LQG-control of active suspension considering vehicle body flexibility

This work presents preliminary results from a research about active suspension control regarding vehicle body flexibility using LQG-LTR approach. The vehicle model includes three elastic modes, but only the first one is used in control system design. The guideway irregularities are described by their power spectral density function. The inputs are the active suspension forces, and two different choices of measured values are considered, the secondary suspension excursions, and the absolute velocities of bogies and vehicle body. The LQG-LTR method yields an inverse of the plant, so transmission zeros must have negative real parts, but with those measurements this condition does not hold. A modified system model that includes integrators at the plant inputs satisfy the transmission zero condition, and allow the attainment of better ride comfort.