CN110176138A - A kind of active traffic induction method of crossing grade - Google Patents

Abstract

The invention discloses an intersection-level active traffic guidance method, which includes the analysis of the intersection-level active traffic guidance strategy, judging the traffic state of the vehicle arrival cycle, judging the standard for judging that the vehicle speed is a reasonable speed, and the traffic state and signal state according to the vehicle arrival cycle , implement the corresponding intersection-level active traffic guidance algorithm; through the analysis of the intersection-level active traffic guidance strategy, the guidance range is determined to be the guidance area and the queuing range; then four criteria are set to judge whether the speed is reasonable; then when the vehicle enters When guiding the area, judge the traffic state of the vehicle arrival cycle, that is, unsaturated, quasi-saturated, and oversaturated states; finally, according to different traffic states and signal states of the vehicle arrival cycle, implement the corresponding intersection-level active traffic guidance algorithm, so as to realize Reduce the number of stops and waiting times when vehicles enter intersections.

Description

An intersection-level active traffic guidance method

technical field

The invention relates to the field of guidance methods, in particular to an intersection-level active traffic guidance method.

Background technique

In the traditional traffic environment, the driver's decision on speed adjustment comes from the subjective judgment of the distance between the front of the vehicle, the speed of the vehicle in front and the traffic conditions of the adjacent road. Especially when the moving vehicle reaches the intersection range, it is difficult for the driver to determine the current remaining effective green light time or effective red light time, as well as the length of the waiting team. Therefore, the driver cannot pass the intersection with the expected effect by adjusting the speed reasonably. The lack of information available to drivers is an important factor in the formation of intersection delays.

If active traffic guidance can be carried out at the intersection, that is, to induce the driving speed of the vehicle and guide the vehicle to adjust the driving speed reasonably, then the vehicle can be stopped or the parking time can be shortened when passing the intersection, thereby reducing intersection delays and reducing traffic. Congestion and environmental pollution, improve driving efficiency.

Contents of the invention

In view of this, in order to solve the above-mentioned problems in the prior art, the present invention provides an intersection-level active traffic guidance method, which aims to solve the problem of not stopping or shortening the parking time when vehicles pass through the intersection, thereby reducing intersection delays , reduce traffic congestion and environmental pollution, and improve driving efficiency.

In order to achieve the above object, the technical solution of the present invention is as follows.

An intersection-level active traffic guidance method, comprising the following steps:

Step 1. Active traffic guidance strategy analysis at intersection level;

Step 2, judging the traffic state of the vehicle arrival period;

Step 3, judging that the speed of the vehicle is a reasonable speed standard;

Step 4. According to the traffic state and signal state of the vehicle arrival cycle, implement the corresponding intersection-level active traffic guidance algorithm.

Further, the step 1 includes the following steps:

Step 11, precondition analysis, R _d represents the length of the induction area, R _q represents the length of the queuing range, when the vehicle enters the induction area and the queuing range, it communicates with the drive test equipment in real time, and provides the driving information of the vehicle to the drive test equipment, The inducing area is the range in which the vehicle speed is induced and adjusted, that is, the range from the stop line to the _upstream length R _d ; The length from the line to the upstream is R _q , and R _q < R _d ;

Step 12, ideal state analysis, when the vehicle arrives at the intersection, the vehicle release state at the intersection is the green light state, that is, when the saturation of the intersection is unsaturated or quasi-saturated, the vehicle can pass through the intersection without stopping. The situation occurs after the queuing length reaches the maximum value and before the red light duration of the intersection indicator light of the next cycle begins.

Further, the step 2 includes the following steps:

Step 21. Calculate the intersection saturation through the formula, the intersection saturation is the maximum value of each phase saturation of the intersection, the formula is:

Among them, x is the intersection saturation, q is the flow rate of phase-critical traffic flow, and Q is the traffic capacity;

Step 22. Judging the intersection saturation state, the intersection saturation is divided into unsaturated state, quasi-saturated state and supersaturated state. When x is less than 1, it is unsaturated state; when x is equal to 1, it is quasi-saturated state state; when x is greater than 1, it is an oversaturated state;

Step 23. When the intersection saturation is oversaturated, the accumulated vehicles and real-time vehicles within the accumulated time cannot be cleared within the release time. After the release time is over, the remaining vehicles will be accumulated as the accumulated vehicles for the next cycle, occupying the next cycle’s accumulated vehicles. Release time, the release time is the duration of the green light of the intersection indicator light, and the cumulative time refers to the duration of the red light of the intersection indicator light.

Further, the step 3 includes the following steps:

Step 31. Judging the vehicle speed Whether the speed limit V _lim specified by the road section is exceeded, when there is no speed limit specified by the road section, let V _lim = 80km/h;

Step 32. Determine whether the acceleration is within the reasonable range [-a _MAX , a _MAX ]. The reasonable range of acceleration is different for different models: a _MAX = 5m/s ² for small cars; a _MAX = 4m/s ² for medium-sized cars ; Large vehicle a _MAX = 3m/s ² ;

Step 33. Judging the vehicle speed Whether it can be accepted by the driver, the speed change cannot exceed 60% of the original speed;

Step 34. Determine whether the driving conditions allow speed adjustment. The distance between vehicles in front of the vehicle needs to be able to allow the vehicle to accelerate. If the distance between vehicles cannot meet the speed requirements, it is necessary to check whether the speed can be updated by changing lanes. If neither allowed, speed It is regarded as an unreasonable induced speed.

Further, the step 4 includes the following steps:

Step 41. If the traffic state of the arrival cycle is unsaturated and the signal state of the arrival time is the effective green light time, the state of the arrival cycle is an ideal state and a non-ideal state, and corresponding induction algorithms need to be established respectively; otherwise, execute the step 42;

Step 42. If the traffic state of the arrival period is unsaturated and the signal state at the arrival time is the effective red light time, vehicle i travels to the boundary of the queue range at the initial speed v ₀ , and the signal state is still the effective red light time, which needs to be established Corresponding intersection-level active traffic guidance method; otherwise, execute step 43;

Step 43. If the traffic state of the arrival cycle is oversaturated, all vehicles arriving at the intersection must stop before they can pass through the intersection. For the remaining vehicles in the queue, the waiting time also includes the effective red light of the next cycle time, which is the state of oversaturation and delay, and corresponding intersection-level active traffic guidance methods need to be established.

Further, the effective green light time refers to the transit time that can be used by the signal phase within one signal cycle and is converted to the corresponding green light release time when it is ideally utilized; the effective red light time refers to the transit time of the signal phase within one signal cycle. The red light time of the signal phase is converted into the red light release time corresponding to the ideal stop.

Further, the step 41 includes:

The ideal state is that when the vehicle i travels to the end of the queuing range at the initial speed _v0 , the queuing length has reached the maximum value, and the vehicle can pass the stop line within the remaining effective green light time, then the corresponding induction strategy is: initial induction velocity is v ₀ , from the induction range boundary R _d to the position of the maximum queue length of the arrival period The induced velocity in this interval is the original velocity v ₀ ; from to the stop line, still traveling at speed v ₀ , or at is the acceleration, and gradually accelerates to Then drive at a constant speed; each induction speed corresponds to an induction strategy;

Ideally, the algorithm steps are as follows:

in, Indicates the time when vehicle i travels to the boundary of the queuing range at speed v ₀ ; Indicates that the nth signal cycle is in a normal state; Indicates that when the vehicle i travels to the position of the maximum queue length, the queue length has reached the maximum value and begins to dissipate; Indicates that the time for vehicle i to reach the stop line is less than the start time of the effective red light in the next cycle, where _tl represents the time for the vehicle to travel from the position of the maximum queuing length to the stop line, if but like Then t _l is determined by the acceleration and speed after acceleration decision, said Indicates the target vehicle speed that needs to be accelerated or decelerated to after vehicle i reaches the maximum queuing area position in the nth cycle, is the corresponding acceleration, calculated by the following formula:

Among them, v' _t is a temporary velocity variable, a' is a temporary acceleration variable, t' is a temporary acceleration time variable; if there is no and but and The value is NULL;

In the formula (2), ② is the induced speed that meets the conditions; ③ is the limitation condition of the acceleration distance; ④ ⑤ ⑥ is the reasonable judgment standard of the induced vehicle speed; ⑦ represents Take the minimum value of all solutions in a'; in this stage, the acceleration a' is greater than or equal to 0;

like and is not NULL, then

Otherwise, it does not meet the conditions of the ideal state and should be treated as a non-ideal state;

Road(v ₀ )>0 indicates that the speed v ₀ can meet the requirements of traffic conditions, Road(v ₀ )≤0 indicates that the current traffic state does not meet the condition of vehicle speed v ₀ ; Road(v ₀ ) is defined as:

d ⁺⁽ⁱ⁾ (t) indicates the distance between vehicle i and the adjacent vehicle in front at time t; d ⁺⁽ⁱ⁾ (T ₀ )≥v ₀ indicates the conditions that vehicle i needs to meet when driving in this lane at speed v ₀ ; Indicates that vehicle i satisfies the lane change condition; Indicates the distance between vehicle i and the front and rear adjacent vehicles on the adjacent lane at time t, x can be + or -, + means the front, - means the rear; is the motivational condition for lane-changing, safety conditions for changing lanes;

When vehicle i is not allowed to change lanes at will because it is close to the intersection, let the adjacent lanes that do not meet the lane change conditions

Further, the step 41 includes:

The non-ideal state is when the vehicle i travels to the end of the queue range with speed _v0 , and the queue length does not reach the maximum value, then the corresponding induction strategy is to make its arrival time meet the ideal state of the arrival cycle, and the corresponding induction strategy is : at the initial induced velocity for From the induction range boundary to the maximum position of the queue length of the arrival period, with is the acceleration, which gradually accelerates or decelerates to driving at a constant speed; from the position with the maximum queue length to the stop line, to is the acceleration, gradually accelerating to Then drive at a constant speed; according to the time when the queue length reaches the maximum value with the length of the maximum Calculate the induced speed at which the queuing length has reached the maximum value when vehicle i travels to the end of the queue; if the induced speed exists, it is recommended that the vehicle adjust to the induced speed so as to pass through the intersection without stopping;

In the non-ideal state, the algorithm steps are as follows:

in, Indicates that when vehicle i travels to the position of the maximum queue length at speed v ₀ , the queue length has not yet reached the maximum value; Indicates the target vehicle speed that needs to be accelerated or decelerated to after vehicle i enters the induced area, is the corresponding acceleration; Indicates that when vehicle i reaches the maximum queue length position After that, it needs to accelerate to the target speed, is the corresponding acceleration;

said and The value of is calculated by the following formula:

Among them, v _t ' is a temporary velocity variable, a' is a temporary acceleration variable, t' is a temporary acceleration time variable; if there is no and but and The value is NULL;

In formula (5), ② is the condition of the ideal state, that is, the vehicle i reaches the maximum queuing length position after the queuing length reaches the maximum value in the nth arrival cycle; ③④⑤⑥ is the reasonable induced speed limit condition; ⑦ means Take the solution with the smallest absolute value among all the solutions of a';

like and is not NULL, The value of is calculated by the following formula:

Where v' _t is a temporary velocity variable, a' is a temporary acceleration variable, t' is a temporary acceleration time variable; if there is no and but and The value is NULL;

In formula (6), except ②, other parts are basically consistent with formula (2); in ②, for the vehicle to time, for the vehicle from the time it takes to travel to the stop line; Take the minimum value of a' that meets the condition, for the corresponding speed.

The meaning of is the same as that of the ideal function Road(), namely Indicates speed be able to meet the requirements of traffic conditions; defined as:

Further, the step 42 includes:

If vehicle i travels to the boundary of the queuing range at the original speed v ₀ and the signal state is the effective red light time, then the induction scheme includes:

Option 1, if the traffic state of the arrival cycle is not oversaturated, make the arrival time conform to the ideal state of the arrival cycle;

Option two, if the traffic state of the arrival cycle is not oversaturated in the previous cycle, make its arrival time conform to the ideal state of the previous cycle;

In the algorithm, it is necessary to calculate the optimal speed at which the queue length has reached the maximum value and the optimal speed at which the vehicle i travels from the maximum position of the queue length to the stop line when the vehicle i travels to the end of the queue range; if both optimal speeds exist, then It is recommended that vehicles adjust to the optimum speed to pass through the intersection without stopping; the specific algorithm is as follows:

If the traffic state of the nth arrival cycle is not supersaturated, and and are not empty, execute scheme 1; if the n-1th period is not supersaturated, and and If they are not empty, then implement the second option; if both options are feasible, then choose and The scheme corresponding to the acceleration with the smallest absolute value;

and The calculation method of is the same as formulas (5) and (6);

and The calculation method of is similar to the formulas (5) and (6), the differences are as follows:

In formula (5), formula ② becomes:

Formula ③ becomes:

In formula (6), formula ② becomes:

Formula ③ becomes:

Further, the step 43 includes:

When the traffic state of vehicle i's arrival cycle is supersaturated, it is necessary to detect whether the previous cycle and the next cycle are supersaturated cycles; The cycle is adjusted to the ideal state of the corresponding cycle; if the two adjacent cycles are in the normal state, the induction algorithm selects the scheme with the smallest change in the induced speed relative to the original speed;

If the traffic state of three consecutive arrival cycles is in an oversaturated state, or there is no ideal state induced speed in adjacent cycles, the purpose of the induction is to prevent vehicle i from entering the remaining queue of this cycle and prevent vehicles from experiencing oversaturation delays state, the corresponding induction strategy is: at the initial induction speed for The corresponding induction strategy is: from the boundary of the induction range to the distance from the stop line The induction strategy of the position is based on is the acceleration, which gradually accelerates or decelerates to Then drive at a constant speed until it reaches the end of the queue;

The induction algorithm is as follows:

in Indicates the target vehicle speed that needs to be accelerated or decelerated to in order not to enter the remaining queue after vehicle i enters the induction area, is the corresponding acceleration; define the wave speed of the queuing wave of the nth arrival cycle as

The induction speed Calculated by the following formula:

Among them, v' _t is a temporary velocity variable, a' is a temporary acceleration variable, t' is a temporary acceleration time variable; if there is no but and The value is NULL;

In formula (10), Indicates that the vehicle has traveled to the stop line The time of the position, at the nth arrival cycle, and less than or equal to from stop line to The position of is the part of the non-remaining queue in the queue length; is the queuing wave propagating from the stop line to The time of the position; if the vehicle reaches the queue length Arriving at the queuing queue earlier, then the oversaturation delay state can be avoided.

Compared with the prior art, the beneficial effect of an intersection-level active traffic guidance method of the present invention is: to conduct active traffic guidance at the intersection, that is, to induce the driving speed of the vehicle, and to guide the vehicle to adjust the driving speed reasonably, so that the vehicle is at the intersection. When passing through an intersection, it can effectively reduce the number of parking at the intersection and the average waiting time of vehicles at the intersection, thereby reducing intersection delays, reducing traffic congestion and environmental pollution, and improving driving efficiency.

Description of drawings

FIG. 1 is a flow chart of an intersection-level active traffic guidance method of the present invention.

Fig. 2 is a flow chart of a guidance algorithm of an intersection-level active traffic guidance method of the present invention.

FIG. 3 is a schematic diagram of an intersection structure diagram of an intersection-level active traffic guidance method according to the present invention.

Figure 4 is a diagram of the traffic state (unsaturated) of vehicles entering the intersection.

Figure 5 is a diagram of the traffic state (quasi-saturated) of vehicles entering the intersection.

Figure 6 is a diagram of the traffic state (oversaturation) of vehicles entering an intersection.

Fig. 7 is an intersection simulation effect diagram of an intersection-level active traffic guidance method of the present invention.

Fig. 8 is a road parking number diagram of an intersection-level active traffic guidance method of the present invention.

Fig. 9 is a diagram of the average waiting time of vehicles in an intersection-level active traffic guidance method of the present invention.

Detailed ways

The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be pointed out that if there are any processes or symbols that are not specifically described in detail below (such as commonly used symbols in individual programming algorithms), those skilled in the art can understand or implement them with reference to the prior art. The described embodiments are only some of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work are all Belong to the protection scope of the present invention.

As shown in Figure 1, it is a flow chart of an active traffic guidance method at a crossing level of the present invention, comprising the following steps:

Step 1. Active traffic guidance strategy analysis at intersection level;

Step 2, judging the traffic state of the vehicle arrival period;

Step 3, judging that the speed of the vehicle is a reasonable speed standard;

Step 4. According to the traffic state and signal state of the vehicle arrival cycle, implement the corresponding intersection-level active traffic guidance algorithm.

Preferably, the step 1 includes the following steps:

Step 11, precondition analysis, when the vehicle enters the induction area and the queuing range, it communicates with the road test equipment in real time, and provides the driving information of the vehicle to the road test equipment, as shown in Figure 3, which is a kind of intersection-level active traffic control system of the present invention. Schematic diagram of the intersection structure diagram of the traffic guidance method, the guidance area _Rd is the range of induction adjustment of the vehicle speed, that is, from the stop line to the upstream point _Rd , the length of the queue range _Rq is the vehicle speed in this period The average value of the maximum queue length, that is, from the stop line to the R _q point upstream, and R _q < R _d ;

Step 12, ideal state analysis, when the vehicle arrives at the intersection, the vehicle release state at the intersection is the green light state, that is, when the saturation of the intersection is unsaturated or quasi-saturated, the vehicle can pass through the intersection without stopping. The situation occurs after the queuing length reaches the maximum value and before the red light duration of the intersection indicator light of the next cycle begins.

As shown in Figure 2, the induction algorithm flowchart of the active traffic guidance method of a kind of intersection level of the present invention, comprises the following steps in the described step 2:

Step 21. Calculate the intersection saturation through the formula, the intersection saturation is the maximum value of each phase saturation of the intersection, the formula is:

Among them, x is the intersection saturation, q is the flow rate of phase-critical traffic flow, and Q is the traffic capacity;

Step 22, judge intersection saturation state, as shown in Fig. 4, Fig. 5, Fig. 6, for entering intersection vehicle traffic status figure, described intersection saturation is divided into unsaturated state (Fig. 4), quasi-saturated state state (Fig. 5) and supersaturated state (Fig. 6), when x is less than 1, it is an unsaturated state; when x is equal to 1, it is a quasi-saturated state; when x is greater than 1, it is an oversaturated state;

Step 23. When the intersection saturation is oversaturated, the accumulated vehicles and real-time vehicles within the accumulated time cannot be cleared within the release time. After the release time is over, the remaining vehicles will be accumulated as the accumulated vehicles for the next cycle, occupying the next cycle’s accumulated vehicles. Release time, the release time is the duration of the green light of the intersection indicator light, and the cumulative time refers to the duration of the red light of the intersection indicator light.

Preferably, with reference to Figure 2, the step 3 includes the following steps:

Step 31. Judging the vehicle speed Whether the speed limit V _lim specified by the road section is exceeded, when there is no speed limit specified by the road section, let V _lim = 80km/h;

Step 32. Determine whether the acceleration is within the reasonable range [-a _MAX , a _MAX ]. The reasonable range of acceleration is different for different models: a _MAX = 5m/s ² for small cars; a _MAX = 4m/s ² for medium-sized cars ; Large vehicle a _MAX = 3m/s ² ;

Step 33. Judging the vehicle speed Whether it can be accepted by the driver, the speed change cannot exceed 60% of the original speed;

Step 34. Determine whether the driving conditions allow speed adjustment. The distance between vehicles in front of the vehicle needs to be able to allow the vehicle to accelerate. If the distance between vehicles cannot meet the speed requirements, it is necessary to check whether the speed can be updated by changing lanes. If neither allowed, speed It is regarded as an unreasonable induced speed.

Preferably, with reference to Figure 2, the step 4 includes the following steps:

Step 41. If the traffic state of the arrival cycle is unsaturated and the signal state of the arrival time is the effective green light time, the state of the arrival cycle is an ideal state and a non-ideal state, and corresponding induction algorithms need to be established respectively; otherwise, execute the step 42;

Step 42. If the traffic state of the arrival period is unsaturated and the signal state at the arrival time is the effective red light time, vehicle i travels to the boundary of the queue range at the initial speed v ₀ , and the signal state is still the effective red light time, which needs to be established Corresponding intersection-level active traffic guidance method; otherwise, execute step 43;

Step 43. If the traffic state of the arrival cycle is oversaturated, all vehicles arriving at the intersection must stop before they can pass through the intersection. For the remaining vehicles in the queue, the waiting time also includes the effective red light of the next cycle time, which is the state of oversaturation and delay, and corresponding intersection-level active traffic guidance methods need to be established.

Preferably, the effective green light time refers to the transit time that can be used by the signal phase in one signal cycle and is converted to the corresponding green light release time when it is ideally utilized; The red light time of the signal phase is converted into the red light release time corresponding to the ideal stop.

Preferably, said step 41 includes:

The ideal state is that when the vehicle i travels to the end of the queuing range at the initial speed _v0 , the queuing length has reached the maximum value, and the vehicle can pass the stop line within the remaining effective green light time, then the corresponding induction strategy is: initial induction velocity is v ₀ , from the induction range boundary R _d to the position of the maximum queue length of the arrival period The induced velocity in this interval is the original velocity v ₀ ; from to the stop line, still traveling at speed v ₀ , or at is the acceleration, and gradually accelerates to Then drive at a constant speed; each induction speed corresponds to an induction strategy;

Ideally, the algorithm steps are as follows:

in, Indicates the time when vehicle i travels to the boundary of the queuing range at speed v ₀ ; Indicates that the nth signal cycle is in a normal state; Indicates that when the vehicle i travels to the position of the maximum queue length, the queue length has reached the maximum value and begins to dissipate; Indicates that the time for vehicle i to reach the stop line is less than the start time of the effective red light in the next cycle, where _tl represents the time for the vehicle to travel from the position of the maximum queuing length to the stop line, if but like Then t _l is determined by the acceleration and speed after acceleration decision, said Indicates the target vehicle speed that needs to be accelerated or decelerated to after vehicle i reaches the maximum queuing area position in the nth cycle, is the corresponding acceleration, calculated by the following formula:

Among them, v' _t is a temporary velocity variable, a' is a temporary acceleration variable, t' is a temporary acceleration time variable; if there is no and but and The value is NULL;

In the formula (2), ② is the induced speed that meets the conditions; ③ is the limitation condition of the acceleration distance; ④ ⑤ ⑥ is the reasonable judgment standard of the induced vehicle speed; ⑦ represents Take the minimum value of all solutions in a'; in this stage, the acceleration a' is greater than or equal to 0;

like and is not NULL, then

Otherwise, it does not meet the conditions of the ideal state and should be treated as a non-ideal state;

Road(v ₀ )>0 indicates that the speed v ₀ can meet the requirements of traffic conditions, and Road(v ₀ )≤0 indicates that the current traffic state does not meet the condition that the vehicle speed is v ₀ ; the Road(v ₀ ) is defined as:

d ^{+ (i)} (t) represents the distance between vehicle i and the adjacent vehicle in front at time t. d ⁺⁽ⁱ⁾ (T ₀ )≥v ₀ indicates the conditions that vehicle i needs to meet when driving in this lane at speed v ₀ . Indicates that vehicle i satisfies the lane change condition; Indicates the distance between vehicle i and the front and rear adjacent vehicles on the adjacent lane at time t, x can be + or -, + means the front, - means the rear. is the motivational condition for lane-changing, safety conditions for changing lanes;

When vehicle i is not allowed to change lanes at will because it is close to the intersection, let the adjacent lanes that do not meet the lane change conditions

Preferably, said step 41 includes:

The non-ideal state is when the vehicle i travels to the end of the queue range with speed _v0 , and the queue length does not reach the maximum value, then the corresponding induction strategy is to make its arrival time meet the ideal state of the arrival cycle, and the corresponding induction strategy is : at the initial induced velocity for From the induction range boundary to the maximum position of the queue length of the arrival period, with is the acceleration, which gradually accelerates or decelerates to driving at a constant speed; from the position with the maximum queue length to the stop line, to is the acceleration, gradually accelerating to Then drive at a constant speed; according to the time when the queue length reaches the maximum value with the length of the maximum Calculate the induced speed at which the queuing length has reached the maximum value when vehicle i travels to the end of the queue; if the induced speed exists, it is recommended that the vehicle adjust to the induced speed so as to pass through the intersection without stopping;

In the non-ideal state, the algorithm steps are as follows:

in, Indicates that when vehicle i travels to the position of the maximum queue length at speed v ₀ , the queue length has not yet reached the maximum value; Indicates the target vehicle speed that needs to be accelerated or decelerated to after vehicle i enters the induced area, is the corresponding acceleration; Indicates that when vehicle i reaches the maximum queue length position After that, it needs to accelerate to the target speed, is the corresponding acceleration;

said and The value of is calculated by the following formula:

Among them, v _t ' is a temporary velocity variable, a' is a temporary acceleration variable, t' is a temporary acceleration time variable; if there is no and but and The value is NULL;

In formula (5), ② is the condition of the ideal state, that is, the vehicle i reaches the maximum queuing length position after the queuing length reaches the maximum value in the nth arrival cycle; ③④⑤⑥ is the reasonable induced speed limit condition; ⑦ means Take the solution with the smallest absolute value among all the solutions of a';

like and is not NULL, The value of is calculated by the following formula:

Where v' _t is a temporary velocity variable, a' is a temporary acceleration variable, and t' is a temporary acceleration time variable. If there is no matching and but and The value is NULL;

In formula (6), except ②, other parts are basically consistent with formula (2); in ②, for the vehicle to time, for the vehicle from The time it takes to travel to the stop line. Take the minimum value of a' that meets the condition, for the corresponding speed.

The meaning of is the same as that of the ideal function Road(), namely Indicates speed Able to meet traffic requirements. defined as:

Preferably, said step 42 includes:

If the vehicle i travels to the boundary of the queuing range at the original speed v ₀ and the signal state is the effective red light time, then the induction scheme includes:

Option 1, if the traffic state of the arrival cycle is not oversaturated, make the arrival time conform to the ideal state of the arrival cycle;

Scheme 2, if the traffic state of the arrival cycle is not oversaturated in the previous cycle, make the arrival time conform to the ideal state of the previous cycle;

In the algorithm, it is necessary to calculate the optimal speed at which the queue length has reached the maximum value and the optimal speed at which the vehicle i travels from the maximum queue length position to the stop line when it travels to the end of the queue range. If both optimal speeds exist, it is recommended that the vehicle adjust to the optimal speed to achieve non-stop passing through the intersection; the specific algorithm is as follows:

If the traffic state of the nth arrival cycle is not supersaturated, and and are not empty, execute scheme 1; if the n-1th period is not supersaturated, and and If they are not empty, then implement the second option; if both options are feasible, then choose and The scheme corresponding to the acceleration with the smallest absolute value;

and The calculation method of is the same as formulas (5) and (6);

and The calculation method of is similar to the formulas (5) and (6), the differences are as follows:

In formula (5), formula ② becomes:

Formula ③ becomes:

In formula (6), formula ② becomes:

Formula ③ becomes:

Preferably, said step 43 includes:

When the traffic state of vehicle i's arrival cycle is supersaturated, it is necessary to detect whether the previous cycle and the next cycle are supersaturated cycles; The cycle is adjusted to the ideal state of the corresponding cycle; if the two adjacent cycles are in the normal state, the induction algorithm selects the scheme with the smallest change in the induced speed relative to the original speed;

If the traffic state of three consecutive arrival cycles is in an oversaturated state, or there is no ideal state induced speed in adjacent cycles, the purpose of the induction is to prevent vehicle i from entering the remaining queue of this cycle and prevent vehicles from experiencing oversaturation delays state, the corresponding induction strategy is: at the initial induction speed for The corresponding induction strategy is: from the boundary of the induction range to the distance from the stop line The induction strategy of the position is based on is the acceleration, which gradually accelerates or decelerates to Then drive at a constant speed until it reaches the end of the queue;

The induction algorithm is as follows:

in Indicates the target vehicle speed that needs to be accelerated or decelerated to in order not to enter the remaining queue after vehicle i enters the induction area, is the corresponding acceleration; define the wave speed of the queuing wave of the nth arrival cycle as

The induction speed Calculated by the following formula:

Among them, v' _t is a temporary velocity variable, a' is a temporary acceleration variable, t' is a temporary acceleration time variable; if there is no but and The value is NULL;

In formula (10), Indicates that the vehicle has traveled to the stop line The time of the position, at the nth arrival cycle, and less than or equal to from stop line to The position of is the part of the non-remaining queue in the queue length; is the queuing wave propagating from the stop line to The time of the position; if the vehicle reaches Arriving at the queuing queue earlier, then the oversaturation delay state can be avoided.

As shown in Figure 7, it is the crossing simulation effect diagram of the active traffic guidance method of a kind of intersection level of the present invention, and road 1 is the intersection that adopts the active traffic guidance method of a kind of intersection level of the present invention, and road 2 is the usual The intersection under the situation; It can be clearly drawn from Fig. 8 and Fig. 9 that the intersection road 1 adopting a kind of intersection-level active traffic guidance method of the present invention makes the vehicle not stop or the number of parking is stable when passing the intersection; The parking time is significantly shortened.

In summary, an intersection-level active traffic guidance method of the present invention, an intersection-level active traffic guidance method, aims to solve the problem of not stopping or shortening the parking time when vehicles pass through the intersection, thereby reducing intersection delays, Reduce traffic congestion and environmental pollution, improve driving efficiency.

Claims (10)

1. an active traffic guidance method of intersection level, is characterized in that, comprises the following steps: Step 1. Active traffic guidance strategy analysis at intersection level; Step 2, judging the traffic state of the vehicle arrival period; Step 3, judging that the speed of the vehicle is a reasonable speed standard; Step 4. According to the traffic state and signal state of the vehicle arrival cycle, implement the corresponding intersection-level active traffic guidance algorithm. 2. the active traffic guidance method of a kind of intersection level according to claim 1, is characterized in that, comprises the following steps in the described step 1: Step 11, precondition analysis, R _d represents the length of the induction area, R _q represents the length of the queuing range, when the vehicle enters the induction area and the queuing range, it communicates with the drive test equipment in real time, and provides the driving information of the vehicle to the drive test equipment, The inducing area is the range in which the vehicle speed is induced and adjusted, that is, the range from the stop line to the _upstream length R _d ; The length from the line to the upstream is R _q , and R _q < R _d ; Step 12, ideal state analysis, when the vehicle arrives at the intersection, the vehicle release state at the intersection is the green light state, that is, when the saturation of the intersection is unsaturated or quasi-saturated, the vehicle can pass through the intersection without stopping. The situation occurs after the queuing length reaches the maximum value and before the red light duration of the intersection indicator light of the next cycle begins. 3. the active traffic guidance method of a kind of intersection level according to claim 1, is characterized in that, comprises the following steps in the described step 2: Step 21. Calculate the intersection saturation through the formula, the intersection saturation is the maximum value of each phase saturation of the intersection, the formula is: Among them, x is the intersection saturation, q is the flow rate of phase-critical traffic flow, and Q is the traffic capacity; Step 22. Judging the intersection saturation state, the intersection saturation is divided into unsaturated state, quasi-saturated state and supersaturated state. When x is less than 1, it is unsaturated state; when x is equal to 1, it is quasi-saturated state state; when x is greater than 1, it is an oversaturated state; Step 23. When the intersection saturation is oversaturated, the accumulated vehicles and real-time vehicles within the accumulated time cannot be cleared within the release time. After the release time is over, the remaining vehicles will be accumulated as the accumulated vehicles for the next cycle, occupying the next cycle’s accumulated vehicles. Release time, the release time is the duration of the green light of the intersection indicator light, and the cumulative time refers to the duration of the red light of the intersection indicator light. 4. the active traffic guidance method of a kind of intersection level according to claim 1, is characterized in that, comprises the following steps in the described step 3: Step 31. Judging the vehicle speed Whether the speed limit V _lim specified by the road section is exceeded, when there is no speed limit specified by the road section, let V _lim = 80km/h; Step 32. Determine whether the acceleration is within the reasonable range [-a _MAX , a _MAX ]. The reasonable range of acceleration is different for different models: a _MAX = 5m/s ² for small cars; a _MAX = 4m/s ² for medium-sized cars ; Large vehicle a _MAX = 3m/s ² ; Step 33. Judging the vehicle speed Whether it can be accepted by the driver, the speed change cannot exceed 60% of the original speed; Step 34. Determine whether the driving conditions allow speed adjustment. The distance between vehicles in front of the vehicle needs to be able to allow the vehicle to accelerate. If the distance between vehicles cannot meet the speed requirements, it is necessary to check whether the speed can be updated by changing lanes. If neither allowed, speed It is regarded as an unreasonable induced speed. 5. the active traffic guidance method of a kind of intersection level according to claim 1, is characterized in that, comprises the following steps in the described step 4: Step 41. If the traffic state of the arrival cycle is unsaturated and the signal state of the arrival time is the effective green light time, the state of the arrival cycle is an ideal state and a non-ideal state, and corresponding induction algorithms need to be established respectively; otherwise, execute the step 42; Step 42. If the traffic state of the arrival period is unsaturated and the signal state at the arrival time is the effective red light time, vehicle i travels to the boundary of the queuing range at the initial speed v ₀ , and the signal state is still the effective red light time, which needs to be established Corresponding intersection-level active traffic guidance method; otherwise, execute step 43; Step 43. If the traffic state of the arrival cycle is oversaturated, all vehicles arriving at the intersection must stop before they can pass through the intersection. For the remaining vehicles in the queue, the waiting time also includes the effective red light of the next cycle time, that is, the oversaturation delay state, and corresponding intersection-level active traffic guidance methods need to be established. 6. The active traffic guidance method of a kind of crossing level according to claim 5, characterized in that, the effective green light time refers to the transit time that the signal phase can utilize in a signal cycle is converted into ideal utilization time. The corresponding green light release time; the effective red light time refers to the corresponding red light release time when the red light time of the signal phase within a signal cycle is converted into an ideal stop. 7. the active traffic guidance method of a kind of intersection level according to claim 5, is characterized in that, comprises in the described step 41: The ideal state is that when the vehicle i travels to the end of the queuing range at the initial speed _v0 , the queuing length has reached the maximum value, and the vehicle can pass the stop line within the remaining effective green light time, then the corresponding induction strategy is: initial induction velocity is v ₀ , from the induction range boundary R _d to the position of the maximum queue length of the arrival period The induced velocity in this interval is the original velocity v ₀ ; from to the stop line, still traveling at speed v ₀ , or at is the acceleration, and gradually accelerates to Then drive at a constant speed; each induction speed corresponds to an induction strategy; Ideally, the algorithm steps are as follows: in, Indicates the time when vehicle i travels to the boundary of the queuing range at speed v ₀ ; Indicates that the nth signal cycle is in a normal state; Indicates that when the vehicle i travels to the position of the maximum queue length, the queue length has reached the maximum value and begins to dissipate; Indicates that the time for vehicle i to reach the stop line is less than the start time of the effective red light in the next cycle, where _tl represents the time for the vehicle to travel from the position of the maximum queuing length to the stop line, if but like Then t _l is determined by the acceleration and speed after acceleration decision, said Indicates the target vehicle speed that needs to be accelerated or decelerated to after vehicle i reaches the maximum queuing area position in the nth cycle, is the corresponding acceleration, calculated by the following formula: Among them, v' _t is a temporary velocity variable, a' is a temporary acceleration variable, t' is a temporary acceleration time variable; if there is no and but and The value is NULL; In the formula (2), ② is the induced speed that meets the conditions; ③ is the limitation condition of the acceleration distance; ④ ⑤ ⑥ is the reasonable judgment standard of the induced vehicle speed; ⑦ represents Take the minimum value of all solutions in a'; in this stage, the acceleration a' is greater than or equal to 0; like and is not NULL, then Otherwise, it does not meet the conditions of the ideal state and should be treated as a non-ideal state; Road(v ₀ )>0 indicates that the speed v ₀ can meet the requirements of traffic conditions, Road(v ₀ )≤0 indicates that the current traffic state does not meet the condition of vehicle speed v ₀ , Road(v ₀ ) is defined as: d ⁺⁽ⁱ⁾ (t) indicates the distance between vehicle i and the adjacent vehicle in front at time t; d ⁺⁽ⁱ⁾ (T ₀ )≥v ₀ indicates the conditions that vehicle i needs to meet when driving in this lane at speed v ₀ ; And Indicates that vehicle i satisfies the lane change condition; Indicates the distance between vehicle i and the front and rear adjacent vehicles on the adjacent lane at time t, x can be + or -, + means the front, - means the rear; is the motivational condition for lane-changing, safety conditions for changing lanes; When vehicle i is not allowed to change lanes at will because it is close to the intersection, let the adjacent lanes that do not meet the lane change conditions 8. A kind of intersection level active traffic guidance method according to claim 5, is characterized in that, comprises in the described step 41: The non-ideal state is that when the vehicle i travels to the end of the queuing range at speed _v0 , the queuing length does not reach the maximum value, then the corresponding induction strategy is to make the arrival time conform to the ideal state of the arrival cycle, and the corresponding induction strategy is : at the initial induced velocity for From the induction range boundary to the maximum position of the queue length of the arrival period, with is the acceleration, which gradually accelerates or decelerates to driving at a constant speed; from the position with the maximum queue length to the stop line, to is the acceleration, gradually accelerating to Then drive at a constant speed; according to the time when the queue length reaches the maximum value with the length of the maximum Calculate the induced speed at which the queuing length has reached the maximum value when vehicle i travels to the end of the queue; if the induced speed exists, it is recommended that the vehicle adjust to the induced speed so as to pass through the intersection without stopping; In the non-ideal state, the algorithm steps are as follows: in, Indicates that when vehicle i travels to the position of the maximum queue length at speed v ₀ , the queue length has not yet reached the maximum value; Indicates the target vehicle speed that needs to be accelerated or decelerated to after vehicle i enters the induced area, is the corresponding acceleration; Indicates that when vehicle i reaches the maximum queue length position After that, it needs to accelerate to the target speed, is the corresponding acceleration; said and The value of is calculated by the following formula: Among them, v _t ' is a temporary velocity variable, a' is a temporary acceleration variable, t' is a temporary acceleration time variable; if there is no and but and The value is NULL; In formula (5), ② is the condition of the ideal state, that is, the vehicle i reaches the maximum queuing length position after the queuing length reaches the maximum value in the nth arrival cycle; ③④⑤⑥ is the reasonable induced speed limit condition; ⑦ means Take the solution with the smallest absolute value among all the solutions of a'; like and is not NULL, The value of is calculated by the following formula: Where v' _t is a temporary velocity variable, a' is a temporary acceleration variable, t' is a temporary acceleration time variable; if there is no and but and The value is NULL; In formula (6), except ②, other parts are basically consistent with formula (2); in ②, for the vehicle to time, for the vehicle from the time it takes to travel to the stop line; Take the minimum value of a' that meets the condition, is the corresponding speed; The meaning of is the same as that of the ideal function Road(), namely Indicates speed be able to meet the requirements of traffic conditions; defined as: 9. the active traffic guidance method of a kind of intersection level according to claim 5, is characterized in that, comprises in the described step 42: If the vehicle i travels to the boundary of the queuing range at the original speed v ₀ and the signal state is the effective red light time, then the induction scheme includes: Option 1, if the traffic state of the arrival cycle is not oversaturated, make the arrival time conform to the ideal state of the arrival cycle; Scheme 2, if the traffic state of the arrival cycle is not supersaturated in the previous cycle, make the arrival time conform to the ideal state of the previous cycle; In the algorithm, it is necessary to calculate the optimal speed at which the queuing length has reached the maximum value and the optimal speed at which the vehicle i travels from the maximum queuing length position to the stop line when the vehicle i travels to the end of the queuing range; if both optimal velocities exist, then It is recommended that vehicles adjust to the optimum speed to pass through the intersection without stopping; the specific algorithm is as follows: If the traffic state of the nth arrival cycle is not supersaturated, and and are not empty, execute plan one; if the n-1th period is not in a supersaturated state, and and If both are not empty, then plan 2 will be implemented; if both plans are feasible, then choose and The scheme corresponding to the acceleration with the smallest absolute value; and The calculation method of is the same as formulas (5) and (6); and The calculation method of is similar to the formulas (5) and (6), the differences are as follows: In formula (5), formula ② becomes: Formula ③ becomes: In formula (6), formula ② becomes: Formula ③ becomes: 10. A kind of intersection level active traffic guidance method according to claim 5, is characterized in that, comprises in the described step 43: When the traffic state of vehicle i's arrival cycle is supersaturated, it is necessary to detect whether the previous cycle and the next cycle are supersaturated cycles; The cycle is adjusted to the ideal state of the corresponding cycle; if the two adjacent cycles are in the normal state, the induction algorithm selects the scheme with the smallest change in the induced speed relative to the original speed; If the traffic state of three consecutive arrival cycles is in an oversaturated state, or there is no ideal state induced speed in adjacent cycles, the purpose of the induction is to prevent vehicle i from entering the remaining queue of this cycle and prevent vehicles from experiencing oversaturation delays state, the corresponding induction strategy is: at the initial induction speed for The corresponding induction strategy is: from the boundary of the induction range to the distance from the stop line The induction strategy of the position is based on is the acceleration, which gradually accelerates or decelerates to Then drive at a constant speed until it reaches the end of the queue; The induction algorithm is as follows: in Indicates the target vehicle speed that needs to be accelerated or decelerated to in order not to enter the remaining queue after vehicle i enters the induction area, is the corresponding acceleration; define the wave speed of the queuing wave of the nth arrival cycle as The induction speed Calculated by the following formula: Among them, v' _t is a temporary velocity variable, a' is a temporary acceleration variable, t' is a temporary acceleration time variable; if there is no but and The value is NULL; In formula (10), Indicates that the vehicle has traveled to the stop line The time of the position, at the nth arrival cycle, and less than or equal to from stop line to The position of is the part of the non-remaining queue in the queue length; is the queuing wave propagating from the stop line to The time of the position; if the vehicle reaches Arriving at the queuing queue earlier, then the oversaturation delay state can be avoided.