Abstract
This study is concerned with the attitude control problem of variable-structure near-space vehicles (VSNSVs) with time-varying state constraints based on switched nonlinear system. The full states of vehicles are constrained in the bounded sets with asymmetric time-varying boundaries. Firstly, considering modeling uncertainties and external disturbances, an extended state observer (ESO), including two distinct linear regions, is proposed with the advantage of avoiding the peaking value problem. The disturbance observer is utilized to estimate the total disturbances of the attitude angle and angular rate subsystems, which are described in switched nonlinear systems. Then, based on the estimation values, the asymmetric time-varying barrier Lyapunov function (BLF) is employed to construct the active disturbance rejection controller, which can ensure the full state constraints are not violated. Furthermore, to resolve the ‘explosion of complexity’ problem in backstepping control, a modified dynamic surface control is proposed. Rigorous stability analysis is given to prove that all signals of the closed-loop system are bounded. Numerical simulations are carried out to demonstrate the effectiveness of the proposed control scheme.
Highlights
The near-space vehicle (NSV) is one type of novel aerospace vehicle, which cannot only make a supersonic cruise in the atmosphere, and perform multiple missions outside the atmosphere
The active disturbance rejection control (ADRC) scheme, based on extended state observer (ESO), can be an effective way to weaken the influence of external disturbances and modeling uncertainties
The state and extended state in the ESO system are both three-dimensional vectors to guarantee that the ESO can be directly applied in the attitude angle and angular rate subsystems of variable-structure near-space vehicles (VSNSVs)
Summary
The near-space vehicle (NSV) is one type of novel aerospace vehicle, which cannot only make a supersonic cruise in the atmosphere, and perform multiple missions outside the atmosphere. By combining the constrained control method and radial basis function neural networks, a new adaptive backstepping controller was proposed for NSVs with parametric uncertainties, external disturbances and input nonlinearities [6]. Zhang et al [11] proposed a controller based on a switching linear parameter-varying framework for the tracking problem of flexible hypersonic vehicles. Yu [22] proposed a novel adaptive output feedback control for nonlinear systems with constant state constraints by utilizing command-filtered backstepping and state observer. The active disturbance rejection control (ADRC) scheme, based on extended state observer (ESO), can be an effective way to weaken the influence of external disturbances and modeling uncertainties. There is little extant literature on the application of ADRC technology in switched nonlinear systems, and ADRC combined with time-varying asymmetric BLF brings challenge to controller design.
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