A Robust Adaptive Control with Extended State Observer for a Piezo-actuated Nano-positioner

Positioning control of a nano-positioner driven by a piezoelectric actuator is discussed. Robust adaptive control with extended state observer is presented for the trajectory tracking control. Radial basis function neural network (RBFNN) is utilized to estimate the unknown nonlinearities. Extended state observer (ESO) is also taken to observe the total disturbance, which includes external disturbances and hysteresis. Both the RBFNN and the ESO are utilized to reduce the dependence on model information. A nano-positioner model is established. Simulations confirm the robust adaptive control with ESO is effective in improving positioning accuracy.