A DISCUSSION OF PAST AND ONGOING WORK On the Design and Control of Highly Backdrivable Lower-Limb Exoskeletons
A DISCUSSION OF PAST AND ONGOING WORK On the Design and Control of Highly Backdrivable Lower-Limb Exoskeletons
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DOI：
10.1109/mcs.2018.2866605
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发表时间：
2018-12-01
影响因子：
5.7
通讯作者：
Gregg, Robert D.
中科院分区：
文献类型：
--
作者：
Lv, Ge;Zhu, Hanqi;Gregg, Robert D.
大多数辅助性外骨骼设计为使用高齿轮执行器严格跟踪基于时间的运动学模式，这阻止了用户在没有外骨骼帮助的情况下自由移动关节。具有部分或全部意志力控制其下肢的个体需要新的外骨骼设计和控制方法，以更好地与人类互动。为了帮助或增强人类的意志运动，外骨骼关节必须是可后驱动的，并且控制策略必须与用户的关节运动学保持不变。本文介绍了两代高度可后驱外骨骼背后的设计理念，这些外骨骼利用低传动比的扭矩密集型电机。为了利用这些设计，提出了一种基于扭矩的控制框架，该框架塑造了人体的动能和势能，以提供无轨迹辅助。通过对仿人两足动物的仿真，验证了不同能量整形控制策略的效果，并通过对膝关节-脚踝外骨骼的实验，证明了该控制方法的用户协作性和任务不变性。这些结果显示了步态辅助和增强的潜在价值，而不像传统的跑步机训练设备那样受到临床环境的限制。要实现控制设计和实现，需要线性代数、机器人动力学、状态空间控制和LabVIEW编程的知识。
The majority of assistive exoskeletons are designed to rigidly track time-based kinematic patterns using highly geared actuators, which prevents users from moving their joints freely without help from the exoskeleton. Individuals with partial or full volitional control of their lower extremities require novel design and control methods for exoskeletons that are more compatible with human interaction. To assist or augment volitional human motion, exoskeleton joints must be backdrivable, and the control strategy must be invariant to the user's joint kinematics. This article presents the design philosophy behind two generations of highly backdrivable exoskeletons, which utilize torque-dense motors with low-ratio transmissions. To leverage these designs, a torque-based control framework is presented that shapes the human body's kinetic and potential energies to provide trajectory-free assistance. Simulations with a human-like biped demonstrate the effects of different energy-shaping control strategies, and experiments with a powered knee-ankle exoskeleton show the user-cooperative and task-invariant nature of the control approach. These results exhibit potential value for gait assistance and augmentation without being constrained to a clinical environment like traditional treadmill training devices. To achieve the control design and implementation, knowledge of linear algebra, robot dynamics, state-space control, and LabVIEW programing is needed.