Control system for work machine, work machine, and control method for work machine

A control system for a work machine includes a non-contact sensor, a position output device, a correction position calculation unit, and a control device. The non-contact sensor detects a periphery of a work machine. The position output device determines a position of the work machine based on at least a detection result of the non-contact sensor, and outputs information of the position. The correction position calculation unit corrects the position determined by the position output device based on delay time including at least a delay in communication with the position output device. The control device generates a command for controlling the work machine using the corrected position corrected by the correction position calculation unit.

FIELD

The present invention relates to a control system for a work machine controlled using positional information, a work machine, and a control method for a work machine.

BACKGROUND

There is a work machine such as a dump truck and an excavator in which various kinds of control are performed using a position acquired by a position of its own device acquired using a positioning satellite or a position of its own device acquired by, for example, dead reckoning navigation. In a system for position measuring using a global positioning system (GPS), a system that corrects a position measuring result in consideration with a radio wave is described in Patent Literature 1.

CITATION LIST

Patent Literature

Patent Literature 1: Japanese Patent Application Laid-open No. H11-183590 A

SUMMARY

Technical Problem

In a case where a control device that controls a work machine acquires a position of the work machine by communicating with another position measuring device provided in the work machine, delay in time for acquiring the position of the work machine possibly occurs due to delay caused by the communication between the devices, delay caused by instantaneous interruption of the communication between the devices, delay caused by a difference in control cycles between the devices, delay caused by processing in the position measuring device, and the like. When the timing for the control device to acquire the position of the work machine is delayed, accordingly, deviation occurs between reference time of which the position measuring device has determined the position of the work machine and the time of which the control device controls the work machine. As a result, delay in the control of the work machine possibly occurs.

The present invention has an object to suppress an influence of the delay caused when the control device controls the work machine in a case where the delay occurs in the timing of the control device to acquire the position of the work machine, due to at least one of the delay caused by the communication between the devices, the delay caused by instantaneous interruption of the communication between the devices, the delay caused by a difference in control cycles between the devices, the delay caused by processing in the position measuring device, and the like.

Solution to Problem

According to the present invention, a control system for a work machine, comprises: a non-contact sensor that detects a periphery of a work machine; a position output device that determines a position of the work machine based on at least a detection result of the non-contact sensor, and outputs information of the position; a correction position calculation unit that corrects the position determined by the position output device, based on delay time including at least a delay in communication with the position output device; and a control device that generates a command for controlling the work machine using a corrected position corrected by the correction position calculation unit.

It is preferable that the control device corrects the position using dead reckoning navigation.

It is preferable that the delay time is a difference between first time, which is time when the correction position calculation unit corrects the position, and second time, which is time before the first time and time when the non-contact sensor has performed the detection or when the position output device has received the detection result of the non-contact sensor.

It is preferable that the position output device determines the position of the work machine by receiving information for determining the position from the control device, the first time is time when the information for determining the position is output to the position output device by the control device, and the second time is time when the position determined by the position output device is corrected by the correction position calculation unit, and the delay time is the difference between the second time and the first time.

It is preferable that the control device, using the dead reckoning navigation, determines a position to which the work machine has moved, during the delay time, from the position having been received by the position output device and corresponding to the first time, and defines the determined position as the position after the correction.

According to the present invention, a work machine comprises: the control system for a work machine; and a traveling device controlled by the control device included in the control system for a work machine.

According to the present invention, a control method for a work machine, comprises: detecting a periphery of a work machine by a non-contact sensor; determining a position of the work machine based on a detected result, and outputting information of the position; and correcting, based on the output information of the position, the position by dead reckoning navigation using delay time including a delay caused when the information of the position has been received, and generating a command for controlling the work machine using the position after the correction.

The present invention can suppress an influence of the delay caused when the control device controls the work machine.

DESCRIPTION OF EMBODIMENTS

A mode (embodiment) for carrying out the present invention will be described in detail with reference to the drawings.

FIG. 1is a view illustrating an example of a site in which a working vehicle according to the embodiment is used. In the embodiment, the working vehicle is a mining machine used in a mine MR. In the embodiment, the mining machine is managed by a management system1. The management of the mining machine includes at least one of an operational management of the mining machine, the evaluation of the productivity of the mining machine, the evaluation of an operational technique of an operator who operates the mining machine, the maintenance of the mining machine, and the abnormality diagnosis of the mining machine.

The mining machine is a generic term for machines used in various work in the mine MR. The mining machine includes at least one of a boring machine, an excavating machine, a loading machine, a transporting machine, a crusher, and a vehicle in which a worker operates. The excavating machine is a machine that excavates the mine MR. The loading machine is a machine that loads a cargo onto the transporting machine. The loading machine includes at least one of an excavator, an electric shovel, and a wheel loader. The transporting machine is a machine that moves in the mine MR to transport the cargo. The transporting machine includes a dump truck. The cargo includes soil and/or ores generated by the mining operation in the mine MR.

The mine MR includes at least portions of a loading area LPA, a discharging area DPA, a conveying path HL, and an intersection IS. The conveying path HL leads to the loading area LPA and/or the discharging area DPA. The conveying paths HL intersect with each other at the intersection IS. There is a case where a crusher CR that crushes discharged soil is disposed in at least one of the discharging areas DPA. The mine MR includes a bank BK, which is formed with piled-up soil, along the conveying path HL. The bank BK may be provided at an outer side of the loading area LPA and/or an outer side of the discharging area DPA.

A dump truck2moves in the mine MR to transport the cargo. The dump truck2travels on at least the portions of the conveying path HL and the intersection IS in the mine MR to move between the loading area LPA and the discharging area DPA. The cargo is loaded onto the dump truck2at the loading area LPA. The loading area LPA is an area (place) at which the cargo is loaded in the mine MR. At the loading area LPA, a loading machine, which is another mining machine other than the dump truck2, loads the cargo onto the dump truck2.

The dump truck2unloads (discharges) the cargo at the discharging area DPA. The discharging area DPA is an area (place) at which the cargo is discharged in the mine MR. At the discharging area DPA provided with the crusher CR, the dump truck2discharges the soil, which is the cargo, into the crusher CR.

In the embodiment, the dump truck2autonomously travels on a traveling path RP by a command from a management device10, and is a so-called unmanned dump truck. When the dump truck2autonomously travels, an operation by an operator (driver) is unnecessary. The autonomous traveling of the dump truck2refers to traveling of the dump truck2by the command from the management device10, and not by the operation of the operator. In the embodiment, however, the dump truck2can travel by the operation of the operator.

The management system1is provided with the management device10and a communication system9. The management device10manages the mining machine operating in the mine MR. The communication system9transmits information. The management device10is installed in a control facility7of the mine MR. The communication system9transmits information among the management device10, the dump truck2, and another mining machine3(such as a hydraulic shovel3S and a vehicle3C) by wireless communication. The management device10, the dump truck2, and the other mining machine3are capable of interactive wireless communication via the communication system9. In the embodiment, the communication system9includes a plurality of repeaters6that relay signals (radio waves) between the management device10, the dump truck2, and the other mining machine3.

In the embodiment, a position of the dump truck2and a position of the other mining machine3are detected using a global navigation satellite system (GNSS). A GPS is an example of the global navigation satellite system; however, the GNSS is not limited to the GPS. The GNSS includes a plurality of positioning satellites5. The GNSS detects a position in a coordinate system that defines the latitude, the longitude, and the altitude. The coordinate system of the GNSS may be referred to as a global coordinate system in the embodiment. The position detected by the GNSS includes coordinate data of the latitude, the longitude, and the altitude.

The position of the dump truck2and the position of the other mining machine3in the mine MR are detected by the GNSS. The position detected by the GNSS is an absolute position defined in the global coordinate system. In the following description, the position detected by the GNSS is appropriately referred to as a GPS position. The GPS position is the absolute position, and the coordinate data (coordinate value) of the latitude, the longitude, and the altitude. In the GNSS, a state of a positioning changes depending on the arrangement of the positioning satellites5, ionosphere, troposphere, or the landform around antennas that receive information from the positioning satellites5. The state of the positioning includes, for example, a Fix solution (about ±1 cm to 2 cm from the precision), a Float solution (about ±10 cm to several meters from the precision), a Single solution (about ±several meters from the precision), and a non-positioning phase (impossible to calculate positioning).

As illustrated inFIG. 1, the management device10disposed in the control facility7is provided with a computer11, a display device16, an input device17, and a wireless communication device18. The computer11is provided with a processing device12, a storage device13, and an input/output unit15. The display device16, the input device17, and the wireless communication device18are connected to the computer11via the input/output unit15. The input/output unit15is used for inputting/outputting information between the processing device12and at least one of the display device16, the input device17, and the wireless communication device18.

FIG. 2is a schematic view illustrating the dump truck2that travels on the conveying path HL. The processing device12executes various types of processing relating to the management of the dump truck2and various types of processing relating to the management of the other mining machine3. When the dump truck2autonomously travels in the mine MR, the processing device12generates the traveling path RP on which the dump truck2travels. The traveling path RP is a set of a plurality of points PI. In other words, a track passing through the plurality of points PI is the traveling path RP. An absolute position (the coordinate data of the latitude, the longitude, and the altitude) is defined in each of the points PI. In each of the points PI that forms the traveling path RP, at least absolute positional information and speed information, which is a target speed of the dump truck traveling through such point, are included. Hereinafter, the absolute positional information and the speed information relating to the traveling path are collectively referred to as traveling path information. The dump truck2that has received the traveling path information from the processing device12travels along the traveling path RP that includes at least the portions of the loading area LPA, the discharging area DPA, the conveying path HL, and the intersection IS.

The storage device13is connected to the processing device12, and stores the various types of information relating to the management of the dump truck2and the other mining machine3. Moreover, the storage device13stores computer programs for causing the processing device12to execute the various types of processing. Using the computer programs stored in the storage device13, the processing device12performs the processing of information relating to the position, and generates the traveling path RP.

The display device16can display a map that includes the conveying path HL and the like in the mine MR, display information relating to the position of the dump truck2, and display information relating to the position of the other mining machine3. The input device17includes at least one of a keyboard, a touch panel, and a mouse. Moreover, the input device17functions as an operation unit that can input an operation signal to the processing device12. A manager of the control facility7operates the input device17to input a command to the processing device12.

The wireless communication device18includes an antenna18A, is disposed in the control facility7, and is connected to the processing device12via the input/output unit15. The wireless communication device18is a portion of the communication system9. Moreover, the wireless communication device18can receive information transmitted from the dump truck2and/or the other mining machine3. The information received at the wireless communication device18is output to the processing device12. In addition, the information received at the wireless communication device18is stored (registered) in the storage device13. The wireless communication device18can transmit information to the dump truck2and/or the other mining machine3. Next, the dump truck2will be described in detail.

FIG. 3is a diagram illustrating the dump truck2provided with a working vehicle control system30according to the embodiment. In the embodiment, an example in which the dump truck2is provided with the working vehicle control system30will be described. However, the working vehicle control system30may be provided in the other mining machine3which is a working vehicle other than the dump truck2. Hereinafter, the working vehicle control system30is appropriately referred to as a control system30.

The dump truck2includes a vehicle main body21, a vessel22, a traveling device23, and an obstacle sensor24. The vessel22and the traveling device23are mounted on the vehicle main body21. A driving device2D for driving the traveling device23is mounted on the vehicle main body21. The driving device2D includes an internal combustion engine2E such as a diesel engine, a generator2G, and an electric motor23M. The generator2G is driven by the internal combustion engine2E and generates electric power. The electric motor23M is driven by the electric power generated by the generator2G.

The traveling device23includes a front wheel23F, a rear wheel23R, a braking device23B, and a steering device2S. The front wheel23F is steered by the steering device2S, and functions as a steering wheel of the dump truck2. The rear wheel23R is driven by the electric motor23M disposed in a wheel, and functions as a driving wheel of the dump truck2. The driving device2D of the dump truck2may drive the rear wheel23R by transmitting motive power of the internal combustion engine2E to the rear wheel23R via a transmission including a torque converter.

The vessel22is a loading platform into which the cargo is loaded. The cargo is loaded into the vessel22by the loading machine. In discharging work, the vessel22is lifted to discharge the cargo.

The obstacle sensor24is arranged at a lower front portion of the vehicle main body21. The obstacle sensor24detects an obstacle in front of the vehicle main body21in a non-contact manner. In the embodiment, the obstacle sensor24, which is a non-contact sensor, is provided with a radar24A and a laser sensor24B.

The laser sensor24B is a device that detects a position of an object that exists around the dump truck2. The laser sensor24B applies a laser beam in a range illustrated inFIG. 2, for example, and receives the laser beam reflected by the object. In such way, the laser sensor24B detects a direction and distance of the object with respect to the laser sensor24B. The object around the dump truck2includes an object (such as the bank BK, a side wall, an embankment, a tree, and a building) that exists along the traveling path RP. The object that exists along the traveling path RP may be a structure produced artificially. Next, the control system30will be described.

The control system30includes a scan matching navigation position output controller33which is a position output device, and a vehicle body controller20which is a control device. In addition, the control system30includes the non-contact sensor24, a gyro sensor26, a speed sensor27, a GPS receiver31which is a positioning device, a traveling path creation device32, a wireless communication device34, a first signal line35, and a second signal line36. As illustrated inFIG. 3, the vehicle body controller20, the traveling path creation device32, and the scan matching navigation position output controller33are connected to the first signal line35. The vehicle body controller20, the traveling path creation device32, and the scan matching navigation position output controller33exchange information by communicating with one another via the first signal line35.

The vehicle body controller20receives the position of the dump truck2output from the scan matching navigation position output controller33and/or the GPS receiver31. Thereafter, the vehicle body controller20generates and outputs a command for controlling the dump truck2based on the received position of the dump truck2and traveling path information received from the traveling path creation device32described later. Moreover, the vehicle body controller20generates and outputs a command for controlling a braking device2B of the dump truck2using the received position of the dump truck2.

The traveling path creation device32acquires the traveling path information generated by the processing device12of the management device10illustrated inFIG. 1, and outputs the traveling path information to the vehicle body controller20. The traveling path creation device32is connected to the wireless communication device34connected to an antenna34A. The wireless communication device34receives information transmitted from the management device10and/or the mining machine3other than a corresponding vehicle. The mining machine3other than the corresponding vehicle includes a dump truck2other than the corresponding vehicle in addition to the other mining machine3other than the dump truck2.

FIG. 4is a diagram illustrating the vehicle body controller20according to the embodiment. The vehicle body controller20, which is a control unit, includes a processing unit20P, a storage unit20M, and an input/output unit20IF. The processing unit20P includes a correction position calculation unit20PA, a dead reckoning navigation position estimation unit20PB, and a traveling control unit20PC.

The correction position calculation unit20PA corrects the position of the dump truck2determined by the scan matching navigation position output controller33, which is a position output device, based on at least the delay time including a delay in communication with the scan matching navigation position output controller33. The dead reckoning navigation position estimation unit20PB calculates the position of the dump truck2using a method called dead reckoning navigation described later. Specifically, the dead reckoning position estimation unit20PB estimates the position of the dump truck2using an angular speed of the dump truck2from the gyro sensor26and speed of the dump truck2from the speed sensor27. The traveling control unit20PC generates the command for controlling the dump truck2using the corrected position corrected by the correction position calculation unit20PA.

The storage unit20M stores a computer program for causing the dump truck2to autonomously travel, and a computer program for controlling the operation of the dump truck2. The gyro sensor26, the speed sensor27, the steering device2S, a traveling control device2D, the first signal line35, and the second signal line36are connected to the input/output unit20IF. The input/output unit20IF is an interface between the vehicle body controller20and equipment connected to the vehicle body controller20.

The wireless communication device34receives the traveling path information transmitted from the wireless communication device18of the control facility7illustrated inFIG. 1, and outputs the received traveling path information to the traveling path creation device32. The GPS receiver31is connected to the wireless communication device34.

In the embodiment, the dump truck2travels in three traveling modes. A first traveling mode is a traveling mode in which the position of the dump truck is determined using detection data of the GPS receiver31, and the dump truck autonomously travels based on such position. The first traveling mode is appropriately referred to as a GPS traveling mode.

A second traveling mode is a traveling mode in which the position of the dump truck2is calculated using a method called scan matching navigation based on map information created in advance and detection data of the laser sensor24B, as described later, and the dump truck2autonomously travels based on the calculated position of the dump truck2. The second traveling mode is appropriately referred to as a scan matching navigation traveling mode. In addition, in the scan matching navigation traveling mode, the position of the dump truck2is calculated in the scan matching navigation position output controller calculation unit33.

Moreover, there is a method called dead reckoning navigation for estimating the position of the dump truck2using the detection result of the gyro sensor26and the detection result of the speed sensor27. The position of the dump truck2is estimated by the dead reckoning navigation in the vehicle body controller20.

The GPS receiver31detects the GPS position, which is the position of the dump truck2, using the GPS. The GPS receiver31is one of a plurality of positional information generation units included in the dump truck in the embodiment. An antenna31A that receives information from the positioning satellites5is connected to the GPS receiver31. The antenna31A outputs a signal based on the information received from the positioning satellites5to the GPS receiver31. In addition, the GPS receiver31detects a position of the antenna31A using the information from the positioning satellites5.

The scan matching navigation position output controller33determines the position of the dump truck2based on the information of the object that exists along the traveling path RP acquired from the detection result of the laser sensor24B, and based on the map information that includes the position of the object that exists in the mine MR in advance. The scan matching navigation position output controller33is one of the plurality of positional information generation units included in the dump truck in the embodiment. The map information is accumulated in a map database (DB)37.

In the embodiment, the vehicle body controller20, the traveling path creation device32, and the scan matching navigation position output controller33are implemented by a processor such as a central processing unit (CPU), and a memory. In such case, functions of the vehicle body controller20, the traveling path creation device32, and the scan matching navigation position output controller33are implemented when the processor reads and executes a computer program stored in the memory. The memory includes a nonvolatile or volatile semiconductor memory such as a random access memory (RAM), a read only memory (ROM), a flash memory, an erasable programmable read only memory (EPROM), and an electrically erasable programmable read only memory (EEPROM), a magnetic disk, a flexible disk, and a magnetic optical disk. The memory described above may be implemented by dedicated hardware, or the functions thereof may be implemented by the cooperation of a plurality of processing circuits.

The radar24A and the laser sensor24B are connected to the second signal line36. In addition to the second signal line36, the laser sensor24B is also connected to the scan matching navigation position output controller33. With the structure described above, the scan matching navigation position output controller33can directly receive a detection value of the laser sensor24B.

The vehicle body controller20acquires the detection values from the radar24A and the laser sensor24B via the second signal line36. The vehicle body controller20can determine a relative position between the dump truck2and the object using the detection values of the radar24A and the laser sensor24B. In other words, the relative position between the dump truck2and the object is detected when the radar24A and the laser sensor24B detect a position relative to the object.

The gyro sensor26detects an orientation or an orientation change amount of the dump truck2. The gyro sensor26is connected to the vehicle body controller20, and outputs a detection value, which is the detection result, to the vehicle body controller20. The speed sensor27detects a traveling speed, which is the speed of the dump truck2, by detecting a rotational speed of wheels of the dump truck2. The speed sensor27is connected to the vehicle body controller20, and outputs a detection value, which is the detection result, to the vehicle body controller20.

<Estimation of Position of Dump Truck2by Dead Reckoning Navigation>

In the embodiment, the vehicle body controller20estimates the position of the dump truck2using the dead reckoning navigation. The dead reckoning navigation is a navigation to estimate a current position of the dump truck2, which is a target, based on the orientation (orientation change amount) and a moving distance (speed) from the origin.

The orientation (orientation change amount) of the dump truck2is detected using the gyro sensor26included in the dump truck2. The moving distance (speed) of the dump truck2is detected using the speed sensor27included in the dump truck2. The vehicle body controller20determines the position of the dump truck2using the acquired orientation (orientation change amount) of the dump truck2and moving distance (speed) of the dump truck2.

<Calculation of Position of Dump Truck2by Scan Matching Navigation Position Output Controller33>

During the scan matching navigation traveling mode, the scan matching navigation position output controller33determines the position of the dump truck2using the detection value of the laser sensor24B and the map information of the mine MR created in advance. In other words, the scan matching navigation position output controller33calculates the position of the dump truck2by collating the detection result of the laser sensor24B and the map information.

In such case, the scan matching navigation position output controller33determines the position of the dump truck2using the detection value of the laser sensor24B and the map information, and outputs the determined position thereof to the first signal line35. The vehicle body controller20receives, via the first signal line35, the position of the dump truck2determined by the scan matching navigation position output controller33, and causes the dump truck2to travel along the traveling path RP.

The map information is information that includes a position of the object (such as the bank BK and the side wall) provided along the traveling path RP or the like in the mine MR. The map DB37that accumulates the map information is connected to the first signal line35. It is necessary to create the map information in advance before calculating the position of the dump truck by the scan matching navigation. For the creation of the map information, for example, the detection result of the laser sensor24B in the dump truck2traveling on the conveying path HL can be used. In a state where the position of the dump truck2is determined with high accuracy by the GPS receiver31, for example, the presence/absence and the position of the bank BK provided along the conveying path HL are detected by the laser sensor24B, and the presence/absence and positional data of the bank BK can be stored in the map information that corresponds to the conveying path HL.

FIG. 5is a diagram illustrating a portion of the map information in the embodiment. The portion of the map information inFIG. 5indicates the detection result of the bank BK from the radar sensor24B in an area around the conveying path HL. The conveying path HL is a blank area in a central portion that extends in an x-direction inFIG. 5. The bank BK is an area in which black and white are scattered in an upper portion and a lower portion inFIG. 5. As illustrated inFIGS. 5 and 6, in a plan view, the map information indicates a position of a grid GR in an XY-coordinate system where the mine MR is divided into predetermined sizes, and indicates whether the bank BK exists in each grid GR.

In the embodiment, among the grid GR in the map information, a grid DR1, which is a position in which the bank BK has been detected, is represented in a black square in the drawing, and a grid DR2, which is a position in which the bank BK has not been detected, is represented in a white square in the drawing. The map information stores the presence/absence of the bank BK, and the positional information. The map DB37that accumulates the map information is an external storage device (auxiliary storage device) that includes at least one of a ROM, a flash memory, and a hard disk drive.

FIG. 7is a schematic diagram illustrating an example of a partial area of the map information according to the embodiment.FIG. 8is a schematic diagram illustrating an example of the detection result of the bank BK by a laser sensor24B when the dump truck has traveled on the conveying path HL.FIG. 9is a schematic diagram illustrating a state in which the map information inFIG. 7is collated with the detection result of the laser sensor24B inFIG. 8in order to calculate a position of the corresponding vehicle by the scan matching navigation. InFIGS. 7 to 9, the grid DR1, which is the position in which the bank BK exists in the map information, is represented in dense parallel oblique lines. In addition, a grid DR3, which is a position in which the bank BK has been detected by the laser sensor24B, is represented in sparse oblique parallel lines.

Position calculation of the dump truck using the scan matching navigation illustrated inFIGS. 7 to 9is performed by the scan matching navigation position output controller33. In the position calculation of the position of the vehicle of the dump truck itself by the scan matching navigation position output controller33, the position of the dump truck close to the real position can be calculated while the calculation cost is suppressed by using a plurality of points (particles) PA virtually disposed within a range in which the dump truck is expected to exist at a certain point of time. In order to calculate the position of the corresponding vehicle by the scan matching navigation using the particles, the orientation (orientation change amount) and information of the moving distance (speed) of the corresponding vehicle at the point of time, that is, information relating to the dead reckoning navigation, are required. Position estimation by the scan matching navigation using the particles is a known technique; therefore, detailed description thereof is omitted.

The position calculation by the scan matching navigation collates the detection result of the non-contact sensor and the map information in each calculation cycle for each calculation using the particles. Therefore, it takes certain amount of time for the calculation. Consequently, a delay caused by the processing in the scan matching navigation position output controller33is large.

In the map information illustrated inFIG. 7, each square represents the grid GR. In addition, the colored grid DR1represents a grid in which the bank BK has been detected, and the white-colored grid DR2represents a grid in which the bank BK has not been detected.FIG. 8illustrates detection data DR3that the laser sensor24B of the dump truck has actually detected.

The map information illustrated inFIG. 7is collated with the detection result of the laser sensor24B illustrated inFIG. 8for position estimation using the particles. Using the method for the position estimation, there is calculated a final estimate value (expected value) Po of a position in which the probability of existence of the dump truck2is assumed to be the highest as illustrated inFIG. 9. The scan matching navigation position output controller33outputs a position at the most approximate as the positional information of the dump truck2. In the embodiment, the positional information of the dump truck2may include orientation information that indicates the orientation of the dump truck2.

In the scan matching navigation traveling mode, the vehicle body controller20acquires the position of the dump truck2output from the scan matching navigation position output controller33. Then, the vehicle body controller20controls the traveling of the dump truck2using the acquired information so that the dump truck2travels along the traveling path RP.

<Flow of Data During Scan Matching Navigation Traveling Mode>

In the embodiment, during the scan matching navigation traveling mode, the vehicle body controller20acquires the positional information of the dump truck2from the scan matching navigation position output controller33by communication. In addition, the scan matching navigation position output controller33receives, by communication, the detection result of the laser sensor24B, the map information, and the speed and the orientation change amount of the corresponding vehicle which are information required for calculating the position of the dump truck2by the scan matching navigation. Specifically, the scan matching navigation position output controller33acquires the detection result from the laser sensor24B, the map information from the map DB37, and the detection value of the gyro sensor26and the detection value of the speed sensor27from the vehicle body controller20.

The flow of data during the scan matching navigation traveling mode will be described in detail later. At first, the scan matching navigation position output controller33receives the detection values of the gyro sensor26and the speed sensor27from the vehicle body controller20, receives the detection result from the laser sensor24B, and receives the map information from the map DB37. The scan matching navigation position output controller33, then, calculates the position of the dump truck based on the scan matching navigation. Thereafter, the scan matching navigation position output controller33transmits a calculation result to the vehicle body controller20. Then, the vehicle body controller20controls the vehicle based on the received position of the dump truck2.

In the case of the present embodiment, the communication between the vehicle body controller20and the scan matching navigation position output controller33is performed twice. Therefore, in the control system30, when a delay or the like occurs in the communication between the vehicle body controller20and the scan matching navigation position output controller33, there is a possibility that the position and the orientation of the dump truck2that the vehicle body controller20has received from the scan matching navigation position output controller33differ from the position and the orientation at the time of the control of the dump truck2by the vehicle body controller20.

FIG. 10is a diagram illustrating the dump truck2that moves while the delay or the like in communication occurs. In a case where the position of the dump truck2is P1at the time t1, the speed of the dump truck2detected by the speed sensor27is Vc1, and the angular speed of the dump truck2detected by the gyro sensor26is ω1. The time at which the speed Vc1and the angular speed ω1have been acquired is t1. The scan matching navigation position output controller33receives, by communication, the detection result of the gyro sensor26, the detection result of the speed sensor27, and the received detection result of the laser sensor24B and map information. Based on the pieces of received information, the scan matching navigation position output controller33calculates the position P1of the dump truck2at the time t1.

The vehicle body controller20receives the position P1of the dump truck2determined by the scan matching navigation position output controller33, and controls the traveling of the dump truck2based on the received position P1. The timing of when the vehicle body controller20starts controlling the traveling of the dump truck2based on the position P1is time t2. In such case, there is a time lag between the time t1and the time t2. Therefore, at the time t2, the vehicle body controller20controls the traveling based on the position P1of the dump truck2at the time t1and thus, the control of the traveling is not performed accurately.

Accordingly, by correcting the position P1of the dump truck2at the time t1determined by the scan matching navigation position output controller33, the vehicle body controller20calculates a corrected position P1cin which the dump truck2is likely to exist at the time t2, and generates a command for controlling the dump truck2based on the corrected position P1c. Details of a correcting method for the position will be described later. InFIG. 10, the actual position of the dump truck2at time t2is P2. Hereinafter, the time t1is appropriately referred to as first time t1, and the time t2is appropriately referred to as second time t2.

When a delay occurs in the communication between the vehicle body controller20and the scan matching navigation position output controller33, the second time t2is delayed compared to the first time t1. The difference Δt (=t2−t1) between the second time t2and the first time t1is referred to as delay time. The delay time Δt includes a communication delay of when the vehicle body controller20receives positional information, which is information of the position P1at the t1, from the scan matching navigation position output controller33, and includes a delay caused by the position calculation processing in the scan matching navigation position output controller33. The delay time may include a communication delay of when the scan matching navigation position output controller33receives the detection results of the gyro sensor26and the speed sensor27from the vehicle body controller20. In addition, the delay time Δt may include, for example, a delay caused by instantaneous interruption of the communication between the vehicle body controller20and the scan matching navigation position output controller33.

Moreover, the delay time Δt may include, other than the delay in communication, a delay caused due to the difference between a control cycle of the vehicle body controller20and a control cycle of the scan matching navigation position output controller33. For example, when the control cycle of the scan matching navigation position output controller33is longer than the control cycle of the vehicle body controller20, there is a possibility that the positional information that the vehicle body controller20received from the scan matching navigation position output controller33is a control cycle in the past compared to the control cycle in which the vehicle body controller20controls the dump truck2. In other words, the vehicle body controller20belatedly receives the positional information determined by the scan matching navigation position output controller33. The delay time Δt may include the delay described above.

The dump truck2moves from the position P1to the position P2during the delay time Δt. As the delay time Δt increases, the distance between the position P2and the position P1gets longer. In a case of controlling the dump truck2at the position P2, the vehicle body controller20uses the position that the scan matching navigation position output controller33has determined, that is, the position P1. As a result, there is a possibility that the accuracy of the vehicle body controller20to control the dump truck2reduces as the distance between the actual position P2of the dump truck2at the timing of when the vehicle body controller20controls the dump truck2and the position P1gets longer.

The vehicle body controller20of the control system30corrects the position P1using the delay time Δt. Then, the vehicle body controller20causes the dump truck2to autonomously travel by generating and outputting the command that controls the dump truck2using the corrected position P1c, which is the position after the correction. Next, an example of processing in which the control system30determines the position of the dump truck2using the delay time will be described.

<Exemplary Processing of Control System30>

FIG. 11is a flowchart describing exemplary processing of when the control system30according to the embodiment executes a control method for a work machine according to the embodiment.FIG. 12is a diagram for describing an exchange of information between the vehicle body controller20and the scan matching navigation position output controller33.

In a case where the control system30causes the dump truck2to autonomously travel, in step S101, the vehicle body controller20outputs information IFs for the scan matching navigation position output controller33to determine the position P1of the dump truck2. In the embodiment, the information IFs is the angular speed ω1, which is the detection value of the gyro sensor26, and the speed Vc1, which is the detection value of the speed sensor27. Hereinafter, the information IFs is appropriately referred to as vehicle body information IFs.

In the embodiment, the vehicle body controller20outputs the vehicle body information IFs to the first signal line35together with the first time t1at which the vehicle body information IFs has been acquired. According to the processing described above, the vehicle body controller20transmits the first time t1at which the vehicle body information IFs has been acquired, and the vehicle body information IFs to the scan matching navigation position output controller33. In the embodiment, the vehicle body controller20transmits the vehicle body information IFs to the scan matching navigation position output controller33in the control cycle in which the vehicle body information IFs has been received. Moreover, in the embodiment, the first time t1at which the vehicle body information IFs has been acquired is the time when the vehicle body information IFs has been transmitted to the scan matching navigation position output controller33. The first time t1may be the time when the vehicle body controller20has received the detection results from the gyro sensor26and the speed sensor27.

The first time t1and the vehicle body information IFs are, as illustrated inFIG. 12, output from the vehicle body controller20as first information IF1. In the embodiment, the first information IF1includes the first time t1and the vehicle body information IFs. In step S102, the laser sensor24B outputs a detection result RT.

In step S103, the scan matching navigation position output controller33receives the first information IF1, the detection result RT of the laser sensor24B, and the map information of the map DB37(omitted inFIG. 11) by communicating with the vehicle body controller20via the first signal line35. As described above, since the first information IF1includes the vehicle body information IFs, in step S103, the scan matching navigation position output controller33receives the vehicle body information IFs from the vehicle body controller20. Then, in step S104, the scan matching navigation position output controller33determines the position P1of the dump truck2using the received vehicle body information IFs, and outputs the determined position P1as positional information IFp to the first signal line35.

The positional information IFp includes at least coordinates P1(X1, Y1) of the position P1of the dump truck2determined using the vehicle body information IFs included in the first information IF1. The positional information IFp may include an orientation angle θ of the dump truck2determined using the vehicle body information IFs. The orientation angle θ is information that indicates the orientation of the dump truck2at the position P1. In step S105, by outputting the positional information IFp to the first signal line35together with the first time t1included in the first information IF1, the scan matching navigation position output controller33transmits the positional information IFp to the vehicle body controller20. This means that the position of the dump truck at the first time t1is P1(X1, Y1).

The first time t1and the positional information IFp are, as illustrated inFIG. 12, output from the scan matching navigation position output controller33as second information IF2. In the embodiment, as illustrated inFIG. 14, the second information IF2includes the first time t1and the positional information IFp.

In step S106, the vehicle body controller20receives the second information IF2by communicating with the scan matching navigation position output controller33via the first signal line35. As described above, since the second information IF2includes the positional information IFp, in step S106, the vehicle body controller20receives the positional information IFp from the scan matching navigation position output controller33. Then, in step S107, the vehicle body controller20corrects the received position P1using the delay time Δt. In step S108, the vehicle body controller20generates the control command, which is the command for controlling the dump truck2, using the corrected position P1c, outputs the control command to the steering device2S and/or the traveling control device2D and thereafter, controls the dump truck2.

In step S107, the vehicle body controller20determines the corrected position P1cby correcting the position P1using the dead reckoning navigation. The correcting method will be described. In such case, the origin is the position P1. A moving distance from the position P1is determined from the product of the speed Vc1and the delay time Δt. The orientation from the position P1is determined from the angular speed ω1. In other words, the method for correcting the position of the dump truck2at the second time t2based on the position P1at the first time t1can be performed by the same method as the dead reckoning navigation.

The delay time Δt is the difference between the second time t2and the first time t1. The second time t2is the time when the vehicle body controller20starts calculating the command for controlling the dump truck2, and also the time when the position P1is corrected. The first time t1is the time when the vehicle body information IFs, which is for determining the position P1of the dump truck2, has been acquired, and the time before the second time t2, which is when the position P1is corrected.

In the embodiment, steps S101and S102do not necessarily have to be the same timing (first time t1). Moreover, the first time t1may be the time of output in step S101, the time of output in step S102, the time of acquisition of the information in step S103, the time of processing in step S104, or the time of output of the positional information IFp in step S105.

As illustrated inFIG. 12, based on the speed Vc1and the angular speed ω1, a position to which the dump truck2proceeds by a distance Vc1×Δt from the position P1that corresponds to the first time t1is the corrected position P1c. In other words, during the delay time Δt, the vehicle body controller20determines, using the dead reckoning navigation, the position to which the dump truck2has moved from the position P1received from the scan matching navigation position output controller33, and defines the determined position as a position after the correction, that is, the corrected position P1c. Thereafter, the vehicle body controller20controls the dump truck2using the corrected position P1c. Therefore, the influence of at least one of the delay caused by the communication between the vehicle body controller20and the scan matching navigation position output controller33, the delay caused by instantaneous interruption of the communication, the delay caused by a difference in the control cycles, the delay caused by the processing in the scan matching navigation position output controller33, and the like is reduced. As a result, reduction in accuracy when the vehicle body controller20controls the dump truck2is suppressed.

Modified Example

FIG. 13is a diagram illustrating a portion of a control system30aaccording to a modified example of the embodiment. In the control system30a, a gyro sensor26and a speed sensor27are connected, not only to a vehicle body controller20, but also to a scan matching navigation position output controller33. In the control system30a, an output from a clock42that counts time is input to the vehicle body controller20and the scan matching navigation position output controller33. With the structure described above, the vehicle body controller20and the scan matching navigation position output controller33operate in the same time system, that is, a time system of the clock42.

At first time t1, the scan matching navigation position output controller33acquires an angular speed ω1of a dump truck2from the gyro sensor26, and acquires a speed Vc1of the dump truck2from the speed sensor27. The scan matching navigation position output controller33determines a position P1of the dump truck2using vehicle body information IFs, i.e., the speed Vc1and the angular speed ω1, a detection result of a laser sensor24B, and map information of a map DB37. Specifically, coordinates P1(X1, Y1) of the position P1are determined. Then, together with the first time t1, the scan matching navigation position output controller33outputs positional information IFp including the coordinates P1(X1, Y1) as information IF3to a first signal line35. The information IF3is the same as second information IF2.

After receiving the information IF3via the first signal line35, the vehicle body controller20corrects the position P1that corresponds to the positional information IFp of the information IF3using dead reckoning navigation at second time t2. At this time, delay time Δt which is the difference between the second time t2and the first time t1is used. Thereafter, the vehicle body controller20controls the dump truck2using a corrected position P1cwhich is the position P1after the correction. As described above, also in the modified example, the scan matching navigation position output controller33determines the position using the vehicle body information IFs for determining the position P1. In addition, also in the modified example, in a case where the position P1is corrected by the dead reckoning navigation, the delay time Δt which is the difference between the second time t2, which is when the vehicle body controller20corrects the position P1, and the first time t1, which is the time before the second time t2and when the vehicle body information IFs has been acquired.

In the embodiment and the modified example thereof, the vehicle body controller20that controls the dump truck2corrects the position of the dump truck2determined by the scan matching navigation position output controller33using the delay time Δt including a delay of information transmission in the control system30, such as a delay of information transmission due to a delay in communication and the difference in the control cycles. Then, the vehicle body controller20controls the dump truck2using the corrected position P1cacquired by the correction. Therefore, the control system30can reduce the influence of the delay of the information transmission in the control system30. Specifically, the control system30can reduce the influence of the delay caused when the vehicle body controller20receives the information of the position P1from the scan matching navigation position output controller33. As a result, the control system30can suppress the delay caused when the vehicle body controller20controls the dump truck2and suppress the reduction in accuracy thereof even in the case where the delay occurs at the timing at which the vehicle body controller20acquires the position of the dump truck2due to the delay of communication or the like.

In the embodiment and the modified example, an example in which the working vehicle is the mining machine used in a mine has been described. However, the working vehicle is not limited to the mining machine. The working vehicle should at least include the traveling device23and the braking device2B. The working vehicle may be, for example, a working vehicle used in an underground mine and a working vehicle used at a work site on the ground. The working vehicle is considered to include the mining machine.

In the embodiment and the modified example, the working vehicle has been the dump truck2. However, the working vehicle may be a wheel loader, a grader, or a general vehicle3C. In addition, in the embodiment and the modified example, the dump truck2has been an unmanned dump truck. However, the dump truck2is not limited to this, and may be configured to assist an operation of a manned dump truck.

The method for the scan matching navigation position output controller33to determine the position of the dump truck2is also not limited to the embodiment and the modified example. As long as the method calculates a current position of the dump truck2by comparing the detection result by the non-contact sensor24with the map information37stored in advance, the method may be any method. In the embodiment and the modified example, the radar sensor and the laser sensor have been exemplified as the non-contact sensor24. However, the non-contact sensor24is not limited to these. For example, the non-contact sensor24may detect the situation around the dump truck2using a stereo camera or a mono camera.

In the embodiment and the modified example, the position of the working vehicle has been detected using the GPS detector. However, the detection of the position of the working vehicle is not limited to the GPS detector, and the position of the working vehicle may be detected based on a known positional information generation unit. In particular, the GNSS is not possible to be detected in an underground mine; therefore, for example, a self-position estimation or the like of the working vehicle that uses an indoor messaging system (IMES) which is a positional information generation unit, a pseudolite, a radio frequency identifier (RFID), a beacon, a survey instrument, a wireless LAN, an ultra wide band (UWB), a simultaneous localization and mapping (SLAM), or a landmark (a mark provided along the traveling path) may be used.

In the embodiment and the modified example, when the dump truck2is braked so as to be in a target speed at a target position, reduction in the accuracy required for the position of the working vehicle that has reached the target position can be suppressed while an impact generated on the dump truck2is suppressed. In particular, since the dump truck2used in the mine is large in mass, the impact is likely to be generated on the dump truck2at the time of braking. However, in the embodiment described above, the reduction in the accuracy of the position to stop or the like can be suppressed while the impact on the dump truck2is suppressed. Therefore, such embodiment is suitable for a large-scale working vehicle used in the mine.

The present embodiment and the modified example thereof have been described. However, the present embodiment and the modified example are not limited by the contents described above. The components described above include the one that can be easily envisioned by those skilled in the art, is substantially the same, and is within a so-called equivalent range. The components described above can be combined in any appropriate manner. Furthermore, at least one of various omissions, substitutions, and modifications of the components can be made without departing from the spirit of the embodiment and the modified example.

REFERENCE SIGNS LIST