Liujiazheng Liu

Mr. Liujiazheng Liu

orcid

Research Focus & Metrics

Academic Career Length

2Years (2025-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
Verified
Journal Article
Open access
PDF file
HXHuang Xinhao
Huang Xinhao
YLYongzheng Li
Yongzheng Li
BWBiwei Wang
Biwei Wang
DLDing Liting
Ding Liting
泽陈泽宇 陈
泽宇 陈
LLLiujiazheng Liu
Liujiazheng Liu
To address the challenge that unmanned surface vehicles (USVs) struggle to effectively balance tracking accuracy, control smoothness, and system energy efficiency under external disturbances, this paper proposes an anti-disturbance path tracking control method integrating quantum-inspired optimization (QIO) and dynamic game theory (GT). The proposed control method consists of a two-layer optimization architecture: the upper layer employs dynamic game theory to optimize the guidance process, modeling the optimization of the look-ahead distance (Ld) and switching radius (R) in the LOS guidance algorithm as a non-cooperative game, and achieves adaptive adjustment to path variations and environmental disturbances by solving for the Nash equilibrium. The lower layer, based on a quantum-inspired optimization algorithm, enhances the control process by employing quantum bit probability amplitude encoding for the PID parameter space and utilizing a quantum rotation gate mechanism for efficient global search, thereby achieving online self-tuning of PID parameters under environmental disturbances. Simulation results indicate that, under sea conditions with external disturbances, the proposed method achieves a superior balance among tracking accuracy, control smoothness, and system energy efficiency compared to the traditional fixed-parameter PID-LOS approach, enhancing the comprehensive anti-disturbance robustness of the USV.

Verified
Journal Article
Open access
PDF file
BWBiwei Wang
Biwei Wang
YLYongzheng Li
Yongzheng Li
LLLiujiazheng Liu
Liujiazheng Liu
Deep reinforcement learning (DRL) enables model-free adaptive control for marine dynamic positioning (DP) under changing disturbances. However, its application remains limited for vessels with strict mechanical constraints, such as the common stern-only dual-azimuth configuration. This paper applies DSAC-T (Distributional Soft Actor-Critic with Three Refinements), a distributional off-policy deep reinforcement learning algorithm, to DP of an 83 m offshore supply vessel under this stern-only configuration. DSAC-T is compared with proximal policy optimization (PPO) and soft actor–critic (SAC) using a shared reward and observation design and an equal simulation budget. All DRL controllers, together with a fixed-gain proportional–derivative (PD) baseline, are evaluated in simulations covering eight wind directions at two wind speeds, together with a calm-water case. DSAC-T achieves the lowest aggregate position-keeping error among the three learning-based methods with lower propulsor-command activity than PPO. We also find that a tighter Gaussian position tolerance in the reward function substantially reduces steady-state position error with a small increase in propulsor-command activity, identifying this tolerance as an influential design parameter for stern-only DP.