USING A LUENBERGER OBSERVER TO ESTIMATE THE PITCHING MOMENT OF THE VEHICLE

Abstract

Motion safety is an extremely important factor in automotive design. There are many solutions that are applied to enhance this feature such as optimizing the structural parameters of the car, using active systems such as braking, suspension, steering... When the vehicle suddenly changes the speed, there will be a change of mass between its axes and cause a moment rotating around the center of gravity of the vehicle. This moment is called the “Pitching moment”. This factor causes the vehicle possibility to be lifted up therefore estimating this moment will help manufacturers figure out solutions the increase vehicle safety. In fact, it is difficult to measure the value of this moment and no sensors can be performed directly in real cars. This paper proposes a new method to estimate the pitching moment by using a Luenberger observer for the ½ vertical half car model. The linear quadratic regulator control theory is also applied to design this observer. The simulation results in time domain with a real car model have shown the efficiency and accuracy of the proposed method with very small signal delay.