Multi-state, three-way, normally open mini valve based on 3D printed flexible magnets using origami-inspired magnetization

Electromagnetic mini valves for controlling pneumatic soft actuators are attracting widespread interest in recent years. However, it is known that the traditional electromagnetic valves on the millimeter scale generally have three or fewer working states, and their moving parts are usually permanent magnets with a special shape that needs expensive manufacturing. To overcome these problems, this study aims to develop a mini valve with four working states based on flexible magnets at a low fabrication cost. We take full advantage of low-cost 3D-printed magnets’ physical and magnetic properties and improve their performance through origami-inspired magnetization. A fixed-beam-structure flexible magnet is proposed to control this valve via deformation so that valve’s two sides can be driven independently, resulting in four working states. Compared with conventional sintered magnets, 3D printing magnets can be manufactured quickly and affordably. Due to the proposed valves’ more operating states than the state-of-art three-way ones, they are proven to reduce the number of small control elements in the pneumatic system. The maximum flow rate of the valve at 5 kPa air pressure was 0.81 l min⁻¹ at the power consumption of 20 W. This mini valve has the potential in controlling multi-degree-of-freedom pneumatic soft actuators.