Optimal kinematic design of a multi-link steering system for a bus independent suspension: An application of response surface methodology
Keywords:Ackermann steering, central composite design (CCD), Design of Experiments (DOE), Independent front suspension (IFS), Maximum Steering Error (MSE), Multi-link steering system, Optimisation, Regression, Response surface methodology (RSM)
A response surface-based design application to obtain an optimum multi-link steering mechanism is presented. Design problem is essentially established on two main goals: minimum deviation of toe angle during the wheel travel and optimum steering error during the steering angle range of the wheel. In the first stage, a complete multibody model of the suspension system including the steering mechanism was composed by using MSC.Adams software. In order to identify the most effective parameters among the tie rod co-ordinates on toe angle deviation, a Full Factorial Design-based Design Sensitivity Analysis (DSA) was carried out via Adams/Insight multi-objective optimisation tool. Central Composite Design (CCD) was also implemented to find out the optimum position of the tie rod. In the final stage, optimum hard-point positions of the steering mechanism were searched by a combination of sweep study (SS) and CCD to provide the minimum deviation of Ackermann error. The optimisation results show that it is possible to reduce the maximum steering error (MSE) of the system up to 89.6% in comparison with the parallel arm base mechanism by using the proposed methodology.