Measurement and simulation of human-device interaction: application to lower-limb orthoses

在接下来的十年里，预计辅助人类运动的支架和动力外骨骼等设备将迅速增加。虽然被动式牙套已经使用了多年，一些外骨骼设备现在已经被批准上市，但设备设计师仍然不完全了解当前的设备是否安全有效，或者如何调整设备以达到不同个体的最佳性能。我的研究计划将解决这一领域的两个主要限制，广泛应用于辅助人类运动的设备。

Over the next decade, there is expected to be a rapid proliferation of devices, such as braces and powered exoskeletons, that assist human locomotion. While passive braces have been used for years, and some exoskeleton devices are now approved for market, device designers still don't fully understand whether current devices are safe and effective, or how devices should be tuned to achieve optimal performance for different individuals. My research program will address two primary limitations in this field, with broad applications for devices that assist human motion. First, we don't have adequate tools to measure and predict how external assistive devices interact with soft tissues of human limbs. When external devices apply forces to the body, there is significant deformation of underlying skin, muscle, and fat. This induces misalignment of device and human joint axes, which not only affects the efficiency of force transmission but also causes undesirable and uncomfortable shear loading of skin and other tissues. In the proposed research, we will develop simple, low-cost devices to measure tissue stiffness across an individual's limb, then create computational models to predict how assistive device design might be optimized for each individual. We will develop and validate this approach using a progression of experimental test cases, beginning with simple 1-DOF indentation and culminating in full 6-DOF interaction between the human lower-limb and instrumented orthoses (e.g. knee and ankle braces) with both passive springs and active actuator controls. Second, we lack adequate tools to predict how the human neuromuscular system will respond when external devices apply forces to assist locomotion. Since it is not generally feasible to measure the forces generated by human muscles, computational models are often used to estimate muscle forces. Yet, traditional models assume that muscular efforts are coordinated only to maximize endurance, and these models do not account for altered muscle coordination patterns seen in people with disabilities, or people using external devices. In the proposed research, we will explore novel simulation approaches to estimate muscle forces while accounting for the stabilizing effect of external devices. Our approach will use a weighted combination of competing objectives to minimize metabolic cost while achieving the desired joint stiffness at hip, knee, and ankle joints. Finally, it is anticipated that the experimental and computational tools developed in this research program will yield direct benefits for assistive device designers in both academia and industry. Leveraging our experimental and computational expertise, it will be feasible to test how current devices affect internal loading of soft tissues muscles, ligaments, and cartilage - in the human body. New collaborations will lead to the design of novel, more effective assistive devices.