Optimized Braking System Sizing by Means of a Parametric 1D Brake Model 2019-26-0355
This paper presents a methodology that incorporates a 1D (non-geometric) brake model, together with conventional vehicle tests, into the solution of problems associated with the sizing of a braking system.
The 1D tool is aimed at predicting the main braking attributes,such as pedal feel or thermal capacity under repeated snubs, and the fulfilment of the legislative requirements —service, emergency and parking brake performance. The model recreates a parametric brake system, and thus allows engineers to understand the impact a parameter (e.g. a specification) might have on the overall performance when it is altered. This calculation provides valuable assistance when sizing a braking system.
The vehicle under study, an off-road car, suffered from unacceptable pedal feel —deemed as spongy— and, most importantly, did not satisfy the requirements laid down in AIS 150 for the secondary braking system. The methodology presented is divided into three phases. In the first, vehicle and brake specifications were gathered in order to model them through the 1D tool; once the simulation was completed, prediction results were correlated using the previously measured vehicle test data. The second phase consisted of modelling the available replacementoff-the-shelf components, thus reducing costs and getting shorter lead times; the outcome was a gap analysis, i.e. exploring the relative impact that each modified component had on the critical attributes. Finally, during the last phase, the new components were tested on the vehicle; newly-obtained evidence was compared against the baseline experimental results in order to check whether the targeted improvements were successfully met.
The methodology presented succeeds in reducing the number of vehicle test iterations throughout the brake sizing stage, thus being more cost-effective and less time-consuming than the usual trial and error approach to select the off-the-shelf components available from suppliers.