KE-750_MAINTE.pdf - 第110页
- For the BOC recognition per circuit From circuit No.1, in the same manner as for the BOC rec ognition per board, BOC mark recognition is performed per circuit. When recognition of all BOC marks on the circuit is comple…
3.12 BOC Mark Recognition
Operation timing
The figure below shows the operation timing of X-Y axes of the main unit and of
the recognition unit for BOC mark recognition.
To next action
X-Y axes
Recognition
unit
Camera change Image recognition Mark recognition
① When BOC recognition operation is started, the X-Y axes are started to
move to the BOC mark recognition position, and, at the same time, the
camera switch command to the BOC camera is sent to the recognition unit.
At this time, the BOC light turns on.
② When movement to the BOC mark recognition position is complete, the
BOC mark recognition command of the recognition unit is sent.
③ When the image recognition completion signal from the recognition unit is
received, the X-Y axes is started to move to the recognition position of the
next mark. After that, the mark recognition process is continued with the
recognition unit.
④ When the result of recognition from the recognition unit is received, the
camera switch command is sent again.
⑤ Steps ② to ④ are repeated until the last BOC mark. When the image of
the last BOC mark is obtained, the BOC light is turned off.
⑥ Waits the result of the image recognition of the last BOC mark from the
recognition unit, and performs the next action.
Recognition sequence
The sequence of BOC mark recognition is different between the BOC mark
recognition per board and the BOC mark recognition per circuit, and they are
performed as follows:
- For the BOC recognition per board
BOC mark recognition is performed from BOC mark position No.1, to No.2, to
No.3 which are shown as the board data.
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- For the BOC recognition per circuit
From circuit No.1, in the same manner as for the BOC recognition per board,
BOC mark recognition is performed per circuit. When recognition of all BOC
marks on the circuit is complete, BOC recognition process of the next circuit is
performed in ascending order of the circuit numbers.
The circuit numbers for non-matrix split boards, the order of the number is the
one for the circuit location input from the board data input.
The circuit numbers for matrix split boards, it is to be counted in an increasing
order of the X axis at the side of the circuit close to the machine origin of the X
axis. This is repeated in increasing order of the Y axis from the machine origin
side of the Y axis. For 4 by 4 matrix split boards, the circuit numbers are as
shown below.
Fiducial mark correction algorithm
In case of 3-point BOC mark
When points M1, M2, and M3 shown as (○) in the figure above are the BOC
mark coordinates in the board data, and when the actual coordinates obtained
by the recognition of each point are M1', M2', and M3' shown as (●), obtain
point P' (■) which is the actual mount coordinate with respect to point P (□)
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which is the mount coordinate of the mount data.
In this case, if it is assumed that the board is moved and deformed evenly,
obtain the coordinate of the rectangle coordinate which has origin (○)of point P'
on the angular coordinate made with M1', M2', and M3' with response to M1,
M2, and M3 which are equivalent to the coordinate of point P on the angular
coordinate which has two coordinate axes out of the straight lines which pass
two points out of three points, M1, M2, and M3.
In this case, a point of intersection of the two straight lines; one is drawn from P
in parallel with the angular coordinate axis and the other drawn from M1 to M2
is defined as P12, and another point of intersection of the two straight lines: one
is also drawn from P in parallel with the angular coordinate axis and the other
drawn from M1 to M3 is defined as P13. In the same manner, for P', a point of
intersection made by the straight line from M1' to M2' is defined as P12' and
made by the straight line from M1' to M3' is defined as P13'. Then, the
equations below can be obtained.
(M1→P) = (M1→P13) + (M1→P12) ①
(M1’→P’) = (M1’→P13’) + (M1’→P12’) ②
According to the definition of P', the following equations can be obtained.
|M1→P12|
|M1→M2|
|M1'→P12'|
|M1'→M2'|
=
|M1→P13|
|M1→M3|
|M1'→P13'|
|M1'→M3'|
=
Equations q and w can be as shown below when the result of equation e is A,
and that of equation r is B.
(M1→P) = B (M1→M13) + A (M1→M2) ⑤
(M1’→P’) = B (M1’→M3’) + A (M1’→M2’) ⑥
In the equations ⑤ and ⑥ on the previous page, vector coordinates M1, M2,
M3, P, M1', M2', M3', and P' on the rectangle coordinate whose origin is (
○) are
defined (x1, y1), (x2, y2), (x3, y3), (xp, yp), (x1', y1'), (x2', y2'), (x3', y3'), and (X,
Y), respectively. Then, the following equations can be obtained.
(xp, yp) - (x1, y1) = B ((x3, y3) - (x1, y1)) + A ((x2, y2) - (x1, y1))
(X, Y) - (x1’, Y1’) = B ((x3’, y3’) - (x1’, y1’)) + A ((x2’, y2’) - (x1, y1’))
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