Enhanced Braking Performance by Integrated ABS and Semi-Active Damping Control.

This paper is on focused on the optimisation of the braking process integrating Antilock Braking System (ABS) and Continuous Damping Control (CDC).Strategies for reducing the braking distance derive from theoretical approaches. These strategies deal with sharing information between ABS and CDC in order to improve the slip-control quality and adjusting braking torque(ABS) and / or wheel load (CDC) coordinately. Quantities which influence the amount of the mean braking force and therefore the braking distance are identified methodically, regarding a standard control loop. Furthermore the influence of the time course of wheel load on the braking process is discussed. In the second section of this paper, experimental results of straight-line ABS-braking tests for two methodically identified strategies are discussed. The results of the first experiments show the influence of passive damper settings (hard, soft) and the Mini- Max damping control on the braking distance for various braking conditions (dry and wet roads, flat and uneven roads). The MiniMax damping control aims for reduced body induced slip oscillations that usually disturb standard ABS-control. This damping control reduces the braking distance significantly in a statistical manner. The second experiment has been performed with a modified ABS which takes into account the information of the dynamic wheel load (due to pitching and lifting) additionally for the calculation of the braking force operation point. It is shown that the braking force operation point changes more, if dynamic wheel load information is implemented in ABS-control. Indeed the amount of modulated braking force operation point due to pitching or lifting is too small with respect to the demand, so further modifications are necessary. Finally an outlook on the next steps for improving the braking process by integrated ABS and Continuous Damping Control is given. The full text of this paper may be found at: http://www-nrd.nhtsa.dot.gov/pdf/esv/esv21/09-0204.pdf For the covering abstract see ITRD E145407.