ElectricallyDriven Soft Fluidic Actuators Combining Stretchable Pumps With Thin McKibben Muscles Soft wearable robots could provide support for lower and upper limbs, increase weight lifting ability, decrease energy required for walking and running, and even provide haptic feedback. However, to date most of wearable robots are based on electromagnetic motors or fluidic actuators, the former being rigid and bulky, the latter requiring external pumps or compressors, greatly limiting integration and portability. Here we describe a new class of electricallydriven soft fluidic muscles combining thin, fiberlike McKibben actuators with fully Stretchable Pumps. These pumps rely on ElectroHydroDynamics, a solidstate pumping mechanism that directly accelerates liquid molecules by means of an electric field. Requiring no moving parts, these pumps are silent and can be bent and stretched while operating. Each electricallydriven fluidic muscle consists of one Stretchable Pump and one thin McKibben actuator, resulting in a slender soft device weighting 2 g. We characterized the response of these devices, obtaining a blocked force of 0.84 N and a maximum stroke of 4 mm. Future work will focus on decreasing the response time and increasing the energy efficiency. Modular and straightforward to integrate in textiles, these electricallydriven fluidic muscles will enable soft smart clothing with multifunctional capabilities for human assistance and augmentation.

Soft PolymerElectrolyteFuelCell Tube Realizing AirHoseFree Thin McKibben Muscles Among the various pneumatic actuators, thin McKibben muscles are particularly attractive owing to their high performance in terms of high contraction ratio, high flexibility, and productivity. One of the challenges for thin McKibben muscles and other pneumatic actuators is the fact that they generally need air hoses and air sources like compressors. This necessarily leads to bulky systems. To solve this problem, we propose and study a new approach to driving pneumatic actuators that exploits electrolysissynthesis of water by a polymer electrolyte fuel cell (PEFC). This method could inprinciple have high applicability to thin McKibben muscles. However, one challenge must still be addressed for the realization of an electrically driven thin McKibben muscle: the development of a tubeshaped soft PEFC. This paper proposes an electrically driven thin McKibben muscle with a tubeshaped soft PEFC realized through a flowing nonelectrolytic plating method. First, the proposed thin McKibben muscle is briefly described. Then, a novel method for plating a tubeshaped soft PEFC using reflux is introduced, and its fundamental operation is tested. After the evaluation of the PEFC, we report a prototype realization of the proposed thin McKibben muscle. The developed prototype has a length of over 170 mm, a diameter of 4 mm, and high flexibility for bending. Finally, we elaborate on a driving experiment through which fundamental characteristics were experimentally evaluated. The prototype thin McKibben muscle succeeded in electrically controlling contraction and expansion motion with a flexible and bendable structure.