ON THE QUESTION OF BRAKING ARTICULATED BUSES

2021 ◽  
pp. 10-18
Author(s):  
Volodymyr Sakhno ◽  
Volodymyr Poliakov ◽  
Dmytro Yaschenko ◽  
Oleksii Korpach ◽  
Denis Popelysh

The safe movement of a car and a road train is largely determined by its braking properties. The nature of the movement of the road train is fundamentally different from the movement of a single car. The difference can be explained by the presence of additional forces arising in the articulation of the links of the vehicle, as well as forces and moments acting on its individual links and the movement of the vehicle as a whole. Their effect is especially noticeable when braking a road train, which may be accompanied by folding links and loss of stability of the vehicle. As a result of the study, the optimal values of the brake force distribution coefficients for a fully loaded articulated bus are obtained, which provide both high braking efficiency and the stability of the articulated bus (AВ) during braking. The coefficients are determined taking into account the design features of the brake mechanisms and their geometric dimensions, providing the required braking performance. For the selected values of the braking force distribution coefficients along the axes of the AВ and the coefficients that take into account the design features of the braking mechanisms and their geometric dimensions, the braking distance during braking by the main or working braking system and the spare one satisfy the requirements of regulatory documents. With the selected asynchronous response of the brake drives of the bus and trailer, the steady deceleration of the АВ is slightly less than the standard.

2021 ◽  
Vol 1203 (3) ◽  
pp. 032085
Author(s):  
Andrej Haring

Abstract Alingment of braking performance of truck trailer is an important parameter that affects its braking stability. This shows particular in critical situations or during braking on a surface with reduced adhesion. Alingment of braking performance can be automatic, which is one of quality of electronical brake systems. Further on, can be forcible, which is being executed during service a diagnostic work.This contribution is focused on analysis alingment of braking performance. Describing technical conditions, internal and external factors which affect it. Due to magnitude of this problematics, is in this article evaluated the optimization of braking affects truck trailers in the start-up phase. The analysis of the process – start-up braking effect has justification from the reason, that has primary influence on the stability truck trailer during braking and this can be the cause of collision situations or also traffic accidents. The parameter of alingment of braking performance has a primary influence on the braking stability of the truck trailers, which significantly affects road safety and is also important for the economy of the truck trailers. your abstract here… The abstract should include the purpose of research, principal results and major conclusions. References should be avoided, if it is essential, only cite the author(s) and year(s) without giving reference list. Prepare your abstract in this file and then copy it into the registration web field. Braking distance is an important factor in the road construction. Therefore, it must be taken into account when designing these buildings.


Author(s):  
Akhil Challa ◽  
K. B. Devika ◽  
Shankar C. Subramanian ◽  
Gunasekaran Vivekanandan ◽  
Sriram Sivaram

Abstract Wheel lock is an undesired phenomenon in Heavy Commercial Road Vehicles (HCRVs) and wheel slip control within a desired range is of crucial importance for stable and effective braking. This study proposes a framework to distribute brake force dynamically between the front and rear wheels, primarily to avoid instability by preventing wheel lock. Further, it ensures the maximum utilization of the available traction force at the tire-road interface that varies during the course of braking due to factors like load transfer. Wheel slip regulation provides an approach to maximize braking performance that subsumes the effects of varying road, load and braking conditions that occur during vehicle deceleration. The methodology proposed consists of a wheel slip controller that calculates the required brake force distribution parameters, which are then provided to the brake controller for control action. Sliding mode control was used because of the nonlinear nature of the longitudinal vehicle dynamic model considered and for robustness towards different parameter variations. The algorithm was implemented on a Hardware-in-Loop test setup consisting of a pneumatic air brake system, interfaced with IPG-TruckMaker® (a vehicle dynamic simulation software), and co-simulated with MATLAB-Simulink®. It was found that this algorithm improved the braking performance of a HCRV both in terms of stopping distance and vehicle stability.


2021 ◽  
pp. 3-6
Author(s):  

To ensure optimal braking performance, i.e. minimum braking distance while maintaining the stability of the car at the limit of controllability, anti-lock systems are currently installed on cars. The relative fraction of the rest friction in the contact spot, which is used to form the longitudinal reaction of the support surface at the appropriate value of the slip coefficient, in relation to the total fraction of the rest friction in the contact spot is a constant value for any type and condition of the road surface. The coefficient of adhesion in physical essence is the coefficient of friction at rest. The proposed device for determining the coefficient of adhesion of a tire simulator with a flat horizontal support surface will simplify the design and increase the measurement accuracy. Keywords: coefficient of adhesion, a device for determining the coefficient of adhesion, a device


Author(s):  
Jonathan Nadeau ◽  
Philippe Micheau ◽  
Maxime Boisvert

Within the field of electric vehicles, the cooperative control of a dual electro-hydraulic regenerative brake system using the foot brake pedal as the sole input of driver brake requests is a challenging control problem, especially when the electro-hydraulic brake system features on/off solenoid valves which are widely used in the automotive industry. This type of hydraulic actuator is hard to use to perform a fine brake pressure regulation. Thus, this paper focuses on the implementation of a novel controller design for a dual electro-hydraulic regenerative brake system featuring on/off solenoid valves which track an “ideal” brake force distribution. As an improvement to a standard brake force distribution, it can provide the reach of the maximum braking adherence and can improve the energy recovery of a rear-wheel-drive electric vehicle. This improvement in energy recovery is possible with the complete substitution of the rear hydraulic brake force with a regenerative brake force until the reach of the electric powertrain constraints. It is done by performing a proper brake pressure fine regulation through the proposed variable structure control of the on/off solenoid valves provided by the hydraulic platform of the vehicle stability system. Through road tests, the tracking feasibility of the proposed brake force distribution with the mechatronic system developed is validated.


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