The stability control method virtually taken turns based on the full drive electric automobile of four-wheelTechnical field
The invention discloses a kind of stability controls of active torque distribution virtually taken turns based on the full drive electric automobile of four-wheelMethod.
Background technique
For electric car compared with conventional fuel oil automobile, electric car use cost is low, using battery as power resources, low-carbonEnvironmental protection, the impact that do not shift gears travel more smooth；Four driving wheels of the full drive electric automobile of four-wheel are by each hub motorIndependent control, the revolving speed of separately adjustable each wheel and torque improve driver to the maneuvering performance of automobile, but due toFour wheels have independent control unit, do not need to realize turning function by electric boosting steering system come auxiliary electric automobile,It does not need to realize the increase and decrease of driving moment and the change of speed by gearbox, retarder etc., does not need to pass through differential mechanismThe safety of the safety traffic of vehicle, stability is realized in the differential function for realizing left and right wheels, the perception manipulation for relying solely on driverThere are risks, it is therefore desirable to research and develop a kind of adaptive active torque distribution for the design feature of the full drive electric automobile of four-wheelStabilizing control system.
When vehicle in the process of moving, since four wheels are independently driven by four hub motors, multi-motor driving systemSystem is driven the influence for the factors such as component, the non-linear effects of control system, low attachment road surface, road conditions are rugged, can cause fourThe dynamic unbalance of a wheel can generate the generation for deviateing the dangerous phenomenon such as driving path or generation whipping of vehicle.
Summary of the invention
Goal of the invention:
The invention discloses a kind of stability controls of active torque distribution virtually taken turns based on the full drive electric automobile of four-wheelMethod.Purpose is to construct a kind of method for the full drive electric automobile torque distribution of four-wheel to solve previous existing askTopic.Corresponding torque distribution control plan is selected by the pavement state of the full drive electric automobile traveling of detection four-wheel, real-time working conditionSlightly, to keep electric car maneuverability more smooth, stability is improved.
Technical solution:
A kind of stabilitrak for the active torque distribution virtually taken turns towards the full drive electric automobile of four-wheel, the system packetInclude box of tricks (1), virtual turbin generator control system (2), the near front wheel hub motor and control system (3), off-front wheel wheel hub electricityIt is machine and control system (4), left rear wheel hub motor and control system (5), off hind wheel hub motor and control system (6), left frontTake turns wheel speed detection unit (11), off-front wheel wheel speed detection unit (12), left rear wheel wheel speed detection unit (13), off hind wheel wheel speedDetection unit (14), weighted average unit (16), ideal pose computing unit (17), error controller (18), torque distribution controlUnit (19), steering mechanism's unit (20), virtual wheel (21), numerical value conversion unit (23) and pilot control mechanism (24) processed；
Pilot control mechanism (24) connects box of tricks (1), virtual wheel and virtual turbin generator control system (2) and reasonThink attitude calculation unit (17)；The virtual wheel of box of tricks (1) connection and virtual turbin generator control system (2), the near front wheel wheel hub electricityAfter machine and control system (3), off-front wheel hub motor and control system (4), left rear wheel hub motor and control system (5) and the right sideTake turns hub motor and control system (6)；The near front wheel hub motor and control system (3), off-front wheel hub motor and control system(4), left rear wheel hub motor and control system (5) and off hind wheel hub motor and control system (6) are separately connected the near front wheel(7), off-front wheel (8), left rear wheel (9) and off hind wheel (10)；The near front wheel wheel speed detection unit (11), the detection of off-front wheel wheel speed are singleFirst (12), left rear wheel wheel speed detection unit (13) and off hind wheel wheel speed detection unit (14) correspondence the near front wheel (7), off-front wheel (8),The revolving speed for detecting respective wheel is arranged in left rear wheel (9) and off hind wheel (10)；The near front wheel wheel speed detection unit (11), off-front wheel wheelFast detection unit (12), left rear wheel wheel speed detection unit (13), off hind wheel wheel speed detection unit (14) are connected to box of tricks(1), the ideal wheel speed of four wheels and the variance analysis of actual speed of a wheel are carried out；
Virtual wheel and virtual turbin generator control system (2) connection ideal pose computing unit (17) and weighted average unit(16), ideal pose computing unit (17) connection error controller (18), error controller (18) connect torque distribution controller(19) and steering mechanism's unit (20), weighted average unit (16) and torque distribution controller (19), the near front wheel hub motor andControl system (3), off-front wheel hub motor and control system (4), left rear wheel hub motor and control system (5) and off hind wheel wheelHub motor and control system (6) are connected, and calculate the compound real-time torque that four wheels need in vehicle travel process；
The near front wheel wheel speed detection unit (11), off-front wheel wheel speed detection unit (12), left rear wheel wheel speed detection unit (13)Wheels travel speed is obtained in real time with off hind wheel wheel speed detection unit (14)；
Virtual wheel and virtual turbin generator control system (2) are changed left front when can be according to the fructufy of weighted average unit (16)The wheel speed of wheel, off-front wheel, left rear wheel, off hind wheel, and then carry out real-time torque stable allocation；
The system further includes yaw velocity detection unit (25) and side slip angle detection unit (26), yaw velocityDetection unit (25) and side slip angle detection unit (26) are connected to ideal pose unit (17), real-time judge vehicle drivingPosture situation；
Virtual wheel and virtual turbin generator control system (2) are single by virtually taking turns (21), virtual turbin generator (22) and numerical value conversionFirst (23) are constituted；Box of tricks (1) is connect with virtual wheel (21)；It is weighted and averaged unit (16) and virtual wheel (21) and virtual wheelMotor (22) connection；Virtual turbin generator (22) is connected by numerical value conversion unit (23) with box of tricks (1).
Utilize a kind of stability control system of above-mentioned active torque distribution virtually taken turns towards the full drive electric automobile of four-wheelThe implemented control method of system, it is characterised in that: this method detects electromagnetic torque using voltage, the current value of wheel traction motorInformation, when due to road conditions condition it is bad, cause the hub motor torque of some tire to become larger, the electromagnetic torque of wheel traction motorIt can increase therewith, at this point, detecting wheel speed using four wheel speed detection units, information is fed back to hub motor control system, byIt is weighted and averaged unit calculating torque value, reasonable distribution torque carries out more motors again by the given speed of box of tricks (1)Dynamic cooperation control, real time correction driving path improves the control stability of vehicle, controls the posture of vehicle；
Specifically, this method utilizes box of tricks (1), is calculated by electric car actual direction corner and actual vehicle speedThe desired speed V of four wheels out1、V2、V3、V4, the near front wheel wheel speed detection unit (11), off-front wheel wheel speed detection unit (12),The wheel speed and feedback of left rear wheel wheel speed detection unit (13) and off hind wheel wheel speed detection unit (14) real-time detection to four wheelsIt returns box of tricks (1), and then carries out error analysis, be given to the near front wheel hub motor and control system (3), off-front wheel hub motorAnd control system (4), left rear wheel hub motor and control system (5) and off hind wheel hub motor and control system (6) are turnedSquare is given, such as encounters that a certain hub motor torque is excessive, and the torque of four wheels can be passed through weighted average unit by control system(16), torque is reasonably weighted and averaged, by virtually taking turns and virtual turbin generator control system (2) is to four wheel wheel speedsAgain it is given, vehicle is made to reach safety and stability state.
Using vehicle ideal pose computing unit (17), calculated by electric car actual direction corner with actual vehicle speedVehicle driving stable ideal yaw velocity and side slip angle, vehicle are in the process of moving, real by whole vehicle model (15)When feedback data, error controller (18) analyzes data, carries out reasonable benefit/risk to vehicle by steering mechanism (20) and turnsIt adjusts to angle, reasonably the torque of the near front wheel, off-front wheel, left rear wheel, off hind wheel is carried out by torque distribution controller (19)Stablize compensation, makes up to reasonable torque distribution, travel vehicle stabilization；
Error controller uses PI control algolithm, and PI control algolithm is according to ideal yaw velocity, ideal side slip angleDeviation between practical yaw velocity, practical side slip angle, real time correction four-wheel motor driven torque, accomplished reasonYaw moment and the desired front-wheel compensation angle for thinking driving path, enable the vehicle to travel according to steering instructions.
When pavement conditions are bad or uneven road surface occur, before the near front wheel hub motor and control system (3), the right sideTake turns hub motor and control system (4), left rear wheel hub motor and control system (5) and off hind wheel hub motor and control system(6) start itself to adjust, later virtually wheel and virtually variation update Δ ω of the turbin generator control system further according to load torque*。
Ideal velocity is directly given to box of tricks (1) by given ideal car speed, normally travel；When a certain hub motorTorque becomes larger, and torque is weighted averaging unit (16) and is connected with virtual turbin generator (22), by numerical value conversion unit (23)It is connect with box of tricks (1), gives the four-wheel speed for meeting driving cycle again, vehicle is made to reach stable state.
Box of tricks (1) is by vehicle systemic velocity and steering angle, after analyzing the near front wheel, off-front wheel, left rear wheel, the right sideThe real-time perfect condition wheel speed of wheel, ideal wheel speed equation are as follows:
V1、V2、V3、V4, respectively before inside wheel speed, preceding outside wheel speed, rear outside wheel speed, rear inside wheel speed,V is spot speed in rear axle, δinFor lubrication groove corner, δoutFor foreign steamer corner, B is wheelspan, and L is wheelbase.
Virtual turbin generator can be used following relational expression to indicate,
In formula, i=1,2,3,4, respectively represent four hub motors；ωiFor the revolving speed of motor；uiIt is for amount of torque controlElectromagnetic torque；JiFor equivalent rotary inertia；biFor friction factor；S is integral.
9, the control method according to right 4, it is characterised in that: following relational expression can be used in torque distribution controller,
ΔFzbc=Fxfl-s+Fxfr-s+Fxrl-s+Fxrr-s
Δ N indicates the yaw moment of vehicle, Δ FzbcIndicate the desired zigzag tread patterns power of driver, Fxfl-s、Fxfr-s、Fxrl-s、 Fxrr-sThe respectively longitudinal force of tire target value of the near front wheel, off-front wheel, left rear wheel, off hind wheel, Fyfl-s、Fyfr-sRespectivelyFor the side force of tire target value of the near front wheel, off-front wheel.lfIndicate distance of the mass center to front axle, TfIndicate wheel torque.The near front wheelProportional with the side force of tire and corresponding ground friction circle size of off-front wheel, i.e., the pavement friction circle of corresponding tire is bigger,Then the side force of tire of its offer is bigger accordingly, it may be assumed that
Fyfl-s、Fyfr-sThe respectively side force of tire target value of the near front wheel, off-front wheel, Fzfl、FzfrRespectively the near front wheel,The tire vertical loading of off-front wheel, μ are the coefficient of friction of wheel and ground.
Torque test unit, that is, the near front wheel wheel speed detection unit (11), off-front wheel wheel speed detection unit (12), left rear wheel wheelFast detection unit (13) and off hind wheel wheel speed detection unit (14) obtain the revolving speed of four hub motors of vehicle in real time and are closedThe torque of reason distributes, and wheel lateral force is mainly provided by deflecting roller, by the longitudinal force of the first two wheel, lateral force and latter two vehicle6 parameters of longitudinal force of wheel account for the friction circle specific gravity of respective wheel most with the tire force that four tires generate as distribution targetSmall is optimal objective, constructs objective function torque optimal scheme objective function relational expression
Wherein, JsFor goal constraint function, cxfl、cxfr、cxrl、cxrrRespectively behind the near front wheel, off-front wheel, left rear wheel, the right sideThe longitudinal force weight coefficient of wheel, cyfl、cyfrThe respectively lateral force weight coefficient of the near front wheel, off-front wheel, Fzfl、Fzfr、Fzrl、FzrrThe respectively tire vertical loading of the near front wheel, off-front wheel, left rear wheel, off hind wheel,Respectively left rear wheel and off hind wheelThe maximum drive torque of hub motor, RwFor the tire radius of wheel, Fxfl-s、Fxfr-s、Fxrl-s、Fxrr-sRespectively the near front wheel, the right sideThe longitudinal force of tire target value of front-wheel, left rear wheel, off hind wheel, Fyfl-s、Fyfr-sRespectively the near front wheel, the tire of off-front wheel are lateralPower target value.(j1 to j4 is molecule, as soon as but under being written on molecule entire formula row write not, replaced respectively with j1-j4)
Box of tricks crosses the actual vehicle speed v and steering angle sigma of vehicle, using Ackermann differential method, before analysis obtains the right sideThe ideal wheel speed of wheel, the near front wheel, off hind wheel, left rear wheel.
Advantage and effect: a kind of stability control side for the active torque distribution virtually taken turns towards the full drive electric automobile of four-wheelMethod, the system include pilot control mechanism, virtual wheel, virtual turbin generator control unit, weighted average unit, the near front wheel wheel speedDetection unit, off-front wheel wheel speed detection unit, left rear wheel wheel speed detection unit, off hind wheel wheel speed detection unit, the near front wheel wheel hubMotor and control system, off-front wheel hub motor and control system, left rear wheel hub motor and control system, off hind wheel wheel hub electricityMachine and control system, yaw velocity detection unit, side slip angle detection unit, torque distribution control unit, box of tricks,Numerical value conversion unit, ideal pose computing unit, steering mechanism's unit, error controller, whole vehicle model.
The pilot control mechanism gives the steering angle of vehicle and the speed of vehicle.The near front wheel wheel speed detectionUnit, off-front wheel wheel speed detection unit, left rear wheel wheel speed detection unit, off hind wheel wheel speed detection unit, vehicle velocity measuring listIt is first to obtain Vehicle Speed in real time.The near front wheel hub motor and control system, off-front wheel hub motor and control systemWhat system, left rear wheel hub motor and control system, off hind wheel hub motor and control system were fed back to by rotation speed detection unitWheel speed can give the desired torque of four wheels.The whole vehicle model contains yaw velocity detection unit, mass center sideDrift angle detection unit can obtain vehicle attitude in real time.Described available the near front wheel of Torque test unit, off-front wheel, a left sideThe real-time given torque of rear-wheel, off hind wheel.The virtual wheel and virtual turbin generator control unit can be single according to weighted averageThe wheel speed of the near front wheel, off-front wheel, left rear wheel, off hind wheel is changed when the torque fructufy of member.The torque distribution control unitReal-time compensation can be carried out to given torque according to vehicle attitude.The box of tricks can be according to vehicle speed and steering angleDegree, analyzes the real-time perfect condition wheel speed of the near front wheel, off-front wheel, left rear wheel, off hind wheel.
The ideal pose computing unit can analyze ideal yaw angle speed according to vehicle speed and steering angleDegree and side slip angle.The error controller can be such that the true posture of vehicle and the deviation of ideal pose reduces, in turnCarry out compensated torque.Steering mechanism's unit can automatically compensate for artificially manipulating generation after error controllerThe error of steering angle.
The present invention is in vehicle travel process, when some hub motor in four-wheel traction electric machine since pavement behavior goes outThe case where existing torque improper increase, tractive force demand will be more than the torque capacity that motor may provide, and just will form wheel hubThe fever of motor, four-wheel torque is unbalance, vehicle whipping, vehicle running path deviate the dangerous phenomenon such as ideal driving path.
The characteristics of present invention independently drives for the full drive electric automobile hub motor of four-wheel, by any hub motor torqueBig dynamic disturbances are assigned to each traction electric machine of the full drive electric automobile of four-wheel by weighted average, virtual cranking wheel control systemSystem, dynamic equilibrium four-wheel torque, while stable equilibrium four-wheel wheel speed, avoid vehicle driving trace from substantially deviateing driving and refer toIt enables, improves vehicle to the tracking ability of driving instruction.
Detailed description of the invention:
Fig. 1 is the stability control overall structure block diagram for the active torque distribution that the full drive electric automobile of four-wheel is virtually taken turns.
Fig. 2 is virtual turbin generator Control system architecture block diagram.
Fig. 3 is virtual wheel and virtual turbin generator Control system architecture block diagram.
Specific implementation measure:
A kind of stabilitrak for the active torque distribution virtually taken turns towards the full drive electric automobile of four-wheel, the system packetInclude box of tricks (1), virtual turbin generator control system (2), the near front wheel hub motor and control system (3), off-front wheel wheel hub electricityIt is machine and control system (4), left rear wheel hub motor and control system (5), off hind wheel hub motor and control system (6), left frontTake turns wheel speed detection unit (11), off-front wheel wheel speed detection unit (12), left rear wheel wheel speed detection unit (13), off hind wheel wheel speedDetection unit (14), weighted average unit (16), ideal pose computing unit (17), error controller (18), torque distribution controlUnit (19), steering mechanism's unit (20), virtual wheel (21), numerical value conversion unit (23) and pilot control mechanism (24) processed；
Pilot control mechanism (24) connects box of tricks (1), virtual wheel and virtual turbin generator control system (2) and reasonThink attitude calculation unit (17)；The virtual wheel of box of tricks (1) connection and virtual turbin generator control system (2), the near front wheel wheel hub electricityAfter machine and control system (3), off-front wheel hub motor and control system (4), left rear wheel hub motor and control system (5) and the right sideTake turns hub motor and control system (6)；The near front wheel hub motor and control system (3), off-front wheel hub motor and control system(4), left rear wheel hub motor and control system (5) and off hind wheel hub motor and control system (6) are separately connected the near front wheel(7), off-front wheel (8), left rear wheel (9) and off hind wheel (10)；The near front wheel wheel speed detection unit (11), the detection of off-front wheel wheel speed are singleFirst (12), left rear wheel wheel speed detection unit (13) and off hind wheel wheel speed detection unit (14) correspondence the near front wheel (7), off-front wheel (8),The revolving speed for detecting respective wheel is arranged in left rear wheel (9) and off hind wheel (10)；The near front wheel wheel speed detection unit (11), off-front wheel wheelFast detection unit (12), left rear wheel wheel speed detection unit (13), off hind wheel wheel speed detection unit (14) are connected to box of tricks(1), the ideal wheel speed of four wheels and the variance analysis of actual speed of a wheel are carried out；
Virtual wheel and virtual turbin generator control system (2) connection ideal pose computing unit (17) and weighted average unit(16), ideal pose computing unit (17) connection error controller (18), error controller (18) connect torque distribution controller(19) and steering mechanism's unit (20), weighted average unit (16) and torque distribution controller (19), the near front wheel hub motor andControl system (3), off-front wheel hub motor and control system (4), left rear wheel hub motor and control system (5) and off hind wheel wheelHub motor and control system (6) are connected, and calculate the compound real-time torque that four wheels need in vehicle travel process；
The near front wheel wheel speed detection unit (11), off-front wheel wheel speed detection unit (12), left rear wheel wheel speed detection unit (13)Wheels travel speed is obtained in real time with off hind wheel wheel speed detection unit (14)；
Virtual wheel and virtual turbin generator control system (2) are changed left front when can be according to the fructufy of weighted average unit (16)The wheel speed of wheel, off-front wheel, left rear wheel, off hind wheel, and then carry out real-time torque stable allocation；
The system further includes yaw velocity detection unit (25) and side slip angle detection unit (26), yaw velocityDetection unit (25) and side slip angle detection unit (26) are connected to ideal pose unit (17), real-time judge vehicle drivingPosture situation；
Virtual wheel and virtual turbin generator control system (2) are single by virtually taking turns (21), virtual turbin generator (22) and numerical value conversionFirst (23) are constituted；Box of tricks (1) is connect with virtual wheel (21)；It is weighted and averaged unit (16) and virtual wheel (21) and virtual wheelMotor (22) connection；Virtual turbin generator (22) is connected by numerical value conversion unit (23) with box of tricks (1).
Utilize a kind of stability control system of above-mentioned active torque distribution virtually taken turns towards the full drive electric automobile of four-wheelThe implemented control method of system, it is characterised in that: this method detects electromagnetic torque using voltage, the current value of wheel traction motorInformation, when due to road conditions condition it is bad, cause the hub motor torque of some tire to become larger, the electromagnetic torque of wheel traction motorIt can increase therewith, at this point, detecting wheel speed using four wheel speed detection units, information is fed back to hub motor control system, byIt is weighted and averaged unit calculating torque value, reasonable distribution torque carries out more motors again by the given speed of box of tricks (1)Dynamic cooperation control, real time correction driving path improves the control stability of vehicle, controls the posture of vehicle；
Specifically, this method utilizes box of tricks (1), is calculated by electric car actual direction corner and actual vehicle speedThe desired speed V of four wheels out1、V2、V3、V4, the near front wheel wheel speed detection unit (11), off-front wheel wheel speed detection unit (12),The wheel speed and feedback of left rear wheel wheel speed detection unit (13) and off hind wheel wheel speed detection unit (14) real-time detection to four wheelsIt returns box of tricks (1), and then carries out error analysis, be given to the near front wheel hub motor and control system (3), off-front wheel hub motorAnd control system (4), left rear wheel hub motor and control system (5) and off hind wheel hub motor and control system (6) are turnedSquare is given, such as encounters that a certain hub motor torque is excessive, and the torque of four wheels can be passed through weighted average unit by control system(16), torque is reasonably weighted and averaged, by virtually taking turns and virtual turbin generator control system (2) is to four wheel wheel speedsAgain it is given, vehicle is made to reach safety and stability state.
Using vehicle ideal pose computing unit (17), calculated by electric car actual direction corner with actual vehicle speedVehicle driving stable ideal yaw velocity and side slip angle, vehicle are in the process of moving, real by whole vehicle model (15)When feedback data, error controller (18) analyzes data, carries out reasonable benefit/risk to vehicle by steering mechanism (20) and turnsIt adjusts to angle, reasonably the torque of the near front wheel, off-front wheel, left rear wheel, off hind wheel is carried out by torque distribution controller (19)Stablize compensation, makes up to reasonable torque distribution, travel vehicle stabilization；
Error controller uses PI control algolithm, and PI control algolithm is according to ideal yaw velocity, ideal side slip angleDeviation between practical yaw velocity, practical side slip angle, real time correction four-wheel motor driven torque, accomplished reasonYaw moment and the desired front-wheel compensation angle for thinking driving path, enable the vehicle to travel according to steering instructions.
When pavement conditions are bad or uneven road surface occur, before the near front wheel hub motor and control system (3), the right sideTake turns hub motor and control system (4), left rear wheel hub motor and control system (5) and off hind wheel hub motor and control system(6) start itself to adjust, later virtually wheel and virtually variation update Δ ω of the turbin generator control system further according to load torque*。
Ideal velocity is directly given to box of tricks (1) by given ideal car speed, normally travel；When a certain hub motorTorque becomes larger, and torque is weighted averaging unit (16) and is connected with virtual turbin generator (22), by numerical value conversion unit (23)It is connect with box of tricks (1), gives the four-wheel speed for meeting driving cycle again, vehicle is made to reach stable state.
Box of tricks (1) is by vehicle systemic velocity and steering angle, after analyzing the near front wheel, off-front wheel, left rear wheel, the right sideThe real-time perfect condition wheel speed of wheel, ideal wheel speed equation are as follows:
V1、V2、V3、V4, respectively before inside wheel speed, preceding outside wheel speed, rear outside wheel speed, rear inside wheel speed,V is spot speed in rear axle, δinFor lubrication groove corner, δoutFor foreign steamer corner, B is wheelspan, and L is wheelbase.
Virtual turbin generator can be used following relational expression to indicate,
In formula, i=1,2,3,4, respectively represent four hub motors；ωiFor the revolving speed of motor；uiIt is for amount of torque controlElectromagnetic torque；JiFor equivalent rotary inertia；biFor friction factor；S is integral.
Following relational expression can be used in torque distribution controller,
ΔFzbc=Fxfl-s+Fxfr-s+Fxrl-s+Fxrr-s
Δ N indicates the yaw moment of vehicle, Δ FzbcIndicate the desired zigzag tread patterns power of driver, Fxfl-s、Fxfr-s、Fxrl-s、 Fxrr-sThe respectively longitudinal force of tire target value of the near front wheel, off-front wheel, left rear wheel, off hind wheel, Fyfl-s、Fyfr-sRespectivelyFor the side force of tire target value of the near front wheel, off-front wheel.lfIndicate distance of the mass center to front axle, TfIndicate wheel torque.The near front wheelProportional with the side force of tire and corresponding ground friction circle size of off-front wheel, i.e., the pavement friction circle of corresponding tire is bigger,Then the side force of tire of its offer is bigger accordingly, it may be assumed that
Fyfl-s、Fyfr-sThe respectively side force of tire target value of the near front wheel, off-front wheel, Fzfl、FzfrRespectively the near front wheel,The tire vertical loading of off-front wheel, μ are the coefficient of friction of wheel and ground.
Torque test unit, that is, the near front wheel wheel speed detection unit (11), off-front wheel wheel speed detection unit (12), left rear wheel wheelFast detection unit (13) and off hind wheel wheel speed detection unit (14) obtain the revolving speed of four hub motors of vehicle in real time and are closedThe torque of reason distributes, and wheel lateral force is mainly provided by deflecting roller, by the longitudinal force of the first two wheel, lateral force and latter two vehicle6 parameters of longitudinal force of wheel account for the friction circle specific gravity of respective wheel most with the tire force that four tires generate as distribution targetSmall is optimal objective, constructs objective function torque optimal scheme objective function relational expression
Wherein, JsFor goal constraint function, cxfl、cxfr、cxrl、cxrrRespectively behind the near front wheel, off-front wheel, left rear wheel, the right sideThe longitudinal force weight coefficient of wheel, cyfl、cyfrThe respectively lateral force weight coefficient of the near front wheel, off-front wheel, Fzfl、Fzfr、Fzrl、FzrrThe respectively tire vertical loading of the near front wheel, off-front wheel, left rear wheel, off hind wheel,Respectively left rear wheel and off hind wheelThe maximum drive torque of hub motor, RwFor the tire radius of wheel, Fxfl-s、Fxfr-s、Fxrl-s、Fxrr-sRespectively the near front wheel, the right sideThe longitudinal force of tire target value of front-wheel, left rear wheel, off hind wheel, Fyfl-s、Fyfr-sRespectively the near front wheel, the tire of off-front wheel are lateralPower target value；
Box of tricks crosses the actual vehicle speed v and steering angle sigma of vehicle, using Ackermann differential method, before analysis obtains the right sideThe ideal wheel speed of wheel, the near front wheel, off hind wheel, left rear wheel.
It is described in detail with reference to the accompanying drawing:
As shown in figure, the full drive electric automobile of four-wheel virtually takes turns active torque distribution control system, including box of tricks(1), the desired speed V of four wheels is calculated by electric car actual direction corner and actual vehicle speed1、 V2、V3、V4, leftFront-wheel wheel speed detection unit (11), off-front wheel wheel speed detection unit (12), left rear wheel wheel speed detection unit (13), off hind wheel wheel speedDetection unit (14) real-time detection to four wheels wheel speed and feed back to box of tricks (1), and then carry out error analysis, be given toThe near front wheel hub motor and control system (3), off-front wheel hub motor and control system (4), left rear wheel hub motor and controlSystem (5), off hind wheel hub motor and control system (6) carry out torque reference, and it is excessive such as to encounter a certain hub motor torque, controlSystem processed can reasonably be weighted and averaged torque, pass through void by the torque of four wheels by weighted average unit (16)Quasi- wheel and virtual turbin generator control system (2) give four wheel wheel speeds again, and vehicle is made to reach safety and stability state.
As shown in Figure 1, including vehicle ideal pose computing unit (17), pass through electric car actual direction corner and realitySpeed calculates the stable ideal yaw velocity and side slip angle of vehicle driving, and vehicle in the process of moving, passes through vehicleModel (15) real-time feedback data, error controller (18) analyze data, are carried out by steering mechanism (20) vehicleReasonable benefit/risk steering angle adjustment, by torque distribution controller (19) reasonably to the near front wheel, off-front wheel, left rear wheel, off hind wheelTorque carry out stablizing compensation, make up to reasonable torque distribution, travel vehicle stabilization.
As shown in Fig. 2, the control action for designing virtual turbin generator controller will lag behind the control action of electric machine controller,So asynchronous hub motor direct Torque Control starts itself when pavement conditions are bad or uneven road surface occurIt adjusts, master controller updates ω further according to the variation of load torque laterf.So by rotary inertia JfBigger value is adjusted into,Peak current can be avoided the occurrence of, guarantees that inverter works in safety zone.
As shown in figure 3, the full drive electric automobile of four-wheel virtually takes turns control system of machine, ideal car speed, normal row are givenIt sails and ideal velocity is directly given to box of tricks (1)；When a certain hub motor torque becomes larger, torque is weighted averaging unit(16) it is connected with virtual turbin generator (22), is connect by numerical value conversion unit (23) with box of tricks (1), gives and meet againThe four-wheel speed of driving cycle, makes vehicle reach stable state.
To sum up, based in the past there are the problem of, the present invention proposes a kind of master virtually taken turns based on the full drive electric automobile of four-wheelThe stability control method of dynamic torque distribution, active torque distribution can according to the pavement state of vehicle driving, driving cycle comeCorresponding torque distribution controller is selected, torque distribution controller can realize weighted average torque and be turned by target algorithmSquare dispensing controller reasonable compensation torque improves Vehicular turn performance, it is ensured that the vehicle moment is in good stability region fortuneRow.Accelerating ability is improved, guarantees the ability that vehicle steadily crosses low attachment or more complicated pavement conditions.Improve active safetyCan, lateral traction will not be caused to decline rapidly due to wheel slip and lose directional stability and handling maneuver ability, make to leadDynamic deterioration of safety.Therefore, under the premise of meeting driver to driving force demand, it is best to reach vehicle performance, and by turningSquare coordinated control system has great importance to enrich and improve active safety system.