WO2023166885A1

WO2023166885A1 - Information calibration method

Info

Publication number: WO2023166885A1
Application number: PCT/JP2023/002169
Authority: WO
Inventors: 隆之片岡; 崇幸篠田; 光内田; 創一茨木
Original assignee: 株式会社小松製作所; 国立大学法人広島大学
Priority date: 2022-03-04
Filing date: 2023-01-25
Publication date: 2023-09-07
Also published as: JP2023128874A

Abstract

The present invention accurately calibrates information pertaining to a work machine by means of simple tasks. This information calibration method comprises: stopping a measurement target at at least three different measurement points in a plane, in order; measuring the posture of a work machine relative to a vehicle body when the measurement target is stopped at each measurement point; measuring the distance between each of the measurement points; and deriving information in which the difference is minimized between measurement point measurement coordinates based on the distances and in a coordinate system defined in the plane, and measurement point calculated coordinates calculated using the posture and the information, and updating the information.

Description

Information calibration method

The present disclosure relates to an information calibration method for calibrating information about work machines.

Information-aided construction is the use of information and communication technology (ICT) in the construction and civil engineering business to achieve highly efficient and highly accurate construction. As an example of information-aided construction technology, we acquire the position of the work machine using a position measuring device such as a total station or GNSS (Global Navigation Satellite Systems), and compare the design data of the construction site with the current topographical data. Machine guidance techniques have been proposed to provide differential information to a work machine cab monitor.

A hydraulic excavator is one of the work machines. A hydraulic excavator may include a working machine that includes a boom, an arm, and a bucket. The boom, arm and bucket may in turn be pivotally supported by pins. Regarding construction using machine guidance technology, Non-Patent Document 1 describes measuring the dimensions between pins and bucket dimensions of each movable part such as arm dimensions of an ICT hydraulic excavator.

　In order to ensure the accuracy of information-aided construction, it is necessary to accurately acquire the position data of work machines. In the case of excavators, this position data refers to the position data of the tip of the bucket. The position data of the tip of the bucket is calculated from the position information of the GNSS antenna provided in the main body of the hydraulic excavator, the geometric shape of the work machine, and the information of the attitude of the work machine. Geometry includes the distance between each pin of the links that make up the implement. The distance between each pin is stored as information in the in-machine controller and calibrated prior to installation.

In order to calibrate the distance between each pin of a work machine, a survey target is attached to each pin position, and the position of each pin is measured using a surveying instrument such as a total station or laser tracker. Ta. These surveying instruments are expensive and therefore costly to calibrate. It is desired to provide a simple calibration method without preparing expensive surveying equipment at the construction site.

This disclosure proposes an information calibration method that can inexpensively and easily calibrate information about work machines for information-aided construction.

According to the present disclosure, an information calibration method for calibrating information about work machines is proposed. The working machine has a vehicle body and a working machine that is relatively movable with respect to the vehicle body. A measurement target is set on the working machine of the working machine. The information calibration method comprises the following processes. The first process is to sequentially stop the measurement target at at least three different measurement points on the plane. The second process is to measure the posture of the work implement with respect to the vehicle body while the measurement target is stopped at each measurement point. The third process is to measure the distance between each measurement point. The fourth processing is the calculation of the measurement points using the measurement coordinates of the measurement points based on the distance between the measurement points in the coordinate system defined on the plane, and the attitude of the work machine and information about the work machine. and updating the information by deriving information that minimizes the difference between the coordinates.

According to the information calibrating method according to the present disclosure, it is possible to calibrate information about work machines easily and inexpensively.

1 is an external view of a hydraulic excavator; FIG. It is a side view of a hydraulic excavator. FIG. 4 is a flow diagram showing a flow of processing for calibrating information about a hydraulic excavator; FIG. 11 is a schematic side view showing an operation of aligning the cutting edge of the bucket with the first measurement point; FIG. 11 is a schematic side view showing an operation of aligning the blade edge of the bucket with the second measurement point; FIG. 11 is a schematic side view showing an operation of aligning the blade edge of the bucket with the third measurement point; It is a side schematic diagram showing the coordinates of the boom pin.

The embodiment will be described below based on the drawings. In the following description, the same reference numerals are given to the same parts. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

FIG. 1 is an external view of a hydraulic excavator 100 as an example of a working machine whose information is calibrated by the information calibrating method based on the embodiment. In the embodiments, a hydraulic excavator 100 will be described as an example of a working machine.

As shown in FIG. 1, the hydraulic excavator 100 has a main body 1 and a work machine 2 that operates hydraulically. The main body 1 has a revolving body 3 and a traveling body 5 . The traveling body 5 has a pair of crawler belts 5Cr and a traveling motor 5M. The traveling motor 5M is provided as a drive source for the traveling body 5. As shown in FIG. The traveling motor 5M is a hydraulic motor operated by hydraulic pressure.

During operation of the hydraulic excavator 100, the traveling body 5, more specifically the crawler belt 5Cr, is in contact with the ground. The traveling body 5 can travel on the ground by rotating the crawler belt 5Cr. Note that the traveling body 5 may have wheels (tires) instead of the crawler belts 5Cr.

The revolving body 3 is arranged on the running body 5 and supported by the running body 5 . The revolving body 3 is relatively movable with respect to the traveling body 5 . The revolving body 3 is mounted on the running body 5 so as to be able to revolve with respect to the running body 5 about the revolving axis RX. The revolving body 3 is mounted on the traveling body 5 via a revolving circle portion. The turning circle portion is arranged substantially in the center of the main body 1 in plan view. The turning circle portion has an annular general shape, and has internal teeth for turning on its inner peripheral surface. A pinion that meshes with the internal teeth is attached to a turning motor (not shown). The revolving body 3 can rotate relative to the traveling body 5 by rotating the revolving circle portion by transmitting the driving force from the revolving motor.

The revolving body 3 has a cab 4. A crew member (operator) of the hydraulic excavator 100 rides on the cab 4 and steers the hydraulic excavator 100 . The cab 4 is provided with a driver's seat 4S on which an operator sits. An operator can operate the excavator 100 inside the cab 4 . In the cab 4 , the operator can operate the work implement 2 , can swivel the revolving body 3 with respect to the traveling body 5 , and can operate the excavator 100 to travel by the traveling body 5 . The excavator 100 may be wirelessly remotely controlled from a location away from the excavator 100 .

In the embodiment, the positional relationship of each part of the revolving body 3 of the hydraulic excavator 100 will be described with reference to the operator seated in the driver's seat 4S in the cab 4. The front-back direction refers to the front-back direction of the operator seated on the driver's seat 4S. The direction facing the operator seated on the driver's seat 4S is the forward direction, and the direction behind the operator seated on the driver's seat 4S is the rearward direction. The left-right direction refers to the left-right direction of the operator seated on the driver's seat 4S. The right side and the left side when an operator sitting in the driver's seat 4S faces the front are the right direction and the left direction, respectively. The vertical direction refers to the vertical direction of the operator seated on the driver's seat 4S. The operator seated on the driver's seat 4S faces the lower side, and the upper side faces the operator's head.

In the front-rear direction, the side where the working machine 2 protrudes from the revolving body 3 is the front direction, and the direction opposite to the front direction is the rear direction. The right side and the left side in the horizontal direction are the right direction and the left direction, respectively, when viewed in the forward direction. In the vertical direction, the side with the ground is the lower side, and the side with the sky is the upper side.

The revolving body 3 has an engine room 9 in which the engine is housed, and a counterweight provided at the rear part of the revolving body 3 . In the engine room 9, an engine that generates a driving force, a hydraulic pump that receives the driving force generated by the engine and supplies working oil to the hydraulic actuators, and the like are arranged. The electric excavator may have a storage battery instead of the engine, drive an electric motor with electric power stored in the storage battery, and operate a hydraulic pump using the driving force of the electric motor.

A handrail 19 is provided in front of the engine room 9 in the revolving body 3 . An antenna 21 is provided on the handrail 19 . Antenna 21 is, for example, a GNSS antenna. The antenna 21 has a first antenna 21A and a second antenna 21B provided on the revolving body 3 so as to be separated from each other in the horizontal direction.

The work machine 2 is mounted on the revolving body 3 and supported by the revolving body 3 . The work implement 2 has a boom 6 , an arm 7 and a bucket 8 . The boom 6 is rotatably connected to the revolving body 3 . Arm 7 is rotatably connected to boom 6 . Bucket 8 is rotatably connected to arm 7 . Bucket 8 has a plurality of blades. A tip portion of the bucket 8 is referred to as a cutting edge 8a.

It should be noted that the bucket 8 may not have blades. The tip of the bucket 8 may be formed of a straight steel plate.

The base end of the boom 6 is connected to the revolving body 3 via a boom foot pin 13 (hereinafter referred to as "boom pin"). A base end portion of the arm 7 is connected to a tip end portion of the boom 6 via an arm connection pin 14 (hereinafter referred to as an arm pin). The bucket 8 is connected to the tip of the arm 7 via a bucket connecting pin 15 (hereinafter referred to as bucket pin).

The boom 6 is movable relative to the revolving body 3. The boom 6 is rotatable relative to the revolving body 3 around the boom pin 13 . The boom pin 13 is provided on the revolving body 3 . The boom pin 13 forms a reference point that serves as a reference for relative movement of the work implement 2 with respect to the revolving body 3 . Arm 7 is relatively movable with respect to boom 6 . The arm 7 is rotatable relative to the boom 6 around the arm pin 14 . Bucket 8 is relatively movable with respect to arm 7 . Bucket 8 is rotatable relative to arm 7 around bucket pin 15 .

The arm 7 and the bucket 8 are integrally movable relative to the boom 6, specifically rotatable relative to each other, while the bucket 8 does not rotate relative to the arm 7. The boom 6, the arm 7 and the bucket 8 are integrally movable relative to the revolving structure 3 while the bucket 8 does not rotate relative to the arm 7 and the arm 7 does not rotate relative to the boom 6. , specifically relatively rotatable.

The boom 6 of the work machine 2 rotates around the boom pin 13 provided at the base end of the boom 6 with respect to the revolving body 3 . A locus along which a specific portion of the boom 6 that rotates relative to the revolving body 3, such as the tip of the boom 6, moves is arcuate. A plane containing the arc is identified as the motion plane P shown in FIG. The action plane P is a plane that extends in the vertical direction and in the front-rear direction. The operation plane P is a plane that is located at the center of the work machine 2 in the left-right direction, includes the center axis of the revolving body 3, and extends in the up-down direction and the front-rear direction. The boom pin 13, the arm pin 14, and the bucket pin 15 extend in a direction perpendicular to the plane of motion P, that is, in the left-right direction. The plane of operation P is orthogonal to at least one (all three in the embodiment) of the axis of each of the boom 6 , the arm 7 and the bucket 8 .

The boom 6 rotates with respect to the revolving body 3 on the operation plane P. Similarly, the arm 7 rotates relative to the boom 6 on the plane P of motion, and the bucket 8 rotates relative to the arm 7 on the plane P of motion. The work machine 2 of the embodiment operates on the action plane P in its entirety in its longitudinal direction. The cutting edge 8a of the bucket 8 moves on the action plane P. As shown in FIG. The action plane P is a plane that includes the movable range of the work implement 2 . A plane of motion P intersects each of boom 6 , arm 7 and bucket 8 . The plane of motion P can be set at the center of the boom 6, the arm 7 and the bucket 8 in the lateral direction.

As shown in FIG. 1, one direction on the motion plane P is set as the X-axis, and a direction orthogonal to the one direction on the motion plane P is set as the Z-axis. The X-axis and Z-axis are orthogonal to each other. The setting of the coordinate axes on the motion plane P will be described later.

The working machine 2 has a boom cylinder 10 , an arm cylinder 11 and a bucket cylinder 12 . A boom cylinder 10 drives the boom 6 . Arm cylinder 11 drives arm 7 . Bucket cylinder 12 drives bucket 8 . Each of the boom cylinder 10, the arm cylinder 11, and the bucket cylinder 12 is a hydraulic cylinder driven by hydraulic fluid.

The work machine 2 constitutes a link mechanism in which a plurality of link members are connected via joints. The boom 6, arm 7 and bucket 8 each constitute a link member. The boom pin 13 corresponds to a joint that connects the revolving body 3 and the boom 6 . Arm pin 14 corresponds to a joint that connects boom 6 and arm 7 . Bucket pin 15 corresponds to a joint that connects arm 7 and bucket 8 .

The bucket cylinder 12 is attached to the arm 7. The bucket 8 rotates with respect to the arm 7 by expanding and contracting the bucket cylinder 12 . The work machine 2 has a bucket link. The bucket link connects the bucket cylinder 12 and the bucket 8 .

A controller 26 is mounted on the hydraulic excavator 100 . The controller 26 controls operations of the excavator 100 . The controller 26 is a computer including a CPU (Central Processing Unit), a nonvolatile memory, a timer, and the like.

FIG. 2 is a side view of hydraulic excavator 100 shown in FIG. As shown in FIG. 2, the excavator 100 further includes a boom IMU (Inertial Measurement Unit) 32, an arm IMU 33, and a bucket IMU . Boom IMU 32, arm IMU 33, and bucket IMU 34 are inertial measurement units.

The boom IMU 32 is attached to the boom 6. Arm IMU 33 is attached to arm 7 . Bucket IMU 34 is attached to bucket 8 . The boom IMU 32, the arm IMU 33, and the bucket IMU 34 respectively detect the acceleration of the boom 6, the arm 7, and the bucket 8 in the longitudinal, lateral, and vertical directions, and the acceleration of the boom 6, the arm 7, and the bucket in the longitudinal, lateral, and vertical directions. 8 angular velocities are measured.

The angle of the boom 6 is calculated from the detection result of the boom IMU 32. The angle of arm 7 is detected from the detection result of arm IMU 33 . The angle of the bucket 8 is calculated from the detection result of the bucket IMU 34 . Boom IMU 32, arm IMU 33, and bucket IMU 34 constitute an angle sensor that measures the attitude of work implement 2 with respect to revolving body 3 (the vehicle body of hydraulic excavator 100).

The boom IMU 32 detects the attitude (angle) of the boom 6 with respect to the direction of gravity. Arm IMU 33 detects the posture (angle) of arm 7 with respect to the direction of gravity. Bucket IMU 34 detects the attitude (angle) of bucket 8 with respect to the direction of gravity.

The angle sensor may include any other sensor in addition to each IMU described above. The angle sensor uses a cylinder stroke sensor attached to the boom cylinder 10, the arm cylinder 11 or the bucket cylinder 12 that detects the amount of displacement of the cylinder rod with respect to the cylinder. 7. Alternatively, the posture (angle) of the bucket 8 may be obtained. The angle sensor may be a potentiometer or rotary encoder attached to boom pin 13 , arm pin 14 or bucket pin 15 . A detection result of the angle sensor is input to the controller 26 (FIG. 1).

The distance bm shown in FIG. 2 is the distance between the boom pin 13 and the arm pin 14. The distance bm is also called the link length of the boom 6 . A distance am is the distance between the arm pin 14 and the bucket pin 15 . Distance am is also referred to as the link length of arm 7 . The distance cm is the distance between the bucket pin 15 and the cutting edge 8 a of the bucket 8 . The distance cm is also called the link length of the bucket 8 .

FIG. 3 is a flow diagram showing the flow of processing for calibrating information regarding the hydraulic excavator 100. FIG. Details of the process of calibrating the information about the hydraulic excavator 100 will be described below with appropriate reference to FIG. 3 and subsequent figures. The process of calibrating information about the excavator 100 may be executed by the controller 26 mounted on the excavator 100, or may be executed by an external controller or information processing device. When an externally provided controller executes processing for calibrating information related to the hydraulic excavator 100, the controller 26 mounted on the hydraulic excavator 100 transmits the detection result of the angle sensor to the external controller.

The information about the hydraulic excavator 100 calibrated by the following processing is used to accurately derive the position of the cutting edge 8a of the bucket 8 and improve the accuracy of the calculation of the position of the work implement 2 when performing information-aided construction. It is necessary information. Information about the excavator 100 to be calibrated includes, for example, the dimensions of the work implement 2 of the excavator 100 . The distance bm, distance am, and distance cm are included in the information about the work machine. The information about the excavator 100 may be position coordinate information of a predetermined portion of the excavator 100 in a three-dimensional space, distance information between two predetermined portions, and the like. The coordinate system of the three-dimensional space may be the ITRF (International Terrestrial Reference Frame) coordinate system.

First, in step S0, a measurement target is set. A measurement target is set at one location on the work implement 2 of the hydraulic excavator 100 . Among the plurality of link members of the work machine 2 , the bucket 8 is the tip link member that is farthest from the revolving body 3 . A measurement target is set at one point of the bucket 8 which is a link member at the tip. In the embodiment, the cutting edge 8a of the bucket 8 is set as the measurement target.

In step S1, the cutting edge 8a of the bucket 8 is aligned with the measurement point A1. FIG. 4 is a schematic side view showing the operation of aligning the cutting edge 8a of the bucket 8 with the measurement point A1. By moving the working machine 2, the cutting edge 8a of the bucket 8 is brought into contact with the ground or the like. The working machine 2 is stopped in that posture. The position of the cutting edge 8a at that time is defined as a measurement point A1. In step S1, the cutting edge 8a, which is the measurement target, is moved to the measurement point A1.

In step S2, with the cutting edge 8a of the bucket 8 stopped at the measurement point A1, the angle of each link member of the working machine 2 detected by each angle sensor is acquired. The angle of the boom 6 is detected by the boom IMU 32, the angle of the arm 7 is detected by the arm IMU 33, and the angle of the bucket 8 is detected by the bucket IMU 34 when the cutting edge 8a of the bucket 8 is at the measurement point A1. As a result, the posture of the working machine 2 with respect to the revolving body 3 is measured while the cutting edge 8a is stopped at the measuring point A1.

In step S3, the cutting edge 8a of the bucket 8 is aligned with the measurement point A2. FIG. 5 is a schematic side view showing the operation of aligning the cutting edge 8a of the bucket 8 with the measurement point A2. By moving the working machine 2, the cutting edge 8a of the bucket 8 is brought into contact with the ground or the like at a position different from the measurement point A1. In the example shown in FIG. 5, the cutting edge 8a is moved forward (in the direction away from the vehicle body) and brought into contact with the ground at a position forward of the measurement point A1. The working machine 2 is stopped in that posture. The position of the cutting edge 8a at that time is defined as a measurement point A2. In step S3, the cutting edge 8a, which is the measurement target, is moved from the measurement point A1 to the measurement point A2 different from the measurement point A1. In the example shown in FIG. 5, the boom 6 is lowered and the arm 7 and the bucket 8 are moved forward.

In step S4, the X direction is set. As shown in FIG. 5, the direction connecting the measurement points A1 and A2 is set as the X-axis on the motion plane P. As shown in FIG. The positions of the measurement points A1 and A2 in the vertical direction may be the same, and in this case the X direction is the horizontal direction.

In step S5, with the cutting edge 8a of the bucket 8 stopped at the measurement point A2, the angle of each link member of the working machine 2 detected by each angle sensor is obtained. The angle of the boom 6 is detected by the boom IMU 32, the angle of the arm 7 is detected by the arm IMU 33, and the angle of the bucket 8 is detected by the bucket IMU 34 when the cutting edge 8a of the bucket 8 is at the measurement point A2. As a result, the posture of the working machine 2 with respect to the revolving body 3 is measured while the cutting edge 8a is stopped at the measuring point A2.

In step S6, the distance between the measurement points A1 and A2 is measured. This distance measurement may be performed using an inexpensive length measuring device such as a laser length measuring device. A measurement result of the length measuring device may be input to a controller that executes a process of calibrating information regarding the hydraulic excavator 100 . When a length measuring device is used, a reflector that reflects laser light may be attached to the cutting edge 8a of the bucket 8, which is the measurement target, and a marker may be provided to facilitate recognition of the position. When a reflector that reflects laser light is used as the measurement target, the reflector reflects light in the same direction as the direction in which the laser light is emitted. Alternatively, the operator may manually measure the distance using a wire-type length measuring device, a tape measure, or the like. The operator may manually input the measurement results into the controller.

In the processing of steps S1 to S5, the cutting edge 8a of the bucket 8 is brought into contact with the ground, but by attaching a water thread to the cutting edge 8a of the bucket 8 and hanging it, the X direction is set without contacting the cutting edge 8a with the ground. is also possible.

In step S7, the cutting edge 8a of the bucket 8 is aligned with the measurement point A3. FIG. 6 is a schematic side view showing the operation of aligning the cutting edge 8a of the bucket 8 with the measurement point A3. By moving the working machine 2, the cutting edge 8a of the bucket 8 is moved above the measurement points A1 and A2. The working machine 2 is stopped in that posture. The position of the cutting edge 8a at that time is defined as a measurement point A3. In step S7, the cutting edge 8a, which is the measurement target, is moved to a measurement point A3 different from the measurement points A1 and A2 on the plane containing the measurement points A1 and A2. In the example shown in FIG. 6, the boom 6 is raised and the arm 7 and bucket 8 are moved backward.

At least three different measurement points are set on the operation plane P shown in FIG. Measurement points A1, A2, and A3 are set on an operation plane P, which is a plane. The measurement points A1, A2, A3 form a triangle with each point as the vertex. FIG. 6 shows an example in which the measurement point A3 is between the measurement points A1 and A2 in the front-rear direction (horizontal direction in the drawing). , or may be further away from the vehicle body than the measurement point A2.

In step S8, the Z direction is set. As shown in FIG. 6, the direction of the perpendicular drawn from the measuring point A3 to the straight line connecting the measuring points A1 and A2 is set as the Z-axis on the operating plane P. As shown in FIG. If the X direction is horizontal, the Z direction is up and down. The measurement point A1 is set as the origin, the direction connecting the measurement points A1 and A2 is set as the X axis, and the direction perpendicular to the X axis is set as the Z axis. Thereby, a measurement coordinate system is defined on the operation plane P. FIG.

In step S9, with the cutting edge 8a of the bucket 8 stopped at the measurement point A3, the angle of each link member of the working machine 2 detected by each angle sensor is acquired. The angle of the boom 6 is detected by the boom IMU 32, the angle of the arm 7 is detected by the arm IMU 33, and the angle of the bucket 8 is detected by the bucket IMU 34 when the cutting edge 8a of the bucket 8 is at the measurement point A3. As a result, the posture of the working machine 2 with respect to the revolving body 3 is measured while the cutting edge 8a is stopped at the measuring point A3.

In step S10, the distance between measurement points A1 and A3 is measured, and the distance between measurement points A2 and A3 is measured. This distance measurement may be performed using an inexpensive length-measuring device, or may be performed manually, as in step S6.

In step S11, the measurement coordinates of the measurement point A3 are set. Let the X coordinate of the measurement point A3 be the distance from the point where the X axis intersects with the perpendicular drawn from the measurement point A3 to the measurement point A1 (origin). The Z coordinate of the measurement point A3 is defined as the length between two points, starting from the measurement point A3 and ending at the point at which the perpendicular to the X axis intersects the X axis. The distance between the measurement points A1 and A2 measured in step S6, the distance between the measurement points A1 and A3 measured in step S10, and the distance between the measurement points A2 and A3 is used to calculate the cosine of the angle between the straight line connecting the measurement points A1 and A3 and the X-axis by the cosine theorem, and from this cosine and the distance between the measurement points A1 and A3, the measurement point A3 may be obtained. The sine of the angle between the straight line connecting the measurement points A1 and A3 and the X-axis is calculated by the trigonometric ratio formula, and the distance between the measurement points A1 and A3 is used to calculate the angle of the measurement point A3. A Z coordinate may be determined. According to the number of coordinates (parameters) to be obtained, the work machine 2 is operated to move the cutting edge 8a to a position other than the measurement points A1, A2, and A3, and the information calibration method shown in this embodiment is used to determine each coordinate. Calculation should be performed.

In step S12, the initial values of the information used to calculate the calculated coordinates of the measurement points are entered. The information used to calculate the calculated coordinates of the measurement points is the X coordinate Xbf of the boom pin 13, the Z coordinate Zbf of the boom pin 13, the link length bm of the boom 6, the link length am of the arm 7, the link length cm of the bucket 8, the link length cm of the arm 7, The offset value αof for the output value α of the arm IMU 33 that detects the angle, the offset value βof for the output value β of the boom IMU 32 that detects the angle of the boom 6, and the offset value βof for the output value C of the bucket IMU 34 that detects the angle of the bucket 8. value Cof.

FIG. 7 is a schematic side view showing the coordinates of the boom pin 13. FIG. With the method described above, the X-axis and Z-axis are set with the measurement point A1 as the origin. The X coordinate Xbf of the boom pin 13 is the distance in the X direction (horizontal direction, for example) between the boom pin 13 and the measurement point A1. The Z coordinate Zbf of the boom pin 13 is the distance in the Z direction (for example, vertical direction) between the boom pin 13 and the X axis (for example, the ground). The design value of the dimension from 13 to the lower surface of crawler belt 5Cr may be used as the initial value. A design value is a dimension of each part determined for manufacturing the hydraulic excavator 100 .

Design values can be used for the initial values of the link length bm of the boom 6, the link length am of the arm 7, and the link length cm of the bucket 8. The initial values of the angle sensor offset values αof, βof, and Cof may be zero. These initial values are input to a controller that executes processing for calibrating information about the excavator 100 . An automatic input from the length measuring device to the controller may be performed, or a manual input to the controller may be performed. The controller may have an information storage section for storing information, and part or all of the information, such as the design value of the link length, may be stored in advance in the information storage section.

Using the output value α of the arm IMU 33, the output value β of the boom IMU 32, and the initial values of each information used to calculate the calculated coordinates of the measurement point, the X coordinate Xat of the arm pin 14 is expressed by the following equation (1): Calculate with

The Z coordinate Zat of the arm pin 14 is calculated by the following formula (2).

Using the Xat calculated by Equation (1), the output value C of the bucket IMU 34, and the initial values of each information, the X coordinate Xtt of the cutting edge 8a of the bucket 8, which is the measurement target, is calculated by the following Equation (3): Calculate with

The Z coordinate Ztt of the cutting edge 8a of the bucket 8 is calculated by the following formula (4) using the Zat calculated by the formula (2), the output value C of the bucket IMU 34, and the initial values of each information.

In the description of this embodiment, the case where there are three measurement points will be described, but as will be described later, there may be three or more measurement points. Therefore, the number of measurement points is n, and the following description will be made using mathematical formulas. Measurement coordinates are obtained for n measurement points, and calculated coordinates of the measurement target corresponding to those measurement points are calculated. The n calculated coordinates can be expressed using a matrix, as in Equation (5).

Also, the measurement coordinates for the n measurement points can be expressed using a matrix as shown in Equation (6).

In step S13, each piece of information about the working machine 2 is derived by the method of least squares. As described above, the derived information includes the X coordinate Xbf of the boom pin 13, the Z coordinate Zbf of the boom pin 13, the link length bm of the boom 6, the link length am of the arm 7, the link length cm of the bucket 8, and the angle of the arm 7. The offset value αof for the output value α of the arm IMU 33 to be detected, the offset value βof for the output value β of the boom IMU 32 for detecting the angle of the boom 6, and the offset value Cof for the output value C of the bucket IMU 34 for detecting the angle of the bucket 8. is.

Information related to the work implement 2 is derived so as to minimize the difference between the measured coordinates Ptt of the measurement point given by Equation (6) and the calculated coordinates P ^* tt of the measurement point given by Equation (5). For example, as described in the reference (Soichi Ibaraki, "Spatial Accuracy of Machine Tools, Geometric Model, Correction, and Measurement of 3D Motion Error", Morikita Publishing, April 2017), the Newton method was used. By applying the nonlinear least-squares method, it is possible to simultaneously derive each piece of information including the length of the link member of the working machine 2 and the offset value of the angle sensor.

Finally, in step S14, the information is updated. The initial value of the information about the work machine 2 stored in the information storage unit of the controller is overwritten with the value derived in step S13 to update the information about the work machine 2 . In this way, a series of processes for calibrating the information on the hydraulic excavator 100 is completed (“END” in FIG. 3). In this embodiment, the measurement coordinate system is specified in steps S4 and S8, but the measurement coordinates of the measurement points may be obtained based on the distances of the measurement points without specifying the measurement coordinate system.

Although there are some descriptions that overlap with the above description, the characteristic configuration and effects of this embodiment are summarized below.

In the information calibration method according to the embodiment, in steps S1, S3, and S7 shown in FIG. 3, the cutting edge 8a, which is the measurement target, is sequentially stopped at the measurement points A1, A2, and A3. In steps S2, S5, and S9, the posture of the work implement 2 with respect to the vehicle body is measured while the cutting edge 8a is stopped at each of the measurement points A1, A2, and A3. In steps S6 and S10, the distances between the measurement points A1, A2 and A3 are measured. In step S13, information for minimizing the difference between the measurement coordinates of the measurement points based on the distance between the measurement points and the calculated coordinates of the measurement points calculated using the attitude of the work machine 2 and the information on the work machine is obtained. derive In step S14, information is updated.

　In order to measure the distance between the measurement points A1, A2, and A3, there is no need to use an expensive automatic tracking type length measuring device. Distances may be measured manually, and can be done inexpensively anywhere with any tool for measuring length. The distance between these measurement points can be used to calibrate information about the work machine. Therefore, according to the information calibrating method of the embodiment, it is possible to calibrate the information about the working machine easily at low cost. It is also possible to redo the calibration at the construction site. Based on this calibrated information, the position of the cutting edge 8a of the bucket 8 can be accurately derived, so the accuracy of calculating the position of the working machine 2 in information-aided construction can be improved.

As shown in FIGS. 1 and 2, the work machine 2 has a revolving structure 3 and a boom 6 connected via a boom pin 13, a boom 6 and an arm 7 connected via an arm pin 14, and an arm 7 and a bucket. 8 are connected via a bucket pin 15. Information calibrated by the information calibration method of the embodiment includes the distance between boom pin 13 and arm pin 14 and the distance between arm pin 14 and bucket pin 15 . From this distance information, the link length bm of the boom 6 and the link length am of the arm 7 shown in FIG. 2 can be calibrated appropriately. Since it is not necessary to directly measure the position of each pin by attaching a survey target to the position of each pin in order to calculate the dimensions of the working machine 2, it is possible to measure the working machine 2 of the hydraulic excavator 100 by a short and simple work. Dimensional information can be obtained accurately.

As shown in FIG. 4, the measurement target is set on the bucket 8, which is the tip link member of the plurality of link members. Information calibrated by the information calibrating method of the embodiment includes the position of the cutting edge 8a, which is the measurement target, and the distance between the bucket pin 15. FIG. From this distance information, the link length cm of the bucket 8 shown in FIG. 2 can be calibrated appropriately.

As shown in FIG. 2, the hydraulic excavator 100 further has a boom IMU 32, an arm IMU 33, and a bucket IMU 34. Boom IMU 32 , arm IMU 33 , and bucket IMU 34 function as angle sensors that measure the attitude of work implement 2 . Information calibrated by the information calibration method of the embodiment includes offset values for output values of boom IMU 32 , arm IMU 33 and bucket IMU 34 . This allows the angle sensor to be properly calibrated.

As shown in FIGS. 1 and 2, the revolving body 3 of the hydraulic excavator 100 is provided with a boom pin 13 that serves as a reference point for relative movement of the work implement 2 with respect to the revolving body 3 . Information calibrated by the information calibrating method of the embodiment includes the X coordinate Xbf of the boom pin 13 and the Z coordinate Zbf of the boom pin 13 in the coordinate system defined on the operation plane P. This allows the position of the boom pin 13 to be properly calibrated.

As shown in FIG. 3, the information calibration method of the embodiment further comprises a step S4 of setting the X-axis on the motion plane P, which is a plane, and a step S8 of setting the Z-axis on the motion plane P. there is By setting a coordinate system based on the measurement points A1, A2, and A3 as shown in FIGS. , information about the work machine can be calibrated.

As shown in FIGS. 4 and 5, the measurement point A1 is set as the origin on the operation plane P, and the direction connecting the measurement points A1 and A2 is set as the X axis on the operation plane P. This makes it possible to easily set the X axis. As shown in FIG. 6, the direction orthogonal to the X-axis can be set as the Z-axis, thereby easily setting the XZ orthogonal coordinate system.

In the above description of the embodiment, an example was described in which three measurement points A1, A2, and A3 are set on the motion plane P, which is a plane. A larger number of measurement points may be set on the same plane. For example, the blade edge 8a of the bucket 8 may be brought into contact with the ground or the like at one or more positions between the measurement points A1 and A2, and the position of the blade edge 8a at that time may be used as the measurement point. The blade edge 8a of the bucket 8 may be moved to one or more positions above the measurement points A1 and A2 and different from the measurement point A3, and the position of the blade edge 8a at that time may be used as the measurement point. By increasing the number of measurement points, derivation of information about the hydraulic excavator 100 that minimizes the difference between the measured coordinates and the calculated coordinates of the measurement points can be performed more accurately.

The value of the angle sensor may be obtained multiple times while the cutting edge 8a of the bucket 8 is stopped at each measurement point. The cutting edge 8a at the tip of the working machine 2 may drop naturally due to deviation due to backlash of each link member of the working machine 2, minute leakage peculiar to the hydraulic system, or the like. For example, before measuring the distance in step S6, the angle sensor value is acquired in step S5, and after the distance is measured, the angle sensor value is acquired again to confirm that there is no difference in the angle sensor value. It may have functions.

In the description of the above embodiments, the hydraulic excavator 100 is given as an example of a working machine, but the excavator is not limited to the hydraulic excavator 100, and other types of work such as loading excavators, mechanical rope excavators, electric excavators, bucket cranes, etc. It is also applicable to machines.

The embodiments disclosed this time should be considered illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all changes within the meaning and scope equivalent to the scope of the claims.

1 Main body, 2 Work machine, 3 Rotating body, 5 Running body, 6 Boom, 7 Arm, 8 Bucket, 8a Cutting edge, 10 Boom cylinder, 11 Arm cylinder, 12 Bucket cylinder, 13 Boom foot pin, 14 Arm connecting pin, 15 Bucket connecting pin, 26 Controller, 32 Boom IMU, 33 Arm IMU, 34 Bucket IMU, 100 Hydraulic excavator, A1, A2, A3 Position, P Motion plane, RX Pivot axis.

Claims

An information calibrating method for calibrating information about a working machine, comprising a vehicle body and a working machine that is relatively movable with respect to the vehicle body, wherein a measurement target is set on the working machine, the method comprising:
sequentially stopping the measurement target at at least three different measurement points on a plane;
measuring the posture of the working machine with respect to the vehicle body while the measurement target is stopped at each of the measurement points;
measuring the distance between each of the measurement points;
minimizing the difference between the measured coordinates of the measurement point based on the distance and the calculated coordinates of the measurement point calculated using the orientation and the information in a coordinate system defined on the plane; deriving information and updating said information.
The work machine has a link mechanism in which a plurality of link members are connected via joints,
2. The information calibration method according to claim 1, wherein said information includes distances between a plurality of said joints.
The measurement target is set on the link member at the tip,
3. The method of calibrating information according to claim 2, wherein the information includes the distance between the position of the measurement target and the joint.
The working machine further has an angle sensor that measures the attitude,
4. The information calibration method according to any one of claims 1 to 3, wherein said information includes an offset value of said angle sensor.
The vehicle body is provided with a reference point that serves as a reference for relative movement of the working machine with respect to the vehicle body,
5. The information calibration method according to any one of claims 1 to 4, wherein said information includes coordinates of said reference point in said coordinate system.
The information calibration method according to any one of claims 1 to 5, further comprising setting the coordinate system on the plane.
The measurement points include a first measurement point and a second measurement point,
Setting the coordinate system includes setting the first measurement point as an origin and setting a direction connecting the first measurement point and the second measurement point as a coordinate axis. The information calibration method according to claim 6.