JPH08185225A - Automated guiding vehicle - Google Patents

Abstract

PURPOSE: To provide an automated guiding vehicle which can travel stably and economically without reference to a travel state. CONSTITUTION: The voltage generated by a tachometer generator 32 corresponding to the rotation frequency of the driving motor of a travel unit provided at the tail of the truck is converted by an A/D converter 53 into a driving wheel rotation frequency, which is inputted to a controller 51, and the traveling speed of the truck detected by a vehicle speed sensor 9 fitted to the truck is also inputted to the controller 51. Then the controller 51 judges that a slip is made unless the traveling speed of the truck corresponding to the driving wheel rotation frequency is reached, and grounds the front driving wheels of a travel unit provided at the head of the truck used in four-wheel driving mode by a motor 18 for elevation and performs control for driving their driving motors 34 and 41.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simple type automatic guided vehicle for carrying a load while detecting a guide zone on a road surface.

[0002]

2. Description of the Related Art Conventionally, as a simple type automatic guided vehicle,
It is known that a traveling unit having a pair of left and right driving wheels is attached to the lower surface side of a manual truck (for example,
(See Japanese Patent Publication No. 54005).

In this unmanned guided vehicle, in addition to the four non-driving wheels provided on the lower surface side of the truck, a traveling unit is provided substantially between the driven wheels in front of the four driving wheels to guide the vehicle on the road surface. By controlling the drive of the drive wheels while detecting the belt by the detection sensor, it is possible to run unmanned along the guide belt.

[0004]

By the way, when the unmanned carrier is actually used, there is a slope on the road surface on which the vehicle is to be run, or when a heavy object is towed and carried. However, there is a problem in that the drive wheels may slip, and due to the slips, the drive control of the drive wheels cannot be performed, and the vehicle deviates from the regular track, and further, the vehicle cannot run.

On the other hand, the traveling unit having a pair of left and right driving wheels described above is provided at the front and rear of the lower surface of the bogie so that it can be driven by four wheels, slip is prevented, and stable road surface is maintained. Things such as securing driving are performed.

However, in the case of four-wheel drive, the number of drive motors used is doubled, which inevitably leads to an increase in power consumption, and frequent battery replacement work reduces work efficiency. In order to reduce the battery replacement work, there is a new problem that the battery capacity must be increased or the number of installed batteries must be increased.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide an automatic guided vehicle capable of stable and economical traveling regardless of traveling conditions. To provide.

[0008]

The present invention for attaining the above object provides, in the invention according to claim 1, traveling by driving wheels and loading a load while detecting an induction zone on a road surface. In an unmanned guided vehicle for carrying, a pair of left and right drive wheels are respectively arranged in front of and behind the bogie, a detection means for detecting a traveling state of the bogie, and a driving force of drive wheels arranged in front and rear of the bogie. Based on the detection value of the switching means for switching between the four-wheel drive mode in which the trolley is driven by the vehicle and the two-wheel drive mode in which the trolley is driven by the driving force of the drive wheels arranged in front of or behind the trolley, and the detection value of the detection means. And a control means for controlling the switching means.

According to a second aspect of the present invention, in the configuration of the automatic guided vehicle according to the first aspect, the detection means includes a drive wheel rotation speed detection section for detecting a rotation speed of the drive wheel. And a vehicle speed detection unit that detects a traveling speed of the carriage.

According to a third aspect of the present invention, in the configuration of the unmanned transport vehicle according to the first aspect, the detecting means is connected to the vehicle and the load applied by pulling the towed object. It is a traction load detection unit that detects

According to a fourth aspect of the present invention, in the configuration of the automatic guided vehicle according to any one of the first to third aspects, the switching means abuts or separates the drive wheels from a road surface. It is characterized in that it is provided with an elevating mechanism section for making it.

According to a fifth aspect of the present invention, in the configuration of the automatic guided vehicle according to any one of the first to third aspects, the switching means includes the drive wheel and a drive section for driving the drive wheel. It is characterized in that it is a clutch for transmitting or interrupting a driving force interposed therebetween.

[0013]

According to the present invention thus constituted, in the invention described in claim 1, the detected value of the traveling condition of the truck detected by the detecting means is input to the control means. The control means controls the operation of the switching means for switching between the four-wheel drive mode and the two-wheel drive mode based on the detected value of the traveling condition. In this way, stable traveling is ensured by setting the four-wheel drive mode only when necessary according to the traveling situation, and during normal operation it is steady traveling in the two-wheel drive mode to reduce power consumption and economical traveling. Is done.

According to the second aspect of the present invention, the control means is supplied with the rotational speed of the drive wheel detected by the drive wheel rotational speed detection section and the actual traveling speed of the trolley detected by the vehicle speed detection section. When the traveling speed of the trolley does not correspond to the drive wheel rotation speed, it is determined that slip has occurred, and control is performed to switch to the four-wheel drive mode.

According to the third aspect of the invention, when the traction load detected by the traction load detection unit exceeds a preset reference value, the mode is switched to the four-wheel drive mode and the drive wheels slip. Is prevented in advance.

In the invention according to claim 4, the switching between the four-wheel drive mode and the two-wheel drive mode is performed by bringing the drive wheels into contact with or away from the road surface by the elevating mechanism section, which is necessary. Only in this case, the drive wheels for four-wheel drive are brought into contact with the road surface.

According to another aspect of the present invention, switching between the four-wheel drive mode and the two-wheel drive mode is performed by transmitting or cutting off the drive force from the drive unit by the clutch, and when necessary. Only the drive wheels for four-wheel drive are quickly connected and driven with the drive.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a side view showing a schematic configuration of an automated guided vehicle according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view showing a traveling unit shown in FIG. 1, and FIG. 3 is a traveling shown in FIG. It is the figure seen from A of a unit.

As shown in FIG. 1, the unmanned carrier vehicle of the present embodiment (hereinafter, also simply referred to as a carrier) includes traveling units 2 and 2 having a pair of left and right driving wheels on the lower surface of a base plate 1 in the front and rear direction. Each one is attached by screwing. The carriage is conveyed in the direction B in the figure, and for convenience sake, the following description will be given with the direction B in the figure as the front and the opposite direction as the rear. A pair of left and right rotatable non-driving wheels 3, 3 are attached to the lower surface side rear of the base plate 1, while a pair of left and right vertically rotatable and rotatable members are attached to the lower surface side front of the base plate 1. Non-driving wheels 4, 4 are attached. In the present embodiment, a vehicle speed sensor 9 which is a vehicle speed detection unit for detecting the traveling speed of the bogie is provided in front of the bogie. The vehicle speed sensor 9 is, for example, a laser speedometer that detects a speed by receiving a speckle pattern generated by irradiating a road surface with a laser beam and calculating a movement amount.

A handle 5 is provided upright on the rear upper surface side of the base plate 1, and both of the drive wheels of the traveling units 2 and 2 are manually operated by separating them from the road surface by a switching means which will be described later. It can also be used as a carrier. Also, handle towed items such as luggage and other trolleys.
It is also possible to pull by connecting to. This handle 5
At the rear of the control panel 6 including a controller or the like which is a control means for controlling the operation of the traveling units 2 and 2.
Is installed. Further, the traveling unit 2 is provided behind the base plate 1.
A battery 7 for supplying electric power to a drive motor described later is provided. The reference numeral "8" in the figure is a weight for maintaining the stability of the truck.

The traveling units 2 provided at the front and rear of the bogie, respectively, have the same structure, and as shown in FIG. 2, have a mounting member 11, and the upper surface of the mounting member 11 is the base plate of the bogie. 1 is abutted on the lower surface side of 1 and screwed with a bolt (not shown) to be attached. The rocking member 12 is rotatably supported by the pin 13 by the pin 13 and is constantly urged downward by a compression coil spring 14 in the drawing. The protruding portion 1 provided on the mounting member 11
5 is engaged with the long hole 16 formed in the rocking member 12,
Rotation of the swing member 12 around the pin 13 with respect to the mounting member 11 is restricted.

A lifting motor 18 is attached to the bracket 11a fixed to the mounting member 11, and a disc 19 fixed to the main shaft of the lifting motor 18 is attached.
A cam 20 is rotatably provided in the vicinity of the outer circumference of the. When the drive wheels 35 and 45 are separated from the road surface, the lifting / lowering motor 18 is driven to position the cam 20 upward, thereby pushing up the engagement bracket 12a fixed to the swing member 12. It is like this.

In the present embodiment, an elevating mechanism portion composed of an elevating motor 18, a disc 19, a cam 20, and an engaging bracket 12a of the traveling unit 2 provided in front of the bogie and the swinging member 12 are used. A four-wheel drive mode in which a switching means is configured and the bogie is driven by the driving force of both drive wheels arranged in front of and behind the bogie by the switching means, and the bogie is driven by the driving force of the drive wheels arranged behind the bogie. The mode is switched to the two-wheel drive mode for driving. Therefore, in the case of the four-wheel drive mode, the switching means of the traveling unit 2 provided in front of the truck lowers the drive wheels 35, 45 to bring them into contact with the road surface, that is, the traveling provided in front of the truck. The unit 2 is used for the four-wheel drive mode. Incidentally, conversely, it is of course possible to employ a configuration in which the traveling unit 2 provided at the rear of the truck is used for the four-wheel drive mode.

A traveling portion 21 is provided below the swinging member 12, and an opening 1 is formed in a substantially central portion of the swinging member 12.
A shaft portion 23, which is erected on a substantially central portion of the holding plate 22, is pivotally engaged with the support member 7. The rotation direction of the shaft portion 23 is always biased by a predetermined elastic force by an elastic member (not shown) so that the carriage is driven forward. An optical sensor 25 is installed in front of the holding plate 22,
As shown in FIG. 3, the optical sensor 25 is composed of three sensors. When the truck is traveling on the regular track, these three sensors are located above the width of the guide band 27, which is a reflector provided on the road surface, and the guide band 2
The reflected light from 7 can be received.

A casing 26 is provided on the holding plate 22 so as to be swingable in the left-right direction by pins 24, 24 provided at the front and rear. As a result, even if the road surface is slightly bent in the direction orthogonal to the traveling direction, it is possible to cope with it. A drive motor 31 is provided in the casing 26,
As schematically shown in FIG. 4, it is configured to drive the drive wheel 35 on the right side in the traveling direction via the tacho-generator 32 as a drive wheel rotation speed detection unit, the speed reducer 33, and the transmission unit 34. It Similarly, the driving wheel 45 on the left side in the traveling direction is used for the tacho generator 4
2, driven by the drive motor 41 via the speed reducer 43 and the transmission unit 44, and the left and right drive wheels are independently controlled. Then, the optical sensor 25 detects a deviation of the carriage from the guide band 27,
Running along the guide band 27 is realized by stopping the rotation of the drive motor of the drive wheel on the opposite side of the shifted direction.

In this embodiment, the tacho generator 3 is used.
Voltages corresponding to the rotation speeds of the drive motors 31 and 41 can be detected by the reference numerals 2 and 42, whereby the rotation speeds of the drive wheels 35 and 45 can be known. Here, the tacho generators 32 and 42 of the traveling unit 2 arranged at the rear of the truck and the vehicle speed sensor 9 constitute a detecting means for detecting the traveling state of the truck in the present invention. The transmission parts 34 and 44 are not limited to the configuration of the toothed pulley and the timing belt as shown in the figure, but may be configured to transmit power by meshing gears, for example. As shown in FIG. 5, the rotational speeds of the drive wheels 35 and 45 are obtained by directly detecting the teeth of a toothed pulley or gear fixed to the shafts of the drive wheels 35 and 45 by a sensor 52 such as a proximity sensor. It is also possible to perform F / V (frequency / voltage) conversion of the pulse waveform signal, further A / D convert it, and input it to the controller 51 for measurement.

FIG. 6 is a block diagram of switching control between the four-wheel drive mode and the two-wheel drive mode in this embodiment. The analog voltage corresponding to the rotation speed of the drive motor generated in the tacho generator 32 of the traveling unit 2 provided at the rear of the truck is converted into the drive wheel rotation speed by the A / D converter 53 and input to the controller 51. The traveling speed of the truck detected by the vehicle speed sensor 9 attached to the front of the truck is input to the controller 51. Then, the controller 51 detects the occurrence of the slip of the driving wheels based on the determination as to whether the traveling speed of the vehicle corresponds to the rotational speed of the driving wheels, thereby detecting the front of the vehicle used in the four-wheel drive mode. The operation of the raising / lowering motor 18 and the driving motors 31 and 41 of the traveling unit 2 provided in the above is controlled.

Next, the operation of this embodiment will be described with reference to the flow chart of switching operation between the four-wheel drive mode and the two-wheel drive mode shown in FIG. First, a start switch (not shown) is turned on to determine whether or not the vehicle is in a traveling state (step S1). When the vehicle is traveling, a driving motor 31 for the traveling unit 2 provided at the rear of the vehicle, Four
The drive wheel rotation speed corresponding to the output value of the tacho generator 32 connected to 1 is detected (step S2). Based on this drive wheel rotational speed, the controller 51 calculates the estimated traveling speed of the truck when there is no slip of the drive wheels with the road surface (step S3). On the other hand, the vehicle speed sensor 9 detects the actual traveling speed of the truck (step S4).

Next, the controller 51 proceeds to step S4.
It is determined whether or not the actual traveling speed of the trolley obtained in step S3 is lower than the assumed traveling speed of the trolley obtained in step S3 by a preset value or more (step S5). If it is determined that the actual traveling speed of the truck is not lower than the preset traveling speed of the truck by a preset value or more, it is determined that the traveling of the truck is not hindered, and the controller 51 The vehicle is driven in the two-wheel drive mode (step S6). That is, the truck is driven by the driving force of only the driving wheels of the traveling unit 2 provided behind the truck.

On the other hand, if it is determined in step S5 that the actual traveling speed of the truck is lower than the assumed traveling speed of the truck by a preset value or more, the controller 51
Causes the drive wheels of the traveling unit 2 for the four-wheel drive mode, which are provided in front of the bogie, to be lowered by the switching means (step S7). Next, in step S8, it is determined whether or not the drive wheels have descended by a predetermined distance and have come into contact with the road surface. If it is determined that the drive wheels have come into contact with the road surface, the traveling unit 2 for the four-wheel drive mode is operated. The drive wheel is driven by operating the drive motor. The operation control as described above is repeatedly performed while the vehicle is traveling.

As described above, according to the automatic guided vehicle of this embodiment, the traveling unit 2 is provided on the lower surface side in front of and behind the vehicle.
Are arranged respectively, the driving wheel rotation speed is detected by the tachogenerator 32, the traveling speed of the trolley is detected by the vehicle speed sensor 9, and the vehicle is driven based on the determination as to whether the traveling speed of the trolley corresponds to the driving wheel rotation speed. Since the occurrence of wheel slip is detected and the switching between four-wheel drive mode and two-wheel drive mode is controlled, the drive wheels for four-wheel drive are applied to the road surface only when necessary depending on the driving situation. It is possible to set the four-wheel drive mode in contact with each other to ensure stable traveling, and at the time of normal operation, steady traveling can be performed in the two-wheel drive mode, so that power consumption can be reduced and economical traveling can be ensured.

Therefore, there is no need to bother with the battery replacement work and increase the battery capacity as in the conventional case. Further, since the drive wheel rotation speed is compared with the actual traveling speed of the trolley, it is possible to accurately detect the slip phenomenon and perform fine control. Further, since the drive wheels for four-wheel drive are brought into contact with the road surface only when necessary, wear of the drive wheels for four-wheel drive is reduced and durability is improved, and resistance during two-wheel drive mode or manual running is reduced. Can be reduced.

FIG. 8 is a perspective view showing the schematic construction of an automated guided vehicle according to another embodiment of the present invention, FIG. 9 is an enlarged view showing the towing connecting portion shown in FIG. 8, and FIG. 9 is a bottom view of the automatic guided vehicle shown in FIG. The same members as those in the above embodiment are designated by the same reference numerals, and the description thereof will be appropriately omitted hereinafter.

At the upper center portion of the handle 5 of the unmanned transporting carriage, there is provided a towing connecting portion 55 for pulling a towed object such as luggage or another truck. As shown in FIG. 9, the towing connecting portion 55 is attached to the handle 5 via a load cell 56 which is a towing load detecting portion so that the towing load detected by the load cell 56 is input to the controller 51. It is configured. FIG. 10 is a view showing another embodiment of the towing connecting portion, and thus,
It is also possible to directly attach the strain gauge 58 to the support shaft of the traction connecting portion 55 to measure the traction load. On the other hand, FIG.
As shown in FIG.
The driving force of No. 1 is decelerated by the speed reducers 33 and 43, and is transmitted to the pair of left and right driving wheels 35 and 45 via the clutches 61 to 64. Note that manual traveling is possible by disengaging all the clutches 61 to 64.

In this embodiment, based on the traction load detected by the load cell 56 input to the controller 51, the operation of the front wheel clutches 61 and 62 connected to the drive wheels 35 and 45 arranged in front of the truck is performed. By controlling, the driving force is transmitted or cut off. The controller 51 frees the front wheel clutches 61 and 62 and the rear wheel clutch 6 in order to normally run in the two-wheel drive mode during normal operation.
3, 64 is turned on, but when the towing load detected by the load cell 56 exceeds a preset reference value, the controller 51 causes the front wheel clutch 61,
62 is also turned on to transmit the driving force from the driving motors 31 and 41 to the driving wheels 35 and 45 arranged in front of the truck to set the four-wheel drive mode.

According to this embodiment, when a heavy object to be towed is towed or towed on an uphill road surface, the vehicle can be run in the four-wheel drive mode.
By preventing the slipping of the driving wheels in advance, stable and economical traveling becomes possible. Further, since switching control is performed by turning on / off the clutch, the response is excellent.

The embodiments described above are not intended to limit the present invention, and various modifications can be made. For example, the method of detecting the traveling state of the truck is not limited to the above-described embodiment, and for example, based on the change in the motor load of the drive motors 31 and 41 that drives the drive wheels 35 and 45 provided behind the truck. It is also possible to control switching between the four-wheel drive mode and the two-wheel drive mode. In this case, it is detected that the motor load has increased due to slippage or the like by measuring the voltage across the resistor connected in series with the motor, and switching control is performed. Even with this structure, the same stable and economical traveling as in the above embodiment can be performed.

A sensor (for example, an optical sensor or a proximity sensor) provided on the trolley in which objects to be detected (for example, aluminum tape) are previously installed at the start point and the end point of a road surface section such as a slope where slipping is likely to occur. It is also possible to set the four-wheel drive mode only for the road surface section by detecting the detected object with. Further, the four-wheel drive mode may be set at the time of starting or braking requiring a driving force, or at the time of cornering.

[0039]

As described above, according to the present invention, the following effects are obtained for each claim.

According to the first aspect of the present invention, the pair of drive wheels are arranged on the left and right sides of the front and the rear of the bogie, respectively.
By means of detecting means for detecting the traveling condition of the trolley, four-wheel drive mode in which the trolley is driven by the driving force of driving wheels arranged in front of and behind the trolley, and driving force of driving wheels arranged in front of or behind the trolley. Since it has the switching means for switching to the two-wheel drive mode in which the trolley travels, and the control means for controlling the switching means based on the detection value of the detection means, the four-wheeled vehicle is only required when it is necessary according to the traveling situation. The drive wheels for driving can be brought into contact with the road surface to set the four-wheel drive mode to ensure stable running, and at the time of normal operation, steady running in the two-wheel drive mode can reduce power consumption. It is possible to secure proper running. Therefore, there is no need to bother with the battery replacement work and increase the battery capacity as in the conventional case.

According to the second aspect of the present invention, the detecting means has the drive wheel rotational speed detecting section for detecting the rotational speed of the drive wheel and the vehicle speed detecting section for detecting the traveling speed of the bogie. By comparing the rotational speed of the drive wheels with the actual traveling speed of the dolly, the slip phenomenon can be accurately detected and fine control can be performed.

According to the third aspect of the present invention, the detecting means is composed of a towing load detecting section which is connected to the carriage and detects the load applied by pulling the towed object. When pulling a towed object or pulling on an uphill road surface, it can be driven in four-wheel drive mode, and by preventing the drive wheels from slipping in advance, stable and economical driving Is possible.

According to the fourth aspect of the present invention, the switching means has the elevating mechanism portion for bringing the drive wheels into contact with or away from the road surface. Therefore, the drive wheels for four-wheel drive are used only when necessary. Can be brought into contact with the road surface, wear of the drive wheels for four-wheel drive can be reduced and durability can be improved, and resistance in the two-wheel drive mode or manual traveling can be reduced.

According to the fifth aspect of the invention, the switching means is constituted by a clutch for transmitting or cutting off the driving force interposed between the drive wheel and the drive section for driving the drive wheel. Switching control with excellent responsiveness can be performed by turning on and off.

[Brief description of drawings]

FIG. 1 is a side view showing a schematic configuration of an automated guided vehicle according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing the traveling unit shown in FIG.

FIG. 3 is a view of the traveling unit shown in FIG. 2 viewed from A.

FIG. 4 is a diagram showing how a drive wheel rotation speed is detected.

FIG. 5 is a view showing how the drive wheel rotation speed is detected by another embodiment.

FIG. 6 is a block diagram of switching control between a four-wheel drive mode and a two-wheel drive mode.

FIG. 7 is a flowchart of a switching operation between a four-wheel drive mode and a two-wheel drive mode.

FIG. 8 is a perspective view showing a schematic configuration of an automated guided vehicle according to another embodiment of the present invention.

FIG. 9 is an enlarged view showing the towing connecting portion shown in FIG. 8.

FIG. 10 is a view showing another embodiment of the towing connecting portion.

11 is a bottom view of the automated guided vehicle shown in FIG. 8. FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base plate, 2 ... Traveling unit, 5 ... Steering wheel, 6 ... Control panel, 7 ... Battery, 9 ... Vehicle speed sensor (vehicle speed detection part, a part of detection means), 12 ... Oscillating member (a part of switching means) ), 12a ... Engaging bracket (elevating mechanism part, part of switching means), 18 ... Elevating motor (elevating mechanism part, part of switching means), 19 ... Disc (elevating mechanism part, part of switching means) ), 20 ... Cam (elevating mechanism part, part of switching means), 27 ... Induction band, 31, 41 ... Drive motor (driving part), 32 ... Tacho generator (driving wheel rotation speed detecting part, one of detecting means) Part), 35, 45 ... Drive wheel, 51 ... Controller (control means), 52 ... Sensor (drive wheel rotation speed detection part, part of detection means), 56 ... Load cell (traction load detection part), 58 ... Strain gauge (Traction load detection unit), 61 to 64 ... Clutch ( Switching means).

Claims (5)

[Claims] 1. An unmanned transport vehicle that is driven by drive wheels and transports a load while detecting a guide zone on a road surface, wherein the drive wheels are arranged in a pair of left and right in front of and behind the truck, respectively. A four-wheel drive mode in which the vehicle is caused to travel by the driving means arranged in front of and behind the bogie and the driving force of driving wheels arranged in front of or behind the bogie is used to detect the traveling state. An unmanned guided vehicle comprising: a switching unit that switches to a two-wheel drive mode in which the vehicle travels, and a control unit that controls the switching unit based on a detection value of the detection unit. 2. The detection means includes a drive wheel rotation speed detection unit that detects a rotation speed of the drive wheel, and a vehicle speed detection unit that detects a traveling speed of the trolley. Unmanned guided vehicle as described. 3. The automated guided vehicle according to claim 1, wherein the detection means is a towing load detection unit that is connected to the truck to detect a load applied by pulling the towed object. . 4. The automatic guided vehicle according to claim 1, wherein the switching means includes an elevating mechanism section that abuts or separates the drive wheel from a road surface. 5. The clutch according to claim 1, wherein the switching means is a clutch for transmitting or cutting off a driving force interposed between the drive wheel and a drive section for driving the drive wheel. The unmanned carrier truck described in any of the above.