输入饱和约束下AUV全驱动/欠驱动位形切换跟踪控制

Autonomous Underwater Vehicle (AUV) is the important tool for ocean exploration and exploitation. Path tracking control is one of the key techniques to guarantee the successful implementation of various underwater missions. However, the control design for AUV is far more challenging due to the varied actuation configurations caused by the changed actuation efficiency of the rudders and thrusters. The varied surge velocity results in the switching behaviors between fully actuated and underactuated configurations. Furthermore, the actuators also suffer from the saturation constraints, which easily rendering the chattering of the vehicle and even resulting in the unstable effects. Smooth transition rather than hard switching between the underactuated and fully actuated configurations is preferred to avoid the quick saturation and subsequent instability. In this project, a synthesized control design is proposed to account for the problems of actuator saturations and switching configurations embedded in path tracking, based on a smooth transition method and nonlinear smooth adaptive approximation design. All the control schemes are developed under the framework of multi-Lyapunov synthesis approach, such that the robustness and the stability of the whole closed-loop path tracking control system is rigorous.

水下航行器是海洋资源探测与开发的重要工具，航迹跟踪控制是其关键技术之一。航行器在全航速域内从低速到高速航行时舵和辅推的效率会发生变化，从而导致航行器在全驱动位形和欠驱动位形之间切换，若直接采用关闭低效驱动器而启用高效驱动器的“冷切换”方式，会导致控制指令“突变”，航行器会出现“振荡”运动；另一方面，航行器还受到螺旋桨转速大小、操舵角范围等驱动器物理限制所引起的输入饱和约束，驱动器饱和会降低系统的控制性能，且会加剧驱动位形切换时的“膨胀饱和”，导致航行器控制系统“失稳”。本项目拟深入分析航行器在较大航速调节范围内工作时的驱动位形变化特点，基于全航速域构造全驱动/欠驱动两种位形之间的平滑“热切换”，结合非线性饱和光滑自适应逼近法和多重Lyapunov函数原理，设计输入饱和、驱动位型切换、航迹跟踪控制的一体化框架，实现输入饱和约束下航行器驱动位形平滑切换，保证航行器控制系统饱和切换跟踪稳定性。

自主水下航行器（AUV：Autonomous Underwater Vehicle）是海洋资源探测与开发的重要工具，高效自主运动控制是其核心技术之一。AUV在从低速到高速的全航速域内航行时舵面和辅推效率会发生变化，导致AUV在全驱动和欠驱动位形之间切换，位形冷切换易导致控制指令突变并出现跟踪振荡；AUV受螺旋桨转速、操舵角范围等驱动系统物理限制所引起的输入饱和约束会降低系统的控制性能，且会加剧位形切换时的膨胀饱和，导致系统失稳。.针对AUV系统不确定性、输入饱和及位形切换等多重因素约束下的路径跟踪控制问题，本项目开展的研究内容及取得的重要结果如下：.1. 全驱动/欠驱动模态下AUV动力学建模及操纵性能评估。在传统AUV动力学建模基础上，完善了操纵面、主推及辅推等执行器非线性建模，考虑了输入饱和及动力学延滞双重特性，完成了全航速域内操纵性能评估并设计了全驱动/欠驱动位形的光滑逻辑切换流。.2. 基于模糊自适应逼近补偿的欠驱动AUV有界跟踪控制。提出自适应模糊逼近和误差估计方法解决系统模型不确定性和反步复杂计算问题，引入抗饱和自适应模糊补偿器，消除欠驱动跟踪时输入饱和诱发的潜在控制失稳。 .3. AUV全/欠驱动位形切换下光滑有界推力分配控制。基于执行器逻辑切换流和饱和俯仰力矩设计了光滑有界的推力分配流，融合垂向推力被动控制，设计阈值分析和滑动分配策略，确保水平舵和艏艉垂推控制的唯一性与有界性，使AUV控制稳定性独立于驱动单元。