Hosseinnajad Alireza, Mohajer Navid
Institute for Intelligent Systems Research and Innovation (IISRI), Deakin University, Australia.
ISA Trans. 2025 Oct;165:98-110. doi: 10.1016/j.isatra.2025.06.025. Epub 2025 Jun 20.
Input saturation is critical in over-actuated systems when multiple degrees of freedom (DOF) with different levels of disturbance rejection are controlled simultaneously by a set of actuators. The current study introduces a novel saturated non-singular terminal sliding mode controller to address input saturation for an over-actuated remotely-operated vehicle (ROV). The proposed controller consists of a tuning algorithm to ensure that the control commands do not violate the time-varying saturation limits of each DOF. In addition, a fixed-time extended-state observer is designed to estimate the vehicle's velocity along with the lumped unknown dynamics of the system. The observer is also employed as a tool to maintain the orientation of the ROV in extreme environmental conditions. The stability analysis shows that all system's states, except for yaw angle, are globally finite-time stable and the yaw angle is globally asymptotically stable. Several sets of simulations are carried out and the results demonstrate the superiority of the proposed controller in terms of positioning accuracy, saturation compensation and transient behaviour under different environmental conditions.
在过驱动系统中，当一组执行器同时控制具有不同抗干扰水平的多个自由度（DOF）时，输入饱和至关重要。当前的研究引入了一种新型饱和非奇异终端滑模控制器，以解决过驱动遥控潜水器（ROV）的输入饱和问题。所提出的控制器包括一种调整算法，以确保控制命令不会违反每个自由度的时变饱和极限。此外，设计了一种固定时间扩展状态观测器，用于估计车辆速度以及系统的集总未知动态。该观测器还被用作在极端环境条件下保持遥控潜水器方向的工具。稳定性分析表明，除偏航角外，所有系统状态均全局有限时间稳定，偏航角全局渐近稳定。进行了几组仿真，结果证明了所提出的控制器在不同环境条件下的定位精度、饱和补偿和瞬态行为方面的优越性。
