JPH0826127A - Method for controlling automatic steering device - Google Patents

Abstract

PURPOSE:To correctly set the threshold to judge the steering will of a driver and the zero point in starting the system to start the control of an automatic steering device. CONSTITUTION:A gear ratio variable mechanism 25 provided with a steering control motor 36 and a torque control motor 38 is provided on a steering device 10 of a vehicle, and the steering is achieved by the steering wheel operation by a driver. The tire side is automatically steered by controlling the rotation of the steering control motor 36 by the image data at the forward part of the vehicle, and the torque on the steering wheel side is controlled by the torque control motor 38. When the system is started, a judgement is made whether the driver takes the steering wheel 9 or not, and when the driver takes his hands off the steering wheel, an input shaft 21 on the steering wheel side is rotated by the torque control motor 38, while when the driver takes the steering wheel, an output shaft 22 on the tire side is rotated by the steering control motor 38 to achieve the zero point setting so as to align the position of the output shafts 21, 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an automatic steering device which is used in a driving assistance system (ADA) of a vehicle such as an automobile and automatically electronically steers the vehicle. The present invention relates to a method of setting a threshold value for determining the origin when starting the system and the driver's steering intention.

[0002]

2. Description of the Related Art In recent years, as a measure to drastically improve the safety of a vehicle, a technique for avoiding a collision against a collision damage reducing technique such as an airbag, that is, a driving operation system is actively assisted for safety. A comprehensive driving support system (ADA, Active Drive Assist system) that automatically controls the side has been developed. This ADA system has cameras mounted in front of and behind the vehicle to recognize a road condition, another vehicle, and an external environment such as an obstacle three-dimensionally by a control unit.
The driver is provided with the same autonomous running capability as the driver, and the autonomous running capability is configured to automatically and properly operate various devices in the operation system such as the brake, throttle, and steering. Then, as functions aimed at by the ADA system, a collision prevention function and a limited automatic traveling function are considered. The collision prevention function is to correct the steering wheel or avoid an obstacle by automatic steering. The limited automatic travel function is to maintain a safe inter-vehicle distance from the preceding vehicle while automatically steering instead of the driver to prevent deviation from the lane.

The above-mentioned ADA system will be described more specifically. For example, Japanese Patent Application Laid-Open No. 4-653 by the present applicant.
As shown in the application No. 47, the front scene and traffic environment are captured by a plurality of cameras mounted on the vehicle, the image is divided into small areas, and the distance is calculated by triangulation for each, and the entire screen is cubic. Obtain an image of the original distance distribution. Then, lanes, vehicles in front, obstacles, etc. are separated and detected from the distance image. Left and right white lines, road shapes, etc. are recognized from the lane. For a forward vehicle or an obstacle, what kind of object the object is, the relative distance to the obstacle, the speed, and the like are recognized to obtain various image data.

As a system for automatically steering using the above-mentioned image data, as shown in Japanese Patent Laid-Open No. 4-356273, a planetary gear type gear having a steering control motor and a torque control motor in a steering system of a steering device. A ratio variable mechanism is provided. Then, one or both of the steering control motor and the torque control motor are controlled, and the gear ratio variable mechanism is operated to enable manual steering and automatic steering. Further, in the automatic steering mode, it is possible to assist the driver in various forms by controlling the two motors.

Therefore, in the future, it is required to concretely determine the driving support for the driver and establish a control method therefor. Therefore, as a way of driving assistance, the driver's intention to steer and let go can be judged by torque sensor signals, etc., and other than let go, the driver can prioritize manual steering and automatically operate it to oppose the driver's will. Avoid things. In this case, since the arm strength during steering wheel operation is relatively large depending on the driver's age, gender, etc., the threshold value for determining the driver's intention to let the driver steer and release is set when starting the system to start controlling the automatic steering device. It is desired to do. In addition, when the system is started, it is necessary to align the positions of the input shaft on the handle side and the output shaft on the tire side in the rotational direction, and in this case, the torque control motor on the handle side and the steering control motor on the tire side are used separately. It is desired to reduce the load on the motor side and control quickly.

Conventionally, as for the control of the above-mentioned automatic steering device, there is, for example, the prior art of Japanese Patent Laid-Open No. 4-300781. In this prior art, the outside world is recognized by the outside world recognition means, the traveling system road is recognized based on the image data of the recognition result, the deviation amount of the vehicle position with respect to the traveling system road is calculated, and the deviation amount and the steering operation state are calculated. It is shown that the steering of the vehicle is controlled by controlling the automatic steering actuator based on the above.

[0007]

By the way, in the above prior art, the vehicle is always automatically steered by the amount of deviation between the traveling system road and the attitude of the host vehicle based on the image data, and the driver is operated. This is a control method for mechanically correcting the deficiency in the steering wheel operation. Therefore, when the driver has the intention to operate the steering wheel, it is not possible to perform steering control by manual steering while respecting the intention. Further, it cannot be applied to the control for determining the origin or steering intention of the driver.

SUMMARY OF THE INVENTION In view of the above points, an object of the present invention is to accurately set the threshold value for determining the origin when starting the system for starting the control of the automatic steering device and the driver's steering intention.

[0009]

In order to achieve this object, the present invention provides a steering system for a vehicle with a gear ratio variable mechanism including a steering control motor and a torque control motor for steering by a driver's steering wheel operation. In the automatic steering device that controls the rotation of the steering control motor based on the image data in front of the vehicle to automatically steer the tire side and the torque of the steering wheel is controlled by the torque control motor, the driver starts when the system starts to control the automatic steering device. It is judged whether the steering wheel is held or not.If the steering wheel is released, the steering wheel input shaft is rotated by the torque control motor.If the steering wheel is held, the tire output shaft is rotated by the steering control motor. The feature is that the origin is set.

[0010]

In the present invention based on the above control method, the origin is set so as to align the handle side input shaft and the tire side output shaft when the system starts to control the automatic steering device immediately after the engine is started. At this time, if the handle is free, the torque control motor rotates the handle-side input shaft, so that the origin can be quickly set without burdening the motor. When the driver is holding the steering wheel, the steering control motor rotates the output shaft on the tire side to find the origin. At this time, the steering wheel grip must be judged by the operation of the torque control motor and the signal from the steering torque sensor. Thus, it is possible to perform the operation chuck of the two motors.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. An outline of the ADA system will be described with reference to FIG. First, the throttle valve 3 of the engine 2 of the vehicle 1 is provided with an actuator 11 that opens and closes by an electric signal,
An automatic brake hydraulic unit 12 that increases or decreases the brake pressure by an electric signal is provided in a brake device 8 that applies brake pressure to the wheel cylinders 7 of the front wheels 5 and the rear wheels 6 by operating the brake pedal 4 to perform braking. A CCD camera 13 for picking up a predetermined range in front of the vehicle 1 is arranged on the left and right sides of the vehicle 1, and an automatic steering power unit 1 for steering an electric signal to a steering device 10 having a steering wheel 9 is provided.
4 are provided.

As a control system, the image recognition control unit 15 to which the image pickup signal of the CCD camera 13 is input is provided, and the distance is calculated by the triangulation method based on the image pickup signal, and an image having a three-dimensional distance distribution is displayed on the entire screen. obtain. Then, lanes, vehicles in front, obstacles, etc. are separately detected from the distance image, and left and right white lines, road shapes, etc. are recognized from the lanes. For a forward vehicle or an obstacle, what kind of object the object is, the relative distance to the obstacle, the speed, and the like are recognized to obtain various image data. This image data is input to the inter-vehicle distance control unit 16 and the automatic steering control unit 17.

The inter-vehicle distance control unit 16 calculates the acceleration / deceleration so as to maintain a safe distance with respect to the preceding vehicle and obstacles on the road based on the image data and various other sensor signals, and an appropriate acceleration / deceleration based on this acceleration / deceleration is calculated. A throttle signal indicating the throttle opening is output to the actuator 11 for throttle control. Further, a brake signal having an appropriate brake pressure based on the acceleration / deceleration is output to the automatic brake hydraulic unit 12 for brake control. Even if the driver's brake operation is insufficient, the vehicle can be safely driven by maintaining a safe vehicle distance and preventing a collision. The automatic steering control unit 17 calculates the deviation between the white line on the road and the vehicle based on the image data and various other sensor signals, and outputs a steering signal based on this deviation to the automatic steering power unit 14 to perform steering control. And even when the driver's handle is released,
It is configured so that it can safely follow lanes.

In FIG. 3, the automatic steering power unit 14
The configuration of will be described. First, the steering device 10
The steering shaft 20 is divided into an input shaft 21 and an output shaft 22, a handle 9 is provided at the end of the input shaft 21, and the output shaft 22 is connected to the front wheels 5 via a hydraulic power steering mechanism 23. The variable gear ratio mechanism 25 is connected between 21 and 22 by bypass. Gear ratio variable mechanism 25
Is constituted by combining two sets of gears 26 and 27 and one set of planetary gear 30 with the input and output shafts 21 and 22 and the motor shaft 24 arranged in parallel therewith.

That is, in the first gear 26, a small-diameter drive gear 26a is integrally connected to the input shaft 21, and a large-diameter driven gear 26b is rotatably provided on the motor shaft 24. In the second gear 27, the large-diameter drive gear 27a is the motor shaft 2
4, the driven gear 27b having a small diameter is integrally coupled to the output shaft 22. In the planetary gear 30, the sun gear 31 is integrally coupled to the motor shaft 24, the ring gear 32 is formed inside the drive gear 27 a of the second gear 27, and the pinion 33 that meshes with the sun gear 31 and the ring gear 32 is the driven gear of the first gear 26. It is supported by a carrier 34 integral with 26b. A steering control motor 36 is connected to one end of the motor shaft 24 via a reversibly rotatable worm gear 35, and a torque control motor 38 is connected to the input shaft 21 via a similar worm gear 37. Further, between the input shaft 21 and the output shaft 22, there is provided a stopper 39 which is directly connected when the tire collides with a curb or the like and a large steering torque is input and both shafts 21 and 22 rotate by a predetermined angle or more.

When the driver steers the steering wheel 9 with the sun gear 31 of the motor shaft 24 fixed, the carrier 34 of the planetary gear 30 is rotated by the input shaft 21 and the first gear 26, and the pinion 33 is planet-rotated. The ring gear 32 and the second gear 27 rotate the output shaft 22 in the same direction as the steering wheel 9 to steer the output shaft 22. In this case, the rotations of the input and output shafts 22 are made substantially the same by selecting the number of gear teeth. Further, in a state where the torque control motor 38 fixes the input shaft 21 to perform torque assist so as to cancel the steering reaction force, the steering control motor 36 causes the sun gear 3 to rotate.
When 1 is rotated, the ring gear 32 is rotated by the rotation of the pinion 33.
And the output shaft 22 is rotated in the same direction via the second gear 27 and electrically steered.

As a control system, the input shaft 21 has a steering angle sensor 4 for detecting the steering angle Qh of the steering wheel and its angular velocity ωh.
0, a steering torque sensor 41 for detecting the steering torque Th is provided, and a steering angle sensor 42 for detecting the tire steering angle Qp and its angular velocity ωp is provided on the output shaft 22. Further, the motor shaft 24 of the gear ratio variable mechanism 25 is provided with a phase angle sensor 43 for detecting the phase angle Qs. The image data of the image recognition control unit 15, the vehicle speed V of the vehicle speed sensor 44, and the signals of the sensors 40 to 43 are input to the automatic steering control unit 17 and electrically processed, whereby the steering control motor 36 and the torque control are performed. It is configured to control the motor 38.

In FIG. 1, the automatic steering control unit 17
Will be described. First, it has an origin search control unit 50 and a threshold value setting unit 51 that are activated when the system starts to control the automatic steering device immediately after the engine is started. The origin search control unit 50 rotates the input shaft 21 on the steering wheel side by the torque control motor 38 or rotates the output shaft 22 on the tire side by the steering control motor 36 to generate the steering wheel steering angle Qh.
And the shafts 21 and 22 so that the tire steering angle Qp and the tire steering angle Qp coincide with each other.
Align. The threshold value setting unit 51 temporarily fixes the steering wheel 9 by the torque control motor 38 at a safe extremely low speed, and checks the magnitude of the arm force at the time of operating the steering wheel of each driver by the signal of the steering torque sensor 41 at this time. . Then, based on the driver's arm strength, a threshold value a for determining the driver's intention to steer and release is set.

The threshold value a, the steering torque Th, and the vehicle speed V are input to the mode determining unit 52, and the threshold value a is compared with the steering torque Th when the driver actually operates the steering wheel while the vehicle is traveling, and the driver's steering intention is compared. If it is judged, the manual steering mode is selected, and if it is released, the automatic steering mode is selected. Further, the steering wheel angle Qh, the tire turning angle Qp, the vehicle speed V, and the image data signals are input to the steering control unit 53, and the motor is controlled according to each mode after the origin search is completed.

That is, in the manual steering mode, a predetermined current is supplied to the steering control motor 36 to change the gear ratio variable mechanism 2.
The sun gear 31 of No. 5 is fixed. In the automatic steering mode, the torque control motor 38 applies an assist torque that cancels the steering reaction force acting on the steering wheel 9 side. Then, a target steering angle for avoiding a collision or a lane departure is obtained from the target value based on the image data and the actual steering angle of the vehicle, and a current according to the target steering angle is supplied to the steering control motor 36. .

Next, the operation of this embodiment will be described. First, the origin search control will be described with reference to the flowchart of FIG. 4. Immediately after the engine is started, the system power is checked in step S1, and if it is turned off, the process proceeds to step S2 to end the steering control. On the other hand, when the power of the system is turned on and the system starts to control the automatic steering device, the process proceeds to step S3 to prepare the origin search operation, and in step S4, first, the torque control motor 38 rotates the input shaft 21 on the steering wheel side. . At this time, if the driver holds the steering wheel 9, the steering torque sensor 41
Is output, and the sensor signal is not output when the driver releases it, which allows the driver to determine whether or not the driver is holding the steering wheel.

Therefore, in step S5, the steering torque sensor 4
It is checked whether the signal No. 1 has been output for a certain period of time. If the sensor signal is not output, the process proceeds to step S6.
If the home search is not completed, return. And step S4
The rotation of the input shaft 21 by the torque control motor 38 adjusts the steering wheel steering angle Qh to the tire steering angle Qp to find the origin. When the home search is completed, the process proceeds from step S6 to step S7, and the steering control initialization is completed.
In this way, when the handle is released, the torque control motor 3
8 allows the origin to be set quickly without imposing an extra load on the motor.

When it is determined that the driver holds the steering wheel 9 by outputting the sensor signal, the process proceeds from step S5 to step S8 to stop the origin search by the torque control motor 38, and the steering control motor 36 is operated in step S9. The output shaft 22 is rotated to steer the tire. Then, the origin of the origin is adjusted according to the steering angle Qp of the steering wheel Qh, and when the origin is completed, the process proceeds from step S10 to step S7. Therefore, in this case, since the tire is steered, a load is applied to the motor, and the steering reaction force of the steering control motor 36 is dispersed to the steering wheel side and becomes slow, but the operation check of the two motors 36 and 38 can be performed. .

The threshold value setting control will be described with reference to the flow chart of FIG. 5. When the system is started, the process proceeds from step S1 to step S20, and when there is no obstacle ahead and the vehicle speed is, for example, 5 km / h or less, a safe running state is determined. ,
In step S21, the input shaft 21 is fixed by the torque control motor 38. Therefore, when the driver grips the steering wheel 9 to operate the arm force, the steering torque sensor 41
It becomes possible to detect it directly with.

Therefore, in step S22, it is checked whether the signal from the steering torque sensor 41 is output for a certain period of time. If the steering torque Th of the sensor signal is detected, step S2
3, the input shaft fixing by the torque control motor 38 is stopped. After that, the process proceeds to step S24 and the steering torque Th
Learns the magnitude of the driver's arm force, determines the threshold value a based on this, and proceeds to step S25 to complete the steering control initial setting. In this way, when the driver has different arm strengths depending on age and sex, a threshold value a for determining the driver's steering intention according to the arm strength is set for each driver.

Further, steering control will be described with reference to the flowchart of FIG. 6. When the system is started, the process proceeds from step S1 to step S30 to start the operation of the steering control motor 36, and in step S31, the steering reaction force is offset. The fixed control is started, and the operation of the torque control motor 38 is started in step S32. Then step S
At 33, the steering torque Th is compared with the threshold value a, and if Th ≧ a, it is determined whether the driver actually holds the steering wheel 9 or not. In this case, the process proceeds to step S34, the sun gear 31 is fixed by the steering control motor 36, the steering wheel fixing control by the torque control motor 38 is stopped at step S35, and the manual steering mode is switched at step S36.

When the driver operates the steering wheel, the input shaft 21 and the first and second gears 2 of the gear ratio variable mechanism 25 are operated.
6, 27, the output shaft 22 rotates in the same direction by the operation of the planetary gear 30 with respect to the fixed sun gear 31, and the front wheels 5 are freely steered left and right by the operation of the hydraulic power steering mechanism 23. When the driver's intention to steer is determined in this manner, the driver's intention is respected and steering is given priority to the driver's steering wheel operation.

On the other hand, if Th <a, it is judged that the driver has let go of the vehicle, and the process returns, and the two motors 36 and 38 in steps S30 to S32 actuate the automatic steering. Therefore, in the gear ratio variable mechanism 25, the worm gear 35, the motor shaft 24, and the sun gear 31 are rotated by the operation of the steering control motor 36, but since the ring gear 32 is heavily loaded on the tire side, the carrier 34 or the like reverses. The steering reaction force of the lever acts on the steering wheel 9 side. At this time, the torque control motor 38 and the worm gear 37 are actuated, and the input shaft 21,
Since the torque is assisted to fix the first gear 26, the carrier 34, etc., the rotation of the sun gear 31 by the steering control motor 36 resists the load on the tire side, and thus the ring gear 32, the second gear 27, and the output shaft. 22 rotates and front wheel 5
Is automatically steered. Therefore, even when the vehicle is released, steering control is performed safely so as to avoid a collision, a lane departure, or the like.

Although the embodiment of the present invention has been described above, the invention can be applied to the case where the structure of the gear ratio variable mechanism is different.

[0030]

As described above, according to the present invention,
When the system is started in the automatic steering device, it is determined whether the driver holds the steering wheel.If the driver releases the steering wheel, the torque control motor rotates the input shaft on the steering wheel side to turn the input and output axes to the origin. The burden can be reduced and the origin can be set quickly. When the steering wheel is gripped, the steering control motor rotates the tire side output shaft to find the origin. At this time, the steering wheel grip is judged by the operation of the torque control motor and the signal of the steering torque sensor. It is also possible to check the operation. Since the signals of the steering angle sensor and the steered angle sensor are used, the phase angle sensor becomes unnecessary. When the system starts to control the automatic steering device, the input shaft is further temporarily fixed by the torque control motor, and the arm force of each driver is checked by the signal of the steering torque sensor. Based on this arm force of the driver, the driver's steering intention is determined. Since the threshold value for determining is set, the threshold value can be accurately set when the driver's arm strength is different. Therefore, properly judge the driver's steering intention,
Driver priority driving support can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an automatic steering control unit suitable for a control method for an automatic steering device according to the present invention.

FIG. 2 is a configuration diagram showing an overall outline of an ADA system.

FIG. 3 is a configuration diagram showing an automatic steering power unit.

FIG. 4 is a flowchart showing a control of origin search.

FIG. 5 is a flowchart showing control of threshold setting.

FIG. 6 is a flowchart showing steering control.

[Explanation of symbols]

 1 vehicle 9 steering wheel 10 steering device 14 automatic steering power unit 15 image recognition control unit 17 automatic steering control unit 21 input shaft 22 output shaft 25 gear ratio variable mechanism 36 steering control motor 38 torque control motor 50 origin control unit 51 threshold setting unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B62D 117: 00 119: 00 137: 00

Claims (2)

[Claims] 1. A steering apparatus for a vehicle is provided with a gear ratio variable mechanism including a steering control motor and a torque control motor, and steering is performed by a driver's steering wheel operation, and the steering control motor is rotationally controlled by image data in front of the vehicle. In the automatic steering device that automatically steers the tire side with the torque control motor to control the torque on the steering wheel side, the driver determines whether the driver holds the steering wheel when the system starts to start controlling the automatic steering device. Is a torque control motor that rotates the handle-side input shaft, and when gripping, the steering control motor rotates the tire-side output shaft to turn on and off the output shaft to control the origin of the automatic steering device. Method. 2. When the system is started up, the input shaft is further temporarily fixed by a torque control motor, the arm force of each driver is checked by the signal of the steering torque sensor, and the driver's steering intention is judged based on the arm force of the driver. The method for controlling an automatic steering device according to claim 1, wherein a threshold value for setting is set.