Research On Economic Speed Planning For PHEV Platoon

With energy shortages,road congestion and traffic accidents becoming more and more prominent,countries around the world are actively looking for solutions,with much of the research focusing on Plug-in Hybrid Electric Vehicle(PHEV)vehicle fleets to address these issues.On the one hand,PHEVs can improve fuel economy by combining the advantages of conventional fuel vehicles and pure trams,while on the other hand,vehicle queue control technology can improve road utilisation and reduce traffic accidents.However,PHEV vehicle queues still have the problem of increasing the total energy consumption of the queue due to different initial states and driving at unreasonable speeds.This paper selects PHEV vehicle queues as the research object and conducts a speed planning study to reduce the total energy consumption of the vehicle queue by optimising the overall economy of the queue.The main research elements include:Translated with www.Deep L.com/Translator(free version)(1)Analysis of the structural characteristics and working model of a single-vehicle PHEV,establishment of key components and overall vehicle dynamics models,and formulation of a CD/CS(Charge of Depleting/Charge of Sustaining,CD/CS)energy management strategy for driverless vehicles considering mechanical braking torque distribution,with WLTC(The model and energy management strategy are simulated and analyzed to verify the rationality and effectiveness of the model and strategy,using the Worldwide Light-duty Test Cycle(WLTC)and deceleration test conditions as inputs.(2)The single vehicle longitudinal dynamics model is used as the vehicle queue node,the variable air resistance coefficient is introduced in the node dynamics model,the information flow topology of the following strategy is selected,on this basis,a dual condition following distance control strategy is proposed,a distributed nonlinear controller that is compatible with multiple following distance control strategies is designed,a 5 vehicle queue is constructed,and the simulation is carried out with the timed distance following strategy Compared with the timed distance strategy,the dualconditions strategy reduces the air resistance coefficient by 25%,27%,30%,38% and20% respectively,air resistance reduced by 26%,34%,34%,37%,and 22%respectively,the speed error is reduced by 22% on average.(3)In response to the problem that the subsequent vehicle queueing algorithm is computationally heavy and cannot be online in real time,a boundary speed planning study is proposed to reduce the computational load of the subsequent algorithm while improving the operation rate of the vehicle queue.First of all,we analyze the type of vehicle speed curve,synthesize the characteristics of each curve,and select the 7-segment S-type speed curve as the research object.On this basis,the mathematical model of this speed curve is established,the acceleration parameters are selected through theory,the parameters required for the impact degree calculation formula are collected through real vehicle road experiments,and finally the boundary vehicle speed curve required for the study is planned.(4)For the problem that the total energy consumption of the PHEV vehicle queue interacts with the driving time,a multi-objective optimization index function is constructed,then,a dynamic programming(DP)based PHEV vehicle queue economy speed planning algorithm is constructed and the problem is solved,finally,the upper and lower speed limits of the boundary speed planning are solved for the time weight coefficients The range of time weighting coefficients is then compared with the speed upper and lower bounds of the boundary speed planning,the travel time and the total energy consumption of the queue are compared,and the time weighting coefficients that meet the requirements are selected and compared with the simulation results without time cost;based on the selected time weighting coefficients,the parameters of the algorithm,such as state and control variables,are analysed to verify the feasibility of the algorithm;the economic vehicle speed corresponding to the best time weighting coefficients is input into the algorithm-free PHEV vehicle queue,and In comparison with the above economical vehicle speed algorithm,the economical vehicle speed controlled by the DP algorithm reduces the total energy cost of the PHEV queue by20.25%,demonstrating the potential of the algorithm to save energy.