JP2010264798A - Method for learning steering angle middle point - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for learning a steering angle middle point, by which the steering angle middle point can be learned accurately while avoiding an influence on a yaw rate sensor by the change of ambient temperature. <P>SOLUTION: When a yaw rate middle point correction condition is satisfied (Step S1→Yes), an EPSECU corrects a yaw rate middle point (Step S2) and measures the first ambient temperature Tmp1 of the yaw rate sensor (Step S3). When a steering angle middle point learning condition is satisfied (Step S4→Yes), the EPSECU measures the second ambient temperature Tmp2 of the yaw rate sensor (Step S5), and when a temperature difference (¾Tmp1-Tmp2¾) between the first ambient temperature Tmp1 and the second ambient temperature Tmp2 is equal to or lower than a predetermined temperature difference (Step S6→Yes), the steering angle middle point is learned (Step S7). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a steering angle midpoint learning method for learning a steering angle midpoint of a steering angle of a steering handle.

Vehicles equipped with an electric power steering (EPS) device that reduces a driver's steering force are known. Such vehicles include an EPS ECU (Electronic Control Unit) for controlling the electric power steering device. Is equipped.
In addition, when a vehicle stability assist (VSA) that controls the behavior of the vehicle by combining ABS (Anti Lock Brake System) or TCS (Traction Control System) is provided, the vehicle has a VSA ECU for controlling the behavior of the vehicle. ing.

The EPS ECU controls the electric power steering device in accordance with the behavior of the vehicle such as the traveling state of the vehicle (turning, straight traveling) and the vehicle speed, generates an auxiliary steering force to reduce the steering force of the driver, and steers the steering wheel. Reaction force control (control for applying reaction force to the operation of the steering handle) is executed in accordance with the steering angle.
Therefore, some vehicles including an electric power steering device have a vehicle behavior detection system including a sensor that detects the behavior of the vehicle. In order to detect turning of the vehicle, the vehicle behavior detection system includes a yaw rate sensor and a steering angle sensor as sensors for detecting the behavior of the vehicle.

As the rudder angle sensor, a sensor (for example, a rotary encoder) that uses a relative angle change amount of the steering handle as a detection value may be used. In this case, the EPS ECU can calculate the steering angle of the steering handle based on the amount of change in angle from the reference point, for example, when the steering handle is in the neutral position (hereinafter referred to as the steering angle midpoint).
Therefore, EPSECU needs to learn the steering angle midpoint. The yaw rate detected by the yaw rate sensor is used for learning the steering angle midpoint.
Therefore, in order to improve the accuracy of learning of the steering angle midpoint, the yaw rate sensor is required to detect the yaw rate with high accuracy.

  Some yaw rate sensors use semiconductor elements, and such a yaw rate sensor has a characteristic that a variation in a detection value accompanying a change in ambient temperature is large. Since the ambient temperature of the yaw rate sensor changes sequentially as the vehicle travels, it is preferable to appropriately correct the reference point in order to accurately detect the yaw rate of the vehicle in the traveling state.

  For example, in Patent Document 1, when the ignition switch is turned on, the provisional neutral position of the steering handle is set, and further, the provisional neutral position is appropriately corrected according to the subsequent traveling state of the vehicle. A steering angle neutral learning device that learns a neutral position (steering angle midpoint) is disclosed.

Japanese Patent No. 3728991

  According to the technique disclosed in Patent Document 1, it is determined that the vehicle is traveling straight on the basis of the detection value of the yaw rate sensor, but there is no description regarding correction of the reference point of the yaw rate sensor, and the change in the ambient temperature If the detected value of the yaw rate sensor fluctuates with this, there is a problem that the steering angle midpoint cannot be learned accurately.

In order to solve this problem, a configuration that appropriately corrects the reference point of the yaw rate sensor is suitable.
The yaw rate sensor can correct the reference point by determining the detected value when the yaw rate is not generated in the vehicle as the reference value. However, when the ECU ECU learns the steering angle midpoint when the ambient temperature of the yaw rate sensor when the reference point of the yaw rate sensor is corrected differs from the ambient temperature of the yaw rate sensor when the EPSECU learns the steering angle midpoint, The reference point of the yaw rate sensor may be different from the reference point when the reference point of the yaw rate sensor is corrected. When the EPS ECU learns the steering angle midpoint, the yaw rate sensor cannot accurately detect the yaw rate.

  Therefore, an object of the present invention is to provide a rudder angle midpoint learning method that can appropriately avoid the influence of a change in the ambient temperature of the yaw rate sensor and can accurately learn the rudder angle midpoint.

  In order to solve the above-mentioned problem, the present invention provides a procedure for correcting a reference point of a yaw rate sensor when a predetermined first condition is satisfied, and a surrounding of the yaw rate sensor when the first condition is satisfied. The procedure for measuring the temperature as the first ambient temperature, the procedure for measuring the ambient temperature of the yaw rate sensor when the predetermined second condition is satisfied as the second ambient temperature, and the second condition are satisfied And a procedure for determining a rudder angle as a rudder angle midpoint. When the second condition is satisfied, the rudder angle midpoint is determined only when the temperature difference between the first ambient temperature and the second ambient temperature is equal to or less than a predetermined temperature difference set in advance. It is characterized by that.

According to the present invention, only when the temperature difference between the ambient temperature of the yaw rate sensor when the first condition is satisfied and the ambient temperature of the yaw rate sensor when the second condition is satisfied is equal to or less than a predetermined temperature difference. It can be set as the steering angle midpoint learning method which can learn a steering angle midpoint.
Therefore, the temperature difference between the ambient temperature of the yaw rate sensor when the first condition is satisfied and the reference point of the yaw rate sensor is corrected and the ambient temperature of the yaw rate sensor when the second condition is satisfied is greater than the predetermined temperature difference. When the value is larger, the steering angle midpoint learning method that does not perform the steering angle midpoint learning even when the second condition is satisfied can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the influence by the change of the ambient temperature of a yaw rate sensor can be avoided suitably, and the steering angle midpoint learning method which can learn a steering angle midpoint accurately can be provided.

It is a figure which shows the steering mechanism of a vehicle. It is a flowchart which shows the procedure of rudder angle midpoint learning.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings as appropriate.
As shown in FIG. 1, the steering mechanism of the vehicle V includes a steering wheel (not shown) on a pinion shaft 22 that rotates together with a pinion gear (not shown) that meshes with a rack of a rack shaft 25 a of a rack and pinion mechanism 25. A steering handle 21 is attached via a shaft.
When the driver steers the steering handle 21, a pinion gear (not shown) rotates integrally with the pinion shaft 22 to move the rack shaft 25a in the left-right direction, and the left and right steered wheels 2R connected to the rack shaft 25a, 2L turns.

The vehicle V is provided with an electric power steering device 1.
The electric power steering device 1 includes an electric motor 23 that generates an auxiliary steering force (auxiliary steering torque) that reduces the steering force when the driver steers the steering handle 21 as an electric force and applies the steering force to the steering mechanism. ing.
The output shaft of the electric motor 23 meshes with the gear of the pinion shaft 22 via a gear (not shown). When the driver steers the steering handle 21, the output shaft of the electric motor 23 rotates to assist the pinion shaft 22. Steering force is reduced by generating steering torque.

Further, the electric power steering apparatus 1 includes an EPS ECU 20 that controls the electric power steering apparatus 1 by driving and controlling the electric motor 23.
The EPS ECU 20 includes a microcomputer (not shown), a microcomputer (ROM) including a ROM (Read Only Memory), a RAM (Random Access Memory), and peripheral circuits. The CPU executes a program stored in the ROM, for example. Thus, the drive of the electric motor 23 is controlled.

The VSA ECU 30 that controls the behavior of the vehicle V includes a microcomputer (not shown), a microcomputer having a ROM, a RAM, and the like, and a peripheral circuit. The CPU executes a program stored in the ROM, for example. To control. For example, the VSA ECU 30 is disposed in the engine room 3.
The EPS ECU 20 and the VSA ECU 30 are connected to each other by, for example, a CAN (Controller Area Network) protocol network (hereinafter referred to as a CAN network) and can exchange data with each other.

A yaw rate sensor 18 and a temperature sensor 19 are incorporated in the VSA ECU 30.
The yaw rate sensor 18 detects the yaw rate generated in the vehicle V and outputs a yaw rate signal Ys.
Further, the temperature sensor 19 measures the temperature in the engine room 3 where the VSA ECU 30 is arranged, and outputs a temperature signal Tms.
The yaw rate signal Ys and the temperature signal Tms are input to the EPS ECU 20 via the CAN network, and the EPS ECU 20 calculates the yaw rate generated in the vehicle V and the temperature in the engine room 3.

  Since the yaw rate sensor 18 is incorporated in the VSA ECU 30 disposed in the engine room 3, the yaw rate sensor 18 is disposed in the engine room 3, and the temperature in the engine room 3 corresponds to the ambient temperature of the yaw rate sensor 18. Therefore, the temperature sensor 19 measures the ambient temperature of the yaw rate sensor 18. The EPS ECU 20 calculates the ambient temperature of the yaw rate sensor 18 based on the temperature signal Tms when the temperature sensor 19 measures the ambient temperature of the yaw rate sensor 18.

  A torque sensor 16 is attached to the pinion shaft 22 to detect a steering torque when the driver steers the steering handle 21 and outputs a torque signal Ts. The torque signal Ts is input to the EPS ECU 20, and the EPS ECU 20 calculates the steering torque generated in the pinion shaft 22.

Further, a vehicle speed sensor 17 is connected to the EPSECU 20.
The vehicle speed sensor 17 detects the vehicle speed as the number of pulses per unit time, and outputs a vehicle speed signal Vs.
The vehicle speed signal Vs is input to the EPS ECU 20, and the EPS ECU 20 calculates the vehicle speed of the vehicle V.

Further, the vehicle V is provided with a steering angle sensor 24 for detecting the steering angle of the steering handle 21.
The rudder angle sensor 24 is constituted by, for example, a sensor that detects an amount of change in angle when the driver steers the steering handle 21, and outputs an angle signal θs. The angle signal θs is input to the EPSECU 20, and the EPSECU 20 calculates the steering angle of the steering handle 21 based on the angle signal θs.

The EPS ECU 20 sets the auxiliary steering torque output from the electric motor 23 based on the calculated vehicle speed, steering torque, and the like, and supplies the electric motor 23 with a drive current Ic that rotates the electric motor 23 so as to output the set auxiliary steering torque. To do.
In the electric motor 23, the output shaft is rotationally driven by the supplied drive current Ic, and an auxiliary steering torque is applied to the pinion shaft 22 to reduce the steering force.
Further, the EPS ECU 20 executes reaction force control for applying a steering reaction force to the steering handle 21 based on the calculated vehicle speed, steering torque, steering angle, yaw rate, and the like.

  In the present embodiment, the EPS ECU 20 is configured to detect the behavior of the vehicle V based on the detection values of the vehicle speed sensor 17, the steering angle sensor 24, and the yaw rate sensor 18, and the vehicle speed sensor 17, the steering angle sensor 24, and the yaw rate are detected. The vehicle behavior detection system 5 is configured including the sensor 18 and the EPS ECU 20.

  If the steering angle sensor 24 is a sensor that detects the amount of change in the angle of the steering handle 21, the EPS ECU 20 learns that the steering handle 21 is in the neutral position (steering angle midpoint), and from the steering angle midpoint. Based on the angle change amount, the steering angle of the steering handle 21 is calculated. Therefore, EPSECU 20 needs to learn the steering angle midpoint. Hereinafter, learning of the steering angle midpoint by the EPS ECU 20 is referred to as steering angle midpoint learning.

  It is preferable that the EPS ECU 20 periodically learns the steering angle midpoint in order to detect the steering angle of the steering handle 21 with high accuracy.

  Since the vehicle V goes straight when the steering handle 21 is at the rudder angle midpoint, the EPS ECU 20 is turning the rudder angle when the yaw rate is not generated in the traveling vehicle V in the rudder angle midpoint learning. Decide with a point.

For example, the EPS ECU 20 determines that the steering handle 21 is at the steering angle midpoint when the following condition A is satisfied, and learns the steering angle midpoint.
<< Condition A >>
1. The vehicle speed of the vehicle V is equal to or greater than a predetermined value VEL1.
2. The yaw rate generated in the vehicle V is equal to or less than a predetermined value YAW1.
3. The steering torque generated on the pinion shaft 22 is within a predetermined value TRQ1.
4). The fluctuation range of the rudder angle is ΔDEG1 or less.
5.1. ~ 4. The state continues for time TIM1.

Further, since the detected value of the yaw rate detected by the yaw rate sensor 18 is used for the steering angle midpoint learning of the EPS ECU 20, the reference of the yaw rate sensor 18 is used in order to improve the accuracy of the detected value of the yaw rate of the yaw rate sensor 18. A configuration in which the points are corrected appropriately is preferable. With this configuration, the accuracy of the steering angle midpoint learning of the EPS ECU 20 can be improved.
Hereinafter, the reference point of the yaw rate sensor 18 is referred to as a yaw rate midpoint. The middle point of the yaw rate is a detection value detected by the yaw rate sensor 18 when no yaw rate is generated in the vehicle V.
Further, correcting the midpoint (reference point) of the yaw rate is hereinafter referred to as midpoint correction (reference point correction) and correcting the midpoint of the yaw rate sensor is referred to as yaw rate midpoint correction.

For example, the EPS ECU 20 determines the detected value detected by the yaw rate sensor 18 when the following condition B is satisfied as the yaw rate midpoint and corrects the yaw rate midpoint.
<< Condition B >>
When the vehicle V has been stopped for a predetermined time ΔTst and a predetermined time ΔTyaw shorter than the predetermined time ΔTst has elapsed since the vehicle V stopped.

Further, when the vehicle V is traveling, the EPS ECU 20 determines the detected value detected by the yaw rate sensor 18 when the following condition C is satisfied as the yaw rate midpoint, and corrects the yaw rate midpoint.
<< Condition C >>
1. The fluctuation range of the yaw rate is within a predetermined value ΔYAW2.
2. The steering torque generated on the pinion shaft 22 is within a predetermined value TRQ2.
3. The fluctuation range of the steering angle is within a predetermined value Δθ2.
4). The vehicle speed is equal to or higher than a predetermined value VEL2.
5.1. ~ 4. State continues for time TIM2.

  In addition, each predetermined value (VEL1, YAW1, TRQ1, ΔDEG1, TIM1, ΔYAW2, TRQ2, Δθ2, VEL2, TIM2) of the condition A and the condition C, and the predetermined times ΔTst and ΔTyaw when the vehicle V is stopped are: What is necessary is just to set suitably based on the performance requested | required of the vehicle V, the sensitivity of the steering angle sensor 24, and the yaw rate sensor 18, etc.

  The EPS ECU 20 corrects the yaw rate midpoint when either of the above-described condition B or condition C is satisfied, and further, when the condition A is satisfied, the steering ECU is adjusting the steering angle based on the detected value of the yaw rate sensor 18 corrected by the yaw rate midpoint. Point learning. Thus, EPSECU 20 can calculate the steering angle of the steering handle 21 with high accuracy by appropriately learning the steering angle midpoint. The EPS ECU 20 can suitably control the reaction force based on the steering angle of the steering handle 21 with high accuracy.

However, since the yaw rate sensor 18 has the characteristic that the variation of the detection value accompanying the change in the ambient temperature is large, the ambient temperature of the yaw rate sensor 18 when the yaw rate midpoint is corrected is the value when the EPS ECU 20 learns the steering angle midpoint. If the ambient temperature of the yaw rate sensor 18 differs greatly, the detection value of the yaw rate sensor 18 fluctuates, and the EPS ECU 20 cannot accurately detect the yaw rate generated in the vehicle V when learning the steering angle midpoint.
That is, the yaw rate midpoint of the yaw rate sensor 18 when the yaw rate midpoint is corrected differs from the yaw rate midpoint of the yaw rate sensor 18 when the EPSECU 20 learns the steering angle midpoint, and the yaw rate when the EPSECU 20 learns the steering angle midpoint A midpoint shift occurs in the sensor 18.

As described above, the yaw rate sensor 18 is disposed in the engine room 3 of the vehicle V.
Therefore, when the temperature in the engine room 3 increases due to the heat of the engine (not shown), the ambient temperature of the yaw rate sensor 18 increases. If the yaw rate midpoint correction is performed when the temperature in the engine room 3 is high, the midpoint shift occurs in the yaw rate sensor 18 when the temperature in the engine room 3 becomes low.

For example, when the driver steers the steering handle 21 and the vehicle V is turning, the yaw rate sensor 18 in which the midpoint deviation has occurred outputs a detection value indicating that no yaw rate has occurred. Then, EPSECU 20 determines that the vehicle V is traveling straight despite the vehicle V turning, and learns the steering angle midpoint.
That is, the EPS ECU 20 determines that the steering wheel is at the steering angle midpoint and learns the steering angle midpoint when the steering handle 21 is being steered by the driver.
As described above, when the midpoint deviation occurs in the yaw rate sensor 18 when the EPSECU 20 learns the steering angle midpoint, the accuracy of the steering angle midpoint learning of the EPSECU 20 decreases.

Therefore, the EPS ECU 20 according to the present embodiment determines a difference between the ambient temperature of the yaw rate sensor 18 when the yaw rate midpoint is corrected and the ambient temperature of the yaw rate sensor 18 when learning the steering angle midpoint as a predetermined temperature difference. Is exceeded, it is determined that a midpoint shift has occurred in the yaw rate sensor 18 when learning the steering angle midpoint, and the steering angle midpoint learning is not performed.
The predetermined temperature difference set in advance may be, for example, a temperature difference at which it is recognized that no midpoint deviation occurs in the yaw rate sensor 18 when the EPS ECU 20 learns the steering angle midpoint, and is based on the performance of the yaw rate sensor 18 and the like. What is necessary is just to set suitably.

With reference to FIG. 2, the procedure by which the EPS ECU 20 performs the steering angle midpoint learning will be described (see FIG. 1 as appropriate).
For example, this procedure may be incorporated as a subroutine in a program executed by the EPSECU 20 and executed at a predetermined timing (for example, a predetermined time interval such as 100 msec).

As shown in FIG. 2, if the yaw rate midpoint correction condition is not satisfied (step S1 → No), the EPS ECU 20 advances the process to step S4, but if the yaw rate midpoint correction condition is satisfied (step S1 → Yes), The middle point of the yaw rate is corrected (step S2).
The EPS ECU 20 determines that the yaw rate midpoint correction condition is satisfied when either the above-described condition B or condition C is satisfied, and the yaw rate midpoint correction is performed when neither the condition B nor the condition C is satisfied. Assume that the condition is not satisfied.
The yaw rate midpoint correction condition corresponds to the first condition described in the claims.

Further, EPSECU 20 calculates the temperature in engine room 3 (first ambient temperature Tmp1) based on temperature signal Tms input from temperature sensor 19.
The temperature signal Tms at this time is a temperature signal that the temperature sensor 19 measures and outputs the temperature (first ambient temperature Tmp1) in the engine room 3 when the yaw rate midpoint correction condition is satisfied. The first ambient temperature Tmp1 is measured (step S3).

EPSECU 20 ends the process when the steering angle midpoint learning condition is not satisfied (step S4 → No), but when the steering angle midpoint learning condition is satisfied (step S4 → Yes), input from temperature sensor 19 Based on the temperature signal Tms, the current temperature in the engine room 3 (second ambient temperature Tmp2) is calculated.
The temperature signal Tms at this time is a temperature signal that the temperature sensor 19 measures and outputs the temperature in the engine room 3 (second ambient temperature Tmp2) when the steering angle midpoint learning condition is satisfied. Measures the second ambient temperature Tmp2 (step S5).

The EPS ECU 20 assumes that the steering angle midpoint learning condition is satisfied when the above-described condition A is satisfied, and that the steering angle midpoint learning condition is not satisfied when the condition A is not satisfied.
The steering angle midpoint learning condition corresponds to a second condition described in the claims.

  The EPS ECU 20 compares the first ambient temperature Tmp1, which is the temperature in the engine room 3 immediately after the yaw rate midpoint correction, and the second ambient temperature Tmp2, which is the temperature in the engine room 3 when the steering angle midpoint learning condition is satisfied. When the temperature difference (| Tmp1-Tmp2 |: absolute value of the difference between Tmp1 and Tmp2) is calculated and the calculated temperature difference (| Tmp1-Tmp2 |) is less than or equal to a predetermined temperature difference set in advance (step S6 → Yes), the steering angle midpoint is learned (step S7), but when the calculated temperature difference is larger than the predetermined temperature difference set in advance (step S6 → No), the process is terminated.

  As described above, the yaw rate sensor 18 (see FIG. 1) has a large variation in the detected value due to the change in the ambient temperature. Therefore, the engine room 3 (see FIG. 1) immediately after the EPS ECU 20 (see FIG. 1) corrects the midpoint of the yaw rate. If the temperature difference between the first ambient temperature Tmp1 that is the temperature in the engine room 3 and the second ambient temperature Tmp2 that is the temperature in the engine room 3 when the EPS ECU 20 learns the steering angle midpoint is large, the midpoint correction of the yaw rate is performed. The midpoint of the yaw rate at the time is different from the midpoint of the yaw rate at which the steering angle midpoint learning is performed, and a midpoint shift occurs in the yaw rate sensor 18 when the EPS ECU 20 learns the steering angle midpoint.

As described above, if the midpoint deviation occurs in the yaw rate sensor 18 (see FIG. 1) when the EPSECU 20 (see FIG. 1) learns the steering angle midpoint, the accuracy of the steering angle midpoint learning of the EPSECU 20 decreases.
Therefore, the EPS ECU 20 according to the present embodiment performs the first ambient temperature Tmp1, which is the temperature in the engine room 3 (see FIG. 1) when the yaw rate midpoint is corrected in step S6 of FIG. 2, and the steering angle midpoint learning condition. When the temperature difference (| Tmp1-Tmp2 |) of the second ambient temperature Tmp2, which is the temperature in the engine room 3 when the above is established, is larger than a predetermined temperature difference set in advance, the steering angle midpoint learning is performed. Even if it is determined that a midpoint shift occurs in the yaw rate sensor 18 and the steering angle midpoint learning condition is satisfied, the steering angle midpoint is not learned.

  In other words, the EPS ECU 20 (see FIG. 1) is configured so that the engine when the steering angle midpoint learning condition is satisfied and the first ambient temperature Tmp1 that is the temperature in the engine room 3 (see FIG. 1) when the yaw rate midpoint correction is performed. The steering angle midpoint is learned only when the temperature difference (| Tmp1-Tmp2 |) of the second ambient temperature Tmp2, which is the temperature in the room 3, is equal to or smaller than a predetermined temperature difference set in advance.

With this configuration, the EPS ECU 20 (see FIG. 1) allows the temperature (first ambient temperature Tmp1) in the engine room 3 (see FIG. 1) when the yaw rate midpoint correction is performed and the engine room 3 when learning the steering angle midpoint. The internal temperature (second ambient temperature Tmp2) can be made close. That is, the EPS ECU 20 can set the ambient temperature of the yaw rate sensor 18 (see FIG. 1) when the yaw rate midpoint is corrected and the ambient temperature of the yaw rate sensor 18 when learning the steering angle midpoint to a close temperature. Then, the yaw rate midpoint of the yaw rate sensor 18 when the yaw rate midpoint is corrected and the yaw rate midpoint of the yaw rate sensor 18 when learning the steering angle midpoint can be made close to each other. Therefore, the midpoint deviation generated in the yaw rate sensor 18 when the EPS ECU 20 learns the steering angle midpoint can be reduced.
Thus, EPSECU 20 can avoid the influence by the change of the ambient temperature of yaw rate sensor 18 suitably, and can make small the midpoint shift which generate | occur | produces in yaw rate sensor 18 at the time of steering angle midpoint learning.

If the midpoint deviation generated in the yaw rate sensor 18 (see FIG. 1) during the steering angle midpoint learning is small, the influence of the EPS ECU 20 (see FIG. 1) on the steering angle midpoint learning is also small, and the midpoint deviation is small. The accuracy of the steering angle midpoint learning of the EPS ECU 20 is improved.
And if the precision of rudder angle midpoint learning improves, EPSECU20 can improve the system of reaction force control, and there exists the outstanding effect that a driver | operator can suppress suitably feeling uncomfortable.
As described above, the EPS ECU 20 according to the present embodiment can appropriately avoid the influence due to the change in the ambient temperature of the yaw rate sensor 18 and improve the accuracy of the steering angle midpoint learning.

18 Yaw rate sensor 19 Temperature sensor 20 EPSECU
Tmp1 1st ambient temperature Tmp2 2nd ambient temperature V Vehicle

Claims (1)

Correcting the reference point of the yaw rate sensor when the predetermined first condition is satisfied;
Measuring the ambient temperature of the yaw rate sensor when the first condition is satisfied as a first ambient temperature;
A procedure for measuring an ambient temperature of the yaw rate sensor when a predetermined second condition is satisfied as a second ambient temperature;
A rudder angle midpoint learning method comprising: determining a rudder angle when the second condition is satisfied as a rudder angle midpoint;
When the second condition is satisfied, the rudder angle midpoint is determined only when a temperature difference between the first ambient temperature and the second ambient temperature is equal to or less than a predetermined temperature difference set in advance. A rudder angle midpoint learning method as a feature.

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