Application of Gap Metric to LADRC Design in Multilinear Model of SDR

Abstract

The solid ducted rocket ramjet (SDR) system faces many disturbances in the process of operation, and the linear active disturbance rejection controller (LADRC) has been widely used in engineering to solve such problems. However, the SDR also has strong nonlinearity, which brings a great challenge to the application of the LADRC in the gas flow regulation of the SDR. And the problem of fast adjustment of the “compensation factor” is one of the main difficulties in LADRC. In this paper, under the LADRC frame, the gas generator system’s closed-loop stability of the SDR was analyzed and the range of compensation factors had been calculated, and then, the “gap factor” was introduced and the “cross-iteration” method was used to quickly map out the “compensation factor” in the multilinear model controller based on the variation of the zero-point position of the system and the gap metric between adjacent set points. This greatly simplifies the parameter tuning process of the LADRC when it was applied to strongly nonlinear systems. Finally, through the comparison of simulation with adaptive PI controller and model-assisted LADRC (M-LADRC), the results have shown that the control method designed in this paper can obtain satisfactory performance and has a good engineering application prospect.

Hybrid Modeling Method of SDR Interstage Valve Based on Mechanism and Data-Driven

“…Specifically, the oscillation of the valve causes a change in the throat area, resulting in different degrees of congestion and ultimately a change in the GG's (gas generator) pressure. The variation of pressure will modify the burning rate of the propellant, which in turn will cause the gas flow to the throat and the ram combustor (RC) to change, and the secondary combustion of the gas with the intake air will produce different thrusts [2,3]. Although the SDR system is simple in structure, its operating boundary is narrow.…”