I have always had difficulties getting all students to do their homework too. Can you make worksheets? If you give your students a complete the picture page, a word jumble with vocabulary, an idea generator (something simple and fun) they will be more apt to do it. Open ended answers that are short and basic review will help you plan lessons after you grade it. Give a reward for doing it, like four in a row and they can chew gum in class (teachers in my building give lollipops- though I don't do this) or a sticker or free choice day. If they clean up early they could do their homework right in class too.
Good Luck, ALi