Moving Platform Troubles

I was trying to make a moving platform for the player to ride. So I used the First Person Game Controller, it lands on the platform just fine, but when I look below me I realize that the platform is really choppy looking. It is jumpy. I used a quaternion to make it rotate towards the next point, it is constantly going in a circle. I would also prefer to make it just move back and forth without rotating. How do I do that? Thanks in advance!