Experimental Set-Up with a Linear Motor Drive System for Magnetorheological Dampers Testing

The work deals with the design, realization and functional tests of an experimental set-up equipped with a linear motor drive system. This experimental set-up is used to determine both the mechanical and electrical properties of linear magnetorheological (MR) dampers. The main elements of the experimental set-up are: a Linmot P10-70 linear motor operating with a Servo Drive E1400 controller, a Sensopart RLA50-220 laser triangulation displacement sensor, a ZEPWN CL-14 strain gauge force sensor operating with a CL 100P amplifier, and a power amplifier based on an OPA549 silicon chip. The linear motor allows the damper piston rod to be moved by a maximum of 150 mm. The power amplifier can operate as a controllable current or voltage source, supplying the damper coil. Its maximum output current is 5 A. The power amplifier internal circuits enable simultaneous measurement of both voltage and current. The physical quantities measured at the experimental set-up, i.e., displacement (0 - 220 mm), force (± 5 kN), coil voltage (± 10 V) and current (± 5 A), are converted into voltage signals in the range ± 10 V and fed to an Inteco RT-DAC 4 PCI measurement-control card supported by the MATLAB/Simulink environment. This card simultaneously generates analogue signals representing the set value of the linear drive slider displacement. A commercial MR damper applied in Audi TT passenger cars was used for functional tests carried out on the designed and constructed experimental set-up. The force-displacement and force-velocity characteristics were experimentally determined at constant coil currents. The temperature of both the stand elements and tested damper was also determined using a FLIR E50 thermal imaging camera.