Patent Publication Number: US-2023138735-A1

Title: Display system, program, and method for controlling display system

Description:
TECHNICAL FIELD 
     The present disclosure relates to a display system, a program, and a method for controlling the display system. 
     BACKGROUND ART 
     In a hydraulic excavator, a working implement including a bucket is driven by an operator who operates an operation lever. At this time, it is difficult for the operator to perform excavation such that the operator obtains target construction topography while visually checking movement of the working implement and the current topography. Accordingly, technique for supporting the operation of the operator is required. 
     For example, WO 2015/030266 (PTL 1) discloses a display system of a working machine that provides information about a construction state to the operator. In this display system, a side view of the bucket is displayed on a display unit together with an image of the target construction topography. 
     CITATION LIST 
     Patent Literature 
     
         
         PTL 1: WO 2015/030266 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     In order to support the operator who performs an excavation operation using the working machine, a positional relationship between a target topography and an excavation tool is desirably provided in a visually more understandable manner. 
     An object of the present disclosure is to provide a display system, a program, and a control method of the display system capable of providing the positional relationship between the target topography and the excavation tool in the visually more easily understandable manner. 
     Solution to Problem 
     A display system according to one aspect of the present disclosure includes a display and a controller. The controller displays a third figure representing a relative relationship between a first figure indicating an inclination of a part of an excavation tool and a second figure indicating an inclination of a target topography on the display. 
     A display system according to another aspect of the present disclosure includes a display and a controller. The controller displays a first figure that is a straight line extended from a bottom surface of a bucket in side view of the bucket and a second figure that indicates an inclination of a target topography. 
     A program according to still another aspect of the present disclosure causes a processor of a controller to execute generating a first figure indicating an inclination of a part of an excavation tool, generating a second figure indicating an inclination of a target topography, generating a third figure representing a relative relationship between the first figure and the second figure, and displaying the third figure on a display. 
     A method for controlling a display system according to yet another aspect of the present disclosure, the method includes the following steps. 
     A first figure indicating an inclination of a part of an excavation tool is generated. A second figure indicating an inclination of a target topography is generated. A third figure representing a relative relationship between the first figure and the second figure is generated. The third figure is displayed on a display. 
     Advantageous Effects of Invention 
     The display system, the program, and the control method for controlling the display system capable of providing a positional relationship between the target topography and the excavation tool in the visually more easily understandable manner can be implemented according to the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a perspective view illustrating a configuration of a hydraulic excavator as an example of a working machine according to an embodiment. 
         FIG.  2    is a side view of the hydraulic excavator. 
         FIG.  3    is a rear view of the hydraulic excavator. 
         FIG.  4    is a block diagram illustrating a control system included in a display system of the embodiment. 
         FIG.  5    is a view illustrating a target construction topography and a target topography. 
         FIG.  6    is a view illustrating an image in which a support image is displayed with a bucket as a center in a side view of the hydraulic excavator as a first example of a support screen displayed on a display unit. 
         FIG.  7    is a view illustrating the image at a viewpoint of the bucket and the target topography viewed from an operator who operates the hydraulic excavator as a second example of the support screen displayed on the display unit. 
         FIG.  8    is a view illustrating the image in which the support image is displayed with a vehicle body as the center in the side view of the hydraulic excavator as a third example of the support screen displayed on the display unit. 
         FIGS.  9 (A) to  9 (E)  illustrate a method for generating the support image in order of steps. 
         FIGS.  10 (A) to  10 (E)  are views illustrating the method for generating the support image in the side view of the hydraulic excavator in the order of steps subsequent to the steps in  FIG.  9   . 
         FIGS.  11 (A) to  11 (E)  are views illustrating the method for generating the support image at the viewpoint form the bucket and the target topography from the operator who operates the hydraulic excavator in the order of steps subsequent to the steps in  FIG.  9   . 
         FIG.  12    is a flowchart illustrating a method for controlling the display system in the embodiment. 
         FIG.  13    is a view illustrating the image in which the support image indicating an extension line of a bucket bottom surface is displayed in the side view of the hydraulic excavator as a modification of the support screen displayed on the display unit. 
         FIG.  14    is a view illustrating a tilt bucket. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. In the specification and the drawings, the same components or corresponding components are denoted by the same reference numerals, and redundant description will not be repeated. In the drawings, the configuration may be omitted or simplified for convenience of description. In addition, at least a part of the embodiment and each modification may be arbitrarily combined with each other. 
     &lt;Overall Configuration of Working Machine&gt; 
     With reference to  FIG.  1   , a configuration of a hydraulic excavator as an example of a working machine to which the idea of the present disclosure can be applied will be described. The present disclosure is also applicable to a working machine having an excavation tool other than the following hydraulic excavator. 
     In the following description, a front-rear direction is a front-rear direction of the operator seated on a driver&#39;s seat  4 S in an operator cab  4  in  FIG.  1   . A direction facing the operator seated on driver&#39;s seat  4 S is a forward direction, and a direction behind the operator seated on driver&#39;s seat  4 S is a backward direction. A left-right direction is a left-right direction of the operator seated on driver&#39;s seat  4 S. A right side and a left side when the operator sits on driver&#39;s seat  4 S faces a front are a right direction and a left direction, respectively. A vertical direction is a direction orthogonal to a plane defined by the front-back direction and the left-right direction. In the vertical direction, a side on which the ground exists is a lower side, and a side on which the sky exists is an upper side. 
       FIG.  1    is a perspective view illustrating the configuration of the hydraulic excavator as an example of the working machine according to an embodiment.  FIGS.  2  and  3    are a side view and a rear view of the hydraulic excavator. 
     As illustrated in  FIG.  1   , a hydraulic excavator  100  as the working machine in the embodiment includes a machine body  1  and a working implement  2 . Machine body  1  includes a revolving body  3  and a traveling device  5 . Revolving body  3  accommodates devices such as a power generator and a hydraulic pump (not illustrated) in a machine chamber  3 EG. Machine chamber  3 EG is disposed on a rear end side of revolving body  3 . 
     For example, hydraulic excavator  100  includes an internal combustion engine such as a diesel engine as a power generation device, but hydraulic excavator  100  is not limited to such the internal combustion engine. For example, hydraulic excavator  100  may include what is called a hybrid type power generation device in which the internal combustion engine, a generator motor, and a power storage device are combined. 
     Revolving body  3  includes operator cab  4 . Operator cab  4  is mounted on a front end side of revolving body  3 . Operator cab  4  is disposed on a side opposite to a side where machine chamber  3 EG is disposed. A display input device  38  and an operation device  25  are disposed in operator cab  4  (see  FIG.  4   ). These will be described later. 
     Traveling device  5  is disposed below revolving body  3 . Traveling device  5  includes crawler belts  5   a ,  5   b . Traveling device  5  causes hydraulic excavator  100  to travel by a hydraulic motor  5   c  rotationally driving crawler belts  5   a ,  5   b . Hydraulic excavator  100  may have tires instead of crawler belts  5   a ,  5   b , or may be a wheel type hydraulic excavator. 
     A handrail  9  is provided on revolving body  3 . Two GNSS antennas  21 ,  22  for real time kinematic-global navigation satellite systems (RTK-GNSS) are detachably attached to handrail  9 . 
     For example, GNSS antennas  21 ,  22  are installed at a certain distance from each other along an axis parallel to a Ya-axis of a machine body coordinate system [Xa, Ya, Za]. GNSS antennas  21 ,  22  may be installed at a certain distance from each other along the axis parallel to an Xa-axis of machine body coordinate system [Xa, Ya, Za]. 
     GNSS antennas  21 ,  22  are preferably installed at positions as far away from each other as possible from the viewpoint of improving detection accuracy of the current position of hydraulic excavator  100 . In addition, GNSS antennas  21 ,  22  are preferably installed at positions that do not obstruct a field of view of the operator as much as possible. GNSS antennas  21 ,  22  may be installed on revolving body  3  and behind a counterweight  3 CW or operator cab  4 . 
     Working implement  2  is attached to a lateral side of operator cab  4  of revolving body  3 . Working implement  2  includes a boom  6 , an arm  7 , a bucket  8 , a boom cylinder  10 , an arm cylinder  11 , and a bucket cylinder  12 . A base end of boom  6  is rotatably attached to the front of machine body  1  through a boom pin  13 . A base end of arm  7  is rotatably attached to a tip of boom  6  through an arm pin  14 . Bucket  8  is attached to the distal end of arm  7  through a bucket pin  15 . 
     Bucket  8  includes a plurality of blades  8 B. The plurality of blades  8 B are attached to an end of bucket  8  on the side opposite to the side on which bucket pin  15  is attached. The plurality of blades  8 B are attached to the end of bucket  8  farthest from the side to which bucket pin  15  is attached. The plurality of blades  8 B are arrayed in a row in the direction parallel to bucket pin  15 . Blade edge  8 T is the tip of blade  8 B. Blade edge  8 T is the tip of bucket  8  at which working implement  2  generates excavation force. The direction parallel to a straight line connecting the plurality of blade edges  8 T is a width direction of bucket  8 . The width direction of bucket  8  is matched with the width direction of revolving body  3 , namely, the left-right direction of revolving body  3 . 
     Bucket  8  is coupled to bucket cylinder  12  through a pin  16 . Bucket cylinder  12  expands and contracts to rotate bucket  8 . Bucket  8  rotates about an axis orthogonal to the extending direction of arm  7 . Boom pin  13 , arm pin  14 , and bucket pin  15  are disposed in a positional relationship parallel to each other. That is, the center axes of the pins are parallel to each other. 
     Each of boom cylinder  10 , arm cylinder  11 , and bucket cylinder  12  is a hydraulic cylinder. Each of boom cylinder  10 , arm cylinder  11 , and bucket cylinder  12  operates by adjusting the expansion and contraction and speed according to pressure or a flow rate of a hydraulic oil. 
     Boom cylinder  10  operates boom  6 , and vertically rotates boom  6  about the center axis of boom pin  13 . Arm cylinder  11  operates arm  7 , and rotates arm  7  about the center axis of arm pin  14 . Bucket cylinder  12  operates bucket  8 , and rotates bucket  8  about the center axis of bucket pin  15 . 
     The excavation tool of working machine  100  is not limited to bucket  8 , but may be another excavation tool such as a breaker. 
     As illustrated in  FIG.  2   , a length of boom  6  (a length between boom pin  13  and arm pin  14 ) is L 1 . The length of arm  7  (the length from the center axis of arm pin  14  to a center axis AX 1  of bucket pin  15 ) is L 2 . The length of bucket  8  (the length from center axis AX 1  of bucket pin  15  to blade edge  8 T) is L 3 . The length of bucket  8  is the length along an axis AX 3  orthogonal to center axis AX 1  of bucket pin  15  and passing through blade edge  8 T of bucket  8 . 
     An inertial measurement unit (IMU)  18 A is disposed on boom  6 . An IMU  18 B is disposed in arm  7 . An IMU  18 C is disposed in bucket  8 . Each of IMUs  18 A,  18 B,  18 C is a working implement posture sensor that detects a posture of working implement  2 . Each of IMUs  18 A,  18 B,  18 C detects a triaxial angle (or angular velocity) and acceleration. 
     The postures of boom  6 , arm  7 , and bucket  8  can be detected from the triaxial angles (or angular velocities) and accelerations detected by IMUs  18 A,  18 B,  18 C. Specifically, an inclination angle θ1 of boom  6  with respect to the Za-axis of the machine body coordinate system described later can be calculated from the triaxial angle (or angular velocity) and acceleration detected by IMU  18 A. An inclination angle θ2 of arm  7  with respect to boom  6  can be calculated from the triaxial angle (or angular velocity) and acceleration detected by IMU  18 B. An inclination angle θ3 of bucket  8  with respect to arm  7  can be calculated from the triaxial angle (or angular velocity) and acceleration detected by IMU  18 C. 
     The working implement posture sensor is not limited to the IMU, but may be a stroke sensor, a potentiometer, an imaging device, or the like. The working implement posture sensors may be hydraulic sensors  37 SBM,  37 SBK,  37 SAM in  FIG.  4   . 
     Machine body  1  includes a position detector  19 . Position detector  19  detects the current position of hydraulic excavator  100 . Position detector  19  includes GNSS antennas  21 ,  22 , an inclination angle sensor  24 , and a controller  39 . Position detector  19  may include a three-dimensional position sensor. 
     Revolving body  3  and working implement  2  rotate with respect to traveling device  5  about a predetermined revolving center axis. Machine body coordinate system [Xa, Ya, Za] is a coordinate system of machine body  1 . In the embodiment, in machine body coordinate system [Xa, Ya, Za], a revolving center axis of working implement  2  or the like is defined as the Za-axis, an axis orthogonal to the Za-axis and parallel to an operation plane of working implement  2  is defined as the Xa-axis, and an axis orthogonal to the Za-axis and the Xa-axis is defined as the Ya-axis. For example, the operation plane of working implement  2  is a plane orthogonal to boom pin  13 . The Xa-axis corresponds to the front-rear direction of revolving body  3 , and the Ya-axis corresponds to the width direction of revolving body  3 . 
     A signal corresponding to a GNSS radio wave received by each of antennas  21 ,  22  is input to controller  39 . GNSS antenna  21  receives reference position data P 1  indicating an own installation position from a positioning satellite. GNSS antenna  22  receives reference position data P 2  indicating the own installation position from the positioning satellite. For example, GNSS antennas  21 ,  22  receive reference position data P 1 , P 2  at a cycle of 10 Hz. Reference position data P 1 , P 2  are information about the position where the GNSS antenna is installed. Each time GNSS antennas  21 ,  22  receive reference position data P 1 , P 2 , GNSS antennas  21 ,  22  output reference position data P 1 , P 2  to controller  39 . 
     As illustrated in  FIG.  3   , inclination angle sensor  24  is attached to revolving body  3 . Inclination angle sensor  24  detects an inclination angle θ4 of the width direction of machine body  1  with respect to the direction in which gravity acts, namely, vertical direction Ng. For example, inclination angle sensor  24  may be the IMU. 
     IMUs  18 A,  18 B,  18 C, GNSS antennas  21 ,  22 , inclination angle sensor  24 , display input device  38 , and controller  39  may be added to hydraulic excavator  100  as a retrofitted kit. Hereinafter, the hydraulic excavator equipped with the retrofitted kit is referred to as the hydraulic excavator  100 , and the hydraulic excavator not equipped with the retrofitted kit is referred to as a hydraulic excavator  100   a.    
     &lt;Display System&gt; 
     With reference to  FIGS.  4  and  5   , a display system of the embodiment will be described below. In the embodiment, the display system in the case where a retrofitted kit  100   b  is mounted on hydraulic excavator  100   a  later will be described as an example of the display system. 
     However, the display system of the present disclosure includes not only the case where retrofitted kit  100   b  is retrofitted to hydraulic excavator  100   a  after sale of hydraulic excavator  100   a , but also the case where retrofitted kit  100   b  is mounted on hydraulic excavator  100   a  from the beginning of the sale of hydraulic excavator  100 . 
       FIG.  4    is a block diagram illustrating a control system included in the display system of the embodiment.  FIG.  5    is a view illustrating a target construction topography and a target topography. As illustrated in  FIG.  4   , a display system  101  of the embodiment is a system that provides information constructing the target construction topography in  FIG.  5    for the operator during the excavation using hydraulic excavator  100 , and supports the operation of the operator. Display system  101  includes hydraulic excavator  100   a , retrofitted kit  100   b , and a server  40 . 
     Hydraulic excavator  100   a  includes operation device  25 , a working implement electronic control device  26 , a working machine control device  27 , and a hydraulic pump  47 . 
     Operation device  25  is a device that operates the operation of working implement  2  ( FIG.  1   ) and the traveling of hydraulic excavator  100   a . Operation device  25  includes working implement operation members  31 L,  31 R, traveling operation members  33 L,  33 R, working implement operation detectors  32 L,  32 R, and traveling operation detectors  34 L,  34 R. For example, working implement operation members  31 L,  31 R and traveling operation members  33 L,  33 R are pilot-pressure type levers, but are not limited thereto. For example, working implement operation members  31 L,  31 R and traveling operation members  33 L,  33 R may be electric type levers. 
     Working implement operation detectors  32 L,  32 R function as operation detectors that detect inputs to working implement operation members  31 L,  31 R as operation units. Traveling operation detectors  34 L,  34 R function as operation detectors that detect inputs to traveling operation members  33 L,  33 R as operation units. 
     Working machine control device  27  is a hydraulic device including a hydraulic control valve and the like. Working machine control device  27  drives and controls boom cylinder  10 , arm cylinder  11 , bucket cylinder  12 , a revolving motor, and hydraulic motor  5   c  based on the operation in operation device  25 . 
     Working machine control device  27  includes a traveling control valve  37 D and a working control valve  37 W. For example, each of traveling control valve  37 D and working control valve  37 W is a proportional control valve. Traveling control valve  37 D is controlled by the pilot pressure from traveling operation detectors  34 L,  34 R. Working control valve  37 W is controlled by the pilot pressure from working implement operation detectors  32 L,  32 R. 
     Working machine control device  27  includes hydraulic sensors  37 S 1   f ,  37 S 1   b ,  37 Srf,  37 Srb. Each of hydraulic sensors  37 S 1   f ,  37 S 1   b ,  37 Srf,  37 Srb detects magnitude of the pilot pressure supplied to traveling control valve  37 D and generates a corresponding electric signal. Hydraulic sensors  37 S 1   f ,  37 S 1   b ,  37 Srf, and  37 Srb function as operation detectors that detect inputs to traveling operation members  33 L,  33 R as operation units. 
     Hydraulic sensor  37 S 1   f  detects the pilot pressure for leftward forward movement. Hydraulic sensor  37 S 1   b  detects the pilot pressure for leftward backward movement. Hydraulic sensor  37 Srf detects the pilot pressure for rightward forward movement. Hydraulic sensor  37 Srb detects the pilot pressure for rightward backward movement. 
     When the operator operates traveling operation members  33 L,  33 R, the hydraulic oil having a flow rate corresponding to the pilot pressure generated in response to the operation flows out from traveling control valve  37 D. The hydraulic oil flowing out of traveling control valve  37 D is supplied to hydraulic motor  5   c  of traveling device  5 . Thus, crawler belts  5   a ,  5   b  are rotationally driven. 
     Working machine control device  27  includes hydraulic sensors  37 SBM,  37 SBK,  37 SAM,  37 SRM. Each of hydraulic sensors  37 SBM,  37 SBK,  37 SAM,  37 SRM detects the magnitude of the pilot pressure supplied to working control valve  37 W and generates a corresponding electric signal. Hydraulic sensors  37 SBM,  37 SBK,  37 SAM,  37 SRM function as operation detectors that detect inputs to working implement operation members  31 L,  31 R as operation units. 
     Hydraulic sensor  37 SBM detects the pilot pressure corresponding to boom cylinder  10 . Hydraulic sensor  37 SAM detects the pilot pressure corresponding to arm cylinder  11 . Hydraulic sensor  37 SBK detects a pilot pressure corresponding to bucket cylinder  12 . Hydraulic sensor  37 SRM detects the pilot pressure corresponding to the revolving motor. 
     When the operator operates working implement operation members  31 L,  31 R, the hydraulic oil having a flow rate corresponding to the pilot pressure generated in response to the operation flows out of working control valve  37 W. The hydraulic oil flowing out of working control valve  37 W is supplied to at least one of boom cylinder  10 , arm cylinder  11 , bucket cylinder  12 , and revolving motor. Thus, cylinders  10 ,  11 ,  12  expand and contract, and the revolving motor is revolved. 
     Working implement electronic control device  26  acquires the electric signal indicating the magnitude of the pilot pressure generated by working machine control device  27 . Working implement electronic control device  26  controls the engine and the hydraulic pump based on the acquired electric signal. In addition, working implement electronic control device  26  outputs the acquired electric signal to controller  39  in order to generate the support screen described later. For example, when the hydraulic sensors  37 SBM,  37 SBK,  37 SAM are used as the working implement posture sensors, working implement electronic control device  26  outputs the acquired electric signals of hydraulic sensors  37 SBM,  37 SBK,  37 SAM to controller  39 . In this manner, the posture of working implement  2  may be detected based on an operation instruction signal. 
     Controller  39  and working implement electronic control device  26  can communicate with each other by wireless or wired communication means. 
     Working implement operation members  31 L,  31 R and traveling operation members  33 L,  33 R may be electric type levers. In this case, working implement electronic control device  26  generates a control signal in order to operate working implement  2 , revolving body  3 , or traveling device  5  according to the operation of working implement operation members  31 L,  31 R or traveling operation members  33 L,  33 R. Working implement electronic control device  26  outputs the generated control signal to working machine control device  27  and controller  39 . 
     Working control valve  37 W and traveling control valve  37 D of working machine control device  27  are controlled based on the control signal from working implement electronic control device  26 . The hydraulic oil having the flow rate according to the control signal from working implement electronic control device  26  flows out of working control valve  37 W, and is supplied to at least one of boom cylinder  10 , arm cylinder  11 , and bucket cylinder  12 . Consequently, working implement  2  operates. In addition, the hydraulic oil having the flow rate according to the control signal from working implement electronic control device  26  flows out from traveling control valve  37 D and is supplied to hydraulic motor  5   c . Consequently, traveling device  5  operates. 
     Working implement electronic control device  26  includes a working implement-side storage  35  including at least one of a random access memory (RAM) and a read only memory (ROM) and an arithmetic unit  36  such as a central processing unit (CPU). Working implement electronic control device  26  mainly controls the operations of working implement  2  and revolving body  3 . Working implement-side storage  35  stores information such as a computer program controlling working implement  2 . 
     Although working implement electronic control device  26  and controller  39  are separated from each other, the present invention is not limited to such the form. Working implement electronic control device  26  and controller  39  may be integrated without being separated. 
     Retrofitted kit  100   b  is mounted on hydraulic excavator  100  in order to implement display system  101 . Retrofitted kit  100   b  includes working implement posture sensors  18 A,  18 B,  18 C, GNSS antennas  21 ,  22 , inclination angle sensor  24 , display input device  38 , and controller  39 . 
     Controller  39  performs various functions of display system  101 . Controller  39  includes a storage  43  and a processing unit  44 . Storage  43  includes at least one of the RAM and the ROM. Processing unit  44  includes the CPU and the like. 
     Storage  43  stores working implement data. Working implement data includes a length L 1  of boom  6 , a length L 2  of arm  7 , a length L 3  of bucket  8 , and the like. When bucket  8  is replaced, a value corresponding to the size of replaced bucket  8  is input from input unit  41  and stored in storage  43  as length L 3  of bucket  8  for working implement data. 
     The working implement data includes the minimum value and the maximum value of each of inclination angle θ1 of boom  6 , inclination angle θ2 of arm  7 , and inclination angle θ3 of bucket  8 . Storage  43  stores an image display computer program (hereinafter, referred to as an “image display program”), information about the coordinates of the machine body coordinate system, and the like. 
     The image display program may not be stored in storage  43  but may be stored in server  40 . For example, server  40  is connected to controller  39  through the Internet line. In this case, in response to a request from the operator who operates hydraulic excavator  100 , controller  39  accesses server  40  to execute the image display program stored in server  40 . Then, the image as a result of the execution is displayed on a display  42  through the Internet line. 
     GNSS correction information may be transmitted from server  40  to controller  39  through the Internet line. Furthermore, a construction history by hydraulic excavator  100  may be transmitted from controller  39  to server  40  through the Internet line. 
     Storage  43  stores previously-prepared target construction topography data. The target construction topography data is information about the shape and position of the three-dimensional target construction topography. 
     As illustrated in  FIG.  5   , the target construction topography indicates a target shape of the ground that becomes a working target. The target construction topography is constructed with a plurality of design surfaces  71  each of which is represented by a triangular polygon. 
     The working target is at least one of design surfaces  71 . The operator selects at least one of design surfaces  71  as a target topography  70 . Target topography  70  is a surface to be excavated from among the plurality of design surfaces  71 . Target topography  70  indicates the target shape of a working target. 
     As illustrated in  FIG.  4   , processing unit  44  reads and executes the image display program stored in storage  43  or server  40 . Thus, processing unit  44  causes display  42  to display the support screen. The support screen includes information about the positional relationship between bucket  8  being excavated and target topography  70 . In addition, the support screen includes posture information about bucket  8  in order to support the operation of bucket  8  that is operated by the operator of hydraulic excavator  100 . 
     Controller  39  acquires two reference position data P 1 , P 2  (a plurality of pieces of reference position data) represented in the global coordinate system from GNSS antennas  21 ,  22 . Controller  39  generates revolving body disposition data indicating the disposition of revolving body  3  based on two reference position data P 1 , P 2 . 
     Revolving body disposition data includes one reference position data P of two reference position data P 1 , P 2  and revolving body orientation data Q generated based on two reference position data P 1 , P 2 . In revolving body orientation data Q, an orientation determined from reference position data P acquired by GNSS antennas  21 ,  22  is determined based on an angle relative to a reference orientation (for example, north) of a global coordinate. 
     Revolving body orientation data Q indicates the direction on which revolving body  3  faces (the orientation to which working implement  2  faces). Controller  39  updates the revolving body disposition data, namely, reference position data P and revolving body orientation data Q each time two reference position data P 1 , P 2  are acquired from GNSS antennas  21 ,  22  at a frequency of, for example, 10 Hz. 
     Controller  39  acquires detection information about boom  6 , arm  7 , and bucket  8  from IMUS  18 A,  18 B,  18 C. Controller  39  calculates the attitude of working implement  2  based on the detection information about IMUS  18 A,  18 B,  18 C. Specifically, controller  39  calculates inclination angle θ1 of boom  6  based on the detection information about IMU  18 A, calculates inclination angle θ2 of arm  7  based on the detection information about IMU  18 B, and calculates inclination angle θ3 of bucket  8  based on the detection information about IMU  18 C. 
     When hydraulic sensors  37 SBM,  37 SBK,  37 SAM are used as the working implement posture sensors, working implement posture sensors  18 A,  18 B,  18 C may be omitted from retrofitted kit  100   b . When hydraulic sensors  37 SBM,  37 SBK,  37 SAM are used as the working implement posture sensors, processing unit  44  of controller  39  calculates inclination angles θ1, θ2, θ3 based on the electric signals indicating the magnitudes of the pilot pressures detected by hydraulic sensors  37 SBM,  37 SBK,  37 SAM. 
     Controller  39  acquires inclination information about machine body  1  from inclination angle sensor  24 . As illustrated in  FIG.  3   , the inclination information is an inclination angle θ4 of the width direction of machine body  1  with respect to vertical direction Ng. 
     As described above, processing unit  44  of controller  39  can calculate the relative position of hydraulic excavator  100  with respect to the target topography and the posture of working implement  2 . Thus, processing unit  44  can display information about the positional relationship between bucket  8  being excavated and the target topography, posture information guiding the operator to the operation of bucket  8 , and the like on display  42 . 
     Display input device  38  includes input unit  41 , display  42 , and storage  45 . For example, input unit  41  is a button, a keyboard, a touch panel, or a combination thereof. 
     For example, display  42  is a liquid crystal display (LCD) or an organic electro luminescence (EL) display. For example, storage  45  stores an application (software) reading and executing the image display program. 
     Display input device  38  is connected to controller  39  in a wireless or wired manner. Display input device  38  and controller  39  are wirelessly connected by, for example, Wi-Fi (registered trademark), BLUETOOTH (registered trademark), or Wi-SUN (registered trademark). 
     Display input device  38  may not be included in the above-described retrofitted kit. In this case, the user may substitute an own information portable terminal (smartphone, tablet, personal computer, and the like) as display input device  38 . In addition, a display device existing in hydraulic excavator  100  may be substituted as display input device  38 . 
     Display input device  38  displays the support screen providing information to the operator in order to perform the excavation using working implement  2 . Also, various keys are displayed on the support screen. The operator can perform various functions of display system  101  by touching various keys on the support screen. The support screen will be described later. 
     &lt;Support Screen&gt; 
     With reference to  FIGS.  6  to  8   , first to third examples of the support screen displayed on display  42  in the display system of the embodiment will be described below. 
       FIG.  6    is a view illustrating an image in which a support image is displayed with the bucket as a center in the side view of the hydraulic excavator as the first example of the support screen displayed on the display unit.  FIG.  7    is a view illustrating the image at a viewpoint of the bucket and the target topography viewed from the operator who operates the hydraulic excavator as the second example of the support screen displayed on the display unit.  FIG.  8    is a view illustrating the image in which the support image is displayed with a vehicle body as the center in the side view of the hydraulic excavator as the third example of the support screen displayed on the display unit. 
     As illustrated in  FIG.  6   , the first example of the support screen includes a working machine image  100 G, an image  79  of the target construction topography, and a support image  50 . Working machine image  100 G is an image of the working machine viewed from the side face (an image viewed from the side face of the working machine). Working machine image  100 G includes an image  8 G of the bucket (excavation tool). Image  79  of the target construction topography includes target topography  70 . 
     Support image  50  includes a first  FIG.  51   , a second  FIG.  52   , and a third  FIG.  53   . First  FIG.  51    indicates the inclination of a part of bucket  8 . For example, first  FIG.  51    is a figure indicating the inclination of a bottom surface  8 BT of the bucket. First  FIG.  51    is located on a virtual straight line along bottom surface  8 BT of the bucket in side view. 
     For example, first  FIG.  51    is both or one of a straight line  51   a  and a  FIG.  51   b    having a home base shape (pentagonal shape). Straight line  51   a  is a straight line that passes through bottom surface  8 BT of the bucket and is superimposed on a virtual straight line along bottom surface  8 BT of the bucket. A corner  51   bt  in  FIG.  51   b    having the home base shape is located on a virtual straight line passing through bottom surface  8 BT of the bucket and along bottom surface  8 BT of the bucket.  FIG.  51   b    may have a polygonal shape such as a triangle or a circular shape such as a circle or an ellipse as long as the inclination of bottom surface  8 BT of the bucket can be specified. 
     Second  FIG.  52    indicates the inclination of target topography  70 . For example, second  FIG.  52    is both or one of a straight line  52   a  and a triangular  FIG.  52   b   . Straight line  52   a  is a straight line superimposed on a virtual straight line parallel to target topography  70 . A corner  52   bt  in triangular  FIG.  52   b    is located on a virtual straight line parallel to target topography  70 .  FIG.  52   b    may have a polygonal shape other than the triangle or the circular shape such as the circle or the ellipse as long as the inclination of target topography  70  can be specified. 
     Third  FIG.  53    is a hatched region in the drawing. Third  FIG.  53    is a figure representing a relative relationship between first  FIG.  51    and second  FIG.  52   . For example, third  FIG.  53    is a figure connecting first  FIG.  51    and second  FIG.  52   . Third  FIG.  53    continuously connects first  FIG.  51    and second  FIG.  52    without interruption. For example, third  FIG.  53    extends in a band shape and connects first  FIG.  51    and second  FIG.  52   . 
     A virtual straight line (first straight line) along the inclination indicated by first  FIG.  51    and a virtual straight line (second straight line) along the inclination indicated by second  FIG.  52    pass through the same fixed point coordinate on display  42 . For example, both the virtual straight line along the inclination indicated by first  FIG.  51    and the virtual straight line along the inclination indicated by second  FIG.  52    pass through blade edge  8 TG of bucket image  8 G (meaning the image of blade edge  8 T on the screen) in side view. 
     For example, support image  50  includes an annular image  50 C centered on a predetermined portion in the support screen. Annular image  50 C included in support image  50  is along the circumference centered on, for example, blade edge  8 TG (predetermined portion) of bucket image  8 G in side view as the predetermined portion. 
     Annular image  50 C is an image in which a long belt is bent and rounded. Straight line  51   a  of first  FIG.  51    and straight line  52   a  of second  FIG.  52    are illustrated in the belt of annular image  50 C. Each of straight line  51   a  and straight line  52   a  extends in the radial direction of the annular ring included in support image  50 . Corner  51   bt  of  FIG.  51   b    having the home base shape and corner  52   bt  of triangular  FIG.  52   b    are positioned in the belt of annular image  50 C. Third  FIG.  53    is illustrated in the belt of annular image  50 C. Third  FIG.  53    has a belt-like arc shape connecting first  FIG.  51    and second  FIG.  52   . 
     Two first  FIGS.  51    and two second  FIGS.  52    are illustrated In the belt of annular image  50 C. Two first  FIGS.  51    face each other across the center (blade edge  8 TG) of annular image  50 C. Two second  FIGS.  52    face each other across the center (blade edge  8 TG) of annular image  50 C. 
     The annular ring included in support image  50  is illustrated so as to surround the periphery of bucket image  8 G. In this case, the circle on the inner peripheral side constituting the belt-like annular ring is illustrated on the outer peripheral side of bucket image  8 G so as not to overlap bucket image  8 G. 
     A scale may be illustrated in the belt of annular image  50 C included in support image  50 . The scale extends in the radial direction in the belt of annular image  50 C. The arc-shaped portion in third  FIG.  53    is colored differently from other portions in the belt of annular image  50 C. For example, the color of the arc shape in third  FIG.  53    is red, and the color of other portions in the belt of the circular ring is a color other than red, for example, black. 
     When the actual posture of bucket  8  changes due to the excavation, the posture of bucket image  8 G in support image  50  also changes according to the actual posture of bucket  8 . When the inclination of bottom surface  8 BT of the bucket changes due to the posture change of bucket image  8 G, the position of first  FIG.  51    changes according to the change in the inclination. Specifically, first  FIG.  51    moves in the circumferential direction in the belt of annular image  50 C. 
     The operator can check the inclination of bucket  8  with respect to target topography  70  in real time by visually recognizing support image  50 . Thus, the inclination angle of bucket  8  can be appropriately operated at the time of excavating target topography  70 . 
     As illustrated in  FIG.  7   , the second example of the support screen includes bucket image  8 G, image  79  of the target construction topography, and a support image  60 . Bucket image  8 G and image  79  of the target construction topography are images at a viewpoint (operator&#39;s view) from which the operator seated on the driver&#39;s seat  4 S ( FIG.  1   ) looks at bucket  8 . Image  79  of the target construction topography includes target topography  70 . 
     Support image  60  includes a first  FIG.  61   , a second  FIG.  62   , and a third  FIG.  63   . First  FIG.  61    indicates the inclination of a part of bucket  8 . For example, first  FIG.  61    is a figure indicating the inclination in the direction in which blade edges  8 TG of the bucket are arranged. First  FIG.  61    is located on the virtual straight line along the direction in which blade edges  8 TG of the bucket are arranged in operator view. 
     For example, first  FIG.  61    is both or one of a straight line  61   a  and a  FIG.  61   b    having the home base shape (pentagonal shape). Straight line  61   a  is a straight line superimposed on a virtual straight line passing through the plurality of blade edges  8 TG. A corner  61   bt  of  FIG.  61   b    having the home base shape is positioned on the virtual straight line passing through the plurality of blade edges  8 TG.  FIG.  61   b    may have a polygonal shape such as a triangle or a circular shape such as a circle or an ellipse as long as the inclination of the plurality of blade edges  8 TG of the bucket can be specified. 
     Second  FIG.  62    indicates the inclination of target topography  70 . For example, second  FIG.  62    is both or one of a straight line  62   a  and a triangular  FIG.  62   b   . Straight line  62   a  is a straight line superimposed on a virtual straight line parallel to target topography  70 . A corner  62   bt  of triangular  FIG.  62   b    is located on a virtual straight line parallel to target topography  70 .  FIG.  62   b    may have a polygonal shape other than the triangle or the circular shape such as the circle or the ellipse as long as the inclination of target topography  70  can be specified. 
     Third  FIG.  63    is a hatched region in the drawing. Third  FIG.  63    is a figure connecting first  FIG.  61    and second  FIG.  62   . Third  FIG.  63    continuously connects first  FIG.  61    and second  FIG.  62    without interruption. For example, third  FIG.  63    extends in a belt shape and connects first  FIG.  61    and second  FIG.  62   . 
     A virtual straight line (first straight line) along the inclination indicated by first  FIG.  61    and a virtual straight line (second straight line) along the inclination indicated by second  FIG.  62    pass through the same fixed point coordinate on display  42 . For example, both the virtual straight line along the inclination indicated by first  FIG.  61    and the virtual straight line along the inclination indicated by second  FIG.  62    pass through a center  8 TC in the width direction of the plurality of blade edges  8 TG as viewed from the operator. 
     For example, support image  60  includes a belt-shaped arc image  60 C centered on a predetermined portion in the support screen. Belt-shaped arc image  60 C included in support image  60  is along the circumference centered on center  8 TC (predetermined portion) in the width direction of the plurality of blade edges  8 TG as viewed from, for example, the operator as the predetermined portion. 
     Straight line  61   a  of first  FIG.  61    and straight line  62   a  of second  FIG.  62    are illustrated in the belt of arc image  60 C. Each of straight line  61   a  and straight line  62   a  extends in the radial direction of arc image  60 C. Corner  61   bt  of  FIG.  61   b    having the home base shape and corner  62   bt  of triangular  FIG.  62   b    are positioned in the belt of arc image  60 C. Third  FIG.  63    is illustrated in the belt of arc image  60 C. Third  FIG.  63    has a belt-like arc shape connecting first  FIG.  61    and second  FIG.  62   . 
     Two arc images  60 C are illustrated. Each of two arc images  60 C is an arc centered on center  8 TC in the width direction of the plurality of blade edges  8 TG. One first  FIG.  61    and one second  FIG.  62    are illustrated in the belt of one arc image  60 C. Two first  FIGS.  61    face each other across center  8 TC in the width direction of the plurality of blade edges  8 TG. Two second  FIGS.  62    face each other across center  8 TC in the width direction of the plurality of blade edges  8 TG. 
     Two arc images  60 C are illustrated so as to surround the periphery of bucket image  8 G. In this case, the arc on the inner peripheral side constituting each of two arc images  60 C is illustrated on the outer peripheral side of bucket image  8 G so as not to overlap bucket image  8 G. 
     A scale may be illustrated in each belt of two arc images  60 C. The scale extends in the radial direction in the belt of arc image  60 C. The portion of the arc shape in third  FIG.  63    is colored differently from other portions in the belt of arc image  60 C. For example, the color of the arc shape in third  FIG.  63    is red, and the color of other portions in the belt of arc image  60 C is a color other than red, for example, black. 
     When the actual posture of bucket  8  changes due to the excavation, the posture of bucket image  8 G in support image  60  also changes according to the actual posture of bucket  8 . When the inclination in the direction in which the plurality of blade edges  8 TG are arranged changes due to the posture change of bucket image  8 G, the position of first  FIG.  61    changes according to the change in the inclination. Specifically, first  FIG.  61    moves in the circumferential direction within the belt of arc image  60 C. 
     The operator can check the inclination of bucket  8  with respect to target topography  70  in real time by visually recognizing support image  60 . Thus, the inclination angle of bucket  8  can be appropriately operated at the time of excavating target topography  70 . 
     As illustrated in  FIG.  8   , the third example of the support screen includes working machine image  100 G, image  79  of the target construction topography, and support image  50 . Working machine image  100 G is an image of the working machine viewed from the side face (an image viewed from the side face of the working machine). Working machine image  100 G includes image  1 G of the machine body and image  2 G of the working implement. Image  79  of the target construction topography includes target topography  70 . 
     Support image  50  is the same image as support image  50  in  FIG.  6   . A virtual straight line (first straight line) along the inclination indicated by first  FIG.  51    and a virtual straight line (second straight line) along the inclination indicated by second  FIG.  52    pass through the same fixed point coordinate on display  42 . For example, both the virtual straight line along the inclination indicated by first  FIG.  51    and the virtual straight line along the inclination indicated by second  FIG.  52    pass through a predetermined portion of the working machine in side view. 
     For example, support image  50  includes annular image  50 C centered on a predetermined portion in the support screen. Annular image  50 C included in support image  50  is along the circumference centered on the center (predetermined portion) of machine body image  1 G, for example, in side view as the predetermined portion. 
     Annular image  50 C included in support image  50  is illustrated so as to surround the periphery of machine body image  1 G. In this case, the circle on the inner peripheral side constituting annular image  50 C is illustrated on the outer peripheral side of machine body image  1 G so as not to overlap machine body image  1 G. 
     When the actual posture of bucket  8  changes due to the excavation, the posture of bucket image  8 G in support image  50  also changes according to the actual posture of bucket  8 . When the inclination of bottom surface  8 BT of the bucket changes due to the posture change of bucket image  8 G, the position of first  FIG.  51    changes according to the change in the inclination. Specifically, first  FIG.  51    moves in the circumferential direction in the belt of annular image  50 C. 
     The operator can check the inclination of bucket  8  with respect to target topography  70  in real time by visually recognizing support image  50 . Thus, the inclination angle of bucket  8  can be appropriately operated at the time of excavating target topography  70 . 
     The operator can switch the support screen display in  FIGS.  6 ,  7 , and  8    by the switching operation of the support screen. 
     In the above description, annular image  50 C is not limited to the annular shape, but may be a polygonal shape such as a triangle or a circular shape such as a circle or an ellipse. 
     &lt;Method for Generating Support Image&gt; 
     With reference to  FIGS.  4  and  9  to  11   , a method for generating the first example and the second example of the support screen of the embodiment will be described below. 
       FIGS.  9 (A) to  9 (E)  illustrate the method for generating the support image in order of steps.  FIGS.  10 (A) to  10 (E)  illustrate the method for generating the support image in side view of the hydraulic excavator in the order of steps subsequent to the steps of  FIG.  9   .  FIGS.  11 (A) to  11 (E)  are diagrams illustrating the method for generating the support image at the viewpoint of viewing the bucket and the target topography from the operator who operates the hydraulic excavator in the order of steps subsequent to the steps of  FIG.  9   . 
       FIGS.  9 (A) to  9 (E)  illustrate viewpoints when the Xa-Ya plane is viewed from the Za-axis direction, where the horizontal axis is the Xa-axis and the vertical axis is the Ya-axis. 
     As illustrated in  FIG.  4   , processing unit  44  of controller  39  reads and executes the image display program stored in storage  43  or server  40 , generates the support screen, and displays the support screen on display  42 . The reason is as follows. 
     As illustrated in  FIG.  9 (A) , processing unit  44  of controller  39  acquires two reference position data P 1 , P 2  (a plurality of reference position data) represented in the global coordinate system from GNSS antennas  21 ,  22 . Processing unit  44  of controller  39  determines the position in the coordinate system based on one reference position data P of two reference position data P 1 , P 2 . Thereafter, processing unit  44  of controller  39  determines which direction the line connecting the coordinates of two reference position data P 1 , P 2  is directed with respect to the reference orientation (for example, north) of the global coordinate. 
     As illustrated in  FIG.  9 (B) , processing unit  44  of controller  39  positions the target construction topography with respect to reference position data P 1 , P 2  in the coordinate system based on the reference position data and the determined orientation. At this time, processing unit  44  of controller  39  acquires the previously-produced target construction topography data from storage  43  or server  40 , and collates the shape and coordinates of the three-dimensional target construction topography included in the target construction topography data with the coordinates of reference position data P 1 , P 2 . 
     As illustrated in  FIG.  9 (C) , processing unit  44  of controller  39  determines a direction DW of the operation plane of working implement  2  based on two reference position data P 1 , P 2 . 
     As illustrated in  FIG.  9 (D) , processing unit  44  of controller  39  determines the posture of working implement  2 . At this point, processing unit  44  of controller  39  acquires the postures of boom  6 ,  18 A arm  7 , and bucket  8  from working implement posture sensors  18 A,  18 B,  18 C. Alternatively, processing unit  44  of controller  39  acquires electric signals of hydraulic sensors  37 SBM,  37 SBK,  37 SAM through working implement electronic control device  26 . Processing unit  44  of controller  39  calculates the posture (θ1, θ2, θ3) of working implement  2  based on the acquired information, and determines a position LB 1  of boom  6 , a position LB 2  of arm  7 , and a position LA of bucket  8 . 
     As illustrated in  FIG.  9 (E) , processing unit  44  of controller  39  disposes a 3D (dimension) model of hydraulic excavator  100  based on reference position data P 1 , P 2  determined above, direction DW of the operation plane of working implement  2 , the posture ( 01 ,  02 ,  03 ) of working implement  2 , and the like. At this point, processing unit  44  of controller  39  acquires the 3D model of hydraulic excavator  100  stored in storage  43  or server  40 . 
     As illustrated in  FIG.  10 (A) , processing unit  44  of controller  39  produces working machine image  100 G in side view based on the 3D model obtained in  FIG.  9 (E) . In addition, processing unit  44  of controller  39  produces image  79  of the target construction topography in side view. As illustrated in  FIG.  5   , image  79  of the target construction topography is obtained by calculating an intersection line  80  between a plane  77  passing through the current position of blade edge  8 T of bucket  8  and design surface  71 . 
     As illustrated in  FIG.  10 (B) , processing unit  44  of controller  39  generates annular image  50 C centered on a predetermined position (for example, blade edge  8 TG) in bucket image  8 G in side view. Annular image  50 C is generated so as to surround the periphery of bucket image  8 G. 
     As illustrated in  FIG.  10 (C) , processing unit  44  of controller  39  generates first  FIG.  51    indicating the inclination of a part (for example, bottom surface  8 BT) of bucket image  8 G in the side view. First  FIG.  51    is located on a virtual straight line  51 L (first straight line) passing through bottom surface  8 BT of the bucket and along bottom surface  8 BT of the bucket in side view. 
     For example, first  FIG.  51    is both or one of a straight line  51   a  and a  FIG.  51   b    having a home base shape (pentagonal shape). Straight line  51   a  is a straight line superimposed on straight line  51 L. Corner  51   bt  of  FIG.  51   b    having the home base shape is located on straight line  51 L. 
     As illustrated in  FIG.  10 (D) , processing unit  44  of controller  39  generates second  FIG.  52    indicating the inclination of target topography  70  in side view. Second  FIG.  52    is located on a virtual straight line  52 L (second straight line) parallel to target topography  70  in side view. 
     For example, second  FIG.  52    is both or one of a straight line  52   a  and a triangular  FIG.  52   b   . Straight line  52   a  is a straight line superimposed on straight line  52 L. Corner  52   bt  of triangular  FIG.  52   b    is located on straight line  52 L. 
     Straight line  51 L and straight line  52 L are set so as to pass through the same point coordinate fixed on display  42 . For example, straight line  51 L and straight line  52 L are set so as to pass through the same point (blade edge  8 TG) in side view. 
     As illustrated in  FIG.  10 (E) , processing unit  44  of controller  39  generates third  FIG.  53    connecting first  FIG.  51    and second  FIG.  52    in side view. Third  FIG.  53    continuously connects first  FIG.  51    and second  FIG.  52    without interruption. For example, third  FIG.  53    extends in a band shape and connects first  FIG.  51    and second  FIG.  52   . 
     For example, third  FIG.  53    is generated as the arc portion in the belt in annular image  50 C. For example, third  FIG.  53    is generated in a color different from other arc portions in the belt in annular image  50 C. 
     When the actual posture of bucket  8  changes due to the excavation, the posture of bucket image  8 G in the support image also changes according to the actual posture of bucket  8 . When the inclination of bottom surface  8 BT of the bucket changes due to the posture change of bucket image  8 G, the position of first  FIG.  51    changes according to the change in the inclination. Specifically, first  FIG.  51    moves in the circumferential direction in the annular belt. Thus, the circumferential length of third  FIG.  53    having the arc shape changes. 
     As illustrated in  FIG.  11 (A) , processing unit  44  of controller  39  produces bucket image  8 G in operator&#39;s view based on the 3D model obtained in  FIG.  9 (E) . In addition, processing unit  44  of controller  39  produces image  79  of the target construction topography in operator&#39;s view. 
     As illustrated in  FIG.  11 (B) , processing unit  44  of controller  39  generates image  60 C of an arc centered on a predetermined position (for example, center  8 TC in the width direction of the plurality of blade edges  8 TG) in bucket image  8 G in operator&#39;s view. Arc image  60 C is generated so as to surround the periphery of bucket image  8 G. Specifically, two arc images  60 C are generated so as to sandwich bucket image  8 G from the left and right directions. 
     As illustrated in  FIG.  11 (C) , processing unit  44  of controller  39  generates first  FIG.  61    indicating the inclination of a part of bucket image  8 G (for example, the direction in which the plurality of blade edges  8 TG are arranged) in operator&#39;s view. First  FIG.  61    is positioned on a virtual straight line  61 L (first straight line) passing through the plurality of blade edges  8 TG in operator&#39;s view. 
     For example, first  FIG.  61    is both or one of a straight line  61   a  and a  FIG.  61   b    having the home base shape (pentagonal shape). Straight line  61   a  is a straight line superimposed on straight line  61 L. Corner  61   bt  of  FIG.  61   b    having the home base shape is located on straight line  51 L. 
     As illustrated in  FIG.  11 (D) , processing unit  44  of controller  39  generates second  FIG.  62    indicating the inclination of target topography  70  in operator&#39;s view. Second  FIG.  62    is located on a virtual straight line  62 L (second straight line) parallel to target topography  70  in operator&#39;s view. 
     For example, second  FIG.  62    is both or one of a straight line  62   a  and a triangular  FIG.  62   b   . Straight line  62   a  is a straight line superimposed on straight line  62 L. Corner  62   bt  of triangular  FIG.  62   b    is located on straight line  62 L. 
     Straight line  61 L and straight line  62 L are set so as to pass through the same point coordinate fixed on display  42 . For example, straight line  61 L and straight line  62 L are set to pass through the same point (center  8 TC in the width direction of the number of blade edges  8 TG) in operator&#39;s view. 
     As illustrated in  FIG.  11 (E) , processing unit  44  of controller  39  generates third  FIG.  63    connecting first  FIG.  61    and second  FIG.  62    in operator&#39;s view. Third  FIG.  63    continuously connects first  FIG.  61    and second  FIG.  62    without interruption. For example, third  FIG.  63    extends in a belt shape and connects first  FIG.  61    and second  FIG.  62   . 
     For example, third  FIG.  63    is generated as the arc portion in the belt in arc image  60 C. For example, third  FIG.  63    is generated in a color different from that of other arc portions in the belt in arc image  60 C. 
     When the actual posture of bucket  8  changes due to the excavation, the posture of bucket image  8 G in support image  60  also changes according to the actual posture of bucket  8 . When the inclination in the direction in which the plurality of blade edges  8 TG are arranged changes due to the posture change of bucket image  8 G, the position of first  FIG.  61    changes according to the change in the inclination. Specifically, first  FIG.  61    moves in the circumferential direction within the belt of arc image  60 C. Thus, the circumferential length of third  FIG.  63    having the arc shape changes. 
     &lt;Method for Controlling Display System&gt; 
     With reference to  FIG.  12   , a method for controlling the display system of the embodiment will be described below. 
       FIG.  12    is a flowchart illustrating the method for controlling the display system of the embodiment. As illustrated in  FIG.  12   , processing unit  44  of controller  39  generates first  FIG.  51  or  61    indicating the inclination of a part of bucket  8  (step S 1 ). Processing unit  44  of controller  39  generates first  FIG.  51    as described with reference to  FIG.  10 (C) . In addition, processing unit  44  of controller  39  generates first  FIG.  61    as described with reference to  FIG.  11 (C) . 
     Processing unit  44  of controller  39  generates second  FIG.  52  or  62    indicating the inclination of target topography  70  (step S 2 ). Processing unit  44  of controller  39  generates second  FIG.  52    as described with reference to  FIG.  10 (D) . In addition, processing unit  44  of controller  39  generates second  FIG.  62    as described with reference to  FIG.  11 (D) . 
     Processing unit  44  of controller  39  generates third  FIG.  53    connecting first  FIG.  51    and second  FIG.  52    or third  FIG.  63    connecting first  FIG.  61    and second  FIG.  62    (step S 3 ). Processing unit  44  of controller  39  generates third  FIG.  53    as described with reference to  FIG.  10 (E) . In addition, processing unit  44  of controller  39  generates third  FIG.  63    as described with reference to  FIG.  11 (E) . 
     Processing unit  44  of controller  39  displays support image  50  including first  FIG.  51   , second  FIG.  52   , and third  FIG.  53    or support image  60  including first  FIG.  61   , second  FIG.  62   , and third  FIG.  63    on display  42  (step S 4 ). As illustrated in  FIG.  6  or  8   , processing unit  44  of controller  39  displays support image  50  on display  42  together with bucket image  8 G, image  79  of the target construction topography, and the like. Processing unit  44  of controller  39  switches between the display in  FIG.  6    and the display in  FIG.  8    based on the switching operation of the support screen by the operator. 
     As illustrated in  FIG.  7   , processing unit  44  of controller  39  displays support image  60  on display  42  together with bucket image  8 G, image  79  of the target construction topography, and the like. Processing unit  44  of controller  39  switches the display in  FIG.  6   , the display in  FIG.  7   , and the display in  FIG.  8    based on the switching operation of the support screen by the operator. 
     On the support screen, only third  FIGS.  53 ,  63    may be displayed as support images  50  or  60 , and first  FIGS.  51 ,  61    and second  FIGS.  52 ,  62    may not be displayed. 
     &lt;Modifications&gt; 
     With reference to  FIGS.  13  and  14   , a modification of the display system of the embodiment will be described below. 
       FIG.  13    is a view illustrating the image in which the support image indicating an extension line of a bucket bottom surface is displayed in side view of the hydraulic excavator as the modification of the support screen displayed on the display unit.  FIG.  14    is a view illustrating a tilt bucket. 
     As illustrated in  FIG.  13   , the modification of the support screen includes working machine image  100 G, image  79  (second figure) of the target construction topography, and a support image  91  (first figure). Working machine image  100 G is an image of the working machine in side view. Working machine image  100 G includes an image  8 G of the bucket (excavation tool). Image  79  of the target construction topography includes target topography  70 . 
     Image  79  of the target construction topography indicates the inclination of the target topography. Support image  91  is a straight line extending along bottom surface  8 BT of the bucket and extending from bottom surface  8 BT of the bucket. A straight line constituting support image  91  preferably intersects with a straight line that is image  79  of the target construction topography and indicates the inclination of the target topography. 
     When the actual posture of bucket  8  changes due to the excavation, the posture of bucket image  8 G on the support screen also changes according to the actual posture of bucket  8 . When the inclination of bottom surface  8 BT of the bucket changes due to the posture change of bucket image  8 G, the position and inclination of support image  91  changes according to the change in the inclination. In this modification, support image  91  and image  79  of the target construction topography become support displays for supporting the operation of the operator. 
     The operator can check the inclination of bucket  8  with respect to target topography  70  in real time by visually recognizing support image  91 . Thus, the inclination angle of bucket  8  can be appropriately operated at the time of excavating target topography  70 . 
     Processing unit  44  of controller  39  displays the support screen in  FIG.  13    on display  42  of display input device  38 . 
     As illustrated in  FIG.  14   , tilt bucket  8  may be used as excavation tool  8  used in working machine  100 . Tilt bucket  8  is attached to a coupling member  8 C through a rotation shaft (tilt pin)  8 R. Coupling member  8 C is attached to the distal end of arm  7  through bucket pin  15 . Rotation shaft  8 R extends in the direction orthogonal to the extending direction of bucket pin  15 . Tilt bucket  8  is swingable in an arrow direction in the drawing with respect to the operation plane of working implement  2  by rotating around rotation shaft  8 R. 
     &lt;Effects&gt; 
     An advantageous effect of the embodiment will be described below. 
     According to the embodiment, as illustrated in  FIGS.  6  and  8   , third  FIG.  53    connecting first  FIG.  51    indicating the inclination of a part of bucket  8  and second  FIG.  52    indicating the inclination of target topography  70  is displayed by processing unit  44  of controller  39 . When the actual posture of bucket  8  changes due to the excavation, the inclination of first  FIG.  51    with respect to second  FIG.  52    changes, and accordingly third  FIG.  53    changes. Thus, the operator can more easily and visually understand the positional relationship between target topography  70  and bucket  8 . Furthermore, the operator can check the inclination of bucket  8  with respect to target topography  70  in real time by visually checking the change of third  FIG.  53    on display  42 . Thus, the inclination angle of bucket  8  can be appropriately operated at the time of excavating target topography  70 . 
     According to the embodiment, as illustrated in  FIG.  7   , third  FIG.  63    connecting first  FIG.  61    indicating the inclination of a part of bucket  8  and second  FIG.  62    indicating the inclination of target topography  70  is displayed by processing unit  44  of controller  39 . Thus, similarly to  FIGS.  6  and  8   , the operator can more easily visually understand the positional relationship between the target topography  70  and the bucket  8 . In addition, the inclination angle of bucket  8  can be appropriately operated during the excavation so as to achieve target topography  70 . 
     According to the embodiment, as illustrated in  FIGS.  6  and  8   , processing unit  44  of controller  39  sets the figure indicating the inclination of bottom surface  8 BT of bucket  8  to first  FIG.  51   . Thus, the inclination of bucket  8  can be easily and visually understood in side view. 
     According to the embodiment, as illustrated in  FIG.  7   , processing unit  44  of controller  39  sets the figure indicating the inclination of blade edge  8 TG of bucket  8  (inclination in the direction in which the plurality of blade edges  8 TG are arranged) to first  FIG.  51   . Thus, the inclination of bucket  8  can be easily and visually understood in operator&#39;s view. 
     According to the embodiment, as illustrated in  FIGS.  10 (D) and  11 (D) , processing unit  44  of controller  39  sets first straight lines  51 L,  61 L and second straight lines  52 L,  62 L so as to pass through fixed point coordinates on display  42 . Thus, third  FIGS.  53 ,  63    are displayed at the fixed positions on display  42 . For this reason, third  FIGS.  53 ,  63    are prevented from moving out of the display range by moving in display  42 . 
     According to the embodiment, as illustrated in  FIGS.  6  to  8   , processing unit  44  of controller  39  displays third  FIGS.  53 ,  63    on display  42  along a circle centered on a predetermined portion. Thus, third  FIGS.  53 ,  63    change along the circle. For this reason, the operator can easily recognize the change in third  FIGS.  53 ,  63   . 
     According to the embodiment, as illustrated in  FIG.  6   , processing unit  44  of controller  39  displays bucket image  8 G and displays, as a predetermined portion, third  FIG.  53    on display  42  along the circle centered on a predetermined portion of bucket image  8 G. Thus, the operator can always view the periphery of the working target of display  42  without moving the line of sight. 
     According to the embodiment, as illustrated in  FIG.  6   , processing unit  44  of controller  39  displays the circle so as to surround the periphery of bucket image  8 G. Thus, the operator can always view the periphery of the working target of display  42  without moving the line of sight. 
     According to the embodiment, as illustrated in  FIG.  8   , processing unit  44  of controller  39  displays working machine image  100 G and displays, as a predetermined portion, third  FIG.  53    on display  42  along a circle centered on a predetermined portion of working machine image  100 G. Thus, the operator easily grasps the entire work situation. 
     According to the embodiment, as illustrated in  FIG.  8   , processing unit  44  of controller  39  displays, as a predetermined portion in working machine image  100 G, third  FIG.  53    on display  42  along a circle centered on machine body image  1 G of the working machine. Thus, the operator easily grasps the entire work situation. 
     According to the embodiment, as illustrated in  FIG.  8   , processing unit  44  of controller  39  displays a circle so as to surround machine body image  1 G. Thus, the operator easily grasps the entire work situation. 
     According to the embodiment, as illustrated in  FIGS.  6  and  8   , processing unit  44  of controller  39  can select, as the center of the circle, a portion from among a plurality of options including the predetermined portion of bucket image  8 G and the predetermined portion of working machine image  100 G. Thus, the center of the circle can be switched between the predetermined portion of bucket image  8 G and the predetermined portion of working machine image  100 G. For this reason, when the predetermined portion of bucket image  8 G is set to the center of the circle, the periphery of the work target of display  42  can be always viewed without moving the line of sight. When the predetermined portion of working machine image  100 G is set to the center of the circle, the entire work situation can be easily grasped. 
     In addition, according to the embodiment, as illustrated in  FIG.  13   , processing unit  44  of controller  39  displays the first figure that is straight line  91  extended from bottom surface  8 BT of bucket  8  in side view of bucket  8  and the second figure indicating the inclination of image  79  of the target construction topography. Thus, the operator can easily and visually understand the positional relationship between image  79  of the target construction topography and bucket  8 . 
     It should be considered that the disclosed embodiment is illustrative and non-restrictive in every respect. The scope of the present invention is defined by not the description above, but the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included in the present invention. 
     REFERENCE SIGNS LIST 
       1 : machine body,  1 G: machine body image,  2 : working implement,  2 G: image of working implement,  3 : revolving body,  3 CW: counter weight,  3 EG: machine chamber,  4 : operator cab,  4 S: driver&#39;s seat,  5 : traveling device,  5   a : crawler belt,  5   c : hydraulic motor,  6 : boom,  7 : arm,  8 : bucket,  8 B: blade,  8 C: coupling member,  8 BT: bottom surface,  8 G: bucket image,  8 R: rotation axis,  8 T,  8 TG: blade edge,  8 TC: center,  9 : handrail,  10 : boom cylinder,  11 : arm cylinder,  12 : bucket cylinder,  13 : boom pin,  14 : arm pin,  15 : bucket pin,  16 : pin,  18 A,  18 B,  18 C: working implement posture sensor,  19 : position detector,  21 ,  22 : antenna,  24 : inclination angle sensor,  25 : operation device,  26 : working implement electronic control device,  27 : working machine control device,  31 L,  31 R: working implement operation member,  32 L,  32 R: working implement operation detector,  33 L,  33 R: travel control member,  34 L,  34 R: travel control detector,  35 : working implement-side storage,  36 : arithmetic unit,  37 D: traveling control valve,  37 SAM,  37 SBK,  37 SBM,  37 SRM,  37 S 1   b ,  37 S 1   f ,  37 Srb,  37 Srf: hydraulic sensor,  37 W: working control valve,  38 : display input apparatus,  39 : controller,  40 : server,  41 : input unit,  42 : display,  43 ,  45 : storage,  44 : processing unit,  47 : hydraulic pump,  50 ,  60 ,  91 : support image,  50 C: annular image,  51 ,  61 : first figure,  51   a ,  52   a ,  61   a ,  62   a : straight line,  51 L,  61 L: first straight line,  51   b ,  52   b ,  61   b ,  62   b : figure,  51   bt ,  52   bt ,  61   bt ,  62   bt : corner,  52 ,  62 : second figure,  52 L,  62 L: second straight line,  53 ,  63 : third figure,  60 C: arc image,  70 : target topography,  71 : design surface,  77 : plane,  79 : image of target construction topography,  80 : intersection line,  100 ,  100   a : working machine (hydraulic excavator),  100 G: working machine image,  100   b : retrofitted kit,  101 : display system, AX 1 : center axis, AX 3 : axis, L 1 , L 2 , L 3 : length, LA, LB 1 , LB 2 : position, Ng: vertical direction, P, P 1 , P 2 : reference position data, Q: revolving unit orientation data