To create a stable cryptocurrency that is both decentralized and non-collateralized is hard. You would need 2 requirements, measuring the exchange rate in a decentralized way, and controlling the coin supply. Both of these are difficult to make.
https://blog.ethereum.org/2014/11/11/search-stable-cryptocurrency/
This blog by Vitalik Buterin kind of summarizes this and provides some solutions that are not perfect. Do you have any suggestions?