Affiliations: [a] FME Institute of Machine and Industrial Design, Brno
University of Technology, Brno, Czech Republic
Correspondence:
[*]
Corresponding author: Z. Strecker, FME Institute of Machine and
Industrial Design, Brno University of Technology, Technická 2, 616 69
Brno, Czech Republic. Tel.: +42 0607 290 557; E-mail: strecker@fme.vutbr.cz
Abstract: Magnetorheological dampers seem to be suitable for the adaptive car
suspension systems. For proper operation of the semi-active algorithms
(skyhook, groundhook), the force response of the damper must be fast enough. In
this paper, the response time of the Delphi vehicle MR damper is examined and
the sources of the overall force time response on the control voltage are
discussed. One of the main sources of the response time seems to be
electro-magnetic circuit of the MR damper. A principle of an optimal controller
for reducing response of the coil's current on the control voltage is designed.
However, the measured overall force time response with fast current controller
was not reduced as expected. Therefore, a FEM simulation of the magnetic
circuit was made. It shows that after an optimization of the current
controller, eddy currents in the coil's core cause long time response and
therefore they are the limiting factor of the response time of the MR damper.
These simulations were verified by the measurements and some recommendations
about improving the pistons construction are given at the end.
Keywords: Magnetorheological damper, MR, time response, pulse-width modulation, eddy current
