Adaptive Control of Electro-hydraulic Servo System with Dead-zone Nonlinearity Based on Popov Criterion

The dead zone phenomenon occurs in electro-hydraulic servo system,the output of such systems corresponding to a sinusoidal input contains higher harmonic besides the fundamental,which causes the system output distortion and has effects on system analysis.To compensate for the system,a model reference adaptive control(MRAC) design was proposed based on Popov criterion,it can cancel the dead-zone effect for improving output tracking.Stability analysis shows that the adaptive scheme can eliminate the tracking err fast.As illustrated in a simulation example,with the proposed MRAC controller,the transient response of the compensated system can be improved and accurate tracking can be achieved.