JPH03189805A - Method and device for automatic steering vehicle - Google Patents

Abstract

PURPOSE:To simplify the guidance control of a vehicle, and also, to execute it with high accuracy by deriving a position deviation and an azimuth deviation of a target set course and the actual position and azimuth of the vehicle, setting the linear coupling of those position deviation and azimuth deviation as a steering angle and executing the steering angle control of the vehicle. CONSTITUTION:In the case a vehicle deviates from a set course, a position deviation D and an azimuth deviation DELTAtheta of the present spot and the set course in that case are detected, and by setting the sum (=K1.AD+K2.DELTAtheta) of a value (K1.AD) and (K2.DELTAtheta) obtained by multiplying the position deviation D and the azimuth deviation DELTAtheta by prescribed coefficients K1, K2 as a steering angle, the vehicle is run. In such a way, the processing for correcting the vehicle from the shifted spot to the set course is obtained by a simple arithmetic processing, and also, the free correction can be executed with high accuracy.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an automatic steering method for quickly guiding a vehicle along a set course from a current point to another destination point, and an automatic steering method using the method. Regarding equipment.

[Prior Art] Conventionally, this type of automatic steering method has been disclosed in Japanese Patent Application Laid-open No. 59-1.
There is one disclosed in No. 11508.

This conventional technology sets an appropriate number of target points between the vehicle's current location and the destination point, and connects the vehicle's current location and the target location with a cubic curve when the vehicle deviates from the set course. Then, calculate the steering angle for traveling on the cubic curve, make the vehicle travel for a unit time with that steering angle, and then set the vehicle position after traveling for the unit time as the current location, and calculate the current location and the above purpose. The vehicle is again connected to the point by a cubic curve, the steering angle for traveling on the cubic curve is calculated, and the vehicle is made to travel for a unit time again at that steering angle.

Then, the process of calculating a new steering angle every time the vehicle travels for a unit time is repeated until the vehicle reaches the destination, thereby attempting to guide the vehicle to the destination. ... [Problem to be solved by the invention] However, in such conventional automatic guidance methods, it is difficult to set an appropriate number of target points between the current location of the vehicle and the destination location. There was a problem.

In other words, in order to match the actual driving course of the vehicle with the set course as much as possible, it is necessary to set a large number of target points at a high density between the vehicle's current location and the final destination point. The problem was that it was extremely complicated.

In addition, regarding the setting of target points between the vehicle's current location and the final destination point, there is no method disclosed for setting the optimal number of target points depending on the course, so it is difficult to determine the optimal number of target points by relying on intuition. There was a problem that I had to set it up.

The present invention has been made in view of such problems,
It is an object of the present invention to provide an automatic steering method for a vehicle that can further simplify and improve the accuracy of guidance control of a vehicle, and an automatic steering device to which the method is applied.

[Means for Solving the Problem] In order to achieve such an object, the present invention detects the position deviation and azimuth deviation Δθ between the current location and the set course when the vehicle deviates from the set course. Then, the sum of (Kl・ΔD) and (K2・Δθ) (=
The vehicle was run with the steering angle α set to 1·D+2·Δθ).

Further, an automatic steering device according to this method is provided with a direction measuring means, a distance measuring means, and a storage means for storing data of a set course in advance, and also capable of measuring the direction and distance outputted from the direction measuring means and the distance measuring means. Calculating means is provided for determining the positional deviation and azimuth deviation from the data, multiplying these data by a predetermined coefficient, and performing an addition operation to determine the steering angle.

[Operation] In the present invention using such a method and device, the process for correcting the vehicle from the deviated point to the set course is performed by:
This can be realized with extremely simple arithmetic processing and a device for arithmetic processing, and automatic correction can be performed with high precision.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

First, FIG. 1 shows the configuration of an automatic steering system based on the steering method of the present invention. In FIG. 1, the automatic steering bag W1 includes a direction measuring means 2 for sequentially measuring the traveling direction θ of the vehicle, a distance measuring means 3 for sequentially measuring the traveling distance 1, and data on a set course on which the vehicle should travel in advance. It is equipped with a storage means 4 for storing information, and uses, for example, a gyro as the direction measuring means 2,
As the distance measuring means 3, for example, an encoder is used which measures the traveling distance by counting the number of rotations of the wheels.

It also has a storage means 4 for pre-storing data on the course of the vehicle, that is, a set course, and includes a read-only memory (ROM) and a random access memory (RAM) in which data on the set course can be rewritten via an interface (not shown).
).

Furthermore, it is equipped with a calculation means 5 consisting of a microprocessor, etc., which inputs the actual measurement data from the direction measurement means 2 and the distance measurement means 3, and compares the actual measurement data with the data of the set course stored in the storage means 4. By doing this, the deviation from the set course of the vehicle, that is, position deviation and azimuth deviation Δ
θ is calculated, and further, these position deviations and azimuth deviations Δθ
By performing a predetermined calculation, which will be described later, on the steering angle α, a steering angle α of the vehicle for correcting the deviation in the vehicle position is calculated, and data on the steering angle α is output to a steering mechanism (not shown).

Next, the operation of the automatic steering system 1 having such a configuration will be explained.

As shown in Fig. 2, the vehicle 6 is assumed to move in the XY coordinate system, and the motion of the vehicle 6 is expressed by equations (1) to (3)% () (2) where d x / d t is dy/dt is the change in unit time in the X direction, dy/dt is the change in unit time in the Y direction, L is the distance between the front and rear wheels, θ is the direction of the vehicle, and α is the advancing angle of the front wheels, that is, the steering angle.

In this embodiment, the steering angle of the wheels is set according to the steering angle α calculated by the calculation means 5, and when the vehicle deviates from the set course, the steering angle α is set to allow the vehicle to return to the set course. This is what we are trying to achieve.

For example, as shown in Fig. 3, when a positional deviation of D and an azimuth deviation of Δθ are detected from the vehicle's set course (assumed to be on the X-axis in the figure), the steering wheel to be controlled The angle α is determined by a linear combination of the positional deviation and the azimuth deviation Δθ according to the following equation (4).

α=1・ΔD+2・Δθ (4) Here, the coefficients 1 and 2 are set to appropriate values.

Next, the principle of returning the vehicle 6 to the set course by steering the front wheels of the vehicle 6 in the direction of the steering angle α determined by the calculation process of equation (4) above will be explained.

The setting course is now set to match the X axis.

Therefore, the positional deviation is the Y-axis value, and the azimuth deviation Δθ is θ
It can be made equivalent to the above formula (2) %Formula%() (5) If θ is small, the above formula (5) becomes D dt =V・θ... (6) Become.

Also, assuming that the rudder angle α is small, the above formula (3)% formula%
(7) becomes. Furthermore, by substituting the above equation (4) into the above equation (7), do −2 (2・θ for Kl・D+) ... (8) d
t L , and further convert the above equation (8) into a constant vehicle speed V (v=
const), the above equation (6
), we get 2 dt L
dt... (9) Since the above equation (9) is a second-order differential equation, for coefficients 1 and 2, K1 × 0, K2 <0
If set to a value that satisfies the condition, θ oscillates or decays exponentially and converges to zero.

Therefore, depending on the size of the vehicle to be controlled, the optimum coefficients 1 and 2 are set in advance, and the calculation means 5 in FIG. By performing calculation processing, it is possible to determine the optimal steering angle α, and by controlling the vehicle based on this steering angle α, it is possible to completely automate the return of the vehicle to the set course. becomes.

FIG. 4 shows simulation results when a vehicle is controlled based on this principle. In other words, as a specific numerical value,
Vehicle speed is v=50cm/see, initial direction deviation Δθ
= 10°, initial position deviation D = 10cm, 1 = -0,0
2. This is the case where K2=-5 and the distance L between the front and rear wheels is set to 100 cm.

Further, FIG. 5 shows other simulation results when a vehicle is controlled based on this principle. That is, as specific numerical values, the vehicle speed is v = 50 cm/5ec1, initial azimuth deviation Δθ = -10°, initial position deviation D = 20 cm,
1=-0,02, K2=-5, distance between front and rear wheels L=10
This is the case where it is set to 0 cm.

As is clear from these simulation results, even if the vehicle deviates in a positive direction or a negative direction with respect to the traveling direction (X-axis direction) of the set course, it can be smoothly returned to the set course.

In this simulation, a limit is set at α=±45° in accordance with the actual steering angle of the vehicle. That is, the steering angle α signal outputted from the calculation means 5 in FIG.
8, when the steering angle α has a value outside the range of -45″<α<+45°, the steering angle α is set to αmat.

Next, a method for changing the course of a vehicle by using the automatic steering method according to the present invention will be explained with reference to FIG.

It is assumed that in the 61st ffl, the target point for changing course is P, and the vehicle advances from point 8 to point T. Here, the first
Assuming that the coordinates of the passing target point S are (Xi, Yl), the coordinates of the course change target point S are (X2.Y2), and the coordinates of the second passing target point T are (X3.Y3), the calculation process Means 5
The direction of travel is controlled by processing the following arithmetic expressions.

First, the set course L1 connecting points S and P is calculated by the following formula (% formula %) Similarly, the set course L2 connecting points P and T is calculated by the following formula (11
).

Then, when the vehicle travels on the set course Ll from point S and enters within a certain distance R from point P, steering control is performed to change the course to the set course 2.

That is, before entering a certain distance R from point P, the set course L
The position error and azimuth error Δθ when traveling on l are, however, in the above formula (13), Al= Y2-YI 2-Xi B1-1, (:l-Yl-YI 2-Xi ・X1-YJ-, φ is the current orientation of the vehicle, and (x, y) are the current coordinates.

Then, by substituting the above equations (12) and (13) into the above equation (4), the steering angle α is determined and the course of the vehicle is controlled.

Furthermore, when the vehicle enters within the range of distance R from point P, that is, when the relationship R-X-X2 + (Y-Y2'≧0 holds true), control is performed to change the set course from L] to B2. conduct.

The orientation error Δθ and position error at this position are Δθ=φ−
tan-I Y3-Y2 ... (14) 3-X2 However, in the above formula (15), A 2 == Y 3 Y 2 B 2 =
= 1, 3-X2 C2-Y3-Y2 .X2-Y2 3-X2, φ is the current direction of the vehicle, and (x, y) are the current coordinates.

Then, by substituting the above equations (14) and (15) into the above equation (4), the steering angle α is determined and the course of the vehicle is controlled.

In this way, according to the steering angle control method of the present invention, it is also possible to change the traveling direction of the vehicle.

[Effects of the Invention] As explained above, according to the present invention, the positional deviation and azimuth deviation between the target set course and the actual position and azimuth of the vehicle are determined, and a linear combination of the positional deviation and azimuth deviation is calculated. Since the steering angle of the vehicle is controlled using the steering angle as the steering angle, the control becomes extremely simple and it is possible to realize complete automatic control with high precision.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of an embodiment of the steering angle control device according to the present invention, FIG. 2 is an explanatory diagram for explaining the operation of the embodiment, and FIG. 3 is a detailed diagram of the present invention. FIG. 4 and FIG. 5 are explanatory diagrams showing the simulation results of the operation of the embodiment. FIG. 6 is an explanatory diagram when the traveling direction of the vehicle is changed according to the steering control according to the present invention. . Symbols in the figure: 1; Automatic steering device 2; Direction measuring means 3; Distance measuring means 4; Storage means 5; Calculating means 6; Vehicle S/first passing target point P; Course change target point T; Second passing target point

Claims (2)

[Claims] (1) Arithmetic processing of output signals output from a direction measuring means for measuring the running direction of the vehicle, a distance measuring means for measuring the distance traveled by the vehicle, and a storage means for storing data of a preset set course In a vehicle automatic steering method for controlling a vehicle to follow a set course by , find a positional deviation between the positional data of the set course stored in the storage means and the actual measurement value output from the distance measuring means, and control the steering angle of the vehicle according to the value of the linear combination of the azimuth deviation and the positional deviation. An automatic vehicle steering method characterized by: (2) In an automatic steering system for a vehicle that controls the vehicle to follow a preset set course, a direction measuring means for measuring the traveling direction of the vehicle, a distance measuring means for measuring the traveling distance of the vehicle, and a distance measuring means for measuring the traveling distance of the vehicle; a storage means for storing the data of the set course that has been set; and an azimuth deviation between the azimuth data of the set course stored in the storage means and the actual measured value output from the azimuth measurement means, and the azimuth deviation stored in the storage means. It is characterized by comprising calculation means for calculating the positional deviation between the positional data of the set course and the actual measurement value output from the distance measuring means, and controlling the steering angle of the vehicle according to a value of a linear combination of the azimuth deviation and the positional deviation. Automatic steering system for vehicles.