This letter presents a passive control method for multiple degrees of freedom in a soft pneumatic robot through the combination of flow resistor tubes with series inflatable actuators. We designed and developed these 3D printed resistors based on the pressure drop principle of multiple capillary orifices, which allows a passive control of its sequential activation from a single source of pressure. Our design fits in standard tube connectors, making it easy to adopt it on any other type of actuator with pneumatic inlets. We present its characterization of pressure drop and evaluation of the activation sequence for series and parallel circuits of actuators. Moreover, we present an application for the assistance of postural transition from lying to sitting. We embedded it in a wearable garment robot-suit designed for infants with cerebral palsy. Then, we performed the test with a dummy baby for emulating the upper-body motion control. The results show a sequential motion control of the sitting and lying transitions validating the proposed system for flow control and its application on the robot-suit.

中文翻译：

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串联式充气执行器的被动流量控制：在可穿戴软机器人上的姿势辅助应用

这封信提出了一种通过将阻流器管与串联可充气执行器相结合，在软气动机器人中实现多个自由度的被动控制方法。我们基于多个毛细管孔的压降原理设计和开发了这些3D打印电阻器，该电阻器允许从单个压力源被动控制其顺序激活。我们的设计适合标准的管连接器，因此很容易将其用于具有气动入口的任何其他类型的执行器。我们介绍了其压降的特性以及执行器的串联和并联电路的激活顺序的评估。此外，我们提出了一种辅助姿势从躺着过渡到坐姿的应用程序。我们将其嵌入为脑瘫婴儿设计的可穿戴服装机器人套装中。然后，我们对一个模拟婴儿进行了测试，以模拟上身运动控制。结果表明，对坐着和躺着过渡进行了顺序运动控制，从而验证了所提出的流量控制系统及其在机器人套件上的应用。