JPH11245839A - Multi-axis automated guided vehicle - Google Patents

Abstract

(57) [Problem] To provide a multi-axis automatic guided vehicle that can carry a heavy object at high speed and stably and can maintain an optimal traveling state according to a change in traveling conditions. SOLUTION: In a multi-axis automatic guided vehicle, a guide sensor for normal traveling control for controlling traveling and steering of a plurality of wheel groups on a vehicle body, and a traversing device for performing traversing and steering control in a direction perpendicular to the traveling direction. Providing a guide sensor and a marker detector for detecting a marker arranged on the traveling line, and determining the traveling speed and the steering angle of each wheel of the traveling wheel device, always optimally responding to the ever-changing traveling conditions. A control device for controlling the speed and the angle is provided, and a traveling drive mechanism and a steering mechanism for independently driving each wheel of the traveling wheel device according to a command from the control device are connected to the traveling wheel device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic guided vehicle, and more particularly to a multi-axis automatic guided vehicle suitable for transporting heavy objects such as a steel sheet coil, a sheet and a papermaking coil.

[0002]

2. Description of the Related Art A multi-axis automatic guided vehicle suitable for carrying heavy objects of this type employs a double-wheeled traveling wheel device in order to reduce the load applied to the wheels to an allowable value or less. For example, Japanese Utility Model Publication No. 1-15644 discloses an unmanned vehicle equipped with a guide sensor for detecting a derivative laid on a traveling path and a control device for controlling steering and driving of traveling wheels based on a detection signal of the guide sensor. A carrier is disclosed. This automatic guided vehicle is provided with two front and rear single-wheel drive wheels arranged so as to be able to turn on the center line of the vehicle body and four casters arranged at four corners of the vehicle body. A guide sensor and a reverse guide sensor are provided.The forward guide sensor and the reverse guide sensor for the front wheel are used for the front wheel derivative laid on the traveling path, and the rear guide sensor and the reverse guide sensor for the rear wheel are used for the front wheel. The control device detects the derivative of the rear wheel, which has a different frequency, and based on the signals of the front wheel guide sensor and the rear wheel guide sensor, the control device converts the front wheel to the front wheel derivative and the rear wheel to the rear wheel derivative. The vehicle travels by steering along each of them.

[0003]

By the way, with the increase of the carrying weight, only the two wheels of the general four-wheel structure cannot satisfy the load bearing capacity of the existing traveling road even if the wheel tire diameter is increased. It is necessary to reduce the load per wheel as a multi-axis having six or more wheels. As for the normal four-wheel control, various measures have been proposed as shown in the above-mentioned Japanese Utility Model Publication No. 1-15564, but it is necessary to simply apply them to a multi-axis automatic guided vehicle having six or more axes. However, there are many technical problems, and it is extremely difficult to transport a high-speed and large-weight with high accuracy.

When a heavy object is to be transported, the load is usually mounted at a position closer to the vehicle center of gravity than the vehicle body strength. However, in the above-mentioned prior art, the load is concentrated on the central driving wheel, and a large number of wheels are provided. Even if it does, it is impossible to disperse the load. As a result, there is a possibility that problems such as acceleration of wheel wear, deformation of the road surface due to concentrated load, and damage to the dielectric may occur.
Furthermore, since the wheel and the guide sensor move together,
Applicable when the number of wheels is small. However, when considering the control of six or more multi-axial wheels, it is necessary to arrange the wheel positions uniformly in the width direction and the longitudinal direction of the vehicle body in order to equalize the load. For this reason, it is difficult to mount and control a guide sensor with the same axle structure as the steering axle as in the above-mentioned conventional technology, and it is necessary to increase the number of guide sensors or to use a plurality of derivatives corresponding to each axle on the road surface. Must be laid, and the structure becomes complicated.

Accordingly, the present invention provides an automatic guided vehicle having three or more wheels and six or more wheels, capable of carrying heavy objects stably, and having a large body length and high speed. In order to run, two fixed guide sensors in front and back detect one derivative and run, improving the followability of delicate control for each running wheel device, ensuring straightness during running, stopping at a fixed point It is an object of the present invention to provide an automatic guided vehicle with improved high-speed running stability and excellent high-speed running stability.

[0006]

Means for Solving the Problems In order to achieve the above object, the present inventors have set up an experimental facility for multi-axis unmanned transfer of heavy objects, grasped its traveling characteristics and control characteristics, and conducted extensive experiments and experiments. As a result of the study, the present invention has been completed.

That is, the gist of the present invention is as follows. (1) A traveling wheel device having three or more axes and six or more wheels in the front-rear direction, at least four of which are driving wheels, and a traveling wheel device capable of independently controlling the speed, and detecting a derivative laid on a traveling path to travel. In the multi-axle automatic guided vehicle, in the front and rear direction of the vehicle body, while installing a guide sensor for normal traveling control for controlling traveling and steering of a plurality of wheel groups, respectively,
A traversing guide sensor for performing traversing and steering control in a direction perpendicular to the traveling direction is provided at a position separate from the traveling control guide sensor, and detects a marker disposed in front of a change point of the traveling state of the traveling line. A marker detector is attached to the vehicle body, and further, the traveling speed and the steering angle of each wheel of the traveling wheel device are determined based on signals from the guide sensor and the marker detector. A control device that always performs a calculation for controlling to the optimum speed and angle and outputs a command is provided, and a traveling drive mechanism and a steering mechanism that independently drive each wheel of the traveling wheel device according to a command from the control device are provided. A multi-axis automatic guided vehicle, which is connected to the traveling wheel device. (2) The multi-axis automatic guided vehicle according to (1), wherein at least a traverse guide sensor among the guide sensors is attached to the vehicle body so as to be liftable.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing an example of a multi-axis automatic guided vehicle according to the present invention (it is assumed that wheels are visible for convenience, although different from the actual case), and FIG. 2 is a front view of FIG. FIG. 3 is an enlarged detailed view of each wheel.

In the figure, reference numeral 1 denotes a multi-axis traveling axis (4 in the figure).
(Axle), the upper surface of which is provided with a concave receiving base 1a on which a heavy object (coil) 4 is loaded.
The illustrated example shows a vehicle body on which three coils are mounted. 3a
Reference numerals 3h to 3h denote running wheels attached to the lower part of the vehicle body 1, and in the illustrated example, are eight-wheel type wheels each including two tires. Reference numerals 2a and 2b denote travel control guide sensors installed at arbitrary positions before and after the vehicle body 1, for example, at the center of the front four wheels and at the center of the rear four wheels.
2a is the front sensor when the transport vehicle moves in
2b is a rear sensor, and when traveling to the right (in the direction of arrow 10), 2b is a front sensor and 2a is a rear sensor.

Reference numeral 5 denotes a derivative laid on the ground, which is detected by the travel control guide sensors 2a and 2b, and travel control of the carrier is performed based on the detection signals. Reference numerals 6a and 6b denote traversing guide sensors which are installed almost in the middle of both sides of the vehicle body 1, and transfer the conveyed object 4 to a dedicated transfer table 12 (see FIG. 5 described later) or vice versa. This works when a conveyed object is delivered from the table. Further, reference numerals 7a and 7b denote marker detection sensors installed at each corner of the vehicle body 1 for detecting a marker 8 provided at a point just before a curve or a stop position and obtaining positional information necessary for the vehicle body. It is.

As shown in FIG. 3, each of the running wheels 3a to 3h has a running motor 13 and a steering motor 14, which are independent from each other, and can be controlled independently. The traveling motor 13 is directly connected to the wheel 3a via an appropriate gear, and the steering motor 14 turns the wheel 3a to an arbitrary angle via the drive transmission gear 16 and the rotary bearing 17 for steering. Reference numeral 18 denotes a suspension cylinder for the wheel 3a. Although not shown, each traveling wheel is provided with an encoder or an ABSOCODER that can measure the distance traveled by the carrier, and has a mechanism that can constantly grasp the vehicle body position. Not all wheels need to be drive wheels, and it is sufficient that at least four wheels (for example, wheels on the front and rear sides of the vehicle body) are drive wheels, and the rest need only have a steering mechanism.

The traversing guide sensors 6a, 6b
May be installed on any part of the vehicle body, but when the transport vehicle travels in the traveling direction, it comes into contact with the ground road surface due to unevenness of the traveling road surface, uneven load of the load 4 on the transport vehicle, tire wear, etc. There is a possibility that this is more likely as the vehicle body length increases. FIG. 4 shows a structure for coping with such a situation. As an example of mounting the traversing guide sensor 6a to the vehicle body 1, a guide sensor pulling device 15 in the form of a cylinder is interposed between the guide sensor and the vehicle body. 6a can be separated from the ground. This can prevent the guide sensor from contacting the ground road surface.

The above-described guide sensor pulling structure may be provided on only one of the guide sensors depending on conditions such as road surface conditions and vehicle length. Further, when there is a possibility that the same situation may occur in the traveling guide sensor during the traversing, the same structure can be adopted also in the traveling guide sensor.

Hereinafter, the operation of the automatic guided vehicle according to the present invention will be described. FIG. 5 shows a traveling road surface including straight lines and curves, and a transport vehicle. The carrier 1 can travel in any direction by switching the driving direction of each of the traveling wheels 3a to 3h when traveling in the direction of arrow 9 and when traveling in the direction of arrow 10. FIG. 5 shows a case where the vehicle travels in the direction 9. First, the carrier travels according to a given command, and when the detection sensor 7b detects the marker 8 just before the curve, the traveling speed and the steering angle of each traveling wheel 3a to 3h are determined in advance after a predetermined distance. Control to the determined curve running pattern.

At this time, in the case of a transport vehicle having multi-axis traveling wheels, the conventional four-wheel vehicle may be used due to various factors such as lengthening of the vehicle body length, transportation of heavy objects, uneven load of the transported object, and wear of traveling wheels. The vehicle body is more likely to deviate from the line of the derivative 5 than the wheel carrier. In order to solve this problem, in the present invention, as described above, the front-side guide sensor 2a controls the wheel group of 3a to 3d, and the rear-side guide sensor 2b controls three wheels.
The control of the wheel group from e to 3h is performed. 7 and 8 show control block diagrams according to the present invention.

As shown in FIG. 7, the carrier control device includes a marker detector, a signal from a speed detector and a traveling distance detector connected to the traveling motor 13, and a signal from the front and rear direction guide sensors 2a and 2b. Detection signal, steering motor 14
A signal from a steering angle detector connected to the vehicle is input, and the traveling speed, the vehicle body position, and the steering angle of the transport vehicle are constantly grasped. Then, based on the installation positions of the guide sensors 2a and 2b in the vehicle body and the relative positional relationship between the multi-axis wheels to be controlled, the optimum traveling speed and steering angle of each traveling wheel that changes every moment are determined at the time. A control constant is selected in a control loop in consideration of a calculation speed of a computer provided in the control device, and an appropriate drive command is output to control each traveling wheel.
Furthermore, each traveling wheel 3a driven based on a driving command
And data fed back from the driving mechanism and the steering mechanism for a predetermined period of time,
Comparing and calculating the position signals a and 2b, comparing the optimal control constant matching the ever-changing traveling condition with the target value, performing feedback control again in the control loop, and correcting and outputting the optimal control command. And I try to run stably even on curves.

FIG. 8 shows various control commands (solid arrows) for each traveling wheel and input of actual values (dashed arrows) from each traveling wheel in the control device of the carrier. From the traveling parameter determination unit to the front wheel and rear wheel traveling control unit, the speed target value A,
The control parameter B and the front / rear guide sensor position information C are sent, respectively, and the front wheels (3a to 3d) are transmitted from the traveling control unit to the front wheels and the rear wheels via the speed control unit and the distribution unit for each axis. Speed command D and its distribution command E, front wheel (3
a to 3d) Steering command F and its distribution command G, rear wheels (3e to 3e)
3h) Speed command H and its distribution command I, rear wheels (3e to 3e)
h) The steering command J and its distribution command K are output, and the respective running wheels travel and are steered in response thereto. In addition, a front wheel (3a to 3d) actual speed value and a steering actual value L, a rear wheel (3e to 3h) actual speed value and a steering actual value M are sent from each traveling wheel to the traveling control unit, and a traveling guide sensor is provided. 2a,
From 2b, deviation deviation amounts O and P of the front and rear wheel guide sensors from the travel guide line 5 are sent. In the present invention, the positional deviation information of the front wheel side and rear wheel side guide sensors is mutually sent to the traveling control unit of the other side.

FIG. 6 shows a state in which the load 4 is received from the dedicated transfer table 12 (or is transferred to the transfer table). In this case, the directions of the traveling wheels 3a to 3h are steered. The mechanism is driven to change the angle by 90 °, and the guide line 11 orthogonal to the guide line 5 is detected by the traverse guide sensors 6a and 6b at the lower part of the vehicle body.
Is detected, and the transport vehicle 1 is caused to traverse based on a control method similar to the above-described travel control. The load 4 placed on the overhanging portion of the gate is transferred to the carrier by raising a lifter incorporated in the carrier that has entered below.

By the control method described above, it is possible to eliminate the eccentric load and reduce the load on the traveling path, etc., and to move the heavy object with high speed and stability by the multi-axis automatic guided vehicle. Make it possible.

[0020]

As described above, according to the present invention, a multi-axle automatic guided vehicle loaded with heavy objects can perform straight running and traversing at high speed and stably, and can also maintain the vehicle body in curved running. A stable traveling is possible by avoiding an eccentric load, and an optimal transport vehicle can be provided even for the transport of heavy loads.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a multi-axis automatic guided vehicle according to the present invention.

FIG. 2 is a front view of FIG. 1, showing a state in which coils are loaded.

FIG. 3 is an enlarged detailed view of each wheel in FIG. 1;

FIG. 4 is a diagram showing a specific example of a guide sensor pulling mechanism in the carrier of FIG. 1;

FIG. 5 is an explanatory plan view showing a state in which the carrier according to the present invention travels on a travel path including a curve.

FIG. 6 is an explanatory view of the traversing of the transport vehicle and the state of transfer of the load according to the present invention.

FIG. 7 is a control block diagram for explaining overall traveling / steering control including the transport vehicle of the present invention.

FIG. 8 is a control block diagram for explaining traveling control of the transport vehicle itself according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Car body 2a, 2b Traveling guide sensor 3a-3h Running wheel 4 Conveyed object (coil) 5 Traveling guide line 6a, 6b Traversing guide sensor 7a-7d Marker detector 8 Marker 9,10 Transportation vehicle traveling direction 11 Guide line for traverse 12 Transfer stand 13 Traveling motor 14 Steering motor 15 Guide sensor pull-up device 16 Drive transmission gear 17 Rotary bearing 18 Suspension cylinder

Claims (2)

[Claims] 1. It has six or more wheels with three or more axes in the front-rear direction,
In a multi-axis automatic guided vehicle that travels by detecting a derivative laid on a traveling path and having a traveling wheel device capable of independently controlling the speed with at least four of the driving wheels as driving wheels, A guide sensor for normal traveling control for controlling the traveling and steering of the wheel group is installed, and a traversing guide sensor for performing traversing and steering control in a direction perpendicular to the traveling direction is provided at a position different from the traveling control guide sensor. And a marker detector for detecting a marker disposed in front of the change point of the traveling state of the traveling line is attached to the vehicle body.Furthermore, based on signals from the guide sensor and the marker detector, the traveling wheel device To determine the running speed and steering angle of each wheel, and to always control the optimum speed and angle in response to the ever-changing running conditions. A control device for performing calculations and outputting instructions is provided, and a traveling drive mechanism and a steering mechanism for independently driving each wheel of the traveling wheel device according to instructions from the control device are connected to the traveling wheel device. Multi-axis automatic guided vehicle. 2. The multi-axis automatic guided vehicle according to claim 1, wherein at least one traverse guide sensor of the guide sensors is attached to the vehicle body so as to be pulled up.