Research On Heacy Duty Vehicle Chassis Anti-rollover Collaborative Control

With the rapid development of Chinese highway,as a kind of transportation vehicles,heavy duty vehicles account a large part of road vehicles.As heavy duty vehicles have traits with high gravity center,heavy mass and loads,and narrow wheel space in comparison with other kinds of vehicles.Besides that,due to the complexity of heavy vehicles traffic and driving conditions.Thus the stability of heavy duty vehicles,especially the anti-rollover performance with high speed is placed high value.According to the reasons mentioned above,heavy duty vehicle is selected as research object.In this research,firstly review domestic and abroad relevant researches on heavy duty vehicles in recent years,then learn and analyze the roll stability mechanism for heavy-duty vehicles.Based on traditional three degree of freedom heavy duty vehicles simple rollover model,the research concerns about vehicle body,four suspensions and four tires vertical dynamic system,then according that,establish eight degree of freedom vehicle model adding with vertical dynamic system as the controlled object based on heavy duty vehicles.After that,according to three degree of freedom model,the research also establishes a warning system about heavy duty vehicles to warning drivers whether there is rollover danger after conducting steering wheels.In this rollover warning system,some vehicle state parameters can be achieved by sensors installed on vehicles,but still there are several state parameters can't be measured.Thus this research proposes a state parameters predictive algorithm using Extended Kalman Filter estimating method of the heavy duty vehicles,after achieving the measured and estimated vehicle state parameters,use the data as input of rollover warning system to calculate load transferring ratio(LTR)which is put as the rollover index of heavy duty vehicles.Based on load transferring ratio,the warning system reckons and outputs what is the time to rollover for heavy duty vehicles,at last,use MATLAB to simulate the three degree of freedom heavy duty vehicles estimated state parameters model and the rollover warning system for heavy duty vehicles with different front wheels steering angle and different driving velocity in different conditions.Then according to the rollover warning system outputting results,verdict whether this heavy duty vehicle is facing to rollover danger and warn the driver to modify the conduction just the like steering the wheel or decelerate the vehicle's velocity.At last,a kind of collaborative control strategy which contains semi-active suspension damper adjusting algorithm and active anti-roll bar fuzzy-PID control algorithm is designed.When heavy duty vehicles do not have rollover danger,the semi-active suspension damper adjusting algorithm is used to improve vehicles' stability in driving condition;when the heavy duty vehicles have rollover danger or are facing to rollover,the designed collaborative control strategy is started to prevent vehicles to rollover in time and to some extent enhance the safety and stability of heavy duty vehicles in driving condition.Finally this collaborative control strategy's efficiency is proved by simulating and testing in Matlab with different conditions,according to analyzing the results,collaborative control system can be considered enhance driving heavy duty vehicles' safety and stability.