Title: The dynamic rolling radius of a pneumatic tyre on hard terrains

Authors: Herman A. Hamersma; Theunis R. Botha; P. Schalk Els

Addresses: Department of Mechanical and Aeronautical Engineering, University of Pretoria, Hatfield 0028, South Africa ' Department of Mechanical and Aeronautical Engineering, University of Pretoria, Hatfield 0028, South Africa ' Department of Mechanical and Aeronautical Engineering, University of Pretoria, Hatfield 0028, South Africa

Abstract: Extensive research was done on the rolling radius of a tyre from the 1960s to the 1980s, specifically looking at the tractive performance of tractors and agricultural vehicles. The research was limited to investigating slip conditions at low vehicle speed where it was safe to assume that the rolling radius is static or quasi-static. This paper revisits some of these investigations, and looks at the validity of the static or quasi-static rolling radius assumption on hard, high friction and uneven surfaces at higher speeds. The aim is to establish whether the rolling radius defined under static conditions can be used to estimate tyre contact patch velocity, a state needed to determine longitudinal tyre slip. Longitudinal tyre slip plays a crucial role in the performance of advanced driver assist systems. It is known that these systems' performance decreases on rough roads when the static rolling radius assumption may become inaccurate.

Keywords: kinematic rolling radius; kinetic rolling radius; tyre contact patch velocity; digital image correlation; wheel force transducer measurements; tyre modelling; dynamic rolling radius; pneumatic tyres; hard terrain; uneven surfaces; longitudinal tyre slip; advanced driver assistance systems; ADASA; rough roads.

DOI: 10.1504/IJVSMT.2016.080879

International Journal of Vehicle Systems Modelling and Testing, 2016 Vol.11 No.3, pp.234 - 251

Received: 04 Aug 2016
Accepted: 02 Sep 2016
Published online: 09 Dec 2016 *

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