Pennate actuators: force, contraction and stiffness
Pennate actuators: force, contraction and stiffness
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DOI：
10.1088/1748-3190/ab860f
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发表时间：
2020-07-01
影响因子：
3.4
通讯作者：
Bryant, Matthew
中科院分区：
文献类型：
--
作者：
Jenkins, Tyler;Bryant, Matthew
分层致动器由布置成系统的多个单独的致动器元件组成，导致改进和扩展的性能。天然肌肉组织是分层致动的复杂且多层次的示例，其层次从微米跨越到厘米尺度。除了层次结构之外，肌肉组织还存在不同的几何排列。羽状肌组织由其从肌肉组织作用线倾斜延伸的特征纤维表示，利用几何复杂性来转换纤维输入和肌肉组织输出之间的关系。在本文中，生物启发的分层羽状驱动器的详细说明。这项工作扩大了以往的羽状致动器的研究，通过推导本构力，收缩和刚度模型的一般羽状致动器，其中的组成纤维可以从任何线性致动器。这些模型进行了实验验证，通过研究与McKibben人工肌肉构成的致动器纤维的羽状执行器。使用McKibben人工肌肉是因为它们具有高的力-重量比并且构造成本低廉，使它们成为分层致动器和移动的机器人的有吸引力的候选者。使用导出的本构模型，一般羽状执行器的性能更好地理解通过分析的传动比，阻塞力，和自由收缩。负荷收缩和刚度等张和等压收缩期间也探讨。结果允许知情的设计决策和相关的权衡时，重新创建的显着性能的羽状肌肉组织的理解。未来的工作将利用本文的结果来创建一个自适应羽状致动器，能够改变配置响应力，收缩和刚度的需求。
Hierarchical actuators are comprised of multiple individual actuator elements arranged into a system, resulting in improved and expanded performance. Natural muscle tissue is a complex and multi-level example of hierarchical actuation, with its hierarchy spanning from the micrometer to the centimeter scale. In addition to a hierarchical configuration, muscle tissue exists in varying geometric arrangements. Pennate muscle tissue, denoted by its characteristic fibers extending obliquely away from the muscle tissue line of action, leverages geometric complexity to transform the relationship between fiber inputs and muscle tissue outputs. In this paper, a bioinspired hierarchical pennate actuator is detailed. This work expands on previous pennate actuator studies by deriving constitutive force, contraction, and stiffness models for a general pennate actuator, where the constituent fibers can be constructed from any linear actuator. These models are experimentally validated by studying a pennate actuator with McKibben artificial muscles constituting the actuator fibers. McKibben artificial muscles are used because they have a high force-to-weight ratio and are inexpensive to construct, making them an attractive candidate for hierarchical actuators and mobile robotics. Using the derived constitutive models, general pennate actuator performance is better understood by analyzing the transmission ratio, blocked force, and free contraction. Loaded contractions and stiffness during isotonic and isobaric contractions are also explored. The results allow for informed design decisions and an understanding of the associated tradeoffs when recreating the remarkable properties of pennate musculature. Future work will leverage the results of this paper to create an adaptive pennate actuator that is capable of changing configuration in response to force, contraction and stiffness demands.