Position control system via active disturbance rejection for laser optical systems

Y In this work, an active disturbance rejection control scheme for a laser beam stabilization system is presented in a pragmatic way. First, a linear extended state observer is designed, which allows estimating external disturbances, non-model dynamics, and the transverse displacement speed of the beam. Subsequently, a control law is proposed for regulation and tracking tasks. The stability analysis in the input-to-state-stability framework shows that the closed-loop system, plant-observer-controller is stable when the total disturbance is viewed as the input, and the state is the beam position error. This analysis presents new perspectives to a now-classic result. The experimental results show the performance of the control scheme. Using the L-2 norm and the Integral of the squared error, the closed-loop performance is evaluated and compared with three controls generally used in this type of systems: PID, observer-based state feedback, and linear quadratic gaussian regulator.