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.

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.

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.

Design, testing and analysis of a novel automotive magnetorheological braking system

2016 ◽  
Vol 231 (10) ◽  
pp. 1402-1413 ◽  
Author(s):  
Liangyao Yu ◽  
Liangxu Ma ◽  
Jian Song
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Reaction Times ◽  
Test Results ◽  
Element Analysis ◽  
Braking Performance ◽  
Braking System ◽  
Magnetic Circuits ◽  
Torque Capacity ◽  
Intensity Magnetic Field

This paper presents a new approach to the design, testing and analysis of a magnetorheological brake which uses a multi-path magnetic circuit to satisfy the braking demand of vehicles. In contrast with a general braking system, an automotive brake exhibits an outstanding performance for high torques and long reaction times. We use a proposed power-law model and finite element analysis to obtain the magnetorheological braking performance for a high shear rate and a high-intensity magnetic field. Finite element analysis with different structures is adopted to determine the parameters of the magnetorheological braking and the layout of the magnetic circuits. An integrated prototype is also fabricated and tested. The test results show that the brake torque is relatively high, and the torque can be accurately controlled by the input current. The reaction time is less than 100 ms. We also analyse the experimental results and use these as the basis for fabricating a full-sized prototype. The full-sized prototype generally exhibits a high torque capacity and a fast dynamic response, thereby validating the feasible application of magnetorheological fluids in automotive braking.

Virtual prototype and field test study on hydraulic brake system performance of mining truck

2018 ◽  
Vol 233 (2) ◽  
pp. 236-253
Author(s):  
Xiaobin Fan ◽  
Jing Gan
Keyword(s):  
Pressure Rise ◽  
Virtual Prototype ◽  
Front Wheel ◽  
Simulation Software ◽  
Dump Truck ◽  
System Response ◽  
Prototype Model ◽  
Braking Performance ◽  
Emergency Braking ◽  
Braking System

In order to study the braking performance of mining dump truck, the modeling of the oil–gas suspension, front and rear brake of the dump truck were carried out first. Then the virtual prototype model of the dump truck was established in multibody dynamic simulation software. The simulation of braking and emergency braking performance, brake deviation on the flat road, and 9% downhill road were carried out. The brake in driving performance, emergency brake performance, disc brake retardance performance, transmission retardance performance, and hydraulic braking system response time were carried out by the real vehicle experiment, respectively. The result shows that the clearance elimination and pressure rise time of braking system are slightly long, especially the clearance elimination time, so the oil system should have an improvement. At the same time, the braking force distribution of the front and the rear is not reasonable, and the front wheel braking torque is slightly insufficient. After solving these problems by authors’ project team, the braking performance of the mine dump truck has been improved significantly.

scholarly journals Holistic Vehicle Instrumentation for Assessing Driver Driving Styles

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1427
Author(s):  
María Garrosa ◽  
Ester Olmeda ◽  
Sergio Fuentes del Toro ◽  
Vicente Díaz
Keyword(s):  
Autonomous Vehicles ◽  
Autonomous Vehicle ◽  
Experimental Tests ◽  
Dynamic Responses ◽  
Emergency Braking ◽  
Braking System ◽  
Hydraulic Brake ◽  
Driving Scenario ◽  
Real Time Information ◽  
Time Information

Nowadays, autonomous vehicles are increasing, and the driving scenario that includes both autonomous and human-driven vehicles is a fact. Knowing the driving styles of drivers in the process of automating vehicles is interest in order to make driving as natural as possible. To this end, this article presents a first approach to the design of a controller for the braking system capable of imitating the different manoeuvres that any driver performs while driving. With this aim, different experimental tests have been carried out with a vehicle instrumented with sensors capable of providing real-time information related to the braking system. The experimental tests consist of reproducing a series of braking manoeuvres at different speeds on a flat floor track following a straight path. The tests distinguish between three types of braking manoeuvre: maintained, progressive and emergency braking, which cover all the driving circumstances in which the braking system may intervene. This article presents an innovative approach to characterise braking types thanks to the methodology of analysing the data obtained by sensors during experimental tests. The characterisation of braking types makes it possible to dynamically classify three driving styles: cautious, normal and aggressive. The proposed classifications allow it possible to identify the driving styles on the basis of the pressure in the hydraulic brake circuit, the force exerted by the driver on the brake pedal, the longitudinal deceleration and the braking power, knowing in all cases the speed of the vehicle. The experiments are limited by the fact that there are no other vehicles, obstacles, etc. in the vehicle’s environment, but in this article the focus is exclusively on characterising a driver with methods that use the vehicle’s dynamic responses measured by on-board sensors. The results of this study can be used to define the driving style of an autonomous vehicle.

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.

A Novel Control Algorithm of Electronic Braking System for Trucks

2013 ◽  
Vol 694-697 ◽  
pp. 2106-2109
Author(s):  
Li Mai ◽  
Li Ya Wang ◽  
Pei Wen Mi ◽  
Sheng Nan Yang
Keyword(s):  
Control Algorithm ◽  
Rear Axle ◽  
Force Distribution ◽  
Vehicle Dynamic ◽  
Braking Performance ◽  
Emergency Braking ◽  
Braking System ◽  
Braking Force ◽  
Brake Wear ◽  
Vehicle Dynamic Model

Electronic Braking System (EBS) can improve the braking performance of trucks significantly. A novel control algorithm for EBS has been proposed in this paper, which consists of Driving Identification Module and Braking Force Distribution Module. Driving Identification Module can recognize the non-emergency braking situation according to the signal of the electronic braking pedal. Braking Force Distribution Module regulates the braking force on front and rear axle by comparing the slip-ratios on every axle. As a result, the optimum braking pressure on different axles can enhance the safety and balance the brake wear. The performance of the control algorithm has been simulated utilizing 15-DOF vehicle dynamic model. The results show that the control algorithm can provide a good braking feeling and the braking performance of the vehicle is perfect.

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%.

Improved AEB algorithm combined with estimating the adhesion coefficient of road ahead and considering the performance of EHB

2021 ◽  
pp. 095440702110261
Author(s):  
Dequan Zeng ◽  
Zhuoping Yu ◽  
Lu Xiong ◽  
Junqiao Zhao ◽  
Peizhi Zhang ◽  
...  
Keyword(s):  
Joint Probability ◽  
Principal Component ◽  
Test Results ◽  
Safe Distance ◽  
Adhesion Coefficient ◽  
The Road ◽  
Response Characteristics ◽  
Emergency Braking ◽  
Multiple Beams ◽  
Maximum Method

This paper proposes an improved autonomous emergency braking (AEB) algorithm intended for intelligent vehicle. Featuring a combination with the estimation of road adhesion coefficient, the proposed approach takes into account the performance of electronic hydraulic brake. In order for the accurate yet fast estimate of road ahead adhesion coefficient, the expectation maximization framework is applied depending on the reflectivity of ground extracted by multiple beams lidar in four major steps, which are the rough extraction of ground points based on 3 σ criterion, the accurate extraction of ground points through principal component analysis (PCA), the main distribution characteristics of ground as extracted using the expectation maximum method (EM) and the estimation of road adhesion coefficient via joint probability. In order to describe the performance of EHB, the response characteristics, as well as the forward and adverse models of both braking pressure and acceleration are obtained. Then, with two typical roads including single homogeneous road and fragment pavement, the safe distance of improved AEB is modeled. To validate the algorithm developed in this paper, various tests have been conducted. According to the test results, the reflectivity of laser point cloud is effective in estimating the road adhesion coefficient. Moreover, considering the performance of EHB system, the improved AEB algorithm is deemed more consistent with the practicalities.

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