Barrier Lyapunov function based adaptive finite-time control for hypersonic flight vehicles with state constraints

Area of Science:

• Aerospace Engineering
• Control Systems Theory
• Nonlinear Control

Background:

• Hypersonic flight vehicles (HFV) present complex control challenges due to high speeds and stringent operational requirements.
• Existing control strategies often struggle to guarantee finite-time convergence and handle state constraints effectively.
• Ensuring robust tracking performance under actuator saturation and state limitations is critical for HFV safety and mission success.

Purpose of the Study:

• To investigate and develop a finite-time tracking control strategy for hypersonic flight vehicles (HFV) subject to state constraints.
• To address the challenges posed by strict working conditions and potential signal saturation in HFV.
• To ensure the finite-time convergence of tracking errors and system states.

Main Methods:

• Development of a control-oriented model for HFV enabling adaptive backstepping.
• Application of barrier Lyapunov functions to constrain tracking errors within desired bounds.
• Design of piecewise saturation functions to manage virtual signal limitations.
• Implementation of an adaptive scheme based on finite-time stability theory for guaranteed convergence.
• Utilization of a sliding mode differentiator for accurate estimation of virtual control law derivatives.
• Introduction of novel auxiliary systems to mitigate saturation effects and maintain finite-time stability.

Main Results:

• The proposed adaptive backstepping control scheme successfully constrains tracking errors using barrier Lyapunov functions.
• Piecewise saturation functions effectively restrict virtual signals, adhering to operational limits.
• The adaptive scheme ensures finite-time convergence of the HFV's dynamic states.
• Auxiliary systems effectively compensated for saturation effects, preserving finite-time stability.
• Numerical simulations validated the effectiveness and superior performance of the developed control strategy.

Conclusions:

• The presented finite-time tracking control method provides a robust solution for hypersonic flight vehicles with state constraints.
• The integration of barrier Lyapunov functions and adaptive control ensures precise and stable tracking performance.
• The approach effectively handles signal saturation, enhancing the overall reliability of HFV control systems.