JPS6135482B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting the relative positional relationship between a hanging device of a crane, a suspended load, etc. and a target position on the ground side, and an apparatus used for carrying out the method.

Various technologies have been developed for automatic and unmanned operation of overhead traveling cranes, and it has become possible to control the stopping position in the traveling and traversing directions with considerable accuracy. Therefore, more accurate stopping position control is often required for targets on the ground.
In addition, in cases where the unloading position of a suspended load is not strictly specified and the approximate position is only fixed (such as when unloading onto a movable object such as a truck platform or trolley), it is necessary to specify the position in advance. Automatically stops at the specified position〓〓〓
After this, control is required to align the desired unloading position with the hanging tool and the hanging load. The following methods are known as means for detecting the relative positional relationship between the crane and the ground target position for performing such control. In other words, a target object on the ground is photographed using a television camera attached to a crane, and the relative position between the television camera and the target object is detected through image information processing. It requires specialized software, lacks versatility, and is expensive. In addition, lighting is often required for photographing, which is troublesome when put into practical use.

The present invention has been developed in view of the above circumstances, and is highly versatile, highly accurate, and capable of determining the relative positional relationship of a crane to a target not only in the horizontal direction but also in the vertical direction. The object of the present invention is to provide a method for detecting the position of a crane that does not require any special equipment, and a device used to carry out the method.

First, the principle of the present invention will be explained. In Fig. 1, a traversing trolley (not shown) of an overhead traveling crane is shown.
Above, a projector T and a receiver R are arranged in the transverse direction from the locus of the center of gravity of a hanging tool or a suspended load (not shown) (the vertical locus of the center of gravity of a suspended load, etc. that moves up and down when the wire is hoisted up or down). They are installed separated by D ₁ and D ₂ , respectively.
The projector T emits a narrow beam of light towards the ground and scans it in the transverse direction. This scanning area is a predetermined range, and this range includes objects that reflect the light beam more fully than other parts. As this object, that is, the position detection sign P, it is possible to use an existing object with a mirror surface, such as a rail, or a place where the reflection level changes suddenly, such as a step as described later, or by arranging a special mirror object. good. The reflected light from this sign P is then captured by a light receiver R, and the light receiving range of this light receiver R is made slightly wider than the scanning range of the projector T at the level where the mark P is located. . If the marker P is a movable object, it should be made slightly wider than the scanning range at the highest level in which it is likely to be located.
These scanning ranges, light receiving ranges, and furthermore, the lengths of the sign P in the traveling direction (the front and back directions of the drawing) may be appropriately determined depending on the accuracy of automatic stop control and the like.

The scanning means of the light projector T is attached with means for detecting the scanning direction, for example, means for detecting the scanning angle θ with respect to the limit of the scanning area on the side opposite to the light receiver R.

The light receiver R is capable of identifying at least the reflected light from the sign P and specifying the light receiving direction, and for example, the light receiving direction is specified as an angle φ based on the light receiving area limit on the opposite side from the projector T. It is. Then, the value of θ at the time when the light receiver R receives the reflected light from the marker P is detected from the scanning direction detection means, and the value of θ is detected from the light receiver R.
Find the value of φ from , give it to the arithmetic device, and calculate the horizontal separation x between the center of gravity locus L and the sign P, the projection, the receiver installation level, and the sign P using the following equations (1) and (2), respectively. Calculate the vertical separation distance y.

x=D ₁ tan (φ-φ ₁ )-D ₂ tan (θ-θ ₁
)/tan(φ− _φ1 )+tan(θ− _θ1 )…(1) y= _D1 + _D2 /tan(φ− _φ1 )+tan(θ−
θ ₁ )...(2) However, θ ₁ : Angle between the scanning area limit and the vertical line passing through the emitter T φ ₁ : Angle between the light receiving area source and the vertical line passing through the receiver R Note that (1) ), (2) is x=D ₁ −ytan(θ−θ ₁ ) y{tan(φ−φ ₁ )+tan(θ−θ ₁ )}=D ₁ +
It is calculated from the geometric relationship _D2 .

If the lateral stop position of the crane is readjusted based on x obtained in this manner, the stop position can be controlled. For example, when lowering a suspended load to a position where x = A, all you need to do is find the deviation between x and A determined by equation (1) and control the crane's traversal movement to eliminate this deviation.A small lateral movement is sufficient. so it is aligned correctly. Furthermore, if a sign P is attached to a suitable location on the loading platform of a truck, simply by positioning the loading platform at a position where this marker P falls within the light beam scanning area of the projector, the load can be unloaded at a predetermined position, for example, on the marker P. It will be done. In the latter case x=0
Of course, the traverse drive control should be performed so that the following is achieved.

On the other hand, regarding y, the crane's traverse level remains unchanged, and if the sign P is immobile, y is (2)
There is no need to calculate it as in the formula, just give it to the arithmetic unit as a known value, but if the mark P is installed on a movable object and its height position varies from time to time,
In other words, signs P are installed on the loading platforms of trucks of various sizes, and signs P are used to guide the gentle unloading of suspended loads.
When performing lowering control, this calculation of y is useful for the control.

Although it is possible to detect the position of the crane using the optical principle described above, if the suspended load is large or relatively close to the ground, the shadow will cause the crane to be far away from the target, that is, the sign P. The camera may fail to capture the reflected light, making it impossible to detect the position. Therefore, in the present invention, as shown in FIG. 2, two floodlights T ₁ and T ₂ are provided on the left and right sides of the hanging fixture, and two signs P ₁ and P ₂ are also provided in the same direction but at different positions.
To prevent position detection from becoming impossible due to blind spots caused by suspended loads. The receiver is the emitter T ₁ , T ₂ and the sign P ₁ ,
Two R ₁ and R ₂ may be provided corresponding to P ₂ , or one may be shared.

Furthermore, in the present invention, continuous light is projected and scanned in order to prevent the occurrence of blind spots due to scanning.

Next, the apparatus used to carry out the method of the present invention will be specifically explained based on the drawings. FIG. 3 is a schematic diagram of the device of the present invention, and for convenience of explanation, the light projecting device 1, the sign P
Although only one of each is shown, one projector 1 is provided on each side of the hook 95 as shown in FIGS. 2 and 3. Two signs P are also provided at different positions in the crane traverse direction.

A trolley 93 is attached to the main girder 92 of a crane 90 that runs on a runway 91 so as to be able to move horizontally, and a hook 95 wound around a hoisting drum is moored to carry a suspended load 96. It is designed to be able to go up and down. A light projecting device 1 and a light receiving device 2 are attached to this trolley 93 at a predetermined distance apart. The light projecting device 1 and the light receiving device 2 do not necessarily need to be installed at the same height, nor do they need to be installed at the same position in the traveling direction (front and back directions in the drawing). These differences can be dealt with in the arithmetic processing process for geometrically determining x and y in equations (1) and (2) above. For convenience of explanation, it is assumed here that the light projecting device 1 and the light receiving device 2 have different mounting positions only in the transverse direction.

FIG. 4 is a front view of the light projector 1, and FIG. 5 is a bottom view thereof. The projector 1 includes a light beam generator 10 using a laser beam generator, a rotating mirror 11 as a light beam scanner, and the like. That is, a light beam generator 10 is mounted outside one end of the housing 12 with the beam head facing the other end of the housing, and a plane mirror 11b is mounted on a horizontal shaft 11a rotatably provided in the housing 12 in the beam traveling direction. A rotating mirror 11 is disposed, and the front end of the horizontal shaft 11a extends through the housing 12, and a rod-shaped cam follower 13 is fixed to this end. A motor 14 is installed inside the housing at a position outside the light beam passage area, and its output shaft protrudes toward the front side of the housing. A narrow plate-shaped reference plate 16 is attached to each of the output shafts so as to rotate in conjunction with the output shaft. The cam 15 is mounted with a disk eccentrically mounted, and when the cam follower 13 in sliding contact with the cam follower 13 is pushed down to the lowest position as shown in FIG. It is reflected by the plane mirror 11b in the direction of the angle position θ ₁ from the vertical line passing through it to the side opposite to the light receiving device 2,
When the centrally symmetrical position rotates and comes in this state, the light beam is reflected in the direction of the scanning area limit (angle θ = θm from the scanning reference angular position) opposite to the scanning reference angular position. The reference plate 16 is positioned such that a predetermined signal can be obtained when the light beam is directed toward the scanning reference angular position. That is, a metal proximity switch (or a photo interrupter) 17 is provided in the rotation range of the reference plate 16, which can detect the passage of the reference plate 16, and detects, for example, the rising edge of the pulse signal of the switch 17 obtained by the passage of the reference plate 16. This is used as the detection standard for the beam projection scanning direction. The light receiving device 2 consists of a light receiving device 21 having a photoelectric conversion function and an optical system 22 for condensing light onto its element, and its light receiving range is from the light receiving range limit to φm (that is, φ=0 to φm). It is designed to cover a light projection scanning area corresponding to θ=0 to θm.

This light receiver 21 must be able to identify the reflection from the sign, that is, if the sign P has a sufficiently high reflectance compared to others as in this embodiment, the reflection at a level higher than a predetermined threshold level will be detected. If light is obtained, this is considered to be reflected light from the marker P, and if the marker P has a sufficiently low reflectance compared to others, the reflection is at a level lower than the predetermined threshold level. If light is obtained (including cases where reflected light is not detected), this is assumed to be reflected light from sign P. If a step is to be used as a sign, the level of reflected light can be determined by scanning the light. is drastically changing〓〓〓
It is necessary to be able to identify each sign by identifying it as a reflection from that sign. However, any type of identification may be possible depending on the form of the mark.

The light receiver 2 also needs to be able to detect the direction of light reception in combination with its optical system. The one-dimensional semiconductor position detector used in this example or the linear diode array is considered as a device that satisfies the above conditions, but image pickup tubes such as vidicon, or two-dimensional
A CCD array or the like may also be used.

A one-dimensional semiconductor position detector (for example, Hamamatsu TV S1352) outputs the position of a linearly moving light spot as an analog electrical signal.
The photoelectric wave is distributed to both electrodes according to the difference in distance between the electrodes at both ends of the element and the light spot.

FIG. 6 is a block diagram of the main parts of the electric circuit of the device of the present invention. The primary semiconductor position detector 21a constituting the light receiver 21 uses its current signal processing circuit 21b to detect a current I ₁ on one electrode side and a current I ₂ on the other electrode side.
Obtain the sum I ₁ + I ₂ and the difference _{I 1 − I 2 from} The data is supplied to the arithmetic unit 33 via the A/D converter 34 as data representing the spot position, in other words, the light receiving direction φ. On the other hand, I ₁ + I ₂
is input as a signal representing the amount of light received by this detector 21a to a binarization circuit 32 in which a predetermined threshold value is set, and the signal becomes high level only when an input exceeding the threshold value is received. This output is given to the counter 31 as a counting stop signal.

The counter 31 is connected to count clock pulses generated by the high frequency oscillator 30, and the output of the metal proximity switch 17 is applied to the counter 31 as a reset and counting start signal. These circuits may be connected to the housing 12, for example.
However, it is not necessary to install all of the components of the apparatus of the present invention in the crane, and a part of the electric signal processing circuit may be installed in the ground operator's room or the like.

FIGS. 7A to 7D are time charts for explaining the operation of the circuit shown in FIG. As shown in FIG. 7A, as the reference plate 16 rotates, a pulse signal _P17 is generated from the switch 17 once per rotation of the cam. FIG. 7B shows the I ₁ +I ₂ output of the light receiver 21. If a sign P with a sufficiently high reflectance compared to others is placed in the light projection scanning area on the ground,
The I ₁ + I ₂ output changes to show a peak when the reflection from the marker P takes place, and the light beam changes to the cam 1
5. Since the reference plate 16 makes one round trip between θ=θ and θm during one rotation, the above peak is a pulse signal.
It will appear twice during one cycle of P ₁₇ . By setting the threshold value of the binarization circuit 32 to an appropriate value in advance, the portion corresponding to the reflection from the marker P is extracted as a pulse signal P ₃₂ as shown in FIG. As a result, the counter 31 stops counting. Therefore, the counter 31 counts the time clock pulses from the rising edge of the pulse signal P ₁₇ to the rising edge of the pulse signal P ₃₂ as shown in FIG. This information will be read to the arithmetic unit 33 as information. Note that although the pulse signal P ₃₂ is emitted twice in one period of the pulse signal P ₁₇ , the second pulse, that is, the pulse when the beam moves backward, has no effect on the counting by the counter 31.

Then, the first pulse signal P ₃₂ is sent to the arithmetic unit 33.
is given as a timing signal for reading data to
While the aforementioned counter count value is read, the (I ₁ − I ₂ )/(I ₁ +I ₂ ) output of the photoreceiver 21 is sent to the A/D converter 3.
The data is read into the arithmetic unit 33 via 4. The former is θ
, and since _{the latter} is data representing φ, the arithmetic unit calculates the above ( _{1 )} , Calculate the horizontal separation distance x between the center of gravity locus L of the hanging tool 95 and the suspended load 96 and the sign P and the vertical separation distance y from the crane in equation (2). Then, the calculation result is given to the crane control circuit 34, and under the control thereof, the traversing motor etc. are driven to perform operations such as lowering the suspended load to a required position determined by the relative positional relationship between the sign P and the crane.

As shown in Fig. 2, the receivers R ₁ and R ₂ are
Needless to say, when a stand is provided, two circuits as shown in FIG. 6 are provided.

Next, the positions of the emitter, receiver, and sign will be explained.

The traveling direction of the crane, which is unrelated to the target on the ground,
Based on the stop position control in the transverse direction, the floodlight
The light emission scanning area of T ₁ (or T ₂ ) includes the marker P ₁ (or P ₂ ), and therefore the light receiving range of the receiver R ₁ (or R ₂ ) includes the marker P ₁ (or P ₂ ). Determine the relative position of each. Then, x and y are determined based on the data of the two light emitter/receiver sets, and each is averaged.
In addition, when the reflected light from one marker is not received, x and y are determined based only on the data of the other set. As mentioned above, depending on the situation, it is also possible to combine two projectors and one light receiver. In any case, when two projectors are used in this manner, the scanning periods of both are staggered and the scanning by both is correlated with each other.

FIG. 8 schematically shows a state in which the stepped portion of the bit is used as a mark. Only one of the floodlights is shown. In this case, the relationship between the angular position θ (=0 to θm) of light projection scanning by the light projector T and the light receiving direction angle φ (=0 to φm) is expressed as shown in FIG. That is, when θ = θ ₂ (where θ ₂ is the angle when the light beam is irradiating the bit edge (outside the pit) on the projector side), φ changes greatly, and when the light beam is irradiating the pit edge on the opposite side. When (θ=θ ₃ ~
θ ₄ ), the photoreceiver R cannot receive this. 10th
The figure is a graph showing the received light intensity of the photoreceiver R when there is such a change, and θ=θ
₂ , θ ₃ and θ ₄ , the received light intensity changes suddenly.
Therefore, by differentiating the signal corresponding to the received light intensity, the pit step can be used as a marker as described above. In other words, in this case, the fact that the amount of light reflected from the sign is weaker than the amount of light reflected from other parts and is zero is utilized. In this case, the light receiving direction may be detected based on the (I ₁ −I ₂ )/(I ₁ +I ₂ ) output of the light receiver immediately after the received light intensity suddenly changes.

As described above, the present invention is a method for determining the position of a marker by an optically simple method of one-dimensional projection and scanning of a light beam. Although it is possible to detect the position of the device, the device can be constructed at a low cost. Furthermore, since no special software is required for the arithmetic unit 33, and there are no special restrictions on the installation of ground-side signs, the system can be applied to any location.

Furthermore, even if the suspended load is large or located close to the ground, the presence of two floodlights and two signs makes it possible to detect the position by eliminating the effects of blind spots due to the suspended load. . Furthermore, since the continuous light is projected toward the sign, there is no inconvenience such as when the light is not reflected from the sign sometimes, which is the case when the light is projected intermittently.

The scanner that enables such continuous light projection is equipped with a rotational position detector of the cam 15 consisting of a reference plate 16, a metal proximity switch 17, etc., so that the scanning direction of the light projection can be accurately detected and the position detection accuracy can be improved. The present invention has excellent effects such as a high It goes without saying that the present invention can be applied not only to the detection of the position in the transverse direction but also to the detection of the position in the running direction.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the optical principle, FIG. 2 is an explanatory diagram of the method of the present invention, and FIG. 3 is a schematic diagram of the configuration of the apparatus of the present invention.
Fig. 4 is a front view of the projector, Fig. 5 is a bottom view, Fig. 6 is a block diagram of the main parts of the electric circuit of the device of the present invention, and Fig. 7 A to D are time charts for explaining its operation. , FIG. 8 is an explanatory diagram of the case where a stepped portion is used, FIG. 9 is a graph showing the relationship between θ and φ in that case, and FIG. 10 is a graph similarly showing the relationship between θ and the received light intensity. T, T ₁ , T ₂ ... Emitter, R, R ₁ , R ₂ ... Light receiver, 1 ... Light projector, 2 ... Light receiver, 10 ...
Light beam generator, 11... Rotating mirror, 14... Motor, 15... Cam, 16... Reference plate, 17... Metal proximity switch, 21... Light receiver, 31... Counter, 33... Arithmetic device . 〓〓〓

Claims (1)

[Scope of Claims] 1. One floodlight is provided on each side of the hanging device on the crane, and two signs are provided below the crane at different positions in the same direction as the floodlight; While continuously scanning a predetermined area including signs from top to bottom in a one-dimensional manner, the crane receives reflected light from the light projection scanning area, and when the reflected light that should be obtained from each sign is received. 1. A method for detecting a position of a crane, comprising: detecting a light emitting scanning direction and a light receiving direction; and determining the relative position of the crane with respect to each mark based on the detection results. 2 One light beam generator is installed on each side of the lifting device on the crane, and the light beams emitted by each beam generator are directed downward and within different ranges.
A scanner that performs continuous light projection scanning in a dimension, and a light receiver that is arranged to receive reflected light from a sign in the light projection scanning area of each light beam, and outputs an electrical signal according to the received light intensity and direction of light reception. and a light projection scanning direction detection means for a scanner, the scanner being interlocked with an eccentric disk cam, a cam follower in sliding contact with the cam follower, and reflecting a light beam emitted by a light beam generator. It has a mirror and a rotational position detector of an eccentric disk cam, and when the receiver receives reflected light of a predetermined intensity, it detects the object that emitted the reflected light based on the detection results of the light emitting scanning direction and the light receiving direction. A crane position detection device characterized by being configured to determine the relative position of the crane.