低损耗薄膜铌酸锂光集成器件的研究进展

近年来得益于薄膜铌酸锂晶圆离子切片技术和低损耗微纳刻蚀工艺的飞速发展,薄膜铌酸锂光集成结构提供了光场紧束缚、快速电光调谐、高效频率转换和声光转换的空前能力,各种高性能的薄膜铌酸锂光集成器件不断涌现,且朝着大规模光集成芯片的方向迅猛发展,为高速信息处理、精密测量、量子信息、人工智能等重要应用提供了全新的发展动力。本文主要围绕铌酸锂晶体发展历史、薄膜铌酸锂离子切片技术发展历程、极低损耗微纳刻蚀技术演化进程,以及高性能的薄膜铌酸锂光集成器件进展进行总结,并展望了未来的发展趋势。

基于光照模型的细胞内镜图像不均匀光照校正算法

细胞内镜需实现最大倍率约500倍的连续放大成像,受光纤照明及杂散光的影响,其图像存在不均匀光照,且光照分布会随放大倍率的变化而变化。这会影响医生对病灶的观察及判断。为此,本文提出一种基于细胞内镜光照模型的图像不均匀光照校正算法。根据图像信息由光照分量和反射分量组成这一基础,该算法通过卷积神经网络学习图像的光照分量,并基于二维Gamma函数实现不均匀光照校正。实验表明,经本文方法进行不均匀光照校正后,图像的光照分量平均梯度和离散熵分别为0.22和7.89,优于自适应直方图均衡化、同态滤波和单尺度Retinex等传统方法以及基于深度学习的WSI-FCN算法。

有源降噪通路辨识的人因参数几何模型

研究了一种基于人因参数几何模型的声学通路辨识策略,可用于有源降噪技术中的通路辨识环节,以降低因人体姿态改变而导致的降噪性能退化。该策略利用深度相机输出的点云数据提取人因参数并构建几何模型,通过仿真和人工神经网络预测声学通路的传递函数矩阵。结果表明,人因参数几何模型的降噪性能与点云模型接近,适用于参数化扫描仿真。进一步通过实验验证了仿真的准确性以及所提策略的可行性。实验结果还表明,人体姿态改变会导致声学通路传递函数发生复杂且显著的变化,说明实际应用应考虑人体姿态改变所带来的影响。

全景内窥成像技术及应用

全景内窥成像技术可有效减小体内器官的观察盲区,具有缩短手术时间、降低术中出血风险、改善手术预后、缩短术后恢复时间等多种优点,在微创手术和术前检查中有重要应用价值,是近年来的研究热点。本文从原理和产品应用两个方面对全景内窥成像技术进行了梳理。首先,综述了基于二维和三维成像的各种全景内窥成像技术,阐述了它们各自的实现方式,并分析了其关键指标和性能。其次,对比分析了由全景内窥成像技术衍生出来的胶囊内窥镜、全景结直肠镜等多种不同类型的产品,并展望了全景内窥成像技术的发展趋势和应用前景。

基于多模态传感的交互式手套系统

触觉交互是人感知周围环境的重要途径,如果再现的触觉信息系统不能向使用者传达清晰的含义,使用者就没有了操作的真实感。因此提出了一种基于多模态传感的交互式手套系统,实现了人机交互过程中的触觉再现,向使用者提供完整的触觉信息。系统的触觉再现手套集成了手部运动驱动、振动触感再现、冷热触感再现功能,能够广泛应用于VR/AR、人工智能、医疗手术、机器人、游戏娱乐、特殊教育等领域。

基于Cortex-M3的汉盲翻译SoC设计

汉盲翻译是一种将中文文本自动翻译为对应的盲文数据的过程.在嵌入式环境下,汉盲翻译的速度较慢,难以达到复杂环境下的实时性需求.为此设计出专用的汉盲翻译IP核,通过实现逆向最大匹配分词算法、汉盲转换,最终得到准确的盲文数据.为了验证设计的合理性,以Cortex-M3为微处理器构建SoC,搭载串口、LCD驱动和汉盲翻译IP核,并使用FPGA实验平台进行功能验证和性能测试.测试结果表明,该SoC可准确进行汉盲翻译,翻译速度达5 079.37 B/s.

Knot-inspired optical sensors for slip detection and friction measurement in dexterous robotic manipulation

Friction plays a critical role in dexterous robotic manipulation.However,realizing friction sensing remains a challenge due to the difficulty in designing sensing structures to decouple multi-axial forces.Inspired by the topological mechanics of knots,we construct optical fiber knot(OFN)sensors for slip detection and friction measurement.By introducing localized self-contacts along the fiber,the knot structure enables anisotropic responses to normal and frictional forces.By employing OFNs and a change point detection algorithm,we demonstrate adaptive robotic grasping of slipping cups.We further develop a robotic finger that can measure tri-axial forces via a centrosymmetric architecture composed of five OFNs.Such a tactile finger allows a robotic hand to manipulate human tools dexterously.This work could provide a straightforward and cost-effective strategy for promoting adaptive grasping,dexterous manipulation,and human-robot interaction with tactile sensing.

A bioinspired flexible optical sensor for force and orientation sensing

Flexible optical sensors have been an emerging paradigm for applications in robotics,healthcare,and human–machine interfaces due to their high sensitivity,fast response,and anti-electromagnetic interference.Recently,Marques reports a bioinspired multifunctional flexible optical sensor(BioMFOS),achieving a forces sensitivity of 13.28μN,and a spatial resolution of 0.02 mm.The BioMFOS has a small dimension(around 2 cm)and a light weight(0.8 g),making it suitable for wearable application and clothing integration.As proof-of-concept demonstrations,monitoring of finger position,trunk movements,and respiration rate are realized,implying their prominent applications in remote healthcare,intelligent robots,assistance devices teleoperation,and human-machine interfaces.

微尺度手性阵列光场的生成与调控特性研究

通过在入射光引入平移位相因子,从而实现了一种基于Richards‑Wolf矢量衍射理论的微尺度手性阵列光场的生成。通过模拟研究,进一步实现了阵列尺寸、阵列子单元手性的灵活调控。此外,探究了阵列的传播特性,在±λ传播距离内手性阵列光场均保持光场模式分布。该研究极大的丰富了手性强度光场的模式,在手性微纳材料的制备等领域具有良好的应用前景。

使用零力矩点反馈的双足机器人惯性参数辨识

为解决基于关节力矩的双足机器人参数辨识方法辨识精度不高,基于完整的足底力信息和运动捕捉数据的辨识方法对实验条件要求较高的问题,提出基于ZMP(zero moment point)数据的双足机器人惯性参数辨识方法。将理论ZMP与实际ZMP的位置偏差作为目标函数,考虑参数范围和机器人总质量两类约束条件,建立只使用双足机器人自身传感器采样数据的惯性参数辨识优化模型。针对所建模型无法拆分成线性形式的问题,推导目标函数关于参数矢量的梯度矢量和海塞矩阵,并给出了基于最速下降法和牛顿法的优化求解算法。使用GoRoBoT-II机器人的双足部分,进行腿部杆件的惯性参数辨识实验,将所提出方法得到的辨识结果与传统基于关节力矩的辨识结果进行对比,发现基于ZMP的辨识方法的结果更接近于三维几何建模得到的参数标称值,且理论ZMP与实际ZMP的偏差均值为4.6 mm,小于传统基于力矩辨识方法的12.4 mm,说明所提出的基于ZMP的惯性参数辨识方法能够得到比传统方法更好的结果。

跨尺度光学内窥成像技术

光学成像技术具备高分辨、多尺度、多维度、易集成以及低辐射等优势,在生物医学领域发挥重要的作用。在内窥镜领域,如何进行内窥图像信息的获取、处理及可视化是光学成像技术要解决的核心问题,在医学临床中获取内窥镜所观察部位的跨尺度图像有利于医师对于患者病情的诊断以及提升术中操作的精确程度。本文从跨尺度光学成像技术在内窥镜领域的应用入手,重点阐述了目前内窥镜临床中用于获取跨尺度图像的光学系统类型,包括跨尺度变焦光学系统、光纤扫描成像系统、多通道成像系统等,说明了这些跨尺度光学内窥镜系统如何获取跨尺度图像,并对跨尺度光学成像在内窥镜领域的未来发展做了展望。

基于国家通用盲文标调规则的汉盲转换系统

信息时代推进盲文数字化,关乎我国广大盲人文化素质的提高和生活水平的改善.本文实现了一种基于国家通用盲文标调规则的汉盲转换系统,能够快速生成海量符合国家通用盲文方案的数字化资源,满足视障人士无障碍获取信息的需求.此系统按通用盲文规则处理汉语文本,将其转换为符合标调规则、简写规则的盲文结果.测试结果表明,此系统可以准确处理标调规则、简写规则,可得到准确的符合国家通用盲文方案的盲文数字化结果.声调省写覆盖率、韵母简写覆盖率和篇幅增加量均与国家通用盲文方案的理论值相当,能够快速处理长篇语料文件,程序执行效率高,具有实用价值,可以用于推广国家通用盲文,促进我国盲文数字化无障碍建设.

Multidirectional 3D printed functionally graded modular joint actuated by TCPFL muscles for soft robots

Highly deformable bodies are essential for numerous types of applications in all sorts of environments. Joint-like structures comprising a ball and socket joint have many degrees of freedom that allow mobility of many biomimetic structures. Recently, soft robots are favored over rigid structures for their highly compliant material, high-deformation properties at low forces, and ability to operate in di fficult environments. However, it is still challenging to fabricate complex designs that satisfy application constraints due to the combined e ffects of material properties, actuation method, and structural geometry on the performance of the soft robot. Therefore, a combination of a rigid joint and a soft body can help achieve modular robots with fully functional body morphology. Yet, the fabrication of soft parts requires extensive molding for complex shapes, which comprises several processes and can be time-consuming. In addition, molded connections between extremely soft materials and hard materials can be critical failing points. In this paper, we present a functionally graded 3D-printed joint-like structure actuated by novel contractile actuators. Functionally graded materials (FGMs) via 3D printing allow for extensive material property enhancement and control which warrant tunable functionalities of the system. The 3D-printed structure is made of 3 rigid ball and socket joints connected in series and actuated by integrating twisted and coiled polymer fishing line ( TCPFL) actuators, which are con fined in the FGM accordion-shaped channels. The implementation of the untethered T CPFL actuation system can be highly bene ficial for deployment in environments that require low vibrations and silent actuation. The fishing line TCP actuators produce an actuation strain up to 40% and bend the joint up to 40° in any direction. The T CPFL can be actuated individually or as a group to control the bending trajectory of the modular joint, which is bene ficial when deployed in areas that contain small crevices. Obtaining complex modes of bending, the FGM multidirectional joint demonstrated a great potential to achieve di fferent functionalities such as crawling, rolling, swimming, or underwater exploration.

基于柱矢量光调控的纵向超分辨率准球形多焦点阵列

激光多焦点阵列以兼具更高的光场操控自由度和焦斑单元高空间分辨率的特点,被广泛应用在光学诱捕以及飞秒激光微纳制造等领域。然而由于阵列中焦斑的纵向分辨率弱于横向分辨率,在激光加工应用中限制了其对各向同性结构的加工能力。因此,本文提出一种基于柱矢量光调控生成纵向超分辨准球形多焦点阵列的方法。利用对柱矢量光的两组基径向偏振光和角向偏振光分别进行聚焦调控,结合环形衰减调制可形成纵向超分辨焦斑,再将两种偏振光场以适当的振幅比例在焦区叠加,从而合成准球形多焦点阵列。实验结果表明,10×10的多焦点阵列中各焦斑尺寸均一,具有近球形光强分布。其中,阵列中所有焦点的纵向半高全宽的平均值为0.76λ、标准差为0.005λ,横向半高全宽的平均值为0.76λ、标准差为0.019λ。该具有高尺寸均一性的准球形多焦点阵列可为激光微纳加工精准制备微纳器件提供新的途径。

Research of 6-DOF Serial-Parallel Mechanism Platform for Stability Training of Legged-Walking Robot

The concept of legged-robot stability training with a training platform is proposed and a serial-parallel mechanism platform with 6 degrees of freedom is designed for this target. The designed platform is composed of 4-DOF parallel mechanism with spherical joints and prismatic pairs,and 2-DOF serial mechanism with prismatic pairs. With this design,the platform has advantages of low platform countertop,big workspace,high carrying capacity and high stiffness. On the basis of DOF analysis and computation of space mechanism,weight supporting auxiliary mechanism and raceways-balls supporting mechanism are designed,so as to improve the stiffness of designed large platform and payload capacity of servo motors. And then the whole structure design work of the platform is done. Meanwhile,this paper derives the analytical solutions of forward kinematics, inverse kinematics and inverse dynamics. The error analysis model of position and orientation is established. And then the simulation is done in ADAMS to ensure the correctness and feasibility of this design.

Controller design based on viscoelasticity dynamics model and experiment for flexible drive unit

In order to ensure that the system has the advantage of light weight and vibration absorption, the steel rope is used as a flexible transmission part. A flexible drive unit(FDU) is developed, whose features are guided by steel rope, increasing force by the movable pulley group, modular, convenient and flexible. Dynamics model for controller is deduced based on the constitutive equation of viscoelasticity. Controller is designed for position control and is based on the viscoelasticity dynamics model compensation control strategy proposed. The control system is based on the TURBO PMAC multi-axis motion control card.Prototype loading experiments and velocity experiments results show that the FDU can reach 2 Hz with no load and the max speed of 30(°)/s. The FDU has the capability of the load torque 11.2 N·m and the speed of 24(°)/s simultaneously, and the frequency response is 1.3 Hz. The FDU can be used to be the pitch joint of hip for biped robot whose walking speed is 0.144 km/h theoretically.

Static Force-Based Modeling and Parameter Estimation for a Deformable Link Composed of Passive Spherical Joints With Preload Forces

To balance the contradiction between higher flexibility and heavier load bearing capacity,we present a novel deformable manipulator which is composed of active rigid joints and deformable links.The deformable link is composed of passive spherical joints with preload forces between socket-ball surfaces.To estimate the load bearing capacity of a deformable link,we present a static force-based model of spherical joint with preload force and analyze the static force propagation in the deformable link.This yields an important result that the load bearing capacity of a spherical joint only depends on its radius,preload force,and static friction coefficient.We further develop a parameter estimation method to estimate the product of preload force and static friction coefficient.The experimental results validate our model.80.4%of percentage errors on the maximum payload mass prediction are below 15%.

内窥环境下多光谱血氧饱和度检测

采用蒙特卡罗模拟技术对血管组织在可见光波段的多光谱成像进行建模仿真,通过分析不同血氧饱和度下血液后向散射功率的绝对值、相对值、绝对差值和对比度,并考虑可能的干扰因素,优选出适合内窥环境下使用的450 nm、525 nm、630 nm和660 nm 4个成像波段。基于4个优选的成像波段展开了血氧饱和度检测的实验验证。在血管仿体组织上的实验结果表明,在95%的置信水平下,血氧饱和度的检测偏差为1.24%。研究结果验证了利用四波段进行内窥组织血氧饱和度检测的可行性。

光热镊技术与应用研究进展

自激光技术问世以来,光镊作为一种非接触、高精度的颗粒操控工具,已广泛应用于生物、化学等领域。然而光热效应引起的热对流及热损伤等问题,极大地限制了传统光镊技术的捕获性能和捕获样品活性。为突破这一限制,研究者们开始探索将光与热相结合的颗粒捕获与操控技术,发现可以通过材料的光致发热或致冷效应,将热场转化为颗粒捕获的一大助力,进而提出多种新颖的光热镊技术。相比于传统光镊,光热镊技术利用光场和热场的共同作用,具有更低的激光能量需求和更高的捕获精度,在生物医学等领域中展现出巨大应用潜力。系统性地阐述光热镊的基本原理,详细介绍代表性的光热镊技术的发展和应用,并分析该技术面临的问题、发展趋势和发展前景,旨在帮助研究者系统了解基于光热效应的光热镊基本知识、最新研究进展和潜在应用,为该领域的科学研究提供参考。

微观探索的新光芒:便携式光声显微成像技术(特邀)

光声成像(PAI)是一种结合了光学成像高对比度和超声成像深穿透性的生物医学成像模态,近年来得到了迅速发展。其中,光声显微成像(PAM)作为光声成像的重要实现方式之一,可以在毫米级的成像深度上实现微米级甚至百纳米级的分辨率,能够实现对生物组织结构、功能和分子的高分辨率成像,已在临床诊断、皮肤病检测和眼科等领域得到广泛应用。首先对PAM的工作原理和实现方式等进行基本介绍,之后围绕便携式PAM技术,从手持与半手持式、脑部可穿戴式及集成多模态3方面对其研究进展进行综述,随后探讨便携式PAM技术面临的挑战,最后进行总结与展望。