Soft material actuation by atomization
Soft material actuation by atomization
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DOI：
10.1088/1361-665x/aaf5a1
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发表时间：
2019-01
影响因子：
4.1
通讯作者：
Han-Joo Lee;K. Loh
中科院分区：
文献类型：
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作者：
Han-Joo Lee;K. Loh
软机器人由于其柔顺性和实现高自由度运动的潜力而受到极大关注，这对于模仿仿生系统至关重要。已经开发了各种方法来致动软材料，范围从气动致动到实施相变。然而，涉及流体压力的技术需要栓系管和外部压缩机，而相变通常依赖于高温变化。在这项研究中，实现了一种新的驱动方法，采用超声雾化诱导相变的液体嵌入在软材料内的空腔。简而言之，雾化是通过在液体层上施加超声波以在表面产生毛细波来实现的，然后小液滴从波峰喷射出来。通过雾化产生的小液滴大大增加了蒸发速率，而无需将温度升高至沸腾。在这项研究中，中空结构制造的软弹性体，部分填充乙醇。超声波通过结构的壁传播以使嵌入的乙醇溶解。与通过加热蒸发本体乙醇相比，雾化嵌入的乙醇表现出高达10倍的更快的致动速率。结果表明，通过调节激励换能器的信号电压和频率，可以控制换能器的驱动性能。此外，成功验证了无需冷却结构的重复来回移动。
Soft robotics are receiving great attention due to its compliant nature and its potential for achieving high degree-of-freedom motions, which are essential for mimicking bioinspired systems. Various methods have been developed to actuate soft materials, ranging from pneumatic actuation to implementing phase transformation. However, techniques that involve fluid pressure require tethered tubes and external compressors, whereas phase transformation generally relies on high temperature changes. In this study, a novel method of actuation that employs ultrasonic-atomization-induced phase transformation of liquid embedded in cavities within soft materials is achieved. In short, atomization is achieved by applying ultrasonic waves on a layer of liquid to create capillary waves at the surface, where small droplets are then ejected from the crests. Small droplets generated by atomization drastically increase the evaporation rate without the need to increase the temperature to boiling. In this study, hollow structures were fabricated with a soft elastomer that were partially filled with ethanol. Ultrasonic waves were propagated through a wall of the structure to atomize the embedded ethanol. Atomizing the embedded ethanol demonstrated as high as ∼10 times faster actuation rates as compared to evaporating bulk ethanol through heating. The results showed that actuation performance could be controlled by adjusting the voltage and frequency of the signal exciting the transducer. Furthermore, repetitive back-and-forth movement without having to cool the structure was successfully validated.