I don't understand how many people still didn't figure it out.
Madara said it clearly, he will take obito's place as the juubi's jinchuriki using hashirama's senjutsu to stop obito. When he said that, he pulled out a black rod.
We know that rinnegan users can use those black rods to manipulate a body, leaving or dead. To use it, they pierce the "object's" body with the black rod, thus gaining control of it.
Given the situation, I think it's easy to understand that what madara wants is to control hashirama via black rods in order to use hashirama in SM to fight and injure obito. This is his plan, most likely. At least it was, as the situation changed again in a way madara probably didn't expect.
However, his intention is still to become the juubi's jinchuriki. Don't forget this.