Riassunto analitico
The design of a suspension system is delicate balancing act between various vehicle dynamics’ parameters. The variation of one parameter could negatively impact another. A key tool in the design phase are accurate models of vehicle components to analyse the effects of making parameter changes. In the current thesis work, two kinematic and compliant models are created of a double wishbone suspension, a rigid model, as well as a model with elastic elements like bushings. The model will calculate key kinematic parameters: toe, camber and sideview angle, wheelbase and wheel track variation as well as the motion ratio and vertical force using wheel displacement or vertical force as an input.
In the first part the position and force constraints are developed for a rigid double wishbone suspension. A nonlinear solver calculates the required parameters for certain wheel displacement or vertical force. The rigid model is used as a basis to develop the suspension model with elastic elements. The bushings are modelled as an nonlinear elastic element that extrapolates the deformation from the reaction forces.
In the next phase, both models are validated by performing a parallel wheel travel simulation with the model and comparing the results with the multi-body simulation software MSC ADAMS Car. The results from the model have an excellent correlation with MSC ADAMS Car software. The benefits of the model is in the simplicity of analysing design changes on the kinematic and compliant parameters.
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Abstract
The design of a suspension system is delicate balancing act between various vehicle dynamics’ parameters. The variation of one parameter could negatively impact another. A key tool in the design phase are accurate models of vehicle components to analyse the effects of making parameter changes. In the current thesis work, two kinematic and compliant models are created of a double wishbone suspension, a rigid model, as well as a model with elastic elements like bushings. The model will calculate key kinematic parameters: toe, camber and sideview angle, wheelbase and wheel track variation as well as the motion ratio and vertical force using wheel displacement or vertical force as an input.
In the first part the position and force constraints are developed for a rigid double wishbone suspension. A nonlinear solver calculates the required parameters for certain wheel displacement or vertical force. The rigid model is used as a basis to develop the suspension model with elastic elements. The bushings are modelled as an nonlinear elastic element that extrapolates the deformation from the reaction forces.
In the next phase, both models are validated by performing a parallel wheel travel simulation with the model and comparing the results with the multi-body simulation software MSC ADAMS Car. The results from the model have an excellent correlation with MSC ADAMS Car software. The benefits of the model is in the simplicity of analysing design changes on the kinematic and compliant parameters.
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