Self-organisation of artificial muscles based on the cilia and flagella

该项目属于EPSRC工程和数学科学。人造肌肉是一种具有响应外部刺激而收缩、扩张或旋转能力的材料。人造肌肉具有大的功率重量比和大的运动范围，在推动各种机器人应用方面有着巨大的希望，从机器人假肢和外骨骼到医疗机器人[1]。这类执行器有压电式执行器、形状记忆合金执行器和电活性聚合物执行器等，它们各有优缺点。现有人造肌肉的一个共同问题是难以结合传感器来响应其环境。这些人造肌肉与真正的肌肉纤维的行为是脱节的，在真正的肌肉纤维中，收缩是由分子马达[2]驱动的蛋白质丝相对滑动引起的。同样的机制也适用于纤毛和鞭毛的运动。纤毛和鞭毛是细胞中的毛发状结构，通过将化学能转化为机械功，作为基本的运动单位。博士项目的目的是在纤毛和鞭毛的基础上开发新的人造肌肉细胞。纤毛和鞭毛负责一系列广泛的功能，从游动的藻类到哺乳动物大脑中的液体泵送，是发展新的人造肌肉细胞的一个明智的起点。最近对精子中鞭毛跳动的研究强调了存在于精子鞭毛中的其他结构的重要性。通过将鞭毛建模为弹性细丝，我将使用粗粒度方法来开发精子的三维模型，从而实现有效的模拟。这将使我能够模拟鞭毛的不同结构，并强调它们在高粘度环境中对精子运动的重要性。我还将研究驱动鞭毛跳动的分子马达的自组织，一旦我有了一个合适的模型，我将使用软机器人技术来扩大系统的规模，以创建基于鞭毛的机器人。这里的目的是找到产生能够执行任务的人造肌肉的最小交互集。该博士学位不仅有助于我们对鞭毛运动和精子功能的理解，而且为广泛的机器人应用提供见解。自组织也是在许多自然系统中观察到的普遍特性，包括游动的细菌和鸟群；这确保了博士学位具有影响广泛领域的潜力1]Zhang， Jet al.，机器人人工肌肉：当前进展和未来展望，IEEE机器人学报，第35卷，第761-781页（2019）[2]Sweeney， H., & Holzbaur， E.，马达蛋白，冷泉港生物学展望，vol. 10(2018)[3] Lodish H, Berk a, Zipursky SL，等。分子细胞生物学。第4版。纽约：w·h·弗里曼。第19.4节，纤毛和鞭毛：结构和运动。(2000)

This project falls within the EPSRC Engineering and Mathematical sciences.Artificial muscles are materials characterised by their ability to contract, expand or rotate in response to external stimuli. Capable of large power-to-weight ratios and large ranges of motion, artificial muscles hold great promise for pushing forward various robotic applications, from robotic prosthetics and exoskeletons to medical robots [1]. There exist several actuators in this category, including piezoelectric actuators, shape-memory alloys and electroactive polymer actuators, each with their own advantages and limitations. A common problem with existing artificial muscles is the difficulty incorporating sensors that allow for actuation in response to their environment. These artificial muscles are disconnected from the behaviour of real muscular fibres, in which contraction is caused by the sliding of protein filaments relative to one another, driven by molecular motors [2]. The same mechanism is responsible for the movement of cilia and flagella, which are hair-like structures in cells that act as a fundamental unit of motion by converting chemical energy into mechanical work [3].The aim of the PhD project is to develop new artificial muscle cells based on the cilia and flagella. Responsible for a wide array of functions, from swimming algae to pumping fluid in the brains of mammals [4], cilia and flagella are a sensible starting point for the development of new artificial muscle cells. Recent research into the flagella beating in sperm [5] highlights the importance of additional structures present in sperm's flagella. By modelling the flagella as an elastic filament, I will use a coarse-grained approach [6] to develop a 3-dimensional model of sperm which allows for efficient simulation. This will allow me to model different structures in the flagella and highlight their importance for sperm movement in high-viscosity environments. I will also investigate the self-organisation of molecular motors which drive the flagllum beat, and once I have a suitable model I will use soft robotics to scale up the system to create robotics based on the flagella. The purpose here is to find the minimal set of interactions that give rise to artificial muscles capable of carrying out tasks. This PhD will not only contribute to our understanding of flagella motion and sperm function, but provide insight into a wide array of robotics applications. Self-organisation is also a universal property observered in numerous natural systems, including swimming bacteria and flocks of birds; this ensures that the PhD has potential to impact a wide array of fields1] Zhang, Jet al., Robotic Artificial Muscles: Current Progress and Future Perspectives, IEEE Transactions on Robotics, vol. 35, pp. 761-781 (2019)[2] Sweeney, H., & Holzbaur, E., Motor Proteins,Cold Spring Harbor Perspectives In Biology, vol. 10(2018)[3] Lodish H, Berk A, Zipursky SL, et al. Molecular Cell Biology. 4th edition. New York: W. H. Freeman. Section 19.4, Cilia and Flagella: Structure and Movement. (2000)