Reduktion von Bremskraftschwingungen mithilfe reibkraftgeregelter Bremsen

  • Reduction of brake force oscillations using friction force controlled brakes

Hirtz, Matthias; Murrenhoff, Hubertus (Thesis advisor); Markert, Bernd (Thesis advisor)

Düren : Shaker Verlag (2021)
Book, Dissertation / PhD Thesis

In: Reihe Fluidtechnik. D 106
Page(s)/Article-Nr.: 1 Online-Ressource : Illustrationen, Diagramme

Dissertation, RWTH Aachen University, 2020

Abstract

The research presented in this work analyses two friction force-controlled brakes regarding their ability to influence and actively reduce occurring brake force oscillations. Based on the state of the art, the prototype of a self-energized electrohydraulic brake (SEHB) and the corresponding test bench are introduced. Brake tests carried out prove the occurrence of the vibration phenomenon of brake judder. A detailed 1D-simulation model of the SEHB reproduces the vibration behaviour of occurring forces and has been validated by measurement results. Both measurements and simulation results show that the compensatory capacity of the prototype is limited regarding friction-induced vibrations. In the following, the simulation model is used to derive innovative control structures, analyse the results and validate them on the test bench. A derivative feedforward control successfully compensates frictional force oscillations. Observed vibration amplitudes can be actively reduced up to 86 % depending on the brake disc speed by adjusting the actuation of the SEHB both at constant speeds and when driving through speed ramps. Subsequently, the work concentrates on a hydraulic-mechanically controlled brake, which is characterized by its simple retrofittability into an uncontrolled brake that has already been used in practice. A comprehensive 1D-simulation model of the brake system is followed by an analysis and optimization of the compensating capacity of brake force oscillations. Compensation rates of almost 90 % can also be determined for the hydraulic-mechanically controlled brake in wide operating ranges. Overall, the results of the work show the promising potential of friction forcecontrolled brakes regarding the compensation of brake force oscillations and the phenomenon of brake judder in particular. The further development of such brake systems up to their industrial implementation therefore appears promising, as these brake systems are able to meet increased demands for the required performance, sensitivity and reproducibility of braking processes.

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