Design of a Bio‐Inspired Miniature Submarine for Low‐Cost Water Sampling and Monitoring in Shallow‐Water Environments

Water sample and monitoring is essential for protecting aquatic ecosystems and detecting environmental pollution. This paper presents the design and experimental validation of a bio‐inspired miniature submarine for low‐cost water sample and monitoring. Inspired by the jet propulsion mechanism of squids, the proposed system employs pump‐driven water jets for propulsion and steering, combined with a pump‐based buoyancy control mechanism that enables both depth regulation and water sampling. The vehicle integrates low‐cost, commercially available components including an ESP32 microcontroller, IMU, pressure sensor, GPS receiver, and LoRa communication module. The complete system can be constructed at a hardware cost of approximately $122.5, making it suitable for educational and environmental monitoring applications. Experimental validation was conducted through pool tests and field trials in a lake. During a 360° rotation test, roll and pitch deviations remained within ±2° and ±1.5°, respectively, demonstrating stable attitude control. Steering experiments showed a heading step response with approximately 2 s rise time and 5 s settling time. Depth control experiments achieved a target depth of 2.5 m with steady‐state error within ±0.1 m. Field experiments further demonstrated reliable navigation and successful water sampling operations. The results confirm that the proposed platform provides a compact, stable, and cost‐effective solution for small‐scale environmental monitoring in shallow‐water environments.