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Geometric imperfections on brake rotor surface are well-known for causing periodic variations in brake torque during braking. This leads to brake judder, where vibrations are felt in the brake pedal, vehicle floor and/or steering wheel. Existing solutions to address judder often involve multiple phases of component design, extensive testing and improvement of manufacturing procedures, leading to the increase in development cost. To address this issue, active brake torque variation (BTV) compensation has been proposed for an electromechanical brake (EMB). The proposed compensator takes advantage of the EMB's powerful actuator, reasonably rigid transmission unit and high bandwidth tracking performance in achieving judder reduction.

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.

The paper introduces the results of the development of anti-lock brake system (ABS) for full electric vehicle with individually controlled near-wheel motors. The braking functions in the target vehicle are realized with electro-hydraulic decoupled friction brake system and electric motors operating in a braking mode. The proposed ABS controller is based on the direct slip and velocity control and includes several main blocks for computing of predictive (feedforward) and reactive (feedback) brake torque, wheel slip observer, slip target adaptation, and the algorithm of brake blending between friction brakes and electric motors. The functionality of developed ABS has been investigated on the HIL test rig for straight-line braking manoeuvres on different surfaces with variation of initial velocity. The obtained experimental results have been compared with the operation of baseline algorithm of a hydraulic ABS and have demonstrated a marked effect in braking performance.

This is a errata for 2017-01-2520.

The brake architecture of hybrid and full electric vehicle includes the distinctive function of brake blending. Known approaches draw upon the maximum energy recuperation strategy and neglect the operation mode of friction brakes. Within this framework, an efficient control of the blending functions is demanded to compensate external disturbances induced by unpredictable variations of the pad disc friction coefficient. In addition, the control demand distribution between the conventional frictional brake system and the electric motors can incur failures that compromise the frictional braking performance and safety. However, deviation of friction coefficient value given in controller from actual one can induce undesirable deterioration of brake control functions.

Anti-lock braking functions of electric vehicles with individual wheel drive can be effectively realized through the operation of in-wheel or on-board motors in the pure regenerative mode or in the blending mode with conventional electro-hydraulic anti-lock braking system (ABS). The regenerative ABS has an advantage in simultaneous improvement of active safety, energy efficiency, and driving comfort. In scope of this topic, the presented work introduces results of experimental investigations on a pure electric ABS installed on an electric powered sport utility vehicle (SUV) test platform with individual switch reluctance on-board electric motors transferring torque to the each wheel through the single-speed gearbox and half-shaft. The study presents test results of the vehicle braking on inhomogeneous low-friction surface for the case of ABS operation with front electric motors.

Nowadays there is a tendency to implement various active vehicle subsystems in a modern vehicle to improve its stability of motion, handling, comfort and other operation characteristics. Since each vehicle subsystem has own limits to generate supporting demand, their potential impact on vehicle dynamics should be analyzed for steady-state and transient vehicle behavior. Moreover, the additional research issue is the assessment of total energy consumption and energy losses, because a stand-alone operation of each vehicle subsystem will provide different impact on vehicle dynamics and they have own energy demands. The vehicle configuration includes (i) friction brake system, (ii) individual-wheel drive electric motors, (iii) wheel steer actuators, (iv) camber angle actuators, (v) dynamic tire pressure system and (vi) actuators generating additional normal forces through external spring, damping and stabilizer forces. A passenger car is investigated using commercial software.

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.

Tire modeling plays an important role in the development of an Active Vehicle Safety System. As part of a larger project that aims at developing an integrated chassis control system, this study investigates the performance of a 19” all-season tire on ice for a sport utility vehicle. A design of experiment has been formulated to quantify the effect of operational parameters, specifically: wheel slip, normal load, and inflation pressure on the tire tractive performance. The experimental work was conducted on the Terramechanics Rig in the Advanced Vehicle Dynamics Laboratory at Virginia Tech. The paper investigates an approach for the parameterization of the Dugoff tire model based on the experimental data collected. Compared to other models, this model is attractive in terms of its simplicity, low number of parameters, and easy implementation for real-time applications.