Robust Cadence Tracking for Switched FES-Cycling With an Unknown Time-Varying Input Delay
Robust Cadence Tracking for Switched FES-Cycling With an Unknown Time-Varying Input Delay
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DOI：
10.1109/tcst.2021.3070189
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发表时间：
2021-04-08
影响因子：
4.8
通讯作者：
Dixon, Warren E.
中科院分区：
文献类型：
--
作者：
Allen, Brendon C.;Cousin, Christian A.;Dixon, Warren E.
对于受神经肌肉疾病（NC）影响的个体，功能性电刺激（FES）诱导的循环提供了一种功能恢复和治疗性运动的手段。尽管FES循环已被证明有许多好处，但实现协调运动的闭环FES控制存在挑战。例如，在施加（或去除）刺激和产生的肌肉力之间存在潜在的不稳定输入延迟。此外，在多个执行器（如FES或电机控制）之间切换也可能不稳定。本文简要介绍了延时相关的切换条件和鲁棒控制方法，以解释切换系统的未知时变输入延迟。一个李雅普诺夫类分析被执行，以产生半全局指数节奏跟踪到一个最终界。在6名健全参与者和4名nc参与者身上进行了实验，以验证所开发的控制器。所提出的控制器导致健全参与者的平均节奏误差为0.01 +/- 2.00转/分钟（RPM）， nc参与者的平均节奏误差为0.01 +/- 2.72转/分钟。
For an individual affected by a neuromuscular condition (NC), functional electrical stimulation (FES)-induced cycling provides a means of functional restoration and therapeutic exercise. Although FES-cycling has been shown to have numerous benefits, there are challenges to implementing closed-loop FES control for coordinated motion. For example, there exists a potentially destabilizing input delay between the application (or removal) of stimulation and the resulting muscle force. Moreover, switching between multiple actuators (such as FES or motor control) can also be destabilizing. This brief develops delay-dependent switching conditions and a robust control method to account for an unknown time-varying input delay of a switched system. A Lyapunov-like analysis is performed to yield semiglobal exponential cadence tracking to an ultimate bound. Experiments were performed on six able-bodied participants and four participants with NCs to validate the developed controller. The proposed controller resulted in an average cadence error of 0.01 +/- 2.00 revolutions per minute (RPM) for the able-bodied participants and 0.01 +/- 2.72 RPM for participants with NCs.