Variable structure control of time-delay systems with a simulation study on stabilizing combustion in liquid propellant rocket motors
The dynamical model of combustion in liquid propellant rocket motors is an unstable time-delay system. It is known that when it is stabilized by a linear state feedback controller, the robustness of the closed loop system is not satisfactory. Here, a variable structure control approach to stabilize the combustion is presented. It is shown that a switching functional, instead of a switching function, should be used for variable structure control systems with delays occurring in state variables and/or control inputs. A design method for the switching functional leading to stable sliding models has been presented for spectrally controllable systems. The variable structure controller have been obtained using a reaching law. The key idea of the approach is to transform retarded systems into non-retarded ones by using characteristic matrices of linear time-delay systems. The theory presented is applied to the stabilization of combustion in a liquid monopropellant rocket motor, and satisfactory results have been obtained by a simulation study.
scientific article; zbMATH DE number 806688