While this animated fellow looks like something out of NBA 2K18, it’s really an AI that’s learning how to dribble in real time. The AI starts out fumbling the ball a bit and by cycle 95 it is able to do some real Harlem Globetrotters stuff. In short, what you’re watching is a human-like avatar learning a very specialized human movement.
To do this researchers at Carnegie Mellon and DeepMotion, Inc. created a “physics-based, real-time method for controlling animated characters that can learn dribbling skills from experience.” The system, which uses “deep reinforcement learning,” can use motion capture date to learn basic movements.
“Once the skills are learned, new motions can be simulated much faster than real-time,” said CMU professor Jessica Hodgins.
Once the avatar learns a basic movement, advanced movements come more easily including dribbling between the legs and crossovers.
From the release:
A physics-based method has the potential to create more realistic games, but getting the subtle details right is difficult. That’s especially so for dribbling a basketball because player contact with the ball is brief and finger position is critical. Some details, such as the way a ball may continue spinning briefly when it makes light contact with the player’s hands, are tough to reproduce. And once the ball is released, the player has to anticipate when and where the ball will return.
The program learned the skills in two stages — first it mastered locomotion and then learned how to control the arms and hands and, through them, the motion of the ball. This decoupled approach is sufficient for actions such as dribbling or perhaps juggling, where the interaction between the character and the object doesn’t have an effect on the character’s balance. Further work is required to address sports, such as soccer, where balance is tightly coupled with game maneuvers, Liu said.
The system could pave the way for smarter online avatars and even translate into physical interactions with the real world.
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