Distributed adaptive fault-tolerant close formation flight control of multiple trailing fixed-wing UAVs

Area of Science:

• Aerospace Engineering
• Control Systems Theory
• Robotics

Background:

• Cooperative control of multiple unmanned aerial vehicles (UAVs) faces challenges from actuator faults and aerodynamic effects like wake vortices.
• Ensuring reliable formation flight for trailing UAVs, especially in the presence of disturbances, is critical for mission success.

Purpose of the Study:

• To develop a robust distributed adaptive fault-tolerant control (FTC) scheme for multiple trailing fixed-wing UAVs.
• To enable trailing UAVs to maintain desired relative positions with respect to a leader UAV under actuator faults and wake vortex conditions.

Main Methods:

• A distributed adaptive fault-tolerant control (FTC) scheme integrating a sliding-mode estimator, dynamic surface control, neural networks, and disturbance observers.
• Utilizing a distributed architecture to handle individual UAV faults and environmental disturbances.
• Employing adaptive control techniques to compensate for uncertainties and faults.

Main Results:

• The proposed FTC scheme successfully guides all trailing UAVs to converge to the leader UAV, maintaining pre-defined time-varying relative positions.
• The control system effectively mitigates the adverse effects of wake vortices generated by the leader UAV.
• It ensures reliable operation even when a subset of trailing UAVs experiences actuator faults.
• Tracking errors for all trailing UAVs are demonstrated to be bounded, confirming system stability.

Conclusions:

• The developed distributed adaptive FTC scheme provides a reliable solution for cooperative control of fixed-wing UAVs facing actuator faults and wake vortices.
• The approach ensures robust formation keeping and accurate relative positioning under challenging operational conditions.
• Simulation results validate the effectiveness and superiority of the proposed control strategy over existing methods.