Study And Analysis Of Dynamic Roll Stability Of Articulated Loader

As the most widely used model in construction machinery,the structure,load and center of mass of wheel loader are variable,and wheel loader is often used in the harsh working environment with complex and changeable road conditions.The above factors lead to poor lateral stability of wheel loaders,especially when driving in a straight line and encountering obstacles,it is very easy to overturn accidents.Based on this,this paper focuses on the roll instability mechanism of loader in straight obstacle crossing condition,constructs a reasonable roll stability index,and puts forward an anti roll control strategy based on active braking,active steering and working device attitude adjustment.The specific work is as follows:On the basis of reviewing the development history and status quo of vehicle roll stability research at home and abroad,the limitations of the current stability index and anti-roll control method on wheel loader are summarized.Taking the wheel loader system as the research object,considering the structural characteristics of the vehicle and the lateral instability process,the loader roll dynamic model based on ADAMS is established,and the correctness of the motion characteristics of the model and the accuracy of the center of mass position are verified by the actual vehicle.Based on the established dynamic model,the instability mechanism of wheel loader under straight obstacle crossing condition is analyzed,and the influence of different centroid height caused by slope pavement and working device on obstacle crossing instability of loader is also analyzed.The results show that whether the loader has roll instability under the straight-line obstacle crossing condition can be reflected by the roll angle speed.When the roll angle speed exceeds the critical threshold,the loader will roll over;The critical threshold is not only related to its own structure,but also affected by the angle of cross slope and the height of centroid,and shows a negative correlation law.To summarize the above analysis,the dynamic stability index suitable for the straight obstacle crossing condition of loader is established,which includes the dynamic information such as roll angle speed,cross slope angle and centroid height.The determination of vehicle centroid height affected by working device and load prediction based on neural network are studied.Based on the study of the instability mechanism and instability index of straight obstacle crossing of loader,the effects of active braking,active steering and attitude adjustment of working device on vehicle stability after obstacle crossing and instability of loader are analyzed respectively,and the control effects of each control method are comprehensively considered,he joint anti roll control method of "active braking,active steering and attitude adjustment of working device" is proposed.The effectiveness of the joint control strategy is verified by joint simulation,and the feasibility of the control strategy is verified by real vehicle test.To sum up,this paper establishes a roll multi-body dynamic model for comprehensively analyzing the straight obstacle crossing condition of the loader,constructs the dynamic stability index suitable for this condition on the basis of the simulation results,then puts forward the joint anti roll control strategy,and carries out the joint simulation and real vehicle test of the control strategy,which proves the effectiveness and enforceability of the control strategy.The study of this paper has certain significance for the development of active anti tipping safety technology of wheel loader.