Developing a mathematical model for the steering channel of a space rocket stage and studying effects of hydraulic forces in the steering engine on its stability

The paper presents results of developing a simplified mathematical model for the steering channel of a space rocket stage using approximation of non-linear hydraulic properties of two-throttle electrohydraulic amplifier of the steering engine by the method of multidimensional cubic spline-interpolation-extrapolation. A distinctive feature of the method that was developed consists in that mathematical simulations do not require complex analytical dependences of the properties, but rather only tabular representation of experimental data is used for their approximation in the course of calculation. The high efficiency of multidimensional approximation methods based on the cubic spline-interpolation-extrapolation of properties presented in this paper has been proven and demonstrated in mathematical models of steering channels of systems for controlling the thrust vector of main engines on rocket stages. It is demonstrated that an increase in hydraulic force applied to slide valve plungers of the electrohydraulic amplifier by the flow of the liquid around them in a statically stable steering actuator cannot result in self-induced oscillation, that is, does not affect its dynamic stability, but rather only changes its transient response.