Patent Publication Number: US-2023143733-A1

Title: Construction method and construction system

Description:
FIELD 
     The present disclosure relates to a construction method and a construction system. 
     BACKGROUND 
     In work machines such as excavators and bulldozers, work machines have widely used, each of which has a guide display function of displaying a guide indicating at least a current terrain or designed terrain of a construction range or a tooth-edge position of the work machine, or an automatic control function of automatically controlling working equipment (or intervention control in the operation of an operator) on the basis of the current terrain and the designed terrain of the construction range and position information about the work machine (e.g., see Patent Literatures 1 to 3). 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP 2012-172431 A 
     Patent Literature 2: WO 2016/111384 A 
     Patent Literature 3: WO 2017/115879 A 
     SUMMARY 
     Technical Problem 
     Although use of the work machines having the automatic control functions makes construction more efficient, there is room for improvement in efficiency. In addition, the work machines having the automatic control functions are relatively expensive to general work machines. Therefore, it is desired to suppress the number of the work machines having the automatic control functions used, for further improvement in construction efficiency. 
     The present disclosure has been made in view of the above, and an object of the present disclosure is to provide a construction method and a construction system that are configured to improve construction efficiency by using a work machine controlled by manual operation and a work machine having an automatic control function. 
     Solution to Problem 
     According to an aspect of the present invention, a construction method uses: a first work machine that is controlled by manual operation; and a second work machine that includes an automatic working-equipment control unit automatically controlling second working equipment based on at least one of a current terrain and a designed terrain of a construction range, and a tooth-edge position of the second working equipment, the construction method comprises: calculating a progress rate in the construction range for the first work machine based on the current terrain and the designed terrain of the construction range for the first work machine; and when the progress rate is equal to or larger than a threshold, the first work machine stops construction of the construction range, and the second work machine takes over the construction of the construction range from the first work machine. 
     According to an aspect of the present invention, a construction system uses: a first work machine that is controlled by manual operation; and a second work machine that includes an automatic working-equipment control unit automatically controlling second working equipment based on at least one of a current terrain and a designed terrain of a construction range, and a tooth-edge position of the second working equipment, the construction system comprises: a storage unit that stores the designed terrain of the construction range for the first work machine; an acquisition unit that acquires construction result data indicating a result of construction of the construction range for the first work machine; a progress rate calculation unit that calculates a progress rate of construction by the first work machine, based on the designed terrain of the construction range for the first work machine stored in the storage unit and the construction result data acquired by the acquisition unit; and an instruction unit that instructs the first work machine to stop construction of the construction range and that instructs the second work machine to take over the construction of the construction range, when the progress rate calculated by the progress rate calculation unit is equal to or larger than a threshold. 
     Advantageous Effects of Invention 
     According to an aspect of the present invention, it is possible to improve the construction efficiency by using the work machine controlled by manual operation and the work machine having the automatic control function. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic diagram illustrating an example of a construction system according to the present embodiment. 
         FIG.  2    is a schematic diagram illustrating an example of a construction range to which the construction system according to the present embodiment is applied. 
         FIG.  3    is a schematic diagram illustrating an excavator as a first work machine according to the present embodiment. 
         FIG.  4    is a schematic diagram illustrating the excavator as the first work machine according to the present embodiment. 
         FIG.  5    is a block diagram illustrating the excavator as the first work machine according to the present embodiment. 
         FIG.  6    is a block diagram illustrating an excavator as a second work machine according to the present embodiment. 
         FIG.  7    is a block diagram illustrating a server device of the construction system according to the present embodiment. 
         FIG.  8    is a block diagram illustrating the construction system according to the embodiment. 
         FIG.  9    is a flowchart illustrating an example of a construction method according to the present embodiment. 
         FIG.  10    is a flowchart illustrating an example of the construction method according to the present embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of a construction method and a construction system according to the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, component elements in the following embodiments include component elements that are easily replaceable by those skilled in the art or that are substantially equivalent. 
     &lt;Construction System&gt; 
       FIG.  1    is a schematic diagram illustrating an example of the construction system according to the present embodiment.  FIG.  2    is a schematic diagram illustrating an example of a construction range to which the construction system according to the present embodiment is applied. A construction system  1  uses an excavator  2  as a first work machine whose working equipment is operated by an operator, and an excavator  3  as a second work machine that is automatically controlled. More specifically, the construction system  1  includes a plurality of first work machines  2  operating in a construction site  1000 , one or more second work machines  3  operating in the construction site  1000 , an information terminal  5  installed in a construction company  1100 , and a server device  10 . In the construction site  1000 , the construction range is assigned to each of the plurality of first work machines  2  to perform construction. 
     &lt;First Work Machine&gt; 
       FIG.  3    is a schematic diagram illustrating the excavator as the first work machine according to the present embodiment.  FIG.  4    is a schematic diagram illustrating the excavator as the first work machine according to the present embodiment.  FIG.  5    is a block diagram illustrating the excavator as the first work machine according to the present embodiment. The first work machine  2  is a work machine having the working equipment (first working equipment), such as an excavator, a bulldozer, or a wheel loader. The first work machine  2  is controlled by manual operation. In the first work machine  2 , the working equipment is configured to be controlled only by manual operation, and no automatic control function of automatically controlling the working equipment is provided. The first work machine  2  desirably has a guide display function of displaying a guide indicating at least a current terrain or designed terrain of the construction range, or a tooth-edge position of the working equipment. The first work machine  2  may not have the guide display function. In the present embodiment, the excavator  2  will be described as an example of the first work machine. The excavator  2  includes a vehicle body  400  and the working equipment. In the excavator  2 , the working equipment is operated by the operator. In the present embodiment, the excavator  2  has the guide display function. The excavator  2  includes a display unit  29  that displays a guide indicating at least the current terrain or the designed terrain of the construction range in the construction site  1000 , the construction range being a construction target of the excavator  2 , and the tooth-edge position of the working equipment. 
     The excavator  2  includes a boom  431  that is connected to the vehicle body  400  via a boom pin  433 , and an arm  432  that is connected to the boom  431  via an arm pin  434 . A bucket  440  is connected to the arm  432  via a bucket pin  435 . 
     A length of the boom  431 , that is, a length between the boom pin  433  and the arm pin  434  is L 1 . A length of the arm  432 , that is, a length between the arm pin  434  and the bucket pin  435  is L 2 . A length of the bucket  440 , that is, a length between the bucket pin  435  and a tooth edge  440   p  of the bucket  440  is L 3 . 
     The excavator  2  includes a boom cylinder  411  that drives the boom  431 , an arm cylinder  412  that drives the arm  432 , a bucket cylinder  413  that drives the bucket  440 , a boom cylinder stroke sensor  421  that detects an amount of movement of the boom cylinder  411 , an arm cylinder stroke sensor  422  that detects an amount of movement of the arm cylinder  412 , and a bucket cylinder stroke sensor  423  that detects an amount of movement of the bucket cylinder  413 . The boom cylinders  411 , the arm cylinder  412 , and the bucket cylinder  413  are a hydraulic cylinder. The boom cylinder stroke sensor  421  detects boom cylinder length data that indicates a stroke length of the boom cylinder  411 . The arm cylinder stroke sensor  422  detects arm cylinder length data that indicates a stroke length of the arm cylinder  412 . The bucket cylinder stroke sensor  423  detects bucket cylinder length data that indicates a stroke length of the bucket cylinder  413 . 
     The vehicle body  400  of the excavator  2  is supported by an undercarriage  450 . The vehicle body  400  is an upper swing body that is swingable about a swing axis AX. The vehicle body  400  includes a cab provided with a driver&#39;s seat on which a driver sits. 
     The undercarriage  450  includes a crawler track. The tooth edge  440   p  is positioned at an end of the bucket  440 . In land grading and land cutting (excavation work), the tooth edge  440   p  comes into contact with the ground of the construction site  1000 . 
     An antenna  211  and an antenna  212  are mounted to the excavator  2 . The antenna  211  and the antenna  212  are used to detect a current position of the excavator  2 . The antenna  211  and the antenna  212  are electrically connected to a position detection device  21  that is a position detection unit for detecting the current position of the excavator  2 . 
     The excavator  2  includes a control system  200  that includes the position detection device  21 , a global coordinate calculation unit  22 , an inertial measurement unit (IMU)  23 , a sensor controller  24 , a controller  25 , and the display unit  29 . 
     The position detection device  21  detects an absolute position of the work machine. The position detection device  21  uses real time kinematic-global navigation satellite systems (RTK-GNSS, GNSS represents global navigation satellite system) to detect the current position of the excavator  2 . In the following description, the antenna  211  and the antenna  212  will be appropriately referred to a GNSS antenna  211  and a GNSS antenna  212 . Signals according to GNSS radio waves received by the GNSS antenna  211  and the GNSS antenna  212  are input to the position detection device  21 . The position detection device  21  detects installation positions of the GNSS antenna  211  and the GNSS antenna  212 . The position detection device  21  includes, for example, a three-dimensional position sensor. 
     The position detection device  21  includes the GNSS antenna  211  and the GNSS antenna  212  which are described above. Signals according to the GNSS radio waves received by the GNSS antenna  211  and the GNSS antenna  212  are input to the global coordinate calculation unit  22 . The GNSS antenna  211  receives reference position data P 1  indicating a position of the GNSS antenna  211 , from a positioning satellite. The GNSS antenna  212  receives reference position data P 2  indicating a position of the GNSS antenna  212 , from the positioning satellite. The GNSS antenna  211  and the GNSS antenna  212  receive the reference position data P 1  and the reference position data P 2  at a predetermined interval. The reference position data P 1  and the reference position data P 2  are information about positions where the GNSS antennas are installed. Whenever receiving the reference position data P 1  and the reference position data P 2 , the GNSS antenna  211  and the GNSS antenna  212  output the data to the global coordinate calculation unit  22 . 
     The global coordinate calculation unit  22  calculates position information about the work machine in a global coordinate system (XgYgZg coordinate system), from a result of the detection by the position detection device  21 . The global coordinate calculation unit  22  includes storage units such as RAM and ROM, and a processing unit such as CPU. The global coordinate calculation unit  22  generates swing body arrangement data indicating arrangement of the upper swing body of the excavator  2 , on the basis of the two pieces of reference position data P 1  and P 2 . In the present embodiment, the swing body arrangement data includes reference position data that is one of the two pieces of reference position data P 1  and P 2  and swing body orientation data that is generated on the basis of the two pieces of reference position data P 1  and P 2 . The swing body orientation data indicates an orientation in which the working equipment of the excavator  2  faces. The global coordinate calculation unit  22  updates the swing body arrangement data, that is, the reference position data and the swing body orientation data whenever acquiring the two pieces of reference position data P 1  and P 2  from the GNSS antenna  211  and the GNSS antenna  212  at the predetermined interval, and outputs the swing body orientation data to a display control unit  27 . 
     The IMU  23  detects an angular velocity and acceleration of the excavator  2 . The excavator  2  generates various accelerations, such as an acceleration generated during traveling, an angular acceleration generated during turning, and a gravitational acceleration, are generated with the movement thereof, but the IMU  23  detects and outputs at least the gravitational acceleration. Here, the gravitational acceleration is acceleration corresponding to drag force to gravity. The IMU  23  detects accelerations in the Xg-axis direction, the Yg-axis direction, and the Zg-axis direction, and angular velocities (rotation angular velocities) around the Xg-axis, the Yg-axis, and the Zg-axis, for example, in the global coordinate system. The IMU  23  outputs information acquired to the sensor controller  24 . 
     The inertial measurement unit (IMU)  24  is connected to the sensor controller  24 . The IMU  23  is provided in the vehicle body  400 . The IMU  23  acquires vehicle body inclination information such as pitch around the Yg axis and roll around the Xg axis of the excavator  2 , and outputs the information to the sensor controller  24 . The IMU  23  detects an inclination angle θ 4  of the vehicle body  400  in a left-right direction and an inclination angle θ 5  of the vehicle body  400  in a front-rear direction. 
     The sensor controller  24  includes storage units such as a random access memory (RAM) and a read only memory (ROM), and a processing unit such as a central processing unit (CPU). The sensor controller  24  calculates an inclination angle θ 1  of the boom  431  relative to a direction (Z-axis direction) orthogonal to a local coordinate system (XYZ coordinate system) of the excavator  2 , specifically, orthogonal to a horizontal plane (XY plane) in the local coordinate system of the vehicle body  400 , on the basis of the boom cylinder length detected by the boom cylinder stroke sensor  421 , and outputs the inclination angle θ 1  to a working equipment control unit  26  and the display control unit  27 . The sensor controller  24  calculates an inclination angle θ 2  of the arm  432  relative to the boom  431 , on the basis of the arm cylinder length detected by the arm cylinder stroke sensor  422 , and outputs the inclination angle θ 2  to the working equipment control unit  26  and the display control unit  27 . The sensor controller  24  calculates an inclination angle θ 3  of the tooth edge  440   p  of the bucket  440  included in the bucket  440  relative to the arm  432 , on the basis of the bucket cylinder length detected by the bucket cylinder stroke sensor  423 , and outputs the inclination angle θ 3  to the working equipment control unit  26  and the display control unit  27 . The inclination angles θ 1 , θ 2 , and θ 3  can be detected by a sensor other than the boom cylinder stroke sensor  421 , the arm cylinder stroke sensor  422 , and the bucket cylinder stroke sensor  423 . For example, an angle sensor such as a potentiometer can also detect the inclination angles θ 1 , θ 2 , and θ 3 . The sensor controller  24  calculates a relative position of the tooth edge  440   p  of the bucket  440  with respect to the vehicle body  400 , on the basis of the inclination angle θ 1 , the inclination angle θ 2 , the inclination angle θ 3 , the length L 1  of the boom  431 , the length L 2  of the arm  432 , and the length L 3  of the bucket  440 . 
     The IMU  23  is connected to the sensor controller  24 . The IMU  23  detects the vehicle body inclination information about the vehicle body such as the pitch around the Yg axis and the roll around the Xg axis of the excavator  2 . The vehicle body inclination information about the vehicle body of the excavator  2  indicates an attitude of the vehicle body. The IMU  23  is mounted in the vehicle body  400  of the excavator  2 . 
     The sensor controller  24  calculates an absolute position of the tooth edge  440   p  of the bucket  440  on the basis of the relative position of the tooth edge  440   p  of the bucket  440  with respect to the vehicle body  400  calculated by the sensor controller  24  and an absolute position of the vehicle body  400  acquired by the global coordinate calculation unit  22  and the IMU  23 . 
     The controller  25  includes the working equipment control unit  26 , the display control unit  27 , and a communication unit  28 . 
     The working equipment control unit  26  includes storage units such as RAM and ROM, and a processing unit such as CPU. On the basis of an amount of operation of the boom, an amount of operation of the bucket, and an amount of operation of the arm when the operator operates an operation unit, the working equipment control unit  26  controls the respective units of the working equipment. 
     The storage unit of the working equipment control unit  26  stores working equipment data about the excavator  2 . The working equipment data includes the length of the boom, the length of the arm, and the length of the bucket. Furthermore, the working equipment data includes minimum and maximum values of the inclination angle of the boom, the inclination angle of the arm, and the inclination angle of the bucket. Each of the inclination angles is preferably calculated by a known method. 
     The display control unit  27  provides the operator with information for excavating the ground in the construction range and forming the ground into a shape as indicated by designed terrain data which is described later. The display control unit  27  includes storage units such as RAM and ROM, and a processing unit such as CPU. The display control unit  27  acquires the reference position data and the swing body orientation data that are the swing body arrangement data, from the global coordinate calculation unit  22 . In the embodiment, the display control unit  27  generates bucket-tooth-edge position data that indicates a three-dimensional position of the tooth edge  440   p  of the bucket  440 . 
     The designed terrain data is terrain data about a final shape of a work target, that is, the construction target in the embodiment, of the working equipment of the excavator  2 . The work target of the working equipment is, for example, the ground. Examples of the work of the working equipment include, but are not limited to, excavation work and ground leveling work. 
     The display control unit  27  causes the display unit  29  to display as a guide screen, designed terrain data for the work target of the working equipment, on the basis of the designed terrain data acquired from the server device  10  described later. The display control unit  27  includes the communication unit  28 . The communication unit  28  is communicable with an external communication device. The communication unit  28  receives current terrain data and the designed terrain data from the server device  10  or the like. The communication unit  28  may receive the current terrain data and the designed terrain data about the construction site  1000 , from PC, a mobile terminal, or an external storage device such as a USB memory. 
     The guide screen is a screen that indicates a positional relationship between a cross-section of the designed terrain of the construction range and the bucket so that the operator readily recognizes the positional relationship therebetween. The guide screen provides the operator with information for operating the working equipment of the excavator  2  so that the ground as the work target has the same shape as that indicated by the cross-section of the designed terrain. 
     The display control unit  27  stores the designed terrain data created in advance in the construction company  1100 . The designed terrain data is information about a shape and a position of a three-dimensional designed terrain. The designed terrain indicates the final shape of the ground as the work target. The display control unit  27  causes the displays the display unit  29  to display the guide screen on the basis of the designed terrain data and information such as the results of the detection from the various sensors described above. 
     The display control unit  27  displays an instruction to the excavator  2  acquired from a handoff instruction unit  15  of the server device  10 . The instruction from the handoff instruction unit  15  will be described in detail later. 
     The display unit  29  is, for example, a liquid crystal display device that receives an input through a touch panel, but is not limited thereto. 
     &lt;Second Work Machine&gt; 
       FIG.  6    is a block diagram illustrating the excavator as the second work machine according to the present embodiment. The second work machine  3  is a work machine having the working equipment (second working equipment), such as an excavator, a bulldozer, or a wheel loader. The second work machine  3  has an automatic control function of automatically controlling working equipment on the basis of a current terrain and designed terrain of a construction range, and position information about the work machine. The second work machine  3  is automatically controllable to work instead of the excavator  2 , on the basis of an instruction to the excavator  3 , acquired from the handoff instruction unit  15  of the server device  10  which is described later. In the present embodiment, the excavator  3  will be described as an example of the second work machine. The excavator  3  includes a vehicle body and the working equipment. The excavator  3  has the automatic control function of automatically controlling the working equipment. The excavator  3  having the automatic control function for the working equipment makes it possible to perform construction highly accurately compared with that by the excavator  2  (first work machine). The excavator  3  includes an automatic working-equipment control unit  36  that automatically controls the working equipment on the basis of at least one of a current terrain and a designed terrain of the construction range and a tooth edge position of the working equipment. 
     In the present embodiment, the automatic control includes fully automatic control enabling unmanned construction and intervention control for intervention in operation by an operator. In the present embodiment, the excavator  3  will be described as having a fully automatic control function but is not limited thereto. The excavator  3  may have an intervention control function. In addition, the work machine is not limited to a type of work machine operated by the operator getting on the work machine and may be a type of work machine remotely operated by the operator not getting on the work machine. 
     The basic configuration of the excavator  3  is the same as that of the excavator  2 , and therefore, description of configurations of the excavator  3  that are the same as those of the excavator  2  will be omitted. 
     The excavator  3  includes a control system  300  that includes a position detection device  31 , a global coordinate calculation unit  32 , an IMU  33 , a sensor controller  34 , a controller  35 , and a display unit  39 . The position detection device  31 , the global coordinate calculation unit  32 , the IMU  33 , and the sensor controller  34  have similar configurations to those of the excavator  2 . 
     The controller  35  includes the automatic working-equipment control unit  36 , a display control unit  37 , and a communication unit  38 . 
     The automatic working-equipment control unit  36  includes storage units such as RAM and ROM, and a processing unit such as CPU. The automatic working-equipment control unit  36  causes the excavator  3  to work instead of the excavator  2 , on the basis of an instruction to the excavator  3 , acquired from the handoff instruction unit  15  of the server device  10  which is described later. The instruction from the handoff instruction unit  15  will be described in detail later. 
     The storage unit of the automatic working-equipment control unit  36  stores working equipment data about the excavator  3 . The working equipment data includes a length of a boom, a length of an arm, and a length of a bucket. Furthermore, the working equipment data includes minimum and maximum values of an inclination angle of the boom, an inclination angle of the arm, and an inclination angle of the bucket. Each of the inclination angles is preferably calculated by a known method. 
     The automatic working-equipment control unit  36  acquires designed terrain data from the display control unit  37 . The designed terrain data is information about the construction range that is a range in which the excavator  3  will work. The designed terrain data is data about the designed terrain which indicates a final shape of a work target of the working equipment. The designed terrain data is acquired from the server device  10  via the communication unit  38  and stored in the display control unit  37 . 
     The automatic working-equipment control unit  36  calculates a position of the tooth edge of the bucket (hereinafter, appropriately referred to as tooth-edge position), on the basis of an angle of the working equipment acquired from the sensor controller  34 . The automatic working-equipment control unit  36  automatically controls the operation of the working equipment on the basis of distance between the designed terrain data and the tooth edge of the bucket and speed of the working equipment so that the tooth edge of the bucket moves according to the designed terrain data. Note that as described above, the automatic control is not limited to the fully automatic control, and may be the intervention control for intervention in operation by the operator. The automatic working-equipment control unit  36  generates a boom command signal by using an amount of operation of the boom, an amount of operation of the arm, an amount of operation of the bucket, the designed terrain data acquired from the display control unit  37 , bucket-tooth-edge position data, and an inclination angle acquired from the sensor controller  34 , generates an arm command signal and a bucket command signal, if necessary, and drives various valves to control the working equipment. 
     The display control unit  37  displays information for excavating the ground in the construction range and forming the ground into a shape as indicated by the designed terrain data which is described later. The display control unit  37  includes storage units such as RAM and ROM, and a processing unit such as CPU. The display control unit  37  acquires the reference position data and the swing body orientation data that are the swing body arrangement data, from the global coordinate calculation unit  32 . In the embodiment, the display control unit  37  generates the bucket-tooth-edge position data that indicates a three-dimensional position of the tooth edge of the bucket. 
     The display control unit  37  stores the designed terrain data created in advance. The designed terrain data is information about the shape and position of the three-dimensional designed terrain. The designed terrain indicates the final shape of the ground as the work target. The display control unit  37  may cause the display unit  39  to display a guide screen or the like on the basis of the designed terrain data and information such as the results of detection from the various sensors described above. 
     The display control unit  37  displays an instruction to the excavator  3  acquired from the handoff instruction unit  15  of the server device  10  which is described later. 
     The display unit  39  is, for example, a liquid crystal display device that receives an input through a touch panel, but is not limited thereto. 
     &lt;Information Terminal&gt; 
     In the construction company  1100 , the information terminal  5  such as a personal computer is installed. In the construction company  1100 , the designed terrain of the construction site  1000  is created. The designed terrain indicates the final shape of the ground in the construction site  1000 . A worker of the construction company  1100  creates the designed terrain data two-dimensionally or three-dimensionally by using the information terminal  5 . 
     &lt;Server Device&gt; 
       FIG.  7    is a block diagram illustrating the server device of the construction system according to the present embodiment. The server device  10  is configured to perform data communication with the excavator  2  and the excavator  3  in the construction site  1000  through an input/output interface circuit  105 . The server device  10  is configured to perform data communication with the construction company  1100  through the input/output interface circuit  105 . The server device  10  includes a processor  101  that includes a current terrain data acquisition unit  11 , a designed terrain data acquisition unit  12 , a construction result data acquisition unit (acquisition unit)  13 , a progress rate calculation unit  14 , and the handoff instruction unit (instruction unit)  15 . 
     The current terrain data acquisition unit  11  acquires the current terrain data indicating the current terrain of each construction range in the construction site  1000 . The current terrain data is generated, for example, by measuring the current terrain of the construction range in the construction site  1000  by using a known measurement method. An example of the measurement method includes a method of measuring the current terrain by using the position information about a vehicle traveling in the construction site  1000 , a method of measuring the current terrain by using position information about the tooth edge of the working equipment of the work machine such as the excavator  2  constructing the construction site  1000 , a method of measuring the current terrain by running a surveying vehicle, a method of measuring the current terrain by using a stationary surveying instrument, a method of measuring the current terrain by using a stereo camera, a method of measuring the current terrain by using a three-dimensional laser scanner device, or a method of measuring the current terrain by using an unmanned aerial vehicle such as a drone. Note that the measurement by the unmanned aerial vehicle such as the drone may use a method of capturing an image of the current terrain by using, for example, a stereo camera and measuring the current terrain data on the basis of a result of the image capturing, or may use a method of measuring the current terrain data by using a three-dimensional laser scanner. 
     The designed terrain data acquisition unit  12  acquires the designed terrain data indicating the designed terrain of the construction site  1000 . The designed terrain is created in the construction company  1100 . The designed terrain data acquisition unit  12  acquires the designed terrain data from the construction company  1100  via communication means such as the Internet. 
     The construction result data acquisition unit  13  acquires construction result data about the working equipment of the excavator  2 . The construction result data acquisition unit  13  acquires the construction result data indicating results of construction of the construction site  1000 . The construction result data is data indicating the results of construction of the construction range in the construction site  1000  by the excavator  2 . The excavator  2  acquires the construction result data about the excavator  2 . The excavator  2  is configured to detect a terrain as the results of construction, on the basis of a trajectory of the absolute position of the tooth edge of the working equipment making contact with the current terrain or a travel trajectory of the undercarriage such as the crawler track or a wheel. In the work machine such as the excavator  2 , the controller  25  is configured to compare the current terrain detected on the basis of the absolute position of the tooth edge with the designed terrain to calculate the construction result data indicating how much work has progressed (volume of soil having been excavated) with respect to the designed terrain. The construction result data acquisition unit  13  wirelessly acquires the construction result data from the excavator  2 . Note that the income of the construction result data may be obtained by stereo camera measurement by an unmanned aerial vehicle such as a drone or by a three-dimensional laser scanner, with no use of the excavator. 
     The progress rate calculation unit  14  calculates a progress rate in the construction range for the excavator  2 , on the basis of the designed terrain and the current terrain of the construction range for the excavator  2 . For example, the progress rate calculation unit  14  may calculate the progress rate on the basis of a distance in cross-section between the designed terrain and the current terrain, that is, a difference in thickness of the ground in cross-sectional view. More specifically, the progress rate calculation unit  14  may calculate the progress rate, on the basis of a distance between a cross-section indicated by the current terrain data acquired by the current terrain data acquisition unit  11  and a cross-section indicated by the designed terrain data acquired by the designed terrain data acquisition unit  12 . 
     Alternatively, for example, the progress rate calculation unit  14  may calculate, as the progress rate, a ratio of the volume of soil having been excavated by the excavator  2  to a target volume of soil to be excavated by the excavator  2  in the construction range. More specifically, the progress rate calculation unit  14  may calculate, as the progress rate, a ratio of the volume of soil having been excavated included in the construction result data acquired by the construction result data acquisition unit  13  to the target volume of soil. 
     The target volume of soil is a value obtained as an amount of soil being a difference between the current terrain and the designed terrain of the construction range, and is stored in a storage device  102  of the server device  10  which is described later. For example, in a case where the final shape of the construction range is set, the target volume of soil corresponding to the final shape is set. For example, in a case where a target shape for a predetermined period is set, the target volume of soil for the predetermined period may be set. For example, in a case where a daily target shape is set, a daily target volume of soil may be set. 
     The target volume of soil may be, for example, numerical data indicating a volume of earth and sand excavated in the construction range, represented by a numerical value, or image data indicating a volume of earth and sand excavated in the construction range. 
     The progress rate calculation unit  14  calculates a progress rate in the construction site  1000  on the basis of the current terrain data, the designed terrain data, and the construction result data. The progress rate calculation unit  14  calculates the progress rate for each construction range in the construction site  1000 , that is, for each excavator  2 . More specifically, the progress rate calculation unit  14  calculates the volume of soil having been excavated by the working equipment of the excavator  2  on the basis of the construction result data acquired by the construction result data acquisition unit  13 . Then, the progress rate calculation unit  14  calculates a progress rate of construction by the working equipment of the excavator  2  on the basis of the target volume of soil stored in the storage device  102  of the server device  10  and the calculated volume of soil having been excavated. 
     On the basis of the designed terrain data, the handoff instruction unit  15  outputs a control signal for causing the excavator  3  as the second work machine to take over construction from the excavator  2  as the first work machine. More specifically, when the progress rate calculated by the progress rate calculation unit  14  is equal to or larger than a threshold, the handoff instruction unit  15  instructs the excavator  2  as the first work machine to stop construction of the construction range and to leave the construction range. In addition, the handoff instruction unit  15  instructs the excavator  3  as the second work machine to take over the construction of the construction range. 
     The threshold of the progress rate is preferably set for each excavator  2 . For example, in a case where the final shape of the construction range is set, the threshold of the progress rate for the final shape is set. For example, in a case where the target shape for a predetermined period is set, the threshold of the progress rate for the target shape for the predetermined period is set. For example, in a case where a daily target shape is set, the threshold of the progress rate for the daily target shape is set. The threshold of the progress rate is configured to be set via an input device (input unit)  103  of the server device  10 . 
     When a plurality of excavators  2  is determined to have the progress rate equal to or larger than the threshold, the handoff instruction unit  15  may instruct the excavator  3  to take over the construction of the construction range from the excavator  2  closest to the excavator  3 . 
     &lt;Hardware Configuration&gt; 
       FIG.  8    is a block diagram illustrating the construction system according to the embodiment. The server device  10  includes the processor  101  such as CPU, the storage device  102  that includes an internal memory such as ROM or RAM and an external memory such as a hard disk device, the input device  103  that includes an input device such as a keyboard, mouse, and touch panel, an output device  104  that includes a display device such as a flat panel display device, and a printer such as an inkjet printer, and the input/output interface circuit  105  that includes a wired communication device or wireless communication device. The input device  103  is configured to receive an operation to input the threshold of the progress rate. The input threshold of the progress rate is stored in the storage device  102 . 
     The excavator  2  operating in the construction site  1000  includes a processor  201 , a storage device  202 , and an input/output interface circuit  203  that includes a wired communication device or a wireless communication device. 
     The excavator  3  operating in the construction site  1000  includes a processor  301 , a main memory  302 , a storage  303 , and an input/output interface circuit  304  that includes a wired communication device or a wireless communication device. 
     The information terminal  5  installed in the construction company  1100  includes a processor  501 , a storage device  502 , an input device  503 , an output device  504 , and an input/output interface circuit  505  that includes a wired communication device or a wireless communication device. 
     The server device  10  is configured to perform data communication with the excavator  2  and the excavator  3  in the construction site  1000 . The excavator  2  and the excavator  3  perform wireless data communication with the server device  10  via a communication satellite or a mobile phone. Note that the excavator  2  and the excavator  3  may perform wireless data communication with the server device  10  by using another communication system such as wireless LAN including Wi-Fi. 
     The server device  10  is configured to perform data communication with the information terminal  5  in the construction company  1100 . The information terminal  5  performs wireless data communication with the server device  10  via a communication satellite or a mobile phone. Note that the information terminal  5  may perform wireless data communication with the server device  10  by using another communication system such as wireless LAN including Wi-Fi. 
     &lt;Construction Method&gt; 
     Next, the construction method using the construction system  1  will be described.  FIG.  9    is a flowchart illustrating an example of the construction method according to the present embodiment.  FIG.  10    is a flowchart illustrating an example of the construction method according to the present embodiment. In the present embodiment, the construction method uses the excavator  2  as the first work machine whose working equipment is operated by the operator, and the excavator  3  as the second work machine whose working equipment is automatically controlled. Here, the ratio of the volume of soil having been excavated to the target volume of soil to be excavated by the excavator  2  in the construction range is described as being calculated as the progress rate. 
     The server device  10  acquires the current terrain data indicating the current terrain of the construction site  1000  by the current terrain data acquisition unit  11  (Step SP 1 ). The current terrain data can be measured using a known measurement method, and the measurement method is not limited. 
     The server device  10  acquires the designed terrain data indicating the designed terrain of the construction site  1000  from the construction company  1100  by using the designed terrain data acquisition unit  12  (Step SP 2 ). 
     The server device  10  performs progress monitoring processing for all excavators  2  operating in the construction site  1000  (Step SP 3 ). More specifically, the server device  10  performs the processing of Steps SP 10  to SP 50  for all excavators  2  operating in the construction site  1000 , according to the flowchart illustrated in FIG.  10 . 
     The server device  10  acquires a working equipment ID allowing identification of each excavator  2  and the position information about the excavator  2 , from the excavator  2  (Step SP 10 ). The working equipment ID can be acquired, for example, during communication between the server device  10  and the excavator  2 . Note that, in a case where the construction range for the excavator  2  is set in advance and is known and the position of the excavator  2  can be estimated on the basis of the construction range, the acquisition of the position information may be omitted. 
     The server device  10  acquires the construction result data indicating the results of construction of the construction range for the excavator  2  in the construction site  1000 , by using the construction result data acquisition unit  13  (Step SP 20 ). A method of acquiring the construction result data is not limited. 
     The server device  10  calculates the progress rate in each construction range in the construction site  1000  on the basis of the current terrain data, the designed terrain data, and the construction result data, by using the progress rate calculation unit  14  (Step SP 30 ). More specifically, the progress rate calculation unit  14  calculates the progress rate indicating the volume of soil having been excavated by the excavator  2  to the target volume of soil to be excavated by the excavator  2  in the construction range. 
     The server device  10  determines whether the progress rate calculated by the progress rate calculation unit  14  is equal to or larger than the threshold set for the excavator  2  (Step SP 40 ). When it is determined that the progress rate is equal to or larger than the threshold (Yes in Step SP 40 ), the process proceeds to Step SP 50 . When it is not determined that the progress rate is equal to or larger than the threshold (No in Step SP 40 ), the process is finished. 
     When it is determined that the progress rate is equal to or larger than the threshold (Yes in Step SP 40 ), the server device  10  causes the excavator  3  as the second work machine to perform construction instead of the excavator  2  as the first work machine, by using the handoff instruction unit  15  (Step SP 50 ). More specifically, the handoff instruction unit  15  outputs a control signal instructing the excavator  2  to stop the construction of the construction range and to leave the construction range. The excavator  2  that has received the instruction from the handoff instruction unit  15  stops the construction of the construction range and leaves the construction range according to the operation by the operator. In addition, the handoff instruction unit  15  outputs, to the excavator  3 , the control signal for instructing the excavator  3  to take over the construction of the construction range from the excavator  2 . The excavator  3  having received the instruction from the handoff instruction unit  15  moves to the construction range, and performs construction of the construction range taken over from the excavator  2  while controlling the working equipment on the basis of the designed terrain data. 
     &lt;Effects&gt; 
     In the present embodiment, when the progress rate of the construction range for the excavator  2  is equal to or larger than the threshold, the excavator  2  stops the construction of the construction range, and the excavator  3  takes over the construction of the construction range from the excavator  2 . In the present embodiment, in a step of finishing the construction range where the progress rate is equal to or larger than the threshold, it is possible for the excavator  3  configured to perform highly accurate construction to perform the construction instead. In this way, according to the present embodiment, it is possible to improve the efficiency of construction by using the excavator  2  having the guide display function and operated by the operator and the excavator  3  having the automatic control function. 
     In the present embodiment, the threshold of the progress rate is set for each excavator  2 . According to the present embodiment, the excavator  3  is configured to perform construction instead at an appropriate timing, according to each excavator  2  arranged in the construction site  1000 . 
     In the present embodiment, when a plurality of excavators  2  is determined to have the progress rate equal to or larger than the threshold, the excavator  3  may take over the construction of the construction range from the excavator  2  closest to the excavator  3 . According to the present embodiment, construction efficiency in the construction site  1000  can be further improved. 
     Note that, in the present embodiment, when it is determined that the progress rate is equal to or larger than the threshold, the server device  10  may not only cause the excavator  3  as the second work machine to perform construction instead of the excavator  2  as the first work machine but also instruct a transport machine such as a dump truck to move to the vicinity of the construction range for the excavator  2 . This configuration makes it possible to efficiently carry the excavated earth and sand generated in the construction by the excavator  2  by the transport machine. 
     &lt;Modifications&gt; 
     In the above description, one excavator  3  is used but the present invention is not limited thereto. A plurality of excavators  3  may be used. In this case, for example, an excavator  3  closest to an excavator  2  whose progress rate is determined to be equal to or larger than the threshold may be instructed to take over the construction from the excavator  2 . 
     REFERENCE SIGNS LIST 
     
         
         
           
               1  CONSTRUCTION SYSTEM 
               10  SERVER DEVICE 
               11  CURRENT TERRAIN DATA ACQUISITION UNIT 
               12  DESIGNED TERRAIN DATA ACQUISITION UNIT 
               13  CONSTRUCTION RESULT DATA ACQUISITION UNIT (ACQUISITION UNIT) 
               14  PROGRESS RATE CALCULATION UNIT 
               15  HANDOFF INSTRUCTION UNIT (INSTRUCTION UNIT) 
               2  EXCAVATOR (FIRST WORK MACHINE) 
               21  POSITION DETECTION DEVICE 
               22  GLOBAL COORDINATE CALCULATION UNIT 
               23  IMU 
               24  SENSOR CONTROLLER 
               25  CONTROLLER 
               26  WORKING EQUIPMENT CONTROL UNIT 
               27  DISPLAY CONTROL UNIT 
               29  DISPLAY UNIT 
               3  EXCAVATOR (SECOND WORK MACHINE) 
               31  POSITION DETECTION DEVICE 
               32  GLOBAL COORDINATE CALCULATION UNIT 
               33  IMU 
               34  SENSOR CONTROLLER 
               35  CONTROLLER 
               36  AUTOMATIC WORKING-EQUIPMENT CONTROL UNIT 
               37  DISPLAY CONTROL UNIT 
               39  DISPLAY UNIT