Fixed-time adaptive prescribed-performance sliding-mode control for space manipulators with actuator uncertainties

Area of Science:

• Robotics and Control Systems
• Aerospace Engineering
• Applied Mathematics

Background:

• Space manipulators face complex challenges including external disturbances, uncertainties, and actuator faults.
• Achieving precise and robust tracking control under these conditions is critical for mission success.
• Existing control methods may struggle with rapid convergence and guaranteed performance bounds.

Purpose of the Study:

• To develop a fixed-time adaptive tracking control scheme with prescribed performance for space manipulators.
• To ensure both transient and steady-state performance under various operational challenges.
• To enhance robustness against unknown disturbances, uncertainties, and actuator faults.

Main Methods:

• Introduction of an enhanced prescribed performance function for performance bounds.
• Construction of a non-singular fast terminal sliding-mode surface based on tracking error.
• Development of a model-based fixed-time control strategy, followed by an adaptive law to estimate and compensate for uncertainties.
• Rigorous stability analysis using Lyapunov theory.

Main Results:

• The proposed control scheme achieves rapid convergence and high tracking accuracy.
• Demonstrated robustness against bounded external disturbances, parametric uncertainties, and actuator faults.
• Fixed-time stability and prescribed performance compliance were rigorously proven.
• Effectiveness validated through numerical simulations and experimental results on a space manipulator.

Conclusions:

• The developed fixed-time adaptive prescribed-performance control is effective and superior for space manipulators.
• The approach successfully addresses challenges like disturbances, uncertainties, and faults.
• It offers a promising solution for high-performance space robotic operations.