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The presented study demonstrates results of experimental investigations of the anti-lock braking system (ABS) performance under variation of tire inflation pressure. This research is motivated by the fact that the changes in tire inflation pressure during the vehicle operation can distinctly affect peak value of friction coefficient, stiffness and other tire characteristics, which are influencing on the ABS performance. In particular, alteration of tire parameters can cause distortion of the ABS functions resulting in increase of the braking distance. The study is based on experimental tests performed for continuous ABS control algorithm, which was implemented to the full electric vehicle with four individual on-board electric motors. All straight-line braking tests are performed on the low-friction surface where wheels are more tended to lock.

Research and development tools for investigations of various facets of braking processes cover three major groups of devices: Dynamometer test rigs: assessment of performance, durability, life cycle and others; Tribometer test rigs: definition of parameters of friction and wear; Hardware-in-the-loop: estimation of functional properties of controlled braking. A combination of the listed devices allows to research complex phenomena related to braking systems. The presented work discusses a novel approach of test rig fusion, namely the combination of a brake dynamometer and hardware in the loop test rig. First investigations have been done during the operation of the anti-lock braking system (ABS) system to demonstrate the functionality of the approach.

The presented research discusses the experimental procedure developed for testing of friction brake systems installed on the modern electric vehicles. Approach of combined experimental technique utilizing hardware-in-the-loop platform and brake dynamometer is introduced. As the case study, an influence of brake lining coefficient of friction fluctuations on the anti-lock brake system (ABS) performance is investigated. The ABS algorithm is represented by the direct slip control aimed to the precise tracking of reference slip ratio by means of electric and friction brake system. Vehicle prototype is represented by RWD electric vehicle with in-wheel motors. Results, representing the investigated phenomenon, are derived using the developed combined test bench. The achieved results give a basis for further extension of standard brake testing procedures.