SAN FRANCISCO — Ford Motor is spending $1 billion to take over a robotics startup to acquire more of the expertise needed to reach its ambitious goal of having a fully driverless vehicle on the road by 2021.

The big bet announced Friday comes just a few months after the Pittsburgh startup, Argo AI, was created by two alumni of Carnegie Mellon University’s robotics program, Bryan Salesky and Peter Rander.

Salesky formerly worked on self-driving cars at a high-profile project within Google — now known as Waymo — and Rander did the same kind of engineering at ride-hailing service Uber before the two men teamed up to launch Argo late last year. Argo had been considering whether to raise money from venture capitalists, the conventional fundraising channel for startups, before opting to become an independent subsidiary of Ford instead.

Ford is spreading its $1 billion investment over a five-year period.

The alliance between Argo and Ford aims to combine the spunk and dexterity of a technologically savvy startup with the financial muscle and manufacturing know-how of a major automaker.

The unusual deal marks the next step in Ford’s journey toward building a vehicle without a steering wheel or brake pad by 2021 — a vision that CEO Mark Fields laid out last summer.

The decision to turn to Argo for help is a tacit acknowledgment that Ford wouldn’t be able to pull it off on its own.

If Argo’s system turns out to be far ahead of anything else on the market, the subsidiary could eventually be worth substantially more than it is now. Argo employees, who will work from offices in Pittsburgh, Michigan and the Silicon Valley, will be given stock in the subsidiary as part of their compensation packages.