水下仿生机器鱼的研究进展III——水动力学实验研究

作为仿生推进技术研究的一个主要环节，仿生机器鱼平台的实验测试研究具有重要的 意义．本文建立了一套比较系统完整的机器鱼水动力学定性观察，定量测量的实验环境，并 进行了速度功率参数影响测定实验、鱼体流动显示实验和鱼体运动阻力测定实验．     

基于CFD的仿鲹科机器鱼动力学建模与运动控制

仿生机器鱼的运动控制是仿生机器鱼推广应用的基础;然而,仿鲹科机器鱼的推进一般采用鱼体波数据,很少采用真实鱼类游动数据;为了深入探究仿鲹科机器鱼运动控制方法,采用了计算流体力学方法,通过标定流体介质、来流速度、鱼体几何形状等措施,利用Fluent软件进行了建模,然后针对鱼体波数据和真实金枪鱼游动采样数据两种不同推进数据对仿生机器鱼进行了仿真和实验;结果表明对于多关节仿生机器鱼推进方面,真实金枪鱼游动采样数据相较于常见的鱼体波产生的推进数据,在躯干进行大幅值摆动的情况下效果更好;这一仿真和实验对比为仿鲹科机器鱼的高效运动控制提供了一种新思路。     

水下仿生机器鱼的研究进展Ⅳ——多仿生机器鱼协调控制研究

本文探讨了多仿生机器鱼群体游动协调的问题,这是仿生机器鱼技术研究的一个新的方向,目前尚无人涉足.首先研制了一套具有高效、高机动性的微小型多机器鱼平台,提出了基于AGENT的网格算法进行多机器鱼的定位和协调控制,利用该实验平台,进行了多机器鱼对抗和多机器鱼协调过孔的实验研究.     

基于仿生学和北斗技术的水质检测机器鱼研究与设计

针对常规水质检测方法,存在检测效率低、范围小的问题,提出以研制仿生机器鱼为平台的低成本水质检测方案。以鱼体结合尾鳍的BCF推进模式作为研究对象,分析鱼体波包络曲线的游动机理。运动学参数化计算研究BCF鱼体推进运动姿态,结合CFD流体分析优化机器鱼系统,搭建基于北斗系统BDS的导航定位和水质样本采集系统,并通过实验样机验证了机器鱼检测水质的可行性。     

具有嵌入式视觉的仿生机器鱼头部的平稳性控制

具有嵌入式视觉的仿生机器鱼的摄像头往往安装在头部,为了获取稳定的图像数据,研究了游动过程中头部的平稳性控制问题.首先,基于牛顿-欧拉方法对仿生机器鱼的水动力学进行建模.然后,基于动力学模型,比较了两种鱼体波模型下的机器鱼头部摆动情况.进一步地采用遗传算法对输入到运动关节的参数进行优化,实现机器鱼头部的最小摆动.最后,在自主设计的具有嵌入式视觉的仿生机器鱼上进行了实验.结果表明,在平稳性控制后,头部的摆动幅度明显减小,采集到的图像的稳定性与连续性有较大改进,但游动速度有所降低.该方法为基于嵌入式视觉的运动控制与任务执行提供了有效保障.     

仿生机器鱼运动学模型优化与实验

以仿生学为基础的机器鱼是一种新型水下机器人,具有高速、高效、节能等方面优势。为进一步探索仿生机器鱼的运动机理,指出了当前仿生机器鱼运动学模型存在的不足,即未考虑因制造、鱼体结构的影响,而产生的头部左右摆动。故在考虑仿生机器鱼头部摆动的情况下,构建头部摆动方程,引入摆动偏移量,修正其运动学模型。利用MATLAB对模型进行优化,分析结果表明修正后的运动学模型更能够描述实体仿生机器鱼的游动特性。最后,将修正后的运动学模型,运用到三关节仿生机器鱼上进行实验,结果表明,该模型能够有效地抑制仿生机器鱼头部摆动,进而提高了仿生机器鱼的游动速度。     

水下仿生机器鱼的研究进展IV——多仿生机器鱼协调控制研究

本文探讨了多仿生机器鱼群体游动协调的问题，这是仿生机器鱼技术研究的一个新的 方向，目前尚无人涉足．首先研制了一套具有高效、高机动性的微小型多机器鱼平台，提出 了基于AGENT的网格算法进行多机器鱼的定位和协调控制，利用该实验平台，进行了多机器 鱼对抗和多机器鱼协调过孔的实验研究．     

水下仿生机器鱼的研究进展I——鱼类推进机理

仿生机器鱼技术是近年来水下机器人领域研究的热点之一 ,它为研制高效、高机动性和低噪声的水下运载器提供了新的思路 .本文以鱼的脊椎曲线为研究对象 ,提出了一种新的鱼类推进机理——波动推进 ,分析了波动推进过程中的运动阻力 .通过鱼类游动观测实验和仿生机器鳗鱼的研制 ,验证了该理论的有效性     

单驱动仿生机器鱼加速-滑行动态特性的数值研究

通过变截面悬臂梁受迫振动响应模拟鱼体变形,设计了单驱动仿生机器鱼.建立了机器鱼自主游动中变形体耦合动力学方程,运用数值仿真研究的方法探讨了其"加速-滑行"游动模式的动力特性.发现可以通过加速时间和滑行时间的组合得到更高的游动效率,拓展了机器鱼的高效运动控制模式.     

仿生机器鱼运动控制方法综述

运动控制是仿生机器鱼研究的核心问题,为此,依据解决运动控制问题的不同思路,总结了仿生机器鱼运动控制常见的几种研究方法:基于杆系结构的鱼体波曲线拟合法、正弦控制器方法和基于中枢模式发生器模型的方法,分别对3种运动控制方法的基本原理和特点进行了总结和归纳,分析了3种方法在可靠性、稳定性和实时性等方面的优缺点,最后指出了仿生机器鱼运动控制方法的发展趋势。     

Purcell’s swimmer revisited

Purcell’s swimmer was proposed by E. M. Purcell to explain bacterial swimming motions. It has been proved experimentally that a swimmer of this kind is possible under inertial-less and high viscous environment. But we could not investigate all the aspects of this mechanism through experiments due to practical difficulties. The computational fluid dynamics (CFD) provides complementary methods to experimental fluid dynamics. In particular, these methods offer the means of testing theoretical advances for conditions unavailable experimentally. Using such methodology, we have investigated the fluid dynamics of force production associated with the Purcell’s swimmer. By employing dynamic mesh and user-defined functions, we have computed the transient flow around the swimmer for various stroke angles. Our simulations capture the bidirectional swimming property successfully and are in agreement with existing theoretical and experimental results. To our knowledge, this is the first CFD study which shows the fact that swimming direction depends on stroke angle. We also prove that for small flapping frequencies, swimming direction can also be altered by changing frequency-showing breakdown of Stokes law with inertia.     

Development of a humanoid robot for underwater use

In this research, we have developed a swimming robot with a fluttering kick with two legs, which can swim freely both on the surface of water and under water. We have established a control method for all the different types of motion of this robot, e.g., swimming in a straight line, turning, diving, or rising up in the water. Furthermore, by optimizing the three-dimensional action of this underwater robot, we can expect an improvement in its performance for complex work.     

基于教学设计的虚拟实验中心研究

结合教学设计的基本理论,在系统分析虚拟实验构成要素的基础上,重点研究了虚拟实验中心应具有的功能,并按照实验流程设计了六大功能模块,为虚拟实验中心的建设研究提供了一些参考。     

Sample size calculation for non-compliance randomized trials with repeated measurements in binary data

When we have difficulty in recruiting patients into a randomized clinical trial (RCT), we may consider taking more than one measurement per patient to reduce the number of patients needed to achieve a desired power. In this paper, we consider a double blind RCT with two courses of treatment per patient. At each course, a patient assigned to the experimental treatment could switch to receive the placebo if the patient declined his/her assigned (experimental) treatment, and a patient assigned to the placebo could switch to receive the experimental treatment if the patient refused his/her assigned (placebo) treatment as well. Sample size calculation without accounting for this non-compliance can be inadequate when we apply the standard procedure of intention-to-treat analysis for non-compliance trials to test no treatment effect. Based on the simple additive risk model proposed elsewhere, we have incorporated the initial probability of compliance, the dependence of patient's selection of a treatment on his/her previous response, and the variation of probabilities of response between patients into sample size determination. We have included a quantitative discussion that provides an insight into the effect of various parameters on the minimum required sample size. We have also noted the situation in which taking repeated measurements per patient can be most effective to reduce the number of patients needed to maintain a given power.     

Development of ICPF Actuated Underwater Microrobots

It is our target to develop underwater microrobots for medical and industrial applications. This kind of underwater microrobots should have the characteristics of flexibility,good response and safety. Its structure should be simple and it can be driven by low voltage and produces no pollution or noise. The low actuating voltage and quick bending responses of Ionic Conducting Polymer Film (ICPF) are considered very useful and attractive for constructing various types of actuators and sensors. In this paper, we will first study the characteristics of the ICPF actuator used in underwater microrobot to realize swimming and walking. Then, we propose a new prototype model of underwater swimming microrobot utilizing only one piece of ICPF as the servo actuator. Through theoretic analysis, the motion mechanism of the microrobot is illustrated. It can swim forward and vertically. The relationships between moving speed and signal voltage amplitude and signal frequency is obtained after experimental study. Lastly, we present a novel underwater crab-like walking microrobot named crabliker-1.It has eight legs, and each leg is made up of two pieces of ICPF. Three sample processes of the octopod gait are proposed with a new analyzing method. The experimental results indicate that the crab-like underwater microrobot can perform transverse and rotation movement when the legs of the crab collaborate.     

运用仿真技术优化泳池清洁机器人的路径规划设计

在泳池清洁机器人的设计过程中,为优化路径规划设计,提出了运用计算机仿真程序模拟工作环境进行仿真实验的方法,并对仿真结果进行了详细的对比分析,为研究和设计移动机器人路径规划提供一定的帮助.     

A new type of hybrid fish-like microrobot

In order to develop a new type of fish-like microrobot with swimming, walking, and floating motions, in our past research, we developed a hybrid microrobot actuated by ionic conducting polymer film (ICPF) actuators. But the microrobot had some problems in walking and floating motions. In this paper, we propose a concept of hybrid microrobot (see Fig. 1). The microrobot is actuated by a pair of caudal fins, a base with legs and an array of artificial swim bladders. We have developed a prototype of the base with legs and one artificial swim bladder, respectively, and carried out experiments for evaluating their characteristics. Experimental results show the base with legs can realize walking speed of 6 mm/s and rotating speed of 7.1 degrees/s respectively, and the prototype of the artificial swim bladder has a maximum floatage of 2.6 mN. The experimental results also indicate that the microrobot has some advantages, such as walking motion with 2 degrees of freedom, the walking ability on rough surface (sand paper), the controllable floatage, etc. This kind of fish-like microrobot is expected for industrial and medical applications.     

运用EXCEL函数进行区组试验设计

区组设计是科学研究和加工工艺中经常用到的试验设计方法,本文通过对区组设计中的配对设计和完全区组设计实质的分析,提出了运用EXCEL进行配对设计和完全区组设计的方法。结果认为灵活利用Excel的随机函数如RAND、RANDOMBE-TWEEN等和排序按钮可以快速进行区组试验设计。