Manipulation Stability And Control Of Trailer

Tractor trailer is composed of tractor and trailer.It has a lot of advantages.First,it can carry a lot of heavy goods.Secondly,its efficiency is very high.The most important of all,it costs little mo ney.Due to the movement of tractor and trailer is mutual coupling.There will be a lot of unstable phenomenon in the transport process,such as serpentine, upsetting, folding,whipping. Therefore,it is very necessary for us to improve the stability of tractor trailer。On the basis of research and the evaluating indicator at home and abroad.We determined the handling stability evaluation project of tractor trailer and the corresponding evaluating indicator. Then we considered the yaw movement and lateral movement of the tractor and trailer and established the four degrees of freedom mathematical model of full tractor trailer.We achieved open loop simulation.We reaearched the influence that the parameters of tractor trailer has caused on the stability.Then, through the research on the simplified mathematical model of the whole car,we analyzed the reason of the trailer swaying.According to the stability theory of dynamic system, we got the relationship between the size of the damping ratio and the stability of the system. Finally,We analyzed the stability of braking.And we established model which tractor rear wheels has been proportional controlled.Through selecting four different proportional coefficient,we got advantages and disadvantages of front and rear wheels with phase shift and reverse turning. Based on the theory of LQR,we controlled front wheel of trailer by optimal LQR theory,the results shows the running tragectory and stability has improved substantially.Driver-vehicle-road closed loop system is an important part of the handling stability. Combing the pilot,tractor trailer,road as a whole system is very rigorous. First we established the serpentine road and lane change test.Building the single point preview model.In order to improve the stability of the trailer,we invented the trailer wheel steering control rate.At different speed,we obeserved the dynamic response of tactor trailer which has been controlled and not been controlled.