X,y,z new coordinate calculation for joint rotations in CoppeliaSimEdu

AI Thread Summary
A user is working on a 3D manipulator joint in CoppeliaSimEdu and is facing issues with the calculation of x and y coordinates, while the z coordinate appears correct. They provided a transformation matrix for the joint rotations but suspect an error in their calculations, particularly regarding the sine function in the matrix. Another participant suggests that the matrix is mostly correct but points out a potential mistake in the sine term and advises checking the dummy object's expected position. The discussion concludes with a formula for calculating x and y coordinates based on the lengths of the manipulator's segments and the angles of rotation. The user is encouraged to explore examples within CoppeliaSimEdu to better understand the program's functionality.
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I have problems with kinematic- > Rot(z,a1)Rot(z,a2)Trans(0,0,d) a1 and a2 angles d projection. My function was x = (d3+const)*math.cos(a1)*math.sin(a2) y = (d3*const)*math.const(a1)*math.sin(a2) but it not working.
I have created a 3D manipulator joint in CoppeliaSimEdu, I have the following joint rotation along the z axis, a second rotation joint raised in height and shifted along the x axis and further along the x axis is a directions joint. Or Rot(z,a1)Rot(z,a2)Trans(0,0,d) a1 and a2 angles d projection. But I have added a Dummy object to CoppeliaSim with which I set the x,y,z coordinates according to the kinematics calculations. But as far as I understand, I have a problem with the calculation of x and y coordinates, because the z coordinate is as it should be.

By connecting all the joints I got the matrix: [[cos(a1+a2), -sin(a1+a2),0,0],[sin(a2-a1),cos(a1+a2),0,0],[0,0,1,d ],[0,0,0,1]]

thus thinking that x = cos(a1+a2) + sin(a2-a1) y = -sin(a1+a2)+cos(a1+a2) z = d but the Dummy object doesn't move as it should, so I believe my x,y coordinates are wrong. How could I fix it?
 
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I am not familiar with CoppeliaSimEdu, but for some interpretations of your initial description your 4x4 matrix seems correct except for ##\sin(a2-a1)## which should be ##\sin(a1+a2)##. Note that two sequential rotations around any axis is equivalent to a single rotation about the exact same axis with the sum of the two angles.

I am not sure what you are saying next. Is (1, 1, 1) the position of your dummy object? And you expect it to shift around when you change your two angles and the offset? If so, it sounds like its more an issue with use of the program you use, so perhaps you can find an example that works and then try transform it to be applicable to your problem?
 
Thanks. Found answer.
x = l1*math.cos(teta1)+l2*math.cos(teta1 + teta2)
y = l1*math.sin(teta1)+l2*math.sin(teta1+ teta2)

where l1 and l2 are constant
 
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