I'm having some issues with a planar manipulator I have to deal with.
The first two moves are rotational and the third one is a prismatic one. The shoulder and elbow move around the X-axis, while the forearm moves forward and backward a distance "a" (d3).
I did all the direct and inverse kinematics, including the Jacobian. I think the third move around x is not done correctly.
Here is a picture about the x-y-z-axis and the DH Table we made:
I've seen an answer about this subject but I can't even understand that one. On the image you can see there are my two attempts, but neither of them worked for me.