Dynamic hysteresis modeling and control of piezoelectric actuator based on H∞ robust disturbance observer

Hysteresis nonlinearity, which is an inherent characteristic of piezoelectric actuators (PEAs), decreases the tracking precision and may even result in limit cycle oscillations. A tracking control based on H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</inf> robust disturbance observer (DOB) is presented for PEAs in this paper. Hammerstein system is applied to modeling dynamic hysteresis nonlinearity of PEA. Then, a control scheme that combines H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</inf> robust DOB with inverse compensator is designed for PEA considering bounded exogenous disturbances and model uncertainties. Trajectory tracking control experimental results show that the proposed controller is effective. Compared with conventional DOB (CDOB), it is shown that H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</inf> robust DOB can achieve higher tracking accuracy as well as stronger robustness simultaneously.