Predefined-time Lyapunov function-based sliding mode control for spacecraft rendezvous and docking

Area of Science:

• Aerospace Engineering
• Control Theory
• Robotics

Background:

• Spacecraft rendezvous and docking (R&D) is critical for space missions.
• Existing control methods face challenges with external disturbances, actuator faults, and saturation.
• Ensuring rapid and reliable R&D requires advanced control strategies.

Purpose of the Study:

• To develop a robust predefined-time control strategy for spacecraft R&D.
• To address the impact of external disturbances, actuator faults, and saturation.
• To enhance the practical applicability and efficiency of R&D control.

Main Methods:

• Developed a relative motion model incorporating gravity gradient torque and J2 perturbations.
• Proposed a novel Lyapunov function with predefined-time stability properties.
• Designed a predefined-time sliding mode controller and a control torque redistribution scheme.

Main Results:

• The proposed controller ensures system states converge within a specified predefined time.
• The control strategy demonstrates robustness against external disturbances, actuator faults, and saturation.
• The torque redistribution scheme optimizes actuator workload and energy consumption.

Conclusions:

• The developed predefined-time sliding mode controller is effective for spacecraft R&D.
• The strategy offers enhanced performance and robustness compared to existing methods.
• The approach is generalizable to other nonlinear control problems.