JPH06336170A - Control method for automatic steering device - Google Patents

Abstract

PURPOSE:To quickly switch the automatic steering mode to the manual steering mode in emergency in an automatic steering device optionally switching the manual steering by a driver and the automatic steering using image data to steer a vehicle. CONSTITUTION:A gear ratio changing mechanism 25 having a steering control motor 36 and a torque control motor 38 is provided on the steering device 10 of a vehicle 1. In the automatic steering mode, the steering control motor 36 is operated in response to the indicated steering angle via the image data in front of the vehicle 1 and the signals of the vehicle speed and the actual steering angle, and the running vehicle 1 is automatically steered along the white line or the like on a road without a steering wheel operation. When the intention of a driver is shown on the steering wheel to be judged as a steering wheel operation in the automatic steering mode, the automatic steering mode is immediately switched to the manual steering mode, and the vehicle 1 can be manually steered thereafter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method of an automatic steering device which is electronically used for a driving assistance system (ADA) of a vehicle such as an automobile and which is electronically steered. Switching control.

[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 Active Drive Assist system (ADA) 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 automatically brake when there is a risk of a rear-end collision due to an error in driving operation or to correct the steering wheel in case of cross wind. The limited automatic traveling function is to perform automatic steering on behalf of the driver for lane following traveling, avoid obstacles automatically, and maintain a safe inter-vehicle distance.

The above ADA system will be described more specifically. For example, Japanese Patent Application No. 4-653 filed 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 the application of Japanese Patent Laid-Open No. 3-238809, a planetary gear type system having a steering control motor and a torque control motor in a steering system of a steering device is used. A gear ratio variable mechanism is provided. Then, the steering angle along the white lane of the lane is calculated from the image data, etc., and a current corresponding to this steering angle is supplied to the steering control motor to operate the gear ratio variable mechanism to automatically steer the tire side. However, it is considered that the vehicle autonomously follows the lane. This system has been made more concrete by the development of the most important image recognition technology, and it is necessary to further develop the technology in various points in order to put it into practical use.

Here, the automatic steering device using the image data is configured, for example, to switch to the automatic steering mode by a switch operation by a driver or to release the mode and switch to the manual steering mode. However, during automatic steering, the driver's judgment may suddenly correct the behavior of the vehicle body due to a crosswind, or manually steer to change lanes.
In such an emergency, it is desired to quickly switch to the manual steering mode by using an appropriate means other than the switch operation.

Conventionally, as for the above-mentioned automatic steering device, there is a prior art disclosed in, for example, Japanese Patent Laid-Open No. 3-276310. In this prior art, an unmanned moving vehicle is targeted, a predicted position and a target position of the own vehicle after a predetermined time are set, and a control amount is calculated from a deviation between the two. Further, it is shown that the control amount is corrected based on the distance between the current vehicle position and the predicted position to control the traveling.

[0007]

By the way, in the above-mentioned prior art, since it is a system in which an unmanned moving vehicle travels only by automatic steering, it cannot be applied to manual steering switching control. .

In view of the above, the present invention provides an automatic steering system for steering a vehicle by arbitrarily switching between a manual steering by a driver and an automatic steering mode using image data or the like. The purpose is to switch control to the manual steering mode quickly at times.

[0009]

In order to achieve this object, the present invention provides a steering system for a vehicle, which is provided with a steering ratio control motor and a torque control motor, and is provided with a gear ratio variable mechanism for automatically steering. In this case, one or both of the steering control motor and the torque control motor are operated according to the image data in front of the vehicle, the vehicle speed, and the signal of the actual steering angle, so that the running vehicle follows the white line of the road without operating the steering wheel. In an automatic steering device that automatically steers, determines whether the driver is operating the steering wheel in the automatic steering mode,
The feature is that the mode is switched to the manual steering mode as soon as the steering wheel operation is determined.

[0010]

In the present invention based on the above control method, when the automatic steering mode is set while the vehicle is traveling, image data in front of the vehicle,
Instructed steering angle is calculated based on the relationship between the vehicle speed and the actual steering angle signal, for example, the white line of the road and the vehicle, and a current corresponding to this instructed steering angle flows to the steering control motor of the gear ratio variable mechanism to operate, Even if the driver does not operate the steering wheel, the front wheels will automatically steer and safely follow the lane along the white line. Then, in the automatic steering mode, when the driver needs to steer and operates the steering wheel, it is immediately switched to the manual steering mode, and the manual steering can be performed quickly and arbitrarily.

[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 when the driver's brake operation is insufficient, the safe distance between vehicles can be maintained and the vehicle can travel safely. 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. Even if the driver does not operate the steering wheel, it is possible to safely follow the lane.

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 worm gear 35 that reversibly rotates when a steering torque equal to or greater than a predetermined torque is applied to the input shaft 21.
A torque control motor 38 is connected via 7. 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.

Therefore, the worm gear 35 is used to drive the motor shaft 2
When the driver steers the handle 9 while the sun gear 31 of No. 4 is 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 with respect to the fixed sun gear 31. Then, 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. When the steering control motor 36 is operated and the worm gear 35 and the sun gear 31 are rotated by the motor shaft 24 while the input shaft 21 is fixed by the torque control motor 38 and torque assist is performed to cancel the steering reaction force, the pinion 33 is rotated. The output shaft 22 is electrically rotated by rotating the output shaft 22 via the ring gear 32 and the second gear 27.

As a control system, the input shaft 21 has a steering angle Qh.
Is provided with a steering angle sensor 40 for detecting the steering torque Th, and a steering angle sensor 42 for detecting the actual steering angle Qp 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. Then, 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, and the steering signal is transmitted in the automatic steering mode. Output to the steering control motor 36,
It is configured to output a torque signal to the torque control motor 38.

In FIG. 1, the automatic steering control unit 17
Will be described. First, it has a distance calculation unit 50 to which the image data from the image recognition control unit 15 is input,
As described above, the predetermined distance position D on the image is set. The target trajectory setting unit 51 sets the target trajectory L1 by the white line at the predetermined distance position D based on the image data. Further, the vehicle has a predicted trajectory calculation unit 52 for inputting the vehicle speed V and the actual steering angle Qp, and calculates a predicted trajectory L2 of the vehicle 1 when traveling at a predetermined distance position D with the current position, direction, and traveling state of the vehicle. To do. Furthermore,
It has a mode setting unit 53 for setting, for example, an automatic steering mode in which the power of the control system is turned on and a manual steering mode in which the power is turned off by turning the selection switch 45 on and off.

The above-mentioned target trajectory L1, predicted trajectory L2 and mode signal are input to the deviation width calculator 54 to calculate the deviation width e between the target trajectory L1 and the predicted trajectory L2 in the automatic steering mode. The deviation width e is input to the steering angle calculation unit 55, and the indicated steering angle φ is calculated from the deviation width e and the proportional constant k. The instructed rudder angle φ and the actual rudder angle Qp are input to the control amount calculation unit 56, the control amount C is calculated from the deviation between the two, and the drive unit 57 supplies the steering control motor 36 with a current Ip corresponding to the control amount C. . Further, the steering torque Th of the steering torque sensor 41 is provided with an assist torque calculator 58, which detects the steering torque Th corresponding to the steering reaction force acting on the steering wheel 9 side in the automatic steering mode, and the steering reaction force Th is detected. The assist torque Ta that cancels out is calculated. Then, the drive unit 59 is configured to supply the current Is according to the torque Ta to the torque control motor 38.

In the above control system, the mode switching control in an emergency will be described. When the driver wants to steer manually while traveling in the automatic steering mode, the driver's intention directly appears as the operation of the steering wheel 9. Therefore, it is most suitable to switch the mode by using the driver's steering wheel operation. Therefore, the steering wheel operation determination unit 60 to which the steering torque Th is input is provided, and the steering wheel operation of the driver is determined when the predetermined steering torque Th continues for the predetermined time t by the timer 61. Then, the steering wheel operation signal is input to the mode setting unit 53 so as to immediately switch to the manual steering mode in the automatic steering mode.

Next, the operation of this embodiment will be described. First, when the driver turns off the selection switch 45 while the vehicle is traveling, the automatic steering control unit 17 enters the manual steering mode. Therefore, in the gear ratio variable mechanism 25 of the automatic steering power unit 14, the steering control motor 36 does not operate when it is not energized, but the motor shaft 24 is fixed by the worm gear 35 during normal steering operation. Further, the torque control motor 38 is also de-energized and deactivated, and the input shaft 2
1 becomes free. Therefore, the driver is shown in Figure 5 (a).
When the steering wheel 9 is gripped and steered as described above, the output shaft 22 rotates in the same direction by the operation of the planetary gear 30 with respect to the input shaft 21, the first and second gears 26 and 27 of the gear ratio variable mechanism 25, and the fixed sun gear 31. Then, the front wheels 5 are freely steered left and right by the operation of the hydraulic power steering mechanism 23.

When the selection switch 45 is turned on, the automatic steering mode is selected. Therefore, in the automatic steering control unit 17, the target trajectory L1 such as the white line at the predetermined distance position D is set by the image data from the image recognition control unit 15, and the predetermined distance position D of the vehicle 1 is set by the vehicle speed V and the actual steering angle Qp.
The predicted trajectory L2 at is calculated. Then, the instructed steering angle φ is calculated according to the deviation width e between the target trajectory L1 and the predicted trajectory L2, and the steering control motor 36 is supplied with a current Ip of a control amount based on the instructed steering angle φ and the actual steering angle Qp. Therefore, in the gear ratio variable mechanism 25, the steering control motor 36 operates to rotate the worm gear 35, the motor shaft 24, and the sun gear 31, but at this time, since the ring gear 32 is heavily loaded on the tire side, the carrier 34 Etc. are reversed and the steering reaction force in this case acts on the steering wheel 9 side.

Then, the steering torque sensor 41 detects the steering reaction force in this case, the assist torque Ta for canceling the steering reaction force is calculated, and the current Is corresponding to the torque Ta flows into the torque control motor 38. Then, the torque control motor 38 and the worm gear 37 are actuated so that the input shaft 21, the first gear 26, the carrier 34, etc. are always fixed. Therefore, the rotation of the sun gear 31 by the steering control motor 36 causes the ring gear 32, the second gear 27, and the output shaft 22 to rotate against the load on the tire side.
The front wheels 5 are automatically steered according to the steering signal in the state where the steering wheel is released as shown in FIG. In this way, even if the driver does not operate the steering wheel 9, the front wheels 5 of the vehicle 1 are steered so as to follow the white line of the road, and the vehicle 1 safely follows the lane.

Actually, the input shaft 21 is constructed by connecting the handle shaft and the gear shaft with a torsion rod, and the steering torque sensor 41 is arranged between the handle shaft and the gear shaft. Therefore, when the gear shaft is fixed by the torque assist of the torque control motor 38, the output signal of the steering torque sensor 41 becomes zero, and the steering torque on the steering wheel 9 side can also be detected. The twist bar also allows the driver to operate the steering wheel 9 to some extent to generate steering torque.

The mode switching control in the automatic steering mode will be described with reference to the flowchart of FIG. First, when the automatic steering mode is determined in step S1, step S
2, the steering control motor 36 is operated, and step S3
Then, the torque control motor 38 is operated. Then step S
In step 4, the steering torque Th and the time t are compared with the set values Ths and ts to determine whether or not the driver is operating the steering wheel, and one or both of the steering torque Th and the time t are set values Ths and ts or less. When it is determined that the steering wheel is not operated, the process returns to step S2 and the automatic steering control is continued.

On the other hand, for example, when the vehicle speed V is 30 km / h or more, the steering torque of 3 kg continues for 3 seconds, or the vehicle speed V is
If the steering torque is less than 30 km / h and the steering torque is 5 kg for 3 seconds, the driver's steering wheel operation is determined. When it is determined that the driver operates the steering wheel, the process proceeds to step S5 to immediately change the steering control motor 36 to the sun gear fixing mode, stop the operation of the torque control motor 38 in step S6, and release the steering wheel fixing control. Then, in step S7, the selection switch is turned off to switch to the manual steering mode, and the process ends. For this reason, when the driver suddenly feels the need for steering and operates the steering wheel 9, the automatic steering mode is immediately switched to the manual steering mode only by operating the steering wheel of the driver, and the behavior of the vehicle is promptly corrected against the cross wind. , Is steered to change lanes.

Although the embodiments of the present invention have been described above, it is also possible to supply the electric current of the steering signal to the torque control motor and perform the automatic steering control only by operating the motor.
It can be applied to this control system.

[0028]

As described above, according to the present invention,
In an automatic steering device that steers the vehicle by arbitrarily switching between manual steering by the driver and automatic steering mode using image data, etc., in the automatic steering mode, it is controlled to judge the driver's steering wheel operation and switch to manual steering Therefore, when the driver's intention appears on the steering wheel and an urgent need for steering occurs, it is possible to quickly respond. The actual steering wheel operation of the driver can be accurately determined based on the steering torque and the time.

[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 conceptual diagram of automatic steering control.

FIG. 5 is a diagram showing states of manual steering and automatic steering.

FIG. 6 is a flowchart showing manual steering switching control in the automatic steering mode.

[Explanation of symbols]

 DESCRIPTION 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 25 gear ratio variable mechanism 36 steering control motor 38 torque control motor 60 steering wheel operation determination unit 61 timer

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Claims (2)

[Claims] 1. A steering device for a vehicle is provided with a gear ratio variable mechanism that is equipped with a steering control motor and a torque control motor to automatically steer, and image data, vehicle speed, and actual steering angle in front of the vehicle in the automatic steering mode. In the automatic steering device, the steering control motor and / or the torque control motor are activated by the signal of to automatically steer the running vehicle along the white line on the road without operating the steering wheel. A method for controlling an automatic steering device, comprising: determining whether or not a driver is operating a steering wheel, and immediately switching to a manual steering mode when determining the steering wheel operation. 2. The control method for an automatic steering device according to claim 1, wherein the driver's steering wheel operation is determined when a predetermined steering torque continues for a predetermined time.