Browse Topic: Vehicle deceleration

Items (192)

A Model for the Design of Automated Vehicle Event Data Recorders

2025-01-8678

04/01/2025

When vehicle accidents occur, investigators rely on event data recorders for accident investigations. However current event data recorders do not support accident investigation involving automated or self-driving vehicles when there is state information that needs to be recorded, for example ADS modes, changes in the ODD that the vehicle operates under, and the various states of vehicle features such as intelligent cruise control, automated lane changes, autonomous emergency braking, and others. In this paper, we propose a model to design new types of event data recorders that supports accident investigations involving automated vehicles when there is state information to be recorded. The model is generic enough to be adapted to any automation level and any set of automated vehicle functional features. The model has been instantiated to a specific ADAS system.

Pimentel, Juan

Decelerations for Vehicles with Anti-Lock Brake Systems (ABS) during Wet-to-Dry Transitions on Asphalt and Concrete Road Surfaces

2025-01-8703

04/01/2025

The braking performance of newer anti-lock braking system (ABS) equipped vehicles on roads with varying wetness levels is not well studied. Two late-model ABS-equipped vehicles were used to perform ABS-engaged braking tests on dry and wet asphalt and concrete surfaces from which vehicle speed and deceleration as a function of time were calculated. Tests were initially conducted on a dry surface before a water truck distributed water onto the road to create a wet road condition. A continuous series of tests were then performed until the road dried and the cycle was repeated multiple times. Across all tests of both vehicles on both road surfaces, deceleration levels generally decreased when the road was wet and returned to dry levels only when less than 25% of the road surface remained wet. Also, wet deceleration levels were high compared to the historical values used for wet roads. These findings provide a useful and readily identifiable boundary between what can be considered a dry and

Miller, Ian, King, David, Siegmund, Gunter

Research on Motor Safety Monitoring Control for Powertrain Control System

2025-01-8511

04/01/2025

The motor controller, as one of the important controllers in the electric drive system, may cause unexpected acceleration or deceleration of the vehicle by the driver due to systematic failure and random hardware failure. Conducting research on the functional safety of drive motors for new energy vehicles is of great significance for reducing the systematic failure and random hardware failure of the electric drive. This paper has carried out designs including the allowable motor torque design for safety monitoring, the motor torque prediction design for safety monitoring, the rationality judgment design of the motor torque for safety monitoring, the rationality judgment design of the motor direction for safety monitoring, the functional safety motor degradation design, and the active discharge state monitoring of the motor, so that the system can transition to a safe state when an error occurs. Among them, the motor torque prediction design for safety monitoring includes predicting the

Jing, Junchao, Zuo, Botao, Liu, Yiqiang, Huang, Weishan, Dai, Zhengxing

Research on Torque Management Safety Monitoring Control for Hybrid Vehicles

2025-01-8579

04/01/2025

Hybrid vehicles are driven by the vehicle controller, engine controller and motor controller through torque control, and there may be unexpected acceleration or deceleration of the vehicle beyond the driver's expectation due to systematic failure and random hardware failure. Based on the torque control strategy of hybrid vehicles, the safety monitoring model design of torque control is carried out according to the ISO 26262 safety analysis method. Through the establishment of safety goals and the analysis of safety concepts, this paper conducts designs including the driver allowable torque design for safety monitoring, the driver torque prediction design for safety monitoring, the rationality judgment design of driver torque for safety monitoring, the functional safety degradation design, and the engine start-stop status monitoring, enabling the system to transition to a safe state when errors occur. Firstly, the design of the driver's allowable torque includes the allowable requested

Jing, Junchao, Wang, Ruiguang, Liu, Yiqiang, Huang, Weishan, Dai, Zhengxing

Modeling and Analysis of Comfort Braking Control Based on Brake-by-Wire and Active Suspension Systems

10-09-02-0011

02/07/2025

As wire control systems advance, they have given rise to a diverse suite of advanced driver assistance services and sophisticated fusion control capabilities. This article presents an innovative strategy for achieving comfortable braking in electric vehicles, propelled by the unwavering goal of enhancing driving experience. By integrating active suspension systems with brake-by-wire technology, the approach ensures that drivers retain their confidence throughout the braking process. The brake-by-wire system adeptly discerns the driver’s braking intent through the pedal’s displacement sensor. Utilizing this technology, we have developed a pioneering function aimed at delivering comfort braking control (CBC). This function not only refines the braking experience but also solidifies the driver’s trust in the braking system. Designed to counteract the head nodding effect during vehicle deceleration, the CBC system minimizes or even eradicates the jarring sensation of pitching for both the

Tian, Boshi, Li, Liang, Liao, Yinsheng, Lv, Haijun, Qu, Wenying, Hu, Zhiming, Sun, Yue

Crash Simulation of Steel-Wood Hybrid Road Safety Barrier with Perforated Post Design: TB 11 Evaluation

2024-28-0162

12/05/2024

Research areas in Road furniture have become critical due to the rising incidence of road accidents and fatalities. Enhancing road attributes such as crash barriers, crash cushions, crash poles, and emergency communication systems can significantly reduce these fatalities. Among these, crash barriers promise particular attention as they serve as immediate safety mechanisms. When a vehicle loses control, crash barriers can effectively mitigate the severity of accidents by restraining the vehicle and preventing more severe outcomes. This paper focuses on the performance of a novel steel-wood hybrid crash barrier with perforated post parallel to vehicles direction, designed to enhance road safety in hilly areas. Utilizing finite element analysis (FEA) in LS-DYNA software, renowned for simulating structural deformation under loading, we evaluated the structural response and crashworthiness of the hybrid barrier under various impact scenarios. Our simulations assessed the barrier's

Bendre, Sagar, Das, Alakendu, Jaiswal, Manish

An Economical Multilevel Backup Strategy for Electro-Hydraulic Braking System by Integrating Driving and Electronic Parking Brake Systems

10-08-04-0029

09/24/2024

The braking system stands as a vital component within a vehicle; its malfunction has the potential to precipitate catastrophic or severe accidents. There are two primary backup strategies: one involves hardware redundancy, and the other is the optimization of software strategies in conjunction with other systems. Redundancy among various actuators of the second strategy not only maximizes the vehicle’s inherent capabilities but also results in cost savings. In this article, a multilevel backup strategy that integrates electro-hydraulic braking, driving systems, and electronic parking brake systems is explored. Utilizing a self-developed braking safety control system, a proposal is made for the electronic parking brake to participate in service braking. Additionally, two functional modules, pre-clamping and deceleration following, have been meticulously designed to tackle the challenges of response delay and insufficient control precision that are commonly associated with electronic

Tian, Boshi, Li, Liang, Liao, Yinsheng, Lv, Haijun, Wang, Xiangyu, Hu, Zhiming, Sun, Yue, Qu, Wenying

Virtual Brake Pull Maneuver Development

2023-36-0021

01/08/2024

The Brake Pull phenomena is the directional deviation when a strong deceleration is applied, this happens due to asymmetries in the vehicle with diverse origins: dimensional, stiffness, damping, friction and loading condition. This phenomenon creates the necessity of driver inputs on the steering wheel adjusting the vehicle direction to keep the straight line. Great part of asymmetries in the vehicle is avoidable due to building quality, correct maintenance, and others. However, an unequal loading condition on the transversal direction of the vehicle is very common: the vehicle occupied only by the driver is a usual condition. This circumstance creates a load asymmetry that can induces the brake pull phenomena. This study aims to create and validate a virtual toll capable of representing the brake pull phenomena caused by a loading asymmetry. A vehicle modeled in multibody dynamics technique representing the vehicle mass inertias, suspension mechanisms kinematics, tire behavior and

Terra, Rafael Tedim

Optimization of Brake System Parameters Using Genetic Algorithm

2023-01-1881

11/05/2023

The design of brake system specification is an iterative process, where repeated calculations need to be performed to achieve the target brake performance and finalize the system parameters. Hence there is a need for a methodology to arrive at a set of optimized brake system parameters which can in turn reduce the brake system definition time. In this paper, the brake system dynamics of a passenger/commercial vehicle is mathematically modelled (divided into two parts i) foundation brake model ii) brake apply system model) and uses genetic algorithm to optimize the system parameters. The objective function maximizes the vehicle deceleration and arrives at the target brake feel which includes brake pedal effort and brake pedal travel. When compared to conventional method of brake design which uses iterative approach, this method has the capability to arrive at the optimized results at a faster rate.

Velumani, Sivaramakrishnan, Balasubramani, Arunchandran

The Impact of Seat Belt Pretensioner Deployment on Forward-Leaning Occupants

09-11-02-0019

09/20/2023

Pyrotechnic seat belt pretensioners typically remove 8–15 cm of belt slack and help couple an occupant to the seat. Our study investigated pretensioner deployment on forward-leaning, live volunteers. The forward-leaning position was chosen because research indicates that passengers frequently depart from a standard sitting position. Characteristics of the 3D kinematics of forward-leaning volunteers following pretensioner deployment determines if body size is correlated with subject response. Nine adult subjects (three female), ages 18–43 years old, across a wide range of body sizes (50–120 kg) were tested. The age was limited to young, active adults as pyrotechnic pretensioners can deliver a notable force to the trunk. Subjects assumed a forward-leaning position, with 26 cm between C7 and the headrest, in a laboratory setting that replicated the passenger seat of a vehicle. At an unexpected time, the pretensioner was deployed. 3D kinematics were measured through a nine-camera motion

Hellenbrand, Ciboney, Brown, J. Fletcher, Goodworth, Adam

Post-Collision Run-Out Vehicle Deceleration Based on Real-World Data

2023-01-5063

09/13/2023

In traffic accidents, the run-out is the phase after impact until reaching a final rest position. Analyzing and reconstructing this phase is a task leading sometimes to a broad bandwidth of results. This can be due to the unknown driver’s reaction and braking behavior. The well-known literature describes rollout decelerations, but these exclude the influence of the driver, particularly with regard to accident situations. Measurement data from real-world collisions can help quantifying the vehicle’s deceleration during the run-out and thus at least partially close the existing research gap. Therefore, this study deals with the systematic evaluation of real-world measurement data from intersection collisions collected by accident data recorders. The high-frequency acceleration and speed data of 45 accident vehicles with impact velocities up to 70 kph were processed for this purpose; characteristic values for the run-out phase were calculated in each case and then statistically evaluated

Fuerbeth, Uwe

A Modified Enhanced Driver Model for Heavy-Duty Vehicles with Safe Deceleration

2023-24-0171

08/28/2023

To accurately evaluate the energy consumption benefits provided by connected and automated vehicles (CAV), it is necessary to establish a reasonable baseline virtual driver, against which the improvements are quantified before field testing. Virtual driver models have been developed that mimic the real-world driver, predicting a longitudinal vehicle speed profile based on the route information and the presence of a lead vehicle. The Intelligent Driver Model (IDM) is a well-known virtual driver model which is also used in the microscopic traffic simulator, SUMO. The Enhanced Driver Model (EDM) has emerged as a notable improvement of the IDM. The EDM has been shown to accurately forecast the driver response of a passenger vehicle to urban and highway driving conditions, including the special case of approaching a signalized intersection with varying signal phases and timing. However, most of the efforts in the literature to calibrate driver models have focused on passenger vehicles. This

Shiledar, Ankur, Villani, Manfredi, Rizzoni, Giorgio, Adinolfi, Ennio Andrea, Pandolfi, Alfonso, Paolino, Antonio, Pianese, Cesare

Model-Free Intelligent Control for Antilock Braking Systems on Rough Roads

10-07-03-0017

05/26/2023

Advances made in advanced driver assistance systems such as antilock braking systems (ABS) have significantly improved the safety of road vehicles. ABS enhances the braking and steerability of a vehicle under severe braking conditions. However, ABS performance degrades on rough roads. This is largely due to noisy measurements, the type of ABS control algorithm used, and the excitation of complex dynamics such as higher-order tire mode shapes that are neglected in the control strategy. This study proposes a model-free intelligent control technique with no modelling constraints that can overcome these unmodelled dynamics and parametric uncertainties. The double deep Q-learning network (DDQN) algorithm with the temporal convolutional network is presented as the intelligent control algorithm. The model is initially trained with a simplified single-wheel model. The initial training data are transferred to and then enhanced using a validated full-vehicle model including a physics-based tire

Abreu, Ricardo, Botha, Theunis R., Hamersma, Herman A.

Decelerations for Vehicles with Anti-lock Brake Systems (ABS) on Dry Asphalt and Concrete Road Surfaces

2023-01-0616

04/11/2023

Anti-lock brake systems (ABS) produce high levels of vehicle deceleration under emergency braking conditions by modulating tire slip. Currently there are limited data available to quantify the mean, variance, and distribution of vehicle deceleration levels for modern ABS-equipped vehicles. We conducted braking tests using twenty (20) late-model vehicles on contiguous dry asphalt and concrete road surfaces. All vehicles were equipped with a 5th wheel sampled at 200 Hz, from which vehicle speed and deceleration as a function of time were calculated. Eighteen (18) tests were conducted for each vehicle and all tests were conducted from a targeted initial speed of 65 km/h (40 mph). Overall, we found that late-model ABS-equipped vehicles can decelerate at average levels that vary from about 0.871g to 1.081g across both surfaces, and that deceleration levels were on average about 0.042g higher on asphalt than on concrete. We also found that the passenger cars decelerated about 0.087g higher

Miller, Ian, King, David, Wilkinson, Craig, Siegmund, Gunter P.

Energy Modeling of Deceleration Strategies for Electric Vehicles

2023-01-0347

04/11/2023

Rapid adoption of battery electric vehicles means improving the energy consumption and energy efficiency of these new vehicles is a top priority. One method of accomplishing this is regenerative braking, which converts kinetic energy to electrical energy stored in the battery pack while the vehicle is decelerating. Coasting is an alternative strategy that minimizes energy consumption by decelerating the vehicle using only road load. A battery electric vehicle model is refined to assess regenerative braking, coasting, and other deceleration strategies. A road load model based on public test data calculates tractive effort requirements based on speed and acceleration. Bidirectional Willans lines are the basis of a powertrain model simulating battery energy consumption. Vehicle tractive and powertrain power are modeled backward from prescribed linear velocity curves, and the coasting trajectory is forward modeled given zero tractive power. Decel modes based on zero battery and motor power

Hom, William, Nelson, Douglas

Quantifying the Deceleration of Various Electric Vehicles Utilizing Regenerative Braking

2023-01-0623

04/11/2023

Regenerative braking is present in almost all electric vehicle models and as the demand for electric vehicles grows, the types of electric vehicles grow as well. Regenerative braking allows for an electric vehicle to convert a vehicle's kinetic energy into electrical potential energy by utilizing the electric motors to slow the vehicle. This potential energy is then returned to the vehicle’s battery allowing for the vehicle’s range to be extended. The vehicles tested during the study were as follows: 2022 Rivian R1T, 2022 Tesla Model Y, 2022 Hyundai Ioniq 5, 2020 Tesla Model 3, 2021 Volkswagen ID.4, and 2021 Ford Mustang Mach-E. Although regenerative braking slows the vehicle, not all levels of regenerative braking bring the vehicle to a complete stop. The study showed that there are typically two types of regenerative braking. The first, commonly referred to as one-pedal driving, will bring a vehicle to a complete stop without the application of the brake pedal. The other slows the

Vigil, Cole Mackenzie, Kaayal, Omar, Szepelak, Alexander

Development of Truck Platooning System Including Emergency Braking Function with Vehicle-in-the-Loop (VIL) Testing

2023-01-0571

04/11/2023

Platoon is a system that connects vehicles through vehicle-to-vehicle (V2V) communication technology to maintain a short distance between vehicles while driving on the road. To improve fuel efficiency, many automotive original equipment manufacturers (OEMs) are interested in developing and demonstrating real-world platoon system. However, it is hard for heavy duty trucks to develop this system due to the difficulty of maintaining the targeted intervehicle distance not only for fuel efficiency but also for safety in case of emergency braking. Because of this critical safety issue in the emergency situation, the platoon system for heavy duty trucks can be hardly demonstrated or tested in real vehicle environment. The relatively complex system and the slow response characteristic of commercial vehicles makes this even more difficult. In this paper, focusing on the emergency braking function implemented through the V2V communication interface, we introduce the platoon system developed by

Hong, Jeong-Ki, Kim, Sangjun, Lim, Jong Su, Nam, Joohan, Min, Byeonghyeok, Lee, Chanhwa

Evaluation of Occupant Kinematics and Kinetics during Moderate Severity Simulated Frontal Impacts with and without Frontal Airbag Deployment

2023-01-0559

04/11/2023

Airbag and seat belt pretensioner deployment characteristics depend on multiple factors, such as the magnitude, direction, and rate of vehicle deceleration as detected by vehicle crash sensors and evaluated by vehicle-specific algorithms. Frontal airbag and pretensioner deployments are likely to be commanded during frontal crash events with high initial vehicle deceleration typically associated with high vehicle change in velocity (delta-V). However, within a range of moderate changes in vehicle speeds, referred to as the “gray zone,” a vehicle-specific algorithm may or may not command deployment depending on crash pulse parameters and occupant sensing, among other items. Publicly available testing in the moderate-speed range is lacking and would be useful to evaluate the effects of airbag and pretensioner deployment on occupant kinematics and loading. In this study, sled tests were performed using a standard passenger vehicle buck simulating frontal deceleration impact events in a

Sharpe, Sarah S., Grijalva, Sandra, Allin, Leigh, Courtney, Amy, Toney-Bolger, Megan, Pokutta-Paskaleva, Anastassia, Crosby, Charles L., Carhart, Michael

Electric Motorcycle Acceleration, Braking, and Regenerative Coast-Down Deceleration Testing and Analysis

2023-01-0631

04/11/2023

Three fully electric motorcycles were tested and analyzed for acceleration, braking, and regenerative coast-down deceleration. A Zero DSR, BMW C-Evolution, and a Harley-Davidson LiveWire underwent each of the following test series. The first test series consisted of accelerating the electric motorcycles from a stop. For the second test series, the motorcycles were decelerated by using three different brake applications: front and rear brake application, front-only brake application, and rear-only brake application. For the third test series, regenerative coast-down deceleration was tested at different ride mode configurations. Regenerative braking systems are designed to convert the vehicles’ kinetic energy into electrical potential energy during the vehicles’ coast-down phase, resulting in a moderate deceleration. In addition to testing the vehicles’ deceleration during its’ regenerative coast-down phase, brake light activation delay relative to throttle roll-off was analyzed. All

Phan, Chris, Meza Buendia, Saul A., Nguyen, Benjamin Mai, Fatzinger, Edward, Landerville, Jon

Forward Collision Warning and Automatic Emergency Braking Test Procedure and Minimum Performance Requirements - Truck and Bus

J3029_202301 (Current)

01/17/2023

This SAE Recommended Practice (RP) establishes uniform powered vehicle-level test procedure for forward collision warning (FCW) and automatic emergency braking (AEB) used in trucks and buses greater than 10000 pounds (4535 kg) GVWR equipped with pneumatic brake systems for detecting, warning, and avoiding potential collisions. This RP does not apply to electric powered vehicles, trailers, dollies, etc., and does not intend to exclude any particular system or sensor technology. These FCW/AEB systems utilize various methodologies to identify, track, and communicate data/information to the operator and vehicle systems to warn, intervene, and/or mitigate in the momentary longitudinal control of the vehicle. This specification will test the functionality of the FCW/AEB (e.g., ability to detect objects in front of the vehicle), its ability to indicate FCW/AEB engagement and disengagement, the ability of the FCW/AEB to notify the human machine interface (HMI) or vehicle control system that an

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Braking Dynamics of Auto-Rickshaw

2022-28-0382

10/05/2022

Auto-rickshaw is one of the most customary modes of transport in urban as well as rural areas of India. The safety of this vehicle is of prime concern. The braking system plays a vital role in the safety of any vehicle. This work is carried out in order to analyze the vehicle behavior during braking maneuver since the literature survey carried out had fewer details about the braking performance of Auto-rickshaw. Bajaj RE was chosen in particular for our study because it is widely used. Stopping distance analysis is utilized in order to estimate the vehicle braking performance. The straight-line braking performance is studied with the help of a 3-DOF mathematical model of the vehicle developed which includes the surge, heave and pitch motions. This model is formulated based on the Newtonian approach and is built on Simulink environment. The complete brake system is developed and coupled with the mathematical model. The Pacejka tire model is implemented in order to obtain accurate

M H, Akshith, Anand, Srijan, Chakravarthy, Raghav, N H, Hemanth, Patil, Sharanbasappa

Estimation Parameters of Braking of Vehicles Category M1 at Definition of Circumstances Road Accidents

2022-01-1166

09/19/2022

The study of the distribution of the deceleration of vehicles of category M1 when performing various maneuvers is intended to develop methods for assessing the parameters of maneuvering of cars in the study of the circumstances of the occurrence of road accidents. Experimental studies were carried out on passenger cars, which are equipped with automated braking force control systems, for various driving styles. M1 category vehicles were maneuvered on dry asphalt pavement in the range of speeds from 11 to 25 m / s, which is typical for most road traffic accidents. It was found that when braking a vehicle of category M1, longitudinal deceleration increase according to a second-order polynomial dependence in the range of deceleration variation from 1.39 to 5.86 m/s2. This fact is well explained by the peculiarities of the operation of automated brake force control systems that are equipped a vehicle and the psychological behavior of the driver, who carries out the process of braking the

Kashkanov, Andrii, Kashkanova, Anastasiia, Podrigalo, Mikhail, Klets, Dmytro, Saraiev, Oleksii, Mikhalevich, Mykola, Andrey, Korobko

Decelerations of Capsized Motorcycles - An Update

2022-01-0823

03/29/2022

Many motorcycle crashes involve the motorcycle capsizing, impacting the ground, and sliding on the road surface. When performing speed calculations, the energy or speed loss for the ground impact and sliding phases may need to be calculated. To perform these calculations, the reconstructionist will typically determine the slide distance based on the physical evidence and then apply a range of decelerations over that distance based on test data in the literature. Decelerations can be selected for motorcycles with similar characteristics (crash bars, panniers, fairings, etc.) sliding on similar surfaces (asphalt, concrete, dirt, gravel, etc.). This approach is adequate but sometimes results in a wide range due to the variability in reported decelerations in prior studies. It could be helpful to narrow the likely range of decelerations, and thus, the speed range. Many past studies, however, describe their tests with inadequate detail to parse out precisely what factors were most

Rose, Nathan, Palmer, Jacob, Smith, Connor, Carter, Neal, Walter, Kevin

New Metrics for Quantifying the Energy Efficiency of Platoons in the Presence of Disturbances

2022-01-0526

03/29/2022

Due to aerodynamic drag reduction, vehicles may have significant energy savings while platooning in close succession. However, when circumstances force active deceleration to maintain the platoon, such as during vehicle cut-ins or grade changes, the aerodynamic efficiency benefits may be undermined by losses in kinetic energy. In this work, a theoretical relationship is derived to correlate the amount of active deceleration a vehicle experiences with energy efficiency. The derived relationship is leveraged to analyze platooning data from the last vehicle in a class 8 vehicle platoon. The data include both two- and four-truck platoons operating under nine different truck-to-truck gap control strategies. Using J1939 CAN data and GPS-estimated grade profiles, off-throttle data were isolated and longitudinal acceleration is estimated as a function of grade using Kalman filtering. Using bounding regions to isolate coasting data from active deceleration data, the active deceleration losses

Stegner, Evan, Snitzer, Philip, Bevly, David, Hoffman, Mark

Research on Hierarchical Control of Automobile Automatic Emergency Braking System Based on V2V

2021-01-7025

12/15/2021

In order to ensure braking efficiency and improve the comfort of drivers and passengers, a two-stage braking grading control system was proposed. In the upper controller, the enhanced time-to-collision model under different working conditions was designed, and the braking threshold was determined considering the comfort of braking drivers and passengers, and the driver’s braking behavior was analyzed to determine the vehicle braking deceleration. The vehicle longitudinal dynamic model was built in the lower layer, the PID controller was used to reduce the model deviation. This paper improves the test standard on the basis of China-New Car Assessment Program. The results show that the remaining relative distance between the two vehicles was in the safe range. The control strategy can achieve collision avoidance of vehicle emergency braking.

ZHANG, Senlin, OU, Jian, DENG, Guohong, XU, Ze

Research on Trajectory Planning and Tracking Strategy of Lane-changing and Overtaking based on PI-MPC Dual Controllers

2021-01-1262

10/11/2021

Aiming at the problem of poor robustness after the combination of lateral kinematics control and lateral dynamics control when an autonomous vehicle decelerates and changes lanes to overtake at a certain distance. This paper proposes a trajectory determination and tracking control method based on a PI-MPC dual algorithm controller. To describe the longitudinal deceleration that satisfies the lateral acceleration limit during a certain distance of lane change, firstly, a fifth-order polynomial and a uniform deceleration motion formula are established to express the lateral and longitudinal displacements, and a model prediction controller (MPC) is used to output the front wheel rotation angle. Through the dynamic formula and the speed proportional-integral (PI) controller to control and adjust the brake pressure. Based on simulation to optimize the best lane change completion time coefficient at different longitudinal lane change speeds, the relationship between the vehicle collision

Yin, Jian, Chen, Xu Jia, Zu, Bingfeng, Xu, Yuliang, Zhou, Jianwei

Detailed Modeling of Pneumatic Braking in Long Combination Vehicles

02-14-03-002008/23/2021

A detailed model for pneumatic S-cam drum brake systems is developed and integrated into a multibody dynamic model for a 33-ft A-double long combination vehicle (LCV). The model, developed in TruckSim®, is used to study the dynamics of LCVs during straight-line braking at various speeds. It includes the response delay in braking that occurs from the time of application to when the brakes are applied at the drum for all axles. Additionally, the model incorporates an accurate characterization of brake torque versus chamber pressure at different speeds, along with the anti-lock brake system (ABS) dynamics, to yield an accurate prediction of the vehicle’s deceleration during braking. The modeling results are compared with test results at speeds ranging from 20 mph to 65 mph on dry pavement. A close match between the model’s prediction and test results is observed. The model is then used to perform a parametric study that evaluates braking distance and time for different pavement

Zhang, Zichen, Sun, Nan, Chen, Yang, Ahmadian, Mehdi

Intelligent Deceleration Energy-Saving Control Strategy for Electric Vehicle

2021-01-0123

04/06/2021

In order to improve the vehicle economy of electric vehicles, this paper first analyzes the energy-saving mechanism of electric vehicles. Taking the energy consumption of the deceleration process as a starting point, this paper deeply analyzes the energy consumption of the deceleration process under several different control modes by the test data, so as to obtain two principles that should be followed in energy-saving control strategy. Then, an intelligent deceleration energy-saving control strategy by getting the forward vehicle information is developed. The overall architecture of the control strategy consists of three parts: information processing, target calculation and torque control. The first part is mainly to obtain the forward vehicle information from the perception systems, and the user's habits information from big data, and this information is processed for the next part. The second part mainly determines the entry and exit timing of the intelligent deceleration energy

Zhao, Yongqiang, Zhang, Qiang, Pang, Erchao, Li, Jun, Jiankang, Liu

Performance of the Ford Pre-Collision Assist with Automatic Emergency Braking System in Instrumented Tests

2021-01-0894

04/06/2021

Modern Ford vehicles can be manufactured with a system known as Pre-Collision Assist with Automatic Emergency Braking (AEB). The Pre-Collision Assist feature uses camera technology to detect a potential collision with a vehicle or pedestrian directly ahead. If a potential collision is detected, an alert sound is emitted, and a warning message displays in the vehicle’s message center. If the driver response is not sufficient, AEB will be pre-charged and brake-assist sensitivity will be increased to provide full responsiveness if the driver does brake. If there is no perceived corrective action and a collision is imminent, the vehicle’s brakes can apply automatically. By detecting the possible collision and actuating the braking system, it is possible to prevent some collisions and lessen the severity of others. Testing of this system was conducted using a 2020 Ford Explorer. During several tests, the instrumented Ford was driven at a simulated target vehicle or pedestrian dummy. Data

Vandiver, Wesley, Anderson, Robert

Objectified Drivability Analysis and Evaluation of Deceleration Maneuvers for Electric Vehicles

03-14-03-002302/15/2021

Objectified analysis and evaluation tools offer cost- as well as time-saving potentials regarding the calibration process of vehicle control units. To reduce the time required for the calibration effort, standardized processes including the frontloading of development tasks enable swift calibration procedures and can be used to develop a basis for the comparison of different vehicles and also the calibration quality. In this environment, objectified evaluation methods are also being developed for the investigation of the drivability of electric vehicles. This article presents a methodology for assessing the longitudinal drive behavior of battery electric vehicles during deceleration maneuvers. The aim is to objectively evaluate the vehicle deceleration by means of reproducible driving maneuvers. In addition to further measurement signals, the longitudinal acceleration signal serves as the main evaluation basis. Based on characteristic points during the event, the deceleration maneuver

Ossendorff, Dominik, Heusch, Christian, Tatas, Lauritz, Wick, Maximilian Kurt, Birmes, Georg

Management and Control of Connected and Automated Vehicle Platoon in the Process of Variable Speed Driving, Vehicle Cut-Out or Cut-In

2020-01-5220

12/30/2020

The Connected and Automated Vehicle (CAV) platoon can run at the speed limit and the minimum safe time gap, that is, each vehicle speed is the speed limit and the time gap between adjacent vehicles is the minimum safe time gap known as constant time gap (CTG) strategy, and the platoon will reach the high traffic efficiency. This paper aims at the three situations of variable speed driving, vehicle cut-out and cut-in of the CAV platoon, proposes the methods of CAVs management and control to ensure the efficiency and stability of the CAV platoon in the process of driving using a small number of adjusting parameters. The communication delays among vehicles are considered, the simulation experiments show that the impact of the communication delay (50-200 ms) during acceleration or deceleration is very small, and then this paper adopts the communication delay of 100 ms. The control methods take the minimum safe time gap as the goal, by controlling the acceleration or deceleration of each

Wang, Fujian, Dai, Hongliang, Lu, Yixiao, Han, Haihang

A New Approach of Antiskid Braking System (ABS) via Disk Pad Position Control (PPC) Method

02-14-01-000410/15/2020

A classical antiskid brake system (ABS) is typically used to control the brake fluid pressure by creating repeated cycles of decreasing and increasing brake force to avoid wheel locking, causing the fluctuation of the brake hydraulic pressure and resulting in vibration during wheel rotation. This article proposes a new approach of skid control for ABS by controlling the disk pad position. This new approach involves using a modest control method to determine the optimal skid that allows the wheel to exert maximum friction force for decelerating the vehicle by shifting the brake pad position instead of modulating the brake fluid pressure. This pad position control (PPC) method works in a continuous manner. Therefore, no rapid changes are required in the brake pressure and wheel rotation speed. To identify the PPC braking performance, braking test simulations and experiments have been carried out. The optimal pad position was calculated by estimating the friction coefficient, in which the

Ismail, Hasan, Chieng, Wei-Hua, Jeng, Shyr-Long

Simulation of the Combined Braking Control System for Hybrid Electric Vehicles

2020-01-021704/14/2020

Simulation model of the combined braking control system for hybrid electric vehicles is proposed. The model shows working processes of the braking system with actuating friction mechanisms and an electro-hydraulic drive and regenerative braking system with an electrodynamic mechanism. The electrodynamic mechanism of regenerative braking is formed by switching the traction motor to the generator operating mode. At the same time braking effect is transmitted through the transmission to the drive wheels. The combined control of two brake systems of an electric vehicle is carried out by the driver when acting on one common control element - the brake pedal. Pushing on the braking pedal, driver generates the given control signal- desirable level of electric vehicle deceleration. In accordance with the given control signal, the law of control can be selected in the simulation model - the control function (electric vehicle deceleration) is proportional to the pedal effort or the control

Shuklynov, Serhii, Kholodov, Mykhailo, Verbitskiy, Victor, Makarov, Volodymyr, Ryzhykh, Leonid

Energy-Optimal Deceleration Planning System for Regenerative Braking of Electrified Vehicles with Connectivity and Automation

2020-01-0582

04/14/2020

This paper presents an energy-optimal deceleration planning system (EDPS) to maximize regenerative energy for electrified vehicles on deceleration events perceived by map and navigation information, machine vision and connected communication. The optimization range for EDPS is restricted within an upcoming deceleration event rather than the entire routes while in real time considering preceding vehicles. A practical force balance relationship based on an electrified powertrain is explicitly utilized for building a cost function of the associated optimal control problem. The optimal inputs are parameterized on each computation node from a set of available deceleration profiles resulting from a deceleration time model which are configured by real-world test drivings. Also, to maximize energy recuperation and avoid front collision and jittering, the proposed EDPS uses a hierarchical control architecture with two layers: long-sighted planning system considering the entire scope of

Kim, Dohee, Eo, Jeong Soo, Kim, Yeojun, Guanetti, Jacopo, Miller, Ryan, Borrelli, Francesco

Coasting Technology for Real-World Fuel Economy Improvement of a Hybrid Vehicle

2020-01-1195

04/14/2020

Automobile manufactures need to adopt new technologies to meet global CO2 (carbon dioxide) emission regulations and better fuel efficiency demands from customers. Also, the production cost should be as low as possible for an affordable vehicle. Therefore, it is advantageous for OEMs to develop fuel efficient technologies which can be controlled by software without additional hardware costs. The coasting control is a fuel efficiency improvement technology that can be implemented by the change of vehicle software only. The coasting control is a technology that reduces the driving resistance (Deceleration) when the driver releases the gas pedal. This technology leads to reducing the energy required for the vehicle to drive and results in improving the real-world fuel economy. In an internal combustion engine (ICE) vehicle, the coasting state is achieved by changing the gear to neutral, and the effect has been discussed and clarified by many previous studies. On the other hand, in the

Yamaguchi, Tomoya

Study on Vehicle Spin Tendency during Braking on Differential mu Surfaces in Four Wheeled Automobile Vehicle

2019-01-211409/15/2019

A four-wheeled automobile during braking event in which left and right wheels of the vehicle are on different mu surfaces, has high chances of experiencing spin, which may lead to stability issues on vehicle. This paper intends to provide a mathematical approach to predict the deceleration at which vehicle will spin during braking in a differential mu surface, and determine the effect of influencing parameters on the extent of the vehicle spin tendency. This paper also provides a correlation between theoretical vs actual decelerations for vehicles to exhibit vehicle spin tendency. This paper helps in providing sufficient aid/tool for system designer to predetermine the vehicle spin at early level of system designs and make necessary amendments at initial stage of prototype development rather than late changes, to create a product which gives safe driving experience.

Nedunuri, Kartheek, K, Rajakumar, Lalasure, Santosh

A Mathematical Model of the Braking Dynamics of a Car

2018-01-189310/05/2018

The braking efficiency of a vehicle is its most important operational property. However, in practice, researchers utilize simplistic physical-mathematical models for the process of vehicle braking that leads to accuracy reduction of these models predictions. The literature data show that the error in assessing braking efficiency can reach 30%. One of the main indicators of the efficiency of a braking system is deceleration. Most accurately, this value can be determined by experimental measurements. However, this is not always possible due to various technical reasons. The existing models typically ignore the impact of the car design and its speed on deceleration. They also either neglect air resistance completely or account only for its horizontal component. This paper presents an improved mathematical model written in the differential form that takes into account the impact of the lifting or downforce components of the aerodynamic forces. The proposed model accounts for the dependence

Saraiev, Olexii, Gorb, Yuliya

Increase of Stability for Motor Cars in Service Braking

2018-01-188010/05/2018

New solutions for actual problems of determination the efficient distribution of braking forces between the axles of the vehicle, and the stability and drivability of two-axles vehicles at service braking are received in the thesis. It permitted for the first time to determine the Law of distribution of the braking forces between the axles, that ensuring straight-running stability of two-axle vehicle at service braking, to obtain the ideal characteristics for the braking system of two-axle vehicle at service braking and to determine possible values for the distribution of braking force on the front axle. The drivability criterion at service braking obtained further development; it is offered to use boundary at gripping front or rear wheels angular vehicle acceleration on the road. The application of the stability coefficient as one of the criteria for service braking efficiency allowed to determine the ideal, as for preserving the road-holding ability, Law of distribution of the

Podrigalo, Mikhail, Turenko, Anatoliy, Bogomolov, Viktor, Klets, Dmytro, Sergiyenko, Oleg, Karpenko, Volodymyr, Gritsuk, Igor V., Turenko, Oleksandr, Korobko, Andrii, Bulgakov, Nickolay, Boboshko, Oleksandr

Maximizing Coasting of 48 V Vehicles with Cold-Storage Evaporator

2018-37-002305/30/2018

One of the main features of 48 V vehicles is the ability to coast at high speeds with the Internal Combustion Engine (ICE) off. This can be realized due to the high torque and power the 48 V motor-generator provides which allows a quick and smooth re-cranking of the ICE. The coasting feature reduces the fuel consumption depending on frequency and duration of the coasting events. This depends in turn on driving pattern, driving style, State-of-Charge of the 48 V and 12 V batteries and the air-conditioning (A/C) system. In summer, if the A/C runs with a mechanical belt-driven compressor, the cabin inlet air temperature from the evaporator inevitably increases during each coasting event as the ICE turns off and cannot operate the compressor. If the evaporator temperature reaches a certain threshold at which the cabin comfort is noticeably affected, the ICE is re-cranked for resuming air-conditioning. This operation during vehicle deceleration and vehicle standstill is inefficient as fuel

Özbek, Markus, Nishida, Shin, Biglia, Matteo, Kohli, Vipul, Inaba, Atsushi, Györög, Tibor, Nishikawa PhD, Michio

Investigating Steady-State Road Load Determination Methods for Electrified Vehicles and Coordinated Driving (Platooning)

2018-01-0649

04/03/2018

Reductions in vehicle drive losses are as important to improving fuel economy as increases in powertrain efficiencies. In order to measure vehicle fuel economy, chassis dynamometer testing relies on accurate road load determinations. Road load is currently determined (with some exceptions) using established test track coastdown testing procedures. Because new vehicle technologies and usage cases challenge the accuracy and applicability of these procedures, on-road experiments were conducted using axle torque sensors to address the suitability of the test procedures in determining vehicle road loads in specific cases. Whereas coastdown testing can use vehicle deceleration to determine load, steady-state testing can offer advantages in validating road load coefficients for vehicles with no mechanical neutral gear (such as plug-in hybrid and electric vehicles). Steady-state testing may also be the only way to directly evaluate vehicle loads during coordinated driving (platooning or

Duoba, Michael, Jehlik, Forrest

Iterative Analysis of Free Acceleration on a Ramp and Free Deceleration (Coast-Down) on a Flat Road for Evaluating Longitudinal Dynamics Parameters of Vehicles

2017-36-0131

11/07/2017

Aiming to find the rotational inertias, the rolling resistance coefficient and the drag coefficient of an electric vehicle, a set of tests was developed based on the speed over time curves in two conditions: free acceleration on a ramp and free deceleration (coast-down) on a flat road. Since the main interest was in knowing the parameters and not only finding the resistance power for different speeds, as is usually the case for a coast-down test, an iterative analysis of both data sets was made. The methodology was validated by testing and analyzing road vehicles, because the values of the parameters were readily available, and by confronting the results of simulations for both types of tests. For the electric vehicle, redundancies and variations were used during testing for validation. The results for the road vehicles were within a margin of up to 10.4% from the reference values.

Carioni, Leonardo Porto, Hoeltgebaum, Thiago, Chierighini, Thiago

Coast Down Curve Computational Modeling and Its Influence on Urban and Highway Autonomy Results

2017-36-0319

11/07/2017

Currently, fuels development is strongly dependent on experiments. New engines and vehicles simulation methodologies contribute to speed up R & D projects deadlines, as well as reducing costs. This paper presents a modeling methodology for a vehicle deceleration load curve (coast down) prediction and simulations of coast down variations impact on urban and highway autonomies. Two coast down curve mathematical models were successfully developed and validated. The first one, based on vehicles technical specifications and empirical equations, resulted in percent differences up to 9% compared to the experimental results. This is lower than the variation established on coast down standard, which is 15%. The second, generated by regression analysis between other vehicles characteristics versus experimental results of F0 and F2 (coast down curve parameters), resulted in percent differences up to 15%, for six of the eight vehicles. A simulator of urban and highway autonomies as coast down load

Villela, Antonio Carlos Scardini, de Carvalho, Rogério Nascimento

An Investigation into C-NCAP AEB System Assessment Protocol

2017-01-2009

09/23/2017

In order to speed up the development of vehicle active safety technology in China, C-NCAP plans to add AEB and AEB VRU system as assessment items in 2018. With the purpose of studying the assessment protocol of AEB system, we have carried out 400,000 km road information collection and then we acquired the statistics of the operation conditions of dangerous situations. Combined with the traffic accident data collected by CIDAS, we found that the dangerous situations that we usually met were mainly three types, that was CCRs, CCRm and CCRb. Based on what we mentioned above, we analyzed the three kinds of working conditions and gave the corresponding evaluation method. In addition, combined with the actual situation of China, we added two tests of error function. And then we took the actual road experiment of many models of vehicles. We made a count on twenty vehicles which were domestic sold from joint ventures and autonomous vehicles with the purpose of analyzing the deceleration of

Guo, Kuiyuan, Yan, Yan, Shi, Juan, Guo, Runqing, Liu, Yuguang

Potential Effects of Deceleration Pulse Variations on Injury Measures Computed in Aircraft Seat HIC Analysis Testing

2017-01-2052

09/19/2017

Aircraft seating systems are evaluated utilizing a variety of impact conditions and selected injury measures. Injury measures like the Head Injury Criterion (HIC) are evaluated under standardized conditions using anthropomorphic dummies such as those outlined in 14 CFR part 25. An example test involves decelerating one or more rows of seats and allowing a lap-belted dummy to impact components in front of it, which typically include the seatback and its integrated features. Examples of head contact surfaces include video monitors, a wide range of seat back materials, and airbags. The HIC, and other injury measures such as Nij, can be calculated during such impacts. A minimum test pulse, with minimum allowable acceleration vs time boundaries, is defined as part of the regulations for a frontal impact. In this study the effects of variations in decelerations that meet the requirements are considered. A series of Finite Element simulations of a generalized aircraft seat were performed to

Friedman, K, Mattos, G, Bui, K, Hutchinson, J, Jafri, A, Paver PhD, J

Tuning of Brake Force Distribution for Pickup Truck Vehicle LSPV Brake System During Cornering Maneuver

2017-01-2491

09/17/2017

Automotive industry has led to constant production innovation among manufactures. This has resulted in the reduction of the life cycle of the design philosophies and design tools. One of the performance factors that have continues to challenge automotive designer is to design and fine tune the braking performance with low cost and short life cycle. Improvement in braking performance and vehicle stability can be achieved through the use of braking systems whosebrake force distribution is variable. Braking force distribution has an important and serious role in thevehicle stopping distance and stability. In this paper a new approach will be presented to achieve the braking forcedistribution strategy for articulated vehicles. For this purpose, the virtual optimization process has beenimplemented. This strategy, defined as an innovative braking force distribution strategy, is based on the wheel slips.The simulation results illustrate proposed strategy can significantly improve the vehicle

Anthonysamy, Baskar, Prasad, Arun Kumar, Shinde, Babasaheb

Color Variable Speed Limit Sign Visibility for the Freeway Exit Driving Safety

2017-01-0085

03/28/2017

Typical vehicle speed deceleration occurs at the freeway exit due to the driving direction change. Well conducting the driver to control the velocity could enhance the vehicle maneuverability and give drivers more response time when running into potential dangerous conditions. The freeway exit speed limit sign (ESLS) is an effect way to remind the driver to slow down the vehicle. The ESLS visibility is significant to guarantee the driving safety. This research focuses on the color variable ESLS system, which is placed at the same location with the traditional speed limit sign. With this system, the driver could receive the updated speed limit recommendation in advance and without distraction produced by eyes contract change over the dashboard and the front sight. First, the mathematical model of the drivetrain and the engine brake is built for typical motor vehicles. The vehicle braking characteristics with various initial speeds in the deceleration area are studied. And then the brake

Xia, Wanyang, Wu, Yahui, Tan, Gangfeng, Ping, Xianyao, Liu, Benlong

Deceleration Rates of Vehicles with Disabled Tires

2017-01-1427

03/28/2017

Tire disablement events can cause a drag force that slows a vehicle. In this study, the magnitude of the deceleration was measured for different phases of 29 high speed tire tread separation and air loss tests. These deceleration rates can assist in reconstructing the speed of a vehicle involved in an accident following a tire disablement.

Koch, Daniel, Beauchamp, Gray, Pentecost, David

Integrated Systems Engineering Approach for Incremental 48Volt Hybrid Technology Introduction

2017-01-1603

03/28/2017

Automotive product engineering is highly complex. Understanding the implications and opportunities of introducing new technology needs to be identified as early as possible in the vehicle design process. These earlier design considerations have the potential to deliver right-first-time designs and maximize integration opportunities, resulting in efficient, effective, competitive and holistic design solutions. Integrating new technology into existing vehicle architectures can preclude and restrain the opportunity for engineers to invent, discover and deliver new design solutions. To avoid this potential loss of opportunity, it is necessary to trace back to vehicle-level assumptions and attributes to confirm the technology delivers the desired output. The vehicle and system analysis enables engineers to consider all vehicle attributes and how their sub-system can enhance other vehicle systems. This paper describes a case study using Function Analysis, within a systems engineering

Naidu, Ashish, Brittle, Peter, Ma, Xiaoyu, Rutter, Brian

A 0-D Calculation Template to Define Crush Space Requirement and Body Front End Force Level Requirement in Concept Stage

2017-26-0009

01/10/2017

Today’s automotive world has moved towards an age where safety of a vehicle is given the topmost priority. Many stringent crash norms and testing methodology has been defined in order to evaluate the safety of a vehicle prior to its launch in a particular market. If the vehicle fails to meet any of these criteria then it is debarred from that particular market. With such stringent norms and regulations in place it becomes quite important on the engineer’s part to define the structural requirements and protect the space to meet the same. If the concept level platform definition is done properly it becomes very easy to achieve the crash targets with less cost and weight impact. In our project a calculation methodology is presented in form of an excel based template that defines the crush space requirement in a vehicle and gives an insight to the designer regarding the force level that needs to be managed in the vehicle’s front end (assuming the uniform property of barrier) to meet the

Mohanty, Abhinab, Ramaraj, Rajasekar, Dhage, Prashant, Ray, Alok Kumar

Development of Fuzzy Based Decision Structure for Automotive Airbag Control Unit

2017-26-0349

01/10/2017

This study is an attempt to develop a decision support and control structure based on fuzzy logic for deployment of automotive airbags. Airbags, though an additional safety feature in vehicles, have proven to be fatal at various instances. Most of these casualties could have been avoided by using seat belts in the intended manner that is, as a primary restraint system. Fatalities can be prevented by induction of smart systems which can sense the presence and differentiate between passengers and conditions prevailing at a particular instant. Fuzzy based decision making has found widespread use due to its ability to accept non-binary or grey data and compute a reliable output. Smart airbags also allow the Airbag Control Unit to control inflation speed depending on instantaneous conditions. The objective of this study is to develop a decision system which could control a microcontroller using IF-THEN statements and thereby control and optimize airbag deployment speed depending on the

Batra, Rushil, Nanda, Sahil, Singhal, Shubham, Singari, Ranganath

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