From analysis to synthesis of vehicle suspensions: The CRONE approach

This paper deals with a new approach to analyse the influence of suspension on dynamic behaviour of vehicle and to synthesise the force-displacement transmittance of suspension. From a half-car model with four degrees of freedom, it is shown how the design of suspension, which is a vibration isolation problem, can be transformed into a synthesis of a robust control law of a multivariable uncertain plant, which is an automatic control problem. The analysis is based on the Gershgorin theorem and on the small gains theorem. The synthesis is based on the second generation CRONE control. That is why the suspension obtained from this approach is called CRONE suspension. To evaluate performance, a traditional suspension is used for comparison. The CRONE suspension leads to a better comfort and a better road holding ability. The time responses, for various values of the vehicle load, reveal a great robustness of the stability degree through the constancy of the damping ratio in the time domain.