Moving platform smooth unles I am standing on it then jerky

Anyway to avoid this?

Using simple script to move a box:

#pragma strict
function Start () {
}
function Update () {
transform.Translate(Vector3.back * .02);
}

Box moves nice and smooth unless I am standing on it then is has a jitter that just looks terrible.

Thanks!

CZ

 

When on the platform make the platform the parent of the player using transform.parent.