Preston Daniel J, Jiang Haihui Joy, Sanchez Vanessa, Rothemund Philipp, Rawson Jeff, Nemitz Markus P, Lee Won-Kyu, Suo Zhigang, Walsh Conor J, Whitesides George M
Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford St., Cambridge, MA 02138, USA.
Wyss Institute for Biologically Inspired Engineering, 3 Blackfan Circle, Boston, MA 02115, USA.
Sci Robot. 2019 Jun 26;4(31). doi: 10.1126/scirobotics.aaw5496.
Periodic actuation of multiple soft, pneumatic actuators requires coordinated function of multiple, separate components. This work demonstrates a soft, pneumatic ring oscillator that induces temporally coordinated periodic motion in soft actuators using a single, constant-pressure source, without hard valves or electronic controls. The fundamental unit of this ring oscillator is a soft, pneumatic inverter (an inverting Schmitt trigger) that switches between its two states ("on" and "off") using two instabilities in elastomeric structures: buckling of internal tubing and snap-through of a hemispherical membrane. An odd number of these inverters connected in a loop produces the same number of periodically oscillating outputs, resulting from a third, system-level instability; the frequency of oscillation depends on three system parameters that can be adjusted. These oscillatory output pressures enable several applications, including undulating and rolling motions in soft robots, size-based particle separation, pneumatic mechanotherapy, and metering of fluids. The soft ring oscillator eliminates the need for hard valves and electronic controls in these applications.
多个柔软的气动致动器的周期性驱动需要多个独立组件的协同作用。这项工作展示了一种柔软的气动环形振荡器，它使用单一的恒压源在柔软致动器中诱导出时间上协调的周期性运动，无需硬阀或电子控制。这个环形振荡器的基本单元是一个柔软的气动逆变器（一个反相施密特触发器），它利用弹性体结构中的两种不稳定性在其两种状态（“开”和“关”）之间切换：内部管道的屈曲和半球形膜的快速通过。奇数个这样的逆变器连接成一个回路会产生相同数量的周期性振荡输出，这是由第三种系统级不稳定性导致的；振荡频率取决于三个可以调节的系统参数。这些振荡输出压力可实现多种应用，包括软机器人中的起伏和滚动运动、基于尺寸的颗粒分离、气动机械疗法以及流体计量。软环形振荡器消除了这些应用中对硬阀和电子控制的需求。
