Analog Implementation of a Fractional-Order PID Controller for the T200 Thruster Using a Novel Lattice Type Structure

Abstract

The T200 thruster is a widely used propulsion system for autonomous underwater vehicles (AUVs); however, achieving high-performance control with low energy consumption remains a challenge due to inherent system nonlinearities and uncertainties. Fractional-order PID (FOPID) controllers offer enhanced flexibility and robustness compared to classical PID structures, making them well-suited for such complex dynamic systems; however, their practical analog realization and algorithm-based parameter optimization remain limited in the existing literature. This paper presents a unified control-hardware co-design framework for the T200 thruster by combining metaheuristic optimization, FOPID control theory, and low-power analog circuit design. Within this framework, a transfer function of the T200 thruster is obtained from experimental input-output data, and the parameters of the FOPID controller are optimized using multiple metaheuristic algorithms to enhance dynamic performance. A novel lattice-type circuit structure is then introduced for the analog implementation of the optimized FOPID controller. Comparative performance evaluation using transient response criteria and a series of statistical analysis methods demonstrates that the Salp Swarm Algorithm provides the most consistent and effective tuning results, yielding a well-damped closed-loop response with zero overshoot, improved transient behavior, and strong robustness against disturbances and parameter variations. SPICE simulations of the proposed lattice-type analog implementation show close agreement with MATLAB-based control results while achieving low power consumption of 22.902 mu W and reliable operation under process, voltage, temperature, and noise variations. These results confirm the feasibility and advantages of algorithm-optimized FOPID controllers for next-generation marine robotic systems in which high-precision control and low power consumption are crucial.