Method and measurement system for obtaining the correction amount of a tilt sensor

Abstract

This invention provides a method and measurement system for acquiring the correction amount of a tilt sensor installed on construction machinery. [Solution] A method for obtaining the correction amount of a tilt sensor placed on a rotatable rotating body is provided, wherein a sheet-like target with a detectable center position is attached to a measurement point set on the rotating body on which the tilt sensor is placed, the rotating body with the target attached is imaged by an imaging unit capable of identifying each pixel in the captured image, the input point on the image of the rotating body with the target is calculated as a search point corresponding to the coordinate system of a surveying instrument, a search is performed by the surveying instrument centered on the search point, the target is detected, the center position of the target is measured and the angle is measured, the tilt amount of the rotating body is calculated from the measured value, and the correction value of the tilt sensor is obtained based on the calculated tilt amount and the output value of the tilt sensor.

Description

Technical Field

[0001] The present invention relates to a method for acquiring a correction amount of an inclination sensor provided in a construction machine, and a measurement system.

Background Art

[0002] In the fields of civil engineering and construction, for example, hydraulic excavators are used as construction machines to perform ground leveling and paving. Operations of a hydraulic excavator include movement of the main body of the hydraulic excavator, and driving and rotation of the upper revolving structure, boom, arm, and bucket. The operations of the hydraulic excavator are performed by automatic control or semi-automatic control that assists the operator's operations. For the control of the hydraulic excavator, it is important to accurately grasp the position of the cutting edge of the bucket. Therefore, it is necessary to grasp the inclination angle of a rotating body that is connected by links such as the upper revolving structure, boom, arm, and bucket and is driven to rotate. The rotating body of the construction machine is provided with an inclination sensor that measures the amount of inclination of the rotating body.

[0003] Patent Document 1 discloses a method for calculating a correction amount of an inclination sensor provided in a construction machine. A plurality of measurement points are set on the rotating body of the construction machine on which the inclination sensor is arranged, and the measurement points are measured by a surveying instrument. The inclination angle of the rotating body is calculated from the measured values of the plurality of measurement points. The correction value of the inclination sensor is calculated based on the output value of the inclination sensor. With this method, the correction value of the inclination sensor can be calculated. From the correction value, the inclination sensor can be calibrated, and automatic operation can be performed with high accuracy.

Prior Art Literature

Patent Document

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The method described in Patent Document 1 uses the rotation center of each rotating body as a measurement point, resulting in a large number of measurement points, and also employs a non-prism method. Therefore, it suffers from the problem of being time-consuming and labor-intensive.

[0006] The structure of this disclosure has been made in view of the above-mentioned problems, and aims to provide a method and measurement system for acquiring the correction amount of a tilt sensor. [Means for solving the problem]

[0007] To solve the above problem, in one aspect of the present disclosure, a method for obtaining the correction amount of a tilt sensor is provided, which is a method for obtaining the correction amount of a tilt sensor arranged on a rotatable rotating body, wherein a sheet-like target, which is the object to be measured by a surveying instrument and whose center position can be detected, is attached to a plurality of measurement points set on the rotating body on which the tilt sensor is arranged, the rotating body on which the targets are attached is imaged by an imaging unit in which each pixel of the captured image can be identified, the input points on the image of the rotating body on which the targets are imaged are calculated as search points corresponding to the coordinate system of the surveying instrument, the surveying instrument performs a search centered on the search points, the targets are detected, the center position of the targets is measured by distance and angle, the tilt amount of the rotating body is calculated from the measured values ​​of the center positions of the plurality of targets, and the correction value of the tilt sensor is obtained based on the calculated tilt amount and the output value of the tilt sensor.

[0008] Furthermore, in a measurement system according to one aspect of this disclosure, a surveying machine having a telescope that emits range-measuring light, an angle-measuring unit that detects the direction of the telescope, a drive unit that changes the direction of the telescope, an imaging unit configured to capture an image of the area in front of the telescope and acquire an image, and configured to identify the position of each pixel in the image, and a calculation control unit, a measurement target of the surveying machine, which consists of at least one sheet-like target with a detectable center position attached to a rotating body, a tilt sensor provided on the rotating body, and a unit that calculates the position of each pixel on the image captured by the imaging unit in the coordinate system of the surveying machine. The system comprises an image processing unit and a calculation unit, wherein the image processing unit calculates an input point on the image in which the target is captured as a search point corresponding to the coordinate system of the surveying instrument, the calculation control unit drives the drive unit to cause the telescope to search for the target with the search point as the center, detect the target and measure the distance and angle of the center position of the target, and the calculation unit calculates the tilt amount of the rotating body from the measured values ​​of the center positions of the multiple targets, and calculates the correction amount of the tilt sensor from the output value of the tilt sensor and the tilt amount. [Effects of the Invention]

[0009] As is clear from the above explanation, we can provide a method and measurement system for obtaining the correction amount of a tilt sensor. [Brief explanation of the drawing]

[0010] [Figure 1] The schematic configuration of the measurement system is shown. [Figure 2] As an example of a measurement target, a hydraulic excavator is shown. Figure 2(A) is a side view of the hydraulic excavator. Figure 2(B) is a top view of the hydraulic excavator. [Figure 3] This is a control block diagram for the surveying equipment and terminals. [Figure 4] This is an explanatory diagram of the measurement method. [Figure 5] An example of a measurement point on a hydraulic excavator is shown. [Figure 6] This flowchart shows the processing flow for obtaining the correction amount from the tilt sensor. [Modes for carrying out the invention]

[0011] Hereinafter, specific embodiments of the configuration of this disclosure will be described with reference to the drawings. The embodiments are illustrative and not limiting to the invention, and not all features or combinations thereof described in the embodiments are necessarily essential to the invention. Furthermore, in the following descriptions of embodiments and modifications, the same components will be denoted by the same reference numerals, and redundant descriptions will be omitted as appropriate.

[0012] (Schematic configuration) Figure 1 shows a schematic configuration of the measurement system 1 according to the configuration of this disclosure. The measurement system 1 is mainly used in construction work machines having multiple rotating bodies. A hydraulic excavator 10 will be described as an example of a measurement target.

[0013] The measurement system 1 includes a surveying instrument 30, a sheet-shaped target 8, and an image processing unit 52 and a calculation unit 53 included in the terminal 50.

[0014] The surveying instrument 30 is a total station equipped with distance measurement, angle measurement, and automatic aiming (search) functions.

[0015] A surveying instrument 30 is positioned to the side of a hydraulic excavator 10, which is placed on a flat surface, using a tripod. The surveying instrument 30 has a base portion 2a mounted on a leveling device, a support portion 2b that rotates horizontally around a horizontal rotation axis H relative to the base portion 2a, and a telescope 2c that rotates vertically around a vertical rotation axis V at the center of the support portion 2b.

[0016] The surveying instrument 30 also has an imaging function that captures images in the sighting direction, and is configured so that the position of each pixel in the captured image can be identified.

[0017] A sheet-like target 8 is attached to the measurement point on the hydraulic excavator 10. Target 8 is the object of measurement for the surveying instrument 30, and the center position of target 8 (hereinafter, center O) is detectable. Target 8 is, as an example, a prism sheet.

[0018] At the time of measurement, an operator holds a terminal 50 to perform processing. The terminal 50 has a touch panel type display screen 51 that serves as both a display unit and an input unit. An image captured by a surveying instrument 30 is displayed on the display screen 51. When the image of a hydraulic excavator 10 captured by the surveying instrument 30 is displayed on the display screen 51, the operator lightly touches a measurement point on the image, that is, a target 8 on the image, with a fingertip. The actual position and direction relative to the surveying instrument 30 corresponding to the point or area touched on the display screen 51 are calculated. The surveying instrument 30 directs the collimation direction to that position, searches for the measurement target around that position, and detects the target 8. The surveying instrument 30 collimates the center O of the target 8, and performs distance measurement and angle measurement. The surveying instrument 30 sequentially repeats searching, collimation, distance measurement and angle measurement for all measurement points touched on the display screen 51.

[0019] From the measured values obtained by the surveying instrument 30 for a plurality of targets 8 affixed to a rotating body (the boom 14 as an example in FIG. 1) constituting a movable part of the hydraulic excavator, the length between the measurement points of the rotating body and the inclination amount are calculated. A correction value for the inclination sensor 6 can be acquired from the measurement value of the inclination sensor 6 provided on the rotating body and the inclination amount.

[0020] (Hydraulic Excavator) The details of the measurement system 1 will be described. FIG. 2 shows the hydraulic excavator 10. FIG. 2(A) is a side view of the hydraulic excavator 10. FIG. 2(B) is a top view of the hydraulic excavator 10. FIG. 3 is a control block diagram of the surveying instrument 30 and the terminal 50.

[0021] As shown in Figure 2, the hydraulic excavator 10 comprises a mobile unit 12 equipped with crawler tracks 11, an upper slewing body 13, a boom 14, an arm 15, and a bucket 16. The upper slewing body 13 is rotatable in the horizontal plane relative to the mobile unit 12 about a first pivot axis AX1. The boom 14 is rotatable vertically relative to the upper slewing body 13 about a second pivot axis AX2. The arm 15 is rotatable vertically relative to the boom 14 about a third pivot axis AX3. The bucket 16 is rotatable vertically relative to the arm 15 about a fourth pivot axis AX4.

[0022] The boom 14, arm 15, bucket 16, and upper slewing body 13, which are rotatable rotating parts, are each equipped with a first tilt sensor 6a, a second tilt sensor 6b, a third tilt sensor 6c, and a fourth tilt sensor 6d, respectively. Hereafter, unless otherwise specified, each tilt sensor will be collectively referred to as tilt sensor 6. The boom 14, arm 15, bucket 16, and upper slewing body 13 will be collectively referred to as rotating part B. The measurement system 1 is used to obtain the inter-axis dimensions, distance between set positions, tilt amount, and correction values ​​for calibrating the tilt sensors 6 of each rotating part B.

[0023] (Surveying machine 30) Figure 3 is a block diagram of the surveying instrument 30. As shown in Figure 3, the surveying instrument 30 comprises a surveying instrument communication unit 31, a distance measuring unit 32, a horizontal angle detector 33, a vertical angle detector 34, a horizontal rotation drive unit 35, a vertical rotation drive unit 36, a storage unit 37, an imaging unit 38, a surveying instrument input unit 41, a surveying instrument display unit 42, an automatic aiming unit 43, and a calculation control unit 39.

[0024] The surveying instrument communication unit 31 enables the transmission and reception of data with the terminal 50. Known wireless / wired communication methods can be used.

[0025] The distance measuring unit 32 is a known EDM (Electro Distance Meter). The distance measuring unit 32 comprises a light transmitting unit and a light receiving unit, sights the object to be measured, emits a distance measuring light onto the object, receives the reflected light reflected by the object with the light receiving unit, and measures the distance to the object from the phase difference or time difference between the distance measuring light and the internal reference light. The distance measuring unit 32 is located inside the telescope 2c, and the distance measuring optical system shares an optical axis with the sighting optical system of the telescope 2c.

[0026] The horizontal angle detector 33 and the vertical angle detector 34 are encoders. The horizontal angle detector 33 is mounted on the horizontal rotation axis H and detects the horizontal angle of the mounting section 2b. The vertical angle detector 34 is mounted on the vertical rotation axis V and detects the vertical angle of the telescope 2c.

[0027] The horizontal rotation drive unit 35 and the vertical rotation drive unit 36 ​​are motors. The horizontal rotation drive unit 35 rotates the mounting unit 2b around the horizontal rotation axis H. The vertical rotation drive unit 36 ​​rotates the telescope 2c around the vertical rotation axis V. The orientation of the telescope 2c is changed by the cooperation of both drive units.

[0028] The angle measuring unit is composed of a horizontal angle detector 33 and a vertical angle detector 34. The drive unit is composed of a horizontal rotation drive unit 35 and a vertical rotation drive unit 36.

[0029] The memory unit 37 is a storage medium, such as a hard disk drive, and stores a program for arithmetic control. Acquired measurement values ​​and calculated values ​​are also stored there.

[0030] The imaging unit 38 is a camera sensor, such as a CCD or CMOS sensor. The position of each pixel in the image captured by the imaging unit 38 can be determined. For example, the imaging unit 38 has a Cartesian coordinate system with the optical axis of the distance measuring light as the origin. Since the distance measuring optical axis of the surveying instrument 30 and the camera axis of the imaging unit 38 are coaxial, the corresponding positions can be calculated in each coordinate system. Other configurations, such as a depth camera, may be used as long as the position of each pixel in the image can be determined. The landscape captured by the imaging unit 38 is sent to the terminal 50 via the surveying instrument communication unit 31 and displayed on the display screen 51.

[0031] The surveying instrument input unit 41 and the surveying instrument display unit 42 are interfaces for the surveying instrument 30. They allow input of operations for the surveying instrument 30 and information and commands for the surveying instrument 30. Alternatively, the same functions may be provided to the terminal 50, which can be used as the operation terminal for the surveying instrument 30, allowing the surveying instrument 30 to be remotely controlled from the terminal 50.

[0032] The automatic aiming unit 43 includes at least an aiming optical system that shares a common axis with the distance measuring light, an aiming light source, and an image sensor such as a CMOS or CCD. The automatic aiming unit 43 emits aiming light from the aiming light source, receives the reflected aiming light from the measurement point with the image sensor, and performs automatic aiming to align the aiming light axis with the measurement point based on the received light result.

[0033] The arithmetic control unit 39 is a microcontroller mounted on a substrate, for example, with at least one processor (e.g., a CPU (Central Processing Unit)) and at least one memory (e.g., DRAM (Dynamic Random Access Memory), SRAM (Static Random Access Memory), etc.). The processor executes each control according to the stored program. The arithmetic control unit 39 is connected to and controls all the instruments of the surveying instrument 30. For example, it controls the horizontal rotation drive unit 35 and the vertical rotation drive unit 36, controls the emission of the distance measuring light of the distance measuring unit 32, automatic aiming, distance and angle measurement, and transmission and reception of information via the surveying instrument communication unit 31.

[0034] (50) The terminal 50 includes a terminal communication unit 54 capable of sending and receiving data with the surveying instrument 30, a display screen 51 that serves as both a display unit and an input unit, and a terminal control unit 59. The terminal control unit 59 has an image processing unit 52 and a calculation unit 53.

[0035] The image processing unit 52 calculates the specified pixels in the image captured by the imaging unit 38 in the coordinate system of the surveying instrument 30.

[0036] The calculation unit 53 performs various calculations based on the measured values ​​and acquired values ​​from each measurement point measured by the surveying instrument 30. For example, it calculates the distance between measurement points and the amount of inclination of the rotating body B of the hydraulic excavator 10. Furthermore, it calculates a correction value for the inclination sensor 6 from the calculated amount of inclination and the output value of the inclination sensor 6.

[0037] The display screen 51 is, for example, a touch panel display, and the operator can input data by touching or swiping on the display screen 51.

[0038] The terminal 50 is not limited to a dedicated terminal; each component may be installed as an application on a tablet or smartphone to perform the respective processing. The terminal 50 and the surveying instrument 30 may be integrated, and the processing of each component of the terminal 50 may be performed by the surveying instrument 30.

[0039] (target) Target 8 is, for example, a sheet-shaped prism, such as a perfect circle or a square. A sheet-shaped prism is a sheet-shaped or plate-shaped reflector. It has the characteristic of forming a reflective surface on its surface when small prisms are laid or when a reflective material is applied, and exhibiting retroreflection. Its outer shape is 180° point-symmetric with respect to the center point, and the center point is the center O. Even if a sheet prism with an outer shape of a circle or a square is tilted with respect to the sighting direction of the surveying instrument 30, the outer shape will become elliptical or rectangular. The surveying instrument 30 can detect the center O of Target 8 by scanning by moving the telescope 2c in the vertical and horizontal directions and determining the center position of the range in which reflected light is received. Alternatively, Target 8 may be a sheet prism with a configuration in which the reflectivity increases toward the center O. The center O can be detected from the amount of reflected light received. Target 8 is not limited to the above configuration, and other conventional configurations may be used as long as the center O can be detected. Target 8 is attached to the measurement point of the hydraulic excavator 10 with its center O aligned.

[0040] (Measurement method) The measurement method will be explained in detail. Figure 4(A) shows the display screen 51. Figure 4(B) shows the survey site. The measurement target will be a hydraulic excavator 10.

[0041] First, the surveying device 30 is positioned near the hydraulic excavator 10, and the hydraulic excavator 10 is imaged by the imaging unit 38. The image data is sent to the terminal 50, and the image captured by the imaging unit 38 is displayed on the display screen 51.

[0042] As shown in Figure 4(A), the operator touches the corresponding area in the image displayed on the display screen 51 to indicate the area to be measured using the surveying instrument 30 with the hydraulic excavator 10 (see also Figure 1). Since the display screen 51 is a touch panel, touch operation becomes an input operation. The touched point or area on the image is designated as an input point or input area. In this embodiment, a single point on the image is designated by touch. The designated point on the image is referred to as input point I.

[0043] The image processing unit 52 identifies the input point I on the image as its actual position and calculates it as a point (search point Q) in the coordinate system of the surveying instrument 30. This calculates the actual position and direction relative to the surveying instrument 30. In this embodiment, the horizontal azimuth angle and the vertical elevation or depression angle relative to the search point Q from the surveying instrument 30 are calculated.

[0044] As shown in Figure 4(B), the automatic aiming unit 43 directs its aiming direction towards the search point Q using the horizontal rotation drive unit 35 and the vertical rotation drive unit 36, and performs a search centered on the search point Q. The automatic aiming unit 43 moves the telescope 2c vertically and horizontally around the search point Q while illuminating it with aiming light, detects the target 8, and aims at the target 8. The surveying instrument 30 detects the center O of the target 8, aims at it, and performs distance and angle measurement.

[0045] Multiple input points can be specified at once by touching multiple locations on the image. The surveying instrument 30 searches for the first search point, sights it, and takes measurements, then begins searching for the next search point. Each search point Q becomes the center of the surveying instrument 30's search for the object to be measured.

[0046] Instead of the surveying instrument 30 measuring the distance and angle of the search point Q itself, which is calculated from the input point I, the surveying instrument 30 performs a search centered on the search point Q. The surveying instrument 30 moves the telescope 2c in the vertical and horizontal directions to change the sighting direction and search for the measurement target. Through the search of the surveying instrument 30, the target 8 attached to the measurement point is automatically detected.

[0047] Since the search is performed within a predetermined range centered on the search point Q, the operator does not need to precisely specify the point to be measured; they only need to input an approximate location by touching the display screen 51. For example, as shown in Figure 4, the point on the image touched by the operator and the search point Q are offset from the target 8, but the target 8 can be detected without any problems by the search performed by the automatic aiming unit 43. There is no need to precisely specify the measurement point with a pointer; simply touching the approximate location of the measurement point on the screen calculates the search point Q from the input point I, and the surveying instrument 30 searches around the search point Q to detect and measure the target 8. The input section of the terminal 50 is a touch panel type, making it easy for the operator to specify the measurement point on the displayed image and easy to operate intuitively.

[0048] The automatic aiming unit 43 can detect any object being measured by the surveying instrument 30 through a search. It is not limited to target 8; other surveying objects such as prisms can also be detected. Since target 8 is a sheet, it has a certain area. Therefore, the operator can easily identify and touch target 8 on the screen. Target 8 can also be easily detected by the surveying instrument 30's search function.

[0049] Furthermore, because the image sensor of the automatic aiming unit 43 has a field of view of several degrees, even if the touch position or direction is slightly off within this range, the object to be measured can be detected and aimed at. Needless to say, even if the object is outside the detection range of the image sensor, the object to be measured will be quickly detected by the search.

[0050] Since input points I can be set continuously, as shown in Figure 1, multiple targets 8 attached to the rotating body that constitutes the movable part of the hydraulic excavator can also be input continuously by touching them repeatedly. The calculation unit 53 calculates the distance between measurement points and the amount of inclination of the rotating body from the measurements taken by the surveying instrument 30. A correction value for the inclination sensor 6 can be obtained from the measurement value of the inclination sensor 6 provided on the rotating body and the amount of inclination.

[0051] The operator simply touches the measurement point on the display screen 51, and the correction value for the tilt sensor 6 is automatically calculated. This eliminates the need for the operator to perform measurements, making it easy to obtain the correction amount for the tilt sensor 6.

[0052] In this embodiment, a tablet with an integrated display unit and input unit is used. However, it is not limited to this configuration; the display unit and input unit may be separated, and the pointer may be moved using a mouse or key switch to input the input point I.

[0053] (Measurement point) The measurement point P to be measured by the surveying instrument 30 will be explained. Figure 5 illustrates an example of a measurement point P on the hydraulic excavator 10. The measurement point P can be changed as needed.

[0054] Measurement point Pa: First prism 5a located on the upper rotating body of hydraulic excavator 10 Measurement point Pb: Second prism 5b located in the IMU Measurement point Pc: Third prism 5c positioned on the pivot axis (AX1) Measurement point Pd: First target 8a located in the center of the width direction of boom 14 Measurement point Pe: Second target 8b located on the axis (AX2) of the boom pin. Measurement point Pf: Third target 8c located on the axis (AX3) of the arm pin. Measurement point Pg: Fourth target 8d located on the axis (AX4) of the bucket pin. Measurement point Ph: Fifth target 8e located on the axis of the first link pin. Measurement point Pi: The sixth target 8f, located on the axis of the second ring pin. Measurement point Pj: 8g of the 7th target located on the axis of the 3rd link pin. Measurement point Pk: 8th target 8h located at the center tip of the bucket. Measurement point Pl: 5th prism 5e located under the track In addition, the inclination of plane G can be calculated by measuring any point on the plane G where the hydraulic excavator 10 is positioned using a non-prism method.

[0055] Target 8 and prism 5 are the objects of measurement for the surveying instrument 30. Unless otherwise specified, the first to fifth prisms are collectively referred to as prism 5. Prism 5 is composed of retroreflectors such as corner cube prisms, and in this embodiment, it is a so-called omnidirectional prism that retroreflects light incident from all sides (360 degrees) in the direction opposite to the direction of incidence. Target 8, which is positioned on the axis, is attached to the end face exposed to the outside with its center O aligned with the axis center. Not limited to the above, known configurations can be used as long as they are the objects of measurement for the surveying instrument 30.

[0056] For example, the interaxial distance and tilt amount of the arm 15 are calculated from measurement points Pf and Pg. A correction value is calculated from the calculated tilt amount and the output value of the first tilt sensor 6a. This allows the first tilt sensor 6a to be calibrated.

[0057] From the measured values ​​at measurement point P, the inter-axis dimension, the length and inclination between predetermined positions can be calculated. Therefore, it can be used not only to obtain the correction amount for the tilt sensor 6, but also to calculate the offset amount between the tip of the bucket 16 and the first prism 5a from the inter-axis dimension and inclination, to correct the setting points necessary for controlling the hydraulic excavator 10, and to calibrate the equipment that drives the rotating body B, thereby improving the accuracy of the automatic control of the hydraulic excavator 10. Note that instead of the prism 5, a target 8 may be attached to each measurement point, or conversely, the prism 5 may be placed instead of the target 8.

[0058] The measurement values ​​at each measurement point P measured by the surveying instrument 30 are output to the calculation unit 53. The calculation unit 53 may be included in the calculation control unit 39 of the surveying instrument 30. Alternatively, the calculation unit 53 may be installed as an application along with the image processing unit 52 on the terminal 50 or the surveying instrument 30 to perform each process.

[0059] (Method for obtaining the correction amount) The method for obtaining the correction amount for the hydraulic excavator 10 using the measurement system 1 will be explained with reference to Figure 6. Figure 6 shows an example of the processing flow for obtaining the correction amount for the tilt sensor 6 in a construction work machine.

[0060] First, in step S01, the hydraulic excavator 10 is positioned on plane G. It is desirable that plane G is horizontal. Even if plane G is sloped, the slope can be calculated and corrected by measuring any three points on plane G. Furthermore, the surveying equipment 30 is set up on a tripod to the side of the hydraulic excavator 10.

[0061] Next, in step S02, the hydraulic excavator 10 is imaged by the imaging unit 38 of the surveying instrument 30. The image is taken so that the measurement points are included, i.e., the target 8 and prism 5 are visible. If all measurement points cannot be imaged at once, the images may be taken in multiple stages. The captured image is sent to the terminal 50.

[0062] Next, in step S03, the image captured in step S02 is displayed on the display screen 51.

[0063] Next, in step S04, the point to be measured (input point I) is specified on the image captured in step S02. The operator specifies input point I by touching the image of the hydraulic excavator 10 displayed on the display screen 51 (see Figure 4). There may be multiple input points I.

[0064] Next, in step S05, the position of input point I is calculated in the coordinate system of the actual surveying instrument. The image processing unit 52 identifies the corresponding position Q in the coordinate system of the surveying instrument from the input point I on the image. The calculated search point Q is sent to the surveying instrument 30.

[0065] Next, in step S06, the surveying instrument 30 performs a search centered on the search point Q, acquires targets 8 or prisms 5 placed at each measurement point, and performs distance and angle measurement.

[0066] Next, in step S07, if there is another search point Q, the process returns to step S06 and the same process is performed for the next search point Q. Once the process in step S06 is completed for all search points Q, the process proceeds to step S08.

[0067] Next, in step S08, the calculation unit 53 calculates the distance between axes and the inclination amount of the rotating part of the hydraulic excavator 10 from the measured values ​​taken by the surveying machine 30 in step S06.

[0068] Next, in step S09, the calculation unit 53 calculates the correction amount for the tilt sensor 6 from the tilt amount calculated in step S09 and the output value of the tilt sensor 6.

[0069] The tilt correction can also be calculated from the coordinates of three points on plane G and the coordinates of the first prism 5a. If the tilt of plane G is calculated from the coordinates of three points on plane G and the tilt correction is required because the tilt is greater than a predetermined value, the tilt correction is calculated and applied appropriately when calculating the inter-axis dimensions. The first prism 5a is positioned in a location where it does not rotate, and the tilt correction can be corrected from the height (z coordinate) of the first prism 5a. This allows for the calculation of a more accurate correction amount.

[0070] The correction amount for the tilt sensor 6 is automatically calculated by the calculation unit 53 from the measured values ​​obtained by the measurement system 1, which automatically measures the measurement points. This eliminates the need for the operator to measure the measurement points, making it easy to obtain the inter-axis dimensions of the upper slewing body 13, boom 14, arm 15, and bucket 16, as well as the correction amount for the tilt sensor 6. The calculated correction amount for the tilt sensor 6 can be used to calibrate the tilt sensor 6. It is also possible to measure the plane G on which the hydraulic excavator 10 is positioned using an inclinometer and compare it with the tilt amount of plane G calculated by the calculation unit 53. This allows for more accurate automatic control and operation assistance of the hydraulic excavator 10.

[0071] The embodiments described above are examples of the present invention, and these can be combined based on the knowledge of those skilled in the art; such combinations are also included within the scope of the present invention.

[0072] Some or all of the above embodiments may also be described as follows, but are not limited to the following: 1. A method for obtaining the correction amount of a tilt sensor placed on a rotatable rotating body, Multiple measurement points are set on the rotating body on which the tilt sensor is located, and sheet-like targets that are the object to be measured by the surveying instrument and whose center position can be detected are attached to these points. In an imaging unit where each pixel of the captured image can be identified, the rotating body to which the target is attached is imaged. The input point on the image of the rotating body in which the target is captured is calculated as a search point corresponding to the coordinate system of the surveying instrument. The surveying instrument performs a search centered on the search point, detects the target, and measures the distance and angle of the target's center position. From the measured values ​​of the center positions of the multiple targets, the tilt amount of the rotating body is calculated. A correction value for the tilt sensor is obtained based on the calculated tilt amount and the output value of the tilt sensor. A method for obtaining the correction amount of a tilt sensor, characterized by the above. 2. In the tilt sensor described in item 1 above, The image captured by the imaging unit is displayed on a touch panel display screen, and the input points are input on the display screen. How to obtain the correction amount from a tilt sensor. 3. A surveying instrument comprising: a telescope that emits rangefinder light; an angle measuring unit that detects the direction of the telescope; a drive unit that changes the direction of the telescope; an imaging unit configured to capture an image of the area in front of the telescope and acquire an image, and configured to specify the position of each pixel in the image; and a calculation control unit. The measurement target of the aforementioned surveying instrument is a sheet-like target, which is attached in multiple places to a rotating body and whose center position can be detected, A tilt sensor provided on the rotating body, An image processing unit calculates the position of each pixel on the image captured by the imaging unit in the coordinate system of the surveying instrument, Calculation unit, Equipped with, The image processing unit calculates the input points on the image in which the target is captured as search points corresponding to the coordinate system of the surveying machine, The calculation control unit drives the drive unit to cause the telescope to search for the target with respect to the search point, detect the target, and measure the distance and angle of the target's center position. The calculation unit calculates the tilt amount of the rotating body from the measured values ​​of the center positions of the multiple targets, and calculates the correction amount of the tilt sensor from the output value of the tilt sensor and the tilt amount. A measurement system characterized by the following features. [Explanation of Symbols]

[0073] 1: Measurement System 2c: telescope 6: Tilt sensor 8: Target 30:Surveying machine 32: Distance measurement section 33: Horizontal angle detector (angle measuring unit) 34: Vertical angle detector (angle measuring unit) 35: Horizontal rotation drive unit (drive unit) 36: Vertical rotation drive unit (drive unit) 38: Imaging Unit 39: Calculation Control Unit 50: Terminal 51:Display screen 52: Image Processing Unit 53: Calculation section B: Rotating body I: Input point O: Center P:Measurement point Q: Search point S01~S09: Steps

Claims

1. A method for obtaining the correction amount of a tilt sensor placed on a rotatable rotating body, Multiple measurement points are set on the rotating body on which the tilt sensor is located, and sheet-like targets that are the object to be measured by the surveying instrument and whose center position can be detected are attached to these points. In an imaging unit where each pixel of the captured image can be identified, the rotating body to which the target is attached is imaged. The input points on the image of the rotating body that have been captured are calculated as search points corresponding to the coordinate system of the surveying instrument. The surveying instrument performs a search centered on the search point, detects the target, and measures the distance and angle of the target's center position. From the measured values ​​of the center positions of the multiple targets, the tilt amount of the rotating body is calculated. A correction value for the tilt sensor is obtained based on the calculated tilt amount and the output value of the tilt sensor. A method for obtaining the correction amount of a tilt sensor, characterized by the above.

2. The image captured by the imaging unit is displayed on a touch panel display screen, and the input points are input on the display screen. A method for obtaining the correction amount of a tilt sensor according to feature 1.

3. A surveying instrument comprising: a telescope that emits range-measuring light; an angle-measuring unit that detects the direction of the telescope; a drive unit that changes the direction of the telescope; an imaging unit configured to capture an image of the area in front of the telescope and acquire an image, and configured to specify the position of each pixel in the image; and a calculation control unit. The measurement target of the aforementioned surveying instrument is a sheet-like target, which is attached in multiple places to a rotating body and whose center position can be detected, A tilt sensor provided on the rotating body, An image processing unit calculates the position of each pixel on the image captured by the imaging unit in the coordinate system of the surveying instrument, Calculation unit, Equipped with, The image processing unit calculates the input points on the image in which the target is captured as search points corresponding to the coordinate system of the surveying machine, The calculation control unit drives the drive unit to cause the telescope to search for the target with respect to the search point, detect the target, and measure the distance and angle of the target's center position. The calculation unit calculates the tilt amount of the rotating body from the measured values ​​of the center positions of the multiple targets, and calculates the correction amount of the tilt sensor from the output value of the tilt sensor and the tilt amount. A measurement system characterized by the following features.

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