A comprehensive analysis of the response time of MR dampers

Abstract

The primary purpose of this paper is to provide a comprehensive review on the response time of magnetorheological (MR) dampers. Rapid response time is desired for all real-time control applications. In reviewing the literature, a detailed description of the response time of semi-active dampers is seldom given. Furthermore, the methods of computing the response time are not discussed in detail. The authors intend to develop a method for the definition and the experimental determination of the response time of MR dampers. Furthermore, parameters affecting the response time of MR dampers are investigated. Specifically, the effect of operating current, piston velocity, and system compliance are addressed. Because the response time is often limited, not by the response of the fluid itself, but by the limitations of the driving electronics and the inductance of the electromagnet, the response time of the driving electronics is considered as well. The authors define the response time as the time required to transition from the initial state to 95% of the final state. Using a triangle wave to maintain constant velocity across the damper, various operating currents ranging from 0.5 to 2 A were applied and the resulting force was recorded. The results show that, for a given velocity, the response time decreases as the operating current increases. Results for the driving electronics show the opposite trend: as current increases, response time increases. To evaluate the effect of piston velocity on response time, velocities ranging from 0.1 to 4 in s −1 were tested. The results show that the response time decreases exponentially as the velocity increases, converging on some final value. Further analysis revealed that this result is an artifact of the compliance in the system. To confirm this, a series of tests was conducted in which the compliance of the system was artificially altered. The results of the compliance study indicate that compliance has a significant effect on the response time of the damper.

Effect of the Volume of Magneto-rheological Fluid on Shear Performance

“…It is a hydrocarbon-based suspension of around 30% (volume) iron particles. Its density is 3.06 g/cm 3 . The size and shape distributions of the magnetisable particles were examined by scanning electron microscopy (SEM).…”

“…As to the typical shear MRF dampers, the working cylinder is full of MR fluid [3]- [5], during the working process of dampers, the produced leakage will be unavoidable and will shorten the life of the damper, especially to the disk-disk shear dampers, as well as weaken the MR effect (mainly in shear performance).…”

“…However, the previous studies focused on the measurement of the characteristics or new designs of the MRF dampers [3], the influence of volume on the shear performance has been seldom investigated. Besides, our early works have mentioned the effect of volume on the characteristics of MR [6].…”

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].…”

Perancangan Rem Linier Memakai Fluida MR dengan Kendali Arus Listrik Berbasis Fungsi Linier

“…Sifat-sifat dan aplikasi dari fluida MR komersial telah dipublikasikan oleh peneliti lain terdahulu [6]. Tanggapan waktu damper MR telah dikaji melalui eksperimen [7]. Perkembangan berikutnya adalah pengembangan busa MR untuk damper [8], [9].…”