ANALYSIS OF ACCURACY OF NONLINEAR CONTROL SYSTEMS OF MULTI-ROTOR UAVS UNDER STATIONARY RANDOM SIGNALS

Abstract

A large number of articles and monographs are devoted to the development of linear control systems for multi-rotor UAVs, in which, based on the methods of the modern theory of automatic regulation and control, the problems of choosing the regulators that provide the required performance indices and stability margins of UAVs’ control systems are considered, taking into account structural and parametric uncertainties , nonlinearities of separate channels, various external control and disturbing signals, including deterministic and random signals, etc. At the same time, there are practically no works that study the issues of analyzing the dynamic accuracy of nonlinear control systems for multi-rotor UAVs under random external signals, for example, wind gusts, etc.

In the article, based on the approximate method of statistic linearization, an engineering technique for analyzing the accuracy of nonlinear UAVs’ control systems with PID controllers in separate channels under stationary random signals with a Gaussian probability distribution and non-zero mathematical expectations are considered. It is shown that the use of the statistic linearization method allows reducing the accuracy analysis of the of independent nonlinear control channels of UAVs to a joint analysis of the accuracy of two different linear systems with respect to the mathematical expectation and the centered random component of the input signal. Analysis of the accuracy of each of these linear systems is carried out by known methods of classical control theory. A numerical example of the analysis of statistical accuracy of the control system  of a quadcopter with saturation-type nonlinearities in the measuring devices of the system is given.