Dynamics enhancement of galvanometer laser scanners by adaptive inverse control

Galvanometer laser scanners are high-performance rotary motors for optical applications and are often utilized in production engineering. The dynamic properties of current scanner systems do not always fulfill the desired requirements. The controler-based solutions that have been presented in the past years primarily concentrate on changes in operation points or simple trajectories and neglect to address general trajectory tracking. This becomes a crucial issue in many production processes. In this article, a modification of adaptive inverse control applied to scanner systems to improve the dynamics and simultaneously address parameter and environmental changes is presented. An online identification of the system via an LMS-algorithm delivers an adaptive model of the PID-stabilized galvanometer drives. An inversion based feed-forward controller is designed, to improve dynamics and suppress eigenmovements, e.g. overshooting. The performance is verified by an experimental setup in which the error is reduced by almost 90 % for the chosen example, compared to a state of the art scanner system.