基于壁面效应的水下机器人稳定机理与控制方法研究

In recent years, in view of safety problems during long-term operation of ship hulls and dams, more and more new requirements of underwater inspection for early discovery of cracks or other abnormal characteristics rapidly spring up. In these cases, the vehicle must move closely with the structure surface in order to make full use of detection sensors' performance. At this time, the hydrodynamics model and normal control mode of underwater vehicle based on free flow are no longer fully applicable. Feedback control technology based on vision can improve the motion performance of underwater vehicle near the ground, but due to the extremely complex flow with high viscous characteristics in close distance between the vehicle and the ground, the hydrodynamic characteristics becomes critical. Based on comparative study between numerical calculation and model test, especially by means of the micro PIV technology for fine observation of the flow field, this project intends to explore the flow effect and special regulation of hydrodynamics when the vehicle is moving very close to the ground, determine the ideal CFD calculation model by comparison with experimental results. The hydrodynamic influence of different design parameters will be analyzed and the ideal mechanism can be found to be beneficial for the vehicle keeping stable on the ground. Furthermore, the design criteria and control method of the vehicle on the ground will be presented. These will be very important for whole design and stable control of structure inspection vehicles. The research output has theoretical significance and application value for further R&D of underwater vehicle with robust surface moving capability.

近年来，针对船体、大坝等长期运行存在的安全隐患，及早发现其表面异常的水下检测需求迅猛增加。为了发挥检测传感器效能，水下机器人需要紧贴壁面作业，此时基于自由无界流场建立的运动模型及控制模式将不再适用。采用视觉等技术的近壁面反馈控制可改善水下机器人在壁面的运动性能，但由于与壁面距离较近时机器人水动力复杂，运动控制难度大，有效利用其水动力特性的稳定控制成为关键。本项目通过数值计算、模型试验等技术手段相互验证与对比研究，基于Micro-PIV技术对水下机器人在壁面附近的流场进行精细观测，揭示水下机器人在壁面的流场作用效应和水动力特殊变化规律，确定与试验结果吻合的数值计算模型，掌握水下机器人各设计参数对水动力的影响特性，发现有利于水下机器人在壁面运动的水动力稳定机理，提出水下机器人在壁面的构型设计准则与稳定控制方法，这对于研究水下机器人在壁面附近的操纵与控制问题具有重要的理论意义和应用价值。

依托本项目，申请人及项目团队开展了一系列水下机器人构型设计、理论研究及试验研究工作，提出了一种球形海底伏行机器人构型概念并开展了水动力及涡激振动相关研究，揭示了扁平型水下机器人在壁面附近的水动力稳定机理及离底高度与水动力特性的变化规律，与申报书检索文献在磁头分子间的范德华力自稳定特性曲线基本吻合。此外，还搭建了专门用于壁面效应研究的水动力拖曳实验水槽，具备造流和拖车能力，壁面与模型间隙可调，通过三分力天平测量物模多自由度水动力，可获得不同构型和工况下水下机器人在海底壁面附近的水动力。项目发表论文7篇，其中SCI刊源期刊收录5篇、EI刊源收录论文2篇；已申请发明专利19项，授权发明专利7项（国际专利1项）；获得上海市科技进步二等奖1项；培养博士后1人、博士研究生1名、硕士研究生2名。在项目资助的三年时间内，基本按照项目原计划开展研究，研究成果超额完成。