Hunt Kenneth J, Stone Barry, Negård Nils-Otto, Schauer Thomas, Fraser Matthew H, Cathcart Andrew J, Ferrario Chiara, Ward Susan A, Grant Stan
Centre for Rehabilitation Engineering, Department of Mechanical Engineering, University of Glasgow, Glasgow G12 8QQ, UK.
IEEE Trans Neural Syst Rehabil Eng. 2004 Mar;12(1):89-101. doi: 10.1109/TNSRE.2003.819955.
The aim of this study was to investigate feedback control strategies for integration of electric motor assist and functional electrical stimulation (FES) for paraplegic cycling, with particular focus on development of a testbed for exercise testing in FES cycling, in which both cycling cadence and workrate are simultaneously well controlled and contemporary physiological measures of exercise performance derived. A second aim was to investigate the possible benefits of the approach for mobile, recreational cycling.
A recumbent tricycle with an auxiliary electric motor is used, which is adapted for paraplegic users, and instrumented for stimulation control. We propose a novel integrated control strategy which simultaneously provides feedback control of leg power output (via automatic adjustment of stimulation intensity) and cycling cadence (via electric motor control). Both loops are designed using system identification and analytical (model-based) feedback design methods. Ventilatory and pulmonary gas exchange response profiles are derived using a portable system for real-time breath-by-breath acquisition.
We provide indicative results from one paraplegic subject in which a series of feedback-control tests illustrate accurate control of cycling cadence, leg power control, and external disturbance rejection. We also provide physiological response profiles from a submaximal exercise step test and a maximal incremental exercise test, as facilitated by the control strategy.
The integrated control strategy is effective in facilitating exercise testing under conditions of well-controlled cadence and power output. Our control approach significantly extends the achievable workrate range and enhances exercise-test sensitivity for FES cycling, thus allowing a more stringent characterization of physiological response profiles and estimation of key parameters of aerobic function. We further conclude that the control approach can significantly improve the overall performance of mobile recreational cycling.
本研究旨在探讨电动助力与功能性电刺激（FES）相结合用于截瘫患者骑行的反馈控制策略，特别关注开发一个用于FES骑行运动测试的试验台，在该试验台中，骑行节奏和功率输出能够同时得到良好控制，并能获取运动表现的当代生理指标。第二个目的是研究该方法对移动休闲骑行可能带来的益处。
使用一辆带有辅助电动马达的卧式三轮车，该车专为截瘫用户设计，并配备了用于刺激控制的仪器。我们提出了一种新颖的集成控制策略，该策略同时提供腿部功率输出的反馈控制（通过自动调整刺激强度）和骑行节奏的反馈控制（通过电动马达控制）。两个回路均采用系统辨识和基于模型的分析反馈设计方法进行设计。使用便携式系统实时逐次呼吸采集数据，得出通气和肺气体交换反应曲线。
我们给出了一名截瘫受试者的指示性结果，其中一系列反馈控制测试表明能够精确控制骑行节奏、腿部功率，并能抑制外部干扰。我们还给出了在控制策略辅助下的次最大运动台阶试验和最大递增运动试验的生理反应曲线。
集成控制策略在节奏和功率输出得到良好控制的条件下，有效地促进了运动测试。我们的控制方法显著扩展了可实现的功率输出范围，提高了FES骑行运动测试的灵敏度，从而能够更严格地描述生理反应曲线，并估算有氧功能的关键参数。我们进一步得出结论，该控制方法可显著提高移动休闲骑行的整体性能。
