Fixed-time fault-tolerant attitude control for rigid spacecraft with torque saturation

Area of Science:

• Aerospace Engineering
• Control Systems Theory
• Nonlinear Control

Background:

• Spacecraft attitude control is critical for mission success.
• Existing methods struggle with input saturation, actuator faults, and system uncertainties.
• Achieving fixed-time stability remains a significant challenge.

Purpose of the Study:

• To develop a fixed-time attitude control strategy for spacecraft.
• To address challenges posed by input saturation and actuator faults.
• To enhance the robustness and performance of spacecraft attitude control systems.

Main Methods:

• Design of three novel saturated fixed-time nonsingular terminal sliding mode surfaces (NTSMSs).
• Introduction of time-varying NTSMSs with dynamic adjustment parameters for saturation handling and attitude dynamics cancellation.
• Development of a saturated control scheme combined with a novel saturated reaching law.
• Application of Lyapunov stability theory for theoretical validation.

Main Results:

• The proposed NTSMSs ensure fixed-time stability of system states after sliding manifold establishment.
• The dynamic adjustment parameter effectively handles input saturation and cancels attitude dynamics.
• Simulation results demonstrate the effectiveness and superiority of the developed control scheme.
• A modification strategy enhances practical engineering applicability.

Conclusions:

• The novel control scheme provides robust fixed-time attitude stabilization for spacecraft.
• The methods effectively mitigate the impact of input saturation and actuator faults.
• The research contributes advanced solutions for challenging spacecraft control problems.