Active disturbance rejection control of servo platform using improved nonlinear control law

A new kind of nonlinear control law is proposed for the purpose of improving servo platform tracking performance under condition of rapid movement. On the basis of linear ADRC, an arctangent function is selected, and smoothly extended to an anti-S curve. The new method retains the feature of estimating and compensating the internal un-modeled dynamics and external disturbances. Simulation and comparison tests show that system using new control method has faster and more accurate tracking results.