JPH0381806A - Method for running unmanned carrier vehicle - Google Patents

Abstract

PURPOSE:To surely transfer an anmanned carrier vehicle from autonomous traveling to guide traveling by measuring vehicle position form guide elements based upon guide element detecting information, correcting the vehicle position measuring value of autonomous traveling and switching the traveling mode. CONSTITUTION:When the unmanned carrier vehicle traveling while being guided along the guide elements 20, 21 arrives at a rotation point, a branch point, an intersecting point, etc., a signal plate sensor 9 sends information obtained from a signal plate 23 on the route to a traveling mode switching device 8 and a position measuring instrument 7 starts the position measurement of the vehicle 1 based upon a switching command to the autonomous traveling outputted from the device 8. When the detection of autonomous traveling based upon the position measurement value is enabled after disabling the detection of the guide elements, the autonomous traveling based upon the corrected position measurement value is executed to guide the vehicle 1 to the guide element on the target route side. When the sensor 9 detects a a signal plate 24 meaning the end point of the autonomous traveling, the device 8 outputs a switching command for switching the autonomous traveling to the guide traveling.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a traveling method for an automatic guided vehicle.

[Conventional technology]

The way the automated guided vehicle travels is by attaching guidance tape to the floor as a predetermined main route, which guides the vehicle, and at branch points, turning points, intersections, etc. There are some that use a combination of guided driving and autonomous driving, with autonomous driving along the route.

[Problem to be solved by the invention]

In this way, in a driving method that combines autonomous driving and guided driving, when moving from autonomous driving to guided driving,
If the body of the automated guided vehicle is not precisely aligned with the guidance element at the end point of autonomous travel, the sensor installed on the vehicle body will not be able to detect the guidance element on the floor, and the vehicle will not be able to shift to guided travel. It becomes impossible. To prevent this, conventional methods have required either expanding the effective range of the sensor so that the induction element can be detected even if the vehicle body is slightly deviated from the induction element, or performing highly accurate autonomous driving so that the vehicle body follows the induction element. be.

Increasing the effective range of the sensor in this way also increases the power consumption by the sensor, which is also a disadvantage for battery-powered automatic guided vehicles. Additionally, high-precision autonomous driving requires expensive equipment.

It is an object of the present invention to set the effective range of the sensor to the minimum allowable range necessary for guided travel on a straight road, and to make it possible to reliably transition from autonomous travel to guided travel without deviating from the travel route.

[Means to solve the problem]

The present invention has been made to achieve the above-mentioned object, and includes an automatic guided vehicle that travels autonomously on a curved road such as a branching point, an intersection point, or a turning point of a traveling route through guided travel using a guiding element. When transitioning from autonomous driving to guided driving, the vehicle passes through a guiding path during autonomous driving, and the vehicle body position relative to the guiding element is measured from the azimuth measurement value of the vehicle body at the time of passing and the guiding element detection information of the sensor. The system corrects the measured value of the vehicle body position during autonomous driving, and when the azimuth and deviation of the vehicle body relative to the guidance path are within a predetermined tolerance range, it switches to guidance driving using the guidance element and reliably guides the vehicle to the guidance element of the guidance path. .

〔Example〕

The present invention will be explained below based on the illustrated embodiments.

FIG. 1 shows the main parts of the automatic guided vehicle according to the present invention. The vehicle body 1 includes a steering wheel 2 equipped with a steering motor M1, and left and right drive wheels 4.5 driven by a travel motor M2 via a differential gear 3. A control device 6 that controls the wheel 2, a position measurement bag M7
, and is electrically connected to input a signal from a signal plate sensor 9 to the driving mode switching device 8 and to input a signal from an inductive element sensor 10 provided on the vehicle body 1 to the position measuring device 7. Ru.

Further, a left rotation amount sensor 11 is installed on the left drive wheel 4, and a left rotation amount sensor 11 is installed on the left drive wheel 4.
are provided with a clockwise rotation amount sensor 12, respectively, and both sensors 11
, 12 so as to input signals to the position measuring device 7.

Further, on the floor F, there is a guiding element 20.2 for guiding the automatic guided vehicle along a predetermined guiding route (traveling path).
The second-class induction elements 20 and 21 are arranged so as to cross each other, and a signal plate 23 and 24 is used to catch a signal for the conveyance vehicle to move from one induction element 20 to the other induction element 21. are provided at optimal positions of each element 20,21. Inductive elements 20, 21, signal plates 23, 24, etc.
In this embodiment, a tape-shaped material is shown, but it is needless to say that the material is not limited to this.

Therefore, the vehicle body 1 of the automatic guided vehicle detects the guiding elements 20 and 21 of the vehicle traveling along the guiding route 20 or 21 by the guiding element sensor 10, and travels along the guiding element. When moving from one guiding element 20 to the other guiding element 21 that intersects with it, the vehicle autonomously travels from the signal board 23 to 24, and this guided traveling and autonomous traveling are provided at 20 and 21 on the route. The signal board sensor 9 detects the signal boards 23 and 24 and switches the driving mode between guidance using the induction element and autonomous driving. give instructions.

Further, the output of the running motor M2 is divided into two by the differential gear 3, and the left and right drive wheels 4.5 are rotated to make the vehicle body 1 run, and the amount of rotation is detected by rotation amount sensors 11 and 12, respectively. , and sends the signal to the position measuring device 7.

The steering motor M1 rotates the steering wheels based on commands from the control device 6, determines the traveling direction of the vehicle body 1, and guides the vehicle along a predetermined route along the guidance element, or performs a predetermined direction during autonomous driving. The vehicle is controlled so that it travels along a predetermined route.

When the inductive element sensor IO detects the inductive element 20 or 21, it sends and outputs the detection information to the position measuring device 7.

When the signal board sensor 9 detects the signal board 23 or 24 on the route, it sends and outputs the detection information to the driving mode switching device. And this driving mode switching device! ! 8 and the position measuring device 7 are connected to each other, and their operation is changed by a changeover switch SW in response to a command from a driving mode switching device.

Therefore, when the vehicle body 1 travels on a guided route using the guiding element 20 or 21, the guiding element sensor 10 measures the deviation between the vehicle body and the guiding element based on the information detected by the guiding element 20 or 21, and determines the deviation. The steering angle is calculated so that the vehicle moves in the direction in which the distance becomes zero, the steering information is sent to the control device, and the steered wheels are steered so that the vehicle travels along the route.

The control device then controls the amount of rotation of the steering motor so that the steering information output from the position measuring device matches the actual steering angle, and in this way the vehicle body moves along the induction element or along the target path as described below. The vehicle is driven by

In the case of autonomous driving, when the signal board sensor 9 detects a signal board while guiding the vehicle along a route, the driving mode switching device switches the vehicle from guided driving to autonomous driving. This is a rotation amount sensor 11 provided on the left and right drive wheels 4, 5,
The distance traveled by the vehicle body is calculated from the average amount of rotation of both left and right drive wheels 4.5 sent from 12, and the azimuth angle of the vehicle body is calculated from the difference in amount of rotation between the two wheels, and the deviation from the target path stored in advance as position information is calculated. The steering information is output so that the value becomes zero. In this way, when the guidance element sensor detects the guidance element during autonomous running, the vehicle body position measurement value with respect to the guidance element is corrected based on this detection information and the vehicle body azimuth obtained by position measurement during autonomous travel.

FIG. 4(A) shows the autonomous running mode.

From the signal board 23 to point a, where the guidance element of the target route is detected, the position is measured using the vehicle body center position on the signal board 23 as a reference point, and at point a, the position measurement value is corrected. Since the guidance element cannot be detected again from point a to point b, the vehicle body is guided by autonomous running using point a, whose position has been corrected, as a reference point. At point b, the inductive element is detected again and the position is corrected.

From point b to point 0, the vehicle moves autonomously by measuring its position using point b as a reference point. Since the induction element can be detected at all times from the 0 point to the signal board 24, the position is constantly corrected and the vehicle autonomously travels according to the results.

When the signal board 24 is detected, the vehicle switches to guided travel.

The signal board 24 is used to confirm whether the azimuth and deviation of the vehicle body with respect to the guideway are within a predetermined tolerance range.

FIG. 4(B) shows the autonomous running in the conventional system for comparison with the system of the present invention. In the conventional system, the vehicle autonomously travels between the signal board 23 and the signal board 24. During this period, the vehicle autonomously travels by measuring the position up to the signal board 24 from the center position of the vehicle body at the time of detection of the signal board 23, and does not correct the position.

Next, a method of traveling an automatic guided vehicle according to the present invention will be explained according to the flowchart shown in FIG.

When an automated guided vehicle that is guided along the guidance element reaches a route change point such as a turning point, branch point, or intersection, the signal board sensor detects the signal board on the travel route and uses that information to change the travel mode. Output to switching device. The driving mode switching device uses this output to output a command to switch the driving mode to autonomous driving to the position measuring device. The position measuring device extracts data on the center of the vehicle body at the time of detecting the signal board and the distance and azimuth of the target route from a pre-stored data table, sets the data as position information on the target route, and starts measuring the position of the vehicle body. If the guidance element on the target route side cannot be detected, the deviation from the target route is calculated based on the position information of the target route and the vehicle body position and azimuth determined by position measurement, and the vehicle autonomously travels on the target route. When the guidance element on the target route is detected, the position measuring device determines the vehicle body position with respect to the target route from the vehicle azimuth angle θ determined by position measurement, the position Ds where the guidance element sensor detects the guidance element, and the distance Ws between the center of the vehicle body and the sensor center. is calculated using the following formula, and the position measurement value is corrected.

x=L-Ds cos θ-Ws sin θ where L: target route coordinates Then, based on the corrected accurate position measurement value, the vehicle autonomously travels onto the guidance element on the target route side.

Thereafter, when the guidance element cannot be detected, the vehicle runs autonomously using the position measurement value, and when it can be detected, autonomous travel occurs using the corrected position measurement value, and guides the vehicle body onto the guidance element on the target route side. When the signal board sensor detects the signal board indicating the end point of autonomous driving, the driving mode switching device outputs a command to switch the driving mode to guided driving, and the position measuring device also switches its operation to guided driving, and instead moves along the guiding element. drive.

FIG. 7 is a flowchart showing a conventional traveling method for comparison with the traveling method according to the present invention. By setting the autonomous driving route so that the vehicle enters the target route obliquely at a shallow angle as shown in FIG. 3(A), the target route side guidance element can be reliably detected.

In addition, in the conventional system, the route for autonomous driving is shown in Figure 3 (B).
As shown in Figure 2, the target route detection point was set at the point where the vehicle body was at the same angle as the target route, so if an error occurred in the autonomous travel route, it was impossible to detect the target route. Furthermore, in order to prevent this, the effective range of the induction sensor had to be widened by taking into account the route error.

〔Effect of the invention〕

The traveling method of the present invention has the following effects.

■ Even during autonomous driving, when a guidance element on the target route side is detected, errors in autonomous driving information are corrected based on that information, so the tolerance range for errors in autonomous driving route information and position measurement information is widened. This eliminates the need for expensive equipment such as gyros.

- After detecting the guiding element and correcting its position, the vehicle is guided to the guiding element by autonomous running, so the effective range of the guiding element sensor can be reduced.

(Extreme theory 1, however, since straight-line driving is guidance, the sensor can be reduced to the minimum range required for straight-line driving.) ■ By setting the autonomous driving route so that the vehicle approaches the target route diagonally, Even if the effective range of the inductive element sensor is small, the inductive element can be reliably detected and position correction can be performed.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the vehicle body of an automated guided vehicle, Fig. 2 is an explanatory diagram of vehicle body position correction, and Fig. 3 is an explanatory diagram of setting an autonomous driving route.
(A) shows the present invention, (B) shows a conventional example, and Fig. 4 is an explanatory diagram during autonomous driving. 6 is a block diagram of a control device, and FIG. 7 is a flowchart of a conventional traveling method. 1 is the vehicle body, 2 is the steering & 4.5 is the drive wheel, 6 is the control device, 7 is the position measurement device, 8 is the driving mode switching device, 9 is the signal plate sensor, 10 is the induction element sensor, 11.12 is the rotation Quantity sensor, 20° 21 is an induction element, 23.24 is a signal board, Ml is a steering motor, and M2 is a travel motor. 3rd (B)

Claims (1)

[Claims] (1) A driving method for an automatic guided vehicle in which a driving route is indicated by a guidance element and the automatic guided vehicle is guided along this traveling route, and autonomous driving is performed at branch points, intersections, turning points, etc. of the route. In combination, when an automated guided vehicle moves from autonomous driving to guided driving, it passes through a guiding path during autonomous driving, and calculates the vehicle body position relative to the guiding element based on the measured value of the vehicle's azimuth angle at the time of passing and the information detected by the guiding element of the sensor. The measured value of the vehicle body position during autonomous driving is corrected based on the results, and when the azimuth and deviation of the vehicle body with respect to the guidance travel path are within a predetermined tolerance range, the system switches to guided travel using the guidance element. A method of driving an automated guided vehicle characterized by: