MEASUREMENT OF TIRE CHARACTERISTICS TRAVELING IN ACTUAL GROUND ENVIRONMENT WITH AN INSTRUMENTED VEHICLE

摘要

A conventional indoor tire testing system with a drum or a steel belt confines driving environment to limited conditions because of its structure. It is difficult to obtain tire characteristics for vehicles traveling on rough ground. In this study, an instrumented vehicle was introduced to measure the characteristics of a tire traveling in actual ground environment. Load cells, laser sensors, and a pair of linkage systems were implemented in the front two wheels of the vehicle. The load cells measure forces and moments in the 3-axis directions, the laser sensors measure the relative ground velocity, the moving direction and the effective radius of the tire, and the linkage system measures the tire orientation angles. The vehicle was tested on some rough grounds driven in a straight line or around in a circle. The data collected by the system revealed the characteristics such as the relationships between longitudinal slip ratio and the tractive force, and between sideslip angles and the lateral force on gravel road and grass ground as well as on asphalt road. Even though the signal from the sensor contained a lot of noise due to ground roughness, taking the average of the signal data showed reasonable values enough to indicate the tire characteristics. These relationships demonstrated that the instrumented vehicle is a useful device to obtain the characteristics of tire even on rough ground or unpaved roads, which is important for designing and evaluating performance of off-road vehicles.