After a month in the center of the legislature's volatile debate over the future of state prisons, Del. Frank C. Robey, the stocky, square-jawed high school principal who heads the House Appropriations' corrections subcommittee, could afford to feel contented this week.

After a weekend of intensive bargaining, Gov. Harry Huges had finally been persuaded to back the construction of a new 500-bed prison in Baltimore. As a result, Hughes' other legislative proposals, emphasizing rehabiliation and community-based prison facilities, seemed likely to overcome legislative opposition previously thought to be overwhelming.

And Robey -- who just two weeks ago was jolted by charges from his colleagues that he was too protective of Hughes' corrections policy and public safety chief Gordon Kamka -- had emerged as a chief architect of the compromise.

"I think this situation has proven me to a lot of doubting Thomases," the Baltimore City delegate concluded as he reclined in his office the night the compromise was announced. "I see what I did as making possible all the things that Hughes and Kamka wanted by making them politically realistic."

What Robey did was to make the Hughes' plans for community rehabilitation centers for convicts, renovations of existing prisons in Jessup and pre-release programs more palatable to his fellwo delegates by helping to persuade the governor to do what he had vehemently opposed doing -- building a new medium-maximum security prison.

Now, satisfied that there will be more space to house state convicts while still responding to a judge's order to reduce the overcrowding of existing prisons, conservative delegates, Robey says, can feel more secure in approving Hughes' plans.

The controversy and delicate bargaining that preceeded the new corrections plan -- and the heated debate that is undoubtedly still to come on it -- have become almost a yearly routine in the legislature for Robey since he assumed control of the Appropriations Law Enfrocement and Transportation Subcommittee four years ago.

As a chief manager of the House review of corrections and transportation budgets, Robey has been called upon to shape -- then defend to his colleagues -- some of the most controversial programs the General Assembly has considered.

In 1976, for example, Robey had to defend the Baltimore subway package from the attacks or rural interests, and this year, will help manage the campaign for funding for the Washington-area Metro.

These tasks, combined with the three-year-old controversy over siting and funding for prisons, have made Robey's subcommittee work his dominant interest here, gaining him considerable attention that has both helped and hurt him.

The respect and expertise Robey has gained as a budget manager have made him, at 33, a possible candidate for a statewide office like comptroller, or for a slot in Balitmore as a state senator or congressman.

At the same time, Robey has made enemeies more quickly than other ambitious delegates who restrict themselves largely to their own bills and proposals, rather than taking a leadership role in committee work. Some of his colleagues now say that Robey is both too personally arrogant and too willing to be coaxed by the administration or the leadership.

But Robey, who is offended by such criticism, nevertheless says that he enjoys working at the center of the legislature's major issues.

"I'm something of a workaholic down here," he says. "I have to take a leave without pay every year from my job as a principal to work here. So if I'm going to do that, I want to try to do the most as a legislator that I can.

"I'm in a situation now where I can have a real impact on programs, and be effective and responsive as a legislator while still being a high school principal. I'm very content with that."