Magnetic Cogging Parallel-elastic Actuators for Energy-efficient Robotic Legs

该奖项探索了一种新的使能技术，用于敏捷、高效并安全地与人类互动的下一代机器人：磁齿槽平行弹性致动器(MC-PEA)。MC-PEA特别有希望用于机械腿，包括假肢、外骨骼以及诸如人形和四足动物等自主机器人的腿。MC-PEA包括一个与无源磁齿槽扭矩元件(CTE)并联的电机。MC-PEA的决定性特征是它具有一套离散的、可由设计控制的稳定平衡，这些平衡由强大的被动磁弹簧创建。电机不需要任何能量就可以简单地承受静态负载。相反，需要爆发的能量才能使CTE转向邻近的平衡状态。MC-PEA将有效地实现受生物启发的运动基元，包括多种共振模式，这些模式将导致行走和跑步所需的高效振荡运动。MC-PEA将代表着普遍存在的串联弹性致动器(SEA)的一种节能替代方案，在SEA是目前的首选解决方案的应用中。此外，该奖项将支持对研究生的培训和指导，将本科生纳入研究，并改进教学课程。该奖项的目标是描述磁齿槽平行弹性执行器(MC-PEA)的自然动力学和强迫动力学，并确定如何有效和高效地控制它以用于机器人运动。这项工作将提高对优化设计的MC-PEA在潜在参数变化时的性能规范的理解。MC-PEA的好处将通过在电动脚踝假体和腿部机器人中的应用来探索。该方法包括研究受生物启发的动态运动基元-包括阻抗控制、点对点子运动和振荡-使用带有简单的点状脚的两连杆机械腿，并使用MC-Peas为臀部和膝盖提供动力。这项研究还包括开发定制的能量再生电路，这种电路可以快速开启和关闭，以便在动态运动期间回收能量。项目成果将是各种步长的磁性齿槽扭矩元件(CTE)的最优参数设计，并将传播给机器人设计者。该项目由跨部门机器人基础研究计划支持，由工程总监(ENG)和计算机和信息科学与工程(CEISE)共同管理和资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award explores a novel enabling technology for next-generation robots that are agile, efficient, and that safely interact with humans: the magnetic cogging parallel-elastic actuator (MC-PEA). The MC-PEA is particularly promising for use in robotic legs, including prostheses, exoskeletons, and the legs of autonomous robots such as humanoids and quadrupeds. The MC-PEA comprises an electric motor connected in parallel with a passive magnetic cogging-torque element (CTE). The defining characteristic of the MC-PEA is that it has a discrete, controllable-by-design set of stable equilibria created by strong passive magnetic springs. No energy is required from the motor to simply hold a static load. Rather, bursts of energy are required to cause the CTE to cog over to a neighboring equilibrium. The MC-PEA will efficiently implement bioinspired motion primitives, including multiple resonance modes that will lead to efficient oscillatory movements required during walking and running. The MC-PEA will represent an energy-efficient alternative to the ubiquitous series-elastic actuator (SEA) in applications in which the SEA is currently the go-to solution. In addition, this award will support training and mentorship of graduate students, inclusion of undergraduate students in research, and improvements to teaching curriculum.The objective of this grant is to characterize the natural and forced dynamics of the magnetic cogging parallel-elastic actuator (MC-PEA) and determine how to control it effectively and efficiently for robotic motions. The work will improve understanding of the performance specifications of an optimally designed MC-PEA across potential parameter variations. The benefits of the MC-PEA will be explored through application in powered ankle prosthesis and legged robots. The approach includes investigation of bioinspired dynamic motion primitives—including impedance control, point-to-point sub-movements, and oscillations—using a two-link robotic leg with a simple point-like foot and with MC-PEAs powering the hip and the knee. The research also includes development of custom energy regeneration circuits that can be rapidly switched on and off to enable energy to be reclaimed during dynamic movements. The project outcomes will be the optimal parametric designs of the magnetic cogging-torque element (CTE) for a wide variety of step sizes, to be disseminated to robot designers.This project is supported by the cross-directorate Foundational Research in Robotics program, jointly managed and funded by the Directorates for Engineering (ENG) and Computer and Information Science and Engineering (CISE).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.