Parallel Feedforward Compensation in Simple Adaptive Contr ol for a Winged Re -entry Vehicle

This paper continues the study of a Model Reference Adaptive Control implementation for maintaining closed -loop stability of a winged re -entry vehicle . Th e control -system design makes use of Simple Adaptive Control theory, which aims at tracking the output of a refer ence model. A previous paper explore d ways for analysis of passivity conditions in a very large non -linear plant. As the analysis show ed that the plant does not satisfy the sufficient passivity conditions, ways to fulfill those conditions are proposed thro ugh the use of parallel feedforward. Sensitivity analysis is applied to compare the robustness of designs with and without parallel feedforward. The inverse of a PD feedback controller serves well as parallel feedforward compensator, and gives a slightly t ighter bound on the control error and the control effort. And, fulfilling the sufficient conditions, in theory the robustness of system stability is guaranteed.