JPH1195840A - Method for correcting error of steering zero adjustment information of gyro guide type automated guided vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct the deviation angle of zero adjustment information of steering during an automatic travel by measuring the position shifted amount of a travel- directional front control point and correcting the truck position and attitude angle, and then measuring the shifted amount of a rear control point and finding the deviation angle of steering zero adjustment information on the travel-directional front side. SOLUTION: When steering zero adjustment information before a travel has a deviation angle, the truck 5 travels obliquely by the deviation angle Δα, so the shifted amount at the travel-directional front control point is measured by a magnetic sensor on a front side and the error Δyr between an estimated truck position and the actual truck position is considered to result from the attitude angle error of the truck and is then corrected. Consequently, the position shift quantity at the travel-directional front control point is eliminated and the shifted amount is obtained only at the travel- directional rear control point, so the position shift quantity at the travel-directional rear control point is detected by a rear-side magnetic sensor to find the deviation angle Δα of travel-directional front steering zero adjustment. Then the travel- directional front steering angle is corrected by using the deviation angle Δα.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a guidance system for a two-wheel independent steering type automatic guided vehicle equipped with a bogie attitude angle detection sensor (gyro), a traveling distance detection sensor and a steering angle detection sensor (hereinafter referred to as a "gyro guidance system"). )), Which relates to a method of correcting the deviation angle of the steering null information during automatic traveling. It should be noted that the steering zero adjustment information means that when the steering angle is 0, the ABS encoder is turned off.
It refers to the angle indicated by da.

[0002]

2. Description of the Related Art Currently, various guided systems such as an electromagnetic induction system and a magnetic induction system are used for automatic guided vehicles. However, most of these methods require processing for installation of a guide wire on the floor surface, and the layout cannot be easily changed. On the other hand, the guidance system using the gyro has an advantage that the layout can be easily changed by merely providing the correction points intermittently and without requiring the installation of the guidance lines.

FIG. 1 shows an example of a gyro-guided system configuration of a front and rear two-wheel independent steering automatic guided vehicle. The basic guidance system is as follows. (1) The bogie attitude angle is measured by a gyro, the running distance of the driving wheels before and after the bogie is measured before and after by a pulse integrated value of a running pulse generator that increases in proportion to the running distance, and the steering angle of the steering wheel is measured. The front and rear steering encoders (ABS encoders) measure the front and rear, respectively.

(2) The travel of the bogie from the travel distance Δl, the current bogie attitude angle φ, and the current front steer steering angle α in the running direction, which is measured by the movement distance Δl of the front driving wheel in the running direction during an arbitrary time interval Δt. The movement amounts Δx and Δy of the front drive wheel during the time Δt are calculated by the calculator (see FIG. 2). Δx = Δlcos (φ + α) Δy = Δlsin (φ + α) Therefore, the position of the front drive wheel in the traveling direction is as follows. xfn = xfn-1 + Δx yfn = yfn−1 + Δy where (xfn, yfn) is the coordinates of the current drive wheel, and (xfn−
(1, yfn-1) is the coordinates of the drive wheel before Δt. The rear drive wheel position in the traveling direction is determined by the following equation from a hard positional relationship. xrn = xfn-Lcosφ yrn = yfn + Lsinφ Here, L is the distance between the front control point in the traveling direction and the rear control point in the traveling direction, for example, the distance between the centers of the magnetic sensors before and after the traveling direction.

(3) This is integrated by an arithmetic unit, and the current position of the carriage (point along the traveling path before and after the carriage) is obtained.
Calculates the amount of deviation from a predetermined travel path (corresponding to a guide line, which is internal data and has no substance), transmits a steering speed command to a steering driver, and performs a steering operation corresponding to this. To independently control the truck.

(4) In addition, since errors occur in position calculation and measurement, a magnetic marker (eg, a ferrite magnet) is installed at every interval on the guide line, and when passing over this, it is installed on a bogie. The positional deviation amount of the bogie is measured by the detected magnetic sensor on the front side in the traveling direction, and the error of the position and the posture angle of the bogie is calculated by a calculator and corrected.

[0007]

SUMMARY OF THE INVENTION According to the present invention, an error occurs in the measurement of a gyro-guided automatic guided vehicle which calculates a position of a bogie using measured values such as a traveling distance and a steering angle during automatic running by a gyro. It is therefore an object of the present invention to solve the problem that the accurate bogie position cannot be calculated, and to correct such an error of the measurement system, particularly the deviation angle of the zero-tuning information of the steering during the automatic traveling.

[0008]

Means for Solving the Problems During automatic driving by a gyro, a bogie position is calculated by an arithmetic unit using measured values such as a running distance measured by a running distance sensor and a steering angle of a steering measured by a steering angle sensor. In front and rear two-wheel independent steering gyro-guided automatic guided vehicle, the amount of displacement of the front control point in the traveling direction is measured, and after correcting the bogie position and attitude angle, the displacement of the rear control point in the traveling direction The deviation is measured, and the deviation angle of the steering zero adjustment information on the front side in the traveling direction is obtained from the positional deviation amount.

[0009]

Embodiments of the present invention will be described with reference to the drawings. FIG. 3 shows an example of a gyro induction type magnetic sensor arrangement. As shown in FIG. 3, the magnetic sensors 2a and 2b are mounted so that the center position of the magnetic sensors 2a and 2b is located at a point (control point) to be guided along the guide line (travel path). Need not be placed).

As shown in FIGS. 3 and 4, magnetic markers 4a and 4b are installed on the floor at arbitrary intervals. As a specific example, a magnetic sensor and a magnetic marker (ferrite magnet) are used for measuring the actual shift amount of the bogie position, but other measuring instruments that can intermittently measure the shift amount of the bogie position are used. But it doesn't matter.

In addition, the gyro 3 and a travel distance sensor (for example, a travel pulse generator)
), A steering angle sensor (for example, a steering encoder) and measurement values from these sensors are input,
As shown in FIG. 1, a computing unit (microcomputer, PC, etc.) for calculating the position of the bogie position and the deviation of the steering zero adjustment information and outputting a steering speed command to the steering driver is installed.

The procedure for determining the deviation angle of the steering zero-tone information will be described below. (1) If there is a deviation angle in the steering zero adjustment information before traveling, the steering angle on the front side in the traveling direction cannot be accurately measured.
As shown in FIG. 6, the bogie skews by the shift angle Δα.

(2) Next, the amount of displacement of the control point on the front side in the traveling direction is measured by the magnetic sensor 2a, and the error Δyf between the estimated bogie position and the actual bogie position at this time is assumed to be caused by the attitude angle error of the bogie. Then, the next attitude angle correction amount θ is calculated and corrected by the calculator according to the following equation. θ = atan (Δyf / x) x: running distance

(3) When the attitude angle is corrected as described above,
As shown in FIG. 6, the position shift amount of the control point on the front side in the running direction disappears, and only the control point on the rear side in the running direction has the position shift amount. This is because the attitude angle was corrected by assuming that the position error Δyf generated at the control point on the front side in the traveling direction was caused by an error in the attitude angle. (Is the position error Δyf of the control point on the front side in the traveling direction caused by the error in the attitude angle? , Because it cannot be determined whether it is due to the deviation angle of the steering zero adjustment).

(4) Next, when the magnetic sensor 2b detects the amount of displacement of the control point on the rear side in the traveling direction, the error Δyr between the estimated bogie position and the actual bogie position at this time is the steering-side steering zero adjustment. It is due to the deviation angle of
The shift angle Δα is obtained by the calculator based on the following equation. Δα = asin (Δyr / L) L: distance between the control point on the front side in the running direction and the control point on the back side in the running direction (for example, the distance between the center of the magnetic sensor before and after the running) The control point is controlled so as to follow the running path. It is a point to do.

(5) The front steering angle in the traveling direction is corrected using the deviation angle Δα.

[0017]

According to the present invention, during automatic driving by the gyro guidance system,
Find the deviation angle of the steering null information on the rear side in the traveling direction,
Thus, when the steering angle on the front side in the traveling direction is corrected, an accurate steering angle can be obtained, so that the accuracy of the bogie position calculation is improved and stable traveling can be realized.

[Brief description of the drawings]

FIG. 1 is an example of a bogie position calculation model.

FIG. 2 is a block diagram showing a system configuration of a gyro-guided automatic guided vehicle.

FIG. 3 is a back view of the truck showing an arrangement of the magnetic sensors and the like.

FIG. 4 is a front view showing an arrangement of a magnetic sensor and a magnetic marker on a truck and a floor surface.

FIG. 5 is an image diagram for explaining a method of detecting a magnetic marker by a magnetic sensor installed on a cart.

FIG. 6 is a conceptual diagram illustrating a method of correcting a deviation angle of a steering zero adjustment.

[Explanation of symbols]

 1 Wheel 2a, 2b Magnetic sensor 3 Gyro 4a, 4b Magnetic marker 5 Bogie main body

Claims (1)

[Claims] 1. A two-wheel independent vehicle for calculating a bogie position by an arithmetic unit using a measured value such as a traveling distance measured by a traveling distance sensor and a steering angle measured by a steering angle sensor during automatic traveling by a gyro. In a steering gyro-guided automatic guided vehicle, the displacement of the front control point in the traveling direction is measured, and after correcting the bogie position and the attitude angle, the displacement of the rear control point in the traveling direction is measured. An error correction method for steering zero-tone information in a gyro-guided automatic guided vehicle, wherein a deviation angle of the steering zero-tone information on the front side in the traveling direction is obtained from the positional deviation amount.