CN113276685A

CN113276685A - Energy recovery control method based on steering wheel turning angle and steering rate

Info

Publication number: CN113276685A
Application number: CN202110454847.7A
Authority: CN
Inventors: 曹姜; 袁雁城; 张飞; 张澄宇; 祖春胜
Original assignee: Anhui Yuchi Intelligent Technology Co ltd
Current assignee: Anhui Yuchi Intelligent Technology Co ltd
Priority date: 2021-04-26
Filing date: 2021-04-26
Publication date: 2021-08-20

Abstract

The invention discloses an energy recovery control method based on steering wheel turning angle and steering speed, and relates to the technical field of new energy automobiles. The invention comprises the following steps: detecting whether the vehicle is in a sliding state or not, or a driver releases an accelerator pedal and depresses a brake pedal; step two: the VCU determines a current allowed energy recovery value T according to the chargeable capacity of the battery and the executable maximum recovery capacity of the motor; step three: the VCU corrects the energy recovery value according to the vehicle speed, and the corrected energy recovery value T1 is T V; step four: VCU based on steering wheel angle alpha, and steering rate V_αAnd performing adaptive correction control on the energy recovery value T1, wherein the energy recovery value after adaptive correction is T2-T1A, and A is more than 0 and less than or equal to 1. According to the invention, the capacity recovery value of the vehicle is corrected according to the steering wheel rotation angle and the steering speed, so that the problems that the stability of the vehicle body is influenced due to overlarge acting force of the conventional energy recovery and the ESC is triggered to cause the energy recovery efficiency are solved.

Description

Energy recovery control method based on steering wheel turning angle and steering rate

Technical Field

The invention belongs to the technical field of new energy automobiles, and particularly relates to an energy recovery control method based on steering wheel turning angles and steering speed.

Background

For a pure electric or hybrid vehicle type, an energy recovery function is necessary to reduce energy consumption and emission and improve the endurance mileage at the same time. Whether the vehicle is coasting or braking energy recovery, relevant boundary conditions should be considered during recovery to limit the amount of recovered kinetic energy to ensure stability and comfort of the vehicle during recovery.

The prior art is an implementation form of the current general energy recovery control, and considers the stability of a vehicle body while considering the capacities of a battery and a motor. But has certain limitations:

firstly, no energy recovery adaptive adjustment control exists in the steering process; according to the principle of friction circle, the acting force of the ground to the wheels is certain, and if the longitudinal force is larger during the steering process, such as the energy recovery acting force, the transverse acting force provided by the ground is smaller, so that the vehicle has larger transverse acceleration and yaw during the steering process, and the stability of the vehicle body is reduced.

Secondly, in the above process, if the vehicle lateral acceleration reaches a certain value, the stability control function of the ESC (vehicle body electronic stability system) is triggered, the VCU (vehicle control unit) generally adopts a strategy of directly exiting energy recovery, and even if the ESC exits control, the ESC cannot enter energy recovery again in the current braking or sliding process, thereby reducing the recovery efficiency.

Disclosure of Invention

The invention aims to provide an energy recovery control method based on a steering wheel angle and a steering rate, which solves the problems that the existing energy recovery acting force is too large, the stability of a vehicle body is influenced, and ESC is triggered to cause energy recovery efficiency by correcting the capacity recovery value of a vehicle according to the steering wheel angle and the steering rate.

In order to solve the technical problems, the invention is realized by the following technical scheme:

the invention relates to an energy recovery control method based on steering wheel turning angle and steering speed, which comprises the following steps:

the method comprises the following steps: detecting whether the vehicle is in a sliding state or not, or a driver releases an accelerator pedal and depresses a brake pedal; if yes, entering the next step; if not, continuing to maintain the detection state;

step two: the VCU determines a current allowed energy recovery value T according to the chargeable capacity of the battery and the executable maximum recovery capacity of the motor;

step three: the VCU corrects an energy recovery value according to the vehicle speed, wherein the corrected energy recovery value is T1, and T1 is T × V; wherein V is more than or equal to 0 and less than or equal to 1;

step four: VCU based on steering wheel angle alpha, and steering rate V_αAnd performing adaptive correction control on the energy recovery value T1, wherein the energy recovery value after adaptive correction is T2, T2 is T1A, A is an initial correction coefficient, and A is more than 0 and less than or equal to 1.

Further, in the second step, if the driver presses the accelerator pedal at this time, the process returns to the first step.

Furthermore, in the fourth step, alpha is more than or equal to 0 degree and less than or equal to 520 degrees, and V is more than or equal to 0 degree_α≤1000。

Further, when alpha is more than or equal to 0 degree and less than or equal to 175 degrees and V is more than or equal to 0 degree_αWhen the value is less than or equal to 340, the value of A is more than or equal to 0.7 and less than or equal to 1; when alpha is more than 175 degrees and less than or equal to 385 degrees and 340 is more than V_αWhen the value is less than or equal to 612, the value of A is more than or equal to 0.4 and less than 0.7; when alpha is more than 385 degrees and less than or equal to 520 degrees and 612 degrees and V_αWhen the value is less than or equal to 1000, the value of A is more than 0 and less than 0.4.

Further, the self-learning correction of the initial correction coefficient A comprises the following steps:

a. when the system enters energy recovery, judging whether the steering wheel angle alpha is larger than 0, whether the lateral acceleration of the vehicle body is larger than a calibrated value Ag or whether the yaw rate of the vehicle body is larger than a calibrated value omega, if so, entering the next step, and if not, exiting the self-learning correction step;

b. determining the steering wheel angle and the steering rate under the current working condition, the current lateral acceleration Ag ', and the current yaw rate omega'; correcting the initial correction coefficient A under the working condition, namely replacing the original initial correction coefficient A under the corresponding working condition by a correction value A'; where L1 ═ g/ag ', L2 ═ ω/ω', correction value a 'takes the minimum value of L1 and L2, i.e., a' ═ min (L1, L2).

Further, the lateral acceleration calibration value Ag is 0.1g, and the yaw rate calibration value omega is 15 deg/s.

Further, in the self-learning correction process, if the ESC triggers the relevant stability control function and the vehicle exceeds three triggers in one ignition cycle or the single trigger time exceeds the calibration value, the current operating point is considered to be unreliable, and the initial correction coefficient a of the operating point is not corrected.

Further, the single trigger time calibration value is 2-10 seconds.

The invention has the following beneficial effects:

according to the invention, the initial correction coefficient is determined according to the steering wheel angle and the steering rate, and the energy recovery value is controlled through the initial correction coefficient, so that the condition that the vehicle has larger transverse acceleration and yaw in the steering process of the vehicle due to overlarge energy recovery acting force, and the stability of the vehicle body is reduced is avoided, and the stability of the vehicle body is effectively improved.

Meanwhile, the situation that the ESC of the vehicle is easily triggered due to overlarge energy recovery in the steering process of the vehicle to cause the vehicle to exit the energy recovery is reduced, and therefore the overall energy recovery efficiency is effectively improved.

The self-adaptive adjustment ensures the energy recovery of the vehicle in the steering process, and improves the recovery efficiency as much as possible on the premise of ensuring the stability.

Of course, it is not necessary for any product in which the invention is practiced to achieve all of the above-described advantages at the same time.

Drawings

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

Fig. 1 is a flowchart of an energy recovery control method based on a steering wheel angle and a steering rate according to the present invention.

FIG. 2 is a table of the angle of rotation and the rate of steering versus the initial correction factor of energy return.

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.

Referring to fig. 1, the present invention is an energy recovery control method based on steering wheel angle and steering speed, comprising the following steps:

the method comprises the following steps: detecting whether the vehicle is in a sliding state or not, or a driver releases an accelerator pedal and depresses a brake pedal; if yes, entering the next step; if not, the detection state is continuously kept.

Step two: the VCU determines a current allowed energy recovery value T according to the chargeable capacity of the battery and the executable maximum recovery capacity of the motor, such as determining the energy recovery value T of the electric automobile according to the real-time speed, the brake signal and the working condition of the electric automobile. And if the driver presses the accelerator pedal at the moment, returning to the step one.

Step three: the VCU corrects an energy recovery value according to the vehicle speed, wherein the corrected energy recovery value is T1, and T1 is T × V; and V is more than or equal to 0 and less than or equal to 1, if the vehicle speed is higher, the value of V is larger, otherwise, the value of V is smaller, and when V is 0, namely the vehicle speed is over-small, the vehicle energy recovery is exited.

Step four: VCU based on steering wheel angle alpha, and steering rate V_αThe energy recovery value T1 is subjected to adaptive correction control, the energy recovery value after adaptive correction is T2, T2 is T1A, wherein A is an initial correction coefficient, A is more than 0 and less than or equal to 1, alpha is more than or equal to 0 and less than or equal to 520 degrees, and V is more than or equal to 0 and less than or equal to 520 degrees_α≤1000，V_αIs a divided by time, i.e. the angle of rotation per unit time, in deg/s.

Meanwhile, as shown in FIG. 2, when α is 0 ° ≦ 175 °, and V is 0 ≦ V_αAnd when the value is not more than 340, the value A is not less than 0.7 and not more than 1, the state of the value A indicates that the vehicle turns less and does not turn sharply any more, the value A is larger, and the energy recovery value is improved under the condition of ensuring the stability of the vehicle.

When alpha is more than 175 degrees and less than or equal to 385 degrees and 340 is more than V_αAnd when the value is less than or equal to 612, the value of A is more than or equal to 0.4 and less than 0.7, which indicates that the vehicle has a large turn, and the energy return value is reduced.

When alpha is more than 385 degrees and less than or equal to 520 degrees and 612 degrees and V_αWhen the value is less than or equal to 1000, the value of A is more than 0 and less than 0.4, which indicates that the vehicle runs through a larger bend angle or is positioned at a sharp turning position, the value of A is reduced, and the energy return value is reduced, so that the stability of the vehicle body caused by the vehicle bending is ensured. In the above process, if the vehicle speed is too low, the vehicle also exits the energy recovery as described in step three.

Preferably, the energy recovery control method based on the steering wheel angle and the steering rate further comprises self-learning correction of the initial correction coefficient A, and comprises the following steps:

a. when the system enters energy recovery, whether the steering wheel angle alpha is larger than 0 and whether the lateral acceleration of the vehicle body is larger than a calibrated value Ag or whether the yaw rate is larger than a calibrated value omega is judged, if yes, the next step is carried out, and if not, the self-learning correction step is exited, wherein the calibrated value of the lateral acceleration Ag is 0.1g, and the calibrated value of the yaw rate omega is 15 deg/s.

b. Determining the steering wheel angle and the steering rate under the current working condition, the current lateral acceleration Ag ', and the current yaw rate omega'; correcting the initial correction coefficient A under the working condition, namely replacing the original initial correction coefficient A under the corresponding working condition by a correction value A';

where L1 ═ g/ag ', L2 ═ ω/ω', correction value a 'takes the minimum value of L1 and L2, i.e., a' ═ min (L1, L2).

For example, when the steering wheel angle alpha is 60 degrees and V is_αWhen the initial correction coefficient is 100 degrees/s, the original initial correction coefficient A is 0.8; when under the same operating conditions, i.e. alpha is 60 DEG, V_αAt 100 deg./s, the current lateral acceleration Ag 'is 0.2g, or the current yaw rate omega' is 25 deg/s.

If L1 is 0.1g/0.2g is 0.5 and L2 is 15/25 is 0.6, the correction value a' is 0.5 and the original initial correction coefficient a under the same operating condition is 0.8, which is replaced with 0.5. And in the power-off process of the vehicle, the VCU writes the corrected A 'value into Flash, and the VCU directly calls the A' value when the vehicle is powered on next time and meets the same working condition. Therefore, the self-learning correction process is realized, the energy recovery of the vehicle under different working conditions is more accurate, and the motion state of the vehicle body is more stable when the energy of the vehicle is recovered under each working condition.

Meanwhile, in the self-learning correction process, if the ESC triggers the relevant stability control function and the vehicle exceeds three times of triggering in one ignition cycle or the single triggering time exceeds the calibration value, the current working condition point is considered to be untrustworthy, and the initial correction coefficient A of the working condition point is not corrected. The calibration value of the single triggering time is 2-10 seconds, if the ESC triggering time reaches 5 seconds, the stability of the vehicle at the moment is poor, if the vehicle slips and the like, the parameter accuracy at the moment is poor, and therefore data acquisition is not carried out under the condition, and the initial correction coefficient A is not corrected.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An energy recovery control method based on a steering wheel angle and a steering rate, characterized by comprising the steps of:

2. The method according to claim 1, wherein in the second step, if the driver depresses the accelerator pedal, the method returns to the first step.

3. The energy recovery control method according to claim 1 or 2 based on the steering wheel angle and the steering rateCharacterized in that in the fourth step, alpha is more than or equal to 0 degree and less than or equal to 520 degrees, and V is more than or equal to 0 degree_α≤1000。

4. The method of claim 3, wherein the steering angle and steering rate are controlled such that α is 0 ° or more and 175 ° or less and V is 0 or more_αWhen the value is less than or equal to 340, the value of A is more than or equal to 0.7 and less than or equal to 1;

when alpha is more than 175 degrees and less than or equal to 385 degrees and 340 is more than V_αWhen the value is less than or equal to 612, the value of A is more than or equal to 0.4 and less than 0.7;

when alpha is more than 385 degrees and less than or equal to 520 degrees and 612 degrees and V_αWhen the value is less than or equal to 1000, the value of A is more than 0 and less than 0.4.

5. The method of claim 4, comprising a self-learning correction to the initial correction factor A, comprising the steps of:

6. The method of claim 5 where the lateral acceleration rating is 0.1g and the yaw rate rating ω is 15 deg/s.

7. The method as claimed in claim 5 or 6, wherein in the self-learning correction process, if the ESC triggers the relevant stability control function and the vehicle exceeds three triggers in one ignition cycle or the single trigger time exceeds the calibration value, the current operating point is considered as being not reliable, and the initial correction coefficient A of the operating point is not corrected.

8. The method of claim 7, wherein the single trigger time calibration is 2-10 seconds.