Yes / This paper presents a simulation study into the characteristics of a vehicle experiencing steering drift under straight line braking. Simulation modelling has been performed using a multi-body dynamics analysis based on a model of an actual vehicle. Front and rear suspension parameters have been modelled as rigid links joined with flexible bushes so as to assess their effect on a vehicle while braking. Suspension geometry and alignment settings, which define characteristic responses such as lateral acceleration, yaw velocity, toe, and caster angles of a vehicle in a transient manoeuvre, are primary to a vehicle¿s directional stability. Any symmetric inconsistencies in these settings will potentially affect a vehicle¿s performance. The findings from this research have increased the understanding of the causes of steering drift during braking conditions.

No / In this paper, a similarity concept is proposed to improve student understanding on difficult and complicated engineering theory. The planned application of this approach is for the Transportation Studies module (CSE6004-A) at School of Engineering, University of Bradford, United Kingdom. In the module, noise induced by road transport and vehicles are taught in depth, where the proposed teaching method will be applied to aid student understanding on the numerical concept of the vibration effect and noise on vehicle braking system. As part of the module planning, the full numerical solution of brake judder/vibration effect, which includes shaking (forced vibration) and nibbling (torsional vibration) effects will be introduced to students where similarity concept will be adapted in its teaching. The successfully applied concept will also be able to utilize by other engineering teaching and modules.

Although many studies have investigated accelerator/brake pedal placement in terms of the time needed to move the foot from the accelerator to the brake during emergency braking (i.e. movement time), none have as yet specifically addressed the issue of pedal actuation errors. The primary purpose of the present study was to determine what types of errors (if any) occur, to document the frequency with which various categories of error occur, and to determine whether the different types of error are configuration-dependent. To accomplish this, the foot movements of subjects were observed and recorded while they performed a variety of driving tasks in an automobile simulator. Subjects drove the simulator on four separate occasions. For each session the simulator was modified to represent one of four different pedal, floor, and seating geometries present in actual automobiles. / Master of Science

The goal of this experiment was to determine what if any effect two different types of warnings have the brake reaction time of distracted commercial motor vehicle operators. The warning conditions were: No Warning, Auditory Tire Skid Warning, and One Second Brake Pulse Warning. Each participant was distracted via a distracter task during the experiment. As the participants were distracted, an obstacle was launched out into their forward path. Each participant received his/her appropriate warning, according to what condition they were placed, when the obstacle entered their headway. It was determined that the Auditory Tire Skid Warning aided in decreasing the movement times, while the One Second Brake Pulse Warning aided in decreasing the number of collisions with the barrels and speed at contact with the barrels. / Master of Science

A vehicle has several rotating components such as a traction electric motor, the driveline, and the wheels and tires. The rotating inertia of these components is important in vehicle performance analyses. However, in many studies, the rotating inertias are typically lumped into an equivalent inertial mass to simplify the analysis, making it difficult to investigate the effect of those components and losses for vehicle energy use. In this study, a backward-tracking model from the wheels and tires to the power source (battery or fuel cell) is developed to estimate the effect of rotating inertias for each component during propulsion and regenerative braking of a vehicle. This paper presents the effect of rotating inertias on the power and energy for propulsion and regenerative braking for two-wheel drive (either front or rear) and all-wheel drive (AWD) cases. On-road driving and dynamometer tests are different since only one axle (two wheels) is rotating in the latter case, instead of two axles (four wheels). The differences between an on-road test and a dynamometer test are estimated using the developed model. The results show that the rotating inertias can contribute a significant fraction (8 -13 %) of the energy recovered during deceleration due to the relatively lower losses of rotating components compared to vehicle inertia, where a large fraction is dissipated in friction braking. In a dynamometer test, the amount of energy captured from available energy in wheel/tire assemblies is slightly less than that of the AWD case in on-road test. The total regenerative brake energy capture is significantly higher (> 70 %) for a FWD vehicle on a dynamometer compared to an on-road case. The rest of inertial energy is lost by inefficiencies in components, regenerative brake fraction, and friction braking on the un-driven axle. / Master of Science

The diploma thesis deals with the issue of braking trucks at different loads. The theoretical part defines the basic construction of trucks, truck brakes, the braking process and the factors that affect braking, braking deceleration, and legislative requirements for truck brakes. The practical part describes the course of experimental measurements, the use of the technique, the place of measurement, atmospheric conditions and used trucks. At the end of the work, based on experimental measurements, the obtained values of braking deceleration of trucks are evaluated.

This work is engaged in the confrontation of the existing braking system of Formula SAE project. From made confrontations is selected the best solution and make his dimension and own construct design. It is verify through analyse of tension and analyse of heat transfer.

This thesis is devoted on passenger car tyres. Theoretical part covers description of production, construction and tyre parameters. Practical part is comprised experimental measurement of influence of tread grooves depth on achievable vehicle deceleration. First, it is focused on preparation conditions of measurement, with subsequent processing and evaluation of the data obtained.

The application of Model Reference Adaptive Control (MRAC) for train dynamic braking is investigated in order to control dynamic braking forces while remaining within the allowable adhesion and coupler forces.  This control method can accurately determine the train braking distance.  One of the critical factors in Positive Train Control (PTC) is accurately estimating train braking distance under different operating conditions.  Accurate estimation of the braking distance will allow trains to be spaced closer together, with reasonable confidence that they will stop without causing a collision.  This study develops a dynamic model of a train consist based on a multibody formulation of railcars, trucks (bogies), and suspensions.   The study includes the derivation of the mathematical model and the results of a numerical study in Matlab.  A three-railcar model is used for performing a parametric study to evaluate how various elements will affect the train stopping distance from an initial speed.  Parameters that can be varied in the model include initial train speed, railcar weight, wheel-rail interface condition, and dynamic braking force.  Other parameters included in the model are aerodynamic drag forces and air brake forces. An MRAC system is developed to control the amount of current through traction motors under various wheel/rail adhesion conditions while braking.  Minimizing the braking distance of a train requires the dynamic braking forces to be maximized within the available wheel/rail adhesion.  Excessively large dynamic braking can cause wheel lockup that can damage the wheels and rail.  Excessive braking forces can also cause large buff loads at the couplers.  For DC traction motors, an MRAC system is used to control the current supplied to the traction motors.  This motor current is directly proportional to the dynamic braking force.  In addition, the MRAC system is also used to control the train speed by controlling the synchronous speed of the AC traction motors.  The goal of both control systems for DC and AC traction motors is to apply maximum available dynamic braking while avoiding wheel lockup and high coupler forces.  The results of the study indicate that the MRAC system significantly improves braking distance while maintaining better wheel/rail adhesion and coupler dynamics during braking.  Furthermore, according to this study, the braking distance can be accurately estimated when MRAC is used.  The robustness of the MRAC system with respect to different parameters is investigated, and the results show an acceptable robust response behavior. / Ph. D.

In this thesis project, brake performance of heavy vehicles is improved by the development of new wheel-based functions for a longitudinal slip control braking system using novel Fast Acting Braking Valves (FABVs). To achieve this goal, Volvo Trucks' vehicle dynamics model has been extended to incorporate the FABV system. After validating the updated model with experimental data, a slip-slope based recursive least squares friction estimation algorithm has been implemented. Using information about the tire-road friction coefifcient, the sliding mode slip controller has been made adaptive to different road surfaces by implementing a friction dependent reference slip signal and switching gain for the sliding mode controller. This switching gain is further optimized by means of a novel on-line optimization algorithm. Simulations show that the on-line friction estimation converges close to the reference friction level within one second for hard braking. Furthermore, using this information for the optimized controller has resulted in reduction of braking distance on most road surfaces of up to 20 percent, as well as in most cases a reduction in air usage.