CAREER: Mechanically Adaptive, Energetically Passive Robotics

这个教师早期职业发展计划（CAREER）项目将创建机器人外骨骼，为穿戴者提供超出无人辅助的能力，在某种程度上以前认为需要外部驱动器，如电动机或气缸。无动力的机械装置已经被用于提高性能--一个人骑自行车比步行能走得更远更快。然而，在这个项目中考虑的外骨骼超越了这种熟悉的被动装置，通过集成主动控制的能量存储，在可控刚度的弹簧的形式。这项研究的科学贡献是机械自适应能量被动机器人的理论框架，其中存储在可控刚度弹簧中的能量可以与弹簧的变形解耦。这种新的能力可以实现前所未有的人类和机器人移动性。作为示例，在常规弹簧蹦床上跳跃的人可以通过进行一系列连续增加高度的跳跃来积累用于期望的跳高的能量。相比之下，可伸缩弹簧机器人肢体可以通过一系列固定深度的下蹲来积累目标跳跃所需的能量，而不是跳跃，这可能更安全，更可取。该项目将产生重大的社会影响，促进为老年人创造新型辅助设备，为紧急救援人员提供增强性能的外骨骼，并为高效的无动力运输提供自行车的腿替代品。该项目将促进一个新的工程课程，强调在无动力机械系统的控制能量储存和释放。外展活动将包括原型的公开展览和基于知识的新闻报道，关于用于人类增强和运输的新设备。这项研究的重点是一个新的建模和设计框架，用于分析和创建机械自适应，能量被动的机器人。这些机器人的一个关键组成部分是机械自适应顺应性结构的集成，称为可编程弹簧。可编程弹簧是一种新型的机械元件，它联合收割机了杠杆和弹簧的优点，其关键特征是能够实现接近零的能量成本机械适应，而无论弹簧中存储的能量如何。具体的项目目标是：（一）使用可编程弹簧制定一个全面的机器人肢体模型;（二）定义一种基于共振的控制方法，机器人和人类可以使用这种方法来利用可编程弹簧的好处，例如，尽管肢体力量有限，肢体运动有限，但通过多次下蹲和迈步来最佳地积累能量;和（iii）通过巩固性能和用户舒适度之间的权衡来建立腿式运输的物理限制，类似于轮式运输。这些结果将使人类的移动能力在无动力设备中得到前所未有的提高。研究结果还将提高移动的机器人系统的能源效率，以延长任务并提高自主性。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This Faculty Early Career Development Program (CAREER) project will create robot exoskeletons that provide the wearer with capabilities beyond those of an unassisted human, to an extent previously thought to require externally powered actuators, such as electric motors or pneumatic cylinders. Unpowered mechanical devices are already used for performance enhancement -- a person can travel much farther and faster on a bicycle than they can on foot. However, the exoskeletons considered in this project go beyond such familiar passive devices by integrating actively controlled energy storage, in the form of springs of controllable stiffness. The scientific contribution of this research is a theoretical framework for mechanically adaptive energetically passive robotics where the amount of energy stored in a spring of controllable stiffness can be decoupled from the deformation of the spring. This new capability could enable unprecedented human and robot mobility. As an example, a person jumping on a conventional spring trampoline can build up energy for a desired high leap by making a series of jumps of successively increasing height. In contrast, a controllable-spring robot limb could allow the necessary energy for the target leap to be accumulated over a series of fixed-depth squats, instead of jumps, which can be safer and more desirable. The project will have significant societal impacts by facilitating the creation of novel assistive devices for the elderly, performance-augmenting exoskeletons for emergency responders, and legged alternatives to bicycles for efficient unpowered transportation. The project will promote a new engineering curriculum emphasizing controlled energy storage and release in unpowered mechanical systems. Outreach activities will include public exhibits of prototypes and knowledge-based journalism about novel devices used for human augmentation and transportation.The focus of this research is a new modeling and design framework for the analysis and creation of mechanically adaptive, energetically passive robots. A key component of these robots is the integration of mechanically adaptive compliant structures, referred to as programmable springs. Programmable springs are a new class of mechanical elements that combine the benefit of levers and springs, with the key feature that enables near-zero energy cost mechanical adaptation, irrespective of the energy stored in the spring. The specific project goals are to (i) formulate a comprehensive model of robot limbs using programmable springs; (ii) define a resonance-based control method robots and humans could use to leverage the benefits of programmable springs, for example, optimally accumulate energy through multiple squats and steps despite limited limb force and limited limb motion; and (iii) establish the physical limits of legged transportation by consolidating the trade-off between performance and user-comfort similar to wheeled transportation. The results will enable levels of human mobility enhancement unprecedented in unpowered devices. The results will also lead to increased energy efficiency in mobile robotic systems for extended missions and improved autonomy.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.