JPH0826128A - Method for diagnosing failure of automatic steering device - Google Patents

Abstract

PURPOSE:To diagnose in detail failures of a motor part consisting of a steering control motor and a torque control motor, a mechanical part consisting of a gear ratio variable mechanism, and a sensor part to detect the steering condition, and realize the correct fail-sale depending on the region of the failures. CONSTITUTION:A gear ratio variable mechanism 25 is interposed in a steering device of a vehicle, and a steering control motor 36 is provided on this gear ratio variable mechanism 25 so that the tire side may be automatically or manually steered, and a torque control motor 38 is provided on a steering wheel side so that the steering reaction may be canceled to allow manual or automatic steering control. Presence or absence of failures in the motor part, the mechanical part or the sensor parts is diagnosed by the signal pattern of three kinds of sensors 40, 42, 43 to respectively detect the steering angle on the steering wheel side, the turning angle on the tire side, and the working condition of the steering control motor 36 when the system is started.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for diagnosing a failure of an automatic steering device which is electronically automatically steered by being used in a driving assistance system (ADA) of a vehicle such as an automobile. The present invention relates to a failure diagnosis of a mechanical section including a gear ratio variable mechanism based on signals from a plurality of sensors, a motor section including a steering control motor and a torque control motor, and a sensor section for detecting a steering condition, and a fail safe method at the time of failure. .

[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 automatically brake when there is a danger of a rear-end collision due to an error in driving operation, to correct the steering wheel in the event of cross wind, and to avoid obstacles. The limited automatic travel function is to maintain a safe inter-vehicle distance 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. Further, in the case of steering control, it is conceivable to provide, for example, three types of sensors that detect the steering angle on the steering wheel side, the steering angle on the tire side, and the operating state of the steering control motor. 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. In the automatic steering mode, the driver is assisted in various modes by controlling the two motors.

Therefore, if the whole ADA system is roughly classified, it is composed of two motors for steering control and torque control, a mechanical part of a gear ratio variable mechanism, and a sensor for detecting a steering condition. It is necessary to diagnose whether or not there is a failure. In this case, since there are three types of sensors, it is preferable to utilize these sensor signals for fault diagnosis. Further, since different problems occur depending on the location of the failure, it is possible to finely diagnose whether the failure is in the motor section, the mechanical section or the sensor section. And it is required to properly perform fail-safe according to the location of each failure.

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 steering wheel side and the tire side of the steering operation system are configured separately. Then, the shift amount of the vehicle position with respect to the traveling system road is calculated based on the image data, and the automatic steering actuator on the tire side is operated based on the shift amount and the steering operation state of the driver to constantly steer the vehicle electronically. It is shown.

[0007]

By the way, in the above-mentioned prior art, since the steering wheel is always electronically steered with respect to the driver's operation of the steering wheel, it is applicable to the failure diagnosis which is the object of the present invention. Can not. Further, in the configuration of the prior art, mechanical manual steering cannot be performed, and therefore, there is a problem in that it is impossible to steer the vehicle for traveling at the time of failure.

In view of the above points, the present invention provides detailed diagnosis of the failure of the motor section, the mechanical section, and the sensor section in the system capable of manual steering and automatic steering, and determines the failure according to the location of the failure. The purpose is to be fail-safe.

[0009]

In order to achieve this object, the present invention provides a steering device of a vehicle with a mechanical portion including a gear ratio variable mechanism, and the gear ratio variable mechanism automatically steers the tire side. In the automatic steering device for manual steering or automatic steering control, the automatic steering device is started to be controlled by providing a motor unit composed of a steering side control motor capable of manual steering and a torque control motor for canceling the steering reaction force on the steering wheel side. It is possible to diagnose whether there is a failure in the motor unit, mechanical unit or sensor unit by the signal pattern from the sensor unit that detects the steering angle on the steering wheel side, the steering angle on the tire side, and the operation of the steering control motor when the system is started. Characterize.

[0010]

In the present invention based on the above control method, when the driver grasps the steering wheel to judge the intention of steering by the signals of the steering angle sensor, the turning angle sensor, etc., the operation of the steering control motor and the gear ratio variable mechanism are used. The tire side is manually steered based on the driver's steering wheel operation. Further, when it is determined that the driver releases the steering wheel, the tire side is automatically steered by the operation of the steering control motor, the torque control motor, and the gear ratio variable mechanism. At this time, if the above-mentioned control is normal, at least two signals of three types of sensors for respectively detecting the steering angle on the steering wheel side, the turning angle on the tire side, and the operation of the steering control motor are changed patterns.
Therefore, by determining a pattern other than this, a special pattern while the vehicle is traveling, or the like, the presence or absence of a failure in the motor unit, the mechanical unit, or the sensor unit can be easily and finely diagnosed.

[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 is started immediately after the engine is started. The origin finding 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, and changes the steering wheel steering angle Qh and the tire turning angle Qp. The shafts 21 and 22 are aligned so that they coincide with each other. The threshold setting unit 51 temporarily fixes the steering wheel 9 by the torque control motor 38 at a safe extremely low speed, and at this time, checks the magnitude of the individual driver's arm force by the signal of the steering torque sensor 41, and based on the driver's arm force. A threshold value a for determining whether the driver intends to steer the vehicle or let it go.

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, signals of the steering wheel steering angle Qh, the tire turning angle Qp, the vehicle speed V, the image data, and the steering torque Th are input to the steering control unit 53, and the motor is controlled in accordance with each mode after the origin is found.

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. .

Further, the failure diagnosis and the fail-safe control system at the time of failure will be described. Explaining the method of failure diagnosis, the steering angle Qh on the steering wheel side and the steering angle Q on the tire side.
Since there are three types of sensors 40, 42, 43 that detect the operation of the steering wheel p and the steering control motor 36, these sensor signals can be used for failure diagnosis. Here, since the sensor signals of the steering angle Qh and the turning angle Qp are different in the origin search, manual steering, and automatic steering, the failure diagnosis cannot be made only by these two sensor signals, but the failure diagnosis is made by adding the signal of the phase angle sensor 43. it can. In addition, three types of sensors 40, 4
The two motors 36, 38 are driven by the signal patterns of 2, 43.
It is also possible to determine the failure part of the motor part, the mechanical part of the gear ratio variable mechanism 25, or the sensor part. If the motor section and the mechanical section are normal as fail-safe at the time of failure, steering in the manual steering mode is possible.

Therefore, a failure diagnosing section 54 to which the signals of the three types of sensors 40, 42 and 43 are input is provided, and the presence or absence of a failure and the failure location are diagnosed by the signal pattern during system operation. When a failure occurs, the alarm lamp 55 is turned on, and when the failure location is a sensor section or the like, the steering control section 53 is instructed to fix the manual steering.

Next, the operation of this embodiment will be described. First, immediately after the engine is started, it is determined whether or not the driver holds the steering wheel 9, and when the driver releases the steering wheel 9, the torque control motor 38 rotates the input shaft 21, and when the driver holds the steering wheel 9, the steering control motor 36 drives the output shaft 22. The rotation is performed and the origin is set so that the tire steering angle Qp and the steering wheel steering angle Qh match. Further, the input shaft 21 is fixed by the torque control motor 38 in a safe running state at an extremely low speed, the steering torque sensor 41 in this case detects the arm force when the driver operates the steering wheel, and the threshold value a is determined based on this arm force. To do.

Thereafter, the steering torque Th is compared with a threshold value a,
When the driver's intention to actually hold the steering wheel 9 is determined by Th ≧ a, the steering control motor 36 causes the sun gear 3 to rotate.
1 is fixed and the torque control motor 38 is made free to switch to the manual steering mode. Then, when the driver operates the steering wheel, the input shaft 21 and the gear ratio variable mechanism 25
First and second gears 26, 27, fixed sun gear 31
The output shaft 22 is rotated in the same direction by the operation of the planetary gears 30 and the front wheels 5 are freely steered left and right by the operation of the hydraulic power steering mechanism 23.

On the other hand, if it is determined that Th <a is not released, the automatic steering mode is set. 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.
Since a heavy load is applied to the ring gear 32 on the tire side, the carrier 34 and the like reversely rotate and the steering reaction force in this case acts on the steering wheel 9 side. At this time, the torque control motor 38 and the worm gear 37 are actuated to operate the input shaft 21, the first
Since the torque is assisted to fix the gear 26, the carrier 34, etc. of the ring gear 3 by the rotation of the sun gear 31 by the steering control motor 36, the ring gear 3 resists the load on the tire side.
2, the second gear 27 and the output shaft 22 rotate, and the front wheels 5 are 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.

The failure diagnosis and the fail-safe control at the time of failure will be described with reference to the flowchart of FIG. First, immediately after the engine is started, the power supply of the system 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, turn the system power on
When N is started, the process proceeds to step S3 to start the operation of the steering control motor 36, and in step S4 the operation of the torque control motor 38 is started. Then, in step S5, the signal patterns of the three types of sensors 40, 42, 43 are checked.

Here, the signal patterns of the three types of sensors 40, 42 and 43 are shown in eight types a to h in Table 1 below.

[Table 1] In Table 1, 1 indicates that the sensor signal has changed, and 0 indicates that the sensor signal has not changed.

In Table 1, when all sensor signals a are changed, the steering control motor 36 automatically steers the tire side, and the torque control motor 38 steers the steering reaction force while the driver holds the steering wheel 9 at this time. This shows normal steering in the automatic steering mode in which the steering angle Qh is changed by operating so as to cancel the above. e is a case where the driver releases the steering wheel and the steering angle Qh does not change due to automatic steering similarly.
In this case as well, normal automatic steering mode steering is indicated. When all the sensor signals of h do not change, it indicates a normal steering operation stopped state. When only the steering angle Qh and the steered angle Qp of b change, normal steering in the manual steering mode is indicated.

When the steering angle Qh and the steered angle Qp change in this way, the changes in the angular velocities ωh and ωp are further checked. If they are normal, the four sensor signals change together. If any one of them does not change as in the above, it means that the sensor unit is abnormal. Also, since at least any two sensor signals change during normal operation, d, f, g
If only one of the sensor signals changes, it indicates an abnormality in the mechanical section. When the vehicle is stopped, c indicates a case where the steering control motor 36 is in a free state and the torque control motor 38 normally returns the origin to change the steering angle Qh and the phase angle Qs. On the other hand, this signal pattern is generated while the vehicle is traveling, and under the condition that the steering torque Th signal is output and the driver holds the steering wheel 9 in this case, the steering control motor 36 indicates a runaway. Further, under the condition that the steering wheel is released, the steering reaction force escapes to the steering wheel side due to a failure of the torque control motor 38 during automatic steering, and the tire cannot be cut.

Therefore, in step S5, three types of sensors 4 are used.
By checking which of the signal patterns 0, 42 and 43 corresponds to Table 1, it is possible to easily and finely diagnose the presence or absence of a failure. Then, when the normal origin is found, and automatic steering or manual steering is judged, the vehicle exits as it is. On the other hand, if a failure is diagnosed, steps S5 to S6
If there is a failure in the mechanical parts d, f, g or if the steering control motor 36 of c is running while the vehicle is traveling, the process proceeds to step S7 to stop the control and warn that the vehicle cannot run. . If the sensor unit or the torque control motor 38 fails, the process proceeds from step S6 to step S8, the sun gear is fixed by the steering control motor 36, and the manual steering mode is fixed in step S9. Therefore, in this case, the driver can operate the steering wheel to steer the vehicle to drive the vehicle normally.

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.

[0032]

As described above, according to the present invention,
In an automatic steering device capable of manual steering and automatic steering, three types of sensor signal patterns are used to detect the steering angle on the steering wheel side, the turning angle on the tire side, and the operation of the steering control motor when the system of the automatic steering device is activated. Since the presence or absence of a failure in the motor unit including the steering control motor and the torque control motor, the mechanical unit including the gear ratio variable mechanism, or the sensor unit for detecting the steering condition is diagnosed, a simple and detailed failure diagnosis can be performed. For this reason, the safety of the ADA system is improved, and the manual steering mode can be utilized to the maximum in fail-safe at the time of failure. When the sensor unit or the torque control motor is out of order, the fail-safe operation is performed so that the manual steering mode is fixed. Therefore, the driver can operate the steering wheel to drive the vehicle normally and go to a maintenance shop.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an automatic steering control unit suitable for a failure diagnosis 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 failure diagnosis and a fail safe at the time of failure.

[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 25 gear ratio variable mechanism 36 steering control motor 38 torque control motor 40 steering angle sensor 42 steering angle sensor 43 phase angle sensor 54 failure diagnosis Department

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Claims (4)

[Claims] 1. A steering unit of a vehicle is provided with a mechanical section including a gear ratio variable mechanism, and the gear ratio variable mechanism has a steering side control motor capable of automatically steering or manually steering the tire side, and a steering wheel side steering. In an automatic steering device that is equipped with a motor unit consisting of a torque control motor that cancels the reaction force and controls the manual steering or automatic steering, the steering angle on the steering wheel side and the steering on the tire side when the system starts to control the automatic steering device. A failure diagnosis method for an automatic steering device, characterized by diagnosing whether or not there is a failure in a motor section, a mechanical section or a sensor section based on a signal pattern from a sensor section that detects the operation of each of the angle and steering control motor. 2. The fault diagnosis of the automatic steering device according to claim 1, wherein a fault of either the steering control motor or the torque control motor is diagnosed by adding a steering torque signal to the signal pattern from the sensor section. Method. 3. When the sensor signals of the steering angle and the turning angle both change, the sensor signals of the angular velocities are checked, and if any of the four sensor signals does not change, the failure of the sensor unit is diagnosed. The fault diagnosis method for an automatic steering device according to claim 1, wherein: 4. The method of diagnosing a failure of an automatic steering device according to claim 1, wherein when the sensor unit or the torque control motor fails, the manual steering mode is fixed.