A COMPUTER AIDED ENGINEERING APPROACH FOR THE OPTIMAL DESIGN OF AN ACTIVE SUSPENSION SYSTEM

Within companies dealing with the automotive market, and in particular for product designers. the usage of numerical simulations is a well established technique to help achieving faster development cycles. Focusing on the very first phase of the design development chain conceptual (1D) modeling software is better suited. Furthermore considering the multiphysics nature of vehicle subsystems. a multidisciplinary system modeling tool is required. which has to be enriched with optimization capabilities in order to produce a suitable design of complex systems involving multiphysics functionalities (for instance for active safety and energy management). The purpose of this paper is to summarize a procedure that has been applied for the optimal design of an active suspension with hydraulic actuation, governed by a general control strategy based on the sky-hook approach. to be manufactured by Tenneco. A 15 Degrees of Freedom (DOF) vehicle model, built in a commercially available 1D simulation environment, has been validated as a first step towards achieving a good correlation with experimental results obtained on the test tracks. As a next step, the sky-hook based control strategy was implemented to take into account the active behavior of the system, and to define the load profiles actin on the suspension dampers while the vehicle is virtually tested on ride roads Optimization loops were performed in a nested architecture in order to define the optimal gains needed to meet certain performance requirements dictated by the vehicle manufacturer. A detailed model of the damping system was implemented in LMS Imagine.Lab AMESim capturing its multidisciplinary nature including mechanical, hydraulic and electrical aspects. The mission profiles (force-velocity couples at the dampers) were used as input to the simulations to investigate the damping system design parameters considering performance achievement and enemy efficiency goals The results of this project have been used by Tenneco as guidelines for the physical prototype implementation of the active suspension system