Hi,
I am new to working with robots and I have this task of calibrating the robot. In order to initially identify the errors in the robot without feeding in the correct Transformation matrix, I move the robot from home position (perpendicular in A2, A3 and A4 axes)with null frame configuration(calibrate-> Tool-> Numeric Input) about the different axes (x,y and z) and have a CMM (co-ordinate measuring machine) to measure the errors about the different axes(translation and rotation).
I wrote a cnc code to move the robot in the different axes
e.g. G01 G90 X1500 Y-50 Z1700 A0 B0 C0 F4000 by changing the values in X,Y and z and in A,B and C
and when i ran the program for rotation, the robot rotates about two axes(Z,Y) but in the third axes(X) the rotation from one of the first two axes is repeated. When I manually rotate the robot in them using the pendant it rotates about all the different axes(X,Y and Z).
What didn't work:
- I thought that the robot might be at a singularity point and so moved it to a different home position and gave a point
e.g. G01 G90 X1500 Y-50 Z1500 A0 B0 C0 F4000
(rotation about z axis)
G01 G90 X1500 Y-50 Z1500 A30 B0 C0 F4000
(rotation about y axis)
G01 G90 X1500 Y-50 Z1500 A0 B30 C0 F4000
(rotation about x axis)
G01 G90 X1500 Y-50 Z1500 A0 B0 C30 F4000
In the last command the robot again rotates about the z axis (-ve direction)
. The results were disappointingly the same.
What worked:
- I have the frame of the robot in the last axes and so applied a transformation matrix from the last axes to the TCP in the tool option in calibrate menu. This time when i moved the robot using the cnc code the robot rotated about all the axes.
What I want to know:
- When I asked my boss if my approach with applying the transformation matrix was right, he told me that I have to calibrate without the transformation matrix. I am at a fix as to why the robot behaves so when I operate it in null frame configuration
P.S : Null frame configuration : X-0 Y-0 Z-0 and A-0, B-0 and C-0.