JP4119306B2 - Automatic vehicle steering system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle including an actuator that steers a wheel of a vehicle, a power source that supplies power to the actuator, and an actuator control unit that controls driving of the actuator based on a control target value that is stored or calculated in advance. The present invention relates to an automatic steering device.
[0002]
[Prior art]
Such an automatic steering device for a vehicle is known from the following patent document. In this automatic steering device, the relationship of the turning angle of the wheel with respect to the moving distance of the vehicle from the start position to the target position is stored in a table in advance, and the actuator moves the table from the start position to the target position. The wheel is automatically steered based on the above.
[0003]
[Patent Literature]
Japanese Patent Laid-Open No. 9-193691
[Problems to be solved by the invention]
By the way, when the relationship of the turning angle of the wheel with respect to the moving distance of the vehicle is stored in the table in advance, the turning of the wheel is delayed unless the driving speed of the actuator is increased in accordance with the increase in the vehicle speed. May not be correctly guided to the target position. In order to prevent this, the upper limit value of the vehicle speed may be regulated. However, in this case, there is a problem that it takes time to guide the vehicle to the target position. Even when the actuator is driven in a state where the vehicle is stopped, if the driving speed of the actuator is low, there is a problem that it takes a long time to steer and slows down the guidance of the vehicle to the target position.
[0005]
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to shorten the time for guiding the vehicle to the target position by increasing the wheel turning speed in the automatic steering device of the vehicle.
[0006]
[Means for Solving the Problems]
To achieve the above object, according to the first aspect of the present invention, an actuator that steers the wheels of a vehicle, a power source that supplies power to the actuator, and a control target value that is stored or calculated in advance is used. An automatic parking start switch for starting automatic parking by actuating the actuator, and an automatic parking start switch being turned on. automatic steering apparatus for vehicle is characterized in that a power supply voltage control means to increase the power supply voltage for supplying power to the actuator is proposed.
[0007]
According to the above configuration, when the automatic parking start switch is turned on to start the automatic parking by operating the actuator, the voltage of the power source that supplies electric power to the actuator is increased, so that the wheel turning speed can be increased. it can. As a result, when steering is performed while the vehicle is moving, the steering speed of the wheels is increased in accordance with the increase in the vehicle speed to increase the accuracy of the vehicle's movement trajectory and reduce the time for guiding the vehicle to the target position. In addition, when steering is performed while the vehicle is stopped, the time for guiding the vehicle to the target position by increasing the steering speed of the wheels can be shortened.
[0008]
According to the second aspect of the present invention, the actuator is steered based on an actuator that steers the wheels of the vehicle, a power source that supplies power to the actuator, and a control target value that is stored or calculated in advance. In the automatic vehicle steering apparatus including the actuator control means, the control target value is a first value that maintains a constant value even when the moving distance of the vehicle changes, and a first value that changes according to the moving distance of the vehicle. And a power supply voltage control means for increasing the voltage of a power supply that supplies power to the actuator when the control target value takes the second value. Is proposed.
[0009]
According to the above configuration, the control target value includes the first value that maintains a constant value even when the moving distance of the vehicle changes, and the second value that changes according to the moving distance of the vehicle. When the value takes the second value, the power supply voltage control means increases the voltage of the power supply that supplies power to the actuator, so the wheel turning speed can be increased. As a result, when steering is performed while the vehicle is moving, the steering speed of the wheels is increased in accordance with the increase in the vehicle speed to increase the accuracy of the vehicle's movement trajectory and reduce the time for guiding the vehicle to the target position. In addition, when steering is performed while the vehicle is stopped, the time for guiding the vehicle to the target position by increasing the steering speed of the wheels can be shortened. In addition, since the power supply voltage is increased only when the control target value changes, energy can be saved by minimizing the unnecessary increase in the power supply voltage.
[0010]
According to the invention described in claim 3 , in addition to the configuration of claim 1 or claim 2 , the power source is connected to a generator driven by a motor of a vehicle, and the power source voltage control means includes: An automatic steering apparatus for a vehicle is proposed in which the rotational speed of the prime mover is increased when the voltage of the power source is increased.
[0011]
According to the above arrangement, since the power supply is connected to a generator driven by the prime mover of the vehicle, it is possible to increase the voltage of the power supply by increasing the rotational speed of the prime mover.
[0012]
According to the fourth aspect of the present invention, the actuator is steered based on the actuator that steers the wheels of the vehicle, the power source that supplies power to the actuator, and the control target value that is stored or calculated in advance. In the vehicle automatic steering apparatus provided with the actuator control means, the power source includes a low voltage battery connected to the actuator, and a high voltage battery connected to a motor / generator as a driving source for traveling, and the actuator An automatic parking start switch for operating and starting automatic parking; and a power supply voltage control means for supplying power by connecting the high voltage battery to the actuator when the automatic parking start switch is turned on. An automatic vehicle steering device is proposed.
[0013]
According to the above configuration, the power source includes the low voltage battery connected to the actuator and the high voltage battery connected to the motor / generator as the driving source for traveling, and the automatic power for starting the automatic parking by operating the actuator. When the parking start switch is turned on, the power supply voltage control means connects the high voltage battery to the actuator to supply electric power, so that the wheel turning speed can be increased. As a result, when steering is performed while the vehicle is moving, the steering speed of the wheels is increased in accordance with the increase in the vehicle speed to increase the accuracy of the vehicle's movement trajectory and reduce the time for guiding the vehicle to the target position. In addition, when steering is performed while the vehicle is stopped, the time for guiding the vehicle to the target position by increasing the steering speed of the wheels can be shortened.
[0014]
The 12V battery 12 of the embodiment corresponds to the power source or low voltage battery of the present invention, the high voltage battery 17 of the embodiment corresponds to the power source or high voltage battery of the present invention, and the engine E of the embodiment corresponds to the prime mover of the present invention. The electronic control unit U of the embodiment corresponds to the actuator control means of the present invention, the front wheel Wf of the embodiment corresponds to the wheel of the present invention, and the reference turning angle θref of the embodiment corresponds to the control target value of the present invention. Correspond.
[0015]
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.
[0016]
1 to 5 show a first embodiment of the present invention. FIG. 1 is an overall configuration diagram of a vehicle equipped with an automatic steering device, FIG. 2 is an explanatory diagram of the operation of a back parking / left mode, and FIG. FIG. 4 is a diagram illustrating a selection switch and an automatic parking start switch, FIG. 4 is a diagram illustrating a power supply system to the actuator, and FIG. 5 is a diagram illustrating control of a power supply voltage of the actuator.
[0017]
As shown in FIG. 1, the vehicle V includes a pair of front wheels Wf, Wf and a pair of rear wheels Wr, Wr. The steering wheel 1 and the front wheels Wf and Wf, which are the steering wheels, rotate integrally with the steering wheel 1, the pinion 3 provided at the lower end of the steering shaft 2, the rack 4 that meshes with the pinion 3, and the 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. An 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 driver's operation of the steering handle 1 or to perform automatic steering for a garage to be described later.
[0018]
The steering control device 21 includes a control unit 22 and a storage unit 23. The control unit 22 includes a turning angle detection unit Sa that detects a turning angle θ that is a rotation angle of the steering handle 1, and a steering handle. Steering torque detection means Sb for detecting the steering torque T of one wheel, wheel rotation angle detection means Sc for detecting the rotation angle of the wheels Wf, Wf; Wr, Wr, and brake operation amount for detecting the operation amount of the brake pedal 9 Signals are input from the detection means Sd and the shift range detection means Se that detects the shift range (“D” range, “R” range, “N” range, “P” range, etc.) selected by the select lever 10. Is done.
[0019]
The control unit 22 is provided with power supply voltage control means 22a for controlling the voltage of the 12V battery 12 (see FIG. 4) that supplies power to the actuator 7.
[0020]
As is clear from FIG. 3, the mode selection switch Sf and the automatic parking start switch Sg operated by the driver are connected to the control unit 22. The mode selection switch Sf is operated when selecting one of four types of parking modes to be described later, that is, back parking / right mode, back parking / left mode, parallel parking / right mode, and parallel parking / left mode. With buttons. The automatic parking start switch Sg is operated when starting automatic parking in any mode selected by the mode selection switch Sf.
[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 wheels Wf, Wf; Wr, Wr by the rotation angle of the wheels Wf, Wf; Wr, Wr detected by the wheel rotation angle detection means Sc. It is done. For the calculation of the movement distance X, the high select value, low select value, or average value of the output of the wheel rotation angle detecting means Sc... Is used.
[0022]
Based on the signals from the detection means Sa to Se and the switches Sf and Sg and the parking mode data stored in the storage unit 23, the control unit 22 operates the actuator 7, a liquid crystal monitor, a speaker, The operation of the operation stage teaching device 11 including the lamp, chime, buzzer and the like and the voltage of the 12V battery 12 are controlled.
[0023]
As shown in FIG. 4, a generator 16 is connected to the engine E via a drive pulley 13, an endless belt 14, and a driven pulley 15, and the generator 16 supplies power to in-vehicle accessories and actuators 7. Connected to a 12V battery 12. The generator 16 that is driven by the engine E and generates a three-phase alternating current includes an AC-DC converter connected to the power supply voltage control means 22a, and has a low voltage (for example, 12V) direct current or a high voltage (for example, 16V) direct current. Is selectively output.
[0024]
Next, the operation of the embodiment of the present invention having the above-described configuration will be described.
[0025]
During normal times when automatic parking is not performed (when the mode selection switch Sf is not operated), the steering control device 21 functions as a general power steering control device. Specifically, when the driver operates the steering handle 1 to turn the vehicle V, the steering torque detecting means Sb detects the steering torque T input to the steering handle 1, and the control unit 22 is based on the steering torque T. The drive of the actuator 7 is controlled. As a result, the left and right front wheels Wf and Wf are steered by the driving force of the actuator 7, and the driver's steering operation is assisted.
[0026]
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.
[0027]
First, as shown in FIG. 2A, the vehicle V is moved to the vicinity of the garage to be parked by the driver's own steering operation, and the inside of the door is placed with the left side of the vehicle body as close as possible to the garage entrance line. The mark M (see FIG. 1) on the vehicle is stopped at the position where the mark M coincides with the center line of the garage (start position (1). Then, the mode selection switch Sf is operated to select the back parking / left mode. At the same time, when the automatic parking start switch Sg is turned on, automatic steering control is started.While automatic steering control is being performed, the operation stage teaching device 11 includes the current position of the vehicle, surrounding obstacles, the parking position, The target movement trajectory of the vehicle from the start position (1) to the target position (3), the return position (2) for switching from forward to reverse, etc. are displayed. Various instructions and alarms such as operation of the select lever 10 at the return position (2) are performed.
[0028]
A door mirror may be used instead of the mark M provided on the inside of the door, and the mark M and the door mirror may be aligned with the end of the garage instead of being aligned with the center line of the garage.
[0029]
With the automatic steering control, the driver releases the brake pedal 9 and creeps the vehicle V, and does not operate the steering handle 1, so that the front wheels are selected based on the back parking / left mode data selected by the mode selection switch Sf. Wf and Wf are automatically steered. That is, while the vehicle V moves forward from the start position (1) to the turn-back position (2), the front wheels Wf and Wf are automatically steered to the right, while the vehicle V moves backward from the turn-back position (2) to the target position (3). The front wheels Wf, Wf are automatically steered to the left.
[0030]
As apparent from FIG. 2B, during the automatic steering control, 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 Sa. The deviation E (= θref−θ) is calculated on the basis of the turning angle θ input from, and the operation of the 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.
[0031]
The automatic steering control is stopped when the driver turns off the mode selection switch Sf, but when the driver removes his foot from the brake pedal 9 or when the driver operates the steering handle 1, Return to normal power steering control.
[0032]
By the way, since the rotational speed of the actuator 7 made of an electric motor is determined by the power supply voltage, when the actuator 7 is driven by the 12V battery 12, it is necessary to suppress the vehicle speed during automatic steering to less than 5 km / h, for example. When the vehicle speed becomes 5 km / h or higher, there is a problem that the reference turning angle θref cannot follow the moving speed of the vehicle V and deviates from the target moving locus.
[0033]
Therefore, in the present embodiment, when the automatic parking start switch Sg is turned on and automatic parking is started, the engine E causes the command of the power supply voltage control means 22a of the electronic control unit U as shown in FIG. The voltage output from the driven generator 16 is increased from 12V in the normal state to 16V. As a result, the number of rotations of the actuator 7 is increased and the followability of the reference turning angle θref is increased, so that the vehicle V does not deviate from the target movement locus until the vehicle speed during automatic steering reaches, for example, 9 km / h. The vehicle speed during parking can be increased and parking can be completed in a short time.
[0034]
In FIG. 5 (A), when the reference turning angle θref is held at a constant value, that is, when the actuator 7 is not rotating, it is not necessary to increase the power supply voltage. In addition, the power supply voltage may be increased only when the actuator 7 is rotating, whereby the driving load of the generator 16 can be reduced and the fuel consumption of the engine E can be reduced. Instead of increasing the power supply voltage with the AC-DC converter provided in the generator 16, the power supply voltage may be increased by increasing the rotation speed of the engine E, that is, the rotation speed of the generator 16, when the actuator 7 is driven.
[0035]
When the power supply voltage is controlled as shown in FIG. 5C, the fact that the actuator 7 is rotating indicates that the time differential value of the steering angle θ of the steering handle 1 detected by the steering angle detection means Sa is It can be known from the fact that it is greater than or equal to a predetermined value, or that the position of the vehicle V is a position where the reference turning angle θref stored in the storage unit 23 changes.
[0036]
Next, a second embodiment of the present invention will be described with reference to FIG.
[0037]
The vehicle V of the first embodiment uses the engine E as a travel drive source, but the vehicle of the second embodiment is a hybrid vehicle or an electric vehicle provided with a motor / generator MG as a travel drive source.
[0038]
This vehicle includes, for example, a 144 V high voltage battery 17, and a power control unit 18 is provided between the motor / generator MG and the high voltage battery 17. Therefore, when the motor / generator MG functions as a motor, the DC of 144V of the high-voltage battery 17 is converted into a three-phase AC by the power control unit 18 and supplied to the motor / generator MG, and reversely transmitted from the drive wheels during regenerative braking. When the motor / generator MG is caused to function as a generator with the generated driving force, the three-phase alternating current generated by the motor / generator MG is converted into direct current by the power control unit 18 to charge the high voltage battery 17.
[0039]
A DC-DC converter 19 controlled by the power supply voltage control means 22a of the electronic control unit U is arranged between the high voltage battery 17 and the 12V battery 12, and the voltage of 144V of the high voltage battery 17 is DC− The DC converter 19 steps down the voltage to 12V to charge the 12V battery 12, and at the time of automatic steering, the voltage of 144V of the high voltage battery 17 is lowered to 16V by the DC-DC converter 19 to drive the actuator 7 at high speed.
[0040]
Thus, the second embodiment can achieve the same effects as those of the first embodiment.
[0041]
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.
[0042]
For example, in the embodiment, the movement locus of the vehicle V up to the target position (3) is stored in the storage unit 23 in advance. However, the movement locus can be calculated from the current position of the vehicle V and the target position (3). It is.
[0043]
In the embodiment, the reference turning angle θref is set as a value that changes in accordance with the moving distance of the vehicle V from the start position (1) to the target position (3), but the reference turning angle θref is constant. You may set to the value which can guide the vehicle V to a target position by turning angle (theta). That is, the steering angle θ may be fixed and the vehicle V may be moved along the arcuate movement locus to be guided to the target position (3). In this way, the setting of the reference turning angle θref and the control of the actuator 7 can be simplified. In this case, the steering is performed by driving the actuator 7 while the vehicle V is stopped. By increasing the power supply voltage, the steering speed of the front wheels Wf and Wf is increased to bring the vehicle V to the target position (3). The time taken to lead to can be shortened.
[0044]
In the embodiment, the power supply voltage is uniformly boosted from 12 V to 16 V when the actuator 7 is driven. However, if the power supply voltage is boosted according to the actual driving speed of the actuator 7 or the target driving speed of the actuator 7. The reference turning angle θref can be accurately reproduced while minimizing the energy for boosting the power supply voltage. At this time, the actual drive speed of the actuator 7 can be calculated from the time differential value of the turning angle θ of the steering handle 1 detected by the turning angle detection means Sa, and the target driving speed of the actuator 7 is stored in the storage unit. It can be calculated by applying the vehicle speed to the data of the reference turning angle θref stored in 23.
[0045]
【The invention's effect】
According to the invention described in claim 1 as described above, when the automatic parking start switch in order to start the automatic parking by operating the actuator is turned ON, since increasing the power supply voltage for supplying power to the actuator , Can increase the wheel steering speed. As a result, when steering is performed while the vehicle is moving, the steering speed of the wheels is increased in accordance with the increase in the vehicle speed to increase the accuracy of the vehicle's movement trajectory and reduce the time for guiding the vehicle to the target position. In addition, when steering is performed while the vehicle is stopped, the time for guiding the vehicle to the target position by increasing the steering speed of the wheels can be shortened.
[0046]
According to the second aspect of the present invention, the control target value is a first value that maintains a constant value even if the moving distance of the vehicle changes, and a second value that changes according to the moving distance of the vehicle. Since the power supply voltage control means increases the voltage of the power supply that supplies power to the actuator when the control target value takes the second value, the wheel turning speed can be increased. As a result, when steering is performed while the vehicle is moving, the steering speed of the wheels is increased in accordance with the increase in the vehicle speed to increase the accuracy of the vehicle's movement trajectory and reduce the time for guiding the vehicle to the target position. In addition, when steering is performed while the vehicle is stopped, the time for guiding the vehicle to the target position by increasing the steering speed of the wheels can be shortened. In addition, since the power supply voltage is increased only when the control target value changes, energy can be saved by minimizing the unnecessary increase in the power supply voltage.
[0047]
According to the invention described in claim 3, since the power supply is connected to a generator driven by the prime mover of the vehicle, it is possible to increase the voltage of the power supply by increasing the rotational speed of the prime mover.
[0048]
According to the invention described in claim 4 , the power source includes a low voltage battery connected to the actuator and a high voltage battery connected to a motor / generator as a driving source for traveling, and automatically operates by operating the actuator. When the automatic parking start switch for starting parking is turned on, the power supply voltage control means connects the high voltage battery to the actuator to supply electric power, so that the wheel turning speed can be increased. As a result, when steering is performed while the vehicle is moving, the steering speed of the wheels is increased in accordance with the increase in the vehicle speed to increase the accuracy of the vehicle's movement trajectory and reduce the time for guiding the vehicle to the target position. In addition, when steering is performed while the vehicle is stopped, the time for guiding the vehicle to the target position by increasing the steering speed of the wheels can be shortened.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a vehicle equipped with an automatic steering device. FIG. 2 is an explanatory diagram of the operation of a back parking / left mode. FIG. 3 is a diagram showing a mode selection switch and an automatic parking start switch. FIG. 5 is a diagram showing the control of the power supply voltage of the actuator. FIG. 6 is a diagram showing the power supply system to the actuator according to the second embodiment of the present invention.
7 Actuator 12 12V battery (Power supply , Low voltage battery )
16 Generator
17 High voltage battery (power supply)
22a Power supply voltage control means E Engine (motor)
MG Motor Generator
Sg automatic parking start switch U Electronic control unit (actuator control means)
V Vehicle Wf Front wheel (wheel)
θre Standard turning angle (control target value)

Claims (4)

An actuator (7) that steers the wheel (Wf) of the vehicle (V), a power source (12) that supplies power to the actuator (7), and an actuator based on a control target value (θre) that is stored or calculated in advance In an automatic steering device for a vehicle, comprising an actuator control means (U) for controlling the drive of (7),
An automatic parking start switch (Sg) for starting the automatic parking by operating the actuator (7), and a power supply for supplying electric power to the actuator (7) when the automatic parking start switch (Sg) is turned on ( automatic steering apparatus for a vehicle, characterized in that a supply voltage control means (22a) to increase the voltage of the 12). An actuator (7) that steers the wheel (Wf) of the vehicle (V), a power source (12) that supplies power to the actuator (7), and an actuator based on a control target value (θref) that is stored or calculated in advance In an automatic steering device for a vehicle, comprising an actuator control means (U) for controlling the drive of (7),
The control target value (θref) includes a first value that maintains a constant value even when the moving distance of the vehicle (V) changes, and a second value that changes according to the moving distance of the vehicle (V). Including
Power supply voltage control means (22a) for increasing the voltage of the power supply (12) that supplies power to the actuator (7) when the control target value (θref) takes the second value is provided. Automatic steering device for vehicles. The power source (12) is connected to a generator (16) driven by a prime mover (E) of a vehicle (V), and the power source voltage control means (22a) increases the voltage of the power source (12). The automatic steering device for a vehicle according to claim 1 or 2 , wherein the rotational speed of the prime mover (E) is increased. Based on the actuator (7) for turning the wheel (Wf) of the vehicle (V), the power sources (12 , 17 ) for supplying electric power to the actuator (7), and the control target value (θref) stored or calculated in advance. An automatic steering apparatus for a vehicle comprising actuator control means (U) for controlling the drive of the actuator (7),
The power source includes a low voltage battery (12) connected to the actuator (7), and a high voltage battery (17) connected to a motor generator (MG) as a driving source for traveling,
An automatic parking start switch (Sg) for operating the actuator (7) to start automatic parking, and when the automatic parking start switch (Sg) is turned on, the high voltage battery (17) is connected to the actuator (7). And a power supply voltage control means (22a) for supplying power by connecting to the vehicle.

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