Towards restoring natural touch for active prosthesis users: a Hands-on approach

人类的触觉对于我们探索和与环境互动的能力来说是极其宝贵的。虽然触觉感受器的基础是进化记录中最早的发现之一，但自那以后，它已经发展成一种复杂的多模式交互作用，几乎影响着我们所做的一切[1]。触摸媒介是一种探索、交流和支持的工具，对我们的健康发展和福祉是无价的[2，3]，手是感觉系统的主要参与者之一[4]。每只手大约有10,000条神经，至少有20种[5]，通过向大脑提供触觉反馈，我们可以掌握复杂的几何图形，操纵手中的小物体，甚至在黑暗的房间里找到一个电灯开关。然而，有很大一部分人没有能力做到这一点：据估计，目前有300多万截肢者生活在欧洲联盟，每年有4万人新截肢[6]。研究表明，这对个人的生活质量和心理健康有巨大的负面影响[7]。对于这些人来说，大多数商业假肢缺乏全面的反馈机制，无法向用户提供健全的人认为理所当然的信息。具有讽刺意味的是，与鲍登索假肢相比，主动假肢的驱动减少了能够传达给用户的触觉信息量[8]。这种取舍允许更高级的自主性和控制力，但通常会导致用户接受[9，10]和在抓取任务时性能下降，部分原因是缺乏感觉反馈[11]。因此，自然的、信息量丰富的触觉反馈将是上肢假肢装置的一个极大的好处。因此，为该项目提出的研究将旨在回答以下问题：“用于上肢假肢的集成触觉反馈机制的设计限制因素是什么，以实现抓取、精细操作和用户接受？”

The human sense of touch is incredibly valuable for our ability to explore and interact with our environment. While the basis for the touch receptors are among the earliest findings in the evolutionary record, it has since developed into a complex multimodal interaction that informs almost everything we do [1]. The medium of touch is an explorative, communicative, and supportive tool, that is invaluable to our healthy development and well-being [2,3], with the hand being one of the major players in the sensory system [4]. Roughly one hundred thousand nerves of at least twenty varieties innervate each hand [5] which, by providing tactile feedback to the brain, allows us to grasp complex geometries, manipulate small objects in the hand or even find a light switch in a dark room. However, there exists a large portion of the population who lack the ability to do this: it is estimated that there are currently upwards of three million amputees living in the European Union, with forty thousand new upper limb amputations per annum [6]. It has been shown that this has a massive negative impact on quality-of-life and mental health of the individual [7]. Most commercial prosthetics available to these people lack a comprehensive feedback mechanism that could supply the user with the information that able-bodied persons take for granted. Ironically, even, the drive towards active prosthetics has reduced the amount of tactile information able to be conveyed to the user, when compared to their Bowden-cable counterparts [8]. This trade-off has allowed for more advanced autonomy and control, but often leads to issues with user acceptance [9,10] and reduced performance in grasping tasks due, in part, to this lack of sensory feedback [11]. Thus, natural, informative tactile feedback would be a hugely beneficial addition to upper-limb prosthetic devices. As such the research proposed for this project will aim to answer the following question: "What are the design constraints of an integrated tactile feedback mechanism for upper limb prosthetics to enable grasping, fine manipulation and user acceptance?"