Study On The Method Of Motion Preview Of Truck And Trailers

One of the important directions for the development of the current automobile industry is intelligence.The industry generally believes that commercial vehicle autonomous driving will take the lead in landing.With the continuous advancement of driverless technology,the commercialization of assisted driving technology for basic scenarios has been successful for single-body passenger vehicles,while trailer-mounted commercial vehicles have low driving stability and more complex motion processes.Autonomous driving technology still needs to explore and overcome some difficult problems.Among them,the comprehensive decision of the direction and speed of the trailer vehicle considering the driving stability is one of the difficult problems of the current automatic driving of the trailer vehicle.The aspect ratio of trailer-mounted vehicles is generally higher than that of monolithic vehicles,and the mass is larger,and the body units are connected by trailers,resulting in lower stability and easier driving of commercial vehicles than passenger vehicles.Instability phenomena such as rollover,folding,tail flick and sway appear.In addition,due to the trailer properties and relatively long body of the trailer vehicle,its motion process is more complicated and the sweeping area is larger.Therefore,the tractor and trailer should be comprehensively considered when planning its movement,so as to avoid the occurrence of excessive occupation of the lane during steering and rubbing of traffic participants.In view of the above problems,this paper takes the semi-trailer vehicle as the research subject.Based on the comprehensive decision-making model of the direction and speed of the research group that was only applicable to the single vehicle,we try to explore a method that considers the kinematic characteristics of the semi-trailer vehicle as mentioned above.The motion preview method is used to build a comprehensive decision-making model for direction and speed suitable for semi-trailer vehicles.Specifically,the following researches are mainly carried out:First,a motion preview strategy that comprehensively considers tractors and semi-trailers is explored.Firstly,the operating environment of the intelligent semi-trailer vehicle is analyzed in detail,and the reasonable assumptions of the modeling are put forward to ensure the real-time performance of the calculation.Then,based on the above assumptions,the kinematics model of the semi-trailer vehicle studied in this paper is built,which provides a theoretical basis for the trajectory estimation in the subsequent ego-vehicle motion preview process.Then,a comprehensive evaluation criterion of safety and legitimacy of tractor and semi-trailer is constructed,and it forms part of the motion preview strategy.Second,a preview strategy considering the driving stability of a semi-trailer is explored.Firstly,the method of determining the mobility of semi-trailer vehicle is explored,and the range of the combination of longitudinal acceleration and yaw angular velocity that semi-trailer vehicle can drive stably at different vehicle speeds is obtained through experiments,which provides stable driving control for the follow-up link of motion preview.amount of sampling space.Secondly,based on the analysis of the causes of rollover,folding,and tail swing,the driving stability of the semi-trailer is further improved by limiting the boundary values of the roll angle and the hinge angle in the motion preview period.The towed vehicle generates a highly stable reachable trajectory in real time.Finally,simulation experiments are carried out for typical scenarios.This study is based on the Truck Sim-Simulink co-simulation platform to conduct experiments.First,typical experimental scenarios such as dynamic obstacle avoidance,critical rollover,and curve deceleration and braking under lower road adhesion coefficients are set up.Then,the experimental scenarios are analyzed and discussed.The performance of the verified model,combined with the qualitative analysis of the experimental results,verifies the motion preview method for semi-trailer vehicles proposed in this paper.The degree of implementation and the guarantee of stability,legality,security and other goals.