A Multi-Stable Electromagnetic Mini Valve for Pneumatic Powertrain Systems: Application in Soft Inchworm-Like Walker

This research explores multi-state mini valves for their integrative potential in pneumatic actuator systems. Although it has been widely recognized that mini valves are used in numerous applications, the majority of current mini valves offer three or fewer working states. Furthermore, those rare valves capable of operating in four working states exhibit limitations, including the necessity for multiple driving sources and elevated operational energy requirements. Our study introduces an electromagnetic valve (R7.5 ×30 mm) that switches between four states using one power source. This valve attains four stable operational states by coordinating interactions between the upper and lower iron cores, a ring magnet, and a cylindrical magnet. The valve exhibits a leak rate of less than 0.01 L/min under pressures up to 250 kPa. Besides, rapid state transitions can be achieved by briefly energizing the valve's coils, resulting in a peak response time of only 0.0075 s and an energy expenditure of just 0.540 J. Leveraging this multi-state valve mechanism, the study unveils the precise control over the locomotion and directional maneuvers of a pneumatic soft inchworm-like walker, culminating in a propulsion velocity of 0.072 BL/s. This achievement underscores the latent potential of multi-state valves in the miniaturization of pneumatic systems.