JPS61257899A - Guide-surface follow-up type unmanned dolly - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

TECHNICAL FIELD The present invention relates to an unmanned transportation vehicle that carries a load at the front of the vehicle body and is guided by side guide surfaces.

2. Description of the Related Art In recent years, unmanned forklifts and automated guided vehicles have been developed for the purpose of saving labor in on-site transportation vehicles such as forklift trucks (hereinafter referred to as forklifts).

One type of such unmanned transportation vehicle is one that is guided by lateral guide surfaces. In such a type, a distance detecting means for detecting the distance between the guide surface and the vehicle body is provided on the side of the vehicle body, and the vehicle is driven unmanned along parallel to the guide surface.

Problems to be Solved by the Invention However, when guided by the above-mentioned guide surface,
The distance between the load in front of the vehicle and the guide surface is usually small,
Furthermore, since the distance detection means is located behind the cargo, if the guide surface is at an angle, there is a risk that the cargo may come into contact with the guide surface before the distance detection means detects the distance to the guide surface. Ta.

Means for Solving the Problems In order to solve such problems, the present invention provides a structure that is located in the vicinity of the front corner of the cargo on the guide surface side and that connects the guide surface and the front corner of the cargo. A distance detecting means for detecting the distance between the two is provided, and a position changing means is provided for changing the position of the cargo relative to the guide surface so that the distance detected by the detecting means is approximately constant.

Effects of the Invention With this method, the distance between the front end corner of the load and the guide surface is immediately detected, and the position of the load with respect to the guide surface is controlled according to the detected value. Even if the front end corner of the load is attached to the guide surface, it can be prevented from coming into contact with the guide surface, and if you look at it from a different perspective, it is possible to run the automated guided vehicle along the angled guide surface. be.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 and FIG. 2 show an example in which the present invention is applied to a counterbalance type forklift.

In the figure, reference numeral 2 denotes a vehicle body, with the front wheels serving as driving wheels 4 and the rear wheels serving as steering wheels 6.

The vehicle body 2 is provided with a balance weight 8 at the rear and a head guard 10 above.

At the front of the vehicle body 2, cargo handling devices including a fork 12, an outer mast 14, and an inner mast 16 are provided.

The inner mast 16 is guided by the outer mast 14 in the vertical direction via rollers, and the inner mast 16 further guides the lift bracket 18. A finger bar 20 is attached to the lift bracket 18 via a side shift attachment 19, and a pair of forks 12 are attached to the finger bar 20. When the inner mast 16 is raised by the operation of the lift cylinder 22, the lift bracket 18 is raised by a chain (not shown). finger bar 2
0 and the fork 12 are raised together. The lower end of the outer mast 14 is attached to the vehicle body 2 so as to be rotatable about one axis, and the operation of the tilt cylinder 24 causes the cargo handling equipment including the outer mast 14 to be tilted forward or backward. In addition, the side shift cylinder 26
, the finger bar 20 and the fork 12
is side-shifted relative to the lift bracket 18 in the left-right direction of the vehicle body 2.

This forklift 28 can be operated manned by a driver, but it can also be operated unmanned by guiding it using a guide wall 30 as shown in FIG.

A guide wall 30 is provided near the steering wheel 6 on the side of the vehicle body 2.
A lateral displacement sensor 32 is attached to detect the distance and traveling posture of the vehicle body 2 with respect to the guide wall 30 by contacting the guide wall 30 . The lateral displacement sensor 32 includes a box 36 fixed to the vehicle body 2, as shown in FIG. 3, and an entry/exit member 38 is provided within the box 36. The entry/exit member 38 includes a longitudinal main body 40, crossbars 42 and 43 fixed at right angles to one end and the upper surface of the intermediate portion of the main body 40, respectively, and a slider fixed to the lower surface of the intermediate portion of the main body 40. 44, and the slider 44 is connected to the box 36.
The guide wall 30 is movably supported by a guide rail 45 fixed to the guide wall 30 in a direction perpendicular to a wall surface 46 (hereinafter referred to as the guide wall surface 46 because the wall surface 46 functions as a guide surface). This in/out member 38 is always urged toward the guide wall surface 46 by two springs 47, and the amount of in/out from the box 36 is detected by a linear potentiometer 48. A contact plate 52 having a U-shaped cross section is attached to the distal end of the main body 40 of the entry/exit member 38 so as to be rotatable around the axis of a vertical shaft 50 at an intermediate portion. The contact plate 52 is held in a neutral position, normally perpendicular to the body 40, by two symmetrically arranged springs 54. Both ends of the contact plate 52 are roundly curved in a direction away from the guide wall surface 46, and a roller 56 is rotatably attached to each curved surface at a position slightly exposed to the outside through a notch. Therefore, if there is an obstacle such as a convex part on the guide wall surface 46, the contact plate 52 rotates around the axis of the shaft 50 to help overcome the obstacle. The rotation angle of the contact plate 52 around the axis of the shaft 50 is detected by a rotary potentiometer 58 shown in FIG. 4 with the neutral position as a reference. Note that if a covering band (circling belt) made of a flexible material such as rubber is wrapped around each of the rollers 56, and the covering band rotates while contacting the guide wall surface 46, the contact between the guide wall surface 46 and the guide wall surface 46 can be improved. Rubbing is avoided and followability is improved.

On the other hand, as shown in FIGS. 1 and 2, a lateral displacement sensor 6o, which is structurally completely similar to the lateral displacement sensor 36, is attached to the guide wall 30 of the load W loaded on the fork 12.
It is provided so that it can be positioned above the front corner of the side. That is, as mentioned above, a bracket 62 that projects horizontally toward the guide wall 3o is fixed to the rudder guard 10, and two guide rails 64 and 66 are located on the bracket 62 at the upper side of the vehicle body 2 and extend in the front-rear direction. Support bars 68 and 70 are fixed in parallel to the guide rails 64 and 66 and extend parallel to each other toward the front, and are slidably fitted in the front-rear direction.
8,700 Box 3G for lateral displacement sensor 60 at the front end
The bottom part is fixed with a bolt (not shown). Therefore, the lateral displacement sensor 60 is connected to the guide rail 64 .
66 and support bars 68, 70, it is movable in the front-rear direction above the load W, and these support bars 68, 7Q and the like constitute support means together with the bracket 62. Note that each end of the movement of the lateral displacement sensor 60 in the longitudinal direction is defined by contact between stopper protrusions 72 and 74 fixed on the bracket 62 and a stopper piece 76 fixed on the support bar 70.

A sensor sending motor 78 is fixed to the bracket 62, and a fixed pinion 80 is attached to the output shaft of this motor 78.
is engaged with a rack 82 fixed to the support bar 68. Therefore, the lateral displacement sensor 60 is moved in the front-rear direction by driving the motor 78 functioning as a driving means in both forward and reverse directions. The lateral displacement sensor 60 is normally located at a standby position where the stopper piece 76 is in contact with the stopper protrusion 74, but is moved forward by the operation of the motor 78 and is moved to the front end of the cargo W on the guide wall 30 side. It is located above the corner.

At the bottom of the box 36 of the lateral displacement sensor 60, a load W is placed.
A reflective optical sensor 84 is provided as end position detection means for detecting the front end of the front end. This optical sensor 84 includes a light emitter and a light receiver, and during an ON state in which light emitted from the light emitter is reflected on the top surface of the cargo W (in this example, an aluminum box) and is received by the light receiver, the lateral displacement sensor 60 However, when the reflected light disappears and the OFF state is reached, the motor 78 stops driving and stops the lateral displacement sensor 60 from moving forward. The motor 78 is provided with a rotation speed detection sensor 86 that calculates its rotation speed, and based on the detected value of the rotation speed detection sensor 86, the distance from the standby position of the lateral displacement sensor 6o to the forward end position is detected. It has become so.

The lateral displacement sensor 60 as described above functions as a distance detecting means for detecting the distance between the guide wall surface 46 and the front end corner of the cargo W on the guide wall surface 46 side using the output of the linear potentiometer 48. The running attitude of the vehicle body 2 with respect to the guide wall surface 46 is detected based on the output difference between the lateral displacement sensor 32 and the linear potentiometer 48 provided on the side of the vehicle body 2, and the convexity on the guide wall surface 46 is detected based on the outputs of both rotary potentiometers 58. This is to accurately detect faulty parts such as parts.

In addition, in this example, the guide wall 3o is the lateral displacement sensor 3
2 and 60, respectively, and is installed on the platform with a lower strip and an upper strip that follow the movement trajectories of 2 and 60, respectively, but it may also be a single wall that is not divided as such, and the container can be When loading cargo W into the container, the side wall of the container functions as a guide wall surface.

Next, FIG. 5 shows a control circuit for controlling the unmanned running of the forklift 28 as described above.

In this figure, 120 is a microprocessor (CPU:
a central processing unit) and is connected to an I10 interface 124 along with a memory 122.

The I10 interface 124 includes the lateral displacement sensor 32.
and 60 linear potentiometers 48 and rotary potentiometers 58, as well as an optical sensor 84 for detecting the leading end of the load W. In addition to a rotation speed detection sensor 86 that detects the rotation speed of the sensor delivery motor 78, various sensors and switches necessary for driving the forklift 28 unmanned are connected.

The I10 interface 124 further includes a travel control circuit 1.
40. Steering control circuit 142. Brake control circuit 144. A cargo handling control circuit 146 and a lateral displacement sensor drive circuit 147 are connected, a drive motor 148 for driving the drive wheels 4 is connected to the travel control circuit 140, and a steering motor for steering the peeling wheel 6 is connected to the steering control circuit 142. 150 are connected. The brake control circuit 144 also brakes the motor shaft of the drive motor 148! A magnetic brake 152 is connected as well as an electromagnetic valve 156 that controls oil pressure to a hydraulic brake 154 that brakes each drive wheel 4 . The cargo handling control circuit 146 includes the lift cylinder 22. Tilt cylinder 24. A solenoid valve 158 that controls the supply of hydraulic pressure to the side shift cylinder 26 and the like is connected, and by controlling the operation of the solenoid valve 158, the cargo handling equipment 160 including the fork 12 and the lift bracket 18 is controlled. The operation will be controlled. Furthermore, the above-mentioned sensor sending motor 78 is connected to the lateral displacement sensor drive circuit 147.

In the forklift truck 28 configured as described above, the CPU 120 stores operating signals of various sensors and switches including the lateral displacement sensors 32, 60, etc., in the memory 1.
Processing according to a program stored in advance in 22,
Steering, acceleration/deceleration, stopping of the forklift 28, special standby,
Automatically control automatic transfer, etc.

Such a forklift 28 is suitably used, for example, when loading cargo sequentially from the platform into a container retrofitted to the platform. First, when the fork 12 is inserted into the fork insertion groove or the pallet of the load W and the load W is placed in a stable position on the fork 12', as is clear from the flowchart shown in FIG. It is detected by a detection means such as a switch, and in the subsequent step S2, the sensor sending motor 78 starts operating, and the lateral displacement sensor 6
0 is moved forward from the above-mentioned standby position. Then, in step S3, it is determined whether the optical sensor 84 is in the ON state, and while it is determined that the optical sensor 84 is in the ON state, the motor 78
However, when the optical sensor 84 reaches the tip of the cargo W and turns off, step S4 is executed and the drive of the motor 78 is stopped. As a result, the lateral displacement sensor 60 is positioned above the front end corner of the load W on the guide wall surface 46 side, and the rotation speed detection sensor 86 detects the rotation speed of the motor 78 during the movement process of the lateral displacement sensor 60. It is stored in memory 122.

After the lateral displacement sensor 60 is positioned above the front end corner of the load W as described above, step S5 is executed and the forklift 28 starts traveling.

Thereafter, the lateral displacement sensor 60, the lateral displacement sensor 32, and each contact plate 52 run unmanned while contacting the guide wall surface 46, and the detection signals of these lateral displacement sensors 60 and 32 are sent to the CPU 1 via the I10 interface 124.
20, the CPU 120 controls the steering control circuit 142 so that the vehicle body 2, the volume 4w, and the guide wall surface 46 are kept substantially constant, and the running attitude of the vehicle body 2 is parallel to the guide wall surface 46. unmanned guidance.

At this time, even if the guide wall 30 has a bent portion C as shown in FIG. 1, since the lateral displacement sensor 60 is located near the front corner of the cargo W, reaches the bent portion C of the guide wall 30, the distance between the front end corner of the cargo W and the guide wall surface 46 and the bent portion C
The angle of CP is immediately detected by the lateral displacement sensor 60.
Sent to U120. The CPU 120 calculates the lateral displacement sensor 6 based on the detected value of the lateral displacement sensor 60 and from the rotation speed of the motor 78 stored in the memory 122.
The amount of steering required to maintain the distance between the front end corner of the load W and the guide wall surface 4G at a predetermined value is determined according to the forward end position of 0, and the steering motor is controlled via the steering control circuit 142. 150 is activated. Therefore,
Despite the existence of the bent portion C, the load W and the guide wall surface 4
6 is avoided, damage to the cargo W is prevented, and problems such as the cargo shifting do not occur.

In particular, in this embodiment, the lateral displacement sensor 60 is the optical sensor 84.
Since the lateral displacement sensor 60 is sent forward from the standby position, the lateral displacement sensor 60 can always be positioned above the front corner of the cargo W even if the length of the cargo W in the front-rear direction changes. However, if the length of the load W in the longitudinal direction is constant for each load W, the lateral displacement sensor 6
It is possible for 0 to be fixed.

Further, in the embodiment, the steering control circuit 142,
Although the steering means including the steering motor 150 and the CPU 120 has been used as a position changing means for changing the position of the cargo W with respect to the guide wall surface 46, it is possible to operate the side shift cylinder 26 via the cargo handling control circuit 146. It is also possible to avoid contact between the cargo W and the guide wall surface 46, and to make these function as a position changing means together with the CPU 120.

Further, in the above embodiment, in addition to the lateral displacement sensor 60 located near the front corner of the cargo W, a lateral displacement sensor 32 was provided located on the side of the vehicle body 2. It is also possible to omit 32, or to provide both lateral displacement sensors 60 and 32 but omit their rotary potentiometer 58'.

Further, the distance detecting means such as the lateral displacement sensor 60 is not necessarily limited to a contact type that contacts the guide wall surface 46, but may also be a non-contact type such as an ultrasonic sensor.

Furthermore, the guide surface on which the forklift 28 is guided unmanned is not limited to a flat surface such as a wall surface. For example, when the forklift 28 is guided while being in contact with a guide rail having an arcuate cross section, etc.
A curved surface may be used as a guide surface.

Furthermore, although the present invention is suitably applied to an unmanned forklift, it can also be applied to other unmanned transport vehicles that are not equipped with a cargo handling device, as long as a load is placed on the front of the vehicle and the vehicle is guided unmanned. can be similarly applied.

Although not described in detail, it goes without saying that the present invention can be practiced with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a plan view schematically showing a forklift truck according to an embodiment of the present invention, and FIG. 2 is a side view thereof. Third
The figure is an enlarged sectional view showing a part of FIG.
FIG. 4 is a sectional view taken along the line -mV in FIG. 3. FIG. 5 is a block diagram schematically showing a control circuit for the forklift shown in FIG. 1, etc., and FIG. 6 is a flowchart showing a part of the control program for the forklift. 2: Vehicle body 12: Fork 14: Outer mast 16: Inner mast 18: Lift bracket 20: Finger bar 30 Ni guide wall 32
: Lateral displacement sensor 48: Linear potentiometer 58 Two-rotation potentiometer 60: Lateral displacement sensor (distance detection means) 62 Nibble bracket 64, 66: Guide rail 68.
70: Support bar 78: Sensor delivery motor (drive device) 80: Pinion 82: Rank 84: Optical sensor (end position detection device) 86: Rotation speed detection sensor Applicant: Toyota Industries Corporation μ

Claims (3)

[Claims] (1) In an unmanned transportation vehicle that carries a load on the front of the vehicle body and is guided by a side guide surface, a vehicle is located near the front end corner of the load on the guide surface side, and is located between the guide surface and the load. Distance detecting means for detecting the distance between the load and the front end corner is provided, and position changing means is provided for changing the position of the cargo relative to the guide surface so that the distance detected by the detecting means is approximately constant. A guide surface following type unmanned transportation vehicle characterized by: (2) The unmanned transportation vehicle according to claim 1, wherein the position changing means is a steering means for steering the vehicle. (3) The unmanned transport vehicle has a fork in front of the vehicle body,
Further, the forklift truck includes a head guard above the vehicle body and supports a load with the fork, and the distance detecting means is supported so as to be movable in the front-rear direction by a support member extending forward from the head guard. and an end position detection device for detecting the front end of the cargo,
Claim 1 or 2, wherein the end position detection device is moved forward from a standby position by a drive device until the end position detection device detects the front end of the cargo, and is positioned above the front end corner of the cargo. The unmanned transportation vehicle described in paragraph 2.