coordinate systems are involved, such as platform coordinate system, camera coordinate system (2 cameras), motor coordinate system (3 motors), the selection of coordinate system is related to the complexity of the calibration model, and each coordinate system In addition to positional deviations, the units and scales are different, and to complicate matters there may be angular deviations, even in the Z direction. For example, the motor coordinate system is not completely consistent with the X-axis or Y-axis of the platform, and there is a certain inclination angle in the camera installation, resulting in some deviations in the Z direction, which increases the complexity of the problem. In order to simplify the model analysis, the deviation of each coordinate system in the Z direction caused by the mechanical installation is ignored, and the platform coordinate system is used as the reference coordinate system. the

3-3. Calculate the correction pulse

The pulse correction process consists of the following three sub-steps:

3-3-1. Calculate the first translation pulse

(a). Calculate the pulse required to translate the center of the mark circle 2# from the current position to the reference center position of the flexible circuit board to be corrected in the image space 2# obtained from the observation point 2#;

P1 _x ＝(Δx YMoterK _y −YMoterK _x Δy)/(XMoterK _x YMoterK _y −YMoterK _x XMoterK _y ) (1)

P1 _y = (XMoterK _x Δy-Δx XMoterK _y )/(XMoterK _x YMoterK _y -YMoterK _x XMoterK _y ) (2)

Among them, P1 _x is the pulse required by motor X; P1 _y is the pulse required by motor Y1 and Y2; Δx, Δy are the camera coordinate system, the flexible circuit board to be corrected obtained from observation point 2# in the image space 2# The pixel difference between the current position of the center of the mark circle 2# and the position of the reference center in the image space; (XMoterK _x , XMoterK _y ) is the ratio of the pulse of the motor X to the pixel; (YMoterK _x , YMoterK _y ) is the motor Y1 or Y2 The pulse-to-pixel ratio of

3-3-2. Calculate the rotation pulse

View and adjust the current inclination through the observation hole 1# and observation hole 2#, so that the line connecting the center of the mark circle on the flexible circuit board to be calibrated is parallel to the line connecting the center of the mark circle on the flexible circuit board to be calibrated; The inclination angle between the marking circle connection line on the circuit board and the rotating printing platform. the

As shown in Figure 5, due to the movement of a single Y-axis motor Y1 or Y2, during the rotation phase, that is, when the target inclination angle is offset, the reference of the flexible circuit board to be corrected observed through the observation hole 1# and observation hole 2# The position is shifted and rotated so that the current inclination is basically the same as the reference inclination. the

At this time, because the deflection angle of the flexible circuit board to be corrected is small, the pulse calculation is measured by the difference between the coordinates of the current mark circle center of the observation hole 1# and the current mark circle center of the observation hole 2# and the coordinates of the reference circle center; At this time, the rotation pulse (motor Y1 pulse) is as follows:

P2 _y1 = (w/d)·ΔPluse _1-2 (3)

Among them, w is the width of the support point of the rotating platform, and d is the distance between the centers of the sign circles. Considering that the centers of the two sign circles are far away, the distance between the center points of the two cameras is generally used as the standard. ΔPluse _1-2 is the difference between the Y-axis motor pulse distance of the symbol circle 1 in the image space 1 obtained by the observation hole 1# and the Y-axis motor pulse distance of the symbol circle 2# in the image space 2# obtained by the observation hole 2#, and the pulse The distance is the motor pulse required for the current target point to move to the reference point, which is the calculation of the pulse in 3-3-1.

3-3-3. Calculate the second translation pulse

Compensate the coordinate deviation of the center of the marked circle observed from observation point 2# caused by the rotation of step 3-3-2, and translate again so that the position of the center of the marked circle observed by observation point 1# and observation point 2# is consistent with the position of the reference circle center;

As shown in Figure 6, when the motor Y1 moves, the platform will not only rotate, but also translate appropriately as a whole; at this time, the position of the center of the marked circle observed by the coincident observation point 2# in step 1 will deviate again, and it must be Compensate appropriately. the

Calculate the angle of rotation θ( _RY1 ):

γ(R _Y1 )＝-sin ^-1 (R _Y1 /(MoterYK·w)) (4)

Among them, R _Y1 is the pulse distance of motor Y1, MoterYK is the K value of motor Y1 and Y2 in the Y direction, the unit is: pulse/mm;

Calculate the distance offset:

During the calibration process, the rotating platform fulcrums B and B' are kept on the same straight line (X axis), and the rotating platform fulcrums C and C' are also kept on the same straight line in the Y direction (Y axis);

Described B is a fulcrum before the rotation of the rotary platform, B' is a fulcrum after the rotation of the rotary platform; C is a fulcrum before the rotation of the rotary platform, and C' is a fulcrum after the rotation of the rotary platform;

Based on the above constraints and the law of rigid motion of the platform, the circular movement of the sign is decomposed into rotation and translation without affecting the accuracy of calculation, as shown in the shaded area in Figure 6. the

The specific rotation is to rotate γ around the fulcrum C. At this time, the center coordinate deviation of the mark circle 2# in the image space 2# acquired by the observation hole 2# is:

in, Observe the polar coordinates of the reference point for observation point 2#;

The specific translation is translation along the X axis τ

τ＝w·cos(γ)+h·sin(γ)-w (7)

Therefore, the center coordinate deviation of the mark circle 2# in the image space 2# acquired by the observation point 2# is ΔPos as follows: ΔPos=(ΔPos _x +τ, ΔPos _y );

Then the pulse deviation f(γ) caused by translation is:

f(γ)＝ΔP＝ΔPos·MoterK (8)

Among them, ΔPos=(ΔPos _x , ΔPos _y ), and MoterK=(MoterK _x , MoterK _y ), indicating the joint K value of motor X, motor Y1 and Y2 (unit: pulse/mm).

Since there is a certain pulse deviation (Org_P _y1 ) between the motor Y1 and the ideal position in the calibration platform at the beginning,

At this point, the translation compensation pulse P3 is set to:

P3=f(γ(Org_P _y1 +R _Y1 ))-f(γ(Org_P _y1 )) (9)

Finally, the pulses of the 3 motors are given by formulas 1, 2, 3, and 9, respectively. the

Motor X pulse is: P1 _x +P3 _x

Motor Y1 pulse is: P1 _y +P2 _y1 +P3 _y

Motor Y2 pulse is: P1 _y +P3 _y

The ideal position mentioned above considers that the motor coordinate system is completely consistent with the platform coordinate system, and the X motor is in the same direction as the X axis, such as the Y1 and y2 motors are in the same direction as the Y axis. the

3-4. Control the movement of the motor to realize the alignment and printing of the materials to be printed

According to the correction pulses of the three motors calculated in the above correction model, the movement of motor X, motor Y1 and motor Y2 is controlled, and the flexible circuit board with correction is automatically corrected and aligned. the

3-5. Detection and correction results

If the deviation between the position of the two mark circles of the calibrated flexible circuit board and the reference position is less than the allowable error, go to step 4.;

If the deviation between the position of the two mark circles of the calibrated flexible circuit board and the reference position is greater than the allowable error, then repeat steps 3-1 to 3-3;

The alignment phase described in step 4 is as follows:

After the correction calculation and motor movement in step 3, the sign circles observed by observation point 1# and observation point 2# are basically close to the reference position, sometimes there will be a certain distance deviation, mainly due to the irregularity of the flexible circuit board material itself and the difference in expansion and contraction , resulting in a change in the distance between the two sign circles. At this time, it is necessary to detect the abnormality in time and make appropriate adjustments through the alignment method, as follows:

Left alignment: The reference position of the marker circle 1# in the image space 1# acquired by the observation hole 1# is used as the reference, and the flexible circuit board to be corrected is aligned, as far as possible with the reference position of the marker circle in the image space 1 acquired by the observation hole 1# less deviation;

Center alignment: adjust the rotating printing platform so that the deviation between the material to be aligned and the mark circle in the image space obtained by observation hole 1# and observation hole 2# is basically average; right alignment: the reference of the mark circle in image space 2 obtained by observation hole 2# The position is used as the reference, and the flexible circuit board to be corrected is aligned, and the deviation from the reference position of the marker circle in the image space 2 acquired by the observation hole 2# is as small as possible. the

Claims (7)

1. The automatic correction method of the multi-degree-of-freedom platform of flexible circuit board printing is characterized in that comprising the following steps: Step 1. Build a multi-degree-of-freedom platform for flexible circuit board printing; Step 2. In the calibration stage, specify the location to identify the center coordinates of the two mark circles on the flexible circuit board to be calibrated, calculate the inclination angle of the line connecting the circle centers, and set the obtained circle center coordinates and inclination angle as the reference position; Step 3. Calibration stage, specifically including establishment of a calibration model and automatic calibration and detection of the flexible circuit board to be corrected; Step 4. The alignment stage, specifically refers to aligning the flexible circuit board to be corrected to reduce the distance deviation; The multi-degree-of-freedom platform for flexible circuit board printing established in step 1 is mainly used to control the printing alignment of the flexible circuit board. By identifying the mark circle on the flexible circuit board and correcting the model, the correction pulse of each motor is calculated. By controlling The movement of the motor realizes the alignment and printing of the material to be printed. 2. The automatic correction method of the multi-degree-of-freedom platform of flexible circuit board printing as claimed in claim 1, is characterized in that: The multi-degree-of-freedom platform for flexible circuit board printing built in step 1 includes a base, a rotary printing platform, a motion actuator, and 2 industrial cameras; There are two camera observation holes on the rotary printing platform, namely observation hole 1# and observation hole 2#; the motion actuator includes motor X, motor Y1 and motor Y2, the motion actuator is fixed on the base, and at the same time it is connected with the rotary printing platform Connected, used to support the rotary printing platform and control the platform to rotate and translate; the motor X is used to control the movement of the X-axis direction; the synchronous movement of the motors Y1 and Y2 is used to control the movement of the Y-axis direction; if a single motor moves, This will cause the rotation and translation of the rotary printing platform; 2 industrial cameras are fixed on the base, and the images of the two mark circles on the flexible circuit board are taken through the observation hole 1# and the observation hole 2# on the rotary printing platform. 3. The automatic correction method of the multi-degree-of-freedom platform of flexible circuit board printing as claimed in claim 1, is characterized in that: The calibration stage described in step 2 is as follows: Fix the flexible circuit board to be calibrated on the rotary printing platform, so that the two mark circles on the flexible circuit board correspond to the observation hole 1# and the observation hole 2# respectively; two industrial cameras pass through the observation hole 1# and the observation hole 2# Shoot the mark circle on the flexible circuit board, thereby positioning and calculating the center coordinates of the two mark circles on the flexible circuit board, and calculate the inclination angle formed by the connection line of the two mark circles on the flexible circuit board and the rotating printing platform according to the center coordinates, and The circle center coordinates and inclination angle are set as the reference position, that is, the circle center coordinates are the reference circle center coordinates, and the inclination angle is the reference inclination angle; The calculation process of the center position and inclination angle of the line connecting the two marking circles of the flexible circuit board, that is, the reference circle center coordinates and the reference inclination angle is as follows: 2-1. The coordinates (x, y) of the center of the circle relative to the field of view reference point (m, n) obtained by the industrial camera 2# through the observation hole 2# are: x = ccosα-dsinα y=dcosα+csinα Among them, α is the angle formed by the image space 1# obtained by industrial camera 1# through observation hole 1# and the image space 2# obtained by camera 2# through observation hole 2#, (c,d) is the angle formed by industrial camera 2# through observation hole 2# The coordinates of the center of the circle 2# in the image space 2# acquired by the observation hole 2#; 2-2. Calculate the inclination angle θ formed by the line connecting the centers of the two logo circles and the x-axis of the rotary printing platform as: $\begin{array}{c}\mathrm{<span\; class="notranslate">\; the\; tan</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; b</span>}}{\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; a</span>}}\\ <span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; b</span>}}{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; a</span>}}\end{array}<span\; class="notranslate">\; ;</span>$ Among them, (a, b) are the coordinates of the center of the marker circle 1# in the image space 1# captured by the industrial camera 1# through the observation hole 1#. 4. The automatic correction method of the multi-degree-of-freedom platform of flexible circuit board printing as claimed in claim 1, is characterized in that: The correction stage described in step 3 is as follows: Fix the flexible circuit board to be calibrated on the rotary printing platform, so that the two mark circles on the flexible circuit board correspond to the observation hole 1# and the observation hole 2# respectively; then compare the current positions of the two mark circles in the calibration stage with the reference position; If the current positions of the two marker circles in the calibration phase and the calibration phase are the same as the target reference position, no calibration is required; If the deviation between the current position of the two marker circles and the reference position in the calibration phase and the calibration phase is less than or equal to the allowable error, go to step 4; If the deviation between the current position of the two marker circles and the reference position in the calibration stage and the correction stage is greater than the allowable error, the correction is performed; The correction process is completed by a correction model, and the correction model is established as follows: 3-1. Establish calibration target The calibration goal is to realize that the two reference points on the flexible circuit board basically coincide with the reference position, and the deviation is controlled within the allowable error range; 3-2. Select the coordinate system The coordinate systems involved in the correction calculation process include, for example, the platform coordinate system, camera coordinate system, and motor coordinate system, with the platform coordinate system as the reference coordinate system; 3-3. Calculation of correction pulses The pulse correction process consists of the following three sub-steps: 3-3-1. Calculate the first translation pulse Calculate the pulse required for the center of the mark circle 2# of the flexible circuit board to be corrected in the image space 2# obtained from the observation point 2# to translate from the current position to the position of the reference center of the circle; P1 _x ＝(Δx YMoterK _y −YMoterK _x Δy)/(XMoterK _x YMoterK _y −YMoterK _x XMoterK _y ) (1) P1 _y = (XMoterK _x Δy-Δx XMoterK _y )/(XMoterK _x YMoterK _y -YMoterK _x XMoterK _y ) (2) Among them, P1 _x is the pulse required by motor X; P1 _y is the pulse required by motor Y1 and Y2; Δx, Δy are the camera coordinate system, the flexible circuit board to be corrected obtained from observation point 2# in the image space 2# The pixel difference between the current position of the center of the mark circle 2# and the position of the reference center in the image space; (XMoterK _x , XMoterK _y ) is the ratio of the pulse of the motor X to the pixel; (YMoterK _x , YMoterK _y ) is the motor Y1 or Y2 The pulse-to-pixel ratio of 3-3-2. Calculation of rotation pulse View and adjust the current inclination through the observation hole 1# and observation hole 2#, so that the line connecting the center of the mark circle on the flexible circuit board to be calibrated is parallel to the line connecting the center of the mark circle on the flexible circuit board to be calibrated; The inclination angle between the marking circle connection line on the circuit board and the rotating printing platform; When the single Y-axis motor Y1 or Y2 moves, causing the target inclination angle to deviate, the reference position of the flexible circuit board to be corrected observed through the observation hole 1# and observation hole 2# will be offset and rotated, so that the current inclination angle is different from the reference position The inclination is basically the same; The pulse calculation is measured by the difference between the coordinates of the current mark circle center of the observation hole 1# and the current mark circle center of the observation hole 2# and the coordinates of the reference circle center; at this time, the rotation pulse of the motor Y1 is as follows: P2 _y1 = (w/d)·ΔPluse _1-2 (3) Among them, w is the width of the supporting point of the rotating platform, d is the distance from the center of the marking circle, ΔPluse _1-2 is the image space of the marking circle 1# and the observation hole 2# in the image space acquired by the observation hole 1# The difference between the Y-axis motor pulse distance of the mark circle 2# in 2#, the pulse distance is the motor pulse required for the current target point to move to the reference point, that is, the calculation of the pulse in 3-3-1; 3-3-3. Calculate the second translation pulse Compensate the coordinate deviation of the center of the marked circle observed from observation point 2# caused by the rotation of step 3-3-2, and translate again so that the position of the center of the marked circle observed by observation point 1# and observation point 2# is consistent with the position of the reference circle center; Calculate the angle of rotation γ(R _Y1 ): γ(R _Y1 )＝-sin ^-1 (R _Y1 /(MoterYK·w)) (4) Among them, R _Y1 is the pulse distance of motor Y1, MoterYK is the K value of motor Y1 and Y2 in the Y direction, the unit is: pulse/mm; Calculate the distance offset: During the correction process, the rotating platform fulcrums B and B' are kept on the X-axis line, and the rotating platform fulcrums C and C' are also kept on the same straight line in the Y direction; the platform fulcrums B and C are symmetrical platform fulcrums ; Described B is a fulcrum before the rotary platform rotates, and B' is a fulcrum after the rotary platform rotates; C is a fulcrum before the rotary platform rotates, and C' is a fulcrum after the rotary platform rotates; Based on the above constraints and the rigid motion law of the platform, the movement of the sign circle is decomposed into rotation and translation; the specific rotation is the rotation γ around the fulcrum C of the platform. At this time, the coordinates of the center of the sign circle 2# in the image space 2# obtained by the observation hole 2# The deviation is: in, Observe the polar coordinates of the reference point for observation point 2#; The specific translation is to translate τ along the X axis τ＝w·cos(γ)+h·sin(γ)-w (7) Therefore, the center coordinate deviation of the mark circle 2# in the image space 2# acquired by the observation point 2# is ΔPos as follows: ΔPos=(ΔPos _x +τ, ΔPos _y ); Then the pulse deviation f(γ) caused by translation is: f(γ)＝ΔP＝ΔPos·MoterK (8) Among them, ΔPos=(ΔPos _x , ΔPos _y ), and MoterK=(MoterK _x , MoterK _y ), indicating the joint K value of motor X, motor Y1 and Y2; Since the motor Y1 has a certain pulse deviation (Org_P _y1 ) from the ideal position at the beginning of the calibration process, at this time, the translation compensation pulse P3 is set as: P3=f(γ(Org_P _y1 +R _Y1 ))-f(γ(Org_P _y1 )) (9) Finally, from equations (1), (2), (3) and (9): Motor X pulse is: P1 _x +P3 _x Motor Y1 pulse is: P1 _y +P2 _y1 +P3 _y Motor Y2 pulse is: P1 _y +P3 _y 3-4. Control the movement of the motor to realize the alignment and printing of the materials to be printed According to the correction pulses of the three motors calculated in the above correction model, the movement of motor X, motor Y1 and motor Y2 is controlled, and the flexible circuit board with correction is automatically corrected and aligned; 3-5. Detection and correction results If the deviation between the position of the two mark circles of the calibrated flexible circuit board and the reference position is less than the allowable error, proceed to step 4.; If the deviation between the corrected positions of the two mark circles of the flexible circuit board and the reference position is greater than the allowable error, repeat steps 3-1 to 3-3. 5. The automatic calibration method of the multi-degree-of-freedom platform printed on the flexible circuit board according to claim 4, characterized in that: the allowable error is specifically related to the actual needs of the industry, and is generally 0.1 mm. 6. The automatic calibration method of the multi-degree-of-freedom platform printed on flexible circuit boards according to claim 4, wherein the ideal position means that the motor coordinate system is completely consistent with the platform coordinate system, and the X motor is consistent with the X axis direction. 7. The automatic correction method of the multi-degree-of-freedom platform of flexible circuit board printing as claimed in claim 1, is characterized in that: The alignment phase described in step 4 is as follows: After the correction calculation and motor movement in step 3, when the sign circles observed by observation point 1# and observation point 2# are close to the reference position, if there is a certain distance deviation, make appropriate adjustments through the alignment method, as follows: Left alignment: the reference position of the marker circle 1# in the image space 1# acquired by the observation hole 1# is used as the reference, align the flexible circuit board to be corrected, and make the reference position deviation of the marker circle in the image space 1# acquired by the observation hole 1# decrease; Centering alignment: adjust the rotating printing platform so that the material to be aligned and the mark circle deviation in the image space obtained by observation hole 1# and observation hole 2# are basically average; Right alignment: The reference position of the marker circle 2# in the image space 2# acquired by the observation hole 2# is used as the reference, and the flexible circuit board to be corrected is aligned to make the reference position deviation of the marker circle in the image space 2# acquired by the observation hole 2# decrease.