Design of magnetorheological damper with short time response

Abstract

For efficient fast control of suspension systems with magnetorheological dampers controlled by semi-active algorithms, the time response of the magnetorheological damper is one of the most important parameters which influences the performance of the suspension system. The time response of commercial magnetorheological dampers with common controllers is in the range of tens of milliseconds, which is too long for efficient real-time control of car suspension. This article describes the ways how to design magnetorheological damper with short response time. First part describes the elimination of long time response caused by high inductance of electrical circuit of magnetorheological damper using current controller. The second part describes elimination of long time response caused by eddy currents which are induced in the magnetic circuit of magnetorheological damper. The new piston of the magnetorheological damper is designed from material with high relative permeability but low electrical conductivity (ferrite). The time responses of magnetic induction and damper forces were measured and compared to original commercial Delphi damper. Results showed rapid improvement in time response when the current controller is used and when the piston is constructed from ferrite materials.

Magnetorheological fluid seal with minimum friction torque

“…2 left, number 1. The second motivation to use MRFs is in MR devices, as magnetorheological damper (Kubík et al, 2017;Strecker et al, 2015) or clutch (Imaduddin et al, 2015),because the same fluid is used for damping and sealing at the same time.…”

Transient Magnetic Model of Magnetorheological Damper and Its Experimental Verification

“…The response times of published designs of MR dampers are in the range of 20-100 ms [1], [3], [4]. From the existing literature, it can be assumed that the response time of MR damper has three sources [5], [6]: inductance of MR damper coil (response time of exciting current), response time of MR fluid, eddy currents in the coil core (response time of magnetic field in the active zone). The response time of MR fluid was estimated in the range of 0.45-0.6 ms by Goncalves [7].…”

“…Yang [1] published his findings that the use of a suitable current controller can significantly reduce the response time of exciting current. Strecker [5] stated that the response time of exciting current can be reduced to 1 ms. Eddy currents in the magnetic circuit create a time lag between the course of electric current and the course of MR damping force [8]. These currents produce a magnetic flux which flows in the opposite direction to the magnetic flux in the magnetic circuit.…”

“…One of the methods how to select the suitable material and the geometry of MR damper is to use a magnetic simulation. According to the available information, only Naoyuki [9] and Strecker [5] dealt with the magnetic modelling of eddy currents in the magnetic circuit of magnetoreological devices. However, in their contribution, this issue was solved only marginally.…”

“…5). The current controller was made by Strecker [5] and controlled by the Arduino system, which was switched between the maximum and zero current in the coil and, vice-versa, with the frequency of 2 Hz. fig.…”