Hypersonic tracking control under actuator saturations via readjusting prescribed performance functions

Area of Science:

• Aerospace Engineering
• Control Systems Theory
• Nonlinear Control

Background:

• Prescribed performance control (PPC) effectively manages system specifications but struggles with actuator saturation-induced errors.
• Existing PPC methods lack the ability to readjust performance functions, leading to error peaking.

Purpose of the Study:

• To propose a novel PPC scheme for hypersonic flight vehicles that addresses actuator saturation.
• To eliminate the singularity problem in traditional PPC by enabling adaptive readjustment of performance functions.

Main Methods:

• A readjusting-performance-function-based approach with adaptive terms to constrain velocity and altitude tracking errors.
• A novel compensated system (CS) for velocity dynamics, extended to the altitude subsystem as a high-order formulation.
• Optimal control protocols using adaptive dynamic programming.

Main Results:

• The proposed method successfully constrains tracking errors within prescribed bounds, even under actuator saturation.
• The singularity problem inherent in traditional PPC is eliminated.
• Simulation results demonstrate the advantages of the novel PPC scheme over baseline controllers.

Conclusions:

• The novel PPC scheme effectively handles actuator saturation in hypersonic flight vehicles.
• Adaptive readjustment of performance functions ensures robust tracking performance.
• The approach offers a significant improvement for controlling systems with performance limitations.