EAGER: Characterizing vertical swimming, payload capacity, and performance envelope of biohybrid robot jellyfish as future ocean monitoring platforms

随着气候的变化，对海洋及其密切相关的生态系统的健康进行监测、绘图和建模的需求比以往任何时候都更加重要。生物记录，即，利用动物身上的传感器收集关于动物行为、生理及其周围环境的数据，已成为许多气候变化和海洋评估模型的重要投入，提供了否则无法获得的海洋区域的环境数据。然而，生物记录的一个主要限制是，它只提供动物主动游泳或被动携带的位置的数据。生物混合机器人控制，或沿着期望的轨迹引导活体动物沿着的能力，将解决生物记录和传统机器人感测系统中的当前限制。加州理工学院最近开发的技术已经证明了在实验室和海洋中机器人控制月亮水母（奥雷利亚aurita）单向游泳的能力。一个带有两个电极的小型微控制器插入水母的中心，引起电刺激，使这些生物混合机器人水母能够根据命令以3倍于自然能力的速度游泳。这些生物混合机器人水母有潜力扩大垂直海洋剖面任务，特别是在现有技术特别有限的情况下。由于巨大的压力和深度以及相关的技术费用的限制，深海的采样严重不足。然而，深海测量对于了解海洋与气候之间的相互作用极为重要。水母天生适合深海的恶劣条件，生物混合机器人水母由于上升流和下降流的原因，游泳的速度比背景垂直水流大一个数量级。生物混合机器人水母平台将解决目前海洋剖面技术的许多局限性，因为它们：1）成本低，2）全球动物可用性和开源技术，3）节能，长时间推进，4）有限的环境干扰（小尺寸和最小的尾流），以及5）大群部署的潜力。这项工作对社会产生的更广泛影响包括建立一个经济上更容易获得的垂直剖面海洋传感平台。一旦该平台的性能包络在该项目中得到表征，就可以将带有额外传感器、天线和GPS的新生物记录标签纳入其中。由于这项技术将是开源的，其他研究人员将能够修改和进一步优化这个平台。在当地范围内，这项研究将通过对代表性不足的学生的直接指导，以及研究人员参与研讨会，重点是增加这个研究社区的多样性。生物混合机器人水母的第一代原型已经显示出重要的，但尚未实现的潜力，作为未来的海洋传感平台，可以补充和加强现有的海洋传感技术。然而，需要进一步的研究和开发，以优化协议，为生物混合水母配备环境传感标签，在现实的实地条件下进行长期的垂直海洋剖面分析。该项目将说明生物混合机器人水母改良版在海洋垂直剖面分析具体应用方面的能力。研究活动将包括：1）简化游动控制器接口，用于更即插即用、全局可扩展的控制器，2）量化生物混合机器人水母的最大有效载荷相对于身体尺寸的缩放，3）将现成的生物记录标签（iTAG）与游动控制器接口集成，4）评估生物混合水母的可实现的测量持续时间和空间范围，用于长期部署，以及5）展示了成功的机载控制和数据检索装备的生物混合机器人水母垂直海洋剖面在南部加州的沿海和开放的海洋环境。这个奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

In light of a changing climate, the need to monitor, map, and model the health of the ocean and its closely associated ecosystems is more vital than ever. Biologging, i.e., the use of animal-attached sensors to collect data on animal behavior, physiology, and their surrounding environment, has become an important input for many climate change and ocean assessment models, providing environmental data on regions of the ocean that would be otherwise inaccessible. However, a major limitation of biologging is that it only provides data at locations where the animal actively swims or is passively carried. Biohybrid robotic control, or the ability to steer a living animal along a desired trajectory, would address current limitations in both biologging and traditional robotic sensing systems. Recent technology developed at Caltech has demonstrated the ability to robotically control the unidirectional swimming of a moon jellyfish (Aurelia aurita) in the laboratory and ocean. A small microcontroller with two electrodes inserted into the center of the jellyfish induces electrical stimulation that allows for these biohybrid robotic jellyfish to swim on command and at speeds 3 times their natural abilities. These biohybrid robot jellyfish have to the potential to expand vertical ocean profiling missions in particular, where existing technology is especially constrained. The deep ocean is vastly under-sampled due to limitations associated with immense pressure and depth and their associated technological expense. However, deep sea measurements are extremely important for understanding the interplay between the ocean and climate. Jellyfish are naturally suited to the harsh conditions of the deep, and biohybrid robot jellyfish swim at speeds an order of magnitude larger than background vertical currents due to upwelling and downwelling. Biohybrid robotic jellyfish platforms would address many of the limitations of current ocean profiling technologies, due to their: 1) low cost, 2) global animal availability and open-source technology, 3) energy-efficient, long-duration propulsion, 4) limited environmental disturbance (small size and minimal wake), and 5) potential for deployment in large swarms. The societal broader impacts for this work include the creation of a more economically accessible, vertical profiling ocean sensing platform. Once the performance envelope of this platform is characterized in this project, new biologging tags with additional sensors, antennas, and GPS can be incorporated. Because this technology will be open source, other researchers will be able to modify and further optimize this platform. On a local scale, this research will engage with the community through the direct mentorship of underrepresented students, as well as researcher participation in workshops focused on increasing the diversity of this research community.The first-generation prototype of the biohybrid robotic jellyfish has demonstrated significant but unrealized potential to act as a future ocean sensing platform that can supplement and enhance existing ocean sensing technologies. However, further research and development is needed to optimize the protocol for equipping biohybrid jellies with environmental sensing tags for long-term, vertical ocean profiling under realistic field conditions. This project will characterize the capabilities of a modified version of biohybrid robotic jellyfish for the specific application of vertical ocean profiling. Research activities will include: 1) simplifying the swim controller interface for a more plug-and-play, globally scalable controller, 2) quantifying the scaling of maximum payload versus body size for biohybrid robot jellyfish, 3) integrating an off-the-shelf biologging tag (iTAG) with the swim controller interface, 4) assessing the achievable measurement duration and spatial range of biohybrid jellyfish for long-term deployments, and 5) demonstrating successful onboard control and data retrieval of equipped biohybrid robot jellyfish for vertical ocean profiling in coastal and open ocean environments in southern California.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.