Vladareanu L., Sireteanu T.

A new method of real time control and the on-line monitoring of the trial stand of Magnetorheological Fluid Damper (MRFD) Control Systems are presented. This allows the generating of the force-movement work behaviour and of the force-velocity hydraulic behaviour for circular movements done with a crank mechanism. The automation system ensures the adjusting of the circular movement’s amplitude and frequency so that it would cover the entire range of applications necessary to testing for the semi-active damper control. A frequency converter with vector and flux control allows the velocity adjusting a wide range and high precision for a prescribed velocity. The damping force and the movement are quasi-simultaneously measured through the two multiplexing signals of the programmable logical controllers (PLC) central unit. The analytical model, a numerical simulation and the experimental results for the implementation of various semi-active control systems with MRFD by using PLCs are presented. An analytical model of MRFD of modified Bouc-Wen type by an inverse method based on experimental data obtained on a damper testing rig is implemented. The damping force variation obtained through the implementation of various control strategies is compared with that predicted by the analytical model. The PLC control system in a distributed and decentralized structure performs the data acquisition with 12 bits resolution for 8 inputs, data processing by specialized software and provides the 4 output control voltage signals to control in real time the MRFD force via a voltage – current driver. The PLC software allows the control voltage synthesis according to the analytical model developed off-line. The experimental and predicted results are in good agreement, showing the possibility of practical implementation of semi-active control strategies with MRFD, by using PLCs. The developed method is also useful for the validation of analytical models developed to portray the dynamic behaviour of MRFDs.