Depth Control of an Underwater Sensor Platform: Comparison between Variable Buoyancy and Propeller Actuated Devices

Area of Science:

• Marine engineering
• Robotics
• Oceanography

Background:

• Underwater long-endurance platforms are essential for continuous oceanic observation and data collection.
• Efficient depth control is critical for the performance and mission success of underwater vehicles.
• Understanding energy consumption trade-offs in actuation systems is vital for optimizing underwater platform design.

Purpose of the Study:

• To investigate and model the energy consumption of variable buoyancy and propeller-actuated depth control systems for underwater vehicles.
• To analyze the relationship between control accuracy and energy efficiency for different actuation mechanisms.
• To provide insights for optimizing depth control strategies in underwater applications.

Main Methods:

• Development of a detailed vehicle model incorporating nonlinearities like saturations and sensor quantization.
• Modeling and simulation of two distinct actuation systems: variable buoyancy and propeller-driven.
• Implementation and testing of Proportional-Integral-Derivative (PID) controllers to evaluate dynamic response and power requirements.

Main Results:

• The study presents a linear-based model that accounts for system nonlinearities and estimates energy consumption for both actuation methods.
• Simulations demonstrate that propeller-actuated systems generally offer higher control accuracy compared to variable buoyancy systems.
• Variable buoyancy systems show lower energy consumption, highlighting a trade-off between energy efficiency and control precision.

Conclusions:

• The findings offer valuable insights into the energy consumption characteristics of different depth control actuation systems for underwater vehicles.
• The research supports informed decision-making in selecting appropriate actuation mechanisms based on mission requirements for energy efficiency and control accuracy.
• This work contributes to the optimization of long-endurance underwater platforms for sustained oceanic observation.