Improvement of Control Performance for Active Vibration Control of Railway Vehicle : 2nd Report, Adoption of g Synthesis for Improving Robustness against Mass Variation

In recent years, active suspensions have been studied for improving the ride quality of railway vehicles. In the active vibration control, it is important that the control system be robust against mass variation of the car body due to the varying number of passengers. However, it was indicated that LQG controller can become unstable when the body mass is lightened. Although H_∞ controller is stable against the mass variation, it is expected that the adoption of μ synthesis can improve the control performance still more. In this paper, the car body mass variation is considered in the linear state space representation of control object as parametric uncertainty, so that the μ synthesis can be adopted for the controller design. The control performance of the μ controller is investigated with a 3 d. o. f. half-vehicle model experimentally. As a result, it is shown that the μ controller improves the deterioration due to the car body mass reduction, and that it provides better control performance using a frequency dependent weighting function more than using constant weightings for the uncertainty of the mass variation