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Organic actuators for biomedical haptics and as tools for understanding the tactile sense

用于生物医学触觉的有机执行器以及作为理解触觉的工具

基本信息

批准号：
1929748
负责人：
Darren Lipomi
金额：
$ 39万
依托单位：
University of California-San Diego
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-09-01 至 2022-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1929748&HistoricalAwards=false
关键词：
Organic actuators biomedical haptics tools

项目摘要

The importance of the sense of touch in the medical sciences is nearly impossible to overstate. For example, palpation (examining by touching) is a first-line diagnostic tool in primary care, orthopedics, obstetrics, urology, oncology, and speech pathology. Moreover, touch is a key part of all procedures performed by hand--e.g., setting broken bones and dislocated joints, turning breech babies, and nearly all surgeries. For communities located in urban and rural "healthcare deserts," touch would greatly enhance the value of remote patient visits or drug-store-based diagnostic tests. Despite the attractiveness of virtual touch for remote care, medical training, and robot-assisted surgery, medical haptic technologies are underdeveloped. The reason is that existing systems cannot mimic the texture, softness, wetness, thermal conductivity, tack, and other near-surface properties of biological tissue. The key hypothesis of this project is that to mimic these sensations requires materials that can change their mechanical, electrical, and thermal properties in real time. The approach for doing so is to develop a system of haptic devices, i.e., devices that can stimulate the sense of touch, based on materials that can create sensations that can be transformed dynamically--e.g., rough vs. smooth, hot vs. cold, and sticky vs. slimy. Three types of devices are proposed based on (1) electricity conductive polymers to reproduce the feeling of fine texture, (2) arrays of liquid crystal elastomers that can change their softness in response to light, and (3) thermoplastics that can go from rubbery to stiff with small temperature changes to give the feeling of solidness and elasticity of virtual objects. Leveraging the flexible, wearable nature of these "haptic biomaterials," the investigators will build a prototype haptic glove that will allow a human user to differentiate between virtual objects by touch. By exploring the intersection of very different fields--organic materials and psychology--this project will provide a new toolkit for researchers to understand the tactile sense and mechanical sensing in biological systems more broadly. Research and education will be integrated through the following activities: (1) creation of internships for underrepresented minority students, (2) integration of the results into the investigators' graduate and undergraduate courses, and (3) creation of a video series on YouTube on the science of tactile perception and the results of this project which leverages considerable experience in creating scientific and educational videos.The long-term goal of this research is to use combinations of haptic devices that exploit multiple effects simultaneously to achieve sensations of hot and cold, hard and soft, rough and smooth, furry and scaly, or sticky and slimy. The focus of this project is on testing the hypothesis that actuators made from stimulus-responsive polymers--"organic actuators"--can supply new types of sensations for biomedical haptic devices unavailable to "off-the-shelf" components. Organic actuators are defined as structures made from polymeric materials whose oxidation state, electrical conductivity, phase behavior, molecular conformation, or packing structure can be altered by an electrical, optical, or thermal stimulus in real time to produce macroscopic effects. The Research Plan is organized under three tasks, each of which generates a tactile sensation using a different physical effect generated by an organic actuator. The FIRST Task is focused on electrical stimulation via spatially resolved electrotactile signals. A stretchable conductive polymer patterned into an array of electrodes generates an electrotactile signal that will be used to measure two-point resolution of stimulation and generate spatially resolved sensations. Studies are designed to test the hypothesis that the small size of the electrodes, along with the ability to address them individually in a purpose-designed multiplexed socket, can be used to produce sensations that translate in the x-y plane to give the sensation of motion. Human subject volunteers will be tested using a double-blind methodology. The SECOND Task is focused on optically-enabled mechanical stimulation created by a liquid-crystal elastomer (LCE) that undergoes a change in shape in response to light to generate sensations of variable softness, texture, and motion at the fingertip. One set of experiments is designed to measure softness thresholds that can be changed in real time by altering the elastic modulus of the LCE with the intensity of irradiation. A second set of experiments will use arrays of LCE microposts that can be moved with illumination to give human subjects the sense of feeling different textures and possibly the sensation of moving interfaces even as the fingertip maintains a fixed position. The THIRD Task is focused on providing thermally-enabled kinesthetic feedback via a thermoplastic polymer embedded into a textile glove. When heated or cooled just above or below its glass transition temperature, the glove will undergo a reversible change from stiff to soft to elicit a kinesthetic response. Control over the temperature of the glove can be achieved by pairing a thermistor that changes its resistance in response to thermal fluctuations, with the thermoelectric devices to stabilize the temperature and therefore the stiffness of the substrate. To achieve a human-machine interface, the glove has been fitted with flex sensors to control a robotic finger on whose tip there is a pressure sensor which, when activated, sends a signal to the thermoelectric devices in the glove to cool (stiffen the finger) and thus provide kinesthetic feedback to the user. Once the thresholds for stiffness required to generate a kinesthetic response are determined, the information gained will be used to design a game in virtual reality that asks participants to grasp objects that appear visually and identify which is solid and which is merely an image. Finally, textural information will be encoded in the solid objects to determine if it is possible for subjects to discriminate between objects by embedding haptic actuators of the type described in previous tasks.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

触觉在医学中的重要性怎么强调都不为过。例如，触诊（通过触摸进行检查）是初级保健、骨科、产科、泌尿科、肿瘤学和语言病理学中的一线诊断工具。此外，触摸是所有手工手术的关键部分——例如，固定骨折和脱臼的关节、翻转臀位婴儿以及几乎所有的手术。对于位于城市和农村“医疗沙漠”的社区来说，触摸将大大提高远程患者就诊或药店诊断测试的价值。尽管虚拟触摸对于远程护理、医疗培训和机器人辅助手术很有吸引力，但医疗触觉技术尚不发达。原因是现有系统无法模拟生物组织的质地、柔软度、湿度、导热性、粘性和其他近表面特性。该项目的关键假设是，要模仿这些感觉，需要能够实时改变其机械、电气和热性能的材料。这样做的方法是开发一个触觉设备系统，即可以刺激触觉的设备，其基础是可以产生动态变化感觉的材料，例如粗糙与光滑、热与冷、粘与粘。提出了三种类型的设备：(1) 导电聚合物，可再现细腻的质感；(2) 液晶弹性体阵列，可根据光线改变其柔软度；(3) 热塑性塑料，可在较小的温度变化下从橡胶状变为坚硬，从而赋予虚拟物体坚实和弹性的感觉。利用这些“触觉生物材料”的灵活、可穿戴特性，研究人员将构建一款触觉手套原型，允许人类用户通过触摸来区分虚拟物体。通过探索有机材料和心理学等不同领域的交叉点，该项目将为研究人员提供一个新的工具包，以更广泛地了解生物系统中的触觉和机械传感。研究和教育将通过以下活动进行整合：(1) 为代表性不足的少数族裔学生提供实习机会，(2) 将研究结果纳入研究人员的研究生和本科生课程中，以及 (3) 在 YouTube 上制作关于触觉感知科学和该项目成果的视频系列，该视频系列利用了制作科学和教育视频的丰富经验。这项研究的长期目标是结合使用触觉设备同时利用多种效果来实现热和冷、硬和软、粗糙和光滑、毛茸茸和鳞状或粘和粘的感觉。该项目的重点是测试这样的假设：由刺激响应聚合物制成的执行器（“有机执行器”）可以为生物医学触觉设备提供“现成”组件无法提供的新型感觉。有机致动器被定义为由聚合材料制成的结构，其氧化态、导电性、相行为、分子构象或堆积结构可以通过电、光或热刺激实时改变以产生宏观效应。该研究计划由三项任务组成，每项任务都利用有机执行器产生的不同物理效果产生触觉。第一个任务的重点是通过空间分辨的电触觉信号进行电刺激。形成电极阵列图案的可拉伸导电聚合物会产生电触觉信号，该信号将用于测量刺激的两点分辨率并产生空间分辨的感觉。研究旨在测试这样的假设：电极的小尺寸以及在专门设计的多路复用插座中单独寻址它们的能力可用于产生在 x-y 平面上平移的感觉，从而产生运动的感觉。人类受试者志愿者将使用双盲方法进行测试。第二项任务的重点是由液晶弹性体 (LCE) 产生的光学机械刺激，液晶弹性体会响应光而发生形状变化，从而在指尖产生不同的柔软度、纹理和运动感觉。一组实验旨在测量柔软度阈值，该阈值可以通过随照射强度改变 LCE 的弹性模量来实时改变。第二组实验将使用可在照明下移动的 LCE 微柱阵列，让人类受试者感受到不同的纹理，甚至在指尖保持固定位置时也可能感受到移动界面的感觉。第三项任务的重点是通过嵌入纺织手套中的热塑性聚合物提供热驱动的动觉反馈。当加热或冷却到略高于或低于其玻璃化转变温度时，手套将经历从硬到软的可逆变化，从而引起动觉反应。对手套温度的控制可以通过将热敏电阻与热电装置配对来实现，该热敏电阻响应于热波动而改变其电阻，以稳定温度并从而稳定基板的刚度。为了实现人机界面，手套配备了弯曲传感器来控制机器人手指，其尖端有一个压力传感器，当压力传感器被激活时，会向手套中的热电装置发送信号以冷却（使手指变硬），从而为用户提供动觉反馈。一旦确定了产生动觉反应所需的刚度阈值，获得的信息将用于设计虚拟现实中的游戏，要求参与者抓住视觉上出现的物体，并识别哪些是固体，哪些只是图像。最后，纹理信息将被编码在固体物体中，以确定受试者是否有可能通过嵌入先前任务中描述的类型的触觉执行器来区分物体。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。