# Development of a Multifunctional Unmanned Boat Platform for Aquaculture Automation
## 2 Complete Machine Structure and Working Principle
### Platform Structure and Details
#### 2.1.1 Hull Structure  
The hull structure is the foundation of the unmanned boat. Its design directly affects the stability and reliability of the platform. In aquaculture, unmanned boats need to operate in various water conditions. These conditions include calm ponds and open waters with wind and waves. A well-designed hull must ensure stability and buoyancy in the water. It must also consider the durability for long-term use and maintenance costs. This is especially important for small-scale farmers, where cost control and operational simplicity are critical. Based on these considerations, the hull is fabricated using EVA foam boards. EVA foam boards are inexpensive, have good buoyancy, and are corrosion-resistant [15]. These properties make EVA foam boards suitable for long-term use in seawater environments. The overall hull design is streamlined to reduce water resistance. This improves sailing speed and stability. The bottom of the boat has chamfered corners. This minimizes lateral tilting and rocking in waves, enhancing the stability of the hull. The hull structure is divided into two layers. The upper layer is the sensor layer. It mainly houses development boards and sensors required for the underwater vision module and the environmental data acquisition module. This includes the NodeMCU development board, the NeZha development board, the pH sensor, the temperature sensor, the TDS turbidity sensor, and the underwater camera. The lower part of the hull includes the bait chamber and the motion control module. The bait chamber is placed in the front for adding and dispensing bait. The motion control module is installed in the rear for powering and controlling the boat's movement. To improve airtightness and waterproofness, all electronic devices on the lower level are installed in waterproof boxes. Additional protection is provided by sealing strips. Batteries and other key components are installed at the bottom of the boat. This lowers the center of gravity and improves stability in the water. The specific placement structure is shown in Figure 2.  
The functional modules of the UBP can be divided into the following seven parts: perception, planning, control, interaction, communication, payload, and navigation (Figure 3). Among them, the perception module is used to collect data from underwater sensors, such as water temperature, pH value, and TDS value. Underwater cultures are recognized through underwater cameras, combined with computer vision and machine learning. The navigation module provides real-time position estimation and trajectory planning based on GPS, BDS, and other technologies. The planning module is based on the Monte Carlo simulation to plan the cruise path and evaluate the water quality in the aquaculture area. The control module is based on the generation of low-level control commands to ensure navigation stability. The communication module is used for data exchange between the unmanned boat and the user and other devices. The interaction module carries out