The Dinobots were created by Wheeljack after learning about the facinating and powerful prehistoric creatures that used to roam the Earth. He built them alternate modes that resembled dinosaurs, however the Autobots were trapped on Earth at the time and had no access to Vector Sigma, the supercomputer used to create new transformer personalities. Wheeljack tried to program personalities himself, but even with his vast technical knowledge the Dinobots' logic processes were primative and immature.
The Dinobots were built on a radical departure from standard Autobot design, which allowed them to be equipped with Decepticon anti-grav units. This makes the Dinobots some of the few Autobots that can fly.
Most Autobots have mixed feelings about their Dinobot allies. While the dinos are powerful warriors always eager to battle the Decepticons, they are also violent, unpredictable, and don't seem to care about protecting the citizens of Earth.
Witwicky World universe
Without Spike's inspiration, the Dinobots are never built.
The Dynobots were build by Shockwave millions of years ago, but rebelled against him and disappeared, presumed destroyed.