Fast adaptive robust control of electro-hydraulic servo system

Electro-hydraulic servo systems (EHSSs) have been widely used in industrial and military applications for their high power-to-size ratio and the ability to supply huge force. However, precise control of EHSSs cannot be easily obtained due to their inner nonlinearity and parameter uncertainty. Variable load is another factor to decrease the tracking performance of EHSSs. Indirect adaptive robust control (IARC) was proposed to improve the tracking performance of EHSS, but due to the poor parameter adapting speed, IARC can be further improved to have better performance. Traditional projection type parameter estimation algorithm is redesigned to increase the adapting speed when parameter is changed. A fast adaptive robust control (FARC) is then proposed to speed up the parameter adapting speed, so that a better tracking performance of FARC is maintained. Simulation results show that the proposed FARC gives an improved tracking performance and a faster parameter adaptation.