For the design and verification of a motion control algorithm for unmanned surface vehicles, a simulation system is developed based on VRX and Simulink. Firstly, considering the effect of wind, a dynamic model of the USV with podded propellers is established. Secondly, combined with speed control, three control modes are considered, including yaw rate control, heading control, and path-following control, and speed, heading, yaw rate, and path guidance controllers are designed. Then, a real-time simulation system is developed based on the Virtual RobotX (VRX) environment and the Simulink ROS2 toolbox. Finally, motion control simulation experiments under three control modes and a path-following water tank experiment are carried out. The designed simulation system can simulate the motion of USVs and different environmental elements, such as wind, intuitively and realistically. In simulation experiments, the designed controllers can make the USV follow commands quickly and accurately under three control modes. In the water tank experiment, the USV could stably track the desired path with a relatively small tracking error. Therefore, the effectiveness of the simulation system is strongly confirmed through simulation experiments and the water tank experiment. The simulation system will be expanded in the future for more research on target recognition, path planning, and other aspects of USVs.

To meet the development requirements of the path planning unit for unmanned underwater vehicles (UUVs), research is conducted on UUV 3D obstacle avoidance path planning algorithms and software design. Firstly, aiming at the problem of underwater 3D obstacle avoidance path planning for UUVs, a global path planning algorithm based on the improved D* Lite is designed, and a local path planning algorithm combining the 3D obstacle avoidance strategy and the improved artificial potential field (APF) algorithm is designed. Secondly, based on the above path planning algorithms, a UUV 3D obstacle avoidance path planning software is developed under the Robot Operating System 2 (ROS2) framework and deployed on an Orange Pi 5B. To test the algorithms and the developed software, a UUV autonomous navigation hardware-in-the-loop (HIL) simulation system is constructed. Finally, based on this system, three types of HIL simulation experiments are conducted, including global path planning, local path planning, and comprehensive obstacle avoidance path planning. The simulation experiments show that the improved D* Lite-APF algorithm has better comprehensive performance than the traditional D* Lite-APF algorithm; the path planning software can guide the UUV to reach the goal point safely and runs stably and reliably. The designed UUV 3D obstacle avoidance path planning algorithm and software exhibit good obstacle avoidance performance and can be applied to the rapid development of actual UUV path planning units.