Ice breaking compensation torque control method and control device

Abstract

The application discloses an EPS ice-breaking compensation torque control method, which comprises the following steps: S1, collecting EPS control data; S2, judging an EPS rack ice blocking and stall condition; S3, calculating an ice-breaking compensation torque according to the EPS rack ice blocking and stall condition; and S4, controlling an EPS motor to output the ice-breaking compensation torque.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of auxiliary driving, and particularly relates to an EPS ice-breaking compensation torque control method and a control device. BACKGROUND

[0002] The current EPS (power-assisted steering system) power-assisted motor transmits torque to the steering rack through gears or a transmission belt. When the rack seal cover collides or ages and causes sealing failure, water vapor is easily accumulated at the gears and the rack or the transmission belt. When the temperature is lower than 0 DEG, ice is formed in the rack, thereby causing the steering rack to be blocked during normal driving. Therefore, the EPS needs to provide ice-breaking compensation torque after detecting the ice blocking condition, so as to realize the normal steering function of the EPS. However, if the torque of the EPS motor is increased for ice removal, the load of the EPS motor is increased if the torque is too large, and meanwhile, the driver is strongly disturbed when the ice breaking is completed; if the torque is too small, the ice cannot be removed normally, and driving risk exists. SUMMARY

[0003] The application aims to solve the technical problem that the current EPS rack cannot provide normal assistance under the condition of ice formation and ensure the safe driving of the driver.

[0004] In order to solve the above technical problem, the application provides an EPS ice-breaking compensation torque control method, which comprises the following steps:

[0005] Step S1, collecting EPS control data, step S2, judging the ice blocking condition of the EPS rack; step S3, calculating the ice-breaking compensation torque according to the ice blocking condition of the EPS rack; and step S4, controlling the EPS motor to output the ice-breaking compensation torque.

[0006] Preferably, the control data comprises temperature, hand torque, motor torque, vehicle speed, steering wheel angle and steering wheel speed.

[0007] Preferably, the control data comprises temperature, hand torque, motor torque, vehicle speed, motor RPS angle and motor RPS speed.

[0008] Preferably, the step S2 judges the ice blocking condition of the EPS rack by setting an ice state flag. The ice state flag is expressed in the following form: 0 represents that the rack is not iced; 1 represents that the rack is iced; and 2 represents that ice breaking is completed and re-icing needs to be prevented.

[0009] Preferably, the method for determining the icing state flag is: when a first preset condition is met, the icing state flag is 0; the first preset condition includes: the temperature is less than a preset temperature threshold, the hand force torque is greater than a preset hand force torque threshold, the motor torque is greater than a preset motor torque threshold, the vehicle speed is greater than a preset vehicle speed threshold, the steering wheel angle is less than a preset steering wheel angle second threshold, and the steering wheel speed is greater than a preset steering wheel speed first threshold.

[0010] Preferably, the method for determining the icing state flag is: when a first preset condition is met, the icing state flag is 0; the first preset condition includes: the temperature is less than a preset temperature threshold, the hand force torque is greater than a preset hand force torque threshold, the motor torque is greater than a preset motor torque threshold, the vehicle speed is greater than a preset vehicle speed threshold, the motor RPS angle is less than a preset motor RPS angle second threshold, and the motor RPS speed is greater than a preset motor RPS speed first threshold.

[0011] Preferably, the method for determining the icing state flag is: when a second preset condition is met, the icing state flag is 1, otherwise it is maintained at 0; the second preset condition is that the duration of the first preset condition is greater than a preset time threshold.

[0012] Preferably, the method for determining the icing state flag is: when a third preset condition is met, the icing state flag is 2; the third preset condition is that the icing state flag is 1, and the steering wheel speed is greater than a preset steering wheel speed second threshold or the motor RPS speed is greater than a motor RPS speed second threshold.

[0013] Preferably, in the step S3, the ice-breaking compensation torque is calculated according to the relationship between the motor torque and the hand force torque.

[0014] Preferably, the ice-breaking compensation torque is a sine wave, a triangular wave, or a square wave.

[0015] Preferably, the method for calculating the ice-breaking compensation torque is: when the icing state flag is 0, the ice-breaking compensation torque is 0 Nm.

[0016] Preferably, the method for calculating the ice-breaking compensation torque is: when the icing state flag is 1, the steering wheel hand force torque is set to a preset first default value; the maximum motor torque amplitude is calculated by interpolation according to the corresponding curve of the motor torque and the hand force torque, the corresponding frequency is calculated by interpolation according to the frequency response of the maximum motor torque amplitude, and the maximum motor torque amplitude and the corresponding frequency constitute the ice-breaking compensation torque.

[0017] Preferably, the ice-breaking compensation torque calculation method is that when the icing state flag bit is 2, the steering wheel hand force torque is set as a preset second default value; the motor torque amplitude maximum value is obtained by interpolation calculation according to the motor torque and the hand force torque corresponding curve; the corresponding frequency is obtained by interpolation calculation according to the frequency response of the motor torque amplitude maximum value, and the motor torque amplitude maximum value and the corresponding frequency constitute the ice-breaking compensation torque.

[0018] The application also provides an EPS ice-breaking compensation torque control device, comprising: a data acquisition module for acquiring EPS control data; an icing state identification module for judging the EPS rack icing stall condition; an ice-breaking torque calculation module for calculating the ice-breaking compensation torque according to the EPS rack icing stall condition and the EPS control data; and an EPS motor for outputting the ice-breaking compensation torque to realize ice breaking.

[0019] Preferably, the data acquisition module comprises a temperature sensor, a vehicle speed sensor, a steering wheel angle and angular velocity sensor, a steering wheel hand force sensor and a motor torque sensor.

[0020] Preferably, the data acquisition module comprises a temperature sensor, a vehicle speed sensor, a motor RPS sensor, a steering wheel hand force sensor and a motor torque sensor. BRIEF DESCRIPTION OF DRAWINGS

[0021] The application will be further described in detail below in combination with the drawings and specific embodiments:

[0022] Figure 1 The figure is a step schematic diagram of the EPS ice-breaking compensation torque control method of embodiment 1.

[0023] Figure 2 The figure is a relationship characteristic diagram of the motor torque and the hand force torque.

[0024] Figure 3 The figure is one of the motor torque interpolation calculation diagrams.

[0025] Figure 4 The figure is another of the motor torque interpolation calculation diagrams.

[0026] Figure 5 The figure is a motor torque frequency response diagram.

[0027] Figure 6 The figure is a structure schematic diagram of the EPS ice-breaking compensation torque control device of embodiment 2. DETAILED DESCRIPTION

[0028] The present application is further illustrated by the following specific embodiments, and other advantages and effects of the present application can be sufficiently understood by those skilled in the art from the disclosure. The present application can also be implemented or applied in different specific embodiments, and the details in the specification can be applied based on different views, with various modifications or changes made without departing from the general design idea of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. The following exemplary embodiments of the present application can be implemented in various forms, and should not be interpreted as being limited to the specific embodiments set forth herein. It should be understood that these embodiments are provided to make the disclosure of the present application complete and complete, and to fully convey the technical solutions of these exemplary embodiments to those skilled in the art.

[0029] Embodiment 1

[0030] As Figure 1 shown, the present embodiment provides an EPS ice breaking compensation torque control method, comprising the following steps:

[0031] Step S1, collecting EPS control data, the control data comprising: temperature T eps , hand torque m tbt , motor torque m mot , vehicle speed v veh , steering wheel angle w str and steering wheel speed v str ; wherein the steering wheel angle and speed can be replaced by motor RPS angle w rps and motor RPS speed v rps ;

[0032] Step S2, judging the ice blocking condition of the EPS rack;

[0033] Step S3, calculating the ice breaking compensation torque according to the ice blocking condition of the EPS rack;

[0034] Step S4, controlling the EPS motor to output the ice breaking compensation torque.

[0035] The ice blocking condition of the EPS rack is judged by setting an ice state flag in step S2. The ice state flag is exemplarily expressed in the following form: 0 represents that the rack is not iced; 1 represents that the rack is iced; 2 represents that the ice breaking is completed and needs to prevent re-icing.

[0036] The determination method of the specific ice state flag is as follows,

[0037] When the first preset condition is met: the temperature is less than the preset temperature threshold (T eps <T min(0°), the hand force torque is greater than a preset hand force torque threshold (m tbt >m min_tbt (0.5 Nm), the motor torque is greater than a preset motor torque threshold (m mot >m min_mot (0.1 Nm), the vehicle speed is greater than a preset vehicle speed threshold (v veh >v min_veh (5 km / h), the steering wheel angle is less than a preset steering wheel angle second threshold (w str <w max_str (450°), and the steering wheel speed is greater than a preset steering wheel speed first threshold (v str >v min_str (0.12° / s).

[0038] or wherein the steering wheel angle and speed are replaced by the motor RPS angle being less than a preset motor RPS angle second threshold (w rps <w max_rps (9450°), and the motor RPS speed being greater than a preset motor RPS speed first threshold (v rps >v min_rps (3° / s), the ice state flag is 0.

[0039] When a second preset condition is met: the duration of the first preset condition is greater than a preset time threshold (e.g., 300 ms), the ice state flag is set to 1, otherwise it is maintained at 0.

[0040] When a third preset condition is met: the ice state flag is 1, and the steering wheel speed is greater than a preset steering wheel speed second threshold (v str >v max_str (0.3° / s) or the motor RPS speed is greater than a motor RPS speed second threshold (v rps_abs >v max_rps (6° / s), the ice state flag is set to 2.

[0041] In step S3, the ice-breaking compensation torque is calculated according to the EPS rack ice blocking stall condition, i.e., the ice state flag, and the relationship between the motor torque and the hand force torque. The ice-breaking compensation torque is a sine wave, a triangular wave, or a square wave.

[0042] An exemplary calculation method is as follows:

[0043] When the ice state flag is 0, the ice-breaking compensation torque is 0 Nm.

[0044] When the icing status flag is 1, to prevent excessive ice-breaking compensation torque from causing steering wheel slippage or loss of steering control, the steering wheel torque is set to the preset first default value (0.6 Nm); the motor torque is calculated based on the interpolation curve of motor torque and steering wheel torque, such as... Figure 2 The motor torque (0.33 Nm) is shown under a steering wheel force of 0.6 Nm; as shown... Figure 3 As shown, the frequency response of the motor at a torque of 0.33 Nm is calculated by interpolation based on the frequency response at motor torques of 0.3 Nm and 0.4 Nm. The frequency corresponding to the maximum value in the frequency response curve at a motor torque of 0.33 Nm is calculated, as shown below. Figure 5 The value shown is 10.62 Hz. Calculate the ice-breaking compensation torque in the form of a sine wave, triangular wave, or square wave with an amplitude of 0.33 Nm and a frequency of 10.62 Hz.

[0045] When the icing status flag is 2, it indicates that ice breaking has been completed, and re-icing during driving should be prevented. To prevent discomfort in steering wheel feel due to compensation torque at this time, the steering wheel torque is set to the second preset default value (0.3Nm); the motor torque is calculated based on the interpolation curve corresponding to the motor torque and the steering wheel torque, such as... Figure 4 The required motor torque for the 0.3 Nm steering wheel force calculation is 0.22 Nm. Based on the frequency characteristics of the motor torques of 0.2 Nm and 0.3 Nm, the frequency characteristics at 0.22 Nm are calculated using interpolation. The frequency corresponding to the maximum value in the frequency characteristic curve at 0.22 Nm is then calculated. Figure 5 The value shown is 11.48 Hz. Calculate the ice-breaking compensation torque in the form of a sine wave, triangular wave, or square wave with an amplitude of 0.22 Nm and a frequency of 11.48 Hz.

[0046] In step S4, the EPS motor is controlled to output ice-breaking compensation torque to perform ice-breaking vibration.

[0047] Example 2

[0048] like Figure 6 As shown, this embodiment provides an EPS ice-breaking compensation torque control device for implementing the control method of Embodiment 1. It includes: a data acquisition module, an icing state identification module, an ice-breaking torque calculation module, and an EPS motor.

[0049] The data acquisition module comprises a temperature sensor, a vehicle speed sensor, a steering wheel angle and angular velocity sensor (or motor RPS sensor), a steering wheel hand force sensor, and a motor torque sensor. The temperature sensor is used to acquire the temperature of the EPS, the vehicle speed sensor is used to acquire the vehicle speed, the steering wheel angle and angular velocity sensor is used to acquire the steering wheel rotation angle and rotation speed, the motor RPS sensor is used to acquire the motor RPS rotation angle and rotation speed, the steering wheel hand force sensor is used to acquire the hand force torque, and the motor torque sensor is used to acquire the motor torque. The icing state identification module is used to determine the icing and blocked rotation condition of the EPS rack. The ice breaking torque calculation module is used to calculate the ice breaking compensation torque according to the icing and blocked rotation condition of the EPS rack and the EPS control data. The EPS motor is used to output the ice breaking compensation torque, thereby achieving ice breaking.

[0050] The application is described in detail above through the specific embodiments and examples, but these do not constitute a limitation on the application. Many modifications and improvements can be made by those skilled in the art without departing from the principles of the application, and these should also be considered as falling within the protection scope of the application.

Claims

1. A method for controlling the ice-breaking compensation torque of EPS, characterized in that, Includes the following steps: Step S1: Collect EPS control data. Step S2: Determine if the EPS rack is stuck due to icing. Step S3: Calculate the ice-breaking compensation torque based on the EPS rack icing and stalling condition; Step S4: Control the EPS motor to output ice-breaking compensation torque; The method for calculating the ice-breaking compensation torque is as follows: when the icing state flag is 1, the steering wheel hand torque is set to a preset first default value; the maximum value of the motor torque amplitude is obtained by interpolation based on the curve corresponding to the motor torque and the hand torque; the corresponding frequency is obtained by interpolation based on the frequency response of the maximum value of the motor torque amplitude; the maximum value of the motor torque amplitude and its corresponding frequency constitute the ice-breaking compensation torque. In step S2, the icing status flag is set to determine the icing and stalling condition of the EPS rack. The icing status flag is represented in the following form: 0 indicates that the rack is not iced; 1 indicates that the rack is iced. 2 indicates that the ice breaking is complete, and it is necessary to prevent re-icing; The method for calculating the ice-breaking compensation torque is as follows: when the icing state flag is 2, the steering wheel hand torque is set to a preset second default value; the maximum value of the motor torque amplitude is obtained by interpolation based on the curve corresponding to the motor torque and the hand torque; the corresponding frequency is obtained by interpolation based on the frequency response of the maximum value of the motor torque amplitude; the maximum value of the motor torque amplitude and its corresponding frequency constitute the ice-breaking compensation torque.

2. The EPS ice-breaking compensation torque control method according to claim 1, characterized in that, The control data includes: temperature, hand torque, motor torque, vehicle speed, steering wheel angle, and steering wheel speed.

3. The EPS ice-breaking compensation torque control method according to claim 1, characterized in that, The control data includes: temperature, hand torque, motor torque, vehicle speed, motor RPS angle, and motor RPS speed.

4. The EPS ice-breaking compensation torque control method according to claim 1, characterized in that, The method for determining the freezing state flag is as follows: When the first preset condition is met, the freezing state flag is set to 0. The first preset conditions include: temperature less than a preset temperature threshold, hand torque greater than a preset hand torque threshold, motor torque greater than a preset motor torque threshold, vehicle speed greater than a preset vehicle speed threshold, steering wheel angle less than a preset steering wheel angle second threshold, and steering wheel speed greater than a preset steering wheel speed first threshold.

5. The EPS ice-breaking compensation torque control method according to claim 1, characterized in that, The method for determining the freezing state flag is as follows: When the first preset condition is met, the freezing state flag will be set to 0; The first preset conditions include: temperature less than a preset temperature threshold, hand torque greater than a preset hand torque threshold, motor torque greater than a preset motor torque threshold, vehicle speed greater than a preset vehicle speed threshold, motor RPS angle less than a preset second threshold for motor RPS angle, and motor RPS speed greater than a preset first threshold for motor RPS speed.

6. The EPS ice-breaking compensation torque control method according to claim 4 or 5, characterized in that, The method for determining the freezing state flag is as follows: When the second preset condition is met, the freezing state flag is set to 1; otherwise, it remains at 0. The second preset condition is that the duration of satisfying the first preset condition is greater than a preset time threshold.

7. The EPS ice-breaking compensation torque control method according to claim 6, characterized in that, The method for determining the freezing state flag is as follows: When the third preset condition is met, the freezing state flag will be set to 2; The third preset condition is that the icing state flag is at position 1, and the steering wheel speed is greater than the preset second threshold of steering wheel speed or the motor RPS speed is greater than the second threshold of motor RPS speed.

8. The EPS ice-breaking compensation torque control method according to claim 1, characterized in that, In step S3, the ice-breaking compensation torque is calculated based on the icing state flag and the relationship between the motor torque and the manual torque.

9. The EPS ice-breaking compensation torque control method according to claim 1, characterized in that, The ice-breaking compensation torque is a sine wave, a triangular wave, or a square wave.

10. The EPS ice-breaking compensation torque control method according to claim 1, characterized in that, The ice-breaking compensation torque is calculated as follows: when the icing state flag is 0, the ice-breaking compensation torque is 0 Nm.

11. An EPS ice-breaking compensation torque control device, using the EPS ice-breaking compensation torque control method as described in any one of claims 1-10, characterized in that, include: The data acquisition module is used to collect EPS control data; The icing condition identification module is used to determine the icing and stall condition of the EPS rack; The ice-breaking torque calculation module is used to calculate the ice-breaking compensation torque based on the EPS rack icing and stall conditions and EPS control data. EPS motors are used to output ice-breaking compensation torque to achieve ice breaking.

12. The EPS ice-breaking compensation torque control device according to claim 11, characterized in that, The data acquisition module includes a temperature sensor, a vehicle speed sensor, a steering wheel angle and angular velocity sensor, a steering wheel hand force sensor, and a motor torque sensor.

13. The EPS ice-breaking compensation torque control device according to claim 11, characterized in that, The data acquisition module includes a temperature sensor, a vehicle speed sensor, a motor RPS sensor, a steering wheel force sensor, and a motor torque sensor.

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