Development of Tiny Vane-Type Magnetorheological Brake Considering Quality Function Deployment

Abstract

Many studies focus on the torque-to-dimension ratio when designing magnetorheological brakes (MRB), especially for ankle foot orthosis (AFO) devices. Vane MRB is one type of MRB with a limited angle of motion that is naturally suitable to be applied to AFO. However, very few implement quality function deployment (QFD) when making MRB, whereas QFD is an essential factor in making product designs. In this study, a tiny vane-type MR brake (TVMRB) was successfully made using the QFD method. Torque characteristics are determined by analysis of magnetic flux density, theoretically, by 3D simulation, and by using Ansys Maxwell experimentally. For consideration, the analysis was carried out with fluid gap variations (0.5 mm, 0.75 mm, and 1 mm) and current variations (0.5–2 A with 0.5 A increments). As a result, ignoring the leakage of MR fluid (MRF), at a constant rotation of 10 rpm, the smallest torque of 6.14 Nm was obtained at the fluid gap variation of 1 mm and input current of 0.5 A, whereas the largest torque was 46.71 Nm at the fluid gap variation of 0.5 mm and input current of 2 A. Apart from torque, this article will also discuss other brake performances in the form of operational range and power consumption. Finally, the structure of the TVMRB design is compared with other designs presented in the House of Quality (HOQ).

Optimal Design and Control Performance Evaluation of a Magnetorheological Fluid Brake Featuring a T-Shape Grooved Disc

“…The performance of MR fluid is examined by the amount of developed shear stress (𝜏) once the excitation coil is electrically supplied. Shear stress in the MR fluid depends on the magnetic field (𝜏 𝑀 ) with the least squares method of the quartic polynomial function based on the magnetic field density of MR fluid [28]: it is expressed as follows. During the material assigning of MR brake components in COMSOL, B-H curves of steels are used instead of the dimensionless relative permeability to determine the degree of magnetization passed through the stator and disc.…”

“…The performance of MR fluid is examined by the amount of developed shear stress (τ) once the excitation coil is electrically supplied. Shear stress in the MR fluid depends on the magnetic field (τ M ) with the least squares method of the quartic polynomial function based on the magnetic field density of MR fluid [28]: it is expressed as follows.…”