Manufacturing the Next-Generation of Soft Robotics with Ultra-Efficient, Strong, Electro-Mechanical Artificial Muscles

随着人类开始更多地与机器人互动，我们将需要各种形状的适应性机器：制造机器人与人并肩工作，可穿戴设备从受伤中康复，智能假肢增强人类能力等等。在这些截然不同的领域，最紧迫的挑战必须找到为这些设备提供动力的人造肌肉或软执行器。该领域过去的方法由于操作复杂(例如，需要由泵驱动并由阀门引导的流体执行器)、响应速度慢(例如，离子聚合物-金属复合材料的扩散受限，使得它们明显比自然肌肉慢得多)和低能量效率(例如，在形状记忆合金中，大部分输入电能以热的形式损失到环境中，并且不被用来触发相变)而受到限制。拟议的研究计划将开发基于介电弹性体致动器(DEAS)的下一代人造肌肉，DEAS是一种柔顺电容器，当在两个可伸缩电极之间施加电场时，这些电容器会发生机械变形。与其他技术相比，DEAS是柔软的(对于没有框架的多层DEA)，仅由电输入驱动，并且像大多数自然肌肉一样强壮和快速。拟议的研究项目借用了我之前拥有专业知识的领域的概念，包括电化学、材料科学和折叠折纸结构。DEA通常是从机械的角度来描述的，在不同的驱动频率下评估力输出和位移，而不评估相应的电气性能。我的研究小组将研究DEAS在驱动过程中的电气行为，类似于电池如何通过重复充电/放电循环来表征。使用这种方法，我们将对DEAS长期行为中电气和机械应力之间的相互作用有一个前所未有的观察。同样，DEA失效通常归因于弹性体的行为，没有仔细检查电极或弹性体-电极界面。通过超薄电极和新的表征技术，我们将把材料微结构与器件性能联系起来。最后，DEA通常在相对刚性的框架内操作，这限制了运动范围，并使机器人集成具有挑战性。通过扩展新的2D制造技术，我的团队将为下一代软机器人构建具有嵌入式致动器的复合结构。该研究计划植根于机械工程，使用新的工具和工艺为如何制造、评估人造肌肉并将其集成到智能设备和机器人中设定新的标准。该项目完成后，将在人类和机器人互动的一系列领域找到应用，包括协作制造、假肢、触觉通信设备等。

As humans start to interact more with robots, we will require adaptable machines in a variety of shapes: manufacturing robots to work side-by-side with people, wearable devices to rehabilitate from injury, smart prosthetics to augment human capability, etc. Across these vastly different areas, the most pressing challenge has to find the artificial muscles, or soft actuators, to power these devices. Past approaches in the field have limitations due to complex operation (e.g., fluidic actuators need to be driven by pumps, and directed by valves), slow response speed (e.g., ionic polymer-metal composites are diffusion limited, making them significant slower than natural muscles), and low energy efficiency (e.g., in a shape memory alloy most of the input electrical energy is lost as heat to the environment, and not used to trigger the phase change). The proposed research program will develop the next generation of artificial muscles, based on dielectric elastomer actuators (DEAs), compliant capacitors that undergo mechanical deformation when an electric field is applied between two stretchable electrodes. Compared to other technologies, DEAs are soft (for multilayer DEAs without a frame), driven by only an electrical input, and as strong and fast as most natural muscles. The proposed research programs borrows concepts from areas in which I have previous expertise, including electrochemistry, materials science, and folding origami structures. DEAs are most often characterized from a mechanical standpoint, evaluating the force output and displacement, at different actuation frequencies, without evaluating the corresponding electrical properties. My research group will study the electrical behavior of DEAs during actuation, similar to how batteries are characterized by repeated charge / discharge cycles. Using this approach we will have an unprecedented look at the interplay between electrical and mechanical stress in the long term behavior of DEAs. Similarly, DEA failure is generally attributed to the behavior of the elastomer, without close examination of the electrode or the elastomer-electrode interface. With ultra-thin electrodes and novel characterization techniques, we will link material microstructure to device performance. Lastly, DEAs are often operated within a relatively rigid frame, which limits the range of motion and makes robot integration challenging. By expanding upon novel 2D fabrication techniques, my group will build composite structures with embedded actuators for the next generation of soft robotics. The research program is rooted in Mechanical Engineering, using novel tools and processes to set new standards for how artificial muscles are manufactured, evaluated, and integrated into smart devices and robotics. When completed, the program will find applications in a range of fields where humans and robots interact, including collaborative manufacturing, artificial limbs, tactile communication devices, and beyond.