CN104108386A - Method and device for improving running stability of vehicles - Google Patents

Abstract

The invention relates to electronic control technologies for vehicles, in particular to a method and a device for improving the stability of vehicles when the vehicles run uphill and downhill. The method for improving the running stability of the vehicles in an embodiment of the invention includes steps of correcting apparent acceleration of the vehicles by the aid of kinetic parameters of the vehicles; determining whether the vehicles are in uphill running states and downhill running states or not according to corrected values of the apparent acceleration; improving the dynamic control intervention sensitivity of the vehicles if the vehicles are in the uphill running states or the downhill running states.

Description

Improve the method and apparatus of vehicle run stability

Technical field

The present invention relates to auto electronic control technology, particularly improve the method and apparatus of vehicle stability when uphill/downhill travels.

Background technology

Ovdersteering (oversteer) is to weigh the major criterion of vehicle performance balance with understeer (understeer), the former shows as the dynamic corresponding input that is greater than chaufeur of Vehicle Driving Cycle, and the latter shows as the dynamic corresponding input that turns to that is less than chaufeur of Vehicle Driving Cycle, the cause of the two all comes from the contact force on front and back wheel tire and ground and the difference of vehicle centnifugal force.

Above-mentioned two situations all can cause vehicle unstability, particularly when Vehicle Driving Cycle for example, on the steeper gradient road surface when (mountain road with a varied topography).Particularly, when vehicle is during in up-hill journey state, owing to will overcoming self gravitation, easily cause understeer, and when in descending form state, due to the impact of acceleration due to gravity, easily cause ovdersteering, these situations all make traffic safety face great threat.

As can be seen here, in the urgent need to a kind of Vehicular turn for uphill/downhill motoring condition, stablize control technology.Yet up to now, industry not yet provides reliable, ripe scheme to solve above-mentioned technical matters.

Summary of the invention

The object of this invention is to provide a kind of method that improves vehicle run stability, particularly can improve the stability of vehicle when uphill/downhill travels.

Method according to the raising vehicle run stability of one embodiment of the invention comprises the following steps:

Utilize the kinetic parameter of described vehicle to revise the apparent acceleration/accel of described vehicle;

According to the correction of described apparent acceleration/accel, determine that whether described vehicle is in ascents and descents motoring condition;

If described vehicle, in going up a slope or descent run state, improves described vehicle dynamic and controls the sensitivity of intervening.

In the above-described embodiments, utilize kinetic parameter to realize automatic, the real-time judge of vehicle running state, improved thus the stability of Vehicle Driving Cycle and the reliability of control process.This is useful especially in occasion with a varied topography.

Preferably, in said method, when described vehicle is during in non-braking mode, revise according to the following formula the correction of described acceleration/accel: the court of a feudal ruler

$A=a_x-W_x-R_x-\frac{\mathrm{MMotAct}\×i_x}{r\×M}$

Wherein, the correction that A is apparent acceleration/accel, a _xfor apparent acceleration/accel, W _xfor air draught, R _xfor surface resistance, MMotAct is engine torque, i _xfor change speed gear box transmitting ratio, r is radius of wheel, and M is vehicle weight.

Preferably, in said method, when described vehicle is during in braking mode, revise according to the following formula the correction of described acceleration/accel:

$A=a_x-W_x-R_x-\frac{\mathrm{MMotAct}\×i_x}{r\×M}+\frac{\mathrm{Cp}\_\mathrm{FA}\×(P_{\mathrm{FL}}+P_{\mathrm{FR}})+\mathrm{Cp}\_\mathrm{RA}\×(P_{\mathrm{RL}}+P_{\mathrm{RR}})}{r\×M}$

Wherein, the correction that A is apparent acceleration/accel, a _xfor apparent acceleration/accel, W _xfor air draught, R _xfor surface resistance, MMotAct is engine torque, i _xfor change speed gear box transmitting ratio, r is radius of wheel, and M is vehicle weight, and CP_FA and CP_RA are respectively the brake efficiency of front-wheel and trailing wheel, P _fLand P _fRbe respectively the brake-pressure of front revolver and front right wheel, P _rLand P _rRbe respectively the brake-pressure of rear revolver and rear right wheel.

Preferably, in said method, by regularly or aperiodically determining according to the following formula described vehicle weight:

$M\left(t\right)=\frac{\mathrm{MMotAct}\left(t\right)\×i_x\left(t\right)}{r\×a_x\left(t\right)}$

Wherein, M (t) is t vehicle weight constantly, a _x(t) be t apparent acceleration/accel constantly, MMotAct (t) is t engine torque constantly, i _x(t) be t change speed gear box transmitting ratio constantly, r is radius of wheel.

Preferably, in said method, according to following manner, determine that whether described vehicle is in going up a slope or descent run state:

If the acceleration pedal of described vehicle is not applied to the correction of application force and described apparent acceleration/accel and continues for some time and be less than first threshold, determine that described vehicle is in up-hill journey state;

If correction that the acceleration pedal of described vehicle is not applied to application force and described apparent acceleration/accel detected, continue for some time and be greater than Second Threshold, determine that described vehicle is in descent run state,

Wherein, described first threshold is less than Second Threshold.

Preferably, in said method, according to following manner, determine that whether described vehicle is in going up a slope or descent run state:

If the acceleration pedal of described vehicle detected, be applied in application force, the correction that the drive wheel slippage degree of described vehicle is less than the 3rd threshold value and described apparent acceleration/accel continues for some time and is less than first threshold, determines that described vehicle is in up-hill journey state;

If the acceleration pedal of described vehicle detected, be applied in application force, the correction that the drive wheel slippage degree of described vehicle is less than the 3rd threshold value and described apparent acceleration/accel continues for some time and is greater than Second Threshold, determine that described vehicle is in descent run state

Wherein, described first threshold is less than Second Threshold.

Preferably, in said method, according to following manner, determine that whether described vehicle is in going up a slope or descent run state:

If the brake pedal of described vehicle detected, be applied in application force, the correction that the drive wheel slippage degree of described vehicle is less than the 3rd threshold value and described apparent acceleration/accel continues for some time and is less than first threshold, determines that described vehicle is in up-hill journey state;

If the brake pedal of described vehicle detected, be applied in application force, the correction that the drive wheel slippage degree of described vehicle is less than the 3rd threshold value and described apparent acceleration/accel continues for some time and is greater than Second Threshold, determine that described vehicle is in descent run state

Wherein, described first threshold is less than Second Threshold.

Preferably, in said method, determine according to the following formula the slippage degree of drive wheel:

$\mathrm{\λ}\left(t\right)=\frac{V\left(t\right)-V_{\mathrm{wheel}}\left(t\right)}{V\left(t\right)}$

Wherein, λ (t) is t slippage degree constantly, and V (t) is t car speed constantly, V _wheel(t) be t drive wheel rotating speed constantly.

Another object of the present invention is to provide a kind of electronic control unit, and it can improve the stability of Vehicle Driving Cycle, the particularly vehicle stability when uphill/downhill travels.

According to the electronic control unit of one embodiment of the invention, comprise input block, output unit and the control unit being coupled with described input block and output unit, wherein, described input block is configured to the detection signal of receiving sensor, described control unit is configured to generate control signal and to actuating unit, export control signal through described output unit according to the kinetic parameter of vehicle, wherein, described control unit is further configured to the stability of controlling Vehicle Driving Cycle according to following manner:

Utilize described kinetic parameter to revise the apparent acceleration/accel of described vehicle;

According to the correction of described apparent acceleration/accel, determine that whether described vehicle is in ascents and descents motoring condition; And

If described vehicle, in going up a slope or descent run state, improves described vehicle dynamic and controls the sensitivity of intervening.

Accompanying drawing explanation

Above-mentioned and/or other side of the present invention and advantage become the description of the various aspects by below in conjunction with accompanying drawing more clear and are easier to understand, and in accompanying drawing, same or analogous unit adopts identical label to represent, accompanying drawing comprises:

Fig. 1 shows an application schematic diagram that improves vehicle run stability by electronic control unit.

Fig. 2 is according to the schematic diagram of the electronic control unit of one embodiment of the invention.

Fig. 3 is according to the diagram of circuit of the method for the raising vehicle run stability of one embodiment of the invention.

Reference list

10 electronic control units

110 input blocks

120 output units

130 control units

131 I/O interfaces

132 central process units

133 memory devices 133

20 sensor groups

21 steering angle sensors

22 yaw ratio sensors

23 wheel speed sensors

30 automobile engine management systems

40 hydraulic pressure units

50 brake equipments

60 wheels

The specific embodiment

By accompanying drawing, specifically describe embodiments of the invention below.

Fig. 1 shows an application schematic diagram that improves vehicle run stability by electronic control unit.

As shown in Figure 1, electronic control unit 10 is coupled to receive with sensor group 20 Vehicular status signal detecting.Exemplarily, sensor group 20 comprises steering angle sensor 21, yaw ratio sensor 22 and wheel speed sensors 23.Electronic control unit 10 is also coupled with automobile engine management system (EMS) 30 and hydraulic pressure unit 40, they are controlled according to vehicle power mathematic(al) parameter.Under the control of electronic control unit 10, hydraulic pressure unit 50 brake activation devices 50 are to realize the braking of wheel 60.

Fig. 2 is according to the schematic diagram of the electronic control unit of one embodiment of the invention, and it can be used for the application scenarios shown in Fig. 1.

As shown in Figure 2, electronic control unit 10 comprises input block 110, output unit 120 and control unit 130.

The various sensors of input block 110 from vehicle receive detection signal and offer control unit 130.These detection signals can adopt the form of digital signal or analog signal.Control unit 130 and input block 110 and output unit 120 couplings, its kinetic parameter according to vehicle generates control signal and exports actuating unit to through output unit 120, realizes thus the control of electronic control unit to vehicle running state.

Referring to Fig. 2, control unit 130 comprises I/O interface 131, central process unit 132 and memory device 133.The detection signal that input block 110 receives can be delivered to central process unit 132 and memory device 133 through I/O interface 131.On the other hand, the control command that central process unit 132 generates also can be sent to output unit 120 through I/O interface.Required program and the data of vehicle running state are controlled in memory device 133 storages.

In the present embodiment, control unit 130 utilizes storage inside and/or the vehicle power mathematic(al) parameter that provided by external sensor is revised the apparent acceleration/accel of vehicle, and according to the correction of apparent acceleration/accel, determines the motoring condition (that is to say no in ascents and descents motoring condition) of vehicle." apparent acceleration/accel " described here refers to vehicle along the acceleration/accel of direct of travel, and it can for example, record by the sensor on vehicle (yaw ratio sensor).State parameter is such as including but not limited to the position of radius of wheel, vehicle weight, roadlock coefficient, air resistance coefficient, acceleration pedal and brake pedal or applied pressure, wheel speed, wheel braking efficiency and brake-pressure, apparent acceleration/accel and engine torque etc. on it.If judgement vehicle is in going up a slope or descent run state, control unit 130 is controlled the sensitivity of intervening by improving to vehicle dynamic.

Below describe control unit 130 and revise the concrete grammar of apparent acceleration/accel.

According to the present embodiment, for vehicle, in non-automatic state and braking mode, adopt different algorithms to revise apparent acceleration/accel.Particularly, when vehicle is during in non-braking mode, (1) revises the correction of acceleration/accel according to the following formula:

$A=a_x-W_x-R_x-\frac{\mathrm{MMotAct}\×i_x}{r\×M}---\left(1\right)$

Wherein, the correction that A is apparent acceleration/accel, a _xfor apparent acceleration/accel, W _xfor air draught, R _xfor surface resistance, MMotAct is engine torque, i _xfor change speed gear box transmitting ratio, r is radius of wheel, and M is vehicle weight.

When vehicle is during in braking mode, (2) revise the correction of acceleration/accel according to the following formula:

$A=a_x-W_x-R_x-\frac{\mathrm{MMotAct}\×i_x}{r\×M}+\frac{\mathrm{Cp}\_\mathrm{FA}\×(P_{\mathrm{FL}}+P_{\mathrm{FR}})+\mathrm{Cp}\_\mathrm{RA}\×(P_{\mathrm{RL}}+P_{\mathrm{RR}})}{r\×M}---\left(2\right)$

Wherein, the correction that A is apparent acceleration/accel, a _xfor apparent acceleration/accel, W _xfor air draught, R _xfor surface resistance, MMotAct is engine torque, i _xfor change speed gear box transmitting ratio, r is radius of wheel, and M is vehicle weight, and CP_FA and CP-RA are respectively the brake efficiency of front-wheel and trailing wheel, P _fLand P _fRbe respectively the brake-pressure of front revolver and front right wheel, P _rLand P _rRbe respectively the brake-pressure of rear revolver and rear right wheel.

Air draught W _xcan determine according to the air resistance coefficient of the speed of a motor vehicle and vehicle, and surface resistance R _xcan test reckoning by road conditions.

The load-carrying of vehicle is generally dynamic change.In the present embodiment, in order accurately to follow the tracks of this variation, can be regularly or (for example, when each vehicle start) upgrades vehicle weight according to the following formula aperiodically value:

$M\left(t\right)=\frac{\mathrm{MMotAct}\left(t\right)\×i_x\left(t\right)}{r\×a_x\left(t\right)}---\left(3\right)$

Wherein, M (t) is t vehicle weight constantly, a _x(t) be t apparent acceleration/accel constantly, MMotAct (t) is t engine torque constantly, i _x(t) be t change speed gear box transmitting ratio constantly, r is radius of wheel.

The vehicle weight calculating is for example stored in memory device 133 and calls when calculating the correction of apparent acceleration/accel for central process unit 132.

In addition, when the vehicle weight calculating according to formula (3) also can be used to judge whether vehicle exists fault or potential safety hazard.Particularly, when the average weight of the vehicle weight of calculating and vehicle (being also the fully loaded aviation value with light mass of vehicle), compare and depart from when larger, control unit 130 judges that vehicles may exist fault (for example sensor fault) or potential safety hazard and start corresponding handler.

The concrete grammar of control unit 130 judgement vehicle running states is below described.

In the present embodiment, according to the combination of the state of vehicle accelerator pedal and brake pedal, adopt corresponding criterion to determine the motoring condition of vehicle.Particularly, when vehicle is not when Free-rolling state (now the acceleration pedal of vehicle and brake pedal are all pressed), adopt following criterion to judge:

Criterion 1: if the correction of the apparent acceleration/accel calculating according to formula (1) is T in length ₁time period in be less than constantly first threshold A ₁, determine that vehicle is in up-hill journey state;

Criterion 2: if if the correction of the apparent acceleration/accel calculating according to formula (1) is T in length ₁time period in be greater than constantly Second Threshold A ₂, determine that vehicle is in descent run state.

When vehicle is when Speed-Increase State (now the acceleration pedal of vehicle is applied in application force), adopt following criterion to judge:

Criterion 3: if the drive wheel slippage degree of vehicle is less than the 3rd threshold value and the correction of the apparent acceleration/accel that calculates according to formula (1) is T in length ₂time period in be less than constantly first threshold, determine that vehicle is in up-hill journey state;

Criterion 4: if the drive wheel slippage degree of vehicle is less than the 3rd threshold value and the correction of the apparent acceleration/accel that calculates according to formula (1) is T in length ₂time period in be greater than constantly Second Threshold, determine that described vehicle is in descent run state.

When vehicle is when braking mode (now the brake pedal of vehicle is applied in application force), adopt following criterion to judge:

Criterion 5: if the drive wheel slippage degree of vehicle is less than the 3rd threshold value and the correction of the apparent acceleration/accel that calculates according to formula (2) is T in length ₃time period in be less than constantly first threshold, determine that vehicle is in up-hill journey state;

Criterion 6: if the drive wheel slippage degree of vehicle is less than the 3rd threshold value and the correction of the apparent acceleration/accel that calculates according to formula (2) is T in length ₃time period in be greater than constantly Second Threshold, determine that vehicle is in descent run state.

First threshold in above-mentioned criterion and Second Threshold can be determined suitable numerical value according to experiment, and the former is less than the latter.In addition, the length T of above-mentioned time period ₁, T ₂and T ₃can be identical, also can difference, for example T ₁can value be 1 second, T ₂and T ₃can value it be 0.5 second.

In the present embodiment, in order to follow the tracks of the dynamic change of drive wheel slippage degree, calculate according to the following formula drive wheel slippage degree:

$\mathrm{\λ}\left(t\right)=\frac{V\left(t\right)-V_{\mathrm{wheel}}\left(t\right)}{V\left(t\right)}---\left(4\right)$

Wherein, λ (t) is t slippage degree constantly, and V (t) is t car speed constantly, V _wheel(t) be t drive wheel rotating speed constantly.Above-mentioned the 3rd threshold value can value be for example-0.02.

When control unit 130 is determined vehicle in upward slope or descent run state, improve vehicle dynamic and control the sensitivity of intervening.For example, when in up-hill journey state, by current understeer being intervened to threshold value, be multiplied by one and be less than 1 coefficient and realize the raising of intervening sensitivity.And for example when in descent run state, by current ovdersteering being intervened to threshold value, be multiplied by one and be less than 1 coefficient and realize the raising of intervening sensitivity.The span of this coefficient for example can be between 0.6-0.8, and concrete numerical value depends on the degree of understeer or ovdersteering.

Fig. 3 is according to the diagram of circuit of the method for the raising vehicle run stability of one embodiment of the invention.For the purpose of setting forth conveniently, suppose to realize the method for the present embodiment here on the electronic control unit shown in Fig. 1 and 2.But it is pointed out that principle of the present invention is not limited to the control setup of particular type and structure.

As shown in Figure 3, in step S310, electronic control unit 10 obtains and calculates the required kinetic parameter of the apparent acceleration/accel of vehicle.These state parameters can obtain or from memory calls from sensor group 20.

Perform step subsequently S320, electronic control unit 10 calculates the correction of the apparent acceleration/accel of vehicle according to the kinetic parameter obtaining.Particularly, it can be for vehicle in non-braking mode and braking mode, and shown in employing formula (1) and (2), different algorithms is revised apparent acceleration/accel.

Then enter step S330, the motoring condition of electronic control unit 10 judgement vehicles.For example can utilize criterion recited above to determine whether one of them state in up-hill journey and descent run of vehicle.If judgment result is that very, proceed to step S340, otherwise process ends.

In step S340, electronic control unit 10 improves vehicle dynamic according to mode described above and controls the sensitivity of intervening.

Although represented and aspects more of the present invention be discussed, but those skilled in the art are to be appreciated that and can change aspect above-mentioned under the condition that does not deviate from the principle of the invention and spirit, therefore scope of the present invention will be limited by claim and the content that is equal to.

Claims (10)

1. a method that improves vehicle run stability, is characterized in that, comprises the following steps:

Utilize the kinetic parameter of described vehicle to revise the apparent acceleration/accel of described vehicle;

According to the correction of described apparent acceleration/accel, determine that whether described vehicle is in ascents and descents motoring condition; And

If described vehicle, in going up a slope or descent run state, improves described vehicle dynamic and controls the sensitivity of intervening.

2. the method for claim 1, wherein when described vehicle is during in non-braking mode, revise according to the following formula the correction of described acceleration/accel:

$A=a_x-W_x-R_x-\frac{\mathrm{MMotAct}\×i_x}{r\×M}$

Wherein, the correction that A is apparent acceleration/accel, a _xfor apparent acceleration/accel, W _xfor air draught, R _xfor surface resistance, MMotAct is engine torque, i _xfor change speed gear box transmitting ratio, r is radius of wheel, and M is vehicle weight.

3. the method for claim 1, wherein when described vehicle is during in braking mode, revise according to the following formula the correction of described acceleration/accel:

$A=a_x-W_x-R_x-\frac{\mathrm{MMotAct}\×i_x}{r\×M}+\frac{\mathrm{Cp}\_\mathrm{FA}\×(P_{\mathrm{FL}}+P_{\mathrm{FR}})+\mathrm{Cp}\_\mathrm{RA}\×(P_{\mathrm{RL}}+P_{\mathrm{RR}})}{r\×M}$

Wherein, the correction that A is apparent acceleration/accel, a _xfor apparent acceleration/accel, W _xfor air draught, R _xfor surface resistance, MMotAct is engine torque, i _xfor change speed gear box transmitting ratio, r is radius of wheel, and M is vehicle weight, and CP_FA and CP-RA are respectively the brake efficiency of front-wheel and trailing wheel, P _fLand P _fRbe respectively the brake-pressure of front revolver and front right wheel, P _rLand P _rRbe respectively the brake-pressure of rear revolver and rear right wheel.

4. method as claimed in claim 2 or claim 3, wherein, described vehicle weight is all determined in each starting according to the following formula:

$M\left(t\right)=\frac{\mathrm{MMotAct}\left(t\right)\×i_x\left(t\right)}{r\×a_x\left(t\right)}$

Wherein, M (t) is t vehicle weight constantly, a _x(t) be t apparent acceleration/accel constantly, MMotAct (t) is t engine torque constantly, i _x(t) be t change speed gear box transmitting ratio constantly, r is radius of wheel.

5. method as claimed in claim 2, wherein, according to following manner, determine that whether described vehicle is in going up a slope or descent run state:

If the acceleration pedal of described vehicle is not applied to the correction of application force and described apparent acceleration/accel and continues for some time and be less than first threshold, determine that described vehicle is in up-hill journey state;

If correction that the acceleration pedal of described vehicle is not applied to application force and described apparent acceleration/accel detected, continue for some time and be greater than Second Threshold, determine that described vehicle is in descent run state,

Wherein, described first threshold is less than Second Threshold.

6. method as claimed in claim 2, wherein, according to following manner, determine that whether described vehicle is in going up a slope or descent run state:

If the acceleration pedal of described vehicle detected, be applied in application force, the correction that the drive wheel slippage degree of described vehicle is less than the 3rd threshold value and described apparent acceleration/accel continues for some time and is less than first threshold, determines that described vehicle is in up-hill journey state;

If the acceleration pedal of described vehicle detected, be applied in application force, the correction that the drive wheel slippage degree of described vehicle is less than the 3rd threshold value and described apparent acceleration/accel continues for some time and is greater than Second Threshold, determine that described vehicle is in descent run state

Wherein, described first threshold is less than Second Threshold.

7. method as claimed in claim 6, wherein, determine according to the following formula the slippage degree of drive wheel:

$\mathrm{\λ}\left(t\right)=\frac{V\left(t\right)-V_{\mathrm{wheel}}\left(t\right)}{V\left(t\right)}$

Wherein, λ (t) is t slippage degree constantly, and V (t) is t car speed constantly, V _wheel(t) be t drive wheel rotating speed constantly.

8. method as claimed in claim 3, wherein, according to following manner, determine that whether described vehicle is in going up a slope or descent run state:

If the brake pedal of described vehicle detected, be applied in application force, the correction that the drive wheel slippage degree of described vehicle is less than the 3rd threshold value and described apparent acceleration/accel continues for some time and is less than first threshold, determines that described vehicle is in up-hill journey state;

If the brake pedal of described vehicle detected, be applied in application force, the correction that the drive wheel slippage degree of described vehicle is less than the 3rd threshold value and described apparent acceleration/accel continues for some time and is greater than Second Threshold, determine that described vehicle is in descent run state

Wherein, described first threshold is less than Second Threshold.

9. method as claimed in claim 8, wherein, determine according to the following formula the slippage degree of drive wheel:

$\mathrm{\λ}\left(t\right)=\frac{V\left(t\right)-V_{\mathrm{wheel}}\left(t\right)}{V\left(t\right)}$

Wherein, λ (t) is t slippage degree constantly, and V (t) is t car speed constantly, V _wheel(t) be t drive wheel rotating speed constantly.

10. an electronic control unit, comprise input block, output unit and the control unit being coupled with described input block and output unit, wherein, described input block is configured to the detection signal of receiving sensor, described control unit is configured to generate control signal and to actuating unit, export control signal through described output unit according to the kinetic parameter of vehicle, it is characterized in that, described control unit is further configured to the stability of controlling Vehicle Driving Cycle according to following manner:

Utilize described kinetic parameter to revise the apparent acceleration/accel of described vehicle;

According to the correction of described apparent acceleration/accel, determine that whether described vehicle is in ascents and descents motoring condition; And

If described vehicle, in going up a slope or descent run state, improves described vehicle dynamic and controls the sensitivity of intervening.