Steering pinion angle finding and correction system

Abstract

The present invention relates to a system (1) for detecting, verifying and correcting the pinion angle (PA) deviation of the electric power steering system of a vehicle.

Description

[0001] DESCRIPTION

[0002] STEERING PINION ANGLE FINDING AND CORRECTION SYSTEM

[0003] Technical Field

[0004] The present invention relates to a system for detecting, verifying and correcting the pinion angle (PA) deviation of the electric power steering system of a vehicle.

[0005] Background of the Invention

[0006] The steering angle of a vehicle with a rack and pinion type steering system is determined by the pinion angle. This pinion angle is measured by the angle sensor mounted on the electric power steering (EPS) motor. In cases where the EPS motor angle sensor is a relative sensor, the angle value is initialized by another sensor, called the steering angle sensor (SAS), which is mounted on the steering and measures the absolute angle of the steering. In general, this initialization is performed when the ignition of the vehicle starts. The EPS engine angle sensor records the SAS angle at ignition start and then uses the respective angle sensor to measure the pinion angle.

[0007] The pinion angle is used indirectly by the driver by directing the steering wheel and directly by various driver assistance systems such as lane centering, lane changing, automatic parking, as well as emergency functions such as emergency lane keeping and evasive maneuvering. Any angular error between the steering wheel angle (SWA) and the pinion angle (PA) that is present when the pinion angle is initialized may result in reduced performance of the driver assistance systems. For an EPS system with a Pinion Angle Controller (PAC), there is an interface such that the drive support system sends a PA command and the PAC aims to follow this reference command. The PAC generates a torque command to achieve reference tracking with the given PA command. This torque is called the PAC torque.

[0008] For this reason, it is understood that there is a need for a system for determining and correcting the pinion angle offset in order to eliminate multiple and combined errors in the PA while enabling the remaining error to remain within an acceptable error limit.

[0009] The United States patent document no. US10232873B2, another application included in the state of the art, discloses methods, apparatus, and articles of manufacture for identifying non-uniformity in a vehicle steering system. An exemplary apparatus comprises a first sensor to measure a steering wheel angle relative to a first universal joint, a second sensor to measure a pinion angle relative to a second universal joint, and a third sensor to measure a torque relative to a torsion bar. The apparatus further comprises a non-uniformity manager to determine a non-uniformity angle associated with a steering column, the non- uniformity angle based on the torque and comparing the steering wheel angle to the pinion angle, map the non-uniformity angle to a first position of the steering column, and determine an offset to adjust a steering response based on the first position.

[0010] Summary of the Invention

[0011] An object of the present invention is to realize a system for detecting and correcting the pinion angle deviation of an electric power steering system by calculating and measuring the uniformity errors and torsion bar errors due to the driver torque, which cause the pinion angle error, and by finding the intersections of the uniformity errors that may vary according to different inclination angles.

[0012] Detailed Description of the Invention “Steering Pinion Angle Finding and Correction System” realized to fulfil the objective of the present invention is shown in the figure attached, in which:

[0013] Figure l is a schematic view of the inventive system.

[0014] The components illustrated in the figures are individually numbered, where the numbers refer to the following:

[0015] 1. System

[0016] 2. Steering control unit

[0017] 3. Electrical control unit

[0018] A system (1) for detecting and correcting pinion angle deviation of the electric power steering system of a vehicle comprises; at least one steering control unit (2) which is positioned inside the vehicle and is configured to control and manage the electric power steering; and at least one electrical control unit (3) which is positioned inside the vehicle and is configured to communicate and exchange data with the units and components located in the vehicle; to run at least one software that automatically processes the data and generates meaningful results thereon; to receive and process data from the units and components located in the vehicle regarding the factors that will affect the pinion angle and to determine the pinion angle offset; to verify the pinion angle offset and to update the pinion angle by triggering the steering control unit (2) if the current pinion angle is not at the determined angle.

[0019] The steering control unit (2) included in the inventive system (1) is positioned inside the vehicle and is configured to control and manage the electric steering. The said steering control unit (2) is configured to adjust the steering pinion angle by being triggered by a command transmitted from the electrical control unit (3). The electrical control unit (3) included in the inventive system (1) is positioned inside the vehicle and is configured to communicate with the units and components located in the vehicle and to receive data related to the vehicle. The said electrical control unit (3) is configured to run at least one software that automatically processes data and generates meaningful results thereon. The electrical control unit (3) is configured to run the offset calculation logic through the software running thereon in order to determine the pinion angle offset by being triggered by turning on the vehicle ignition and ignition of the vehicle; to verify the current pinion angle by checking it through the steering control unit (2); and to trigger the steering control unit (2) in order to update the pinion angle.

[0020] The electrical control unit (3) is configured to, when performing offset calculation, define the first pinion angle as the steering angle; to define the offset of the calculated pinion angle as zero; to receive data regarding the vehicle and vehicle components; to check the offset determination conditions; to calculate sample offset values if the conditions are met; to determine if there are enough offset sample values; to average the offset values if there are enough offset values; and to define the obtained value as the pinion angle offset.

[0021] The electrical control unit (3) is configured to receive data in the form of steering wheel angle (SWA), driver steering torque, pinion angular speed, vehicle speed and pinion angle controller torque and to check whether the received data meets the conditions or not, while performing the condition check in the offset calculation. The electrical control unit (3) is configured to check whether the SWA is within a small window (SWA LIMIT) around a predefined angle (SWA SAMPLE ANGLE) or not (SWA SAMPLE ANGLE - SWA LIMIT < SWA SAMPLE ANGLE < SWA SAMPLE ANGLE + SWA LIMIT) during the condition check stage and whether the driver steering torque is less than a predefined torque threshold value or not; to check whether the filtered pinion angular speeds are below a predefined pinion angular speed threshold value or not by filtering the pinion angular speed in two different ways as low and high pass; and to check whether the vehicle speed is above a predefined vehicle speed threshold value or not and whether the pinion angle controller torque is equal to zero or not. The electrical control unit (3) is configured to proceed to the offset estimation stage if, as a result of the condition check stage, it determines that the SWA is within a small window around a predefined angle, the driver steering torque is less than a predefined torque threshold value, the filtered pinion angular speeds are below a predefined pinion angular speed threshold value, the vehicle speed is above a predefined vehicle speed threshold value and the pinion angle controller torque is equal to zero.

[0022] The electrical control unit (3) is configured to calculate the pinion angle offset by using the steering angle, pinion angle and driver steering torque values if it detects that all conditions for offset estimation are met. In the preferred embodiment of the invention, the electrical control unit (3) is configured to define the value obtained by subtracting the sum of the driver steering torque multiplied by the pinion angle and a torsion bar coefficient from the steering angle value as the pinion angle offset.

[0023] The electrical control unit (3) is configured to check the offset verification conditions when verifying the pinion angle offset and, if the conditions are met, to check whether the pinion angle offset has the same value as the pinion angle verification angle. The electrical control unit (3) is configured to add the pinion angle verification angle to the measured pinion angle if it detects that the pinion angle offset has the same value as the pinion angle verification angle. The electrical control unit (3) is configured to increase the pinion angle offset by a certain amount until it is equal to the calculated pinion angle verification angle if it detects that the pinion angle offset does not have the same value as the pinion angle verification angle. In the preferred embodiment of the invention, the electrical control unit (3) is configured to increase the pinion angle offset by a value obtained by multiplying a predefined l / N CORR parameter by the pinion angle offset. With this method, sudden jumps when correcting the pinion angle are avoided and it is guaranteed that the angle is corrected in small linear steps. The electrical control unit (3) is configured to add the increased pinion angle verification angle to the calculated pinion angle. The electrical control unit (3) is configured to check, when checking the offset verification conditions, whether there is any pinion angle or not, whether the verification is finished or not and whether the pinion angle controller torque is zero or not. The electrical control unit (3) is configured to trigger the steering control unit (2) in order for the determined pinion angle to be applied to the steering.

[0024] Industrial Application of the Invention

[0025] By means of the inventive system (1), it is enabled to detect, verify and correct the pinion angle deviation of the electric power steering system and thus to minimize the relative error change due to unevenness with respect to the inclination angle changes. The system (1) is developed to calculate and measure the uniformity errors caused by the steering system and to find the intersection of the uniformity errors, which can vary in phase and magnitude with respect to the tilt angle; in this way, it is enabled to minimize the relative error change due to unevenness with respect to the tilt angle variations.

[0026] In the inventive system (1), when the PA (pinion angle) is equal to a predefined angle, the error between SWA (steering wheel angle) and PA with respect to changes in the tilt angle is minimized. Therefore, taking this specific angle into account increases robustness to changes in steering wheel tilt angle.

[0027]

[0028] Figure 1; Graph showing the error between PA and SWA

[0029] The system (1) consists of two main components: PA offset calculation and PA offset correction. The PA offset calculation is determined by taking samples where the PA is equal to or very close to the predefined angle. In order to eliminate different sources of error during the sampling process, constraints are applied by controlling certain conditions. The PA offset correction is the part where the PA offset calculated under certain conditions is added to the measured pinion angle.

[0030] Within these basic concepts; it is possible to develop various embodiments of the inventive “Steering Pinion Angle Finding and Correction System (1)”; the invention cannot be limited to examples disclosed herein and it is essentially according to claims.

Claims

CLAIMS1. A system (1) for detecting and correcting pinion angle deviation of the electric power steering system of a vehicle characterized by at least one steering control unit (2) which is positioned inside the vehicle and is configured to control and manage the electric power steering; and at least one electrical control unit (3) which is positioned inside the vehicle and is configured to communicate and exchange data with the units and components located in the vehicle; to run at least one software that automatically processes the data and generates meaningful results thereon; to receive and process data from the units and components located in the vehicle regarding the factors that will affect the pinion angle and to determine the pinion angle offset; to verify the pinion angle offset and to update the pinion angle by triggering the steering control unit (2) if the current pinion angle is not at the determined angle.

2. A system (1) according to Claim 1; characterized by the steering control unit (2) which is positioned inside the vehicle and is configured to control and manage the electric steering.

3. A system (1) according to Claim 1 or 2; characterized by the steering control unit (2) which is configured to adjust the steering pinion angle by being triggered by a command transmitted from the electrical control unit (3).

4. A system (1) according to any one of the preceding claims; characterized by the electrical control unit (3) which is positioned inside the vehicle and is configured to communicate with the units and components located in the vehicle and to receive data related to the vehicle.

5. A system (1) according to any one of the preceding claims; characterized by the electrical control unit (3) which is configured to run at least one software that automatically processes data and generates meaningful results thereon.

6. A system (1) according to any one of the preceding claims; characterized by the electrical control unit (3) which is configured to run the offset calculation logic through the software running thereon in order to determine the pinion angle offset by being triggered by turning on the vehicle ignition and ignition of the vehicle; to verify the current pinion angle by checking it through the steering control unit (2); and to trigger the steering control unit (2) in order to update the pinion angle.

7. A system (1) according to any one of the preceding claims; characterized by the electrical control unit (3) which is configured to, when performing offset calculation, define the first pinion angle as the steering angle; to define the offset of the calculated pinion angle as zero; to receive data regarding the vehicle and vehicle components; to check the offset determination conditions; to calculate sample offset values if the conditions are met; to determine if there are enough offset sample values; to average the offset values if there are enough offset values; and to define the obtained value as the pinion angle offset.

8. A system (1) according to any one of the preceding claims; characterized by the electrical control unit (3) which is configured to receive data in the form of steering wheel angle, driver steering torque, pinion angular speed, vehicle speed and pinion angle controller torque and to check whether the received data meets the conditions or not, while performing the condition check in the offset calculation.

9. A system (1) according to any one of the preceding claims; characterized by the electrical control unit (3) which is configured to check whether the SWA is within a small window around a predefined angle or not during the conditioncheck stage and whether the driver steering torque is less than a predefined torque threshold value or not; to check whether the filtered pinion angular speeds are below a predefined pinion angular speed threshold value or not by filtering the pinion angular speed in two different ways as low and high pass; and to check whether the vehicle speed is above a predefined vehicle speed threshold value or not and whether the pinion angle controller torque is equal to zero or not.

10. A system (1) according to any one of the preceding claims; characterized by the electrical control unit (3) which is configured to proceed to the offset estimation stage if, as a result of the condition check stage, it determines that the SWA is within a small window around a predefined angle, the driver steering torque is less than a predefined torque threshold value, the filtered pinion angular speeds are below a predefined pinion angular speed threshold value, the vehicle speed is above a predefined vehicle speed threshold value and the pinion angle controller torque is equal to zero.

11. A system (1) according to any one of the preceding claims; characterized by the electrical control unit (3) which is configured to calculate the pinion angle offset by using the steering angle, pinion angle and driver steering torque values if it detects that all conditions for offset estimation are met.

12. A system (1) according to any one of the preceding claims; characterized by the electrical control unit (3) which is configured to define the value obtained by subtracting the sum of the driver steering torque multiplied by the pinion angle and a torsion bar coefficient from the steering angle value as the pinion angle offset.

13. A system (1) according to any one of the preceding claims; characterized by the electrical control unit (3) which is configured to check the offset verification conditions when verifying the pinion angle offset and, if the conditions are met, tocheck whether the pinion angle offset has the same value as the pinion angle verification angle.

14. A system (1) according to any one of the preceding claims; characterized by the electrical control unit (3) which is configured to add the pinion angle verification angle to the measured pinion angle if it detects that the pinion angle offset has the same value as the pinion angle verification angle.

15. A system (1) according to any one of the preceding claims; characterized by the electrical control unit (3) which is configured to increase the pinion angle offset by a certain amount until it is equal to the calculated pinion angle verification angle if it detects that the pinion angle offset does not have the same value as the pinion angle verification angle.

16. A system (1) according to any one of the preceding claims; characterized by the electrical control unit (3) which is configured to increase the pinion angle offset by a value obtained by multiplying a predefined l / N CORR parameter by the pinion angle offset.

17. A system (1) according to any one of the preceding claims; characterized by the electrical control unit (3) which is configured to add the increased pinion angle verification angle to the calculated pinion angle.

18. A system (1) according to any one of the preceding claims; characterized by the electrical control unit (3) which is configured to check, when checking the offset verification conditions, whether there is any pinion angle or not, whether the verification is finished or not and whether the pinion angle controller torque is zero or not.

19. A system (1) according to any one of the preceding claims; characterized by the electrical control unit (3) which.

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