Soft robotic actuation with pressure-driven magnetorheological (MR) fluid flow



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Soft robots can complete tasks that rigid robots cannot. These compliant, dexterous machines are well suited to delicate tasks in difficult environments such as within the human body and the deep sea. Fluidically actuated robots are popular due to their simple design, high force output, and safety. However, complex robots often consist of many actuators working together. These actuators can be difficult to control independently, and require many bulky tubes limiting the robots’ autonomy. Many techniques have been employed to integrate pressure control directly onboard the robots themselves, including using smart fluids like magnetorheological fluid (MRF). This project explores the use of MRF to actuate soft robots. The device flows MRF through the actuator using a peristaltic pump, and an applied magnetic field initiates actuation by locally solidifying the fluid. This creates a pressure buildup in the actuator, which bends due to a differential stiffness. We investigate how different properties of the MRF (particle size, non-Newtonian rheology, etc.) affect actuation efficacy. The actuation efficacy is quantified by the speed of actuation and the force produced by the actuator. The results are compared to determine the best combination of MRF parameters and device architecture for robust actuation.



Soft robotics, Magnetorheological fluid, Actuators, Fluidic actuation