JPS63318608A - Unmanned carrying vehicle - Google Patents

Abstract

PURPOSE:To attain guidance control with high accuracy at low cost by the self-contained navigation, by confirming the attitude angle information by utilizing a difference in speed of revolution of the right and left wheels when an attitude angle changes, and a marker which is laid on a fixed position, and detecting the attitude angle without using a gyroscope. CONSTITUTION:By starting a motor controller 16, and rotating the running use motors 17a, 17b, the right and left running driving wheels rotates and a carrying car starts to run. The rotation of the driving wheel is detected by encoders 4a, 4b, and a distance pulse being proportional to the speed of revolution of the driving wheel is generated. Subsequently, this pulse is inputted to the corresponding counter circuits 6a, 6b, respectively, and the distance pulse is counted by setting a prescribed time as a counting period. Whenever the prescribed time elapses, a count value is outputted, and after it cleared, counting is executed again. The count value is fed to an adding circuit 7 and a subtracting circuit 8 and calculated, fed to a present position arithmetic unit 9, and by calculating an attitude angle and a moving distance, the present position is obtained. When the vehicle has passed through a position detecting marker 12, the device 9 corrects the attitude angle and the position by the output of an absolute position detecting device 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a self-contained navigation type automatic guided vehicle used primarily for automatic transportation within a factory.

(Conventional technology) In recent years, FA () one-factory automation in production factories has been increasing.
(silane), and automated guided vehicles are being used to efficiently and automatically transport various objects within factories to their desired locations. The guidance method of these automatic guided vehicles is an electromagnetic induction method in which a high-frequency current is passed through an N magnetic induction wire buried in the running floor, and the induced magnetic field generated by this is detected by a coil installed on the vehicle. Optical guidance systems are common, in which reflective tape pasted on the driving route is detected by an on-vehicle optical sensor to provide guidance. These are all methods in which an automated guided vehicle travels along a route formed by electric wires or data, but apart from this, there is also a method that uses sensors installed on the guided vehicle itself to know the location of the vehicle and follow a given travel route. Autonomous guided vehicles with autonomous navigation that perform guidance and control based on information have recently become popular. This method has the advantage that it does not require installation of electromagnetic induction wires or reflective tape, and can also be applied to relatively complicated routes.

There are various means for a self-navigating automatic guided vehicle to know the position of its own vehicle, and for example, there is one that uses a rate gyro. The rate gyro outputs an analog value corresponding to its own rotational angular velocity, and in this case is used to determine the running azimuth of the automatic guided vehicle. In this method, based on a known fixed point, the current position of the own army is calculated based on the travel distance obtained from the travel azimuth obtained from the rate gyro and the rotation speed of the travel wheels, and guidance control is performed according to the given travel route information. conduct.

(Problem to be solved by the invention) In this way, self-navigating automatic guided vehicles use a rate gyro to determine the traveling azimuth of the own vehicle. An integrator is required to integrate the output angular velocity of the conveyance vehicle to determine a change in traveling azimuth, and the guidance control system becomes complicated.

Furthermore, the detection error of the rate gyro greatly affects the guidance error of the guided vehicle, and if a highly accurate rate gyro is used, the price of the guidance control device will increase.

Therefore, it is an object of this invention to detect the traveling azimuth of a guided vehicle by using an azimuth angle detection device represented by a rate gyro.
An object of the present invention is to provide a self-contained navigation type automatic guided vehicle that can perform detection with high accuracy without any noise and can reduce the cost of a guidance control device.

[Configuration of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention is configured as follows. In other words, there is a pair of drive wheels in the center of the vehicle body that are driven independently on the left and right sides, and a rotation speed detector for the left wheel generates pulses corresponding to the rotation speeds of these left and right drive wheels, respectively. Calculation means for obtaining information on the sum and difference of the outputs of both rotation speed detectors obtained every predetermined uplink period in an automated guided vehicle that controls the rotation speed difference between left and right drive wheels to perform direction control based on the information obtained. and a pair of left and right sensors provided on the automatic guided vehicle to simultaneously detect the markers when at least the traveling direction of the automatic guided vehicle coincides with a marker placed at a predetermined position on the road surface of the traveling route; a current position calculation means that calculates the current coordinate position and attitude angle based on both output information of the calculation means, and corrects these calculated values based on the outputs of the pair of sensors; positional deviation calculating means for obtaining positional deviation information by comparing the coordinate position and attitude angle information obtained by the current position calculating means based on data of the travel route determined by the current position calculating means;
A motor control means for controlling the rotational speed of the left and right drive wheel drive motors in a direction to suppress the deviation in accordance with the positional deviation information.

[Effect]

In such a configuration, the vehicle body is moved to a certain marker position and traveling is started using this as a reference point. When you start driving, the rotation speed detectors for the left and right wheels generate a signal corresponding to the rotation speed. This q pulse is given to calculation means, where the sum and difference values of both pulses are obtained at intervals of a predetermined chimpling period. Then, based on the sum and difference values, the current position calculation means calculates the coordinates and attitude angle of the current position of the vehicle body.

The calculated values of the coordinates and attitude angle are given to the position deviation calculation means, and this calculation means compares the coordinates and attitude angle information obtained by the current position calculation means with reference to data regarding the travel route set in advance. to obtain position deviation information. This positional deviation information is given to the electric motor control means, and the electric motor control means controls the rotational speed of the electric motors for driving the left and right drive wheels in accordance with the positional deviation information so as to suppress the deviation.

Furthermore, when the vehicle passes a marker position, a pair of left and right sensors detect this. When the posture of these pair of sensors is tilted with respect to the direction, a difference occurs in the detection time. Therefore, the actual attitude angle is determined by the timing of this marker detection output, and since the marker is at a fixed position, the absolute position coordinates can also be known. Therefore, the coordinates of the current position and the attitude angle are corrected using the marker detection output to correct the error.

Since the attitude angle of the vehicle body is determined by utilizing the difference in rotation speed between the left and right wheels when the button attitude angle changes, unmanned driving using autonomous navigation is possible without using an azimuth angle detector such as a gyro. Moreover, since the absolute coordinate position and attitude angle information can be confirmed using markers installed at fixed positions, the system is inexpensive and can perform independent navigation with high precision guidance. We can provide a type of automated guided vehicle.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In general, in self-navigating automatic guided vehicles using a two-axis independent power system, the traveling azimuth of the guided vehicle is determined by a rate gyro, and the traveling distance is determined by the average rotation speed of the left and right drive wheels.
As a result, the position coordinates of the transport vehicle are calculated sequentially and guidance control is performed according to the given travel route information. However, the present invention allows the traveling azimuth of the transport vehicle to be adjusted based on the rotational speed difference between the left and right drive wheels. Guidance control is performed by determining the travel distance based on the average rotation speed of the drive wheels.

That is, in an automatic guided vehicle with two-axle independent drive, in order to detect the rotation speed of the left and right drive wheels, the travel drive unit is generally equipped with an encoder that generates a distance pulse proportional to the rotation speed of each drive wheel. ing. If the running direction of the automated guided vehicle changes, it will be reflected in the rotation speed of the left and right drive wheels, so information on the distance/arm length and running azimuth of the left and right drive wheels output by the encoder is obtained and used for guidance control. Make use of it.

Examples of the present invention will be described in detail.

FIG. 2 is a bottom plan view showing the configuration of a two-axis independent drive automatic guided vehicle. In the figure, 1 indicates the vehicle body.

Further, 1 m and Ib are driving wheels], which are arranged on the left and right sides of the lower center of the vehicle body 1, respectively. 31.degree. 3b is a travel drive unit for wheel travel braking control that is provided independently for each travel drive wheel 1m and 2b, and each has an electric motor, a speed reducer, and a brake. 4m and 4b are provided on the running drive wheels 1m and 2b, respectively, and are encoders that output distance pulses proportional to the rotational speed of the running drive wheels 2m and 2m; 5a and 5d are adjustable driven wheels (
These flexible driven wheels 5a, 5c, which are casters), are provided on the front, rear, left and right sides of the vehicle body 1.

This automatic guided vehicle operates under the control of a guidance control device (not shown), and the left and right travel drive units (J m e j b) operate, and the left and right travel drive wheels j! This is done by controlling the rotational speed difference between a and 2b.

FIG. 1 is a block diagram showing an embodiment of a guidance control device for a self-navigating automatic guided vehicle according to the present invention.

In the figure, 4m and 4b are the above-mentioned encoders.

1m and 6b are respectively corresponding encoders 4a.

A counter circuit that counts the output pulses of 4b within a certain period of time and outputs it as distance data traveled by the driving wheels 1m and 2b within this time, 1 is a count value output by both counter circuits 6m and 6b. 8 is a subtraction circuit that calculates the difference between the count values of both counter circuits 6a and fib, and # is a subtraction circuit that calculates the difference between the count values of both the counter circuits 6a and fib. 1z is a detected marker s installed on the travel route of the transport vehicle and serves as an absolute position detection target; 13a and Isb are the detected markers 12;
The above-mentioned absolute position detection device 11 outputs a detection output in order to determine the attitude angle of the transport vehicle and the absolute position on the traveling route based on the detection output of the detected marker 12 of sensor+13m and 13b. It is something to do.

Reference numeral 14 denotes a position deviation calculating device which calculates a deviation from a predetermined traveling route based on the current position of the guided vehicle determined by the current position calculating device 9Vc and preset traveling route data 15.

Further, 16 is a traveling IItMJ machine control device, which corrects the traveling direction of the guided vehicle based on the deviation ξ, and adjusts the traveling direction of the guided vehicle so that the position coordinates of the guided vehicle coincide with the coordinates on the determined traveling route. Drive unit) Ja.

3bt-Electric driving pi9.17 m,
17b is controlled by the rotational speed difference.

Next, the operation of this device having the above configuration will be explained.

First, position detection markers 12 are installed at a plurality of predetermined points on the driving route, and driving route data 15 including information on the installation of these markers is set in advance on the vehicle. The position detection marker I2 has a triangular shape in order to also detect attitude angle information of the vehicle body 1, and the on-vehicle sensors 13m and 13b are arranged so that the center of the vehicle body 1 passes through the center line of this triangular position detection marker 12. The centimeters 13a and 13b can generate detection outputs at the same time unless the vehicle body 1 is deviated from the position detection marker 12. .

The electric motor control device 16 is activated, and the driving electric motor 17m is activated.
When the wheel 17b is rotated, the travel drive wheels 2a and Jb rotate, and the transport vehicle starts traveling.

At this time, the rotation of the left and right running drive wheels 2a, 2b is detected by the two encoders 4bK, and the encoders 4m, 4b generate distance pulses proportional to the rotational speed of the running drive wheels 1m, 2b. are the corresponding counter circuits 6a, respectively.
, 6b, each of the counter circuits 6m, 6b counts the distance to the elbow with a predetermined time as a counting period, and outputs the count value every time the predetermined time elapses;
Clear it and then run the count again. These count values are given to an adder circuit r and a subtracter circuit 8, and each circuit 7.1 performs addition and subtraction and provides the result to a current position arithmetic unit 9Vc.

The current position calculation device 9 calculates the attitude angle and the movement distance based on these calculated values, and determines the current position.

Furthermore, when the vehicle passes through the position of the position detection marker 12, the current position calculation device 9 corrects the attitude angle and position based on the output of the absolute position detection device 11.

Here, the current position can be determined as follows.

A certain fixed point on the travel route is set as the origin, and an xy orthogonal coordinate system is established on the route plane. Further, the running azimuth angle (attitude angle), which is the angle between the traveling direction of the transport vehicle 10 and the X-axis, has the X-axis as the starting angle and the counterclockwise direction as positive. In Figure 3, now,
The traveling O-transported vehicle 10 at time t has the coordinates (”n*3
'n) K position, and the running azimuth (attitude angle) is θ. Suppose that

Now, the coordinates (Xn+r*Yn+r) and attitude angle θ of the transport vehicle at time tn+t after a time of Δ. + means 2 m of the left and right running drive wheels that traveled this Δ within the time.

2I) Distance data 1. , lb. That is, if we assume that the guided vehicle 10 makes a turn with radius R within the time Δ and the attitude angle change during this time is Δθ, then (R-T)・Δθ=l, . . .・・・
・・・・・・(1)(R+T)・Δθ=lb
・・River・Song・(2) (However, W
: known for the tread of the drive wheel). Therefore, the coordinate CXfl at time in+1
+Is)'n+*, attitude angle θ. +, is θn+t
=θ. +Δθ...Song...(7
), which can be obtained from the output data 1m-6b of the counter circuits 6m and 6b shown in FIG.

The addition circuit 7 and the subtraction circuit 8 are circuits for calculating la+lb, and the results are inputted to the current position calculation device 9'\C. The current position calculation device 9 is given nine input data C
1+1) and CI, -J,) a b Yoshi (8), (4), (5), (6)
, Xrl+t a obtained by calculating equation (7)
1n+s s 'net to new Xn mYn, θ.

By repeating the calculation as follows, the current position of the guided vehicle while it is traveling is determined one by one. The current position calculation device @9 calculates the current position by sequentially adding the relative position changes of the guided vehicle from the calculation start point, so the initial conditions at the start of operation of the automatic guided vehicle, that is, the absolute position of the guided vehicle at the start of operation, are Position coordinates (XosFo) and attitude angle θ. must be entered. This input means is the absolute position detection device 11. There are various types of this device, an example of which is shown in Japanese Patent Publication No. 60-175118. It is generally constructed from an arithmetic circuit that calculates the absolute position of the . Therefore, this system is also adopted in this system.

This method will be explained in more detail. As shown in FIG. 4, an isosceles triangular detection marker 12 is installed at a fixed point on the traveling route (RT) whose coordinate position is known, and this is placed on the transport vehicle 1.
By detecting with the pair of left and right sensors 13m and 11b provided on the vehicle 10, the absolute position coordinates and attitude angle of the conveyance vehicle 10 when it passes the detected marker 12 can be determined. That is, the distance 11 traveled by the guided vehicle 10 from when one of the sensors 13g detects the detected marker 12t to when the other isb detects the marker 12t, and the inter-sensor distance lf.
And K and attitude angle, and this and sensor 13m.

13bQ:) The absolute position coordinates can be obtained from the detection distance of the detected marker 12 @l5-1+.

On the other hand, the absolute position detection device 1 is also used to correct the current position determined by the current position calculation device 9 while the vehicle is running. As the current position calculation device 9 repeats the calculation, an accumulated error occurs due to deflection of the running wheels, unevenness of the running floor, etc., and an error occurs between the current position of the guided vehicle calculated by the calculation and the actual position. . For this reason, for example, the detected marker 1 is placed at several points on the traveling route 18 as shown in FIG.
2 is installed, and when passing the marker, the absolute position detection device 11 corrects the current position of the guided vehicle calculated by calculation, thereby preventing the accumulation of errors.

In this manner, the current position is determined, and information on the determined current position is provided to the position deviation calculation device 14.

The position deviation calculation device 14 uses this and the travel route data 15 to determine the deviation e from the determined travel route.

Then, this deviation e is given to the driving electric motor control device 16. In response to this, the running tS machine $-II control device i! 16
In order to correct the running direction corresponding to the deviation eVc, the two running electric motors 11ts and Irb are controlled by the rotational speed difference. As a result, the direction of the transport vehicle is corrected so that the position coordinates of the transport vehicle match the determined travel route, and the transport vehicle travels.

As described above, the self-navigating automatic guided vehicle according to the present invention does not require a device for detecting the attitude angle of the guided vehicle such as a rate gyro, and its guidance control device does not require a device for detecting the attitude angle of the guided vehicle, such as a rate gyro. The current position of the transport vehicle is calculated based on the distance pulse detected by the encoder attached to the vehicle, and therefore a simple and inexpensive guidance control device can be provided. Furthermore, the encoder is used to detect the rotational speed of the traveling drive wheels using the rotational motor mK of the traveling electric motor, and is also installed in automatic guided vehicles using other guidance methods (electromagnetic type, optical type). Therefore, the guidance control device of the present invention can be used in combination with automatic guided vehicles of other guidance methods without adding a new detection device.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with appropriate modifications within the scope of the gist thereof.For example, as shown in FIG. The construction is such that freely rotatable idlers 20m and 20b are arranged inside the idlers 1m and 2b so that these and the grounding points are aligned in a straight line, and encoders 4m and 4b are provided for the idlers: lO* and JObVc, respectively. It is possible to obtain a distance pulse corresponding to the traveling of the transport vehicle without being affected by the slippage between the wheels 2m, 2b and the floor surface 22, and it becomes possible to perform guidance control with high precision.

〔Effect of the invention〕

As detailed above, according to the present invention, it is possible to provide an automatic guided vehicle that detects the attitude angle without using a gyro, enables highly accurate guidance control by self-contained navigation, and can perform guidance control at low cost. be able to.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a configuration example of the guidance control device used in the present invention, Fig. 2 is a bottom plan view of an automatic guided vehicle with two-axis independent drive system, and Fig. 3 is a current position calculation method used in the device of the present invention. The fourth factor is a diagram showing an example of attitude angle detection by detecting a detected marker, FIG. 5 is a diagram showing an example of a travel route, and FIG. It is a front view showing an example. 1...Vehicle body, 1m, 2b...Traveling drive wheel, JJI
. 3b... Traveling wind m unit, 4a, 4b... Encoder, 5!1. ~5d...Swivel driven wheel, 6m, σ
b...Counter circuit, 1...Addition circuit, 8...Subtraction circuit, 9...Current position calculation device, 10...Transportation vehicle, 1...Absolute position detection device, 12...・Detected marker, IJIm. 13b...Sensor, 14...Position deviation calculation device, 1
5... Traveling route data, 16... Electric motor control device, 17m, 17b... Traveling electric motor, 18. RT...
・Driving route. Rented Patent Attorney Rin Ushiki Hiko 10th 12th 20th

Claims (2)

[Claims] (1) There is a pair of drive wheels in the center of the vehicle body that are driven independently on the left and right, and pulses corresponding to the rotation speed of these left and right drive wheels are generated by rotation speed detectors for the left wheel and right wheel, respectively. In an automatic guided vehicle that obtains distance information from this and performs direction control by controlling the rotation speed difference between left and right drive wheels, information on the sum and difference of the outputs of both rotation speed detectors obtained every predetermined uplink period. a marker placed at a predetermined position on the road surface of the travel route; and a right pair of markers provided on the automatic guided vehicle so as to simultaneously detect the markers at least when the traveling direction of the automatic guided vehicle coincides with the travel route. Current position calculation means that calculates the current coordinate position and attitude angle based on the output information of both the sensor and the calculation means, and corrects these calculated values based on the outputs of the pair of sensors. , positional deviation calculating means for obtaining positional deviation information by comparing the coordinate position and attitude angle information determined by the current position calculating means based on preset travel route data;
An automatic guided vehicle characterized by comprising: electric motor control means for controlling the rotational speed of the left and right drive wheel driving electric motors in a direction to suppress the deviation in accordance with the positional deviation information. (2) The automatic guided vehicle according to claim 1, characterized in that a pair of left and right idlers is provided on a line connecting the grounding points of the left and right drive wheels, and a rotation speed detector is provided on each of the idler wheel shafts.