JP2001260908A - Vehicle steering system - Google Patents

Abstract

(57) [Summary] (With correction) [PROBLEMS] To mechanically connect a steering wheel and a wheel for safety in the event of a failure, a wheel turning position is connected in accordance with a steering wheel position. SOLUTION: At 41, a steering angle sensor detected value θ1 of a steering wheel is read, and at 42, 43, a steering reaction force motor angle is divided by a steering reaction force motor gear ratio to obtain a steering angle detection value θ2. When it is determined in 44 that the difference between θ1 and θ2 is smaller than the failure determination steering angle set value θs, the detected steering amount is normal, and in 45, the average value of both is set to the steering angle θ to perform steering control. To contribute. When the steering amount detection value is determined to be faulty at 44,
At 46, since the wheel turning position is shifted from the steering wheel steering position by θs, the position shift amount is obtained as a function of the set value θs, and at 61, the wheels are corrected and turned to eliminate the position shift. The steering motor is rotated reversely, and the shaft clutch is engaged at 62 to mechanically connect the upper and lower steering shafts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for mechanically transmitting steering force from a steering wheel to wheels.
The present invention relates to a steering apparatus for a so-called steer-by-wire type vehicle in which a steering amount of a steering wheel is detected, and a wheel is steered by a motor so that the wheel steering amount has a predetermined relationship. .

[0002]

2. Description of the Related Art A steering apparatus of this type includes a steering amount detecting means for detecting a steering amount by a steering wheel, a steering amount detecting means for detecting an actual steering amount of a wheel, and a steering motor for steering a wheel. In the event of a failure, the steering wheel and the wheels are connected by disconnecting means so that the wheels can be mechanically steered by the steering wheel so that the steering control system including It is customary to take safety measures. Conventionally, the mechanical connection or disconnection between the steering wheel and the wheel by the connecting / disconnecting means is simply performed when the steering wheel is steered by the steering motor as described in, for example, JP-A-11-1176. Releasing the mechanical connection between the steering wheel and the wheels by releasing the contact means, connecting the disconnection means when not turning the wheels by the steering motor, and mechanically connecting the steering wheel and the wheels, As a result, the steering could not be disabled.

[0003]

Therefore, conventionally, when the steering of the wheels by the steering motor is stopped so that the steering is not uncontrolled when a failure is detected, the connecting / disconnecting means is connected and the steering wheel and the steering wheel are disconnected. If the wheels are mechanically connected between the wheels, but before the connection, if the wheel steering position does not correspond to the steering position of the steering wheel due to the above failure,
Mechanical coupling between the steering wheel and the wheel is performed in a state where the steering wheel steering position and the wheel turning position are displaced from each other.

According to a first aspect of the present invention, the wheel steering position corresponds to the steering wheel steering position before the connecting / disconnecting means is connected and the steering wheel and the wheels are mechanically connected. It is an object of the present invention to solve the above-described problem by allowing the vehicle to be corrected and steered.

According to a second aspect of the present invention, there is provided a method for detecting a failure of a steering amount detecting means, which is effective when two steering amount detecting means are provided and an average value of both detected values is used for steering control. The purpose is to propose a modified steering system.

According to a third aspect of the present invention, there is provided a failure detection method of a steering amount detecting means effective when two steering amount detecting means are provided and one of the detected values is used for steering control, and correction steering of a wheel. The purpose is to propose a scheme.

According to a fourth aspect of the present invention, there is provided a failure detection method of a turning amount detecting means which is effective when two turning amount detecting means are provided and an average value of both detected values is used for steering control. It is an object of the present invention to propose a modified steering method for wheels.

According to a fifth aspect of the present invention, there is provided a method for detecting a failure of a turning amount detecting means and correcting a wheel effective when two turning amount detecting means are provided and one of the detected values is used for steering control. The purpose is to propose a steering method.

A sixth object of the present invention is to propose an effective failure detection method for a steering motor.

A seventh object of the present invention is to propose a method of correcting and turning a wheel which is effective when a failure of a turning motor is detected.

An eighth aspect of the present invention is directed to an accurate calculation of a deviation amount of a wheel steering position due to a failure of a steering motor.

A ninth aspect of the present invention is directed to propose a method for preventing a failed steering motor from affecting a correct steering of a wheel.

A tenth aspect of the present invention is directed to propose another method for preventing a failed steering motor from affecting a correct steering of a wheel.

[0014] An eleventh aspect of the present invention is directed to enabling a driver to be informed of a failure.

[0015]

To achieve these objects, a vehicle steering apparatus according to a first aspect of the present invention comprises a steering amount detecting means for detecting a steering amount by a steering wheel, and a turning amount detecting means for detecting an actual steering amount of a wheel. Steering amount detecting means, and the wheels are normally steered by a steering motor so that the steering amount and the steering amount detected by these means have a predetermined relationship.
When the steering amount detecting means, the steering amount detecting means or the steering motor is out of order, the steering wheel and the wheels are connected by the connecting / disconnecting means so that the wheels are mechanically steered by the steering wheel. Wherein the steering wheel is steered by the steering motor to a position corresponding to the steering position of the steering wheel before the steering wheel and the wheel are connected by the disconnecting / connecting means at the time of the failure. It is.
Vehicle steering system.

According to a second aspect of the present invention, in the vehicle steering apparatus according to the first aspect, the steering amount detecting means is provided as a pair, and an average value of the detected steering amount is used as a steering amount by a steering wheel for steering control. When the deviation between the detected steering amounts reaches a set value, it is determined that the steering amount detecting means has failed, and the wheel is steered by the steering motor in a direction in which the deviation corresponding to the set value is eliminated. After that, the steering wheel and the wheels are connected by the connecting / disconnecting means.

According to a third aspect of the present invention, in the vehicle steering system according to the first aspect, the steering amount detecting means is provided as a pair, and one of the detected steering amount values is used as a steering amount by a steering wheel for steering control. When it is determined that the steering amount detecting means has failed when the deviation between these steering amount detected values reaches a set value, and when it is determined that the steering amount detecting means related to the one steering amount detected value has failed at the time of the failure determination. The steering wheel is steered by the steering motor in a direction in which the deviation of the set value is eliminated, and then the steering wheel and the wheel are connected by the connection / disconnection means. It is.

According to a fourth aspect of the present invention, in the vehicle steering system according to any one of the first to third aspects, the steering amount detecting means is provided as a set of two, and the average value of the detected steering amount is calculated. A direction in which the deviation between the detected steering amounts is determined to be faulty when the deviation between the detected steering amounts reaches a set value, and the deviation corresponding to the set value is eliminated. After the wheel is steered by the steering motor, the steering wheel and the wheel are connected by the connecting / disconnecting means.

According to a fifth aspect of the present invention, there is provided a vehicle steering system according to any one of the first to third aspects, wherein the steering amount detecting means is provided as a set of two, and one of the detected steering amount values is used as a wheel. The steering amount is used as the steering amount, and when the deviation between the steering amount detection values reaches a set value, it is determined that the steering amount detection means has failed. Only when it is determined that the related steering amount detecting means has failed, after turning the wheel by the steering motor in the direction in which the deviation of the set value is eliminated, the steering wheel and the wheel are connected by the connecting / disconnecting means. It is characterized in that it is configured to connect between them.

According to a sixth aspect of the present invention, in the vehicle steering system according to any one of the first to fifth aspects, a deviation between a target steering amount corresponding to a steering amount by the steering wheel and a steering amount of the wheel is provided. The steering motor is configured to determine that the steering motor has failed when the state where is equal to or more than the set value has continued for the set time.

According to a seventh aspect of the present invention, in the vehicle steering system according to any one of the first to sixth aspects, the steering motor is provided as a set of two, and when it is determined that the steering motor has failed, After the wheel is steered by a normal steering motor so that the deviation of the wheel steering amount due to the failure is eliminated, the steering wheel and the wheel are connected by the connecting / disconnecting means. It is.

According to an eighth aspect of the present invention, in the vehicle steering apparatus according to the seventh aspect, the deviation of the wheel turning amount due to the failure of the turning motor is adjusted by the setting relating to the deviation between the target turning amount and the wheel turning amount. The value is obtained by adding the rotational speed of the failed steering motor and the integrated value of the set time to the value.

According to a ninth aspect of the present invention, in the vehicle steering system according to the seventh or eighth aspect, the steering motors provided as a pair are arranged in parallel to a wheel steering system, The motor is provided with a clutch capable of mechanically connecting and disconnecting with the wheel steering system, and is configured to turn off the failed steering motor and to disconnect from the wheel steering system by releasing the clutch at the same time. is there.

According to a tenth aspect of the present invention, there is provided a vehicle steering system comprising:
In the invention or the eighth invention, the steering motor provided as a pair of the two is disposed in series with the wheel steering system, and the wheel turning is performed by a transmission means that does not rotate in response to an input from the wheel. It is characterized in that it is configured to be drive-coupled to a rudder system to turn off a failed steering motor.

The vehicle steering apparatus according to the eleventh invention has a first
The invention according to any one of the inventions to the tenth invention, wherein the failure is alarmed.

[0026]

The vehicle steering system according to the first invention is generally
The wheels are turned by the turning motor such that the steering wheel steering amount and the wheel turning amount detected by the steering amount detecting means and the turning amount detecting means have a predetermined relationship. If the steering amount detecting means, the steering amount detecting means or the steering motor fails, the steering wheel and the wheels are connected by the connecting / disconnecting means, whereby the wheels can be mechanically steered by the steering wheel. Prevents uncontrolled steering of wheels at the time of failure.

According to the first aspect of the invention, prior to the connection between the steering wheel and the wheels by the disconnection means as described above, the wheels are corrected and steered by the steering motor to a position corresponding to the steering position of the steering wheel. With this configuration, the wheel turning position corresponds to the steering position of the steering wheel without fail before the connecting / disconnecting means mechanically connects the steering wheel and the wheel in response to the failure. It is possible to eliminate a problem that the mechanical coupling between the steering wheel and the wheel is performed in a state where the steering position and the wheel steering position are displaced from each other.

In the second invention, the average value of the detected steering amount by the steering amount detecting means provided as a pair is used as the steering amount by the steering wheel for the steering control, and the deviation between the detected steering amount values is set. It is determined that the steering amount detecting means has failed when the value becomes the value, and after the wheel is corrected and steered by the steering motor in a direction in which the deviation of the set value is eliminated,
In order to connect the steering wheel and the wheel by the connecting / disconnecting means, two steering amount detecting means are provided, and a failure detection method of the steering amount detecting means and a wheel failure detecting method are effective when an average value of the detected values of the two is used for steering control. A modified steering method can be proposed.

In the third invention, one of the steering amount detection values provided by the pair of steering amount detection means is used as the steering amount by the steering wheel in the steering control, and the deviation between the steering amount detection values is set to the set value. The deviation of the set value is eliminated only when it is determined that the steering amount detecting means has failed at the time of the failure, and only when it is determined at the time of the failure determination that the steering amount detecting means relating to the one steering amount detection value has failed. After the steering wheel is corrected and steered by the steering motor in the direction indicated by the arrow, in order to connect the steering wheel and the wheel by the disconnection means,
When two steering amount detecting means are provided and one of the detected values is used for steering control, it is possible to propose a failure detection method of the steering amount detecting means and a modified wheel turning method that are effective.

In the fourth aspect of the invention, the average value of the detected steering amount by the steering amount detecting means provided as a pair is used as the steering amount of the wheel in the steering control. When the deviation reaches the set value, it is determined that the steering amount detecting means has failed, the wheel is corrected and steered by the steering motor in a direction in which the deviation of the set value is eliminated, and then the steering wheel is connected by the connection / disconnection means. In order to connect between the wheels and the two wheels, two steering amount detecting means are provided, and a failure detection method of the steering amount detecting means and a corrected steering method of the wheels are effective when an average value of the detected values of the two is used for steering control. Can be suggested.

In the fifth invention, one of the steering amount detection values provided by the pair of steering amount detection means is used as a wheel steering amount for steering control, and a deviation between the steering amount detection values is used. Is determined to be a set value when the steering amount detecting means is out of order, and the set value is set only when it is determined that the steering amount detecting means related to the one of the steered amount detected values has failed in the failure determination. After the wheels are corrected and steered by the steering motor in the direction in which the minute deviation is eliminated, two steering amount detecting means are provided to connect the steering wheel and the wheels by the connecting / disconnecting means. It is possible to propose a failure detection method of the turning amount detection means and a wheel correction turning method that are effective when used for steering control.

In the sixth aspect of the present invention, when the deviation between the target turning amount corresponding to the steering amount of the steering wheel and the turning amount of the wheel is equal to or larger than a set value for a set time, the turning motor fails. Therefore, it is possible to simply and reliably detect the failure of the steering motor.

In the seventh invention, two steering motors are used.
When it is determined that the steering motor has failed as described above, the wheels are corrected and steered by the normal steering motor so that the deviation of the wheel steering amount due to the failure is eliminated, and then the connection and disconnection are performed. Since the steering wheel and the wheel are connected by the means, it is possible to propose an effective correction steering method of the wheel when the failure of the steering motor is detected.

In the eighth invention, the deviation of the wheel turning amount due to the failure of the turning motor is changed to the set value relating to the deviation between the target turning amount and the wheel turning amount by the rotation of the failed turning motor. Since the speed and the integrated value of the set time are obtained by adding, the deviation amount of the wheel turning position due to the failure of the turning motor can be obtained accurately by calculation.

According to the ninth aspect, the steering motors provided as a pair are arranged in parallel with the wheel steering system, and both steering motors are mechanically disconnected from the wheel steering system. Provide a clutch that can be engaged and turn off the failed steering motor and disconnect it from the wheel steering system by releasing the clutch at the same time, so that the failed steering motor does not affect the corrected steering of the wheels. Can be.

In the tenth aspect, the steering motors provided as a pair are arranged in series with respect to the wheel steering system, and the vehicle is driven by a transmission means which does not rotate in response to an input from the wheels. Since the failed steering motor is driven and coupled to the wheel steering system to turn off the failed steering motor, the failed steering motor does not affect the correct steering of the wheels without providing a clutch as in the ninth invention. Can be

In the eleventh invention, since the above-mentioned failure is warned, the failure can be notified to the driver.

[0038]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a steering apparatus for a vehicle according to an embodiment of the present invention. Reference numeral 1 denotes a steering shaft, which comprises an upper steering shaft 1a and a lower steering shaft 1b. A steering wheel 2 is connected to an upper end of the upper steering shaft 1a, and a lower end thereof is coaxially abutted with an upper end of the lower steering shaft 1b so that the two can be appropriately connected by a shaft clutch 3 serving as a disconnecting / connecting means.

A pinion 4 is provided at the lower end of the lower steering shaft 1b so as to rotate integrally therewith, and a rack 5 is meshed with the pinion 4 to constitute a rack-and-pinion type steering gear. Tie rods 7 of wheels 6 are connected to both ends of the rack 5 so that the wheels 6 are steered via the tie rods 7 when the rack 5 makes a stroke in the longitudinal direction due to the rotation of the pinion 4.

The upper steering shaft 1a further includes:
A steering angle sensor 8 as a steering amount detecting means for detecting a steering angle of the steering wheel 2 is provided, and a steering reaction force for applying a steering reaction force to the steering wheel 2 so that a predetermined steering force is required for steering. The force motor 9 is connected. The steering reaction force motor 9 has an encoder 9a for detecting the rotation angle (rotational position of the steering shaft 1a), and causes the encoder 9a to function as a steering amount detecting means like the steering angle sensor 8. The upper steering shaft 1a is further provided with a torque sensor 10 for detecting the steering torque of the steering wheel 2, and controls the steering reaction force motor 9 so that the steering torque detected by the sensor 10 becomes a target.

The lower steering shaft 1b further includes
A turning motor 1 for turning this to turn the wheels 6
1, a steering angle sensor 12 as a steering amount detecting means is provided, and a steering motor 11 has a built-in motor clutch 11a capable of appropriately releasing the drive coupling with the lower steering shaft 1b. In addition, pinion 4
The rack and pinion type steering gear constituted by the rack 5 is provided with a stroke sensor 13 for detecting a stroke amount of the rack 5, and functions as a turning amount detecting means like the turning angle sensor 12.

The shaft clutch 3 has the structure shown in FIG. 2 and includes a clutch plate 21 rotatably connected to a lower end of the upper steering shaft 1a, and a lower steering shaft 1b.
The clutch plate 22 is rotatably coupled to the upper end of the clutch case 22 and is housed in the clutch case 23 so as to face the clutch plate 22. The clutch plate 22 rotates together with the lower steering shaft 1b but cannot be displaced in the axial direction, and the clutch plate 21 rotates together with the upper steering shaft 1a and is displaceable in the axial direction. The clutch plate 21 is separated from the clutch plate 2 by a spring 24.
2, the shaft clutch 3 is normally maintained in the connected state. The magnet 25 is placed on the clutch plate 21 and the clutch case 23 is wound around the magnet 25.
When the coil 26 provided in the inside is energized, the magnet 25 is displaced upward in FIG. 2 along with the clutch plate 21 against the spring 24, so that the clutch plate 21 separates from the clutch plate 22 and the shaft clutch 3 is released. Shall be switched to

FIG. 3 is a functional block diagram showing the control system of the steering apparatus described above. The steering amount detecting means failure detecting section 31 and the turning amount detecting means failure detecting section 32 are shown.
Target turning angle calculating section 33, turning motor failure detecting section 3
4, a motor output calculation unit 35, and a steering position deviation elimination unit 3
6. Steering amount detecting means failure detecting unit 31
Is a first steering angle detection value θ1 detected by the steering angle sensor 8.
And a second steering angle detection value θ2 obtained from the steering reaction force motor angle detected by the encoder 9a in the steering reaction force motor 9, and the deviation between these steering angle detection values θ1 and θ2 is used for failure determination. When the steering angle is less than the set value, the steering amount detecting means 8,
Assuming that 9a is normal, the average value of the detected steering angles θ1 and θ2 is set as the steering wheel steering angle θ and supplied to the target turning angle calculation unit 33. Steering amount detecting means failure detecting unit 31
When the deviation between the detected steering angles θ1 and θ2 is equal to or larger than the failure-determining steering angle set value, the steering amount detection means 8, 9a determines that the failure has occurred and inputs a failure signal to the turning position deviation eliminating unit 36.

The turning amount detecting means failure detecting unit 32 detects the second turning angle obtained from the first turning angle detection value δ1 detected by the turning angle sensor 12 and the stroke of the rack 5 detected by the stroke sensor 13. The steering angle detection value δ2 is input, and when the deviation between the steering angle detection values δ1 and δ2 is less than the failure determination turning angle setting value, the turning amount detection means determines that the turning amount detecting means is normal. The average value of δ1 and δ2 is set as the wheel turning angle δ and is supplied to the turning motor failure detection unit 34. When the deviation between the detected steering angle values δ1 and δ2 is equal to or larger than the failure determination steering angle set value, the steering amount detection means failure detection unit 32 determines that the steering amount detection means is faulty and turns the failure signal. It is input to the displacement eliminating unit 36.

The target turning angle calculation unit 33 receives the vehicle speed VSP in addition to the steering wheel steering angle θ, and multiplies the steering wheel steering angle θ by a steering gear ratio that varies according to the vehicle speed VSP. δ0 is obtained, and this is input to the steering motor failure detection unit 34. The turning motor failure detecting unit 34 determines the deviation between the wheel turning angle δ output from the turning amount detecting unit failure detecting unit 32 and the target turning angle δ0 when the turning amount detecting unit is normal, to determine the failure. When the turning angle deviation setting value Δδs is less than the predetermined turning angle deviation value Δδs, or when the deviation is larger than this, the turning motor 11 is assumed to be normal, and the difference between the wheel turning angle δ and the target turning angle δ0 is determined. Is supplied to the motor output calculation unit 35. When the deviation between the wheel turning angle δ and the target turning angle δ0 is equal to or larger than the turning angle deviation setting value Δδs for failure determination for a set time, the turning motor 11 detects a fault. Is input to the turning position deviation eliminating unit 36.

The motor output calculator 35 drives the turning motor 11 so that the turning angle deviation Δδ between the wheel turning angle δ and the target turning angle δ0 disappears, and the wheels follow the target turning angle δ0. To steer. Therefore, the steering motor 11 can steer the wheels such that the steering angle θ and the steering angle δ have a predetermined relationship. The predetermined relationship between the steering angle θ and the turning angle δ is determined not only according to the vehicle speed VSP as described above as the steering gear ratio when the target turning angle δ0 is obtained, but also the yaw rate acting on the vehicle. In addition, if it is determined according to the vehicle lateral motion such as lateral acceleration, more fine-grained steering control is possible.

When the steering position deviation canceling unit 36 receives a failure signal of the steering amount detecting means 8, 9a from the steering amount detecting means failure detecting unit 31, the wheel steering position becomes the steering angle for the failure determination. Since the steering wheel is shifted from the steering wheel steering position by the set value, the steering motor 11 is rotated in the reverse direction to correct and steer the wheels so as to eliminate the shift, and then the shaft clutch 3 is engaged to connect the upper and lower steering shafts 1.
a and 1b are mechanically connected. When receiving a failure signal of the turning angle detecting means from the turning amount detecting means failure detecting section 32, the turning position deviation eliminating section 36 sets the wheel turning position to the above-mentioned turning angle setting value for the failure determination. Since the steering wheel is deviated from the steering wheel position by a distance, the steering motor 11 is reversely rotated to correct and steer the wheels so as to eliminate the deviation, and then the shaft clutch 3 is engaged to connect the upper and lower steering shafts 1a, 1b. A mechanical connection is made between them. Further, the turning position deviation eliminating section 36 is provided with the turning motor failure detecting section 3.
When a failure signal of the steering motor 11 is received from the steering wheel 4, the steering motor 11 is turned off and the motor clutch 11a is released at the same time, and the shaft clutch 3 is connected to mechanically connect the upper and lower steering shafts 1a and 1b. .

When the control in FIG. 3 is performed by a microcomputer, the control program is as shown in FIG. Steps 41 to 45 in FIG. 4 correspond to the steering amount detecting means failure detecting unit 31 in FIG.
51 corresponds to the turning amount detecting means failure detecting unit 32, step 53 corresponds to the target turning angle calculating unit 33, and step 54 corresponds to
To 57 correspond to the steering motor failure detection unit 34, and step 58 corresponds to the motor output calculation unit 35.
Reference numerals 52, 60 to 62 correspond to the turning position deviation eliminating unit 36.

In step 41, the steering angle sensor 8
Is set as the first steering angle detection value θ1, and
In step 43, the steering reaction force motor angle detected by the encoder 9a in the steering reaction force motor 9 is read, and in step 43, a value obtained by dividing the steering reaction force motor angle by the motor gear ratio of the steering reaction force motor 9 is referred to as a second value. The detected steering angle is θ2. In step 44, these detected steering angle values θ1, θ2
It is checked whether or not the absolute value of the difference between them is less than the failure-determining steering angle set value θs.
a is normal, and in step 45, the average value of the detected steering angles θ1 and θ2 is used as the steering wheel steering angle θ.
To be used for steering control. When it is determined in step 44 that the absolute value of the difference between the steering angle detection values θ1 and θ2 has reached the failure determination steering angle setting value θs, the steering amount detection means 8, 9a issues a failure signal as a failure,
In step 46, since the wheel turning position is displaced from the steering wheel steering position by the failure determination steering angle setting value θs, the positional deviation amount is obtained as a function of the setting value θs.

In step 47, the detected value of the steering angle sensor 12 is set as a first detected steering angle value δ1, and in step 48, the stroke of the rack 5 detected by the stroke sensor 13 is read. The value obtained by dividing the value by the gear radius of the pinion 4 is
Is the detected steering angle value δ2. In step 50, it is determined whether or not the absolute value of the difference between the detected steering angle values δ1 and δ2 is less than a failure-determining steering angle setting value δs. Assuming that the detection means is normal, the steering switch 51 sets the average value of the detected steering angles δ1 and δ2 as the wheel steering angle δ. In step 50, the absolute value of the difference between the detected steering angle values δ1 and δ2 is the steering angle setting value δ for failure determination.
When it is determined that the steering angle is equal to or more than s, the steering angle detection means issues a failure signal indicating that the steering wheel is in failure. In step 52, the wheel steering position is shifted from the steering wheel steering position by the failure determination steering angle set value δs. Therefore, the displacement amount is obtained as a function of the set value δs.

In step 53, the steering wheel steering angle θ obtained in step 45 and the steering gear ratio G corresponding to the vehicle speed VSP, the vehicle yaw rate and the vehicle lateral acceleration are determined.
The target steering angle δ0 is obtained by multiplication with str. In step 54, the wheel steering angle δ obtained in steps 51 and 53
It is checked whether or not the steering motor 11 is normal based on whether or not the absolute value of the difference between the target steering angle δ0 and the target steering angle δ0 is less than the failure determination steering angle deviation set value Δδs. ), The timer TM is repeatedly reset in step 55, and then in step 58, the turning motor 11 is driven so that the turning angle deviation Δδ between the wheel turning angle δ and the target turning angle δ0 disappears. Is turned so as to follow the target turning angle δ0. Further, in step 59, the steering reaction force motor 9 is controlled so that the steering reaction force to the steering wheel 2 becomes a predetermined value.

While it is determined in step 54 that the absolute value of the difference between the wheel turning angle δ and the target turning angle δ0 is equal to or larger than the failure determination turning angle deviation set value Δδs, in step 56, The timer TM is incremented, and the time during which the absolute value of the difference between the wheel turning angle δ and the target turning angle δ0 is equal to or greater than the failure determination turning angle deviation set value Δδs is determined by the timer T.
Measure with M. Before this time TM becomes equal to the failure determination set time TMs, the turning motor 11 is not yet determined to be faulty in order to prevent erroneous determination due to a response delay during the transition of steering control, and control is performed at step 58, 59, but when the time TM becomes equal to the failure determination set time TMs, that is, the absolute value of the difference between the wheel steering angle δ and the target steering angle δ0 becomes the failure determination steering angle deviation set value Δδs. When the above state continues for the set time TMs, it is determined that the steering motor 11 has failed, and in step 60, the failure is warned and the steering motor 11 is connected to the motor clutch 11a.
Is released from the upper steering shaft a, and the steering motor 11 is turned off. Then, at step 62, the shaft clutch 3 is engaged to mechanically connect the upper and lower steering shafts 1a, 1b.

At step 44, it is determined that the steering amount detecting means has failed, and at step 46, the deviation amount f of the wheel turning position is determined.
When (θs) is obtained, in step 61, the turning motor 1 is turned to correct and turn the wheels so as to eliminate the positional deviation.
After the reverse rotation of the shaft 1, the shaft clutch 3 is engaged in step 62 to mechanically connect the upper and lower steering shafts 1a and 1b. When it is determined in step 50 that the steering amount detecting means has failed, and when the positional deviation amount f (δs) of the wheel steering position is obtained in step 52, the wheels are corrected and rotated in step 61 to eliminate the positional deviation. After the steering motor 11 is rotated in the reverse direction to steer, the shaft clutch 3 is engaged in step 62 and the upper and lower steering shafts 1a, 1a,
1b is mechanically connected.

According to the steering control according to the present embodiment as described above, the steering amount detecting means 8, 9a and the turning amount detecting means 1
When the steering motor 2, 13 or the steering motor 11 fails, the steering wheel 2 and the wheel 6 are connected by the shaft clutch 3 (step 62), whereby the wheels can be mechanically steered by the steering wheel. Can be prevented from becoming uncontrolled. When the steering amount detecting means 8, 9a or the turning amount detecting means 12, 13 fails, the wheel 6 is turned by the turning motor 11 before the steering wheel 2 and the wheel 6 are connected by the shaft clutch 3 as described above. In order to correct the steering to a position corresponding to the steering position of the steering wheel 2, the shaft clutch 3 is used to prevent the steering of the wheels from being uncontrolled when a failure occurs.
Before the mechanical connection between the wheels 6 is performed, the wheel steering position surely corresponds to the steering position of the steering wheel, and the steering wheel steering position and the wheel steering position remain displaced from each other. In this state, it is possible to eliminate the adverse effect of the mechanical coupling between the steering wheel and the wheels.

It should be noted that the steering angle setting value θs for failure determination in step 44 is additionally described. Since the steering amount detecting means 8 and 9a read the rotation at a mechanically integrated portion, the steering angle detection values θ1 and θ2 obtained by the two are used. Should agree in theory. However, in practice, the detected steering angle values θ1 and θ2 do not match due to differences in the occurrence of mechanical play in the steering amount detection means 8, 9a, differences in detection errors, and the like. Therefore, this discrepancy is detected by the steering amount detecting means 8, 9
In order to prevent erroneous determination of the failure of FIG.
When a failure occurs at the instant t1, the failure determination steering angle set value θs is determined so that the failure can be detected at the instant t2 without delay.

Similarly, the turning amount detecting means 12 and 13 for the failure-determining turning angle set value δs in step 50 are also used.
The discrepancy between the detected steering angles δ1 and δ2 due to the difference in the occurrence of the mechanical backlash or the difference in the detection error is not erroneously determined to be the failure of the steering amount detecting means 12 or 13. On the other hand, when a failure occurs at the instant t1 in FIG. 6, the failure determination turning angle setting value δs is determined so that the failure can be detected at the instant t2 without delay.

Next, the turning angle deviation set value Δδs for failure determination in step 54 and the set time TMs for failure determination in step 57 will be considered. Normally, since the shaft clutch 3 is released, there is no mechanical correlation between the steering wheel steering angle θ and the wheel steering angle δ, and the steering wheel steering angle θ is determined by the wheel steering angle δ and the steering wheel steering angle θ. The target steering angle δ0 differs from the target steering angle δ0 due to a response delay even before the instant t1 in FIG. 7 when the steering motor 11 is normal. Therefore step 5
The steering angle deviation set value Δδs for failure determination in No. 4 is set to about the maximum value of this difference. When the turning angle deviation setting value Δδs for failure determination is thus determined, even if the turning motor 11 is normal, the wheel turning angle δ and the target turning angle are obtained as in the periods T1 and T2 before the instant t1 in FIG. The absolute value of the difference from the steering angle δ0 may temporarily exceed the failure determination turning angle deviation set value Δδs. However, when the steering motor 11 is normal, the wheel steering angle δ follows the target steering angle δ0,
The absolute value of the above difference is the turning angle deviation set value Δδs for failure determination.
Is shorter than this time, and is as short as possible within a range not shorter than this time. For example, the failure determination set time T in step 57 is set to a length indicated by T3 in FIG.
Determine Ms. Such a failure determination turning angle deviation set value Δ
According to δs and the failure determination set time TMs, it is possible to prevent erroneous determination of a failure of the steering motor 11 during the periods T1 and T2 in FIG.
2, the failure of the steering motor 11 can be reliably detected.

FIG. 8 shows another embodiment of the present invention. In this embodiment, as shown in steps 45 'and 51' instead of steps 45 and 51 in FIG. Is the steering wheel steering angle θ, the first steering angle detection value δ1 detected by the steering angle sensor 12 is the wheel steering angle δ, and these are used for steering control. Offer. Then, in step 44, the absolute value of the difference between the first steering angle detection value θ1 and the second steering angle detection value θ2 calculated from the steering reaction force motor angle detection value of the encoder 9a is determined as the failure determination steering angle. When the steering amount detecting means 8, 9a is determined to have reached the set value θs, it is checked in an additional step 63 whether the first steering angle detected value θ1 is abnormal (whether the steering angle sensor 8 is defective). If so, steps 46 and 61 are executed to perform the corrected steering of the wheels. In step 63, the second steering angle detection value θ2 is abnormal (encoder 9a) instead of the first steering angle detection value θ1. If it is determined that there is a failure), since this is not used for steering control, there is no shift in the wheel turning position, so that the shaft clutch 3 is engaged in step 62 without performing the corrective steering of the wheels.

At step 50, the first steering angle detection value δ1
And a second steering angle detection value δ2 calculated from the rack stroke detection value of the stroke sensor 13 to determine that the absolute value of the difference has become the failure-determining steering angle setting value δs. In the event of a failure of 12, 13 an additional step 64
It is checked whether the first steering angle detection value δ1 is abnormal (whether the steering angle sensor 12 is malfunctioning) or not, and if so, the steps 52 and 61 are executed to perform the corrective steering of the wheels. If it is determined in step 64 that the second steered angle detection value δ2 is not the first steered angle detected value δ1, but the second steered angle detected value δ2 is abnormal (the stroke sensor 13 is out of order), this is not used for steering control. Since there is no shift in the wheel turning position, the shaft clutch 3 is engaged in step 62 without performing the corrective steering of the wheels.

Note that, contrary to FIG. 8, the second detected steering angle θ calculated from the detected steering reaction motor angle of the encoder 9a.
2 is the steering wheel steering angle θ, the second steering angle detection value δ2 calculated from the rack stroke detection value of the stroke sensor 13 is the wheel steering angle δ, these are used for steering control, and the detection by the steering angle sensor 8 is performed. The first steering angle detection value θ1 which is the value is used for the failure determination of the steering amount detection means 8 and 9a, and the first steering angle detection value δ1 which is the detection value of the turning angle sensor 12 is used as the steering amount detection means. It is needless to say that the same purpose can be applied to achieve the intended purpose also in the case of using the failure judgments 12 and 13.

FIGS. 9 and 10 show still another embodiment of the present invention. In this embodiment, as shown in FIG. 9, the motor clutch 11 of the steering motor 11 shown in FIG.
A steering motor 14 having a built-in motor clutch 14a similar to that of the steering motor 11 is newly provided, and the steering motor 14 is disposed in parallel with the steering motor 11 and is drivingly coupled to the lower steering shaft 1b. In this case, the amount of rotation given by the steering motor 14 to the lower steering shaft 1b is equal to the amount of rotation given by the steering motor 11 to the lower steering shaft 1b, and the sum of the torques of these steering motors 11 and 14 is equal to the lower steering shaft. 1b.

The steering control in the present embodiment is as shown in FIG. 10, and the control content of step 60 in FIG. 4 is changed as in step 60 ′, and the destination of the control is changed from step 62 to step 61. Is changed, and step 65 is added before step 60 '. In step 65, which is selected when the steering motor 11 or 14 is determined to have failed in step 57, the amount of deviation of the wheel steering position due to the failure is determined by the failure determination steering angle deviation set value Δδs and the steering motor rotation speed. And the sum of the failure determination set time TMs and the integrated value.

Next, in step 60 ', the failed motor of the steering motor 11 or 14 is turned off, and the clutch 11a or 1 of the failed motor is turned off.
Release 4a so that the failed motor does not interfere with normal motor operation. Thereafter, control is performed at step 6
In step 62, the steering motor 14 or 11 (normal motor) is reversely rotated to correct and steer the wheels so as to eliminate the displacement in step 65.
To mechanically connect the upper and lower steering shafts 1a and 1b. In the present embodiment, by providing the steering motors 11 and 14 as a set of two, the normal steering motor is used by the control of FIG. 10 and the position of the wheel steering position due to the failure of the steering motor is controlled. After the displacement is eliminated, the upper and lower steering shafts 1a and 1b can be mechanically connected by the shaft clutch 3.

In the case of FIG.
Steps 5 ′ and 51 ′ described in FIG.
And the steps 63 and 64 described above with reference to FIG.
11 is added to the control shown in FIG. 11, the first steering angle detection value θ1 which is the detection value of the steering angle sensor 8 is used as the steering wheel steering angle θ for the steering control, and the detection of the turning angle sensor 12 is performed. The first steering angle detection value δ1, which is a value, is subjected to steering control as a wheel steering angle δ, and when the first steering angle detection value θ1 or the first steering angle detection value δ1 becomes abnormal, The correction steering of the wheel may be performed.

FIGS. 12 and 13 show still another embodiment of the present invention. In this embodiment, as shown in FIG. 12, two steering motors 15 and 16 are provided as one set. Are motor clutches 11a,
No motor clutch such as 14a is built in,
The steering system related to the lower steering shaft 1b is arranged in series as follows. Steering motor 15
Is connected to the lower steering shaft 1b through a non-reciprocal transmission means 15a such as a worm gear which does not rotate the steering motor 15 due to an external force from the lower steering shaft 1b to the steering motor 15. Do. The steering motor 16 is connected to the lower steering shaft 1b.
It is mounted on a rack 18 which is stroked by the upper pinion 17, and the output shaft of the steering motor 16 is drive-coupled to the rack 5. This drive connection is rotated by an external force from the rack 5 to the steering motor 16. The rotation is performed through irreversible transmission means 16a, such as a worm gear, which does not rotate the rudder motor 16. In this case, the rack 18 is stroked by the rotation of the steering motor 15, and the rack 5 is stroked by the rotation of the steering motor 16 that strokes with the rack 18. Therefore, the sum of the rotation amounts of the steering motors 15 and 16 becomes the stroke amount of the rack 5, and the forces generated by the steering motors 15 and 16 are equal to each other and equal to the force acting on the rack 5.

The steering control in the present embodiment is as shown in FIG. 13, and step 60 'in FIG. 10 can be omitted. That is, the failed steering motor 15
Or the control of 16 is not required at all, and the normal steering motor 16 or 15
By simply rotating the shaft clutch 3 in the reverse direction at step 61, the shaft clutch 3 can be engaged at step 62 after correcting the deviation of the wheel steering position due to the failure of the steering motor.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a vehicle steering system according to an embodiment of the present invention.

FIG. 2 is a detailed sectional view of the shaft clutch according to the embodiment.

FIG. 3 is a functional block diagram showing steering control of the steering device according to the embodiment.

FIG. 4 is a flowchart showing a control program when the steering control is executed by a microcomputer.

FIG. 5 is a change time chart of a detection value when a steering angle sensor fails.

FIG. 6 is a change time chart of a detection value when a steering angle sensor fails.

FIG. 7 is a time chart showing a comparison between a wheel turning angle and a target turning angle when a turning motor fails.

FIG. 8 is a flowchart similar to FIG. 4 of a steering control program showing another embodiment of the present invention.

FIG. 9 is a schematic diagram similar to FIG. 1, showing a vehicle steering system according to still another embodiment of the present invention.

FIG. 10 is a flowchart similar to FIG. 4, showing a steering control program to be executed by the microcomputer in the embodiment.

FIG. 11 is a flowchart showing a modified example of the steering control program shown in FIG.

FIG. 12 is a schematic diagram similar to FIG. 1, showing a vehicle steering system according to still another embodiment of the present invention.

FIG. 13 is a flowchart similar to FIG. 4, showing a steering control program to be executed by the microcomputer in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steering shaft 1a Upper steering shaft 1b Lower steering shaft 2 Steering wheel 3 Shaft clutch (disconnection means) 4 Pinion 5 Rack 6 Wheel 7 Tie rod 8 Steering angle sensor (Steering amount detecting means) 9 Steering reaction force motor 9a Encoder (Steering amount) Detecting means) 10 Torque sensor 11 Steering motor 11a Motor clutch 12 Steering angle sensor (steering amount detecting means) 13 Stroke sensor (steering amount detecting means) 14 Steering motor 14a Motor clutch 15 Steering motor 15a Irreversible transmission Means 16a Irreversible transmission means 16 Steering motor 17 Pinion 18 Rack 21 Clutch plate 22 Clutch plate 24 Spring 25 Magnet 26 Coil 31 Steering amount detecting means failure detecting unit 32 Steering amount detecting means failure detecting unit 33 Target steering angle calculating unit 34 Steering motor failure detection unit 35 Motor output calculation unit 36 Steering position deviation elimination unit

Claims (11)

[Claims] 1. A steering amount detecting means for detecting an amount of steering by a steering wheel, and a turning amount detecting means for detecting an actual turning amount of a wheel. Usually, the steering amount and the turning detected by these means are provided. The wheels are steered by a steering motor so that the distances have a predetermined relationship.
A steering apparatus for a vehicle in which a steering wheel and a wheel are mechanically steered by a steering wheel by connecting a steering wheel and a wheel by disconnecting / connecting means when a steering amount detecting means or a steering motor fails, A steering apparatus for a vehicle, characterized in that the wheels are steered to a position corresponding to a steering position of a steering wheel by the steering motor before the wheels are connected to each other by a connecting / disconnecting means. 2. The steering control device according to claim 1, wherein the steering amount detecting means is provided as a pair, and an average value of the detected steering amount is used as a steering amount by a steering wheel for steering control. When the deviation of the set value becomes a set value, it is determined that the steering amount detection means has failed, and after turning the wheel by the turning motor in a direction in which the deviation of the set value is eliminated, the disconnection means A steering apparatus for a vehicle, wherein a steering wheel and a wheel are connected to each other. 3. The steering amount detecting means according to claim 1, wherein said steering amount detecting means is provided as a pair, and one of the detected steering amount values is used as a steering amount by a steering wheel for steering control. When the deviation becomes the set value, it is determined that the steering amount detecting means has failed, and only when it is determined that the steering amount detecting means related to the one steering amount detected value has failed at the time of the failure determination, the steering amount detection value A steering apparatus for a vehicle, wherein the steering wheel is steered by the steering motor in a direction in which the deviation is eliminated, and then the steering wheel is connected to the wheel by the connection / disconnection means. 4. The steering control according to claim 1, wherein the steering amount detecting means is provided as a pair, and an average value of the detected steering amount is used as a steering amount of the wheel. When the deviation between the steering amount detection values reaches a set value, it is determined that the steering amount detection means has failed, and the wheel is turned in a direction in which the deviation corresponding to the set value is eliminated. A steering device for a vehicle, characterized in that the steering wheel and the wheels are connected by the connecting / disconnecting means after the vehicle is turned. 5. The steering control according to claim 1, wherein the steering amount detecting means is provided as a pair, and one of the detected steering amount values is used as a steering amount of a wheel for steering control. When the deviation between the detected values of the turning amount becomes a set value, it is determined that the turning amount detecting means has failed. When the failure is determined, the turning amount detecting means relating to the one turning amount detecting value has failed. Only when it is determined that the steering wheel has been steered by the steering motor in a direction in which the deviation of the set value is eliminated, the steering wheel and the wheel are connected by the connection / disconnection means. A steering device for a vehicle, comprising: 6. The state according to claim 1, wherein a deviation between a target turning amount according to a steering amount by the steering wheel and a turning amount of the wheel is equal to or larger than a set value. A steering apparatus for a vehicle, characterized in that it is configured to determine that the steering motor has failed when the set time has continued. 7. The wheel steering amount shift according to claim 1, wherein the two steering motors are provided as a pair, and when it is determined that the steering motor has failed, the wheel steering amount is shifted due to the failure. A steering apparatus for a vehicle, characterized in that the steering wheel is turned by a normal steering motor so that the steering wheel and the wheel are connected by the connection / disconnection means. 8. The steering motor according to claim 7, wherein the deviation of the wheel steering amount due to the failure of the steering motor is set to the set value relating to the deviation between the target steering amount and the wheel steering amount. A vehicle steering system characterized in that the rotational speed of the vehicle and the integrated value of the set time are obtained by adding. 9. The method according to claim 7, wherein the two
A faulty steering motor is provided in which the steering motors provided as a set are arranged in parallel with the wheel steering system, and both of the steering motors are provided with clutches capable of mechanically connecting and disconnecting the wheel steering system. And turning off the vehicle and disconnecting the vehicle from the wheel steering system by releasing the clutch. 10. The steering motor according to claim 7, wherein the steering motors provided as a pair are arranged in series with a wheel steering system, and do not rotate in response to an input from a wheel. Drive-coupled to the wheel steering system by transmission means,
A steering apparatus for a vehicle, wherein a failed steering motor is turned off. 11. The vehicle steering apparatus according to claim 1, wherein the failure is alarmed.