EFFICIENT CHASSIS APPLICATION WITH INTEGRAL CONTROLLER, VIRTUAL METHODOLOGY

The driving dynamics genes of an Audi are based on a passive base chassis and are essentially defined by the functional software of the active chassis systems. Applying brand-specific driving characteristics to the increasing number of vehicle models and variants forming part of the company’s product strategy entails increasing commitment to chassis tuning. New electric drivetrains are adding to the complexity. The aim at Audi is to manage this additional complexity in the product creation process with reduced resources.

- DR.-ING. ADRIAN MIHAILESCU, DR.-ING. INGO SCHARFENBAUM, ULI SCHAAF, DR.-ING. CHRISTIAN SCHIMMEL

Developing the concept and functionality is a basic building block at the start of a project. The decision to develop a centralised integral controller was taken at an early stage. This article focusses on the last three years prior to Start of Production (SOP). In order to master the complexity of chassis control systems and their interactions within the constraints of the available resources, it was essential for three disciplines to work together.

At the beginning of this development phase, functional development predominates, adding new functions and optimising existing ones. Virtual methodology is applied to evaluate functional changes prior to implementing them in the vehicle and provides the initial basis for the application of characteristic features. Test drives incorporating the applied characteristics assure attainment of the project-specific goals, as well as checking the configuration at all relevant driving dynamics operating points. The following sections describe the individual disciplines and their interaction.

INTEGRAL CONTROLLER

The lateral dynamics functions of the integral controller are integrated into the central chassis control unit, the second-generation EFP electronic chassis platform in the form of a software module [1]. The control unit computes the functions for all the chassis control systems and provides a unified development environment across all the systems. The data from the connected sensors is checked for plausibility and processed centrally before being merged into the driving state detection function. The integral controller module computes coordinated actuator actions from the driving state data and sends the necessary signals to the available chassis control systems, 1.