Flexible and stretchable force sensor for static and dynamic measurements (FlexFo)

力传感在自动化系统中提供触觉反馈方面发挥着关键的技术作用，从而最大限度地提高工业应用（即拾取机器人，机器人焊接）的效率，并使新设备和应用（即视频游戏控制器和智能家居）成为可能。现在，以人为本的技术（即电子和机器人皮肤、假肢、外科机械臂和康复设备、智能手机上的力敏按钮）正在成为日常生活中无处不在的一部分，对改进力传感器的需求是不言而喻的。模仿人类触觉感受器的传感器已经被开发出来。然而，现有的设备还不能满足柔性、可拉伸性、高力和空间分辨率、自供电以及静态和动态力测量的适应性等技术需求。因此，新形式的传感器是必不可少的，本研究计划旨在通过提出一种新的变革性设备来解决这一技术需求，该设备具有力敏感、柔性和可拉伸的材料，并嵌入整齐有序的纳米线（一种智能纳米复合材料）。这种智能纳米复合材料是用一种独特而创新的方法制成的，该方法包括在聚合物中填充有序排列的高纵横比纳米线（长度远大于宽度的明确几何形状）。这种方法与通常的保守方法（低纵横比纳米颗粒（不完美的球形）随机分散并分布到聚合物中）有本质上的区别。通过这种方式，以有序模式组织纳米线的变革策略将克服现有传感器的缺点和局限性，例如低面积/力/位置分辨率，有限的功能（测量静态或动态力）以及对不同应用的低适应性（柔性但不可拉伸）。纳米线固有的离散粒子特性和压电性质使传感器能够在电阻和压电功能的结合下工作，从而可以使用同一设备进行静态和动态力测量。该器件将以低直流偏置电压驱动（在“压电模式”下工作时低功耗和零功耗），并将提供模块化，灵活性和拉伸性，以实现最佳的表面一致性（即对各种系统和几何形状的适应性）。传感器原型将与市售传感器进行测试，并在不同弯曲条件下比较其力分辨率、灵活性、拉伸性和可靠性。总之，该研究计划有三个主要目标：创造一种结合了电阻和压电的智能纳米复合材料；使用智能纳米复合材料开发一种柔性和可拉伸的力传感器，用于静态和动态测量；并将开发的设备与市售传感器进行测试和比较。这项研究将有利于那些需要力传感的领域（静态、动态、冲击力测量）。第一个目标应用将包括将设备集成到机械臂中，以提供触觉反馈。然而，提出的开发智能纳米复合材料的方法将提高传感设备的性能，有可能彻底改变力传感市场，极大地改善当前的应用（即机器人），并瞄准新的应用，包括人体力传感（抓手，手/脚传感器），医疗保健和时尚智能服装，运动设备和小工具（目前仅限于位置或加速度传感）。

Force sensing plays a key technological role in providing tactile feedback in automated systems thus maximising efficiency in industrial applications (i.e., pick-and-place robots, robotic welding) and enabling novel devices and applications (i.e., video games controllers and smart homes). Now that human-oriented technologies (i.e., electronic and robotic skins, prosthetics, surgical robotic arms and rehabilitative devices, force-sensitive buttons on smartphones) are becoming a ubiquitous part of daily life, the requirement for improved force sensors is self-evident. Sensors that mimic human tactile receptors have been developed. However, the existing devices do not satisfy technological needs of flexibility, stretch-ability, high force and spatial resolution, self-powering and adaptability to measure both static and dynamic forces. Therefore, new forms of sensor are essential and this research programme aims to tackle this technological need by proposing a new transformative device featuring a force sensitive flexible and stretchable material with embedded well-aligned and ordered nanowires (a smart nanocomposite material). The smart nanocomposite is made using a unique and innovative approach that involves filling a polymer with well-ordered and aligned high aspect ratio nanowires (well-defined geometrical shape with length much greater than width). This approach differentiates substantially from the usual conservative methods where low aspect ratio nanoparticles (imperfect spherical shapes) are randomly dispersed and distributed into polymers. In this way, the transformative strategy of organising the nanowires in well-ordered patterns will overcome the disadvantages and limitations of present sensors such as low area/force/position resolution, limited functionality (measuring either static or dynamic forces) and low adaptability to different applications (flexible but not stretchable).The intrinsic discrete particle aspect and piezoelectric nature of the nanowires enables sensor operation in a combined resistive and piezoelectric functionality and thus enables both static and dynamics force measurements with the same device. The device will be driven with low DC bias voltage (low power consumption and zero-power when operating in "piezoelectric mode"), and will provide modularity, flexibility and stretch-ability for optimal surface conformability (i.e., adaptability to a wide range of systems and geometries). The sensor prototypes will be tested against commercially available sensors and their force resolution, flexibility, stretch-ability and reliability will be compared under different bending conditions. In summary, the research programme has three main objectives: to create a combined resistive and piezoelectric smart nanocomposite; use the smart nanocomposite to develop a flexible and stretchable force sensor for both static and dynamic measurements; and to test and compare the developed devices against commercially available sensors.The research will benefit those fields in which force sensing is needed (static, dynamic, impact force measurements). The first targeted application will involve integration of the devices into robotic arms to provide tactile feedback. However, the proposed approach of developing a smart nanocomposite that will enhance the performance of a sensing device has the potential to revolutionise the force sensing market, greatly improve current applications (i.e. robotics) and target novel applications including force sensing on humans (grippers, hands/feet sensors), smart clothes for healthcare and fashion, sports equipment and gadgets (currently limited solely to position or acceleration sensing).