An electrochemical dual transducer (ECDT) based on a chemical reaction is a new fluidic machine for self-sensing actuation. Recently, incorporating sensors has enhanced the multifunctionality of soft robots with fluidic machines such as pumps or compressors. However, conventional fluidic systems have limitations such as heavy weight, noise, bloat, and complexity. In our previous research, we adopted small-sized, lightweight, and quiet electrohydrodynamic pumps for soft robots. In this paper, we propose a new ECDT by exploring the possibility of an electrohydrodynamic (EHD) pump to sense the flow of the working fluid. The current in the ECDT is proportional to 1/3 of the inflowing velocity. We also clarify its mechanism, mathematical model, range of detectable flow rate, sensitivity factor, relaxation time, response speed, and pumping characteristics. The advantages of the ECDT are their small size, light weight, simple fabrication process, extensibility of the sensing range, and sensitivity. We also demonstrate a suction cup driven by the ECDT, which can detect, hold, and release objects. We expect a bidirectional ECDT will realize a small, multifunctional, and straightforward fluidic system.

Electrostatic actuators, which are characterized by low weight, power consumption, noise, and remaining heat, have been studied widely and are expected to find use in wearable devices. However, they require high‐voltage control and safety circuits, which may increase their bulk. Herein, a soft electrostatic generator is proposed for use in wearable devices. Specifically, streaming electrification is used, wherein electric charge is generated through the interactions between a fluid and a solid material (the developed system is named a “streaming electrification generator”). The contact area with the insulating fluid is increased by using a porous material, and the amount of charge generated is increased to the level needed to drive electrostatic actuators using materials with different dielectric characteristics. Moreover, the generator is made of soft materials and therefore can adapt to the shape of the human body and not interfere with its movement. Finally, it is ideal for wearables because it does not use materials that are harmful to the human body. Thus, the developed system, which is made of soft materials, is a novel power generator and should be suitable for electrostatic actuators used in wearable devices.

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