A method to measure terrain parameters and drawbar pull for a six-wheeled vehicle on sand is proposed, tested and evaluated. The method is developed in order to be able to validate previously proposed tire/terrain models that are developed to simulate the behaviour of a six-wheeled vehicle with electric transmission on soft ground. Tests were performed at different tire pressures, and it is shown that the drawbar pull is vastly improved at lower tire pressure. Since the tire/terrain model uses terrain parameters such as pressure–sinkage and shear stress–displacement relationships, the sand properties are measured with a Bevameter. Parameters in the pressure–sinkage relationship are estimated to fit the measured data. Both external and internal shearing properties of the sand are measured using a rubber coated shear ring and a shear ring with grousers, respectively. The measured shear behaviour is shown to agree reasonably well with shear curves of simple exponential form. This will be a base in the development of a strategy to get improved cross country characteristics of six-wheeled vehicles with individually controlled electric transmission on soft ground.
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