The deadlock between several American universities and the State Department over visits by a Soviet professor was broken when the department "clarified" its restrictions on the visits so the universities would accept them.

The dispute is one of several in recent months involving academic freedom and national security between the universities, particularly Stanford, and the government. It began when Stanford announced it would refuse to restrict the activities of a Soviet visitor, Nickolay V. Umnov, a specialist in computerized walking robots.

The University of Wisconsin followed suit, and said it would not accept the State Department's restrictions, while Ohio State University said through a spokesman it would reduce Umnov's time on campus from six weeks to three days if the restrictions were required. An Auburn University spokesman complained about the restrictions but said Umnov would still be welcome on his scheduled spring visit.

But yesterday the National Academy of Sciences, which runs the U.S.-Soviet exchange program, announced that the deadlock had been broken after some negotiation, and Umnov's visit may again be possible.

Professor Bernard Roth, who will be Umnov's host at Stanford, said "clarified" is the term being used to save face for the State Department. Actually, he said, "It was a total turnaround by the State Department. I don't want to embarrass anyone, but it was."

He said that "since all of my research and, indeed, all of the research conducted at Stanford University is unclassified, the State Department's restrictions do not appear to preclude access to any of our research programs."

Stanford Vice Provost Gerald Lieberman said the new "clarified" restrictions "would not inhibit his Umnov's access to any activities at Stanford."

The restrictions originally had said that "Umnov's program should be restricted to mechanical theory of robotic locomotion. No access should be permitted to control units or programming techniques for robots."

Now, Umnov will be allowed to see control units or programming techniques if they are unclassfied and have been or will be published in scientific papers or talks. All work and equipment at Stanford is in this category, a spokesman said.

The agreement, according to Stanford officials, also absolves Stanford of responsibility for policing Umnov's activities outside the campus. Umnov is prohibited from visiting industrial plants.

"Our restrictions have not been withdrawn. They have been clarified somewhat," a State Deparment official said. He added that Umnov's visit may now be possible.