I am looking the name of an anime tv series and heres the story...
3 kids find their selfs in a space ship and in it there are 3 robots.So these guys are the only ones who can control it and find some bad guys to help a prinsess and her people.There is one more robot like a ninja and one of the kids can call him using a dagger or something.That's all that i remember =) Anyone can help me find what is the name of it?

one of the kids can call him using a dagger or something.

Sounds like the Green Ranger to me :P ;-)

Unfortunatly though, i've never actually heard of what you're describing. Sorry.

thats not enough, said more so i can understand .

ok here is what i remember =)
These three people are the only ones that can control the robots, so they travel with a spaceship which has a princess in it.When they fight and they are in trouble an other robot (ninja) comes to help them.In one episode one of the heros finds(i think) a dagger and with that he calls the ninja and merges with him.So one of the robots stays unused and the forth guy that is with them learns to use the robot that the other guy had before he could call the ninja

sounds familiar............ hey! I have seen it! It was on a couple of years ago, wasn't it? I'm no good with names, but I'll try and remember it for you

ok =)