Design of cascade active disturbance rejection guidance law for miniature strapdown guided munition

Strapdown seeker is generally used in miniature guided munitions, which leads to the problems of model uncertainty and stability degradation in the guidance system. In this paper, a cascade linear active disturbance rejection control (CLADRC) method is studied. The first-stage active disturbance rejection controller is used to suppress the angular rate of munition-target line of sight. The linear extended state observer (LESO) is used to estimate and dynamically compensate the uncertainty of munition model, and the proportional-differential controller is used to calculate the observed value and the input value to obtain the control quantity. The obtained control command is observed through the acceleration feedback by the munition model in the second-stage ADRC, which can ensure the overload value is less than the maximum available overload of the munition. The simulation results show that the line-of-sight angular rate is well suppressed, the overload at the end of trajectory meets the requirements, and the target can be intercepted accurately.