JP2023093267A - Work management system and method for managing work - Google Patents

Abstract

To prevent reduction of the productivity from happening due to doing a work again in a work management system.SOLUTION: A prediction error caused on a moving route between an accuracy reduction position and an accuracy returning position is calculated. If the prediction error is beyond an acceptable error, a reference station for receiving a correction signal is changed.SELECTED DRAWING: Figure 4

Description

The present invention relates to a work management system and a work management method.

A work machine that automatically performs a planned work requires a work management system for accurately performing the work. For example, in Patent Document 1, as an automatic traveling system that causes a work vehicle to follow a work route planned in a field, "a position information acquisition unit that acquires position information of the work vehicle by a satellite positioning system and a work in the work area. A route generation unit that generates a target travel route for automatically driving the vehicle, and an automatic travel control unit ( Summary excerpt)” is disclosed.

In addition, in a positioning system that measures the position of a moving target, a reference station (fixed station) placed at a known position uses radio waves received from artificial satellites to correct the position of the target to achieve high-precision positioning. There is a positioning method called RTK-GNSS (Real Time Kinematic-GNSS) that realizes measurement. In RTK-GNSS, it is known that the accuracy of the positioning target decreases as the baseline length, which is the distance between the positioning target and the reference station, increases.

For example, in Patent Document 2, as a positioning system that changes the reference station when the base line length increases and the positioning accuracy in RTK-GNSS decreases, "a server used for position measurement of a moving positioning target, and a plurality of different a reference station communication unit for receiving observation data generated by said reference station receiving radio waves from artificial satellites from a plurality of reference stations arranged at respective known position coordinates of said reference station; a correction information creation unit for creating positioning correction information used for position measurement of the positioning target based on the observation data; an information storage unit for storing the positioning correction information for each of the plurality of reference stations; a reference station selection unit that acquires approximate position information of a positioning target and selects one or more reference stations located near the positioning target based on the approximate position information of the positioning target; Based on the positioning target communication unit that receives from the positioning target the observation data received and generated by the positioning target, the positioning correction information of the selected one or more reference stations, and the observation data of the positioning target, A configuration including a position information calculation unit (summary excerpt) for calculating position information of a positioning target is disclosed. The operation of changing the reference station is generally called handover.

In addition, for positioning such as RTK-GNSS that directly calculates the position, there is a method of sequentially updating the position from related motion parameters such as velocity, attitude, acceleration, and angular velocity, which is called dead reckoning (for example, patent literature 3). In general, when RTK-GNSS results cannot be obtained, follow-up travel of the work machine is realized based on the position estimation results obtained by dead reckoning.

Japanese Patent Application Laid-Open No. 2021-22209 JP 2021-47054 A Japanese Patent Application Laid-Open No. 2019-179421 (Patent No. 06900341)

According to Patent Document 1, Patent Document 2, and Patent Document 3, when a work machine follows a planned work route and the baseline length increases and the positioning accuracy with RTK-GNSS decreases, handover is performed. A work management system that keeps track of the work machine based on the positioning results of dead reckoning is realized.

However, it is not necessarily the case that handover should be executed when positioning accuracy in RTK-GNSS is degraded. Positioning results using sensors such as dead reckoning have significantly lower positioning accuracy than RTK-GNSS.

In addition, since it is difficult to estimate the time required to execute a handover, if a handover were to be carried out for a long period of time, it is expected that the follow-up running of the work machine using dead reckoning would deviate greatly from the moving route. , it is assumed that productivity will decrease due to the occurrence of redoing of work.

SUMMARY OF THE INVENTION An object of the present invention is to prevent a decrease in productivity due to redoing work in a work management system.

A work management system according to one aspect of the present invention receives a satellite signal transmitted from a positioning satellite and correction information transmitted from a reference station, and automatically travels a work machine that performs work on a work site along a movement route. A management system, comprising: a positioning unit for positioning the work machine based on the satellite signal and the correction information; and a work plan storage unit for storing a work plan in which the movement route on the work site is described. a threshold determination unit for determining an allowable error between the movement path and the position of the work machine; and accuracy for detecting a position where the positioning accuracy of the work machine is reduced based on the positioning result of the positioning unit. an accuracy recovery position prediction unit that predicts an accuracy recovery position, which is a position at which the positioning accuracy of the working machine recovers, based on the movement path and the accuracy degradation position; and an accuracy recovery position and the accuracy recovery position. a reference station changing unit that calculates a prediction error occurring on the movement route between the accuracy recovery positions, and changes the reference station that receives the correction signal when the prediction error exceeds the allowable error. do.

ADVANTAGE OF THE INVENTION According to one aspect of the present invention, in a work management system, it is possible to prevent a decrease in productivity due to redoing work.

It is a figure which shows the hardware constitutions of a work management system. 3 is a block diagram showing the configuration of a road roller; FIG. FIG. 4 is a block diagram showing DR error data; It is a block diagram which shows the structure of a work management apparatus. It is a figure which shows an example of the work plan in the work site memorize|stored in the work-plan memory|storage part. FIG. 4 is a diagram showing variables for determining a movement route stored in a work plan storage unit; It is a figure which shows an example of the accuracy restoration position which the accuracy restoration position prediction part predicted. 9 is a flowchart showing processing of a reference station change unit; FIG. 11 is a diagram showing reference points generated on a movement path from an accuracy-reduced position to an accuracy-restored position; It is a figure which shows the definition of the amount of route deviations. It is a flow chart which shows processing of a work management system. It is a flow chart which shows processing of a work management device.

An embodiment of a work management system according to the present invention will be described below with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted. Moreover, the present invention is not limited to these drawings, and some components may not be used, and the components of each embodiment described below can be appropriately combined.

A work management system 1 according to this embodiment is a system that is mounted on a work machine, for example, and moves the work machine along a planned route in an unmanned operation state (in other words, automatic operation). Here, the work management system 1 of the present embodiment includes the road roller 2 because the work machine is a road roller. The working machine is not limited to a construction machine such as the road roller 2, but may be a working machine that moves along a planned route, such as an agricultural machine such as a tractor or a transport machine such as a forklift. It can be.

FIG. 1 is a diagram showing the hardware configuration of the work management system 1. As shown in FIG. A work management system 1 includes a road roller 2, a positioning satellite 4, a reference station 5, and a distribution server 9.

[Positioning satellite]
The positioning satellite 4 is an artificial satellite located above the earth, and constructs a GNSS (Global Navigation Satellite System) by transmitting satellite signals 516 (in other words, radio waves) to the earth. GNSS is a global navigation satellite system that receives satellite signals 516 from positioning satellites 4 and enables acquisition of its own position on the earth. The positioning satellites 4 are artificial satellites located above the earth.

[Reference station]
The reference station 5 is installed on the earth and receives satellite signals 516 transmitted by the positioning satellites 4 . The reference station 5 transmits satellite signals 516 received from the plurality of positioning satellites 4 to the distribution server 9 . A plurality of reference stations 5 are installed on the earth, and all the reference stations 5 transmit satellite signals 516 received from the positioning satellites 4 to the distribution server 9 . All the reference stations 5 have their positions on the earth determined in advance with high accuracy, and the position information is stored in the distribution server 9 .

[Distribution server]
Distribution server 9 generates correction signal 52 by receiving satellite signal 516 from reference station 5 . Correction signal 52 is generated for every reference station 5 that has transmitted satellite signal 516 to distribution server 9 . The correction signal 52 contains at least the satellite signal 516 received by the reference station 5 and the position of the reference station 5 on the earth.

The distribution server 9 is configured to be communicable with the road roller 2 . When the distribution server 9 receives the reference station selection position data 513 (described later) from the road roller 2, the distribution server 9 generates the correction signal 52 generated by the reference station 5 located closest to the position described in the reference station selection position data 513. It is transmitted to the road roller 2. In this embodiment, the reference station 5 receiving the correction signal 52 from the distribution server 9 may be referred to as a "connected reference station 5". The distribution server 9 receives the satellite signals 516 from all the reference stations 5 and distributes the correction signal 52 corresponding to the reference station selection position data 513, thereby omitting the process of determining the reference station 5 to be connected on the road roller 2 side. , the function of the satellite positioning device 25 is simplified.

[Road roller]
The road roller 2 to which the work management system 1 according to the present embodiment is applied is a known device for self-propelled compaction of the ground. It is a configuration comprising In the road roller 2, the front and rear rollers 21 and 22 are driven and steered by a traveling mechanism (not shown) such as a hydraulic circuit and an electric circuit built in the vehicle body 20, thereby rotating the rollers 21 and 22. This is a mechanism in which the road roller 2 moves forward and backward.

Two GNSS antennas 23 a and 23 b are arranged on the upper part of the vehicle body 20 to measure the position and orientation of the vehicle body 20 . The GNSS antennas 23a and 23b receive satellite signals 516 from a plurality of positioning satellites 4 located above the earth, and output the received satellite signals 516 to the satellite positioning device 25 (described later). The satellite positioning device 25 calculates the self-position (for example, latitude, longitude, altitude) of the road roller 2 on the earth based on the signals from the GNSS antennas 23a and 23b.

Although there are various types of satellite positioning methods using GNSS, this embodiment uses RTK-GNSS (Real Time Kinematic-GNSS) capable of acquiring the self-position with high accuracy. Details regarding RTK-GNSS will be described later. The road roller 2 is provided with a correction signal receiver 24, and the correction signal receiver 24 receives the correction signal 52 from the distribution server 9, thereby realizing acquisition of its own position using RTK-GNSS.

Further, the road roller 2 uses the correction signal receiver 24 to transmit the reference station selection position data 513 to the distribution server 9, thereby realizing acquisition of its own position using RTK-GNSS.

Moreover, if the arrangement positions of the GNSS antennas 23a and 23b on the vehicle body 20 are known in advance, the position of the vehicle body 20 on the earth can be obtained by calculating backward from the arrangement positions of the GNSS antennas 23a and 23b. Furthermore, since both the GNSS antennas 23a and 23b are mounted on the vehicle body 20, the orientation of the vehicle body 20 can also be obtained. In addition, in the following description, the GNSS antennas 23a and 23b may be collectively referred to as "GNSS antenna 23".

FIG. 2 is a block diagram showing the construction of the load roller 2. As shown in FIG.
As shown in FIG. 2, the road roller 2 includes a correction signal receiver 24, a satellite positioning device 25, a dead reckoning device 26, an operation command device 27, a vehicle body control device 28, a communication device 29, a dead reckoning error estimating device 35, and a work management device. 3. In addition, the road roller 2 includes a speed sensor 30, an attitude sensor 31, an acceleration sensor 32, an angle sensor 33, and a steering angle sensor 34 (hereinafter various sensors 36). The work management device 3 may be independent from the road roller 2 and arranged as a server in, for example, a management center. In that case, the work management device 3 is configured to be able to communicate with the road roller 2 .

[Satellite Positioning Device]
The satellite positioning device 25 calculates the self-position of the road roller 2 on the earth based on the GNSS antenna 23 and the communication device 29 (described later). The satellite positioning device 25 calculates a rough position on the earth (hereinafter, rough position data 50) and a precise position (hereinafter, precise position data 51).

The satellite positioning device 25 receives the satellite signal 516 from the positioning satellite 4 from the GNSS antenna 23 and the correction signal 52 transmitted from the distribution server 9 and received from the communication device 29 via the correction signal receiver 24, based on the approximate position data 50 and the Precise position data 51 is calculated.

The approximate position data 50 is the approximate position of the road roller 2 calculated by the satellite positioning device 25 using independent positioning. The precise position data 51 is the precise position of the road roller 2 calculated by the satellite positioning device 25 using RTK-GNSS. The precise position data 51 is a highly accurate positioning result that is closer to the actual position of the road roller 2 than the rough position data 50 is.

In the independent positioning, by obtaining carrier wave phases between at least four positioning satellites 4 and the road rollers 2 respectively, a pseudo-range between the positioning satellites 4 and the road rollers 2 is calculated, and the principle of triangulation is applied. , the approximate position data 50 is calculated. The carrier wave phase is obtained by observing the carrier wave phase when the positioning satellite 4 transmits a signal. The above-mentioned carrier wave phase includes the orbit of each positioning satellite 4, the accuracy of the clock used in the positioning device 25 and the positioning satellite 4, the delay of the carrier wave that occurs when passing through the ionosphere and troposphere, the bias included in the phase of the carrier wave, etc. Includes errors caused by

In RTK-GNSS, carrier wave phases between at least four positioning satellites 4 and road rollers 2 and carrier wave phases between at least four positioning satellites 4 and reference station 5 are obtained. Then, a carrier wave phase difference, which is the difference between the carrier wave phase between the positioning satellite 4 and the road roller 2 and the carrier wave phase between the positioning satellite 4 and the reference station 5, is calculated. In RTK-GNSS, when calculating the carrier wave phase difference, when the GNSS antenna 23 receives the satellite signal 516, it is known in the carrier wave phase of the satellite signal 516 which part of the continuous wave it is. The wavenumber integer part is unknown except for the wavenumber fractional part. In the RTK-GNSS, when this wave number integer part is determined, the baseline length between the reference station 5 and the road roller 2 can be obtained accurately.

Since the position of the reference station 5 on the earth is measured with high accuracy, the RTK-GNSS can predict the position of the road roller 2 from the base line length between the position of the reference station 5 and the road roller 2 . In the RTK-GNSS, the satellite positioning device 25 uses the position of the road roller 2 predicted from the position of the reference station 5 and the base line length between the road roller 2 to calculate the precise position data 51 by correcting the independent positioning result.

In the RTK-GNSS, when the baseline length between the reference station 5 and the road roller 2 is short, errors caused by the delay of the carrier wave that occurs when passing through the ionosphere and troposphere, the bias included in the phase of the carrier wave, etc. are canceled, and the reference station 5 and the base line length between the road rollers 2, the satellite positioning device 25 can determine the wave number integer part of the carrier wave phase difference and calculate the precise position data 51. FIG.

On the other hand, in RTK-GNSS, if the baseline length between the reference station 5 and the road roller 2 is long, the error caused by the delay of the carrier wave that occurs when passing through the ionosphere and troposphere, the bias included in the phase of the carrier wave, etc. cannot be canceled. Furthermore, since the satellite positioning device 25 cannot determine the wave number integer part of the carrier wave phase difference, the satellite positioning device 25 cannot calculate the precise position data 51 .

In the work management system 1, when the base line length between the reference station 5 and the road roller 2 becomes longer due to movement of the road roller 2, the satellite positioning device 25 may not be able to calculate the precise position data 51 in some cases. The work management system 1 determines that the precise position data 51 cannot be calculated when the satellite positioning device 25 cannot determine the wave number integer part of the carrier wave phase difference.

In the work management system 1, when the base line length between the reference station 5 and the road roller 2 becomes long and the positioning device 25 cannot calculate the precise position data 51, the satellite positioning device 25 can calculate the precise position data 51 by: A handover, which is a process of newly receiving the correction signal 52 from the reference station 5 with a short base line length instead of the connected reference station 5, is performed.

When the satellite positioning device 25 can obtain the wave number integer part using RTK-GNSS, the satellite positioning device 25 sends the precise position data 51 to the operation command device 27, the communication device 29, the work management device 3, and the dead reckoning error estimation device. Output. The satellite positioning device 25 outputs rough position data 50 to the communication device 29 and dead reckoning device when the wave number integer part cannot be obtained using the RTK-GNSS.

[Communication device]
The communication device 29 transmits the position information received from the work management device 3 and the satellite positioning device 25 to the distribution server 9 via the correction signal receiver 24 . When the communication device 29 receives the approximate position data 50 or the precise position data 51 as the position information from the satellite positioning device 25 , the communication device 29 transmits the data to the distribution server 9 as reference station selected position data 513 .

When receiving the reference station selection position data 513 from the work management device 3 , the communication device 29 transmits the data to the distribution server 9 . The distribution server 9 transmits the correction signal 52 according to the reference station selection position data 513 received from the communication device 29 . The communication device 29 transmits the correction signal 52 received from the distribution server 9 to the satellite positioning device 25 . When the correction signal 52 transmitted from the distribution server 9 cannot be received, the communication device 29 transmits a correction signal reception error 517 to the work management device 3 via the satellite positioning device 25 .

[Dead reckoning device]
The dead reckoning device 26 (hereinafter referred to as the DR device) receives as input a sensor that measures parameters indicating the momentum and attitude of the road roller 2, and generates DR relative position data, which is the amount of relative position and azimuth displacement of the road roller 2 at each time step. 53 is calculated. The DR device 26 calculates DR relative position data 53 based on various sensors 36 of the road roller 2 . Specifically, the DR device 26 may use a Kalman filter or the like for the values of the various sensors 36 to calculate the DR relative position data 53 that is the amount of relative position/azimuth displacement of the road roller 2 for each time step. When receiving the rough position data 50 from the satellite positioning device 25 , the DR device 26 also uses the rough position data 50 to calculate more accurate DR relative position data 53 . The DR device 26 outputs the calculated DR relative position data 53 to the dead reckoning error estimation device 35 , the work management device 3 and the motion command device 27 .

[Dead reckoning error estimator]
The dead reckoning error estimator 35 (hereinafter referred to as DR error estimator) estimates DR error data 58 that is the probability distribution of the DR occurrence error 514 based on the satellite positioning device 25 and the DR device 26 . The DR error estimating device 35 estimates the current position of the road roller 2 from the total value of the precise position data 51 acquired step t seconds before and the DR relative position data 53 from step t seconds to the present.

The DR error estimator 35 uses the latest precise position data 51 received from the satellite positioning device 25 as a true value, and calculates an error occurring in the current position of the road roller 2 estimated from the DR relative position data 53 as a DR generated error 514. do. The DR error estimation device 35 estimates DR error data 58 that is the probability distribution of the DR occurrence error 514 by calculating and recording the DR occurrence error 514 . The frequency of calculating the DR occurrence error 514 may be the same value as the control cycle, or may be a specific value such as 5 seconds or 10 seconds. If the vertical axis indicates the occurrence probability and the horizontal axis indicates the DR occurrence error 514, a graph such as that shown in FIG. 3 representing the DR error data 58 can be generated.

With reference to FIG. 3, it is possible to estimate at what value the DR occurrence error 514 is probabilistically generated. Since the DR error estimation device 35 calculates the DR occurrence error 514, the step t for recording the DR relative position data 53 may be the same value as the control period, or may be a specific value such as 5 seconds or 10 seconds. good. The DR error estimation device 35 outputs the calculated DR error data 58 to the work management device 3 .

[Operation command device]
The operation command device 27 issues an operation command to the vehicle body control device 28 based on the satellite positioning device 25 , the DR device 26 and the work management device 3 . The operation command device 27 has modes such as a normal running mode, a DR running mode, and a handover mode, and the work management device 3 selects each mode. The operation command device 27 issues an operation command to the vehicle body control device 28 according to the mode selected by the work management device 3 . The normal running mode, DR running mode, and handover mode will be described below.

[Normal driving mode]
In the normal travel mode, the road roller 2 follows and travels along a moving route 56 described in a work plan (described later) based on the precise position data 51 acquired from the satellite positioning device 25 . The road roller 2 follows the movement path 56 at the movement speed described in the work plan. The motion command device 27 determines the rotation speed and steering angle of the rollers 21 and 22 of the road roller 2 based on the work plan acquired from the work management device 3 and the precise position data 51 acquired from the satellite positioning device 25 .

The motion command device 27 determines the rotation speed/steering angle so that the road roller 2 moves on the movement path 56 . The motion command device 27 outputs the determined rotational speed and steering angle to the vehicle body control device 28 as control data 510 .

[DR driving mode]
In the case of the DR travel mode, the road roller 2 travels following the movement route 56 described in the work plan based on the DR relative position data 53 acquired from the DR device 26 . The road roller 2 follows the movement path 56 at the movement speed described in the work plan. Based on the movement route 56 described in the work plan acquired from the work management device 3, the precise position data 51 finally acquired from the satellite positioning device 25, and the DR relative position data 53 acquired from the DR device 26, the motion command device 27 Then, the rotation speed and steering angle of the rollers 21 and 22 of the road roller 2 are determined.

The motion command device 27 estimates the current position of the road roller 2 from the precise position data 51 and DR relative position data 53 last received from the satellite positioning device 25 . The motion command device 27 determines the rotation speed/steering angle so that the road roller 2 moves on the movement path 56 . The motion command device 27 outputs the determined rotational speed and steering angle to the vehicle body control device 28 as control data 510 .

[Handover mode]
In handover mode, the road roller 2 stops operating until the satellite positioning device 25 can calculate the precise position data 51 . The motion command device 27 stops calculating the rotational speed and steering angle, and commands the vehicle body control device 28 to stop the motion.

[Car body control device]
A vehicle body control device 28 controls the rollers 21 and 22 based on the motion command device 27 . The vehicle body control device 28 controls the rotational speed and steering angle of the rollers 21 based on the control data 510 acquired from the motion command device 27 . The vehicle body control device 28 controls the rollers 21 and 22 based on the control data 510 to operate the road roller 2 . The vehicle body control device 28 stops the operation of the road roller 2 when instructed to stop the operation by the operation command device 27 .

[Work management device]
FIG. 4 is a block diagram showing the configuration of the work management device 3. As shown in FIG.
The work management device 3 manages the operations of the motion command device 27 and the communication device 29 according to inputs from the satellite positioning device 25 , the DR device 26 and the DR error estimation device 35 . The work management device 3 includes a work plan storage unit 40 , an accuracy reduction position detection unit 41 , an accuracy recovery position prediction unit 42 , a reference station change unit 43 , a work command unit 44 and a threshold determination unit 45 .

[Work plan storage part]
The work plan storage unit 40 stores a work plan including work contents, work order, and movement speed to be performed by at least one road roller 2 . Since the road roller 2 is a working machine that self-propelled and compacts the ground, the content of the work of the road roller 2 in this embodiment is movement along the designated movement path 56 . The moving path 56 defines a moving direction in which the load roller 2 moves. The movement path 56 and movement direction of the load roller 2 are stored in the work plan storage unit 40 as a work order.

FIG. 5 is an example of a work plan for the work site 6 stored in the work plan storage unit 40. As shown in FIG.
The position of the road roller 2 on the work site 6 is defined by a site coordinate system (X, Y, Z). The horizontal direction on the work site 6 is represented by the X-axis and the Y-axis. The vertical direction on the work site 6 is represented by the Z-axis. FIG. 5 is a top view seen from the Z-axis direction in the field coordinate system. At work site 6 , the area to be compacted by road roller 2 is defined as passage area 8 . The work plan at the work site 6 describes the movement path 56 for compacting the passing area 8 by the rollers 21 and 22 of the load roller 2, the movement direction, and the movement speed. At the work site 6 , the area through which the rollers 21 and 22 have passed due to the road roller 2 moving on the movement path 56 is called a passed area 7 . The road roller 2 moves so that the center of the vehicle body overlaps the movement path 56 when viewed from the Z-axis direction in FIG.

In this embodiment, the work plan recorded in the work plan storage unit 40 includes that the road roller 2 reciprocates the passing area 8 in the Y-axis direction as shown in FIG. The travel path 56 and the travel direction of the load roller 2 for filling are described.

FIG. 6 shows variables that determine the travel route 56 stored in the work plan storage unit 40 .
As shown in FIG. 6, the movement route 56 of the work plan stored in the work plan storage unit 40 is defined by the vehicle width ω of the road roller 2, the interval width L of the movement route 56 in the X-axis direction of the work site 6, the overlap determined by the quantity α. The amount of overlap α is the X-axis component of the allowable error in the positional relationship between the load roller 2 and the moving path 56 . The overlap amount α is expressed by the following (Equation 1) using the interval width L of the moving path 56 and the vehicle width ω. The overlap amount α is an area in which the road roller 2 re-compacts the passed area 7 when the road roller 2 moves on the movement path 56 without causing a positioning error. The maximum positioning error in direction.

The vehicle width ω of the road roller 2 and the interval width L of the movement path 56 are stored in advance in the work plan storage unit 40 . The means for storing ω and L in the work plan storage unit 40 is not limited as long as the work plan in the work plan storage unit 40 can be edited.

[Precision drop position detector]
The reduced-accuracy position detection unit 41 detects a reduced-accuracy position 54 that is a position on the work site 6 where the positioning accuracy of the road roller 2 has deteriorated according to the input from the satellite positioning device 25 . The reduced-accuracy position detection unit 41 acquires the precise position data 51 from the satellite positioning device 25 . When the precision position data 51 cannot be acquired from the satellite positioning device 25, the precision position detection unit 41 determines that the positioning precision has decreased, and detects the position of the precision position data 51 received immediately before as the precision position 54. do. The accuracy reduction position detection unit 41 outputs the detected accuracy reduction position 54 to the accuracy restoration position prediction unit 42 and the reference station change unit 43 .

[Accuracy return position prediction unit]
An accuracy recovery position prediction unit 42 predicts a position on the work site 6 where the positioning accuracy of the road roller 2 is recovered to a good state based on the work plan storage unit 40, the accuracy reduction position detection unit 41, and the satellite positioning device 25. Predict position 55 .

FIG. 7 shows an example of the accuracy restoration position 55 predicted by the accuracy restoration position prediction section 42 . FIG. 7 is a top view seen from the Z-axis direction in the field coordinate system. The accuracy restoration position prediction unit 42 acquires the accuracy reduction position 54 from the accuracy reduction position detection unit 41 . Next, the accuracy recovery position prediction unit 42 acquires the position of the reference station 5 described in the correction signal 52 from the satellite positioning device 25 and calculates the distance LL between the accuracy reduction position 54 and the reference station 5 .

The accuracy return position prediction unit 42 assumes that the range LL around the reference station 5 is an observation range 57 in which the positioning device 25 can calculate the precise position data 51 . Then, the accuracy return position prediction unit 42 acquires the movement route 56 of the dump truck 2 from the work plan storage unit 40, the distance from the reference station 5 becomes LL again, and the movement route 56 becomes within the observation range 57 of the reference station 5 again. The position closest to the accuracy lowering position 54 is calculated as the accuracy restoring position 55 .

[Threshold determination unit]
Based on the work plan storage 40 and the accuracy recovery position prediction unit 42, the threshold value determination unit 45 sets an error threshold value 511 which is a positioning error allowed for the road roller 2 used for determining whether to change the reference station in the reference station change unit 43 (described later). to decide. The threshold determination unit 45 determines an allowable positioning error of the road roller 2 as the error threshold 511 at the accuracy restoration position 55 predicted by the accuracy restoration position prediction unit 42 . The threshold determination unit 45 calculates the overlap amount α using Equation 1 from the vehicle width ω of the road rollers 2 recorded in the work plan storage unit 40 and the gap width L of the movement path 56 . The threshold determining unit 45 sets the calculated overlap amount α as the error threshold 511 .

[Reference station change part]
Based on the work plan storage unit 40 , the accuracy recovery position prediction unit 42 and the DR error estimation device 35 , the reference station change unit 43 determines whether to change the reference station 5 that receives the correction signal 52 . Based on the DR error data 58 estimated by the DR error estimating device 35, the reference station changing unit 43 generates when the road roller 2 travels along the moving route 56 from the accuracy lowering position 54 to the accuracy restoring position 55 in the DR traveling mode. A DR prediction error ε[I] between the road roller 2 and the movement path 56 is estimated, and a change in the connected reference station 5 is determined.

The processing of the reference station changing unit 43 will be described below with reference to FIGS.

FIG. 8 is a flow chart showing the processing of the reference station changing unit 43. As shown in FIG.
In step S<b>101 , the moving route 56 of the road roller 2 is acquired from the work plan recorded in the work plan storage unit 40 . In step S102, the accuracy reduction position 54 detected by the accuracy reduction position detection unit 41 is acquired.

In step S103, the accuracy restoration position 55 predicted by the accuracy restoration position prediction unit 42 is obtained.
In step S104, a reference point 59 is generated on the movement path 56 from the accuracy reduction position 41 to the accuracy recovery position 42. FIG.

FIG. 9 shows reference points 59 generated on the movement path 56 from the accuracy reduction position 41 to the accuracy recovery position 42 . FIG. 9 is a top view seen from the Z-axis direction in the field coordinate system.

The reference point 59 is the position where the DR prediction error ε[I] is calculated in the next step S105. The reference point 59 may be generated based on the control cycle of the road roller 2, assuming that the road roller 2 moves along the movement path 56 at the movement speed described in the work plan based on the work plan storage unit 40. FIG. Also, the reference points 59 may be generated on the movement route 56 at the stored generation intervals by storing the generation intervals on the movement route 56 in advance in the reference station changing unit 43 . Also, let N be the number of generated reference points 59 .

Regarding the reference points 59 , the first reference point 59 is the accuracy reduction position 54 and the Nth reference point 59 is the accuracy recovery position 55 . The value of the DR prediction error ε(1) is zero at the position of reduced accuracy 54 . Also, the reference points 59 are numbered from 2 to N−1 in order from the position closest to the position of reduced accuracy 54 on the movement path 56 .

In step S105, the second reference point 59 is selected. In step S106, a DR prediction error ε[I] at the selected reference point 59 is calculated based on the DR error data 58 acquired from the DR error estimation device 35. FIG. Let I be the number of the selected reference point 59 . The reference station changing unit 43 predicts the route deviation amount 515 when the road roller 2 moves from the position of the (I−1)th reference point 59 to the Ith reference point 59 .

FIG. 10 shows the definition of route deviation amount 515 . FIG. 10 is a top view seen from the Z-axis direction in the field coordinate system.

The movement candidate points shown in FIG. 10 are positions that the road roller 2 may reach when it moves to the next reference point, and there are an infinite number of movement candidate points. As shown in FIG. 10, the route deviation amount 515 is defined as the orthogonal component distance with respect to the movement route 59 at the movement candidate point. It is assumed that the route deviation amount 515 stochastically occurs based on the probability distribution of the DR error data 58 .

The reference station changing unit 43 predicts the route deviation amount 515 from the error variance based on the DR error data 58 . The reference station changing unit 43 obtains the DR prediction error ε[I] from the maximum DR occurrence error 514 in the probability distribution of the DR error data 58 . Also, the DR prediction error ε[I] may be obtained using values in the 1σ, 2σ, and 3σ intervals of the probability distribution of the DR error data 58 .

In step S107, it is determined whether or not all the 2nd to Nth reference points 59 have been selected. If not, select the next reference point 59 and return to step S106. If all have been selected, the process proceeds to step S108.

In step S108, the DR total prediction error 512 predicted at the accuracy recovery position 55 is calculated by totaling the DR prediction errors ε[I] in the entire section from the 2nd to the N-th reference points 59. FIG.

In step S<b>109 , the error threshold value 511 permissible at the accuracy return position 55 acquired from the threshold determination unit 45 is acquired. In step S110, the DR total prediction error 512 is compared with the error threshold 511 obtained in step S109. If the DR total prediction error 512 is greater than or equal to the error threshold 511, the process proceeds to step S111. If the DR total prediction error 512 is less than the error threshold 511, go to step S112.

In step S111, the precise position data 51 last received from the satellite positioning device 25 is transmitted as reference station selected position data 513 to the work command unit 44. FIG. Then, the handover mode is instructed to the work command unit 44, and the process is terminated. In step S112, the position of the connected reference station 5 is transmitted as the reference station selection position data 513 to the work command unit 44. FIG. Then, the work instruction unit 44 is instructed to switch to the DR traveling mode, and the process is terminated.

[Work command department]
The work command unit 44 selects the mode of the operation command device 27 based on the work plan storage unit 40 , reference station change unit 43 , satellite positioning device 25 and DR device 26 . The work command unit 44 puts the operation command device 27 into the normal running mode when the accuracy-reduced position detection unit 41 does not detect the accuracy-reduced position 54 .

The work command unit 44 changes the operation command device 27 to DR running mode or handover mode based on the determination of the reference station change unit 43 . The work command unit 44 transmits the reference station selection position data 513 received from the reference station change unit 43 to the communication device 29 . When the DR travel mode is selected, the work command unit 44 uses the precise position data 51 and the DR relative position data 53 last received from the satellite positioning device 25 to predict the route deviation amount 515 shown in FIG.

When the route deviation amount 515 exceeds the error threshold value 511 determined by the threshold determination unit 45, the work command unit changes the operation command device 27 to the handover mode. When the work command unit 44 receives the correction signal reception error 517 from the communication device 29 via the satellite positioning device 25, it changes the operation command device 27 to the DR travel mode. When receiving the precise position data 51 from the positioning device 25, the work commanding unit 44 changes the operation commanding device 27 from the DR running mode to the normal running mode. When the positioning device 25 acquires the correction signal 52 from the communication device 29, the work commanding unit 44 changes the operation commanding device 27 from the handover mode to the normal running mode.

The processing of the work management system 1 will be described below with reference to FIGS. 11 and 12. FIG. FIG. 11 is a flow chart showing the processing of the work management system 1. As shown in FIG. FIG. 12 is a flow chart showing the processing of the work management device 3. As shown in FIG.

In step S201, the operation command device 25 is set to handover mode. In step S<b>202 , the satellite positioning device 25 receives satellite signals 516 from the positioning satellites 4 via the GNSS antenna 23 .

In step S203, it is determined whether the communication device 29 is connected to the distribution server 9 or not. If connected, proceed to step S206. If not connected, proceed to step S204.

In step S<b>204 , the satellite positioning device 25 performs independent positioning and calculates approximate position data 50 . In step S<b>205 , the communication device 29 receives the approximate position data 50 from the satellite positioning device 25 and determines the reference station selected position data 513 . In step S<b>206 , the communication device 29 transmits the reference station selection position data 513 to the distribution server 9 .

In step S<b>207 , it is determined whether the communication device 29 has received the correction signal 52 from the distribution server 9 . If so, the process proceeds to step S208. If not, the process proceeds to step S210. In step S<b>208 , the communication device 29 outputs the correction signal 52 received from the distribution server 9 to the satellite positioning device 25 .

In step S209, the satellite positioning device 25 uses the satellite signal 516 and the correction signal 52 to calculate the precise position data 51 by RTK-GNSS. In step S210, it is determined whether the operation command device 25 is in handover mode. If in handover mode, return to step S206. If the handover mode is not displayed, the process proceeds to step S211.

In step S<b>211 , the communication device 29 transmits a correction signal reception error 517 to the work command unit 44 . In step S212, the work command unit 44 determines whether the road rollers 2 have finished traveling on the movement route described in the work plan. When the running is finished, the process is finished. If not completed, the process proceeds to step S213.

In step S<b>213 , it is determined whether the work command unit 44 has received the precise position data 51 from the satellite positioning device 25 . If received, the process proceeds to step S214. If not, go to fine step S216. In step S214, the work command unit 44 changes the operation command device 27 to the normal running mode.

In step S<b>215 , the work command unit 44 outputs the work plan to the motion command device 27 based on the work plan storage unit 40 . In step S<b>216 , the accuracy reduction position detection unit 41 detects the accuracy reduction position 54 . In step S<b>217 , the threshold determination unit 45 determines the error threshold 511 based on the work plan storage unit 40 .

In step S<b>218 , the accuracy recovery position prediction unit 42 calculates the accuracy recovery position 55 based on the accuracy reduction position detection unit 41 , the work plan storage unit 40 and the satellite positioning device 25 . In step S<b>219 , the reference station change unit 43 determines whether to change the connected reference station 5 based on the accuracy reduction position detection unit 41 , the accuracy return position prediction unit 42 , the DR error estimation unit 35 , and the threshold determination unit 45 . When changing the connected reference station 5, the process proceeds to step S222. If the connected reference station 5 is not to be changed, the process proceeds to step S220.

In step S 220 , the position of the reference station 5 connected to the reference station changing unit 43 is set in the reference station selection position data 513 and transmitted to the communication device 29 . In step S221, the work command unit 44 changes the operation command device 27 to the DR travel mode. In step S<b>222 , the reference station changing unit 43 sets the precise position data 51 last received from the satellite positioning device 25 to the reference station selected position data 513 and transmits it to the communication device 29 .

At step S223, the work command unit 44 changes the operation command device 27 to the handover mode. In step S<b>224 , the DR device 26 calculates DR relative position data 53 . In step S225, it is determined whether the satellite positioning device 25 has successfully calculated the precise position data 51 or not. If successful, the process proceeds to step S226. If not successful, the process proceeds to step S227. In step S226, the DR error estimating device 35 calculates the DR error data 58 based on the satellite positioning device 25 and the DR device 26. FIG.

In step S227, the control data 510 is determined based on the mode in which the operation command device 27 has been selected. In step S<b>228 , the vehicle body control device 28 controls the road rollers 2 based on the control data 510 . In step S229, it is determined whether or not the reference station selection position data 513 received by the communication device 29 is the same as the position of the reference station 5 to which it is connected. If they are the same, go to step 230 . If they are not the same, the process returns to step S202.

In step S230, the work command unit 44 changes the operation command device 27 to the DR travel mode. In step S<b>231 , the work command unit 44 uses the precise position data 51 and the DR relative position data 53 last received from the satellite positioning device 25 to calculate the route deviation amount 515 . In step S<b>232 , it is determined whether or not the work command unit 44 has received the correction signal reception error 517 from the communication device 29 . If so, the process proceeds to step S234. If not, the process proceeds to step S233.

In step S233, the work command unit 44 determines whether the road roller 2 has reached the accuracy return position 55 or not. If reached, the process returns to step S214. If not, the process proceeds to step S234. In step S<b>234 , the work command unit 44 determines whether the route deviation amount 515 exceeds the error threshold 511 . If it exceeds, the process returns to step S222. If not, the process returns to step S215.

The work management device 3 of the present embodiment predicts the accuracy restoration position 55 when the accuracy reduction position 54 is detected. The work management device 3 then calculates a DR total prediction error 512 that occurs at the accuracy restoration position 55 when the road roller 2 travels along the movement route 6 from the accuracy reduction position 54 to the accuracy restoration position 55 in the DR travel mode. Finally, the work management device 3 determines a change in the connected reference station 5 based on the DR total prediction error 512 and the error threshold 511 .

In this way, even if the satellite positioning device 25 cannot calculate the precise position data 51 at the work site 6, it is confirmed that the load roller 2 can reach the accuracy recovery position 55, and the reference station changing unit 43 executes handover. can be determined, and it is possible to instruct the follow-up running of the work machine switched to dead reckoning, so that the operation of the road roller 2 can be continued in automatic operation and a decrease in productivity can be prevented.

As described above, in this embodiment, when a decrease in positioning accuracy is detected, the point where the positioning accuracy will recover is predicted, and if the work machine can reach the point by switching to dead reckoning, the work machine does not execute handover. If the work machine cannot reach the position, the work machine stops at the position where the positioning accuracy has deteriorated, and handover is executed.

In other words, when a decrease in positioning accuracy is detected in a work machine following a movement route, the point where the positioning accuracy is expected to recover is predicted, and the work machine follows the movement by switching to dead reckoning to that point. Based on the estimated error, it is determined whether the work machine can reach the point. If the work machine can travel to the point where the positioning accuracy is expected to be recovered, the work machine switched to dead reckoning is instructed to follow-up travel to the point. This prevents a decrease in productivity due to redoing work.

1 Work management system 2 Road roller 3 Work management device 25 Satellite positioning device 26 Dead reckoning device 27 Operation command device 28 Vehicle control device 29 Communication device 40 Work plan storage unit 41 Accuracy reduction position detection unit 42 Accuracy recovery position prediction unit 43 Reference station change Unit 44 Work command unit 45 Threshold determination unit 54 Accuracy drop position 55 Accuracy recovery position 513 Reference station selection position data

Claims (10)

A work management system that receives satellite signals transmitted from a positioning satellite and correction information transmitted from a reference station and automatically moves a work machine that performs work on a work site along a moving route,
a positioning unit that performs positioning of the work machine based on the satellite signal and the correction information;
a work plan storage unit that stores a work plan in which the movement route on the work site is described;
a threshold determination unit that determines an allowable error between the movement path and the position of the work machine;
a reduced-accuracy position detection unit that detects a reduced-accuracy position, which is a position where the positioning accuracy of the work machine has deteriorated, based on the positioning result of the positioning unit;
an accuracy recovery position prediction unit that predicts an accuracy recovery position, which is a position at which the positioning accuracy of the work machine recovers, based on the movement path and the accuracy reduction position;
a reference station changing unit that calculates a prediction error occurring on the movement route between the accuracy reduction position and the accuracy restoration position, and changes the reference station that receives the correction signal when the prediction error exceeds the allowable error; ,
A work management system characterized by comprising: a control command unit that commands control to the work machine based on the positioning result of the positioning unit and the work plan;
a vehicle body control unit that operates the work machine based on the command from the control command unit;
The reference station changing unit
determining a change in the reference station connected to the work machine based on the prediction error and the allowable error;
The control command unit is
2. Between the accuracy reduced position and the accuracy restored position, according to the determination result of the reference station selection unit, a command is issued to control the working machine so as to switch the traveling mode of the working machine. 3. The work management system according to . The reference station changing unit
calculating the prediction error that occurs at the accuracy restoration position when the working machine travels along the movement route from the accuracy reduction position to the accuracy restoration position;
determining whether the work machine can reach the accuracy return position based on the prediction error;
The control command unit is
If the result of the determination by the reference station selection unit is that the working machine can reach the accuracy restoration position, the working machine is instructed to travel to the accuracy restoration position, and the handover of the base station is not executed. to keep the work machine running,
If the work machine cannot reach the accuracy restoration position as a result of the judgment by the reference station selection unit, the work machine is stopped at the accuracy reduction position, and the handover of the base station is executed. The work management system according to claim 2. The work plan storage unit
storing a prohibited area for the work machine as the moving route on the work site;
The threshold determination unit
2. The work management system according to claim 1, wherein the allowable error is determined within a range in which the work machine does not enter the prohibited area of the work machine based on the work plan. The accuracy return position prediction unit is
2. The work management system according to claim 1, wherein a distance between said reference station and said position of reduced accuracy is calculated, and a position where said distance is reached again on said moving route on said work site is predicted as said position where said accuracy is restored. . The positioning unit
2. The work management system according to claim 1, wherein the correction information is received from the reference station closest to the position information based on the position information of the work machine acquired from a communication device. The reference station selection unit
7. The work management system according to claim 6, wherein when changing the reference station that receives the correction information, the position information of the work machine is input to the positioning section. The reference station selection unit
7. The work management system according to claim 6, wherein when the reference station that receives the correction information is not changed, position information different from the position information of the working machine is input to the positioning unit. The reference station selection unit
9. The work management system according to claim 8, wherein when the reference station that receives the correction information is not changed, position information of the reference station is input to the positioning unit as the position information different from that of the working machine. A work management method for receiving a satellite signal transmitted from a positioning satellite and correction information transmitted from a reference station to automatically travel a work machine that performs work on a work site along a movement route,
a positioning step of positioning the work machine based on the satellite signals and the correction information;
a work plan storage step of storing a work plan in which the movement route on the work site is described;
a threshold determination step of determining a tolerance in the movement path and the position of the work machine;
a reduced-accuracy position detection step of detecting a reduced-accuracy position, which is a position where the positioning accuracy of the work machine is reduced, based on the positioning result of the positioning unit;
an accuracy recovery position prediction step of predicting an accuracy recovery position, which is a position at which the positioning accuracy of the work machine recovers from the movement path, based on the movement path and the accuracy reduction position;
a reference station changing step of calculating a prediction error occurring on the movement route between the accuracy reduction position and the accuracy recovery position, and changing the reference station that receives the correction signal when the prediction error exceeds the allowable error; ,
A work management method characterized by having

Images