Analysis And Evaluation On The Operation Track Of Bus Independent Stop

With the continuous development of bus assistant driving technology,the requirement of intelligent level,convenience and safety of vehicles is increasing.Aiming at the problems of low utilization rate of berths,delay of bus in and out of the station and safety of passengers caused by the current free parking mode of buses,this paper explores the optimal path of optimizing vehicle parking based on the "one button" automatic bus stop system.In recent years,with the development of automatic driving technology,bus automatic stop system is becoming more and more mature.The driver enables the automatic stop option at the moment of arrival,and the bus will automatically complete the stop process according to the platform environment.In this paper,aiming at the optimization of bus stop trajectory,the nonlinear multi constraint optimization function(fmincon)in MATLAB software is used to simulate the bus stop trajectory of the harbor platform from the two cases of no car and car influence respectively by cubic spline interpolation,arctangent function and sigmoid function.First of all,consult the domestic and foreign literature about the types of bus stops,bus stop characteristics and track planning methods,determine the main idea of the study,in order to achieve the purpose of the optimal track of bus automatic stop.Secondly,in order to achieve a safe stop,environmental constraints and vehicle constraints should be considered.Environmental constraints are constraints analysis of obstacles in the process of stop;vehicle constraints,in order to ensure that the bus can run according to the planned path,the path curvature should be smaller or the curvature change slower.Then,in the path planning,the practicability of the planning path should be considered,that is,the constraints of vehicle steering angle and steering angle speed on the stopping path.Finally,a multi constraint equation is established to integrate platform structure and vehicle dynamics.Through the simulation of the bay bus platform with MATLAB software,only the trajectory planning method is changed when other parameters are consistent.The simulation results show that: under the influence of no vehicle in the station,the stop trajectory generated by three methods can get continuous curvature and meet the stop requirements of the bus,and can plan the bus stop trajectory in real time.Based on the comparison and analysis of the structural curve of the bay platform,it is concluded that the average potential difference of the approach station trajectory curve of arctangent function planning is 2.13 far less than that of the sigmoid planning and the cubic spline interpolation planning,which is 6.16% and 3.64% respectively.Under the influence of the vehicles in the station,the three methods are also used to generate the running track that meets the requirements of the bus stop Track curve,and use the track curve of harbor platform and three track curves for comparative analysis to choose a more suitable track curve;comparative analysis shows that the average potential difference of the path curve of arctangent function planning is 2.15 far less than the average potential difference of the path curve of sigmoid planning 2.63 and the average potential difference of the path curve of cubic spline interpolation planning 2.52.Therefore,the analysis of the track curve of the two situations in the station shows that the track curve based on arctangent function planning is more consistent with the platform structure,which makes it convenient for passengers to get on and off the bus when the bus stops,has high reliability and reduces the delay of getting in and out of the station.