Construction machine

Abstract

To provide a construction machine that can determine whether or not calibration of a scale factor of an angular velocity sensor is necessary without interrupting a work.SOLUTION: A construction machine 100 is equipped with an angular velocity sensor and an acceleration sensor (IMU 50a) attached to a front member 31, and a controller 60 calculating an attitude of the front member 31 using outputs of the angular velocity sensor and the acceleration sensor. The controller 60 calculates an integral value of an angular velocity detected by the angular velocity sensor while the front member 31 is moving as a first rotation angle θ1, calculates difference between angles detected by the acceleration sensor before and after the movement of the front member 31 as a second rotation angle θ2, and when deviation between the first rotation angle and the second rotation angle is equal to or greater than a predetermined value δ1, outputs to an alarm device 69 that correction of the scale factor of the angular velocity sensor is necessary.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a construction machine equipped with an angular velocity sensor. [Background technology]

[0002] Construction machinery, including hydraulic excavators, may be equipped with acceleration sensors and angular velocity sensors. For example, if an acceleration sensor and an angular velocity sensor are attached to a front member (e.g., a boom, arm, and attachment) that constitutes the working mechanism of a hydraulic excavator, the attitude angle of the front member can be calculated from the outputs of the acceleration sensor and the angular velocity sensor.

[0003] However, the scale factor (sensitivity) of angular velocity sensors can change over time. When the scale factor changes, an error occurs in the angular velocity calculated from the sensor output, which in turn causes an error in the amount of change in angle (angle of rotation) calculated by integrating the angular velocity. For this reason, when the scale factor changes, the angular velocity sensor must be calibrated to correct the scale factor.

[0004] Regarding the calibration of angular velocity sensors, Patent Document 1 discloses a vibrating gyro device equipped with a constant-angle forced rotation mechanism that forcibly rotates a vibrating gyro (angular velocity sensor) by a fixed angle. In this device, the constant-angle forced rotation mechanism forcibly rotates the vibrating gyro by a fixed angle under conditions where no angular velocity is applied to the moving body, and the rotation angle calculation result (integrated value of the angle) based on the vibrating gyro output at that time is compared with the actual rotation angle, and based on the difference, it is confirmed whether or not correction of the scale factor of the vibrating gyro is necessary and corrected. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 02-266213 Summary of the Invention [Problem to be solved by the invention]

[0006] However, with the device of Patent Document 1, it is necessary to stop work and rotate the vibration gyro by a fixed angle using a forced rotation mechanism just to check whether or not the scale factor needs to be corrected, which can reduce the work efficiency of the construction machinery.

[0007] An object of the present invention is to provide a construction machine that can determine whether or not calibration of the scale factor of an angular velocity sensor is necessary without interrupting work. [Means for solving the problem]

[0008] The present application includes multiple means for solving the above-mentioned problems. One example is a construction machine equipped with a work implement having multiple connected front members, an angular velocity sensor and an acceleration sensor attached to the front members, and a controller that calculates the posture of the front member using the outputs of the angular velocity sensor and the acceleration sensor. The controller calculates, as a first rotation angle, the integral value of the angular velocity detected by the angular velocity sensor while the front member is moving, and calculates, as a second rotation angle, the difference between the angles detected by the acceleration sensor before and after the movement of the front member. When the deviation between the first rotation angle and the second rotation angle is equal to or greater than a predetermined value, the controller outputs to an alarm device that correction of the scale factor of the angular velocity sensor is necessary. [Effects of the Invention]

[0009] According to the present invention, it is possible to determine whether or not calibration of the scale factor of an angular velocity sensor is necessary without interrupting work. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a side view schematically showing the appearance of a hydraulic excavator according to a first embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a controller 60 and its peripheral devices. [Figure 3] 10 is a flowchart showing the processing of a controller 60. [Figure 4] 4 is an explanatory diagram of changes in the operation flag, the angular velocity integral value, and the tilt angle that appear when the flow of FIG. 3 is executed. [Figure 5] FIG. 10 is a schematic configuration diagram of a correction necessity determination system according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] First Embodiment 1 is a side view showing a schematic view of the exterior of a hydraulic excavator, which is an example of a construction machine according to this embodiment. In the following, a hydraulic excavator equipped with a bucket as an attachment located at the tip of the front working mechanism will be described, but various attachments other than the bucket, such as a grapple, a breaker, or a lifting magnet, can be attached instead.

[0013] In FIG. 1, the hydraulic excavator 100 is equipped with a multi-joint front working mechanism 30 in which multiple front members (e.g., a boom 31, an arm 33, and a bucket 35) that are connected in series and each rotate vertically, and an upper rotating body 20 and a lower traveling body 10 that constitute the vehicle body.

[0014] The upper rotating body 20 is provided so as to be able to rotate relative to the undercarriage 10. The upper rotating body 20 is constructed by arranging each member on a rotating frame 21, and the rotating frame 21 that constitutes the upper rotating body 20 is able to rotate relative to the undercarriage 10. In addition, the base end of a boom 31, which is the base end of the front working mechanism 30, is attached to the front part of the upper rotating body 20 that constitutes the vehicle body so as to be able to rotate in the vertical direction, the base end of an arm 33 is supported at the tip of the boom 31 so as to be able to rotate in the vertical direction, and a bucket 35 is supported at the tip of the arm 33 so as to be able to rotate in the vertical direction.

[0015] The lower traveling body 10 includes a pair of crawlers 11a (11b) respectively wound around a pair of left and right crawler frames 12a (12b), and traveling hydraulic motors 13a (13b) (including reduction mechanisms not shown) that drive the crawlers 11a (11b). Note that, with regard to each component of the lower traveling body 10, only one of the pair of left and right components is shown and referenced, and the other component is not shown, with only the reference numeral in parentheses in the drawing.

[0016] The boom 31, arm 33, bucket 35, and lower traveling structure 10 are driven by hydraulic actuators, namely, a boom cylinder 32, an arm cylinder 34, and a bucket cylinder 36, and left and right traveling hydraulic motors 13a (13b), respectively. The upper rotating structure 20 is similarly driven by a hydraulic actuator, namely, a swing hydraulic motor 23, via a reduction mechanism 24, and performs a swing operation in either the left or right direction relative to the lower traveling structure 10.

[0017] A cab (operator's compartment) 25 is disposed on the rotating frame 21 that constitutes the upper rotating body 20. The cab 25 is equipped with operating levers (operating devices) for operating objects including the front working mechanism 30 (plurality of front members 31, 33, 35), the upper rotating body 20, and the lower traveling body 10. In addition, a hydraulic circuit system 41 is mounted on the upper rotating body 20, including an engine 22 as a prime mover, as well as a hydraulic pump that supplies hydraulic oil to multiple hydraulic actuators such as the boom cylinder 32, arm cylinder 34, bucket cylinder 36, swing hydraulic motor 23, and left and right traveling hydraulic motors 13a (13b).

[0018] (IMU50) IMUs (Inertial Measurement Units) 50a-50d are attached to the boom 31, arm 33, and bucket 35, which are front members that make up the front working mechanism 30, and to the upper rotating body 20. Note that while Fig. 1 illustrates an example in which the IMU 50c for the bucket 35 is attached to a component member (bucket link member) of the link mechanism that connects the bucket 35 to the tip of the arm 33, the IMU 50c can also be treated as being mounted on the bucket 35 based on design data, etc., of the hydraulic excavator.

[0019] IMUs 50a-50d are devices for detecting the three-dimensional inertial motion of the mounting targets 31, 33, 35, and 20, and each is equipped with an acceleration sensor and an angular velocity sensor (neither shown). The acceleration sensor can detect (calculate), for example, acceleration, tilt angle (direction of gravity), velocity, displacement, and translation, while the angular velocity sensor can detect (calculate), for example, angular velocity, angle, and rotational motion. The tilt angle measured by the acceleration sensor and the angle measured by the angular velocity sensor can be used as attitude data for each unit 31, 33, 35, and 20. Below, the acceleration sensors within IMUs a-50d are sometimes referred to with the subscript a, and the angular velocity sensors are sometimes referred to with the subscript v. The four IMUs 50a, 50b, 50c, and 50d are sometimes collectively referred to as IMU 50.

[0020] Each of the IMUs 50a to 50d may be assigned unique identification information. By adding the identification information to the detection data of each IMU 50 and outputting the data to the in-vehicle network, it is possible to identify which IMU 50 each of the multiple pieces of detection data transmitted over the in-vehicle network has generated.

[0021] A controller 60 and an alarm device 69 are mounted inside the cab 25.

[0022] The controller 60 is a computer that executes calculations and controls related to the hydraulic excavator 100 by using a processor such as a CPU to execute programs stored in a storage device such as a semiconductor memory. The controller 60 can, for example, calculate the attitudes of the front members 31, 33, 35 and the upper rotating body 20 using the output of the IMU 50, and execute processing to determine whether or not correction of the scale factor of the angular velocity sensor in the IMU 50 is required.

[0023] The storage device in the controller 60 may store excavation target surface data that defines the three-dimensional shape of the terrain to be developed by the hydraulic excavator 100. By using the position data of the hydraulic excavator 100, the attitude data of the work implement 30 and the upper rotating body 20, and the excavation target surface data, it is possible to calculate the distance between the toe of the bucket 35 located at the tip of the work implement 30 and the excavation target surface. The position data and orientation data of the hydraulic excavator 100 can be obtained by mounting multiple positioning antennas and receivers on the hydraulic excavator 100.

[0024] The notification device 69 is a device for notifying workers, including the operator, whether or not it is necessary to correct the scale factor of the angular velocity sensor in the IMU 50. The notification device 69 is, for example, a monitor, and can display the result of the determination as to whether or not the scale factor needs to be corrected, and positional relationship information (for example, the relative position and distance between the bucket 35 and the terrain surface (the current terrain or the excavation target surface)). In addition to the monitor, a speaker or a warning light can also be used as the notification device 69 that notifies whether or not correction is necessary.

[0025] 2 is a configuration diagram of an example of the controller 60 and its peripheral devices. Connected to the controller 60 are pressure sensors 73b-73d, 74b-74d that detect the drive pressure of the actuators 32, 34, 36 that drive the multiple front members 31, 33, 35, IMUs 50a-50d, and a monitor that serves as an alarm device 69. Like the IMUs 50a-50d in the figure, they may be connected via an in-vehicle network (e.g., CAN) 70. Functions that can be executed by a processor in the controller 60 are shown as blocks in the controller 60 in the figure.

[0026] In the following, correction of the angular velocity sensors of the IMUs 50a-50c mounted on the boom 31, arm 33, and bucket 35 will be described, and a description of correction of the IMU 50d of the upper rotating body 20 will be omitted.

[0027] The pressure sensors 73b-73d and 74b-74d are sensors for detecting the operating conditions of the front members 31, 33, and 35 (i.e., the IMUs 50a-50c). Specifically, the pressure sensors 73b-73d and 74b-74d used in this embodiment are a pressure sensor 73b that detects the rod-side pressure of the boom cylinder 32, a pressure sensor 74b that detects the bottom-side pressure of the boom cylinder 32, a pressure sensor 73c that detects the rod-side pressure of the arm cylinder 34, a pressure sensor 74c that detects the bottom-side pressure of the arm cylinder 34, a pressure sensor 73d that detects the rod-side pressure of the bucket cylinder 36, and a pressure sensor 74d that detects the bottom-side pressure of the bucket cylinder 36. Hereinafter, some or all of the pressure sensors 73b-73d and 74b-74d may be collectively referred to as pressure sensors 73 and 74.

[0028] In addition to the pressure sensors 73b-73d and 74b-74d, sensors for detecting the operating conditions of the front members 31, 33 and 35 (IMUs 50a-50c) may also be used that detect the amount of operation of an operating device for the front members 31, 33 and 35, or an operation signal (pilot pressure or voltage) for the flow control valve of the hydraulic cylinders 32, 34 and 36. That is, if the actuators 32, 34 and 36 (front members 31, 33 and 35) are operated using so-called electric levers, the voltage value output from the controller 60 as the operation signal for the flow control valve may be detected. Furthermore, each IMU 50 may also be used as a sensor for detecting the operating conditions of the front members 31, 33 and 35 (IMUs 50a-50c).

[0029] The controller 60 can function as an operating state estimation unit 61, a first rotation angle calculation unit 62, a second rotation angle calculation unit 63, and a correction necessity determination unit 64 by executing a program stored in a storage device using a processor.

[0030] The operating state estimation unit 61 estimates the operating state of each of the front members 31, 33, 35 (each IMU 50) based on the detection values ​​(outputs) of the pressure sensors 73, 74.

[0031] The first rotation angle calculation unit 62 calculates, as the first rotation angle θ1, the integral value of the angular velocity detected by the angular velocity sensor of the IMU 50 while a certain front member X is in operation. Note that the "certain front member X" here refers to any one of the multiple front members 31, 33, and 35. Furthermore, "during operation" here refers to the period from the start to the end of operation M of the certain front member X. Furthermore, the "IMU 50" here may include not only the IMU 50 installed on the certain front member X, but also IMUs 50 installed on other front members that operate in conjunction with operation M of the certain front member X (for example, IMUs 50b and 50c installed on the arm and bucket when the boom operates). In other words, when a certain front member X is operated, it may also include an IMU 50 that appears to move in inertial space in conjunction with the operation.

[0032] The second rotation angle calculation unit 63 calculates, as the second rotation angle θ2, the difference between the angles (e.g., tilt angles α and β described below) detected by the acceleration sensor of the IMU 50 before and after the motion M of the certain front member X. Note that the "certain front member X" and "motion M" here are the same as the certain front member X and motion M described above. The "IMU 50" here is the same IMU 50 used to calculate the first rotation angle θ1. Also, the "detected angle difference" here is the difference between the tilt angle detected by the acceleration sensor of the "IMU 50" at the start of motion M (preferably immediately before the start of motion M) (e.g., pre-motion tilt angle α described below) and the tilt angle detected by the acceleration sensor of the "IMU 50" at the end of motion M (preferably immediately after the end of motion M) (e.g., post-motion tilt angle β described below).

[0033] The correction necessity determination unit 64 determines whether or not correction of the scale factor of the angular velocity sensor of the IMU 50 is necessary based on the deviation (deviation) between the first rotation angle θ1 calculated by the first rotation angle calculation unit 62 and the second rotation angle θ2 calculated by the second rotation angle calculation unit 63, and outputs the determination result to the alarm device 69.

[0034] Here, the processing of the controller 60 will be explained with reference to FIGS.

[0035] 3 is a flowchart showing the processing of the controller 60. The processing according to this flowchart starts at a predetermined cycle (for example, every 10 milliseconds). Note that below, this "cycle" may be referred to as the "calculation cycle."

[0036] (Step S10) When the process starts, in step S10, the controller 60 uses the operating state estimation unit 61 to determine whether each IMU 50 is in an operating state based on the detection values ​​of the pressure sensors 73 and 74. An IMU 50 determined to be in an operating state has its flag (also referred to as an operating flag) set to 1, while an IMU 50 determined to be not in an operating state (i.e., stationary) has its flag set to 0. To determine whether each IMU 50 is in an operating state, for example, the minimum pressure value at which the rod side or bottom side of the corresponding hydraulic cylinder 32, 34, or 36 can be operated can be used. That is, if the detection value of the pressure sensor 73 or 74 exceeds the minimum pressure value, it can be determined that the IMU 50 is in an operating state. For example, if the pressure detected by the pressure sensor 73b or 74b, which detects the pressure for operating the boom cylinder 32, is equal to or greater than the minimum pressure value, it is determined that the boom cylinder 32 is operating, and the boom IMU 50a is in an operating state.

[0037] The front members, boom 31, arm 33, and bucket 35, are connected in series, so when the boom 31 is operated, the arm 33 and bucket 35 also move, and when the arm 33 is operated, the bucket 35 also moves. Therefore, in this embodiment, when a certain front member is determined to be in an operating state based on the detection values ​​of pressure sensors 73 and 74, the front members located further distal than the certain front member are also determined to be in an operating state. For example, when it is determined that only the arm IMU 50b is operating, the operation flag of the boom IMU 50a remains at 0, and the operation flags of the arm IMU 50b and bucket IMU 50c are set to 1.

[0038] If the operating state of the IMU 50 (i.e., the state of flag 1) continues for a predetermined time T1 or more (for example, any value within the range of "6 seconds - 2 seconds"), the flag is set to 2. Flag 2 indicates that the state is such that it is possible to determine whether or not correction of the scale factor of the angular velocity sensor of the IMU 50 is necessary. For an IMU 50 whose flag has once become 2, the flag will thereafter only transition to 3 (described below) or 0. The duration of flag 1 can be measured by integrating the cycles, and this calculation may be performed by the operating state estimation unit 61, for example.

[0039] When the flag for the IMU 50 is set to 2 and the operating speed of the IMU 50 fluctuates by a predetermined value or more, it is preferable to set the flag to 3, since it is considered difficult to determine whether or not the scale factor needs to be corrected. This is because a large fluctuation in the operating speed can result in a large calculation error in the first rotation angle θ1. Here, "when the operating speed of the IMU 50 fluctuates by a predetermined value or more" may be determined to be when the values ​​of the pressure sensors 73 and 74 change suddenly, i.e., when the change in pressure value per time exceeds a predetermined value. Alternatively, it may be determined to be the case when the change in angular velocity per time (angular acceleration) of the IMU 50 reaches a predetermined angular acceleration A1 or more. For example, the predetermined angular acceleration may be A1=40 degrees / sec. 2In detecting the angular acceleration, for example, the amount of change per time of the angular velocity sensor of the IMU 50 may be used, or the angular acceleration may be estimated from changes in the detected pressure values ​​of the pressure sensors 73 and 74.

[0040] For IMU50 whose flag has once become 3, it will only change to 0 thereafter.

[0041] Since the subsequent processing does not depend on the installation location of the IMU 50, the following description will be given using only the IMU 50a attached to the boom 31 as an example. The same calculations are also performed by the IMUs 50c and 50d mounted on the arm 33 and bucket 35, respectively.

[0042] (Step S20) After the flag is set in step S10, the process proceeds to step S20 in which the first rotation angle calculation unit 62 performs processing.

[0043] The first rotation angle calculation unit 62 (controller 60) performs an integral calculation of the angular velocity using the operation flag of the IMU 50a of the current period set by the operation state estimation unit 61, the operation flag of the IMU 50a of the previous period, and the angular velocity output from the angular velocity sensor of the IMU 50a. Note that, from the viewpoint of ensuring the accuracy of the calculation of the integral of the angular velocity, it is preferable that the operation velocity of the IMU 50 is equal to or greater than a predetermined velocity V1. For example, V1 = 5 degrees / sec can be selected as the predetermined velocity. To detect the operation velocity of the IMU 50, for example, the angular velocity sensor of the IMU 50 may be used, or the velocity may be estimated from the detected pressure values ​​of the pressure sensors 73 and 74.

[0044] If the operation flag of the IMU 50a one cycle ago is 0 and the current operation flag is also 0, the first rotation angle calculation unit 62 determines that the IMU 50a (boom 31) is not moving and sets the angular velocity integral value to 0. In other words, the first rotation angle θ1 is set to 0.

[0045] If the current operation flag of the IMU 50a is 1, the first rotation angle calculation unit 62 determines that the IMU 50a is moving, and adds the product of the angular velocity value of the IMU 50a and the calculation period to the angular velocity integral value of the previous period.

[0046] If the current operation flag of the IMU 50a is 2, the IMU 50a is moving, and when it stops, it is possible to determine whether or not the scale factor needs to be corrected. Therefore, the first rotation angle calculation unit 62 multiplies the angular velocity value of the IMU 50a by the calculation period and adds the product to the angular velocity integral value of the previous period.

[0047] If the current operation flag of the IMU 50a is 3, when the IMU 50a stops, it is not possible to determine whether or not the scale factor needs to be corrected, so the angular velocity integral value is set to 0. In other words, the first rotation angle θ1=0.

[0048] If the current operation flag of the IMU 50a is 0 (if it is determined that the IMU 50a has stopped) and the operation flag one cycle ago was 1, the IMU 50a has not been able to operate for the time required to determine whether or not the scale factor needs to be corrected, so the angular velocity integral value is set to 0. In other words, the first rotation angle θ1 is set to 0.

[0049] If the current operation flag of IMU 50a is 0 (if it is determined that IMU 50a has stopped) and the operation flag of one cycle ago was 2, the IMU has been operating for a sufficient time to determine whether or not a scale factor correction is necessary, so the first rotation angle calculation unit 62 calculates and stores the previous value of the angular velocity integral (i.e., the angular velocity integral value of one cycle ago) as the first rotation angle θ1.

[0050] (Step S30) Next, in step S30, processing is performed by the second rotation angle calculation unit 63. The second rotation angle calculation unit 63 (controller 60) uses the operation flag of the current IMU 50a set by the operation state estimation unit 61, the operation flag of the IMU 50a from one cycle ago, and the acceleration output from the acceleration sensor of the IMU 50a to calculate a second rotation angle θ2, which is the difference (amount of change) between the tilt angle (detected angle) α detected by the IMU 50a immediately before the start of operation and the tilt angle (detected angle) β detected by the IMU 50a immediately after the end of the operation.

[0051] If the operation flag of IMU 50a one cycle ago is 0 and the current operation flag is also 0 (i.e., the IMU is stopped), the tilt angle of IMU 50a (this angle may ultimately become the tilt angle α just before the start of operation (pre-operation tilt angle)) is calculated from the output of the acceleration sensor of IMU 50a.

[0052] If the operation flag of the IMU 50a one cycle ago is 0 and the current operation flag is 1 (that is, the state where the IMU 50a has started moving), the tilt angle of the IMU 50a calculated one cycle ago is stored as the pre-operation tilt angle α.

[0053] If the operation flag of the IMU 50a one cycle before is 1 or 2 and the current operation flag is also 1 or 2 (i.e., the IMU 50a is in a state of continuing to move), the previous pre-operation tilt angle α is held.

[0054] If the operation flag of IMU 50a one cycle ago is 1 and the current operation flag is 0 (i.e., if the IMU has stopped moving but has not moved enough to determine whether scale factor correction is necessary), the tilt angle of IMU 50a is calculated from the value of the acceleration sensor of IMU 50a.

[0055] If the operation flag of IMU 50a one cycle ago is 2 and the current operation flag is 0 (i.e., if the IMU has moved from a moving state to a stopped state and has moved sufficiently to determine whether scale factor correction is necessary), the tilt angle of IMU 50a is calculated from the output of the acceleration sensor of IMU 50a and set as the post-operation tilt angle β. Furthermore, the difference between this and the held pre-operation tilt angle α is calculated to calculate the second rotation angle θ2.

[0056] If the current operation flag of the IMU 50a is 3 (that is, if there is an operation that is inappropriate for determining whether or not scale factor correction is required), the tilt angle calculated one cycle before is stored as the pre-operation tilt angle α.

[0057] If the operation flag of IMU 50a one cycle ago is 3 and the current operation flag is 0 (i.e., the state has changed from a moving state to a stopped state, but includes an operation that is inappropriate for determining whether or not scale factor correction is required), the tilt angle of IMU 50a is calculated from the output of the acceleration sensor of IMU 50a.

[0058] (Step S40) Next, in step S40, processing is performed by the correction necessity determination unit 64. The correction necessity determination unit 64 (controller 60) determines whether or not correction of the scale factor of the angular velocity sensor of the IMU 50a is necessary based on the operation flag of the current IMU 50a calculated by the operation state estimation unit 61, the operation flag of the IMU 50a from one cycle ago, the first rotation angle θ1 calculated in step S20, and the second rotation angle θ2 calculated in step S30.

[0059] When the operation flag of the IMU 50a one cycle ago is 2 and the current operation flag is 0 (i.e., when the IMU 50a is stopped and operating appropriately for determining whether a scale factor is required), the first rotation angle θ1 and the second rotation angle θ2 are calculated. In this case, the correction necessity determination unit 64 (controller 60) compares the two rotation angles θ1 and θ2 to determine whether the scale factor of the angular velocity sensor of the IMU 50a needs to be corrected. For example, if the difference between the first rotation angle θ1 and the second rotation angle θ2 is equal to or greater than a predetermined value δ1, the correction necessity determination unit 64 determines that the scale factor of the angular velocity sensor of the IMU 50a needs to be corrected. On the other hand, if the difference between the two rotation angles θ1 and θ2 is less than the predetermined value δ1, the correction necessity determination unit 64 determines that the scale factor does not need to be corrected. Note that the "predetermined value δ1" may be set according to the required accuracy for control of the working device 30. For example, δ1 = 0.2% × θ2 may be used.

[0060] The above determination process is not performed unless the operation flag of the IMU 50a one cycle before is 2 and the current operation flag is 0.

[0061] If it is determined in step S40 that correction is necessary, the process proceeds to step S50. On the other hand, if it is determined in step S40 that correction is not necessary or if the above determination process has not been performed, the process ends (returns to start) and waits until the next cycle.

[0062] (Step S50) In step S50, the operator is notified via the notification device 69 that correction of the angular velocity sensor of the IMU 50a is necessary. Alternatively, or in addition to this notification, a correction value φ for the scale factor of the angle sensor of the IMU 50a may be calculated from the first rotation angle θ1 and the second rotation angle θ2, and the correction value φ may be used thereafter to correct the output of the angular velocity sensor of the IMU 50a. For example, the correction value φ is φ = θ2 / θ1, and correction can be achieved by multiplying the output of the angular velocity sensor of the IMU 50a that is subsequently output by the correction value φ. For example, by multiplying the first rotation angle θ1 obtained after calculating the correction value φ by the correction value φ, the corrected first rotation angle can be made closer to the second rotation angle θ2.

[0063] As described above, it is possible to determine whether or not correction (calibration) of the scale factor of the angular velocity sensor of the IMU 50 is necessary without interrupting work by the construction machine 100, and if correction is necessary, the correction can be completed.

[0064] The scale factor of the angular velocity sensor may be corrected within the controller 60, or the correction value φ may be notified to the IMU 50 and the correction may be performed on the IMU 50 side. Also, all or part of the processing performed by the controller 60 may be performed within the IMU 50.

[0065] Furthermore, in the above, in order to ensure the accuracy of the calculation of the angular velocity integral value by the first rotation angle calculation unit 62, the conditions for determining whether or not the scale factor needs to be corrected are that the operation of the IMU 50a (I) continues for a predetermined time T1 or more and (II) is less than a predetermined acceleration A1. However, if a certain degree of error is allowed in the angular velocity integral value, the processing of the controller 60 may be configured to determine whether or not the correction is needed even if at least one of these conditions (I) and (II) is not met.

[0066] Furthermore, instead of the above conditions (I) and (II), the controller 60 may be configured to calculate the distance between the tip of the working implement 30 (i.e., the toe of the bucket 35 if the attachment of the working implement 30 is the bucket) and the target excavation surface, and determine whether or not the scale factor needs to be corrected if the distance remains less than a predetermined value D1 for a predetermined time T2 or longer. When this condition is met, it is highly likely that the construction machine 100 is performing finishing work, moving the bucket toe back and forth along the target excavation surface to form a flat surface. In this case, it is highly likely that the speed of the IMU 50 is greater than or equal to a predetermined value V1 and the acceleration is less than a predetermined acceleration A1. In other words, if this condition is met, it is deemed that the above conditions (I) and (II) are met, and therefore it is possible to determine whether or not correction is needed. The predetermined value D1 can be selected from a range of, for example, 20 cm to 5 cm, and the predetermined time T2 can be the same as T1, or can be selected from a range of, for example, 6 seconds to 2 seconds. Furthermore, the position of the tip of the working device 30 can be calculated from the attitude and dimensions of each of the front members 31, 33, 35 and the upper rotating body 20, and the orientation and position of the upper rotating body 20. It goes without saying that the attitude of each of the front members 31, 33, 35 and the upper rotating body 20 can be calculated from the output of the IMU 50, and the orientation and position of the upper rotating body 20 can be obtained by installing multiple antennas and receivers for satellite positioning on the upper rotating body 20.

[0067] Next, changes in the operation flag, angular velocity integral value, and tilt angle that appear when the flow of FIG. 3 is executed will be described with a specific example in FIG.

[0068] 4 show, from top to bottom, the operation flag of IMU 50a set by operation state estimation unit 61, the angular velocity integral value calculated by first rotation angle calculation unit 62, and the tilt angle calculated by second rotation angle calculation unit 63, with the horizontal axis of each graph representing time t (seconds). For the sake of explanation, all angular velocities when it is determined that IMU 50a is operating normally are set to 2 [deg / sec], and the calculation cycle of the flowchart in FIG. 3 is set to 1 second.

[0069] First, when the flow starts with the operation flag at 0 (t = 0 seconds), the IMU 50a is not operating until t = 5 seconds, so the angular velocity is not integrated and remains 0. Meanwhile, the tilt angle is constantly calculated from the output of the acceleration sensor and indicates 20 degrees.

[0070] When the operation flag changes to 1 (operating state) (t = 5 seconds), angular velocity integration begins, and the angular velocity integral value is added (integrated) over time. Regarding the tilt angle, the value one cycle before the start of operation (t = 4 seconds) is held as the pre-operation tilt angle α (α = 20 degrees).

[0071] At 15 seconds, the operation flag changes from 1 to 2, but the above calculation continues as from 5 seconds to 14 seconds.

[0072] At 20 seconds, the operation flag changes from 2 to 0, and the previous value of the angular velocity integral (30 degrees at t = 19 seconds) is calculated as the first rotation angle θ1. The tilt angle calculated from the current (t = 20 seconds) acceleration is set as the post-operation tilt angle β (β = 55 degrees), and the second rotation angle θ2 (θ2 = β - α = 35 degrees) is calculated from the difference between this and the pre-operation tilt angle α (value at t = 4 seconds). This is the flow when it is possible to correctly determine whether correction of the angular velocity scale factor is necessary. In this case, the difference between the two rotation angles θ1 and θ2 is 5 degrees, and the need for correction is determined based on this value. For example, when the predetermined value δ1 of the difference is δ1 = 0.2% × θ2, δ1 = 0.2% × 35 degrees = 0.07 degrees < θ2 - θ1 = 5 degrees, so it is determined that "correction is necessary."

[0073] Next, we will explain the flow when the IMU 50a comes to a standstill before the operation flag changes from 1 to 2, such as from 30 seconds to 35 seconds (in other words, when the flag changes from 1 to 0). When the operation flag becomes 1 at t = 30 seconds, angular velocity integration begins, but the operation flag becomes 0 at t = 35 seconds, so the integrated value of angular velocity becomes 0. Regarding the tilt angle, in the range of 30 seconds or more but less than 35 seconds, the tilt angle at 29 seconds (55 degrees) is held as the pre-operation tilt angle α, but from 35 seconds onwards, a new tilt angle (65 degrees) is obtained from the acceleration sensor.

[0074] Next, we will explain what happens when the action flag changes from 1 to 3, such as from 40 seconds to 50 seconds (i.e., when an action that is not suitable for judgment occurs). In this case, the action flag becomes 3 at t=45 seconds, so the integral value of the angular velocity becomes 0, and the tilt angle becomes the value at t=44 seconds (65 degrees).

[0075] (effect) (1) In the above embodiment, in a construction machine 100 equipped with a work implement 30 having a plurality of connected front members 31, 33, 35, an angular velocity sensor 50av and an acceleration sensor 50aa attached to a front member (for example, the boom 31; here, the respective symbols are assigned assuming the boom 31), and a controller 60 that calculates the posture of the front member 31 using the outputs of the angular velocity sensor 50av and the acceleration sensor 50aa, the controller 60 calculates the integral value of the angular velocity detected by the angular velocity sensor 50av during movement M of the front member 31 as a first rotation angle θ1, calculates the difference between the angle detected by the acceleration sensor 50aa before and after the movement M of the front member 31 as a second rotation angle θ2, and when the deviation between the first rotation angle θ1 and the second rotation angle θ2 is equal to or greater than a predetermined value δ1, outputs to an alarm device 69 that correction of the scale factor of the angular velocity sensor 50av is necessary.

[0076] With the construction machine 100 configured in this manner, the first rotation angle θ1 is calculated from the angular velocity detected by the angular velocity sensor 50av during movement M, and the second rotation angle θ2 is calculated from the angle detected by the acceleration sensor 50aa before and after movement M. This makes it possible to determine whether the difference between the first and second rotation angles is equal to or greater than a predetermined value δ1 without stopping the construction machine. That is, with this embodiment, it is possible to determine whether calibration (correction) of the scale factor of the angular velocity sensor is necessary without interrupting work. Furthermore, because the need for correction is determined during work, a decrease in work efficiency can be prevented, and the timing when correction is necessary can be accurately determined.

[0077] (2) In (1) above, it is preferable that the first rotation angle θ1 and the second rotation angle θ2 are calculated when the movement M of the front member 31 continues for a predetermined time T1 or more. By calculating the first rotation angle θ1 and the second rotation angle θ2 when the movement M continues for a predetermined time T1 or more in this way, the amount of change in angle of the IMU 50 (angular velocity sensor and acceleration sensor) before and after the movement M is ensured, and therefore it is possible to suppress an error between the integrated value obtained from the angular velocity sensor and the amount of change in the tilt angle obtained from the acceleration sensor.

[0078] (3) In any one of (1)-(2) above, it is preferable that the first rotation angle θ1 and the second rotation angle θ2 are calculated when the movement M of the front member 31 is equal to or greater than a predetermined speed V1. By calculating the first rotation angle θ1 and the second rotation angle θ2 when the movement M is equal to or greater than the speed V1, it is possible to prevent an error from occurring in the integral value of the angular velocity obtained by the angular velocity sensor of the IMU 50, i.e., the first rotation angle θ1.

[0079] (4) In any one of the above (1) to (3), it is preferable that the first rotation angle θ1 and the second rotation angle θ2 are calculated when the movement M of the front member 31 is less than a predetermined angular acceleration A1. In this way, when the movement M is less than the angular acceleration A1, velocity fluctuations are suppressed, and it is possible to suppress the occurrence of errors in the integral value of the angular velocity measured by the angular velocity sensor of the IMU 50, i.e., the first rotation angle θ1.

[0080] (5) In any one of (1)-(4) above, it is preferable that the controller 60 determines whether the deviation between the first rotation angle θ1 and the second rotation angle θ2 is equal to or greater than a predetermined value δ1 when the state in which the distance between the tip of the working device 30 and the excavation target surface is less than a predetermined value D1 continues for a predetermined time T2 or more. In this case, the motion M can be considered to be moving at a predetermined speed V1 or more and less than a predetermined acceleration A1, thereby preventing an error from occurring in the first rotation angle θ1.

[0081] (6) In any one of the above (1) to (5), the notification device 69 is preferably at least one of a monitor, a speaker, and a warning light.

[0082] (7) In any one of (1) to (6) above, when it is determined that the scale factor of the angular velocity sensor 50av needs to be corrected, the controller 60 preferably corrects the output of the angular velocity sensor so that the first rotation angle θ1 approaches the second rotation angle θ2. This allows the scale factor of the angular velocity sensor to be corrected without interrupting work by the construction machine.

[0083] (8) In any one of the above (1) to (7), it is preferable to further include a sensor (for example, pressure sensor 73, 74) that detects the amount of operation of the operating device on the front members 31, 33, 35, the pressure of the actuators 32, 34, 36 that drive the front members 31, 33, 35, or the operation signal to the actuators 32, 34, 36, and the controller 60 determines the start and end of the movement M of the front member 31 based on the detected value of the sensor. Using such a sensor makes it easy to determine the start and end of the movement M.

[0084] (9) In (8) above, it is preferable that the controller 60 calculates the speed and acceleration of the movement M of the front member 31 based on the detection values ​​of the sensors, and determines whether the deviation between the first rotation angle θ1 and the second rotation angle θ2 is equal to or greater than a predetermined value δ1 when the speed of the movement of the front member 31 is equal to or greater than a predetermined speed V1 and the angular acceleration of the movement of the front member 31 is less than a predetermined angular acceleration A1. This makes it possible to prevent an error from occurring in the first rotation angle θ1.

[0085] <Second embodiment> 5 is a schematic diagram of a correction necessity determination system according to a second embodiment. This embodiment is characterized in that the correction necessity determination system includes a server (control device) 60A communicably connected to a controller 60 via a network 200, and the server 60A receives the outputs of the IMU 50 and sensors 73, 74 mounted on the construction machine 100 and determines whether correction of the scale factor of the angular velocity sensor of the IMU 50 is necessary. In the following description, the same parts as those in the previous figures are designated by the same reference numerals, and descriptions of these parts may be omitted.

[0086] The correction necessity determination system of Figure 5 includes an IMU 50 (angular velocity sensor and acceleration sensor) attached to the front members 31, 33, 35 of the work implement 30 mounted on the construction machine 100, a server (control device) 60A that receives the output of the angular velocity sensor and acceleration sensor of the IMU 50, and an alarm device 69 that notifies whether correction of the scale factor of the angular velocity sensor of the IMU 50 is necessary.

[0087] The server 60A includes a communication device 82 for communicating with the controller 60 via the network 200. Similar to the controller 60 shown in Fig. 2, the server 60A also includes a motion state estimation unit 61, a first rotation angle calculation unit 62, a second rotation angle calculation unit 63, and a correction necessity determination unit 64. The motion state estimation unit 61 receives the outputs of the pressure sensors 73 and 74 transmitted via the network 200, the first rotation angle calculation unit 62 receives the output of the angular velocity sensor of the IMU 50 transmitted via the network 200, and the second rotation angle calculation unit 63 receives the output of the acceleration sensor of the IMU 50 transmitted via the network 200.

[0088] The controller 60 includes a communication device 81 for communicating with the server 60A via the network 200.

[0089] Similar to the controller 60 of the first embodiment, the server 60A calculates the integral value of the angular velocity detected by the angular velocity sensor of the IMU 50a during operation of the front member (e.g., the boom 31; here, each symbol is assigned assuming the boom 31) as the first rotation angle θ1, calculates the difference in the angle detected by the acceleration sensor of the IMU 50a before and after the operation of the front member 31 as the second rotation angle θ2, and outputs to the alarm device 69 that correction of the scale factor of the angular velocity sensor of the IMU 50a is necessary when the deviation between the first rotation angle θ1 and the second rotation angle θ2 is greater than or equal to a predetermined value δ1.

[0090] Even with such a system configuration, it is possible to determine whether the difference between the first and second rotation angles θ1, θ2 is equal to or greater than the predetermined value δ1 without stopping the construction machine 100. In other words, it is possible to determine whether calibration (correction) of the scale factor of the angular velocity sensor is necessary without interrupting work. Furthermore, because the necessity of correction is determined during work, it is possible to prevent a decrease in work efficiency and, further, to accurately know the timing when correction is necessary.

[0091] Note that a system may be configured in which some of the processing performed by the server 60A is executed by the controller 60 and the output results are transmitted to the server 60A. For example, a system may be configured in which the flag setting processing related to the motion state estimation unit 61 is executed by the controller 60, the flags set for each IMU 50 are transmitted to the server 60A, and the server 60A determines whether or not the scale factor needs to be corrected. Furthermore, the notification device 69, which outputs the determination result on whether or not correction is required, may be connected to the controller 60 or the server 60A.

[0092] The present invention is not limited to the above-described embodiments, and includes various modifications within the scope of the gist of the present invention. For example, the present invention is not limited to those having all of the configurations described in the above-described embodiments, and includes those in which some of the configurations are omitted. Furthermore, some of the configurations according to one embodiment can be added to or replaced with configurations according to other embodiments.

[0093] Furthermore, the components related to the controller 60 and server 60A, as well as the functions and execution processes of the components, may be partially or entirely implemented by hardware (for example, by designing logic for executing the functions as an integrated circuit). The components related to the controller 60 and server 60A may also be implemented as a program (software) that is read and executed by an arithmetic processing device (for example, a CPU) to implement the functions of the controller 60 and server 60A. Information related to the program can be stored in, for example, a semiconductor memory (flash memory, SSD, etc.), a magnetic storage device (hard disk drive, etc.), or a recording medium (magnetic disk, optical disk, etc.).

[0094] In addition, in the above description of each embodiment, the control lines and information lines are those that are considered necessary for the description of the embodiment, but they do not necessarily represent all the control lines and information lines related to the product. In reality, it can be considered that almost all components are interconnected. [Explanation of symbols]

[0095] 10... lower traveling body, 20... upper rotating body, 25... cab (operator's compartment), 30... working device, 31... boom (front member), 32... boom cylinder (actuator), 33... arm (front member), 34... arm cylinder (actuator), 35... bucket (front member), 36... bucket cylinder (actuator), 50... IMU, 60... controller, 60A... server (control device), 61... operating state estimation unit, 62... first rotation angle calculation unit, 63 ...second rotation angle calculation unit, 64...correction necessity determination unit, 69...alarm device, 70...on-vehicle network (e.g., CAN), 73...pressure sensor, 74...pressure sensor, 81...communication device, 82...communication device, 100...hydraulic excavator, 200...network, A1...predetermined acceleration, D1...predetermined distance, T1...predetermined time, T2...predetermined time, V1...predetermined speed, α...tilt angle before operation, β...tilt angle after operation, δ1...predetermined value (deviation), θ1...first rotation angle, θ2...second rotation angle, φ...correction value

Claims

1. A construction machine comprising: a working implement having a plurality of connected front members; an angular velocity sensor and an acceleration sensor attached to the front members; and a controller that calculates the attitude of the front members using outputs of the angular velocity sensor and the acceleration sensor, the controller calculates an integral value of the angular velocity detected by the angular velocity sensor during movement of the front member as a first rotation angle, calculates a difference between the angles detected by the acceleration sensor before and after the movement of the front member as a second rotation angle, and when a deviation between the first rotation angle and the second rotation angle is equal to or greater than a predetermined value, outputs to an alarm device a notification that a correction of the scale factor of the angular velocity sensor is necessary.

2. The construction machine of claim 1, A construction machine characterized in that the first rotation angle and the second rotation angle are calculated when the movement of the front member continues for a predetermined time or more.

3. The construction machine of claim 1, A construction machine characterized in that the first rotation angle and the second rotation angle are calculated when the speed of the movement of the front member is equal to or greater than a predetermined speed.

4. The construction machine of claim 1, A construction machine characterized in that the first rotation angle and the second rotation angle are calculated when the angular acceleration of the movement of the front member is less than a predetermined angular acceleration.

5. The construction machine of claim 1, The controller determines whether the deviation between the first rotation angle and the second rotation angle is equal to or greater than the predetermined value when the distance between the tip of the working device and the excavation target surface remains less than the predetermined value for a predetermined period of time or more.

6. The construction machine of claim 1, The construction machine is characterized in that the notification device is at least one of a monitor, a speaker, and a warning light.

7. The construction machine of claim 1, When it is determined that correction of the scale factor of the angular velocity sensor is necessary, the controller corrects the output of the angular velocity sensor so that the first rotation angle approaches the second rotation angle.

8. The construction machine of claim 1, a sensor for detecting any one of an operation amount of an operating device for the front member, a pressure of an actuator that drives the front member, and an operation signal for the actuator; The construction machine is characterized in that the controller determines the start and end of movement of the front member based on the detection values ​​of the sensors.

9. The construction machine according to claim 8, The controller calculates the speed and angular acceleration of the movement of the front member based on the detection values ​​of the sensors, and when the speed of the movement of the front member is equal to or greater than a predetermined speed and the angular acceleration of the movement of the front member is less than the predetermined angular acceleration, determines whether or not the correction is necessary based on the deviation between the first rotation angle and the second rotation angle.

10. A correction necessity determination system including an angular velocity sensor and an acceleration sensor attached to a front member of a work implement mounted on a construction machine, a control device that receives outputs of the angular velocity sensor and the acceleration sensor, and a notification device that notifies whether a scale factor of the angular velocity sensor needs to be corrected, The control device calculates an integral value of the angular velocity detected by the angular velocity sensor during movement of the front member as a first rotation angle, calculates a difference between the angles detected by the acceleration sensor before and after the movement of the front member as a second rotation angle, and when a deviation between the first rotation angle and the second rotation angle is equal to or greater than a predetermined value, outputs to an alarm device that correction of the scale factor of the angular velocity sensor is necessary.

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