JP2013028244A - Vehicular control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular control device which can perform all controls requiring steering angle information by estimating a steering angle from wheel speed and allowing even a vehicle not containing a steering angle detection means to estimate a steering angle.SOLUTION: The device is provided with an estimated steering angle calculation means which includes a left wheel speed detection means for detecting left side wheel speed, a right wheel speed detection means for detecting right side wheel speed, a right/left difference calculation means for calculating right and left wheel rotation difference from left wheel speed and right wheel speed, a vehicle speed calculation means for calculating vehicle speed from left wheel speed and right wheel speed, an estimated steering angle calculation means for calculating an estimated steering angle on the basis of the right/left difference and vehicle speed, and an estimated steering angle update determination means for determining the execution of an update of a steering angle.

Description

  The present invention relates to a vehicle control device, and in particular, a vehicle control capable of estimating a steering angle in a vehicle not equipped with a steering angle detection means and executing all controls requiring steering angle information. Relates to the device.

In a four-wheel drive type vehicle that controls the driving force of the auxiliary driving wheel relative to the main driving wheel, the driving force distribution of the auxiliary driving shaft to the main driving wheel according to the front-rear wheel rotational speed difference (ΔN) by the vehicle control device. In many cases, the amount is determined (feedback control) (Japanese Patent Laid-Open No. 2007-131193).
In order to improve four-wheel drive performance, it is necessary to add the determination of the driving force distribution amount (feed forward control) according to the engine torque, but in order to adopt feed forward control, the steering angle is detected. There is a need to. This reduces the amount of driving force distribution when the steering angle is large, suppresses the occurrence of tight corner braking, prevents deterioration of turning performance, noise, vibration and overload to the drive system associated with tight corner braking. This is because of this (Japanese Patent Laid-Open No. 2011-57154, Japanese Patent Laid-Open No. 6-87342).
When performing control that requires steering angle information as described above, it is necessary to provide a steering angle detection means in order to acquire the steering angle information. However, in a vehicle that is not equipped with the steering angle detection means, the steering angle information cannot be acquired, and therefore control that requires the steering angle information cannot be performed. Techniques for estimating and obtaining the steering angle from the detection information of other detection means without using the steering angle detection means include the following.

  Japanese Patent Laid-Open No. 2003-276635 discloses a technique for estimating the steering angle by multiplying the rotation change amount from the rotation angle of the electric power steering motor when the vehicle is in a straight traveling state by 1 / (reduction ratio). It is disclosed. Japanese Patent Laid-Open No. 2008-49914 associates a known absolute rudder angle with a relative rudder angle calculated from the rotation angle of the electric power steering motor at this time when the steering mechanism is in a steering limit state or a neutral state. Thus, a technique for estimating the steering angle is disclosed. In JP 2010-58661 A, an absolute steering angle is calculated from the maximum relative steering angle / minimum relative steering angle calculated from the rotation angle of the electric power steering motor and a preset total steering angle range, and the steering angle is calculated. A technique for estimating the above is disclosed.

JP 2007-131193 A JP 2011-57154 A JP-A-6-87342 JP 2003-276635 A JP 2008-49914 A JP 2010-58661 A

However, the techniques of Patent Documents 4 to 6 have the following problems.
The technique disclosed in Japanese Patent Laid-Open No. 2003-276635 is based on the condition that the vehicle is traveling straight and the neutral position. Therefore, the steering angle cannot be detected until the vehicle is traveling straight forward and the neutral position is detected. The technique disclosed in Japanese Patent Application Laid-Open No. 2008-49914 requires a large number of detection means, and it is necessary to set the rack end absolute rudder angle and the neutral absolute rudder angle in advance until the steering limit state or the neutral state is determined. Cannot detect the steering angle. In the technique disclosed in Japanese Patent Application Laid-Open No. 2010-58661, it is necessary to set the entire steering angle range in advance, and the steering angle cannot be detected in a state where the steering is not turned off after starting.

  The present invention can estimate the steering angle from the wheel speed, and can estimate the steering angle even in a vehicle not equipped with the steering angle detection means and execute all the controls that require the steering angle information. An object of the present invention is to realize a vehicular control device.

  The present invention includes a left wheel speed detecting means for detecting a left wheel speed of a vehicle, a right wheel speed detecting means for detecting a right wheel speed of the vehicle, a left wheel speed detected by the left wheel speed detecting means, and the right wheel Left / right wheel difference calculating means for calculating the left / right wheel rotation difference from the right wheel speed detected by the wheel speed detecting means, and the left wheel speed and right wheel speed detecting means detected by the left wheel speed detecting means. Vehicle speed calculation means for calculating the vehicle speed from the right wheel speed, estimation for calculating an estimated steering angle based on the left and right wheel rotation difference calculated by the left and right wheel difference calculation means and the vehicle speed calculated by the vehicle speed calculation means There is provided an estimated steering angle calculation means comprising steering angle calculation means and estimated steering angle update determination means for determining whether or not to update the estimated steering angle calculated by the estimated steering angle calculation means.

In the present invention, the steering angle can be estimated from the wheel speed without using the steering angle detection means. Accordingly, it is possible to estimate the steering angle and execute all the controls that require the steering angle information even in a vehicle that is not equipped with the steering angle detection means.
Since the wheel speed detecting means for detecting the wheel speed is mounted on almost all vehicles, the steering angle can be estimated without mounting a new detecting means. Since the steering angle is estimated from the wheel speed, the steering angle can be estimated by only a simple calculation process.

FIG. 1 is a block diagram of steering angle estimation control of the vehicle control device. Example 1 FIG. 2 is a flowchart of the estimated steering angle update determination process. Example 1 FIG. 3 is a table showing the estimated steering angle update conditions. Example 1 FIG. 4 is a system block diagram of a four-wheel drive vehicle control apparatus. Example 1 FIG. 5 is a system input / output diagram of a four-wheel drive vehicle control apparatus. Example 1 FIG. 6 is a block diagram of the steering angle process of the vehicle control device. (Example 2) FIG. 7 is a block diagram of the steering angle estimation control of the vehicle control device. (Example 2) FIG. 8 is a flowchart of the estimated steering angle update determination process. (Example 2) FIG. 9 is a table showing the estimated steering angle update conditions. (Example 2) FIG. 10 is a flowchart of the midpoint learning process. (Example 2) FIG. 11 is a table showing the midpoint learning conditions. (Example 2) FIG. 12 is a diagram showing the relationship between the electrical angle and the resolver signal when the ignition switch is on (IGON). (Example 2) FIG. 13 is a system input / output diagram of a four-wheel drive vehicle control apparatus. (Example 2) FIG. 14 is a flowchart of the midpoint learning process. (Modification 1) FIG. 15 is a table showing the midpoint learning conditions. (Modification 1)

  Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 show Embodiment 1 of the present invention. In FIG. 4, 1 is a four-wheel drive vehicle. This vehicle 1 has an engine 2 and a transmission 3 mounted horizontally in a front portion, and the front differential 4 is connected to the inner ends of a front left axle 5 and a front right axle 6 which are main drive shafts, and a front left axle. The front left wheel 7 and the front right wheel 8 which are main drive wheels are attached to the outer ends of the front right axle 5 and the front right axle 6, respectively.
In the vehicle 1, the transfer 9 is connected to the transmission 3, and the front end of the propeller shaft 10 is connected to the transfer 9. The propeller shaft 10 has a rear end coupled to a rear differential 12 via a torque distribution clutch 11. The rear differential 12 is connected with inner ends of a rear left axle 13 and a rear right axle 14 which are auxiliary drive shafts, and is provided with auxiliary drive wheels at outer ends of the rear left axle 13 and the rear right axle 14, respectively. A rear left wheel 15 and a rear right wheel 16 are attached.
The driving torque generated by the engine 2 is transmitted to the front left axle 5 and the front right axle 6 via the transmission 3 and the front differential 4 to drive the front left wheel 7 and the front right wheel 8 as main driving wheels. The driving torque generated by the engine 2 is taken out by the transfer 9 and is transmitted by the propeller shaft 10 to the torque distribution clutch 11 which is a driving force distribution means. The torque distribution clutch 11 distributes the driving force from the engine 2 to the front left wheel 7, the front right wheel 8, the rear left wheel 15, and the rear right wheel 16 according to the traveling state of the vehicle 1. The driving force distributed to the rear left wheel 15 and the rear right wheel 16 by the torque distribution clutch 11 is transmitted to the rear left axle 13 and the rear right axle 14 via the rear differential 12, and the rear left wheel The wheel 15 and the rear right wheel 16 are driven as auxiliary driving wheels.

The torque distribution clutch 11 is connected to a vehicle control device 17 as shown in FIG. The vehicle control device 17 includes a driving force distribution control unit 18, a drive system protection control unit 19, a vehicle motion coordination control unit 20, a CAN (in-vehicle LAN) communication function unit 21, a fail safe control unit 22, Self-diagnosis means 23. A drive selection switch 24 is directly connected to the vehicle control device 17, and an engine control device 25, a transmission control device 26, an antilock brake control device 27, an electric power steering control device 28, and a combination meter. 29 is connected by CAN communication (in-vehicle LAN).
From the drive selection switch 24, four-wheel drive information by operation of the four-wheel drive switch 30 and lock information by operation of the lock switch 31 are input. From the engine control device 25, accelerator opening information by the accelerator opening detecting means 33 provided on the accelerator pedal 32, stop lamp switch information by the stop lamp switch 35 provided on the brake pedal 34 (see FIG. 4), Engine speed information is input. Shift position information is input from the transmission control device 26.
From the anti-lock brake control device 27, the front left wheel speed information indicating the rotational speed of the front left wheel 7 detected by the front left wheel speed detecting means 36 and the front right wheel 8 detected by the front right wheel speed detecting means 37 are displayed. The front right wheel speed information indicating the rotational speed of the vehicle, the rear left wheel speed information indicating the rotational speed of the rear left wheel 15 detected by the rear left wheel speed detecting means 38, and the rear right wheel speed detecting means 39 The detected rear right wheel speed information indicating the rotational speed of the rear right wheel 16 is input, and anti-lock brake control execution information is input.
The electric power steering control device 28 (EPS: electronic power steering) controls the vehicle 1 so that the steering force of the vehicle 1 is reduced by the motor, and the rotation angle of the motor 41 that assists the steering of the steering wheel 40 by the driver. Rotation angle information from the resolver 42 that detects this is input.
The vehicle control device 17 controls the fastening force of the torque distribution clutch 11 so that the driving force distribution amount determined by the driving force distribution control means 18 is obtained based on various pieces of input information, and the front left wheel 7 and The driving force of the engine 2 is distributed to the front right wheel 8, the rear left wheel 15, and the rear right wheel 16 according to the running state. Further, the vehicle control device 17 controls the driving force / brake of the motor 41 that assists the steering by the vehicle motion cooperative control means 20 and the fastening force of the engine output / torque distribution clutch 11 in a coordinated manner to stabilize the traveling of the vehicle 1. Let Further, the vehicle control device 17 outputs the drive mode information to the engine control device 25 by the CAN communication function means 21, and outputs the ignition request information of the four-wheel drive indicator light / lock display warning light to the combination meter 29 for driving. Processing is performed by the system protection control means 19, fail-safe control means 22, and self-diagnosis means 23.

The vehicle control device 17 includes estimated steering angle calculation means 43 that estimates the steering angle from the wheel speed without using the steering angle detection means. The estimated steering angle calculation means 43 detects the front left wheel speed detection means 36 for detecting the front left wheel speed of the front left wheel 7 and the front right wheel speed of the front right wheel 8 as shown in FIG. The front right wheel speed detecting means 37, the rear left wheel speed detecting means 38 for detecting the rear left wheel speed of the rear left wheel 15 and the rear for detecting the rear right wheel speed of the rear right wheel 16. Side right wheel speed detection means 39.
The estimated steering angle calculation means 43 includes a front left / right wheel difference calculation means 44, a rear left / right wheel difference calculation means 45, a vehicle speed calculation means 46, an estimated steering angle calculation means 47, and an estimated steering angle update determination means 48. I have.
The front left / right wheel difference calculating means 44 rotates the front left / right wheels based on the front left wheel speed detected by the front left wheel speed detecting means 36 and the front right wheel speed detected by the front right wheel speed detecting means 37. Calculate the difference. The rear left and right wheel difference calculating means 45 includes a rear left wheel speed detected by the rear left wheel speed detecting means 38 and a rear right wheel speed detected by the rear right wheel speed detecting means 39. From the above, the rear left and right wheel rotation difference is calculated.
The vehicle speed calculation means 46 calculates the rear side from the rear left wheel speed detected by the rear left wheel speed detection means 38 and the rear right wheel speed detected by the rear right wheel speed detection means 39. The vehicle speed of the wheels 15 and 16 is calculated. The estimated steering angle calculator 47 is based on the rear left and right wheel rotation difference calculated by the rear left and right wheel difference calculator 45 and the vehicle speed calculated by the vehicle speed calculator 46.
-Estimated steering angle = Rear left / right wheel rotation difference / (Conversion coefficient * Vehicle speed)
The estimated steering angle is calculated from the following formula. Note that the conversion coefficient in the equation is a constant value determined by the vehicle 1.
The estimated steering angle update determination means 48 determines whether or not to update the estimated steering angle calculated by the estimated steering angle calculation means 47.
The estimated steering angle update determination means 48 includes extremely low speed determination means 49 for determining whether or not the vehicle 1 is in an extremely low speed traveling state. The estimated steering angle update determining means 48 does not update the estimated steering angle when the extremely low speed determining means 49 determines that the vehicle 1 is in an extremely low speed traveling state.
The estimated steering angle update determining means 48 includes a grip limit determining means 50 for determining whether or not the vehicle 1 is at the grip limit. The estimated steering angle update determining unit 48 does not update the estimated steering angle when the grip limit determining unit 50 determines that the vehicle 1 is at the grip limit.
Further, the estimated steering angle update determining means 48 does not update the estimated steering angle when the rate of change of the estimated steering angle calculated by the estimated steering angle calculating means 47 is larger than a preset value.

Next, the operation will be described.
The vehicle control device 17 calculates the front left / right wheel rotation difference by the front left / right wheel difference calculation means 44, calculates the rear left / right wheel rotation difference by the rear left / right wheel difference calculation means 45, and calculates the vehicle speed by the vehicle speed calculation means 46. The estimated steering angle is calculated by the estimated steering angle calculating means 47, and the estimated steering angle update determining means 48 performs the estimated steering angle update determining process.
As shown in FIG. 2, when the estimated steering angle update determination process by the estimated steering angle update determination means 48 is started (A01), the vehicle control device 17 determines extremely low speed (A02), and estimates the estimated steering angle reliability. (A03), the grip limit is determined (A04), and it is determined whether the estimated steering angle update condition is satisfied (A05).
In the extremely low speed determination (A02), it is determined whether or not the vehicle speed is equal to or lower than a threshold value (when the vehicle speed is equal to or lower than the threshold value, it is determined as an extremely low speed traveling state). In the determination of the estimated steering angle reliability (A03), it is determined whether or not the rate of change of the estimated steering angle is equal to or greater than a threshold value (when it is equal to or greater than the threshold value, it is determined that there is no reliability). In the determination of the grip limit (A04), it is determined whether or not the difference between the front left / right wheel rotation difference and the rear left / right wheel rotation difference is equal to or greater than a threshold value (when it is equal to or greater than the threshold value, the grip limit is determined).
In the determination of the estimated steering angle update condition (A05), as shown in FIG. 3, it is determined whether all the conditions of extremely low speed determination, estimated steering angle reliability determination, and grip limit determination are satisfied. (If the speed is not extremely low, the estimated steering angle is not distrusted, and the grip limit is not met, the condition is met)
If the determination (A05) is YES, the estimated steering angle is updated (A06), and the estimated steering angle update determination process is terminated (A07). If the determination (A05) is NO, the previous value is held without updating the estimated steering angle (A08), and the estimated steering angle update determination process is terminated (A07).
The estimated steering angle calculation unit 43 outputs the estimated steering angle obtained by the determination process of the estimated steering angle update determination unit 48 to the next stage as the steering angle of the vehicle 1.

Thus, the vehicle control device 17 is detected by the front left wheel speed detecting means 36, the front right wheel speed detecting means 37, the rear left wheel speed detecting means 38, and the rear right wheel speed detecting means 39. The steering angle can be estimated from the wheel speed. Therefore, the vehicle control device 17 can estimate the steering angle and perform feed-forward control of the four-wheel drive control even in a vehicle not equipped with the steering angle detection means. Further, not only four-wheel drive control but all control that requires steering angle information can be executed.
Since the wheel speed detecting means for detecting the wheel speed is mounted on almost all vehicles, the steering angle can be estimated without mounting a new detecting means. Since the vehicle control device 17 estimates the steering angle from the wheel speed, the steering angle can be estimated only by a simple calculation process as shown in FIG.
When the vehicle 1 is traveling at an extremely low speed, the vehicle control device 17 has a poor steering angle estimation accuracy (the denominator (conversion coefficient * vehicle speed) of the estimated steering angle calculation formula approaches zero, and the calculated value tends to diverge. Therefore, the estimated steering angle is not updated. As a result, the steering angle can be estimated with high accuracy.
Further, the vehicle control device 17 does not update the estimated steering angle because the accuracy of the steering angle estimation deteriorates when the vehicle is at the grip limit. As a result, the steering angle can be estimated with high accuracy.
Furthermore, when the rate of change of the estimated steering angle is greater than a preset value (rate of change due to normal steering), the vehicle control device 17 changes the rear wheel speed due to a factor other than steering (such as slip). Therefore, the estimated steering angle is not updated. As a result, the steering angle can be estimated with high accuracy.

The vehicle control device 17 can perform feedforward control or the like by using the estimated steering angle information obtained by the determination process of the estimated steering angle update determination unit 48, and the driving force distribution control unit 18 can adjust the engine torque. The corresponding driving force distribution amount can be determined, and the four-wheel drive performance can be improved.
Further, the vehicle control device 17 can perform ON / OFF control of the idle stop control by the engine control device 25 by using the estimated steering angle information, and can improve the idle stop performance. The road surface reaction force control can be improved by the steering device, and the steering assist performance of the steering wheel 40 by the motor 41 can be improved.
Further, by using the estimated steering angle information, the vehicle control device 17 performs control such as a skid prevention device, a vehicle motion coordination control unit 20, a cornering lamp system control, and the like that cannot be controlled without the steering angle information. It becomes possible to do.

6 to 13 show Embodiment 2 of the present invention. In the second embodiment, the vehicle is configured in the same manner as the configuration of the vehicle 1 shown in FIG. 4 described above, and detailed description thereof will be omitted with reference to the reference numerals in FIG. In addition, the vehicle control device will not be described in detail with reference to the reference numerals in FIG. 5 for parts that are configured similarly to the configuration of the vehicle control device 17 shown in FIG. A description will be given with reference to FIG.
As shown in FIG. 4, the vehicle 1 uses the torque distribution clutch 11 to drive the driving force from the engine 2 according to the traveling state, and the front left wheel 7, the front right wheel 8, the rear left wheel 15, and the rear right wheel 16. The front left wheel 7 and the front right wheel 8 are driven as main drive wheels, and the rear left wheel 15 and the rear right wheel 16 are driven as auxiliary drive wheels.
As shown in FIG. 5, the torque distribution clutch 11 is connected to a vehicle control device 17. The vehicle control device 17 is based on various information input from the drive selection switch 24, the engine control device 25, the transmission control device 26, the antilock brake control device 27, the electric power steering control device 28, and the combination meter 29. The fastening force of the torque distribution clutch 11 is controlled so that the drive force distribution amount determined by the distribution control means 18 is obtained, and the engine is transferred to the front left wheel 7, the front right wheel 8, the rear left wheel 15 and the rear right wheel 16. The driving force of 2 is distributed according to the running state.
Further, the vehicle control device 17 controls the driving force / brake of the motor 41 that assists the steering by the vehicle motion cooperative control means 20 and the fastening force of the engine output / torque distribution clutch 11 in a coordinated manner to stabilize the traveling of the vehicle 1. Let Further, the vehicle control device 17 outputs the drive mode information to the engine control device 25 by the CAN communication function means 21, and outputs the ignition request information of the four-wheel drive indicator light / lock display warning light to the combination meter 29 for driving. Processing is performed by the system protection control means 19, fail-safe control means 22, and self-diagnosis means 23.

As shown in FIG. 13, the vehicle control device 17 includes estimated steering angle calculation means 43 that estimates the steering angle from the wheel speed without using the steering angle detection means. As shown in FIG. 7, the estimated steering angle calculation means 43 includes a front left wheel speed detection means 36 that detects the front left wheel speed of the front left wheel 7 and a front right wheel speed that detects the front right wheel speed of the front right wheel 8. Wheel speed detecting means 37, rear left wheel speed detecting means 38 for detecting the rear left wheel speed of the rear left wheel 15, and rear right wheel speed for detecting the rear right wheel speed of the rear right wheel 16. Detection means 39.
The estimated steering angle calculation means 43 includes a front left / right wheel difference calculation means 44, a rear left / right wheel difference calculation means 45, a vehicle speed calculation means 46, an estimated steering angle calculation means 47, and an estimated steering angle update determination means 48. I have.
The front left / right wheel difference calculating means 44 rotates the front left / right wheels based on the front left wheel speed detected by the front left wheel speed detecting means 36 and the front right wheel speed detected by the front right wheel speed detecting means 37. Calculate the difference. The rear left and right wheel difference calculating means 45 includes a rear left wheel speed detected by the rear left wheel speed detecting means 38 and a rear right wheel speed detected by the rear right wheel speed detecting means 39. From the above, the rear left and right wheel rotation difference is calculated.
The vehicle speed calculation means 46 calculates the rear side from the rear left wheel speed detected by the rear left wheel speed detection means 38 and the rear right wheel speed detected by the rear right wheel speed detection means 39. The vehicle speed of the wheels 15 and 16 is calculated. The estimated steering angle calculator 47 is based on the rear left and right wheel rotation difference calculated by the rear left and right wheel difference calculator 45 and the vehicle speed calculated by the vehicle speed calculator 46.
-Estimated steering angle = Rear left / right wheel rotation difference / (Conversion coefficient * Vehicle speed)
The estimated steering angle is calculated from the following formula. Note that the conversion coefficient in the equation is a constant value determined by the vehicle 1.
The estimated steering angle update determination means 48 determines whether or not to update the estimated steering angle calculated by the estimated steering angle calculation means 47.
The estimated steering angle update determination means 48 includes extremely low speed determination means 49 for determining whether or not the vehicle 1 is in an extremely low speed traveling state. The estimated steering angle update determining means 48 does not update the estimated steering angle when the extremely low speed determining means 49 determines that the vehicle 1 is in an extremely low speed traveling state.
The estimated steering angle update determining means 48 includes a grip limit determining means 50 for determining whether or not the vehicle 1 is at the grip limit. The estimated steering angle update determining unit 48 does not update the estimated steering angle when the grip limit determining unit 50 determines that the vehicle 1 is at the grip limit.
Further, the estimated steering angle update determining means 48 does not update the estimated steering angle when the rate of change of the estimated steering angle calculated by the estimated steering angle calculating means 47 is larger than a preset value.

The electric power steering control device 28 includes a resolver 42 that detects a rotation angle of a motor 41 that assists steering of the steering wheel 40. The electric power steering control device 28 outputs a resolver signal corresponding to the rotation angle of the motor 41 corresponding to the electrical angle of the resolver 42 as shown in FIG. As shown in FIG. 13, the vehicle control device 17 includes an offset amount calculation means 51, a midpoint learning means 52, and a resolver signal steering angle calculation means 53 in addition to the estimated steering angle calculation means 43. Yes.
The offset amount calculation means 51 calculates the difference between the rotation angle detected by the resolver 42 and the estimated steering angle calculated by the estimated steering angle calculation means 43 as an offset amount. The midpoint learning unit 52 calculates a correction amount based on the offset amount calculated by the offset amount calculation unit 51. The resolver signal rudder angle calculating means 53 calculates a steering angle from the rotation angle detected by the resolver 42 and the correction amount calculated by the midpoint learning means 52.
The midpoint learning unit 52 does not use the offset amount calculated by the offset amount calculation unit 51 when the estimated steering angle update determination unit 48 determines not to update the estimated steering angle for calculating the correction amount. The midpoint learning means 52 does not use the offset amount calculated by the offset amount calculation means 51 when calculating the correction amount when the rate of change of the rotation angle detected by the resolver 42 is larger than a preset value. The midpoint learning means 52 calculates the correction amount by calculating the offset amount calculated by the offset amount calculation means 51 when the rate of change of the steering angle calculated by the resolver signal steering angle calculation means 53 is larger than a preset value. Not used for.
Further, the midpoint learning means 52 has a difference between the rate of change of the rotation angle detected by the resolver 42 and the rate of change of the estimated steering angle calculated by the estimated steering angle calculation means 43 larger than a preset value. Sometimes the offset amount calculated by the offset amount calculation means 51 is not used for calculating the correction amount. The midpoint learning means 52 is a value in which a difference between the change rate of the steering angle calculated by the resolver signal steering angle calculation means 53 and the change rate of the estimated steering angle calculated by the estimated steering angle calculation means 43 is set in advance. The offset amount calculated by the offset amount calculation means 51 when it is larger than the offset amount is not used for the correction amount calculation.

Next, the operation will be described.
The vehicle control device 17 calculates the front left and right wheel rotation difference by the front left and right wheel difference calculation means 44, calculates the rear left and right wheel rotation difference by the rear left and right wheel difference calculation means 45, and calculates the vehicle speed by the vehicle speed calculation means 47. The estimated steering angle is calculated by the estimated steering angle calculating means 47, and the estimated steering angle update determining means 48 performs the estimated steering angle update determining process.
As shown in FIG. 8, when the estimated steering angle update determination unit 48 starts the estimated steering angle update determination process (A01), the vehicle control device 17 determines an extremely low speed (A02), and estimates the estimated steering angle reliability. (A03), the grip limit is determined (A04), and it is determined whether the estimated steering angle update condition is satisfied (A05).
In the extremely low speed determination (A02), it is determined whether or not the vehicle speed is equal to or lower than a threshold value (when the vehicle speed is equal to or lower than the threshold value, it is determined as an extremely low speed traveling state). In the determination of the estimated steering angle reliability (A03), it is determined whether or not the rate of change of the estimated steering angle is equal to or greater than a threshold value (when it is equal to or greater than the threshold value, it is determined that there is no reliability). In the determination of the grip limit (A04), it is determined whether or not the difference between the front left / right wheel rotation difference and the rear left / right wheel rotation difference is equal to or greater than a threshold value (when it is equal to or greater than the threshold value, the grip limit is determined).
In the determination of the estimated steering angle update condition (A05), as shown in FIG. 9, it is determined whether all the conditions of extremely low speed determination, estimated steering angle reliability determination, and grip limit determination are satisfied. (If the speed is not extremely low, the estimated steering angle is not distrusted, and the grip limit is not met, the condition is met)
If the determination (A05) is YES, the estimated steering angle is updated (A06), and the estimated steering angle update determination process is terminated (A07). If the determination (A05) is NO, the previous value is held without updating the estimated steering angle (A08), and the estimated steering angle update determination process is terminated (A07).

The vehicle control device 17 calculates the difference between the rotation angle detected by the resolver 42 and the estimated steering angle calculated by the estimated steering angle calculating means 43 following the calculation of the estimated steering angle by the estimated steering angle calculating means 43. Is calculated as an offset amount by the offset amount calculation means 51, and based on the offset amount calculated by the offset amount calculation means 51, the midpoint learning means 52 calculates a correction amount as follows.
As shown in FIG. 10, when the midpoint learning process by the midpoint learning means 52 starts (B01), the vehicle control device 17 determines the extremely low speed (A02) in FIG. 8 and determines the estimated steering angle reliability. (A03) In addition to the grip limit determination (A04), the resolver signal rudder angle reliability is determined (B02), and it is determined whether the midpoint learning condition is satisfied (B03).
The determination of the resolver signal steering angle reliability (B03) determines whether or not the difference between the change rate of the resolver signal steering angle and the change rate of the estimated steering angle is equal to or less than a threshold value.
In the determination of the midpoint learning condition (B03), as shown in FIG. 11, all conditions of extremely low speed determination, estimated steering angle reliability determination, grip limit determination, and resolver signal steering angle reliability determination are satisfied. Determine whether. (The condition is met if the speed is not extremely low, the estimated steering angle is not distrusted, the grip limit is not reached, and the resolver signal rudder angle is not distrusted)
If the determination (B03) is NO, the midpoint learning process is terminated without calculating the correction amount (B08). If the determination (B03) is YES, the offset amount calculated from the difference between the resolver signal (rotation angle) and the estimated steering angle is integrated (B04), and it is determined whether the offset amount is integrated a predetermined number of times (B05). .
If this determination (B05) is NO, the midpoint learning process is terminated without calculating the correction amount (B08). If this determination (B05) is YES, the offset amount is averaged (B06), the correction amount is calculated by filtering from the average value of the offset amount, and the correction amount is updated with this calculated correction amount (B07). The midpoint learning process is terminated (B08).
The resolver signal rudder angle calculation means 53 calculates the steering angle from the correction amount calculated by the midpoint learning means 52 and the rotation angle detected by the resolver 42 and outputs it to the next stage.
The midpoint learning means 52 for calculating the correction amount sets in advance the rate of change of the rotation angle detected by the resolver 42 when the estimated steering angle update determining means 48 determines that the estimated steering angle is not updated. The offset amount calculated by the offset amount calculation unit 51 is corrected when the value is larger than the calculated value or when the change rate of the steering angle calculated by the resolver signal steering angle calculation unit 53 is larger than a preset value. Not used for quantity calculation.
Further, the midpoint learning means 52 is used when the difference between the change rate of the rotation angle detected by the resolver 42 and the change rate of the estimated steering angle calculated by the estimated steering angle calculation means 43 is larger than a preset value. Alternatively, when the difference between the rate of change of the steering angle calculated by the resolver signal rudder angle calculating unit 53 and the rate of change of the estimated steering angle calculated by the estimated steering angle calculating unit 43 is larger than a preset value, The offset amount calculated by the offset amount calculation means 51 is not used for correction amount calculation.

As described above, the vehicle control device 17 steers using the rotation angle detected by the resolver 42 that detects the rotation angle of the motor 41 that assists steering and the estimated steering angle calculated by the estimated steering angle calculation means 43. Since the angle is calculated, the steering angle can be calculated even when the vehicle is stopped or slipping, and the steering angle can be calculated from the wheel speed and the resolver signal. Therefore, the vehicle control device 17 can calculate the steering angle and perform feed-forward control of the four-wheel drive control even in a vehicle not equipped with the steering angle detection means. Further, not only four-wheel drive control but all control that requires steering angle information can be executed.
Since the wheel speed detecting means 36 to 39 for detecting the wheel speed and the resolver 42 are mounted on many vehicles, the steering angle can be calculated without mounting new detecting means. Since the vehicle control device 17 calculates the steering angle from the wheel speed and the resolver signal, the vehicle control device 17 can calculate the correction amount and calculate the steering angle only with a simple arithmetic process.
When the estimated steering angle update determining means 48 determines that the estimated steering angle is not updated, the vehicle control device 17 does not use the offset amount calculated by the offset amount calculating means 51 for calculating the correction amount. Therefore, the steering angle can be calculated from the rotation angle detected by the resolver 42 with high accuracy.
Further, the vehicle control device 17 is configured such that when the rate of change of the rotation angle detected by the resolver 42 is larger than a preset value, or the rate of change of the steering angle calculated by the resolver signal steering angle calculation means 53. Is larger than a preset value, the offset amount calculated by the offset amount calculation means 51 is not used for calculating the correction amount, so that the steering angle can be accurately calculated from the rotation angle detected by the resolver 42. .
Further, in this vehicle control device 17, the difference between the change rate of the rotation angle detected by the resolver 42 and the change rate of the estimated steering angle calculated by the estimated steering angle calculation means 43 is larger than a preset value. Or when the difference between the change rate of the steering angle calculated by the resolver signal steering angle calculation means 53 and the change rate of the estimated steering angle calculated by the estimated steering angle calculation means 43 is larger than a preset value. Since the offset amount calculated by the offset amount calculation means 51 is not used for calculating the correction amount, the steering angle can be accurately calculated from the rotation angle detected by the resolver 42.

The vehicle control device 17 can perform feedforward control and the like by using the steering angle information calculated from the rotation angle detected by the resolver 42 and the estimated steering angle calculated by the estimated steering angle calculation means 43. The driving force distribution control means 18 can determine the driving force distribution amount according to the engine torque, and can improve the four-wheel driving performance.
In addition, the vehicle control device 17 can perform ON / OFF control of idle stop control by the engine control device 25 by using the steering angle information, and can improve idle stop performance. The road surface reaction force control can be improved by the apparatus, and the steering assist performance of the steering wheel 40 by the motor 41 can be improved.
Further, the vehicle control device 17 uses the steering angle information to control the skid prevention device, the vehicle motion coordination control unit 20, the cornering lamp system control, and the like that cannot be controlled without the steering angle information. It becomes possible.

As shown in FIG. 13, the vehicle control device 17 applies the driving force from the engine 2 to the front left wheel 7, the front right wheel 8, and the auxiliary driving wheel that are main driving wheels according to the traveling state of the vehicle. A torque distribution clutch 11 serving as a driving force distribution means for distributing to a certain rear left wheel 15 and rear right wheel 16 is provided, and a torque distribution clutch based on the steering angle calculated by the resolver signal steering angle calculation means 53 is provided. The driving force distribution control means 18 for determining the driving force distribution amount of 11 is provided.
As a result, the vehicle control means 17 can calculate the steering angle and determine the driving force distribution amount according to the engine torque in the driving force distribution control means 18 even for a vehicle not equipped with a steering angle sensor. The fastening force of the torque distribution clutch 11 can be controlled so that the determined driving force distribution amount is obtained.
As a result, the vehicle control device 17 suppresses the occurrence of the tight corner braking phenomenon of the vehicle 1 and reduces the turning performance, the generation of noise / vibration and the overload on the drive system due to the tight corner braking phenomenon. Can be prevented.

In the second embodiment, as shown in FIGS. 10 and 11, as the midpoint learning condition, extremely low speed determination, estimated steering angle reliability determination, grip limit determination, and resolver signal steering angle reliability determination are set, The correction amount is calculated when all these conditions are satisfied, but the present invention is not limited to this.
14 to 15 show a first modification of the midpoint learning process. The vehicle control device 17 includes a straight traveling determination unit 54 that determines whether or not the vehicle 1 is in a straight traveling state (see FIG. 13). The straight traveling determination unit 54 determines the straight traveling state of the vehicle from the estimated steering angle calculated by the estimated steering angle calculating unit 43, and determines the turning traveling state of the vehicle from the wheel speed detected by the wheel speed detecting units 36 to 39. The midpoint learning unit 52 does not use the offset amount calculated by the offset amount calculation unit 51 when the straight traveling determination unit 54 determines that the vehicle 1 is not in the straight traveling state for calculating the correction amount.
As shown in FIG. 15, when the midpoint learning process by the midpoint learning means 52 is started (C01), the vehicle controller 17 determines the extremely low speed (A02) in FIG. 8 and determines the estimated steering angle reliability. (A03), in addition to the grip limit determination (A04), the straight-ahead state is determined (C02), the turning state is determined (C03), the resolver signal steering angle reliability is determined (C04), It is determined whether the point learning condition is satisfied (C05).
In the determination of the midpoint learning condition (C05), as shown in FIG. 15, all conditions of extremely low speed determination, estimated steering angle reliability determination, grip limit determination, straight traveling state determination, and resolver signal steering angle reliability determination are included. It is determined whether or not (If the speed is not extremely low, the estimated steering angle is not distrusted, the grip limit is not reached, the vehicle is not turning (straight running state), and the resolver signal rudder angle is not distrusted)
When this determination (C05) is NO, the midpoint learning process is terminated without calculating the correction amount (C10). If this determination (C05) is YES, the offset amount calculated from the difference between the resolver signal (rotation angle) and the estimated steering angle is integrated (C06), and it is determined whether the offset amount is integrated a predetermined number of times (C07). .
If this determination (C07) is NO, the midpoint learning process is terminated without calculating the correction amount (C10). If this determination (C07) is YES, the offset amount is averaged (C08), the correction amount is calculated by filtering from the average value of the offset amount, and the correction amount is updated with the calculated correction amount (C09). The midpoint learning process is terminated (C10).
The resolver signal rudder angle calculation means 53 calculates the steering angle from the correction amount calculated by the midpoint learning means 52 and the rotation angle detected by the resolver 42 and outputs it to the next stage.
As described above, the vehicle control device 17 does not use the offset amount calculated by the offset amount calculating unit 51 for calculating the correction amount when the straight traveling determining unit 54 determines that the vehicle 1 is not in the straight traveling state. The steering angle can be calculated with high accuracy from the rotation angle detected by 42.

  The present invention can estimate a steering angle even in a vehicle not equipped with a steering angle detection means, and can be applied to all vehicle control devices that require steering angle information.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Engine 3 Transmission 4 Front differential 7 Front left wheel 8 Front right wheel 9 Transfer 10 Propeller shaft 11 Torque distribution clutch 12 Rear differential 15 Rear left wheel 16 Rear right wheel 17 Vehicle control device 18 Driving force distribution control Means 25 Engine control device 26 Transmission control device 27 Anti-lock brake control device 28 Electric power steering control device 36 Front left wheel speed detection means 37 Front right wheel speed detection means 38 Rear left wheel speed detection means 39 Rear right wheel speed detection Means 41 Motor 42 Resolver 43 Estimated steering angle calculating means 44 Front left / right wheel difference calculating means 45 Rear left / right wheel difference calculating means 46 Vehicle speed calculating means 47 Estimated steering angle calculating means 48 Estimated steering angle update determining means

Claims (12)

  Left wheel speed detecting means for detecting the left wheel speed of the vehicle, right wheel speed detecting means for detecting the right wheel speed of the vehicle, left wheel speed detected by the left wheel speed detecting means and the right wheel speed detecting means Left and right wheel difference calculating means for calculating the left and right wheel rotation difference from the right wheel speed detected by the left wheel speed, the left wheel speed detected by the left wheel speed detecting means and the right wheel speed detected by the right wheel speed detecting means. Vehicle speed calculating means for calculating the vehicle speed from the above, estimated steering angle calculating means for calculating the estimated steering angle based on the left and right wheel rotation difference calculated by the left and right wheel difference calculating means and the vehicle speed calculated by the vehicle speed calculating means And an estimated steering angle calculating means comprising: an estimated steering angle update determining means for determining whether or not to update the estimated steering angle calculated by the estimated steering angle calculating means.   An extremely low speed determining means for determining whether or not the vehicle is in an extremely low speed traveling state is provided, and the estimated steering angle update determining means is estimated steering when the extremely low speed determining means determines that the vehicle is in an extremely low speed traveling state. The vehicle control device according to claim 1, wherein the corner is not updated.   Grip limit determination means for determining whether or not the vehicle is at the grip limit, and the estimated steering angle update determination means does not update the estimated steering angle when the grip limit determination means determines that the vehicle is at the grip limit. The vehicle control device according to claim 1, characterized in that:   The estimated steering angle update determining means does not update the estimated steering angle when the rate of change of the estimated steering angle calculated by the estimated steering angle calculating means is larger than a preset value. The vehicle control device described.   A resolver that detects a rotation angle of a motor that assists steering; an offset amount calculation unit that calculates a difference between the rotation angle detected by the resolver and the estimated steering angle calculated by the estimated steering angle calculation unit as an offset amount; A steering angle based on the midpoint learning means for calculating the correction amount based on the offset amount calculated by the offset amount calculation means, the rotation angle detected by the resolver, and the correction amount calculated by the midpoint learning means The vehicle control device according to claim 1, further comprising a resolver signal rudder angle calculation unit that calculates   The midpoint learning means does not use the offset amount calculated by the offset amount calculating means when calculating that the estimated steering angle is not updated by the estimated steering angle update determining means for calculating the correction amount. The vehicle control device according to claim 5.   The midpoint learning means does not use the offset amount calculated by the offset amount calculation means for the correction amount calculation when the rate of change of the rotation angle detected by the resolver is larger than a preset value. The vehicle control device according to claim 5, which is fine.   The midpoint learning means calculates the offset amount calculated by the offset amount calculation means when the rate of change of the steering angle calculated by the resolver signal steering angle calculation means is greater than a preset value. The vehicle control device according to claim 5, which is not used.   The midpoint learning means is configured to detect the offset when a difference between the change rate of the rotation angle detected by the resolver and the change rate of the estimated steering angle calculated by the estimated steering angle calculation means is larger than a preset value. 6. The vehicle control device according to claim 5, wherein the offset amount calculated by the amount calculation means is not used for correction amount calculation.   The midpoint learning means has a difference between a change rate of the steering angle calculated by the resolver signal steering angle calculation means and a change rate of the estimated steering angle calculated by the estimated steering angle calculation means based on a preset value. 6. The vehicle control device according to claim 5, wherein the offset amount calculated by the offset amount calculation means is not used for correction amount calculation when the offset amount is larger.   The vehicle includes a straight traveling determination unit that determines whether or not the vehicle is in a straight traveling state, and the midpoint learning unit calculates an offset amount calculated by the offset amount calculation unit when the straight traveling determination unit determines that the vehicle is not in a straight traveling state. Is not used for correction amount calculation. The vehicle control device according to claim 5.   Driving force distribution means for distributing the driving force from the engine to main driving wheels and sub driving wheels according to the running state of the vehicle, and driving force distribution based on the steering angle calculated by the resolver signal steering angle calculation means The vehicle control device according to any one of claims 5 to 11, further comprising driving force distribution control means for determining the amount.

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