Precision control of piezo-actuated optical deflector with nonlinearity correction based on hysteresis model

• An modified asymmetric PI model is presented to depict the hysteresis behavior.
• A hybrid control method is used to precisely control the angle of optical deflector.
• Tracking performance of the optical deflector is improved significantly.

The hysteresis nonlinearity of piezoelectric actuator is one of the main defects in the control of optical deflector which is widely used as a key component in adaptive optics system. In this paper, a control method combining the feedforward and feedback controllers is proposed to precisely control the deflection angle of an optical deflector. The inverse of an asymmetric Prandtl-Ishlinskii (PI) hysteresis model is utilized in the feedforward loop, and a PID controller is used in the feedback loop. Then, a tracking control experiment for the desired triangle wave was performed. From the experimental results, we can see that the response of the optical deflector is linearized and the positioning precision of optical deflector is significantly improved.