Multichannel method for frequency analysis of digital relay electromechanical system for controlling thrust vector of liquid-propellant rocket engine

The paper examines the feasibility of using a multichannel method of autointegration with full averaging of Fourier coefficients for calculating amplitude-phase-frequency characteristics of the digital electromechanical system for controlling thrust vector of a liquid-propellant rocket engine. The proposed version of the autointegration method is based on numerical integration of systems of non-linear differential equations of the math model of the system with monoharmonic inputs at fixed frequencies and analysis of periodic responses to these inputs using Fourier method. Integration process at each of the fixed frequencies continues until the average values of Fourier coefficients for the harmonic that is being studied in the output periodic response of the system to a monoharmonic input over the elapsed number of periods of the monoharmonic input signal become sufficiently constant. The proposed algorithm for the monoharmonic autointegration method uses as the sufficiency criterion for the Fourier coefficients constancy the comparison between average values of Fourier coefficients for the harmonic under study in the output periodic signal of the system that are obtained during the last period of the input monoharmonic signal and the average value of the same Fourier coefficients during the second to last period. The proposed version of the monoharmonic autonintegration method with full averaging of Fourier coefficients makes it possible to calculate amplitude-phase-frequency characteristics to the specified accuracy and in minimal time.