Adaptive super-twisting sliding mode altitude trajectory tracking control for reentry vehicle

Area of Science:

• Aerospace Engineering
• Control Systems Theory
• Nonlinear Control

Background:

• Reentry vehicles face complex altitude trajectory tracking challenges due to bounded uncertainties.
• Conventional super-twisting sliding mode control (STSMC) offers robustness but can suffer from chattering and requires prior knowledge of uncertainties.
• Existing methods often struggle with precise tracking accuracy and rapid convergence under dynamic conditions.

Purpose of the Study:

• To develop a continuous adaptive super-twisting sliding mode control (ASTSMC) for reentry vehicle altitude trajectory tracking.
• To enhance tracking accuracy and control performance while mitigating the chattering phenomenon.
• To achieve faster convergence and improved robustness compared to conventional STSMC methods.

Main Methods:

• Development of a novel continuous adaptive super-twisting sliding mode control (ASTSMC) by integrating adaptive gain techniques with STSMC.
• Utilization of a fast power rate reaching law and a modified fast nonsingular terminal sliding mode (FNTSM) surface.
• Finite-time stability analysis of the closed-loop system using Lyapunov theory.

Main Results:

• The proposed ASTSMC method effectively improves tracking accuracy and overall control performance for reentry vehicles.
• Adaptive gain technique eliminates the need for prior uncertainty information and reduces control gain overestimation, thereby alleviating chattering.
• The controller demonstrates faster convergence and superior robustness compared to conventional STSMC, validated by simulation results.

Conclusions:

• The developed ASTSMC provides a robust and accurate solution for altitude trajectory tracking control of reentry vehicles under bounded uncertainty.
• The method's ability to adapt to unknown uncertainties and suppress chattering makes it highly suitable for practical aerospace applications.
• Simulation results confirm the finite-time stability and enhanced performance of the proposed control strategy.