Hi,
I'm making a PIC controlled CNC machine and I encountered a problem with simultaneous axis movement. Foe example I need to move the X axis 20mm, Y
41mm and Z 123mm at the same time. There are two modes:#1 is more important!
If anyone knowes of an algorithm, please share it Thanx
Google for Bresenham Algorithm.
In short you Compare the size of X & Y. Set up a loop counter the same size as the Larger. Step the Larger axis on each iteration of the loop. Step the smaller axis every 'n' iterations, where n is the Integer of the larger divided by the smaller. Hope that makes sense...
Take a look at
Good luck with it, J>
Assuming the point you are at is P1, and point you wanna get to is P2, find the largest coordinate difference: dX = Px2 - Px1 dY = Py2 - Py1 dZ = Pz2 - Pz1 dMax = MAX(MAX(dX,dY),dZ);
Calculate the step size for each direction stepX = dX / dMax; stepY = dY / dMax; stepZ = dZ / dMax;
initialize loop variables and perform motion: x = Px1;y = Py1;z = Pz1; for (i = 1;i < dMax; i++ ) { x = x + stepX; y = y + stepX; z = z + stepX; setPosition(x,y,z); }
Note that this can be done with fixed-point arithmetic, "stepN" variable size in floating point is always between 0.0 - 1.0 If you want to compute constant speed for motion properly, you need to use real vector magnitude instead of simply dMax, thats SQRT((Px2-Px1)^2 + (Py2-Py1)^2 + (Pz2-Pz1)^2 )
-kert
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