scholarly journals An Overview of Heavy Trucks/Buses Braking Performance

1991 ◽  
Vol 8 (1) ◽  
Author(s):  
Richard M. Ziernicki
Keyword(s):  
Statistical Data ◽  
Vehicle Speed ◽  
Test Results ◽  
Heavy Duty ◽  
Braking Performance ◽  
Emergency Braking ◽  
Heavy Trucks ◽  
Brake Performance ◽  
Drag Factor ◽  
Heavy Duty Vehicles

The writer discusses the performance of heavy duty vehicles during emergency braking. The paper reviews statistical data related to the trucking accidents, and discusses brake performance, tires, and the stopping ability of heavy duty vehicles. Relationships between drag factor, coefficient of friction, vehicle speed, type of tire, road surface, brake design, and brake temperature are discussed. Some of the test results performed on heavy trucks are presented. The discussion is general in order to make the presentation useful both to practicing reconstruction specialists, and to attorneys.

scholarly journals Development and Testing of a Collision Avoidance Braking System for an Autonomous Vehicle

2019 ◽  
Vol 8 (12) ◽  
pp. 703-709
Keyword(s):  
Autonomous Vehicle ◽  
Test Results ◽  
Correct Operation ◽  
Braking Performance ◽  
System Parameters ◽  
Emergency Braking ◽  
Braking System ◽  
Good Consistency ◽  
Main Development ◽  
Outdoor Experiments

The article describes the main development and testing aspects of an emergency braking function for an autonomous vehicle. The purpose of this function is to prevent the vehicle from collisions with obstacles, either stationary or moving. An algorithm is proposed to calculate deceleration for the automated braking, which takes into account the distance to the obstacle and velocities of both the vehicle and the obstacle. In addition, the algorithm adapts to deviations from the required deceleration, which are inevitable in the real-world practice due to external and internal disturbances and unaccounted dynamics of the vehicle and its systems. The algorithm was implemented as a part of the vehicle’s mathematical model. Simulations were conducted, which allowed to verify algorithm’s operability and tentatively select the system parameters providing satisfactory braking performance of the vehicle. The braking function elaborated by means of modeling then was connected to the solenoid braking controller of the experimental autonomous vehicle using a real-time prototyping technology. In order to estimate operability and calibrate parameters of the function, outdoor experiments were conducted at a test track. A good consistency was observed between the test results and simulation results. The test results have proven correct operation of the emergency braking function, acceptable braking performance of the vehicle provided by this function, and its capability of preventing collisions.

Testing and Analysis of Autonomous Emergency Braking Systems Using the Euro NCAP Vehicle Target

2014 ◽  
Author(s):  
Matthew L. Schwall ◽  
John D. Neal ◽  
Charles J. Retallack ◽  
Robert E. Larson ◽  
Graeme F. Fowler
Keyword(s):  
Sensor Data ◽  
Vehicle Speed ◽  
Test Results ◽  
Passenger Cars ◽  
Collision Warning ◽  
Euro Ncap ◽  
Emergency Braking ◽  
Collision Mitigation ◽  
The Subject ◽  
Forward Collision Warning

Passenger cars are increasingly available equipped with Autonomous Emergency Braking (AEB). AEB systems detect likely forward collisions and apply the vehicle’s brakes if the driver fails to do so, reducing vehicle speed in order to mitigate or potentially avoid a collision. The performance of these systems is experimentally evaluated in tests including those specified by the European New Car Assessment Program (Euro NCAP) and by the Insurance Institute for Highway Safety (IIHS). In both of these testing programs the subject vehicle is driven towards a Euro NCAP Vehicle Target, an inflatable device designed to have visual and radar reflective characteristics similar to the rear of a compact car. The results reported by Euro NCAP and the IIHS have revealed significant differences in the AEB test results achieved by various AEB-equipped vehicles. Such differences exist even between vehicles with similar sensing technologies, suggesting that the source of such disparities may be differences in sensor data processing methods or differences in collision mitigation and avoidance strategies. This paper details the performance of AEB as well as Forward Collision Warning (FCW) systems when tested with the Euro NCAP Vehicle Target. These results are analyzed, exploring the differences in the performance of these systems under the test conditions and discussing possible reasons for the observed disparities.

The impact of hybridization, engine combustion method, and energy management system connectivity on heavy-duty vehicle operation

2021 ◽  
pp. 095440702098304
Author(s):  
Carrie M Hall
Keyword(s):  
Real Time ◽  
Energy Management ◽  
High Efficiency ◽  
Fuel Efficiency ◽  
Vehicle Speed ◽  
Heavy Duty ◽  
Wide Range ◽  
Engine Combustion ◽  
The Impact ◽  
Heavy Duty Vehicles

A wide range of strategies for reducing energy consumption from heavy-duty vehicles have been explored from vehicle electrification to real-time vehicle energy management based on vehicle-to-vehicle and vehicle-to-infrastructure communication. Full electrification of heavy-duty vehicles can be challenging due to current limitations on battery energy density. However, hybridization and the implementation of high efficiency engines present other potential near-term solutions. In contrast to many prior studies that have explored the use of one or two of these techniques, this work discusses the combined influence of hybridization level, engine combustion mode, and connected energy management on fuel efficiency in heavy-duty applications. The impact of hybridization in different driving conditions is quantified and the effectiveness of hybrid powertrain structures with different engine combustion strategies is also explored. Utilizing an alternative combustion strategy can improve fuel efficiency by 5% in conventional and mild hybrids but was found to have a more minimal impact in full hybrids. An additional layer of complexity is also introduced when vehicles have some degree of connectivity and this influence on the energy management method is investigated by comparing control approaches which leverage current and future vehicle speed information. Connectivity and the ability to optimize energy production in real-time was found to be essential in uncertain cases and enable improvements in fuel consumption of up to 12% over baseline cases.

Adaptive Continuously Variable Compression Braking Control for Heavy-Duty Vehicles

2002 ◽  
Vol 124 (3) ◽  
pp. 406-414 ◽  
Author(s):  
Maria Druzhinina ◽  
Anna Stefanopoulou ◽  
Lasse Moklegaard
Keyword(s):  
Actuator Saturation ◽  
Adaptive Controller ◽  
Vehicle Speed ◽  
Heavy Duty ◽  
Actuator Dynamics ◽  
Speed Tracking ◽  
Road Grade ◽  
Braking Control ◽  
Variable Compression ◽  
Heavy Duty Vehicles

Modern heavy-duty vehicles are equipped with compression braking mechanisms that augment their braking capability and reduce wear of the conventional friction brakes. In this paper we consider a heavy-duty vehicle equipped with a continuously variable compression braking mechanism. The variability of the compression braking torque is achieved through controlling a secondary opening of the exhaust valve of the vehicle’s turbocharged diesel engine using a variable valve timing actuator. A model reference adaptive controller is designed to ensure good vehicle speed tracking performance in brake-by-wire driving scenarios in presence of large payload and road grade variations. The adaptive controller is integrated with backstepping procedure to account for compression braking actuator dynamics, with observers for various unmeasured quantities and with compensation schemes for actuator saturation. In addition to speed tracking, the vehicle mass and road grade are simultaneously estimated if persistence of excitation-type conditions hold. The final version of the controller is successfully evaluated on a high order crank angle model of a vehicle with a six-cylinder engine.

scholarly journals An Automatic Emergency Braking Model considering Driver’s Intention Recognition of the Front Vehicle

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Wei Yang ◽  
Jiajun Liu ◽  
Kaixia Zhou ◽  
Zhiwei Zhang ◽  
Xiaolei Qu
Keyword(s):  
Avoidance Performance ◽  
Vehicle Speed ◽  
Test Results ◽  
Collision Risk ◽  
Accelerator Pedal ◽  
Internet Of Vehicles ◽  
Emergency Braking ◽  
Intention Recognition ◽  
Braking Distance ◽  
Driver’S Intention

Driver’s intention of the front vehicle plays an important role in the automatic emergency braking (AEB) system. If the front vehicle brakes suddenly, there is potential collision risk for following vehicle. Therefore, we propose a driver’s intention recognition model for the front vehicle, which is based on the backpropagation (BP) neural network and hidden Markov model (HMM). The brake pedal, accelerator pedal, and vehicle speed data are used as the input of the proposed BP-HMM model to recognize the driver’s intention, which includes uniform driving, normal braking, and emergency braking. According to the recognized driver’s intention transmitted by Internet of vehicles, an AEB model for the following vehicle is proposed, which can dynamically change the critical braking distance under different driving conditions to avoid rear-end collision. In order to verify the performance of the proposed models, we conducted driver’s intention recognition and AEB simulation tests in the cosimulation environment of Simulink and PreScan. The simulation test results show that the average recognition accuracy of the proposed BP-HMM model was 98%, which was better than that of the BP and HMM models. In the Car to Car Rear moving (CCRm) and Car to Car Rear braking (CCRb) tests, the minimum relative distance between the following vehicle and the front vehicle was within the range of 1.5 m–2.7 m and 2.63 m–5.28 m, respectively. The proposed AEB model has better collision avoidance performance than the traditional AEB model and can adapt to individual drivers.

scholarly journals A Critcal Study of Driving Performance of Heavy Duty Vehicle Running on Long Downhill Road Using Engine Brake

2014 ◽  
Vol 8 (1) ◽  
pp. 475-479 ◽  
Author(s):  
Xuan Zhao ◽  
Xiaolei Yuan ◽  
Qiang Yu
Keyword(s):  
Temperature Rise ◽  
High Speed ◽  
Driving Performance ◽  
Test Results ◽  
Heavy Duty ◽  
Heavy Duty Vehicle ◽  
Simulation Results ◽  
Heavy Duty Vehicles

For ensuring safety of heavy duty vehicles running on long downhill sections, a model was built for the application of engine brake and service brake combination based on test results. A model of brake temperature rise for heavy duty vehicles running on long downhill sections was also constructed. For different braking modes, gear positions, speed and downhill slopes, brake temperature rising to 250°C was used as the index. Then simulation of brake temperature rise and downhill distance was researched. Simulation results illustrate that the combined braking of low gear and high speed should be adopted for heavy duty vehicles running on long downhill sections.

scholarly journals Driver Evaluation in Heavy Duty Vehicles Based on Acceleration and Braking Behaviors

2020 ◽  
Author(s):  
Mehmet Emin Mumcuoglu ◽  
Gokhan Alcan ◽  
Mustafa Unel ◽  
Onur Cicek ◽  
Mehmet Mutluergil ◽  
...  
Keyword(s):  
Heavy Duty ◽  
Heavy Duty Vehicles

scholarly journals Dual Stage Multilevel Control for Heavy Duty Vehicles under Different Traffic Conditions

2020 ◽  
Vol 53 (2) ◽  
pp. 13850-13854
Author(s):  
P. Polverino ◽  
I. Arsie ◽  
C. Pianese
Keyword(s):  
Heavy Duty ◽  
Traffic Conditions ◽  
Dual Stage ◽  
Heavy Duty Vehicles

scholarly journals Car braking effectiveness after adaptation for drivers with motor dysfunctions

2021 ◽  
Vol 11 (1) ◽  
pp. 617-623
Author(s):  
Adam Sowiński ◽  
Tomasz Szczepański ◽  
Grzegorz Koralewski
Keyword(s):  
Efficiency Index ◽  
Mathematical Function ◽  
Test Results ◽  
Braking Performance ◽  
Braking System ◽  
System Adaptation ◽  
Parametric Description ◽  
Limited Power ◽  
Braking Force ◽  
Selection Of

Abstract This article presents the results of measurements of the braking efficiency of vehicles adapted to be operated by drivers with motor dysfunctions. In such cars, the braking system is extended with an adaptive device that allows braking with the upper limb. This device applies pressure to the original brake in the car. The braking force and thus its efficiency depend on the mechanical ratio in the adapting device. In addition, braking performance depends on the sensitivity of the car’s original braking system and the maximum force that a disabled person can exert on the handbrake lever. Such a person may have limited power in the upper limbs. The force exerted by the driver can also be influenced by the position of the driver’s seat in relation to the handbrake lever. This article describes the research aimed at understanding the influence of the above-mentioned factors on the car braking performance. As a part of the analysis of the test results, a mathematical function was proposed that allows a parametric description of the braking efficiency index on the basis of data on the braking system, adaptation device, driver’s motor limitations, and the position of the driver’s seat. The information presented in this article can be used for the preliminary selection of adaptive devices to the needs of a given driver with a disability and to the vehicle construction.

Design of combined brake system for light weight scooters

2021 ◽  
pp. 095440702110240
Author(s):  
Yuan-Ting Lin ◽  
Chyuan-Yow Tseng ◽  
Jao-Hwa Kuang ◽  
Yeong-Maw Hwang
Keyword(s):  
Ride Comfort ◽  
Brake System ◽  
Force Distribution ◽  
Test Results ◽  
Systematic Method ◽  
Braking Performance ◽  
Evaluation Indexes ◽  
Low Costs ◽  
Braking Force ◽  
Good Agreement

The combined brake system (CBS) is a mechanism that links the front and rear brakes for scooters. For two-wheeled scooters, a CBS with appropriate braking force distribution can reduce the risk of crashing accidents due to insufficient driving proficiency. The design of the braking force distribution for a CBS is challenging to the designer because it has to fulfill many requirements such as braking performance, ride comfort, reliability, and low costs. This paper proposes a systematic method to optimize the parameters of CBS. The evaluation indexes for the design are first discussed. The steps to determine the critical parameter to meet the indexes and a method to predict braking performance are developed. Finally, driving tests are carried out to verify the effectiveness of the proposed method. Experimental results showed that the deceleration of the tested scooter equipped with the designed CBS achieves an average mean fully developed deceleration (MFDD) of 5.246 m/s2, higher than the homologation requirement. Furthermore, the proposed method’s prediction of braking performance is in good agreement with the test results, with errors <1%.

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