Magnetorheological Fluid-Based Bending Actuator for Magnetic Sensing

Magnetorheological (MR) fluids have applications in diverse areas such as automobile suspension, architecture, and vibration control due to their fast response, wide range of controllability, and temperature resistance. However, traditional MR fluids-based applications for robotics lack the capability of sensing that can provide information about the environment. In this letter, we present a MR fluid-based bending actuator for magnetic sensing by integrating a strain gage into the actuator. Its deflection can be detected by reading the change of resistance when the actuator deflects under different external magnetic fields. Subsequently, we obtain the relationship between the magnetic flux density and the deflection by deriving an analytical model. To demonstrate the magnetic actuation capability of the actuator, we fabricate a fish-like robot whose tail is composed of the actuator. We further conduct simulations and experiments to validate the analytical model of magnetic sensing. This model shows good agreement with the simulation and experiment results. We validate the actuator for magnetic sensing by demonstrating that it can exhibit a good tracking response of dynamic signals (maximum absolute error smaller than 2.5 mT). The results illustrate that the MR fluid-based bending actuator has the potential to use in the environmental inspection.