Abstract
Underwater robots play a crucial role in exploring aquatic environments. The ability to flexibly adjust their attitudes is essential for underwater robots to effectively accomplish tasks in confined space. However, the highly coupled six degrees of freedom dynamics resulting from attitude changes and the complex turbulence within limited spatial areas present significant challenges. To address the problem of attitude control of underwater robots, this letter investigates large-range pitch angle tracking during station holding as well as simultaneous roll and yaw angle control to enable versatile attitude adjustments. Based on dynamic modeling, this letter proposes an adaptive integral sliding mode controller (AISMC) that integrates an integral module into traditional sliding mode control (SMC) and adaptively adjusts the switching gain for improved tracking accuracy, reduced chattering, and enhanced robustness. The stability of the closed-loop control system is established through Lyapunov analysis. Extensive experiments and comparison studies are conducted using a commercial remotely operated vehicle (ROV), the results of which demonstrate that AISMC achieves satisfactory performance in attitude tracking control in confined space with unknown disturbances, significantly outperforming both PID and SMC.
Abstract (translated)
水下机器人对探索水下环境具有关键作用。实现灵活的态度调整对于水下机器人有效执行任务在受限空间内是至关重要的。然而，由态度变化产生的高度耦合的六自由度动力学以及有限空间内的复杂涡流带来了重大挑战。为解决水下机器人的姿态控制问题，本文研究了在站控期间的大范围俯仰角跟踪以及同时控制横滚和偏航角以实现多功能的姿态调整。基于动态建模，本文提出了一种自适应积分滑动模式控制器（AISMC），将积分模块融入传统的滑动模式控制（SMC），并自适应地调整切换增益以提高跟踪精度、减少扰动和增强鲁棒性。通过Lyapunov分析建立了闭环控制系统的稳定性。使用商用遥控器（ROV）进行广泛的实验和比较研究。结果表明，AISMC在未知扰动下，在受限空间内实现令人满意的姿态跟踪控制，显著优于PID和SMC。
URL
https://arxiv.org/abs/2405.00269
