Browse Topic: Moment
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
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.
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
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
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
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
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
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.
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
This document provides a recommended practice for installation of interference fit studs into threaded holes in non-ferrous alloys such as aluminum or magnesium.
This SAE Aerospace Recommended Practice (ARP) outlines the basic general design considerations for aircraft towbars.
This Aerospace Recommended Practice (ARP) outlines the basic general design considerations for aircraft towbars.
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
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