use this
<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
android:duration="500"
android:fromYDelta="0%"
android:interpolator="@android:anim/accelerate_interpolator"
android:toYDelta="-100%" />
here interpolator : An interpolator defines the rate of change of an animation. This allows the basic animation effects (alpha, scale, translate, rotate) to be accelerated, decelerated, repeated, etc.