System and method for setting the vehicle body coordinate system in a work machine.

Abstract

To set a vehicle body coordinate system with high accuracy in a work machine without turning a first vehicle body.SOLUTION: A system comprises a posture sensor, a position measurement device, and a controller. The posture sensor detects a posture of a first vehicle body. The position measurement device measures a position of a first target portion included in a work machine. The controller acquires a posture of the first vehicle body in a state where the first vehicle body detected by the posture sensor is made stationary relative to the second vehicle body. The controller sets a vehicle body coordinate system based on the posture of the first vehicle body and the position of the first target portion.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a system and method for setting the body coordinate system in a work machine. [Background technology]

[0002] Some construction machines comprise a first vehicle body, a second vehicle body rotatably connected to the first vehicle body, and a work implement movably mounted to the first vehicle body. The construction machine performs construction work such as excavation by rotating the first vehicle body relative to the second vehicle body or by operating the work implement. Conventionally, technologies for detecting the position of a work implement are known. For example, in Patent Document 1, the construction machine is equipped with a position sensor such as GNSS (Global Navigation Satellite System). The position sensor detects the position of the construction machine in the global coordinate system to which the position sensor is attached. The position in the global coordinate system is a coordinate system measured by GNSS, and is a coordinate system based on an origin fixed on the Earth.

[0003] Furthermore, the controller of the work machine calculates the position of the work machine in the vehicle coordinate system from the position of the position sensor. The vehicle coordinate system is a coordinate system based on the work machine. For example, the controller calculates the position of the work machine relative to the position sensor based on the dimensions of each component of the work machine's body, as well as mechanical parameters such as the angle of the work machine. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2012-233353 [Overview of the project] [Problems that the invention aims to solve]

[0005] As described above, in order to accurately calculate the position of the work machine, it is necessary to accurately set the vehicle coordinate system of the work machine. Examples of methods for setting the vehicle coordinate system of a work machine include the following:

[0006] First, a first target prism is attached to the first vehicle body. Then, by rotating the first vehicle body, multiple positions of the first target prism are measured by an external position measuring device. These multiple positions of the first target prism are input to a controller, which calculates the rotation plane of the first vehicle body based on the multiple positions of the first target prism.

[0007] Next, a second target prism is attached to the work implement. Then, by moving the work implement up and down relative to the first vehicle body, multiple positions of the second target prism are measured by an external position measuring device. These multiple positions of the second target prism are input to the controller, which calculates the work implement plane on which the work implement operates based on the multiple positions of the second target prism. Then, based on the rotation plane and the work implement plane, the controller calculates a vehicle coordinate system based on a virtually set origin on the first vehicle body.

[0008] However, in the method for setting the vehicle coordinate system in the above-described work machine, measurement errors during the rotation of the first vehicle body result in errors in the vehicle coordinate system. Rotating the first vehicle body requires a large work area. Furthermore, rotating the first vehicle body increases the number of work steps required. The objective of the present invention is to set the vehicle coordinate system accurately in a work machine without rotating the first vehicle body. [Means for solving the problem]

[0009] A system according to one aspect of the present invention is a system for setting a vehicle coordinate system in a work machine. The work machine comprises a first vehicle body, a second vehicle body rotatably connected to the first vehicle body, and a work machine operably mounted on the first vehicle body. The vehicle coordinate system is a coordinate system based on the first vehicle body. The system comprises an attitude sensor, a position measuring device, and a controller. The attitude sensor detects the attitude of the first vehicle body. The position measuring device measures the position of a first target part included in the work machine. The controller obtains the attitude of the first vehicle body from the attitude sensor when the first vehicle body is stationary relative to the second vehicle body. The controller sets the vehicle coordinate system based on the attitude of the first vehicle body and the position of the first target part.

[0010] Another aspect of the present invention relates to a method for setting a vehicle coordinate system in a work machine. The work machine comprises a first vehicle body, a second vehicle body rotatably connected to the first vehicle body, and a work implement operably mounted to the first vehicle body. The vehicle coordinate system is a coordinate system based on the first vehicle body. The method comprises: obtaining the attitude of the first vehicle body while it is stationary relative to the second vehicle body using an attitude sensor that detects the attitude of the first vehicle body; measuring the position of a first target part included in the work implement; and setting a vehicle coordinate system based on the attitude of the first vehicle body and the position of the first target part. [Effects of the Invention]

[0011] According to the present invention, instead of determining the rotation plane of the first vehicle body, the vehicle body coordinate system is set based on the attitude of the first vehicle body detected by the attitude sensor. Therefore, in the work machine, the vehicle body coordinate system can be set accurately without rotating the first vehicle body. [Brief explanation of the drawing]

[0012] [Figure 1] This is a side view of the work machine. [Figure 2] This is a block diagram showing the configuration of a work machine and its control system. [Figure 3]It is a schematic side view showing a working machine, an external coordinate system, and a vehicle body coordinate system. [Figure 4] It is a schematic rear view showing a working machine, an external coordinate system, and a vehicle body coordinate system. [Figure 5] It is a schematic top view showing a working machine, an external coordinate system, and a vehicle body coordinate system. [Figure 6] It is a flowchart showing a process for calibrating machine parameters. [Figure 7] It is a diagram showing an example of a first target part. [Figure 8] It is a diagram showing an example of a second target part. [Figure 9] It is a diagram showing an example of a second target part. [Figure 10] It is a diagram showing an example of a second target part. [Figure 11] It is a diagram showing a method for evaluating calibration accuracy. [Figure 12] It is a diagram showing an example of automatic control of a working machine using the detected cutting edge position. [Figure 13] It is a diagram showing an example of an assistant screen of a working machine using the detected cutting edge position.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, a control system of a working machine 1 according to an embodiment will be described while referring to the drawings. FIG. 1 is a side view of the working machine 1. In the present embodiment, the working machine 1 is an excavator such as a hydraulic excavator.

[0014] As shown in FIG. 1, the working machine 1 includes a main body 2 and a working device 3. The working device 3 is attached to the front portion of the main body 2. The main body 2 includes a first vehicle body 4 and a second vehicle body 5. The first vehicle body 4 is rotatably connected to the second vehicle body 5. A cab 6 is disposed on the first vehicle body 4. The second vehicle body 5 includes crawlers 7. In FIG. 1, only one of the left and right crawlers 7 is shown. By driving the crawlers 7, the working machine 1 travels.

[0015] The work implement 3 is mounted on the first vehicle body 4 so as to be movable up and down. The work implement 3 includes a boom 11, an arm 12, and a bucket 13. The boom 11 is mounted on the first vehicle body 4 so as to be rotatable around a boom pin 28. The arm 12 is mounted on the boom 11 so as to be rotatable around an arm pin 29. The bucket 13 is mounted on the arm 12 so as to be rotatable around a bucket pin 30.

[0016] The work machine 3 includes a boom cylinder 14, an arm cylinder 15, and a bucket cylinder 16. The boom cylinder 14, arm cylinder 15, and bucket cylinder 16 are, for example, hydraulic cylinders. The boom cylinder 14, arm cylinder 15, and bucket cylinder 16 are driven by hydraulic fluid from a hydraulic pump 22, which will be described later. The boom cylinder 14 operates the boom 11. The arm cylinder 15 operates the arm 12. The bucket cylinder 16 operates the bucket 13.

[0017] Figure 2 is a block diagram showing the configuration of the work machine 1 and its control system. As shown in Figure 2, the work machine 1 includes a drive source 21, a hydraulic pump 22, a power transmission device 23, and a controller 24. The drive source 21 is controlled by command signals from the controller 24. The drive source 21 is, for example, an internal combustion engine. Alternatively, the drive source may include an electric motor or a hydrogen engine. The hydraulic pump 22 is driven by the drive source 21 and discharges hydraulic fluid. The hydraulic fluid discharged from the hydraulic pump 22 is supplied to the boom cylinder 14, the arm cylinder 15, and the bucket cylinder 16.

[0018] The work machine 1 includes a slewing motor 25. The slewing motor 25 is, for example, a hydraulic motor. The slewing motor 25 is driven by hydraulic fluid from a hydraulic pump 22. Alternatively, the slewing motor 25 may be an electric motor. The slewing motor 25 rotates the first vehicle body 4. Although one hydraulic pump is shown in Figure 2, multiple hydraulic pumps may be provided.

[0019] The hydraulic pump 22 is a variable displacement pump. A pump control device 26 is connected to the hydraulic pump 22. The pump control device 26 controls the tilt angle of the hydraulic pump 22. The pump control device 26 includes, for example, a solenoid valve and is controlled by command signals from the controller 24. The controller 24 controls the capacity of the hydraulic pump 22 by controlling the pump control device 26.

[0020] The work machine 1 includes a control valve 27. The hydraulic pump 22, cylinders 14-16, and swing motor 25 are connected by a hydraulic circuit via the control valve 27. The control valve 27 is controlled by command signals from the controller 24. The control valve 27 controls the flow rate of hydraulic fluid supplied from the hydraulic pump 22 to the cylinders 14-16 and the swing motor 25. The controller 24 controls the operation of the work machine 3 by controlling the control valve 27. The controller 24 controls the swing of the first vehicle body 4 by controlling the control valve 27. Note that the cylinders 14-16 are not limited to hydraulic cylinders, but may also be mechanical cylinders driven by an electric motor.

[0021] The power transmission device 23 transmits the driving force from the drive source 21 to the second vehicle body 5. The tracks 7 are driven by the driving force from the power transmission device 23 to move the work machine 1. The power transmission device 23 may be, for example, a torque converter or a transmission with multiple gears. Alternatively, the power transmission device 23 may be another type of transmission such as an HST (Hydro Static Transmission) or an HMT (Hydraulic Mechanical Transmission).

[0022] The controller 24 includes a processor 31, such as a CPU. The processor 31 performs processing for controlling the work machine 1. The controller 24 also includes a storage device 32. The storage device 32 includes memory such as RAM or ROM, and auxiliary storage such as an HDD (Hard Disk Drive) or SSD (Solid State Drive). The storage device 32 stores data and programs for controlling the work machine 1.

[0023] The control system includes an operating device 33. The operating device 33 is operable by an operator. The operating device 33 includes, for example, a lever, pedal, or switch. The operating device 33 outputs an operation signal to the controller 24 in response to the operator's operation of the operating device 33. The controller 24 controls the control valve 27 to operate the work machine 3 in response to the operator's operation of the operating device 33. The controller 24 controls the control valve 27 to rotate the first vehicle body 4 in response to the operator's operation of the operating device 33. The controller 24 controls the drive source 21 and the power transmission device 23 to drive the work machine 1 in response to the operator's operation of the operating device 33.

[0024] The control system includes an input device 34 and a display 35. The input device 34 is operable by an operator. The input device 34 is, for example, a touchscreen. However, the input device 34 may also include hardware keys. The operator inputs various settings for the work machine 1 by operating the input device 34. The input device 34 outputs input signals corresponding to the operator's operations. The display 35 is, for example, an LCD, OLED, or other type of display. The display 35 displays a screen corresponding to a display signal from the controller 24.

[0025] The control system includes a position sensor 36, an attitude sensor 37, and a work machine sensor 38. The position sensor 36 detects the position of the main body 2. The position of the main body 2 is indicated in an external coordinate system. The external coordinate system is a coordinate system based on the area outside the work machine 1. The external coordinate system is, for example, a global coordinate system based on GNSS (Global Navigation Satellite System). Alternatively, the external coordinate system may be the site coordinate system within the work site where the work machine 1 is used.

[0026] Figure 3 is a schematic side view showing the work machine 1 and the external coordinate system X1-Y1-Z1 and the vehicle body coordinate system X2-Y2-Z2. Figure 4 is a schematic rear view showing the work machine 1 and the external coordinate system X1-Y1-Z1 and the vehicle body coordinate system X2-Y2-Z2. Figure 5 is a schematic top view showing the work machine 1 and the external coordinate system X1-Y1-Z1 and the vehicle body coordinate system X2-Y2-Z2.

[0027] As shown in Figure 3, the position sensor 36 includes an antenna 41 and a receiver 42. The antenna 41 is attached to the main body 2. The receiver 42 detects the position P1 of the antenna 41 in the external coordinate system X1-Y1-Z1 (hereinafter referred to as "antenna position"). The receiver 42 outputs antenna position data indicating the antenna position P1 in the external coordinate system X1-Y1-Z1. Note that there may be multiple antenna positions.

[0028] The attitude sensor 37 is attached to the first vehicle body 4. The attitude sensor 37 detects the attitude of the first vehicle body 4. The attitude of the first vehicle body 4 is determined by the yaw angle θ of the first vehicle body 4. y1 And, the pitch angle θ p1 And, roll angle θ r1 This includes the following. As shown in Figure 3, the pitch angle θ of the first vehicle body 4 p1 This is the longitudinal tilt angle of the first vehicle body 4. As shown in Figure 4, the roll angle θ of the first vehicle body 4. r1 This is the lateral tilt angle of the first vehicle body 4. As shown in Figure 5, the yaw angle θ of the first vehicle body 4 y1This represents the longitudinal orientation of the first vehicle body 4. The attitude sensor 37 is, for example, an IMU (Inertial Measurement Unit). The attitude sensor 37 outputs first attitude data indicating the attitude of the first vehicle body 4.

[0029] The work equipment sensor 38 detects the posture of the work equipment 3. The work equipment 3 is mounted on the first vehicle body 4 so as to be operable within the work equipment plane 50 shown in Figures 4 and 5. The work equipment plane 50 is a plane that the work equipment 3 passes through when it is in operation. For example, the work equipment plane 50 is a virtual plane that passes through the center of the work equipment 3 in the left-right direction and extends in the up-down and front-rear directions of the first vehicle body 4. Note that the work equipment plane 50 is not limited to the center of the work equipment 3 in the left-right direction, but may also pass through positions offset to the left and right from the center. The posture of the work equipment 3 changes as the boom 11, arm 12, and bucket 13 each rotate within this work equipment plane 50.

[0030] As shown in Figure 3, the posture of the work machine 3 includes the boom angle θ1, the arm angle θ2, and the bucket angle θ3. The work machine sensor 38 outputs second posture data indicating the boom angle θ1, the arm angle θ2, and the bucket angle θ3. The boom angle θ1 is the angle of the boom 11 with respect to the vertical direction of the vehicle body coordinate system of the main body 2. The arm angle θ2 is the angle of the arm 12 with respect to the boom 11. The bucket angle θ3 is the angle of the bucket 13 with respect to the arm 12.

[0031] In detail, the work equipment sensor 38 includes a boom angle sensor 38A, an arm angle sensor 38B, and a bucket angle sensor 38C, as shown in Figure 3. The boom angle sensor 38A detects the boom angle θ1. The arm angle sensor 38B detects the arm angle θ2. The bucket angle sensor 38C detects the bucket angle θ3.

[0032] In detail, the boom angle sensor 38A detects the stroke length of the boom cylinder 14. The arm angle sensor 38B detects the stroke length of the arm cylinder 15. The bucket angle sensor 38C detects the stroke length of the bucket cylinder 16. From the stroke lengths of each cylinder 14-16, the rotation angles θ1-θ3 of the boom 11, arm 12, and bucket 13 are calculated. Alternatively, the boom angle sensor 38A, arm angle sensor 38B, and bucket angle sensor 38C may be sensors that directly detect the rotation angles θ1-θ3 of the boom 11, arm 12, and bucket 13, respectively. Alternatively, the boom angle sensor 38A, arm angle sensor 38B, and bucket angle sensor 38C may be IMUs.

[0033] The controller 24 receives an operation signal from the operating device 33. The controller 24 receives an input signal from the input device 34. The controller 24 outputs a display signal to the display 35. The controller 24 receives antenna position data from the position sensor 36. The controller 24 receives first posture data from the posture sensor 37. The controller 24 receives second posture data from the work machine sensor 38.

[0034] The controller 24 calculates the position of the work implement 3 based on the received data and machine parameters. More specifically, the controller 24 calculates the position of the cutting edge of the bucket 13 (hereinafter referred to as the "cutting edge position") P2 based on the received data and machine parameters. The controller 24 calculates the cutting edge position P2 in the external coordinate system X1-Y1-Z1 described above.

[0035] The machine parameters are stored in the memory device 32. The machine parameters define the positional relationship between the antenna 41 and the cutting edge position P2 of the work implement 3 in the vehicle body coordinate system X2-Y2-Z2. As shown in Figures 3 to 5, the vehicle body coordinate system X2-Y2-Z2 is a coordinate system based on a virtual origin set on the first vehicle body 4. The X2 axis of the vehicle body coordinate system X2-Y2-Z2 indicates the front-rear direction of the first vehicle body 4. The Y2 axis of the vehicle body coordinate system X2-Y2-Z2 indicates the left-right direction of the first vehicle body 4. The Z2 axis of the vehicle body coordinate system X2-Y2-Z2 indicates the up-down direction of the first vehicle body 4.

[0036] The machine parameters include antenna parameters and work implement parameters. The antenna parameters indicate the relative position of the antenna position P1 with respect to a reference position such as the boom pin 28 in the vehicle coordinate system X2-Y2-Z2. The reference position is not limited to the boom pin 28, but may be any other position. As shown in Figures 3 and 4, the antenna parameters include the distance Lx in the X2 axis direction, the distance Ly in the Y2 axis direction, and the distance Lz in the Z2 axis direction between the antenna position P1 and the boom pin 28 in the vehicle coordinate system X2-Y2-Z2.

[0037] As shown in Figure 3, the implement parameters include the length L1 of the boom 11, the length L2 of the arm 12, and the length L3 of the bucket 13. In detail, the length L1 of the boom 11 is the distance between the boom pin 28 and the arm pin 29. The length L2 of the arm 12 is the distance between the arm pin 29 and the bucket pin 30. The length of the bucket 13 is the distance between the bucket pin 30 and the cutting edge of the bucket 13.

[0038] The controller 24 calculates the cutting edge position P2 in the external coordinate system X1-Y1-Z1 based on the antenna position P1 in the external coordinate system X1-Y1-Z1, the machine parameters, the first attitude data, and the second attitude data. For example, the controller 24 calculates the positional relationship between the antenna position P1 and the cutting edge position P2 in the vehicle body coordinate system X2-Y2-Z2 based on the machine parameters and the second attitude data. The controller 24 calculates the positional relationship between the external coordinate system X1-Y1-Z1 and the vehicle body coordinate system X2-Y2-Z2 from the first attitude data. The controller 24 then converts the positional relationship between the antenna position P1 and the blade tip position P2 in the vehicle body coordinate system X2-Y2-Z2, and the positional relationship between the external coordinate system X1-Y1-Z1 and the vehicle body coordinate system X2-Y2-Z2, to the blade tip position P2 in the external coordinate system X1-Y1-Z1.

[0039] As described above, the controller 24 calculates the cutting edge position P2 in the external coordinate system X1-Y1-Z1 from the antenna position P1 in the external coordinate system X1-Y1-Z1 detected by the position sensor 36.

[0040] Next, we will describe the process of calibrating the machine parameters used to calculate the cutting edge position P2. Figure 6 is a flowchart showing the process for calibrating the machine parameters. The parameters to be calibrated may be all or some of the machine parameters described above.

[0041] First, in steps S101 to S104, the controller 24 sets the vehicle coordinate system X2-Y2-Z2 for the work machine 1. As shown in Figure 6, in step S101, the controller 24 acquires the position of the first target part. The first target part is the part measured to set the vehicle coordinate system X2-Y2-Z2 and is included in the work machine 3. As shown in Figure 7, the first target part is, for example, the bucket pin 30. However, the first target part may be the arm pin 29. Alternatively, the first target part may be a specific part included in the boom 11, arm 12, or bucket 13. The controller 24 acquires at least three different positions of the bucket pin 30 as the first target part.

[0042] The position of the first target is measured by an external position measuring device 45. The position measuring device 45 measures the position of the object to be measured in the external coordinate system X1-Y1-Z1. The position measuring device 45 is, for example, a laser tracker. Alternatively, the position measuring device 45 may be other position measuring devices such as a total station or a stereo camera. The operator of the work machine 1 operates the work machine 3 within the work machine plane 50 relative to the first vehicle body 4, with the first vehicle body 4 stationary and not rotated relative to the second vehicle body 5. At this time, the position measuring device 45 measures multiple different positions of the first target.

[0043] The multiple positions of the first target unit that have been measured are input to the controller 24. The position measuring device 45 is capable of communicating with the controller 24 and transmits data indicating the multiple positions of the first target unit to the controller 24. Alternatively, the data indicating the multiple positions of the first target unit may be input to the controller 24 by manual input via the input device 34.

[0044] In step S102, the controller 24 acquires first attitude data. As described above, the first attitude data is the pitch angle θ of the first vehicle body 4 detected by the attitude sensor 37. p1 Includes.

[0045] In step S103, the controller 24 calculates the implement plane 50. The implement plane 50 includes a plurality of positions of the first target part. When there are four or more positions of the first target part, the implement plane 50 may be the least-squares plane calculated from the plurality of positions. The implement plane 50 is represented by the following formula (1). In the following formula (1), a1, b1, and c1 represent the normal vector of the implement plane 50. The controller 24 calculates the normal vector of the implement plane 50 based on the plurality of positions of the first target part. TIFF0007881424000001.tif7170

[0046] In step S104, the controller 24 sets the vehicle body coordinate system X2 - Y2 - Z2. The controller 24 determines the direction of the Y2 axis of the vehicle body coordinate system X2 - Y2 - Z2 based on the normal vector of the implement plane 50. The controller 24 determines the direction of the X2 axis of the vehicle body coordinate system X2 - Y2 - Z2 based on the pitch angle θ p1 of the first vehicle body 4 detected by the attitude sensor 37. Then, the controller 24 determines the direction of the Z2 axis of the vehicle body coordinate system X2 - Y2 - Z2 based on the direction of the Y2 axis and the direction of the X2 axis. Specifically, the controller 24 sets the vehicle body coordinate system X2 - Y2 - Z2 by calculating the rotation matrix R of the vehicle body coordinate system X2 - Y2 - Z2 with respect to the external coordinate system X1 - Y1 - Z1 as follows.

[0047] The rotation matrix R of the vehicle body coordinate system X2 - Y2 - Z2 is represented by the following formula (2) using the yaw angle θ Y2 , pitch angle θ p2 , and roll angle θ r2 as the Euler angles representing the rotational posture of the vehicle body coordinate system X2 - Y2 - Z2. TIFF0007881424000002.tif40170

[0048] The Y2 - axis direction vector of the vehicle body coordinate system X2 - Y2 - Z2 coincides with the normal vector of the implement plane 50 described above. Therefore, the following formula (3) holds from the Y2 - axis direction vector in formula (2) and the normal vector of the implement plane 50. TIFF0007881424000003.tif21170

[0049] Pitch angle θ in vehicle coordinate system X2-Y2-Z2 p2 This is the pitch angle θ detected by the attitude sensor 37. p1 This matches. Therefore, the pitch angle θ detected by the attitude sensor 37 p1 The pitch angle θ in equation (3) p2 By substituting and expanding equation (3), we obtain the following equations (4), (5), and (6), where the Euler angle representing the rotational orientation in the vehicle coordinate system X2-Y2-Z2 is the pitch angle θ. p2 , roll angle θ r2 , yaw angle θ y2 These can be determined. TIFF0007881424000004.tif38170 And the yaw angle θ in equations (4), (5), and (6) y2 , pitch angle θ p2 , roll angle θ r2 By substituting this into equation (2) above, the rotation matrix R for the vehicle coordinate system X2-Y2-Z2 can be obtained.

[0050] Next, as shown in Figure 6, in steps S105 and S106, the controller 24 performs calibration of the mechanical parameters using the set vehicle coordinate system X2-Y2-Z2. In step S105, the controller 24 acquires the position of the second target part. The second target part is the part that is measured in order to perform calibration of the mechanical parameters.

[0051] As shown in Figure 8, the second target section includes the boom pin 28 and the antenna position P1. The controller 24 acquires the boom pin 28 and the antenna position P1. As shown in Figure 9, the second target section includes the bucket pin 30. The operator acquires the positions of multiple different bucket pins 30 by operating the work implement 3. As shown in Figure 10, the second target section includes the cutting edge position P2. The operator acquires multiple different cutting edge positions P2 by operating the work implement 3. However, the second target section may include parts other than those described above. For example, the second target section may include the arm pin 29. The controller 24 may also acquire the positions of multiple second target sections in one orientation of the work implement 3.

[0052] The position of the second target is measured by an external position measuring device 45. The position measuring device 45 is equipped with a camera 46, which locks onto the position of the object to be measured and measures it. The controller 24 calculates the position of the second target in the vehicle coordinate system X2-Y2-Z2, and using the set vehicle coordinate system X2-Y2-Z2, converts the position of the second target in the vehicle coordinate system X2-Y2-Z2 to the position of the second target in the external coordinate system X1-Y1-Z1 and transmits it to the position measuring device 45. The position measuring device 45 locks onto the position of the second target by pointing the camera 46 at the position of the second target received from the controller 24 and measures it. The position measuring device 45 transmits the measured position of the second target (hereinafter referred to as the "external measurement value") to the controller 24.

[0053] The position of the second target unit transmitted from the controller 24 to the position measuring device 45 is an approximate position with low accuracy because it is calculated using pre-calibration machine parameters. However, based on the approximate position of the second target unit, the position measuring device 45 can automatically lock onto the second target unit using the camera 46 even if the second target unit moves. This allows the position measuring device 45 to automatically switch which second target unit to lock onto. For example, the position measuring device 45 can automatically switch the second target unit to lock onto from the arm pin 29 to the bucket pin 30.

[0054] In step S106, the controller 24 performs calibration of the machine parameters. Based on the first posture data, the second posture data, and the machine parameters, the controller 24 calculates the position of the second target part in the external coordinate system X1-Y1-Z1 (hereinafter referred to as the "calculated value"). The controller 24 performs calibration of the machine parameters based on the error between the externally measured value and the calculated value of the position of the second target part. Alternatively, the controller 24 may perform calibration of the machine parameters based on the externally measured value of the position of the second target part. Known calibration methods may be used for the specific calibration method of the machine parameters. For example, the positions of the arm pin 29 and the bucket pin 30 may be measured, and the length L2 of the arm 12 may be calibrated by the distance calculated from the measured positions of the arm pin 29 and the bucket pin 30. Alternatively, the length of the arm 12 may be calibrated so that the error evaluation function between the measured value and the calculated value of the position of the arm pin 29 in multiple postures of the work machine 3 is minimized.

[0055] Then, in step S107, the controller 24 evaluates the accuracy of the calibration. As shown in Figure 11, the position measuring device 45 measures the blade tip position P2 and the antenna position P1 and transmits them to the controller 24. Based on the blade tip position P2 and antenna position P1 received from the position measuring device 45, the controller 24 calculates a vector (hereinafter referred to as the "external measurement value") from the antenna position P1 to the blade tip position P2.

[0056] Meanwhile, the controller 24 calculates a vector from the antenna position P1 to the blade tip position P2 using the vehicle coordinate system X2-Y2-Z2. Without using the position data detected by the position sensor 36, the controller 24 calculates a vector from the antenna position P1 to the blade tip position P2 (hereinafter referred to as the "calculated value") using the first attitude data, the second attitude data, and the machine parameters. The controller 24 calculates the error by comparing the externally measured value and the calculated value of the vector from the antenna position P1 to the blade tip position P2.

[0057] The controller 24 evaluates the accuracy of the calibration based on the error between the externally measured value and the calculated value of the vector from the antenna position P1 to the blade tip position P2. For example, the controller 24 may display a message or image on the display indicating that the calibration was successful when the error is below a threshold. The controller 24 may display a message or image on the display prompting the user to repeat the calibration when the error is greater than the threshold.

[0058] In the control system of the work machine 1 according to this embodiment described above, instead of determining the rotation plane of the first vehicle body 4, the vehicle body coordinate system X2-Y2-Z2 is set based on the attitude of the first vehicle body 4 detected by the attitude sensor 37. Therefore, in the work machine 1, the vehicle body coordinate system X2-Y2-Z2 can be set accurately without rotating the first vehicle body 4.

[0059] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention.

[0060] The work machine 1 is not limited to a hydraulic excavator, but may also be other types of work machines including a first vehicle body and a second vehicle body rotatably connected to the first vehicle body, such as a crane, wheel loader, or motor grader. The configuration of the work machine 1 is not limited to those described above and may be changed to other attachments.

[0061] The controller 24 may have multiple processors. The above processing may be distributed and executed by multiple processors. The controller 24 is not limited to one unit; the above processing may be distributed and executed by multiple controllers. The controller 24 may be located outside the work machine 1. The machine parameters are not limited to those of the above embodiment and may be changed, omitted, or added.

[0062] The work machine 1 may be operable remotely. In that case, the operating device 33 may be located outside the work machine 1. The work machine 1 may be automatically controlled. In that case, the operating device 33 may be omitted.

[0063] The controller 24 may use the calculated cutting edge position P2 to automatically control the work machine 1. For example, as shown in Figure 12, the controller 24 acquires current terrain data showing the current terrain 51 of the construction target. The controller 24 acquires the target trajectory 52 of the cutting edge of the bucket 13 for performing construction work such as excavation. The controller 24 automatically controls the work machine 3 so that the calculated cutting edge position P2 moves along the target trajectory 52.

[0064] Alternatively, the controller 24 may use the calculated cutting edge position P2 to display an assistant screen on the display. For example, as shown in Figure 13, the assistant screen 53 includes an image showing the current terrain 54 and an image showing the target terrain 55. Based on the calculated cutting edge position P2, the controller 24 displays images showing the work machine 1 and the cutting edge position P2 at positions corresponding to the current terrain 54 and the target terrain 55. [Industrial applicability]

[0065] According to the present invention, in a work machine, the vehicle body coordinate system can be set with high accuracy without rotating the first vehicle body. [Explanation of Symbols]

[0066] 3. Work equipment 4. First vehicle body 5. Second vehicle body 28. Boom pin (second target section) 30. Bucket pins (first target section, second target section) 36. Position sensor 37. Posture Recovery 45. Position measuring device 52...Target trajectory P1... Antenna position (second target area) P2...Blade tip position (second target area) X1-Y1-Z1...External coordinate system X2-Y2-Z2...vehicle coordinate system

Claims

1. A work machine comprising a first vehicle body, a second vehicle body that pivotably supports the first vehicle body, and a work machine movably mounted to the first vehicle body, wherein the work machine is movably mounted to the first vehicle body within a work machine plane extending in the vertical and longitudinal directions of the first vehicle body, and a system for setting a vehicle body coordinate system with respect to the first vehicle body, An attitude sensor for detecting the attitude of the first vehicle body, including the pitch angle of the first vehicle body, A position measuring device for measuring the position of a first target portion included in the work machine in an external coordinate system that uses the outside of the work machine as a reference, Controller and Equipped with, The aforementioned controller, The attitude of the first vehicle body while it is stationary relative to the second vehicle body is obtained from the attitude sensor. With the first vehicle body stationary relative to the second vehicle body, the work implement is operated to acquire multiple positions of the first target portion within the plane of the work implement. Based on the attitude of the first vehicle body and the multiple positions of the first target portion, the vehicle body coordinate system is set. Based on the pitch angle of the first vehicle body, the direction of the x-axis of the vehicle body coordinate system indicating the longitudinal direction of the first vehicle body is determined. Based on the multiple positions of the first target portion, the normal vector of the work machine plane is calculated. Based on the normal vector of the work machine plane, the direction of the y-axis of the vehicle body coordinate system, which indicates the left-right direction of the first vehicle body, is determined. system.

2. The controller determines the direction of the z-axis of the vehicle body coordinate system, which indicates the vertical direction of the first vehicle body, based on the direction of the y-axis and the direction of the x-axis. The system according to claim 1.

3. The aforementioned work machine further includes a position sensor, The position sensor detects the position of the position sensor in the external coordinate system, The aforementioned controller, The system stores mechanical parameters that define the positional relationship between the position sensor and the cutting edge of the work machine in the vehicle body coordinate system. Based on the position of the position sensor in the external coordinate system and the machine parameters, the position of the cutting edge in the external coordinate system is calculated. The system according to claim 1.

4. The aforementioned controller, The target trajectory of the cutting edge for performing the prescribed construction work is obtained, Based on the position of the cutting edge in the external coordinate system, the work machine is controlled so that the cutting edge moves according to the target trajectory. The system according to claim 3.

5. The position measuring device measures the position of the second target portion included in the work machine in the external coordinate system. The aforementioned controller, The system stores machine parameters that define the dimensions of the aforementioned work machine. Based on the measured position of the second target portion, the machine parameters are calibrated. The system according to claim 1.

6. The controller transmits to the position measuring device the position of the second target in the external coordinate system calculated using the machine parameters before calibration. The position measuring device automatically switches the measurement of multiple positions of the second target unit based on the position of the second target unit received from the controller. The system according to claim 5.

7. The aforementioned work machine further includes a position sensor, The position sensor detects the position of the position sensor in the external coordinate system, The position measuring device measures the position of the cutting edge of the work machine in the external coordinate system and the position of the position sensor in the external coordinate system. The aforementioned controller, Based on the measured position of the cutting edge and the measured position of the position sensor, an external measurement value indicating the position of the cutting edge relative to the position sensor is generated. Based on the calibrated machine parameters, the position of the cutting edge relative to the position sensor is calculated to generate a calculated value indicating the position of the cutting edge relative to the position sensor. The accuracy of the calibration of the machine parameters is evaluated by comparing the externally measured values ​​with the calculated values. The system according to claim 5.

8. A method for setting a vehicle coordinate system with respect to the first vehicle in a work machine comprising a first vehicle body, a second vehicle body that pivotably supports the first vehicle body, and a work machine movably mounted to the first vehicle body, wherein the work machine is movably mounted to the first vehicle body within a work machine plane extending in the vertical and longitudinal directions of the first vehicle body, The attitude of the first vehicle body is obtained by an attitude sensor that detects the attitude of the first vehicle body, including the pitch angle of the first vehicle body, while the first vehicle body is stationary relative to the second vehicle body. The position of the first target portion included in the work machine is measured in an external coordinate system based on the outside of the work machine, and by operating the work machine while the first vehicle body is stationary relative to the second vehicle body, multiple positions of the first target portion within the plane of the work machine are obtained. Based on the attitude of the first vehicle body and the multiple positions of the first target portion, the vehicle body coordinate system is set. Equipped with, Setting the aforementioned vehicle body coordinate system means that Based on the pitch angle of the first vehicle body, the direction of the x-axis of the vehicle body coordinate system indicating the longitudinal direction of the first vehicle body is determined, Based on the multiple positions of the first target portion, the normal vector of the work machine plane is calculated, Based on the normal vector of the work machine plane, the direction of the y-axis of the vehicle body coordinate system, which indicates the left-right direction of the first vehicle body, is determined. including, method.

9. Setting the vehicle body coordinate system includes determining the direction of the z axis of the vehicle body coordinate system, which indicates the vertical direction of the first vehicle body, based on the direction of the y axis and the direction of the x axis. The method according to claim 8.

10. The aforementioned work machine further includes a position sensor, The position sensor detects the position of the position sensor in the external coordinate system, Based on the mechanical parameters defining the positional relationship between the position sensor and the cutting edge of the work machine in the vehicle body coordinate system, and the position of the position sensor in the external coordinate system, the position of the cutting edge in the external coordinate system is calculated. The method according to claim 8, further comprising:

11. To obtain the target trajectory of the cutting edge for performing the prescribed construction work, Based on the position of the cutting edge in the external coordinate system, the work machine is controlled so that the cutting edge moves according to the target trajectory. The method according to claim 10, further comprising:

12. To obtain the position of the second target portion included in the work machine in the external coordinate system, as measured by the position measuring device, Calibrating the machine parameters that define the dimensions of the work machine based on the measured position of the second target part, The method according to claim 8, further comprising:

13. The position of the second target in the external coordinate system, calculated using the machine parameters before calibration, is transmitted to the position measuring device. The position measuring device switches the measurement of multiple positions of the second target based on the received position of the second target, The method according to claim 12, further comprising:

14. The aforementioned work machine further includes a position sensor, The position sensor detects the position of the position sensor in the external coordinate system, The position of the cutting edge of the work machine in the external coordinate system, measured by the position measuring device, and the position of the position sensor in the external coordinate system are obtained. Based on the measured position of the cutting edge and the measured position of the position sensor, an external measurement value indicating the position of the cutting edge relative to the position sensor is generated. Based on the calibrated machine parameters, the position of the cutting edge relative to the position sensor is calculated to generate a calculated value indicating the position of the cutting edge relative to the position sensor. The accuracy of the calibration of the machine parameters is evaluated by comparing the externally measured values ​​with the calculated values. The method according to claim 12, further comprising:

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