From Gineipaedia, the Legend of Galactic Heroes wiki
Artificial gravity is one of the primary technologies used in modern spacecraft engineering. It can be used to produce a gravitational field on spacecraft of almost any size.
Artificial gravity technology was developed sometime between the 27th and 28th century, and helped to usher in the Galactic Federation's golden age of exploration and colonisation alongside the other Three Graces. (Legend of Galactic Heroes Volume 1: Dawn)
Apparent characteristics and limitations
Spacecraft appear to be capable of generating artificial gravity fields of approximately 1G; this technology must be rather compact, as it can be employed on very small vessels; artificial gravity tech also appears to be extremely reliable, as there are no recorded instances of it failing to function due to combat or accidental damage.