Previously, the Berkeley lab had received international attention for training a robot to fold laundry. Although it was viewed almost one million times on YouTube, the laundry-folding demonstration noted that the video had been sped up more than 50 times. The new videos show the robots performing tasks at human speeds.

Despite their progress, the researchers acknowledge that they are still far away — perhaps more than a decade — from their goal of building a truly autonomous robot, such as a home worker or elder care machine that could perform complex tasks without human supervision.

The researchers said that while their new approach represents an important leap, it is also fragile. For example, the bottle cap-threading technique will work reliably when the bottle is moved from one location to another or if the bottle is of a different color. But if the bottle is tilted at an angle before it is picked up, the robot will completely fail.

“There is nothing better to ask a roboticist, ‘If you change the conditions, will it still work?’ ” Dr. Abbeel said.

To explain the new approach, the researchers draw the analogy of how baseball players track and then catch balls. Humans do not do mathematical calculations to discern the trajectory of the ball. Rather, they fix the ball in their field of vision and adjust their running speed until they arrive at the spot where the ball lands.