Nonlinear Feedback Control and Stability Analysis of a Proof-of-Work Blockchain
Geir E. Hovland, Jan Pavel Kucera · Modeling Identification and Control A Norwegian Research Bulletin · 2017
In this paper a novel feedback controller and stability analysis of a blockchain implementation is developed by using a control engineering perspective.The controller output equals the difficulty adjustment in the mining process while the feedback variable is the average block time over a certain time period.The computational power (hash rate) of the miners is considered a disturbance in the model.The developed controller is tested against a simulation model with constant disturbance, step and ramp responses as well as with a high-frequency sinusoidal disturbance.Stability and a fast response is demonstrated in all these cases with a controller which adjusts it's output at every new block.Finally the performance of the controller is implemented and demonstrated on a testnet with a constant hash rate as well as on the mainnet of a public open source blockchain project.