Browse Topic: Braking systems

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HELICOPTER TURBOSHAFT ENGINE IDLE POWER SCHEDULINGAIR4121 (Current)11/26/2025
The purpose of this AIR (Aerospace Information Report) is to provide aircraft and engine designers with a better understanding of helicopter turboshaft engine idle power characteristics and objectives to be considered in the design process. Idle is the lowest steady state power setting. At this setting, the engine typically does not produce enough power to obtain governed output shaft speed (i.e. the shaft speed is determined by the load imposed by the aircraft). In the aircraft, the engine is typically stabilized at this power setting after starting, prior to taxi and for some period of time after rotor shutdown for cool down prior to engine shutoff. Traditionally, the aircraft designer wants idle power scheduled as low as possible and of course, does not want any resulting aircraft operational difficulties such as overcoming the rotor brake. The engine designer, however, desires a higher scheduled power because of the reduced probability of engine operational problems. The attributes of conflicting idle desires are discussed. Other inputs are also considered to establish the engine idle power settings. The information contained herein will assist in the early design phase and ultimately will result in a more optimum match between engine and aircraft requirements.
S-12 Powered Lift Propulsion Committee
Verifying large alternate product code for an Joint Aerospace/Ground Vehicle Document document - JAGV01JAGV00000000000000000000000000001_202511 (Current)11/24/2025
Verifying large alternate product code for an Joint Aerospace/Ground Vehicle Document document - JAGV01
Active Safety Systems Standards Committee
Motor Vehicle Brake FluidJ1703_202511 (Historical)11/21/2025
This SAE Standard covers motor vehicle brake fluids of the nonpetroleum type, based upon glycols, glycolethers, and appropriate inhibitors, for use in the braking system of any motor vehicle such as a passenger car, truck, bus, or trailer. These fluids are not intended for use under arctic conditions. These fluids are designed for use in braking systems fitted with rubber cups and seals made from styrene-butadiene rubber (SBR), or a terpolymer of ethylene, propylene, and a diene (EPDM).
Brake Fluids Standards Committee
Hot Impulse Test for Hydraulic Brake Hose AssembliesJ1833_202510 (Current)10/13/2025
test
Automotive Brake and Steering Hose Standards Comm
Quantitative Analysis of a Hybrid Electric HMMWV for Fuel Economy Improvement2024-01-33564/23/2025
ABSTRACT This paper presents a quantitative analysis and comparison of fuel economy and performance of a series hybrid electric HMMWV (High Mobility Multi-purpose Wheeled Vehicle) military vehicle with a conventional HMMWV of equivalent size. Hybrid vehicle powertrains show improved fuel economy gains due to optimized engine operation and regenerative braking. In this paper, a methodology is presented by which the fuel economy gains due to optimized engine are isolated from the fuel economy gains due to regenerative braking. Validated vehicle models as well as data collected on test tracks are used in the quantitative analysis. The regenerative braking of the hybrid HMMWV is analyzed in terms of efficiency from the kinetic energy at the wheels to the portion of regenerative power which is retrievable by the battery. The engine operation of both the series hybrid and conventional HMMWV are analyzed using a 2-D bin analysis methodology. Finally, the vehicle model is used to make recommendations on improving the fuel economy of the series hybrid as well as the conventional HMMWV.
Nedungadi, Ashok, Masrur, Abul, Khalil, Gus
Test JSW2-6715 NewJSW26715_202501 (Current)1/17/2025
testing
Ground Vehicle European Prospect Committee
400Hz High Speed Static Transfer Switch2008-01-287711/11/2024
The objective of this project was to replace electromechanical power line contactors with a Static Transfer Switch (STS) to improve the transfer of electrical power between aircraft generators and decrease required maintenance. The switch requirements include high reliability, lightweight, and high speed (less than 15mS) power transfer. An STS can shorten the bus transfer time to less than the “ride-through” of aircraft electronic loads and therefore have the ability to control and transfer electrical power while maintaining critical mission requirements. The content of this paper and presentation will discuss the initial problem, the research and development approach, design, and initial testing of the STS.
Cooper, Ronald C., Cooper, Evan C.
Friction Performance Analysis of Mine Wet Multi-Disc Brake02-17-01-000110/28/2023
Abstract This article takes the wet multi-disc brake used in mining Isuzu 600P as the research object, establishes a simplified three-dimensional model of its key components through SOLIDWORKS and imports it into ANSYS Workbench to establish the flow field and structure field model of the wet brake. Based on the fluid–solid coupling, the finite element simulation of the temperature field and stress field of the friction pair of the wet brake under different braking pressures, braking initial speeds, and fluid viscosities was carried out, and then the position changes of the friction pairs at high temperature hot spots and high stress points were analyzed to determine the stability of its friction performance. Finally, by comparing the temperature change curves of the same point during the braking process under different braking conditions, the validity of the finite element analysis results is verified. The results show that the flow field pressure inside the wet brake is opposite to the flow field velocity, the initial braking velocity is the most influential factor on the friction performance of the friction pair, affected by the fluid, the maximum equivalent stress of the groove between the core plates is the same as the braking force. Pressure, braking initial speed, and fluid viscosity are proportional.
Zhang, Chuanwei, Jin, Xiaohe, Zhao, Dawei, Liu, Jinpeng
Recurrent Neural Network Model for On-Board Estimation of the Side-Slip Angle in a Four-Wheel Drive and Steering Vehicle15-17-01-00039/23/2023
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 adaptability to different road conditions and tire wear levels has been verified through a sensitivity analysis and model testing on real-world data proves the robustness and accuracy of the proposed solution achieving a root mean square error (RMSE) of 0.18 deg and a maximum absolute error of 1.52 deg on the test dataset. The proposed model can be considered as a reliable and cheap potential solution for the real-time on-board side-slip angle estimation in serial cars.
Giuliacci, Tiziano Alberto, Ballesio, Stefano, Fainello, Marco, Mair, Ulrich, King, Julian
Increasing Agility through AMESim to Iteratively Simulate, Analyze and Design Helicopter Brake SystemsF-0079-2023-180025/16/2023
Debacher, Kevin, Spiller, Kaila
A Novel Approach for the Frequency Shift of a Single Component Eigenmode through Mass Addition in the Context of Brake Squeal Reduction15-16-01-00049/23/2022
Abstract Brake squeal reduces comfort for the vehicle occupants, damages the reputation of the respective manufacturer, and can lead to financial losses due to cost-intensive repair measures. Mode coupling is mainly held responsible for brake squeal today. Two adjacent eigenfrequencies converge and coalesce due to a changing bifurcation parameter. Several approaches have been developed to suppress brake squeal through structural changes. The main objective is to increase the distance of coupling eigenfrequencies. This work proposes a novel approach to structural modifications and sizing optimization aiming for a start at shifting a single component eigenfrequency. Locations suitable for structural changes are derived such that surrounding modes do not significantly change under the modifications. The positions of modifications are determined through a novel sensitivity calculation of the eigenmode to be shifted in frequency. In the present work, the structural changes are carried out on a beam and a brake caliper. Selected eigenfrequencies are shifted while the frequencies of the other eigenmodes are simultaneously fixed. Experimental investigations for the brake caliper validate the numerical findings and the applicability as well as efficiency of the proposed methods.
Deutzer, Marcel, Stender, Merten, Tüpker, Nicolas, Hoffmann, Norbert
V4-002 FK testSAE-PP-009554/26/2022
Heavy vehicles are essential for the modern economy, delivering critical food, supplies, and freight throughout the world. Connected heavy vehicles are also driven by embedded computers that utilize internal communication using common standards. However, some implementations of the standards leave an opening for a malicious actor to abuse the system. One such abuse case is a cyber-attack known as the “Address Claim Attack.” Proposed in 2018, this attack uses a single network message to disable all communication to and from a target electronic control unit, which may have a detrimental effect on operating the vehicle. This article demonstrates the viability of the attack and then describes the implementation of a solution to prevent this attack in real time without requiring any intervention from the manufacturer of the target devices. The defense technique uses a bit-banged Controller Area Network (CAN) filter to detect the attack. Once an attack is discovered, the defender induces a CAN protocol error to remove the malicious message from the network. We discuss our results in terms of their applicability for Address Claim Attacks and possible implications for preventing a variety of network-based attacks in real time.
Mutagaana, Festo
External Automatic Slack Adjuster Performance RequirementsJ1513_202111 (Current)11/3/2021
The performance requirements have been established for external automatic slack adjusters when tested to SAE J1462.
Truck and Bus Foundation Brake Committee
Driveline Parking Brake Test Procedure for Medium Duty VehiclesJ2690_202110 (Current)10/28/2021
This SAE Recommended Practice establishes uniform test procedures for friction based parking brake components used in conjunction with hydraulic service braked vehicles with a gross vehicle weight rating greater than 4500 kg (10 000 lb). The components covered in this document are the primary actuation and the foundation park brake. Various peripheral devices such as application dashboard switches or indicators are not included. These test procedures include the following: a Brake Related Tests 1 Brake Functional Performance 2 Brake Dynamic Torque Performance 3 Brake Corrosion Resistance 4 Brake Endurance with Torque 5 Brake Endurance without Torque 6 Vibration Resistance 7 Brake Ultimate Static Load 8 Brake Lining Wear Adjuster Function b Actuation Related Tests 1 Mechanical Actuator Functional Performance 2 Mechanical Actuator Endurance 3 Mechanical Actuator Quick Release 4 Mechanical Actuator Ultimate Load 5 Spring Apply Actuator Functional Performance 6 Spring Apply Actuator Operating Temperature Range 7 Spring Apply Actuator Endurance 8 Spring Apply Actuator Corrosion Resistance 9 Spring Apply Actuator On-Off Switch 10 Spring Apply Actuator Vibration
Truck and Bus Hydraulic Brake Committee
Brake Lining Quality Test ProcedureJ661_202110 (Current)10/26/2021
The purpose of this SAE Recommended Practice is to establish a uniform laboratory procedure for securing and reporting the friction and wear characteristics of brake linings. The performance data obtained can be used for in-plant quality control by brake lining manufacturers and for the quality assessment of incoming shipments by the purchasers of brake linings.
Brake Linings Standards Committee
Service Maintenance of SAE J1703 and SAE J1704 Brake Fluids in Motor Vehicle Brake SystemsJ1707_202106 (Current)6/10/2021
This SAE Recommended Practice provides basic recommendations for dispensing and handling of SAE J1703 and SAE J1704 Brake Fluids by Service Maintenance Personnel to assure their safe and effective performance when installed in or added to motor vehicle hydraulic brake actuating systems. This document is concerned only with brake fluid and those system parts in contact with it. It describes general maintenance procedures that constitute good practice and that should be employed to help assure a properly functioning brake system. Recommendations that promote safety are emphasized. Specific step-by-step service instructions for brake maintenance on individual makes or models are neither intended nor implied. For these, one should consult the vehicle manufacturer’s service brake maintenance procedures for the particular vehicle. Vehicle manufacturer’s recommendations should always be followed.
Brake Fluids Standards Committee
Automotive Air Brake Line Couplers (Gladhands)J318_202106 (Current)6/10/2021
This SAE Recommended Practice is intended to provide design, interchangeable dimensions, testing procedures, performance requirements, and minimum identification for gladhand-type air line couplers used to connect the brake systems of trucks, truck-tractors, trailers, and dollies when these vehicles are joined to operate as a combination unit.
Truck and Bus Brake Supply and Control Components Committee
Low Water Tolerant Brake FluidsJ1705_202105 (Current)5/28/2021
This SAE Recommended Practice was prepared to provide engineers, designers, and manufacturers of motor vehicles with a set of minimum performance requirements in order to assess the suitability of silicone and other low water tolerant type brake fluids (LWTFs) for use in motor vehicle brake systems. These fluids are designed for use in braking systems fitted with rubber cups and seals made from styrene-butadiene rubber (SBR), or a terpolymer of ethylene, propylene, and a diene (EPDM). In the development of the recommended requirements and test procedures contained herein, it is concluded that the LWTFs must be functionally compatible with braking systems designed for SAE J1703 and SAE J1704 fluids. To utilize LWTFs to the fullest advantage, they should not be mixed with other brake fluids. Inadvertent mixtures of LWTFs with fluids meeting SAE J1703 are not known to have any adverse effects on performance, but not all combinations have been tested. Vehicle manufacturer’s recommendations should be followed where indicated. These fluids are not necessarily suitable for use in central hydraulic or pumped systems and are not intended for use below temperatures of -50 °C (-58 °F). Brake fluids covered under this document are not required to tolerate water and extreme caution should be exercised to prevent accidental entry of water which might lead to brake failure. Other performance characteristics of these LWTFs not covered in this document are discussed in Appendix A.
Brake Fluids Standards Committee
SAE J1698-1A Pedestrian Protection EDR Output Data Definition, Appendix to SAE J1698-1 Event Data Recorder - Output Data DefinitionJ1698/1A_202104 (Current)4/30/2021
SAE J1698-1A creates an appendix to SAE J1698-1. The appendix contains EDR Record parameters and definitions related to light duty passenger vehicle pedestrian protection systems.
Event Data Recorder Committee
Disc Wheel and Hub or Drum Interface Dimensions - Truck and BusJ694_202104 (Current)4/30/2021
This SAE Recommended Practice contains dimensions and their tolerances concerning disc wheel to hub or drum interface areas for truck and bus applications. Disc wheels designed only for single wheel applications (not dual wheels) for light trucks and special or less common applications are not covered in this document.
Truck and Bus Wheel Committee
Test Procedures for Non-SAE Hydraulic HosesJ2545_202104 (Current)4/14/2021
This SAE Recommended Practice identifies test procedures and parameters which may be used to evaluate, qualify and inspect non-SAE hydraulic hoses or other hose constructions which do not conform to any established ISO or national standards defining hydraulic hoses. (Non-SAE hydraulic hoses are defined as those which do not conform to the categories listed in SAE J517.) It is not intended for evaluating fluoropolymer lined hose constructions or hose constructions with working pressures above 86 MPa.
Hydraulic Hose and Hose Fittings Committee
Speed Planning System for Commercial Vehicles in Mountainous Areas2021-01-01264/6/2021
There are a large number of curves and slopes in the mountainous areas. Unreasonable acceleration and deceleration in these areas will increase the burden of the brake system and the fuel consumption of the vehicle. The main purpose of this paper is to introduce a speed planning and promotion system for commercial vehicles in mountainous areas. The wind, slope, curve, engine brake, and rolling resistances are analyzed to establish the thermal model of the brake system. Based on the thermal model, the safe speed of the brake system is acquired. The maximum safe speed on the turning section is generated by the vehicle dynamic model. And the economic speed is calculated according to the fuel consumption model. The planning speed is provided based on these models. This system can guide the driver to handle the vehicle speed more reasonably. According to the simulation, compared to cruise control, speed planning can save fuel consumption at a mean value of 9.13% in typical mountainous areas. The field test of a typical commercial vehicle shows that this system can increase fuel efficiency by 4.26% compared to an experienced driver during a journey in a mountainous area.
Peng, Dengzhi, Fang, Kekui, Tian, Zhongpeng, Zhang, Yuxiao, Tan, Gangfeng
Accurate Pressure Control Based on Driver Braking Intention Identification for a Novel Integrated Braking System2021-01-01004/6/2021
With the development of intelligent and electric vehicles, higher requirements are put forward for the active braking and regenerative braking ability of the braking system. The traditional braking system equipped with vacuum booster has difficulty meeting the demand, therefore it has gradually been replaced by the integrated braking system. In this paper, a novel Integrated Braking System (IBS) is presented, which mainly contains a pedal feel simulator, a permanent magnet synchronous motor (PMSM), a series of transmission mechanisms, and the hydraulic control unit. As an integrative system of mechanics-electronics-hydraulics, the IBS has complex nonlinear characteristics, which challenge the accurate pressure control. Furthermore, it is a completely decoupled braking system, the pedal force doesn’t participate in pressure-building, so it is necessary to precisely identify driver’s braking intention. To improve the control accuracy of the system, this paper proposed a novel pressure control strategy based on driver braking intention identification. Firstly, the structure and working principle of the novel integrated braking system was introduced. Secondly, the driver's braking intention identification strategy was designed. Thirdly, Considering the nonlinear and dynamic characteristics of the system, a cascade closed-loop control strategy including a pressure loop by the feedforward-feedback method, a position loop by the sliding-mode control method, and current loop with friction compensation was proposed. Finally, based on dSPACE products, a hardware-in-the-loop (HiL) experimental bench was built for algorithm verification. The HiL experiment results show that the pressure control strategy has the advantages of accurate response, the braking system pressure follows the driver's expected pressure well.
Zhu, Bing, Zhang, Yihan, Zhao, Jian, Chen, Zhicheng, Jin, Wanli
Snowmobile Service Brake SystemJ44_202103 (Current)3/16/2021
This SAE Standard establishes a uniform testing procedure and performance requirements for the level surface testing of hand-operated service brake systems on snowmobiles.
Snowmobile Technical Committee
Brake System Test Procedure - SnowmobilesJ45_202103 (Current)3/8/2021
This SAE Recommended Practice establishes a uniform procedure for the level surface testing of hand-operated brake systems on recreational noncompetitive snowmobiles.
Snowmobile Technical Committee
Graphic Symbols for Aircraft Hydraulic and Pneumatic SystemsAS1290C (Current)2/12/2021
This SAE Aerospace Standard (AS) provides a system of graphic symbols and line codings that are intended primarily for usage in hydraulic and pneumatic system schematic diagrams for all types of aircraft.
A-6 Aerospace Actuation, Control and Fluid Power Systems
Thread SealantsJ1615_202101 (Current)1/27/2021
Male pipe threads, including male dryseal pipe threads, when made into assemblies or installed into ports, will generally leak if not covered with a sealant. This SAE Recommended Practice is intended as a guide to assist designers and/or users in the selection and application of various types of thread sealants. The designers and users must make a systematic review of each type and application and then select the sealant to fulfill the requirements of the application. The following are general guidelines and are not necessarily a complete list.
Air Brake Tubing and Tube Ftg Committee
Validation of Compressibility Test Systems for Friction MaterialsJ3079/1_202101 (Current)1/13/2021
This SAE Recommended Practice (RP) applies to the validation process for test systems used to measure deflection (compressibility, creep, or swell and growth) of friction materials and friction material assemblies. The materials or assemblies can fit passenger cars, light trucks, and commercial vehicles equipped with hydraulic or air brake systems, using disc or drum brakes.
Brake Linings Standards Committee
Dimensional Compatibility for Commercial Vehicles Fitment of Complete Wheels in Drum Brake Applications - Truck and BusJ1865_202011 (Current)11/4/2020
This SAE Recommended Practice defines a clearance line for establishing dimensional compatibility between drum brakes and wheels with 19.5 inch, 22.5 inch, and 24.5 inch diameter rims. Wheels designed for use with drum brakes may not be suitable for disc brake applications. The lines provided establish the maximum envelope for brakes, including all clearances, and minimum envelope for complete wheels to allow for interchangeability. This document addresses the dimensional characteristics only, and makes no reference to the performance, operational dynamic deflections, or heat dissipation of the system. Valve clearances have not been included in the fitment lines. Bent valves may be required to clear brake drums. Disc brake applications may require additional running clearances beyond those provided by the minimum contour lines. Mounting systems as noted are referenced in SAE J694.
Truck and Bus Wheel Committee
Air Brake Performance and Wear Test Code Commercial Vehicle Inertia DynamometerJ2115_202008 (Current)8/20/2020
This SAE Standard provides test procedures for air and air-over-hydraulic disc or drum brakes used for on-highway commercial vehicles over 4536 kg (10000 pounds) GVWR. This recommended practice includes the pass/fail criteria of Federal Motor Vehicle Safety Standard No. TP-121D-01.
Truck and Bus Foundation Brake Committee
Truck and Bus Grade Parking Performance Test ProcedureJ360_202008 (Historical)8/19/2020
This SAE Recommended Practice establishes methods to determine grade parking performance with respect to: a. Ability of the parking brake system to lock the braked wheels. b. The vehicle holding or sliding on the grade, fully loaded or unloaded. c. Applied manual effort. d. Unburnished or burnished brake lining friction conditions. e. Down and up grade directions.
Truck and Bus Brake Systems Committee
Applying Automotive EDR Data to Traffic Crash Reconstruction Virtual Pre-Conference CertificationC20168/7/2020
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 manufacturer. The class presents the generic analysis step by step, then groups EDRs into manufacturer-specific families and their data limitations, and works case studies that highlight targeted key learning objectives. The student will also learn key points to satisfy court Frye and Daubert requirements for EDR data to be admissible, and suggest methods to present EDR data that will communicate the data understandably to attorneys and lay juries. This course has been approved by the Accreditation Commission for Traffic Accident Reconstruction (ACTAR) for 20 Continuing Education Units (CEUs). Upon completion of this seminar, accredited reconstructionists should mail a copy of their course certificate and the $5 student CEU fee to ACTAR, PO Box 1493, North Platte, NE 69103. By attending this seminar, you will be able to: Describe EDR sensor operation, recording interval and duration, resolution, accuracy, and time latency and articulate the limitations of applying the data to crash analysis Calculate min and max speeds prior to loss of control or braking, and at impact based on the last accurate EDR pre-crash speed data point Evaluate EDR vs. actual ground speed for specific vehicle operational conditions and vehicle equipment modifications Calculate speed at impact and closing speeds by combining EDR Delta V data with normally collected scene and vehicle data such as post crash travel distance, departure angle, drag factor, and vehicle weights Apply data to inline rear end, head on, and angular collisions Reconcile EDR data with other physical evidence and combine to narrow speed ranges Use time-distance and overlay EDR data on scene maps/diagrams to show where critical driving inputs were made vs. inputs required to avoid collisions CEUs
Measurement of Copper and Other Elements in Brake Friction MaterialsJ2975_202007 (Current)7/23/2020
This procedure describes a method for generating, preparing and analyzing samples of new and unused brake friction materials for their chemical constituents.
Brake Linings Standards Committee
Parking Brake Control Identification - Vehicles with Hydraulic Brake Systems and Automatic TransmissionsJ2688_202007 (Current)7/13/2020
The scope and purpose of the SAE Recommended Practice is to provide standards for the control and indication of parking brakes in hydraulic braked vehicles over 4540 kg (10000 lb) GVWR. This recommended practice pertains to automatic transmission applications and supplements the SAE J915 recommended practice. This recommended practice does not address parking brake system performance. Parking brake system performance, both static and dynamic conditions, is the responsibility of the OEM vehicle manufacturer or manufacturers that modify the vehicle by adding special vocational required equipment (such as but not limited to outriggers, cranes, etc.).
Truck and Bus Hydraulic Brake Committee
Articulated Vehicle Lateral Stability Management via Active Rear-Wheel Steering of Tractor Using Fuzzy Logic and Model Predictive Control02-13-02-00087/1/2020
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 the semitrailer’s rear wheels have little effect on the tractor’s directional control. In this study, viability of active rear-wheel steering of tractor to maintain the stability of an articulated vehicle during a high-speed obstacle avoidance maneuver is investigated. Two different controllers, fuzzy logic and linear model-based predictive controllers, are proposed to minimize the off-tracking behavior of an articulated vehicle. The controllers were tested in IPG/TruckMaker environment with MATLAB/Simulink interface on roads with various coefficient of adhesions, performing single lane change maneuvers. The simulated results showed that jackknifing occurring right after sudden lane changes can be successfully prevented using the tractor’s active rear-wheel steering based on model predictive control algorithm when the feedback gains are tuned correctly.
Sahin, Hasan, Akalin, Ozgen
Dimension Compatibility for Commercial Vehicle Wheels to Air Disc Brake Calipers - Truck and BusJ2803_202006 (Current)6/5/2020
This SAE Recommended Practice defines the boundary line for establishing dimensional compatibility between air disc brake calipers and 22.5 x 8.25 inch disc wheels, including bent valve stems on steel wheels and manufacturer recommended valve stems on aluminum wheels. The line establishes the minimum wheel with valve stem envelope to allow interchangeability. The line does not accommodate customer-specific wheels (such as OEM-specific stylized wheels) or customer-specific brakes. This document addresses dimensional characteristics only and makes no reference to the performance, operational dynamic deflections or heat dissipation of the system. It is up to the system integrator to ensure sufficient clearance exists between the caliper, wheel and valve stem to provide safe operating conditions. Mounting systems as noted are referenced in SAE J694.
Truck and Bus Wheel Committee
Air Reservoir Capacity Performance Guide—Trucks and BusesJ1609_202006 (Historical)6/5/2020
This SAE Recommended Practice establishes performance guidelines of the air reservoir systems used on trucks, towing trucks, truck-tractors, trailers, and converter dollies with GVWRs over 10 000 lb designed to be used on the highway. NOTE: Compliance with this document does not guarantee compliance with the air reservoir requirements of FMVSS 121.
Truck and Bus Brake Supply and Control Components Committee
Low-Duty Inertia Dynamometer Hydraulic Brake Wear Test Procedures for Vehicles Above 4536 kg (10000 pounds) of GVWRJ3006_202005 (Current)5/26/2020
This Recommended Practice is derived from OEM and tier-1 laboratory tests and applies to two-axle multipurpose passenger vehicles, or trucks with a GVWR above 4536 kg (10 000 pounds) equipped with hydraulic disc or drum service brakes. Before conducting testing for a specific brake sizes or under specific test conditions, review, agree upon, and document with the test requestor any deviations from the test procedure. Also, the applicable criteria for the final test results and wear rates deemed as significantly different require definition, assessment, and proper documentation; especially as this will determine whether or not Method B testing is needed. This Recommended Practice does not evaluate or quantify other brake system characteristics such as performance, noise, judder, ABS performance, or braking under extreme temperatures or speeds. Minimum performance requirements are not part of this recommended practice. Consistency and margin of pass/fail of the minimum requirements related to wear rates and wear behavior can be assessed as part of the project in coordination with the test requestor. NOTE: This Recommended Practice uses the unit conversion and rounding techniques from the NIST Special Publication 811. This to ensure the use of standard conversion factors and to determine the appropriate number of significant digits to ensure the Rounding Error (RE) of the converted unit is smaller than or similar to the RE of the original English or Imperial unit.
Truck and Bus Hydraulic Brake Committee
Integrated Regenerative Braking System and Anti-Lock Braking System for Hybrid Electric Vehicles & Battery Electric Vehicles2020-01-08464/14/2020
This paper describes development of an integrated regenerative braking system and anti-lock brake system (ABS) control during an ABS event for hybrid and electric vehicles with drivelines containing a single electric motor connected to the axle shaft through an open differential. The control objectives are to recuperate the maximum amount of kinetic energy during an ABS event, and to provide no degraded anti-lock control behavior as seen in vehicles with regenerative braking disabled. The paper first presents a detailed control system analysis to reveal the inherent property of non-zero regenerative braking torque control during ABS event and explain the reason why regenerative braking torque can increase the wheel slip during ABS event with existing regenerative braking control strategies. Then, the regenerative brake control problem during ABS events is formulated with a unified control system architecture where the regenerative braking torque is coordinated with the friction braking torque of ABS system. An integrated closed loop based wheel slip control including both regenerative braking control loop and friction braking control loop during ABS event, referred to as RBS-ABS event control, is developed. The maximum regenerative braking is achieved and optimal vehicle braking performances and vehicle stability are maintained during ABS event. Finally, simulation tests are provided to illustrate RBS-ABS event control as an effective solution to satisfy desired wheel slip with the same level of stop distance in comparison with that of ABS control only while performing energy recuperation.
Yao, Yixin, Zhao, Yanan, Yamazaki, Mark
Modeling, Validation and Control Strategy Development of a Hybrid Super Sport Car Based on Lithium Ion Capacitors2020-01-04424/14/2020
Today, the contribution of the transportation sector on greenhouse gases is evident. The fast consumption of fossil fuels and its impact on the environment have given a strong impetus to the development of vehicles with better fuel economy. Hybrid electric vehicles fit into this context with different targets, starting from the reduction of emissions and fuel consumption, but also for performance and comfort enhancement. Lamborghini has recently invested in the development of a hybrid super sport car, due to performance and comfort reasons. Aventador series gearbox is an Independent Shift Rod gearbox with a single clutch and during gear shifts, as all the single clutch gearbox do, it generates a torque gap. To avoid the additional weight of a Dual Clutch Transmission, a 48V Electric Motor has been connected to the wheels, in a P3 configuration, to fill the torque gap, and to habilitate regenerative braking and electric boost functions. This paper discusses the usage of a control-oriented vehicle and powertrain model to analyze the performance of the first Lithium Ion Capacitor-based hybrid V12 by Automobili Lamborghini. The internal combustion engine, the gearbox, the LiC and the vehicle longitudinal dynamics models have been initially validated through the comparison with experimental data from chassis dynamometer testing, in addition to experimental results from specific components’ testing. As shown in the paper, the validated model has then been used to develop control strategies aimed at increasing comfort and performance, but also to expand the hybrid system capabilities by widening the LiC working range, and to study the possibility of implementing CO2 reduction-oriented control functions.
Franceschi, Alessandro, Cavina, Nicolo, Parenti, Riccardo, Reggiani, Maurizio, Corti, Enrico
Research on Compensation Redundancy Control for Basic Force Boosting Failure of Electro-Booster Brake System2020-01-02164/14/2020
As a new brake-by-wire solution, the electro-booster (Ebooster) brake system can work with the electronic stability program (ESP) equipped in the real vehicle to realize various excellent functions such as basic force boosting (BFB), active braking and energy recovery, which is promoting the development of smart vehicles. Among them, the BFB is the function of Ebooster's servo force to assist the driver's brake pedal force establishing high-intensity braking pressure. After the BFB function failure of the Ebooster, it was not possible to provide sufficient brake pressure for the driver's normal braking, and eventually led to traffic accidents. In this paper, a compensation redundancy control strategy based on ESP is proposed for the BFB failure of the self-designed Ebooster. Firstly, introduced the working principle of Ebooster and ESP, and a suitable pressure-building circuit was selected for the dual brake actuator system; Secondly, after the BFB failure of Ebooster, the rule-based strategy of braking awareness recognition was designed. Thirdly, a layered closed-loop compensation control strategy is designed based on the ESP to restore the pressure building capacity of the hydraulic system. Finally, based on dSPACE products, a hardware-in-the-loop (HiL) experimental bench with dual brake actuators including ESP and Ebooster was built for algorithm verification. The HiL experiment results show that after the BFB failure of Ebooster, the designed compensation redundancy control algorithm can restore the Pressure-Volume (P-V) characteristics of the brake system just like Ebooster's conventional BFB mode, and improve vehicle driving safety.
Zhao, Jian, Chen, Zhicheng, Zhu, Bing, Wu, Jian
Series Fuzzy PID with Anti-windup Controller for Intelligent Vehicle2020-01-01134/14/2020
A series fuzzy PID controller with anti-windup scope (SFPCA) is proposed in this paper to address saturation nonlinear problem and control disturbance caused by uncertainty of actuator model. In order to achieve novel dynamic and steady-state performance, the fuzzy controller and PID controller are fused into series, which realizes excellent dynamic performance of fast response and low overshoot like pure fuzzy controller at the initial response stage, and the excellent steady-state performance of stable and no static difference like PID control at the later response stage. The Hurwitz low is employed to configure PID parameters and 49 rules are designed for fuzzy controller. Since the input of the actuator could not be infinite, the actuator being saturated for a long time could reduce the stability of system and, even lead to irreversible damage. Moreover, after exiting the saturation state, it is difficult to quickly recover to the fast and stable response state of the original system. Therefore, an anti-windup scope is meticulously developed to limit the system input to a reasonable range under the saturation state, and, in the unsaturated state, the original Fuzzy PID control is restored. In order to verify the performance of the algorithm, four comparison algorithms were adopted, including pure PD, pure PID, pure Fuzzy and series Fuzzy PID controller (SFPC), and two typical commands like step and sine are employed as desired signals. The experimental results show that the SFPCA has more excellent dynamic and steady performance than pure PD, pure PID, pure Fuzzy and series Fuzzy PID controller (SFPC).
Luo, Chao
Model-Based Brake Disc Temperature Prediction on High Speed Testing Mode and Circuit2020-01-02144/14/2020
A brake is a mechanical device that inhibits the motion by absorbing energy from a moving system. It is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by friction energy. Commonly, most brakes use friction between two surfaces pressed together to convert the kinetic energy of the moving object into heat, though other methods of energy conversion may be employed. If braking is repeated or sustained in high load or high-speed conditions, the motion will be unstable and can lead to a loss of stopping power because the disc capability for braking is not enough. These phenomena are generally defined as brake fading. Brake fade is caused by an overheating brake system. This paper describes the thermal modeling and process to predict the disk temperature under a condition which causes the fade characteristics. Also, the model of disc temperature prediction developed with consideration of acceleration and deceleration from the vehicle specification by combining the full vehicle modeling with thermal disc model. The disc temperature model is a highly reliable model because it is correlated with measurement data and based on this correlated thermal model, it can be predicted the brake disc geometrical parameters according to the specification change of the vehicles in the concept stage before the prototype development.
Jeong, PilYoung, Lee, Jaekil, Oswald, Mario, Kellner, Stefan
Simulation of Curved Road Collision Prevention Warning System of Automobile Based on V2X2020-01-07074/14/2020
The high popularity of automobiles has led to frequent collisions. According to the latest statistics of the United Nations, about 1.25 million people worldwide die from road traffic accidents each year. In order to improve the safety of vehicles in driving, the active safety system has become a research hotspot of various car companies and research institutions around the world. Among them, the more mature and popular active security system are Forward Collision Warning(FCW) and Autonomous Emergency Braking(AEB). However, the current active safety system is based on traditional sensors such as radar and camera. Therefore, the system itself has many limitations due to the shortage of traditional sensors. Compared to traditional sensors, Vehicle to Everything (V2X) technology has the advantages of richer vehicle parameter information, no perceived blind spots, dynamic prediction of dangerous vehicle status, and no occlusion restriction. In order to overcome the many shortcomings of the existing anti-collision warning system and strategy, this paper proposes a curved road collision prevention warning strategy based on V2X technology. Through V2X technology, the state information released by the neighboring car and the road environment information issued by the roadside unit are obtained. Using the above information and the state information of the vehicle, the relative positional relationship between the car and the neighboring car is dynamically predicted in real time, and then a two-degree-of-freedom dynamic collision time model and a two-degree-of-freedom collision time threshold model are proposed and designed. Finally, based on the output parameters of the above model, a two-degree-of-freedom curved road collision prevention warning system of automobile based on V2X technology is proposed, and a layered early warning mechanism is established. Through the PreScan environment, the typical working conditions and early warning strategy models are built by Matlab & Simulink, and the simulation of the early warning strategy is completed.
Li, Xuanhe, Wu, Jian, He, Rui, Zhu, Bing, Zhao, Jian, Zhou, Hang
Effect of Stator Surface Area on Braking Torque and Wall Heat Dissipation of Magnetorheological Fluid Retarder2020-01-09374/14/2020
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 dissipation rate of retarder and improve the stability of the retarder's braking torque. In order to study the effect of stator radius on braking torque of MRF retarder under an external magnetic field, a braking torque model was established based on MRF with Bingham model properties, and a heat transfer model of wall phase change material was established to analyze the relationship between heat transfer and braking torque of MRF retarder. The results show that the braking torque of the MRF retarder increases rapidly with the increase of the radius outside the effective working area of MRF, which increases faster at high speed and increases the stator wall surface heat dissipation, but the rate of heat dissipation increases relatively slowly. The wall surface with a heat pipe can take away the heat generated by the retarder and cool the retarder. Under the appropriate stator surface conditions, phase change materials are used on the wall surface of the retarder to dissipate heat, which improves the stability of the braking torque of the retarder and promotes the development of MRF retarder to high power.
Liu, ZhiQiang, Tan, Gangfeng, Tian, Zhongpeng, Zhou, Mi, Agyeman, Philip, Frimpong, Justice
A Pre-Warning Method for Cornering Speed of Concrete Mixer Truck2020-01-10034/14/2020
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 Newton Leibniz numerical calculation method, Matlab is used to obtain the mathematical model of the centroid position and the main parameters of the stirring tank. Then the model is verified by the neural network algorithm. Finally, according to the dynamic position and lateral acceleration of the vehicle’s centroid, the dynamic simulation is carried out by TruckSim to obtain the theoretical speed threshold. The pre-warning system can warn the driver according to the comparison of real-time speed and calculated velocity threshold. In this paper, a 7.8 m3 concrete mixer truck is selected for simulation experiments. The results show that the lateral offset of the centroid is up to 206.4 mm and the maximum lateral force is 682N under normal working conditions, and the safe turning speed of the vehicle is reduced by at least 4.71% due to the centroid change. The pre-warning method proposed in this paper can improve the safety of cornering traffic effectively, and can be utilized in the further intelligent transportation system.
Jiang, Yifeng, Tan, Gangfeng, Wang, Haoyu, Wang, Zelong, Wang, Zhenyu, Li, Ming
Pressure Tracking Control of Electro-Mechanical Brake Booster System2020-01-02114/14/2020
The Electro-Mechanical Brake Booster system (EMBB) is a kind of novel braking booster system, which integrates active braking, regenerative braking, and other functions. It usually composes of a servo motor and the transmission mechanism. EMBB can greatly meet the development needs of vehicle intelligentization and electrification. During active braking, EMBB is required to respond quickly to the braking request and track the target pressure accurately. However, due to the highly nonlinearity of the hydraulic system and EMBB, traditional control algorithms especially for PID algorithm do not work well for pressure control. And a large amount of calibration work is required when applying PID algorithms to pressure control in engineering. In this paper, a fuzzy adaptive PI pressure control algorithm based on feed-forward is proposed to a novel self-designed EMBB mechanism, which is utilized to overcome the nonlinear pressure control problem when EMBB is in active braking and improve the control effect of PID algorithm. First, the structure of the EMBB system used in the paper and its working principle is presented. Second, this paper designs a two-layer control algorithm to implement the pressure control of EMBB. The upper layer is a pressure control loop using fuzzy PI algorithm based on feedforward, and the lower layer is a motor control loop composed of position loop and current loop. Finally, to verify the proposed control algorithm, a series of pressure tracking tests were performed under multiple operating conditions based on a real vehicle platform equipped with EMBB. The experimental results show that the proposed control algorithm can effectively enhance the accuracy of EMBB pressure control and its response speed during active braking compared with PID algorithm. Therefore, the proposed algorithm can effectively improve the effect of EMBB pressure control.
Yang, Weihong, Wu, Jian, He, Rui, Zhu, Bing, Zhao, Jian, Chen, Zhicheng
Brake Power Availability Led Optimisation of P0 versus P2 48V Hybrid Powertrain Architectures2020-01-04394/14/2020
Through improving the 48V hybrid vehicle archetype, governmental emission targets could be more easily met without incurring the high costs associated with increasing levels of electrification. The braking energy recovery function of hybrid vehicles is recognised as an effective solution to reduce emissions and fuel consumption in the short to medium term. The aim of this study was to evaluate methods to maximise the braking energy recovery capability of the 48V hybrid electric vehicle over pre-selected drive cycles using appropriately sized electrified components. The strategy adopted was based upon optimising the battery chemistry type via specific power capability, so that overall brake power is equal to the maximum battery charging power in a typical medium-sized passenger car under typical driving. This will maximise the regenerative braking energy whilst providing a larger torque assistance for a lower battery capacity. Dynamic simulation models were developed using GT-DRIVE software, emulating a mid-sized car with a 48V battery, and different turbocharged gasoline engines with motor-generator unit positions along a drivetrain. The 1.3 kWh battery pack was developed using a 14 Ah Lithium Iron Phosphate cell arranged in a 14 series 2 parallel configuration. A fuel economy comparison was produced using the FTP, WLTP, and HEFET drive cycles. When the motor-generator unit was attached via a synchronous belt, a 10-17% fuel saving was achieved in the WLTP drive cycle. Comparatively, when placing the electric machine after the clutch in a “P2” position, a 17-21% fuel saving was attained. The energy loss analysis of both P2 and P0 configurations revealed up to 7% overall reduction in total energy losses for the P2 setup. This was despite an increase in the motor-generator unit and battery losses due to the extended use of both in the electric-only mode capability with the P2 layout.
Alnamasi, Khaled, Terry, Simon, La Rocca, Antonino, Cairns, Alasdair
Real-time and Accurate Estimation of Road Slope for Intelligent Speed Planning System of Commercial Vehicle2020-01-01154/14/2020
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 estimation based on kinematics, considering the influence of road slope rate to estimate, the recursive least squares method with forgetting factor is used to estimate the road slope rate.Finally, the estimation results obtained by kinematics and dynamics are combined. It is expected that the error based on the algorithm-estimated slope value and the true slope value will be within 6% after the commercial vehicle is driving. The proposed algorithm has high accuracy, good real-time performance and strong stability. Using the commercial vehicle as a motion node and estimating the slope of a certain road, the intelligent planning of other vehicles’ speed in that region can be realized through the cloud platform. Then the fuel economy of the commercial vehicle can be improved.
Zhou, Mi, Tan, Gangfeng, Sun, Meng, Tian, Zhongpeng, Zhou, Fangyu, Liu, ZhiQiang
Requirements for Road Weather ApplicationsJ2945/3_202003 (Historical)3/24/2020
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 documentation (needs and requirements mapped to appropriate message exchanges). The purpose of this SAE Standard is to enable interoperability supporting these weather applications over a communications technology agnostic interface.
Infrastructure Applications Technical Committee
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