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Development of a Parameter Identification Method for MF-Tyre/MF-Swift Applied to Parking and Low Speed Manoeuvres
Abstract A vehicle parking manoeuvre is characterized by low or zero speed, small turning radius and large yaw velocity of the steered wheels. To predict the forces and moments generated by a wheel under these conditions, the Pacejka Magic Formula model has been extended to incorporate the effect of spin (turn slip model) in the past years. The extensions have been further developed and incorporated in the MFTyre/MF-Swift 6.2 model. This paper describes the development of a method for the identification of the turn slip parameters. Based on the operating conditions of a typical parking manoeuvre, the dominant parameters of the turn slip model are firstly defined. At an indoor test facility, the response of a tyre under the identified operating conditions is measured. An algorithm is developed to identify the dominant turn slip parameters from the measured responses.
The Nonlinear Characteristics Impact of Multi-Staged Stiffness Clutch Damper on the Vehicle Creeping
Abstract The nonlinear characteristics impact of multi-staged stiffness clutch damper on the vehicle creeping is investigated by using the lumped-parameter modeling method as a certain mass-production passenger sedan is taken as the research subject. Firstly, a quasi-transient engine model of an inline four-cylinder and four-stroke engine, based on measured data of cylinder gas pressure versus crankshaft angle, is derived. Effective output torque is acquired and as the input excitation to the driveline system. Secondly, a 12-DOF (Degree of Freedom) nonlinear and branched powertrain system and vehicle longitudinal dynamics model is established. The differential mechanism characteristics and dynamic tire property based on the LuGre tire model are considered. Then, for a traditional two-staged stiffness clutch damper in consideration of hysteresis characteristics, vehicle powertrain system responses in both the time and frequency domain are obtained.
The Wagging Foot of Uncertainty: Data Collection and Reduction Methods for Examining Foot Pedal Behavior in Naturalistic Driving
Abstract Pedal misapplications may be rare, but the outcomes can be tragic. A naturalistic driving study with 30 drivers was conducted to gain a better understanding of foot pedal behaviors. Foot movements were observed from the moment subjects entered and positioned themselves in their vehicle, and continued through starting the ignition, shifting into gear, accelerating to driving speed, and finally, resting their foot after parking the vehicle. A coding methodology was developed to categorize the various foot movements and behaviors. Over 3,300 startup and parking sequences were coded. This paper describes the unique challenges involved in classifying foot movements and behaviors when drivers’ intentions are not known. For example, hesitant or interrupted foot movements often occurred when a driver was transitioning from a gas pedal press to a brake pedal press.
Abstract This paper outlines a real-time hierarchical control allocation algorithm for multi-axle land vehicles with independent hub motor wheel drives. At the top level, the driver’s input such as pedal position or steering wheel position are interpreted into desired global state responses based on a reference model. Then, a locally linearized rigid body model is used to design a linear quadratic regulator that generates the desired global control efforts, i.e., the total tire forces and moments required track the desired state responses. At the lower level, an optimal control allocation algorithm coordinates the motor torques in such a manner that the forces generated at tire-road contacts produce the desired global control efforts under some physical constraints of the actuation and the tire/wheel dynamics. The performance of the proposed control system design is verified via simulation analysis of a 3-axle heavy vehicle with independent hub-motor drives.
Robust Control of Regenerative and Hydraulic Brakes for Enhancing Directional Stability of an Electric Vehicle During Straight-Line Braking
Abstract Thanks to the actuation flexibility of their systems, electric vehicles with individual powertrains, including in-wheel and on-board motors, are a very popular research topic amongst various types of electrified powertrain architectures. The introduction of the individual electric powertrain provides great capacity for improvement of the vehicle’s energy efficiency and control performance. However, it also poses tremendous challenges concerning vehicle safety, due to the complex system dynamics and cooperation mechanisms between multiactuators. For an electric vehicle with independently controlled motors, because of design and manufacturing factors, the steady-state error of each motor output torque, and the flexibilities and nonlinear backlash of left and right drivetrains, can be different. This results in asymmetrical output characteristics of electric powertrain systems on the same axle.
This pneumatic spring terminology has been developed to assist engineers and designers in the preparation of specifications and descriptive material relating to pneumatic springs and their components. It does not include gas supply or control systems.
This lab test procedure should be used when evaluating the combined corrosion and fatigue performance for a particular coating system, substrate, process and design. The test is intended to provide an A to B comparison of a proposed coil spring design versus an existing field validated coil spring when subjected to the combined effects of corrosion and fatigue. The corrosion mechanisms covered by this test include general, cosmetic and pitting corrosion. Fatigue testing covers the maximum design stress and/or stress range of the coil spring design (typically defined as excursion from jounce to rebound positions in a vehicle). The effects of gravel and heat are simulated by pre-conditioning the springs prior to fatigue testing. Time dependant corrosion mechanisms such as stress corrosion cracking are not addressed with this test.
Any ROPS meeting the performance requirement of ISO 5700 (Static ROPS Test Standard) or ISO 3463 (Dynamic ROPS Test Standard) meets the performance requirements of this SAE Standard if the ROPS temperature/material and seat belt requirements of this document are also met. Fulfillment of the intended purpose requires testing as follows: A temperature-material requirement (6.9). This can be satisfied by using the appropriate materials or by performing any of the structural performance tests (Sections 7, 8, or 9) at -18 °C. A laboratory test, under repeatable and controlled loading, to permit analysis of the ROPS for compliance with the performance requirements of this document. Either the static test sequence (Section 7) or the impact test sequence (Section 8 ) shall be conducted. See Figure 1. A seat belt anchorage test (Section 10). The test procedures and performance requirements outlined in this document are based on currently available engineering data.
Fulfillment of the intended purpose requires testing as follows: A laboratory test, under repeatable and controlled loading, to permit analysis of the ROPS for compliance with the performance requirements of this SAE Standard. Either the static test (6.1) or the dynamic test (6.2) shall be conducted. A crush test to verify the effectiveness of the deformed ROPS in supporting the tractor in an upset attitude. A field upset test under reasonably controlled conditions, both to the rear and side, to verify the effectiveness of the protective system under actual dynamic conditions. (See 18.104.22.168 for requirements for the omission of this test). In addition to the laboratory and field loading requirements, there is a temperature-material requirement. (See 7.1.2.) The test procedures and performance requirements outlined in this document are based on currently available engineering data.
This SAE Information Report covers the important fundamental maintenance and service precautions for all off-road single-piece and multi-piece rims. Detailed information on specific procedures concerning mounting, demounting, maintenance and service of a particular type, style, or design of off-road rim assembly can be obtained by consulting rim or tire manufacturers or distributors. These procedures and service precautions are guidelines to be considered in preparation of the machine service manual and operator's manual and workplace procedures. It is the intent of this Information Report to allow for further development and review of these guidelines and then make this document a Recommended Practice.
The purpose of this SAE Recommended Practice is to provide a selection of disc wheels for industrial and agricultural application with a maximum of interchangeability. This is accomplished by establishing five groups of disc wheels, in each of which the hub mounting elements are common. These groups are designated 4 bolt, 5 in bolt circle; 5 bolt, 4.5 in bolt circle; 5 bolt, 5.5 in bolt circle; 6 bolt, 6 in bolt circle; and 8 bolt, 8 in bolt circle. Further, this document establishes an SAE part number and the maximum rated radial load for each standard wheel. In addition, the document requires the wheel manufacturer's name or trademark to be impression stamped on the wheel with location at the discretion of the manufacturer.
The SAE Recommended Practice establishes minimum performance requirements and related uniform laboratory test procedures for evaluating lateral (curb) impact collision resistance of all wheels intended for use on passenger cars and light trucks.
Balance Weight and Rim Flange Design Specifications, Test Procedures, and Performance Recommendations
This SAE Recommended Practice is intended to serve as a guide for standardization of features, dimensions, and configurations of balance weights for aluminum and steel wheels intended for use on passenger cars, light trucks, and multipurpose vehicles to assure good installation and retention of the balance weight. This document also provides test procedures and minimum performance requirements for testing balance weight retention.
This SAE Recommended Practice provides minimum performance requirements and uniform procedures for fatigue testing of wheels intended for normal highway use and temporary use on passenger cars, light trucks, and multipurpose vehicles. For heavy truck wheels and wheels intended to be used as duals, see SAE J267. For wheels used on trailers drawn by passenger cars, light trucks, or multipurpose vehicles, see SAE J1204. These minimum performance requirements apply only to wheels made of materials included in Tables 1 to 4. The minimum cycles noted in Tables 1 through 4 are to be used on individual test and a sample of tests conducted, with Weibull Statistics using 2 parameter, median ranks, 50% confidence level and 90% reliability, typically noted as B10C50.
The scope of the Landing Gear Integrity Programs (LGIP) Aerospace Recommended Practice (ARP) is intended to assist in the safe-life structural integrity management of the landing gear system and subsystems components. In addition, component reliability, availability, and maintainability is included in a holistic LGIP.
This SAE Aerospace Information Report (AIR) provides a methodology for performing a statistical assessment of gasturbine- engine stability-margin usage. Consideration is given to vehicle usage, fleet size, and environment to provide insight into the probability of encountering an in-service engine stall event. Current industry practices, such as ARP1420, supplemented by AIR1419, and engine thermodynamic models, are used to determine and quantify the contribution of individual stability threats. The statistical technique adopted by the S-16 committee for performing a statistical stability assessment is the Monte Carlo method (see Applicable References 1 and 2). While other techniques may be suitable, their application is beyond the scope of this document. The intent of the document is to present a methodology and process to construct a statistical-stability-assessment model for use on a specific system and its mission or application.
This SAE Aerospace Standard (AS) specifies minimum performance standards for Electronic Flight Information System (EFIS) displays that are head-down and intended for use in the flight deck by the flight crew in all 14 CFR Part 23, 25, 27, and 29 aircraft. This document is expected to be used by multiple regulatory agencies as the basic requirement for a technical standard order for EFIS displays.
Cadillac has aggressively used light materials for its recently-launched new cars, but for the all-new C1 architecture underpinning the XT5 crossover, engineers stuck with steel—and still achieved a major weight reduction.
Provide information and guidance for landing gear operation in cold temperature environment. Covers all operational aspects on ground and in flight. Includes effects on: tires, wheels, brakes, shock strut, seals, and actuation.
AS5714 MINIMUM PERFORMANCE STANDARD FOR PARTS 23, 27 and 29 AIRCRAFT WHEELS, BRAKES AND WHEEL AND BRAKE ASSEMBLIES
To assist the FAA with the technical update of TSO-C26d to address Electric Brake Actuation, standardize with TSO-C135a and address any remaining concerns with the current document.
This SAE Recommended Practice describes a marking system to distinguish long-stroke from standard stroke for service, parking, and combination air-brake actuators, roto-chambers, and components. Said actuators are used for applying cam and disc-type foundation brakes by slack adjuster means.
The new GTC4 Lusso is able to send up to 20% more torque to the front axle with a maximum 1400 N·m to either wheel and up to 90% of torque to the outer wheel during cornering, according to Michael Leiters.
Provide specifications for hydraulic fluids used in landing gear shock struts. Some of this information was previously in AIR5358 however specifications should be in an AS. This new document will contain the appropriate specifications for premixed hydraulic fluid with additives believed to improve fluid performance and reduce friction.
Minimum Performance Standard for Part 23, 27, and 29 Aircraft Wheels, Brakes, and Wheel and Brake Assemblies
This document was requested by the FAA to provide a technical update of TSO-C26d to address Electric Brake Actuation, standardize with TSO-C135a and address any remaining concerns with the current technical requirements in AIR5381.
The purpose of this SAE Aerospace Recommended Practice (ARP) is to provide a reasonable definition of external hydraulic fluid leakage exhibited by landing gear shock absorbers. The definition will outline normal and excessive leakage that is measureable and routinely encountered in newly assembled refurbished/remanufactured components, leakage during acceptance flights, recently delivered and in-service aircraft.
The electric-powered compressor complements a pair of sequential turbos. The flagship SQ7 also boasts 48/12V electrical system to power the e-booster and the car's EAWS.
Multi-material structures move mpg upward The quest to improve fuel economy is not waning, nor is the desire to achieve higher mpg through the use of just the right lightweight material for the right vehicle application. Cars poised to become 'a thing' Making automobiles part of the Internet of Things brings both risks and rewards. Agility training for cars Chassis component suppliers refine vehicle dynamics at the high end and entry level with four-wheel steering and adaptive damping. SAE 2016 World Congress Preview Technology trends and exhibitor products are highlighted in this special section, which features Toyota's plans for the show floor, tech sessions, and more.
Vehicles that use all four wheels to steer are more agile, easier to park, and safer to drive. In this episode of SAE Eye on Engineering, Editor-in-Chief Lindsay Brooke tests a new prototype four-wheel steering system from supplier ZF-TRW.
This SAE Standard specifies a method for measuring the deflection of friction materials, noise insulators, and disc brake pad assemblies to be used in road vehicles with a Gross Vehicle Weight Rating below 4336 kg. This part of the SAE J3079 includes the test for deflection and creep at various pressures under ambient temperature conditions. This SAE test method differs from SAE J2468 and ISO 6310 in the preload and maximum load applied to the test sample when deflection is measured. It also introduces additional measurements such as for deflection offset, hysteresis, and creep.
Parking Brake Control Identification - Vehicles with Hydraulic Brake Systems and Automatic Transmissions
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.).