Rinderknecht Mike Domenik, Delaloye Fabien André, Crespi Alessandro, Ronsse Renaud, Ijspeert Auke Jan
Biorobotics Laboratory; Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
IEEE Int Conf Rehabil Robot. 2011;2011:5975351. doi: 10.1109/ICORR.2011.5975351.
This paper provides a robustness analysis of the method we recently developed for rhythmic movement assistance using adaptive oscillators. An adaptive oscillator is a mathematical tool capable of extracting high-level features (i.e. amplitude, frequency, offset) of a quasi-sinusoidal measured movement, a rhythmic flexion-extension of the elbow in this case. By the use of a simple inverse dynamical model, the system can predict the torque produced by a human participant, such that a fraction of this estimated torque is fed back through a series elastic actuator to provide movement assistance. This paper objectives are twofold. First, we introduce a new 1 DOF assistive device developed in our lab. Second, we derive model-based predictions and conduct experimental validations to measure the variations in movement frequency as a function of the open parameters of the inverse dynamical model. As such, the paper provides an estimation of the robustness of our method due to model approximations. As main result, the paper reveals that the movement frequency is particularly robust to errors in the estimation of the damping coefficient. This is of high interest for the applicability of our approach, this parameter being in general the most difficult to identify.
本文对我们最近开发的使用自适应振荡器进行节律性运动辅助的方法进行了稳健性分析。自适应振荡器是一种数学工具，能够提取准正弦测量运动的高级特征（即幅度、频率、偏移），在这种情况下是肘部的节律性屈伸。通过使用简单的逆动力学模型，系统可以预测人类参与者产生的扭矩，使得该估计扭矩的一部分通过串联弹性致动器反馈以提供运动辅助。本文有两个目标。第一，我们介绍了我们实验室开发的一种新型单自由度辅助设备。第二，我们得出基于模型的预测并进行实验验证，以测量运动频率作为逆动力学模型开放参数的函数的变化。因此，本文提供了由于模型近似导致的我们方法稳健性的估计。作为主要结果，本文揭示了运动频率对阻尼系数估计中的误差特别稳健。这对于我们方法的适用性非常重要，因为该参数通常是最难识别的。
