Fully Actuated System Approach-Based Prescribed Time Fault-Tolerant Control and Hierarchical Structure Avoidance Collision for Multiple Unmanned Helicopters

For 6-DOF unmanned helicopters subject to actuator faults, convergence-rate constraints, and collision-avoidance requirements, a prescribed-time fault-tolerant control strategy is proposed in this paper. Primarily, to prevent the faulty unmanned helicopter from affecting other normal individuals, an upperlayer virtual agent system prescribed-time control protocol is developed based on the fully actuated system approach. Simultaneously, the artificial potential field is incorporated into the control protocol to establish a hierarchical interaction mechanism, enabling collision avoidance during flight missions. Subsequently, the newly presented prescribed-time sliding mode controller can enable the position subsystem to track the reference signals within the designer-defined time. In addition, a prescribed-time filter is constructed to generate the derivative of the attitude angle. Building upon this filter, the event-triggered mechanism, and fully actuated system approach, a prescribed-time fault-tolerant control tactic for the attitude subsystem is established to reduce the signal transmission burden. Finally, the theoretical results of the proposed control strategy are validated through a simulation example and a comparative experiment.