Target cascading methodology is proposed as an efficient approach to the design optimization of the geometry of a double-wishbone suspension system of an off-road vehicle. The geometric setting of the suspension plays an important role on its performance, as well as on the interactions with other design domains of the overall system. In order to organize the complexity of this system, two types of hierarchies are established: a system hierarchy and a model hierarchy.
For the system-based hierarchical organization, four levels were identified to express the suspension design problem in an overall vehicle design context: a super-system at the top level, two system design levels at the second and third hierarchical levels, and a components level at the lowest level.
The model-based hierarchical organization considers four analysis models to investigate the suspension behavior: a steering DOF constrained kinematic model, a longitudinal, a handling and a ride dynamics model.
In the present work, the nature of the interactions between the dynamic models and the geometric design variables is analyzed. Based on these interactions, the flow of geometric information between models is identified and a hierarchical organization of the dynamics models is proposed.
The proposed methodology is applied to the design and optimization of the suspension geometry of a hybrid off-road vehicle. In this application the advantages of a deeper knowledge on the problem nature are shown, as more flexibility is gained in the decision making process when special geometric interactions and restrictions must be considered.