Kinematics Analysis And Optimization Design For The Working Mechanism Of Wheel Loader

The working mechanism is an important part of a wheel loader.It is generally used to accomplish the shoveling,loading,lifting,and dumping tasks.Usually,the working mechanism is a Z-bar linkage.The design level can directly affect the functions of the working mechanism,and then further influence performance of the whole machine,including efficiency,working quality and the economic target.The dimensional design of the linkage directly affects the loader's service performance.Focusing on the multi-objective and multi-variable problems,this paper firstly establishes an accurate kinematic model of the Z-bar linkage with deduced expressions of the basic parameters.All the expressions can provide a mathematical foundation for the basic kinematics characteristics of the Z-bar linkage.After that,the author investigates the performance indexes including mechanism transmission ratio,lifting stationary,dumping angle in any position,bucket flat setting,maximum dumping height,minimum dumping clearance,dig force,working time and extreme transmission angle,etc.Existence conditions and performance indexes of the Z-bar linkage mechanism are consider comprehensively based on the parameterized kinematic model to establish a universal optimization model.With the MATLAB software and the complex optimum algorithm,the general optimization program is compiled.A case study with two optimization schemes as “full variables design” and “partial variables design” is conducted based on the actual engineering requirements.Analysis and optimization are conducted against the working mechanism of a certain loader,and the simulation results show that both schemes are better than the original one.The parameterized kinematic model,multi-objective optimization model and optimization schemes in this paper are of importance in generating user requirements oriented linkage design schemes with enough consideration and optimization of multiple performance indexes.