CN110406591B - Vehicle active alignment method and system - Google Patents

Abstract

The invention discloses a vehicle active alignment method and a system, wherein the method comprises the following steps: the method comprises the steps of obtaining vehicle load, vehicle front tire pressure, vehicle speed and steering wheel parameters, determining target self-adaptive parameters based on the vehicle load and the vehicle front tire pressure, and determining whether to control the vehicle to enter an active return-to-positive state or not by judging whether corresponding variables in the steering wheel parameters and the target self-adaptive parameters meet preset conditions or not when the vehicle is determined to be in the inactive return-to-positive state, so that the vehicle is subjected to return-to-positive torque control after the vehicle enters the active return-to-positive state. Because the target adaptive parameter is related to the vehicle load and the tire pressure of the front wheel of the vehicle, the invention realizes the adaptive active aligning control of the vehicle based on the vehicle load and the tire pressure of the front wheel of the vehicle, and avoids the problem that the aligning performance of the same vehicle is inconsistent under different use working conditions, thereby improving the driving safety and the driving experience of the vehicle.

Description

Vehicle active alignment method and system

Technical Field

The invention relates to the technical field of automobile electronics, in particular to a vehicle active alignment method and system.

Background

In the existing vehicle active aligning method, a controller generally calculates to obtain an active aligning torque by using steering wheel torque, steering wheel rotation angle and vehicle speed, and then the controller outputs a corresponding active aligning torque to a power-assisted motor to realize active aligning of the vehicle.

As the aligning moment characteristics of each vehicle type are different, a set of corresponding algorithm parameters is configured for each vehicle type in the calibration stage. However, the tire pressure and the vehicle load of the same vehicle can change greatly during the use process, and the tire pressure and the vehicle load can significantly affect the aligning torque characteristic of the vehicle, so that the aligning performance is changed. If the aligning torque characteristic calibration is carried out by taking a lighter vehicle load or a higher tire pressure as a standard, the aligning torque characteristic calibration can cause the situation of too violent aligning in the use of vehicles with heavier vehicle loads or lower tire pressures, so that the vehicle instability is caused, and the driving safety is seriously influenced. If the calibration is carried out by taking the heavier vehicle load or the lower tire pressure as the standard, the situation of correction insufficiency can occur in the use of the lighter vehicle load or the vehicle with the higher tire pressure, so that the experience of a driver is reduced.

Therefore, how to provide a vehicle active alignment method to achieve adaptive adjustment of vehicle active alignment becomes a technical problem that needs to be solved urgently by those skilled in the art.

Disclosure of Invention

In view of the above, the invention discloses a vehicle active aligning method and system, so as to realize vehicle adaptive active aligning control based on vehicle load and vehicle front tire pressure, and avoid the problem that aligning performance of the same vehicle is inconsistent under different use conditions, thereby improving driving safety and driving experience of the vehicle.

A method of active vehicle alignment, comprising:

obtaining vehicle load, vehicle front tire pressure, vehicle speed and steering wheel parameters, wherein the steering wheel parameters comprise: steering wheel angle, rate of change of steering wheel angle, steering wheel torque, rate of change of steering wheel torque, and time window;

determining target adaptive parameters of the acquired vehicle load and the acquired vehicle front tire pressure from a pre-stored corresponding relation between the vehicle load and the adaptive parameters and a corresponding relation between the vehicle front tire pressure and the adaptive parameters, wherein the adaptive parameters comprise: a steering wheel change rate threshold value of the steering wheel in the positive direction, a steering wheel change rate threshold value of the steering wheel in the negative direction, a steering wheel torque threshold value, an entering time window duration threshold value, an exiting time window duration threshold value, a moment proportional controller control parameter which is actively rightly output, and a vehicle speed coefficient which is actively rightly controlled;

judging whether the vehicle is in an inactive return state or not;

when the vehicle is in the non-active return-to-positive state, determining whether the vehicle enters an active return-to-positive state or not based on a turning angle change rate threshold value of the steering wheel in the positive direction, a turning angle change rate threshold value of the steering wheel in the negative direction, a steering wheel torque threshold value, an entering time window duration threshold value and the steering wheel parameters;

and when the vehicle is determined to enter the active aligning state, obtaining an active aligning torque based on the control parameter of the active aligning output torque proportional controller, the active aligning control vehicle speed coefficient, the steering wheel torque, the steering wheel angle and the vehicle speed, and performing aligning torque control on the vehicle by using the active aligning torque.

Optionally, when the vehicle is in the inactive return-to-positive state, based on the threshold of the rate of change of the steering wheel in the positive direction, the threshold of the rate of change of the steering wheel in the negative direction, the threshold of the steering wheel torque, the threshold of the time window duration of entry, and the steering wheel parameter, it is determined whether the vehicle enters the active return-to-positive state, specifically including:

judging whether the vehicle is in the non-active return-to-positive state or the active return-to-positive state at present;

when the vehicle is determined to be in the non-active return-to-positive state currently, judging whether the absolute value of the steering wheel torque is smaller than the absolute value of the steering wheel torque threshold value or not, and whether the product of the steering wheel torque change rate and the steering wheel rotation angle is smaller than zero or not;

if yes, judging whether a first condition or a second condition is satisfied, wherein the first condition is as follows: the steering wheel corner is greater than zero and the steering wheel corner change rate is less than the steering wheel corner change rate threshold in the positive direction, the second condition is: the steering wheel angle is smaller than zero, and the steering wheel angle change rate is larger than the steering wheel angle change rate threshold value in the opposite direction;

if so, judging whether the time window duration is greater than the time window duration threshold;

and if so, controlling the vehicle to enter the active return state.

Optionally, the method further includes:

when the vehicle is determined to be in the active return-to-positive state currently, judging whether the absolute value of the steering wheel torque is larger than the absolute value of the steering wheel torque threshold value or not, and whether the product of the steering wheel torque change rate and the steering wheel rotation angle is larger than zero or not;

if so, judging whether the time window duration is greater than the exit time window duration threshold value;

and if so, controlling the vehicle to exit the active return state.

Optionally, the determining the obtained target adaptive parameter of the vehicle load and the vehicle front tire pressure from the pre-stored corresponding relationship between the vehicle load and the adaptive parameter and the corresponding relationship between the vehicle front tire pressure and the adaptive parameter specifically includes:

searching the obtained adaptive parameter corresponding to the vehicle load from the corresponding relation between the vehicle load and the adaptive parameter, and recording the adaptive parameter as a first adaptive parameter;

searching the obtained adaptive parameter corresponding to the pressure of the front tire of the vehicle from the corresponding relation between the pressure of the front tire of the vehicle and the adaptive parameter, and recording the adaptive parameter as a second adaptive parameter;

and calculating the average value of the same parameter in the first adaptive parameter and the second adaptive parameter to obtain the target adaptive parameter.

A vehicle active return system comprising:

the acquisition unit is used for acquiring vehicle load, vehicle front tire pressure, vehicle speed and steering wheel parameters, and the steering wheel parameters comprise: steering wheel angle, rate of change of steering wheel angle, steering wheel torque, rate of change of steering wheel torque, and time window;

a first determining unit, configured to determine a target adaptive parameter of an acquired vehicle load and a target adaptive parameter of a vehicle front tire pressure from a pre-stored correspondence relationship between the vehicle load and the adaptive parameter and a correspondence relationship between the vehicle front tire pressure and the adaptive parameter, where the adaptive parameter includes: a steering wheel change rate threshold value of the steering wheel in the positive direction, a steering wheel change rate threshold value of the steering wheel in the negative direction, a steering wheel torque threshold value, an entering time window duration threshold value, an exiting time window duration threshold value, a moment proportional controller control parameter which is actively rightly output, and a vehicle speed coefficient which is actively rightly controlled;

the judging unit is used for judging whether the vehicle is in an inactive return state or not;

a second determination unit, configured to determine whether the vehicle enters an active return-to-positive state based on the threshold of the rate of change of the steering wheel in the positive direction, the threshold of the rate of change of the steering wheel in the negative direction, the threshold of the steering wheel torque, the threshold of the time window duration of entry, and the steering wheel parameter, if the determination unit determines yes;

and the aligning control unit is used for obtaining an active aligning moment based on the control parameter of the active aligning output moment proportional controller, the active aligning control vehicle speed coefficient, the steering wheel torque, the steering wheel angle and the vehicle speed when the vehicle is determined to enter the active aligning state, and performing aligning moment control on the vehicle by using the active aligning moment.

Optionally, the second determining unit specifically includes:

the first judgment subunit is used for judging whether the vehicle is currently in the non-active return-to-positive state or the active return-to-positive state;

a second judgment subunit, configured to, when the first judgment unit determines that the vehicle is currently in the inactive return-to-positive state, judge whether an absolute value of the steering wheel torque is smaller than an absolute value of the steering wheel torque threshold, and whether a product of the steering wheel torque change rate and the steering wheel angle is smaller than zero;

a third determining subunit, configured to determine whether a first condition or a second condition is satisfied if the second determining subunit determines that the first condition is satisfied, where the first condition is: the steering wheel corner is greater than zero and the steering wheel corner change rate is less than the steering wheel corner change rate threshold in the positive direction, the second condition is: the steering wheel angle is smaller than zero, and the steering wheel angle change rate is larger than the steering wheel angle change rate threshold value in the opposite direction;

a fourth judging subunit, configured to, if the third judging subunit judges that the time window duration is greater than the entry time window duration threshold, judge whether the time window duration is greater than the entry time window duration threshold;

and the first control subunit is used for controlling the vehicle to enter the active return state under the condition that the fourth judgment subunit judges that the vehicle is in the active return state.

Optionally, the second determining unit further includes:

a fifth judging subunit, configured to, when the first judging unit determines that the vehicle is currently in the active return-to-positive state, judge whether an absolute value of the steering wheel torque is greater than an absolute value of the steering wheel torque threshold, and whether a product of the steering wheel torque change rate and the steering wheel angle is greater than zero;

a sixth judging subunit, configured to, if the fifth judging subunit judges that the time window duration is greater than the exit time window duration threshold, judge whether the time window duration is greater than the exit time window duration threshold;

and the second control subunit is used for controlling the vehicle to exit the active returning state under the condition that the sixth judgment subunit judges that the vehicle is in the active returning state.

Optionally, the first determining unit specifically includes:

the first searching subunit is used for searching the acquired adaptive parameter corresponding to the vehicle load from the corresponding relation between the vehicle load and the adaptive parameter and recording the adaptive parameter as a first adaptive parameter;

the second searching subunit is used for searching the adaptive parameter corresponding to the acquired front tire pressure of the vehicle from the corresponding relation between the front tire pressure of the vehicle and the adaptive parameter, and recording the adaptive parameter as a second adaptive parameter;

and the calculating subunit is configured to calculate an average value of the same parameter in the first adaptive parameter and the second adaptive parameter, so as to obtain the target adaptive parameter.

From the technical scheme, the invention discloses a vehicle active correction method and a system, wherein the method comprises the following steps: the method comprises the steps of obtaining vehicle load, vehicle front tire pressure, vehicle speed and steering wheel parameters, determining target self-adaptive parameters based on the vehicle load and the vehicle front tire pressure, and determining whether to control the vehicle to enter an active return-to-positive state or not by judging whether corresponding variables in the steering wheel parameters and the target self-adaptive parameters meet preset conditions or not when the vehicle is determined to be in the inactive return-to-positive state, so that the vehicle is subjected to return-to-positive torque control after the vehicle enters the active return-to-positive state. Because the target adaptive parameter is related to the vehicle load and the tire pressure of the front wheel of the vehicle, the invention realizes the adaptive active aligning control of the vehicle based on the vehicle load and the tire pressure of the front wheel of the vehicle, and avoids the problem that the aligning performance of the same vehicle is inconsistent under different use working conditions, thereby improving the driving safety and the driving experience of the vehicle.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the disclosed drawings without creative efforts.

FIG. 1 is a flow chart of an active vehicle alignment method according to an embodiment of the present invention;

FIG. 2 is a flowchart of a self-adaptive active return control method according to an embodiment of the present invention;

FIG. 3 is a flowchart illustrating the aligning torque control after the vehicle enters the active aligning state according to the embodiment of the present invention;

FIG. 4 is a flowchart of a self-adaptive exit active return control method according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of an active vehicle centering system according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the invention discloses a vehicle active alignment method and a system, wherein the method comprises the following steps: the method comprises the steps of obtaining vehicle load, vehicle front tire pressure, vehicle speed and steering wheel parameters, determining target self-adaptive parameters based on the vehicle load and the vehicle front tire pressure, and determining whether to control the vehicle to enter an active return-to-positive state or not by judging whether corresponding variables in the steering wheel parameters and the target self-adaptive parameters meet preset conditions or not when the vehicle is determined to be in the inactive return-to-positive state, so that the vehicle is subjected to return-to-positive torque control after the vehicle enters the active return-to-positive state. Because the target adaptive parameter is related to the vehicle load and the tire pressure of the front wheel of the vehicle, the invention realizes the adaptive active aligning control of the vehicle based on the vehicle load and the tire pressure of the front wheel of the vehicle, and avoids the problem that the aligning performance of the same vehicle is inconsistent under different use working conditions, thereby improving the driving safety and the driving experience of the vehicle.

Referring to fig. 1, a flowchart of a vehicle active-return method according to an embodiment of the present invention is disclosed, and the method includes the steps of:

s101, acquiring vehicle load, vehicle front tire pressure, vehicle speed and steering wheel parameters;

specifically, in practical application, the left front tire pressure of the vehicle and the right front tire pressure of the vehicle can be respectively obtained, and the average value of the left front tire pressure and the right front tire pressure is calculated to obtain the vehicle front tire pressure.

Wherein the steering wheel parameters include: steering wheel angle, rate of change of steering wheel angle, steering wheel torque, rate of change of steering wheel torque, and time window. The specific acquisition process of the steering wheel parameters can be referred to the existing mature scheme, and is not described herein again.

Step S102, determining target adaptive parameters of the acquired vehicle load and the vehicle front tire pressure from a pre-stored corresponding relationship between the vehicle load and the adaptive parameters and a corresponding relationship between the vehicle front tire pressure and the adaptive parameters;

wherein the adaptive parameters include: d theta₁、dθ₂、T(θ)、dt₁、dt₂、K_parAnd K_var，dθ₁Threshold value of rate of change of steering angle of steering wheel in positive direction, d theta₂Is a steering angle change rate threshold value of the steering wheel in the reverse direction, T (theta) is a steering wheel torque threshold value, dt₁To enter a time window duration threshold, dt₂For the exit time window duration threshold, K_parOutputting moment proportional controller control parameters for active correction, K_varThe vehicle speed coefficient is controlled for active return-to-positive.

The acquisition process of the corresponding relation between the vehicle load and the adaptive parameters comprises the following steps: under different vehicle loads, if d θ₁、dθ₂If T (theta) is too large, the active return-to-positive cannot be performed, and at this time, d theta is reduced₁、dθ₂T (theta); on the contrary, if d θ₁、dθ₂If T (theta) is too small, it is easy to cause error entering into active return-to-positive state, and at this time, d theta is increased₁、dθ₂T (theta); if dt₁、dt₂Too large, it will be prolongedActively returning to positive, at which point dt is reduced₁、dt₂If dt is₁、dt₂If it is too small, the vehicle will be shaken, and dt is increased₁、dt₂. If K is_par、K_varIf the size is too large, the device will actively return to the positive and violent overshoot, and at this moment, the device will turn down K_par、K_varIf K is_par、K_varWhen the angle is too small, the return-to-normal residual angle is large, and K is increased_par、K_var。

The acquisition process of the corresponding relation between the tire pressure of the front wheel of the vehicle and the self-adaptive parameters comprises the following steps: under different vehicle front tire presses, if d θ₁、dθ₂If T (theta) is too large, the active return-to-positive cannot be performed, and at this time, d theta is reduced₁、dθ₂T (theta); on the contrary, if d θ₁、dθ₂If T (theta) is too small, it is easy to cause error entering into active return-to-positive state, and at this time, d theta is increased₁、dθ₂T (theta); if dt₁、dt₂If too large, the active return-to-positive will be prolonged, and dt is reduced₁、dt₂If dt is₁、dt₂If it is too small, the vehicle will be shaken, and dt is increased₁、dt₂. If K is_par、K_varIf the size is too large, the device will actively return to the positive and violent overshoot, and at this moment, the device will turn down K_par、K_varIf K is_par、K_varWhen the angle is too small, the return-to-normal residual angle is large, and K is increased_par、K_var。

It should be noted that each variable in the adaptive parameter is obtained by performing on-line debugging through a real vehicle test. These parameters not only affect the entry time and exit time of the active return-to-positive state, but also affect the duration of the coupling of the active return-to-positive control and the basic assist control. And, each variable in the adaptive parameter is related to the vehicle load and the vehicle front tire pressure.

When the vehicle is heavily loaded, the front axle load of the vehicle is reduced, and the vehicle aligning speed is increased. When the front tire pressure of the vehicle is low, the friction between the tire and the ground is increased, and the return speed is reduced. Correspondingly, when the aligning speed is increased, the values of all variables in the adaptive parameters need to be increased; when the return speed decreases, the values of the respective variables in the adaptive parameters need to be decreased.

Step S102 specifically includes:

searching the adaptive parameter corresponding to the acquired vehicle load from the corresponding relation between the vehicle load and the adaptive parameter, and recording the adaptive parameter as a first adaptive parameter;

searching the adaptive parameter corresponding to the obtained front tire pressure of the vehicle from the corresponding relation between the front tire pressure of the vehicle and the adaptive parameter, and recording the adaptive parameter as a second adaptive parameter;

and calculating the average value of the same parameters in the first adaptive parameter and the second adaptive parameter to obtain the target adaptive parameter.

Step S103, judging whether the vehicle is in an inactive return-to-positive state, if so, executing step S104;

it is assumed that the variable AR _ State represents the active return State, the variable AR _ State has only two values 0 and 1, where 1 represents that the vehicle is in the active return State, 0 represents that the vehicle is in the inactive return State, and the initial value of AR _ State is 0.

Therefore, in practical applications, it may be determined whether the vehicle is in the inactive return state based on the value of the variable characterizing the active return state.

Step S104, determining whether the vehicle enters an active return-to-positive state or not based on a steering wheel change rate threshold value in the positive direction, a steering wheel change rate threshold value in the negative direction, a steering wheel torque threshold value, an entering time window duration threshold value and a steering wheel parameter, and if so, executing step S105;

specifically, referring to fig. 2, a flowchart of a self-adaptive active return control method disclosed in an embodiment of the present invention includes:

step S201, judging whether the vehicle is in a non-active return-to-positive state or an active return-to-positive state at present;

that is, step S201 determines whether the active return State variable AR _ State is 0 or 1, and when the vehicle is in the inactive return State, AR _ State is 0; when the vehicle is in the active return State, AR _ State is 1.

Step S202, when the vehicle is determined to be in the non-active return-to-positive state at present, judging whether the absolute value of the steering wheel torque is smaller than the absolute value of a steering wheel torque threshold value or not, and whether the product of the steering wheel torque change rate and the steering wheel rotation angle is smaller than zero or not, if so, executing step S203, and if not, returning to execute step S201;

suppose that the steering wheel angle theta, the steering wheel angle change rate delta theta, and the steering wheel torque T_sThe rate of change of steering wheel torque is deltaT_sTime window delta _ T and steering wheel torque threshold T (θ). Wherein the steering wheel torque is T_sRefers to the torque output by a torque sensor on the vehicle, and the change rate of the steering wheel torque is deltaT_sRefers to the rate of change of torque output by the torque sensor.

Specifically, when the active return state control of the vehicle is performed, it is first necessary to determine the return state of the vehicle at present. When it is determined that the vehicle is in the inactive return-to-normal State, that is, when AR _ State is 0, it is determined that | T_s|<| T (θ) | and deltaT_s*θ<If 0 is true, if so, the process continues to step S203.

Step S203, judging whether the first condition or the second condition is satisfied, if so, executing step S204, and if not, returning to step S201;

wherein the first condition is: the steering wheel angle is greater than zero and the rate of change of the steering wheel angle is less than a threshold rate of change of the steering wheel angle in the positive direction, i.e., theta > 0 and delta theta < d theta₁。

The second condition is: the steering wheel angle is less than zero and the rate of change of the steering wheel angle is greater than a threshold rate of change of the steering wheel angle in the opposite direction, i.e., theta < 0 and delta theta > d theta₂。

And step S204, judging whether the time window duration is greater than the time window duration threshold, if so, executing step S205, and if not, returning to step S201.

That is, step S204 is delta _ t > dt₁。

Step S205, the vehicle is controlled to enter the active return State, that is, the active return State variable AR _ State is 1.

It should be noted that, when one of the determination conditions in this embodiment is not satisfied, the process returns to step S201 to continuously determine whether the vehicle is currently in the inactive return-to-positive state or the active return-to-positive state, and at this time, the vehicle is still in the basic assistance state or the passive return-to-positive state.

In summary, when the vehicle is determined to be in the inactive return-to-positive state, whether the vehicle is controlled to enter the active return-to-positive state is determined by judging whether the steering wheel torque, the steering wheel torque change rate, the steering wheel angle change rate and the corresponding variable in the time window and the target adaptive parameter meet the preset conditions, so that the return-to-positive torque control is performed on the vehicle after the vehicle enters the active return-to-positive state. Because the target adaptive parameter is related to the vehicle load and the tire pressure of the front wheel of the vehicle, the invention realizes the adaptive active aligning control of the vehicle based on the vehicle load and the tire pressure of the front wheel of the vehicle, and avoids the problem that the aligning performance of the same vehicle is inconsistent under different use working conditions, thereby improving the driving safety and the driving experience of the vehicle.

Step S105, outputting a moment proportional controller control parameter K based on active aligning_parAnd actively returning to positive to control the speed coefficient K_varSteering wheel torque T_sAnd the steering wheel rotation angle theta and the vehicle speed to obtain an active aligning torque, and performing aligning torque control on the vehicle by using the active aligning torque.

Specifically, referring to fig. 3, a flowchart of a aligning torque control after the vehicle enters the active aligning mode according to an embodiment of the present invention is shown, in fig. 3, aim ω is a target rotation speed, act ω is an actual rotation speed, K is_parOutputting moment proportional controller control parameters for active correction, K_varFor active return-to-positive control of the vehicle speed coefficient, F(s) is a low pass filter transfer function; g (S) is a transfer function of the active return output to the steering wheel speed, T_arThe final output active aligning moment of the motor.

The target rotation speed aim ω in fig. 3 is obtained from an active return module of a conventional active return system, which can be specifically referred toThe existing schemes are not described in detail herein. Shown in fig. 3 is the tracking feedback control of the target rotation speed aim ω. Subtracting the actual rotating speed act omega from the target rotating speed aim omega to obtain a control error, and multiplying the control error by a control parameter K of the active correcting output torque proportional controller in turn_parActively returning to positive control speed coefficient K_varThe transfer function F(s) of the low-pass filter is used for obtaining the final output active aligning moment T of the motor_arActive return torque T_arAnd multiplying the target active aligning moment by a transfer function G (S) of the active aligning output to the rotating speed of the steering wheel, and applying the target active aligning moment to a mechanical system to generate an actual rotating speed act omega.

In summary, the vehicle active aligning method disclosed by the invention obtains the vehicle load, the vehicle front tire pressure, the vehicle speed and the steering wheel parameter, determines the target adaptive parameter based on the vehicle load and the vehicle front tire pressure, and determines whether to control the vehicle to enter the active aligning state or not by judging whether the corresponding variable in the steering wheel parameter and the target adaptive parameter meets the preset condition or not when determining that the vehicle is in the inactive aligning state, so that the aligning moment control is performed on the vehicle after the vehicle enters the active aligning state. Because the target adaptive parameter is related to the vehicle load and the tire pressure of the front wheel of the vehicle, the invention realizes the adaptive active aligning control of the vehicle based on the vehicle load and the tire pressure of the front wheel of the vehicle, and avoids the problem that the aligning performance of the same vehicle is inconsistent under different use working conditions, thereby improving the driving safety and the driving experience of the vehicle.

In the above embodiment, when the vehicle is in the active returning state, that is, when the determination in step S103 is no, it is determined when the vehicle exits the active returning state.

Therefore, to further optimize the above embodiment, referring to fig. 4, another embodiment of the present invention discloses a flow chart of a method for adaptive exit active return control, the method includes the steps of:

s301, judging whether the vehicle is in a non-active return-to-positive state or an active return-to-positive state at present;

that is, step S301 determines whether the active return State variable AR _ State is 0 or 1.

Step S302, when the vehicle is determined to be in the active return-to-positive state currently, judging whether the absolute value of the steering wheel torque is larger than the absolute value of a steering wheel torque threshold value or not, and whether the product of the steering wheel torque change rate and the steering wheel rotation angle is larger than zero or not, if so, executing step S303, and if not, returning to execute step S301;

specifically, when the vehicle is in the active return State, that is, when AR _ State is equal to 1, it is determined that | T is present_sI > | T (θ) | and deltaT_sIf θ > 0, if yes, go on to step S303.

Step S303, judging whether the time window duration is greater than the exit time window duration threshold, if so, executing step S304, and if not, returning to step S301;

that is, step S303 is such that delta _ t > dt₂。

And step S304, controlling the vehicle to exit the active returning state.

In summary, when the vehicle is determined to be in the active return-to-positive state currently, whether the vehicle is controlled to exit the active return-to-positive state is determined by judging whether the steering wheel torque, the steering wheel torque change rate and the corresponding variables in the time window and the target adaptive parameters meet preset conditions. Because the target adaptive parameter is related to the vehicle load and the tire pressure of the front wheel of the vehicle, the invention realizes the adaptive active aligning control of the vehicle based on the vehicle load and the tire pressure of the front wheel of the vehicle, and avoids the problem that the aligning performance of the same vehicle is inconsistent under different use working conditions, thereby improving the driving safety and the driving experience of the vehicle.

Corresponding to the embodiment of the method, the invention also discloses a vehicle active aligning system.

Referring to fig. 5, a schematic structural diagram of a vehicle active returning system according to an embodiment of the present invention is disclosed, and the system includes: an acquisition unit 401, a first determination unit 402, a judgment unit 403, a second determination unit 404, and a leveling control unit 405.

Wherein, obtain unit 401 for obtain vehicle load, vehicle front tyre pressure, speed of a motor vehicle and steering wheel parameter, the steering wheel parameter includes: steering wheel angle, rate of change of steering wheel angle, steering wheel torque, rate of change of steering wheel torque, and time window;

specifically, in practical application, the left front tire pressure of the vehicle and the right front tire pressure of the vehicle can be respectively obtained, and the average value of the left front tire pressure and the right front tire pressure is calculated to obtain the vehicle front tire pressure.

A first determining unit 402, configured to determine target adaptive parameters of the acquired vehicle load and the vehicle front tire pressure from a pre-stored correspondence between the vehicle load and the adaptive parameter and a correspondence between the vehicle front tire pressure and the adaptive parameter;

wherein the adaptive parameters include: d theta₁、dθ₂、T(θ)、dt₁、dt₂、K_parAnd K_var，dθ₁Threshold value of rate of change of steering angle of steering wheel in positive direction, d theta₂Is a steering angle change rate threshold value of the steering wheel in the reverse direction, T (theta) is a steering wheel torque threshold value, dt₁To enter a time window duration threshold, dt₂For the exit time window duration threshold, K_parOutputting moment proportional controller control parameters for active correction, K_varThe vehicle speed coefficient is controlled for active return-to-positive.

The acquisition process of the corresponding relation between the vehicle load and the adaptive parameters comprises the following steps: under different vehicle loads, if d θ₁、dθ₂If T (theta) is too large, the active return-to-positive cannot be performed, and at this time, d theta is reduced₁、dθ₂T (theta); on the contrary, if d θ₁、dθ₂If T (theta) is too small, it is easy to cause error entering into active return-to-positive state, and at this time, d theta is increased₁、dθ₂T (theta); if dt₁、dt₂If too large, the active return-to-positive will be prolonged, and dt is reduced₁、dt₂If dt is₁、dt₂If it is too small, the vehicle will be shaken, and dt is increased₁、dt₂. If K is_par、K_varIf the size is too large, the device will actively return to the positive and violent overshoot, and at this moment, the device will turn down K_par、K_varIf K is_par、K_varToo small, thenThe return to the positive residual angle is large, and at the moment, K is increased_par、K_var。

The acquisition process of the corresponding relation between the tire pressure of the front wheel of the vehicle and the self-adaptive parameters comprises the following steps: under different vehicle front tire presses, if d θ₁、dθ₂If T (theta) is too large, the active return-to-positive cannot be performed, and at this time, d theta is reduced₁、dθ₂T (theta); on the contrary, if d θ₁、dθ₂If T (theta) is too small, it is easy to cause error entering into active return-to-positive state, and at this time, d theta is increased₁、dθ₂T (theta); if dt₁、dt₂If too large, the active return-to-positive will be prolonged, and dt is reduced₁、dt₂If dt is₁、dt₂If it is too small, the vehicle will be shaken, and dt is increased₁、dt₂. If K is_par、K_varIf the size is too large, the device will actively return to the positive and violent overshoot, and at this moment, the device will turn down K_par、K_varIf K is_par、K_varWhen the angle is too small, the return-to-normal residual angle is large, and K is increased_par、K_var。

It should be noted that each variable in the adaptive parameter is obtained by performing on-line debugging through a real vehicle test. These parameters not only affect the entry time and exit time of the active return-to-positive state, but also affect the duration of the coupling of the active return-to-positive control and the basic assist control. And, each variable in the adaptive parameter is related to the vehicle load and the vehicle front tire pressure.

When the vehicle is heavily loaded, the front axle load of the vehicle is reduced, and the vehicle aligning speed is increased. When the front tire pressure of the vehicle is low, the friction between the tire and the ground is increased, and the return speed is reduced. Correspondingly, when the aligning speed is increased, the values of all variables in the adaptive parameters need to be increased; when the return speed decreases, the values of the respective variables in the adaptive parameters need to be decreased.

The first determining unit 402 may specifically include:

the first searching subunit is used for searching the adaptive parameters corresponding to the acquired vehicle load from the corresponding relationship between the vehicle load and the adaptive parameters, and recording the adaptive parameters as the first adaptive parameters;

the second searching subunit is used for searching the adaptive parameter corresponding to the acquired front tire pressure of the vehicle from the corresponding relation between the front tire pressure of the vehicle and the adaptive parameter, and recording the adaptive parameter as a second adaptive parameter;

and the calculating subunit is used for calculating the average value of the same parameter in the first adaptive parameter and the second adaptive parameter to obtain the target adaptive parameter.

A determination unit 403, configured to determine whether the vehicle is in an inactive return state;

it is assumed that the variable AR _ State represents the active return State, the variable AR _ State has only two values 0 and 1, where 1 represents that the vehicle is in the active return State, 0 represents that the vehicle is in the inactive return State, and the initial value of AR _ State is 0.

Therefore, in practical applications, it may be determined whether the vehicle is in the inactive return state based on the value of the variable characterizing the active return state.

A second determination unit 404, configured to determine whether the vehicle enters the active return-to-positive state based on the threshold of the rate of change of the steering wheel in the positive direction, the threshold of the rate of change of the steering wheel in the negative direction, the threshold of the steering wheel torque, the threshold of the time window duration of entry, and the steering wheel parameter, if the determination unit 403 determines yes;

the second determining unit 404 may specifically include:

the first judgment subunit is used for judging whether the vehicle is in a non-active return-to-positive state or an active return-to-positive state at present;

that is, it is determined whether the active return State variable AR _ State is 0 or 1.

The second judgment subunit is used for judging whether the absolute value of the steering wheel torque is smaller than the absolute value of the steering wheel torque threshold value or not and whether the product of the steering wheel torque change rate and the steering wheel rotation angle is smaller than zero or not when the first judgment unit determines that the vehicle is in the non-active return-to-positive state currently;

suppose that the steering wheel angle theta, the steering wheel angle change rate delta theta, and the steering wheel torque T_sSquare, squareDelta T rate of change of torque to disc_sTime windows delta _ T and T (θ) are steering wheel torque thresholds. Wherein the steering wheel torque is T_sRefers to the torque output by a torque sensor on the vehicle, and the change rate of the steering wheel torque is deltaT_sRefers to the rate of change of torque output by the torque sensor.

Specifically, when the active return state control of the vehicle is performed, it is first necessary to determine the return state of the vehicle at present. When it is determined that the vehicle is in the inactive return-to-normal State, that is, when AR _ State is 0, it is determined that | T_s|<| T (θ) | and deltaT_s*θ<And if the result is 0, continuing to execute the third judgment subunit.

A third determining subunit, configured to determine whether the first condition or the second condition is satisfied if the second determining subunit determines that the first condition is satisfied, where the first condition is: the steering wheel angle is greater than zero and the rate of change of the steering wheel angle is less than a threshold rate of change of the steering wheel angle in the positive direction, i.e., theta > 0 and delta theta < d theta₁. The second condition is: the steering wheel angle is less than zero and the rate of change of the steering wheel angle is greater than a threshold rate of change of the steering wheel angle in the opposite direction, i.e., theta < 0 and delta theta > d theta₂。

The fourth judging subunit is used for judging whether the time window duration is greater than the time window duration threshold value or not under the condition that the third judging subunit judges that the time window duration is greater than the time window duration threshold value;

that is, the fourth judgment subunit is delta _ t > dt₁。

And the first control subunit is used for controlling the vehicle to enter the active return state under the condition that the fourth judgment subunit judges that the vehicle is in the active return state.

In summary, when the vehicle is determined to be in the inactive return-to-positive state, whether the vehicle is controlled to enter the active return-to-positive state is determined by judging whether the steering wheel torque, the steering wheel torque change rate, the steering wheel angle change rate and the corresponding variable in the time window and the target adaptive parameter meet the preset conditions, so that the return-to-positive torque control is performed on the vehicle after the vehicle enters the active return-to-positive state. Because the target adaptive parameter is related to the vehicle load and the tire pressure of the front wheel of the vehicle, the invention realizes the adaptive active aligning control of the vehicle based on the vehicle load and the tire pressure of the front wheel of the vehicle, and avoids the problem that the aligning performance of the same vehicle is inconsistent under different use working conditions, thereby improving the driving safety and the driving experience of the vehicle.

And the aligning control unit 405 is configured to, when it is determined that the vehicle enters the active aligning state, obtain an active aligning torque based on the active aligning output torque proportional controller control parameter, the active aligning control vehicle speed coefficient, the steering wheel torque, the steering wheel rotation angle, and the vehicle speed, and perform aligning torque control on the vehicle by using the active aligning torque.

Specifically, referring to fig. 3, a flowchart of a aligning torque control after the vehicle enters the active aligning mode according to an embodiment of the present invention is shown, in fig. 3, aim ω is a target rotation speed, act ω is an actual rotation speed, K is_parOutputting moment proportional controller control parameters for active correction, K_varFor active return-to-positive control of the vehicle speed coefficient, F(s) is a low pass filter transfer function; g (S) is a transfer function of the active return output to the steering wheel speed, T_arThe final output active aligning moment of the motor.

The target rotation speed aim ω in fig. 3 is obtained by an active return module of a conventional active return system, which may be referred to in the prior art specifically and is not described herein again. Shown in fig. 3 is the tracking feedback control of the target rotation speed aim ω. Subtracting the actual rotating speed act omega from the target rotating speed aim omega to obtain a control error, and multiplying the control error by a control parameter K of the active correcting output torque proportional controller in turn_parActively returning to positive control speed coefficient K_varThe transfer function F(s) of the low-pass filter is used for obtaining the final output active aligning moment T of the motor_arActive return torque T_arAnd multiplying the target active aligning moment by a transfer function G (S) of the active aligning output to the rotating speed of the steering wheel, and applying the target active aligning moment to a mechanical system to generate an actual rotating speed act omega.

In summary, the vehicle active return system disclosed by the invention obtains the vehicle load, the vehicle front tire pressure, the vehicle speed and the steering wheel parameter, determines the target adaptive parameter based on the vehicle load and the vehicle front tire pressure, and determines whether to control the vehicle to enter the active return state or not by judging whether the corresponding variable in the steering wheel parameter and the target adaptive parameter meets the preset condition or not when the vehicle is determined to be in the inactive return state, so that the vehicle is subjected to return moment control after the vehicle enters the active return state. Because the target adaptive parameter is related to the vehicle load and the tire pressure of the front wheel of the vehicle, the invention realizes the adaptive active aligning control of the vehicle based on the vehicle load and the tire pressure of the front wheel of the vehicle, and avoids the problem that the aligning performance of the same vehicle is inconsistent under different use working conditions, thereby improving the driving safety and the driving experience of the vehicle.

In the above embodiments, when the vehicle is in the active return state, it is determined when the vehicle exits the active return state.

Therefore, to further optimize the above embodiment, the second determining unit 404 may specifically include:

a fifth judging subunit, configured to, when the first judging unit determines that the vehicle is currently in the active return-to-positive state, judge whether an absolute value of the steering wheel torque is greater than an absolute value of a steering wheel torque threshold, and whether a product of a steering wheel torque change rate and a steering wheel angle is greater than zero;

specifically, when the vehicle is in the active return State, that is, when the active return State variable AR _ State is equal to 1, it is determined that | T is_sI > | T (θ) | and deltaT_sWhether or not θ > 0 is true.

The sixth judging subunit is configured to, if the fifth judging subunit judges that the time window duration is greater than the exit time window duration threshold, judge whether the time window duration is greater than the exit time window duration threshold;

that is, the sixth judgment unit judges that delta _ t > dt₂Whether or not this is true.

And the second control subunit is used for controlling the vehicle to exit the active returning state under the condition that the sixth judgment subunit judges that the vehicle is in the positive state.

In summary, when the vehicle is determined to be in the active return-to-positive state currently, whether the vehicle is controlled to exit the active return-to-positive state is determined by judging whether the steering wheel torque, the steering wheel torque change rate and the corresponding variables in the time window and the target adaptive parameters meet preset conditions. Because the target adaptive parameter is related to the vehicle load and the tire pressure of the front wheel of the vehicle, the invention realizes the adaptive active aligning control of the vehicle based on the vehicle load and the tire pressure of the front wheel of the vehicle, and avoids the problem that the aligning performance of the same vehicle is inconsistent under different use working conditions, thereby improving the driving safety and the driving experience of the vehicle.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (8)

1. A method of active vehicle alignment, comprising:

obtaining vehicle load, vehicle front tire pressure, vehicle speed and steering wheel parameters, wherein the steering wheel parameters comprise: steering wheel angle, rate of change of steering wheel angle, steering wheel torque, rate of change of steering wheel torque, and time window;

determining target adaptive parameters of the acquired vehicle load and the acquired vehicle front tire pressure from a pre-stored corresponding relation between the vehicle load and the adaptive parameters and a corresponding relation between the vehicle front tire pressure and the adaptive parameters, wherein the adaptive parameters comprise: a steering wheel change rate threshold value of the steering wheel in the positive direction, a steering wheel change rate threshold value of the steering wheel in the negative direction, a steering wheel torque threshold value, an entering time window duration threshold value, an exiting time window duration threshold value, a moment proportional controller control parameter which is actively rightly output, and a vehicle speed coefficient which is actively rightly controlled;

judging whether the vehicle is in an inactive return state or not;

when the vehicle is in the non-active return-to-positive state, determining whether the vehicle enters an active return-to-positive state or not based on a turning angle change rate threshold value of the steering wheel in the positive direction, a turning angle change rate threshold value of the steering wheel in the negative direction, a steering wheel torque threshold value, an entering time window duration threshold value and the steering wheel parameters;

and when the vehicle is determined to enter the active aligning state, obtaining an active aligning torque based on the control parameter of the active aligning output torque proportional controller, the active aligning control vehicle speed coefficient, the steering wheel torque, the steering wheel angle and the vehicle speed, and performing aligning torque control on the vehicle by using the active aligning torque.

2. The method of active vehicle return according to claim 1, wherein determining whether the vehicle enters the active return state based on the steering wheel rate of change threshold in the forward direction, the steering wheel rate of change threshold in the reverse direction, the steering wheel torque threshold, the time window duration of entry threshold, and the steering wheel parameters when the vehicle is in the inactive return state comprises:

judging whether the vehicle is in the non-active return-to-positive state or the active return-to-positive state at present;

when the vehicle is determined to be in the non-active return-to-positive state currently, judging whether the absolute value of the steering wheel torque is smaller than the absolute value of the steering wheel torque threshold value or not, and whether the product of the steering wheel torque change rate and the steering wheel rotation angle is smaller than zero or not;

if yes, judging whether a first condition or a second condition is satisfied, wherein the first condition is as follows: the steering wheel corner is greater than zero and the steering wheel corner change rate is less than the steering wheel corner change rate threshold in the positive direction, the second condition is: the steering wheel angle is smaller than zero, and the steering wheel angle change rate is larger than the steering wheel angle change rate threshold value in the opposite direction;

if so, judging whether the time window duration is greater than the time window duration threshold;

and if so, controlling the vehicle to enter the active return state.

3. The method of active vehicle return to claim 2, further comprising:

when the vehicle is determined to be in the active return-to-positive state currently, judging whether the absolute value of the steering wheel torque is larger than the absolute value of the steering wheel torque threshold value or not, and whether the product of the steering wheel torque change rate and the steering wheel rotation angle is larger than zero or not;

if so, judging whether the time window duration is greater than the exit time window duration threshold value;

and if so, controlling the vehicle to exit the active return state.

4. The vehicle active return method according to claim 1, wherein the determining the obtained target adaptive parameters of the vehicle load and the vehicle front tire pressure from a pre-stored correspondence relationship between the vehicle load and the adaptive parameters and a correspondence relationship between the vehicle front tire pressure and the adaptive parameters specifically comprises:

searching the obtained adaptive parameter corresponding to the vehicle load from the corresponding relation between the vehicle load and the adaptive parameter, and recording the adaptive parameter as a first adaptive parameter;

searching the obtained adaptive parameter corresponding to the pressure of the front tire of the vehicle from the corresponding relation between the pressure of the front tire of the vehicle and the adaptive parameter, and recording the adaptive parameter as a second adaptive parameter;

and calculating the average value of the same parameter in the first adaptive parameter and the second adaptive parameter to obtain the target adaptive parameter.

5. A vehicle active return system, comprising:

the acquisition unit is used for acquiring vehicle load, vehicle front tire pressure, vehicle speed and steering wheel parameters, and the steering wheel parameters comprise: steering wheel angle, rate of change of steering wheel angle, steering wheel torque, rate of change of steering wheel torque, and time window;

a first determining unit, configured to determine a target adaptive parameter of an acquired vehicle load and a target adaptive parameter of a vehicle front tire pressure from a pre-stored correspondence relationship between the vehicle load and the adaptive parameter and a correspondence relationship between the vehicle front tire pressure and the adaptive parameter, where the adaptive parameter includes: a steering wheel change rate threshold value of the steering wheel in the positive direction, a steering wheel change rate threshold value of the steering wheel in the negative direction, a steering wheel torque threshold value, an entering time window duration threshold value, an exiting time window duration threshold value, a moment proportional controller control parameter which is actively rightly output, and a vehicle speed coefficient which is actively rightly controlled;

the judging unit is used for judging whether the vehicle is in an inactive return state or not;

a second determination unit, configured to determine whether the vehicle enters an active return-to-positive state based on the threshold of the rate of change of the steering wheel in the positive direction, the threshold of the rate of change of the steering wheel in the negative direction, the threshold of the steering wheel torque, the threshold of the time window duration of entry, and the steering wheel parameter, if the determination unit determines yes;

and the aligning control unit is used for obtaining an active aligning moment based on the control parameter of the active aligning output moment proportional controller, the active aligning control vehicle speed coefficient, the steering wheel torque, the steering wheel angle and the vehicle speed when the vehicle is determined to enter the active aligning state, and performing aligning moment control on the vehicle by using the active aligning moment.

6. The active vehicle return system of claim 5, wherein the second determination unit specifically comprises:

the first judgment subunit is used for judging whether the vehicle is currently in the non-active return-to-positive state or the active return-to-positive state;

a second judgment subunit, configured to, when the first judgment subunit determines that the vehicle is currently in the inactive return-to-positive state, judge whether an absolute value of the steering wheel torque is smaller than an absolute value of the steering wheel torque threshold, and whether a product of the steering wheel torque change rate and the steering wheel angle is smaller than zero;

a third determining subunit, configured to determine whether a first condition or a second condition is satisfied if the second determining subunit determines that the first condition is satisfied, where the first condition is: the steering wheel corner is greater than zero and the steering wheel corner change rate is less than the steering wheel corner change rate threshold in the positive direction, the second condition is: the steering wheel angle is smaller than zero, and the steering wheel angle change rate is larger than the steering wheel angle change rate threshold value in the opposite direction;

a fourth judging subunit, configured to, if the third judging subunit judges that the time window duration is greater than the entry time window duration threshold, judge whether the time window duration is greater than the entry time window duration threshold;

and the first control subunit is used for controlling the vehicle to enter the active return state under the condition that the fourth judgment subunit judges that the vehicle is in the active return state.

7. The vehicle active return-to-positive system of claim 6, wherein the second determination unit further comprises:

a fifth judging subunit, configured to, when the first judging subunit determines that the vehicle is currently in the active return-to-positive state, judge whether an absolute value of the steering wheel torque is greater than an absolute value of the steering wheel torque threshold, and whether a product of the steering wheel torque change rate and the steering wheel angle is greater than zero;

a sixth judging subunit, configured to, if the fifth judging subunit judges that the time window duration is greater than the exit time window duration threshold, judge whether the time window duration is greater than the exit time window duration threshold;

and the second control subunit is used for controlling the vehicle to exit the active returning state under the condition that the sixth judgment subunit judges that the vehicle is in the active returning state.

8. The active vehicle return system of claim 5, wherein the first determining unit specifically comprises:

the first searching subunit is used for searching the acquired adaptive parameter corresponding to the vehicle load from the corresponding relation between the vehicle load and the adaptive parameter and recording the adaptive parameter as a first adaptive parameter;

the second searching subunit is used for searching the adaptive parameter corresponding to the acquired front tire pressure of the vehicle from the corresponding relation between the front tire pressure of the vehicle and the adaptive parameter, and recording the adaptive parameter as a second adaptive parameter;

and the calculating subunit is configured to calculate an average value of the same parameter in the first adaptive parameter and the second adaptive parameter, so as to obtain the target adaptive parameter.

Images