Design and Fabrication of a Magneto-rheological Fluid Based Torque Sensor for Automotive Application

Abstract

A magneto-rheological (MR) based torque sensor is a device that transmits the torque by the cutting force of the MR fluid. The magneto-rheological fluids technology has been tested for many industrial applications, such as dampers, actuators, etc. A MR fluid is an intelligent material whose rheological characteristics change rapidly and can be easily controlled in the existence of an applied magnetic field. It presents a viscous coupling controllable by torque, the coupling consists of two types of discs, one is connected to a housing (fixed discs), and the other is connected to an axis (rotating discs). The drive discs and the follower discs are arranged in turn and are interleaved. The MR fluid is filled in the housing. The magnetic fields freeze the fluid so that the shearing torque is generated between the diving discs and the follower discs due to the shears between the slots in the discs below the magnetic fields. The torque is controlled by electromagnets. To have a large pair with small electrical power, the coil turns must be large, so that the response is delayed due to the inductance of the coil. A comparison between the magnetic flux and the intensity of the designs obtained from finite element analysis allow to derive the best design for the prototype in order to proof the concept. The turn of the winding coil and the current as a fixed value is 1500 turn and 1 A current.