Design of two-dimensional piezoelectric laser scanner system for precision laser beam steering.

In this work, a large aperture two-dimensional (2D) piezoelectric laser scanner system with an onboard sensor to detect the scanner's deflection angle has been designed and prototyped. The proposed 2D laser scanner is driven using three amplified piezoelectric actuators assembled in an equilateral triangle configuration to provide structural stability and compactness. To overcome the nonlinearity that derives from the hysteresis effect of the piezoelectric actuators, the tip-tilt principle and the control schemes of the 2D scanner are analyzed and compared. Thanks to the combination of onboard sensing of the deflection angle of the scanner with the closed-loop control capability, this 2D scanner's features include a large aperture and high accuracy. The experimental results demonstrate that closed-loop control achieves higher control accuracy than the open-loop control approach, leading to a reduction in the relative error from 2%-4% to ∼0.5%, while the deflection angle tracking accuracy lies approximately within the 40 μrad range.