Survey on Modelling and Techniques for Friction Estimation in Automotive Brakes

Abstract

Abstract:The increased use of disc brakes in passenger cars has led the research world to focus on the prediction of brake performance and wear under different working conditions. A proper model of the brake linings' coefficient of friction (BLCF) is important to monitor the brake operation and increase the performance of control systems such as ABS, TC and ESP by supplying an accurate estimate of the brake torque. The literature of the last decades is replete with semi-empirical and analytical friction models whose derivation comes from significant research that has been conducted into the direction of friction modelling of pin-disc couplings. On the contrary, just a few models have been developed and used for the prediction of the automotive BLCF without obtaining satisfactory results. The present work aims at collecting the current state of art of the estimation techniques for the BLCF, with special attention to the models for automotive brakes. Moreover, the work proposes a classification of the several existing approaches and discusses the relative pro and cons. Finally, based on evidence of the limitations of the model-based approach and the potentialities of the neural networks, the authors propose a new state observer for BLCF estimation as a promising solution among the supporting tools of the control engineering.

A Sliding-Mode Virtual Sensor for Wheel Forces Estimation With Accuracy Enhancement via EKF

“…In fact, the mechanical/hydraulic transfer of power to the wheels is affected by several external agents, such as temperature, aging, malfunctioning, etc. [26]. Note that, the form in which (2) is expressed is such that, if a device for the estimation of ∆T w,ij is introduced, in practice all matched uncertainties affecting the model will be compensated as if they were a unique uncertain term, including also parametric uncertainties.…”

Estimation of Power Dissipation in Disc Brakes and Tires for Motion Control Applications in Electric Vehicles

“…General remarks In the last years, the state observation technique has been largely applied in the automotive field as a valid substitute to the model-based approach. [8]: the models are incapable to rightly render the complex wear phenomena occurring in the contact zone and unreliable when the plant characteristics change due to brake wear itself or in case of replacement with aftermarket brake linings and owing to the variation in the weather conditions. The state observer proposed by the same authors in a previous work [15] has been herein employed for the estimation of the dissipated power in brakes and tires.…”

“…With regard to this latter, the virtual sensor estimates the tires longitudinal forces by using the measured longitudinal acceleration in accordance with (8) and 9:…”

“…The literature lacks recognised approaches that depict the wear and PM formation due to difficulties emerging from attempts intended to identify analytical correlations [8]. Most of the literature instances refer to laboratory analysis and do not address the emission in real world environment [9].…”

Design of large mechanical transmission system based on finite element analysis

“…However, the computational simulation is not as mature as the latter two, and its research and application are still in the initial stage. A finite element simulation model of prediction precision and confidence is crucial [7]. Therefore, in order to improve the accuracy of the finite element model, the finite element model updating technology has been further developed in the past thirty years.…”