Browse Topic: Moment

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Vehicle Yaw Stability Model Predictive Control Strategy for Dynamic and Multi-Objective Requirements2024-01-23244/9/2024
Vehicle yaw stability control (YSC) can actively adjust the working state of the chassis actuator to generate a certain additional yaw moment for the vehicle, which effectively helps the vehicle maintain good driving quality under strong transient conditions such as high-speed turning and continuous lane change. However, the traditional YSC pursues too much driving stability after activation, ignoring the difference of multi-objective requirements of yaw maneuverability, actuator energy consumption and other requirements in different vehicle stability states, resulting in the decline of vehicle driving quality. Therefore, a vehicle yaw stability model predictive control strategy for dynamic and multi-objective requirements is proposed in this paper. Firstly, the unstable characteristics of vehicle motion are analyzed, and the nonlinear two-degree-of-freedom vehicle dynamics models are established respectively. Secondly, the vehicle yaw stability control strategy is designed: The two-line method is used to extract the boundary of β−β̇ phase portrait. On this basis, the geometric distance quantization method is applied to establish the dynamic mapping relationship between the multi-objective requirements of driving stability, yaw maneuverability, actuator energy consumption and the weight of YSC cost function in different vehicle stability states. The model predictive theory and rule-based single wheel differential braking technology are applied to achieve vehicle stability control. Finally, a joint simulation platform is built based on vehicle dynamics simulation software CarSim and MATLAB/Simulink for testing and verification. The simulation results show that the YSC designed in this paper can adaptively adjust the controller output according to the dynamic multi-objective requirements in different vehicle stability states, and effectively improve the driving quality of the vehicle under strong transient conditions.
Wang, Hanlin, Wu, Jian, Chen, Zhicheng, He, Rui, Li, Haiqiao
Energy Efficiency of Distributed-Drive Articulated Vehicle by Differential Steering2021-01-09694/6/2021
Differential steering mode of distributed-drive articulated vehicle is proposed by using the characteristics of independent in-wheel motor. The compound steering system of articulated vehicle is composed of fully hydraulic steering system and differential steering. Several differential steering modes of articulated vehicle are presented, and the differential steering dynamic model of articulated vehicle is built to investigate the relationship of yaw moment and turning radius. The differential steering control strategy of articulated vehicle is studied while maintaining the vehicle in the stability domain. The energy consumption of articulated vehicle with differential steering is calculated by simulating vehicle single shift lane steering process. The simulation results show that the articulated vehicle with differential steering can reduce the energy consumption of hydraulic steering system up to 3.8%. It indicates that the articulated vehicle with compound steering system can realize the energy efficiency by torque vectoring control of each in-wheel motor.
Shen, Yanhua, Liu, Zixiang
ADAS Day 2 Keynotes1288012/16/2020
Challenges in Developing L2/L3 AD Systems on Global Roadways Development and Application of a Collision Avoidance Capability Metric (SAE Paper 2020-01-1207) This paper describes the development and application of a newly developed metric for evaluating and quantifying the capability of a vehicle/controller (e.g., Automated Vehicle or human driver) to avoid collisions in nearly any potential scenario, including those involving multiple potential collision partners and roadside objects. At its core, this Collision Avoidance Capability (CAC) metric assesses the vehicle�s ability to avoid potential collisions at any point in time. It can also be evaluated at discrete points, or over time intervals. In addition, the CAC methodology potentially provides a real-time indication of courses of action that could be taken to avoid collisions. The CAC calculation evaluates all possible courses of action within a vehicle�s performance limitations, including combinations of braking, accelerating and steering. Graphically, it uses the concept of a �friction ellipse�, which is commonly used in tire modeling and vehicle dynamics as a way of considering the interaction of braking and turning forces generated at the tire contact patches. When this concept is applied to the whole vehicle, and the actual or estimated maximum lateral and longitudinal accelerations of which the vehicle is capable are normalized, the ellipse becomes a circle that represents the boundaries of vehicle performance that can be utilized for driving, including evasive action. When a potential conflict with another object (e.g., another vehicle or pedestrian) is present, the CAC classifies operating areas within the circle as either successful (avoiding a collision) or not successful (resulting in a collision). The capability of a vehicle to avoid a collision is reflected in CAC, as CAC is larger when the range of possible successful avoidance maneuvers is larger and smaller when the range of possible successful avoidance maneuvers is smaller. Development and derivation of the CAC are described, and various simulated and real-world test scenarios are described and evaluated.
Marnat, Christophe
Force and Moment Test MethodJ1987_202006 (Current)6/19/2020
This SAE Recommended Practice describes the determination of passenger car and light truck tire force and moment properties on a belt-type flat surface test machine. It is suitable for accurately determining five tire forces and moments in steady-state under free-rolling conditions as a function of slip angle and normal force which are incrementally changed in a given sequence.
Highway Tire Committee
New Control Method of Four-Wheel Independent Driving Electric Vehicles for Anti-Slip Purpose2020-01-14204/14/2020
The performance of electric vehicles could be enhanced by more flexible drivetrain configurations combined with advanced control methods. Based on four wheel independent driving and front and rear axle modular steering configuration, which was proposed by our research group last year, the problem of slippery under close-to-limit conditions are further discussed and simulated. A new torque vectoring method based on obtainable parameters and variables in real driving situations is introduced to reduce the sideslip when turning on low friction surfaces or with high speed. This method is developed from a comprehensive index, which reflects the stability and maneuverability, by adding additional torques when stability could not be compensated enough by basic torque vectoring. Besides, an improvement of adding a simu-Torsen differential mechanism is made to the model of the vehicle, which enables another control method with the same purpose as before. This method is combined with the torque vectoring and the active control to switch on the simu-Torsen differential mechanism. All the control methods were validated with a real SUV based Simulink model. The vehicle responses with each control method and without such controllers are compared to describe its strengths in detail. Both control method could help the vehicle keep the designated speed and turning curvature without losing its attitude or severe sideslip. The method with simu-Torsen differential mechanism would have a better robustness as it is designed to be able to be operated manually during system malfunction while the other one could reduce the wear and tear of the tyres.
Liu, Chen, Zheng, Gangtie
Development and Application of a Collision Avoidance Capability Metric2020-01-12074/14/2020
This paper describes the development and application of a newly developed metric for evaluating and quantifying the capability of a vehicle/controller (e.g., Automated Vehicle or human driver) to avoid collisions in nearly any potential scenario, including those involving multiple potential collision partners and roadside objects. At its core, this Collision Avoidance Capability (CAC) metric assesses the vehicle’s ability to avoid potential collisions at any point in time. It can also be evaluated at discrete points, or over time intervals. In addition, the CAC methodology potentially provides a real-time indication of courses of action that could be taken to avoid collisions. The CAC calculation evaluates all possible courses of action within a vehicle’s performance limitations, including combinations of braking, accelerating and steering. Graphically, it uses the concept of a “friction ellipse”, which is commonly used in tire modeling and vehicle dynamics as a way of considering the interaction of braking and turning forces generated at the tire contact patches. When this concept is applied to the whole vehicle, and the actual or estimated maximum lateral and longitudinal accelerations of which the vehicle is capable are normalized, the ellipse becomes a circle that represents the boundaries of vehicle performance that can be utilized for driving, including evasive action. When a potential conflict with another object (e.g., another vehicle or pedestrian) is present, the CAC classifies operating areas within the circle as either successful (avoiding a collision) or not successful (resulting in a collision). The capability of a vehicle to avoid a collision is reflected in CAC, as CAC is larger when the range of possible successful avoidance maneuvers is larger and smaller when the range of possible successful avoidance maneuvers is smaller. Development and derivation of the CAC are described, and various simulated and real-world test scenarios are described and evaluated.
Silberling, Jordan, Wells, Paul, Acharya, Atul, Kelly, Joseph, Lenkeit, John
Flow around a Heavy Vehicle in a Side Wind2019-01-50193/21/2019
Driving stability can be an issue for heavy vehicles. In a side wind, a side force and rolling moment will develop, and they both affect driving stability, from which the vehicle may overturn. It is important to understand the flow structure in order to prevent a truck from rolling over. The main purpose of this study is to investigate the flow around a heavy vehicle that causes it to overturn. A 1/8 scaled, simplified tractor/trailer configuration called the Ground Transportation System (GTS) with Reynolds number (based on the GTS width) equal to 1.6 × 106 was used for this study. A side wind was modeled by turning the GTS model with respect to its moment reference point. A triangular mesh was used for the truck and the computational domain surfaces, while hybrid meshes filled the computational domain volume. The Ansys® CFX code based on the k-ω shear stress transport (SST) turbulence model was used to solve the governing equations numerically for an incompressible fluid. All results were averaged for 50 shedding periods. The simulation was done for yaw angles of 0-14°, and the results were compared with experimental data from the literature. To model an open road, a moving-ground boundary condition was implemented in the simulation. The computational fluid dynamics calculations for the drag, side force, and rolling moment coefficient had more than 90% accuracy. The other aerodynamic coefficients had larger discrepancies due to the moving-ground boundary condition and an under-prediction of the pressure distribution on the front corner radius of the GTS. In general, it was found that the present simulation can capture the trends for most aerodynamic coefficients. This study showed that the rolling moment, which determines the tendency to overturn, is sensitive to the spanwise pressure at the rear of the vehicle.
Levin, Jeffrey, Chen, Shih-Hsiung
Identification of Blocked Forces and Moments of an Oil Pump Fixed on a Test Bench by Using an Inverse Vibration Technique2018-01-15026/13/2018
The major difficulty of the structure borne noise source characterization is the strong dependence of the coupling forces with respect to the input mobility of the reception structures and/or the mechanical link between the source and the receiver. The placement of a force sensor can then be too intrusive and the use of inverse techniques on the real reception structure is difficult to apply, because the accessibility can be limited and tests must then be applied for all structures likely to be linked with the studied source. The aim of this paper is to propose a general technique to identify the intrinsic characteristics that are the blocked forces and moments on a simple test bench hosting the source. The test bench consists in mounting the source on a vibrating beam where the mechanical link corresponds exactly to the link between the source and the final receiver. The vibration displacement field of the beam is then measured in two configurations: when the source is switched on and when the source is switched off while the beam is excited by a shaker. The application of the RIFF technique (also known as Force Analysis Technique) allows one to identify the force distribution applied to the beam. The second configuration (beam excited by the shaker) enable the identification of the force distribution due to the attachment of the source only. This force distribution can then be used to correct the beam equation of motion such that the effect of the link can be avoided. The RIFF technique can then be used to identify the blocked force distribution from the displacement measured in the first configuration (source switched on). The interest to identify the force distribution is that is it is possible to extract forces and moments applied to attached points by the source thanks to local spatial integrations around each attachment points. In this paper, the considered source is a oil pump that can be mounted on different engines. The study focuses on the blocked forces and moments applied by two close attachment points. Two post-processing are then proposed, the first consists in extracting forces and moments for each point, the second consists in calculating the equivalent force and equivalent moment applied by both points. Results are shown for all of these proposal, demonstrating the interest to consider the equivalent forces and moments in the low frequency domain.
PEZERAT, Charles, Chevillotte, Fabien
Efficient Direct Yaw Moment Control during Acceleration and Deceleration While Turning (Second Report)2016-01-16774/5/2016
Electric vehicles (EVs) are attracting attention due to growing awareness of environmental issues such as fossil fuel depletion and global warming. In particular, a wide range of research has examined how direct yaw moment controls (DYCs) can enhance the handling performance of EVs equipped with multiple in-wheel motors (IWMs) or the like. Recently, this research has focused on reducing energy consumption through driving force distribution control. The first report proposed a method to minimize energy consumption through an efficient DYC for extending the cruising range of a vehicle installed with four IWMs, and described the vehicle behavior with this control. Since motors allow high design flexibility, EVs can be developed with a variety of drive systems. For this reason, various driving force distribution control methods can be considered based on the adopted system. Widespread adoption of the optimum driving force distribution control method for each drive system from the standpoint of energy consumption should be achievable using the results described in the first report. Consequently, this second report examines a control method to minimize energy consumption for vehicles with different motor-based drive systems. The driving force distribution control laws to minimize energy consumption in a vehicle with two or three motors were calculated and compared to a vehicle with four motors. This paper also compares the energy consumption when turning while accelerating or decelerating, and discusses the vehicle behavior in these scenarios. The derived control laws can be applied to vehicles with any motor-based drive system.
Himeno, Hiroshi, Katsuyama, Etsuo, Kobayashi, Takao
Efficient Direct Yaw Moment Control during Acceleration and Deceleration while Turning (First Report)2016-01-16744/5/2016
The research described in this paper aimed to study the cornering resistance and dissipation power on the tire contact patch, and to develop an efficient direct yaw moment control (DYC) during acceleration and deceleration while turning. A previously reported method [1], which formulates the cornering resistance in steady-state cornering, was extended to so-called quasi steady-state cornering that includes acceleration and deceleration while turning. Simulations revealed that the direct yaw moment reduces the dissipation power due to the load shift between the front and rear wheels. In addition, the optimum direct yaw moment cancels out the understeer augmented by acceleration. In contrast, anti-direct yaw moment optimizes the dissipation power during decelerating to maximize kinetic energy recovery. The optimization method proved that the optimum direct yaw moment can be achieved by equalizing the slip vectors of all the wheels. This research also found that this control method enhances the stability of vehicle motion.
Kobayashi, Takao, Katsuyama, Etsuo, Sugiura, Hideki, Ono, Eiichi, Yamamoto, Masaki
An Effect Study of Passenger Car Radial Tire Contour Design Theory on Tire Force and Moment Properties2016-01-04464/5/2016
A 3D finite element (FE) model of a radial tire 205/55R16, established using ABAQUS software, is utilized to simulate tire force and moment properties. Drum tests are designed to validate the FE model’s reliability. To investigate the impacts of PCR contour design theory on tire force and moment, a modified string balance contour theory is presented. Based on string balance contour theory, it simplifies the shape of belt pressure share ratio as a trapezium. Besides, a program for calculating tire contour curve is compiled using MATLAB software. Applying different belt pressure share ratios, diverse tire contours are designed. One of the contours is selected according to its positive effect on cornering stiffness in simulation. From comparison of the selected newly designed tire and the original tire, it is found that the newly designed tire’s contact patch area, longitudinal stiffness, lateral stiffness, inclination stiffness and cornering stiffness increase while its radial stiffness decreases. The results show that the new contour design theory can improve tire force and moment properties, thus improving vehicle handling and riding comfort performances.
Liang, Chen, Wang, Guolin, Zheng, Zhou
Reducing Torque Measurement Uncertainty in Turbine Engine TestingTBMG-244334/1/2016
Torque is among the most important of all the measured quantities in applications ranging from characterizing high-power gas turbines, to determining the level of force required to open a screw cap on a medication container. As anyone who studied physics in high school should recall, torque is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Loosely speaking, torque is a measure of the turning force on an object such as a bolt or a flywheel. For example, pushing or pulling the handle of a wrench connected to a nut or bolt produces a torque (turning force) that loosens or tightens the nut or bolt. However, measuring torque accurately can be far from straightforward. This article offers an overview of one approach to reducing uncertainty in torque measurement using an example of turbine engine testing to illustrate the process.
About the Effect of Camber Control on Vehicle Dynamics2014-01-23839/30/2014
In recent years, the conversion of vehicles to electric power has been accelerating, and if a full conversion to electric power is achieved, further advancements in vehicle kinematic control technology are expected. Therefore, it is thought that kinematic performance in the critical cornering range could be further improved by significantly controlling not only the steering angle but also the camber angle of the tires through the use of electromagnetic actuators. This research focused on a method of ground negative camber angle control that is proportional to the steering angle as a technique to improve maneuverability and stability to support the new era of electric vehicles, and the effectiveness thereof was clarified. As a result, it was found that in the critical cornering range as well, camber angle control can control both the yaw moment and lateral acceleration at the turning limit. It was also confirmed that both stability and the steering effect in the critical cornering range are improved by implementing ground negative camber angle control that is proportional to the steering angle using actuators. Dramatic improvements in cornering limit performance can be achieved by implementing ground negative camber angle control that is proportional to the steering angle.
Yoshino, Takahiko, Nozaki, Hiromichi
Implementation of an Electronic Differential Using Torque Vectoring2014-01-17764/1/2014
This paper involves the study of implementation of an active electronic differential using torque vectoring in an electric rear wheel drive vehicle. The proposed system works in a closed loop taking feedback in real time from sensors which provides inputs for steering angle, throttle position, angular velocity of wheels, yaw rate, yaw acceleration, longitudinal acceleration and lateral acceleration. The objective of this system is to i) increase the stability and the vehicle response to the driver while turning, and ii) use the traction available on the driven wheels more efficiently. The system involves applying a torque difference between the rear driven tires to create a moment about the centre of mass that causes yaw acceleration and aids in turning the car by increasing yaw rate. The effect of drag forces and the lateral forces on the tires have been included. An optimized desired moment is calculated which is applied via torque difference while turning. A Permanent Magnet DC (PMDC) motor model and a model for the motor controller in torque mode have been developed based on experimental response analysis on a jig setup. A detailed race car model for longitudinal vehicle dynamics is derived from forces acting on the car including the effect of losses due to drag forces, rolling resistance, transmission inefficiency and inertial losses. To validate the proposed system, various throttle profiles and steering inputs are simulated on the vehicle model during a turn. The results are compared to the case when vehicle is turning without using torque differential.
Sakhalkar, Siddhesh, Dhillon, Parveen, Kumar, Pranay, Bakshi, Soovadeep, Arora, Puneet Singh
Studs, Installation Practice for Interference Fit - MetricMAP1670 (Historical)5/9/2006
This document provides a recommended practice for installation of interference fit studs into threaded holes in non-ferrous alloys such as aluminum or magnesium.
E-25 General Standards for Aerospace and Propulsion Systems
Tire Forces and Moments and On-road Lateral Stability of Articulated Steer Vehicles2005-01-359711/1/2005
The on-road lateral stability of an articulated steer vehicle is investigated for both small and high deviations. First, for small deviations, a linear model of the vehicle is devised and analyzed. This planar model is generated based on some simplifying assumptions. For instance, the equations describing the tire forces and moments are linearized, and the tire rolling resistance is neglected. A linear stability analysis of the straight line motion of the vehicle with constant forward speed is conducted by using this simplified model for different values of the torsional stiffness and damping at the articulation joint. To investigate the lateral stability of the vehicle at higher deviations, the motion of a virtual prototype of the vehicle in ADAMS/View is simulated for different conditions. Finally, the results from the simulations and the linear stability analyses are compared. These comparisons show that the tire rolling resistance can change effectively the results predicted by the linear analysis. In addition, at higher deviations, the effects of the nonlinearity of the tire aligning moment behavior appear and thus, the dynamic behavior is significantly different from that predicted by the linear analysis.
Azad, N. L., McPhee, J., Khajepour, A.
Directional Response Analysis of Tractor-Trailer with Multi-Axle-Steering Carrying Liquid Load2005-01-04154/11/2005
As a bulk-liquid transport vehicle executes a turning maneuver, the liquid within the tank sloshes from side to side, prompting lateral and moment forces, which can result in a serious roll instability of the vehicle. It is well known that lateral acceleration forces play a key contributory role in the rollover of tankers. This paper investigates the yaw/roll dynamics of tractor-trailer with multi-axle-steering carrying a partial load of liquid during a transient steering operation for various levels of tank filling. First, the lateral acceleration forces and the vertical and lateral translations of the center of mass of a liquid-carrying tanker fitted with multi-wheel steering under conditions of steady-state steering response are presented. Next, the transient directional responses of yaw and roll angles are also studied in simulations of a lane change maneuver. The results demonstrate that the use of multi-axle-steering reduces the lateral forces caused by shifts of the liquid during steady turning, hence reducing roll and lateral instabilities of the vehicle. The present results are compared to those of a conventional tanker fitter with a single front wheel steerable axle.
Wu, Der-Ho, Lin, Yu-Hung
Directional Dynamics of a Partly-Filled Tank Vehicle Under Braking and Steering2000-01-347712/4/2000
Dynamic behavior of a partly-filled liquid cargo vehicle subject to simultaneous application of cornering and braking maneuvers is investigated through computer simulation. A three-dimensional quasi-dynamic model of a partly-filled tank of circular cross-section is developed and integrated into a comprehensive three-dimensional model of an articulated vehicle to study its directional response under varying steering and braking inputs, fill volumes and road surface friction. The liquid load movement encountered under combined steering and braking is expressed in terms of variations in the instantaneous c.g. coordinates and mass moments of inertia of the liquid bulk, assuming negligible influence of fundamental slosh frequency and viscous effects. The dynamic response characteristics of the partly-filled tank vehicle under braking and turning are presented in terms of resulting cargo load shift, moments induced by the cargo movement, load transfer ratio, yaw and roll response, and braking performance of the vehicle. The response characteristics of the partly-filled tank vehicle are compared with those of an equivalent rigid cargo vehicle to demonstrate the impact of the liquid load shift under combined turning and braking maneuvers. The results of the study reveal that a partly-filled articulated tank vehicle, subject to braking in a turn, is more susceptible to rollover on dry roads, while it exhibits a higher propensity of trailer swing on slippery roads.
Kang, X., Rakheja, S., Stiharu, I.
Aircraft TowbarARP1915A (Historical)5/1/1991
This SAE Aerospace Recommended Practice (ARP) outlines the basic general design considerations for aircraft towbars.
AGE-3 Aircraft Ground Support Equipment Committee
Aircraft TowbarARP1915 (Historical)3/1/1985
This Aerospace Recommended Practice (ARP) outlines the basic general design considerations for aircraft towbars.
AGE-3 Aircraft Ground Support Equipment Committee
LABORATORY TESTING MACHINES AND PROCEDURES FOR MEASURING THE STEADY STATE FORCE AND MOMENT PROPERTIES OF PASSENGER CAR TIRESJ1107_197501 (Historical)1/1/1975
This Information Report presents background and rationale for SAE Recommended Practice J1106, Laboratory Testing Machine and Procedures for Measuring the Steady Force and Moment Properties of Passenger Car Tires. The purpose of SAE J1106 is to define standards for equipment design and test procedures so that data from different laboratories can be directly compared. Whereas such standardization is not a requirement for testing associated with tire development, it is necessary in the context of vehicle design and tire selection problems. The basic approach employed in developing SAE J1106 was to consolidate and document existing technology as embodied in equipment and procedures currently employed for routine tire evaluations. Equipment and procedures whose current use is restricted to research applications were not considered. Research experience is discussed in this Information Report, however, to the extent deemed necessary to provide background and rationale for SAE J1106. Material is therefore included on speed effects, contaminants dynamic testing, traction, surface geometry, and other subjects not considered in SAE J1106. The scope was expanded in an effort to anticipate questions raised by SAE J1106.
Highway Tire Committee
Bending Moments in the Master Rod of a Radial Aircraft Engine3200691/1/1932
HEREIN are presented the results of an investigation of the bending moments in the master rod of a radial aircraft engine by a graphical method, and a simple formula derived therefrom for approximating this moment in similar engines. The bending stress in the master rod comes from turning moments about the crankpin axis caused by the action of the articulated rods due to gas-pressure and inertia forces and also by the inertia forces in the master rod itself. Charts are presented that show the magnitude and fluctuation of these turning moments. Accurate computation of these moments involves much tedious work. A method of approximating them with sufficient accuracy for engineering purposes is given for the case of a nine-cylinder radial aircraft engine. The method is applicable also to non-radial engines and to radial engines having other than nine cylinders, but in these cases investigation of the turning moments due to the gas loads in certain cylinders seems advisable.
Taylor, C. F.
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