Research on the nonlinearity correction method for the piezoelectric optical scanner in a lidar system

The laser scanning system of a lidar usually needs a laser scanner with characteristics such as fast linear scanning, small size and small rotational inertia moment. Traditional laser scanners, such as galvanometer and rotating multi-faceted mirror, are difficult to achieve fast linear scanning with low moment of inertia. In order to solve these problems, a piezoelectric optical scanner based on novel piezoelectric actuator is designed in this paper. First of all, the scanner system components based on self-learning feed-forward controller is introduced. Furthermore, the principle and method of amending the scanner hysteresis loop are analyzed. Finally, one-dimensional linear scanning in a wide range of frequencies using the control platform with the core of digital signal processor TMS320F2812 is achieved. The experimental results show that the hysteresis characteristics have been restrained and scanning linear performance of the piezoelectric optical scanner has been remarkably improved in low frequencies. In high frequencies, the nonlinearity of triangle wave scanning is reduces by adding a notch filter circuit which restrained the structure resonance of the scanner. The piezoelectric optical scanner also has other advantages such as large optical scanning angle, high first step resonance frequency, small size and simple structure.