Real-Time Simulation of Elastokinematic Wheel Suspension Systems
Contact
In the project „Real-Time Simulation of Elastokinematic Wheel Suspension Systems“, real-time capable simulation of vehicle suspension systems with special focus on their elastokinematic properties is researched.
Motivation
Virtual methods gain increasing importance in vehicle development. Components and systems can be designed more efficiently and validated early in the development process. This trend also includes vehicle dynamics development. Here, subjective evaluation of the driving characteristics plays a decisive role. Driving simulators are the key tool for making the driving characteristics tangible without expensive real prototype vehicles. This requires both precise and real-time capable vehicle dynamics models.
Goal
The vehicle suspension system and its elastokinematic design have major influence on the vehicle dynamics. Due to elastokinematic bearings and elasticity of components, additional wheel displacements occur under external loads which superpose the pure kinematic wheel motion. The elastokinematic design of suspension systems aims either to compensate or to exploit these additional wheel displacements to improve ride comfort and driving characteristics. For virtual testing with driving simulators, real-time capable vehicle dynamics models are required. Often, elastokinematic effects are neglected or strongly simplified in vehicle dynamic models to achieve real-time capability. Therefore, the goal of this project is to develop a multibody simulation model for accurate and real-time capable simulation of suspension systems with special focus on their elastokinematic properties.
Approach
The simulation model is based on the methods of elastic multibody simulation. Elasticities of the suspension components are modeled using finite element method. Through linear model order reduction, the number of elastic degrees of freedom is reduced in order to incorporate the elastic bodies in the multibody system. In addition to modal model order reduction methods, modern methods are evaluated. They promise higher accuracy with less degrees of freedom. Elastokinematic bearings are modeled through force elements with nonlinear stiffness and damping characteristics. Stable and computationally efficient time integration of the stiff equation of motion is achieved through special integration methods. The model is implemented in Matlab/Simulink.