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Technical Paper

A Statistical Method to Substructure Crash Simulation Model

2021-12-03
2021-01-5107
This work presents a statistical method to use a portion of a full finite element vehicle model on a crash analysis event. The substructure model is linked to the full model by recording the interface boundary history. The lateral moving deformable barrier (MDB) test by the Insurance Institute for Highway Safety (IIHS) is used to demonstrate this substructure method: Substructure portion is identified by energy absorption distribution, and noise elements are filtered out by density-based spatial clustering of applications with noise (DBSCAN), a nonsupervised machine learning method. Crashworthiness simulation is performed in LS-DYNA software, and results between substructure vehicle model, full vehicle model, and physical vehicle test results are compared. It shows the result from the substructure model is more effective without accuracy compromise.
Research Report

Unsettled Issues in Commercial Vehicle Platooning

2021-11-15
EPR2021027
While platooning has the potential to reduce energy consumption of commercial vehicles while improving safety, both advantages are currently difficult to quantify due to insufficient data and the wide range of variables affecting models. Platooning will significantly reduce the use of energy when compared to trucks driven alone, or at a safe distance for a driver without any automated assistance. However, drivers typically drive closer to each other than recommended to achieve drafting efficiencies, which may shift the benefit of automated platooning to safety gains. More data will be needed to conclusively demonstrate these gains. Unsettled Issues in Commercial Vehicle Platooning discusses the technologies needed to enable close platooning, including brake system condition monitoring, vehicle-to-vehicle communication, and concrete infrastructure assessment. The report also looks at driver acceptance of platooning technology from a safety and job security perspective.
Technical Paper

Measurement Methods for Radar Cross Section of Passenger Vehicles

2021-11-09
2021-01-5103
Automotive millimeter-wave radar is used extensively in vehicle active safety. The Radar Cross Section (RCS) is one of the main parameters used by the automotive radar system to detect and identify surrounding vehicles. The RCS describes the electromagnetic scattering properties of objects. This paper describes a method and equipment to measure the RCS. An automobile-grade radar is used to measure the RCS of typical vehicles. A representative distance between the radar and the vehicle was chosen based on the analysis of the RCS of passenger vehicles in different distances in the near field. A cost-effective rotating platform was developed to rotate the passenger vehicles for RCS measurement in different azimuth angles. The RCS generated by the rotating platform was analyzed and mitigated. The measurement system can record the synchronized azimuth angle and RCS measurement.
Technical Paper

Electrician Demand for Battery Electric Vehicle Charger Installation

2021-11-03
2021-01-5102
Demand for electricians was estimated based on projected increases in battery electric vehicle (BEV) sales. Total BEV sales were projected from current producer plans. Each scenario for charger type and charging location requires different combinations of electrical installation requirements. The need for types of charging will vary by location and individual preferences. Interviews with practicing electricians and field surveys were performed to assess current capabilities and the need for improvements. Very few current vehicle owners are prepared to make a smooth transition to even level 1 charging. It was determined that the demand for licensed electricians will increase by 25% over 20 years solely for the purpose of charger installation. However, this profession has been dropping over time and is under demand for growth from other areas such as green power.
Technical Paper

Dissecting Robust Resource Partitioning, Robust Time Partitioning, and Robust Partitioning in CAST-32A

2021-11-03
2021-01-5101
CAST-32A strategy for MCP certification builds upon the key terms of robust resource partitioning, robust timing partitioning, and robust partitioning. In this work, we provide technical insight on the interpretation of these terms by building on derivative terms such as resource capacity, capacity allocation, and capacity verification and violation. We discuss on the scope of applicability of these terms from the low-level hardware components up to the complete MCP platform. We also dig into the complexities in implementing robust resource and time partitioning, and show that those concepts must be applied bottom-up from hardware-shared resources up to the whole platform. We also show that, while robust resource partitioning is the preferred choice, it can only be realistically applied to some resources and, in many cases, robust time partitioning is the only choice.
Technical Paper

Seat Belts: A Review of Technological Milestones, Regulatory Advancements, and Anticipated Future Trajectories

2021-10-21
2021-01-5097
Decades after their introduction, seat belts remain the most important safety innovation in automotive history. Seat belt usage remains the single most effective way to minimize the risk of injury or death in severe crash events. Despite having matured, seat belts continue to evolve and improve and are expected to play an equally critical role in future passenger vehicles as increasing automation leads to changes in occupant compartment design and occupant-to-vehicle interaction. In this paper, an overview of major technical milestones in the development of seat belts is presented, ranging from the earliest lap belts to today’s systems that seamlessly synthesize and integrate information from a variety of sensors to prepare the restraints for an imminent crash. A brief overview of contemporary regulatory events is also provided, illustrating how regulatory actions have followed and occasionally driven the development and proliferation of various aspects of occupant restraints.
Technical Paper

The Behavior of Fuel Droplets on a Heated Substrate

2021-10-15
2021-01-5099
The processes of surface wetting and film evaporation play a major role in any application using liquid fuels. Since the behavior of entire multi-liquid films is influenced by many simultaneously occurring physical processes, exact modeling is not yet possible. In order to reduce the complexity and to determine the basic effects in the spreading and evaporation of multi-component films, this study was carried out by placing single 5 μl droplets on a heated metal surface. Various alkanes, ethanol, and mixtures, as well as real gasoline, were studied at surface temperatures between 69°C and 140°C. To describe the processes qualitatively and determine the time-dependent wetted surface area, the droplets were visualized using cameras. With the results, it was possible to determine the course of the wetted surface over time and to compare different liquids under varying surface temperatures.
Technical Paper

Application of Combined Electric Arc Coatings for Parts and Units of Vehicles Recovery in Repair Technologies

2021-10-15
2021-01-5100
This paper is devoted to the methods of increasing wear resistance, corrosion resistance, and service life of parts and assemblies of vehicles during their strengthening and renovation by the use of combined electric arc spraying (EAS) coatings. High density, adhesion, and microhardness of EAS coatings are provided by activation of the spraying process and subsequent nitriding of the sprayed coatings. This study is about the influence of technological parameters of the spraying process—composition, diameter and feed rate of sprayed wires, arc power, spray gas flow rate, spraying distance, speed of spraying spot movement, dispersion of spraying, etc.—on the qualitative characteristics of EAS coatings. The possibility of using pulsed ion nitriding (PIN) to improve the operational characteristics of EAS coatings made of wire materials is considered.
Technical Paper

Designing a Next Generation Trailer Braking System

2021-10-11
2021-01-1268
Passenger vehicles have made astounding technological leaps in recent years. Unfortunately, little of that progress has trickled down to other segments of the transportation industry leaving opportunities for massive gains in safety and performance. In particular, the electric drum brakes on most consumer trailers differ little from those on trailers over 70 years ago. Careful examination of current production passenger vehicle hardware and trailering provided the opportunity to produce a design and test vehicle for a plausible, practical, and performant trailer braking system for the future. This study equips the trailer with high control frequency antilock braking and dynamic torque distribution through use of passenger vehicle grade apply hardware.
Technical Paper

Research on Locked Wheel Protection Function of Aircraft Brake System

2021-10-11
2021-01-1269
Locked wheel protection is an important part of antiskid control for aircraft brake control system. Locked wheel protection compares the wheel speed of two or more wheels, if one of the wheels is too slow, locked wheel protection releases the brake pressure on the slow wheel. This work aims to study the control logic for locked wheel protection. Locked wheel protection control logic consists of 3 key factors: paired wheels, active threshold and inhibit velocity. Focus on comparison different options of these 3 factors, all aspects of control logic for locked wheel protection had been expounded in this study. Simulation and calculation analysis is applied for different locked wheel strategies to evaluate the effect. One conclusion is that the greatest wheel speed of the wheel under control shall be set as a reference speed for locked wheel protection. This study provide the basis to design a proper locked wheel protection function of aircraft brake control system.
Technical Paper

Research on Braking Energy Recovery Strategy of Pure Electric Vehicle

2021-10-11
2021-01-1264
With the increasingly serious global environmental and energy problems, as well as the increasing number of vehicles, pure electric vehicles with its advantages of environmental protection, low noise and renewable energy, become an effective way to alleviate environmental pollution and energy crisis. Due to the current pure electric vehicle power battery technology is not perfect, the range of pure electric vehicle has a great limit. Through the braking energy recovery, the energy can be reused, the energy utilization rate can be improved, and the battery life of pure electric vehicles can be improved. In this paper, a pure electric vehicle is taken as the analysis object, and the whole vehicle analysis model is built. Through the comparative analysis, based on the driver's braking intention and vehicle running state, the braking energy recovery control strategy of double fuzzy control is proposed.
Technical Paper

Decoding Genuine Ceramic Pad Formulations- Materials and Processing

2021-10-11
2021-01-1277
The need to develop genuine ceramic composites for PV applications arose to overcome the challenges associated with traditional semi-metallic pads. The main focus is to achieve better performance, low noise, better pad and rotor wear, and low dust compared to semi- metallic pads. In general, brake pads convert kinetic energy to thermal energy through friction, and operating temperature in semi-metallic brake pads is higher due to the presence of steel having high thermal conductivity. Over the last decade, the customer preference has moved over to ceramic pads due to light coloured pad surface, low rotor and pad wear and low dust compared to semi-metallic pads. The traditional steel has been replaced by Aramid, engineered ceramic fibre, potassium titanate (TISMO D), lapinus fibre (RB 250) to impart similar/better performance. The current work investigates the characterisation of genuine ceramic and semi-metallic composites.
Technical Paper

Potential and Challenges for Application-Specific Friction Characteristics of Race Brake Pads

2021-10-11
2021-01-1282
As a race driver hits the pedal to trigger the braking event, a dynamic load transfer takes place in the car. This is a similar kind of weight transfer experienced on the road while stopping any vehicle abruptly. Modern race cars such as FIA-regulated Grand Touring Car classes GT3 and LMGTE produce a significant aerodynamic downforce at a reasonably high efficiency level. In this type of high downforce race cars, load variations originated by aerodynamics are added onto the mass transfer. The combination of these effects provide a braking effect with this type of cars a highly transient character. At the same time, our customers are facing the challenge of strict technical regulations, usually forbidding brake control systems. In motorsport competition, car performance is of primary priority to help our customers win championships.
Technical Paper

Sensor-controlled Friction Materials based on Liquid Friction Compounds, Chip-in-Pad Concept

2021-10-11
2021-01-1296
In this paper, the concept of integrating thin-film piezo transducers into friction pads by using a liquid friction material compound (LIQFRIC® HP), which is capable of completely embedding the sensor surface and allowing for the force transfer due to a direct contact between sensor and friction material, is explained. The low thickness of the sensor allows for an excellent ratio of sensor volume / friction volume in the pad. The piezo transducer, besides being able to detect positive and negative pressure changes, can also be used via its EMI capability to allow measurements of changes in the shape (and therefore thickness) of the pad during and after testing. Measuring the pressure distribution, the wear and possible defect situations of the pad potentially opens up new means of friction pad- and brake operations or developments.
Technical Paper

Measurement of Particle Dynamics on the Real Vehicle in Different Driving Scenarios with Swarm Sensors

2021-10-11
2021-01-1299
Due to the increase in public attention in the analysis of non-exhaust emission sources because of the growing electrification of vehicles, measurements have been performed in recent years to develop a consistent test standard. In particular, the consideration of tyre and brake abrasion took a predominant position due to the small particle sizes. With measurements under controlled and laboratory-like athmosphere, for example for brakes on dynamometers, attempts have been made to create a uniform test standard according to the Worldwide harmonized Light vehicles Test Procedure (WLTP). However, a transfer to the real driving environment is not yet feasible because of many external disturbance variables, such as the wheel housing or atmospheric variables. Typical reference measurement sensors in the vehicle are only suitable to a limited extent for mobile operation due to their size and the necessary measurement infrastructure.
Technical Paper

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

2021-10-11
2021-01-1262
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.
Technical Paper

Application of Brake System Failed State Performance and Reliability Requirements to Brake System Architecting

2021-10-11
2021-01-1267
The modern braking system in the field today may be controlled by over a million lines of computer code and may feature several hundred moving parts. Although modern brake systems generally deliver performance, even with partial failures present in the system, that is well above regulatory minimums, they also have a level of complexity that extends well beyond what the authors of existing regulations had envisioned. Complexity in the braking system is poised for significant increases as advanced technologies such as self-driving vehicles are introduced, and as multiple systems are linked together to provide vehicle-level “features” to the driver such as deceleration (which can invoke service braking, regenerative braking, use of the parking brake, and engine braking). Rigorous safety-case analysis is critical to bring a new brake system concept to market but may be too tedious and rely on too many assumptions to be useful in the early architecting stages of new vehicle development.
Technical Paper

In-Depth Considerations for Electric Vehicle Braking Systems Operation with Steep Elevation Changes and Trailering

2021-10-11
2021-01-1263
As the automotive industry prepares to roll out an unprecedented range of fully electric propulsion vehicle models over the next few years - it really brings to a head for folks responsible for brakes what used to be the subject of hypothetical musings and are now pivotal questions for system design. How do we really go about designing brakes for electric vehicles, in particular, for the well-known limit condition of descending a steep grade? What is really an “optimal’ design for brakes considering the imperatives for the entire vehicle? What are the real “limit conditions” for usage that drive the fundamental design? Are there really electric charging stations planned for or even already existing in high elevations that can affect regenerative brake capacity on the way down? What should be communicated to drivers (if anything) about driving habits for electric vehicles in routes with significant elevation change?
Technical Paper

Research on High-efficiency Test Method of Vehicle AEB based on High-precision Detection of Radar Turntable Encoder

2021-10-11
2021-01-1273
With the increasingly complex traffic environment, the vehicle AEB system needs to go through a large number of testing processes, in order to drive more safely on the road. For speeding up the development process of AEB and solve the problems of long cycle, high cost and low efficiency in AEB testing, in this paper, a millimeter wave radar turntable is built, and a high-precision detection algorithm of turntable encoder is designed, at the same time, a test method of vehicle AEB based on the detection data of radar turntable encoder is designed. The verification results show that methods described in this paper can be used to develop the vehicle AEB test algorithm efficiently.
Technical Paper

Transfer Film Composition and Characteristics in Copper-Free NAO Brake Pads

2021-10-11
2021-01-1278
Copper-free non-asbestos-organic (NAO) brake pads have been developed to satisfy the copper content regulations in North America. Copper-free NAO brake pads are required to have a stable friction coefficient owing to the electrification of the control systems, as well as to exhibit improved wear resistance to reduce brake dust emissions. Our previous study indicated that the transfer film formed on the rotor surface affects both the friction coefficient stability and amount of wear. In this study, we investigated how different types of inorganic fillers affect the transfer film formation and its composition in a wear test controlled by temperature. It was confirmed that the main component of the transfer film was iron oxide derived from the rotor. Furthermore, the contained components changed according to the appearance of the rotor surface after each wear test.
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