Autopilotautomatic-manual Driving Based On Cellular Automaton Research On Characteristics Of Mixed Traffic Flow

With the development of autonomous driving technology,autonomous driving vehicles have become a reality.It is foreseeable that the proportion of autonomous vehicles will gradually increase in the near future.The mixing of autonomous vehicles will definitely have a huge impact on the operation of highway traffic flow,so It is very important to study the traffic flow characteristics of the mixed automatic-manual driving traffic flow on the expressway.The purpose of this paper is to study the characteristics of automatic-manual driving mixed traffic flow.With the help of cellular automaton theory,a two-lane model of expressway automatic-manual driving mixed traffic flow is constructed,and then Matlab software is used to simulate and simulate automatic-manual driving.The operation characteristics and safety characteristics of mixed traffic flow were studied.The main work of this article is as follows:?1?After analyzing the operating characteristics of automatic driving vehicles and the mechanism of lane change during mixed traffic flow operation,the calculation method of the safe speed of manual driving vehicles was revised on the basis of the improved TSM model,and more flexible and flexible Change lane rules and establish a new automatic-manual mixed traffic flow model.On this basis,the effects of different expected headway distances,different mixed traffic ratios,and different lane changing probabilities on the traffic flow of autonomous vehicles are studied.The simulation results show that under the condition of a certain proportion of autonomous vehicles,the smaller the expected headway of the autonomous vehicle,the greater the road capacity.For example,when the ratio of the autonomous vehicle P_auto=1,the expected distance of the autonomous vehicle The maximum traffic capacity of the road with T_acc=1.3s is about 36%higher than that when the expected headway of the self-driving vehicle is T_acc=1.5s.Under the condition that the expected distance of the head of the self-driving vehicle is fixed,the higher the ratio of the self-driving vehicles,the greater the road capacity.For example,when the expected head distance of the self-driving vehicle is 1.3s,the proportion of the self-driving vehicle Pauto=1 The road capacity is improved by about 87%compared with the proportion of autonomous vehicles P_auto=0.Different expected headway time intervals have different extents to improve road capacity;the mixing of self-driving vehicles in free-flow phase has little effect on traffic flow,while the introduction of self-driving vehicles in congested phase can significantly improve traffic flow Congestion situation,and the higher the proportion of self-driving vehicles,the more significant the improvement;at the same time,the different lane change probability has a weaker effect on mixed traffic flow.?2?The operation safety of mixed traffic flow with the participation of self-driving vehicles has always been a concern of scholars and is also a research hotspot of mixed traffic flow at this stage.Introduce safety evaluation indicators such as the standard deviation of the average speed of traffic flow,the standard deviation of the following distance,the number of lane changes per kilometer per hour,and the collision time to evaluate the safety of mixed traffic flow.The simulation results show that when the expected headway of the self-driving vehicle is T_acc=1.5s,under a certain density,the standard deviation of the speed becomes smaller as the proportion of the self-driving vehicle increases,indicating that the introduction of the self-driving vehicle can be effective Reducing the speed fluctuations of traffic flow promotes the stable operation of mixed traffic,and when the expected distance of the front of the self-driving vehicle is T_acc=1.3s or 1.1s,the increase of autonomous vehicles can delay the change trend of the speed difference of mixed traffic;At the same time,the mixing of autonomous vehicles can significantly reduce the number of lane changes and the higher the proportion of autonomous vehicles,the greater the reduction in the number of lane changes;from the collision time,it can be seen that the mixing of autonomous vehicles can continuously reduce the traffic flow.Potentially dangerous.