JPH09109879A - Mobile truck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly achieve advancement into a pallet and evacuation from the pallet without being affected by the skill of an operator. SOLUTION: A mobile truck is provided with a programmable controller to control each part of a device, a magnetic guide tape 10 provided on a back side of a loading table 9c of a pallet 9, guide sensors 6-8 which are provided on a platform 4c of a mobile truck 4 and respectively detect the magnetic guide tape 10, and a direction detector to detect the direction of the mobile truck 4. During the advancement, the programmable controller realizes the steering control of drive wheels 51-512 so that the positional deviation of the guide sensors 6-8 relative to the magnetic guide tape 10 is within the allowable value. During the evacuation, the drive wheels 51-512 are steered so that the positional deviation Is below the allowable value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-propelled carriage used for carrying heavy objects.

[0002]

2. Description of the Related Art FIG. 9 is a diagram showing the configuration of a pallet transfer system used for transferring heavy objects such as large steel materials.
In FIG. 9A, reference numeral 1 denotes a pallet,
Are mounted on the mounting table 1a, and leg members 1b, 1b,... Attached to four corners of the lower surface of the mounting table 1a are integrally formed. Reference numeral 3 denotes a self-propelled carriage having twelve drive wheels, which carries the heavy objects 2 together with the pallets 1 on a carrier 3a.

In the above structure, first, the driver
As shown in (a), the self-propelled carriage 3 is moved under the mounting table 1a of the pallet 1 to be transported. Next, the driver
As shown in FIG. 9B, a switch (not shown) in the driver's cab is operated to raise the vehicle height of the self-propelled carriage 3, the pallet 1 is loaded on the loading platform 3a, and then the self-propelled carriage 3 is set to the destination. Drive up to.

When the driver arrives at the destination, the driver
As shown in (c), the vehicle height of the self-propelled carriage 3 is lowered by operating the switch, and the pallet 1 is placed at the location. Then, as shown in FIG. Escape and proceed to load pallet 1 again.

[0005]

By the way, when the conventional self-propelled carriage 3 is inserted into the lower part of the pallet 1 (see FIG. 9).
(Refer to (a)), since the driver is driving the self-propelled carriage 3 into the lower part of the pallet 1 with a can while looking at the rearview mirror, when an inexperienced driver or the like performs the above-mentioned driving operation, There is a problem that the self-propelled carriage 3 is applied to the leg member 1b. Also, when pulling out the self-propelled carriage 3 from the pallet 1, the driver uses the can to escape the self-propelled carriage 3 from the pallet 1. There was a problem of hitting the carriage 3. The present invention has been made against such a background, and provides a self-propelled carriage that can smoothly enter and exit a pallet without being influenced by the skill level of a driver. The purpose is to do.

[0006]

According to a first aspect of the present invention, a pallet having a mounting table on which a heavy object is mounted and legs supporting the mounting table is inserted into the pallet to move the pallet. In a self-propelled carriage having a plurality of drive wheels, which is loaded on its own bed and conveyed, a guide tape provided on a lower surface of the mounting table of the pallet along a centerline in the longitudinal direction of the pallet, and the self-propelled vehicle. Guide tape detecting means for detecting the guide tape, which is provided on the carrier of the carriage on the center line of the vehicle body, and a plurality of steering drives that are provided corresponding to the plurality of drive wheels and drive the plurality of drive wheels by steering. Means and, when the steering control of the plurality of drive wheels is in the first control mode at the time of entering the pallet, based on the detection result of the guide tape detecting means. Position shift amount calculating means for obtaining the position shift amount of the guide tape detecting means with respect to the guide tape, and a tangent line of each circle whose radius is each distance from the point determined by the position shift amount to the plurality of drive wheels. Steering angle calculation means for respectively obtaining steering angles of the plurality of drive wheels facing each other, wherein the steering drive means is calculated by the steering angle calculation means so that the displacement amount becomes equal to or less than an allowable value. A self-propelled carriage, wherein each of the plurality of driving wheels is steered at each steering angle.

According to a second aspect of the present invention, a pallet having a placing table on which a heavy object is placed and legs supporting the placing table is inserted into the pallet, and the pallet is loaded on its own loading platform. In a self-propelled trolley that has multiple drive wheels,
A guide tape provided along the center line in the longitudinal direction of the pallet on the lower surface of the mounting table of the pallet, and provided on the luggage carrier of the self-propelled carriage at regular intervals along the vehicle body center line, A plurality of guide tape detection means for detecting the guide tape, a plurality of steering drive means provided corresponding to the plurality of drive wheels, respectively, for steering the plurality of drive wheels, and when entering the pallet. When the steering control of the plurality of drive wheels is in the first control mode, the first guide for the guide tape is first detected based on the detection result of the first guide tape detecting means that first detects the guide tape. A first positional deviation amount calculating means for obtaining a first positional deviation amount of the tape detecting means; and a first positional deviation amount determined by the first positional deviation amount. And a first steering angle calculating means for determining steering angles of the plurality of drive wheels facing the tangential direction of each circle whose radius is each distance from the point to the plurality of drive wheels, and when entering the pallet. , When the steering control of the plurality of drive wheels is in the first control mode,
Second displacement amount calculating means for determining a second displacement amount of the second guide tape detecting means with respect to the guide tape based on a detection result of the second guide tape detecting means closest to the entrance of the pallet. And a radius from a second point determined by the second displacement amount to a plurality of drive wheels located behind the second guide tape detecting means in the traveling direction. Second steering angle calculating means for respectively determining steering angles of the plurality of drive wheels oriented in the tangential direction of the circle, wherein the steering drive means is configured such that the first displacement amount is equal to or less than an allowable value. When the second steering angle is obtained by steering the plurality of drive wheels with the respective steering angles obtained by the first steering angle calculation means, the second positional deviation amount becomes equal to or less than the allowable value. To become the first Autonomous guided vehicle, characterized in that each steering drive a plurality of drive wheels located beyond the second guide tape detecting means at each steering angle obtained by the steering angle calculating means.

According to a third aspect of the present invention, in the self-propelled carriage according to the first or second aspect, there is provided azimuth detecting means for detecting a azimuth to which the self-propelled trolley is facing, and when escaping from the pallet. When the steering control of the plurality of drive wheels is in the second control mode, the difference between the detection result of the azimuth detecting means immediately before the escape and the azimuth detection result during the escape is obtained as the azimuth deviation angle. An azimuth deviation angle calculating means is provided, and the steering driving means drives each of the plurality of drive wheels by steering so that the azimuth deviation angle is equal to or less than an allowable value.

According to a fourth aspect of the present invention, in the self-propelled carriage according to any one of the first to third aspects, the guide tape is a magnetic guide tape in which a tape band of a magnetic material is magnetized. The guide tape detecting means is composed of a plurality of magnetism detecting means for detecting magnetism.

According to a fifth aspect of the present invention, in the self-propelled carriage according to any of the first to third aspects, the guide tape is a light reflection guide tape that reflects light, and the guide tape detecting means is provided. , A plurality of light emitting and receiving means.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an external configuration of a self-propelled carriage and a pallet according to an embodiment of the present invention. In this figure, 4 is 12 drive wheels 51
The self-propelled carriages 4 to 512 each have a front cab 4a and a rear cab 4b at the front and rear portions thereof. Reference numerals 6 to 8 are guide sensors for detecting a magnetic guide tape 10 described later, and are attached to the loading platform 4c of the self-propelled carriage 4 at the front portion, the central portion and the rear portion along the vehicle body center line Lb.

As shown in FIG. 2, the guide sensor 6 is composed of Hall elements 61 to 66 provided at regular intervals in the width W direction of the magnetic guide tape 10.
These Hall elements 61 to 66 detect the magnetism of the magnetic guide tape 10. The guide sensors 7 and 8 are similar to the guide sensor 6 in that the Hall elements 71 to 76 and 81
-8 6 respectively.

In FIG. 1, reference numeral 9 denotes a pallet, which is integrally formed with legs 9a and 9b and a platform 9c supported by the legs 9a and 9b and on which a heavy object (not shown) is placed. It will be. Place 9 for this pallet 9
A magnetic guide tape 10 is attached to the center of the back surface of c along the center line La. This magnetic guide tape 10
A tape made of a magnetic material is magnetized,
It serves to guide the self-propelled carriage 4 when the self-propelled carriage 4 enters the pallet 9.

FIG. 3 is a block diagram showing the electrical construction of the control unit of the self-propelled carriage according to this embodiment. In this figure, 11 is a diesel engine. Reference numeral 12 is a brushless generator that is directly connected to the rotating shaft of the diesel engine 11, and outputs an AC voltage vR and an AC voltage vS via the reactor 16. A programmable controller 13 controls each part of the apparatus.
The operation of the programmable controller 13 will be described later.

141 to 1412 are self-propelled carriages 4 shown in FIG.
Is an induction motor for steering provided corresponding to each of the driving wheels 51 to 512, and drives the driving wheels 51 to 512 by steering. 151-1512 are induction motors 1
41 to 1412 are vector inverters provided by corresponding to vector control, and induction motors 141 to 1
The AC voltages vS1 to vS12 are supplied to 412, respectively. The vector inverters 151 to 1512 have vector control signals S1 to S1 supplied from the programmable controller 13.
AC voltages vS1 to vS12 having phases and frequencies corresponding to 2 are generated and output to the induction motors 141 to 1412, respectively.

171 to 1712 are drive wheels 51 to 512 (see FIG. 1).
(Refer to FIG. 3), each of which is an induction motor for traveling and drives the drive wheels 51 to 512 to rotate. 181-1
Reference numeral 812 is a vector inverter provided corresponding to each of the induction motors 171 to 1712.
AC voltages vR1 to vR12 are supplied to 1712, respectively. The vector inverters 181 to 1812 have vector control signals R1 to R12 supplied from the programmable controller 13.
AC voltage vR1 to vR12 with phase and frequency according to R12
Are generated and output to the induction motors 171 to 1712, respectively.

191 to 1912 are potentiometers provided corresponding to the drive wheels 51 to 512, respectively.
The programmable controller 1 detects the steering angles of 1 to 512 and outputs the detection results as steering angle signals Sθ1 to Sθ12.
Feedback to 3 respectively. Reference numerals 201 to 2012 denote pulse generators provided respectively corresponding to the drive wheels 51 to 512, generate pulse signals having a cycle corresponding to the rotation speeds of the drive wheels 51 to 512, and rotate speed signals Sω1 to Sω12.
As feedback to the programmable controller 13.

The guide sensor 6 includes Hall elements 61 to 66.
Each of them (see FIG. 2) is directly below the magnetic guide tape 10, and when the magnetism of the magnetic guide tape 10 is detected, the ON signals S61 to S66 are output to the programmable controller 13. Similar to the guide sensor 6, the guide sensors 7 and 8 output ON signals S71 to S76 and S81 to S86 to the programmable controller 13, respectively. Reference numeral 30 denotes an azimuth detector provided in the front cab 4a or the rear cab 4b (see FIG. 1), and outputs the detected azimuth as azimuth data DH to the programmable controller 13.

Reference numeral 21 is an operation section provided in the front cab 4a of the self-propelled carriage 4 shown in FIG. In the operation unit 21, 22 is a programmable controller, which controls each unit of the device in the operation unit 21. Reference numeral 23 is a handle for changing the traveling direction of the self-propelled carriage 4. An encoder 24 detects the rotation angle of the steering wheel 23 and outputs the detection result to the programmable controller 22 as a steering angle target value Sθ. The programmable controller 22 is
The steering angle target value Sθ and the displacement amount of an accelerator pedal (not shown) (hereinafter referred to as the accelerator amount), that is, the speed target value Sω are output to the programmable controller 13.

Reference numeral 25 denotes a switch operated by the driver to switch the steering control mode. The above-mentioned modes include a normal steering mode used during normal driving, an entry steering mode and an exit steering mode, which will be described later. is there.

Reference numeral 26 is an indicator lamp for displaying information necessary for driving. A powder brake 27 serves to apply a weight to the handle 23 by braking the rotation of the shaft of the handle 23. Reference numeral 28 denotes a weight switching unit, which switches the weight to the handle 23 under the control of the programmable controller 22. 29 is
The operation unit is provided in the rear cab 4b of the self-propelled carriage 4 shown in FIG. 1, and has the same configuration as the operation unit 21 described above.

<Pallet entry operation> Next, the operation of the self-propelled carriage according to the present embodiment described above will be described. First, in FIG. 1, when the self-propelled carriage 4 enters the pallet 9, the driver in the front cab 4a stops the self-propelled carriage 4 before the entrance 9d of the pallet 9.
Now, as shown in FIG. 1, slightly tilting with respect to the pallet 9,
It is assumed that the self-propelled carriage 4 is stopped. The switch 25 (see FIG. 2) of the self-propelled carriage 4 is set to the normal steering mode, and the drive wheels 51 to
It is assumed that the steering angle of 512 is 0.

In this state, when the driver switches the switch 25 (see FIG. 3) to the entry steering mode, the programmable controller 22 outputs a signal S corresponding to the entry steering mode to the programmable controller 13. Thereby, the programmable controller 13 recognizes that the steering mode at the time of approach is set. Subsequently, when the driver depresses an accelerator pedal (not shown), the programmable controller 22 (see FIG. 1) outputs a speed target value Sω corresponding to the accelerator amount to the programmable controller 13
Output to

As a result, the programmable controller 13 outputs the vector control signals R1 to R12 to the vector inverters 181 to 1812 so that the rotation speed signals Sω1 to Sω12 output from the pulse generators 201 to 2012 become the target speed values Sω. . Vector inverter 181
.About.1812 are the vector control signals R1 to R12 for the AC voltage vR.
To AC motors vR1 to vR12 having a phase and frequency corresponding to that and supplied to the induction motors 171 to 1712, respectively. As a result, the induction motors 171 to 1712 are rotationally driven, and the self-propelled carriage 4 travels in the direction of arrow A shown in FIG.

Now, as shown in FIG. 4, the front end portion of the self-propelled carriage 4 approaches the end portion of the pallet 9, and as shown in FIG. 5, the Hall elements 61 and 62 of the guide sensor 6 are magnetic guide tapes 10. Hall element 6 not located directly below
Assuming that 3 to 66 are located directly below the magnetic guide tape 10, the guide sensor 6 outputs ON signals S63 to S66 (see FIG. 3) corresponding to the Hall elements 63 to 66 to the programmable controller 13.

As a result, the programmable controller 13 recognizes that the guide sensor 6 is displaced leftward with respect to the magnetic guide tape 10 by the positional displacement amount D1 (see FIG. 5). Then, the programmable controller 13 obtains the steering angle θ1 (see FIG. 4) of the drive wheels 51 according to the positional deviation amount D1 so that the positional deviation amount D1 is equal to or less than the allowable value. Then, the programmable controller 13
The position of a point X1 at which the perpendicular L1 to the drive wheel 51 when the drive wheel 51 has a steering angle θ1 and the center line Lc in the direction perpendicular to the longitudinal direction of the self-propelled carriage 4 is obtained.

Next, the programmable controller 13
Is the steering angle θ1 to θ1 of the drive wheels 52 to 512 other than the drive wheel 51.
2, the driving wheels 52 to 512 are respectively from the X1 point to the driving wheels 52 to 512.
It is calculated so as to face in the tangential direction of each circle whose radius is each distance up to 512.

Next, the programmable controller 13
Outputs the vector control signals S1 to S12 corresponding to the calculated steering angles θ1 to θ12 to the vector inverters 151 to 1512, respectively, while receiving the feedback from the potentiometers 191 to 1912. As a result, as shown in FIG. 4, the driving wheels 51 to 512 are steered in the tangential direction of each circle centered at the point X1 (hereinafter referred to as mirror steering), so that the self-propelled carriage 4 is shown in FIG. As indicated by the arrow B, the vehicle travels while correcting the deviation in the traveling path that draws an arc.

Also, during this traveling, the programmable controller 13 causes the programmable wheels 13 of the drive wheels 51 shown in FIG. 4 to change each time the ON signals (S61 to S66) output from the guide sensor 6 change, that is, the position shift amount changes. Correction calculation of the steering angle θ1, the position of the point X1, and the steering angles θ2 to θ12 of the drive wheels 52 to 512 is performed.

Then, the self-propelled carriage 4 enters the pallet 9 to the position shown in FIG. 6, and as shown in FIG. 7A, the Hall elements 61 and 62 of the guide sensor 6 are moved to the magnetic guide tape 1.
Assuming that the Hall elements 63 to 66 are located directly below the magnetic guide tape 10 and not directly below 0, as shown in FIG. 3, the guide sensor 6 outputs ON signals corresponding to the Hall elements 63 to 66, respectively. S63 to S66 are output to the programmable controller 13.

Simultaneously with the above operation, as shown in FIG. 7B, the Hall elements 71 to 73 of the guide sensor 7 are located immediately below the magnetic guide tape 10 and the Hall element 7 is located.
Assuming that 4 to 76 are not located directly under the magnetic guide sensor 10, the guide sensor 7 outputs ON signals S71 to S73 corresponding to the Hall elements 71 to 73 to the programmable controller 13 as shown in FIG. To be done.

The on signals S63 to S66 and S71 to S73
When is input, the programmable controller 13
As shown in FIGS. 7A and 7B, the guide sensor 6 is located to the left with respect to the magnetic guide tape 10 by a displacement amount D2, and the guide sensor 7 is displaced with respect to the magnetic guide tape 10. Recognize that the amount D3 is located to the right. Next, the programmable controller 13 steering-controls the drive wheels 51-512 as shown in FIG. 6 so that each of the positional deviation amounts D2 and D3 becomes equal to or less than the allowable value.

That is, the programmable controller 1
3, the steering angle θ1, the position of the X1 point of the drive wheel 51, the position of the drive wheel 52 to the drive wheel 52-in order to set the positional deviation amount D1 (see FIG. 7A) to the allowable value or less. After obtaining the steering angles θ2 to θ6 of each of 56, the potentiometers 191 to
While receiving the feedback from 196, the vector control signals S1 to S1 ...
S6 is output to each of the vector inverters 151 to 156. As a result, as shown in FIG. 4, the drive wheels 51 to 512
Is steered in the tangential direction of the X1 point and the circles centered on it.

At the same time, the programmable controller 13 sets the drive wheels 51 according to the positional deviation amount D2 so that the above-mentioned positional deviation amount D2 (see FIG. 7B) becomes equal to or less than the allowable value.
Determine the steering angle θ11 of 1. Next, the programmable controller 13 obtains the position of the point X2 where the perpendicular line L11 to the drive wheel 511 when the drive wheel 511 has the steering angle θ11 and the center line Lc of the self-propelled carriage 4 intersect.

Next, the programmable controller 13
Is the steering angle θ7-θ10, θ12 of the drive wheels 57-510, 512.
Are determined so that the drive wheels 57 to 510 and 512 face in the tangential direction of each circle whose radius is the distance from the point X2 to each drive wheel 57 to 510 and 512, respectively.

Next, the programmable controller 13
Outputs the vector control signals S7 to S12 corresponding to the calculated steering angles θ7 to θ12 to the vector inverters 157 to 1512, respectively, while receiving feedback from the potentiometers 197 to 1912. As a result, as shown in FIG. 4, the drive wheels 57 to 512 are respectively steered in the tangential direction of the circle centered at the point X2.

As described above, the drive wheels 51 to 56 are tangential to the circles centered at the point X1 and the drive wheels 57 to 512 are also tangential.
Is steered in the tangential direction of each circle centered on the point X2, so that the self-propelled carriage 4 travels while correcting the deviation in a traveling path that draws an arc as shown by an arrow C in the figure. The curvature of the arc shown by the arrow C is larger than the curvature of the arc shown by the arrow B in FIG. This is because, as shown in FIG. 6, since the X2 point is closer to the self-propelled carriage 4 than the X1 point, the driving wheels 57 to 512 have a larger steering angle than the driving wheels 51 to 56 corresponding to them. It is because it is done.

When the driver determines that the self-propelled carriage 4 has completely entered under the pallet 9 (see FIG. 8), the driver releases his leg from the accelerator pedal and depresses the brake pedal to move the self-propelled carriage 4 into position. Stop. Next, as described above, the driver operates the switch (not shown) in the driver's cab to raise the vehicle height of the self-propelled carriage 4, loads the pallet 9, and then operates the switch 25 (see FIG. 1). Switch to normal steering mode. As a result, the programmable controller 22 shown in FIG. 3 outputs the signal S corresponding to the normal steering mode to the programmable controller 13, and the programmable controller 13 recognizes that the normal steering mode has been set. Next, the driver runs the self-propelled carriage 4 to the destination by operating the steering wheel 23 and the accelerator pedal.

<Escape Operation from Pallet> When the vehicle arrives at the destination, the driver stops the self-propelled carriage 4. Now, as shown in FIG. 8, the self-propelled carriage 4 has its vehicle body center line Lb stopped in the true north direction, and the steering angles θ1 to θ12 of the drive wheels 51 to 512 are zero. And Subsequently, the driver lowers the vehicle height of the self-propelled carriage 4 by operating the switch and puts the pallet 9 on the place, and then the switch 25
Is switched from the normal steering mode to the steering mode when exiting. As a result, the signal S corresponding to the above-mentioned escape-time steering mode is output from the programmable controller 1 shown in FIG.
3 and the programmable controller 13 recognizes that the escape mode steering mode has been set.

Next, the programmable controller 13
Is the azimuth data DH output from the azimuth detector 13.
(Hereinafter referred to as reference direction data DH '),
Retain. Now, it is assumed that the reference azimuth data DH 'is data representing "true north". This reference direction data DH '
Is data representing the direction of the self-propelled carriage 4 immediately before the escape.

Then, as shown in FIG. 8, the driver depresses the accelerator pedal to let the self-propelled carriage 4 escape from the pallet 9. As a result, the self-propelled carriage 4 travels in the direction of arrow E shown in FIG. During this traveling, the programmable controller 13 shown in FIG.
Reads the azimuth data DH, compares the azimuth data DH with the reference azimuth data DH ', and if the two data match, the current steering angles θ1 to θ12 of the driving wheels 51 to 512 remain unchanged. To do.

On the other hand, the direction data DH is the reference direction data D
If deviated from H ', programmable controller 13
Calculates the azimuth deviation angle which is the difference between the two data. next,
The programmable controller 13 obtains the steering angle θ1 of the drive wheel 51 corresponding to the azimuth deviation angle so that the obtained azimuth deviation angle is equal to or less than the allowable value, and then performs the same operation as described above to drive the drive wheel 52 during mirror steering. The steering angles .theta.2 to .theta.12 of .about.512 are obtained respectively, and the drive wheels 51 to 512 are subjected to mirror steering control. In this way, the driving wheels 51 to 512 are automatically mirror-steered so that the azimuth deviation angle becomes equal to or less than the allowable value.
You can escape without hitting.

When the driver is in the rear cab 4b shown in FIG. 1, the guide sensor 8 is used during mirror steering control, and the guide sensor 7 is driven by the drive wheels 51.
Used for ~ 56 steering control.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and changes in design within the scope not departing from the gist of the present invention. Even so, it is included in the present invention. For example, in the above-described embodiment, an example in which the induction motors 141 to 1412 are used as means for steering the drive wheels 51 to 512 is shown, but the invention is not limited to this, and means for steering steering by hydraulic pressure may be used. You may use. In this case, instead of the brushless generator 12, a hydraulic pump,
An electromagnetic command valve may be used instead of the induction motors 141 to 1412, and an electromagnetic command valve amplifier may be used instead of the vector inverters 151 to 1512.

Further, in the above-described embodiment, 3
Although the example in which the individual guide sensors 6 to 8 are provided has been described, the present invention is not limited to this, and the cost may be taken into consideration.
The number may be four or four or more. In this case, X2
To obtain the point (see FIG. 6), the output of the guide sensor closest to the entrance 9d of the pallet 9 is used among the guide sensors outputting the ON signal. In addition, in the above-described embodiment, the Hall elements 61 to 66, 71 to 76.
And guide sensors 6 to 8 each consisting of 81 to 86
8. An example using the magnetic guide tape 10 has been described, but the present invention is not limited to this, and the Hall elements 61 to 66,
Light receiving and emitting elements may be used instead of 71 to 76 and 81 to 86, and a reflective tape that reflects light may be used instead of the magnetic guide tape 10. Further, in the above-described embodiment, the example in which the steering control is performed based on the azimuth data DH output from the azimuth detector 30 when the self-propelled carriage 4 escapes from the pallet 10 has been described. Instead of using the detector 30, the steering control may be performed based on the ON signals S61 to S66, S71 to S76, and S81 to S86 output from the guide sensors 6 to 8 by an operation reverse to that at the time of approach.

[0046]

As described above, according to the present invention,
Since each drive wheel is automatically steered when entering or leaving the pallet, the self-propelled carriage can be smoothly entered or exited without being influenced by the skill level of the driver.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an external configuration of a self-propelled carriage and a pallet according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view showing a configuration of guide sensors 6 to 8 shown in FIG.

FIG. 3 is a block diagram showing an electrical configuration of a control unit of the self-propelled carriage according to the embodiment of the present invention.

FIG. 4 is a plan view for explaining the operation of the self-propelled carriage according to the same embodiment when entering a pallet.

5 is a partially cut enlarged plan view showing the positional relationship between the guide sensor 6 and the magnetic guide tape 10 shown in FIG.

FIG. 6 is a plan view for explaining the operation of the self-propelled carriage according to the embodiment of the present invention when entering the pallet.

7 is a partially cut plan view showing a positional relationship between each of the guide sensors 6 and 7 and the magnetic guide tape 10 shown in FIG.

FIG. 8 is a plan view illustrating operations of the self-propelled carriage according to the embodiment of the present invention when entering the pallet and when escaping from the pallet.

FIG. 9 is a diagram showing a configuration of a conventional pallet transport system using a self-propelled carriage.

[Explanation of symbols]

 4 Self-propelled vehicle 6-8 Guide sensor 61-66, 71-76, 81-86 Hall element 9 Pallet 10 Magnetic guide tape 51-512 Drive wheel 13,22 Programmable controller 141-1412, 171-1712 Induction motor 151-1512 , 181 to 1812 Vector inverter 25 Switch 30 Direction detector θ1 to θ12 Steering angle S61 to S66, S71 to S76, S81 to S86 On signal DH Direction data La Center line Lb Body center line

Claims (5)

[Claims] 1. A plurality of drive wheels that enter under a pallet having a mounting table on which a heavy object is mounted and legs supporting the mounting table, and load and transport the pallet on its own bed. In a self-propelled carriage having, a guide tape provided along the center line in the longitudinal direction of the pallet on the lower surface of the mounting table of the pallet, and provided on the vehicle body center line on the luggage carrier of the self-propelled carriage, Guide tape detection means for detecting a guide tape, a plurality of steering drive means provided corresponding to the plurality of drive wheels for driving the plurality of drive wheels by steering, and a plurality of the plurality of steering drive means when entering the pallet. When the steering control of the drive wheels of the guide tape is set to the first control mode, the guide tape for the guide tape is detected based on the detection result of the guide tape detecting means. A positional deviation amount calculating means for obtaining a positional deviation amount of the tape detecting means; and the plurality of drives facing the tangential direction of each circle whose radius is each distance from the point determined by the positional deviation amount to the plurality of drive wheels. Steering angle calculating means for respectively obtaining steering angles of the wheels, wherein the steering driving means is configured to operate the plurality of steering angles at each steering angle calculated by the steering angle calculating means so that the positional deviation amount is equal to or less than an allowable value. A self-propelled trolley characterized by driving the drive wheels individually. 2. A plurality of drive wheels that enter under a pallet having a mounting table on which a heavy object is mounted and legs supporting the mounting table, and load and transport the pallet on its own bed. In a self-propelled carriage having, a guide tape provided on the lower surface of the mounting table of the pallet along the centerline in the longitudinal direction of the pallet, and at a constant interval along the vehicle body centerline on the luggage carrier of the self-propelled carriage. A plurality of guide tape detecting means for detecting the guide tape, and a plurality of steering drive means for steering the plurality of drive wheels, which are provided corresponding to the plurality of drive wheels, respectively. When entering the pallet, when the steering control of the plurality of drive wheels is in the first control mode, the first guide that first detects the guide tape Position deviation amount calculation means for obtaining a first position deviation amount of the first guide tape detection means with respect to the guide tape based on the detection result of the loop detection means, and determined by the first position deviation amount. First steering angle calculation means for respectively determining steering angles of the plurality of drive wheels facing the tangential direction of each circle whose radius is each distance from the first point to the plurality of drive wheels, and to the pallet When the steering control of the plurality of drive wheels is set to the first control mode at the time of entry of the guide tape, the guide tape for the guide tape is detected based on the detection result of the second guide tape detecting means closest to the entrance of the pallet. From a second position deviation amount calculating means for obtaining a second position deviation amount of the second guide tape detecting means and a second point determined by the second position deviation amount,
Secondly, the steering angle of each of the plurality of drive wheels facing the tangential direction of each circle whose radius is the distance to each of the plurality of drive wheels located rearward of the second guide tape detection means with respect to the traveling direction is obtained. Steering angle calculating means, wherein the steering driving means is configured to control the plurality of steering angles calculated by the first steering angle calculating means such that the first displacement amount is equal to or less than an allowable value. When each of the drive wheels is steered to obtain the second steering angle, the respective steering angles obtained by the second steering angle calculating means are set so that the second displacement amount becomes equal to or less than the allowable value. 2. A self-propelled carriage, characterized in that each of a plurality of drive wheels located rearward of the second guide tape detecting means is driven by steering. 3. An azimuth detecting means for detecting an azimuth in which the self-propelled carriage is facing, and when the steering control of the plurality of drive wheels is in a second control mode when the vehicle is escaping from the pallet. The steering drive means includes the azimuth deviation angle calculating means for obtaining a difference between the detection result of the azimuth detection means immediately before the escape and the azimuth deviation detection result during the escape, as the azimuth deviation angle calculation means. The self-propelled carriage according to claim 1 or 2, wherein each of the plurality of drive wheels is driven by a steering wheel so that is less than or equal to an allowable value. 4. The guide tape is a magnetic guide tape in which a tape band of a magnetic material is magnetized, and the guide tape detecting means is composed of a plurality of magnetic detecting means for detecting magnetism. The self-propelled carriage according to any one of claims 1 to 3, which is characterized in that. 5. The guide tape is a light-reflecting guide tape that reflects light, and the guide tape detecting means is composed of a plurality of light emitting and receiving means. The self-propelled carriage described in either one.