JP2005335434A - Steering control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a self-diagnosis of a system without giving a driver a sense of incongruity in a steering control device. <P>SOLUTION: A four-wheel steering controller 5 for performing driving control of a rear wheel steering actuator 4, steers rear wheels 12, 12 according to a self-diagnostic rear wheel steering angle command value δ<SB>RMD</SB>unrelated to the traveling state of a vehicle, computed by a self-diagnostic rear wheel steering angle command value computing part 502 at the power on in a predetermined period. The four-wheel steering controller 5 is provided with an abnormality detecting part 505 for determining system abnormality based on deviation between the self-diagnostic rear wheel steering angle command value δ<SB>RMD</SB>and a rear wheel steering angle detection signal δ<SB>R</SB>and lighting a fail lamp 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention belongs to the technical field of steering control devices.

Electronic control systems mounted on vehicles are self-diagnosed using various methods in order to increase the safety of the system. For example, in a conventional brake fluid pressure control device, each time an ignition switch is turned on, a motor or an electromagnetic valve of a brake fluid pressure control actuator is operated and each signal is checked to perform self-diagnosis. In particular, the anti-skid control device does not operate the actuator during normal driving (when the anti-skid control is not performed). Therefore, from the standpoint of preventing sticking of the electromagnetic valve and the like, the anti-skid control device is provided each time the ignition switch is turned on. It is operated (for example, see Patent Documents 1 and 2).
Japanese Patent Laid-Open No. 08-310376 JP 09-323638 A

  In the steering control device, since the actuator is always operating during normal traveling, only the initial operation check is performed at the time of factory production, and the self-diagnosis is not performed every time before starting the control. This operation check is performed by a worker one by one and takes a lot of man-hours, so it is desirable to perform a self-diagnosis.

  However, if the actuator is operated each time the ignition is turned on as in the case of the anti-skid control device, the front wheels or / and the rear wheels are steered, and the behavior is as if the vehicle overcame the saddle, There was a risk that the driver would feel uncomfortable.

  The present invention has been made paying attention to the above problems, and an object of the present invention is to provide a steering control device capable of performing a self-diagnosis of the system without giving the driver a sense of incongruity.

In order to achieve the above object, the present invention provides:
Steering control means for outputting front wheel and / or rear wheel steering angle command values according to the running state of the vehicle;
Steering means for steering front wheels and / or rear wheels according to the steering command value;
Rudder angle detecting means for detecting the rudder angle steered by the steered means;
When the power is turned on during a predetermined period, a self-diagnosis steering command value that is not related to the traveling state of the vehicle is output to the steering means, and based on the self-diagnosis steering command value and the detected steering angle Self-diagnosis means for judging abnormality of the steering means;
It is characterized by providing.

  In the present invention, if the predetermined period for performing the self-diagnosis is a standard period from the factory offline to before the vehicle reaches the user, the system self-diagnosis can be performed without giving the user a sense of incongruity. Can be implemented.

  Hereinafter, the best mode for carrying out the present invention will be described based on the first embodiment.

First, the configuration will be described.
FIG. 1 is a system block diagram of a vehicle to which a steering control device according to a first embodiment is applied. The steering control device according to the first embodiment includes a steering angle sensor 1, a vehicle speed sensor 2, a rear wheel steering angle sensor (rear wheel steering angle sensor). An angle detection means) 3, a rear wheel steering actuator 4, a four wheel steering control controller (rear wheel steering angle control means) 5, an ignition switch 6, and a fail lamp (warning means) 7.

  The steering angle sensor 1 is provided on a column shaft 11 that connects a steering wheel 8 and a rack-and-pinion type front wheel steering mechanism 10 that steers the front wheels 9 and 9, and detects the steering angle of the driver. Output to the four-wheel steering control controller 5.

  The vehicle speed sensor 2 detects the vehicle speed (vehicle speed) using the average value of the output of each wheel speed sensor provided on each of the front wheels 9 and 9 and the rear wheels 12 and 12, and the four-wheel steering control controller. Output to 5. The rear wheel steering angle sensor 3 detects the turning angle (steering angle) of the rear wheels 12 and 12 and outputs it to the four-wheel steering control controller 5.

  The rear wheel steering actuator 4 includes a rack shaft for turning the rear wheels 12 and 12 and a DC motor or the like connected to the rack shaft via a speed reducer, based on a control command from the four-wheel steering control controller 5. Then, the rear wheels 12, 12 are steered.

  The four-wheel steering control controller 5 changes the rear wheel steering angle with respect to the rear wheel steering actuator 4 based on inputs from the steering angle sensor 1, the vehicle speed sensor 2, the rear wheel steering angle sensor 3, and the ignition switch 6. The control command to be output is output.

  Here, the four-wheel steering control controller 5 is set to improve the turning performance by turning the rear wheels 12 and 12 in the opposite phase to the front wheels 9 and 9 when traveling at a low speed. On the other hand, during medium and high speed traveling, the rear wheels 12 and 12 are steered in phase with the front wheels 9 and 9 to improve traveling stability.

  FIG. 2 is a control block diagram of the four-wheel steering controller 5. The four-wheel steering controller 5 includes a control rear wheel steering angle command value calculation unit 501 and a self-diagnosis rear wheel steering angle command value calculation unit 502. A rear wheel steering angle command value selection unit 503, a rear wheel steering angle servo calculation unit 504, and an abnormality detection unit 505.

The control rear wheel steering angle command value calculation unit 501 receives the steering angle detection value θ from the steering angle sensor 1 and the vehicle speed detection value V from the vehicle speed sensor 2, and receives the rear wheel steering angle command value for vehicle motion control. δ _RMC is calculated.

The rear wheel steering angle command value calculation unit 502 for self-diagnosis receives the output of the ignition switch 6 and calculates a rear wheel steering angle command value _δRMD for self-diagnosis set in advance.

The rear wheel steering angle command value selection unit 503 receives the output of the ignition switch 6, the output of the control rear wheel steering angle command value calculation unit 501, and the output of the rear wheel steering angle command value calculation unit 502 for self-diagnosis. The rear wheel steering angle command value δ _RMC for vehicle motion control or the rear wheel steering angle command value δ _RMD for self-diagnosis is selected, and the final rear wheel steering angle command value δ _RM is selected. decide.

The rear wheel steering angle servo calculation unit 504 receives the output of the rear wheel steering angle sensor 3 and the output of the rear wheel steering angle command value selection unit 503, and detects the rear wheel steering angle detected value from the rear wheel steering angle sensor 3. [delta] _R and outputs a control signal so as to match the rear wheel steering angle command value [delta] _RM to the rear wheel steering actuator 4.

Abnormality detecting unit 505, the output of the rear wheel steering angle sensor 3, the output of the rear wheel steering angle command value selecting section 503 are input to the rear wheel steering angle command value [delta] _RM and the rear wheel steering angle detected value [delta] _R Based on this, an abnormality of the steering control device is detected, and a fail lamp lighting signal is output to the fail lamp 7.

Next, the operation will be described.
The control rear wheel rudder angle command value calculation unit 501 calculates the rear wheel rudder angle command value δ _RMC corresponding to each traveling condition. In the first embodiment, a yaw rate reference model type control method will be described as an example of the control method. .

This method is roughly divided into a vehicle motion target value setting unit and a rear wheel steering angle command value calculation unit. First, in the vehicle motion target value setting unit, based on the transfer function between the steering angle detection value θh and the target yaw rate ψ _M ′ shown in the following formula (1), the vehicle motion target value with respect to the steering angle detection value θh As a target yaw rate ψ _M ′.
_{ψ M '/ θh = Gψ'} × {ω n 2 (n 1 s + 1)} / (s 2 + 2ζω n s + ω n 2) ... (1)

In Equation (1), Gψ ′, ω _n , n ₁ and ζ are vehicle speed dependent constants, Gψ ′ is a yaw rate gain, ω _n is a natural angular frequency, n ₁ is a zero equivalent value, and ζ is a damping coefficient. It is. These vehicle speed dependent constants are set based on a control map representing correspondence between preset vehicle speeds and vehicle speed dependent constants.

The vehicle speed dependent constant is the characteristic response of the yaw rate ψ ′ to the change in the detected steering angle θ, the yaw rate gain Gψ ′ specifies the steady gain, that is, the steady yaw rate with respect to the steering angle, and the natural angular frequency ω _n is the vibration frequency. The zero-point equivalent value n ₁ specifies the yaw rate rising speed with respect to the change of the steering angle, that is, the yaw rate rising characteristic, and the attenuation coefficient ζ specifies the convergence speed, that is, the yaw rate convergence. .

Therefore, the vehicle speed dependent constant is set to a value that can be a predetermined response characteristic, and the response characteristic of the target yaw rate ψ _M ′ calculated based on the set vehicle speed dependent constant and the equation (1) is a predetermined response characteristic.

Therefore, by setting the vehicle speed dependent constant according to the vehicle speed, the response characteristic of the target yaw rate ψ _M ′ becomes a response characteristic that varies depending on the vehicle speed, and the yaw rate gain Gψ ′, the natural angular frequency ω _n , and the zero equivalent value By individually changing n ₁ and the damping coefficient ζ, it is possible to obtain response characteristics that differ only in the steady gain or only in the vibration frequency, for example.

Next, the rear wheel rudder angle command value calculator calculates the target yaw rate ψ _M ′ and target yaw angular acceleration ψ _M ″ set by the vehicle motion target value setting unit, the steering angle detection value θ, and the vehicle speed detection value V based on the target yaw rate ψ _M ′. Based on the following equation (2), the rear wheel steering angle that can make the actual yaw rate coincide with the target yaw rate ψ _M ′ is calculated by inverse calculation of the two-degree-of-freedom vehicle motion equation, Wheel steering angle command value δ _RMC .

Here, the target yaw angular acceleration ψ _M ″ can be obtained in the process of calculating the target yaw rate ψ _M ′ based on the equation (1).
_{+ δ RM = β R (V} Y -L R × ψ M ') / V ... (2)
β _R = C _R / K _R
C _R = (L _F × C _F −I _Z × ψ _M "/ 2) / L _R
C _F = eK _F × β _{F
Β F = θh / N- (V} Y + L F × ψ M ') / V
V _Y = ∫V _Y 'dt
V _Y = (2C _F + 2C _R ) / MV−ψ × _M ′

In equation (2), V _Y is the vehicle lateral velocity, β _F is the front wheel side slip angle, β _R is the rear wheel side slip angle, L _F is the distance from the front axle to the vehicle center of gravity, and L _R is the vehicle from the rear axle. distance to the center of gravity, C _F is the front wheel cornering force, C _R is the rear wheel cornering force, K _R is the cornering power of the rear wheels of the vehicle, eK _F is front equivalent cornering power (front wheel cornering power of the vehicle There is also a value that takes into account the decrease in cornering power with respect to the steering angle due to the effect of steering rigidity), I _z represents the yaw moment of inertia of the vehicle, M represents the mass of the vehicle, and N represents the steering gear ratio.

The self-diagnosis rear wheel rudder angle command value calculation unit 502 uses the self-diagnosis rear wheel rudder angle command value as the rear wheel steering pattern not related to the steering angle and the vehicle speed when the self-diagnosis is performed when the ignition switch is turned on. Output as _δRMD . The rear wheel turning pattern for self-diagnosis will be described later.

The rear wheel steering angle command value selection unit 503 uses either the control rear wheel steering angle command value δ _RMC or the self-diagnosis rear wheel steering angle command value δ _RMD based on the operation information of the ignition switch and the self-diagnosis information. And the final rear wheel steering angle command value _δRM is determined. Detailed processing contents at this time will be described later.

In the rear wheel steering angle servo calculating section 504, a rear wheel steering angle command value [delta] _RM after obtaining in the rear wheel steering angle command value selecting unit 503, the wheel steering angle detection signal [delta] _R after the rear wheel steering angle sensor 3 A control signal that eliminates the deviation is calculated by servo calculation and output to the rear wheel steering actuator 4. As described above, for example, a robust model matching control method is used for the servo calculation.

The abnormality detection unit 505, from the relationship between the rear wheel steering angle command value [delta] _RM and the rear wheel steering angle detected value [delta] _R, it is determined whether the steering control apparatus is operating normally. As an example of the determination method, when the state deviation between the rear wheel steering angle command value [delta] _RM and the rear wheel steering angle detected value [delta] _R is greater than a predetermined value continues for a predetermined time, it is determined that the abnormality of the steering control apparatus. Here, although the predetermined value and the predetermined time vary depending on the ability of the rear wheel steering actuator, for example, the predetermined value is set to 0.05 ° and the predetermined time is about 1.0 second. When it is determined that the steering control device is abnormal, a fail lamp lighting signal is output to light the fail lamp 7.

[Fault diagnosis process at factory shipment]
FIG. 3 is a flowchart showing the flow of a failure diagnosis process for a worker at the time of factory shipment. Each step will be described below.

  In step S1, the four-wheel steering controller 5 is attached, and the process proceeds to step S2.

  In step S2, a self-diagnosis operation is performed by turning on the ignition switch 6, and the process proceeds to step S3. In the past, an engineer checked the operation of the four-wheel steering control system using a measuring device for checking one by one, but in Example 1, the engineer simply turned on the ignition switch 6 and self- Since the operation check is performed by diagnosis, the man-hours can be greatly reduced.

  In step S3, the worker checks the state of the fail lamp 7. If the fail lamp 7 is extinguished, it is determined that the operation is normal, and the process proceeds to step S4. If the fail lamp 7 is lit, the operation is abnormal, and thus the process proceeds to step S6.

  In step S4, the collective history is deleted by the fault diagnosis machine including other systems, and the process proceeds to step S5. This is to erase the failure history of each system that occurs during the installation and inspection process in the factory, and is performed before shipment for the purpose of erasing unnecessary history information for each normally operating system. Is done.

  In step S5, the product is shipped to the next process.

  In step S6, since the four-wheel steering control system is abnormal, countermeasures are taken when the abnormality occurs. For example, the connection connector of the four-wheel steering control controller 5 is confirmed, and the four-wheel steering control controller 5 is exchanged. When such a countermeasure is implemented, the process of step S1 or step S2 is repeated again.

[Power-on processing]
FIG. 4 is a flowchart showing the flow of the four-wheel steering control pre-processing executed by the four-wheel steering control controller 5 when the ignition switch is turned on (when the power is turned on). Each step will be described below.

  In step S11, variables related to self-diagnosis recorded in the nonvolatile memory are read out, and the process proceeds to step S12.

  In step S12, in order to count the number of times the ignition switch is turned on, a counter for counting the number of times the ignition switch is turned on is counted up, the result is recorded in the nonvolatile memory, and the process proceeds to step S13.

  In step S13, a periodic interrupt is set, and a state of waiting for an interrupt operation repeated every predetermined time is entered. Although the predetermined time varies depending on the system, a typical value of the traveling control system is about 5 ms to 10 ms.

[4-wheel steering control processing]
FIG. 5 is a flowchart showing the flow of the four-wheel steering control process executed by the four-wheel steering control controller 5.

In FIG. 5, in step S21, values of the steering angle θ, the vehicle speed V, and the rear wheel steering angle δ _R are read based on the sensor signals, and the process proceeds to step S22.

  In step S22, in order to integrate the ignition switch ON time, the ignition switch ON time integration counter is counted up, the result is recorded in the nonvolatile memory, and the process proceeds to step S23.

In step S23, the control rear wheel steering angle command value _ΔRMC is calculated, and the process proceeds to step S24. The control rear wheel steering angle command value δ _RMC is calculated based on the steering angle θ and the vehicle speed V, as described above with reference to the control rear wheel steering angle command value calculation unit 501 in FIG.

In step S24, a self-diagnosis rear wheel steering angle command value _ΔRMD is calculated, and the process proceeds to step S25. Here, the self-diagnosis rear wheel steering angle command value _δRMD is calculated in a predetermined pattern regardless of the steering angle and the vehicle speed. For example, as shown in FIG. 7, the rear wheel steering angle operates relatively large, such as a command value that gradually changes from the neutral position by 0.5 ° to the left or right, or a sin-wave command value as shown in FIG. Pattern.

  In step S25, the reception state of the history erasure signal is checked. Here, as described above, the reception state of the history erasure signal transmitted by the collective history erasure operation by the failure diagnosing device performed in step S4 of FIG. 3 is confirmed. If a history deletion signal has been received, the process proceeds to step S26, and if not received, the process proceeds to step S29.

  In step S26, the self-diagnosis end flag is set, and the result is recorded in the nonvolatile memory, and the process proceeds to step S27.

  In step S27, the state of the fail lamp 7 is checked. If the fail lamp 7 is lit, the process proceeds to step S29. If the fail lamp 7 is not lit, the process proceeds to step S28.

  In step S28, since the system is operating normally, a failure history erasing process is performed, and the process proceeds to step S29.

  That is, when the history erasure signal is received in the operations from step S26 to step S28, the self-diagnosis end flag is set regardless of the operation state of the system, and the subsequent self-diagnosis operation is not performed. In addition, even if the collective history erasure operation is performed by the engineer in a state where the system is not operating normally, the failure history erasure process is not performed and the failure history remains because the fail lamp 7 is lit. .

In step S29, the state of the self-diagnosis end flag is checked. If the self-diagnosis end flag is set, the process proceeds to step S34, and if it is not set, the process proceeds to step S30. Thus, after the self-diagnosis flag is set, the self-diagnosis rear wheel steering angle command value _δRMD is not output, and only the control rear wheel steering angle command value _δRMC is output.

In step S30, the state of the vehicle speed V is checked. If the vehicle speed V is zero, that is, the vehicle is stopped, the process proceeds to step S31. If the vehicle speed V is not zero, the process proceeds to step S34. Although it is not possible in principle, if the rear wheel steering angle command value δ _RMD for self-diagnosis is output during driving, the vehicle behavior may change suddenly. The program structure.

  In step S31, the number of ignition switch ON operations recorded in the nonvolatile memory in step S12 of FIG. 4 is checked. If the number of times the ignition switch is turned on is smaller than 4, the process proceeds to step S32, and if it is 4 times or more, the process proceeds to step S34.

  In step S32, the accumulated time of the ignition switch ON operation is checked. When the ignition switch ON integration time is less than 60 minutes, the process proceeds to step S35, and when it is 60 minutes or more, the process proceeds to step S33.

  In step S33, the self-diagnosis end flag is set, and the result is recorded in the nonvolatile memory, and the process proceeds to step S34.

  In step S31 and step S32, the number of times the ignition switch is turned on is set to 4 times, and the integration time is set to 60 minutes. This is a value that the self-diagnosis will have completed if this number of times and time are sufficient. In other words, the self-diagnosis that is not OK after these times and time should not be shipped, but even if it is shipped, the self-diagnosis end flag is set. It is possible to prevent the self-diagnosis operation from being performed after the self-diagnosis operation is not performed.

In step S34, since not performed self-diagnosis, the normal control rear wheel steering angle command value [delta] _RMC calculated in step S23 is outputted as a [delta] _RM, the process proceeds to step S36.

In step S35, for carrying out the self-diagnosis, the wheel steering angle command value [delta] _RMD after a self-diagnosis calculated in step S24 is outputted as a [delta] _RM, the process proceeds to step S36.

At step S36, the wheel steering angle command value [delta] _RM after being calculated in step S34 or step S35, a control signal to eliminate the deviation between the wheel steering angle detection signal [delta] _R after the rear wheel steering angle sensor 3 Servo It is calculated by calculation and output to the rear wheel steering actuator 4, and the process proceeds to step S37. For servo computation, for example, a robust model matching control method is used.

  In step S37, the system abnormality detection control process is executed, and the process proceeds to return. Details of the abnormality detection control process are shown in FIG.

[Abnormality detection control processing]
FIG. 6 is a flowchart showing a flow of abnormality detection control processing executed by the four-wheel steering control controller 5.

At step S41, and calculates a deviation δerr between the rear wheel steering angle detection signal [delta] _R and the rear wheel steering angle command value [delta] _RM, the process proceeds to step S42.

  In step S42, the absolute value of the deviation Δerr is compared with 0.05 °. If the absolute value of the deviation Δerr is smaller than 0.05 °, the process proceeds to step S46, and if the absolute value of the deviation Δerr is 0.05 ° or more, the process proceeds to step S43.

  In step S43, ERR_timer that counts the time when the absolute value of deviation Δerr is 0.05 ° or more is counted up, and the process proceeds to step S44.

  In step S44, ERR_timer is compared with 1.0 second. If ERR_timer is greater than 1.0 seconds, the process proceeds to step S45, and if ERR_timer is 1.0 or less, the process proceeds to step S47.

  In step S45, since the state where the absolute value of the deviation δerr is 0.05 ° or more exceeds 1.0 second, it is determined that the system is abnormal, and the fail lamp 7 is turned on. The result is recorded in the nonvolatile memory as a failure history, and the process proceeds to return.

  In step S46, since the absolute value of the deviation Δerr is smaller than 0.05 °, ERR_timer is cleared, and the process proceeds to step S47.

In step S47, it is checked whether the rear wheel steering angle command value _δRMD for self-diagnosis is being output. If the rear wheel steering angle command value _ΔRMD for self-diagnosis is being output, the process proceeds to step S48, and if it is not being output, the process proceeds to return to end the processing in the current control cycle.

In step S48, it is checked whether or not the output of the self-diagnosis rear wheel steering angle command value _δRMD has been completed. When the output of the rear wheel steering angle command value _ΔRMD for self-diagnosis is completed, the process proceeds to step S49, and when the output is not completed, the process proceeds to return and the process in the current control cycle is terminated.

  In step S49, since the normality of the system can be confirmed by the self-diagnosis, the self-diagnosis end flag is set, the result is recorded in the nonvolatile memory, and the process proceeds to return.

Note that these abnormality detection processes can detect not only during the self-diagnosis but also the system abnormality during the output of the normal control rear wheel steering angle command value _δRMC . When the system is abnormal during normal control, the failure of the system is notified by turning on the fail lamp 7 without operating the self-diagnosis end flag.

  As described above, a self-diagnosis is performed when the ignition switch is turned on during factory production, and if the system operates normally, a program configuration that does not perform a self-diagnosis when the ignition switch is turned on after that makes the user feel uncomfortable. It is possible to significantly reduce the number of man-hours at the factory without giving it.

  In addition, even if the system is shipped in an abnormal state, the program configuration prohibits self-diagnosis when the ignition switch is turned on, depending on conditions such as the number of times the ignition switch is turned on and the time. Since the self-diagnosis operation after the vehicle has crossed is not performed, there is no possibility of giving the user a sense of incongruity.

Next, the effect will be described.
In the steering control device of the first embodiment, the effects listed below can be obtained.

(1) and 4-wheel steering controller 5 for outputting a wheel steering angle command value [delta] _RM after according to the running state of the vehicle, after steers the rear wheels 12, 12 in accordance with the rear wheel steering angle command value [delta] _RM The wheel steering actuator 4, the rear wheel steering angle sensor 3 that detects the steering angle of the steered rear wheels 12, 12, and the rear wheel steering actuator 4 when the ignition switch 6 is turned ON during a predetermined period. On the other hand, the rear wheel steering angle command value δ _RMD for self-diagnosis regardless of the running state of the vehicle is output, and four-wheel steering is performed based on the rear wheel steering angle command value δ _RM and the rear wheel steering angle detection signal δ _R. Since it has an abnormality detection unit 505 for determining an abnormality of the control system, the engineer can perform an operation check by self-diagnosis only by turning on the ignition switch 6, and the man-hour can be reduced as compared with the conventional operation check. A dedicated measuring device is no longer required, It can be reduced. Moreover, if the predetermined period is a standard time from the factory offline to before the vehicle reaches the user, the system self-diagnosis can be performed without giving the user a sense of incongruity.

  (2) When the abnormality detection unit 505 diagnoses that the system is normal, the abnormality detection unit 505 does not perform the subsequent self-diagnosis, so the probability that the self-diagnosis is performed when the vehicle reaches the user's hand can be further reduced. .

  (3) The abnormality detection unit 505 does not perform a self-diagnosis when the ignition switch is turned on after the ignition switch is turned on. Therefore, the self-diagnosis is performed when the vehicle reaches the user's hand. The probability of being lost can be further reduced.

  (4) The abnormality detection unit 505 does not perform self-diagnosis when the ignition switch is turned on until the accumulated time of the ignition switch reaches 60 minutes. Can be further reduced.

  (5) Since the abnormality detection unit 505 performs self-diagnosis when the vehicle speed V is zero, even if the self-diagnosis is performed after the vehicle has passed to the user, the driver's expectation It is possible to prevent unexpected vehicle behavior from occurring.

  (6) The abnormality detection unit 505 does not perform a self-diagnosis when the ignition switch is turned on after the failure history erasing signal is received from the failure diagnosis machine. The probability of being implemented can be further reduced.

(Other examples)
Although the best mode for carrying out the present invention has been described based on the first embodiment, the specific configuration of the present invention is not limited to the first embodiment and does not depart from the gist of the present invention. Such design changes are included in the present invention.

  In the first embodiment, the four-wheel steering control device that controls the rear wheel steering angle is shown, but the present invention can also be applied to other devices that control the front wheels and the front and rear wheels.

  In the first embodiment, the predetermined time is set to a case where the number of times the ignition switch is turned on is 4 times or more and the accumulated time is 60 minutes or more, and the determination of the system abnormality is continued for 0.05 seconds with a deviation of 0.05 °. For example, the predetermined time may be a time when the self-diagnosis is expected to be completed.

1 is a system block diagram of a vehicle to which a steering control device of Embodiment 1 is applied. 3 is a control block diagram of a four-wheel steering control controller 5. FIG. It is a flowchart which shows the flow of a failure diagnosis process of a worker at the time of factory shipment. 4 is a flowchart showing a flow of pre-processing for four-wheel steering control that is executed by the four-wheel steering control controller 5 when an ignition switch is ON (when power is turned on). 4 is a flowchart showing a flow of a four-wheel steering control process executed by a four-wheel steering control controller 5; 4 is a flowchart showing a flow of abnormality detection control processing executed by a four-wheel steering control controller 5. It is a figure which shows an example (trapezoid wave output) of the output pattern of the rear-wheel steering angle command value for self-diagnosis. It is a figure which shows an example (sin wave output) of the output pattern of the rear-wheel steering angle command value for self-diagnosis.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steering angle sensor 2 Vehicle speed sensor 3 Rear wheel steering angle sensor 4 Rear wheel steering actuator 5 Four wheel steering control controller 501 Rear wheel steering angle command value calculation unit 502 for control Rear wheel steering angle command value calculation unit 503 Rear wheel Steering angle command value selection unit 504 Rear wheel steering angle servo calculation unit 505 Abnormality detection unit 6 Ignition switch 7 Fail lamp 8 Steering wheel 9 Front wheel 10 Front wheel steering mechanism 11 Column shaft 12 Rear wheel

Claims (6)

Steering control means for outputting front wheel and / or rear wheel steering angle command values according to the running state of the vehicle;
Steering means for steering front wheels and / or rear wheels according to the steering command value;
Rudder angle detecting means for detecting the rudder angle steered by the steered means;
When the power is turned on during a predetermined period, a self-diagnosis steering command value that is not related to the traveling state of the vehicle is output to the steering means, and based on the self-diagnosis steering command value and the detected steering angle Self-diagnosis means for judging abnormality of the steering means;
A steering control device comprising: The steering control device according to claim 1, wherein
The steering control device according to claim 1, wherein after the self-diagnosis means is determined to be normal, the steering control device does not determine whether the steering means is abnormal when the power is turned on. In the steering control device according to claim 1 or 2,
The self-diagnosis means stores the number of times the power is turned on, and after the number of times exceeds a predetermined number, the steering control is characterized in that, when the power is turned on, the abnormality of the steering means is not determined. apparatus. The steering control device according to any one of claims 1 to 3,
The self-diagnosis means accumulates and stores the time of power-on since the first power-on, and after the accumulated time exceeds a predetermined time, determines the abnormality of the steering means when the power is turned on. The steering control device characterized by not implementing. In the steering control device according to any one of claims 1 to 4,
The self-diagnosis means judges an abnormality of the steering means when the vehicle is stopped. The steering control device according to any one of claims 1 to 5,
It is connected to an external failure diagnosis device and has communication means for communicating information.
The self-diagnostic means does not carry out the determination of the abnormality of the steering means when the power is turned on after receiving the failure history erasure signal from the external failure diagnosis device.

Images