JP4129100B2 - Automatic vehicle steering system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic vehicle steering apparatus for automatically parking a vehicle without depending on a steering operation of a driver.
[0002]
[Prior art]
Such automatic steering devices for vehicles are already known from Japanese Patent Application Laid-Open Nos. 4-55168 and 11-78936. These automatic vehicle steering devices use a steering actuator of a conventionally known electric power steering device, and control the steering actuator based on the relationship between the vehicle movement distance and the turning angle stored in advance. Parking and parallel parking are performed automatically.
[0003]
[Problems to be solved by the invention]
By the way, in the above-mentioned conventional one, the steering actuator is controlled based on the relationship between the movement distance of the vehicle and the turning angle stored in advance, so that the wheel may be locked or idle during the automatic steering control. If the moving distance of the vehicle cannot be detected correctly, the steering actuator is controlled based on the erroneously detected moving distance of the vehicle, and there is a problem that the vehicle cannot be moved along the correct moving path. Even if the movement locus is not set based on the movement distance of the vehicle, there is a problem that when the wheel is locked or idling, the vehicle turns or moves laterally and deviates from the correct movement locus.
[0004]
The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent a vehicle from deviating from a correct movement locus when a rotational state of a wheel becomes abnormal during automatic steering control.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a movement trajectory setting means for storing or calculating a movement trajectory of a vehicle up to a target position, a steering actuator for turning wheels, Detecting a rotation angle or a rotation speed of a wheel in an automatic vehicle steering apparatus having actuator control means for controlling driving of a steering actuator based on a movement locus set by a movement locus setting means while moving to a target position The actuator control means determines whether the wheel rotation state is normal or abnormal based on the detection result of the detection means, and controls the steering actuator when the determination result is abnormal. autopilot suggestions vehicle, characterized in that by stop to prevent deviation from the movement locus of the vehicle It is.
[0006]
According to the above configuration, the driving of the steering actuator is controlled based on whether the rotation state of the wheel detected by the detection means is normal or abnormal, and if it is determined that the rotation state of the wheel is abnormal, the steering actuator by the actuator control means Therefore, it is possible to prevent the vehicle from deviating from the correct movement locus due to automatic steering during abnormal rotation of the wheels.
[0007]
According to the invention described in claim 2, in addition to the configuration of claim 1, the actuator control means is configured so that the rotation change rate of any wheel suddenly increases or decreases, or the rotation change rate of all wheels. If the deviation between the rotational speed of one of the wheels and the rotational speed of the other wheel exceeds a predetermined threshold even if is normal, it is determined to be abnormal and the control of the steering actuator is stopped. An automatic steering device for a vehicle is proposed.
[0009]
According to a third aspect of the present invention, in addition to the configuration of the first aspect, the rotation state of the wheel determined by the actuator control means is an idling state or a locked state of the wheel. An automatic steering device is proposed.
[0010]
According to the above configuration, since the actuator control means detects the idling state or the locked state of the wheel, it is possible to prevent the vehicle from idling or locking and deviating from the correct movement trajectory.
[0011]
According to a fourth aspect of the present invention, in addition to any one of the first to third aspects, when the wheel rotation state determined by the actuator control means is abnormal, the abnormal state is taught to the driver. There is proposed an automatic steering apparatus for a vehicle characterized by comprising teaching means for performing the above-described teaching.
[0012]
According to the above configuration, when it is determined that the rotational state of the wheel is abnormal, the teaching means teaches the driver the abnormal state, so that the driver performs spontaneous steering so that the vehicle does not deviate from the correct movement locus. Can do.
[0013]
According to the invention described in claim 5, in addition to any of the configurations of claims 1 to 4, wherein the actuator control means, when it is determined that the abnormality, the abnormality of the state continues for a predetermined time In this case, an automatic vehicle steering apparatus is proposed in which the control of the steering actuator is stopped.
[0015]
The control unit 22 of the embodiment corresponds to the actuator control means of the present invention, the storage unit 23 of the embodiment corresponds to the movement trajectory setting means of the present invention, and the front wheel Wf and the rear wheel Wr of the embodiment correspond to those of the present invention. Corresponding to the wheel, the front wheel rotation angle detection means Sf ₃ and the rear wheel rotation angle detection means Sr ₃ of the embodiment correspond to the detection means of the present invention.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings.
[0017]
1 to 4 show an embodiment of the present invention. FIG. 1 is an overall configuration diagram of a vehicle equipped with a steering control device, FIG. 2 is an explanatory diagram of the operation of a back parking / left mode, and FIG. 3 is a mode selection. The figure which shows a switch and an automatic parking start switch, FIG. 4 is a flowchart explaining an effect | action.
[0018]
As shown in FIG. 1, the vehicle V includes a pair of front wheels Wf, Wf and a pair of rear wheels Wr, Wr. Steering wheel 1 and front wheels Wf, Wf as steering wheels rotate integrally with steering wheel 1, steering shaft 2, pinion 3 provided at the lower end of steering shaft 2, rack 4 meshing with pinion 3, and rack 4 Are connected by left and right tie rods 5, 5 provided at both ends, and left and right knuckles 6, 6 connected to tie rods 5, 5. A steering actuator 7 made of an electric motor is connected to the steering shaft 2 via a worm gear mechanism 8 in order to assist the operation of the steering wheel 1 by the driver or to perform automatic steering for a garage to be described later.
[0019]
The steering control unit 21 is composed of a control unit 22 storage unit 23, the control unit 22, and the steering angle detecting means S ₁ for detecting the turning angle θ is the rotation angle of the steering wheel 1, steering a steering torque detecting means S ₂ for detecting a steering torque T of the wheel 1, the left and right front wheels Wf, a front wheel rotational angle detecting means Sf _3, Sf ₃ for detecting the rotation angle of Wf, left and right rear wheels Wr, Wr rotation Rear wheel rotation angle detection means Sr ₃ , Sr ₃ for detecting the angle, brake operation amount detection means S ₄ for detecting the operation amount of the brake pedal 9, and the shift range (“D” range, "R" range, "N" range, the signal from the shift range detecting means S ₅ Metropolitan to detect "P" range, etc.) is input.
[0020]
As is clear from FIG. 3, the mode selection switch S ₆ and the automatic parking start switch S ₇ operated by the driver are connected to the control unit 22. Mode selecting switch S ₆ is operated to select later-described four types of parking mode, i.e. reverse parking / right mode, reverse parking / left mode, one of the parallel parking / right mode and parallel parking / left mode 4 buttons are provided. Automatic parking start switch S ₇ is operated to start automatic parking according to any of the mode selected by the mode selection switch S _6.
[0021]
In the storage unit 23, the data of the four types of parking modes, that is, the relationship of the reference turning angle θref with respect to the movement distance X of the vehicle V is stored in advance as a table. The moving distance X of the vehicle V is obtained by multiplying the known circumference of the front wheel Wf by the rotation angle of the front wheel Wf detected by the front wheel rotation angle detection means Sf ₃ and Sf ₃ . For calculating the movement distance X, the high select value, the low select value, or the average value of the outputs of the pair of left and right front wheel rotation angle detecting means Sf ₃ and Sf ₃ is used.
[0022]
Based on the signals from the detection means S _{1 to} S ₅ and the switches S ₆ and S ₇ and the parking mode data stored in the storage unit 23, the control unit 22 operates the steering actuator 7; It controls the operation of the operation stage teaching device 11 including a liquid crystal monitor, a speaker, a lamp, a chime, a buzzer, and the like.
[0023]
Next, the operation of the embodiment of the present invention having the above-described configuration will be described.
[0024]
The normal time when not used to automatically parking (when the mode selecting switch S ₆ is not operated), the steering control apparatus 21 functions as a general power steering control unit. Specifically, when the driver operates the steering wheel 1 to turn the vehicle V, the steering torque detection means S ₂ detects the steering torque T input to the steering wheel 1, and the control unit 22 determines the steering torque T. Based on this, the driving of the steering actuator 7 is controlled. As a result, the left and right front wheels Wf and Wf are steered by the driving force of the steering actuator 7, and the driver's steering operation is assisted.
[0025]
Next, the content of the automatic steering control will be described by taking the back parking / left mode (a mode in which the vehicle is parked while backing to the parking position on the left side of the vehicle V) as an example.
[0026]
First, as shown in FIG. 2 (A), the vehicle V is moved to the vicinity of the garage to be parked by the driver's own steering operation, and is determined in advance with the left side of the vehicle body as close as possible to the garage entrance line. The vehicle V is stopped at a position (start position {circle around (1)}) where the reference (for example, a mark or side mirror provided inside the door) coincides with the center line of the garage. Then, ON the automatic parking start switch S ₇ with to select the back parking / left mode by operating the mode selection switch S ₆ Then, the automatic steering control is started. While the automatic steering control is being performed, the operation stage teaching device 11 switches the current position of the own vehicle, surrounding obstacles, the parking position, the predicted movement trajectory of the own vehicle from the start position to the target position, and switching from forward to reverse. The turn-back position and the like are displayed, and various instructions and warnings such as operation of the select lever 10 at the turn-back position are given to the driver by sound from the speaker.
[0027]
The automatic steering control, the driver based on data alone without operating the steering wheel 1, reverse parking / left mode selected by the mode selection switch S ₆ is creeping vehicle V loosen the brake pedal 9 The front wheels Wf, Wf are automatically steered. That is, while the vehicle V moves forward from the start position {circle over (1)} to the turning position {circle around (2)}, the front wheels Wf and Wf are automatically steered to the right, while the vehicle V moves backward from the turning position {circle around (2)} to the target position {circle around (3)}. The front wheels Wf, Wf are automatically steered to the left.
[0028]
As apparent from FIG. 2 (B), during automatic steering, the control unit 22 reads the back parking / left mode reference turning angle θref read from the storage unit 23 and the turning angle detection means S _1. The deviation E (= θref−θ) is calculated on the basis of the turning angle θ input from, and the operation of the steering actuator 7 is controlled so that the deviation E becomes zero. At this time, since the data of the reference turning angle θref is set corresponding to the moving distance X of the vehicle V, the vehicle V always moves on the moving locus even if there is a slight fluctuation in the vehicle speed of the creep travel. It will be.
[0029]
Since the automatic steering control is performed while the driver steps on the brake pedal 9 and the vehicle creeps, the vehicle V can be stopped by quickly depressing the brake pedal 9 when the driver finds an obstacle. .
[0030]
The above-described automatic steering control is stopped when the driver turns off the mode selection switch S ₆ , but in addition, when the driver releases his foot from the brake pedal 9 or when the driver operates the steering wheel 1. Canceled and returns to normal power steering control.
[0031]
By the way, since the front wheels Wf and Wf of the vehicle V of the present embodiment are drive wheels, if the road surface friction coefficient is small, there is a possibility of not only locking during automatic steering control but also idling. If the front wheels Wf and Wf are locked during the automatic steering control, the front wheel rotational speed detection means Sf ₃ and Sf ₃ do not detect the rotation of the front wheels Wf and Wf even though the vehicle V is actually moving. The moving distance X of the vehicle V to be detected is not detected. Conversely, if the front wheels Wf and Wf idle during automatic steering control, the front wheel speed detection means Sf ₃ and Sf ₃ detect the rotation of the front wheels Wf and Wf even though the vehicle V is not actually moving. The moving distance X of the vehicle V that should not be detected is detected. When the movement distance X of the vehicle V is erroneously detected in this way, the data of the reference turning angle θref is set corresponding to the movement distance X of the vehicle V, and thus a deviation occurs in the movement locus of the vehicle V. Resulting in. Therefore, in this embodiment, the shift of the movement locus of the vehicle V is prevented as follows.
[0032]
Figure flowchart of step S1 of 4, S2 wheel rotation angle detecting means Sf ₃ in, Sf left and right front wheels Wf by _3, detects the rotation angle of Wf, steps S3, S4 at the rear wheel rotation angle detecting means Sr _3, Sr ₃ Thus, the rotation angles of the left and right rear wheels Wr, Wr are detected. If the rotational change rate of any of the wheels is abnormal in steps S5 to S8, that is, if the rotational speed is suddenly reduced by locking or if the rotational speed is suddenly increased by idling, the process proceeds to step S9 and the operation stage teaching device. 11 informs the driver that the wheel is locked or idle. If the abnormal state of the rotational speed of the wheel is severe in step S10, the automatic steering control is stopped in step S11. If the abnormal state is mild, the automatic steering control is continued in step S14.
[0033]
On the other hand, if the rotation change rates of the four wheels are normal in steps S5 to S8, the rotation states of the four wheels are compared in step S12. As a result, if the rotational state of any of the wheels is abnormal in step S13, that is, if the deviation between the rotational speed of any of the wheels and the rotational speed of the other wheels exceeds a predetermined threshold value, step S9 is performed. If the abnormal state of the rotational speed of any one of the wheels is severe in step S10, the automatic steering control is stopped in step S11, and if the abnormal state is mild, the process proceeds to step S14. Continue automatic steering control. If the rotation state of all the wheels is normal in step S13, automatic steering control is continued in step S14.
[0034]
The determination of whether the abnormal state is severe or light in step S10 is made based on, for example, the time during which locking or idling continues. Assuming that the allowable displacement of the target position (3) (the displacement of the garage in the depth direction) is 40 cm, the automatic steering control is normally performed at a vehicle speed of 5 km / h or less, so the vehicle V advances by 40 cm at a vehicle speed of 5 km / h. It is possible to determine whether the abnormal state is severe or mild based on the time of 0.3 seconds. In this case, if the duration of lock or idling is 0.3 seconds or more, it is determined that the abnormal state is severe, and if it is less than 0.3 seconds, the abnormal state is determined to be mild. Of course, this criterion can be changed as appropriate.
[0035]
As described above, if the wheel is locked or idling during the automatic steering control of the vehicle V, this is notified to the driver, and further, the automatic steering control is stopped. Can be prevented. Accordingly, the driver may execute the automatic steering control again while taking care that the wheels do not lock or idle, or enter the garage by spontaneous steering without performing the automatic steering control.
[0036]
In this embodiment, the movement locus of the vehicle V is set as a function of the movement distance X. Therefore, when the front wheels Wf and Wf which are detection wheels of the movement distance X are locked or idle, the movement distance X is not accurately detected. This has a particularly large effect on the deviation of the movement trajectory. The wheel lock may occur on either the driving wheel or the driven wheel, but the idling of the wheel occurs only on the driving wheel. Therefore, if the driven wheel is used as the detection wheel of the movement distance X, the wheel idling occurs. The detection error of the movement distance X can be avoided.
[0037]
Although the embodiments of the present invention have been described above, various design changes can be made without departing from the scope of the present invention.
[0038]
For example, in the embodiment, the movement locus of the vehicle V to the target position is stored in the storage unit 23 in advance, but the movement locus can be calculated from the current position and the target position of the vehicle V.
[0039]
In the embodiment, the reference turning angle θref is set as a function of the movement distance X, but it can also be set as a function other than the movement distance X (for example, a function of time).
[0040]
In the embodiment, the front wheels Wf and Wf are used as detection wheels for the movement distance X, but the rear wheels Wr and Wr may be used as detection wheels for the movement distance X.
[0041]
Further, the front wheel rotation angle detection means Sf ₃ and Sf ₃ and the rear wheel rotation angle detection means Sr ₃ and Sr ₃ may be those provided in advance for the antilock brake system or for traction control.
[0042]
Further, the rotation state of the wheel detected by the detection means is not limited to the rotation angle, and may be a rotation speed.
[0043]
【The invention's effect】
As described above, according to the first aspect of the present invention, the driving of the steering actuator is controlled based on whether the rotation state of the wheel detected by the detection means is normal or abnormal , and the rotation state of the wheel is abnormal. If the determination is made, the control of the steering actuator by the actuator control means is stopped, so that it is possible to prevent the vehicle from deviating from the correct movement locus by performing automatic steering during abnormal rotation of the wheels.
[0044]
Further, according to the invention described in claim 2, the actuator control means can detect any of the cases where the rotational change rate of any wheel suddenly increases or decreases, or even if the rotational change rate of all the wheels is normal. When the deviation between the rotational speed of the wheel and the rotational speed of the other wheel exceeds a predetermined threshold value, it is determined that there is an abnormality and the control of the steering actuator is stopped .
[0045]
According to the invention described in claim 3, since the actuator control means detects the idling state or the locking state of the wheel, it is possible to prevent the wheel from idling or locking and deviating from the correct movement locus of the vehicle. .
[0046]
According to the invention described in claim 4, when it is determined that the rotational state of the wheels is abnormal, the teaching means teaches the driver the abnormal state, so that the driver does not deviate from the correct movement locus. Spontaneous steering can be performed.
[0047]
According to a fifth aspect of the present invention, when it is determined that there is an abnormality , the actuator control means stops the control of the steering actuator only when the abnormality state continues for a predetermined time .
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a vehicle equipped with a steering control device. FIG. 2 is a diagram illustrating the operation of a back parking / left mode. FIG. 3 is a diagram illustrating a mode selection switch and an automatic parking start switch. Flowchart [Explanation of symbols]
7 Steering actuator 11 Operation stage teaching device (teaching means)
22 Control unit (actuator control means)
23 storage unit (movement trajectory setting means)
V Vehicle Wf Front wheel (wheel)
Wr Rear wheel (wheel)
Sf ₃ front wheel rotation angle detection means (detection means)
Sr ₃ rear wheel rotation angle detection means (detection means)

Claims (5)

A movement locus setting means (23) for storing or calculating a movement locus of the vehicle (V) to the target position;
A steering actuator (7) for steering the wheel (Wf);
Actuator control means (22) for controlling the driving of the steering actuator (7) based on the movement locus set by the movement locus setting means (23) while the vehicle (V) moves to the target position;
In an automatic steering device for a vehicle equipped with
Detection means (Sf ₃ , Sr ₃ ) for detecting the rotation angle or rotation speed of the wheels (Wf, Wr) is provided, and the actuator control means (22) detects the detection means (Sf ₃ , Sr ₃ ). Based on the result, it is determined whether the rotational state of the wheels (Wf, Wr) is normal or abnormal. When the determination result is abnormal, the control of the steering actuator (7) is stopped and the movement locus of the vehicle (V) is determined. An automatic steering device for a vehicle, which prevents deviation from the vehicle. The actuator control means (22) is either in the case where the rotational change rate of any wheel (Wf, Wr) suddenly increases or decreases, or even if the rotational change rate of all wheels (Wf, Wr) is normal. If the deviation between the rotational speed of the other wheel (Wf, Wr) and the rotational speed of the other wheel (Wf, Wr) exceeds a predetermined threshold value, it is determined that there is an abnormality and the steering actuator (7) The automatic steering apparatus for a vehicle according to claim 1, wherein control of the vehicle is stopped . The vehicle automatic according to claim 1, wherein the rotation state of the wheel (Wf, Wr) determined by the actuator control means (22) is an idling state or a locked state of the wheel (Wf, Wr). Steering device.   The teaching means (11) for teaching the driver of the abnormal state when the rotation state of the wheels (Wf, Wr) determined by the actuator control means (22) is abnormal is provided. 4. The automatic steering device for a vehicle according to any one of 3 above. The said actuator control means (22) stops control of the said steering actuator (7), only when this abnormality state continues for the predetermined time, when it determines with the said abnormality, The said actuator control means (22) is characterized by the above-mentioned . 4. The automatic steering device for a vehicle according to any one of 4 above.

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