The position accuracy of the polishing tool affects the surface quality of the polished aspheric surface. The contact deformation among the polishing tool, abrasives, and aspheric part can cause a displacement, which, in turn, will cause a position error of the polishing tool, which will lead to a significant change in the polishing force. In order to resolve this error, this paper proposed a method of normal displacement compensation for a computer numerical controlled (CNC) polishing system by controlling the polishing force. Firstly, the coupling principle between the polishing force and the position of the polishing tool is expounded, and the relationship between normal displacement and deformation is analyzed. Based on Hertz’s theory, a model of normal displacement is established. Then, on the basis of the decoupled polishing system developed, a normal displacement compensation method was proposed. Finally, a group of comparative experiments was carried out to verify the effectiveness of the proposed method. Compared with no displacement compensation, when the part was polished with the normal displacement compensation method, the value of roughness decreased from 0.4 µm to 0.21 µm, and the unevenness coefficient of surface roughness decreased from 112.5% to 19%. The experimental results show that the polishing quality is improved greatly, and the aspheric surfaces can be polished more uniformly with the method proposed in this paper.

船型网箱是一种新型抗风浪深水网箱,其采用船形结构以及单点系泊方式,合理的锚泊系统设计是保证船型网箱安全可靠的关键.依据Stokes二阶波浪理论和Morison方法,采用数值方法分析了锚泊系统串联浮筒对船型网箱水动力特性的影响以及不同波况作用下浮筒位置、大小对锚绳力的影响,并进行了物理模型实验验证.结果表明,船型网箱最大锚绳力随着波高的增大而增大,随周期变化不明显;串联浮筒增加了浮架纵向位移,使得浮架相对水质点速度减小,从而减小了浮架所受最大波流力以及锚绳力;最大锚绳力随着浮筒直径增加先减小后增大,随着浮筒位置远离浮架连接点而减小.

Savonius桨叶是一种典型的垂直轴阻力型桨叶,在风力发电中广泛应用.这种桨叶具有在多风向作用下单向转动的特性.利用该特性,将其应用于捕获水质点运动方向发生周期性或非周期性改变的波浪能的相关研究.采用Fluent数值仿真软件并基于UDF二次开发技术建立桨叶三维数值模型,分析叶片重叠率、相对入水深度和开口率等参数对桨叶动转矩和功率等水动力特性的影响,搭建实验平台,开展物理模型对照试验.研究结果表明:叶片重叠率有助于减小S型桨叶负转矩;当桨叶在水面上高度与波幅相等时,其功率系数达到最大;在叶片上增加弹片阀开口,可以增大桨叶动转矩系数,当开口面积达到一半时,动转矩系数比未开口桨叶提高28.3％.

针对海工作业平台、海洋养殖网箱等海洋装备的安全防护问题,提出了一种带空气透平的后弯管浮式防波堤,该空气透平既可将作用在防波堤上的波浪能转化成机械能并用于发电,还可显著减小防波堤的锚链力.在介绍了防波堤原理和结构特点的基础上,设计了物理实验模型,并在实验室造波池内进行了模型试验,研究了波浪周期、波高、吃水深度与弯管数量等因素对后弯管浮式防波堤透射系数和锚链力的影响规律.研究结果表明,波浪周期越短,波高越低,防波堤的透射系数越小,锚链力越小,其消波性能优于传统的浮式防波堤.

Aiming at accurate counting of a number or batch of fish in process of feeding,transporting and selling, a fish counting algorithm based on machine vision tracking is proposed. According to a certain time interval, dynamic track and shoot fish images,use image processing technology to extract area of each image block as its eigenvalue. According to the size of area,the image block is divided into normal image and abnormal image,and the normal image and abnormal image are respectively analyzed and processed. Correlated algorithm model between the image eigenvalue and the number of fish is established. The optimal model parameters are obtained by regression of multiple sets of image data captured by dynamic tracking,determine the estimation function and applied to the count summation. Experimental results show that this method of fry counting based on dynamic visual tracking and regression analysis can effectively distinguish the adhesion problems during fry counting and improve precision of fry counting.

The large-scale floating rope round net aquaculture facility is a new equipment for aquaculture offshore,and the key to improve round net facility's ability to resist the wind and waves is the force analysis.Based on the sine wave theory and Morison method,the characters of vertical force on the local round net are analyzed.Based on the equivalent netting panel method and lumped mass method,the finite element model is established to analyze simplified netting panel.The calculating conclusion shows numerical model result well,and the average error ratio is less than 19％.Vertical force on the round net facility increases with the increase of wave height,and the buoyancy and vertical force on floater are main parts of vertical force on the round net.Wind and wave resistant performance test of the round net facility is carried on,and the test results show that the structure design of round net facility is reasonable and the vertical force analysis of round net facility in this paper has a certain reference value to design sole laying system and the mooring system.

In recent years, with the development of fish cage aquaculture technology, the traditional way of bait casting cannot meet the growing demands any more. As fishes feed with certain regularities, it is important to acquire the feeding conditions of the fishes. Through analyzing the images of fishes feed by the way of image processing, the feature of the shape and the area of fishes is extracted. The gross of feeding is setup based on the shape, which reflects the weight of fish. The feeding amount is changed with the variation of the image of fish in feeding at real time. The cast program according the extracted feature and the cage aquaculture experiment is designed to verify the feeding effect. Experimental result shows that the smart cast can setup the bait according to the growing requirement of the fishes. The bait utilization will be increased, and water pollution will be reduced, and the fish quality can be improved as well through the smart cast system.

基于叶素动量理论和伯努利原理建立桨叶动力学模型,从能量捕获效率最大化原则出发,采用非线性优化方法求解得到桨叶外形参数,并制作出桨叶进行实验测试.结果表明,优化后的桨叶在设计流速附近运行时能获得更大的功率,并更接近理论预测值,可验证该动力学模型的正确性和有效性.

Wave maker is the key basic equipment for wave simulation.The development of experimental tanks is briefly introduced,and then the current status of experimental tanks and the wave generation technology are discussed.Considering the requirement of engineering practices,the problems of wave frequency and amplitude maintenance,as well as amplitude of precise control with the existent wave generators are analyzed,and a novel hydraulic drive technology for wave generation is proposed.This wave generation technology can simulate high power water waves better.The key technology is the control of the wave frequency and amplitude that is realized through the rotation of the valve spool driven by a motor,and the moving direction change of the hydraulic cylinder led by the high frequency alternation of the fluid flow.To better reproduce the high power sea waves and simulate realistically the interaction of structures with waves the investigation of high power wave generation technology based on the control of electro-hydraulic rotary valve would be an important research direction in the field of wave generation experiment.

针对球阀阀芯自动装配过程中存在的装配柔性低、时常无法精确定位问题,基于机器视觉技术,构建出一套在线机器视觉系统.采用NI Vision Assistant模块对系统及图像进行快速、准确的标定,并在其中对部件图像进行预处理、模式匹配以及边缘检测等修正处理.在LabVIEW中调用Vision Assistant节点得出部件的位置和角度信息,经以太网与下位机通信,动态改变机器人装配动作,并在搭建的硬件实验台上进行在线验证.实验表明,该系统所采用的方法可行、稳定,能够满足阀芯装配快速、准确的要求,达到了预期的效果.

At present, in an aquaculture environment, bait casting process of feeding machine mainly uses total time. Such feeding does not consider fish feeding regularity so it wastes bail and causes environmental pollution. High efficiency and intelligent bait casting machine system study thus becomes urgent. An effective way is to set the feeding amount through observing fish aggregation. An intelligent bait casting method based on machine vision technology is proposed in this paper. Through image processing, the geometric area of the fish within the window of the camera and the ratio of the fish area to the widow area were extracted from the pictures, and were taken as characteristic parameters of the pictures. These characteristic parameters can reflect well the crowding level of the fish during the feeding process, and the variation curves of the parameters with time can represent the feeding regularity of the fish. It was also found that the parameter variation curves were similar for different fish. Based on the parameter variation curves, new bait casting scheme was designed. The advantage of using this method is it makes bait casting scientific and reasonable, not only saving feeding cost but also reducing environment pollution.

提出一种低流速下总体发电量高的潮流能捕获系统,以实现深水网箱的能量自给.建立一个潮流半月周期内叶轮的总体发电量数学模型,对S型和H型2种不同叶轮的性能进行分析比较,得出S型叶轮在潮流流速较低时能自启动且总发电量较高;并对该叶轮结构参数进行优化,提高其在低流速时的功率系数.试验结果表明,该种潮流能发电装置能充分利用低流速潮流能为深水网箱供给能量,具有良好的使用效益.

针对水平轴潮流能发电桨叶专用翼型的设计问题,对翼型的流场、翼型捕获能量的机理、二维翼型的升阻力系数和x方向切应力系数等方面进行了研究,对航空翼型与风力发电机专用翼型在捕获冲击能量上的不足之处进行了探讨,提出了一种水平轴潮流能发电桨叶专用翼型的设计方法,该翼型能综合利用压差升力与冲击作用力,从而提高潮流能的整体捕获效率.基于叶素动量理论并借助Matlab迭代,求解出了桨叶21个截面的弦长与扭角,利用Cincinnati加工中心制作了桨叶并在水槽实验平台上进行了试验,观察并记录发电数据.试验结果表明,通过增加翼型尾部弯度能有效提高水平轴潮流能发电桨叶的自启动性能和能量捕获效率,验证了该设计方法的正确性与有效性.

基于视觉的图像处理技术逐渐成熟,将图像处理应用在工件检测中也被广泛认同;利用图像检测螺纹的技术和装置也不断被改进和完善;针对螺纹图像检测中连续性较低、精度不高的问题,设计了一种连续自动螺纹检测系统;在圆盘上均匀分配4个工位,由电机和分割器带动,实现螺纹检测过程的放置提取、工件判断、表面除杂以及图像采集4个过程;高精度工业相机获取的螺纹图像,应用LabVIEW中Vision assistant模块,实现图像的几何畸变矫正、边缘检测、目标分割、图像标定、参数计算和检测;经过实验证明,该系统实现了螺纹检测的自动化,并且提高了螺纹检测的精度。

本文提出了以船形大浮子和陀螺形小浮子组合的双浮子波浪能发电试验平台,并针对陀螺形浮子展开了仿真研究.通过改变陀螺浮子的锥顶半径尺寸,建立了陀螺形浮子在波浪水平和竖直冲击作用下的受力和变形模型,分析了其对波浪的适应特性、功率特性以及效率特性,并对影响浮子受力和变形的关键参量进行了优化分析.仿真结果表明,陀螺形浮子作为漂浮式试验平台的波浪能捕获装置是合理的.

In recent years ,with the development of marine aquaculture technology ,the traditional way and equipment of bait casting can not meet the growing demands any more .As fishes are fed with certain regularities ,it is important to acquire the feeding conditions of the fishes ,and on the basis ,to control the bait casting equipment in real time .Applying machine vision technology and embedded system to collect and process the images about fish feeding ,the eigenvalues of the fish feeding condition ,such as the position ,number ,and degree of hungry of the fishes ,could be ob‐tained in real time .A smart bait casting machine was developed .The kinematic ,dynamic ,and con‐trol models of the baiting and throwing mechanisms of the machine were established .The smart control of the bait casting process was achieved based on the results of real time image process and the model of the machine .Experimental result showed that the smart machine developed based on machine vision and real time decision technology could cast the bait according to the growing requirement of the fishes ,and therefore ,the bait utilization could be increased ,the bait waste and water pollution reduced ,the aquatic cultivation cost saved ,and the fish quality im‐proved as w ell .

When a soft polishing tool is compressed on a stiff workpiece of curved surface, the contact area is a piece of the curved surface. In the process of aspheric surface polishing, the machining speed is always provided by the rotational speed of the spindle of a computer numerical control lathe. Yet, the polishing tool is usually made rotating to remove cutting scraps and broken abrasives from the contact area. The rotational speed of the polishing tool would change the distribution state of the relative speed in the whole contact area, and it would definitely change the volume of material removal in the surface of the workpiece. This article studies how the rotational speed of the polishing tool changes the distribution state of the relative speed in the whole contact area and material removal in the volume of the surface of the workpiece. The computing results show that the volume of material removal increases with the increase in both the rotational speed of polishing disk and the rotational speed of lathe spindle, but the polishing quality is totally not in this case.

针对目前各种波浪能发电装置中存在的可靠性低、寿命短、建造维护难等问题,结合我国大部分海域低能流密度的现实,介绍一种以双体船为载体、以陀螺浮子捕获波能的振荡浮子式发电装置.以Workbench为平台,首先完成几何建模及网格划分,然后分别在FLUENT和ANSYS中完成流体分析与结构分析,得出了不同底圆半径的陀螺浮子在水流水平和竖直冲击下的受力和变形,以此为依据判断其对波浪的适应性、功率特性以及效率特性.通过数值模拟研究,遴选影响浮子受力和变形的关键参量,为该类浮子的实用化设计提供依据.仿真结果表明,选择陀螺形浮子作为试验平台波浪能捕获装置是非常合理的.

针对非球面研抛过程中的力/位耦合问题,本文通过磁流变液力矩伺服控制装置进行力的控制,由数控车床完成位置及速度等工艺参数的控制,实现了力/位解耦,从而提高了研抛的精度.根据Preston研抛控制机理,建立了力控制的实现模型,在确定了研抛过程的工艺参数后,进行了研抛实验研究.通过计算椭球面研抛过程的驻留时间,进而确定了不同位置的时间与研抛力的对应关系,通过控制磁流变液力矩伺服装置的电流输出得到相应的研抛控制力,使其与数控机床给定的进给速度及位置进行匹配.实验结果表明:通过驻留时间进行力控制的方法可以实现高效率研抛加工中力的控制.