Modeling and experimental evaluation of a rotary peristaltic magnetorheological fluid device with low off-state torque for haptic interfaces

This article presents a novel rotary magnetorheological fluid device with inherently low off-state torque. The working principle of the device is similar to peristaltic pumps except the fluid remains inside the device and circulates continuously. Unlike other continuous rotation magnetorheological fluid devices, which operate in shear mode, the proposed device works in pressure driven flow mode. A proof of concept prototype with arbitrary dimensions is built and experimentally evaluated. Measured off-state torque is as low as 20 N. mm. Analytical model of the resistant torque and finite element simulations of the magnetic circuit are presented and validated with the experimental results. Using these models, an optimal device with similar off-state characteristics can be designed to fulfill specific requirements of size, weight, power and on-state torque. The proposed concept is promising especially for use in high precision haptic interfaces that require stability and transparency at the lower end of force spectrum.