JPH0675629A - Garage guidance device for vehicle - Google Patents

Abstract

PURPOSE:To provide the vehicle garage guidance device which guides the vehicle into a garage by continuous steering wheel operation and gives a smooth driving feeling. CONSTITUTION:A laser scanner 15 set on the vehicle 12 measures the coordinates and attitude angle of the vehicle to the garage and calculates a guidance line. The steering wheel 17 is driven toward the guidance line under the command of an ECU 16 and the vehicle coordinates are calculated from the steering wheel angle and movement distance data. In this state, the coordinates and attitude angle when the steering wheel is fully turned are estimated and the radius of such a turn that the vehicle moves onto the center axis in the garage is found from the estimated values; while the radius of the turn becomes the minimum radius of a turn of the vehicle, the steering wheel 17 is driven at an equal speed in the largest reverse direction to make a circular turn. During this circular turn, the attitude angle when the steering wheel is rotated to the center is estimated from the calculated vehicle coordinates and when the garage center axis matches the attitude angle, the steering wheel is turned to the center at an equal speed and the vehicle travels straight inwardly in the garage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention does not require stationary steering for driving the steering while the vehicle is stopped,
The present invention relates to a garage guidance device for a vehicle that continuously steers steering and automatically guides the vehicle into the garage.

[0002]

2. Description of the Related Art In an automatic vehicle driving system, there is a demand for a garage guidance device which guides the vehicle back into the garage by driving the vehicle backward. In such a garage guidance device, a guidance route to the garage entrance is obtained based on the current position coordinates and posture angle of the vehicle, and the vehicle is automatically driven in accordance with the guidance route. 12
A guidance device as disclosed in Japanese Patent No. 8416 has been considered.

The guide line of a vehicle along such a guide system is basically constituted by a combination of two circular turns and a straight line. For example, as shown in FIG.
If the coordinates Qx and the attitude angle ξ of the vehicle 12 with respect to the central axis of the vehicle are obtained, the first turning circle of radius R1 centered on O1 for placing the vehicle 12 on the central axis of the garage, and O2 as the center. The guide route is set by combining the second turning radius of the radius R2 and the straight line.

In such a guide route, the first turning radius R1 and the first turning angle θ1 can be set arbitrarily, but the second turning radius R2 and the second turning angle θ2 are
If the relationship shown by the following equation is satisfied, the vehicle 12 can be placed on the central axis of the garage 11.

[0005]

[Equation 1] However, Qx: initial X coordinate of the vehicle ξ: initial posture angle of the vehicle Here, the relationship between the steering angle and the turning radius has a characteristic peculiar to the vehicle and can be appropriately expressed by a map. Therefore, if the steering sensor for detecting the steering angle is provided in the steering of the vehicle 12 and the steering actuator is driven corresponding to the detected steering angle, the turning radii R1 and R2 can be realized in the actual vehicle as a function of the steering angle.

Although the turning angles θ1 and θ2 cannot be directly measured in the vehicle 12, the vehicle travel distance on an arc,
Specifically, the distance sensor can measure (R1 .theta.1) in the first turn and (R2 .theta.2) in the second turn. Therefore, these two circular turns can be realized in an actual vehicle, and these circular turns are a-b in FIG.
bc movement.

After the vehicle 12 is moved to the point c, this c
Although it is guided from the point to the back of the garage 11, its travel distance (straight line distance between cd) can easily geometrically calculate the travel distance on the garage center axis. If you move the distance along the garage center axis,
The garage guidance is completed.

In the case of such guidance control, in the first stage,
The vehicle 12 is temporarily stopped when the vehicle 12 reaches the point b, that is, when the vehicle makes the first turn, that is, when the vehicle 12 reaches the point b. Then, after that, the second turn to the point c is guided, the vehicle 12 is stopped at the point c, and then the final guidance to the back of the garage 12 is performed.

Therefore, in such garage guidance control, the vehicle 12 is always stopped once at the end of one guidance operation, and the steering operation is executed at this stop position. For this reason, the operation of the vehicle 12 is not smoothly performed, and a jerky driving impression is given. Further, due to the repetition of the operations of stopping and stationary, extra time (about 10 seconds) is required for guidance.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and continuously without stopping and stationary operation which requires a considerably long time loss when guiding the garage. An object of the present invention is to provide a garage guidance device for a vehicle that can perform steering by steering and eliminate time loss due to a vehicle stop.

[0011]

A vehicle guidance system according to the present invention includes a steering steering means for automatically steering the steering of the vehicle, and a steering angle detection means for detecting the steering angle of the steering wheel. A coordinate measuring means for measuring the coordinates and the attitude angle of the vehicle is provided, and the guide route to be placed on the central axis of the garage is obtained based on the coordinates and the attitude angle of the vehicle. Then, the first steering control means steers the steering at a constant speed toward the first turn of the guide route, and based on the continuously changing steering angle and vehicle travel distance by the first current coordinate calculation means. The current coordinate and posture angle of the vehicle are obtained, and the estimated coordinate and the posture angle when the steering is steered in the reverse direction to the maximum are obtained based on the current coordinate and the posture angle calculated by the first coordinate estimating means. Ask. Further, based on the coordinates and attitude angle estimated by the final turning radius calculation means, the turning radius for the vehicle to ride on the central axis of the garage is obtained, and the final turning radius and the minimum turning radius of the vehicle are compared, In a state where the final turning radius is larger than the minimum turning radius, the first steering control means causes the vehicle to perform the first turning travel at an extremely low speed. Further, in a state where it is determined that the final turning radius is equal to or smaller than the minimum turning radius, the second steering control for steering the steering toward the maximum in the opposite direction at a constant speed is performed. This second
The current attitude angle of the vehicle is obtained by the second current coordinate calculating means based on the steering angle and the vehicle moving distance that continuously change in the state of the steering control, and the current calculated by the second coordinate calculating means is calculated. Based on the attitude angle, the second coordinate estimating means obtains an estimated attitude angle when the steering wheel is returned to the center, and the estimated attitude angle obtained by the second coordinate estimating means is the vehicle in the garage. The second turning traveling is performed at an extremely low speed until the vehicle reaches the central axis line, and the estimated posture angle obtained by the second coordinate estimating means by the third steering control means is such that the vehicle is at the garage center. With the axis on,
The steering is performed with the steering being centered.

[0012]

According to the garage guidance device for a vehicle configured as described above, the guidance route to the garage is obtained based on the position coordinates and the attitude angle of the vehicle with respect to the measured position of the garage. A first turn is performed in which the vehicle travels at an extremely low speed while moving the steering wheel at a constant speed. In this first turning state, the estimated coordinates and the estimated attitude angle when the steering is turned to the maximum in the direction opposite to the operation direction are obtained, and the turning radius for getting on the vehicle center axis at this estimated coordinate position is determined. It is calculated. Then, the turning radius is compared with the minimum turning radius of the vehicle, and the steering is operated in the opposite direction at a constant speed and the vehicle is driven at an extremely low speed in a state where the turning radius for riding on the garage axis is the minimum turning radius. The vehicle is guided by the second turn such that the vehicle rides on the central axis of the garage.
That is, the steering is continuously steered from the first turn to the second turn without stopping the vehicle, and smooth and continuous guidance to the garage entrance is performed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a guided vehicle 12, and a laser scanning device 15 is provided at the rear portion of the vehicle 12. The laser scanning device 15 scans the laser light toward the rear of the vehicle 12 in a horizontal plane, detects reflected laser light from a reference position setting means such as a reflector set at the entrance of the garage, and the vehicle 12 The distance and azimuth from the to the reference position can be measured.

As shown in FIG. 2, the laser scanning device 15 is an electronic control unit (EC) mounted on the vehicle 12.
U) The operation is controlled by a command from 16, and a steering steering angle (rotation angle) signal from a steering sensor 18, which is mounted on the steering 17 and detects the rotation angle of the steering 17, is input to the ECU 16. In addition, a distance sensor 19 that generates pulse signals in response to wheel rotation
The vehicle speed pulse from is input. The travel distance of the vehicle 12 is measured by counting the vehicle speed pulses in the ECU 16.

Then, the ECU 16 obtains the coordinate position of the vehicle 12 with respect to the garage entrance, the attitude angle with respect to the garage center axis, and the like, and the CRT 21 via the CRT controller 20.
To be displayed on.

Further, a command is given to the steering driver 22 to drive a steering actuator 23 constituted by a motor for directly rotating the steering 17, so that the steering 17 is steered by a command from the ECU 16. Further brake actuator
A command is given to 24 so that the vehicle 12 is stopped. Reference numeral 26 is a switch for instructing the start or stop of such guidance control.

When the ECU 17 wants to automatically steer the steering wheel 17, the ECU gives commands to the steering driver 22, such as steering speed, direction and angle.
The steering driver 22 outputs a control signal that realizes this instruction to the steering actuator 23. The steering 17 is rotated at the rotation speed as instructed by the ECU 16 in the direction indicated by the angle and then stopped and fixed. It

Here, the rotation angle of the steering wheel 17 is set by the steering driver 22 detecting and controlling the sensor output by, for example, a hall element incorporated in the steering actuator 23. The steering sensor 18 is used by the ECU 16 for recognizing a rotation angle signal corresponding to the current position of the steering wheel 17 and utilizing it in the guidance logic. The position control of the motor of the steering actuator 23 is a sensor built in the steering actuator 23. Done by

The brake actuator 24 is, for example, AB
An S actuator is used. In this induction,
The vehicle uses the creep condition to achieve an extremely low speed (1-2 Km /
The movement of h) is realized, and the vehicle speed obtained by measuring the vehicle speed pulse interval from the distance sensor 19 by the ECU 16 is used to control the brake hydraulic pressure to realize extremely low speed movement. .

The laser scanning device 15 is constructed, for example, as shown in FIG. The laser scanning device 15 generates a laser beam and emits and receives a laser beam.
The output laser light from the light emitting and receiving device 151 is reflected by the prism-shaped rotating mirror 152 and emitted toward the rear of the vehicle. Then, the laser light reflected by the predetermined reflection plate 25 is reflected by the rotary mirror 152 and received by the light emitting / receiving unit 151. By rotating the rotary mirror 152 by the motor 153, the laser light emitting direction Are scanned.

The light emitting and receiving device 152 detects the reception of the laser light reflected by the reflecting plate 25. Based on the time difference between the emission of the laser light and the reception of the laser light, the laser is detected by the distance measuring and motor driving device 154. The distance between the scanning device 15 and the reflection plate 25 is calculated. In this case, the motor 153 is step-driven in response to a predetermined clock pulse from the ECU 16, laser light is emitted in response to this clock pulse, and when the reflected laser light from the reflector 25 is received. The distance between the reflectors 25 and the motor 15
The azimuth is detected from the step angle of 3.

That is, it is assumed that the vehicle 12 is set in the garage 11 as shown in FIG. 4, and the reflection plates 251 and 252 for setting the reference positions are set on both sides of the entrance of the garage 11. When the laser light is reflected by the reflection plate 251 as the rotary mirror 152 of the laser scanning device 15 rotates, the reception of the reflected light is detected and the rotation of the rotary mirror 152 is stopped, for example, and the laser scanning is performed in this state. The distance L between the device 15 and the reflector 251 is measured. At the same time, the angle φ is detected from the step angle of the motor 153 at this time.

When the distance between the reflecting plates 251 and the azimuth angle φ are measured in this way, the rotating mirror 152 is rotated again by the motor 153 to scan the laser beam. When the reflected laser light of is received, the distance R and the azimuth angle θ between the reflectors 252 are again detected.
To measure. Then, based on the distances L and R thus measured and the azimuth angles φ and θ, the coordinates (Qx, Qy) of the vehicle 12 (the line connecting the reflection plates 251 and 252 of the garage 11 to the X axis is taken as the garage). The central axis of 11 is taken as the Y axis, and the attitude angle ξ of the central axis of the vehicle 12 is calculated.

When the vehicle 12 is set in the garage 11 as shown by the broken line in FIG. 5 (as shown in FIG. 15), the guide line is formed by combining two turning circles and a straight line. . This is obtained based on the Ackermann steering characteristic as shown in FIG. 6, and the relationship between the steering angle and the turning radius can be represented by a map as shown in FIG.

When guiding control is performed by using such a combination of two turning circles and a straight line, the relationship between the traveling time of the vehicle and the steering angle is as shown in FIG. The steering angles at points a to d are also shown in the figure as a to d, respectively. Therefore, it is considered to be a jerk induction.

In this embodiment, the steering wheel 17 is steered at a constant speed, and has guide paths A to D shown by the solid line in FIG. In this case, the relationship between the moving time and the steering angle is as shown in FIG.

In this embodiment, the steering is moved at a constant speed, and the analysis of such a steering operation is relatively easy. Not only the actuator of the embodiment but also other actuators,
For example, an actuator using hydraulic pressure can be easily realized.

The guided trajectory shown by the solid line in FIG. 5 bulges outward as compared with the stationary steering algorithm by the combination of the two turning circles and the straight line shown by the broken line in FIG. (A) AB, which corresponds to the movement of AB in FIG. The turning radius between A and B is
Since the steering angle is smaller, it is larger than the stationary type.

8A is a section in which the steering is operated at a constant speed from the center of the steering toward the first turning radius in the stationary steering algorithm. Point B in this figure is a point at which the steering is switched in the opposite direction, and points B to B ′ are sections in which the steering is turned at a constant speed toward the second turning radius in the stationary steering algorithm. Further, B'to C are sections where the second turn is being executed as it is, and C is a switching point for turning the steering toward the center. Further, C to C'represent a section in which the steering is operated at a constant speed toward neutral, and C'to D are a final straight section.

Here, points B'and C'are points automatically determined from points B and C if the operating speed of the steering actuator is determined.
However, points B and C are completely unknown points,
If the points B and C are not properly determined, the vehicle 12 cannot be accurately guided to the garage 11. Therefore, the means for determining the points B and C are important elements for guiding the garage by continuous steering.

As shown in the Ackermann steering characteristics shown in FIG. 6, when the steering is fixed when the vehicle 12 is moved at an extremely low speed such as garage entrance guidance, the rear wheel axle of the vehicle 12 is extended. It has a characteristic of moving along a turning circle having a turning center. This Ackermann steering characteristic was also applied to the stationary steering guidance. This characteristic can be applied to the vehicle coordinate estimation even when the steering is turned at a constant speed.

As shown in FIG. 9A, when the steering is turned at a constant speed with the vehicle speed set to an extremely low speed,
The vehicle moves along a trajectory that combines minute turning circles determined from Ackerman steering characteristics.

FIG. 9B shows one of these minute turning circles taken out and shown. From the two-wheel model of the Ackerman steering characteristic, the turning radius Ri is a function of the following angular velocity ω of the tire. Given in. Ri = Lw / tan (δo−ωTi) where Lw: vehicle wheel base δo: initial tire angle ω: tire steering angular velocity (steering speed divided by overall gear ratio) Ti: time.

Such a small turning circle is added and integrated from the state of the current position (Qxo, Qyo) and attitude angle ξo in FIG. 9A until the steering is turned to the maximum in the opposite direction. By doing so, the estimated coordinates (Qxt, Qyt) and the estimated posture angle ξt at the time when the steering becomes the maximum in the reverse direction are calculated from the current position and the current posture angle by the following formula.

[0035]

[Equation 2] The estimated X coordinate Qxt and the estimated attitude angle ξt thus obtained
When the second turn is started from (corresponding to B'calculated from B in FIG. 8A), that is, when the turn required to ride on the central axis of the garage 11 is executed, the turn shown in FIG. The radius Rt cannot be Rt = Qxt / (1-sinξt), which can be easily calculated geometrically by using the Ackermann steering characteristic.

At this time, since the steering is turned to the maximum in the reverse direction, Rt = Rmin (Rmin: minimum turning radius) must be satisfied.

As described above, the steering switching timing B determination algorithm can be executed by the processing shown in FIG. That is, first, in step 101, the steering is moved at a constant speed toward the first turn, and in step 102, the coordinates and attitude angle at the current position of the vehicle are obtained. Then, in step 103, an estimated coordinate and an estimated attitude angle when the steering is turned in the opposite direction from the present state to the maximum are obtained.

When the estimated coordinates and the estimated coordinates are obtained in this way, a turning radius Rt for placing the vehicle on the central axis of the garage is obtained in step 104, and this turning radius Rt and the minimum turning radius Rmin are compared in step 105. And Rt is Rmin
If it is determined to be larger, proceed to step 106,
The vehicle is controlled to move at an extremely low speed.

This control is repeatedly executed until it is judged in step 105 that Rt is equal to Rmin.
If it is determined in step 5 that Rt is at least equal to Rmin, the process proceeds to step 107, and processing for moving the steering toward the reverse maximum is performed, and the switching point B is determined by this processing.

Here, the means for obtaining the current coordinates of the vehicle 12 in step 102 may be measured by using the laser scanning device 15, but it is shown in FIG. 9 using the Ackermann steering characteristic. As described above, every time the vehicle speed pulse is input from the distance sensor 19 of the vehicle 12, the minute circular turning at that time may be calculated and calculated by the recurrence formula.

Next, the process of determining the switching point C for returning the steering to the center at a constant speed from the second turn will be described. Also in this process, the estimated posture angle ξ obtained by adding and integrating the minute circular turns as shown in FIG. 12 is used. This estimated attitude angle ξ is calculated by the following formula.

[0042]

[Equation 3] At this time, when the estimated posture angle ξ is 90 °, this vehicle can be directly placed on the central axis of the garage and can go straight to the back of the garage 11, and C ′ to D in FIG. The steering process can be executed.

FIG. 13 shows the flow of the determination processing of the switching point C. In step 201, the steering is fixed to the second turning radius. In this state, the current posture angle of the vehicle is obtained in step 202, and the estimated posture angle at the time when the steering wheel is returned to the center in this state is obtained in step 203.

In step 204, it is determined whether the estimated attitude angle ξ obtained in step 203 is 90 °. If the estimated attitude angle ξ is not 90 °, the process proceeds to step 205 to control the vehicle at an extremely low speed. To do. If the estimated attitude angle ξ is determined to be 90 ° in step 205 by continuing the second turn in such a state, the process proceeds to step 206 and the steering wheel is moved toward the center at a constant speed, and this process is executed. Will be terminated.

FIG. 14 shows the flow of the whole processing.
The first step 301 is to set the vehicle to a stop and then step 302
Measure the coordinates of this initial state in step 303
Move around the steering with. In step 304, the brake of the vehicle is released, and in step 305, it is determined whether or not the current position is the switching point B. Further, in the next step 306, it is determined whether or not it is the switching point C.

In the processing of steps 305 and 306, the processing shown in FIG. 11 and the processing shown in FIG. 13 are executed. By executing such processing, the vehicle is not stopped on the way. , Smooth garage guidance will be realized. Further, when it is desired to cancel such guidance on the way, the switch 26 may be operated to interrupt the ECU 16 so that the guidance cancellation process is performed.

In the garage guidance system for a vehicle according to the above-described embodiment, the guidance route is formed by two circular turns and a straight line. For example, it is possible to guide by continuous steering to all other conceivable combination routes, such as a line that makes one round turn and a straight line, or a line that makes one round turn and then goes straight. .

Further, it is possible to guide the garage to a 4WS vehicle in the same manner. In case of 4WS car, normal 2
Unlike the WS car, in the extremely low speed running state, the center of the rear wheel axis extension does not make a circular turn, but the turning center is determined by the angle formed by the front wheel and the rear wheel, but the center of the circular turn deviates. By combining the minute circular turns in the state, it is possible to estimate the coordinates and the attitude angle, and thus the guidance can be similarly performed only by changing the calculation formula.

[0049]

As described above, in the garage guidance device for a vehicle according to the present invention, steering is continuously performed without performing stop and stationary operations, which requires a considerably long time loss when guiding the garage. It is possible to guide the vehicle into a predetermined garage by steering the vehicle so that smooth garage guidance operation can be performed without giving the driver a sense of abnormality and minimizing time loss. become.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a vehicle used in a garage guidance device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an electronic control unit mounted on the vehicle.

FIG. 3 is a configuration diagram illustrating a laser scanning device that is also mounted on a vehicle.

FIG. 4 is a diagram for explaining coordinate measuring means using this laser scanning device.

FIG. 5 is a diagram illustrating a garage guidance route.

FIG. 6 is a diagram illustrating Ackerman steering characteristics.

FIG. 7 is a diagram illustrating a relationship between a turning radius and a steering angle.

8A and 8B are diagrams showing steering operation states corresponding to the guide lines of the device according to the embodiment and the conventional device, respectively.

FIG. 9A is a diagram for explaining a coordinate estimating means utilizing Ackermann steering characteristics, and FIG. 9B is a diagram showing one of the turning circles taken out.

FIG. 10 is a diagram illustrating realization of a second turning radius.

FIG. 11 is a flowchart illustrating a switching point determination process for entering a second turn.

FIG. 12 is a view for explaining coordinate estimation for riding on the garage center axis line.

FIG. 13 is a flowchart illustrating a determination process of a switching point on the garage center axis line.

FIG. 14 is a flowchart illustrating the flow of overall guidance processing.

FIG. 15 is a diagram illustrating a conventional garage guidance route.

[Explanation of symbols]

11 ... Garage, 12 ... Vehicle, 15 ... Laser scanning device, 16 ... Electronic control unit, 17 ... Steering, 18 ... Steering sensor, 19 ... Distance sensor, 20 ... CRT controller, 21 ...
CRT, 22 ... Steering driver, 23 ... Steering actuator, 24 ... Brake actuator.

Claims (1)

[Claims] 1. A coordinate measuring means for measuring coordinates and a posture angle of a vehicle with respect to a garage, a steering steering means for automatically steering a steering wheel, a steering angle detecting means for detecting a steering angle of the steering wheel, Guide line setting means for obtaining a guide line to be placed on the central axis of the garage based on coordinates and attitude angle; and first steering control means for steering the steering at a constant speed toward the first turn of the guide line. In the control state of the first steering control means, first current coordinate calculation means for obtaining the current coordinate arrangement posture angle of the vehicle based on the continuously changing steering angle and vehicle travel distance; A first coordinate estimating means for obtaining an estimated coordinate and an estimated attitude angle when the steering is steered in the reverse direction on the basis of the current coordinate and the attitude angle; The final turning radius calculation means for finding a turning radius for the vehicle to ride on the central axis of the garage based on the coordinates and the attitude angle estimated by the above, and the obtained final turning radius and the minimum turning radius of the vehicle are compared. However, in a state where the final turning radius is determined to be equal to or greater than the minimum turning radius, the first turning traveling means that runs the vehicle at an extremely low speed by the first steering control means, and the obtained final turning radius. A second steering which compares the minimum turning radius of the vehicle and steers the steering wheel in the opposite direction at maximum at a constant speed in a state where it is determined that the final turning radius is equal to or less than the minimum turning radius. Control means, and second current coordinate calculation means for obtaining a current attitude angle of the vehicle based on the steering angle and the vehicle travel distance that continuously change under the control state of the second steering control means; Zodiac Second coordinate estimating means for obtaining an estimated posture angle when the steering wheel is returned to the center based on the current posture angle calculated by the calculating means, and the estimated posture angle obtained by the second coordinate estimating means. Is the second turning traveling means that travels at an extremely low speed until the vehicle is in a state of riding on the garage center axis line, and the estimated posture angle obtained by the second coordinate estimating means is the vehicle at the garage center. A garage guidance device for a vehicle, comprising: a third steering control unit that steers the steering wheel toward the center while riding on an axis.