Robust H(∞) control for spacecraft rendezvous with a noncooperative target.

Area of Science:

• Aerospace Engineering
• Control Systems Theory
• Robotics

Background:

• Spacecraft rendezvous and proximity operations are critical for missions like servicing and debris removal.
• Noncooperative targets pose significant challenges due to unpredictable motion and lack of communication.
• Existing control methods often struggle with uncertainties and real-world constraints like actuator saturation.

Purpose of the Study:

• To develop a robust H(∞) control approach for autonomous spacecraft rendezvous with noncooperative targets.
• To address uncertainties in orbital parameters and target mass.
• To ensure reliable chaser spacecraft guidance despite control input saturation, measurement inaccuracies, and thrust errors.

Main Methods:

• Modeling the relative motion between chaser and target as an uncertain system.
• Designing a robust H(∞) controller incorporating finite-time performance objectives.
• Utilizing linear matrix inequality (LMI) techniques to derive controller synthesis conditions.

Main Results:

• A robust H(∞) controller was successfully designed to handle system uncertainties and performance requirements.
• The controller demonstrated effectiveness in driving the chaser spacecraft for rendezvous.
• Sufficient conditions for controller existence were derived using LMI technology.

Conclusions:

• The proposed robust H(∞) control strategy is effective for spacecraft rendezvous with noncooperative targets.
• The methodology accounts for critical real-world constraints and uncertainties.
• The LMI-based approach provides a systematic way to synthesize the robust controller.