There are two different conventions that can determine DH parameters. What is the difference between Craig's [1, Sec 3.4] convention and the Spong [2, Sec. 3.2] convention? I know that both methods must have the same response.
: Craig, John J. Introduction to robotics: mechanics and control. Addison-Wesley, 1989.
: Spong, Mark W., Seth Hutchinson, and Mathukumalli Vidyasagar. Robot modeling and control. Wiley, 2006.