Switching control of latex balloon expansion by using switching valve mediated with the Coanda effect

Soft robots have advantages in terms of safety, softness, and compliance compared to traditional robotic systems. However, fluid-driven soft actuators, often employed in soft robots, require a corresponding number of bulky pressure supplies/valves to drive. Here, we consider a valve that can control the flow without mechanical moving parts for simplifying the driving system of soft actuators. We developed a system comprising a pump, a switching valve, and two latex balloons to demonstrate the feasibility of introducing a fluid valve into soft robotics. As the valve, which makes use of the Coanda effect, can switch the flow between two outlets when the pressure difference between the outlets is 3 kPa, we employed a latex balloon connected to each outlet. The system can control the expansion of each balloon by switching the flow from the pump. The experimental results proved that the system could actuate each balloon.