Improved dynamic event-triggered anti-unwinding control for autonomous underwater vehicles

This article investigates an improved adaptive dynamic event-triggered control scheme for autonomous underwater vehicles (AUVs) under the quaternion-based attitude representation. The main innovation in this paper is to improve the dynamic event-triggered (DET) algorithm, which makes the trade-off between the control performance of the AUV system and the communication frequency in the controller-to-actuator (CA) channel easier to be achieved. Primarily, to describe the attitude representation of the AUV in a unique form, a unified auxiliary variable confining the scalar quaternion's initial error value is developed to avoid the potential unwinding phenomenon. Subsequently, based on the unified auxiliary variable, an event-based adaptive control law is tactfully designed to mitigate the adverse effects of lumped external perturbations and unknown model dynamics. Moreover, by introducing the modified trigger adjustment algorithm, the trigger frequency can be adapted to the performance requirements of the AUV system at different evolutionary stages. Finally, theoretical analysis and numerical simulations are presented to demonstrate the stability and effectiveness of the provided method.