The various hands are still a work in progress, he noted. The tire-changing video was made when “we were using the old hands and not the new hands, and they did not quite have the dexterity to thread the nut onto the bolt in a way that it doesn’t cross the thread.”

Darpa also set out tasks that it hopes to accomplish during the next phase. One example is to design a robot arm and hand that can search for an improvised explosive device, or I.E.D., by touch. The challenge would be to program a hand that could open the zipper on a gym bag and then go through the bag and recognize objects by touch.

The agency is also financing research groups in two other categories. It has selected the National Robotics Engineering Center at Carnegie Mellon University, NASA’s Jet Propulsion Laboratory and the University of Southern California to continue development of high-level software for the next generation of robot arms.

Until recently, the agency asked software developers to develop robotic programs for generic individual motions, like moving forward or backward; now it has set out to simply have the robots perform a specific task.

“You could say things like pick up the bottle, unlock the door, tasks like that,” Dr. Pratt said. The agency began with six teams and held a “bake-off” in which it chose three teams to continue in the last phase of the project.

In the software project, Darpa supplied each team with a standard hand that it then programmed.

“The grasping tasks were done so well that we believe that for the kinds of objects we had them pick up — ranging from a ball to a rock to tools like hammers — we don’t need to do further work in grasping,” Dr. Pratt said.

Manipulating grasped objects was a more challenging task, he said, and one on which the teams would continue to do research. The program is financed for 18 more months.