Their drivetrain is a 4-wheel swerve drive.
They have 2 Globe Motors controling the direction of all 4 wheels.
Then they have a drill motor/tranny powering each side of the drivetrain. The tricky part is how they do this. They use these drill tranny’s to spin a shaft mounted vertically through the wheels. This then spins a bevel gear (not shown) which powers the wheels forward and reverse.
By doing this, they are able to drive and swerve their wheels with a minimum of motors and gears. (4 motor, 4 wheel swerve)
I’m not from 998, nor have I heard any details concerning their drivetrain. This is just my speculation based on my past FIRST/Design experience.
I don’t mean to steal any of their thunder, but I think this is a very cool, and elegant design. I thought it might merit some explanation.