This article compares output feedback control strategies for an underwater thruster. There are a variety of dynamic models for thrusters, some of which can account for fluid-velocity dynamics and others that account for propeller angular velocity dynamics. Here, the contributions of both fluid and propeller velocities are modeled with three levels of complexity: simplified, hydrodynamic linear, and hydrodynamic quadratic models. Multiple methods are presented to estimate axial flow velocity, which is handled as an unmeasured state. The performance of controllers based on these models and estimators is compared for a single thruster as well as for an underwater vehicle with a nonorthogonal multithruster layout. All models, controllers, and estimators are experimentally evaluated in closed-loop experiments using a load cell to measure the tracking performance of an individual thruster. Full vehicle simulations using experimentally characterized models provide additional insights into the control and estimation strategies and their relative merits.

中文翻译：

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基于模型的遥控水下航行器推进器控制的跟踪性能

本文比较了水下推进器的输出反馈控制策略。推进器有多种动力学模型，其中一些可以解释流体速度动力学，而另一些可以解释螺旋桨角速度动力学。在这里，流体和螺旋桨速度的贡献以三个复杂级别进行建模：简化模型、流体动力学线性模型和流体动力学二次模型。提出了多种方法来估计轴向流速，将其作为未测量状态处理。比较基于这些模型和估计器的控制器的性能，用于单个推进器以及具有非正交多推进器布局的水下航行器。所有型号、控制器、和估计器在闭环实验中进行实验评估，使用称重传感器来测量单个推进器的跟踪性能。使用实验表征模型的整车模拟提供了对控制和估计策略及其相对优点的额外见解。