Summary of the invention
Undesirable effect and self-adaption cruise system and electronic vapour are obtained for traffic information in the prior art in order to overcomeExclusive traveling control model such as regenerative braking of vehicle etc. combines untight disadvantage, and the present invention provides a kind of based on vehicle connectionThe electric car adaptive cruise control system and method for net, car networking wireless communication apparatus is taken based on IEEE in the system802.15.4 the ZigBee wireless communication protocol (hereinafter referred to as Zigbee protocol) of standard realizes the license plate number of vehicle on road,Speed, the information such as position and road speed limit, the information such as gradient are shared between road and vehicle and vehicle and vehicle, electronic vapourThe self-adaption cruise system of vehicle adjusts constant speed and Car following model switching during cruise, determines most using these information as foundationOn good braking opportunity, Brake energy recovery effect is made to reach best.Vehicle in the process of moving trackside to vehicle transmit road slopeDegree, the speed of speed limit and other vehicles, position, the information such as traveling lane, vehicle transmit speed, battery charge state to trackside(hereinafter referred to as SOC value), position, driving direction, the information such as traveling lane.The front that vehicle is fed back according to self-position and tracksideVehicle location obtains the spacing of itself and front truck, is determined according to the front truck speed that itself speed, SOC value, spacing and trackside are fed backCruise mode is the opportunity of constant speed or follow the bus and the switching of both states.It is patrolled in Car following model or constant speed mode switchingIt navigates in rate process, vehicle can be pressed according to the information obtained from car networking wireless communication apparatus and the status information of itselfAccording to the strategy of setting obtain that regenerative braking result can be made to reach optimal traveling scheme.
In the present invention, have for the improvement of the background technique: the device that can be realized car networking function is completeBall positioning system (hereinafter referred to as GPS) module uses the XBee communication module of ZigBee wireless communication protocol (hereinafter referred to asXBee module), using this covering device realize car networking function, thus make due to electronic navigation system information update not in time andThe undesirable disadvantage of the excessively high acquisition effect for leading to traffic information of the cost of trailer-mounted radar sensor is avoided.It is provided by the inventionVehicle Adaptive Cruising Control Systems are designed towards electric car, regeneration brake system and battery for electric car etc.The components different from conventional fuel oil automobile account for, and can effectively save on the basis of considering driver's driver comfortElectric car energy consumption extends electric car continual mileage.
In conjunction with Figure of description, technical scheme is as follows:
A kind of electric car adaptive cruise control system based on car networking, wherein the wireless communication based on car networking fillsIt sets using the ZigBee wireless communication protocol based on IEEE 802.15.4 standard, by Vehicular device and road on hardware configurationDevice composition, Vehicular device are mounted in automobile, and road device is mounted on traffic route roadside；
The Vehicular device is by the first master control borad, the first XBee module, camera module and GPS module composition, camera shootingThe road of head module shooting vehicle current driving simultaneously identifies the lane of current driving and sends it to the first master control borad, GPSVehicle location is determined and transmitted to the first master control borad by module, and the first master control borad and vehicle CAN bus and electric car are adaptiveCruise control connection, can be by the identification of the vehicle information on automobile CAN-bus, vehicle speed information, SOC value information, and pedal is openedDegree information etc. is read out, and the first XBee module by connecting with the first master control borad sends such information to road deviceOn the 2nd XBee module, while the first XBee module of Vehicular device can also receive what the 2nd XBee module of road was sentRelevant information, and send it in electric car adaptive learning algorithms device by the first master control borad；
The road device is stored with speed limit, road by the second master control borad, the 2nd XBee module composition, the second master control borad in the middleThe roads relevant information such as road gradient, can be sent to by the 2nd XBee module on road device on traffic firstXBee module, while the 2nd XBee module on road device can also receive the correlation sent from the first XBee module of vehicleInformation, road device are also connected with cloud server, with information that real-time update is broadcasted outward and can upload what itself was receivedInformation, cloud server are connect with the second master control borad, in practical applications, there are multiple car networking road devices in car networking,Second master control borad of cloud server and each car networking road device establishes connection and transmits information mutually.
Braking system on the electric car adaptive learning algorithms device and electric automobile chassis, drive system and steeringThe controller of system is connected, and can adjust the row of electric car according to the information transmitted in car networking during running carSail state and mode.
A kind of electric car self-adapting cruise control method based on car networking, wherein the adaptive cruise mistake of electric carThere are cruises and follow the bus cruise both of which for journey.If the first XBee module of Vehicular device receives road device transmissionIn other information of vehicles come, when being greater than the set value L at a distance from the nearest vehicle in front identical with this vehicle current lane and this vehicle,Electric car adaptive learning algorithms device be considered as it is accessible in front of this lane, into cruise mode, to be determined in advanceCruising speed vcRemain a constant speed traveling.If the first XBee module of Vehicular device receives other that road device sendsIn information of vehicles, being less than or equal to setting value L at a distance from the nearest vehicle in front identical with this vehicle current lane and this vehicle (canTo be adjusted) when, at this time in order to save the time that signal transmits, shorten the delay of signal transmission, the method taken is roadDevice sends the identification of the vehicle of an other vehicle to the first XBee module above two vehicles respectively, then the first of this two carsXBee module pairs simultaneously establish wireless connection, in this way from the status information for directly sending itself between two vehicles to other side, eliminateThe step of by road device as transfer, ensure that the low latency of signal transmission.Electric car adaptive learning algorithms device at this timeCompare the cruising speed v of this vehicle settingcWith the travel speed v of front truckfSize, if vc≤vf, illustrate front truck and this vehicle spacing notIt can reduce again, still maintain cruise mode at this time, if vc> vf, illustrate if continued by travelling at this rate, Ben Che withFront truck spacing can constantly reduce until collision, switches into Car following model, this vehicle decelerates to v at this timec=vfAnd two vehicle distance simultaneouslyIt is reduced to safe distance s (s < L).
In the Car following model, in this vehicle decelerating phase, to guarantee that energy regenerating effect is most in regenerative braking moderating processIt is good, while guaranteeing driver's driver comfort, do not occur excessive braking deceleration, uses Dynamic Programming and optimal control policyDetermine the motor braking process of regenerative braking.Detailed process are as follows: process of regenerative braking is divided into several steps, preceding vehicle speedEvery generation one-shot change rate is more than limit value, then this vehicle braking process enters next step, until two vehicle speeds reach unanimously, ifIt experienced N number of such step, state variable of the setting vehicle in kth step (0 < k≤N) in totalItsMiddle v represents the initial speed under the state, and a represents braking deceleration, is obtained by pedal opening, and p represents the displacement of brake pedal,Superscript i represents i-th kind of state of this step, i=1,2 ..., M, ai=amaxI/M, M are a positive integer, and the bigger representative of M canSelective state is more, and interval division is finer；K=1 represents original state, k=N represent after braking is completed safety away fromFrom state when two vehicle speeds reach identical under s, the state variable under the two states be it is known, control strategy be in centreThe step of in, each step to next step carry out during, calculateIt arrivesThe energy recycledWherein i, j=1,2 ..., M,Maximum value therein is taken, objective function is set as
In order to guarantee the comfort of driver, it is desirable that there are a threshold values for braking deceleration, while being also that this optimization is askedThe constraint condition of topic, is expressed as
The distance that vehicle driving is crossed in entire braking process is
In this way, each step determines in objective function acquisition process when the objective function for meeting constraint condition is optimalState variable just determine automobile is travelled in braking process distance d, it is determined whether change adaptive cruise strategy instituteSpacing value L of the vehicle from this vehicle is set to recently in front of the same lane of foundation
L=d+s
Minimum safe spacing of the s between two vehicles.That is L can according to the speed of Ben Che and front truck, acceleration andLocation information etc. carries out online updating after determining follow the bus strategy in car networking environment.As described above, the follow the bus mouldIn formula, the motor braking algorithm of this vehicle decelerating phase regenerative braking can be concluded according to following algorithmic procedure:
(1) initial value of transmission range L, discretization number of states M, maximum regeneration braking deceleration amax, safe distance between vehicles s；
(2) process of regenerative braking enters first step, enables counter k=1, arrives state M to discretization state 1, successivelyCalculate corresponding state variableWherein v represents the initial speed under the state, and a represents braking deceleration, pThe displacement of brake pedal is represented, superscript i represents i-th kind of state of this step, i=1,2 ..., M；
(3) whether the vehicle speed variation rate for detecting front truck is more than then to enter (4) in this way to threshold value, otherwise enters (10)；
(4) counter k increases 1 certainly；
(5) state M is arrived to discretization state 1, successively calculates corresponding state variableWherein v is representedInitial speed under the state, a represent braking deceleration, and p represents the displacement of brake pedal, and superscript j represents the jth of this stepKind state, j=1,2 ..., M；
(6) it calculates from stateTo stateThe energy that theory is recycled
(7) calculating in (6) is takenMaximum value is ek, return (3)；
(8) N=k is enabled；
(9) this procedural theory recycling ceiling capacity is calculated
(10) k increases 1, N=k, a certainlyk-1=amax, vkEqual to front truck speed；
(11) this vehicle operating range is during this
(12) it enables L=d+s and updates the value of L in (1)；
A kind of electric car self-adapting cruise control method based on car networking, wherein road device can be to Vehicular deviceRoad speed limit and grade information are sent, specifically further includes sending road speed limit to change or occur the more specific location information in ramp,Vehicular device can determine after receiving these information this vehicle apart from road speed limit change position or rise slope position away fromFrom.If car networking system perceives front, there are the change of road speed limit and new speed limit vdLess than current cruising speed vc,Then at speed limit change distance beSentence amaxDeceleration is decelerated to vdAfterwards with vdCarry out cruise.
Compared with prior art, the beneficial effects of the present invention are:
1. a kind of electric car adaptive cruise control system and method based on car networking of the present invention uses vehicleTraffic information is transmitted in networking, and this method is different from traditional only means using Driver Vision information as judgement, letterThe range for ceasing transmission is wider, more for the information of decision；It is carried out with existing by electronic map and Vehicle radar sensorThe mode of traffic information transmitting is compared, due to the information update cost with trailer-mounted radar sensor not in time of electronic navigation systemThe undesirable disadvantage of the excessively high acquisition effect for leading to traffic information is avoided.
2. in a kind of electric car adaptive cruise control system and method based on car networking of the present invention, vehicleAdaptive cruise control system is designed towards electric car, regeneration brake system and battery for electric car etc. and biographyThe different component of system fuel-engined vehicle accounts for, and can effectively save on the basis of considering driver's driver comfort electronicAutomobile energy consumption.
3. needing to cooperate with two vehicle of front and back under adaptive cruise Car following model in the module for realizing car networking functionMatching, road device is after completing to the matching of two vehicle of front and back, it is contemplated that the timeliness of information transmission, information transmission laterIt is directly carried out between the Vehicular device of two vehicles, road device only serves supervision effect, is eliminated in this way by road device conductThe step of transfer, can reduce the delay of wireless device information transmission.
4. Car following model needs to be decelerated under the premise of guaranteeing safe distance between vehicles under conditions of this vehicle speed is greater than front truckTwo vehicle speeds are identical, electric automobile energy recovering effect considered in this stage, while considering the real-time change of front truck speedChange, the Dynamic Programming strategy of formulation real-time update and can follow the variation of front truck speed.
5. whether changing based on adaptive cruise strategy with spacing value L of the vehicle from this vehicle can recently in front of laneAccording to the speed of Ben Che and front truck, acceleration and location information etc. carry out in car networking environment online after determining follow the bus strategyIt updates.
6. in a kind of electric car adaptive cruise control system and method based on car networking of the present invention, roadDevice is connected with cloud server, therefore can carry out real-time update to the road information of the external radio broadcasting of road device.
Specific embodiment
Technical solution in order to further illustrate the present invention, in conjunction with Figure of description, a specific embodiment of the invention is such asUnder:
[embodiment 1]
Electric car adaptive cruise process regenerative brake control system based on car networking as shown in Figure 4,1 He of vehicleVehicle 2 carries out adaptive cruise traveling on road, and the cruise mode being originally under adaptive cruise, two vehiclesIt is travelled on same lane, vehicle 2 is preceding, and vehicle 1 is rear.In scene as shown in Figure 5, what top indicated is that same lane existsThere are front truck (vehicle 2) at L in front of this vehicle (vehicle 1), and the speed v of front truck2Greater than the speed v of rear car1, i.e. v2>v1。
It is placed with Vehicular device 110 on vehicle 1, is placed with Vehicular device 120 on vehicle 2, first on Vehicular device 110Master control borad 111 is respectively with camera module 113, and the first XBee module 112, GPS module 114, CAN bus and electric car are adaptiveAnswer cruise control 310 to be connected, the first master control borad 121 on Vehicular device 120 respectively with camera module 123, the first XBeeModule 122, GPS module 124, CAN bus are connected with electric car adaptive learning algorithms device 320, and the CAN bus on two vehicles is justOften work, the controller of the braking system and drive system on 310 chassis of electric car adaptive learning algorithms device on vehicle 1It is connected, the GPS module 114 on Vehicular device 110 sends location information, camera module 113 to first to the first master control borad 111Master control borad 111 sends the running car road information of shooting, thus judges the lane of automobile current driving, the CAN on vehicle 1Bus sends the current speed of electric car to the first master control borad 111, and battery status information, the information such as pedal opening, first is mainAfter controlling these information of the acquisition of plate 111, it is sent to the 2nd XBee on road device 210 by the first XBee module 112Module 212；The first XBee module 112 sends the information that received extraneous transmission comes to the first master control borad 111 simultaneously, forThe information that extraneous transmission comes for this example is the road speed limit that the 2nd XBee module 212 is sent in road device 210, the letter such as gradientCease the speed that the first XBee module is sent in the Vehicular device with other vehicles, the relevant information etc. in CAN bus.
Road device 210 is arranged in roadside, and the second master control borad 211 thereon is connected with cloud server, cloud serverThe speed-limiting messages on present road are sent to the second master control borad 211, speed-limiting messages are passed through the 2nd XBee mould by the second master control borad 211Block 212 sends the first XBee module 112 in the Vehicular device 110 on vehicular traffic 1, meanwhile, the 2nd XBee module 212 receivesThe vehicle-related information that the first XBee module 112 is sent in Vehicular device 110 on vehicular traffic 1 is stored in the second master control boradIn 211.Road device 220 be arranged in roadside, the second master control borad 221 thereon is connected with cloud server, cloud server toSecond master control borad 221 sends the speed-limiting messages on present road, and speed-limiting messages are passed through the 2nd XBee module by the second master control borad 221The first XBee module 122 on 222 pairs of vehicular traffics 2 on Vehicular device 120 is sent, meanwhile, the 2nd XBee module 222 receivedThe vehicle-related information that the oneth XBee module 122 is sent into Vehicular device 120 on vehicle 2, there are the second master control borads 221In.Second master control borad 211 and the second master control borad 221 can send the information of vehicles of storage to cloud server, and pass through cloudSecond master control borad of end server and other road devices shares these information.
The connection relationship of system as shown in figure 4, vehicle 1 and vehicle 2 have all been equipped with the electric car of the Vehicular device,Vehicle 1 is equipped with Vehicular device 110, and vehicle 2 is equipped with Vehicular device 120, and all under the cruise mode of adaptive cruise,The cruise speed of vehicle 2 is less than the cruise speed of vehicle 1, and two vehicles all travel on same lane, and vehicle 1 is due to speedDegree is faster than vehicle 2, therefore moves closer to vehicle 2.A certain moment road device 210 passes through with the Vehicular device 110 on vehicle 1ZigBee wireless communication mode, which is established, to be wirelessly connected, the Vehicular device 120 on road device 220 and vehicle 2 by ZigBee withoutLine communication modes, which are established, to be wirelessly connected, and road device 210 and 220 is due to first in real-time reception Vehicular device 110 and 120The vehicle position information and traveling lane information that XBee module 112 and 122 is sent, and the two road devices pass through cloudServer realizes information sharing in car networking environment, therefore can obtain the distance between vehicle 1 and vehicle 2, and judgeTwo vehicles traveling is on same lane out.The second master control when distance between two vehicles is reduced into certain value, on road device 210Plate 211 controls first XBee module 112 of the 2nd XBee module 212 on vehicle 1 on Vehicular device 110 and issues signal, informsThe identifier of vehicle 2；The second master control borad 221 on road device 220 controls the 2nd XBee module 222 automobile-used dress on vehicle 2The first XBee module 122 for setting 120 issues signal, informs that the identifier of vehicle 1, the Vehicular device on vehicle 1 and vehicle 2 obtainAfter the identifier of opponent vehicle, the first XBee module 112 and 122 on two cars realizes the vehicle for matching and transmitting mutually oneselfSpeed and location information.2 speed of vehicle is smaller at this time, and vehicle 2 continues to keep cruise mode constant, and the electronic vapour of vehicle 1Vehicle adaptive learning algorithms device 310 controls the driving of vehicle 1 and braking system enters adaptive cruise Car following model, and according toFlow chart 2 and process shown in Fig. 3, it is contemplated that the driver comfort of driver sets the limiting value of deceleration.If front truck at this timeSpeed continues to reduce, and since this vehicle can persistently receive the speed signal that front truck is sent, preceding vehicle speed is every to reduce one admittedlyCertainty ratio, this vehicle braking process enter next step, and counter is followed from 1, while the state variable of one deuterzooid vehicle of update is increasedThe actual speed of front truck makes the instruction of control braking, all guarantees that Brake energy recovery efficiency is best during each step.ThisThe process of sample continues to that two vehicle speeds are consistent, and at this moment the distance between two vehicles are safe distance between vehicles s, adds braking process sheetThe distance d that garage crosses obtains new L value, completes to remind switching this shape of adaptive cruise mode when distance between two vehicles is LThe update of L value in state.