Sliding mode based trajectory linearization control for hypersonic reentry vehicle via extended disturbance observer

Area of Science:

• Aerospace Engineering
• Control Systems Theory
• Nonlinear Dynamics

Background:

• Hypersonic reentry vehicles (HRVs) face complex attitude tracking challenges due to atmospheric uncertainties and system nonlinearities.
• Existing control strategies often struggle with chattering, control constraints, and accurate disturbance rejection.

Purpose of the Study:

• To develop a novel hybrid control framework for robust attitude tracking in HRVs.
• To improve control accuracy and reduce control consumption.
• To address tracking errors and ensure stability under uncertainties and constraints.

Main Methods:

• A hybrid control framework combining observer-based sliding mode control (SMC) with trajectory linearization control (TLC).
• Integration of a nonlinear tracking differentiator (TD) for reduced control consumption.
• Employment of a novel SMC with an extended disturbance observer (EDO) and a new sliding surface incorporating estimation error.

Main Results:

• The proposed framework achieves chattering-free, high-accuracy attitude tracking for HRVs.
• The extended disturbance observer (EDO) demonstrates effective counteraction of uncertainties, with validated dynamic response, noise tolerance, and estimation accuracy.
• Finite time convergence stability theory confirms the closed-loop system's stability.

Conclusions:

• The hybrid SMC-TLC framework offers a robust and effective solution for HRV attitude tracking.
• The integration of TD and EDO significantly enhances performance and stability under challenging conditions.
• Simulation results validate the superiority of the proposed control strategy over existing methods.