Optimal design of a new multipole bilayer magnetorheological brake

Abstract

This article presents a new high-torque multipole bilayer magneto-rheological brake (MRB). This MRB has a unique structural design with multiple electromagnetic poles and multiple media layers of magnetorheological fluid (MRF). The MRB has two rotors located on the outer and inner sides of a six-pole stator, and therefore, it can provide higher torque and a larger torque-to-volume ratio (TVR) than conventional single- or multipole single-layer MRBs can. Moreover, the problem of potential MRF leakage is solved by using cylindrical separator rings around the stator. In this study, first, the structure of the proposed MRB is introduced. An analog magnetic circuit was built for the MRB to investigate the effects of the MRB parameters on the magnetic field intensity of the MRF layers. In addition, a 3D electromagnetic model of the MRB was developed to simulate and examine the magnetic flux intensity and corresponding braking torque. An approximate optimization method was then applied to obtain the optimal geometric dimensions for the major dimensional parameters of the MRB. The MRB was manufactured and tested to validate its torque and dynamic characteristics. The results showed that the proposed MRB exhibited great enhancement of the braking torque and TVR.

Magneto-rheological actuator with permanent magnets for low-power activation

“…The MRBs have been studied with the purpose of optimizing maximum torque output for the smallest overall volume. This usually results in complex or large internal geometries to route flux through the MRF or increasing coils and electrical current to generate large magnetic fields (LORD Corporation, 2017; May, 2013; Rossa et al, 2014b; Shiao et al, 2016; Shiao and Quang-Anh, 2013; Wang et al, 2013). While useful in many applications, these designs rarely consider the power requirements to run the MRB and thermal effects due to coil heating.…”

“…Typical brakes require large, tethered power supplies, often offsetting their good torque-to-volume ratio. A low-power device can be ideal in mobile applications where batteries are used to energize a system, and longer run times are desired (LORD Corporation, 2017; May, 2013; Rossa et al, 2014a; Shiao et al, 2016; Shiao and Quang-Anh, 2013; Wang et al, 2013).…”

“…In a multi-pole, double-rotor MRB (Shiao et al, 2016); six separate coils were mounted on a stator to produce a multi-pole radial magnetic field. To efficiently utilize the geometry for maximum torque, a rotor was placed on the inner and outer surfaces of the stator.…”

Design of a New Bilayer Multipole Electromagnetic Brake System for a Haptic Interface

“…In order to maximize the controllable braking torques in a given volume, some special designs have been proposed by researches. Those include cylindrical-shaped radial-arrangements of multiple electromagnetic poles in the form of layers [11,12]. The superposition principle of magnetic flux across the poles and layers magnifies the range of braking torque.…”

Design and evaluation of a small-scale multi-drum magnetorheological brake

“…Generally, MR fluids are operated in four main modes: valve mode, direct shear mode, squeeze mode and pinch mode (Goncalves and Carlson, 2009; Rossa et al, 2014a). MR actuators can be built in dampers (Parlak et al, 2012; Weber, 2014), valves (Ai et al, 2006; Nguyen et al, 2009), clutches (Shafer and Kermani, 2011; Yadmellat and Kermani, 2014) and brakes (Rossa et al, 2014b; Shiao et al, 2016). They have showed great potential in the fields of vibration control (Choi et al, 2000), rehabilitation (Gudmundsson et al, 2010), robotics (Saito and Ikeda, 2007) and haptics (Blake and Gurocak, 2009; Senkal and Gurocak, 2011).…”