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This paper presents the testing of a Magnetorheological brake (MRB) in the braking system of a vehicle. Two techniques are used to determine the capability of the brake system which are the simulation via Matlab Simulink Software and experimental study by using a quarter vehicle test rig. A Proportional-Integral-Derivative (PID) is employed as a wheel speed control as well as to enforce the MRB to produce the required braking torque need by a vehicle. A dynamic test, namely sudden braking test is performed in three rotational speed conditions which are from 127.5 rad/s (1200 rpm) to 31.42 rad/s (300 rpm), 52.37 Rad/s (500 rpm) and 73.31 rad/s (700 rpm) in two different wheel load which are 10 kg and 15 kg, respectively. The behaviours to be assessed are wheel speed response and brake torque produced by the MRB. From the observation, it is concluded that the capability of the MRB in providing the required brake torque is promising and harmony between simulation and experimental response.

Magnetorheological (MR) damper as a semi-active system for a vehicle suspension is simulated in this study. The proposed design of Magnetorheological (MR) valve consists of meandering flow channel or gaps that fixed in the piston of the damper. The focus of this study is to estimate the performance of proposed MR valve based on actual front suspension parameter of a vehicle. Annular and radial gaps are combined to produce an MR valve with meandering fluid flow path. Furthermore, the damper is filled with Magnetorheological (MR) fluid to energize the damper under the presence of magnetic fields. The magnetic flux density within each gap is obtained via the Finite Element Method Magnetics (FEMM) software. Therefore, the yield stress of MR fluid and magnetic flux relationships both can be predicted. The present paper shows a reduction in pressure drop when the thickness of each gap is increased. Pressure drop is closely affected by the fluid flow rate that enters each gap. This means that the lower flow rate increases the pressure drop of MR valve at various current.