Coordination of human grasp and manipulation forces

项目总结 手复杂的神经肌肉系统使我们能够以无数种方式与世界互动， 其中之一就是灵巧的操作。然而，手令人难以置信的多功能性是有代价的：当 发生周围神经病、神经紊乱或创伤性损伤时，我们改善感觉运动的能力 我们对手的感觉运动控制机制的了解有限，严重挑战了我们的功能。 因此，提高对这些机制的认识可以提高临床干预的效果。 在过去的40年里，这一概念推动了广泛的研究，旨在解开手的 感应器运动控制机构工作。以前的研究已经提供了对 协调防止物体滑移所需的指位力。然而，令人惊讶的是，这项先前的工作被忽视了 为了解决操纵的另一个重要组成部分：控制对象位置和方向的能力， 也就是说，摆姿势。这是一个关键的差距，因为灵巧的操作通常既需要防止物体滑倒，也需要 对物体姿势的灵活控制。为了解决这一差距，在过去的十年里，我们的实验室开发了一种 实验范式，允许受试者选择抓住物体的位置，并包含灵巧性 部件，即在防止物体倾斜的同时将物体垂直举起。然而，最大的限制是 这项工作是，载荷和抓地力的调制不能分离，以确定它们的相对贡献 目标防滑和姿态控制。为了填补这一空白，我们提出了一种方法，使我们能够 第一，找出掌握和操纵背后的控制机制。我们的方法结合了 具有灵巧部件的任务、手指肌肉的表面肌电图术以及手指的新应用 为机器人操作开发的力分析。我们的任务要求受试者协调数字力量以 同时防止物体滑动，最大限度地减少物体倾斜。我们的分析可以在数学上将数字解耦 力分为抓地力(物体防滑)和操纵力(物体姿态控制)。我们将追求两个目标 目的：(1)确定抓握和操作力之间的因果关系；(2)量化握力和操纵力之间的因果关系 物体属性的可预测性对抓取力和操纵力协调的影响。如果 成功后，这一新知识将使临床医生能够提取关于手的状态的信息 感觉运动功能，否则无法通过临床评估工具提取。我们的长期目标 改进灵巧手法控制的理论结构并将其转化为临床 应用，包括量化临床干预后手功能恢复的工具，以及 辅助和/或康复设备的设计。

PROJECT SUMMARY The hand’s sophisticated neuromuscular system enables us to interact with the world in a myriad of ways, one of which is dexterous manipulation. The hand’s incredible versatility, however, comes at a cost: when peripheral neuropathies, neurological disorders or traumatic injury occur, our ability to improve sensorimotor function is severely challenged by our limited understanding of the hand’s sensorimotor control mechanisms. Therefore, improving our understanding of these mechanisms could enhance the impact of clinical intervention. This notion has driven extensive research over the past four decades aiming at unravelling how the hand’s sensorimotor control mechanisms operate. Previous research has provided significant insights into the coordination of digit forces required to prevent object slip. Surprisingly, however, this previous work neglected to address another important component of manipulation: the ability to control object position and orientation, i.e., pose. This is a critical gap because dexterous manipulation often requires both object slip prevention and dexterous control of object pose. To address this gap, in the past decade our laboratory has developed an experimental paradigm that allows subjects to choose where to grasp the object and contains a dexterity component, i.e., lifting an object straight while preventing it from tilting. Nevertheless, the major limitation of this work is that the modulation of load and grip forces cannot be decoupled to identify their relative contribution to object slip prevention and pose control. To fill this gap, we propose an approach that will allow us, for the first time, to identify the control mechanisms underlying grasp and manipulation. Our approach combines a task with a dexterity component, surface electromyography of digit muscles, and a novel application of digit force analysis developed for robotic manipulation. Our task requires subjects to coordinate digit forces to simultaneously prevent object slip and minimize object tilt. Our analysis can mathematically decouple digit forces into grasp force (object slip prevention) and manipulation force (object pose control). We will pursue two aims: (1) To determine the causal relation between grasp and manipulation forces, and (2) To quantify the effect of predictability of object properties on the coordination between grasp and manipulation forces. If successful, this new knowledge will enable clinicians to extract information about the state of the hand’s sensorimotor function that cannot otherwise be extracted by clinical assessment tools. Our long-term objective is to improve the theoretical constructs of dexterous manipulation control and their translation to clinical applications, including tools for quantifying recovery of hand function following clinical intervention, as well as design of assistive and/or rehabilitation devices.