Asymmetric integral barrier Lyapunov function-based dynamic surface control of a state-constrained morphing waverider with anti-saturation compensator

To satisfy wide-speed and long-range mission requirements, morphing aircraft can maintain optimal flight performance by changing their configuration during flight. As an advanced morphing aircraft, a cross-domain morphing waverider can change its wing geometry to maintain a high lift-to-drag ratio across the subsonic, transonic, and supersonic to hypersonic speed ranges. During the highly dynamic morphing process, the trajectory tracking problem of the morphing waverider is characterized by strong coupling, time-varying characteristics, parameter uncertainties, input saturation, and asymmetric state constraints. To address these problems, this paper proposes an asymmetric integral barrier Lyapunov function (AIBLF) based dynamic surface controller consisting of two loops, based on the six-degrees-of-freedom partial decoupled control-oriented model of a symmetric-sweep-wing morphing waverider. Specifically, a virtual control signal of three-axis angular rates is provided by the AIBLF-based flight controller to satisfy the predefined asymmetric constraints of the angle of attack, sideslip angle, and bank angle, combined with a disturbance observer to approximate the disturbances of multiple parameter uncertainties. Subsequently, the desired virtual control signal consisting of three-axis angular rates is derived by passing the above virtual control signal through a nonlinear adaptive filter to avoid the problem of complexity explosion. The control command is generated by the dynamic surface controller and a finite-time anti-saturation compensator to overcome input saturation. Additionally, a nonlinear disturbance observer is applied to estimate the lumped disturbance to realize feedforward compensation. According to the stability analysis, all signals in the closed-loop system are uniformly ultimately bounded while the states remain in the constraint sets. Finally, the performance of the proposed controller is evaluated through extensive and comparative numerical simulations under multiple disturbances. The proposed controller has a small tracking error and high convergence speed and can prevent states from exceeding the given bounds.