JP4014817B2 - Vehicle steering control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle steering control device.
[0002]
[Prior art]
Conventionally, for example, a driving signal for assisting a driver's steering with respect to a motor that drives a steering mechanism that steers a steering wheel of a vehicle, such as a vehicle steering device disclosed in Japanese Patent Application Laid-Open No. 11-78948. An EPS (electric power steering system) control device (steering force assist control device) that gives power, and a SAS (steering assist system) control device (automatic steering control device) that gives a drive signal so that the vehicle travels along the travel target; There is known a vehicle steering device that reduces the burden on the driver by assisting the driver's steering while preventing the vehicle from deviating from a predetermined traveling region.
In this vehicle steering device, the assist amount of the steering torque is calculated by the automatic steering control device so that the vehicle travels along the road dividing line on the road, and the assist amount of the steering torque is calculated by the steering force assist control device. Has been entered. The steering force assist control device outputs a drive signal for causing the motor to generate an assist amount of the input steering torque.
[0003]
[Problems to be solved by the invention]
By the way, in the vehicle steering apparatus according to the above prior art, even when the driver consciously performs steering, for example, even when the steering torque input from the driver exceeds a predetermined value, automatic steering is performed. A steering request signal is output from the control device to the steering force assist control device, and the driver feels uncomfortable depending on the traveling state of the vehicle, or the steering request signal output from the automatic steering control device is There is a risk of interference with steering.
The present invention has been made in view of the above circumstances, and prevents the assist of the steering torque required from the automatic steering control device from interfering with the steering of the driver, and accurately reflects the will of the driver. An object of the present invention is to provide a vehicle steering control device capable of performing steering control.
[0004]
[Means for Solving the Problems]
In order to solve the above problems and achieve the object, a vehicle steering control device according to a first aspect of the present invention includes a vehicle steering wheel (for example, steering wheels 19 and 19 in the embodiments described later). A steering mechanism for steering the steered wheels (for example, a manual steering force generating mechanism 16 in an embodiment described later), an actuator for driving the steering mechanism (for example, a motor 20 in an embodiment described later), a driver's Steering force assist control means (for example, an EPS control device 24 in an embodiment to be described later) for supplying a drive signal to the actuator so as to assist steering, and the actuator so that the vehicle travels along a travel target. A vehicle steering control device including automatic steering control means (for example, a SAS control device 23 in an embodiment to be described later) for providing a driving signal. I, the automatic steering control means, the steering force steering force assist mode for driving and controlling the actuator by the assist control means (e.g., EPS control mode in the embodiment described below) sometimes depending on the drive signal for the actuator The torque command value is set to zero, and the torque command value corresponding to the drive signal by the automatic steering control means becomes a value other than zero during the drive control of the actuator in the steering force assist mode. And a failure determination means (for example, step S10 in an embodiment described later) for determining that the automatic steering control means has failed.
[0005]
According to the vehicle steering control device configured as described above, the automatic steering control means stops outputting the drive signal to the actuator in the steering force assist mode in which the actuator is driven and controlled by the steering force assist control means. That is, for example, when the steering torque related to the driver's steering exceeds a predetermined value, when the actuator is driven and controlled by the steering force assist control means so as to assist the driver's steering, The output of the drive signal from the automatic steering control means to the actuator is stopped, and the driver's steering is given priority. Thereby, for example, when the driver's steering intention is clear, it is possible to prevent the steering related to the control of the automatic steering control means from interfering with the driver's steering.
In addition, when the output of the drive signal from the automatic steering control means to the actuator does not stop, it can be determined that the automatic steering control means is in an abnormal state on the steering force assist control means side. Failure determination can be easily performed without the need to provide special detection means for detecting abnormality of the control means.
[0006]
Furthermore, in the vehicle steering control device according to the second aspect of the present invention, the failure determination means is required to set the torque command value corresponding to the drive signal of the automatic steering control means to zero. When the torque command value becomes a value other than zero for a predetermined time or more after the operation, it is determined that the automatic steering control means has failed.
[0007]
According to the vehicle steering control apparatus having the above-described configuration, in addition to the operation and effect related to the present invention described in claim 1, the automatic steering control means has failed if the output of the drive signal does not stop within a predetermined time. Since the determination is made, the failure determination can be performed more accurately.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a vehicle steering control device according to an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a vehicle steering control apparatus 10 according to an embodiment of the present invention.
[0009]
As shown in FIG. 1, in this vehicle steering control device 10, a steering shaft 12 provided integrally with a steering wheel 11 is placed in a steering gear box 14 via a connecting shaft 13 having universal joints 13a and 13b. A manual steering force generating mechanism 16 is configured by being connected to a pinion 15 a of the provided rack and pinion mechanism 15.
The pinion 15a meshes with the rack teeth 17a of the rack shaft 7, and the rotational motion input from the steering wheel 11 is converted into the reciprocating motion of the rack shaft 17 via the pinion 15a. , 18 to steer the two steered wheels 19, 19 connected to each other.
[0010]
A motor 20 is disposed coaxially with the rack shaft 17, and the rotational force of the motor 20 is converted into thrust through a ball screw mechanism 21 provided substantially parallel to the rack shaft 17. That is, a drive side helical gear 20 a is integrally provided on the rotor (not shown) of the motor 20, and the drive side helical gear 20 a is integrally provided at the shaft end of the screw shaft 21 a of the ball screw mechanism 21. Is engaged.
The steering gear box 14 is provided with a torque sensor 22 for detecting the steering torque acting on the pinion 15a. The detection signal of the steering torque detected by the torque sensor 22 is the SAS controller 23 and the EPS. It is input to the control device 24.
[0011]
A SAS (steering assist system) control device 23 calculates the assist amount of the steering torque required to drive the vehicle along the travel line on the road in the vehicle traveling direction as the SAS control mode. Then, under a predetermined condition to be described later, a torque command for outputting the steering torque assist amount to the motor 20 is output to the EPS control device 24, or the output of the torque command is stopped.
For this reason, in addition to the steering torque detection signal output from the torque sensor 22, the SAS control device 23 is provided integrally with a room mirror (not shown) inside the front window of the vehicle, for example, and is provided in front of the vehicle. A signal of image data output from a camera 25 that captures a travel division line in a region, a detection signal output from a yaw rate sensor 26 that detects a yaw rate (rotational angular velocity) about the vertical (gravity) axis of the center of gravity of the vehicle, A detection signal output from a rudder angle sensor 27 that detects the direction and magnitude of the steering angle input by the driver, such as a rotary encoder provided on the steering shaft 12, is input.
[0012]
Further, the SAS control device 23 outputs a signal for notifying ON / OFF of a turn signal output from the turn signal SW28, a signal for notifying ON / OFF of a brake output from the brake SW29, and a wiper SW30. A signal for notifying ON / OFF of the wiper and a signal for notifying operation / stop of the SAS control device 23 output from the main SW 31 are input.
That is, the SAS control device 23 receives, for example, a signal that notifies the turn signal ON from the turn signal SW28, a signal that notifies the brake ON signal from the brake SW29, or the wiper. When a signal notifying that the wiper is turned ON is input from the SW 30, or when a signal notifying that the SAS control device 23 is stopped is input from the main SW 31, or when the travel division line is extracted by the SAS control device 23 When processing is difficult, etc., the output of the torque command to the EPS control device 24 is set to be stopped.
[0013]
Further, as will be described later, the SAS controller 23 determines that the torque Tq detected by the torque sensor 22 in a predetermined state in the SAS control mode is a predetermined torque value #Tq (for example, 20 × 9.80665 × 10 ^−2). If it exceeds N · m), the torque command output to the EPS control device 24 is set to zero.
[0014]
The EPS control device 24 outputs a motor drive current for causing the motor 20 to output an assist amount of steering torque corresponding to the traveling state of the vehicle as an EPS control mode.
For this reason, in addition to the steering torque detection signal output from the torque sensor 22, the EPS control device 24 detects the vehicle movement distance, that is, the vehicle speed for each predetermined unit processing time based on, for example, the rotational speed of the wheels. The detection signal output from the vehicle speed sensor 32, the detection signal output from the motor current sensor 33 that detects the energization current of the motor 20, and the detection signal output from the motor voltage sensor 34 that detects the energization voltage of the motor 20 And are entered.
Further, as will be described later, when the torque Tq detected by the torque sensor 22 is less than or equal to a predetermined torque value #Tq, the EPS control device 24 shifts to the SAS control mode and performs SAS control. The motor drive current corresponding to the torque command input from the device 23 is output to the motor 20. On the other hand, when the predetermined condition is not satisfied, for example, when the torque Tq detected by the torque sensor 22 exceeds the predetermined torque value #Tq, the torque is input to the SAS control device 23 by shifting to the EPS control mode. Ignore the directive.
[0015]
Further, as will be described later, the EPS control device 24 receives an input from the SAS control device 23 when a predetermined state in the SAS control mode, for example, when the torque Tq detected by the torque sensor 22 exceeds a predetermined torque value #Tq. It is determined whether the torque command to be executed is zero, and if this determination result is “NO”, that is, if the torque command is not zero, it is determined that the SAS control device 23 is in an abnormal state, and SAS control is performed. Receiving the torque command input from the device 23 is rejected, and the process proceeds to the EPS control mode.
[0016]
The vehicle steering control apparatus 10 according to the present embodiment has the above-described configuration. Next, the operation of the vehicle steering control apparatus 10 will be described with reference to the accompanying drawings. FIG. 2 is a flowchart showing the operation of the vehicle steering control device 10, and FIG. 3 is a graph showing an example of the time change of the SAS signal (torque command) output from the SAS control device 23 to the EPS control device 24. FIG. 4 is a graph showing an example of the time change of the steering torque detected by the torque sensor 22.
[0017]
First, in step S01 shown in FIG. 2, it is determined whether or not the SAS control device 23 is abnormal.
If this determination is “NO”, the flow proceeds to step S 02.
On the other hand, if this determination is “YES”, the flow proceeds to step S 03, the EPS control mode is entered, and the series of processes is terminated.
[0018]
In step S02, it is determined whether or not the SAS control mode is set.
If this determination is “NO”, the flow proceeds to step S 03. On the other hand, if this determination is “YES”, the flow proceeds to step S 04.
In step S04, it is determined whether or not the steering torque Tq detected by the torque sensor 22 is greater than a predetermined torque value #Tq.
If this determination is “YES”, the flow proceeds to step S 07 described later.
On the other hand, if this determination is “NO”, the flow proceeds to step S 05, and the counter value N is set to zero. Then, the process proceeds to step S06, shifts to the SAS control mode, and a series of processing ends.
[0019]
In step S07, it is determined whether or not the SAS output, that is, the torque command output from the SAS control device 23 to the EPS control device 24 is zero.
If this determination is “NO”, the flow proceeds to step S 06. On the other hand, if the determination is “YES”, the flow proceeds to step S08.
In step S08, a value obtained by adding “1” to the count value N of the counter is set as a new count value N.
[0020]
In step S09, it is determined whether or not the count value N of the counter is equal to or greater than a predetermined count value #N (for example, # N = 20).
If this determination is “NO”, the flow proceeds to step S 06. On the other hand, if the determination is “YES”, the flow proceeds to step S10.
In step S10, it is determined that the SAS control device 23 is in an abnormal state due to a failure or the like, and the EPS control device 24 is set to reject the reception of the torque command input from the SAS control device 23. Proceeding to S03, the series of processing is terminated.
[0021]
That is, in the SAS control mode in which the vehicle is controlled by the SAS control device 23 to travel along a travel line on the road, for example, in order to avoid an obstacle on the road, the driver can perform a predetermined torque. When a steering torque larger than the value #Tq is input via the steering wheel 11, the SAS control device 23 sets the torque command input to the EPS control device 24 to zero. Thereby, although it is SAS control mode, it will be in the state which shifted to EPS control mode in a pseudo manner.
Here, the state in which the torque command input from the SAS control device 23 to the EPS control device 24 is a value other than zero is over a predetermined time until the count value N of the counter becomes a predetermined count value #N or more. If the operation continues, the SAS control mode is shifted to the EPS control mode.
[0022]
For example, when the torque Tq detected by the torque sensor 22 is smaller than a predetermined torque value #Tq as shown by a solid line Tq1 shown in FIG. 4, for example, as shown by a solid line S1 shown in FIG. A SAS signal having a value smaller than a predetermined SAS signal (torque command) #S corresponding to Tq is output from the SAS control device 23 to the EPS control device 24.
In this case, for example, as shown in a graph showing the control ratio between the SAS control mode and the EPS control mode that change in accordance with the torque shown in FIG. 5, the torque Tq detected by the torque sensor 22 is a predetermined torque value. When the torque value is smaller than a predetermined torque value # Tq1 smaller than #Tq, the EPS control mode control ratio is set to zero and the SAS control mode control ratio is set to 100%.
In FIGS. 3, 4, and 5, the torque in each direction is shown with one of the steering angle directions being “right” and the other being “left”.
[0023]
On the other hand, when the torque Tq detected by the torque sensor 22 exceeds a predetermined torque value #Tq as indicated by a broken line Tq2 shown in FIG. 4, for example, a period from time t1 to time t2 shown in FIG. During the period from t3 to time t4, the output of the SAS signal (broken line S2 in FIG. 3) exceeding the predetermined SAS signal #S corresponding to the predetermined torque value #Tq is stopped, for example, in FIG. As shown by the thick solid line S3, the SAS signal (torque command) is set to zero.
[0024]
As described above, according to the vehicle steering control device 10 according to the present embodiment, the SAS control device 23 is the EPS control device 24 when the torque Tq detected by the torque sensor 22 exceeds the predetermined torque value #Tq. Since the torque command received at the EPS control device 24 is a value other than zero, the SAS control device 23 is in an abnormal state such as a failure. It can be determined that That is, an abnormality occurring in the SAS control device 23 can be detected on the EPS control device 24 side. For example, it is not necessary to provide a new detection device for detecting an abnormality in the SAS control device 23, and the vehicle steering control is performed. The cost required for constructing the device 10 can be reduced.
[0025]
In addition, when steering of a predetermined magnitude is performed by the driver's will, such as when the torque Tq detected by the torque sensor 22 exceeds the predetermined torque value #Tq, the EPS control device 24 simply In addition to ignoring the torque command input from the SAS control device 23, the torque command output from the SAS control device 23 to the EPS control device 24 is set to zero, which interferes with the driver's steering. Inappropriate steering control can be reliably prevented.
[0026]
In the above-described embodiment, when the torque Tq detected by the torque sensor 22 exceeds the predetermined torque value #Tq, the torque command output from the SAS control device 23 to the EPS control device 24 is zero. In this case, the output of the torque command from the SAS control device 23 to the EPS control device 24 may be stopped, or the torque command from the SAS control device 23 to the EPS control device 24 may be zero. May be output.
[0027]
In the present embodiment described above, the state in which the torque command input from the SAS control device 23 to the EPS control device 24 is a value other than zero indicates that the counter count value N is equal to or greater than the predetermined count value #N. When it has continued for a predetermined time or more until it becomes, it is assumed to shift from the SAS control mode to the EPS control mode. However, the present invention is not limited to this. For example, step S05, step S08, and step S09 described above are omitted. The SAS control mode may be immediately shifted to the EPS control mode when the torque command input from the SAS control device 23 to the EPS control device 24 becomes a value other than zero.
[0028]
【The invention's effect】
As described above, according to the vehicle steering control apparatus of the first aspect of the present invention, for example, when the driver's steering intention is clear, the steering related to the control of the automatic steering control means is the steering of the driver. Can be prevented. Moreover, on the side of the steering force assist control means, it can be determined that the automatic steering control means is in an abnormal state. For example, there is no need to provide a special detection means for detecting an abnormality in the automatic steering control means. Failure determination can be performed.
Furthermore, according to the vehicle steering control device of the present invention, it is determined that the automatic steering control means has failed when the output of the drive signal does not stop within a predetermined time. It is possible to make a failure determination.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a vehicle steering control device according to an embodiment of the present invention.
FIG. 2 is a flowchart showing an operation of the vehicle steering control device shown in FIG. 1;
FIG. 3 is a graph showing an example of a time change of a SAS signal (torque command) output from the SAS control device shown in FIG. 1 to the EPS control device.
4 is a graph showing an example of a temporal change in steering torque detected by a torque sensor shown in FIG.
FIG. 5 is a graph showing a control ratio between a SAS control mode and an EPS control mode that change according to torque.
[Explanation of symbols]
10 Vehicle Steering Control Device 16 Steering Mechanism (Manual Steering Force Generation Mechanism)
19 Steering wheel 20 Motor (actuator)
23 SAS control device (automatic steering control means)
24 EPS control device (steering force assist control means)
Step S10 Failure determination means

Claims (2)

A steering wheel of a vehicle and a steering mechanism for steering the steering wheel;
An actuator for driving the steering mechanism;
Steering force assist control means for providing a drive signal to the actuator so as to assist the driver's steering;
A vehicle steering control device comprising automatic steering control means for providing a drive signal to the actuator so that the vehicle travels along a travel target,
The automatic steering control means sets a torque command value corresponding to the drive signal to the actuator to zero in a steering force assist mode in which the actuator is driven and controlled by the steering force assist control means,
At the time of driving control of the actuator in the steering force assist mode, it is determined that the automatic steering control unit has failed when the torque command value corresponding to the driving signal by the automatic steering control unit is a value other than zero. A vehicle steering control device comprising a failure determination means. The failure determination means is set to a value other than zero for a predetermined time or more after it is requested that the torque command value corresponding to the drive signal of the automatic steering control means be set to zero. 2. The vehicle steering control device according to claim 1, wherein the automatic steering control means is determined to have failed.

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