Xiloyannis Michele, Annese Eugenio, Canesi Marco, Kodiyan Anil, Bicchi Antonio, Micera Silvestro, Ajoudani Arash, Masia Lorenzo
Robotics Research Centre, Interdisciplinary Graduate School, Nanyang Technological University, Singapore, Singapore.
Sensory-Motor Systems Lab, Department of Mechanical and Process Engineering, Institute of Robotics and Intelligent Systems, ETH Zürich, Zurich, Switzerland.
Front Neurorobot. 2019 Jun 18;13:39. doi: 10.3389/fnbot.2019.00039. eCollection 2019.
The size, weight, and power consumption of soft wearable robots rapidly scale with their number of active degrees of freedom. While various underactuation strategies have been proposed, most of them impose hard constrains on the kinetics and kinematics of the device. Here we propose a paradigm to independently control multiple degrees of freedom using a set of modular components, all tapping power from a single motor. Each module consists of three electromagnetic clutches, controlled to convert a constant unidirectional motion in an arbitrary output trajectory. We detail the design and functioning principle of each module and propose an approach to control the velocity and position of its output. The device is characterized in free space and under loading conditions. Finally, we test the performance of the proposed actuation scheme to drive a soft exosuit for the elbow joint, comparing it with the performance obtained using a traditional DC motor and an unpowered-exosuit condition. The exosuit powered by our novel scheme reduces the biological torque required to move by an average of 46.2%, compared to the unpowered condition, but negatively affects movement smoothness. When compared to a DC motor, using the our paradigm slightly deteriorates performance. Despite the technical limitations of the current design, the method proposed in this paper is a promising way to design more portable wearable robots.
软可穿戴机器人的尺寸、重量和功耗会随着其主动自由度的数量迅速增加。虽然已经提出了各种欠驱动策略，但其中大多数对设备的动力学和运动学都施加了严格的限制。在此，我们提出一种范式，使用一组模块化组件独立控制多个自由度，所有组件都从单个电机获取动力。每个模块由三个电磁离合器组成，通过控制电磁离合器将恒定的单向运动转换为任意的输出轨迹。我们详细介绍了每个模块的设计和工作原理，并提出了一种控制其输出速度和位置的方法。该设备在自由空间和负载条件下进行了特性表征。最后，我们测试了所提出的驱动方案驱动肘关节软外骨骼的性能，并将其与使用传统直流电机和无动力外骨骼条件下获得的性能进行比较。与无动力条件相比，由我们新颖方案驱动的外骨骼平均可将运动所需的生物扭矩降低46.2%，但对运动平滑度有负面影响。与直流电机相比，使用我们的范式会使性能略有下降。尽管当前设计存在技术限制，但本文提出的方法是设计更便携可穿戴机器人的一种有前景的方式。
