Magnetorheological Fluid‐Based Flow Control for Soft Robots

Fluidic soft robots bring a high degree of dexterity and adaptability to robotics problems requiring safe interactions with complex structures. While they are low cost and easy to manufacture, they are difficult to control due to their typical reliance on external pressure sources that become bulky as more degrees of freedom are introduced to the robot. Various techniques from microfluidics and fluid logic are used to introduce valves into soft robots to increase their autonomy, although this has frequently introduced unwanted rigidity. Herein, a magnetorheological (MR) fluid valve that uses magnetic fields to control the pressure within a continuous‐flow fluidic actuator is introduced. A predictive model for the pressure drop in such a flow is presented and validated experimentally. Guidelines for the design of single‐ and multiactuator systems with a single inlet and outlet are presented. The introduction of actuation methods that simplify fluidic control via the application of magnetic fields leads to robots capable of increased autonomy in a scalable and compliant format. Fluid‐powered soft robots are limited in autonomy by their reliance on tubing, tethering them to external pressure controllers. A method to control fluidic soft robots using magnetorheological (MR) fluid is presented, whereby magnetic fields applied to a single recirculating channel of MR fluid control the pressure in an arbitrary number of independent actuators.