The Articles of Confederation were meant to preserve the independence of the new colonies. It was an agreement between them that ultimately formed a very loose federal government. The point of this was that the federal government possessed powers given to them only by the agreement between the colonies. One primary purpose of the Articles of Confederation was to guide the colonies throughout the Revolutionary War.
The problem with the Articles of Confederation was that the colonies soon realized the federal government needed the ability to do more. For instance, the federal government was extremely weak when dealing with several uprisings, such as Shay's Rebellion. These very observable weaknesses proved valuable, however. The U.S. Constitution followed the Articles of Confederation and was able to remedy many of the problems the loose agreement initially had.