Optimization of the inertial mass of the brake roller stand

Abstract

The article deals with the issues of modeling conditions for obtaining diagnostic information when checking the braking properties of cars on a roller stand.
As many studies show, roller stands of inertial type provide the most reliable information about the technical condition of the car. This concern, first of all, the parameters that determine the accuracy of simulation on the stand of real speed and thermal conditions. The accuracy of diagnosing the brake system of a car on an inertial test bench depends on many factors. One of the determining factors is the value of the reduced masses of rotating elements in the "car-stand" system: rollers, wheels and car transmission parts. The main design parameter of the inertial roller stand is the diameter of the roller. The reduced mass of the transmission can be determined by measuring the moments of inertia of its individual parts and bringing them to a given axis. But this is a laborious process and takes a lot of time. At the same time, the reduced mass of the transmission is also variable due to the wear of parts. Therefore, methods are required to determine the reduced mass of the transmission of a particular vehicle, regardless of the degree of wear of parts.
To determine the reduced mass of the transmission, two modes of acceleration of the car on the stand are used: acceleration from the drive of the stand, while two wheels of the car rotate; acceleration from the stand drive, in which one wheel of the car rotates. The analysis of these modes is made and the equations for determination of the reduced mass of transmission are made.
The analysis of changes in the moments of inertia of the wheel and rotating parts of the car, as well as the radius of the wheel is carried out. Based on this, the general variation of the reduced mass of the wheel and associated rotating parts of the vehicle is presented. This variation can have a significant impact on the accuracy of diagnosis. The optimal way to compensate for this uncertainty may be to increase the reduced mass of the stand so that the proportion of the reduced mass of the wheel and the associated rotating parts of the car is a small part and introduces an error no more than acceptable.