ROBUST SLIDING MODE CONTROL OF A MOVING-MASS ACTUATED SUBORBITAL REENTRY BIOLOGICAL PAYLOAD

摘要

This paper deals with the robust sliding mode control of a suborbital reentry biological payload utilizing moving-mass actuators. In a biological payload that is under the study in this investigation, reentry rate regulation is one of the critical issues must be solved. Because of nonlinear time-varying dynamics of this payload and presence of high aerodynamic disturbances during reentry phase as well as inherent model uncertainties, choosing an appropriate stabilizing and control mechanism can be a challenging engineering problem. Moving-mass actuation is an innovative concept introduced recently to control of reentry vehicles with great advantages over traditional aerodynamic control methods. The present research develops a novel four-degree-of-freedom model of a suborbital biological payload in a vertical plane with one moving-mass actuator. Subsequently, sliding mode control is invoked to regulate the time-varying payload body rates during reentry phase despite inherent model uncertainties and aerodynamic disturbances. The asymptotic stability and robustness of the proposed sliding mode based control system is proved using direct method of Lyapunov. Finally, effectiveness of the proposed moving-mass control system for rate regulation of a suborbital biological payload during reentry phase is demonstrated through numerical simulations.