Berserker Prime — Fred Saberhagen

Master storyteller Fred Saberhagen continues his Berserker series, detailing humanity's war with the dreaded Juggernaut-like machines programmed to destroy all life in the galaxy.
In the Twin World planets, Prairie and Timber, Plenipotentiary Gregor is determined to serve his government. Even if it means executing innocent Huvean hostages, invaders from another planet. And even though Gregor's granddaughter, Luon, is in love with Reggie, a Huvean.
But now the Berserkers are threatening the Twin Worlds, crashing a scoutship, capturing the planets' president, and reprogramming his brain to suit their violent agenda. And only the Huveans, in a desperate reprieve, can save the Twin Worlds' populace from annihilation.