Browse Topic: Stability control

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Experimental Study on Quality Control and Variable Valve Timing Strategy of Hydrogen Engine for High Efficiency and Low Emission at Low Load2024-01-509510/15/2024
In order to reduce the pumping loss of low loads and maximize the lean combustion advantage of hydrogen, the paper proposes a load control strategy based on hydrogen mass, called quality control, for improving thermal efficiency and emissions at low loads. The advantages of quality control and the effect of VVT on the combustion performance of hydrogen internal combustion engines under low loads were discussed. The results show that when the relative air–fuel ratio (λ) increases to more than 2.5, the NOx emissions are reduced to less than 3.5 g/kW · h at the brake mean effective pressure (BMEP) below 8 bar, especially when the BMEP is less than 5 bar, the NOx is within 0.2 g/kW · h. Compared to quantity control based on air mass, the quality control strategy based on hydrogen mass achieves over a 2.0% reduction in pumping loss at BMEP levels lower than 4.4 bar. Furthermore, it enhances thermal efficiency by up to 5% at low loads, while maintaining NOx emissions within 0.2 g/kW · h at
Li, Yong, Chen, Hong, Fu, Zhen, Du, Jiakun, Wu, Weilong
Recurrent Neural Network Model for On-Board Estimation of the Side-Slip Angle in a Four-Wheel Drive and Steering Vehicle15-17-01-000309/23/2023
Abstract A valuable quantity for analyzing the lateral dynamics of road vehicles is the side-slip angle, that is, the angle between the vehicle’s longitudinal axis and its speed direction. A reliable real-time side-slip angle value enables several features, such as stability controls, identification of understeer and oversteer conditions, estimation of lateral forces during cornering, or tire grip and wear estimation. Since the direct measurement of this variable can only be done with complex and expensive devices, it is worth trying to estimate it through virtual sensors based on mathematical models. This article illustrates a methodology for real-time on-board estimation of the side-slip angle through a machine learning model (SSE—side-slip estimator). It exploits a recurrent neural network trained and tested via on-road experimental data acquisition. In particular, the machine learning model only uses input signals from a standard road car sensor configuration. The model
Giuliacci, Tiziano Alberto, Ballesio, Stefano, Fainello, Marco, Mair, Ulrich, King, Julian
Recurrent Neural Network Model for On-Board Estimation of the Side-Slip Angle in a Four-Wheel Drive and Steering Vehicle15-17-01-0003-TEST-REC09/23/2023
Abstract A valuable quantity for analyzing the lateral dynamics of road vehicles is the side-slip angle, that is, the angle between the vehicle’s longitudinal axis and its speed direction. A reliable real-time side-slip angle value enables several features, such as stability controls, identification of understeer and oversteer conditions, estimation of lateral forces during cornering, or tire grip and wear estimation. Since the direct measurement of this variable can only be done with complex and expensive devices, it is worth trying to estimate it through virtual sensors based on mathematical models. This article illustrates a methodology for real-time on-board estimation of the side-slip angle through a machine learning model (SSE—side-slip estimator). It exploits a recurrent neural network trained and tested via on-road experimental data acquisition. In particular, the machine learning model only uses input signals from a standard road car sensor configuration. The model
Giuliacci, Tiziano Alberto, Ballesio, Stefano, Fainello, Marco, Mair, Ulrich, King, Julian
Improving Functionalities of Existing Electronic Stability Controller by adding Sensor Detection Based Algorithm for Collision Avoidance using CarSim.2022-01-116809/19/2022
With the advent of autonomous driving into mobility industry, passenger safety is of paramount importance. Electronic Stability Control (ESC) has been widely employed as an active safety feature in most of the modern cars, ESC is majorly based on differential braking, steer by wire or active torque distribution to prevent the vehicle from going off-course. However, ESC is limited to the discretion of the driver. Thus, the objective of this paper is to improve functionalities of existing electronic stability control by adding sensor detection-based algorithm for collision avoidance. The subject vehicle is installed with an existing default ESC & ABS system along with two range tracking sensors at front and rear and two blind spot detection sensors. The algorithm for collision avoidance has been tested in CarSim 2021.1. The procedure is tuned on different complex highway driving scenarios where a crate falls off from a traffic vehicle moving ahead of the subject vehicle along with
Shaikh, Parvez, Debnath, Sarnab, Kamble, Vijay, Mallikarjunaiah, Umesh
On-board estimation of road adhesion coefficient based on ANFIS and UKF2022-01-034703/29/2022
The road adhesion coefficient has a great impact on the performance of vehicle tires, which in turn affects vehicle safety and stability. A low coefficient of adhesion can significantly reduce the tire's traction limit. Therefore, the measurement of the coefficient is much helpful for automated vehicle control and stability control. Considering that the road adhesion coefficient is an inherent parameter of the road and it cannot be known directly from the information of the on-vehicle sensors. The novelty of this paper is to construct a road adhesion coefficient observer which considers the noise of sensors and measures the unknown state variable by the trained neural network. A Butterworth filter and Adaptive Neural Fuzzy Interference System (ANFIS) are combined to provide the lateral and longitudinal velocity which cannot be measured by regular sensors. Unscented Kalman filter (UKF) considering vehicle model, wheel model, and tire model is proposed to estimate the road adhesion
Chen, Zixuan, Duan, Yupeng, Wu, Jinglai, Zhang, Yunqing
Hierarchical Vehicle Stability Control Strategy Based on Unscented Kalman Filter Estimation2022-01-034303/29/2022
High-speed vehicle is prone to instability under bad road conditions, causing many safety accidents such as tail-flicking and overturning. Stability control could assist vehicle to drive safely and stably by adjusting the additional yaw moment. However, most of the existing stability control strategies directly invoke the information of the sideslip angle of the centroid that is difficult to obtain on the vehicle, and carry out complex controller design, which deviates from the actual application. In order to achieve a complete set of stability control architecture oriented to practical applications, this paper designs a hierarchical vehicle stability control strategy based on differential braking and state estimation technology. Firstly, a model oriented to state estimation and controller design is built according to the vehicle's motion state; Secondly, the sideslip angle of the centroid is accurately estimated through the unscented Kalman filter algorithm; Subsequently, the sliding
Zhang, Jian, Jiang, Hongwei, Li, Linrun, Liu, Qiuzheng, Wang, Yu, Liu, Jinbo, Gao, Yuan, Chen, Zhicheng
Empowering the Brake Systems2021-01-126110/11/2021
Some research shows that the transport system is one of the main responsible for the emission of pollutants in the atmosphere. The growing demand for automobiles contrasts directly with the scarcity of inputs, planet temperature increasing and air quality degradation in large cities. This counterpoint is explored and discussed a lot, demanding that studies would be conducted to find out sustainable solutions in the production to end-customers. Instead of use fossil resources, one of the options to reduce gas emissions is the use of vehicles powered by electricity. When converting part of the vehicle's kinetic energy into electrical one its reduces emissions in the production electricity - power plants - as well burning gases in transport. Technological advances allow us to use Electronic Stability Control to generate environmental and safety results in mobility for next years.
Batagini, Emerson
Monarch's automated, electric tractor ready for 2021 deliveries21TOFHP02_1002/01/2021
“If you want to fundamentally improve your economics,” said Monarch Tractor co-founder and CTO Zachary Omohundro to farmers and growers everywhere, “you go electric.” During a webcast with SAE International's Southern California Section featuring his startup company's battery-electric compact tractor, Omohundro offered markedly reduced operational costs as only one of many reasons for using the Monarch tractor, for which he said deliveries will start this fall for the “several hundred working farms” that have reserved the tractor that starts at $50,000.
Visnic, Bill
Applying Automotive EDR Data to Traffic Crash Reconstruction Virtual Pre-Conference CertificationC201608/07/2020
EDR\'s were first installed in 1994 and are now installed in 99% of new light vehicles sold in the US. In the US EDR’s are not required, but vehicles with EDR’s made after 9/1/2012 must meet minimum standardized content requirements of 49 CFR, Part 563 including speed, throttle, brake on/off and Delta V. Data must be retrievable with a publicly available tool. Only a few manufacturers install EDR’s worldwide currently, but the EU and China are adopting regulations to require them in the next few years. Some manufacturers provide stability control system data far beyond the US regulation that aid in understanding vehicle movement in the 5 seconds prior to the crash. This course will provide the participant with the skills necessary to analyze EDR data that has already been imaged, apply it to crash reconstruction, and reconcile it with calculations using other data sources. The course will enable the participant to analyze current and potential future EDR data set without regard to
Articulated Vehicle Lateral Stability Management via Active Rear-Wheel Steering of Tractor Using Fuzzy Logic and Model Predictive Control02-13-02-000807/01/2020
In-phase rear-wheel steering, where rear wheels are steered in the same direction of front wheels, has been widely investigated in the literature for vehicle stability improvements along with stability control systems. Much faster response can be achieved by steering the rear wheels automatically during an obstacle avoidance maneuver without applying the brakes where safe stopping distance is not available. Sudden lane change movements still remain challenging for heavy articulated vehicles, such as tractor and semitrailer combinations, particularly on roads with low coefficient of adhesion. Different lateral accelerations acting on tractor and semi-trailer may cause loss of stability resulting in jackknifing, trailer-swing, rollover, or slip-off. Several attempts have been made in the literature to use active steering of semi-trailer’s rear wheels to prevent jackknifing and rollover. However, loss of stability in an articulated vehicle is usually caused by an oversteered tractor, and
Sahin, Hasan, Akalin, Ozgen
Real-time and Accurate Estimation of Road Slope for Intelligent Speed Planning System of Commercial Vehicle2020-01-011504/14/2020
In the intelligent speed planning system, real-time estimation of road slope is the key to calculate slope resistance and realize the vehicles’ active safety control. However, if the road slope is measured by the sensor while the commercial vehicle is driving, the vibration of the vehicle body will affect its measurement accuracy. Therefore, the relevant algorithm is used to estimate the real-time slope of the road when the commercial vehicle is driving. At present, many domestic and foreign scholars have analyzed and tested the estimation of road slope by the least square method or Kalman filter algorithm. Although the two methods both can achieve the estimation, the real-time performance and accuracy still need to be improved. In this paper, for traditional fuel commercial vehicle, the Kalman filter algorithm based on the kinematics and the extended Kalman filter algorithm based on the longitudinal dynamics are respectively used to estimate the road slope. In the process of
Zhou, Mi, Tan, Gangfeng, Sun, Meng, Tian, Zhongpeng, Zhou, Fangyu, Liu, ZhiQiang
Effect of Stator Surface Area on Braking Torque and Wall Heat Dissipation of Magnetorheological Fluid Retarder2020-01-093704/14/2020
Magnetorheological fluid (MRF) is used as the transmission medium of the hydraulic retarder. The rheological properties are regulated by changing the magnetic field to achieve accurate control of the retarder's braking torque. Under the action of the external magnetic field, the flow structure and performance of the MRF retarder will be changed in a short time. The apparent viscosity coefficient increases by several orders of magnitude, the fluidity deteriorates and the heat generated by the brake cannot be transferred through the liquid circulation, which will affect the braking torque of the retarder. Changing the surface area of the stator also has an influence on the braking torque of the retarder and the wall heat dissipation. In this study, the relationship between the braking torque of the MRF retarder and the stator surface area of the retarder was analyzed. In addition, phase change materials were used to directly dissipate heat on the retarder surface to improve the heat
Liu, ZhiQiang, Tan, Gangfeng, Tian, Zhongpeng, Zhou, Mi, Agyeman, Philip, Frimpong, Justice
A Pre-Warning Method for Cornering Speed of Concrete Mixer Truck2020-01-100304/14/2020
The high gravity center of the concrete mixer truck reduces the truck’s stability while steering. The rolling stirring tank makes the stability even worse than the regular engineering vehicle due to the dynamic variation of the centroid position. Most of the researches on the rollover stability of concrete mixer trucks focus on the rollover model establishment and dynamic simulation module. The change of concrete centroid is ignored when the safety cornering speed is calculated. This paper proposes a pre-warning method for the cornering speed of concrete mixer trucks based on centroid dynamic simulation. In the method, the mixing tank stirring model and the vehicle driving dynamic model are established on the Fluent and TruckSim simulation platforms, respectively. The theoretical speed threshold obtained by simulation is used as the evaluation index of the warning speed in the curve. Firstly, the dynamic simulation of the stirring tank model is carried out by Fluent. According to
Jiang, Yifeng, Tan, Gangfeng, Wang, Haoyu, Wang, Zelong, Wang, Zhenyu, Li, Ming
A Novel Kalman Filter Based Road Grade Estimation Method2020-01-056304/14/2020
Accurate, robust and real-time estimation of road grade is extremely important in vehicle control (battery management, transmission shift scheduling, distance-to-empty prediction, anti-lock braking system, collision avoidance, stability control, etc.) to improve safety, stability, efficiency and performance. This paper presents a novel Kalman filter based road grade estimation method using measurements from an accelerometer, gyroscope and tachometer. The accelerometer measures the components of the vehicle acceleration (including the components of the acceleration due to gravity), and the measurements provided by the accelerometer are almost drift free but heavily corrupted by measurement noises. The gyroscope measures the components of the angular velocity of the vehicle, and the measurements provided by the gyroscope are quite clean but disturbed by gyroscope biases. The tachometer measures the longitudinal vehicle velocity, and the measurement provided by the tachometer is also
Gokcek, Cevat
Requirements for Road Weather ApplicationsJ2945/3_202003 (Historical)03/24/2020
Inclement weather can have a significant impact on surface transportation systems. It can result in hazardous conditions for travelers due to poor visibility, or wet or icy roadways. Weather applications have the potential to provide additional data to surface transportation infrastructure owners and operators, allowing them to better assess the impacts of the weather environment on or around the roadway and to better manage the surface transportation system. Such weather applications can: Collect road weather data from connected vehicles and mobile devices, increasing the number of data sources available. Provide road weather related traveler information to travelers via connected vehicles and devices, such as when and where a hazardous condition exists. Provide the ability to manage road weather response on specific roadways. This SAE Standard specifies interface requirements between vehicles and infrastructure for weather applications, including detailed systems engineering
Infrastructure Applications Technical Committee
An Efficient, High-Precision Vehicle Testing Procedure to Evaluate the Efficacy of Fuel-Borne Friction Modifier Additives2019-01-235312/19/2019
Improved fuel economy is increasingly a key measure of performance in the automotive industry driven by market demands and tighter emissions regulations. Within this environment, one way to improve fuel economy is via fuel additives that deliver friction- reducing components to the piston-cylinder wall interface. Whilst the use of friction modifiers (FMs) in fuel or lubricant additives to achieve fuel economy improvements is not new, demonstrating the efficacy of these FMs in vehicles is challenging and requires statistical design together with carefully controlled test conditions. This paper describes a bespoke, efficient, high-precision vehicle testing procedure designed to evaluate the fuel economy credentials of fuel-borne FMs. By their nature, FMs persist on engine surfaces and so their effects are not immediately reversible upon changing to a non FM-containing fuel (“carryover” effect), therefore requiring careful design of the test programme. The solution presented here
Yow, Shuhui, Ziman, Pauline, Smith, Sue J., Walter, Dr. Marc, Bacchi, Robert J.
Axle Torque Distribution to Improve Vehicle Handling and Stability2019-01-503711/04/2019
The majority of the fully electric vehicles currently on the market have a basic drivetrain configuration, consisting of multiple electric motors, which promise considerable performance enhancements in terms of vehicle behavior and active safety. A significant advantage was achieving measurable benefits in terms of vehicle cornering response through controlling the individual drivetrains. This paper presents an axle torque distribution method to improve a 4WD vehicle steering performance. The method can automatically adjust the output drive torque of the front and rear motors of the vehicle to change the vehicle yaw rate before ESP intervention, and at the same time remain the driver torque demand unchanged. In this paper we present a feedback yaw rate controller. When the estimated yaw rate differs from the actual yaw rate with a pre-defined small threshold, a yaw rate control is active, the purpose of the controller is to reduce the vehicle understeer characteristic. The simulation
Wu, Aibin, Li, Chao, Zhao, Yongqiang, Cui, Jinlong
Analysis of Active Collision Avoidance Performance Based on Cooperative Regenerative Auxiliary Braking System2019-01-502711/04/2019
Active collision avoidance can assist drivers to avoid longitudinal collision through active brake. Regenerative braking can improve the driving range and braking response speed. At this stage, conventional hydraulic braking system limits the implements of above technologies because of its poor performance of response speed and coordinated control. While the brake-by-wire system is a better actuator that can fulfill requirements of automotive electric and intelligent development due to its rapid response and flexible adjustment. However, the system control algorithm becomes more complicated with introduction of regenerative braking and active collision avoidance function, which is also the main problem solved in this paper. First, a new type of cooperative regenerative auxiliary braking system (CRABS) of intelligent electric vehicles, which integrates the functions of brake-by-wire, regenerative braking and active collision avoidance, is proposed, for purpose of analyzing the
Hou, Xiaohui, Zhang, Junzhi, Zhang, Zhongshi, He, Chengkun
Braking Requirements for Optimizing Autonomous Emergency Braking Performance2019-01-212709/15/2019
Vehicle technology new developments have contributed to improve vehicle structural performance and therefore passive protection, but also the inclusion of electronic control units has provided new opportunities to expand active safety systems. This is the case for systems like anti-lock braking systems (ABS), electronic stability control (ESC) and brake assist (BA) among others. A more advanced generation of active systems includes sensorial units that monitor vehicle’s surrounding and detect potential hazards, such as an imminent collision, and performs an automatically and commanded emergency braking to lessen or mitigate the consequences of the impending accident. For this latest system, the so-called autonomous emergency braking (AEB), various consumer testing protocols, such as Euro NCAP protocols [1], propose and periodically update test catalogues in order to evaluate the performance of such systems and later to inform potential consumers. The aim of this study is to investigate
Esquer Molina, Álvaro, Bargallo, Jordi
Comparative Analysis between American and European Requirements for Electronic Stability Control (ESC) Focusing on Commercial Vehicles2019-01-214109/15/2019
Analysis of road accidents has shown that an important portion of fatal crashes involving Commercial Vehicles are caused by rollovers. ESC systems in Commercial Vehicles can reduce rollovers, severe understeer or oversteer conditions and minimize occurrences of jackknifing events. Several studies have estimated that this positive effect of ESC on road safety is substantial. In Europe, Electronic Stability Control (ESC) is expected to prevent by far the most fatalities and injuries: about 3,000 fatalities (-14%), and about 50,000 injuries (-6%) per year. In Europe, Electronic Stability Control Systems is mandatory for all vehicles (since Nov. 1st, 2011 for new types of vehicle and Nov. 1st, 2014 for all new vehicles), including Commercial Vehicles, Buses, Trucks and Trailers. On 2015, NHTSA published Federal Motor Vehicle Safety Standard (FMVSS) No. 136, Electronic Stability Control systems for heavy vehicles, requiring Electronic Stability Control (ESC) systems on truck tractors and
Iombriller, Silvia Faria, Bolognesi Prado, Wesley, Silva, Marco Andre
The Rodney Dangerfield of Automated-Driving Sensors19AVEP07_0607/01/2019
Radar and lidar get all the attention, but Inertial Measurement Units are the backbone of sensor fusion. Suppliers are scrambling to make IMUs more accurate-and much less expensive. The emerging era of highly-automated driving comes courtesy of much-vaunted sensor technology-spinning lasers, penetrating radar, sonar blips. But the sensor that gets the least respect in the technology stack could be the lynchpin for the mass roll-out of self-driving vehicles: the inertial measurement unit (IMU). “IMUs are the glue that binds everything together,” said Mike Horton, chief technology officer at Aceinna, a Boston-based company that develops sensing solutions for automotive applications. “An IMU can help bring different types of data together from GNSS (Global Navigation Satellite System), lidar and cameras to make everything consistent and smooth.”
Berman, Bradley
Jeep revives its pickup mojo with 2020 Gladiator19AUTP05_1505/01/2019
Get ready for the fractionalization of the U.S.'s raucous pickup-truck market. Launching what's surely one of the year's most-anticipated and potentially significant new models, Jeep engineers and planners insist they went out of their way to ensure the 2020 Gladiator was developed as a genuine pickup and not “a Wrangler with a bed.” But everyone knows Jeep would've been crazy to stray too far from the radiant demand for the new JL-generation Wrangler, so excuse us if the Gladiator does, well, at least look like just that: a 4-door Wrangler Unlimited-with a bed.
Visnic, Bill
GPU Implementation for Automatic Lane Tracking in Self-Driving Cars2019-01-068004/02/2019
The development of efficient algorithms has been the focus of automobile engineers since self-driving cars become popular. This is due to the potential benefits we can get from self-driving cars and how they can improve safety on our roads. Despite the good promises that come with self-driving cars development, it is way behind being a perfect system because of the complexity of our environment. A self-driving car must understand its environment before it makes decisions on how to navigate, and this might be difficult because the changes in our environment is non-deterministic. With the development of computer vision, some key problems in intelligent driving have been active research areas. The advances made in the field of artificial intelligence made it possible for researchers to try solving these problems with artificial intelligence. Lane detection and tracking is one of the critical problems that need to be effectively implemented. The ability of a self-driving car to
Yusuf, Ayomide, Alawneh, Shadi
Pressure Estimation Algorithms in Decoupled Electro-Hydraulic Brake System Considering the Friction and Pressure-Position Relationship2019-01-043804/02/2019
This paper presents several pressure estimation algorithms (PEAs) for a decoupled electro-hydraulic brake system (EHB), which is driven by an electric motor + reduction gear. Most of the pressure control solutions are based on standard pressure-based feedback control, requiring a pressure signal. Although the pressure sensor can produce the pressure feedback signal, it will increase cost and enlarge installation space. The rotation angle of electric motor is available by the built-in sensor, so the pressure can be estimated by using the rotation angle. Considering the typical nonlinearities (i.e. friction, pressure-position relationship) and uncertainties (i.e. disturbance caused by friction model), the estimation-oriented model is established. The LuGre model is selected to describe the friction, and the pressure-position relationship is fitted by a quadratic polynomial. Based on the estimation-oriented model, the force-based PEA (FPEA) and the interconnected PEA (IPEA) are designed
Han, Wei, Xiong, Lu, Yu, Zhuoping
Safety and Lateral Dynamics Improvement of a Race Car Using Active Rear Wing Control2019-01-064304/02/2019
As the forward speed of a car increases, the safety of the vehicle and the driver becomes a more significant concern. Active aerodynamic control can effectively enhance the lateral stability of high speed vehicles over tight cornering maneuvers. A split rear wing has been proposed. By means of manipulating the attack angles for the right and/or left parts of the split rear wing, a favorable yaw moment may be achieved to ensure the lateral stability of the vehicle. However, active control of the split rear wing has not been adequately explored. This paper proposes a novel active split rear wing, which can improve the lateral stability over tight cornering maneuvers, and will not degrade the longitudinal dynamics of the vehicle. A Linear Quadratic Regulator (LQR) based controller for the active split rear wing is designed using a linear vehicle model. In order to examine the performance of the active split rear wing, Numerical simulation is carried out using the LQR based controller and
Hammad, Mohammed, Qureshi, Khizar, He, Yuping
Road Tested19AVEP03_1103/01/2019
Transportation-infrastructure expert Kirk Steudle reflects on the rapid progress toward the connected-AV future and the challenges ahead. In the auto industry, mechanical and electrical engineers work from the tire up. Civil engineers work from the tire down,” quips Kirk Steudle. “And although it's taken a while for both to understand each other's jargon, the connected-and-autonomous vehicle is forcing them all together-to solve problems for society's mobility.” Steudle, a registered professional engineer, has been at the vehicle-to-road nexus his entire career. Last October he retired as director of the Michigan Dept. of Transportation where, among many achievements, his leadership helped put the state and its core industry in the vanguard of connected-car and AV-related developments, testing, and infrastructure standards. During his final year at MDoT, he also served as interim CEO of the American Center for Mobility, the new 500-acre AV proving ground and test center near Ann Arbor.
Brooke, Lindsay
WHAT WE'RE DRIVING19AUTP03_0903/01/2019
When the Tribeca, Subaru's first shot (2009) at a three-row SUV, didn't quite deliver the goods in this brutally competitive segment and went away in 2014, Fuji Heavy planners went right to work on the replacement-the all-new Ascent. It's more aesthetically pleasing, boasts a lighter and stiffer global architecture (long-wheelbase version of the latest Impreza sedan) and is better-designed and -equipped inside. The Ascent Premium is the first price-walk up from the base car. The one I tested stickered at $39,430, outfitted with a moonroof and comprehensive ‘Starlink’ navi-tainment suite worth $4,200. Standard Ascent propulsion comes from Subaru's 2.4-L flat-four gasoline engine, turbocharged to deliver 260 hp (194 kW). It's coupled with Fuji's own TR690 CVT and torque-vectoring AWD, all capable of pulling a 5,000-lb (2268-kg) trailer. While I did not tow during my time with the Ascent, under normal loads and hard acceleration the ‘boxer’ engine and CVT can be comparatively noisy and
Movement Prediction Hypotheses for Pedestrians and Trajectory Planning for Cooperative Driving Systems12-02-01-000212/19/2018
It is a challenge to find a safe trajectory for automated vehicles in urban environments with pedestrians. The prediction of future movements with 100% certainty is impossible, if the intention is unknown. A Gaussian process approach is used to formulate future movement hypotheses of the pedestrian based on historical movements. A mixed integer linear programming (MILP) optimization approach is used for the trajectory planning of the vehicle. The collision probability between the ego-vehicle and pedestrian is used as constraints in the optimization. This approach is useful for cooperative vehicle systems, with historical movement data in a fixed urban environment (e.g., intersection) and the premise that pedestrians follow typical movement data.
Hartmann, Michael, Stolz, Michael, Watzenig, Daniel
Dedicated Short Range Communications (DSRC) Performance Requirements for V2V Safety AwarenessJ2945/2_201810 (Current)10/30/2018
This SAE Document specifies DSRC interface requirements for V2V Safety Awareness applications, including detailed Systems Engineering documentation (needs and requirements mapped to appropriate message exchanges). These applications include: Emergency Vehicle Alert, Roadside Alert, and Safety Awareness Alerts for Objects and Adverse Road Conditions. This document extends the V2V Communications capabilities defined in J2945/1 to support these applications, and the National ITS Architecture. The purpose of this SAE Document is to enable interoperability for V2V Safety Awareness communications.
V2X Vehicular Applications Technical Committee
Trajectory-Tracking Control for Autonomous Driving Considering Its Stability with ESP2018-01-163908/07/2018
With rapid increase of vehicles on the road, safety concerns have become increasingly prominent. Since the leading cause of many traffic accidents is known to be by human drivers, developing autonomous vehicles is considered to be an effective approach to solve the problems above. Although trajectory tracking plays one of the most important roles on autonomous driving, handling the coupling between trajectory-tracking control and ESP under certain driving scenarios remains to be challenging. This paper focuses on trajectory-tracking control considering the role of ESP. A vehicle model is developed with two degrees of freedom, including vehicle lateral, and yaw motions. Based on the proposed model, the vehicle trajectory is separated into both longitudinal and lateral motion. The coupling effect of the vehicle and ESP is analyzed in the paper. The lateral trajectory-tracking algorithm is developed based on the preview follower theory. Spacing control strategy is used in longitudinal
Pan, Fei, Deng, Weiwen, Zhang, Sumin, Wang, Jinsong, Wang, Shanshan
Consideration of Effective Chassis Control in Electric Vehicle2018-01-503508/06/2018
In this study, we focus on “camber angle control” and “derivative steering assistance” using “steer-by-wire” as maneuverability and stability improvement techniques that are appropriate for the electric vehicle (EV) era. Movements that produce a negative camber angle generate camber thrust, and vehicle motion performance improvements extend from the fact that the tire side force is increased by the camber thrust effect. In our experimental vehicle, a proportional steering angle system was used to create negative camber angle control via an electromagnetic actuator that allowed us to confirm improvements to both the effectiveness and stability of steering control in restricted cornering areas. More specifically, we determined that it is possible to improve critical cornering performance by executing ground negative camber angle control in proportion to the steering angle. Steer-by-wire refers to an electrical steering technique that allows the steering angle of the entire vehicle to be
Yamaguchi, Ryo, Nozaki, Hiromichi
2021-12-29.TEST Mitigating Unknown Cybersecurity Threats in Performance Constrained Electronic Control Units2018-01-001604/03/2018
Externally-connected Electronic Control Units (ECUs) contain millions of lines of code, which may contain security vulnerabilities. Hackers may exploit these vulnerabilities to gain code execution privileges, which affect public safety. Traditional Cybersecurity solutions fall short in meeting automotive ECU constraints such as zero false positives, intermittent connectivity, and low performance impact. A desirable solution would be deterministic, require minimum resources, and protect against known and unknown security threats. We integrated Autonomous Security on a BeagleBone Black (BBB) system to evaluate the feasibility of mitigating Cybersecurity risks against potential threats. We identified key metrics that should be measured, such as level of security, ease of integration and system performance impact. In this paper, we describe the integration and evaluation process and present its results. We show that Autonomous Security can provide this protection with zero false-positives
Harel, Assaf, Ben David, Tal, Kashani, Ameer, Iyer, Gopalakrishnan, Motonori, Ando, Masumi, Egawa
The Influence of Autonomous Driving on Passive Vehicle Dynamics2018-01-055104/03/2018
Traditional vehicles are designed to be inherently stable. This is typically obtained by imposing a large positive static margin (SM). The main drawbacks of this approach are the resulting understeering behavior of the vehicle and, often, a decrease in peak lateral grip due to oversized rear tire characteristics. On the other hand, a lower SM can cause a greater time delay in the vehicle’s response which hardens the control of a vehicle at limit handling for a human being. By introducing advanced autonomous driving features into future vehicles, the human factor can be excluded in limit handling manoeuvers (e.g., obstacle avoidance occurrences) and, consequently, the need for a high SM (i.e., high controllability for human drivers) can be avoided. Therefore, it could be possible to exploit the passive vehicle dynamics and enhance the performance, both in terms of peak grip and transient response. The goal of this article is to explore if a decrease in SM can lead to a performance
Novi, Tommaso, Liniger, Alex, Capitani, Renzo, Fainello, Marco, Danisi, Giacomo, Annicchiarico, Claudio
Vehicle Sideslip Angle Estimation: A Review2018-01-056904/03/2018
Vehicle sideslip angle estimation is of great importance to the vehicle stability control as it could not be measured directly by ordinary vehicle-mounted sensors. As a result, researchers worldwide have carried out comprehensive research in estimating the vehicle sideslip angle. First, as the attitude would affect the acceleration information measured by the IMU directly, different kinds of vehicle attitude estimation methods with multi-sensor fusion are presented. Then, the estimation algorithms of the vehicle sideslip angle are classified into the following three aspects: kinematic model based method, dynamic model based method, and fusion method. The characteristics of different estimation algorithms are also discussed. Finally, the conclusion and development trend of the sideslip angle estimation are prospected.
Liu, Wei, Xiong, Lu, Xia, Xin, Yu, Zhuoping
Evaluation of Alternative Steering Devices with Adjustable Haptic Feedback for Semi-Autonomous and Autonomous Vehicles2018-01-057204/03/2018
Emerging autonomous driving technologies, with emergency navigating capabilities, necessitates innovative vehicle steering methods for operators during unanticipated scenarios. A reconfigurable “plug and play” steering system paradigm enables lateral control from any seating position in the vehicle’s interior. When required, drivers may access a stowed steering input device, establish communications with the vehicle steering subsystem, and provide direct wheel commands. Accordingly, the provision of haptic steering cues and lane keeping assistance to navigate roadways will be helpful. In this study, various steering devices have been investigated which offer reconfigurability and haptic feedback to create a flexible driving environment. A joystick and a robotic arm that offer multiple degrees of freedom were compared to a conventional steering wheel. To evaluate the concept, human test subjects interacted with the experimental system featuring a driving simulator with target hardware
Wang, Chengshi, Wang, Yue, Wagner, John R.
Vehicle Sideslip Angle Estimation Considering the Tire Pneumatic Trail Variation2018-01-057104/03/2018
Vehicle sideslip angle is significant for electronic stability control devices and hard to estimate due to the nonlinear and uncertain vehicle and tire dynamics. In this paper, based on the two track vehicle dynamic model considering the tire pneumatic trail variation, the vehicle sideslip angle estimation method was proposed. First, the extra steering angle of each wheel caused by kinematics and compliance characteristics of the steering system and suspension system was analyzed. The steering angle estimation method was designed. Since the pneumatic trail would vary with different tire slip angle, distances between the center of gravity (COG) and front&rear axle also change with the tire slip angle. Then, based on the dynamic pneumatic trail and estimated steering angle, we modified the traditional two track vehicle dynamic model using a brush tire model. This model matches the vehicle dynamics more accurately. In addition, we designed two extended Kalman filters (EKF) based on the
Xia, Xin, Xiong, Lu, Lin, Xuefeng, Yu, Zhuoping
Research on Regenerative Braking Control Strategy of Distributed EV based on Braking Intention2018-01-134204/03/2018
Focusing on distributed electric vehicles with in-wheel motors, a novel regenerative braking control strategy based on braking intention is proposed. Firstly, a design scheme for the regenerative braking system is described. Four in-wheel motors and an Electro-Hydraulic Braking (EHB) system are respectively designed for regenerative braking and hydraulic braking. Then, Braking intention recognition self-learning libraries are trained based on Hidden Markov Model method, which is validated by driver-in-loop tests. According to three speed states and four braking intentions, the regenerative braking control strategy for multiple brake modes is developed. The coefficient of regenerative braking is defined to describe the intervening time and proportion of motor maximum regenerative braking. Eventually, the co-simulation results show that the proposed strategy can not only significantly improve the energy recovery capability, but also provide the coordinated control of regenerative braking
Pan, Hao, Guo, Xuexun, Pei, Xiaofei, Pan, Jin, Zhang, Jie
Integrated Chassis Control for Vehicle Stability under Various Road Friction Conditions2018-01-055204/03/2018
This paper presents an integrated chassis control method for vehicle stability under various road friction conditions without information on tire-road friction. For vehicle stability, vehicle with an integrated chassis control needs to cope with the various road friction conditions. One of the chassis control method under various road conditions is to determine and/or limit control inputs based on tire-road friction coefficient. The tire-road friction coefficient, however, is difficult to estimate and still a challenging task. The key idea for the proposed method without the estimation of the tire-road friction coefficient is to analyze and control vehicle states based on a tire slip angle - tire force phase plane, i.e. based on these vehicle responses: tire forces and tire slip angles of front/rear wheels. Based on the phase plane, vehicle instability is detected and the vehicle is controlled to regain the vehicle stability and maneuverability under various road conditions without
Joa, Eunhyek, Yi, Kyongsu, Bae, Hyungjune, Sohn, Kimo
A Braking Force Distribution Strategy in Integrated Braking System Based on Wear Control and Hitch Force Control2018-01-082704/03/2018
A braking force distribution strategy in integrated braking system composed of the main braking system and the auxiliary braking system based on braking pad wear control and hitch force control under non-emergency braking condition is proposed based on the Electronically Controlled Braking System (EBS) to reduce the difference in braking pad wear between different axles and to decrease hitch force between tractors and trailers. The proposed strategy distributes the braking force based on the desired braking intensity, the degree of the braking pad wear and the limits of certain braking regulations to solve the coupling problems between braking safety, economical efficiency of braking and the comfort of drivers. Computer co-simulations of the proposed strategy are performed. The braking force distribution strategy is verified under condition of equal wear of braking pad, condition of greater wear on the front axle of tractor and condition of greater wear on the rear axle of the tractor
Zheng, Hongyu, Liu, Chen, Wang, Linlin
Autonomous Robotic Self-RightingTBMG-2869904/01/2018
Robots are increasingly being used for various applications including search and rescue operations and combat situations. Unfortunately, during the performance of maneuvers, a robot may fall or tip over, preventing it from moving normally. Controlling the robot to successfully right itself can be a difficult and time-consuming task for operators — a major problem in situations that may be both time-sensitive and dangerous; for example, those controlling the robot must determine how to re-orient the robot to a desired position, if it is possible.
Automotive Stability Enhancement SystemsJ2564_201711 (Current)11/14/2017
The purpose of this SAE Information Report is to describe currently known automotive active stability enhancement systems, as well as identify common names which can be used to refer to the various systems and common features and functions of the various systems. The primary systems discussed are: a ABS - Antilock Brake Systems b TCS - Traction Control Systems c ESC - Electronic Stability Control The document is technical in nature and attempts to remain neutral regarding unique features that individual system or vehicle manufacturers may provide.
Vehicle Dynamics Standards Committee
M xDrive: BMW's power + grip solution17AUTP11_1311/01/2017
Channeling 591 hp (441 kW) and 553 lb·ft (750 N·m) through a pair of hand-sized contact patches was always going to be a challenge, even for the engineers at BMW's M division. “Four years ago we knew we had to find the right solution for the sixth-generation M5 since it was going to have a considerable power hike,” Dirk Hacker, Vice President Engineering for the M division told Automotive Engineering at the 2017 Frankfurt Motor Show.
Adcock, Ian
Local Path Planning for Intelligent Vehicle Obstacle Avoidance Based on Dubins Curve and Tentacle Algorithm2017-01-195109/23/2017
Local path planning for obstacle avoidance is one of the core topics of intelligent vehicle. A novel method based on dubins curve and tentacle algorithm is proposed in this article, with the consideration of obstacle avoidance and vehicle motion constraints. First, the preview distance of the vehicle is given according to the current speed, so that the preview point can be found with the information of global path. Then dubins curve is adopted to find a path with appropriate turning radius, between the current position and preview point, satisfying the constraints of current direction and target direction, considering handling and ride comfort of the vehicle. In order to avoid obstacle, tentacle algorithm is adopted. 20 tentacle points are given by moving the original preview point, and then 21 local paths can be given by using dubins curve. Cost function is used to find out the best option of the 21 paths. The distance to obstacle, the final distance to original preview point and the
Wu, Lingfei, Zha, Hongshan, Xiu, Caijing, He, Qiaojun
Development and Validation of the SAE J3052 High Pressure Differential Flow Rate Recommended Practice2017-01-249809/17/2017
This paper describes the development work that went into the creation of the SAE J3052 “Brake Hydraulic Component Flow Rate Measurement at High Delta Pressure”, and also shows some example applications. The SAE J3052 recommended practice is intended to measure flow characteristics through brake hydraulic components and subsystems driven by pressure differentials above 1 bar, and was anticipated by the task force to be invoked for components and subsystems for which pressure response characteristics are critical for the operation of the system (such as service brake pressure response and stopping distance, or pressure rise rate of a single hydraulic circuit in response to an Electronic Stability Control command). Data generated by this procedure may be used as a direct assessment of the flow performance of a brake hydraulic component, or they may be used to build subsystem or system-level models. Two significant variants of test methodology were studied, including use of a servo
Antanaitis, David B., Lloyd, E
The Design and Evaluation of EMB Actuator Scheme2017-01-250909/17/2017
Electromechanical Braking System (EMB) stops the wheel by motor and related enforce mechanism to drive braking pads to clamp the friction plate. It is compact in sized as well as faster in response, which solves the issue of potential leakage and slows response of traditional hydraulic brake system. The institutions at home and abroad have put forward all kinds of new structural schemes of EMB. At present, there are various EMB structural schemes, but the analysis and evaluation of these schemes are relatively few. In this paper, on the basis of a large number of research, the EMB actuator is modular decomposed according to function ,then the parametric 3D model library of each function module is established. According to brake requirements of the target vehicle, a development platform is set up to match EMB actuator structure scheme quickly. Moreover, the analysis and evaluation of several typical schemes are accomplished by analytic hierarchy process, providing reference for
Zhuo, Guirong, Xue, Ruonan, Zhang, Subin, Wu, Cheng, Xiong, Kun
Pressure Following Strategy for Conventional Braking Control Applied to a HIL Test Bench2017-01-249609/17/2017
Brake systems represent important components for passenger cars since they are strictly related to vehicle safety: Anti-lock Braking Systems (ABS) and Electronic Stability Control (ESC) are the most well-known examples. The paper is focused on the characterization of the braking hydraulic plant and on the design of a pressure following control strategy. This strategy is aimed at pursuing performances and/or comfort objectives beyond the typical safety task. The low-level logic (focus of the paper) consists of a Feedforward and Proportional Integral controller. A Hardware In the Loop (HIL) braking test bench is adopted for pressure controller validation by providing some realistic reference pressure histories evaluated by a high-level controller. Results prove that innovative control strategies can be applied to conventional braking systems for achieving targets not limited to braking issues, i.e., comfort or NVH tasks.
Galvagno, Enrico, Tota, Antonio, Vigliani, Alessandro, Velardocchia, Mauro
Brake System Regulations and Standards Review and Comparison Focused on Europe, NA and SA Markets2017-01-253409/17/2017
Considering that the most part of commercial vehicles are equipped with air brakes it is very important assure specific technical requirements for air brake system and its components. In addition, the effects of brake system failure are more critical for commercial vehicles which require more attention on their requirements details. Historically, the development of air brakes technology started on North America and Europe and consequently two strong and distinct resolutions were structured: FMVSS 121 and ECE R.13, respectively. For passenger cars were developed the ECER.13H to harmonize North American and European resolutions. However, for commercial vehicles regional applications, culture and implementation time must be considered. These commercial vehicles peculiarities must be understood and their specific requirements harmonized to attend the global marketing growth. This article shows a review of the North American and European air brake requirements and also discusses their
Iombriller, Silvia Faria, Bolognesi Prado, Wesley
Road-efficient mud machine17AUTP04_0504/01/2017
Jeep's all-new 2017 Compass gets its go-anywhere guts from GKN's AWD system. Replacing the decade-old Jeep Compass is the new-for-2017 Compass, FCA's (and Jeep's) first truly global vehicle program. Styled to resemble a slightly scaled-down Grand Cherokee, the new C-segment SUV is being produced in four plants (Mexico, China, India and Brazil) and offered in 17 powertrain combinations that include diesels and 6-speed manual gearboxes. The U.S. gets the manual ‘box but not the diesel. The new Compass is based on a stretched version of FCA's so-called “small-wide 4×4” vehicle architecture that also underpins the smaller Jeep Renegade. That platform is designed primarily as front-wheel-drive and accommodates nicely the axle-disconnect all-wheel-drive system supplied by GKN (see sidebar). As a “4.4-meter” car designed to fit European and other global parking spaces, the Jeep's overall length is 173 in (4394 mm), riding on a 103.8 in (2636 mm) wheelbase.
Brooke, Lindsay
Reduction of Steering Effort in the Event of EPAS Failure using Differential Braking Assisted Steering2017-01-148903/28/2017
Electric Power Assisted Steering (EPAS) is widely adopted in modern vehicles to reduce steering effort. It is probable that some EPAS systems will experience a shutdown due to reliability issues stemming from electrical and/or electronic components. In the event of EPAS failure, power assist becomes unavailable and the steering system reverts to a fully manual state, leading to excessive steering torque demands from the driver to maneuver the vehicle at lower speeds, i.e., under 30 mph. This situation has resulted in dozens of reported crashes and several OEM safety recalls in the past few years. Inspired by recent work which utilizes independent driving torque of in-wheel-motor vehicles to reduce steering torque, this paper proposes the use of Differential Braking Assisted Steering (DBAS) to alleviate steep increases in steering torque upon EPAS failure. DBAS requires software upgrades with minimal hardware modification to EPAS, which is preferable for a backup system. A preliminary
Zhang, Duanxiang, Lin, Bo, Kirli, Ahmet, Okwudire, Chinedum
An Advanced Yaw Stability Control System2017-01-155603/28/2017
This paper presents an advanced yaw stability control system that uses a sensor set including an inertial measurement unit to sense the 6 degrees-of-freedom motions of a vehicle. The full degree of the inertial measurement unit improves and enhances the vehicle motion state estimation over the one in the traditional electronic stability controls. The addition of vehicle state estimation leads to the performance refinement of vehicle stability control that can improve performance in certain situations. The paper provides both detailed system description and test results showing the effectiveness of the system.
Lu, Jianbo, Xu, Li, Eisele, Daniel, Samuel, Stephen, Rupp, Matthew, Tellis, Levasseur
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