Polyphony Digital and Sony AI studied how AI can learn to drive fast in Gran Turismo.
AI in video games can be a bit unpredictable, especially in the past. All players can remember when an NPC has crashed into a wall or made things hell by not doing something they were supposed to do, like helping the player. Enemy AI has been constantly improving, especially in shooters, as enemy NPCs will now swarm and target the player with the most intelligence, and actively avoid being shot, instead of standing in front of shots like idiots in the days of yore .
The AI in the driving game tends to be a bit simpler, especially since the competing cars are tied to a race track and they don’t have to do more complicated things like show you an open world, for example. In recent years, cars stubbornly followed a line around a race track and ignored what the player was doing. However, in the latest racing games, like Forza Horizon 5, the AI is more realistic. Depending on the difficulty, rival cars may attempt to close your racing lines and even push and hit you, as a human player would, with more aggressive tactics.
However, Gran Turismo has never really been known for its spectacular AI. In older entries in the venerable series, competitors often appeared to be following a line around a race track. Polyphony Digital is known for a lot of things – insanely detailed car models, a fair amount of real automakers, decent graphics, but they’re not the most recognized when it comes to artificial intelligence.
But things may be changing. Polyphony Digital collaborated with a Sony division called Sony AI for research work exploring the possibilities of artificial intelligence in car driving in Gran Turismo. The only thing about this AI attempt was that the artificial intelligence in question was using visual cues to learn to drive.
Human players, of course, use a lot of those cues, things like the turns of a race track, the UI dashboard showing speed and braking, and force feedback. The lead author of the paper, Ryuji Imamura, set out the conditions under which the AI would use the same signals that a human driver could use to learn to drive fast.
The AI finally learned how to achieve lap times that were within the top 10 percent of human players. However, it took several hundred laps for the AI to reach this level. But when it did, it drove 4.5 seconds faster than the average human and 3.3 seconds slower than the fastest human.
Sony AI explores different uses of AI and is a fairly new subdivision of Sony. An earlier study on Gran Turismo, by August 2020, saw his AI using a method known as reinforcement learning to learn to run on a track. That study involved only physical interactions, such as when driving routes involved collisions and slower lap times. However, he finally achieved a ‘superhuman’ performance, beating even the best Gran Turismo Sport drivers by one lap.
The new AI is much better than the actual AI deployed in the Gran Turismo game that PlayStation players are used to. GT Sport’s own AI is 9.5s slower than the visualized AI from the last study. If Polyphony Digital decides to use some of this AI in its latest title, the upcoming Gran Turismo 7, then human players might need to start honing their racing skills. The full AI study article can be found. here.