JPH0616245A - Travel position detecting device for yard machine - Google Patents

Abstract

PURPOSE:To detect the absolute positions of yard machines with high accuracy and reliability at low cost. CONSTITUTION:Optical fibers 20a-20d are laid at the side edge of a belt conveyors disposed at the travel paths of yard machines 4A-4D, and the yard machines 4A-4D are provided with heaters 25 for heating optical fibers 20a-20d locally to form specific temperature regions. The optical fibers 20a-20d and heaters 25 are covered with heat insulating means, and the optical fibers 20a-20d are connected to position detecting circuits 31A-31D. The position detecting circuit 31A-31D is provided with a wave divider 42 connected to each of the optical fibers 20a-20d, a semiconductor laser 43, a high speed averaging device 47, a distance computing device 48, a position computing processor 49, and the like so as to compute the distance from the delay time of Raman backward scattered light of laser pulses injected to the optical fibers 20a-20d, to compute temperature from the intensity ratio between the Stokes' light element and anti-Stokes' light element and to compute the distance of the specific temperature regions to obtain the absolute travel positions of the yard machines 4A-4D.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling position detecting device for a yard machine for detecting the traveling position of a raw material yard in a steel mill from a fixed point of the yard machine.

[0002]

2. Description of the Related Art In a raw material yard of a steel mill, for example, a large number of yard machines for carrying out three operations of traveling, turning and elevation in order to load and discharge powdered materials such as raw coal, ore and auxiliary raw materials. Is arranged so that it can travel on a rail laid on the ground, and the traveling position of each yard machine is detected in order to prevent collision between these yard machines.

As this traveling position detecting device, for example, Japanese Patent Application Laid-Open No. 56-108629 previously proposed by the present applicant has been proposed.
Publication (hereinafter, referred to as a first conventional example) and Japanese Patent Laid-Open No. 2-30
2602 (hereinafter referred to as a second conventional example). In the first conventional example, the rotation of the wheels is transmitted to the ground side through the synchro transceiver in response to the traveling of the yard machine, and the rotation is supplied to the pulse generating means to form a forward / reverse pulse signal according to the rotation. Together with the position measuring potentiometer that continuously generates the current position signal corresponding to the entire traveling length of the yard machine via the clutch, and the correction position signal is continuously output every time the reference position is started in synchronization with the position measuring potentiometer. Transmitted to the correction potentiometer that is generated, and the absolute position signal is generated by the absolute position signal detecting means each time the yard machine reaches a plurality of predetermined reference positions, and the positive position is generated according to the movement of the yard machine. The reverse pulse is counted by the reversible counter and the count value of the reversible counter is measured by the potentiometer for position measurement when the yard machine reaches the reference position. The position measurement potentiometer is preset by setting the absolute position correction value based on the current position signal, comparing the detected value of the correction potentiometer with the reference set value, and rotating both potentiometers so that the deviation becomes zero. It is configured to measure the accurate position of the yard machine by correcting the position detection deviation of.

The second conventional example is a mobile machine in which one end is fed through a capty cable wound on a reel, and a rubber optical cable in which both ends are taken out in the same direction with the capty cable folded back at approximately the center. It is constructed so that light is transmitted from one end to this optical cable, and the position of the mobile machine is detected from the change in the amount of light caused by winding or unwinding the captyre cable on a reel.

[0005]

However, in the first conventional example, the pulse signal, the current position signal and the corrected position signal are generated in synchronization with the rotation of the wheels or the like according to the traveling of the yard machine. Since the absolute position signal is generated every time the yard machine reaches the reference position and the error is corrected at the generation timing of the absolute position signal, the traveling position at the reference position can be accurately measured. But,
Since the position measurement is performed using the signal synchronized with the rotation of the wheel between the adjacent reference positions, the position measurement error due to the slip of the wheel, the friction loss in the rotation transmission path, etc. cannot be excluded, and the measuring device can be used. However, there is an unsolved problem that the configuration is complicated and the cost increases.

Further, in the second conventional example, the fact that the attenuation factor is different between the straight state of the optical cable and the curved state due to the captyre cable being wound on the reel is utilized to make the light incident from one end Since it is detected on the edge side and the position of the moving machine is measured from the amount of light attenuation,
Although it is not affected by wheel slip, the attenuation factor of the optical cable changes with temperature, and since the curvature factor of the optical cable changes with the reel winding diameter, the attenuation factor also changes. There is an unsolved problem that measurement cannot be performed.

In addition, a method for detecting the absolute position by installing a number of limit switches along the traveling path of the yard machine or using inductive radio has been proposed.
The method of installing a large number of limit switches has an unsolved problem that the equipment cost becomes enormous in the case of a long-distance yard and a lot of manpower is required for maintenance and maintenance of the equipment. The method has an unsolved problem that it becomes difficult to maintain accuracy due to subsidence of the road surface on which the yard machine travels.

Therefore, the present invention has been made in view of the unsolved problems of the above-mentioned conventional example, and a traveling position detecting device for a yard machine capable of accurately detecting the traveling position of the yard machine with a simple structure. Is intended to provide.

[0009]

In order to achieve the above object, a traveling position detecting device for a yard machine according to the present invention is a yard for transferring powder particles such as iron ores and coals to a conveyor for transport. In a traveling position detection device for a yard machine that detects the traveling position of a machine, an optical fiber is laid along the side of the conveyor in parallel with the traveling direction of the yard machine, and the optical fiber is locally attached to the yard machine. A temperature control means for heating or cooling to form a temperature singular region is installed, and a heat insulating means is formed so as to cover the optical fiber and the temperature control means, and a laser pulse is incident from one end of the optical fiber. By receiving the Raman scattered light in the temperature singular region of this laser pulse, by measuring the time from the incident time to the reception time of the Raman scattered light,
It is characterized by further comprising position detecting means for detecting a traveling position of the yard machine from a fixed point.

Here, when the position of the yard machine is detected, a calculation time is required from the emission of the laser pulse by the position detecting means to the position detection. Therefore, the yard machine continues for a preset time or longer. Therefore, it is desirable to perform absolute position calculation while stopped.

[0011]

According to the present invention, the optical fiber cable arranged along the side surface of the conveyor connected to the yard machine,
A temperature peculiar region is formed in the optical fiber by locally heating or cooling by the temperature control means arranged in the yard machine. In this state, a laser pulse is incident on the optical cable from the traveling position detection means, Raman scattered light by this laser pulse is measured, and the distance to the temperature singular region is measured,
Detects the absolute traveling position of the yard machine.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, and shows the overall arrangement of a raw material yard of a steel mill. In the figure, 1A to 1C are raw material yards formed at predetermined intervals, and raw material yards 1A to 1C are piled up with raw material particles 2a to 2g such as iron ore and coal.

Each of the raw material yards 1A to 1C is shown in FIG.
As shown in FIG.
3b and 3c, 3d are laid in parallel, and two yard machines 4A, 4B and 4C, 4 such as two reclaimers and stackers are provided on the traveling rails 3a, 3b and 3c, 3d, respectively.
D is arranged so that it can travel freely, and two belt conveyors 5a, 5b and 5c, 5 are provided in parallel between the traveling rails 3a and 3b and between 3c and 3d as shown in FIG.
d is provided.

As shown in FIG. 2, each of the yard machines 4A to 4D has a traveling carriage 6 which is guided by traveling rails 3a, 3b and 3c, 3d, and a swing which allows the traveling carriage 6 to turn. A cab 8 on which a trolley 7 is placed, and a cab 8 arranged at the top of the trolley 7, and a boom 9 having a boom conveyor (not shown) laid freely on the trolley 7
And a bucket wheel 10 mounted on the tip of the boom 9 for transferring the piled raw materials on the boom conveyor. Then, a cable 11 such as a power cable for receiving power supply from a controller on the ground and a control cable for interface of control signals is individually wound or rewound on the upper surface of the traveling carriage 6 as the yard machine moves. The cable reel 12 is equipped with a cable reel 12, and the power and various control signals from the cable 11 wound on the cable reel 12 are supplied to the onboard controller 13 arranged in the turning carriage 7.

Each of the belt conveyors 5a to 5d is composed of left and right vertical frames 15a and 15b, a horizontal frame 15c arranged at the upper ends thereof, and a conveyor belt 15d conveyed on the horizontal frame 15c. There is. Optical fibers 20a, 20c and 20b, 20d are laid on the left side surfaces of the belt conveyors 5a, 5c and the right side surfaces of the belt conveyors 5b, 5d, respectively.
Each of these optical fibers 20a to 20d is, as shown in FIG. 3, a horizontal frame 1 of the belt conveyors 5a and 5b.
The support 5 is attached to the left end side bottom surface portion and the right end side bottom surface portion of 5c. Also, the optical fibers 20a to 20
Guide rails 22a and 22b for restricting the height position from the horizontal frame 15c are disposed on both sides of d, respectively.

On the other hand, as shown in FIG. 3, a support piece 23 having an L-shaped cross section is attached to the lower end side lower surface of the yard machines 4A and 4C and the right end side lower surface of the yard machines 4B and 4D, respectively. An end is extended to a position facing the optical fibers 20a to 20d, a pantograph 24 is attached to a surface facing the optical fibers 20a to 20d, and an upper surface of the pantograph 24 is positioned at a position facing the optical fibers 20a to 20d. A heater 25 for heating as a control means is attached, and the guide rail 22a,
Guide rollers 26a and 26b which are in sliding contact with these are disposed at positions facing 22b.
The optical fibers 20a to 20d and the heating heater 2 are provided by the a and 26b slidingly contacting the guide rails 22a and 22b.
The distance from 5 is maintained at a constant value.

On the lower surface of the horizontal frame 15c of the belt conveyors 5a-5d, the optical fibers 20a, 20b,
A heat insulating cover 27 is attached so as to cover the guide rails 22a and 22b, the pantograph 24, and the heater 25 for heating. The heat insulating cover 27 has a through hole 27a through which the support piece 23 is inserted in the central portion of the lower plate. A flexible seal plate 28 formed of a heat-resistant rubber plate or the like that allows the support piece 23 to move is disposed in the through hole 27a. Here, the heating heater 25 is controlled by the onboard controller 13 of the yard machines 4A to 4D to stop the supply of electric power, and heats the optical fibers 20a to 20d to a temperature higher by about 10 ° C. than the maximum temperature of the outside air during heating. To form a temperature peculiar region.

Further, one ends of the respective optical fibers 20a to 20d are connected to a control center 29 arranged on the ground as shown in FIG. In the control center 29, as shown in FIG. 4, automatic control devices 30A to 30D that individually automatically control the yard machines 4A to 4D, and a stop signal S _S from these automatic control devices 30A to 30D are provided. The position detection circuits 31A to 31D as position detection means to which the one ends of the optical fibers 20a to 20d are connected and the position information P _I detected by these position detection circuits 31A to 31D are supplied.
And position correction control circuits 32A to 32D for correcting the current values of the automatic control devices 30A to 30D.

Each of the automatic control devices 30A to 30D is connected to the onboard control device 13 of each of the yard machines 4A to 4D via a cable 11, and the yard machines 4A to 4D are connected to the onboard control device 13. Various control signals for performing 4D traveling control, turning angle of the boom 9, elevation angle, drive control of the bucket wheel 10, energization control of the heater 25 for heating, etc. are transmitted, and the control result from the on-board controller 13 is sent. And position detection control circuits 32A to 3 that receive various detection signals
When absolute position information indicating the current position is input from 2D,
When the current position is corrected according to the absolute position information and then the movement control of the yard machines 4A to 4D is performed, for example, the relative position based on the count value obtained by counting the pulse signals from the encoders provided on the traveling wheels of the yard machines 4A to 4D. Is calculated and the relative position is added to or subtracted from the absolute position to sequentially change the current position.

Each of the position detection circuits 31A to 31D is shown in FIG.
As shown in FIG. 4, one end of each of the optical fibers 20a to 20d is
Optical demultiplexer 42 to be connected to each other, and a predetermined optical demultiplexer 42
Pulsed semiconductor laser 43 for supplying laser pulse of width
And the oscillation of the laser pulse of this pulsed semiconductor laser 43
Output of optical pulse demultiplexer 42 and pulse drive circuit 44 for controlling
The Stokes light component of the Raman backscattered light connected to the side
The filter 45a to extract and the anti-Stokes light component
Filter 45b to be extracted and these filters 45a, 4
Avalanche for photoelectrically converting the light component extracted in 5b
The photodiodes 46a and 46b and their photoelectric outputs are
After D / D conversion, pulse drive signal of pulse drive circuit 44
Add to the memory corresponding to each delay time starting from
Store and add M times a predetermined number of times and then divide by M
High-speed averaging processor 47 for averaging, and this high-speed averaging
Of the Stokes light corresponding to each delay time of
Calculate the intensity ratio of the average value of the Stich Stokes light and
Distance that measures the temperature distribution and calculates the distance that represents the maximum value
The separation calculation device 48 and the pole calculated by the distance calculation device 48.
Absolute for the yard machines 4A-4D by averaging the distances that represent the maximum value
And a position calculation processing device 49 for calculating the traveling position.
Therefore, the position calculation processing device 49 uses the automatic control devices 30A to 3A.
Stopping signal S from 0D_SIs entered,
Stopped signal S _SWith the start of monitoring the duration of
Output a pulse transmission command to the pulse drive circuit 44,
Stopping signal S_SPosition calculation time with preset duration
When it is above, the calculated absolute position information P_IReposition
It is sent to the positive control circuits 32A to 32D.

Next, the operation of the above embodiment will be described. The automatic control devices 30A to 30D exchange various control information, detection signals, and the like with the on-board control device 13 of each of the yard machines 4A to 4D to control traveling of each of the yard machines 4A to 4D and boom 9. The overall control of the stowage or delivery of raw materials is carried out. In this control state, one of the automatic control devices 3
When the traveling of the yard machines 4A to 4D is stopped at 0A to 30D, the corresponding automatic control device 30i (i = A
To D), the on-board controller 13 of the corresponding yard machine 4i
To the traveling stop command and the stop signal S
_S is sent to the position detection circuit 31i.

Therefore, in the on-board controller 13 of the yard machine 4i, the drive wheels of the traveling carriage 6 are stopped and the heater 25 for heating is energized, and the position detection circuit 31 is started.
In i, a pulse transmission command is transmitted from the position calculation processing device 49 to the pulse drive circuit 44 after a predetermined time sufficient for the heating heater 25 to reach the set temperature, and a drive signal is output from the pulse drive circuit 44. 43 and the high speed averaging processor 47. Therefore, the pulsed semiconductor laser 43 generates a laser pulse having a predetermined width, for example, about 50 cm to 1 m, which passes through the demultiplexer 42 and is incident on the optical fiber 20j (j = a to d). By propagating, it reaches the position of the heater 25 for heating of the yard machine 4i.

As described above, when the laser pulse propagates in the optical fiber 20j, scattering occurs at each propagation position as shown in FIG. 5, and the backscattered light similarly passes through the optical fiber 20j. Return to the position detection circuit 31i. Here, in the backscattered light, in addition to Rayleigh scattered light (the same wavelength as the incident light) that is generated by elastically scattering the incident light by the lattice vibration of the glass forming the core of the optical fiber, it is also inelastic. Raman scattered light generated by being scattered by is included. As shown in FIG. 6, the Raman scattered light has two components, a Stokes light component having a longer wavelength than the incident light and an anti-Stokes light component having a shorter wavelength than the incident light, and its intensity is about 10 times that of the Rayleigh scattered light. It is extremely weak at around ^-3 . However, these intensity optical fibers are sensitive to temperature changes. The intensity ratio of the Stokes light component and the anti-Stokes light component is a function of temperature as shown in FIG. By using these two wavelengths, it is possible to remove the influence of the fluctuation of the light source and the disturbance applied to the optical fiber.

Therefore, in the position detection circuit 31i, the returned backscattered light is passed through the demultiplexer 42 to the filter 45a,
45 b, the Stokes light component and the anti-Stokes light component, which are the two components of the Raman backscattered light, are separated and extracted by these filters 45 a and 45 b, and the extracted Stokes light component and anti-Stokes light component are avalanche photodiodes 46 a and 46 b. Photoelectric conversion is performed, and these photoelectric conversion outputs are input to the high-speed averaging processing device 47. Therefore, the high-speed averaging device 47 A / D-converts the photoelectric conversion outputs of the Stokes light component and the anti-Stokes light component, and the digital value thereof is converted into the pulse drive circuit 44.
The drive signal from is added and stored in the storage area of the memory corresponding to each delay time from the time of input. And
After all the backscattered light from the optical fiber 20j has returned, a laser pulse is generated again from the pulse semiconductor laser 43, and this laser pulse is made incident on the optical fiber 20j, and the Stokes light component and anti-light of the Raman backscattered light are emitted in the same manner as above. The detection of the Stokes light component is repeated, and this is repeated many times (for example, several thousand times), and then the cumulative value of the Stokes light component and the anti-Stokes light component stored in each storage area at each delay time is repeated M times. Averaging is performed by dividing by. This averaging process is performed to prevent a measurement error because the Raman backscattered light is very weak.

In this way, when the average value of the Stokes light component and the anti-Stokes light component for each delay time is calculated, these are output to the distance calculation device 48, and this distance calculation device 48 calculates each delay time. The generation position x (= v · t / 2) of the backscattered light is calculated based on t and the propagation velocity (about 200 m / μs) v of the laser pulse in the optical fiber 20j, and the Stokes at each generation position x is calculated. Light component I _s
The temperature of each part of the optical fiber 20j is calculated from the intensity ratio I _a / I _{s of the} anti-Stokes light component I _a . For the calculation of this temperature, for example, a map shown in FIG. 7 which is created in advance based on experiments or calculations is stored in a memory, and the map is referred to based on the calculated intensity ratio I _a / I _s. Calculate the temperature.

The optical fiber 20 calculated in this way
The temperature information of each part of j is output to the position detection processing device 49, and the position of the position detection processing device 49 facing the heating heater 25 of the yard machine 4i of the optical fiber 20j becomes a temperature singular region showing a temperature maximum value. Since this temperature singular area represents the position of the yard machine 4i, the peak point (+ 10 ° C. with respect to the ambient temperature) is detected while comparing the temperature at each position with the ambient temperature and the fixed point The absolute position of the yard machine 4i is calculated by obtaining the absolute distance from (for example, a duplexer).

When the stop signal of the yard machine 4i input to the position calculation processing device 49 reaches a set time, for example, about 90 seconds required for distance calculation, the yard machine 4i calculated by the position calculation processing device 49. The absolute position information P _I of the current position P _P input from the automatic control device 30 i and the absolute position calculated by the position calculation processing device 49 are output to the position detection correction control circuit 32 _i. When the two do not match, the correction information P _A for correcting the absolute position calculated by the position calculation processing device 49 as the current position is sent to the automatic control device 30i to update the current position of the automatic control device 30i. To do.

On the other hand, when the stop time of the yard machine 4i is shorter than the set time, it is determined that an error occurs in the distance detection value due to the movement of the yard machine 4i in the calculation process, and the calculation of the absolute position is stopped. Position detection correction control circuit 3
The transmission of the absolute position information for 2i is stopped, and the updating process of the current position is stopped. After that, when the yard machine 4i is started to travel by the automatic control device 30i, the stop signal is not output to the position detection circuit 31i.
Stop the absolute position detection process in the position detection circuit 31i,
It will be in a standby state.

As described above, according to the above embodiment, the position detecting circuit 31i detects the absolute position of the yard machine 4i every time the yard machine 4i stops for a relatively short set time or longer. Since the absolute position of the machine 4i can be accurately detected and the optical fiber 20j and the heater 25 for heating are covered with the heat insulating cover 27 and the flexible sealing plate 28, they are affected by the change of the outside air temperature. In addition, since the heater 25 for heating is constantly maintained at a constant distance from the optical fibers 20a to 20d by the guide rails 22a and 22b, the pantograph 24, and the guide rollers 26a and 26b, it is also affected by ground subsidence or the like. Without this, the absolute positions of the yard machines 4A to 4D can be detected with high accuracy. Further, since it is only necessary to lay the optical fibers 20a to 20d, the heat insulating cover 27, etc., it is possible to reduce the equipment cost and reduce the manual work for maintenance and inspection of the equipment.

Although the position detecting circuits 31A to 31D have the structure of a distributed temperature sensor using Raman scattered light, the distance resolution, the response distance, and the measuring time are prioritized over the temperature resolution and the temperature accuracy due to the nature of the position detection. It is desirable to have the system configuration. In addition, in the said Example, although the case where the position detection of several yard machines 4A-4D was performed by each position detection circuit 31A-31D was demonstrated, it is not limited to this, and one position detection circuit is used. The position detection of each of the yard machines 4A to 4D may be performed by time division.

Further, in the above embodiment, the case where the yard machines 4A to 4D travel straight is described, but the position detection can be performed even when the yard machines 4A to 4D travel in a curve along the travel rail, and the yard machines 4A to 4D travel on the travel rail. Not limited to this, the position of any yard machine can be detected as long as the yard machine travels with the travel path regulated from a fixed point.

Further, in the above embodiment, the case where the heating heater 25 is applied as the temperature control means has been described, but the present invention is not limited to this, and other heat medium can be used, and further refrigeration. A refrigerant such as a device or a refrigerating device can also be applied, and the point is that it can be distinguished from other ambient temperatures as a maximum value or a minimum value when the temperature distribution is measured.

Further, in the above embodiment, the case where the pantograph 24 is used to keep the heater 25 for heating and the optical fibers 20a to 20d constant is described, but the present invention is not limited to this, and elastic pressing such as a spring is used. The body may be applied.

[0034]

As described above, according to the position detecting device for a yard machine according to the first aspect, an optical fiber is laid along the belt conveyor at the absolute position of the yard machine, and the optical fiber is attached to the yard machine. A temperature singular area is formed by the temperature control means provided, the optical fiber and the temperature control means are covered with a heat insulating means, and a laser pulse is incident on the optical fiber to generate Raman scattered light in the temperature singular area of the laser pulse. By receiving, by measuring the time from the time of incidence to the time of reception of Raman scattered light, the absolute position of the yard machine is detected, so the absolute travel position of the yard machine over a long distance can be obtained at low cost. In addition to being able to detect with high reliability and high accuracy, it is possible to reduce equipment costs and significantly reduce manual labor for equipment maintenance and inspection. Since the fiber and the temperature control means so that covered with a heat insulating means, there is an advantage that it is possible to perform accurate absolute position detection without being affected by the ambient temperature change.

Further, according to the position detecting device of the yard machine according to the second aspect, the absolute position of the yard machine is calculated when the yard machine is continuously stopped for the time required for the position calculation or more, and this is used. Since the position of the yard machine is corrected, the yard machine can be used as a backup device of the collision prevention device, and the remote unmanned operation of the yard machine can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a side view showing a yard machine to which the present invention can be applied.

FIG. 3 is an enlarged view of a main part of the present invention.

FIG. 4 is a block diagram showing a control circuit configuration.

FIG. 5 is an explanatory diagram showing a state where backscattered light is generated by a laser pulse.

FIG. 6 is a graph showing an example of spectroscopic measurement of scattered light.

FIG. 7 is a characteristic diagram showing the relationship between the intensity ratio of the Stokes light component and the anti-Stokes light component and the temperature.

[Explanation of symbols]

 1A-1C Raw material yard 4A-4C Yard machine 5a-5d Belt conveyor 13 On-board controller 20a-20d Optical fiber 22a, 22b Guide rail 24 Pantograph 25 Heating heater 26a, 26b Guide roller 27 Insulation cover 28 Flexible sealing plate 29 control center 30A-30D automatic control device 31A-31D position detection circuit 32A-32D position detection correction control circuit 42 demultiplexer 43 pulse semiconductor laser 45a, 45b filter 47 high-speed averaging processing device 48 distance calculation device 49 position calculation processing device

Claims (2)

[Claims] 1. A traveling position detection device for a yard machine that detects the traveling position of a yard machine that conveys and conveys powdered or granular material such as iron ore and coal to a conveyor. An optical fiber is laid parallel to the traveling direction of the yard machine, and temperature control means for locally heating or cooling the optical fiber to form a temperature singular region is installed in the yard machine, and the optical fiber and the temperature are set. A heat insulating means is formed so as to cover the control means, a laser pulse is further incident from one end of the optical fiber, and Raman scattered light in the temperature singular region of this laser pulse is received,
A traveling position detecting device for a yard machine, comprising position detecting means for detecting a traveling position of the yard machine from a fixed point by measuring a time from an incident time point to a Raman scattered light reception time point. 2. The position detecting means detects the position and corrects the position of the yard machine when the yard machine is stopped continuously for a time longer than the time required for the position calculation. Driving position detection device for yard expectations.