Optimum design of working device of wheel loader

Some performances of ZL50 wheel loader do not meet the requirements, like delivering ratio, translation feature in lifting and automatic reset of the bucket. An optimal strategy for working device is adopted based on a virtual prototype in ADAMS. There are total 22 design variables which are 9 points' (x, y) coordinates of the reverse six-bar linkage and two hydraulic cylinders' extend and retract length in their axial direction. The simulation is focused on the affect of design variables on the performances of working device. Four different combinations of design variables are selected in optimization based on their sensitivity on the optimum objectives. They are “All Parameters”, “Base on Sensitivity”, “Bucket Unchanged” and “Bucket and Lift Arm Unchanged”. Some robust optimal solutions with multi constraints are obtained. All the constraints are given some margin. The optimum results show that three end points of the rocker arm and the joint point of tilt cylinder on the frame play an important role in optimizing the performance of the structure. After comparison, the scheme “Base on Sensitivity” can get the optimal solution with relatively fewer variables. It optimizes the delivering ratio from 0.314 to 0.450, the translation feature in lifting from 24.6° to 12.3°, the automatic reset of the bucket from 23.7° to 2.5°. The improvement of the performances after optimum design is obvious.