Research On Roll Stability Of Wheel Loader

The topic comes from the Open Fund of the National Engineering Laboratory of Highway Maintenance Equipment,“Study on the Tilting and Unstable Stability of Wheel Loaders under Complex Road Conditions”(310825161104).The wheel loader has the advantages of fast operation speed,high efficiency,good maneuverability and light operation.It is often used in engineering construction for the harsh environment with complicated road conditions such as mining,road construction and house construction.However,the working conditions of the wheel loader are complicated and versatile,which may cause the vehicle to become unstable and roll over during the driving process,thereby causing significant loss of life and property.In this paper,the wheel loader system is taken as the research object.For the problem of instability tilting and control optimization,considering the factors of working device,suspension system,front and rear body articulation,the nine-degree-of-freedom roll dynamics model is established and the characterization equations of roll stability under the action of dynamic lateral transfer load is proposed.The influence of different parameters and typical test conditions on the roll stability of wheel loader is analyzed.The control strategy is improved to optimize the roll stability of wheel loader and improve vehicle safety.The main contents of this paper are as follows:(1)Considering the working device,front and rear body articulation and suspension system,the wheel loader roll dynamics model is established based on the Newton-Euler method.The model includes 16 degrees of freedom for front and rear body longitudinal vibration,lateral vibration,vertical vibration,pitch,roll,yaw and four non-spring loaded masses.The model is solved by variable step method and compared with the virtual prototype.The validity of the model is verified and it can be used as a tool for the analysis of roll stability of wheel loaders.(2)The characterization equation of roll stability under dynamic lateral transfer load is proposed,and the dynamic model is used to analyze the roll stability under different parameters.The main parameters include driving speed,lateral slope angle,centroid height,wheel spacing,the sum of the distance from front and rear body to articulation point,boom lifting angle and suspension system.The results show that vehicle speed,lateral slope angle,centroid height and suspension system have great influence on vehicle roll stability,which provides parameters optimization basis for wheel loader roll stability.(3)The simulation model of typical working conditions of wheel loader is constructed,the roll stability tests under heavy and no-load conditions are completed,and the results are compared and analyzed.The results show that the roll stability of wheeled loader is poor under no-load condition,and the possibility of unstable rollover of vehicle is high.Under double line-shifting test,the evaluation indexes of roll angle,lateral acceleration and roll stability of wheeled loader are too large to cause unstable rollover.(4)Based on the analysis results of the wheel loader’s roll stability,the direct yaw moment control method is used to control the roll stability of the wheel loader.The research results show that the direct yaw moment control method can effectively improve the roll stability during the running of the vehicle,and provides an effective control method for the wheel loader steering under complicated road conditions.