Passive Flow Control for Series Inflatable Actuators: Application on a Wearable Soft-Robot for Posture Assistance
This work addresses posture assistance for infants with cerebral palsy using a wearable soft-robot, representing an incremental improvement in passive control methods for soft robotics.
The paper tackled the problem of controlling multiple degrees of freedom in soft pneumatic robots by developing a passive flow control method using 3D printed flow resistor tubes, which enabled sequential activation of series inflatable actuators from a single pressure source, validated through tests on a wearable robot-suit for infant posture assistance.
This paper 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.