Abstract This paper proposed a multi-loop modulation method (MMM; 3M) on the servo drives applied for the lower limb rehabilitation exoskeleton (LLRE). This proposed 3M included the current, speed and position 3-loop with the auto-tuning, inertia identifier and external load torque observer. The controller gains by searching the optimal bandwidth and by identifying the inertia of the LLRE system were derived from the 3-loop auto-tuning. The controller gains could be instantly adjusted according to the system's oscillation during the LLRE gait motion. In particular, a concept of the phase margin (PM) was introduced in the calculation of the controller gain to ensure system stability. The proposed method could avoid system turbulence due to the excessive bandwidth. On the other hand, a torque observer and inertia identifier were adopted to compensate the external load. Compared the traditional parameter design method and traditional auto-tuning method with this proposed 3M in terms of tracking error and root mean square error (RMSE), the result showed that this proposed 3M provided better response and stability for gait tracking. Also, this proposed 3M could be adapted to variations in different loads.

中文翻译：

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下肢康复外骨骼伺服驱动多回路调制方法的研制

摘要 本文提出了一种应用于下肢康复外骨骼（LLRE）伺服驱动器的多回路调制方法（MMM；3M）。这个提议的 3M 包括电流、速度和位置 3 回路，具有自动调整、惯性标识符和外部负载扭矩观察器。控制器通过搜索最佳带宽和识别 LLRE 系统的惯性而获得的增益来自 3 环自动调整。控制器增益可以根据系统在 LLRE 步态运动期间的振荡进行即时调整。特别是在控制器增益的计算中引入了相位裕度 (PM) 的概念，以确保系统稳定性。所提出的方法可以避免由于带宽过大而引起的系统湍流。另一方面，采用转矩观测器和惯量识别器来补偿外部负载。在跟踪误差和均方根误差（RMSE）方面将传统的参数设计方法和传统的自动调整方法与所提出的 3M 进行比较，结果表明所提出的 3M 为步态跟踪提供了更好的响应和稳定性。此外，这个提议的 3M 可以适应不同负载的变化。