Work machine and remote control device

Abstract

Provided is a work machine comprising: an object detection device that detects surrounding objects; a travel sensor that detects the operation of a travel body; a displacement sensor that detects the displacement of the travel body; a drive device that drives the travel body, a swing body, and a front work machine; and a control device that controls the drive device on the basis of detection results of the object detection device, the travel sensor, and the displacement sensor. The control device: calculates, on the basis of a detection signal of the object detection device, the position of an object serving as a reference for the control of the travel body, the swing body, and the front work machine; controls the swing body and the front work machine on the basis of the position of the object; and recalculates, on the basis of detection signals of the travel sensor and the displacement sensor, the position of the object when the travel body is displaced while the operation of the travel body is stopped. Thus, deviations in the recognition of the actual positional relationship with a transport vehicle are suppressed, and soil is accurately loaded on the transport vehicle while moving a bucket in a trajectory resulting in less loss.

Description

Work machine and remote control device

[0001] The present invention relates to a work machine such as a hydraulic excavator and a remote control device.

[0002] BACKGROUND ART In recent years, automation and semi-automation of work has progressed in work machines such as hydraulic excavators and bulldozers, for example, with a control system intervening in the control of the work machine in response to specific operations by an operator.

[0003] As an example of automatic control of a hydraulic excavator, a technology has been disclosed in which a bucket is moved toward a target position, the destination area is recognized by a sensor, and the bucket position is corrected if the bucket position deviates from the actual target position recognized by the sensor (Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2022-77328

[0005] Hydraulic excavators are sometimes used as loading machines that load excavated soil and other materials onto dump trucks, which are transport vehicles. Automating or semi-automating the loading of soil and sand onto transport vehicles requires a control system with high accuracy to identify the relative position of the transport vehicle with respect to the hydraulic excavator. However, when excavating the ground, the hydraulic excavator's tracks may slip on the ground due to a reaction force, causing the vehicle body to be pulled toward the excavation position. In this case, the hydraulic excavator moves relative to the transport vehicle, but because this movement is not instructed by the operator or the control system, the actual relative positions of the hydraulic excavator and the transport vehicle as perceived by the control system may differ. When automatic loading control is executed in this state, the position at which the hydraulic excavator loads the soil may shift, resulting in soil spilling from the transport vehicle and reduced productivity.

[0006] In contrast, in the case of the technology described in Patent Document 1, after the bucket is moved toward the target position, the actual target position is recognized by a sensor and the bucket position is corrected as necessary. Therefore, even if the relative positions of the hydraulic excavator and the transport vehicle are shifted, the bucket position is corrected before releasing the soil, and the shift in the loading position can be corrected.

[0007] However, in the technology described in this document, the bucket position is checked and corrected after it has been moved toward the target position, so the bucket does not necessarily move to the loading position along the shortest trajectory, which can result in lost time in bucket movement, and productivity decreases if this operation is repeated.

[0008] An object of the present invention is to provide a work machine and a remote control device that can suppress discrepancies in the recognition of the actual positional relationship with a transport vehicle, move a bucket on a trajectory with minimal loss, and accurately load earth and sand onto a transport vehicle.

[0009] In order to achieve the above object, the present invention provides a work machine including a running body, a rotating body rotatably mounted on the upper part of the running body, and a front work implement attached to the rotating body, the work machine comprising: an object detection device that detects objects around the work machine; a running sensor that detects the movement of the running body; a displacement sensor that detects the displacement of the running body; a drive unit that drives the running body, the rotating body, and the front work implement; and a control device that controls the drive unit based on the detection results of the object detection device, the running sensor, and the displacement sensor, the control device calculating the position of an object that serves as a reference for control of the running body, the rotating body, and the front work implement based on the detection signal from the object detection device, controlling the rotating body and the front work implement based on the position of the object, and recalculating the position of the object based on the detection signals from the running sensor and the displacement sensor if the running body is displaced while the operation of the running body is stopped.

[0010] According to the present invention, it is possible to suppress discrepancies in the recognition of the actual positional relationship with the transport vehicle, and to load earth and sand onto the transport vehicle with high accuracy while moving the bucket on a trajectory with minimal loss.

[0011] A side view of a hydraulic excavator, which is an example of a work machine according to a first embodiment of the present invention. A diagram showing an example of an operating site of the work machine of Figure 1. A functional block diagram of a control device provided on the work machine of Figure 1. A flowchart showing an example of a processing procedure performed by a control device provided on a work machine according to a first embodiment of the present invention. A diagram showing a state in which an unintended movement of the hydraulic excavator occurs. A flowchart showing an example of a processing procedure performed by a control device provided on a work machine according to a second embodiment of the present invention. A flowchart showing an example of a processing procedure performed by a control device provided on a work machine according to a third embodiment of the present invention.

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] In this embodiment, an automatically operable large hydraulic excavator will be described as an example of a work machine that is an automatic loading machine. However, the present invention is not limited to large hydraulic excavators, and can also be applied to work machines that are the subject of automatic operation in cooperation with other vehicles, such as small hydraulic excavators and large crane trucks. Furthermore, the present invention is not limited to automatic operation, and can also be applied to operation assist control that semi-automatically assists operator operation, and operation assist control for remote operation.

[0014] 1 is a side view of a hydraulic excavator 1, which is an example of a work machine according to a first embodiment of the present invention. The hydraulic excavator 1 includes a traveling body 5, a revolving body 3, a front work implement 4, drive units 7a and 7b, an object detection device 8, and a control device 6.

[0015] -Traveling body- The traveling body 5 has a travel motor, and travels when the travel motor is driven by the drive unit 7b, moving the hydraulic excavator 1 forward and backward and left and right, and turning (pivoting) on ​​the spot. The traveling body 5 is of a crawler type, but can also be of a wheel type.

[0016] The rotating body 3 is rotatably mounted on the upper part of the running body 5, and is rotated left and right relative to the running body 5 by driving a rotary motor via a drive unit 7a. The rotating body 3 also includes a cab 2 for an operator to operate the hydraulic excavator 1, drive units 7a and 7b, a control unit 6, etc.

[0017] -Front Work Unit- The front work unit 4 is attached to the revolving unit 3 and is configured to include, for example, a boom 4a, an arm 4b, and a bucket 4c. The boom 4a is driven by a boom cylinder 4d, the arm 4b by an arm cylinder 4e, and the bucket 4c by a bucket cylinder 4f. The boom cylinder 4d, arm cylinder 4e, and bucket cylinder 4f are driven by a drive unit 7a.

[0018] - Drive unit - The drive unit 7 is configured to include a drive unit 7a that drives the front working mechanism 4 and the revolving unit 3, and a drive unit 7b that drives the traveling unit 5. The drive unit 7 is made up of various hydraulic devices such as a hydraulic pump and a control valve. An engine (internal combustion engine) can be used as the prime mover that drives the hydraulic pump, and in some cases an electric motor can be used instead of the engine.

[0019] -Object Detection Device- The object detection device 8 is a sensor that detects objects (including the terrain and the ground surface) around the hydraulic excavator 1, and is connected to the control device 6 via a signal line. In this embodiment, the object detection device 8 detects the relative position of objects around the hydraulic excavator 1 with respect to the object detection device 8 and the distance from the object detection device 8 to the objects, and outputs the detection results. The object detection device 8 acquires data corresponding to the distance from the object detection device 8 to the target objects around the hydraulic excavator 1, and this data is input to the control device 6 as an output signal from the object detection device 8. The object detection device 8 may be, for example, a stereo camera or a LiDAR (Light Detection and Ranging) device. It is also possible to provide multiple object detection devices 8 or combine multiple types of devices using different methods to expand the measurement area and improve measurement accuracy.

[0020] 1 is equipped with a motion detection sensor 10a (FIG. 3) provided in the drive unit 7a, a travel sensor 10b (FIG. 3) provided in the drive unit 7a, and a displacement sensor (described later) that detects the displacement of the travelling body 5. The motion detection sensor 10a includes a sensor that detects the motion of the front working implement 4 and a sensor that detects the motion of the revolving body 3. Each of these sensors is connected to the control device 6 via a signal line.

[0021] Sensors for Detecting Operation of the Front Work Implement As sensors for detecting the operation of the front work implement 4, for example, pressure sensors that detect the pressure in the bottom-side oil chambers and rod-side oil chambers of the boom cylinder 4d, arm cylinder 4e, and bucket cylinder 4f can be used. Alternatively, angle sensors that detect the angles of the boom 4a, arm 4b, and bucket 4c can also be used as sensors for detecting the operation of the front work implement 4. An IMU (Inertial Measurement Unit) that detects the acceleration, angular velocity, angle, etc. of the boom 4a, arm 4b, and bucket 4c, or a sensor that detects operation signals related to the boom 4a, arm 4b, and bucket 4c can also be used as sensors for detecting the operation of the front work implement 4. Furthermore, when an electric motor or the like is used for the drive device 7a, an ammeter or a voltmeter can also be used as a sensor for detecting the operation of the front work implement 4.

[0022] Sensor for detecting the movement of the revolving body As a sensor for detecting the movement of the revolving body 3, for example, a pressure sensor for detecting the port pressure of the revolving motor can be used. In addition, an angle sensor for detecting the angle of the revolving body 3 relative to the running body 5 can also be used as a sensor for detecting the movement of the revolving body 3. An IMU for detecting the acceleration, angular velocity, angle, etc. of the revolving body 3, or a sensor for detecting an operation signal related to the revolving body 3 can also be used as a sensor for detecting the movement of the revolving body 3. Furthermore, when an electric motor or the like is used for the drive device 7a, an ammeter or a voltmeter can also be used as a sensor for detecting the movement of the revolving body 3.

[0023] Sensor for detecting the movement of the running body The running sensor 10b is a sensor that detects the movement of the running body 5, and for example, a pressure sensor that detects the port pressure of each of the left and right running motors can be used. In addition, an IMU that detects the acceleration, angular velocity, angle, etc. of the running body 5, or a sensor that detects an operation signal related to the running body 5 can also be used as a sensor that detects the movement of the running body 5. Furthermore, when an electric motor or the like is used for the drive device 7b, an ammeter or a voltmeter can also be used as a sensor that detects the movement of the running body 5.

[0024] - Sensor for detecting displacement of the running body In addition, as a displacement sensor for detecting the displacement of the running body 5, a positioning device (position and orientation measuring instrument) 9 for acquiring the position of the rotating body 3 and the object detection device 8 mentioned above are installed, and at least one of the positioning device 9 and the object detection device 8 can be used as a displacement sensor to detect basic data for calculating the amount of change in the position and orientation of the running body 5.

[0025] The positioning device 9 is a sensor that can acquire the position and azimuth angle relative to any point on the site of the hydraulic excavator 1. The positioning device 9 can use, for example, a Global Navigation Satellite System (GNSS) or a GNSS compass that calculates the azimuth from the difference in the positions of GNSS mobile stations installed at intervals on the rotating unit 3. The position and azimuth of the rotating unit 3 can be converted into the position and azimuth of the running unit 5 based on data such as the angle of the rotating unit 3 relative to the running unit 5, dimensional data of the rotating unit 3 and the running unit 5, and the positions of the GNSS mobile stations relative to the rotating unit 3.

[0026] <Control Device> The control device 6 is an on-board computer that controls the drive device 7 based on detection results from the object detection device 8, the travel sensor 10b, the positioning device 9, the motion detection sensor 10a, etc., and controls the traveling body 5, the revolving unit 3, and the front work unit 4, and is, for example, a programmable electronic device equipped with a CPU and memory. As described above, the control device 6 is connected to sensors such as the object detection device 8, the positioning device 9, the motion detection sensor 10a, and the travel sensor 10b via signal lines, and is also connected via signal lines to the operation device of the cab 2 and each of the controlled devices included in the drive devices 7a and 7b. For example, the control device 6 commands the drive devices 7a and 7b in response to operation signals input from an operation device (not shown) in response to operation by an operator in the cab 2, and drives the front work unit 4, the revolving unit 3, and the traveling body 5. In addition, the control device 6 has the function of generating command signals for automatically or semi-automatically controlling the front work implement 4, the rotating body 3, and the running body 5 according to an automatic driving program or semi-automatic driving program without the operation of an operator, and outputting the signals to the drive devices 7a, 7b.

[0027] - Overview of processing by the control device - Figure 2 is a diagram showing an example of an operating site of the hydraulic excavator 1. In the example shown in the figure, the hydraulic excavator 1 is performing an excavation and loading operation by excavating the ground, scooping earth and sand into a bucket 4c, and loading the earth and sand into a tray of a dump truck 11 (transport vehicle) by combined operation of the front working implement 4 and the swing device 3.

[0028] To give a brief overview of the main functions of the control device 6, first, the control device 6 calculates the position of an object that serves as a reference for controlling the running body 5, the revolving body 3, and the front work implement 4 based on the detection signal from the object detection device 8, controls the revolving body 3 and the front work implement 4 based on the position of the object, and recalculates the position of the object based on the detection signals from the travel sensor 10b and the displacement sensor (positioning device 9 or object detection device 8) if the running body 5 is displaced while its operation is stopped. Specifically, the control device 6 calculates the position of the object (for example, a specific area 12 on the ground to be leveled or a tray area 14a of a dump truck 11 into which earth and sand are loaded) in a three-dimensional reference coordinate system 13 whose positional relationship with the running body 5 is invariable based on the detection signal from the object detection device 8, and stores the calculated position of the object in memory. The control device 6 calculates the attitude and trajectory of the bucket 4c based on the position of the held object, and executes automatic or semi-automatic assist control of the rotating unit 3 and the front work implement 4 so that the bucket 4c moves along the calculated trajectory at the calculated attitude. While repeating this excavation and loading operation, the control device 6 determines whether the running unit 5 is stopped based on the detection signal from the travel sensor 10b, and determines whether the running unit 5 has displaced by more than a preset threshold based on the detection signal from the displacement sensor (positioning device 9 or object detection device 8). At this time, the amount of displacement of the running unit 5 is calculated by the control device 6 based on the detection signal from at least one of the positioning device 9 and the object detection device 8. In other words, the control device 6 determines whether the running unit 5 is moving or turning even though the operator or the control device 6 has not instructed the running unit 5 to move.

[0029] When the running unit 5 starts to move, or when the running unit 5 is displaced by a predetermined threshold or more while the running unit 5 is continuously stopped, the control device 6 recalculates the position of the object, deletes the currently held data on the position of the object, and updates the position of the object with the recalculated data. Thereafter, the control device 6 controls the revolving unit 3 and the front working implement 4 based on the updated position of the object in the same way as before the update.

[0030] Conversely, when the traveling unit 5 is stopped and the displacement of the traveling unit 5 during that time is less than the threshold value, the control unit 6 determines that the currently held position of the object is still valid and continues to hold the object position currently held in memory as valid data. In this case, the control unit 6 does not recalculate the object position, but controls the revolving unit 3 and the front working implement 4 based on the continuously held object position.

[0031] -Functional Blocks of the Control Device- Figure 3 is a functional block diagram of the control device 6 provided in the work machine of Figure 1. Control of the front work implement 4 and the like and processing of updating objects are realized by the functions illustrated in the functional block diagram of Figure 3.

[0032] 3, the control device 6 includes a control target value acquisition unit 6a, a control target value storage unit 6b, a control output unit 6c, a relative information change detection unit 6d, and a control target value update instruction unit 6e. The control target value acquisition unit 6a, the control target value storage unit 6b, the control output unit 6c, the relative information change detection unit 6d, and the control target value update instruction unit 6e are, for example, functions of the control device 6, and may be realized virtually by software or by hardware such as an electronic circuit.

[0033] -Control Target Value Acquisition Unit- The control target value acquisition unit 6a receives distance data (output signal of the object detection device 8) from the object detection device 8 and calculates the relative distance of the object from the hydraulic excavator 1 based on the distance data. The object is, for example, a dump truck 11 (FIG. 1) onto which the hydraulic excavator 1 loads earth and sand, or a specific area 12 (FIG. 1) of the ground that the hydraulic excavator 1 levels. For example, when the dump truck 11 is the object, the control target value acquisition unit 6a identifies the dump truck 11 based on distance data around the hydraulic excavator 1 and calculates the relative distance from the hydraulic excavator 1 to the tray of the dump truck 11. The relative distance is expressed, for example, as a three-dimensional vector 14b indicating the position on the reference coordinate system 13 (FIG. 2) of a center point 14c of a tray area 14a of the dump truck 11, which is the target position for discharging earth and sand. The control target value acquisition unit 6a transmits the calculated data of the relative distance to the object to the control target value holding unit 6b as data on the position of the object.

[0034] -Control Target Value Storage Unit- The control target value storage unit 6b has a memory, and when it receives relative distance data to an object from the control target value acquisition unit 6a, it stores the relative distance data in the memory. When it receives relative distance data from the control target value acquisition unit 6a, it discards the currently stored relative distance data, stores the newly received relative distance data from the control target value acquisition unit 6a in the memory, and updates the relative distance data. Furthermore, when it receives an update instruction from the control target value update instruction unit 6e, as described below, the control target value storage unit 6b sends an instruction to the control target value acquisition unit 6a to recalculate and output relative distance data, and replaces the currently stored relative distance data with the newly input relative distance data from the control target value acquisition unit 6a, updating it. The control target value storage unit 6b outputs the stored relative distance data to the control output unit 6c.

[0035] -Control Output Unit- The control output unit 6c calculates control signals for drive control of the revolving unit 3, the front work unit 4, and the traveling unit 5, and outputs control signals to the drive units 7 (drive units 7a, 7b). As an example of drive control, when the object is a dump truck 11, the control output unit 6c calculates the attitude and shortest trajectory, etc. of the bucket 4c required for loading into the dump truck 11 based on the relative distance data received from the control target value holding unit 6b, and calculates control signals for the front work unit 4 and the revolving unit 3 so that the bucket 4c moves at the calculated attitude and trajectory, and outputs these to the drive unit 7a. Also, when the object is an area 12 on the ground shown in Fig. 2, the control output unit 6c calculates the attitude and trajectory, etc. of the front work unit 4 for leveling the ground, and calculates a control signal for the front work unit 4 so that the bucket 4c moves at the calculated attitude and trajectory, and outputs this to the drive unit 7a.

[0036] - Relative Information Change Detection Unit - The relative information change detection unit 6d detects unintended movement (change in the position of the traveling body 5) or turning (change in the orientation of the traveling body 5) of the hydraulic excavator 1 based on the output signal of the positioning device 9 or the object detection device 8. Unintended movement or turning refers to, for example, movement or turning of the traveling body 5 occurring even though the control output unit 6c has not commanded the drive unit 7b to drive the traveling body 5. When the relative information change detection unit 6d detects movement or turning of the traveling body 5 as described below while detecting that the traveling body 5 is stationary based on the output signal of the travel sensor 10b (for example, in a state where no drive command is output from the control output unit 6c to the traveling body 5 and the travel motor is stopped), the relative information change detection unit 6d outputs the amount of movement or the amount of turning as a displacement to the control target value update instruction unit 6e.

[0037] For example, based on the output of the positioning device 9, the relative information change detection unit 6d can calculate the amount of movement and turning angle of the running body 5 based on the amount of movement and rotation of the reference coordinate system 13 of the hydraulic excavator 1 in the site coordinate system 15 (a coordinate system based on the ground and including the global coordinate system), which is the coordinate system of the operating site of the hydraulic excavator 1.

[0038] Furthermore, the relative information change detection unit 6d may be configured to calculate the amount of movement and the amount of turning of the vehicle 5 based on changes in the value of the vector 14b calculated based on the output of the object detection device 8. Compared to processing three-dimensional images of an object using the object detection device 8, the displacement determination process using the object detection device 8 has a smaller calculation load and can be executed reasonably frequently. For example, by using SLAM (Simultaneously Localization and Mapping) technology, it is possible to identify the position and orientation of the vehicle 5 while identifying the position of the dump truck 11 based on relative distance data from the object detection device 8.

[0039] -Control target value update instruction unit- When the control target value update instruction unit 6e receives the amount of displacement from the relative information change detection unit 6d, it determines whether or not the relative distance data held by the control target value holding unit 6b needs to be updated based on the received amount of displacement, and if it determines that an update is necessary, it outputs an update instruction to the control target value holding unit 6b. For example, if the condition of the following formula is satisfied, the control target value update instruction unit 6e determines that the relative distance data held in the control target value holding unit 6b needs to be updated: Amount of displacement≧Threshold value (Formula 1)

[0040] The threshold value used for determining movement can be, for example, a value at which the bucket 4c of the front work implement 4 deviates from the area of ​​the target object (for example, the tray area 14a), and is set in advance and stored in memory. The smaller the threshold value set, the more frequently update instructions are output from the control target value update instruction unit 6e to the control target value storage unit 6b.

[0041] When setting a threshold value based on the condition that soil or sand discharged from the bucket 4c deviates from the tray area 14a, for example, the distance between the center of the toe of the bucket 4c and the center point 14c of the tray area 14a at the start of the discharge operation (bucket dump) can be defined as the discharge position deviation, and the movement amount and turning angle of the traveling vehicle 5 that cause a predetermined set distance of soil or sand displacement can be set as the threshold value. As an example, the set distance for the soil or sand displacement can be set to 50% of the width of the bucket 4c. When the hydraulic excavator 1 loads soil or sand into the dump truck 11, in order to efficiently fully load the dump truck 11, it is necessary to accurately discharge the soil or sand at the center point 14c of the tray area 14a. If the bucket 4c deviates from the center point 14c during discharge, soil or sand may spill from the tray, which may prevent the dump truck 11 from being fully loaded or require more discharges than necessary, thereby reducing productivity. Therefore, setting the threshold value based on the size of the bucket 4c is a reasonable example for maintaining high productivity.

[0042] <Operation> Fig. 4 is a flowchart showing an example of a processing procedure by the control device 6. The processing in Fig. 4 is executed by the control device 6 while the control device 6 is energized.

[0043] When a start signal is received from a key switch (not shown) provided in the operator's cab 2 or from the remote operation device 100, the control device 6 starts the process of FIG. 4 in step S100.

[0044] In step S101, the control device 6 detects the dump truck 11 from the distance data obtained by measuring the distance around the vehicle and received from the object detection device 8 using the control target value acquisition unit 6a.

[0045] In the following step S102, the control device 6 calculates a vector 14b, which is the relative distance to the center point 14c of the tray area 14a of the dump truck 11, by the control target value acquisition unit 6a.

[0046] When the procedure proceeds to step S103, the control device 6 determines whether the vehicle 5 is stopped and whether movement or turning of the vehicle 5 is detected by the relative information change detection unit 6d. If the vehicle 5 is displaced even though it is stopped, the control device 6 calculates the amount of displacement and transmits it to the control target value update instruction unit 6e. Specifically, step S103 includes determining whether the vehicle 5 is stopped (step S103a) and determining whether the vehicle 5 has been displaced (step S103b). If the vehicle 5 is intentionally driven based on the output signal of the travel sensor 10b (no), the control device 6 returns the procedure from step S103a to step S101, detects the dump truck 11, and recalculates the vector 14b. If the vehicle 5 is not intentionally driven (yes), the control device 6 calculates the position and orientation of the vehicle 5 based on the output of the positioning device 9 or the object detection device 8, and determines whether they differ from the position and orientation of the vehicle 5 currently stored in memory (S103b). As a result, if the running body 5 has been displaced (yes), the control device 6 proceeds from step S103b to step S104, and if no displacement of the running body 5 has occurred (no), the control device 6 skips steps S103b to S104 and proceeds to step S105.

[0047] When the procedure proceeds to step S104, the control device 6 executes the determination of the above-mentioned formula 1 using the control target value update instruction unit 6e to determine whether or not the relative distance data currently stored in the control target value storage unit 6b needs to be updated. If step S103b is performed multiple times while the traveling object 5 is currently stopped, the total value of the displacement amounts from multiple times is substituted for the displacement amount in formula 1. If the condition of formula 1 is not met and updating of the relative distance data is not necessary (no), the control device 6 proceeds from step S104 to step S105. Conversely, if the condition of formula 1 is met and updating of the relative distance data is necessary (yes), the control device 6 proceeds from step S104 to step S106.

[0048] When the procedure proceeds to step S105, the control device 6 retains the relative distance data currently retained in the control target value retaining unit 6b.

[0049] When the procedure proceeds to step S106, the control device 6 transmits an instruction to update the relative distance data from the control target value update instruction unit 6e to the control target value storage unit 6b, transmits an instruction to recalculate the relative distance data from the control target value storage unit 6b to the control target value acquisition unit 6a, and updates the relative distance data currently stored in the control target value storage unit 6b with the relative distance data newly calculated by the control target value acquisition unit 6a. As the processing of step S106, a processing of returning the procedure to step S101 is illustrated in FIG.

[0050] If necessary, the processing of step S106 is performed and the reliability of the relative distance data is confirmed in step S105, after which the control device 6 proceeds to step S107, where it calculates control signals for the rotating body 3 and front work machine 4 that realize automatic excavation and loading or semi-automatic excavation and loading based on the latest highly reliable relative distance data stored in the control target value storage unit 6b, and outputs control signals to the drive devices 7a, 7b.

[0051] In the following step S108, the control device 6 determines whether operation of the hydraulic excavator 1 has ended, and if operation is to be continued (no), the procedure returns to step S103a, and if operation is to be ended (yes), the procedure in Fig. 2 ends. The control device 6 can determine whether operation has ended, for example, based on a signal that is input when a key switch provided in the operator's cab 2 is turned off, or a signal that commands the end of operation that is transmitted from a remote control device.

[0052] By repeatedly executing the above steps S100-S108, the excavation and loading operation is repeated without recalculating the relative distance data as long as the running body 5 does not displace beyond the threshold value (step S107), and as a result, if the running body 5 displaces beyond the threshold value, the relative distance data is recalculated and the excavation and loading operation is performed.

[0053] <Remote Control Device> As illustrated in FIG. 1 , elements corresponding to the cab 2 and the control device 6 may be located outside the body of the hydraulic excavator 1. The remote operation device 100 illustrated in FIG. 1 is an example of the cab 2 and the control device 6 installed outside the hydraulic excavator 1. The remote operation device 100 has an operation device (not shown) corresponding to the operation device provided in the cab 2 and a remote control device 101 corresponding to the control device 6, and is installed in a location separate from the operation site of the hydraulic excavator 1, for example, a server room capable of wireless communication with the hydraulic excavator 1. An operator boards the remote operation device 100 in the server room and operates the operation device while viewing camera images transmitted from the hydraulic excavator 1, and the hydraulic excavator 1 operates in accordance with operation signals transmitted from the remote control device 101 to the hydraulic excavator. The remote control device 101 can execute the same processes as the control device 6, except that it receives output signals from various sensors and outputs command signals to the drive devices 7 a and 7 b via wireless communication.

[0054] <Effect> When the hydraulic excavator 1 excavates the ground, the traveling body 5 slides along the ground and is pulled to the excavation site due to the reaction between the ground and the hydraulic excavator 1. Generally, the traveling body 5 is not driven during excavation and is therefore stationary, but the relative positions of the hydraulic excavator 1 and the dump truck 11 change unexpectedly due to the sliding of the traveling body 5, and the reference coordinate system 13 ( FIG. 2 ) of the hydraulic excavator 1 moves in the on-site coordinate system 15 as shown by the thick arrow in FIG. 5 .

[0055] However, because this movement of the reference coordinate system 13 is not based on an instruction from the operator or the control device 6, if the device distance data update process is not performed, automatic loading control will be performed in a state where the identified relative position is deviated from the actual relative position of the hydraulic excavator 1 and the dump truck 11. In other words, as shown in Fig. 5, automatic loading control will be performed in a state where the tray area 14a recognized by the control device is deviated from the actual tray position of the dump truck 11. In this case, soil and sand may spill from the dump truck 11, reducing productivity.

[0056] In contrast, in this embodiment, even if the hydraulic excavator 1 moves unintentionally due to an excavation reaction force, if a predetermined unintended displacement of the traveling body 5 is detected, the relative distance data is recalculated, thereby maintaining high productivity through highly accurate excavation and loading control based on highly reliable relative distance data. Furthermore, as long as a predetermined unintended displacement of the traveling body 5 is not detected, excavation and loading control is repeatedly performed without calculating the relative distance data each time, and by reducing the frequency of calculation of the relative distance data, the calculation load on the control device 6 is reduced, allowing for smooth operation of the hydraulic excavator 1. Therefore, as described above, a certain level of reliability of the relative distance data is ensured when the bucket 4c starts to move, so the bucket 4c can be moved to the target position along a trajectory calculated in advance, thereby reducing wasted operation of the hydraulic excavator 1.

[0057] As described above, the hydraulic excavator 1 of this embodiment can suppress discrepancies in the perception of the actual positional relationship with the dump truck 11, and can load soil and gravel onto the transport vehicle with high accuracy while moving the bucket on a trajectory with minimal loss, thereby maintaining high productivity.

[0058] Second Embodiment Fig. 6 is a flowchart showing an example of a processing procedure by a control device provided in a work machine according to a second embodiment of the present invention. Processing that is the same as in the first embodiment is given the same step numbers as in Fig. 4, and explanations thereof will be omitted where appropriate.

[0059] This embodiment differs from the first embodiment in that the motion detection sensor 10a is used as a displacement sensor, and the need to update the relative distance data (data on the position of the target object) is determined based on the number of excavation operations detected by the motion detection sensor 10a while the traveling object 5 is stopped. In this embodiment, the amount of displacement of the traveling object 5 is converted into the number of excavation operations, taking into account that the traveling object 5 may be displaced for each excavation operation. Except for this point, this embodiment is similar to the first embodiment, including the hardware configuration.

[0060] 4, steps S100-S103a and S105-S108 are the same as those in the first embodiment. In this embodiment, if the determination in step S103a is affirmative, the control device 6 proceeds to step S104', where the relative information change detection unit 6d detects an excavation operation by the front work unit 4 based on a detection signal from the operation detection sensor 10a related to the operation of the front work unit 4. If the number of excavation operations while the traveling unit 5 is currently stopped reaches a preset number of times as a threshold, the control device 6 determines that the traveling unit 5 has been displaced by more than the threshold while the traveling unit 5 is currently stopped. If the number of excavation operations is equal to or greater than the preset number (yes), the control device 6 proceeds from step S104' to step S106, where the relative distance data is updated. If the number of excavation operations is less than the preset number (no), the control device 6 proceeds from step S104' to step S105, where the current relative distance data is retained.

[0061] As described above, the sensors related to the operation of the front working implement 4 can be at least one of pressure sensors that detect the pressure in the bottom-side oil chamber and rod-side oil chamber of the hydraulic cylinder that drives the front working implement, such as the boom cylinder 4d, an angle sensor that detects the angle of the driven member of the front working implement 4, such as the boom 4a, an IMU, an operation sensor that detects an operation signal, etc.

[0062] As an example, when a pressure sensor is used, it is possible to determine that an excavation operation has been performed based on the output signal of the pressure sensor during the last operation of the hydraulic excavator (step S107) before execution of step S104', for example, by detecting an excavation reaction force equal to or greater than a set value based on the oil chamber pressure of the arm cylinder 4e during arm crowding.When an angle sensor, IMU, or operation sensor is used, it is possible to determine the excavation operation based on the trajectory and operation pattern of the bucket 4c calculated based on the output signals of these sensors during operation of the hydraulic excavator.

[0063] The above-mentioned set number of times as a threshold value can be set by taking statistics in advance on the displacement amount of the running body 5 per excavation operation and determining the number of excavation operations at which the displacement amount of the running body 5 reaches the threshold value.

[0064] In this embodiment, the same effects as in the first embodiment can be obtained.

[0065] 7 is a flowchart showing an example of a processing procedure by a control device provided in a work machine according to a third embodiment of the present invention. The same steps as in the first embodiment are assigned the same step numbers as in FIG. 4, and descriptions thereof will be omitted where appropriate.

[0066] This embodiment differs from the first embodiment in that the motion detection sensor 10a is used as a displacement sensor, and whether or not the relative distance data (data on the position of the target object) needs to be updated is determined based on the presence or absence of a specific motion detected by the motion detection sensor 10a while the running object 5 is stopped. The specific motion is, for example, a motion that tilts the running object 5, and a representative example is a jack-up motion.

[0067] If the amount of lifting of the boom 4a of the front work implement 4 is small during ground leveling, the bucket 4c is pressed against the ground, and the reaction force between the front work implement 4 and the ground causes the front of the traveling unit 5 to lift up, resulting in a jack-up operation. When the traveling unit 5 is tilted in this manner, the contact area between the traveling unit 5 and the ground is reduced, making the traveling unit more likely to slide on the ground due to the movement of the front work implement 4 and the rotating unit 3. This causes the traveling unit 5 to move or turn even when the traveling unit 5 is not moving. When a specific operation that tilts the traveling unit 5, such as this jack-up operation, is performed, there is a possibility that the traveling unit 5 will be displaced (particularly turning) beyond a threshold value. Taking this into consideration, in this embodiment, when a specific operation that may cause the traveling unit 5 to move significantly is detected, it is deemed that the traveling unit 5 has been displaced beyond a threshold value. Except for this point, this embodiment, including the hardware configuration, is the same as the first embodiment.

[0068] 4, steps S100-S103a and S105-S108 are the same as those in the first embodiment. In this embodiment, if the determination in step S103a is satisfied, the control device 6 proceeds to step S104'', where the relative information change detection unit 6d detects a specific movement by the front working implement 4 based on the detection signal from the movement detection sensor 10a related to the movement of the front working implement 4, and if the specific movement is detected, the control device 6 determines that the moving object 5 has been displaced by more than a threshold value while the moving object 5 is currently stopped. If the specific movement is detected (yes), the control device 6 proceeds from step S104'' to step S106, where the relative distance data is updated, and if the specific movement is not detected (no), the control device 6 proceeds from step S104'' to step S105, where the current relative distance data is retained.

[0069] The sensors used to determine specific operations can include at least one of a pressure sensor that detects the pressure in the bottom oil chamber and rod oil chamber of the hydraulic cylinder that drives the front working equipment such as the boom cylinder 4d, an operation sensor that detects an operation signal, an IMU that detects the acceleration of the rotating body 3 and the running body 5, a positioning device 9, an object detection device 8, etc.

[0070] As an example, when a pressure sensor or an operation sensor is used, if the pressure in the rod-side oil chamber of the boom cylinder 4d (the oil chamber to which pressurized oil is supplied when the boom is raised) falls below a set value while the boom is being raised, based on the output signals from the pressure sensor and the operation sensor during the last operation of the hydraulic excavator (step S107) before execution of step S104", it can be inferred that a jack-up operation has been performed unintentionally and the bucket 4c has been pressed hard against the ground. Furthermore, if the pressure in the rod-side oil chamber of the boom cylinder 4d (the oil chamber from which pressurized oil is pushed out when the boom is lowered) falls below a set value while the amount of boom-lowering operation exceeds a set value, it can be inferred that a jack-up operation has been performed intentionally. When an IMU, positioning device 9, or object detection device 8 is used, it can be determined that a specific operation has been performed based on the inclination of the traveling body 5 calculated based on the output signals from these sensors while the hydraulic excavator is in operation.

[0071] In this embodiment, the same effects as in the first embodiment can be obtained.

[0072] (Modifications) The above embodiments can be combined as appropriate. For example, when the first embodiment and the second embodiment are combined, if the determination in step S104 of FIG. 4 is not satisfied (no), a flow in which step S104′ (FIG. 6) is further executed can be adopted. When the first embodiment and the third embodiment are combined, if the determination in step S104 of FIG. 4 is not satisfied (no), a flow in which step S104″ (FIG. 7) is further executed can be adopted. When three embodiments are combined, if the determination in step S104 of FIG. 4 is not satisfied (no), a flow in which step S104′ (FIG. 6) and step S104″ (FIG. 7) can further be executed can be adopted.

[0073] 1...hydraulic excavator (work machine), 3...swivel, 4...front work machine, 4c...bucket, 5...traveling body, 6...control device, 7...driving device, 8...object detection device (displacement sensor), 9...positioning device (displacement sensor), 10a...motion detection sensor (displacement sensor), 10b...traveling sensor, 12...specific area (object), 14a...tray area (object), 101...remote control device

Claims

1. A work machine comprising a running body, a rotating body rotatably provided on the upper part of the running body, and a front work machine attached to the rotating body, comprising: an object detection device which detects objects around the work machine; a running sensor which detects the movement of the running body; a displacement sensor which detects the displacement of the running body; a drive device which drives the running body, the rotating body, and the front work machine; and a control device which controls the drive device based on the detection results of the object detection device, the running sensor, and the displacement sensor, wherein the control device calculates the position of an object which serves as a reference for control of the running body, the rotating body, and the front work machine based on a detection signal from the object detection device, controls the rotating body and the front work machine based on the position of the object, and recalculates the position of the object based on the detection signals from the running sensor and the displacement sensor if the running body is displaced while the operation of the running body is stopped.

2. A work machine as described in claim 1, wherein the displacement sensor is at least one of a positioning device that acquires the position of the rotating body and the object detection device, and the control device calculates the amount of displacement of the traveling body based on the detection signals of at least one of the positioning device and the object detection device.

3. A work machine as claimed in claim 1, characterized in that the displacement sensor is a motion detection sensor which detects the motion of the front work machine, and the control device detects excavation motion by the front work machine based on the detection signal of the motion detection sensor, and when the number of excavation motions while the running body remains stopped reaches a preset number, determines that the running body has been displaced by a threshold value or more while the running body remains stopped.

4. A work machine as described in claim 1, wherein the displacement sensor is a motion detection sensor which detects the motion of the front work implement, and the control device detects a specific motion based on a detection signal from the motion detection sensor, and when the specific motion is detected, determines that the running body has been displaced by a threshold value or more while the running body remains stopped.

5. A work machine according to claim 3, wherein the threshold value is a value at which the bucket of the front work machine deviates from the area of ​​the object.

6. A remote control device that communicates with a work machine having a running body, a rotating body rotatably provided on the upper part of the running body, a front work machine attached to the rotating body, an object detection device that detects surrounding objects, a running sensor that detects the movement of the running body, a displacement sensor that detects the displacement of the running body, and a drive unit that drives the running body, the rotating body, and the front work unit, and remotely controls the drive unit based on detection results of the object detection device, the running sensor, and the displacement sensor, characterized in that the remote control device calculates a position of an object that serves as a reference for control of the running body, the rotating body, and the front work unit based on a detection signal of the object detection device received from the work machine, generates control signals for the rotating body and the front work unit based on the position of the object and transmits them to the work machine, and recalculates the position of the object based on the detection signals of the running sensor and the displacement sensor received from the work machine if the running body is displaced while the operation of the running body is stopped.

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