Optimization of Braking Strategy for Automatic Emergency Braking System in Vehicle-Pedestrian Accidents

2020 ◽  
Vol 12 (2) ◽  
Author(s):  
Yubin Qian ◽  
Xueyan Yang ◽  
Lingyun Xiao ◽  
Yican Zhu
Keyword(s):  
Emergency Braking ◽  
Braking System ◽  
Pedestrian Accidents

scholarly journals THEORETICAL-EXPERIMENTAL ASSESMENT OF BRAKING SISTEMS FOR INCLINED LIFTS ACCORDING TO EN 81:22-2014.

2016 ◽  
Author(s):  
Enrique Alcalá ◽  
Beatriz Valles Fernandez ◽  
Angel Luis Martin López
Keyword(s):  
Simulation Model ◽  
Relative Displacement ◽  
Dynamical Behaviour ◽  
Emergency Braking ◽  
Braking System ◽  
Calculation Methodology ◽  
Norm Series ◽  
Definition Of ◽  
Optimal Behaviour

The inclined lifts, in case of emergency braking, can experience high longitudinal decelerations that can lead to passengers’ collisions with lift walls and interior elements. In 2014 the CEN/TC10 WG1 published the part 22 of the norm series 81 with regard to the construction elements and installation of electrical lifts with inclined trajectory. This norm stablishes, amongst other requirements, the maximum and minimum deceleration levels in both longitudinal and vertical directions. Both requirements, in opposite senses and the definition of the braking system, do not cause design difficulties in case of high slopes, but in case of lifts with the slope under a certain level they can be needed, to guarantee the fulfilment of the norm, elements that allow and additional relative displacement between the braking system and the cabin. To define the performances and the optimal behaviour of these systems it has been defined a simulation model of the dynamical behaviour of the lift under the conditions of the norm tests. Additionally, in this work it is presented a calculation methodology to define the cabin allowable weight corridor, for each braking effort made by each safety gear model, and the simulations have been validated with the results of tests with different braking efforts, weights and lift slopes. The present work has been performed in cooperation with Thyssen Krupp Elevadores with the aim of improving the knowledge of the brake dynamics of inclined lifts.DOI: http://dx.doi.org/10.4995/CIT2016.2016.2173

scholarly journals Simulation Study of the Process of Friction in the Working Elements of a Car Braking System at Different Degrees of Wear

2018 ◽  
Vol 12 (3) ◽  
pp. 221-226 ◽  
Author(s):  
Andrzej Borawski
Keyword(s):  
Simulation Study ◽  
Friction Pair ◽  
Experimental Studies ◽  
Real Life ◽  
Operating Conditions ◽  
Heating Process ◽  
Passenger Cars ◽  
The Road ◽  
Emergency Braking ◽  
Braking System

Abstract Among the many elements of a modern vehicle, the braking system is definitely among the most important ones. Health, and, frequently, life, may rest upon the design and reliability of brakes. The most common friction pair used in passenger cars today is a disc which rotates with the road wheel and a cooperating pair of brake pads. The composite material of the pad results in changing tribological properties as the pad wears, which was demonstrated in experimental studies. The change is also facilitated by the harsh operating conditions of brakes (high and rapid temperature changes, water, etc.). This paper looks into how changing tribology reflects on the heating process of disc and pads during braking. And so a simulation study was conducted, as this method makes it possible to measure temperature in any given point and at any time, which is either impossible or extremely difficult in real life conditions. Finite element method analyses were performed for emergency braking events at various initial speeds of the vehicle reflecting the current road speed limits.

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 Extremum-seeking algorithms for the emergency braking of heavy goods vehicles

2017 ◽  
Vol 231 (14) ◽  
pp. 1961-1977 ◽  
Author(s):  
Graeme Morrison ◽  
David Cebon
Keyword(s):  
Performance Metrics ◽  
Sliding Mode ◽  
Model Fitting ◽  
Operating Conditions ◽  
Extremum Seeking ◽  
Wheel Slip ◽  
Slip Control ◽  
Emergency Braking ◽  
Braking System ◽  
Heavy Goods Vehicles

A pneumatic slip control braking system was demonstrated, which reduces the emergency stopping distances of heavy goods vehicles by up to 19%. Solutions are still required to set the optimal reference wheel slip for this system online, so that it can adapt to changing operating conditions. This paper considers whether the use of extremum-seeking algorithms is a feasible alternative approach to online tyre model fitting, the computational expense of which has, to date, inhibited real-time implementation. The convergence and the stability properties of a first-order sliding-mode extremum-seeking algorithm are discussed, and its tuneable parameters are recast as physically meaningful performance metrics. Computer simulations are conducted using a detailed braking system model, and hardware-in-the-loop simulations are conducted with prototype pneumatic slip control braking hardware for heavy goods vehicles. The extremum-seeking algorithm enables the braking system to achieve at least 95% of the maximum possible braking force for almost the entirety of an emergency stop. The robustness to parameter errors, the road roughness and the changing friction conditions are all explored.

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