Tracking scheme of airborne star tracker based on event-triggered sliding mode control with known input delay

Area of Science:

• Aerospace Engineering
• Control Systems

Background:

• Airborne star trackers are vital for aircraft navigation, but their performance suffers from environmental disturbances and limited computational resources.
• Existing control strategies often fail to address these challenges simultaneously.

Purpose of the Study:

• To propose a novel event-triggered sliding mode control (ET-SMC) scheme for airborne star trackers.
• To address disturbances and computational limitations in star tracking control under known input time delay.

Main Methods:

• An extended state observer (ESO) estimates airborne disturbances.
• A novel ET-SMC scheme with an event-triggering mechanism based on ESO error enhances robustness and resource utilization.
• A new sliding gain reduces chattering and improves adaptability.

Main Results:

• Lyapunov theory confirms system stability, reachability of the sliding surface, and practical sliding mode existence.
• The ultimate upper bound of system states is proven, considering input time delay.
• Zeno behavior is excluded, validating the feasibility of the proposed ESO-based ET-SMC.

Conclusions:

• The proposed ET-SMC method demonstrates superior robustness, disturbance attenuation, tracking accuracy, and computational efficiency.
• This approach leads to more stable star tracker performance, enhancing precise aircraft navigation.