LAUSR

Nanopositioning stages driven by piezoelectric actuator have been employed across a wide spectrum of applications. However, the challenging issues they are suffering include hysteresis and creep effects, along with lightly damped mechanical resonances. In view of these issues, this article presents a novel hierarchical antidisturbance control solution. The proposed strategy seamlessly integrates three antidisturbance components, i.e., a feedforward-type disturbance observer (DO), a feedback-type DO, and an error-based active disturbance rejection controller (EB-ADRC) into a single framework. Such a strategy loosens the bandwidth constraint of DO imposed by mechanical resonance and speeds up the response time of typical ADRC without relying on high-order derivatives of reference input. The inclusion of these antidisturbance components does not complicate the controller tuning procedure. In fact, it is shown that only one parameter needs to be tuned in practice. Moreover, the stability analysis of EB-ADRC is provided within DO framework. The superior control performance of the proposed strategy is confirmed via extensive comparative studies with integral resonant control, positive position feedback, and linear active disturbance rejection control strategies.