Low-cost Tactile Sensing and Intelligent Reflexes for Prosthetic Hands

描述(申请人提供)：肌电假手使用者抓取和操纵易碎物体的能力严重受阻。在这些系统中，从截肢者的残馀肌肉记录的肌电(EMG)信号被处理以产生与肌肉激活成比例的电压，以驱动假手的直流马达。通过训练，用户可以通过对指尖速度的比例控制来自动打开、关闭和停止手。如果使用者施加连续的肌电信号来抓取物体，驱动指尖的电机将在物体上熄火，根据肌电幅度产生30-100N的高抓取力。如此大的力使得抓住易碎物体而不损坏它们非常具有挑战性。对肌电信号的仔细控制和计时可以用来以非常慢的速度移动手指，在脆弱的物体被压碎之前阻止它们；然而，这种方法需要直接的视觉、集中的注意力，而且成功与否参差不齐。因此，大多数假肢使用者避免处理易碎的物体，限制了假体的使用，特别是在双手任务中。在到目前为止的研究中，我们已经开发出了受生物启发的策略来解决这个问题。每个指尖上的触觉传感器都会检测到何时发生接触，并对马达的控制信号进行调制，类似于抑制性生物反射。对于低到中等幅度的肌电信号，这种反射将导致抓握闭合在较低的力下停止，防止脆弱的物体被压碎。这种方法不会限制受试者用更大的肌电信号产生更大的力以抓住较重的物体的能力，甚至如果这是预期的结果，也不会限制他们挤压物体的能力。这种方法为用户提供了对更大范围的抓取力的比例控制，几乎没有认知负担。初步研究表明，这一特征大大改善了涉及易碎或可变形物体的日常生活活动。在这项研究中，我们将开发一种低成本、坚固耐用的触觉传感器，满足商业合作伙伴提出的设计要求，并将这些传感器与商业上可用的假手集成在一起。将与第三方临床研究合作伙伴一起开发和评估评估该技术和替代技术的结果指标。这项研究和开发将集中在论证这项技术的可行性，并在商业化之前降低或消除风险。第一阶段终端将产生低成本的传感器，可用于更大规模的集成和临床试验，以证明UPS的好处 四肢截肢者、临床医生和第三方付款人。

DESCRIPTION (provided by applicant): Myoelectric prosthetic hand users are severely hampered in their ability to grasp and manipulate fragile objects. In these systems, electromyography (EMG) signals recorded from an amputee's residual muscles are processed to produce an electrical voltage proportional to muscle activation to drive the DC motors of a prosthetic hand. With training, users can voluntarily open, close and stop the hand with proportional control over the speed of the fingertips. If the user applies a continuous EMG signal to grasp an object, the motors driving the fingertips will stall on the object, producing high grasping forces of 30-100N depending on the EMG amplitude. Such high forces make it very challenging to grasp fragile objects without damaging them. Careful control and timing of EMG signals can be used to move the fingers at very slow speeds, stopping them before a fragile object is crushed; however, this approach requires direct vision, intense concentration, and has inconsistent success. As a result, most prosthesis users avoid handling fragile objects, restricting the utility of their prosthesis, particularly in bimanual tasks. In research to date, w have developed biologically inspired strategies to solve this problem. A tactile sensor on each fingertip detects when contact is made and modulates the control signals to the motors, similar to an inhibitory biological reflex. For a range of low to medium amplitude EMG signals, this reflex will cause the grasp closure to stop at low forces, preventing fragile objects from being crushed. This approach does not restrict a subject's ability to produce higher forces with larger EMG signals for grasping heavier objects, or even to crush objects if this is the desired outcome. This approach gives the user proportional control over a wider range of grasping forces with virtually no cognitive burden. Preliminary research has demonstrated that this feature offers substantial improvement in activities of daily living that involve fragile or deformable objects. In this research we will develop a low-cost and robust tactile sensor that meets design requirements proposed by a commercial partner and integrate these sensors with a commercially available prosthetic hand. Outcome measures to evaluate this and alternative technologies will be developed and evaluated with third-party clinical research partners. This research and development will focus on demonstrating feasibility of this technology and reducing or eliminating risks prior to commercialization. Phase I endpoints will result in a low-cost sensor ready for larger scale integration and clinical trials to demonstrate benefits to upper extremity amputees, clinicians and third-party payers.