Pilotless automobile automatic control device and its control methodTechnical field
The present invention relates to road environment identification and detection technique field is based on, certainly more particularly to a kind of pilotless automobileDynamic control device and its control method.
Background technique
In recent years, Domestic Automotive Industry rapidly develops, and pilotless automobile reaches street corner at last, but its arrival also willBring a series of safety problems.Since pilotless automobile is controlled by computer, some emergency events in reality on road canThe erroneous judgement that can cause computer keeps pilotless automobile out of control, causes traffic accident.The representative of self-actuating brake technology at present be withSafety is leading manufacturer of Sweden Volvo, and Volvo has developed entitled City Safety system can be with Auto-Sensing to roadCenter pedestrian and vehicle, when you with not higher than 15 km/h speed when driving, this set system can help you with self-actuating brakeIt avoids collision.It is braking provided by the vehicle and brake apparatus suitable for higher speed the advantages of the present apparatus by comparisonAcceleration can adjust in real time according to the actual conditions of Ben Che and objects in front, and the smallest acceleration is used under security situation, is kept awayExempt from because vehicle deceleration it is too fast caused by rear-end collision.
Summary of the invention
The invention mainly solves the technical problem of providing a kind of pilotless automobile automatic control device and its controlling partiesMethod.
In order to solve the above technical problems, one technical scheme adopted by the invention is that: a kind of pilotless automobile is controlled automaticallyDevice processed, comprising: vehicle speed sensor, acceleration transducer, mobile lidar, embedded controller, brake apparatus and steering engine,The data that the embedded controller acquires mobile lidar are handled, and calculate steering engine beats rudder amount, the systemDynamic device and steering engine bracing wire control brake pedal, and the information that the mobile lidar is collected is around pilotless automobileDisplacement, relative velocity and the relative acceleration of object and automobile in fixed range.
In a preferred embodiment of the present invention, the information that the acceleration transducer is collected is pilotless automobileActual acceleration.
In a preferred embodiment of the present invention, the information that the speed infection proof device is collected is the vehicle of pilotless automobileSpeed.
In a preferred embodiment of the present invention, brake apparatus is brake pedal to be controlled with bracing wire, by changing using steering engineBecome the acceleration of steering engine beaten when rudder amount changes vehicle braking
In a preferred embodiment of the present invention, a kind of pilotless automobile autocontrol method, (1) described embedded controlDevice processed judges whether have object that may meet with automobile in certain distance using the data screening that radar acquires；
(2) the safe distance x of this object and automobile is calculated if having, then by calculating d-x-1, wherein d is objects in frontDisplacement for this vehicle, 1 is safe distance when stopping, and judges whether this object can meet with vehicle；
(3) it if can meet, calculates at this time in the smallest acceleration n in safe range, and control steering engine according to about nThe steering engine corresponding rudder amount of beating at this time that calculates of function make rudder so that pilotless automobile is added as the case may be with differentSpeed brake.
In a preferred embodiment of the present invention, for vehicle driving when on road, mobile lidar constantly acquires frontDisplacement d, relative velocity v, relative acceleration a of the object relative to this vehicle, while acceleration transducer is in constantly acquisition Ben ChejiaSpeed m, vehicle speed sensor are also constantly acquiring this vehicle speed v0, v0Unit is km/h, and by real-time data transmission to embeddedController, safe following distance is related with speed, so embedded controller filters out and this vehicle actual range d < v0FrontObject recycles formula x=v*v/ (2*a) to calculate the minimum range x that carving copy vehicle at this time and objects in front will not bump against, if d-(x+1) > 0 indicates that this vehicle does not need to brake at this time, starts braking process if d- (x+1) < 0, on the one hand constantly utilizes formula A=v*v/ (2*d-2) calculates at this time the smallest relative acceleration A in safe range, then calculates the due safety of this vehicle and addsSpeed n=m-a+A.
In a preferred embodiment of the present invention, for pavement behavior at this time, between acceleration n and pulse width sFunctional relation, calculation method are as follows: determine first to store this vehicle acceleration m at this time when braking process starts, be denoted as a0, then enable steering engineRudder is made with the pulse width of 1.5ms, then stores this vehicle acceleration a after first slow down1, then calculate above-mentioned letter under this pavement behaviorSeveral slope ks=(a1-a0)/1.5, so above-mentioned functional relation is pulse width s=(n-m)/k, under this pavement behavior notIt is disconnected to slow down, until braking process terminates when this vehicle of programmed decision will not bump against with objects in front.
In a preferred embodiment of the present invention, when laser radar works, transmitter is to a string of repetition periods of spatial emissionCertain high-frequency narrow-pulse, if with the presence of target in the approach of Electromagnetic Wave Propagation, laser radar can be receivedBy the reflected echo of target, since echo-signal is travelled to and fro between radar and target, it be will be late by transmitting pulse oneTime, the energy of electromagnetic wave are with light velocity propagation, if the displacement of target is R, then the distance propagated is equal to the light velocity and is multiplied by the timeIt is spaced, i.e. 2*R=c*t, in formula, R is displacement of the target to laser radar, unit m；T is that electromagnetic wave travels to and fro between target and thunderTime interval between reaching, unit s；C is the speed propagated in air, about are as follows: c=3.0*108m/s.In modern radar,Using digital ranging, i.e., the number n of counting pulse when record echo impulse reaches, according to the repetition period T for counting pulse,It is given value that echo impulse, which can be calculated, relative to exomonental delay time t=n*T, T, and measurement t actually becomesThe number n of counting pulse when echo impulse reaches is measured, so, displacement R and the relationship for counting pulse number n are R=c*n/(2*f)。
In a preferred embodiment of the present invention, the method that the measurement of target relative velocity uses Doppler shift frequency.It is mostly generalFrequency displacement is strangled to refer to when, there are when relative velocity, the carrier frequency of the echo-signal received is relative to transmitting signal between target and radarCarrier wave generate a frequency displacement, this frequency displacement is f being physically known as Doppler frequency shift, its numerical valued=2*vr/ λ, in formula,fdFor Doppler frequency shift, unit Hz；vrDiametrically speed between radar and target, unit m/s；λ is carrier wave waveLong, unit m, in most cases, Doppler frequency are in audio range, therefore to extract Doppler from receiving in signalFrequency needs the method using beat, that is, tries to take out f0And frDifference fd, for continuous-wave Doppler lidar, to takeThe difference frequency of receiving and transmitting signal frequency out needs the method using mixing, by introducing transmitting signal in receivers as benchmark electricityPressure, obtains the difference frequency voltage of transmitting-receiving frequency, i.e. Doppler frequency voltage in the output end of phase detector.Transmitter generates frequencyFor f0The constant amplitude continuous wave higher-order of oscillation, wherein most energy is mapped to space, seldom portion of energy lotus root from transmitting antenna widthReceiver inlet is closed as reference voltage, mixed transmitting signal and reception signal export after amplification in frequency mixerIts beat voltage is taken out at end, excludes wherein DC component, obtains Doppler frequency signal and be sent to terminal indicator.
In a preferred embodiment of the present invention, displacement R and relative velocity vr, by formulaIt obtains.
The beneficial effects of the present invention are: a kind of pilotless automobile automatic control device of the present invention and its control method, are fittedFor the vehicle of higher speed, and can be by detecting whether this vehicle can meet with a certain range of surrounding objects, Jin ErliWith embedded controller processing data control brake apparatus braking, pilotless automobile when reducing the road conditions for middle complexity of facing the realityBrought safety problem.
Detailed description of the invention
To describe the technical solutions in the embodiments of the present invention more clearly, make required in being described below to embodimentAttached drawing is briefly described, it should be apparent that, drawings in the following description are only some embodiments of the invention, forFor those of ordinary skill in the art, without creative efforts, it can also be obtained according to these attached drawings otherAttached drawing, in which:
Fig. 1 is the principle side of self-braking device in one preferred embodiment of pilotless automobile automatic control device of the present inventionBlock diagram；
Fig. 2 is to calculate steering engine under security situation in one preferred embodiment of pilotless automobile automatic control device of the present invention to answerThe program chart of the pulse width of input；
Fig. 3 is continuous-wave doppler laser radar base in one preferred embodiment of pilotless automobile automatic control device of the present inventionThis working principle block diagram；
Fig. 4 show the frequency spectrum of each main point in Fig. 3 continuous-wave doppler laser radar basic functional principle block diagram.
Specific embodiment
The technical scheme in the embodiments of the invention will be clearly and completely described below, it is clear that described implementationExample is only a part of the embodiments of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, this field is commonTechnical staff's all other embodiment obtained without making creative work belongs to the model that the present invention protectsIt encloses.
Please refer to Fig. 1, Fig. 2, Fig. 3 and Fig. 4, a kind of pilotless automobile automatic control device of the present invention, comprising: speedSensor, acceleration transducer, mobile lidar, embedded controller, brake apparatus and steering engine, the embedded ControlThe data that device acquires mobile lidar are handled, and calculate steering engine beats rudder amount, and the brake apparatus and steering engine are drawnLine traffic control brake pedal, the information that the mobile lidar is collected are the object around pilotless automobile in fixed rangeDisplacement, relative velocity and relative acceleration with automobile.
Preferably, the information that the acceleration transducer is collected is the actual acceleration of pilotless automobile.
Preferably, the information that the speed infection proof device is collected is the vehicle speed of pilotless automobile.
Preferably, brake apparatus is to control brake pedal with bracing wire using steering engine, and the rudder amount of beating by changing steering engine changesAcceleration when vehicle braking.
In a preferred embodiment of the present invention, a kind of pilotless automobile autocontrol method, (1) described embedded controlDevice processed judges whether have object that may meet with automobile in certain distance using the data screening that radar acquires；
(2) the safe distance x of this object and automobile is calculated if having, then by calculating d-x-1, wherein d is objects in frontDisplacement for this vehicle, 1 is safe distance when stopping, and judges whether this object can meet with vehicle；
(3) it if can meet, calculates at this time in the smallest acceleration n in safe range, and control steering engine according to about nThe steering engine corresponding rudder amount of beating at this time that calculates of function make rudder so that pilotless automobile is added as the case may be with differentSpeed brake.
Preferably, for vehicle driving when on road, mobile lidar constantly acquires position of the objects in front relative to this vehicleD, relative velocity v, relative acceleration a are moved, while acceleration transducer is constantly acquiring this vehicle acceleration m, vehicle speed sensorConstantly acquiring this vehicle speed v0, v0Unit is km/h, and by real-time data transmission to embedded controller, safe following distanceIt is related with speed, so embedded controller filters out and this vehicle actual range d < v0Objects in front, recycle formula x=V*v/ (2*a) calculates the minimum range x that carving copy vehicle at this time and objects in front will not bump against, if d- (x+1) > 0 indicates this vehicle at this timeIt does not need to brake, starts braking process if d- (x+1) < 0, on the one hand constantly calculated using formula A=v*v/ (2*d-2)The smallest relative acceleration A in safe range at this time, then calculates the due safe acceleration n=m-a+A of this vehicle.
Preferably, for pavement behavior at this time, functional relation between acceleration n and pulse width s, calculation methodAre as follows: determine first to store this vehicle acceleration m at this time when braking process starts, is denoted as a0, then enable steering engine with the pulse width of 1.5msRudder is made, then stores this vehicle acceleration a after first slow down1, then calculate slope k=(a1- of above-mentioned function under this pavement behaviorA0)/1.5, so above-mentioned functional relation is pulse width s=(n-m)/k, constantly slow down under this pavement behavior, until programDetermine that braking process terminates when this vehicle will not bump against with objects in front.
Preferably, when laser radar works, the transmitter high-frequency narrow-pulse certain to a string of repetition periods of spatial emission, such asFruit in the approach of Electromagnetic Wave Propagation with the presence of target, then laser radar can be received by target reflected timeWave, since echo-signal is travelled to and fro between radar and target, it be will be late by transmitting one time of pulse, and the energy of electromagnetic wave isWith light velocity propagation, if the displacement of target is R, then the distance propagated is equal to the light velocity and is multiplied by time interval, i.e. 2*R=c*t, formulaIn, R is displacement of the target to laser radar, unit m；T is that electromagnetic wave travels to and fro between the time interval between target and radar, singlePosition is s；C is the speed propagated in air, about are as follows: c=3.0*108m/s.In modern radar, using digital ranging, that is, rememberThe number n for recording counting pulse when echo impulse reaches, according to the repetition period T for counting pulse, so that it may calculate echo arteries and veinsPunching is given value relative to exomonental delay time t=n*T, T, when measurement t actually becomes measurement echo impulse arrivalCounting pulse number n, so, displacement R and count pulse number n relationship be R=c*n/ (2*f).
Preferably, the method that the measurement of target relative velocity uses Doppler shift frequency.Doppler frequency shift refer to when target withThere are when relative velocity between radar, the carrier frequency of the echo-signal received generates a frequency relative to the carrier wave of transmitting signalIt moves, this frequency displacement is physically being known as Doppler frequency shift, its numerical value is fd=2*vr/ λ, in formula, fdFor Doppler frequency shift,Unit is Hz；vrDiametrically speed between radar and target, unit m/s；λ is carrier wavelength, unit m, moreIn number situation, Doppler frequency is in audio range, therefore Doppler frequency needs is extracted in signal using poor from receivingThe method of bat tries to take out f0And frDifference fd, for continuous-wave Doppler lidar, to take out receiving and transmitting signal frequencyDifference frequency, need using mixing method, by introduce in receivers transmitting signal as reference voltage, in phase detectorOutput end obtain the difference frequency voltage of transmitting-receiving frequency, i.e. Doppler frequency voltage.It is f that transmitter, which generates frequency,0Constant amplitude it is continuousThe wave higher-order of oscillation, wherein most energy are mapped to space from transmitting antenna width, seldom portion of energy is coupled to receiver inputEnd is used as reference voltage, and mixed transmitting signal and reception signal take out its beat electricity after amplification, in mixer outputPressure, excludes wherein DC component, obtains Doppler frequency signal and be sent to terminal indicator.
Preferably, displacement R and relative velocity vr, by formulaIt obtains.
A kind of pilotless automobile automatic control device of the present invention and its control method solve lacking in technical solutionIt falls into, suitable for the vehicle of higher speed, and this vehicle whether can be met with a certain range of surrounding objects by detection, intoAnd embedded controller processing data control brake apparatus is utilized to brake, it reduces unmanned when the road conditions for middle complexity of facing the realitySafety problem brought by automobile.
The above description is only an embodiment of the present invention, is not intended to limit the scope of the invention, all to utilize this hairEquivalent structure or equivalent flow shift made by bright specification and accompanying drawing content is applied directly or indirectly in other relevant skillsArt field, is included within the scope of the present invention.