Enfolded Textile Actuator for Soft Wearable Robots

The usage of soft textile materials in wearable robotics shows several advantages compared to rigid robotic parts. We describe a soft pneumatic bending actuator composed of one folded textile tube (flexor) surrounded by another straightening textile tube (extensor). Each actuator is made of two parts: an inflatable tube and housing. Tubes are made of a bladder wrapped by textile. A soft spiral structure was inserted inside the bladder to prevent air jamming. We describe the design and fabrication of the actuator, provide an analytical model of the torque, and characterize the actuator performance. The actuator is made with different sizes to be used in a large range of applications such as robotic hands, robotic arms, and wearable soft exosuits. Five actuators were attached to a commercial glove fingers and form a wearable glove, the glove shows different gestures and it is able to hold 9 kg weights. With a larger scale, the bending actuator was able to hold 20 kg. In addition, a preliminary experiment shows a reduction of 50% in EMG signals reflecting muscle activities during 9 kg weight bar grasping and releasing stages.