Global active suspensions for high speed and intercity trains

This article deals with a definition of control laws for suspensions elements of railway vehicles in order to increase dynamics comfort and global comfort of the passengers seating in the cars. The control laws have been obtained by usual Optimum Active Control Theory, skyhook and optimum PID algorithms. Simulations and results analysis illustrate and explain the merits of 2 concepts: global active suspensions concept, multilaws concept. The first concept consists in controlling both transversal and vertical motions. The second one has been stated to solve the dilemma of the transversal railway controlled suspensions, which have to reduce acceleration during the straight line portions, and have to center car during curves sections, in order to avoid high level of acceleration when bumpstops are in contact. The final control law is proposed to be calculated as a linear combination of 2 laws (each law having being obtained for a specific criterion: reduction of acceleration or recentring). The weights for the combination are determined by fuzzy logic analysis. Results indicate significant gains for both transversal and vertical motions, for all track design configurations.