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Effect of Spanwise Flexibility on propulsion performance of a Flapping Hydrofoil at Low reynolds Number

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Chinese Journal of Mechanical Engineering 2012年第1期25卷 12-19页

作者： bi shusheng cai yueri robotics institute Beihang UniversityBeijing 100191China

Spanwise flexibility is a key factor influencing propulsion performance of pectoral foils. performances of bionic fish with oscillating pectoral foils can be enhanced by properly selecting the spanwise flexibility. The influence law of spanwise flexibility on thrust generation and propulsion efficiency of a rectangular hydro-foil is discussed. Series foils constructed by the two-component silicon rubber are developed. NACA0015 shape of chordwise cross-section is employed. The foils are strengthened by fin rays of different rigidity to realize variant spanwise rigidity and almost the same chordwise flexibility. Experiments on a towing platform developed are carried out at low reynolds numbers of 10 000, 15 000, and 20 000 and Strouhal numbers from 0.1 to 1. The following experimental results are achieved: (1) The average forward thrust increases with the St number increased; (2) Certain degree of spanwise flexibility is beneficial to the forward thrust generation, but the thrust gap is not large for the fins of different spanwise rigidity; (3) The fin of the maximal spanwise flexibility owns the highest propulsion efficiency; (4) Effect of the reynolds number on the propulsion efficiency is significant. The experimental results can be utilized as a reference in deciding the spanwise flexibility of bionic pectoral fins in designing of robotic fish prototype propelled by flapping-wing.

关键词： spanwise flexibility flapping motion thrust generation propulsion efficiency low reynolds number

bionic Flapping pectoral Fin with Controllable Spatial Deformation

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Journal of bionic Engineering 2019年第5期16卷 916-930页

作者： yueri cai Lingkun Chen shusheng bi Guoyuan Li Houxiang Zhang robotics institute Beihang UniversityBeijing 100191China Department of Ocean Operations and Civil Engineering Norwegian University of Science and TechnologyAalesund 6025Norway

This paper presents the design of a bionic pectoral fin with fin rays driven by multi-joint *** by the cownose ray,the bionic pectoral fin is modeled and simplified based on the key structure and movement parameters of the cownose ray's pectoral fin.A novel bionic propulsion fin ray composed of a synchronous belt mechanism and a slider-rocker mechanism is designed and optimized in order to minimize the movement errors between the designed fin rays and the spanwise curves observed from the cownose ray,and thereby reproducing an actively controllable flapping deformation.A bionic flapping pectoral fin prototype is developed *** verify that the bionic pectoral fin flaps consistently with the design rule extracted from the cownose *** in a towing tank are set up to test its capability of generating the lift force and the propulsion *** movement parameters within the usual propulsion capabilities of the bionic pectoral fm are utilized:The flapping frequency of 0.2 Hz-0.6 Hz,the flapping amplitude of 3°-18°,and the phase di^rence of 10°-60°.The results show that the bionic pectoral fin with actively controllable spatial deformation has expected propulsion performance,which supports that the natural features of the cownose ray play an important role in designing and developing a bionic prototype.

关键词： cownose ray bionic pectoral fin controllable deformation multiple fin rays propulsion perfonnance

Spatial-channel transformer network based on mask-rCNN for efficient mushroom instance segmentation

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International Journal of Agricultural and biological Engineering 2024年第4期17卷 227-235页

作者： Jiaoling Wang Weidong Song Wengang zheng Qingchun Feng Mingfei Wang Chunjiang Zhao Northwest Agriculture and Forestry university Xi’an 712199China Nanjing institute of Agricultural Mechanization Ministry of Agriculture and Rural AffairsNanjing 210014China Intelligent equipment Technology research Center Beijing Academy of Agriculture and Forestry SciencesBeijing 100097China Zhejiang provincial Key Laboratory of Agricultural Intelligent Equipment and roboics/College of biosystems Engineering and Food Science Zhejiang UniversityHangzhou 310058China

Edible mushrooms are rich in nutrients;however,harvesting mainly relies on manual *** localization of each mushroom is necessary to enable a robotic arm to accurately pick edible *** studies used detection algorithms that did not consider mushroom pixel-level *** these algorithms are combined with a depth map,the information is ***,in instance segmentation algorithms,convolutional neural network(CNN)-based methods are lightweight,and the extracted features are not *** guarantee real-time location detection and improve the accuracy of mushroom segmentation,this study proposed a new spatial-channel transformer network model based on Mask-CNN(SCT-Mask-rCNN).The fusion of Mask-rCNN with the self-attention mechanism extracts the global correlation outcomes of image features from the channel and spatial ***,Mask-rCNN was used to maintain a lightweight structure and extract local features using a spatial pooling pyramidal structure to achieve multiscale local feature fusion and improve detection *** results showed that the SCT-Mask-rCNN method achieved a segmentation accuracy of 0.750 on segm_precision_mAp and detection accuracy of 0.638 on Bbox_precision_*** to existing methods,the proposed method improved the accuracy of the evaluation metrics Bbox_precision_mAp and segm_precision_mAp by over 2%and 5%,respectively.

关键词： edible mushrooms picking instance segmentation deep learning algorithm

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基于平行面多靶标标定的单目大视场平面测量

光学学报 2017年第10期37卷 228-239页

作者：杨东升毕树生蔡月日袁畅北京航空航天大学机器人研究所北京100191

针对单目大视场平面测量时,测量平面内不便布置靶标和大尺寸靶标难以制作的问题,提出一种利用布设在平行面上的小尺寸平面靶标进行标定的方法。选定一个平行面为标定平面,将单个小尺寸平面靶标合理放置在标定平面的多个位置拍摄,整合构... 详细信息

针对单目大视场平面测量时,测量平面内不便布置靶标和大尺寸靶标难以制作的问题,提出一种利用布设在平行面上的小尺寸平面靶标进行标定的方法。选定一个平行面为标定平面,将单个小尺寸平面靶标合理放置在标定平面的多个位置拍摄,整合构造出一个大尺寸平面靶标,采用非线性优化的方法进行摄像机内、外参的优化求解。结合平行约束和距离参数得到测量平面与图像平面的单应矩阵,实现大视场平面测量。建立平面测量的精度模型,对测量区域各处精度的分布以及影响测量精度的摄像机内参、安装角度和高度等因素进行理论分析和实验验证。实验结果表明:该方法可有效保证整体测量精度;在上底920mm、下底1360mm、高920mm的梯形视场内标定,距标定平面200mm的测量平面内的测量误差低于0.6%;测量区域内各处误差的分布趋势与精度模型一致。此方法完全适用于大视场平面测量。

关键词：机器视觉大视场平面测量平行面标定精度分析非线性优化

面向LQG控制的IEEE 802.11ax网络资源调度方法

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通信学报 2024年第3期45卷 81-91页

作者：郑萌张雷梁炜中国科学院沈阳自动化研究所机器人学国家重点实验室辽宁沈阳110016 中国科学院网络化控制系统重点实验室辽宁沈阳110016 中国科学院机器人与智能制造创新研究院辽宁沈阳110169 中国科学院大学计算机科学与技术学院北京100049

由于低成本、易维护和频带免授权等优点,IEEE 802.11ax网络被广泛用于工业控制应用。针对基于IEEE802.11ax的无线网络化控制系统,提出一种控制感知的资源调度方法以支持对多个控制系统的无线高速控制。首先,考虑IEEE802.11ax网络的传感... 详细信息

由于低成本、易维护和频带免授权等优点,IEEE 802.11ax网络被广泛用于工业控制应用。针对基于IEEE802.11ax的无线网络化控制系统,提出一种控制感知的资源调度方法以支持对多个控制系统的无线高速控制。首先,考虑IEEE802.11ax网络的传感数据丢包问题,给出控制系统的最优估计器和线性二次高斯(LQG)控制。然后,分析LQG指标与IEEE 802.11ax传输可靠性的依赖关系,给出期望LQG指标最小化的资源调度问题模型,进而提出一种面向LQG控制的资源调度(LCArS)方法。最后,通过大量仿真验证LCArS的有效性。LCArS可用于自动导引车集群导航、机器人远程控制等智能工厂应用。

关键词：网络化控制系统无线网络线性二次高斯控制资源调度可靠性

Control of a Spherical robot: path Following Based on Nonholonomic Kinematics and Dynamics

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Chinese Journal of Aeronautics 2011年第3期24卷 337-345页

作者： zheng Minghui ZHAN Qiang LIU Jinkun cai Yao robotics institute Beihang University Beijing 100191 China School of Automation Science and Electrical Engineering Beihang University Beijing 100191 China

This paper presents the controller design for the path following of a spherical mobile robot, BHQ-1. Firstly, a desired velocity for the reference path is deduced from the kinematic model, which cannot be transformed into the classic chained form. Secondly, a necessary torque for the desired velocity is obtained based on the dynamic model. As to the kinematics, a one-dimensional function is selected to measure the two-directional tracking error, and the velocity of rolling forward is reasonably assumed to be constant; therefore the multiple-input multiple-output （MIMO） system is transformed into a single-input single-output （SISO） system. As to the dynamics, both exact dynamics and inexact dynamics with modeling error as well as bounded unknown disturbance are taken into account, based on which a proportional-derivative （pD） controller and a sliding mode controller with adaptive parameters are proposed respectively. Finally, convergence analysis and simulation results are provided to validate these controllers.

关键词： spherical robot path following nonholonomic kinematics dynamics

research on point stabilization of a wheeled mobile robot using fuzzy control optimized by GA

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The Journal of china Universities of posts and Telecommunications 2011年第5期18卷 108-113页

作者： CAO zheng-cai ZHAO Ying-tao FU Yi-li College of Infornaation Science and Technology Beijing University of Chemical Technology Beijing 100029 China The State Key Laboratory of robotics and Systems Harbin Institute of Technology Harbin 150001 China

A point stabilization scheme of a wheeled mobile robot （WMr） which moves on uneven surface is presented by using tuzzy control. Taking the kinematics and dynamics of the vehicle into account, the fuzzy controller is employed to regulate the robot based on a kinematic nonlinear state feedback control law. Herein, the fuzzy strategy is composed of two velocity control laws which are used to adjust the speed and angular velocity, respectively. Subsequently, genetic algorithm （GA） is applied to optimize the controller parameters. Through the self-optimization, a group of optimum parameters is gotten. Simulation results are presented to show the effectiveness of the control strategy.

关键词： wheeled mobile robot point stabilization fuzzy control genetic algorithm

基于实例对比学习的遥感建筑物变化检测域适应算法

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遥感学报 2024年第7期28卷 1771-1788页

作者：张奇路遥王飞张雪涛郑南宁西安交通大学人机混合增强智能全国重点实验室西安710049 西安交通大学视觉信息与应用国家工程研究中心西安710049 北京市遥感信息研究所北京100011 西安交通大学人工智能与机器人研究所西安710049

建筑物变化检测是遥感影像智能解译中的重要研究方向。针对建筑物变化检测的跨域变化检测算法中存在的像素级对比学习噪声过大和目标域样本利用不充分等问题,本文提出了实例级对比学习域适应变化检测算法ICDA-CD。首先,使用区域级域混... 详细信息

建筑物变化检测是遥感影像智能解译中的重要研究方向。针对建筑物变化检测的跨域变化检测算法中存在的像素级对比学习噪声过大和目标域样本利用不充分等问题,本文提出了实例级对比学习域适应变化检测算法ICDA-CD。首先,使用区域级域混合替代实例级域混合,以实现源域和目标域图像的有效混合;然后,利用实例级对比学习,降低伪标签噪声的影响。具体来说,在编码器中,拉开变化实例区域双时相特征距离,并在解码器中,拉近各个变化实例特征之间的距离,这可以显著提升模型对源域和目标域特征表示的一致性;最后,在损失计算部分使用伪标签质量估计,使得低置信度区域的像素也可以参与训练,提高了目标域样本的利用率。将本文方法与DACS、DAFormer、和HrDA等3种目前先进的算法进行实验对比。结果表明本文所提出来的方法在LEVIr-CD域迁移至S2Looking以及S2Looking域迁移至LEVIr-CD时F1分数分别达到了43.91%和74.75%,优于几种先进的算法。

关键词：遥感图像建筑物变化检测对比学习域适应深度学习伪标签

面向空地协同的旋翼无人机动平台自主降落最优轨迹生成

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机器人 2024年第3期46卷 266-274,283页

作者：郑勇杰张广玉杨丽英黄朝雄中国科学院沈阳自动化研究所机器人学国家重点实验室辽宁沈阳110016 中国科学院机器人与智能制造创新研究院辽宁沈阳110169 中国科学院大学北京100049

旋翼无人机在移动平台上快速自主降落能够提升空地机器人的任务适应性和作业灵活性,对提高任务响应速度和增强救援能力具有重要意义。为了使旋翼无人机在最短时间内安全降落到移动平台,本文提出了一种最优升力分解轨迹生成方法,旨在在... 详细信息

旋翼无人机在移动平台上快速自主降落能够提升空地机器人的任务适应性和作业灵活性,对提高任务响应速度和增强救援能力具有重要意义。为了使旋翼无人机在最短时间内安全降落到移动平台,本文提出了一种最优升力分解轨迹生成方法,旨在在升力有限的情况下,最大化旋翼无人机的飞行性能。该方法首先对旋翼无人机的有限升力进行分解,获得最优的3轴升力分配,然后将非线性加速度约束转化为动态线性约束,最后根据最优控制理论求解出最优飞行时间轨迹。仿真结果表明了本文提出的算法能够保证轨迹生成的准确性和稳定性,并且该算法的计算效率高,能够满足系统实际应用中的实时性要求。

关键词：旋翼无人机空地协同轨迹生成升力分解动平台降落