Shape Memory Alloy Actuated Ankle Foot Orthosis for Reduction of Locomotion Force
Shape Memory Alloy Actuated Ankle Foot Orthosis for Reduction of Locomotion Force
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DOI：
10.23919/wac50355.2021.9559533
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发表时间：
2021-08
期刊：
影响因子：
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通讯作者：
Ahmad Alminnawi;Yo Kobayashi;T. Otani;Masao Tanaka
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文献类型：
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作者：
Ahmad Alminnawi;Yo Kobayashi;T. Otani;Masao Tanaka
人类在行走时被认为是低效的，因为他们无法实现理论上理想的“零能量成本”的稳态运动，而这对于具有弹性组织的两足动物来说是可能的。这种低效率主要是由于身体完成一个步骤所产生的部分能量被消耗掉，而不是被储存起来供下一步使用。这表明我们可以通过使用外骨骼设备操纵下肢的弹性来提高运动效率并降低行走的代谢能量成本[1]。然而，大多数传统设计使用由具有恒定刚度的常规材料制成的弹簧。这些器械施加的线性力模式不具有生物相容性，因为它们不模拟人体肌肉或肌腱的力。本文介绍了一个跨学科的研究设计的被动动态踝足矫形器机制，减少运动过程中的生物肌肉力量的要求，从而减少代谢能量的步行成本，同时保持生物相容性。形状记忆合金由于其超弹性而被用作驱动器的智能材料。这种超弹性提供了一种非线性的刚度模式，产生的力与健康肌肉的力相当。
Humans can be considered inefficient at walking because they are unable to achieve the theoretically ideal “zero energy cost” of steady-state locomotion that is possible for bipeds who have elastic tissues. This inefficiency is mainly due to part of the energy that is generated by the body to complete a single step being dissipated instead of being stored for use in the proceeding step. This suggests that we can improve locomotion efficiency and reduce the metabolic energy cost of walking by manipulating the elasticity of the lower limbs using exoskeletal devices [1]. However, most traditional designs use springs made from regular material that have a constant stiffness. These devices exert a linear force pattern that is not biocompatible because they do not mimic the forces of the muscles or the tendons of the human body. This paper presents an interdisciplinary study of the design of a passive–dynamic ankle foot orthosis mechanism that reduces the biological muscle force requirements during locomotion, thus reducing the metabolic energy cost of walking while maintaining biocompatibility. Shape memory alloy is used as a smart material for an actuator owing to its super-elasticity. This super-elasticity provides a nonlinear stiffness pattern that generates forces comparable to those of healthy muscles.