Influence on the Dynamic Behavior of Full Car Equipped by Magnetorheological Damper via Switch on/off and h∞ Controller

This paper shows the influence on dynamic behavior of the car when it is equipped with magneto-rheological dampers controlled by a feedback. The feedback is built up in two ways; the first is implemented by a switch on/off control that is characterized by the injection of magnetic field with a constant value. It happens when a certain value of relative speed between the sprung and unsprung mass is exceeded. The second feedback is characterized by the H-infinity control which is based on the relative displacement in order to vary the magnetic field signal in a continuous manner. At the same time the H-infinity control of vehicle is maintained by taking into account the exceeding of speed signal in order to consider the substantial differences with the switch on/off control. These differences are evaluated in terms of relative displacement and speed between the unsprung and sprung mass. The exogenous excitation is the road disturbances which are introduced as a square wave input in order to emulate those that are commonly encountered on the road. All simulations and results are performed by MATLab-Simulink and Mathematica.