阅读说明：本技术 一种电动助力转向系统的助力控制方法、装置及汽车 (Power-assisted control method and device of electric power-assisted steering system and automobile ) 是由 张伟 于 2021-06-29 设计创作，主要内容包括：本发明提供了一种电动助力转向系统的助力控制方法、装置及汽车,用于解决车辆在练习停车入库场景下的电机过热问题。该方法包括：基于车辆的车速、驾驶员手力矩、方向盘最大转角和倒挡次数,判断车辆当前是否处于练习停车入库场景；若车辆当前处于练习停车入库场景,则电动助力转向系统的助力特性曲线选择为预设的练车入库曲线；基于车辆的车速和驾驶员手力矩,按照所述练车入库曲线插值得到第一助力电流,所述电动助力转向系统按照所述第一助力电流进行输出；其中,同一车速和驾驶员手力矩条件下,所述练车入库曲线中对应的助力电流小于正常助力曲线中对应的助力电流。(The invention provides a power-assisted control method and device of an electric power-assisted steering system and an automobile, which are used for solving the problem of motor overheating of the automobile in a parking and warehousing practicing scene. The method comprises the following steps: judging whether the vehicle is in a parking practicing and warehousing scene currently or not based on the vehicle speed, the hand torque of a driver, the maximum turning angle of a steering wheel and the reverse gear times of the vehicle; if the vehicle is currently in a practice parking garage-in scene, selecting a power-assisted characteristic curve of the electric power-assisted steering system as a preset practice parking garage-in curve; interpolating according to the driving practice warehousing curve to obtain a first power-assisted current based on the speed of the vehicle and the hand torque of a driver, and outputting by the electric power-assisted steering system according to the first power-assisted current; under the condition of the same vehicle speed and the same hand torque of a driver, the corresponding power-assisted current in the driving practice warehousing curve is smaller than the corresponding power-assisted current in the normal power-assisted curve.)

1. A power assist control method of an electric power steering system, characterized by comprising:

judging whether the vehicle is in a parking practicing and warehousing scene currently or not based on the vehicle speed, the hand torque of a driver, the maximum turning angle of a steering wheel and the reverse gear times of the vehicle;

if the vehicle is currently in a practice parking garage-in scene, selecting a power-assisted characteristic curve of the electric power-assisted steering system as a preset practice parking garage-in curve;

interpolating according to the driving practice warehousing curve to obtain a first power-assisted current based on the speed of the vehicle and the hand torque of a driver, and outputting by the electric power-assisted steering system according to the first power-assisted current;

under the condition of the same vehicle speed and the same hand torque of a driver, the corresponding power-assisted current in the driving practice warehousing curve is smaller than the corresponding power-assisted current in the normal power-assisted curve.

2. The method of claim 1, wherein the step of determining whether the vehicle is currently in a parking garage practice scenario comprises:

if the vehicle speed is less than a first preset vehicle speed, the driver hand torque is greater than the first preset torque, the accumulated time length exceeds a preset time length, the number of times that the steering wheel corner is the maximum corner is greater than or equal to a first preset number of times, and the number of times of reverse gear is greater than or equal to a second preset number of times within a first preset time period, determining that the vehicle is parked once and put in storage;

if the vehicle is continuously parked and warehoused for N times, determining that the vehicle is currently in a parking practice warehousing scene;

the second preset time interval consists of a plurality of first preset time intervals.

3. The method of claim 1, wherein if the vehicle is currently in a practice parking garage scenario, the method further comprises:

and starting a terminal protection function by the electric power steering system, so that the first power current output by the electric power steering system according to the driving practice warehousing curve is multiplied by the power gain smaller than or equal to 1 by the electric power steering system to obtain the power current finally output by the electric power steering system.

4. A method according to claim 3, wherein the power assist gain is determined by steering wheel angle, wherein the greater the steering wheel angle, the smaller the corresponding power assist gain.

5. The method according to claim 1, characterized in that in the preset driving garage entry curve, the temperature of the vehicle motor is lower than the maximum allowable motor working temperature in a preset continuous time period by the aid of the power-assisted current corresponding to each vehicle speed and the hand torque of the driver.

6. The method of claim 3, further comprising:

judging whether the vehicle exits a parking practice and warehousing scene or not based on the vehicle speed, the driver hand moment and the steering wheel rotating angular speed of the vehicle;

if the vehicle exits the parking and warehousing practice scene, the electric power steering system closes the tail end protection function, and the power characteristic curve of the electric power steering system is selected as a preset normal power curve.

7. The method of claim 6, wherein the step of determining whether the vehicle exits the parking garage entry scenario comprises:

and if the vehicle speed is greater than a second preset vehicle speed, the driver hand moment is less than a second preset moment and the steering wheel rotating angular speed is less than a preset rotating angular speed within a second preset time period, determining that the vehicle exits from a practice parking and warehousing scene.

8. A power assist control device of an electric power steering system, characterized by comprising:

the first judgment module is used for judging whether the vehicle is in a parking practicing and warehousing scene or not at present based on the vehicle speed, the hand torque of a driver, the maximum turning angle of a steering wheel and the reverse gear times of the vehicle;

the first selection module is used for selecting the power-assisted characteristic curve of the electric power-assisted steering system as a preset driving practice warehousing curve if the vehicle is currently in a driving practice warehousing scene;

the first control module is used for interpolating according to the driving practice warehousing curve to obtain a first power-assisted current based on the speed of a vehicle and the hand torque of a driver, and the electric power-assisted steering system outputs the first power-assisted current;

under the condition of the same vehicle speed and the same hand torque of a driver, the corresponding power-assisted current in the driving practice warehousing curve is smaller than the corresponding power-assisted current in the normal power-assisted curve.

9. An automobile characterized by comprising the assist control device of the electric power steering system according to claim 8.

Technical Field

The invention relates to the field of automobile electronic control systems, in particular to a power-assisted control method and device of an electric power-assisted steering system and an automobile.

Background

In recent years, the technology of the automobile industry is rapidly developed, and the technology in the field of automobile electronic control is more and more popular. The requirement of people on the steering performance of automobiles is also increasing day by day. In order to ensure that the vehicle has ideal operation stability when the steering wheel is rotated under any working condition, the steering wheel can be easily and freely rotated even if the vehicle is stopped; at present, more and more middle and low-end vehicle types gradually realize the carrying of an Electric Power Steering (EPS) system and basically realize the standard matching; the EPS is a power-assisted steering system that directly relies on an electric motor to provide assist torque. The system only needs to control the direction and the amplitude of the current of the motor, and does not need complicated mechanical and hydraulic mechanisms.

Because the electric power steering system provides the auxiliary torque by the electric motor, the system will overheat if the working time is too long, and enter a thermal protection mode, so that the system does not work, thereby having the following defects:

the driving school or the new driver has shorter time for practicing parking and warehousing; if the driving practice time is increased, the motor capacity needs to be enlarged;

the cost increases. If the thermal protection performance needs to be improved, the capacity of the motor needs to be enlarged, so that the cost is increased;

after the capacity of the motor is enlarged, the volume and the weight are increased, which is not beneficial to the arrangement of parts of the whole vehicle and the weight of the whole vehicle is increased;

for a steering system, the capacity of a motor is enlarged, a new system is developed similarly, the period is long, and the time node of the whole vehicle cannot be met.

Disclosure of Invention

The invention provides a power-assisted control method and device of an electric power-assisted steering system and an automobile, which are used for solving the problem of motor overheating of the automobile in a parking and warehousing practicing scene.

The technical scheme of the invention is as follows:

the invention provides a power-assisted control method of an electric power-assisted steering system, which comprises the following steps: judging whether the vehicle is in a parking practicing and warehousing scene currently or not based on the vehicle speed, the hand torque of a driver, the maximum turning angle of a steering wheel and the reverse gear times of the vehicle;

if the vehicle is currently in a practice parking garage-in scene, selecting a power-assisted characteristic curve of the electric power-assisted steering system as a preset practice parking garage-in curve;

interpolating according to the driving practice warehousing curve to obtain a first power-assisted current based on the speed of the vehicle and the hand torque of a driver, and outputting by the electric power-assisted steering system according to the first power-assisted current;

under the condition of the same vehicle speed and the same hand torque of a driver, the corresponding power-assisted current in the driving practice warehousing curve is smaller than the corresponding power-assisted current in the normal power-assisted curve.

Preferably, the step of judging whether the vehicle is currently in the scene of practicing parking and warehousing comprises the following steps:

if the vehicle speed is less than a first preset vehicle speed, the driver hand torque is greater than the first preset torque, the accumulated time length exceeds a preset time length, the number of times that the steering wheel corner is the maximum corner is greater than or equal to a first preset number of times, and the number of times of reverse gear is greater than or equal to a second preset number of times within a first preset time period, determining that the vehicle is parked once and put in storage;

if the vehicle is continuously parked and warehoused for N times, determining that the vehicle is currently in a parking practice warehousing scene;

the second preset time interval consists of a plurality of first preset time intervals.

Preferably, if the vehicle is currently in a parking garage practice scene, the method further comprises:

and starting a terminal protection function by the electric power steering system, so that the first power current output by the electric power steering system according to the driving practice warehousing curve is multiplied by the power gain smaller than or equal to 1 by the electric power steering system to obtain the power current finally output by the electric power steering system.

Preferably, the power assist gain is determined by a steering wheel angle, wherein the larger the steering wheel angle, the smaller the corresponding power assist gain.

Preferably, in a preset driving practice warehousing curve, the temperature of a vehicle motor in a preset continuous time period is lower than the maximum allowable working temperature of the motor by the aid of power-assisted currents corresponding to each vehicle speed and the hand torque of a driver.

Preferably, the method further comprises:

judging whether the vehicle exits a parking practice and warehousing scene or not based on the vehicle speed, the driver hand moment and the steering wheel rotating angular speed of the vehicle;

if the vehicle exits the parking and warehousing practice scene, the electric power steering system closes the tail end protection function, and the power characteristic curve of the electric power steering system is selected as a preset normal power curve.

Preferably, the step of judging whether the vehicle exits the parking garage entering practice scene comprises:

and if the vehicle speed is greater than a second preset vehicle speed, the driver hand moment is less than a second preset moment and the steering wheel rotating angular speed is less than a preset rotating angular speed within a second preset time period, determining that the vehicle exits from a practice parking and warehousing scene.

The present invention also provides a power assist control device of an electric power steering system, including:

the first judgment module is used for judging whether the vehicle is in a parking practicing and warehousing scene or not at present based on the vehicle speed, the hand torque of a driver, the maximum turning angle of a steering wheel and the reverse gear times of the vehicle;

the first selection module is used for selecting the power-assisted characteristic curve of the electric power-assisted steering system as a preset driving practice warehousing curve if the vehicle is currently in a driving practice warehousing scene;

the first solving module is used for interpolating according to the driving practice warehousing curve to obtain a first power-assisted current based on the speed of a vehicle and the hand torque of a driver, and the electric power-assisted steering system outputs the first power-assisted current;

under the condition of the same vehicle speed and the same hand torque of a driver, the corresponding power-assisted current in the driving practice warehousing curve is smaller than the corresponding power-assisted current in the normal power-assisted curve.

Preferably, if the vehicle is currently in a parking garage practice scene, the apparatus further includes:

and the second solving module is used for controlling the electric power steering system to start a terminal protection function, so that the electric power steering system multiplies the first power current output according to the driving entering curve by a gain value smaller than 1 to obtain the power current finally output by the electric power steering system.

Preferably, the apparatus further comprises:

the second judgment module is used for judging whether the vehicle exits a parking training and warehousing scene or not based on the vehicle speed, the driver hand moment and the steering wheel rotation deceleration of the vehicle;

the second selection module is used for closing the tail end protection function of the electric power steering system if the vehicle exits the scene of practicing parking and warehousing, and the power-assisted characteristic curve of the electric power steering system is selected as a preset normal power-assisted curve;

and the third solving module is used for interpolating according to the normal power-assisted curve to obtain a second power-assisted current based on the vehicle speed and the hand torque of the driver, and the electric power-assisted steering system outputs the second power-assisted current.

The invention also provides an automobile comprising the power-assisted control device of the electric power-assisted steering system.

The invention has the beneficial effects that:

under the premise of not enlarging the motor capacity (namely not increasing the cost), the time for driving schools or new drivers to practice parking and warehousing is prolonged. The electric power steering system can identify the working condition that a driver is in a driving garage or uses large current, adjust the power characteristic curve of the electric power steering system after identification and start a terminal protection function, so that the power current output by the electric power steering system is reduced, the thermal protection performance of the electric power steering system is improved, and the service time of the electric power steering system is prolonged; also, this technique does not change the motor or the reduction mechanism used in the electric power steering system.

Drawings

FIG. 1 is a schematic flow diagram of the process of the present invention;

FIG. 2 is a schematic view of an identification process of a vehicle entering a driving practice warehousing scene;

FIG. 3 is a schematic view of a recognition process of a scene in which a driver has quitted driving and enters a garage;

FIG. 4 is a schematic diagram of a boost current solution;

FIG. 5 is a comparison graph of a normal boosting curve and a driving practice warehousing curve.

Detailed Description

The invention is further described with reference to the accompanying drawings in which:

referring to fig. 1, an embodiment of the present invention provides a power control method for an electric power steering system, where the method can be used to practice parking garage adaptive identification, and the method of the embodiment includes the following steps:

firstly, electrifying the whole vehicle;

secondly, the electric power steering system completes initialization;

thirdly, identifying the warehousing exercise function; when recognizing that the driver is practicing parking and warehousing, performing the fourth step;

fourthly, the electric power steering system starts a tail end protection function and switches the power characteristic curve of the electric power steering system into a 'driving and garage entering' mode;

fifthly, judging whether the warehousing exercise is finished or not in real time by the electric power steering system, if the warehousing exercise is not finished, judging all the time, and if the warehousing exercise is finished, performing a sixth step;

sixthly, the electric power steering system closes the tail end protection function and the power-assisted characteristic curve is switched back to a normal power-assisted curve;

and seventhly, returning to the third step after relevant parameters in the calculation and identification processes are cleared.

In a preset driving practice warehousing curve, the temperature of a vehicle motor in a preset continuous time period is lower than the maximum allowable working temperature of the motor by the aid of power-assisted currents corresponding to each vehicle speed and the hand torque of a driver.

Referring to fig. 2, in the embodiment of the present invention, the process of performing real-time recognition practice for parking into a garage includes the following conditions and steps:

step one, starting timing after entering a warehousing exercise identification module;

and secondly, identifying and judging whether the driver parks or not, wherein the identification conditions simultaneously meet the following five conditions:

(1) the vehicle speed is less than a preset vehicle speed value (< 15kph, calibratable). (the vehicle speed source is the vehicle speed signal received on the CAN bus);

(2) the hand moment of the driver is larger than the preset moment value, and the accumulated time exceeds a certain preset time length (2.5 Nm, which can be calibrated; and the accumulated time is more than 10s, which can be calibrated). (the hand moment of the driver is the hand moment of the steering wheel, and is specifically derived from the moment of the steering wheel operated by the driver measured by a torque sensor of the electric power steering system);

(3) the number of times of the direction corner, which is the maximum corner (MaxAngle), is more than or equal to a first preset number (MaxAngle =500 degrees, can be calibrated, and the number of times is more than or equal to 3, and can be calibrated). (the source of the steering wheel angle is the angle of the steering wheel operated by the driver measured by the steering angle sensor of the electric power steering system);

(4) the reverse gear frequency is greater than or equal to a second preset frequency (greater than or equal to 2, and can be calibrated). (the reverse gear signal is from the transmission gear signal received on the CAN bus);

(5) and if the four conditions are met within the first preset time period, determining that one parking and warehousing (the time is less than 210s, and the calibration can be carried out).

Thirdly, recognizing that one-time parking is carried out for warehousing after the five conditions are met, and adding 1 to the warehousing frequency ParkingNum;

and fourthly, judging whether the warehousing times ParkingNum is a certain threshold (3, can be calibrated). When the threshold value is reached, recognizing that the vehicle is in a parking practice warehousing scene; if the threshold value is not reached, the fifth step is carried out;

fifthly, resetting the timer, entering the next cycle and returning to the first step;

referring to fig. 3, in the embodiment of the present invention, the identifying that the vehicle is in the parking garage training scenario further includes the following conditions and steps:

firstly, timing is started after a power-assisted characteristic curve of an electric power-assisted steering system is switched to a driving and warehousing curve;

and secondly, identifying and judging whether the driver finishes parking practice and warehousing (namely judging whether the vehicle exits a parking practice and warehousing scene), wherein the identification conditions simultaneously meet the following four conditions:

(1) the vehicle speed is greater than a second preset vehicle speed (> 25kph, which can be calibrated). (vehicle speed: vehicle speed signal received on CAN bus)

(2) The driver hand torque is less than a second preset torque (<1.2Nm, calibratable). (steering wheel hand moment: the magnitude of the moment of the driver's steering wheel measured by the electric power steering system torque sensor)

(3) The steering wheel rotational angular velocity is less than the preset rotational angular velocity (< 0.5rev/s, calibratable). (angular velocity: steering wheel rotational angular velocity measured by an electric power steering system steering angle sensor)

(4) The above three conditions are satisfied for a second predetermined period (> 10s, calibratable).

Step three, after the four conditions are simultaneously met, recognizing that the practice of parking and warehousing is finished (namely the vehicle exits the practice of parking and warehousing scene);

fourthly, resetting the timer, entering the next cycle, and returning to the first step;

referring to fig. 4, in the embodiment of the present invention, a specific process of turning on a terminal protection function of an electric power steering system includes the following steps:

firstly, inquiring a training warehousing curve by using a vehicle Speed (V _ Speed) and a Hand torque (Hand _ Tq) to obtain a power-assisted current (I);

a second step of inquiring a boosting Gain (Gain) by a steering wheel Angle (Steer _ Angle), the boosting Gain being less than or equal to 1, and the boosting Gain being gradually decreased as the Angle increases near the tip end;

multiplying the boosting current (I) by a boosting Gain (Gain) to obtain the boosting current which is finally output as the electric power steering system;

and fourthly, the boosting current output by the electric power steering system is reduced relative to the boosting current output by the vehicle under the same condition in a normal driving scene, so that the heating value is reduced, and the thermal protection performance is better.

Referring to fig. 5, the boost characteristic curve of the present invention has the following characteristics:

firstly, when the electric power steering system is used for normal power assistance, a power assistance characteristic curve participating in calculation of power assistance current is a normal power assistance curve;

secondly, when the driver is recognized to be practicing, the power-assisted current participating in calculating the power-assisted current is switched into a driving practice warehousing curve;

and thirdly, comparing the two groups of curves, wherein the power-assisted current of the driving practice warehousing curve is smaller than that of the normal power-assisted curve, namely the power-assisted current corresponding to the driving practice warehousing curve is small under the condition of the same vehicle speed and the same hand moment, so that the heat productivity can be reduced, and the heat protection performance can be improved.

The present invention also provides a power assist control device of an electric power steering system, including:

the first judgment module is used for judging whether the vehicle is in a parking practicing and warehousing scene or not at present based on the vehicle speed, the hand torque of a driver, the maximum turning angle of a steering wheel and the reverse gear times of the vehicle;

the first selection module is used for selecting the power-assisted characteristic curve of the electric power-assisted steering system as a preset driving practice warehousing curve if the vehicle is currently in a driving practice warehousing scene;

the first solving module is used for interpolating according to the driving practice warehousing curve to obtain a first power-assisted current based on the speed of a vehicle and the hand torque of a driver, and the electric power-assisted steering system outputs the first power-assisted current;

under the condition of the same vehicle speed and the same hand torque of a driver, the corresponding power-assisted current in the driving practice warehousing curve is smaller than the corresponding power-assisted current in the normal power-assisted curve.

Preferably, if the vehicle is currently in a parking garage practice scene, the apparatus further includes:

and the second solving module is used for controlling the electric power steering system to start a terminal protection function, so that the electric power steering system multiplies the first power current output according to the driving entering curve by a gain value smaller than 1 to obtain the power current finally output by the electric power steering system.

Preferably, the apparatus further comprises:

the second judgment module is used for judging whether the vehicle exits a parking training and warehousing scene or not based on the vehicle speed, the driver hand moment and the steering wheel rotation deceleration of the vehicle;

the second selection module is used for closing the tail end protection function of the electric power steering system if the vehicle exits the scene of practicing parking and warehousing, and the power-assisted characteristic curve of the electric power steering system is selected as a preset normal power-assisted curve;

and the third solving module is used for interpolating according to the normal power-assisted curve to obtain a second power-assisted current based on the vehicle speed and the hand torque of the driver, and the electric power-assisted steering system outputs the second power-assisted current.

The invention also provides an automobile comprising the power-assisted control device of the electric power-assisted steering system.