Modern multivariable and multi-loop digital redesign of missile autopilots

The paper presents plant input mapping digital redesign methods for the digital implementation of missile autopilots. Performances of multivariable and multi-loop digital redesigns as applied to a nominal continuous-time autopilot system are studied. A multivariable digital redesign takes the multi-input, multi-output closed-loop system and directly transforms it into a multivariable sampled-data control system whereas a multi-loop digital redesign discretizes each feedback loop using a single-input, single-output technique, from the inner-most loop to the outermost loop. Both methods take into account the plant and topology of the control system. Numerical simulations indicate that the sampled-data missile autopilot obtained with the multivariable digital redesign method yields, in general, the best performances.