GVF-MPC Depth Control Framework Motivated by Restoring-Moment Mechanism Analysis for Bionic Robotic Fish

TY - JOUR

T1 - GVF-MPC Depth Control Framework Motivated by Restoring-Moment Mechanism Analysis for Bionic Robotic Fish

AU - Han, Jiarong

AU - Yuan, Xiangqing

AU - Yin, Bo

AU - Liu, Yu

AU - Zou, Suli

AU - Deng, Zhihong

AU - Ma, Zhongjing

N1 - Publisher Copyright: © 2026 IEEE.

PY - 2026/5/1

Y1 - 2026/5/1

N2 - Longitudinal oscillations are commonly observed in depth control of low-speed underwater platforms such as bio-inspired robotic fish. To investigate this issue, this letter conducts a quantitative analysis of the vertical-plane dynamics. It reveals the speed-dependent coupling between the depth and pitch channels as the swimming speed decreases, and clarifies the underdamped mechanism induced by restoring-moment dominance. A critical speed condition for the onset of low-speed oscillations is also derived. Based on the dynamic analysis, a hierarchical GVF-MPC depth control framework is proposed, which structurally decouples geometric guidance from dynamic execution. The guidance layer employs a guiding vector field (GVF) to generate naturally smooth attitude references from geometric information, with reduced sensitivity to model degradation and pitch disturbances. The inner loop applies model predictive control (MPC) to track the guidance commands while explicitly accounting for dynamic constraints, balancing convergence speed and control-input smoothness to improve stability and safety under low-speed conditions. Simulation and experiments are conducted to evaluate the effectiveness and robustness of the proposed method. Simulations consider sinusoidal and V-shaped depth path and compare the proposed approach with LOS, PID, and SMC based controllers. Experiments are performed in still water and under simulated Sea-State 1 disturbances to assess steady state accuracy, disturbance recovery, and overall robustness.

AB - Longitudinal oscillations are commonly observed in depth control of low-speed underwater platforms such as bio-inspired robotic fish. To investigate this issue, this letter conducts a quantitative analysis of the vertical-plane dynamics. It reveals the speed-dependent coupling between the depth and pitch channels as the swimming speed decreases, and clarifies the underdamped mechanism induced by restoring-moment dominance. A critical speed condition for the onset of low-speed oscillations is also derived. Based on the dynamic analysis, a hierarchical GVF-MPC depth control framework is proposed, which structurally decouples geometric guidance from dynamic execution. The guidance layer employs a guiding vector field (GVF) to generate naturally smooth attitude references from geometric information, with reduced sensitivity to model degradation and pitch disturbances. The inner loop applies model predictive control (MPC) to track the guidance commands while explicitly accounting for dynamic constraints, balancing convergence speed and control-input smoothness to improve stability and safety under low-speed conditions. Simulation and experiments are conducted to evaluate the effectiveness and robustness of the proposed method. Simulations consider sinusoidal and V-shaped depth path and compare the proposed approach with LOS, PID, and SMC based controllers. Experiments are performed in still water and under simulated Sea-State 1 disturbances to assess steady state accuracy, disturbance recovery, and overall robustness.

KW - Biologically-inspired robots

KW - depth control

KW - marine robotics

KW - robotic fish

UR - https://www.scopus.com/pages/publications/105035295451

U2 - 10.1109/LRA.2026.3681186

DO - 10.1109/LRA.2026.3681186

M3 - Article

AN - SCOPUS:105035295451

SN - 2377-3766

VL - 11

SP - 6504

EP - 6511

JO - IEEE Robotics and Automation Letters

JF - IEEE Robotics and Automation Letters

IS - 5

ER -