Q: How do I calculate δθ for the rotation of the alignment platform (taking fitting as an example)?
From the formula δθ=δ6-δ5, we can know
A: If the product is relatively small, two cameras can be used to locate the reference point and the object respectively (generally as follows):
The following diagram illustrates this:
Vision can use template matching algorithms to calculate the coordinates (X, Y, θ) of a reference point; similarly, it can also calculate the coordinates of an object.
If the product is relatively large, you can calculate its center position and angle by using diagonal cameras. You can also use 4 or 8 cameras to determine the position of two products.
The following is a simple model for baseline localization using 8 cameras (4 for reference and 4 for the object).
The relationship between the image coordinates of the visual algorithm and the coordinates of the motor mechanism requires collaboration between software engineers and electrical engineers.
Suppose that the position of the object in the X0Y coordinate system obtained by image processing localization is (X5, Y5, δ5).
The position of the reference obtained by image processing positioning method in the XY coordinate system is (X6, Y6, δ6).
The resulting rotation data is:
δθ=δ6-δ5
X = X6 - X5
Y = Y6 - Y5
Assume the initial position (usually set as the origin, which needs to be returned to after each alignment) is horizontal. In this case, assume θ0 = 0.
According to the UVW calculation formula:
δX1=R*COS（δθ+θX1+θ0）-R*COS（+θX1+θ0）
δX2=R*COS（δθ+θX2+θ0）-R*COS（+θX2+θ0）
δY1=R*Sin（δθ+θY1+θ0）-R*Sin（+θY1+θ0）
Where θ0=0
δθ=δ6-δ5
θX1θX2θY1R (which is given at the factory) is known.
δX1δX2δY1 can then be calculated (where the unit is mm).
Then, add (or subtract) the corresponding values of X and Y to obtain the actual distance (mm) that the platform needs to travel:
δX1=δX1+X
δX² = δX² + X
δY1=δY1+Y
Then we can calculate the number of pulses needed to drive the X1 axis to move:
X1(pluse)=δX1*Mp.............(1)
(MP is the pulse equivalent, which is determined by the lead screw pitch and the encoder together.)
Similarly, the number of pulses for the X2 axis movement can be obtained as follows:
X2(pluse)=δX2*Mp.............(2)
The number of pulses for Y1 axis movement is:
Y1(pluse)=δY1*Mp.............(3)
The above is the calculation method and diagram of the alignment platform. YARAK alignment platform has extensive industry application experience and can provide you with professional answers to alignment platform questions. Welcome to call for consultation.
