Lauflabor Locomotion Lab, Institute of Sports Sciences, University of Jena, Dronburger Strasse 23, Jena, Germany.
Bioinspir Biomim. 2010 Mar;5(1):16004. doi: 10.1088/1748-3182/5/1/016004. Epub 2010 Feb 25.
A reductionist approach was presented to investigate which level of detail of the physiological muscle is required for stable locomotion. Periodic movements of a simplified one-dimensional hopping model with a Hill-type muscle (one contractile element, neither serial nor parallel elastic elements) were analyzed. Force-length and force-velocity relations of the muscle were varied in three levels of approximation (constant, linear and Hill-shaped nonlinear) resulting in nine different hopping models of different complexity. Stability of these models was evaluated by return map analysis and the performance by the maximum hopping height. The simplest model (constant force-length and constant force-velocity relations) outperformed all others in the maximum hopping height but was unstable. Stable hopping was achieved with linear and Hill-shaped nonlinear characteristic of the force-velocity relation. The characteristics of the force-length relation marginally influenced hopping stability. The results of this approach indicate that the intrinsic properties of the contractile element are responsible for stabilization of periodic movements. This connotes that (a) complex movements like legged locomotion could benefit from stabilizing effects of muscle properties, and (b) technical systems could benefit from the emerging stability when implementing biological characteristics into artificial muscles.
为了研究在稳定运动中需要生理肌肉的哪个细节水平，提出了一种简化方法。分析了具有 Hill 型肌肉（一个收缩元件，没有串联或并联弹性元件）的简化一维跳跃模型的周期性运动。肌肉的力-长和力-速关系在三种近似水平（常数、线性和 Hill 非线性）下变化，导致九个不同复杂性的不同跳跃模型。通过返回映射分析评估这些模型的稳定性，并通过最大跳跃高度评估性能。最简单的模型（恒定力-长和恒定力-速关系）在最大跳跃高度上优于所有其他模型，但不稳定。稳定的跳跃可以通过力-速关系的线性和 Hill 非线性特征来实现。力-长关系的特征对跳跃稳定性的影响很小。该方法的结果表明，收缩元件的固有特性负责周期性运动的稳定化。这意味着（a）像腿部运动这样的复杂运动可以受益于肌肉特性的稳定化效果，以及（b）技术系统在将生物特征引入人工肌肉时可以受益于新兴的稳定性。
