Influence of Track-Assembly Geometryon Mobility Over Rigid Terrai

Abstract

This thesis considers the modeling and simulation of tracked vehicles. Specifically it aims to investigate how the geometry of the track-assembly affects its mobility over rigid obstacles. This is done with the purpose of aiding in the Swedish Defence Research Agency’s (FOI) goal of developing parametrized virtual models of tracked vehicles for researching mobility. The vehicle is modeled as a multibody dynamics simulation consisting of rigid bodies. This entails solving index-3 differential algebraic equations (DAE) with high precision. The validation of the vehicle model and simulation included the comparison of two methods of solving the DAE in question, both of which require the solving of a saddle point problem. Thus for each method two iterative saddle point problem solvers have been compared as well. After choosing a numerical method the mobility of the model is evaluated on rigid obstacles with varying track-assembly geometry. The evaluation shows that the track-assembly geometry significantly impacts the models ability to traverse vertical step obstacles and half round obstacles. The results suggest that this applies to a general real tracked vehicle, however a more thorough model validation and investigation into the numerical methods is required to draw any quantitative conclusions.