阅读说明：本技术 一种基于马尔可夫模型检测驾驶员风险等级的方法 (Method for detecting risk level of driver based on Markov model ) 是由 牛世峰 董兆晨 郑佳红 付锐 郭应时 袁伟 于 2019-09-26 设计创作，主要内容包括：本发明公开了一种基于马尔可夫模型检测驾驶员风险等级的方法,本发明通过采集车辆的速度数据以及驾驶员的不同的报警类型,对驾驶行为进行判断并对驾驶员风险等级进行分类,利用训练好的马尔可夫模型对驾驶员风险等级进行识别,再利用识别结果判断驾驶员风险等级。本发明主要服务于运输企业安全管理系统,当识别到驾驶员是高风险等级的驾驶员时,可采取相应的管理培训措施,以提高其安全性。本发明的实用化可以降低因交通事故导致的人员伤亡和财产损失,提高交通系统的整体安全性。(the invention discloses a method for detecting a driver risk level based on a Markov model, which judges driving behaviors and classifies the driver risk level by acquiring speed data of a vehicle and different alarm types of a driver, identifies the driver risk level by using the trained Markov model, and judges the driver risk level by using an identification result. The invention is mainly used for a safety management system of a transportation enterprise, and when the driver is identified to be a high-risk driver, corresponding management training measures can be taken to improve the safety of the driver. The practicability of the invention can reduce the casualties and property loss caused by traffic accidents and improve the overall safety of the traffic system.)

1. A method for detecting a driver risk level based on a markov model, comprising the steps of:

acquiring speed data of a plurality of groups of drivers, and determining a driving behavior sequence and a driver risk level of the drivers according to the speed data of the drivers;

Step two, establishing a Markov model, taking the driving behaviors of the drivers with the same risk level as the input of the Markov model, and determining various parameters in the Markov model;

step three, detecting a driving behavior sequence to be identified by using the Markov model with the determined parameters;

And step four, counting the detected driving behavior sequence in a preset time period to serve as a final risk grade judgment result under the preset confidence level of the driver.

2. the markov model-based method for detecting a risk level of a driver according to claim 1, wherein the acceleration data of the vehicle is calculated from the velocity data in the first step by:

v_tVelocity at time t, v_t-1speed at time t-1, Δ t is the time interval, rootFrom GPS data acquisition of the vehicle, a_tIs the average acceleration over time t.

3. the method for detecting the risk level of the driver based on the markov model as claimed in claim 1, wherein in the step one, when the driving behavior is determined, the acceleration information of the driver is firstly analyzed according to the speed data of the driver, then the driver behavior is divided into a plurality of types according to the acceleration information, the alarming times of the driver are collected according to an alarming system built in the vehicle, and the risk level of the driver is clustered through k-means.

4. A method for detecting a risk level of a driver based on a markov model according to claim 3, wherein in the second step, the parameters of the markov model are P ═ { C, pi }, C is an observation transition matrix, and pi is an initial state matrix.

5. The method for detecting the risk level of the driver based on the Markov model as claimed in claim 1, wherein the driving behavior level to be recognized is detected by the Markov model after determining the parameters in step three, and the output result isselecting the risk level corresponding to the Markov model with the highest probability as the recognition result of the driving behavior sequence, wherein P_jThe probability with risk level j at time t;is the initial probability distribution for the risk level j,The transition probability that the driving behavior of the driver with the risk level j at the time T is k and the driving behavior of the driver at the time T +1 is l is shown, and T refers to the length of the sequence.

6. the Markov model-based method for detecting the risk level of the driver as claimed in claim 1, wherein the concrete method of the fourth step is as follows:

firstly, judging the risk level of a driver in a short time period according to the driving behavior sequence recognition result with the length of T, wherein the judgment method comprises the following steps:

Wherein the content of the first and second substances,A recognition result indicating a risk level of the driver for a short time,from low to high risk level, P₁、P₂、P₃respectively representing the probability that the risk level identified by the driving behavior sequence to be tested is from low to high through a Markov model.

And secondly, calculating the number of the three risk levels in a long time according to the judgment result of the risk level of the driver in a short time period, wherein the calculation formula is as follows:

n1 is the number of sequences identified as low risk levels over a long period of time, n2 is the number of sequences identified as medium risk levels over a long period of time, n3 is the number of sequences identified as high risk levels over a long period of time, n is the total, x_jused as a count;

Thirdly, calculating the proportion of each risk grade according to the number of the three risk grades in a long time, wherein the calculation formula is as follows:

fourthly, expressing the uncertainty of the random variable by using the information entropy, and calculating the formula as follows:

c is 1-H and represents the confidence coefficient of the risk level of the driver, and the higher the C value is, the higher the confidence coefficient is;

Fifthly, under the condition that the confidence coefficient is C, the method for judging the risk level of the driver in a long time period is as follows:

Wherein the content of the first and second substances,Indicating the driver's long-term risk level recognition result, I₁、I₂、I₃respectively representing a low risk level, a medium risk level and a high risk level.

Technical Field

The invention belongs to the field of traffic safety, and particularly relates to a method for detecting risk level of a driver based on a Markov model.

background

with the rapid development of national economy and the acceleration of urbanization process, the motor vehicle ownership and road traffic volume in China are rapidly increased, and the problem of traffic accidents is increasingly prominent. Research has shown that, the driver factors are the main causes of traffic accidents, and the drivers have different driving risk levels and different contributions to traffic accidents, so that the drivers with low risk levels may cause less or even avoid traffic accidents, and the drivers with higher risk levels may cause more serious traffic accidents. Therefore, it is important to intensively study a driver risk level identification method.

At present, existing achievements mainly aim at the assessment of the risk level of the driver for research, and few researches aim at the identification of the risk level of the driver, so that the requirements of traffic safety management cannot be met.

Disclosure of Invention

The invention aims to overcome the defects and provide a method for detecting the risk level of a driver based on a Markov model, which can identify the risk level of the driver according to different driving behaviors and provide reference for reducing the occurrence of traffic accidents.

in order to achieve the above object, the present invention comprises the steps of:

acquiring speed data of a plurality of groups of drivers, and determining a driving behavior sequence and a driver risk level of the drivers according to the speed data of the drivers;

Step two, establishing a Markov model, taking the driving behaviors of the drivers with the same risk level as the input of the Markov model, and determining various parameters in the Markov model;

step three, detecting a driving behavior sequence to be identified by using the Markov model with the determined parameters;

And step four, counting the detected driving behavior sequence in a preset time period to serve as a final risk grade judgment result under the preset confidence level of the driver.

In the first step, acceleration data of the vehicle is calculated according to the speed data, and the calculation method of the acceleration data comprises the following steps:

v_tvelocity at time t, v_t-1speed at time t-1, Δ t being the time interval, obtained from GPS data of the vehicle, a_tIs the average acceleration over time t.

in the first step, when the driving behavior is determined, firstly, the acceleration information of a driver is analyzed according to the speed data of the driver, then the driver behavior is divided into a plurality of types according to the acceleration information, the alarming times of the driver are collected according to an alarming system arranged in a vehicle, and the risk level of the driver is clustered through k-means.

In the second step, the parameters of the markov model are P ═ { C, pi }, C is the observation value transfer matrix, and pi is the initial state matrix.

In the third step, when the Markov model after determining the parameters is used for detecting the driving behavior grade to be recognized, the output result isSelecting the risk level corresponding to the Markov model with the highest probability as the recognition result of the driving behavior sequence, wherein P is_ithe probability with risk level j at time t;Is the initial probability distribution for the risk level j,The transition probability that the driving behavior of the driver with the risk level j at the time T is k and the driving behavior of the driver at the time T +1 is l is shown, and T refers to the length of the sequence.

The concrete method of the step four is as follows:

Firstly, judging the risk level of a driver in a short time period according to the driving behavior sequence recognition result with the length of T, wherein the judgment method comprises the following steps:

Wherein the content of the first and second substances,A recognition result indicating a risk level of the driver for a short time,From low to high risk level, P₁、_x2、P₃respectively representing the probability that the risk level identified by the driving behavior sequence to be tested is from low to high through a Markov model.

And secondly, calculating the number of the three risk levels in a long time according to the judgment result of the risk level of the driver in a short time period, wherein the calculation formula is as follows:

n1 is the number of sequences identified as low risk levels over a long period of time, n2 is the number of sequences identified as medium risk levels over a long period of time, n3 is the number of sequences identified as high risk levels over a long period of time, n is the total,for the recognition of the risk level of the driver in a short time, x_jUsed as a count;

thirdly, calculating the proportion of each risk grade according to the number of the three risk grades in a long time, wherein the calculation formula is as follows:

Fourthly, expressing the uncertainty of the random variable by using the information entropy, and calculating the formula as follows:

c is 1-H and represents the confidence coefficient of the risk level of the driver, and the higher the C value is, the higher the confidence coefficient is;

fifthly, under the condition that the confidence coefficient is C, the method for judging the risk level of the driver in a long time period is as follows:

wherein the content of the first and second substances,Indicating the driver's long-term risk level recognition result, I₁、I₂、I₃Respectively representing a low risk level, a medium risk level and a high risk level.

Compared with the prior art, the method and the device have the advantages that the driving behavior is judged and the risk level of the driver is classified by acquiring the speed data of the vehicle and different alarm types of the driver, the risk level of the driver is identified by using the trained Markov model, and then the risk level of the driver is judged by using the identification result. The invention is mainly used for a safety management system of a transportation enterprise, and when the driver is identified to be a high-risk driver, corresponding management training measures can be taken to improve the safety of the driver. The practicability of the invention can reduce the casualties and property loss caused by traffic accidents and improve the overall safety of the traffic system.

drawings

FIG. 1 is a diagram of a Markov model of the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

The method comprises the steps of firstly analyzing speed data of each driver, designing an acceleration index, and identifying a driving behavior sequence of the driver by using a characteristic index. And then, dividing the drivers into low-risk level drivers, medium-risk level drivers and high-risk level drivers by using the acquired alarm type of each driver and adopting a K-Means mean clustering method. The classification of the risk level of the driver is the basis of the identification of the risk level of the driver, and whether the classification is reasonable or not directly determines the success or failure of the identification algorithm. And after the Markov model is trained by using partial data, identifying the driving behavior sequence.

the driving behaviors comprise 5 types of rapid deceleration, slow deceleration, normal driving, slow acceleration and rapid acceleration.

1. Calculating the acceleration of the vehicle;

the vehicle acceleration is an average acceleration of the vehicle in a short time, and is specifically represented by formula (1).

In the formula: v. of_tvelocity at time t, v_t-1speed at time t-1, Δ t being the time interval, obtained from GPS data of the vehicle, a_tIs the average acceleration over time t.

2. Determining driving behaviors and a risk level of a driver;

The acceleration threshold for distinguishing different driving behaviors is not yet specified, and the acceleration determination and discrimination method calculated according to the formula (1) is as follows:

a_tand 1, 2, 3, 4 and 5 represent fast deceleration, slow deceleration, normal driving, slow acceleration and fast acceleration respectively for the average acceleration in the period t. The specific determination method is to take 30% of acceleration and deceleration and 70% of acceleration and deceleration as threshold values in the acceleration sequence from large to small.

Determining the risk level of the driver mainly divides the drivers into low-risk level drivers, middle-risk level drivers and high-risk level drivers by using a K-Means clustering method for different driving alarm types.

The parameters of the markov model include:

Number of states N, set of states Q ═ Q₁，q₂，...，q_N}，q₁，q₂，...，q_Nthe acceleration information category corresponding to the driver; the number of observation states M, the set of observation states is V ═ V₁，v₂，...v_M}，v₁，v₂，...v_MCorresponding to the driving behavior risk level; the observation sequence is o₁，o₂，...o_Tt is the sequence length; the observation transition probability matrix is C,Representing a risk rating of q_jIs observed by v_kConversion to v_lJ ═ 1, 2, 3; initial state distribution probability of

3. Detecting a driver risk level based on a Markov model;

Firstly, establishing a Markov model, wherein the specific method is that the driving behaviors of drivers with the same risk level are used as the input of the Markov model, the model parameters of the Markov model are solved, P is { C, pi }, C is an observation value transfer matrix, and pi is an initial state matrix.

Then, the driving behavior sequence is identified by utilizing the established model, and the output result is as follows:and selecting the risk level corresponding to the Markov model with the highest probability as the recognition result of the driving behavior sequence.

The method is characterized in that the detection result is counted in a certain time period to obtain a final risk grade judgment result of the driver under a certain confidence coefficient, and the method comprises the following steps:

judging the risk level of the driver in a short time period according to the driving behavior sequence recognition result with the length of T, wherein the judgment method is as follows (2):

in the formula (I), the compound is shown in the specification,A recognition result indicating a risk level of the driver for a short time,Respectively representing a low risk level, a medium risk level and a high risk level, P₁、P₂、P₃respectively representing the probabilities of identifying the sequence of driving behaviors to be tested as a low risk level, a medium risk level and a high risk level by a markov model.

Secondly, calculating the number of the three risk levels in a long time according to the judgment result of the risk level of the driver in a short time period, wherein the calculation formula is as follows (3):

where n1 is the number of sequences identified as low risk levels over a long period of time, n2 is the number of sequences identified as medium risk levels over a long period of time, n3 is the number of sequences identified as high risk levels over a long period of time, n is the total,is the recognition result of the risk level of the driver in a medium-short time, x_jAnd is used only as a count.

Thirdly, calculating the proportion of each risk grade according to the number of the three risk grades in a long time, wherein the calculation formula is as shown in formula (4):

in the formula, k₁、k₂、k₃Respectively representing the recognition proportions of a low risk level, a medium risk level and a high risk level in a long time period.

Fourthly, expressing the uncertainty of the random variable by using the information entropy, wherein the calculation formula is as shown in the formula (5):

let C be 1-H, which represents the confidence in the driver risk level, with higher C values giving higher confidence.

and fifthly, under the condition that the confidence is C, judging the risk level of the driver in a long time period according to the formula (6):

In the formula (I), the compound is shown in the specification,Indicating the driver's long-term risk level recognition result, I₁、I₂、I₃Respectively representing a low risk level, a medium risk level and a high risk level.

whether the identification result of the risk grade of the driver is accurate or not is possibly related to the selection of a plurality of factors, so that the applicant carries out data analysis on the division of the driving behaviors and the classification of the risk grade based on the driving actual measurement data of the driver (n is more than 30), and researches show that when the length of the detection sequence is 8, the detection result is relatively stable, so that when the model is trained and detected, the length of the selected driving behavior sequence is 8. In the identification considering the risk level of the driver over a long period of time, the present invention selects a period of time as long as 24 hours. The final recognition result is used as a reference according to the given confidence C value.

The invention trains a Markov model and detects a driving behavior sequence by dividing driving behaviors and classifying risk levels through acquiring GPS data of vehicles and different types of alarms of drivers in real time, overcomes the inaccuracy and instability of detection results based on a short period of time, considers the risk level of the driver through detection in a long period of time and gives corresponding confidence to a final recognition result. The invention is mainly used for a vehicle safety system and a transportation enterprise safety management system, the hidden danger degrees brought to traffic safety by drivers with different risk levels are different, and the transportation enterprise can reasonably carry out batch, classification and education with different degrees on the management level of the drivers, thereby reducing the accident frequency of operating vehicles, bringing convenience for the management of the transportation enterprise and improving the operation benefit of the transportation enterprise. In addition, the invention can give reasonable advice to the driving state of the driver when the driving state fluctuates for a long time, thereby improving the safety of the driver. The practicability of the invention can reduce the casualties and property loss caused by traffic accidents and improve the overall safety of the traffic system.