【作者】 徐海军；

【导师】 潘存云；

【作者基本信息】 国防科学技术大学 ， 机械工程， 2010， 博士

【摘要】 仿生推进技术是当前水下机器人研究热点之一，其中的中央鳍／对鳍(Medianand／or-Pair Fin，MPF)波动仿生推进方式更是由于其独特的仿生结构和突出的推进性能而倍受科研人员关注。然而受波动推进机理研究和科技发展水平制约，已有波动鳍仿生推进器大多采用刚性运动链结构形式，其综合推进效果离人们期望的高效柔性仿生推进目标还有一定差距，更难与自然界鱼类游动相媲美，因此研制高效柔性波动鳍仿生推进器具有重要意义。论文研究来源于国防基础科研项目，针对现有各种驱动方式仿生推进器存在的不足，结合流体传动的柔性体系结构和传动特性，设计了一种采用液压驱动的波动鳍仿生推进器系统，并围绕其液压传动原理和仿生结构、运动规律和动力特性、流体动力行为和推进性能等展开了理论分析与试验研究，主要内容如下：1．提出了液压驱动的波动鳍仿生推进器系统设计方案，设计了波动鳍仿生推进器的液压驱动系统，以及旋转式流体分配阀、带复位弹簧的仿生摆动关节等关键零部件和整体仿生结构。由于液压系统独特的作用规律和传动特性，使得各个仿生摆动关节不仅运动彼此保持独立，而且省去了传统驱动系统中用于将电机连续旋转运动转换为仿生关节摆动的运动变换机构。所设计的液压驱动的波动鳍仿生推进器，不仅结构上能够根据水下仿生机器人自身形状合理布置，而且在运动上能够通过改变波动幅度实现全基线上仿生波形柔性启动、停止和运动形态自恢复，并能够被动地适应外界流体负载变化，使仿生结构始终保持在最佳承载状态。仿生鳍面在液压系统不工作时自动回复至平衡位置，以减小形体阻力。2．完成了旋转式流体分配阀和带复位弹簧的仿生摆动关节系统建模，分析了阀泵联控液压系统的作用规律。建立了旋转式流体分配阀各阀口编号与编组规则，以及各阀口统一流量方程，分析了流量周期性、有序变化规律，并对由阀芯转动控制多个阀口周期性换向而产生的液动力矩进行了建模，分析了阀芯的谐振特性。建立了带复位弹簧的仿生摆动关节传递函数和运动模型，并对其平衡位置特性及动态角位置刚度特性等进行了研究。根据搭建的阀泵联控液压系统模型，研究了变量泵和旋转式流体分配阀联合作用下，多摆杆拟合波形在初始平衡位置状态与稳定波动状态间的演变规律。3．建立了液压仿生波动鳍运动学模型和动力学模型。采用直纹曲面方程建立了液压系统作用下的仿生鳍面运动学模型，对仿生波形可展性进行了研究，并分析了结构参数对仿生运动形态的影响。采用拉格朗日方程建立了液压仿生波动鳍多摆杆系统的动力学模型，并构建了相应的计算多体动力学模型，研究了在不同弹簧刚度、不同阻尼以及不同变化规律液压驱动力作用下多摆杆系统的动力学行为，包括仿生波形的平衡位形稳定性、仿生波形在启动与停止过程中的变化规律等。结果表明，多摆杆系统在周期性液压驱动力作用下能够快速地实现有效的仿生波形，其启动与停止过程具有自稳性和柔性。4．建立了仿生鳍面波动时的流体动力和动力矩理论计算模型，根据仿生鳍面运动学模型设计了鳍面网格变化规律，采用计算流体动力学(Computational FluidDynamics，CFD)方法分析了流体动力和流场压力变化规律。结果表明，流体动力和动力矩的变化具有明显的周期性，并存在倍频效应，即推进力、升力和俯仰力矩的变化频率是仿生波动频率的两倍，侧向力、横滚力矩和偏航力矩的周期均值约为零。阐述了液压驱动的波动鳍仿生推进器在流体环境中的负载自适应特性，分析了其内涵和作用原理。5．研制了液压驱动的波动鳍仿生推进器原理样机试验系统，利用原理样机对液压驱动系统的工作原理与作用规律进行了研究。开展了旋转分配阀定时、有序地控制液压流体的设计原理验证试验；通过试验对比了有／无复位弹簧两种结构下仿生摆动关节的运动规律，并研究了弹簧刚度大小和液压系统参数的变化对仿生摆动关节运动特性的影响；测试了原理样机的柔性启动特性和负载自适应特性。最后开展了原理样机的水下推进试验。结果表明，仿生鳍面在液压系统驱动下能够形成有效波形并推动原理样机运动，通过改变旋转分配阀转速和转向可调整仿生波动速度的大小和方向。试验结果验证了设计原理的可行性，检验了理论分析的结论，达到了预期研究目的。更多还原

【Abstract】 Underwater bionic propulsion technology has gained much attention around the world, especially the bionic undulating propulsion in MPF(Median and/or Pair Fin) mode with special structure and outstanding propelling characteristics. However, as is restricted by the development of undulation mechanism and engineering technology, most of the bionic undulating propellers (BUPs) are designed and implemented with rigid transmission chain. Such a rigid chain is consisted of rotational motors and motion-changing frameworks, which make the general propulsion performance far away from that expected, say nothing of comparing to the swimming ability of nature fish. Obviously, research on BUP with flexible structure and propelling character is of significance in near future practical applications.This work is supported by the Basic Science Foundation of National Defense. After a detailed consult on the conventional BUPs. and considering about the special structure and unique acting rules of hydraulic transmission, a newly-designed BUP driven by Valve-Pump controlled hydraulic system (HBUP) is presented with a novel structure and flexible power driven-chain in this dissertation. Then some research has been carried out on the mechanism and structure design, kinematics and dynamics, together with hydrodynamic characters. The main work can be summarized as follows:1. A novel scheme of BUP’s hydraulic driven structure and driven-chain is proposed in this dissertation, and the hydraulic driven system in HBUP is designed, including the structures of the rotational direction valve, hydraulic swinging unit, and the HBUP’s comprehensive structure. The peculiarity of fluid transmission makes each hydraulic swinging unit swings independently, so that rigid transmission shafts are no longer necessary. The HBUP’s structure could fit underwater robots" shape and produce bionic undulation with a changeable amplitude on the structure during starting and stopping processes. Meanwhile, the HBUP system could carry complex fluid load passively and keep the whole structure with a best load capacity. While the hydraulic system doesn’t work, the bionic undulating fin will recover to the original balance state automatically, so as to reduce the fluid resistance during cruising.2. The uniform flux equation of the rotational direction valve’s ports and transfer function of the hydraulic swinging unit are presented and developed. Within these equations, the acting rules and characters of the hydraulic system in HUBT are studied. Referring to the analyzing method of common hydraulic direction valve, this uniform equation of the rotational direction valve’s ports is built up to analyze the flux between different ports Then effects of hydrodynamic force and torque caused by the shaft rotation is also considered. The hydraulic swinging unit system performance, in terms of stability, balance and position holding ability, are respectively studied with the established transfer function, according to the analyzing means of valve-controlled symmetrical cylinder. Simulations of the hydraulic system model show that it could drive the HBUP consisted of several hydraulic swinging units to produce a bionic motion from a flat shape to an undulating shape and vice versa.3. The ruled-surface kinematics model of the HUBP is brought forward, so is the multi-rigid-body dynamic model. Then the extensibility of the niled-surface, and effects of structure parameters to bionic undulating fins are theoretically analyzed. The Lagrange equation is introduced to build multi-rigid-body dynamic model of swinging poles in HBUP. and then a prototype model of the multi-rigid-body system in HBUP is developed as well. With these models, effects of different spring rigidities, different damp coefficients and different hydraulic forces on the multi-rigid-body system are explored, one by one. The results reveal that the restoration springs are of importance since the balance position of the HBUP is ensured stable, and the swinging poles could be driven into undulation effectively and rapidly. The bionic undulation in starting and stopping processes exhibits flexibility and auto-stability characters.4. The computational hydrodynamic model of the HBUP is proposed and developed. In detail, the ruled-surface kinematics equation is used to design the changing mle of the dynamic mesh in computational fluid dynamics (CFD) method, which is used to compute the hydrodynamic force and torque, as well as the fluid pressure distributing characters. The results show that the hydrodynamic force and torque change periodically in evidence, and some of them present doubled-frequency character. The doubled-frequency character can be summarized as follows: the changing frequencies of the propelling force, lifting force and pitching torque are twice of the bionic undulation frequency respecitvely. the values of yawing force, rolling torque and yawing torque are nearly zero in average. At last, the load adaptability of the HBUP is proposed, and hereafter, the reasons and effects are studied as well.5. The testbed of HBUP is constructed, and some function-verifying experiments are carried out as well as propelling tests. With the testbed, the flux-distributing function of the rotational direction valve is verifid, and the swinging character of hydraulic swinging unit is also tested and compared, with spring and no spring structure, under different hydraulic system parameters. Then the flexible starting character and load adaptability are verified. The propelling tests of the HUBT are also brought out under different hydraulic system parameters. The results show that bionic fin of HBUP could form a valid undulation shape to produce propelling force, so as to make the prototype moving, its propelling force and direction could be easily controlled by adjusting the rotation velocity and direction of the shaft in the rotational direction valve. The experiments have verified the conclusions and meet the expected objectives.更多还原