JP3012651B2 - Driving / steering control method for omnidirectional vehicles - Google Patents

Description

The present invention relates to a traveling / steering control method for an omnidirectional vehicle.

[Conventional technology]

2. Description of the Related Art Conventionally, as disclosed in, for example, JP-A-59-92262, an omnidirectional vehicle having, for example, four steerable wheels and capable of running in respective modes of an omnidirectional mode, an automobile mode, and a turning mode. It has been known. Here, the omnidirectional mode is a mode in which all the wheels run in the same direction as shown in FIG. 9, and the vehicle can run without changing the vehicle center line. In the vehicle mode, as shown in FIG. 10, the vehicle can turn while changing the center line of the vehicle body in the same manner as a normal vehicle. Further, the turning mode refers to a mode in which the vehicle can rotate around the turning center CO by directing the axial lines of all the wheels toward the turning center as shown in FIG.

In such an omnidirectional vehicle, to switch to the omnidirectional mode, the vehicle mode, and the turning mode, for example, as disclosed in the above-mentioned publication, after aligning the directions of all the wheels, disengage them by operating the clutch and switch the wheels to the angular mode. I was Therefore, of course, when the vehicle is moving in a certain traveling direction of the vehicle body in the omnidirectional mode, for example, when the vehicle is traveling in a constant traveling direction line in the omnidirectional mode, for example, an impact such as an inclination of a road surface, over unevenness, or the like.
When the traveling direction line of the vehicle body deviates from the intended direction due to other external forces, and when you want to change the traveling direction line while traveling in the omnidirectional mode, it is necessary to stop and then change direction. there were.

According to the present invention, virtual steering wheels are provided, and the movement of all the wheels is replaced with one of the virtual steering wheels, and the virtual steering wheels are provided with a traveling angle β, a steering angle α,
Operated by the command signal of the speed information γ, and by controlling the running of all wheels based on this virtual steered wheel, the deviation of the traveling direction line of the moving body in the omnidirectional mode and the change of the traveling direction line are stopped. The purpose is to provide a directional control of traveling and steering of an omnidirectional vehicle that can be performed without the need for a vehicle.

[Means for solving the problem]

The invention of claim 1 relates to a traveling / steering control method for an omnidirectional vehicle, comprising: a vehicle traveling at an advancing angle β with respect to a vertical axis Y which is a direction of a vehicle centerline of coordinates having a representative point of the vehicle as an origin. A virtual steering wheel (5) is imagined at a position on the direction line Q and at a distance n from the origin O, and the steering angle which is a steering angle of the virtual steering wheel with respect to the traveling direction line Q of the vehicle body together with the traveling angle β. α is given as a command signal to the virtual steered wheel (5), and a straight line R perpendicular to the travel direction Q and passing through the origin O intersects the extended line T of the axis of the virtual steered wheel. The turning center C is set at the intersection, and the traveling angle β given to the virtual steered wheel (5)
A steering angle α and a driving speed V which are calculated around the turning center C and controlled by a command signal of a steering angle α and speed information γ representing a running speed of the virtual steered wheels. It is characterized by doing.

In the invention of claim 2, the control of the driving speed is performed on the drive wheels that can be driven among all the existing wheels,
The driving wheel is mounted with an offset f1 with respect to the steering shaft center S, and the driving speed V of the driving wheel is determined by the distance d between the steering shaft center S and the turning center C of the driving wheel and the offset amount. It is a value obtained by multiplying the ratio (d + f1) / L of the distance L from the turning center C to the virtual steered wheel to the sum (d + f1) of f1 and the speed information γ of the virtual steered wheel.

The invention according to claim 3 is characterized in that the steering angles U of the existing real wheels are set such that the axial lines of all the wheels cross each other at the turning center C.

[Action]

All wheels are formed so as to be independently steerable, and, for example, when a driver operates a command device installed on the vehicle body, a traveling angle β to be traveled, a steering angle α, and a speed information γ Generate command signal. This command signal is supplied to, for example, an appropriate arithmetic and control unit, and the device uses the command information of the advancing angle β to represent a representative point of the vehicle body, for example, a vertical axis Y (vehicle center line) of coordinates having the origin at the center point of the vehicle body. A traveling direction line Q of the vehicle body that forms a traveling angle β with respect to is set. In addition, the apparatus virtually simulates a virtual steered wheel 5 at a position on the traveling direction line Q and at a constant radial distance n from the origin. The steering angle α instructs the steering angle of the virtual steered wheel 5 with respect to the traveling direction line Q. The speed information γ commands the traveling speed of the virtual steered wheels.

In order to control the steering angle U and the driving speed V of the actual wheels, first, a traveling direction perpendicular line R perpendicular to the traveling direction line Q and passing through the origin and an axis extension line T of the virtual steered wheels are formed. The turning center C is set as an intersection. By calculating around the turning center C, the steering angle U and the driving speed C of the actual wheels can be controlled.

More specifically, the control of the drive speed V is performed on the drive wheels that can be driven among all the existing wheels, as described in claim 2. Also, this drive wheel is the steering shaft center S.
Assuming that the drive wheel is mounted offset by an offset amount f1, the drive speed V of the drive wheel is determined by the distance d to the steering shaft center S of the drive wheel and the offset amount.
Control is performed as a value obtained by multiplying the ratio (d + f1) / L of the distance L from the turning center C to the virtual steered wheel to the sum (d + f1) of f1 and the virtual steered wheel speed information γ.

The steering angle U is controlled by setting the axial lines W of all the wheels so as to intersect each other at the turning center C for all the existing wheels.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 schematically shows the whole of the omnidirectional vehicle.
Wheels 1A, 1B, 1C, 1D in the corners (collectively called wheels 1)
Has been arranged. Also, all wheels 1 can be steered independently. The wheels 1A and 1B are drive wheels 1S and 1S that can be driven among all the wheels. Further, all the wheels 1 are mounted offset by an offset amount f1 with respect to the steering shaft center S. It should be noted that the steering or drive mechanism of the offset wheel is well known, for example, in Japanese Patent Application Laid-Open No. 59-92262.

A command device 3 and an arithmetic and control unit 4 can be mounted on the vehicle body 2. The command device 3 can generate command information of a traveling angle β shown in FIG. 2, generate command information of a steering angle α, and further generate command information of speed information γ by an operation of an operator. Here, the advancing angle β is a representative point of the vehicle body, for example, a Y-axis (vehicle center line) having a center point O as an origin O.
With respect to the traveling direction line Q of the vehicle body 2. Also, counterclockwise is defined as positive.

This command information is given to the arithmetic and control unit 3, and the device 3 receives the command information of the advancing angle β and sets the virtual steering wheel at a position on the advancing direction line Q of the vehicle body and at a certain radial distance n from the origin. 5 is assumed. In addition, the device 3 stores the arrangement of all the actual wheels 1 together with the setting of the virtual steered wheels 5, and can display the arrangement on the display if necessary.

Further, the steering angle α refers to the steering angle of the virtual steered wheel 5 with respect to the traveling direction line Q of the vehicle body 2, and the counterclockwise direction is defined as positive. The speed information γ commands the traveling speed of the virtual steered wheels.

As described above, the command device 3 generates both the traveling angle β, the steering angle α, and the speed information γ in the omnidirectional mode of the traveling angle β and in the omnidirectional mode while traveling at the speed based on the speed information γ. Is turned in the vehicle mode at the steering angle α with the direction of the center line as the center line. Note that the steering angle α
Is 0, indicating that the vehicle is traveling in the omnidirectional mode, and that the traveling angle β is 0 indicates that the vehicle is traveling straight ahead. The turning mode at the steering angle α can be set according to the command information of the operator. Further, the traveling angle β is 0 and the steering angle α and the speed information γ
Can be run in a so-called automobile mode. All the wheels 1 are steered by rolling around a vertical steering center axis S.

Further, the arithmetic and control unit 3 obtains
As described below, the steering angle U of all the actual wheels 1 is controlled, and the driving speed V of the driving wheels is controlled. Here, a description will be given mainly of, for example, a wheel 1A (a drive wheel 1S) that can be driven and steered.

In FIG. 2, the coordinates of a vertical axis Y in the vehicle body center line direction with the center point of the vehicle body as the origin O and a horizontal axis X passing through the origin O are set in the vehicle body. In addition, a traveling direction line Q of the vehicle body is defined as a vertical axis y,
A second coordinate (x, y) having a horizontal axis x and a vertical line R perpendicular to the traveling direction line Q (vertical axis y) and passing through the origin O is considered. The vertical axis y forms an angle of advance with the vertical axis Y as the advance angle β. Therefore, the second coordinate (x,
y) rotates with respect to coordinates (X, Y).

The virtual steering wheel 5 is on the vertical axis y, and a turning center C is set at an intersection of the horizontal axis x, that is, the perpendicular line R of the traveling direction and the axis extension line T of the virtual steering wheel 5.

The processing procedure will be described with reference to the flowchart of FIG. 3 assuming that the position of the actual steering wheel center S of the wheel 1A in the XY coordinates is (m1, m2). Let n be the distance of the virtual steered wheel 5 from the origin O on the y-axis (the traveling direction line Q of the vehicle body).
And This value can be set by trial in consideration of the actual wheel arrangement so that good control is possible.

First, as a first processing procedure S1, the coordinates (m1, m2) at the coordinates (X, Y) of the steering axis center S of the wheel 1A are
The coordinates are converted to the coordinates (a, b) of the steering axis center S of the wheel 1A at the second coordinates (x, y). The coordinate transformation is as follows (1)
It is determined by the formula.

That is, a = m1 × cos (β) + m2 × sin (β) b = m2 × cos (β) −m1 × sin (β) (1) As the second processing procedure S2, the steering axis of the actual wheel 1A is obtained. The vertical line from the center S to the horizontal axis (x) is the horizontal axis (x).
Can be obtained from the following equation (2) from the intersection point A intersecting to the turning center C.

c = n / tan (α) + a (2) Note that α = π / 2, and thus the axis extension line T of the virtual steered wheel 5
Is coincident with the vertical axis y, it is clear that c = −a in the equation (2).

As a third processing procedure S3, the distance d on the line (SC) between the steering axis center S and the turning center C of the actual wheel 1A is obtained by the following equation (3).

As a fourth processing procedure S4, an angle U1 formed by the center S of the steering wheel of the actual wheel 1, the turning center C, and the origin O of the vehicle body is obtained by the following equations (4-1) to (4-3). The line (SC) connecting the steering shaft center S and the turning center C is the axial line W of the actual wheel, and (4-1) to (4-3) are the axial lines W of the wheels. The directions are set so as to cross each other at the turning center C.

I) When α> 0 When b> 0 U1 = cos ⁻¹ (c / d) When b ≦ 0 U1 = −cos ⁻¹ (c / d) (case of FIG. 4) (4-1) However, when d = 0, that is, when c and b are both 0, in other words, when the actual wheel 1A comes to the turning center C as shown in FIG. 5, c / d becomes indefinite, so that U1 = π / 2 It is determined.

II) When α <0 When b> 0, U1 = −cos ⁻¹ (c / d) (FIG. 6) When b ≦ 0, U1 = cos ⁻¹ (c / d) (FIG. 7) Case) (4-2) However, when d = 0, that is, when c and b are both 0, in other words, when the actual vehicle body 1A comes to the turning center C as shown in FIG. 8, c / d becomes indefinite. Therefore, U1 is set to −π / 2.

III) When α = 0, the turning center C is at infinity. In other words, the fact that the steering angle α is 0 is only the traveling angle β, that is, the vehicle is traveling in the omnidirectional mode with the traveling angle β. Therefore, the wheel is in the y-axis direction (the direction of the virtual steered wheels).
Suitable for That is, U1 = 0 (4-3) As the fifth processing procedure S5, the drive speed V of the drive wheel is obtained from the following equations (5-1) to (5-2). The distance L from the turning center C to the virtual steering wheel is n / sin (α), and when α> 0, V = γ × (d + f1) / L = γ × (d + f1) × sin (α) / n When α <0 V = γ × (d−f1) / L = γ × (d−f1) × sin (−α) /
n (5-1) When α = 0, the turning center C is at infinity. In other words, the fact that the steering angle α is 0 is only the traveling angle β, that is, the vehicle is traveling in the omnidirectional mode with the traveling angle β.
Therefore, the wheels are oriented in the y-axis direction (the direction of the virtual steered wheels). That is, it becomes equal to the speed information γ of virtual steering =.

 V = γ (5-2) This processing procedure S5 is performed only for the drive wheel 1S.

It is apparent that the steering angle U of the wheel 1A is obtained by the following equation (6) as the sixth processing procedure S6.

U = U1 + β (6) Such a processing procedure is automatically calculated for each wheel to control each wheel. As a result, the steering angles U of all the wheels and the traveling speed V of the drive wheels can be set for each wheel, and are calculated and controlled. Further, by giving the steering angle α while giving the traveling angle β, it is possible to change and steer the traveling direction line Q in the omnidirectional mode.

〔The invention's effect〕

The method of the present invention calculates the steering angle and drive speed of each actual wheel by calculating based on command information given to virtual steered wheels, and controls traveling and steering of an omnidirectional vehicle while controlling each wheel. Therefore, for example, when the external force acts on the omnidirectional vehicle in the running state in the omnidirectional mode, the omnidirectional vehicle rotates, and even if the body angle is shifted, the steering angle is corrected without stopping. You can run. Therefore, it is possible to accurately lay the station on a station or the like, and the effect of improving the cargo handling efficiency is produced.

[Brief description of the drawings]

1 is a diagram illustrating an omnidirectional vehicle used in the method of the present invention, FIG. 2 is a diagram illustrating the principle illustrating the method of the present invention, FIG. 3 is a flowchart of the method of the present invention, 4 ~
FIG. 8 is another diagram for explaining the principle, and FIGS. 9 to 11 are diagrams for explaining the traveling mode. 1, 1A, 1B, 1C, 1D ... wheels, 1S ... drive wheels, 2 ... body, 5 ... virtual steered wheels, α ... steering angle, β ... travel angle, γ
... Speed information, U ... Steering angle, V ... Drive speed.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinobu Tanaka 2-1-1, Higashikami-shi, Nagaokakyo-shi, Kyoto Referee, Japan Transport Aircraft Co., Ltd. JP-A-61-218459 (JP, A) JP-A-60-58481 (JP, U) JP-A-61-87779 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B62D 7/14

Claims (3)

(57) [Claims] 1. A traveling / steering control method for an omnidirectional vehicle in which all wheels are steerable and all wheels are able to travel in the same direction, comprising: a vehicle center line having a coordinate originating from a representative point of the vehicle. A virtual steered wheel (5) at a position on the traveling direction line Q of the vehicle body forming a traveling angle β with respect to the longitudinal axis Y and at a distance n from the origin O.
And a steering angle α, which is a steering angle of a virtual steered wheel with respect to the traveling direction line Q of the vehicle body, is given to the virtual steered wheel (5) as a command signal together with the traveling angle β. A turning center C is set at an intersection of a traveling direction perpendicular line R passing through the origin O and a right angle with Q, and the virtual steering wheel is provided to the virtual steering wheel (5). Advancing angle β,
Controlling the steering angle U and the driving speed V of the actual wheels by calculating around the turning center C by a command signal of a steering angle α and speed information γ representing a running speed of the virtual steered wheels. A traveling / steering control method for an omnidirectional vehicle, characterized in that: 2. The driving speed control is performed on driving wheels that can be driven among all the actual wheels, and the driving wheels are mounted with an offset amount f1 with respect to a steering shaft center S. The driving speed V of the driving wheel is a distance L from the turning center C to the virtual steering wheel with respect to the sum (d + f1) of the distance d between the steering shaft center S and the turning center C of the driving wheel and the offset amount f1. Ratio (d + f1)
2. The traveling / steering control method for an omnidirectional vehicle according to claim 1, wherein the value is obtained by multiplying / L by virtual speed information γ of the steered wheels. 3. The omnidirectional vehicle according to claim 1, wherein the steering angle U is set so that the axial lines of all the wheels cross each other at the turning center C. Driving / steering control method.