Roll control for single moving-mass actuated fixed-trim reentry vehicle considering full state constraints

Moving-mass control system applies internal movable mass elements as actuators to shift the center of mass of the vehicle relative to the external aerodynamic forces to generate control torques. Although moving-mass control system provides sufficient control authority, it suffers from its nature of nonlinear and high-coupling. What's more, the design of the moving-mass control system confronts state constraints arising from two aspects: (1) physical limitation: the internal space of the vehicle is limited and the moving-mass element can not translate out of the shell; (2) performance requirements: limiting the maximum velocity of the moving-mass element can decrease the disturbances exerting on the vehicle significantly. Based on the purpose of controlling the roll attitude of a moving-mass actuated vehicle without violating any state constraint, we design a controller using integral barrier Lyapunov functionals to control the system and keep all the states bounded in the meanwhile. The backstepping procedure is adopted and the dynamic surface control scheme is applied to avoid the 'terms explosion' in that procedure. An adaptive law is proposed to diminish the influences caused by uncertainties whose boundaries are unknown. The performance of the proposed controller is illustrated by numerical simulations under various conditions.