这项工作部分得到了中国国家自然科学基金62103308和62073247）的支持，部分得到了中央高校基础科研业务费（2042023kf0095）的支持，部分得到了中国博士后科学基金（2022T150496）的支持，部分得到了WHU-2022-SYJS-10（WHU-2022-SYJS-10）资助的武汉大学实验技术项目资助。

本研究符合武汉大学人类研究伦理委员会的指导，所有实验数据均获得知情同意。本文讨论了双倒摆系统的实验步骤，所有步骤均在基于WebVR的NCSLab中进行。
1. 接入基于WebVR的NCSLab系统
<ol><li>打开支持 WebVR 的 Web 浏览器。输入基于WebVR的NCSLab的统一资源定位符（URL）以访问系统。</li>
	<li>点击 Start Experiment 按钮，登录 NCSLab 系统。如果是第一次登录系统，请进行帐户注册。</li>
	<li>登录 NCSLab 系统，从左侧菜单栏选择不同的实验，本例中选择双倒摆实验。</li>
	<li>访问主页上的 3D 子页面。 注意：主页上有五个子页面，从第一个开始，这是设备模型的介绍。它包含一个3D模型动画以及文档。通过访问此页面，用户可以掌握双倒摆系统的原理，从而方便地执行后续实验。</li>
	<li>点击“请求控制”按钮申请实验控制，确保资源的高效利用。这将为用户提供 30 分钟的实验时间。 注意：对于虚拟实验，可以允许 500 个用户同时进行实验。</li>
	<li>进入植物信息子页面，获取有关实验设备的全面详细信息。这包括有关当前正在使用的设备、未使用的设备以及与维护相关的设备的信息。</li>
	<li>选择要在 “实验算法 ”子页面上下载的系统默认控制算法。或者，继续访问 “算法设计 ”子页面以设计不同的算法。<ol><li>要设计新的控制算法，请点击算法设计子页面的创建 新模型按钮 ，进入设计界面。 注意：算法设计过程与MATLAB/Simulink的过程非常相似，用户通过直观的拖放方法构建控制算法框图，使用各种模块来制作所需的控制逻辑。</li>
		<li>构建完整的控制算法框图，如图 1 所示，并按照下述步骤操作。</li>
		<li>从左侧的设备型号中选择 双倒摆系统模块 。</li>
		<li>选择 增益模块 来设计线性二次稳压器 （LQR） 控制器的反馈矩阵。</li>
		<li>选择 阶跃信号 作为输入并添加其他模块。双击模块可查看详细信息并修改参数配置。例如，双击“ 恒定信号模块 ”可修改恒定信号的值。</li>
	</ol></li>
	<li>完成控制算法设计后，单击 “开始仿真 ”按钮。仿真完成后，观察所设计算法的控制效果。如果对仿真结果不满意，请微调 LQR 控制器的参数，直到获得性能更高的控制算法。</li>
	<li>单击 “编译 ”按钮以生成控制算法。算法编译完成后，存储在实验算法子页面和算法设计子页面的私有算法区域。</li>
	<li>单击位于控制算法部分右侧的 “下载算法 ”按钮，在实验算法子页面上下载控制算法。</li>
	<li>选择实验配置，在 “监控配置 ”子页面进行实验。系统提供预定义的配置，满足用户的一般实验需求。 注：用户可以灵活地单击“ 创建新监测仪 ”按钮，以根据其特定的实验需求定制监测设置。</li>
	<li>自定义监控配置，并从监控配置子页面的编辑界面中选择各种可用的组件，如图 2 所示。这些组件包括输入变量组件、输出变量曲线显示组件和 3D 模型组件。</li>
	<li>对于 VR 实验，请选择 3D 模型组件。3D 模型组件允许用户将 3D 模型集成到监控配置中。</li>
	<li>为了方便参数配置，请调整每个组件的参数，这些参数直接链接到系统参数变量。双击组件并访问窗口以在实验系统中选择相关的可选参数。</li>
	<li>用户可以灵活地通过调整组件大小来优化监控配置的布局。为此，请将相应组件的边缘拖动到所需的尺寸。</li>
	<li>点击“ 保存”按钮 ，可保存设计的监测配置，以备后续实验使用，节省了重复设置监测系统的时间和精力。 注意： 只有在正确下载控制算法后，才能执行监控配置。</li>
	<li>单击窗口中的“ 开始实验 ”按钮以启动实验。单击 3D 模型组件右下角的 VR 按钮 以启动 VR 实验。 注意：VR 实验嵌入在网页上。当用户首次使用时，浏览器可能会在左上角提示他们允许浏览器使用 VR 功能，选择 允许 继续。</li>
</ol>2. 选择访问方式
<ol><li>使用 WebVR 模拟器扩展。要使用此方法进行实验，请安装 WebVR 模拟器扩展，该扩展程序可从浏览器的扩展商店中轻松搜索和下载。 注意：WebVR 模拟器扩展可帮助用户在 Web 浏览器中运行 WebVR 内容，并提供虚拟 VR 耳机和手柄控制器环境，而无需使用真实的 VR 设备。</li>
	<li>使用支持 WebVR 的 VR 设备。如果是首次使用VR设备，则需要进行基本的环境配置。首先，打开耳机和控制器的电源以启动系统。在耳机中设置初始 ROOM 程序。按照耳机屏幕上显示的视觉提示，使用手柄控制器仔细校准虚拟空间环境的边界和方向。最后，在耳机和计算机之间建立流媒体连接。 注意：这是访问建议系统的第二种方法。VR 设备通常包括一个耳机和一对手柄控制器。VR 设备具有内置商店，用户可以在其中下载支持 WebVR 的浏览器。或者，用户可以使用内置浏览器，该浏览器通常支持WebVR。值得注意的是，各种 VR 设备可能会采用不同的连接方法。</li>
</ol>3.实验步骤
<ol><li>调整透视以找到进行双倒摆系统实验的最佳位置。<ol><li>对于使用 WebVR 仿真器扩展的用户，打开 开发人员工具，找到 WebVR 扩展，然后使用鼠标操作虚拟 VR 设备来调整视角，如图 3 所示。</li>
		<li>对于使用虚拟设备的用户，可以沉浸在虚拟实验环境中，并通过物理动作确定最佳实验位置。</li>
	</ol></li>
	<li>如下所述，使用手柄控制器与双倒摆系统进行交互。<ol><li>将手柄移近立方体。按下 触发 按钮捡起立方体，双倒立方体系统将停止移动。</li>
		<li>通过移动手柄，控制立方体的位置。一旦立方体处于所需位置，通过松开触发按钮来释放立方体。该位置现在被指定为推车的后续设定点， 如图 3 所示。</li>
	</ol></li>
	<li>观察双倒摆系统的运动过程。通过操纵交流电 （AC） 伺服电机，使皮带运动。在皮带的推动下，倒立摆可以沿着导轨移动，双倒摆的系统结构如图 4所示。最终，双倒立摆将稳定在设定点。</li>
	<li>鼓励用户迭代地操纵立方体的位置，不断调整推车的设定点，并仔细观察双倒摆系统的动态行为。</li>
</ol>

基于 WebVR 的虚拟现实实验室系统，用于沉浸式在线实验

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作者没有什么可透露的。

所提出的协议描述了一种虚拟实验室系统，该系统使用户能够在线进行VR实验，而且还使用低成本的PC控制器28，这有利于大规模应用推广。用户可以获得关于整个实验过程的知识，从原理和算法到实际的实验操作。该系统允许用户沉浸在实验中，消除了对传统鼠标和键盘输入的依赖。该系统为观察实验过程和动手操作实验设备提供了身临其境的体验。
该系统超越了传统的界面，为用户提供了一种更直观、更吸引人的方式来与实验设备进行交互。与物理实验室中的动手实验类似，该虚拟实验室致力于尽可能忠实地再现实验操作。这种在线访问方法为虚拟实验室提供了以下优势。
灵活性和便利性：用户可以通过网络浏览器随时随地访问虚拟实验室，而不受特定物理实验室位置和时间表的限制。这种方法大大增强了远程学习的便利性2.
可扩展性和成本效益：虚拟实验室可以轻松扩展并提供额外的计算资源和实验设备，以满足大规模应用的需求。用户无需自己购买和维护昂贵的硬件设备，而是可以使用基于 Web 的资源进行实验，从而减少成本投资3.
安全性：虚拟实验室可以提供增强的安全措施。用户无需担心实验过程中因操作不当而导致事故，这在一定程度上有助于确保用户的安全29.
通过利用VR技术，用户可以进入一个模拟的实验室环境，在那里他们可以与物体互动，并使用手柄进行实验，类似于物理实验室。 如图 3 所示，用户可以使用手柄拾取和移动立方体，以在双倒摆系统中为推车设置设定值。这种互动形式不仅为虚拟实验室体验增加了新的真实感和互动性，而且增强了用户对实验的理解。
此外，该系统还为用户提供了探索实验的机会。他们可以设计自己的控制算法，观察不同控制参数的影响，这有助于他们更深入地理解实验原理30。它培养了用户的参与意识和主动学习意识。 
目前，VR实验室主要针对特定场景进行设计和使用，缺乏大规模应用的框架。用户通常只能根据预定义的步骤进行实验，而实现自己想法的机会有限。相比之下，基于 WebVR 的虚拟实验室将实验内容作为组件模块无缝集成到虚拟实验室中。这种方法不仅用途广泛，适用于广泛的应用框架，而且还使用户能够与实验设备进行交互，并根据自己的喜好和需求进行定制实验。 
尽管如此，某些问题仍值得关注和解决。其中包括需要更广泛的虚拟资源库，以及与物理设备相比，在模拟虚拟设备的动态行为时需要提高精度。我们计划通过与不同领域的主题专家合作来扩展我们的虚拟资源库，这将确保我们涵盖从自然科学到工程学的广泛实验内容，以满足不同用户的需求。此外，我们鼓励用户积极参与到我们系统的建设中来。除了为仓库提供建议外，我们还计划在未来进行用户调查和访谈，以更深入地了解用户期望的资源类型和领域。为了解决仿真动态行为的精度挑战，使用先进的建模技术，例如基于机器学习的方法或更复杂的数学模型，以提高虚拟设备表示的精度。此外，现实世界的系统通常具有不确定性，需要将其纳入虚拟设备仿真方法中，同时保持准确性，从而实现更真实的现实世界表示。
综上所述，所提出的虚拟实验室系统使用户能够以沉浸式和互动的方式参与虚拟现实实验。通过提供尽可能真实的实验体验，它增强了用户对实验过程的理解，从原理和设计到实验操作。该系统的在线可访问性也提供了一个灵活、便捷、安全的实验环境，使其成为大规模科学研究和教育培训的有前途的解决方案。

随着互联网的进步和移动设备的普及，对在线教育的需求越来越大1.特别是在疫情肆虐的时期，传统教育机构在有效开展面对面教学方面往往面临挑战，这凸显了在线教育作为一种重要的教学方法的重要性2.理论课程相对容易转移到在线平台。这些课程可以借助远程视频会议软件和大规模开放在线课程 （MOOC）3 等工具进行。然而，实践课程面临着更大的挑战，因为它们要求用户在传统实验室中进行动手实验。
研究人员在解决在线提供实验设备的挑战方面做出了重大贡献。在过去的二十年中，对在线实验室的概念和技术进行了广泛的研究 4,5.在线实验室通常包括远程实验室6、虚拟实验室7 和混合实验室8。这些在线实验室方法已在各种工程学科中得到广泛应用，包括控制工程9、机械工程10 和软件工程11。
虽然在在线实验室实验操作的便利性方面取得了重大进展12 但用户仍然认为，与传统实验室环境相比，缺乏真实感和类似的动手实践操作，这影响了他们的整体体验13。这种用户体验的差异促使人们进一步开展研究和开发工作，以提高在线实验室环境中的真实感和参与度。
为了解决上述问题，虚拟现实（VR）技术已在虚拟实验室14 中得到应用，以提高虚拟实验室15的沉浸感和交互性。基于VR的虚拟实验室为用户提供了接近真实的实验体验。用户可以通过化身16 完成建筑教育过程中的小组作业，像在传统课堂环境中一样，身临其境地一起执行建筑测量过程。此外，基于虚拟现实的虚拟实验室允许用户通过佩戴虚拟实验室头盔和手柄17进入虚拟实验室的沉浸式环境，与虚拟实验设备进行交互，提高了用户的动手能力18。对于不同的教育目的，我们可以设计不同的虚拟环境。例如，虚拟现实可以与游戏化理论相结合，以加强对公众的工程教育，并提高传播可持续发展等难以理解的知识的效率19.
与在线实验室，特别是虚拟实验室类似，基于WebVR的虚拟实验室具有许多优势。首先，它们突破了传统实验室的时间和空间限制，用户可以随时随地进行实验20。其次，在线实验室可以提供更安全的实验环境，避免实验操作中可能出现的危险和事故21.第三，虚拟实验室还可以提供更多的实验资源和模拟情境，以扩展用户的实验范围和体验22.最重要的是，基于WebVR的虚拟实验室可以激发用户的学习兴趣和主动性，增强他们的实验体验和参与度23.
与其他基于VR的虚拟实验室相比，基于WebVR的虚拟实验室将基于VR的虚拟实验室与基于Web的在线实验室的优点无缝结合。现实中的虚拟仪器系统 （VISIR）24 通过构建真实电路板来构建基本的模拟电子远程实验室。用户可以在Web界面上进行模拟实验，完成真实的电路板实验。Weblab-Deusto8 构建了水箱现场可编程门阵列 （FPGA） 实验室，用户可以在 Web 平台中与水箱的三维 （3D） 模型进行交互，而无需依赖其他插件。本文提出的系统引入了将WebVR作为模块化组件无缝集成到现有虚拟实验室基础设施中的能力。这种集成可以在不破坏实验室原有建筑框架的情况下实现，从而保留了实验室的基本结构和功能。这种集成也适用于具有独立前端和后端的在线实验室框架。
本文提出的系统基于网络化控制系统实验室（NCSLab）25实现，继承了NCSLab系统的灵活性、交互性、模块化和跨平台特性。用户可以根据不同的模块进行实验，也可以定制算法和配置接口，为用户提供足够的自我实现空间。在线实验是根据用户运行的算法实时驱动的。用户可以在进行VR实验时，与虚拟模型进行交互，改变实验算法的输入，甚至可以通过组件改变控制算法的参数，使用户更真实地体验控制算法的原理。
基于WebVR的虚拟实验室为在线教育带来了巨大的潜力。它可以提供身临其境的实验体验，克服传统实验室的局限性，促进用户的动手实践技能和创新思维。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>3DS Max</td>
			<td>Autodesk</td>
			<td></td>
			<td>3ds Max professional 3D modeling, rendering, and animation software enables you to create expansive worlds and premium designs. 
			https://www.autodesk.com/ca-en/products/3ds-max/overview</td>
		</tr>
		<tr>
			<td>Meta Quest 2</td>
			<td>Meta Platforms</td>
			<td>10036728220341</td>
			<td>meta quest 2 is a standalone virtual reality headset that allows users to experience WebVR content. 
			https://www.meta.com/it/quest/products/quest-2/</td>
		</tr>
		<tr>
			<td>Unity</td>
			<td>Unity Technologies</td>
			<td></td>
			<td>Unity is the platform for real-time 3D interactive content creation and operation. 
			All creators, including game developers, artists, architects, automotive designers, film and television, use Unity to bring their ideas to life. 
			The Unity platform offers a complete suite of software solutions for creating, operating, and realizing any real-time interactive 2D and 3D content 
			on cell phones, tablets, PCs, game consoles, augmented reality, and virtual reality devices. 
			https://unity.com/cn</td>
		</tr>
	</tbody>
</table>

online virtual reality networked control laboratory applied in control engineering education

在线实验室在工程教育中发挥着重要作用。这项工作讨论了一个基于WebVR的虚拟实验室系统。用户通过虚拟现实（VR）设备进入模拟实验室环境，并与实验设备进行交互，类似于物理实验室中的动手实验。此外，所提出的系统允许用户设计自己的控制算法，并观察不同控制参数的影响，以增强他们对实验的理解。为了说明所提出的虚拟实验室的特点，本文提供了一个例子，即在双倒摆系统上的实验。实验结果表明，所提系统允许用户以沉浸式和交互的方式进行实验，为用户提供了从主体设计到实验操作的完整实验过程。此外，还提供了一种解决方案，可以将任何虚拟实验室转变为基于WebVR的虚拟实验室，以进行教育和培训。

所提出的VR实验系统为用户提供了使用VR设备进行沉浸式实验的能力，从而增强了用户与实验设备之间的交互。此外，该系统是基于网络的，用户无需配置本地环境。这种设计允许系统的可扩展性，使其适用于大规模应用以及培训和教育目的。
在传统的实验室环境中，用户需要亲自配置和安装软件和硬件设备，这会消耗大量的时间和资源26.然而，虚拟实验室利用云计算和虚拟化技术将实验室环境迁移到云端。用户只需通过网络浏览器访问相应的网站，即可使用实验室提供的功能和资源。
图 3 展示了用户可以使用不同的方法进行 WebVR 实验。没有现成的 VR 设备的用户可以通过浏览器扩展快速进行实验。能够使用VR设备的用户可以沉浸在实验中，并直接与实验设备互动，从而增强了探索实验过程的真实感。这两种不同的WebVR实验方式为用户提供了更多的选择，并使更广泛的用户能够使用所提出的系统。
双倒摆示例表明，所提出的基于WebVR的虚拟实验室可以直接在Web浏览器中运行，而无需额外的软件安装或配置。这种方法不仅减少了用户的不便，而且大大增强了系统的可扩展性。此外，用户可以选择使用VR设备与实验设备进行身临其境的交互。通过使用手柄控制器来调整系统参数，用户不仅可以增强他们的动手经验，还可以提高他们的理论知识和实践技能。
共有 21 名学生参与了实验，并进行了问卷调查，以进一步验证所提系统的适用性和有效性。我们纳入了具有自动化和控制工程背景的学生，这些学生之前都参加过NCSLab的虚拟实验，对虚拟实验有一些基本的了解，但没有参加过基于WebVR的NCSLab的VR实验。通过采用匿名统计数据，我们保证了参与者在填写问卷时的隐私和安全，从而保证了问卷数据的可靠性。
问卷调查结果 如图5所示，数据表明，本文提出的系统在真实感和与设备的交互性方面表现良好，与传统的鼠标-键盘虚拟实验相比，取得了显著的提升。此外，参与者的反馈显示，该系统不仅提高了学生的学习兴趣和实验技能，而且帮助他们更好地理解实验内容，从而提升了学习成果。
值得注意的是，大多数学生认为，这种类型的实验不仅适用于当前的课程和实验，而且具有在其他课程和实验中应用的潜力。
本文提出的系统使用3DS Max软件对实验设备进行建模，使用Unity引擎软件27 对实验场景进行渲染，并允许用户使用VR设备与设备进行交互。最后，将实验场景打包成Web图形库（WebGL）格式，并以模块化组件的形式无缝集成到在线实验室系统中，构建基于WebVR的虚拟实验室系统。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/66432/66432fig01.jpg"> 图 1：双倒立摆系统的控制算法设计。 用户可以从左侧的模块库中选择不同的模块来构建双倒摆系统的控制算法。模块的选择和连接与MATLAB/Simulink中的模块类似。在双倒摆系统领域，大量的控制方法比比皆是。对于本系统，选择的策略是线性二次稳压器（LQR）控制方法，该图显示了根据LQR控制器构建的反馈矩阵。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66432/66432fig01large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/66432/66432fig02.jpg"> 图 2：用于监控双倒立摆系统的配置设计。 用户可以从上面的组件库中选择组件来设计监控配置。如果需要进行 VR 实验，则必须选择 3D 模型组件。用户可以灵活地选择图表组件来直观地跟踪双倒摆的角度方向和位置的变化，或者选择输入组件来调整控制器参数。双击该组件允许用户在系统变量之间建立关联以进行参数配置。在双倒摆系统中，图表的参数配置为包含购物车的设定位置和实际位置，以及一阶和双摆的角度。监控配置设计完成后，用户应首先点击“ 开始实验 ”按钮激活实验。在此之后，他们可以通过单击位于 3D 模型组件右下角的 VR 按钮来启动 VR 实验。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66432/66432fig02large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/66432/66432fig03.jpg"> 图 3：使用 VR 头戴式设备和 WebVR 仿真器扩展进行双倒摆系统实验。 用户可以通过 VR 设备或 WebVR 模拟器扩展进行 WebVR 实验。使用手柄控制立方体以设置双倒摆的设定点。一旦确定了立方体的位置，双倒立摆将稳步地向设定点方向移动，直到它最终稳定在设定位置。在 3D 模型的右侧是一张图表，记录了购物车的位置以及一阶摆和双摆的角度。该图表还允许观察关键系统参数的变化趋势。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66432/66432fig03large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/66432/66432fig04.jpg"> 图 4：双倒摆系统的结构。 底座上方有一个立方体，立方体的位置就是购物车的设定点。用户可以拿起立方体并通过手柄调整位置。一旦交流 （AC） 伺服电机推动皮带旋转，推车将在皮带的推动下沿着导轨前进。与这个运动配合的是，一阶摆锤和双摆锤也将经历相应的位移和旋转。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66432/66432fig04large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/66432/66432fig05.jpg"> 图5：调查问卷的数据结果。 调查问卷由六个问题组成，每个问题都在这里进行了详细的详细说明。每个问题有五个选项，大致表示非常不同意、不同意、中立、同意和非常同意，等级为 1 到 5。共收集到21份有效回复。平均值和标准差是根据这些分数计算得出的，并在图中以图形方式呈现，以便清晰和解释。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66432/66432fig05large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>

Read this Scientific Article Protocol about Enhancing Engineering Education via WebVR-Based Online Laboratories at JoVE.com

作者聚焦：通过基于 WebVR 的在线实验室增强工程教育

本研究描述了一种基于 WebVR 的在线虚拟现实 （VR） 实验室系统，该系统为用户提供了由 VR 设备支持的沉浸式和交互式实验功能。所提出的系统不仅有助于提高用户在线实验参与的真实感，而且适用于广泛的在线实验室框架。

在线虚拟现实网络化控制实验室在控制工程教育中的应用 

Online laboratories play an important role in engineering education. This work discusses a WebVR-based virtual laboratory system. The user enters the ...

本文的研究范围侧重于基于网络虚拟现实的在线实验室在工程教育中的应用。本文试图回答的问题是，提案系统是否能够依赖用户通过VR设备进行基于Web的实验，从而增强在线实验的沉浸感和整个活动。目前，用于促进这一研究领域的技术包括虚拟现实、增强现实和远程控制技术。本文提出的系统为用户提供了使用虚拟现实设备进行基于网络的沉浸式实验的能力，从而增强了用户与实验设备之间的交互。未来，我们将专注于基于VR的数字在线实验室。我们的目标是使用VR设备，通过虚拟设备的操作来控制物理设备。

online-virtual-reality-networked-control-laboratory-applied-control

Nanyang Technological University

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Online Virtual Reality Networked Control Laboratory Applied in Control Engineering Education

Design of Control Systems

SCIENTISTS IN ACTION

831 次观看.  Wuhan University. 本文的研究范围侧重于基于网络虚拟现实的在线实验室在工程教育中的应用。本文试图回答的问题是，提案系统是否能够依赖用户通过VR设备进行基于Web的实验，从而增强在线实验的沉浸感和整个活动。目前，用于促进这一研究领域的技术包括虚拟现实、增强现实和远程控制技术。本文提出的系统为用户提供了使用虚拟现实设备进行基于网络的沉浸式实验的能力，从而?...

视频: 作者聚焦：通过基于 WebVR 的在线实验室增强工程教育

Free-form Light Actuators &#8212; Fabrication and Control of Actuation in Microscopic Scale

Liquid crystalline elastomers (LCEs) are smart materials capable of reversible shape-change in response to external stimuli, and have attracted researchers&#39; attention in many fields. Most of the studies focused on macroscopic LCE structures (films, fibers) and their miniaturization is still in its infancy. Recently developed lithography techniques, e.g., mask exposure and replica molding, only allow for creating 2D structures on LCE thin films. Direct laser writing (DLW) opens access to truly 3D fabrication in the microscopic scale. However, controlling the actuation topology and dynamics at the same length scale remains a challenge.
In this paper we report on a method to control the liquid crystal (LC) molecular alignment in the LCE microstructures of arbitrary three-dimensional shape. This was made possible by a combination of direct laser writing for both the LCE structures as well as for micrograting patterns inducing local LC alignment. Several types of grating patterns were used to introduce different LC alignments, which can be subsequently patterned into the LCE structures. This protocol allows one to obtain LCE microstructures with engineered alignments able to perform multiple opto-mechanical actuation, thus being capable of multiple functionalities. Applications can be foreseen in the fields of tunable photonics, micro-robotics, lab-on-chip technology and others.

Here, we fabricate 3D polymeric micro/nano structures in which both the shape and the molecular alignment can be engineered with nanometer scale accuracy by the use of direct laser writing. Light induced deformation of several types of liquid crystalline elastomer microstructures can be controlled in the microscopic scale.

自由形式的光驱动器 - 制作和开动控制在微观尺度

Liquid crystalline elastomers (LCEs) are smart materials capable of reversible shape-change in response to external stimuli, and have attracted ...

科研

工程学

Hand Controlled Manipulation of Single Molecules via a Scanning Probe Microscope with a 3D Virtual Reality Interface

Considering organic molecules as the functional building blocks of future nanoscale technology, the question of how to arrange and assemble such building blocks in a bottom-up approach is still open. The scanning probe microscope (SPM) could be a tool of choice; however, SPM-based manipulation was until recently limited to two dimensions (2D). Binding the SPM tip to a molecule at a well-defined position opens an opportunity of controlled manipulation in 3D space. Unfortunately, 3D manipulation is largely incompatible with the typical 2D-paradigm of viewing and generating SPM data on a computer. For intuitive and efficient manipulation we therefore couple a low-temperature non-contact atomic force/scanning tunneling microscope (LT NC-AFM/STM) to a motion capture system and fully immersive virtual reality goggles. This setup permits &#34;hand controlled manipulation&#34; (HCM), in which the SPM tip is moved according to the motion of the experimenter&#39;s hand, while the tip trajectories as well as the response of the SPM junction are visualized in 3D. HCM paves the way to the development of complex manipulation protocols, potentially leading to a better fundamental understanding of nanoscale interactions acting between molecules on surfaces. Here we describe the setup and the steps needed to achieve successful hand-controlled molecular manipulation within the virtual reality environment.

We demonstrate the precise manipulation of individual organic molecules on a metal surface with the tip of a scanning probe microscope driven in 3D by the experimenter's hand using a motion capture system and fully immersive virtual reality goggles.

通过手扫描探针显微镜用三维虚拟现实接口控制单分子的操作

Considering organic molecules as the functional building blocks of future nanoscale technology, the question of how to arrange and assemble such building ...

Gain-compensation Methodology for a Sinusoidal Scan of a Galvanometer Mirror in Proportional-Integral-Differential Control Using Pre-emphasis Techniques

Galvanometer mirrors are used for optical applications such as target tracking, drawing, and scanning control because of their high speed and accuracy. However, the responsiveness of a galvanometer mirror is limited by its inertia; hence, the gain of a galvanometer mirror is reduced when the control path is steep. In this research, we propose a method to extend the corresponding frequency using a pre-emphasis technique to compensate for the gain reduction of galvanometer mirrors in sine-wave path tracking using proportional-integral-differential (PID) control. The pre-emphasis technique obtains an input value for a desired output value in advance. Applying this method to control the galvanometer mirror, the raw gain of a galvanometer mirror in each frequency and amplitude for sine-wave path tracking using a PID controller was calculated. Where PID control is not effective, maintaining a gain of 0 dB to improve the trajectory tracking accuracy, it is possible to expand the speed range in which a gain of 0 dB can be obtained without tuning the PID control parameters. However, if there is only one frequency, amplification is possible with a single pre-emphasis coefficient. Therefore, a sine wave is suitable for this technique, unlike triangular and sawtooth waves. Hence, we can adopt a pre-emphasis technique to configure the parameters in advance, and we need not prepare additional active control models and hardware. The parameters are updated immediately within the next cycle because of the open loop after the pre-emphasis coefficients are set. In other words, to regard the controller as a black box, we need to know only the input-to-output ratio, and detailed modeling is not required. This simplicity allows our system to be easily embedded in applications. Our method using the pre-emphasis technique for a motion-blur compensation system and the experiment conducted to evaluate the method are explained.

We propose a method to extend the corresponding frequency by using a pre-emphasis technique. This method compensates for the gain reduction of a galvanometer mirror in sine-wave path tracking using proportional-integral-differential control.

使用预加重技术增益补偿方法论电流镜的比例 - 积分 - 微分控制正弦扫描

Galvanometer mirrors are used for optical applications such as target tracking, drawing, and scanning control because of their high speed and accuracy. ...

Study of Siphon Breaker Experiment and Simulation for a Research Reactor

Under the design conditions of a research reactor, the siphon phenomenon induced by pipe rupture can cause continuous outward flow of water. To prevent this outflow, a control device is required. A siphon breaker is a type of safety device that can be utilized to control the loss of coolant water effectively.
To analyze the characteristics of siphon breaking, a real-scale experiment was conducted. From the results of the experiment, it was found that there are several design factors that affect the siphon breaking phenomenon. Therefore, there is a need to develop a theoretical model capable of predicting and analyzing the siphon breaking phenomenon under various design conditions. Using the experimental data, it was possible to formulate a theoretical model that accurately predicts the progress and the result of the siphon breaking phenomenon. The established theoretical model is based on fluid mechanics and incorporates the Chisholm model to analyze two-phase flow. From Bernoulli&#39;s equation, the velocity, quantity, undershooting height, water level, pressure, friction coefficient, and factors related to the two-phase flow could be obtained or calculated. Moreover, to utilize the model established in this study, a siphon breaker analysis and design program was developed. The simulation program operates on the theoretical model basis and returns the result as a graph. The user can confirm the possibility of the siphon breaking by checking the shape of the graph. Furthermore, saving the entire simulation result is possible and it can be used as a resource for analyzing the real siphon breaking system.
In conclusion, the user can confirm the status of the siphon breaking and design the siphon breaker system using the program developed in this study.

The siphon breaking phenomenon was investigated experimentally and a theoretical model was proposed. A simulation program based on the theoretical model was developed and the results of the simulation program were compared with experimental results. It was concluded that the results of the simulation program matched the experimental results well.

研究堆虹吸断路器试验与仿真研究

Under the design conditions of a research reactor, the siphon phenomenon induced by pipe rupture can cause continuous outward flow of water. To prevent ...

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

A method of carrier number control by electrolyte gating is demonstrated. We have obtained WS2 thin flakes with atomically flat surface via scotch tape method or individual WS2 nanotubes by dispersing the suspension of WS2 nanotubes. The selected samples have been fabricated into devices by the use of the electron beam lithography and electrolyte is put on the devices. We have characterized the electronic properties of the devices under applying the gate voltage. In the small gate voltage region, ions in the electrolyte are accumulated on the surface of the samples which leads to the large electric potential drop and resultant electrostatic carrier doping at the interface. Ambipolar transfer curve has been observed in this electrostatic doping region. When the gate voltage is further increased, we met another drastic increase of source-drain current which implies that ions are intercalated into layers of WS2 and electrochemical carrier doping is realized. In such electrochemical doping region, superconductivity has been observed. The focused technique provides a powerful strategy for achieving the electric-filed-induced quantum phase transition.

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

Here, we present a protocol to control the carrier number in solids by using the electrolyte.

用电解质浇注法对 WS2纳米器件电子态的电场控制

A method of carrier number control by electrolyte gating is demonstrated. We have obtained WS2 thin flakes with atomically flat surface via scotch tape ...

Generation and Coherent Control of Pulsed Quantum Frequency Combs

We present a method for the generation and coherent manipulation of pulsed quantum frequency combs. Until now, methods of preparing high-dimensional states on-chip in a practical way have remained elusive due to the increasing complexity of the quantum circuitry needed to prepare and process such states. Here, we outline how high-dimensional, frequency-bin entangled, two-photon states can be generated at a stable, high generation rate by using a nested-cavity, actively mode-locked excitation of a nonlinear micro-cavity. This technique is used to produce pulsed quantum frequency combs. Moreover, we present how the quantum states can be coherently manipulated using standard telecommunications components such as programmable filters and electro-optic modulators. In particular, we show in detail how to accomplish state characterization measurements such as density matrix reconstruction, coincidence detection, and single photon spectrum determination. The presented methods form an accessible, reconfigurable, and scalable foundation for complex high-dimensional state preparation and manipulation protocols in the frequency domain.

A protocol is presented for the practical generation and coherent manipulation of high-dimensional frequency-bin entangled photon states using integrated micro-cavities and standard telecommunications components, respectively.

脉冲量子频率梳的产生与相干控制

We present a method for the generation and coherent manipulation of pulsed quantum frequency combs. Until now, methods of preparing high-dimensional ...

Generation and Control of Electrohydrodynamic Flows in Aqueous Electrolyte Solutions

To drive electrohydrodynamic (EHD) flows in aqueous solutions, the separation of cation and anion transport pathways is essential because a directed electric body force has to be induced by ionic motions in liquid. On the other hand, positive and negative charges attract each other, and electroneutrality is maintained everywhere in equilibrium conditions. Furthermore, an increase in an applied voltage has to be suppressed to avoid water electrolysis, which causes the solutions to become unstable. Usually, EHD flows can be induced in non-aqueous solutions by applying extremely high voltages, such as tens of kV, to inject electrical charges. In this study, two methods are introduced to generate EHD flows induced by electrical charge separations in aqueous solutions, where two liquid phases are separated by an ion-exchange membrane. Due to a difference in the ionic mobility in the membrane, ion concentration polarization is induced between both sides of the membrane. In this study, we demonstrate two methods. (i) The relaxation of ion concentration gradients occurs via a flow channel that penetrates an ion-exchange membrane, where the transport of the slower species in the membrane selectively becomes dominant in the flow channel. This is a driving force to generate an EHD flow in the liquid. (ii) A long waiting time for the diffusion of ions passing through the ion-exchange membrane enables the generation of an ion-dragged flow by externally applying an electric field. Ions concentrated in a flow channel of a 1 x 1 mm2 cross-section determine the direction of the liquid flow, corresponding to the electrophoretic transport pathways. In both methods, the electric voltage difference required for an EHD flow generation is drastically reduced to near 2 V by rectifying the ion transport pathways.

The rectification of ion transport pathways is an effective method to generate one-directional ion-dragged electrohydrodynamic flows. By setting an ion-exchange membrane in a flow channel, an electrically polarized condition is generated and causes a liquid flow to be driven when an electric field is externally applied.

水电解质溶液中 Electrohydrodynamic 流的产生与控制

To drive electrohydrodynamic (EHD) flows in aqueous solutions, the separation of cation and anion transport pathways is essential because a directed ...

Radio Frequency Magnetron Sputtering of GdBa2Cu3O7&#8722;&#948;/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 (STO) Single-crystal Substrates

Here, we demonstrate a method of coating ferromagnetic La0.67Sr0.33MnO3 (LSMO) nanoparticles on (001) SrTiO3 (STO) single-crystal substrates by radio frequency (RF) magnetron sputtering. LSMO nanoparticles were deposited with diameters from 10 to 20 nm and heights between 20 and 50 nm. At the same time, (Gd) Ba2Cu3O7&#8722;&#948; ((Gd) BCO) films were fabricated on both undecorated and LSMO nanoparticle decorated STO substrates using RF magnetron sputtering. This report also describes the properties of GdBa2Cu3O7&#8722;&#948;/ La0.67Sr0.33MnO3 quasi-bilayer films structures (e.g., crystalline phase, morphology, chemical composition); magnetization, magneto-transport, and superconducting transport properties were also evaluated.

Radio Frequency Magnetron Sputtering of GdBa2Cu3O7ÃƒÆ’Ã‚Â¢Ãƒâ€¹Ã¢â‚¬Â 'ÃƒÆ’Ã…Â½ Â´/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 STO Single-crystal Substrates

Here, we present a protocol to grow LSMO nanoparticles and (Gd) BCO films on (001) SrTiO3 (STO) single-crystal substrates by radio frequency (RF)-sputtering.

Gdba2cu 3 o7 的射频磁控管散射-/la0.67sr 0.67 mno 3 准双层薄膜上的 srtio 3 (sto) 单晶基板上

Here, we demonstrate a method of coating ferromagnetic La0.67Sr0.33MnO3 (LSMO) nanoparticles on (001) SrTiO3 (STO) single-crystal substrates by radio ...

A 100 KW Class Applied-field Magnetoplasmadynamic Thruster

Applied-field magnetoplasmadynamic thrusters (AF-MPD thrusters) are hybrid accelerators in which electromagnetic and gas dynamic processes accelerate plasma to high speed; they have considerable potential for future space applications with the significant advantages of high specific impulse and thrust density. In this paper, we present a series of protocols for designing and manufacturing a 100 kW class of AF-MPD thruster with water-cooling structures, a 130 V maximum discharge voltage, a 800 A maximum discharge current, and a 0.25 T maximum strength of magnetic field. A hollow tantalum tungsten cathode acts as the only propellant inlet to inhibit the radial discharge, and it is positioned axially at the rear of the anode in order to relieve anode starvation. A cylindrical divergent copper anode is employed to decrease anode power deposition, where the length has been reduced to decrease the wall-plasma connecting area. Experiments utilized a vacuum system that can achieve a working vacuum of 0.01 Pa for a total propellant mass flow rate lower than 40 mg/s and a target thrust stand. The thruster tests were carried out to measure the effects of the working parameters such as propellant flow rates, the discharge current, and the strength of applied magnetic field on the performance and to allow appropriate analysis. The thruster could be operated continuously for significant periods of time with little erosion on the hollow cathode surface. The maximum power of the thruster is 100 kW, and the performance of this water-cooled configuration is comparable with that of thrusters reported in the literature.

The goal of this protocol is to introduce the design of a 100 kW class applied-field magnetoplasmadynamic thruster and relevant experimental methods.

一个100千瓦级的应用场磁等离子体动力学推进器

Applied-field magnetoplasmadynamic thrusters (AF-MPD thrusters) are hybrid accelerators in which electromagnetic and gas dynamic processes accelerate ...

O-cresol Concentration Online Measurement Based On Near Infrared Spectroscopy Via Partial Least Square Regression

Unlike macroscopic process variables, near-infrared spectroscopy provides process information at the molecular level and can significantly improve the prediction of the components in industrial processes. The ability to record spectra for solid and liquid samples without any pretreatment is advantageous and the method is widely used. However, the disadvantages of analyzing high-dimensional near-infrared spectral data include information redundancy and multicollinearity of the spectral data. Thus, we propose to use partial least squares regression method, which has traditionally been used to reduce the data dimensionality and eliminate the collinearity between the original features. We implement the method for predicting the o-cresol concentration during the production of polyphenylene ether. The proposed approach offers the following advantages over component regression prediction methods: 1) partial least squares regression solves the multicollinearity problem of the independent variables and effectively avoids overfitting, which occurs in a regression analysis due to the high correlation between the independent variables; 2) the use of the near-infrared spectra results in high accuracy because it is a non-destructive and non-polluting method to obtain information at microscopic and molecular scales.

The protocol describes a method of predicting o-cresol concentration during the production of polyphenylene ether using near-infrared spectroscopy and partial least squares regression. To describe the process more clearly and completely, an example of predicting the o-cresol concentration during the production of polyphenylene is used to clarify the steps.

O-cresol 浓度在线测量基于近红外光谱通过部分最小平方回归

Unlike macroscopic process variables, near-infrared spectroscopy provides process information at the molecular level and can significantly improve the ...