【作者】 张宏伟；

【导师】 王树新；

【作者基本信息】 天津大学 ， 机械电子工程， 2007， 博士

【摘要】 作为有效的水下测量传感器搭载平台,水下自航行器(Autonomous underwater vehicle或AUV)在海洋环境监测领域和海洋资源开发领域的应用前景愈加广阔。但由于携带的能源有限,水下自航行器难以完成长期的海洋测量任务。为了实现长期监测以获得长时序海洋监测数据,本文设计了可着陆水下自航行器。该自航行器具有水下着陆坐底功能,可以执行长时间大航程的水下测量任务。为了实现着陆坐底功能,航行器外形结构采用主体与多个附体相组合方式。与传统的流线型细长体水下自航行器相比,其外形与附体结构更为复杂。为了在设计阶段分析可着陆水下自航行器动力学行为,首先需要建立其动力学模型。针对所开发的可着陆水下自航行器,本文着重探讨具有复杂附体结构的水下自航行器的动力学行为与系统仿真,建立可着陆水下自航行器多体系统动力学模型,并对其着陆运动进行研究。最后,通过约束模型试验和一系列的水域航行试验,完整地实现了预期的设计功能,并且试验结果与仿真结果吻合,验证了本文分析和仿真的正确性。本文的主要研究成果为:1.设计了可着陆水下自航行器原理样机,实现了航行、着陆坐底、测量、上浮通信等功能。该水下自航行器的主要设计特点为:(1)在航行阶段,将测量传感器复用为多普勒计程仪,可有效地节约成本;(2)设计了压载机构和熔断抛载机构,实现了可着陆水下自航行器变浮力功能。2.将多体系统动力学理论方法引入水下自航行器建模过程,建立基于多体系统动力学理论的水下自航行器动力学模型。为了减少计算量,采用基于低序体组的多体系统矢量建模方法推导了可着陆水下自航行器的空间运动方程组。该模型主要优点在于其方便性和精确性。首先,此模型中各体的物理和几何参数可单独估算和修改,避免了具有复杂附体结构的AUV整体水动力参数估算困难的问题,便于AUV的设计和优化,同时具有良好的适用性和通用性;其次,由于该模型详细描述了各体的物理和几何参数,能够获得良好的仿真精度。3.基于水下自航行器多体系统动力学模型,对可着陆水下自航行器纵向运动和横向运动的操纵性进行了分析。通过仿真和分析得出三个结论。(1)可着陆水下自航行器压载水舱位于主体侧下方时航行器具有更高的稳定性;(2)横向运动操纵面布局要服从于纵向运动操纵面布局;(3)操纵面位置和尺寸优化结果表明,可着陆水下自航行器的操纵面最佳位置为距离浮心1.3米处。4.通过研究水下自航行器的着陆运动,提出采用四阶段着陆轨迹实现水下自航行器的着陆任务,并计算出了该轨迹的几何参数。该着陆轨迹充分考虑了可着陆水下自航行器的工作环境的具体要求,比如过载、垂直下降速度、着陆轨迹的连续性和光滑性。仿真和试验表明,与压载后自由下沉的方法相比,采用该着陆轨迹,能够更加可靠和平稳地实现着陆动作。更多还原

【Abstract】 As an effective platform for scientific sensors, autonomous underwater vehicle (AUV) has become an intense area of oceanic research because of their emerging applications in oceanographic survey. However, long-term marine environment measuring is impractical for available AUVs because the energy storage is limited. It is useful to develop the variable buoyancy AUV with the capacity of landing on the seafloor and bottom-sitting for an extended measuring period. In this thesis, a low cost modular AUV with the capacity of landing is developed. Because of more attached bodies, the new AUV developed in the thesis is more complicated than conventional AUVs in shape and construction. Accordingly, the dynamic modeling and the analysis of dynamical behavior of the AUV for landing is more complex than conventional AUVs. The AUV with the capacity of landing can be considered as a multibody system consisting of a base body and several attached bodies. In the thesis, the modeling methods based on multibody system dynamics are applied to the modeling process of the AUV with the capacity of landing. Then the dynamical behaviors of the AUV for landing are simulated and analyzed using multibody system dynamic model. Finally, a series of experiments including captive model experiment and at sea trials are conducted to testify the simulating results. Experimental results show that the simulating results are in good agreement with experimental results.The main contributions of the thesis are summarized as follows:1. The mechanical structures and control systems of the AUV with the capacity of landing are designed to achieve the functions of long-range navigation, underwater landing, bottom-sitting and rising. There are two main features in the system design. One is the convertible design for measuring sensor system. During the process of navigation, the measuring sensors onboard can also be used as DVL (Doppler Velocity Log) and the cost is reduced greatly. The other one is the ballast and releasing mechanism. Tow ballast tanks are designed to change the buoyancy of the vehicle.2. The model of the AUV with complex shape and construction is set up based on the theory of multibody system dynamics. In order to reduce the amount of calculation, the vector modeling method which is deduced from multibody system dynamical theory is applied to work out the motion equations of this kind of AUV. The merit of this model lies in its convenience and precision. With this model, the physical coefficients of each body of the AUV can be evaluated and revised easily without any influence on other coefficients in the process of design and optimization. Because the properties of each body are described in detail, this model can achieve eligible precision for engineering simulation. The multibody system dynamic modeling method presents an adaptive and effective tool for the design and optimization of the AUV.3. Based on the above dynamic model, the thesis analyses and optimizes the maneuverability of lateral movement and longitudinal movement of the AUV with the capacity of landing. Consequently, the following conclusions can be made. Firstly, the position of rudder should conform to the position of elevator. Secondly, the position of the ballast tanks fixed on the AUV should be lower than the position of the main cabin to attain the motion stability. Thirdly, the optimized result of the elevator position is 1.3 meters from buoyancy center.4. As for the landing movement of the AUV, four-stage landing trajectory is presented according to the physical requirements such as overload, vertical descent rate,continuity and smoothness. Then, the geometric parameters of the landing trajectory are work out. Compared to the landing method of free-fall in water, the proposed landing method is more reliable according to the simulation results and sea trial results.更多还原