水下柔索悬吊并联运动平台的设计理论与控制方法研究

As a class of marine intelligent instruments, existing underwater robots such as ROV and AUV all suffer from small load capacity, limited functionality and vulnerability to environmental disturbances. This project is aiming to fuse parallel mechanisms and underwater robotics and proposes a novel concept of multi-dof underwater cable-suspended parallel platform. This mechanism is composed of a surface vessel, cables and an underwater platform. By changing the lengths of the actuated cables, the pose of the underwater platform is controllable. This novel configuration renders the platform great merits such as large workspace, large load capacity and resistance to disturbances. For the three planar and two spatial types of the mechanism, kinematics, dynamics, trajectory planning and robust control will be carried out. Utilizing a series of methods such as Newton-Euler, Lagrange and Finite Element, the rigid-flexible coupled multi-body dynamics model under marine environment can be developed. Based on the synthesis of sliding mode, H-infinity control and so on, robust motion controllers will be designed to ensure the stability and tracking accuracy of the underwater platform in face of a moving vessel. Finally, a systematic methodology will be established to design and control the underwater cable-suspended parallel platform. This project will contribute to the advancing of marine intelligent instruments in China.

作为海洋智能装备的一类，现有的水下机器人ROV与AUV等都存在负载能力小，作业能力有限，运动轨迹易受环境干扰等缺点。本项目将并联机构学与水下机器人学融合，提出多自由度水下柔索悬吊并联运动平台的概念。该机构由水面船体，驱动柔索与水下平台三部分组成，通过船体上的缆车改变柔索长度来控制水下平台的位姿，具有工作空间大，负载能力强，抗环境扰动能力强等优点。围绕该机构的三种平面基本构型与两种空间基本构型，本项目拟开展运动学，动力学，轨迹规划与鲁棒控制等研究。采用牛顿-欧拉法、拉格朗日法、有限元法相结合的方法建立该系统在海洋环境下包含多种环境扰动力在内的刚柔体耦合动力学模型。综合滑模控制、H∞控制等多种鲁棒控制算法的优点设计控制器，实现水下平台在水面船体浮动或巡航时的运动稳定性以及对扰动的抵抗能力。最终形成一套设计与控制水下柔索悬吊并联平台的系统性理论方法，对我国海洋智能装备事业的发展具有积极意义。

本项目提出了一类新颖水下柔索悬吊并联机构。该类机构包含了多种多自由度运动构型，是悬索并联机构与水下机器人的有机融合。本项目主要研究了该类机构的建模与控制。主要内容包括：率先提出了一种空间四自由度与一种空间五自由度悬索并联机构，完善了该类机构的构型家族；建立了悬索质量不可忽略时基于悬链线方程的二、三自由度构型运动静力学模型，并求解了空间正反向解；分别针对动力学模型准确与不确定两种情况，设计了二、三、六自由度构型的计算力矩控制器以及鲁棒滑模控制器；应用区间分析获得了满足张力约束的控制器参数可靠空间；对多种悬索并联机构拾放轨迹进行了综合性比较研究，获得了能耗最优的轨迹参数。上述研究为该类机构在水下环境中的应用提供了理论基础。