Cooperative control method for vehicle confluence track in highway confluence area under mixed traffic flow

Abstract

The invention relates to the technical field of vehicle confluence under mixed traffic flow, and discloses a cooperative control method for a vehicle confluence track in an expressway confluence area under mixed traffic flow, which comprises the following steps of: dividing the expressway confluence area into a control area and a merging area; determining a main road convergence feasible gap according to vehicle types and vehicle states in front of and behind the gap in the control area and a feasible gap cooperative adjustment range between the safe distance and different vehicle gaps; according to the main road convergence feasible gap and the time when the vehicle arrives at the tail end of the control area, a trajectory optimization model is established with the minimum vehicle running energy consumption as the target, all possible convergence main road gaps are traversed through the trajectory optimization model, and the feasible gap with the minimum energy consumption is selected as the convergence gap for vehicle trajectory collaborative optimization control. According to the method, the cooperative control of the confluence sequence and the vehicle running track planning during confluence of vehicles in the confluence area is realized, and the running efficiency is improved and the comprehensive energy consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle merging under mixed traffic flow, and in particular to a method for collaboratively controlling vehicle merging trajectories in a merging area of ​​a highway under mixed traffic flow. Background Art

[0002] The entrance ramp merging area of ​​a highway is usually a key bottleneck in the traffic flow, which not only causes serious traffic congestion, but also may cause the congestion to spread upstream and trigger new traffic accidents. Early solutions mainly rely on traditional ramp signal control and traffic flow control strategies. These methods usually assume that all vehicles will uniformly comply with the same control measures, but this ignores the subtle changes in traffic flow, so the improvement effect is limited. Intelligent Connected Vehicles (ICV) technology is seen as an effective way to alleviate these problems. However, ICVs and traditional human-driven vehicles (HDV) will coexist for a long time in the future, forming a mixed traffic flow. Therefore, it is particularly important to study the highway entrance ramp merging strategy in this mixed traffic flow environment.

[0003] The existing vehicle merging solutions under mixed traffic flow mainly have the following problems:

[0004] (1) Previous studies on highway on-ramp merging under the background of intelligent networking mainly focused on the ICV merging trajectory method under the pure networking background, lacking the coordinated control of ramp and main road vehicles, and lacking the coordinated consideration of the dynamic interaction between merging sequence selection and vehicle operation trajectory planning.

[0005] (2) Previous studies on merging control for mixed traffic flows mainly performed static optimization of vehicle trajectories based on the gap between ramp vehicles merging into the main road, without considering the dynamic interaction between merging sequence selection and vehicle trajectory planning.

[0006] (3) Previous optimization-based vehicle merging methods for mixed traffic flows mostly plan vehicle trajectories to ensure that ramp vehicles can merge according to a specified merging sequence, but fail to consider the impact of vehicle acceleration changes on vehicle energy consumption. Summary of the invention

[0007] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method for collaboratively controlling vehicle merging trajectories in a merging area of ​​a highway under mixed traffic flow.

[0008] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0009] A method for collaboratively controlling vehicle merging trajectories in a merging area of ​​a highway under mixed traffic flow comprises the following steps:

[0010] The expressway merging area is divided into a control area and a merging area. The feasible gap for merging into the main road is determined based on the vehicle types and vehicle status before and after the gap in the control area, as well as the coordinated adjustment range of the safe distance and the feasible gap between different vehicle gaps.

[0011] According to the feasible gap for merging into the main road and the time when the vehicle arrives at the end of the control area, a trajectory optimization model is established with the goal of minimizing the vehicle operation energy consumption. The trajectory optimization model is used to traverse all possible main road gaps for merging, and the feasible gap with the minimum energy consumption is selected as the merging gap for collaborative optimization control of vehicle trajectories.

[0012] The present invention has the following beneficial effects:

[0013] (1) Under mixed traffic flow conditions, the existing main line gap state passively selects the merging sequence based on the first-in-first-out principle and then performs trajectory planning, lacking active regulation of the main line gap. The present invention proposes a possible merging gap search method that takes vehicle characteristics into consideration, which not only determines the existing feasible gap that can meet the requirements of safe merging, but also calibrates the potential feasible gap that can meet the requirements of safe merging through adjustment, thereby determining the possible merging gap.

[0014] (2) Most of the methods for controlling vehicle merging in highway merging areas plan vehicle trajectories with the goal of ensuring that ramp vehicles can merge in accordance with the specified merging sequence, but fail to consider the impact of the vehicle acceleration change process on vehicle energy consumption. In this regard, the present invention considers the interactive influence relationship between the merging sequence and vehicle operation trajectory planning, and, on the premise of ensuring that ramp vehicles merge into the main line safely and efficiently, plans trajectories and adjusts gaps for ramp vehicles and all vehicles before and after the possible merging gaps with the goal of minimizing vehicle operation energy consumption, and then selects the feasible gap with the minimum energy consumption as the merging gap, thereby achieving coordinated control of the merging sequence and vehicle operation trajectory planning when vehicles merge in the merging area to improve operation efficiency and reduce comprehensive energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A flow chart of a method for collaboratively controlling vehicle merging trajectories in a merging area of ​​a highway under mixed traffic flow;

[0016] Figure 2 This is a schematic diagram of the vehicle merging scene on the entrance ramp of a highway under mixed traffic flow;

[0017] Figure 3 It is a flow chart of a feasible gap determination method;

[0018] Figure 4 Optimize the flow chart of the vehicle merging sequence and trajectory planning in the control area;

[0019] Figure 5 is the ramp ICV penetration rate P when there is no control strategy ρ = 0.6 and road density P I = 0.4 test result diagram;

[0020] Figure 6 is the ramp ICV penetration rate P when there is no control strategy ρ = 0.6 and road density P I = 0.8 test result diagram;

[0021] Figure 7 is the ramp ICV penetration rate P when there is no control strategy ρ = 0.9 and road density P I = 0.4 test result diagram;

[0022] Figure 8 is the ramp ICV penetration rate P when there is no control strategy ρ = 0.9 and road density P I = 0.8 test result diagram;

[0023] Fig. 9 The ramp ICV penetration rate P is the vehicle dynamic cooperative merging control strategy ρ = 0.6 and road density P I = 0.4 test result diagram;

[0024] Fig.10 The ramp ICV penetration rate P is the vehicle dynamic cooperative merging control strategy ρ = 0.6 and road density P I = 0.8 test result diagram;

[0025] Fig.11 The ramp ICV penetration rate P is the vehicle dynamic cooperative merging control strategy ρ = 0.9 and road density P I = 0.4 test result diagram;

[0026] Fig.12 The ramp ICV penetration rate P is the vehicle dynamic cooperative merging control strategy ρ = 0.9 and road density P I Schematic diagram of the test results when =0.8. DETAILED DESCRIPTION

[0027] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0028] The present invention proposes a method for collaboratively controlling vehicle merging trajectories in a merging area of ​​a highway under mixed traffic flow. Firstly, the vehicle operation characteristics of ICVs and HDVs are considered in the control area to determine all possible main road gaps for ramp vehicles to merge into. Then, the interactive influence relationship between the merging sequence and the vehicle operation trajectory planning is considered, and a trajectory optimization model is established with the goal of minimizing vehicle operation energy consumption, and ramp and main road vehicles are planned. Finally, the established trajectory optimization model is used to traverse all possible main road gaps for merging into, and the feasible gap with the minimum energy consumption is selected as the merging gap, thereby realizing collaborative optimization control of vehicles with minimum energy consumption.

[0029] Reference Figure 1 and Figure 4 , an embodiment of the present invention provides a method for collaboratively controlling vehicle merging trajectories in a merging area of ​​a highway under mixed traffic flow, comprising the following steps S1 to S2:

[0030] S1. Divide the merging area of ​​the expressway into a control area and a merging area, and determine the feasible gap for merging into the main road based on the vehicle types and vehicle status before and after the gap in the control area, as well as the coordinated adjustment range of the safe distance and the feasible gap between different vehicle gaps;

[0031] In an optional embodiment of the present invention, the application scenario of this embodiment is a highway merging area under an intelligent networked mixed traffic flow composed of ICVs and HDVs. Figure 3 As shown in the figure, the ramp is connected to the main line through a parallel acceleration lane. During the operation of the vehicle, the ICV can send instructions to the vehicle automatically in real time through the roadside unit and its own perception information, such as collecting vehicle speed, acceleration, and position, while the ICV guides based on the information of the preceding vehicle to adjust the vehicle status, but there is a possibility of not obeying the guidance. This paper divides the merging area into an upstream control area and a vehicle merging area. In order to enable ramp vehicles to merge into the main line efficiently and safely, the upstream control area searches for merging gaps, and selects the merging gaps based on the principle of minimum energy consumption. The selected ramp vehicles and the vehicles before and after the expected merging gaps are called cooperative vehicle groups. Considering the uncertainty of HDV, real-time vehicle trajectory planning or guidance is performed for the ramp vehicles and the vehicles before and after the expected merging gaps of the main line, so that the ramp vehicles can merge into the main road safely and efficiently in the merging area.

[0032] This example first assumes that:

[0033] (1) Only the rightmost lane of the highway is considered for merging on the ramp, and the ramp has only one lane, such as Figure 2 shown.

[0034] (2) The vehicles in the merging area are composed of ICVs and HDVs. The IDM following model is used between HDVs, the ACC following model is used between ICVs and HDVs, and the CACC following model is used between ICVs and ICVs. It is assumed that ICVs can obtain the speed, acceleration, position and other information of surrounding vehicles in real time and can execute control commands without delay. HDVs use the IDM following model. In this state, the driving state of the HDV cannot be fully controlled, but its trajectory is predictable in a short time (such as within a few seconds).

[0035] (3) Only the longitudinal trajectory is considered. It is assumed that the ICV and HDV meet the lane changing conditions, that is, the lane changing is completed instantly. The lane changing model adopts the LC2013 model.

[0036] In order to ensure that ramp vehicles can merge into the main line safely and efficiently in the merging area, this embodiment needs to search for the lane-changing gaps for ramp vehicles merging into the main line vehicles in advance in the upstream control area, so as to determine the merging sequence and vehicle operation trajectory. When determining the main line merging gap, if only the existing gaps that meet the merging gaps are selected, the feasible gaps left by the coordinated regulation of gap vehicles may be ignored. In this regard, this embodiment proposes a method for searching for merging gaps. According to the vehicle state and considering the safety distance, the feasible gap collaborative adjustment range between different vehicle gaps is analyzed to determine the main road merging feasible gap that meets the safe lane changing conditions. It includes the vehicle gaps that meet the safety distance in the current state and the potential vehicle gaps that meet the safety distance after vehicle regulation. Here, the ramp vehicle selection vehicle gap is defined as i∈I col , I col The set of all vehicle gaps on the main road from the initial to the end position of the control area, and the set of feasible gaps that meet the conditions for safe lane change are I F , set the initial

[0037] This embodiment determines the feasible gap for merging into the main road according to the vehicle type and vehicle status before and after the gap in the control area, as well as the safe distance and the feasible gap coordinated adjustment range between different vehicle gaps, including:

[0038] Starting from the first vehicle on the main line of the main road control area, calculate the distance between the vehicles before and after the main road control area gap;

[0039] Determine whether the distance between the vehicles before and after the gap is greater than or equal to the minimum safe gap; if so, treat the gap as a main road and merge into a feasible gap; otherwise, adjust before the end point of the main road control area according to the type of vehicles before and after the gap to meet the requirement of a feasible gap.

[0040] Among them, the adjustment before the end point of the main road control area according to the vehicle types before and after the gap to achieve a feasible gap includes:

[0041] When both the front and rear vehicles are intelligent connected vehicles, the rear vehicle is decelerated at a comfortable deceleration and the front vehicle is driven at a constant speed to determine whether the minimum safety gap is met when the front vehicle reaches the end point of the main road control area; if so, the adjusted gap is used as a main road to merge into a feasible gap; otherwise, the front vehicle is accelerated at the maximum safety acceleration and the rear vehicle is driven at a constant speed to determine whether the minimum safety gap is met when the front vehicle reaches the end point of the main road control area; if so, the adjusted gap is used as a main road to merge into a feasible gap; otherwise, the rear vehicle is decelerated at a comfortable deceleration and the front vehicle is accelerated at the maximum safety acceleration to determine whether the minimum safety gap is met when the front vehicle reaches the end of the main road control area; if so, the adjusted gap is used as a main road to merge into a feasible gap; otherwise, the gap is an infeasible gap;

[0042] When the front and rear vehicles are intelligent network-connected vehicles and manually driven vehicles, the rear vehicle is decelerated at a comfortable deceleration and the front vehicle is driven at a constant speed to determine whether the minimum safety gap is met when the front vehicle reaches the end point of the main road control area; if so, the adjusted gap is regarded as a feasible gap that merges into the main road; otherwise, the gap is an infeasible gap;

[0043] When the front and rear vehicles are manually driven vehicles and intelligent networked vehicles, the front vehicle is accelerated at the maximum safe acceleration and the rear vehicle is driven at a constant speed to determine whether the minimum safe gap is met when the front vehicle reaches the end point of the main road control area; if so, the adjusted gap is regarded as a feasible gap that merges into the main road; otherwise, the gap is an infeasible gap;

[0044] When both the front and rear vehicles are manually driven vehicles, the rear vehicle is decelerated at a comfortable deceleration and the front vehicle is driven at a constant speed to determine whether the minimum safety gap is met when the front vehicle reaches the end point of the main road control area; if so, the adjusted gap is regarded as a feasible gap merging into the main road; otherwise, the gap is an infeasible gap.

[0045] In this embodiment, the calculation is first performed from the first vehicle on the main line of the main road control area to the back to see whether a feasible gap can be adjusted before the end of the main road control area. The feasible gap is divided into a gap greater than the minimum safe merging distance S safe The gap that can be adjusted to become a feasible gap before the end of the main road control area. safe The calculation method is:

[0046] g min_m =s0+τ·v mer +lv

[0047] S safe=2 g min_m

[0048] where g min_m v is the minimum safe distance between the ramp vehicle and the vehicles ahead and behind it when the ramp vehicle merges into the main road at the merging area, mer is the inflow speed of the merging point, s o is the static gap between vehicles, τ is the minimum safe headway, and lv is the vehicle length.

[0049] Then calculate the distance ΔX between the two vehicles A and B at time k in the main road control area before and after the gap i. i,AB,k , if it is greater than the minimum safe merging distance S safe , then the gap i is judged to be a feasible gap, I F =I F ∪i, corresponding to:

[0050] ΔX i,AB,k =X i,A,k -X i,B,k ≥S safe

[0051] If the requirement is not met, determine whether the gap can be adjusted before the end of the control zone to meet the requirement of a feasible gap. If so, add the gap i to the feasible gap set I. F middle, I F =I F ∪i.

[0052] Reference Figure 2 , the method for judging whether the main road vehicle gap is a feasible gap and its specific adjustment method are as follows:

[0053] (1) The rear vehicle-front vehicle is ICV-ICV: first adopt method 1. If a feasible gap cannot be generated, adopt method 2. If a feasible gap still cannot be generated, adopt method 3. If both methods cannot generate a feasible gap, the gap is considered to be a non-feasible gap.

[0054] (2) The rear vehicle-front vehicle is ICV-HDV: adopt method 1. If a feasible gap cannot be generated, the gap is considered to be infeasible.

[0055] (3) The rear vehicle-front vehicle is HDV-ICV: adopt method 2. If a feasible gap cannot be generated, the gap is considered to be infeasible.

[0056] (4) The rear vehicle-front vehicle is HDV-HDV: adopt method 1. If a feasible gap cannot be generated, the gap is considered to be infeasible.

[0057] In this embodiment, method 1 decelerates the rear vehicle at a comfortable deceleration and drives the front vehicle at a constant speed, and determines whether the minimum safety gap is met when the front vehicle reaches the end point of the main road control area, including:

[0058] According to the speed of the rear vehicle and the time it takes for the front vehicle to reach the end point of the main road control area at a constant speed, the speed of the rear vehicle until it decelerates until the end point of the main road control area is calculated;

[0059] Determine whether the speed of the following vehicle that has been decelerating until the end point of the main road control area is less than the minimum speed limit; if so, calculate the position of the following vehicle that has been decelerating until the end point of the main road control area; otherwise, calculate the position of the following vehicle that has been decelerating first and then driving at a constant speed in the operating period of the control area;

[0060] The distance between the front and rear vehicles is calculated based on the position of the rear vehicle when the front vehicle reaches the end point of the control area, and it is determined whether the distance between the front and rear vehicles meets the minimum safety gap. If so, the adjusted gap is used as a main road to merge into a feasible gap; otherwise, the adjustment fails.

[0061] In this embodiment, when the rear vehicle decelerates at a comfortable deceleration and the front vehicle travels at a constant speed, it is determined whether the minimum safety gap is met when the front vehicle reaches the end of the main road control area. Suppose that in the i-th gap, the front vehicle A travels at a constant speed to the end point position X of the control area. Col_end The duration is The rear vehicle B decelerates at a comfortable deceleration. The speed of the moment can be expressed as:

[0062]

[0063] where t k is the timestamp corresponding to the kth time step, v i,B (t k ) is the gap between the i-th and the rear vehicle B at t k Speed, a dec is the comfortable deceleration of the vehicle, v min is the minimum speed limit. At this time, if the rear vehicle B in the i-th gap continues to slow down until the end of the main road control area, the corresponding speed is When it is less than v min At this time, the rear vehicle B decelerates uniformly until it reaches the end of the control zone. Corresponding position It is expressed as:

[0064]

[0065] Where X i,B (t k ) is the position of vehicle B after the i-th gap at t0.

[0066] Otherwise, when the vehicle speed reaches the minimum speed limit before the end of the control area, the following vehicle B will first slow down and then maintain a constant speed. The position of the vehicle during the operation period in the control area is:

[0067]

[0068] When the current vehicle A reaches the end of the control area, calculate Distance between front and rear vehicles after time for:

[0069]

[0070] Determine the distance between front and rear vehicles Is it greater than the minimum safe merging distance S? safe If the minimum safe merging distance is not met, method 1 is not feasible.

[0071] In this embodiment, method 2 accelerates the front vehicle at the maximum safe acceleration and drives the rear vehicle at a constant speed, and determines whether the minimum safety gap is met when the front vehicle reaches the end point of the main road control area, including:

[0072] According to the time taken by the preceding vehicle of the preceding vehicle to reach the end point of the main road control area at a uniform speed from the initial point, the speed of the preceding vehicle when the preceding vehicle of the preceding vehicle reaches the end point of the main road control area is calculated;

[0073] Determine the speed of the preceding vehicle and calculate the distance traveled by the preceding vehicle after accelerating to the maximum speed, and determine whether the traveled distance is less than the distance between the preceding vehicle and the end point of the control area at the beginning of the gap; if so, calculate the time it takes for the preceding vehicle to reach the end point of the control area after uniformly accelerating to the maximum speed; otherwise, calculate the time it takes for the preceding vehicle to reach the end point of the control area after uniformly decelerating;

[0074] The distance between the front and rear vehicles is calculated based on the time when the front vehicle reaches the end point of the control area to determine whether the distance between the front and rear vehicles meets the minimum safety gap; if so, the adjusted gap is used as a main road to merge into the feasible gap; otherwise, the adjustment fails.

[0075] In this embodiment, when the leading vehicle corresponding to the control gap accelerates at the maximum safe acceleration and the following vehicle travels at a constant speed, it is determined whether the minimum safe merging distance is met before the leading vehicle reaches the end of the main road control area. Assume that the maximum speed at which the leading vehicle A can accelerate is v A_max , and its corresponding value range is v i,A (t k )≤v A_max ≤v max If the gap before the current vehicle A is a used gap, then the speed of the current vehicle A must be less than or equal to the speed of the vehicle A_F before the current vehicle. At this time, v A_max =v A_F If the previous gap of the preceding vehicle A corresponding to the control gap is not used, then the preceding vehicle A and the preceding vehicle A_F of the preceding vehicle only need to meet the minimum headway h when they arrive at the end of the main road control area. Suppose the time taken by the preceding vehicle A_F of the preceding vehicle in the i-th gap to reach the end of the control area at a uniform speed from the initial point for:

[0076]

[0077] Where L M is the total length of the control area.

[0078] Assume that the headway time T between the preceding vehicle A and the corresponding preceding vehicle A_F is AA_F , the maximum safe headway time must be maintained during operation in the control area, that is, T AA_F ≥h. The front vehicle A is Speed The calculation formula is:

[0079]

[0080] where a max The maximum possible acceleration is:

[0081] When vehicle A_F reaches the end of the main road control area, the speed of the front vehicle A is When its speed is less than v A_max hour The front vehicle A accelerates uniformly until it reaches the end of the main road control area. At the position corresponding to time t2 for:

[0082]

[0083] Otherwise, the front vehicle A accelerates to the maximum speed v A_max , then in uniform form, at the position corresponding to time t2 for:

[0084]

[0085] The front vehicle A accelerates to the maximum speed v A_max The distance traveled afterwards is ΔX i,A_v for:

[0086]

[0087] Let L M -X i,A (t k ) is the distance between the front vehicle A and the front vehicle A in the i-th gap at t k The distance from the end point of the control area, if ΔX A_v Less than L M -X i,A (t k ), that is, the front vehicle A accelerates to v A_max If the vehicle still fails to reach the end of the control zone after accelerating to v A_max Then the vehicle A in front of it drives at a constant speed until it reaches the end of the control area. At this time, the vehicle A in front of it accelerates uniformly to v A_maxThe time t1 after reaching the end point of the control area is:

[0088]

[0089] When otherwise if ΔX A_v Greater than L M -X A (t k ), the front vehicle A decelerates uniformly until it reaches the end of the control area, and the time it takes for the front vehicle A to reach the end of the control area is obtained. for:

[0090]

[0091] When the current vehicle A reaches the end of the control area, calculate The time is:

[0092]

[0093] The distance between the front and rear vehicles of the i-th gap Is it greater than the minimum safe merging distance S? safe , if the minimum safe merging distance is not met, method 2 is not feasible.

[0094] In this embodiment, method 3 decelerates the rear vehicle at a comfortable deceleration and accelerates the front vehicle at a maximum safe acceleration, and determines whether the minimum safety gap is met when the front vehicle reaches the main road control area point, including:

[0095] According to the time taken by the preceding vehicle of the preceding vehicle to reach the end point of the main road control area at a uniform speed from the initial point, the speed of the preceding vehicle when the preceding vehicle of the preceding vehicle reaches the end point of the main road control area is calculated;

[0096] Determine the speed of the preceding vehicle and calculate the distance traveled by the preceding vehicle after accelerating to the maximum speed, and determine whether the traveled distance is less than the distance between the preceding vehicle and the end point of the control area at the beginning of the gap; if so, calculate the time it takes for the preceding vehicle to reach the end point of the control area after uniformly accelerating to the maximum speed; otherwise, calculate the time it takes for the preceding vehicle to reach the end point of the control area after uniformly decelerating;

[0097] Calculate the position of the following vehicle based on the time when the leading vehicle reaches the end point of the control area;

[0098] The gap between the front and rear vehicles is calculated based on the position of the rear vehicle to determine whether the gap between the front and rear vehicles meets the minimum safety gap; if so, the adjusted gap is used as a main road to merge into the feasible gap; otherwise, the adjustment fails.

[0099] In this embodiment, when the following vehicle corresponding to the control gap decelerates at a comfortable deceleration and the leading vehicle accelerates at the maximum safe acceleration, it is determined whether the minimum safe merging distance is met before the leading vehicle reaches the end of the main road control area. Based on method 2, the time when the leading vehicle A reaches the end of the control area is calculated. Then, based on method 1, the time at which vehicle B is behind gap i is calculated. Location at the time Thus, the maximum possible vehicle distance ΔX between the front vehicle A and the rear vehicle B in the i-th gap is obtained. i ” , ' AB for:

[0100]

[0101] If ΔX” i,AB Greater than the safety distance S safe , then the gap is considered to be a feasible gap, otherwise, method 3 fails.

[0102] S2. According to the feasible gap for merging into the main road and the time when the vehicle arrives at the end of the control area, a trajectory optimization model is established with the goal of minimizing the vehicle operation energy consumption. The trajectory optimization model is used to traverse all possible main road gaps for merging into, and the feasible gap with the minimum energy consumption is selected as the merging gap for collaborative optimization control of vehicle trajectories.

[0103] In an optional embodiment of the present invention, according to the feasible gap for merging into the main road and the time when the vehicle arrives at the end of the control area, a trajectory optimization model is established with the goal of minimizing the energy consumption of vehicle operation, and all possible main road gaps for merging into are traversed using the trajectory optimization model, and the feasible gap with the minimum energy consumption is selected as the merging gap for vehicle trajectory collaborative optimization control, including:

[0104] Determine whether the vehicle merging into the ramp is an intelligent connected vehicle or a manually driven vehicle;

[0105] If the ramp-merging vehicle is an intelligent connected vehicle, the minimum arrival time of the preceding vehicle and the ramp-merging vehicle at each time slot of the main road is calculated respectively, and the minimum arrival time of the ramp-merging vehicle at the end of the acceleration zone is determined from front to back according to the feasible gaps of the main road merging. If so, a trajectory optimization model is established with the goal of minimizing the vehicle's running energy consumption, and the energy consumption corresponding to the current time slot is determined using the trajectory optimization model. The feasible gap with the minimum energy consumption is selected as the merging gap to perform vehicle trajectory collaborative optimization control.

[0106] If the ramp-merging vehicle is a manually driven vehicle, the time it takes for the ramp-merging vehicle to reach the merging point according to the car-following model is calculated, and then the time it takes for the preceding vehicle on the main road to arrive at the merging point in each time slot is calculated based on the feasible gap for merging into the main road, and the possible merging time slots for the ramp-merging vehicle are determined. Finally, the ramp-merging vehicle is made to follow the preceding vehicle in the ramp control area according to the car-following model, and at the same time, follow the preceding vehicle in the main road time slot when entering the acceleration area, until the merging conditions are met.

[0107] Reference Figure 3 In this embodiment, the collaborative optimization of ramp-merging vehicles ICV includes:

[0108] When the ramp merging vehicle is an ICV, corresponding to each feasible gap i∈I F In the proposed method, the minimum arrival time of the previous vehicle at the merging point is taken as the benchmark, and the minimum energy consumption is taken as the goal to establish a trajectory optimization model. The energy consumption of the vehicles before and after the gap and the ramp cooperative vehicles merging into the gap is calculated, and then the vehicle with the minimum energy consumption is selected to merge into the gap.

[0109] First set a virtual confluence point X in the fixed merging area R_vmer , which represents the position where the ramp-in vehicle R merges into the main line. This point is not for the vehicle to merge at a fixed point, but for the convenience of evaluating the efficiency and energy consumption of the vehicle merging sequence. The specific merging point of the ramp vehicle is not fixed, and it only needs to merge before the end of the merging area. First, calculate the time when the front vehicle A of the i-th gap reaches the end of the control area. and corresponding speed Then calculate the acceleration process from the end point of the control area to the confluence point, the minimum arrival time Thus, the minimum arrival time of vehicle A in front of each gap from the control area to the merging point is obtained. The running time of the i-th gap front vehicle A from the end of the main road control area to the merging point is calculated into three parts. The first part is the time t that the front vehicle A accelerates to the maximum speed. i,A,acc1 The second part is the time t that the vehicle runs at a constant speed for a certain distance at the maximum speed. i,A,acc2 The third part is the time t when the vehicle decelerates uniformly to the merging speed at the merging point i,A,acc3 , calculated as:

[0110]

[0111]

[0112] Where: v max is the maximum speed limit of the vehicle, v m is the vehicle merging speed, a max is the maximum acceleration, a min is the maximum deceleration. Considering that the front car of the gap i and the rear car (i.e. the front car of gap i is the rear car of gap i-1) must meet the safety distance h, The calculation method is:

[0113]

[0114] Where h is the maximum headway of ICV, that is, the time interval between the front ends of two consecutive vehicles passing through a certain section.

[0115] By calculating all feasible gaps i∈I FTime when the preceding vehicle arrives at the merging point Get the potential arrival time of ramp vehicles arriving at the merging point and merging gap

[0116] by For the time point when the ramp vehicle merges into the main line, the trajectory planning is performed for the vehicles with ICV before and after the selected gap i and the ramp-coordinated ICV vehicles. Under the premise of ensuring safe and timely merging into the main line, the gap with the minimum energy consumption is selected as the merging gap. In this regard, this section proposes a mathematical optimization model to allow the vehicles before and after the main line gap and the ramp-coordinated ICV to obtain an optimal acceleration / deceleration curve to minimize the vehicle energy consumption C. The objective function is:

[0117]

[0118] To obtain the optimal acceleration / deceleration curve, the decision variable is the vehicle from t o to i,M The vehicle acceleration a ve (t), and its constraints are as follows:

[0119]

[0120]

[0121] Among them, min is the minimum value function, C i is the vehicle energy consumption corresponding to the i-th time slot on the main road, a ve is the vehicle acceleration, ve = A, B, R is the leading vehicle A and the trailing vehicle B and their ramp cooperative vehicle R when the front and rear vehicles in the selected gap are intelligent connected vehicles ICV, t i,M is the time when the ramp cooperative vehicle R arrives at the merging point, t i,M = v min is the minimum speed of the vehicle, v ve is the vehicle ve speed, v max is the maximum speed, a min is the minimum acceleration of the vehicle, a max is the maximum acceleration of the vehicle, v m is the vehicle merging speed, x ve is the vehicle ve position, X ve_mer is the vehicle merging position, t0 is the initial time, X ve is the vehicle position, t is the calculated time when a given vehicle arrives at the merging point, and the corresponding time of the vehicle in front of the main line gap i is The corresponding time for ramp vehicles is

[0122] The first and second equations of the model's constraint conditions represent the restrictions on vehicle speed and acceleration to ensure driving safety; the third equation represents the speed of the ICV vehicle and its ramp cooperative vehicle before and after the selected gap reaches the merging point equal to the merging speed v m , so that it can ensure the safety of ramp vehicles when they complete the merging; the fourth formula indicates that the ICV vehicle and its ramp cooperative vehicle reach the merging point at the specified position before and after the selected gap. When the vehicle is a ramp merging vehicle, that is, ve=R, the vehicle arrives at the specified merging point position X R_mer , when the vehicle ve is the gap front vehicle A or the gap rear vehicle B, X A_mer =X R_mer +v m ·h I_I , X B_mer =X R_mer -v m ·h I_I ; The fifth equation represents the dynamic equation between the vehicle speed v and the acceleration a when the ramp vehicle reaches the merging point.

[0123] The sixth equation represents the dynamic equation between the vehicle position S and the velocity v when the ramp vehicle reaches the merging point. F The corresponding energy consumption C i Then select Energy Consumption C i The smallest gap i is the merging gap and is removed from the selectable gaps in the next stage, that is, I=I / i.

[0124] The collaborative optimization of ramp HDV in this embodiment includes:

[0125] When the ramp merging vehicle is an HDV, considering the uncertainty of the HDV vehicle's running trajectory, the car-following model is used to estimate the arrival time of the ramp vehicle at the merging point, and then for each main road feasible gap i∈I F , according to the gap adjustment method, the vehicle speed is guided and the most suitable merging vehicle gap is calculated, so that the ramp vehicle can reach the merging gap as expected. The collaborative optimization method for ramp merging vehicles is HDV as follows:

[0126] (1) Estimated time for ramp vehicles to arrive at the merging point

[0127] For the ramp HDV currently being regulated, first sort all ramp vehicles in the control area from front to back, assuming n r is the number of the ramp vehicle in the control area, and the status (position, speed, acceleration) of the ramp vehicle itself and all the vehicles behind it in the control area is obtained. r When it is HDV, the IDM following model is called; otherwise, when the ramp vehicle n rFor ICV, if the front vehicle n r+1 When HDV is selected, the ACC model is called. If the front vehicle n r+1 When it is ICV, the CACC model is called to obtain the status of all ramp vehicles in the next stage.

[0128] After obtaining the status information of all ramp vehicles at the current time step k, determine whether the position of the ramp HDV currently being regulated has reached the end of the control area. If not, repeat the above process to obtain the vehicle information at the next moment until the ramp vehicle reaches the end of the acceleration lane, thereby obtaining the expected time for the ramp HDV vehicle to reach the end point of the control area. and speed Then calculate the time it takes for the ramp vehicle to accelerate from the end point of the control area to the merging speed for:

[0129]

[0130] where a dec For comfortable acceleration.

[0131] Finally, we get the travel distance S after the ramp vehicle reaches the merging speed. ramp_mer for:

[0132]

[0133] Then accelerate to the position X of the merging speed R,mer =X Col_end +S ramp_mer As an entry point.

[0134] (2) Estimate the time it takes for the preceding vehicle to arrive at the merging point at each gap

[0135] The time when the front vehicle A in the ith gap in the main road reaches the end of the control area is Speed The time it takes for the vehicle A in front of the gap to change speed to the merging speed and then reach the merging point at a constant speed for:

[0136]

[0137] where t i,mer_acce It is the running time of vehicle A in front of the i-th gap from entering the merging area to the joining point.

[0138] t i,mer_acce The calculation method is as follows: First, calculate the time when the front vehicle A of the i-th gap reaches the end of the control area and corresponding speed According to the uniformly accelerated linear motion formula, we can get the acceleration a of the front vehicle A in the i-th gap at a comfortable acceleration a. dec By speed Accelerate and decelerate to the merging speed v m Distance When S ramp_mer ≥ΔS c,m When S ramp_mer <ΔS c,m When the initial arrival speed at the merge area is When the vehicle decelerates to the merging speed and then arrives at the merging point at a uniform speed, When the vehicle is uniformly accelerated to the merging speed and then arrives at the merging point at a uniform speed, we can get t i,mer_acce for:

[0139]

[0140] Use the above formula to calculate the gap time of the preceding vehicle arriving at the merging point corresponding to each gap i The preceding vehicle corresponding to gap i-1 is the following vehicle of gap i. When the preceding vehicle of gap i reaches the merging point, the gap time And the gap i behind the car When , it means that the ramp vehicle can just merge into this gap, so this gap is selected as the merging gap for the ramp vehicle and is removed from the selectable gaps in the next stage, that is, I = I / i.

[0141] (3) Main road collaborative control method

[0142] For the gap i selected in (2), if the gap spacing is larger than the merging safety gap, no adjustment is performed; if it is smaller than the safety gap, the vehicle speed is guided according to the gap adjustment method, so that the ramp vehicle can safely merge into the main road in the merging area.

[0143] The gap adjustment method is to first determine the type of vehicle in front and behind the gap. If it is an HDV, it will continue to drive according to the following model. If the front vehicle is an ICV, the front vehicle will follow the trajectory optimization model and input the given Plan the trajectory of the front vehicle A. When the ramp vehicle reaches the merging point X ramp_mer =X Col_End +S ramp_mer When the vehicle position X i,A,mer =X ramp_mer +v m ·h H_I , where X Col_End is the end position of the control zone, S ramp_mer is the driving distance into the merge zone, h H_Iis the safe headway when the front vehicle is an ICV and the rear parking space is an HDV. If the rear vehicle in the gap is an ICV, the vehicle trajectory of the rear vehicle B is planned in the same way as the calculation method of the front vehicle in the gap. When the ramp vehicle reaches the merging point X ramp_mer When the vehicle position X i,B,mer =X ramp_mer -v m ·h H_I .

[0144] In order to explain the method of the present invention, an implementation case is given below to verify and analyze the model and algorithm. SUMO and Python are used for joint development to verify the collaborative control scheme of vehicle merging trajectories in the merging area of ​​a highway under mixed traffic flow. SUMO (Simulation of Urban MObility) is an open source, highly portable, multimodal traffic simulation tool suitable for large-scale traffic networks.

[0145] In order to ensure the continuous traffic flow of the simulated road section, a vehicle generation model was established. The theoretical capacity of mixed traffic was calculated to obtain the number of generated vehicles under low, medium and high density. The theoretical capacity of mixed traffic can be calculated as:

[0146]

[0147] Where C mix represents the theoretical capacity of mixed traffic (veh / h / lane), P I represents the penetration rate of ICV. HDV 、h ACC and h CACC They represent the expected time intervals, with values ​​of 1.5s, 1.1s, and 0.6s. e Indicates the equilibrium speed (maximum speed of the main road v max ), s o lv is the vehicle static clearance and vehicle length, which are 2m and 500m respectively. The theoretical capacity of the main line is 2143, 2338, 2647 and 3158 (veh·h -1 ). The main line and ramp flow are input as follows:

[0148] Q m =C mix ·P ρ ·(1-P η )

[0149] Q r =C mix ·P ρ ·P η

[0150] Among them, P ρ is the percentage of total traffic capacity, P η is the ratio of vehicles on the ramp.

[0151] Aiming at the vehicle merging scenario at the entrance ramp of the highway under mixed traffic flow, a simulation experiment of the collaborative merging control under mixed traffic flow in the merging area of ​​the highway was carried out based on the SUMO simulation platform. Firstly, the merging effects of no control, only using the gap adjustment control strategy (Strategy 1), and the strategy of the present invention (Strategy 2) under different traffic flows and ICV penetration rates were compared. Secondly, the merging effects of each strategy under different ICV penetration rates under high density were analyzed. Then, the influence of different control area lengths in the collaborative optimization strategy of vehicle trajectory planning on the merging effect was further analyzed.

[0152] In the merging scenario, the main line is 1400m long, of which the length before the merging area is 700m and the main line control area is 500m long; the ramp is 400m long, of which the ramp control area is 200m; the merging area is 200m long, the lane width is 3.75m, the simulation time is 600s (the vehicle input time is 300s), the simulation step is 0.1s, the decision control step is 0.5s, the vehicle lateral position is the center of the lane, and the maximum initial speed of the main line vehicle is 25.0m·s -1 , the maximum initial speed of ramp vehicles is 16.7 m·s -1 The simulation parameters are shown in Table 1.

[0153] Table 1 Simulation parameters

[0154]

[0155]

[0156] In the case study, two schemes, no control strategy and vehicle dynamic cooperative merging control strategy (Strategy 2), were mainly tested for different ICV penetration rates and road densities. The specific test results are shown below:

[0157] Table 2 Comparison of strategy performance of different strategies with different ICV penetration rates at different densities

[0158]

[0159] from Figures 5 to 12 As can be seen from Table 2, compared with the strategy without strategy, under the coordinated merging control, it can be seen from the vehicle trajectory and speed distribution diagram that the vehicle trajectory with the control strategy is more average, which means that there are fewer cases of vehicle congestion during the merging process, the vehicle merges through the merging area faster, and the vehicle passing efficiency is higher; and the vehicle trajectory color changes less, which means that the vehicle speed trajectory is smoother, the vehicle acceleration change is smaller, and the energy consumption is lower.

[0160] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0161] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0162] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0163] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

[0164] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A method for collaboratively controlling vehicle merging trajectories in a merging area of ​​a highway under mixed traffic flow, characterized in that: The following steps are involved: The expressway merging area is divided into a control area and a merging area. The feasible gap for merging into the main road is determined based on the vehicle types and vehicle status before and after the gap in the control area, as well as the coordinated adjustment range of the safe distance and the feasible gap between different vehicle gaps. According to the feasible gap for merging into the main road and the time when the vehicle arrives at the end of the control area, a trajectory optimization model is established with the goal of minimizing the vehicle operation energy consumption. The trajectory optimization model is used to traverse all possible main road gaps for merging, and the feasible gap with the minimum energy consumption is selected as the merging gap for collaborative optimization control of vehicle trajectories.

2. The method for cooperatively controlling vehicle merging trajectories in a merging area of ​​a highway under mixed traffic flow according to claim 1, characterized in that: The feasible gap for merging into the main road is determined based on the vehicle type and status before and after the gap in the control area, as well as the coordinated adjustment range of the safe distance and the feasible gap between different vehicle gaps, including: Starting from the first vehicle on the main line of the main road control area, calculate the distance between the vehicles before and after the main road control area gap; Determine whether the distance between the vehicles before and after the gap is greater than or equal to the minimum safe gap; if so, treat the gap as a main road and merge into a feasible gap; otherwise, adjust before the end point of the main road control area according to the type of vehicles before and after the gap to meet the requirement of a feasible gap.

3. The method for cooperatively controlling vehicle merging trajectories in a merging area of ​​a highway under mixed traffic flow according to claim 2, characterized in that: According to the vehicle types before and after the gap, adjustments are made before the end point of the main road control area to meet a feasible gap, including: When both the front and rear vehicles are intelligent connected vehicles, the rear vehicle is decelerated at a comfortable deceleration and the front vehicle is driven at a constant speed to determine whether the minimum safety gap is met when the front vehicle reaches the end point of the main road control area; if so, the adjusted gap is used as a main road to merge into a feasible gap; otherwise, the front vehicle is accelerated at the maximum safety acceleration and the rear vehicle is driven at a constant speed to determine whether the minimum safety gap is met when the front vehicle reaches the end point of the main road control area; if so, the adjusted gap is used as a main road to merge into a feasible gap; otherwise, the rear vehicle is decelerated at a comfortable deceleration and the front vehicle is accelerated at the maximum safety acceleration to determine whether the minimum safety gap is met when the front vehicle reaches the end of the main road control area; if so, the adjusted gap is used as a main road to merge into a feasible gap; otherwise, the gap is an infeasible gap; When the front and rear vehicles are intelligent network-connected vehicles and manually driven vehicles, the rear vehicle is decelerated at a comfortable deceleration and the front vehicle is driven at a constant speed to determine whether the minimum safety gap is met when the front vehicle reaches the end point of the main road control area; if so, the adjusted gap is regarded as a feasible gap that merges into the main road; otherwise, the gap is an infeasible gap; When the front and rear vehicles are manually driven vehicles and intelligent networked vehicles, the front vehicle is accelerated at the maximum safe acceleration and the rear vehicle is driven at a constant speed to determine whether the minimum safe gap is met when the front vehicle reaches the end point of the main road control area; if so, the adjusted gap is regarded as a feasible gap that merges into the main road; otherwise, the gap is an infeasible gap; When both the front and rear vehicles are manually driven vehicles, the rear vehicle is decelerated at a comfortable deceleration and the front vehicle is driven at a constant speed to determine whether the minimum safety gap is met when the front vehicle reaches the end point of the main road control area; if so, the adjusted gap is regarded as a feasible gap merging into the main road; otherwise, the gap is an infeasible gap.

4. The method for cooperatively controlling vehicle merging trajectories in a merging area of ​​a highway under mixed traffic flow according to claim 3, characterized in that: The rear vehicle is decelerated at a comfortable deceleration rate and the front vehicle is driven at a constant speed to determine whether the minimum safety gap is met when the front vehicle reaches the end point of the main road control area, including: According to the speed of the rear vehicle and the time it takes for the front vehicle to reach the end point of the main road control area at a constant speed, the speed of the rear vehicle until it decelerates until the end point of the main road control area is calculated; Determine whether the speed of the following vehicle that has been decelerating until the end point of the main road control area is less than the minimum speed limit; if so, calculate the position of the following vehicle that has been decelerating until the end point of the main road control area; otherwise, calculate the position of the following vehicle that has been decelerating first and then driving at a constant speed in the operating period of the control area; The distance between the front and rear vehicles is calculated based on the position of the rear vehicle when the front vehicle reaches the end point of the control area, and it is determined whether the distance between the front and rear vehicles meets the minimum safety gap. If so, the adjusted gap is used as a main road to merge into a feasible gap; otherwise, the adjustment fails.

5. The method for cooperatively controlling vehicle merging trajectories in a merging area of ​​a highway under mixed traffic flow according to claim 3, characterized in that: Accelerate the front vehicle at the maximum safe acceleration and drive the rear vehicle at a constant speed to determine whether the minimum safety gap is met when the front vehicle reaches the end point of the main road control area, including: According to the time taken by the preceding vehicle of the preceding vehicle to reach the end point of the main road control area at a uniform speed from the initial point, the speed of the preceding vehicle when the preceding vehicle of the preceding vehicle reaches the end point of the main road control area is calculated; Determine the speed of the preceding vehicle and calculate the distance traveled by the preceding vehicle after accelerating to the maximum speed, and determine whether the traveled distance is less than the distance between the preceding vehicle and the end point of the control area at the beginning of the gap; if so, calculate the time it takes for the preceding vehicle to reach the end point of the control area after uniformly accelerating to the maximum speed; otherwise, calculate the time it takes for the preceding vehicle to reach the end point of the control area after uniformly decelerating; The distance between the front and rear vehicles is calculated based on the time when the front vehicle reaches the end point of the control area to determine whether the distance between the front and rear vehicles meets the minimum safety gap; if so, the adjusted gap is used as a main road to merge into the feasible gap; otherwise, the adjustment fails.

6. The method for cooperatively controlling vehicle merging trajectories in a merging area of ​​a highway under mixed traffic flow according to claim 3, characterized in that: The rear vehicle is decelerated at a comfortable deceleration and the front vehicle is accelerated at a maximum safe acceleration, and it is determined whether the minimum safety gap is met when the front vehicle reaches the end of the main road control area, including: According to the time taken by the preceding vehicle of the preceding vehicle to reach the end point of the main road control area at a uniform speed from the initial point, the speed of the preceding vehicle when the preceding vehicle of the preceding vehicle reaches the end point of the main road control area is calculated; Determine the speed of the preceding vehicle and calculate the distance traveled by the preceding vehicle after accelerating to the maximum speed, and determine whether the traveled distance is less than the distance between the preceding vehicle and the end point of the control area at the beginning of the gap; if so, calculate the time it takes for the preceding vehicle to reach the end point of the control area after uniformly accelerating to the maximum speed; otherwise, calculate the time it takes for the preceding vehicle to reach the end point of the control area after uniformly decelerating; Calculate the position of the following vehicle based on the time when the leading vehicle reaches the end point of the control area; The gap between the front and rear vehicles is calculated based on the position of the rear vehicle to determine whether the gap between the front and rear vehicles meets the minimum safety gap; if so, the adjusted gap is used as a main road to merge into the feasible gap; otherwise, the adjustment fails.

7. The method for cooperatively controlling vehicle merging trajectories in a merging area of ​​a highway under mixed traffic flow according to claim 1, characterized in that: According to the feasible gaps for merging into the main road and the time when the vehicle arrives at the end of the control area, a trajectory optimization model is established with the goal of minimizing the vehicle's running energy consumption. The trajectory optimization model is used to traverse all possible main road gaps for merging into the main road, and the feasible gap with the minimum energy consumption is selected as the merging gap for vehicle trajectory collaborative optimization control, including: Determine whether the vehicle merging into the ramp is an intelligent connected vehicle or a manually driven vehicle; If the ramp-merging vehicle is an intelligent connected vehicle, the minimum arrival time of the preceding vehicle and the ramp-merging vehicle at each time slot of the main road is calculated respectively, and the minimum arrival time of the ramp-merging vehicle at the end of the acceleration zone is determined from front to back according to the feasible gaps of the main road merging. If so, a trajectory optimization model is established with the goal of minimizing the vehicle's running energy consumption, and the energy consumption corresponding to the current time slot is determined using the trajectory optimization model. The feasible gap with the minimum energy consumption is selected as the merging gap to perform vehicle trajectory collaborative optimization control. If the ramp-merging vehicle is a manually driven vehicle, the time it takes for the ramp-merging vehicle to reach the merging point according to the car-following model is calculated, and then the time it takes for the preceding vehicle on the main road to arrive at the merging point in each time slot is calculated based on the feasible gap for merging into the main road, and the possible merging time slots for the ramp-merging vehicle are determined. Finally, the ramp-merging vehicle is made to follow the preceding vehicle in the ramp control area according to the car-following model, and at the same time, follow the preceding vehicle in the main road time slot when entering the acceleration area, until the merging conditions are met.

8. The method for cooperatively controlling vehicle merging trajectories in a merging area of ​​a highway under mixed traffic flow according to claim 7, characterized in that: The minimum arrival time of the leading vehicle in the main road time slot to the end of the acceleration zone is calculated as follows: The running time of the leading vehicle in the main road gap from the end point of the main road control area to the merging point is divided into the time for the leading vehicle to accelerate to the maximum speed, the time for the leading vehicle to run a certain distance at the maximum speed, and the time for the leading vehicle to decelerate uniformly to the merging speed of the merging point; The following formula is used to calculate the minimum arrival time of the leading vehicle in the main road time slot to the end of the acceleration zone, expressed as: in, is the minimum arrival time of the front vehicle A at the end of the acceleration zone in the i-th time slot on the main road, max is the maximum value function, t i,A,acc1 is the time it takes for the front vehicle to accelerate to the maximum speed, t i,A,acc2 is the time it takes for the front vehicle to run a certain distance at a constant speed at maximum speed, t i,A,acc3 is the time it takes for the front vehicle to decelerate uniformly to the merging speed at the merging point, It is the minimum arrival time of the leading vehicle in the i-1th time slot on the main road from the end point of the control area to the merging point, and h is the maximum headway time.

9. The method for cooperatively controlling vehicle merging trajectories in a merging area of ​​a highway under mixed traffic flow according to claim 7, characterized in that: The minimum arrival time for a ramp-merging vehicle to reach the end of the acceleration zone is calculated as follows: in, is the minimum arrival time for vehicles merging into the ramp to reach the end of the acceleration zone, is the minimum arrival time of the preceding vehicle A at the end of the acceleration zone in the i-th time slot on the main road, and h is the maximum headway time.

10. The method for cooperatively controlling vehicle merging trajectories in a merging area of ​​a highway under mixed traffic flow according to claim 1 or 7, characterized in that: The trajectory optimization model is established with the goal of minimizing vehicle running energy consumption: min st Among them, min is the minimum value function, C i is the vehicle energy consumption corresponding to the i-th time slot on the main road, a ve is the vehicle acceleration, ve = A, B, R is the leading vehicle A and the trailing vehicle B and their ramp cooperative vehicle R when the front and rear vehicles in the selected gap are intelligent connected vehicles ICV, t i,M is the time when the ramp cooperative vehicle R arrives at the merging point, v mi n is the minimum speed of the vehicle, v ve is the vehicle ve speed, v max is the maximum speed, a min is the minimum acceleration of the vehicle, a max is the maximum acceleration of the vehicle, v m is the vehicle merging speed, x ve is the vehicle ve position, X ve_mer is the vehicle merging position, t0 is the initial time, X ve is the vehicle position, and t is the time when the vehicle arrives at the merging point.

Images