Analysis and simulation of the longitudinal control of an unmannedaerial vehicle

摘要

Analyses the performance of a longitudinal controller for thenARMOR UAV (unmanned aerial vehicle) RC (robust control) model, submittednto gust disturbances. The final aim of the analysis is a practicalnsolution to be implemented in the ARMOR UAV microprocessor. We explorenthe difficulties that may arise from competitive specifications derivednfrom the actual aircraft characteristics. In order to control thenlongitudinal model of the ARMOR UAV, a robust controller was designed innagreement with the traditional requirements of good tracking of speednand altitude, but taking into account the characteristics of the realnactuators. Essentially, the engine installed turns out to be a poornactuator, both in terms of time constant and in allowable thrust, andnits operation easily reaches the limitations. In terms of gust response,nthe comparison of open and closed loop, in terms of frequency analysis,ndemonstrates that the altitude control is achieved, but no furthernimprovement is obtained. The time simulations are in perfect agreementnwith the previous results and don't exhibit any influence due to thennonlinear characteristics. Finally, the changes of physical parametersnare perfectly transparent to the controller, except for the phugoid zonenwhere the gust sensitivity behaves like in open loop. The properties ofnthe robust controller design have thus been verified, but the quality ofnthe actuators, and particularly the engine, appear to be of greatnimportance for a good gust disturbance control