I am studying the Denavit Hartenberg and to practice I am using the following manipulator:
I have been able to assign some of the frames almost correctly, but i did some mistakes I cannot understand. First of all, the correct solution for this manipulator is:
now, in my attemps, I did some mistakes, which are the following.
In the first place, I did not use the frame zero as the frame of the prismatic joint, which is the first joint, bit I decided to define a frame 1 for it, but this is wrong apparently, but why? , to me it seemed natural to define this additional frame.
Another mistake I have done is to not let coincede frame 1 with frame 2, but also in this case I defined an additional frame, which is wrong.
So, I have a problem understanding how to say when I can define two frames in the same point and when not.
How do I understand when to to this?
So, to be as clear as possible, my question is:
How do I assign the origin of the frames in the Denavit Hartenberg convention and how do I know if two frames have the same origin?