| In recent years,with the increase in car ownership,the problem of traffic congestion has become increasingly prominent,and the need to alleviate traffic pressure has become more urgent.Vehicle queues can not only effectively relieve traffic pressure,improve road traffic capacity,reduce traffic accidents,but also reduce fuel consumption and environmental pollution.The main contents of this article are as follows:(1)First,the characteristics and advantages of the Internet of Vehicles technology system are introduced.On the basis of this,the vehicle-to-vehicle communication technology is analyzed.Based on the Vehicle-to-Vehicle technology,six communication topologies for vehicle queues are designed.Under the definition of vehicle queue stability,local stability,queue stability,traffic flow stability,and the relationship between the three are discussed.Finally,for the problem of queue spacing following,fixed spacing,fixed time interval and variable time are given Three distance following strategies are analyzed,and the influence of fixed distance and fixed time following strategies on the stability of the vehicle queue system is analyzed,which provides a basis for subsequent derivation and modeling.(2)In order to achieve the goal of tracking acceleration of the lower layer of the vehicle queue under different road conditions,a nonlinear longitudinal dynamic model of the vehicle was established,and the accuracy of the model was verified in Car Sim.Finally,for this model,based on sliding mode control,a lower queue controller with acceleration tracking and the same sliding rate of front and rear wheels as the control target is designed.The simulation results show that the controller can achieve the goal of the acceleration of the lower layer of the vehicle queue and the consistent sliding rate of the front and rear wheels.(3)Aiming at the vehicle queue system model based on Vehicle-to-Vehicle,an upper queue control strategy based on model prediction algorithm is proposed.First,the simplified nonlinear vehicle dynamics model is a second-order delay differential equation model,which can basically express the input and output response characteristics of vehicle dynamics.Then in the context of Vehicle-to-Vehicle technology,the state space model of the vehicle queue system is established.The model covers the state space model of the vehicle queue system when different communication topologies and the number of vehicles change.Finally,the model is based on the state space model.The predictive control method designs the upper controller of the vehicle queue.(4)The upper controller of the design was simulated and analyzed under a variety of typical complex working conditions,and the following effects of the vehicle queue system under the conditions of Vehicle-to-Vehicle and non-Vehicle-to-Vehicle front vehicle following,single vehicle following and multiple vehicle following,and communication interruption were compared.From the simulation results It can be seen that Vehicle-to-Vehicle is better than non-Vehicle-to-Vehicle preceding vehicle following,multi-vehicle following is better than single-vehicle following,and the interruption of the communication of adjacent preceding vehicles in multi-vehicle following mode will cause the instability of the queue system.In the above three comparative analysis,the queue following effect based on the Vehicle-to-Vehicle multi-vehicle following mode is the best.Therefore,in this mode,the nonlinear vehicle dynamic model established in Part 2 and the lower-level control based on the sliding mode control design are combined.And the third part of the vehicle queue upper controller based on model predictive control,constitute a queue coordination control system that considers vehicle dynamics,and the control system is simulated and analyzed under three different road conditions.The simulation results show that the control system It can achieve safe and stable driving of vehicle queues on low-adhesion roads and high-adhesion roads. |
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