Abstract
Measurement of road surface friction coefficient is significant to improve advanced driver-assistance systems (ADAS)．Almost of ADAS use the information obtained from wheel speed sensors, acceleration sensors, etc. However, it is difficult to measure the road surface friction coefficients accurately with these sensors. Therefore, in order to develop an intelligent tire capable of measuring the road surface friction coefficients, various studies focus on tires that are the only parts of a car being grounded on road surface. However, such an intelligent tire has not been put to practical use due to the difficulty of stable measurement of deformation induced on a tire and difficulty in estimating the road surface friction coefficients from the deformation of the tire. Therefore, this study focuses on the deformation of a wheel and proposes a method to measure road surface friction coefficients from strains induced on the surface of not a tire but a wheel. The study clarifies the relationship between the strains on a wheel and the loads acting on the tire from the grounding surface by using an experimental apparatus capable of simulating complete slip running. In addition, a simple method of measuring road surface friction coefficients is proposed by means of the obtained relationship.
