Hello,

I am new to industrial manipulators and I have maybe a silly question. Can anyone explain me why we should transform the theta parameter in DH algorithm (such as in the atteched photo) to the robot's physical angles? And what is the meaning of robot's physical angles?

Thank you!

Dear Maria

It has to do with the Manufacture´s convention on were the angles si measure from (were is the zero) and positive/negative direction

For joint 2 for example most manufacturers use Link 2 vertical position as the zero location

Hence the DH parameter requires an adjustment of 90 degrees to account for the rotation transformation from the horizontal plane to the vertical plane

That is why the formula adds Pi/2 to the theta value