Yao Xuliang

Investigation of thrust and load characteristics of AUV propeller under the condition of different angle incoming flow

Under the influence of the sea current, the hydrodynamic performance of the propeller varies with the changing of the incoming flow direction. Aiming to obtain the hydrodynamic performance accurately, the thrust and load characteristic of AUV propeller is investigated under the conditions that different angles incoming flow go through the plane of propeller. First, the visual-physical model is built and gridded in the CFD software. The open water hydrodynamic performance of propeller is calculated in the CFD software, based on the standard turbulent model. The consistency between the calculated results and the experimental/theoretical results shows the practicability and validity of the CFD method. Then, the incoming flow angle range is set from 0° to 25°. The thrust force and load torque of propeller is calculated in the CFD software under the condition of steady incoming flow velocity but different incoming flow angle. Lastly, we can see that the propulsion force and torque of propeller will increase with the increasing of the incoming flow angle, where the maximum value would increase 75% compared with the initial case based on the analysis of the calculated results. This hydrodynamic performance is proposed for the design of the AUV propulsion control strategy. And this computed results could be the reference index when choose the rated power of the propulsion motor.

Constrained generalized predictive control for propulsion motor of autonomous underwater vehicle

In order to suppress the effect of near-surface autonomous underwater vehicles (AUV) propulsion motor torque ripple caused by marine environment change, generalized predictive control (GPC) is used to deal with brushless DC motor speed control in this paper. Due to the complicated working environment and load characteristics of propeller, in practice, the motor can only work in a certain performance range. So the CARIMA model was established, and an improved algorithm considering the input constraints across short control horizon was proposed. Meanwhile error correction part was added. Simulations were made for dynamic propeller load of near-surface-sailing AUV. The simulation results show that the amount of constrained optimized calculation can be effectively reduced by the improved GPC algorithm considering the constraints. The dynamical performance and robustness can also be improved, and the energy consumption can be effectively reduced.

Research on lift feedback fin stabilizer system and its intelligence controller

A lift feedback fin stabilizer is a new kind of fin stabilizer, which is the most effective ship roll reducing equipment. The defects of a fin angle feedback fin stabilizer are discussed, the control principle and an improved design of lift feedback fin stabilizer are given, and finally, the PID neural network controller is proposed in this paper.