Papers by Keyword: Adhesion Coefficient

Abstract: The current accelerated developments within the automotive sector have triggered a series of performance, comfort, safety and design-related issues. Hence, oftentimes manufacturers are challenged to combine various elements so as to achieve an attractive design, without diminishing the vehicle’s dynamic performance. In order to determine the vehicle dynamic performances we carried out an analysis by two methods. In the first part of the paper, we have used the analytical method to establish the dynamic performances of a vehicle. The second part of our study addresses another method to determine the star performances of the vehicle by means of computerized simulations. The first test aimed to determine vehicle starting performances for two vehicle models, with similar technical configuration, but with the same initial data. In the second test, we aimed at determining the start performance for the same car model, with the same initial data, but for different adhesion coefficients

Abstract: This paper describes the main properties of the soil, in the analysis of the soil under the horizontal load stress distribution and stress - deformation relationship on the basis of research issues related to wheeled vehicles and tracked vehicles traction. The formula gives the vehicle traction, analyzes the factors that affect vehicle traction and proposes an effective method to improve vehicle traction.

Abstract: In order to complete road identification, dynamic identification interval is built according to the six typical road adhesion coefficients which don’t overlap with each other, using road adhesion coefficient as its parameter index under Burckhardt model. It’s concluded from simulation tests about single road and variational road based on brake single wheel model that this method is capable of managing to conduct road identification accurately and immediately, realizing automatic identification under real-time slip rate and correcting identification errors automatically.

Abstract: This paper presents an electronic differential control strategy based on equal adhesion coefficient, it makes electric vehicle (EV) with two dual-motorized-wheels achieve differential by distributing and controlling the driving torque. First, six degree-of-freedom (6-DOF) vehicle dynamic model was set up and electronic differential system based on permanent magnet synchronous motor (PMSM) vector control was designed, then the simulation of differential control method with Matlab/Simulink was performed. The results show that when the high-speed vehicle steering in the low road adhesion coefficient, the electronic differential control method based on the principle of equal adhesion coefficient can keep two driving wheels’ adhesion coefficient utilization ratio the same, avoiding single wheel skid and improving the steering stability.

Abstract: Adhesion coefficient between tire and road is one of important factors which influence vehicle safety performance. On the basis of theoretical analysis, the detection method of adhesion coefficient based on brake-by-wire is put forward. Brake force is estimated according to pedal position sensor, vehicle braking deceleration is detected through MMA6260Q acceleration sensor. Motion state of tire is distinguished according to brake force and road braking force, vertical load of tire is received in view of formula on vehicle load transfer. Adhesion coefficient used for sliding area is got and taken as adhesion coefficient of road. Analysis shows that the detection method may identify adhesion coefficient between tire and road accurately, and has certain practical value.

Abstract: The number of traffic accidents caused by ice and snow is generally three to four times higher than that in normal condition. In order to improve safety level when driving on ice and snow pavement, adhesion coefficient is a vital parameter need to be analyzed. The relations between adhesion coefficient and temperature, relative humidity, snow’s thickness, snow’s compactness were studied. And their relation models were established. These models may provide the basis for the road administration department to conduct traffic control decision-making according to the weather condition and the state of ice and snow.

Abstract: The braking problems of vehicle on icy and snowy roads are analyzed. The acceleration data in the process of reducing speed was collected by an accelerometer. The rules of brake force changing and the acceleration were studied too. A simple calculation adhesion coefficient model was constructed and used to estimate the braking parameters. The curves of brake adhesion coefficient were also got. It is a available method to use an accelerometer to deduce the tires adhension characteristic.

Abstract: Through analyzing the process of brake, a dynamic model of automobile and a model of the relationship between braking distance and adhesion coefficient were formed; also a simulation calculating model of braking distance was established with the use of Matlab. Finally, a research was done toward the braking distance of a type of a car running on a road after using snow-melting agent. On one hand, with the application of the simulation model which has been established, calculations have been done to the braking distance of Bora vehicles running on roads after using deicing salt; on the other hand, by experiments, Bora vehicles’ braking distance and maximum braking deceleration under the same road condition were measured, meanwhile, the established simulation model was verified.