New parametric affine modeling and control for skid-to-turn missiles

This paper presents a new practical autopilot design approach to acceleration control for tail-controlled STT (skid-to-turn) missiles. The approach is novel in that the proposed parametric affine missile model adopts acceleration as the controlled output and considers the couplings between the forces as well as the moments and control fin deflections. The aerodynamic coefficients in the proposed model are expressed in a closed form with fittable parameters over the whole operating range. The parameters are fitted from aerodynamic coefficient look-up tables by the function approximation technique, which is based on the combination of local parametric models through curve fitting using the corresponding influence functions. In this paper, in order to employ the results of parametric affine modeling in the autopilot controller design, we derived a parametric affine missile model and designed a feedback linearizing controller for the obtained model. Stability analysis for the overall closed loop system is provided, considering the uncertainties arising from approximation errors. The validity of the proposed modeling and control approach is demonstrated through simulations for an STT missile