Operation system and control method

Abstract

To reduce the fall of sediment between excavation and soil discharge.SOLUTION: A stage identification unit identifies a working stage of a work machine. The target determination unit determines a target posture of boom and arm based on the identified work stage. A control volume calculator calculates the control volume of the boom and arm based on the target posture. A limiting unit limits the control amount of the arm so that the change in the control amount of the arm is within a predetermined change when the identified work stage is the work stage for hoist swing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an operating system and a control method. [Background technology]

[0002] Patent Document 1 discloses technology related to the automatic operation of a hydraulic excavator. In the automatic operation of a hydraulic excavator, if the soil held in the bucket spills out during swing, work efficiency decreases. Patent Document 1 discloses technology in which, in order to prevent the soil from spilling, the excess soil held in the bucket is dropped after excavation is completed before swinging. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-115272 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in view of work efficiency, it is preferable to load as much earth and sand as possible in one swing and loading operation, so it is required to perform hoist swing after excavation without dropping as much earth and sand as possible. An object of the present disclosure is to provide a work system and a control method that can prevent soil from falling during the period from excavation to soil removal. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, a work system is a control device for a work machine equipped with a boom, an arm, and a bucket, and includes a stage identification unit that identifies a work stage of the work machine, a target determination unit that determines a target attitude of the boom and the arm based on the identified work stage, a control amount calculation unit that calculates control amounts of the boom and the arm based on the target attitude, and a limiting unit that, when the identified work stage is a work stage related to hoist rotation, limits the control amount of the arm so that a change in the control amount of the arm is within a predetermined change amount. [Effects of the Invention]

[0006] According to the above aspect, it is possible to prevent earth and sand from falling during the period from excavation by the work machine to earth removal. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram showing the configuration of a work system according to a first embodiment. [Figure 2] 1 is an external view of a work machine according to a first embodiment. [Figure 3] 1 is a schematic block diagram showing the configuration of a control device according to a first embodiment. [Figure 4] FIG. 1 is a diagram illustrating an example of a travel route. [Figure 5] 1 is a schematic block diagram showing the configuration of a control device for a work machine according to a first embodiment. [Figure 6] FIG. 3 is a diagram showing an example of a path of a bucket before excavation in automatic excavation and loading control according to the first embodiment. [Figure 7] FIG. 4 is a diagram showing an example of a path of a bucket after excavation in the automatic excavation and loading control according to the first embodiment. [Figure 8] FIG. 2 is a state transition diagram showing the transition of work stages according to the first embodiment. [Figure 9] FIG. 4 is a block diagram showing the operation of a restriction unit 1221 according to the first embodiment. [Figure 10]5 is a flowchart showing a method for outputting an automatic excavation and loading instruction by the control device according to the first embodiment. [Figure 11] 5 is a flowchart showing the operation of the work machine according to the first embodiment when it receives an input of an automatic excavation and loading instruction. DETAILED DESCRIPTION OF THE INVENTION

[0008] First Embodiment <Work System 1> FIG. 1 is a schematic diagram showing the configuration of a work system according to a first embodiment. The work system 1 includes a work machine 100, one or more transport vehicles 200, and a control device 300. The work system 1 is an unmanned transport system in which the work machine 100 and the transport vehicles 200 are automatically controlled by the control device 300.

[0009] The haulage vehicle 200 travels unmanned based on course data (e.g., speed data, coordinates of where the haulage vehicle 200 should go) received from the control device 300. The haulage vehicle 200 and the control device 300 are connected by communication via an access point 400. The control device 300 acquires the position and direction from the haulage vehicle 200 and generates course data to be used for the travel of the haulage vehicle 200 based on the acquired position and direction. The control device 300 transmits the course data to the haulage vehicle 200. The haulage vehicle 200 travels unmanned based on the received course data. Note that although the work system 1 according to the first embodiment includes an unmanned transport system, in other embodiments, some or all of the haulage vehicles 200 may be operated by a driver. In this case, the control device 300 does not need to transmit the course data and instructions regarding loading, but acquires the position and direction of the haulage vehicle 200.

[0010] The work machine 100 is unmanned and controlled in accordance with instructions received from the control device 300. The work machine 100 and the control device 300 are connected by communication via an access point 400.

[0011] The work machine 100 and the haul vehicle 200 are provided at a work site (for example, a mine or a quarry). On the other hand, the control device 300 may be provided at any location. For example, the control device 300 may be provided at a location away from the work machine 100 and the haul vehicle 200 (for example, in a city or within the work site).

[0012] 《Transport Vehicle 200》 The transport vehicle 200 according to the first embodiment is a dump truck equipped with a vessel (loading container) 201. Note that the transport vehicle 200 according to other embodiments may be a transport vehicle other than a dump truck. The haulage vehicle 200 includes a vessel 201, a position and orientation calculator 210, and a control device 220. The position and orientation calculator 210 calculates the position and orientation of the haulage vehicle 200. The position and orientation calculator 210 includes two receivers that receive positioning signals from artificial satellites that make up a Global Navigation Satellite System (GNSS). An example of a GNSS is the Global Positioning System (GPS). The two receivers are installed at different positions on the haulage vehicle 200. The position and orientation calculator 210 detects the position of the haulage vehicle 200 in a site coordinate system based on the positioning signals received by the receivers. The position and orientation calculator 210 uses the positioning signals received by the two receivers to calculate the orientation of the haulage vehicle 200 as the relationship between the installation position of one receiver and the installation position of the other receiver. In other embodiments, the present invention is not limited to this, and for example, the transport vehicle 200 may be equipped with an inertial measurement unit (IMU), and the orientation may be calculated based on the measurement results of the inertial measurement unit. In this case, drift of the inertial measurement unit may be corrected based on the travel trajectory of the transport vehicle 200.

[0013] The control device 220 transmits the position and direction detected by the position and direction calculator 210 to the control device 300. The control device 220 receives course data and instructions for unloading, instructions for entering the loading point P3, and instructions for departing from the loading point P3 from the control device 300. The control device 220 causes the haulage vehicle 200 to travel in accordance with the received course data, or raises or lowers the vessel 201 of the haulage vehicle 200 in accordance with the instructions for unloading. When the haulage vehicle reaches the destination and stops in accordance with the instructions, the control device 220 transmits an arrival notification indicating arrival at the destination to the control device 300.

[0014] "Work Machine 100" FIG. 2 is an external view of the work machine 100 according to the first embodiment. The work machine 100 according to the first embodiment is a hydraulic excavator. Note that the work machine 100 according to other embodiments may be a work vehicle other than a hydraulic excavator. The work machine 100 includes a hydraulically operated work implement 110, a rotating body 120 that supports the work implement 110, and a running body 130 that supports the rotating body 120.

[0015] The work implement 110 includes a boom 111 , an arm 112 , a bucket 113 , a boom cylinder 114 , an arm cylinder 115 , a bucket cylinder 116 , a boom angle sensor 117 , an arm angle sensor 118 , and a bucket angle sensor 119 .

[0016] The base end of the boom 111 is attached to the front of the rotating body 120 via a pin. The arm 112 connects the boom 111 and the bucket 113. The base end of the arm 112 is attached to the tip of the boom 111 via a pin. The bucket 113 includes a blade for excavating materials such as earth and sand, and a container for transporting the excavated materials. The base end of the bucket 113 is attached to the tip of the arm 112 via a pin.

[0017] The boom cylinder 114 is a hydraulic cylinder for operating the boom 111. A base end of the boom cylinder 114 is attached to the rotating body 120. A tip end of the boom cylinder 114 is attached to the boom 111. The arm cylinder 115 is a hydraulic cylinder for driving the arm 112. A base end of the arm cylinder 115 is attached to the boom 111. A tip end of the arm cylinder 115 is attached to the arm 112. The bucket cylinder 116 is a hydraulic cylinder for driving the bucket 113. A base end of the bucket cylinder 116 is attached to the arm 112. A tip end of the bucket cylinder 116 is attached to a bucket link mechanism, and operates the bucket 113 via the bucket link mechanism.

[0018] The boom angle sensor 117 is attached to the boom 111 and detects the tilt angle of the boom 111 . The arm angle sensor 118 is attached to the arm 112 and detects the tilt angle of the arm 112 . The bucket angle sensor 119 is attached to the bucket 113 and detects the inclination angle of the bucket 113 . The boom angle sensor 117, arm angle sensor 118, and bucket angle sensor 119 according to the first embodiment detect the inclination angle relative to the horizontal ground. Note that the angle sensors according to other embodiments are not limited to this, and may detect the inclination angle relative to another reference plane. For example, in other embodiments, the angle sensor may detect a relative angle based on the mounting portion, or may detect the inclination angle by measuring the stroke of each cylinder and converting the cylinder stroke into an angle. The inclination angle and stroke amount (cylinder length) of the boom 111, arm 112, and bucket 113 represent the attitude of the boom 111, arm 112, and bucket 113.

[0019] The work machine 100 is equipped with a position and orientation calculator 123 , an inclination measuring device 124 , and a control device 125 .

[0020] The position and orientation calculator 123 calculates the position of the revolving unit 120 and the orientation in which the revolving unit 120 faces. The position and orientation calculator 123 is equipped with two receivers that receive positioning signals from artificial satellites that make up the GNSS. The two receivers are installed at different positions on the revolving unit 120. The position and orientation calculator 123 detects the position of a representative point of the revolving unit 120 (the center of rotation of the revolving unit 120) in the on-site coordinate system based on the positioning signal received by one of the receivers. The position and direction calculator 123 uses the positioning signals received by the two receivers to calculate the direction in which the rotating unit 120 faces as the relationship between the installation position of one receiver and the installation position of the other receiver.

[0021] The inclination measuring device 124 measures the acceleration and angular velocity of the revolving unit 120, and detects the attitude (e.g., roll angle, pitch angle, yaw angle) of the revolving unit 120 based on the measurement results. The inclination measuring device 124 is installed, for example, on the underside of the revolving unit 120. The inclination measuring device 124 can be, for example, an inertial measurement unit (IMU).

[0022] The control device 125 transmits the rotation speed, position, and orientation of the rotating unit 120, the tilt angles of the boom 111, the arm 112, and the bucket 113, the traveling speed of the traveling unit 130, and the attitude of the rotating unit 120 to the control device 300. Hereinafter, data collected by the work machine 100 or the transport vehicle 200 from various sensors is also referred to as vehicle data. Note that vehicle data in other embodiments is not limited to this. For example, vehicle data in other embodiments may not include any of the rotation speed, position, orientation, tilt angle, traveling speed, and attitude, may include values ​​detected by other sensors, or may include values ​​calculated from the detected values. Note that the control device 125 can convert a position in the site coordinate system to a position in the machine coordinate system and vice versa by using the position of the representative point of the rotating unit 120 in the site coordinate system detected by the position / orientation calculator 123 and the orientation and attitude of the rotating unit 120 related to the vehicle data. The control device 125 receives control instructions from the control device 300. The control device 125 drives the work machine 110, the revolving body 120, or the traveling body 130 in accordance with the received control instructions. When driving based on the control instructions is completed, the control device 125 transmits a completion notification to the control device 300. The detailed configuration of the control device 125 will be described later.

[0023] 《Control device 300》 FIG. 3 is a schematic block diagram showing the configuration of a control device 300 according to the first embodiment. The control device 300 manages the operation of the work machine 100 and the travel of the haulage vehicle 200. The control device 300 is a computer equipped with a processor 310, a main memory 330, a storage 350, and an interface 370. The storage 350 stores programs. The processor 310 reads the programs from the storage 350, loads them into the main memory 330, and executes processing in accordance with the programs. The control device 300 is connected to a network via the interface 370. Examples of the processor 310 include a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), and a microprocessor.

[0024] The program may be for realizing some of the functions to be performed by the computer of the control device 300. For example, the program may be combined with other programs already stored in the storage 350 or other programs implemented in other devices to perform the functions. In other embodiments, the control device 300 may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions realized by the processor 310 may be realized by the integrated circuit. Such an integrated circuit is also an example of a processor.

[0025] The storage 350 has storage areas serving as a control position storage unit 351 and a travel route storage unit 352. Examples of the storage 350 include a magnetic disk, a magneto-optical disk, an optical disk, and a semiconductor memory. The storage 350 may be an internal medium directly connected to the common communication line of the control device 300, or may be an external medium connected to the control device 300 via the interface 370. The storage 350 is a non-transitory tangible storage medium.

[0026] The control position storage unit 351 stores position data of the digging point P22 and the loading point P3. The digging point P22 and the loading point P3 are points that are set in advance by an operation by, for example, a manager of the work site.

[0027] FIG. 4 is a diagram showing an example of a travel route R. The travel route memory unit 352 stores a travel route R for each haulage vehicle 200. The travel route R includes a predetermined connecting route R1 connecting two areas A (for example, a loading site A1 and an unloading site A2), as well as an entrance route R2, an approach route R3, and an exit route R4, which are routes within area A. The entrance route R2 is a route that connects a waiting point P1, which is one end of the connecting route R1, to a predetermined turning point P2 within area A. The approach route R3 is a route that connects the turning point P2 to a loading point P3 or an unloading point P4 within area A. The exit route R4 is a route that connects a loading point P3 or an unloading point P4 within area A to an exit point P5, which is the other end of the connecting route R1. The turning point P2 is a point that is set by the control device 300 according to the position of the loading point P3. The control device 300 calculates the approach route R2, the approach route R3, and the exit route R4 every time the loading point P3 is changed.

[0028] The processor 310 is provided with a collection unit 311, a transport vehicle identification unit 312, a travel course generation unit 313, a notification receiving unit 314, a loading container identification unit 315, and an automatic excavation and loading instruction unit 316 by executing a program.

[0029] The collection unit 311 receives vehicle data from the work machine 100 and the haulage vehicle 200 via the access point 400 .

[0030] The transport vehicle identification unit 312 identifies the transport vehicle 200 to be loaded with the excavated material based on the vehicle data of the transport vehicle 200 collected by the collection unit 311.

[0031] The travel course generation unit 313 generates course data indicating an area in which the transport vehicle 200 is permitted to move, based on the travel route R stored in the travel route storage unit 352 and the vehicle data collected by the collection unit 311, and transmits the course data to the transport vehicle 200. The course data is, for example, data indicating an area in which the transport vehicle 200 can travel at a predetermined speed within a certain time period and which does not overlap with the travel route R of another transport vehicle 200.

[0032] The notification receiving unit 314 receives a completion notification from the work machine 100 and an arrival notification from the haulage vehicle 200.

[0033] When the loading container identification unit 315 receives a notification from the transport vehicle 200 that the transport vehicle 200 has arrived at the loading point P3, it identifies the position of the vessel 201 in the site coordinate system based on the vehicle data of the transport vehicle 200. The loading container identification unit 315 identifies the position of the vessel 201 in the site coordinate system, for example, by arranging three-dimensional data representing the outline of the vessel 201 at the position indicated by the position data of the transport vehicle 200 and rotating it in the direction indicated by the orientation data of the transport vehicle 200. The loading container identification unit 315 transmits the identified position of the vessel 201 to the work machine 100.

[0034] The automatic digging and loading instruction unit 316 transmits to the work machine 100 an automatic digging and loading instruction including the position of the digging point P22 and the position of the loading point P3 stored in the control position storage unit 351.

[0035] <<Control device 125 of work machine 100>> FIG. 5 is a schematic block diagram showing the configuration of the control device 125 of the work machine 100 according to the first embodiment. The control device 125 controls the actuators of the work machine 100 based on instructions from the control device 300 . The control device 125 is a computer including a processor 1210, a main memory 1230, a storage 1250, and an interface 1270. The storage 1250 stores a program. The processor 1210 reads the program from the storage 1250, loads it into the main memory 1230, and executes processing in accordance with the program. The control device 125 is connected to a network via the interface 1270. Examples of the processor 1210 include a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), and a microprocessor.

[0036] The program may be for realizing some of the functions to be performed by the computer of the control device 125. For example, the program may be for realizing the functions by combining it with other programs already stored in the storage 1250 or with other programs implemented in other devices. Note that in other embodiments, the control device 125 may include a custom LSI such as a PLD in addition to or instead of the above configuration. In this case, some or all of the functions realized by the processor 1210 may be realized by the integrated circuit. Such an integrated circuit is also included as an example of a processor.

[0037] Examples of storage 1250 include a magnetic disk, a magneto-optical disk, an optical disk, a semiconductor memory, etc. Storage 1250 may be an internal medium directly connected to a common communication line of control device 125, or may be an external medium connected to control device 125 via interface 1270. Storage 1250 is a non-transitory tangible storage medium.

[0038] By executing a program, the processor 1210 is provided with a vehicle data acquisition unit 1211, an attitude identification unit 1212, an instruction receiving unit 1213, a loading container identification unit 1214, an avoidance position identification unit 1215, an excavation position identification unit 1216, a start position determination unit 1217, a stage identification unit 1218, a target determination unit 1219, a control amount calculation unit 1220, a restriction unit 1221, a command generation unit 1222, and a command output unit 1223.

[0039] The vehicle data acquisition unit 1211 acquires vehicle data from various sensors equipped in the work machine 100 and transmits the acquired vehicle data to the control device 300.

[0040] The attitude identification unit 1212 identifies the position of the bucket 113 in a machine coordinate system based on the work machine 100, based on the vehicle data acquired by the vehicle data acquisition unit 1211. The attitude identification unit 1212 identifies the positions of multiple points on the contour of the bucket 113, including the cutting edge and the bottom. Specifically, the attitude identification unit 1212 identifies the positions of the boom 111, the arm 112, and the bucket 113 in the following procedure. The attitude identification unit 1212 identifies the pitch angle of the revolving unit 120 acquired by the vehicle data acquisition unit 1211. The attitude identification unit 1212 calculates the absolute angle of the boom 111 based on the inclination angle of the boom 111 and the pitch angle of the revolving unit 120. The inclination angle is an angle with respect to the horizontal plane, and the absolute angle is an angle based on the machine coordinate system. The attitude identification unit 1212 calculates the position of the tip of the boom 111 based on the absolute angle of the boom 111 and the known length of the boom 111 (the distance from the pin at the base end to the pin at the tip end). The attitude identification unit 1212 calculates the absolute angle of the arm 112 based on the pitch angle of the revolving unit 120 and the inclination angle of the arm 112. The posture identification unit 1212 determines the position of the tip of the arm 112 based on the position of the tip of the boom 111, the absolute angle of the arm 112, and the known length of the arm 112 (the distance from the pin at the base end to the pin at the tip). The attitude identification unit 1212 determines the absolute angle of the bucket 113 based on the pitch angle of the revolving unit 120 and the tilt angle of the bucket 113. The attitude identification unit 1212 determines the positions of multiple points on the contour of the bucket 113 based on the position of the tip of the arm 112, the absolute angle of the bucket 113, and the distances from the pin of the bucket 113 to multiple points on the contour of the bucket 113.

[0041] The instruction receiving unit 1213 receives an automatic excavation and loading instruction from the control device 300. Upon receiving the automatic excavation and loading instruction, the instruction receiving unit 1213 determines to start automatic excavation and loading control. The automatic excavation and loading control includes automatic soil removal control. In other words, the instruction receiving unit 1213 is an example of an automatic control determination unit that determines whether to start automatic soil removal control.

[0042] The loading container identification unit 1214 receives the position of the vessel 201 of the transport vehicle 200 from the control device 300, and converts the position of the vessel 201 from the site coordinate system to the machine coordinate system based on the vehicle data acquired by the vehicle data acquisition unit 1211.

[0043] FIG. 6 is a diagram showing an example of a path of the bucket 113 before excavation in the automatic excavation and loading control according to the first embodiment. The avoidance position specifying unit 1215 specifies an interference avoidance position P02, which is a point where the work machine 110 and the haulage vehicle 200 do not interfere with each other in a plan view from above, based on the position of the work machine 100, the position of the vessel 201, and the position of the pin of the bucket 113 at the start of control (empty swing start position P01). The interference avoidance position P02 has the same height as the empty swing start position P01, is the same distance from the center of rotation of the rotating unit 120 as the distance from the center of rotation to the empty swing start position P01, and is a position below which the haulage vehicle 200 does not exist. For example, the avoidance position specifying unit 1215 specifies a circle whose center is the center of rotation of the rotating unit 120 and whose radius is the distance between the center of rotation and the empty rotation start position P01, and specifies, among the positions on the circle, the position where the outline of the bucket 113 does not interfere with the haulage vehicle 200 in a plan view from above and which is closest to the empty rotation start position P01 as the interference avoidance position P02. The avoidance position specifying unit 1215 can determine whether or not the haulage vehicle 200 and the bucket 113 will interfere with each other based on the position of the haulage vehicle 200 and the positions of multiple points on the outline of the bucket 113. Here, "the same height" and "equal distance" do not necessarily mean that the height or distance is completely the same, but rather allow for some error or margin.

[0044] The excavation position identification unit 1216 identifies, as the excavation position P05, point P2 that is away from the excavation point P22 included in the automatic excavation and loading instruction by the distance from the pin to the cutting edge of the bucket 113. In other words, when the bucket 113 is in a predetermined excavation posture with the cutting edge facing in the dumping direction, when the cutting edge of the bucket 113 is located at the excavation point P22, the pin of the bucket 113 is located at the excavation position P05. Furthermore, the excavation position specifying unit 1216 determines a position that is a predetermined height above the excavation position P05 as the turning end position P04.

[0045] FIG. 7 is a diagram showing an example of a path of the bucket 113 after excavation in the automatic excavation and loading control according to the first embodiment. The start position determination unit 1217 determines the unloading start position P07 based on the position of the vessel 201. Specifically, the start position determination unit 1217 determines the height of the unloading start position P07 to be the height of the vessel 201 plus the height of the bucket 113 and the height of the control margin of the bucket 113.

[0046] The stage identification unit 1218 identifies the work stage of the work machine 100 based on the vehicle data acquired by the vehicle data acquisition unit 1211. The work stages include a down swing stage, an excavation stage, a hoist swing stage, and an earth removal stage. Hoist swing is an operation in which the boom 111 is raised while the rotating body 120 is rotated to move the bucket 113 above the vessel 201. Down swing is an operation in which the boom 111 is lowered while the rotating body 120 is rotated to move the bucket 113 to an excavation position. A method for identifying the work stage by the stage identification unit 1218 will be described later.

[0047] The target determination unit 1219 determines target inclination angles of the boom 111, the arm 112, and the bucket 113 in accordance with the work stage of the work machine 100. Each target inclination angle is expressed as an angle with respect to the ground plane. Specifically, the target determination unit 1219 determines the target inclination angles of the boom 111 and the arm 112 in the down swing stage so that the position of the tip of the arm 112 is at excavation position P05. The target determination unit 1219 also determines the target inclination angle of the bucket 113 in the down swing stage so that the angle of the bucket 113 is a predetermined angle suitable for the next excavation. In the excavation stage, the target determination unit 1219 sequentially calculates a target path of the cutting edge of the bucket 113 so that the bucket 113 can excavate a predetermined amount of soil, and determines the target inclination angles of the boom 111, the arm 112, and the bucket 113 based on the target path. The target determination unit 1219 determines the target tilt angles of the boom 111 and the arm 112 in the hoist rotation phase so that the position of the tip of the arm 112 is the discharge start position P07. In the discharge phase, the target determination unit 1219 determines the target tilt angle of the bucket 113 to a predetermined discharge completion angle. The target tilt angle is an example of a target attitude.

[0048] The control amount calculation unit 1220 calculates the control amounts of the boom 111, arm 112, and bucket 113 based on the vehicle data acquired by the vehicle data acquisition unit 1211 and the target tilt angle determined by the target determination unit 1219. Specifically, the control amount calculation unit 1220 determines the control amounts of the boom 111, arm 112, and bucket 113 by inputting the difference between the measured tilt angle of the boom 111, arm 112, and bucket 113 and the target tilt angle into a predetermined function. In this function, the difference between the measured tilt angle and the target tilt angle and the control amount have a monotonically increasing relationship. "Monotonically increasing" means that when one value increases, the other value always increases or does not change (monotonically non-decreasing). Note that when the work stage is the hoist rotation stage, the command generation unit 1222 determines the control amount of the bucket 113 so that the ground angle of the bucket 113 does not change even when the boom 111 and arm 112 are driven.

[0049] When the work stage identified by the stage identification unit 1218 is the hoist rotation stage, the limiting unit 1221 limits the control amount of the arm 112 calculated by the control amount calculation unit 1220 so that the amount of change is within a predetermined upper limit value of the amount of change. The detailed behavior of the limiting unit 1221 will be described later.

[0050] When the instruction receiving unit 1213 receives an excavation and loading instruction, the command generating unit 1222 generates a swing command, a boom command, an arm command, and a bucket command based on the control amount of the work implement 110 calculated by the control amount calculating unit 1220 or limited by the limiting unit 1221. Furthermore, when the work stage is the down swing stage, the command generating unit 1222 temporarily stops the boom 111 and the arm 112 when the height of the pin of the bucket 113 becomes the same height as the swing end position P04, and then further drives the boom 111 and the arm 112 after the tip of the arm 112 reaches the swing end position P04. When the work stage is the excavation stage, the command generating unit 1222 generates an arm command to rotate the arm 112 in the pulling direction in addition to a bucket command to rotate the bucket 113 in the excavation direction. The command output unit 1223 outputs a rotation command, a boom command, an arm command, and a bucket command.

[0051] FIG. 8 is a state transition diagram showing the transition of work stages according to the first embodiment. When the instruction receiving unit 1213 receives an input of an automatic excavation and loading instruction from the control device 300 and automatic excavation and loading control is started, the stage specifying unit 1218 transitions the work stage to the down swing stage Ph1.

[0052] When the work stage is the down swing stage Ph1, the stage identification unit 1218 maintains the down swing stage Ph1 when the distance between the position of the tip of the arm 112 and the excavation position P05 is equal to or greater than a predetermined threshold. On the other hand, when the work stage is the down swing stage Ph1, the stage identification unit 1218 transitions the work stage to the excavation stage Ph2 when the distance between the position of the tip of the arm 112 and the excavation position P05 becomes less than the predetermined threshold.

[0053] When the work stage is the excavation stage Ph2, the stage identification unit 1218 maintains the excavation stage Ph2 if the difference between the tilt angle of the bucket 113 and the excavation completion angle is equal to or greater than a predetermined threshold. The excavation completion angle is the angle of the bucket 113 with respect to the ground plane at the time of excavation completion. On the other hand, when the work stage is the excavation stage Ph2, the stage identification unit 1218 transitions the work stage to the hoist rotation stage Ph3 if the difference between the tilt angle of the bucket 113 and the excavation completion angle becomes less than a predetermined threshold.

[0054] When the work stage is the hoist rotation stage Ph3, the stage identification unit 1218 maintains the hoist rotation stage Ph3 when the distance between the position of the tip of the arm 112 and the discharge start position P07 is equal to or greater than a predetermined threshold. On the other hand, when the work stage is the hoist rotation stage Ph3, the stage identification unit 1218 transitions the work stage to the discharge stage Ph4 when the distance between the position of the tip of the arm 112 and the discharge start position P07 becomes less than a predetermined threshold.

[0055] When the work stage is the soil unloading stage Ph4, the stage identification unit 1218 maintains the soil unloading stage Ph4 if the difference between the tilt angle of the bucket 113 and the soil unloading completion angle is equal to or greater than a predetermined threshold. The soil unloading completion angle is the angle of the bucket 113 with respect to the ground plane at the time of soil unloading completion. On the other hand, when the work stage is the soil unloading stage Ph4, the stage identification unit 1218 transitions the work stage to the down swing stage Ph1 if the difference between the tilt angle of the bucket 113 and the soil unloading completion angle is less than a predetermined threshold and the number of loadings is less than a predetermined number. On the other hand, when the work stage is the soil unloading stage Ph4, the stage identification unit 1218 determines that the automatic excavation and loading operation has ended if the difference between the tilt angle of the bucket 113 and the soil unloading completion angle is less than a predetermined threshold and the number of loadings is equal to the predetermined number.

[0056] Configuration of Restriction Unit 1221 FIG. 9 is a block diagram showing the operation of the limiter 1221 according to the first embodiment. The limiting unit 1221 includes a delay block B1, a subtraction block B2, an upper limit value output block B3, a comparison block B4, an addition block B5, and a switch block B6.

[0057] The delay block B1 delays the signal output by the switch block B6 by a unit time and outputs the delayed signal. In other words, the delay block B1 outputs the previous control amount of the arm 112.

[0058] The subtraction block B2 outputs a value obtained by subtracting the previous control amount, which is the output value of the delay block B1, from the newly input control amount of the arm 112. In other words, the subtraction block B2 outputs the change amount of the control amount of the arm 112.

[0059] The upper limit output block B3 always outputs the upper limit value of the change amount of the control amount of the arm 112 in the hoist rotation stage.

[0060] The comparison block B4 outputs the result of comparing the amount of change in the controlled variable of the arm 112, which is the output value of the subtraction block B2, with the amount of change upper limit, which is the output value of the upper limit value output block B3. The comparison block B4 outputs 1 when the amount of change in the controlled variable is equal to or greater than the amount of change upper limit, and outputs 0 when the amount of change in the controlled variable is less than the amount of change upper limit. In other words, the comparison block B4 determines whether the amount of change in the controlled variable of the arm 112 is equal to or greater than the amount of change upper limit.

[0061] The addition block B5 outputs a value obtained by adding the previous control amount, which is the output value of the delay block B1, and the change upper limit value, which is the output value of the upper limit value output block B3. In other words, the addition block B5 outputs a control amount that is increased by the change upper limit value from the previous control amount.

[0062] Based on the output of the comparison block B4, the switch block B6 outputs either the newly input control amount of the arm 112 or the output value of the addition block B5. Specifically, when the output of the comparison block B4 is 1, the switch block B6 outputs the output value of the addition block B5. When the output of the comparison block B4 is 0, the switch block B6 outputs the newly input control amount of the arm 112. In other words, when the change in the control amount is equal to or greater than the change amount upper limit, the switch block B6 outputs the control amount that is increased by the change amount upper limit from the previous control amount. On the other hand, when the change in the control amount is less than the change amount upper limit, the switch block B6 outputs the control amount.

[0063] By having such a configuration, the limiting unit 1221 limits the control amount of the arm 112 calculated by the control amount calculating unit 1220 so that the amount of change is within a predetermined upper limit value of the amount of change.

[0064] Automatic excavation and loading control FIG. 10 is a flowchart showing a method for outputting an automatic excavation and loading instruction by the control device 300 according to the first embodiment. When the notification receiving unit 314 of the control device 300 receives a notification from the transport vehicle 200 that the transport vehicle has arrived at the loading point P3 (step S1), the loading container identifying unit 1214 acquires vehicle data from the transport vehicle 200 (step S2). The loading container identifying unit 1214 identifies the position of the vessel 201 in the site coordinate system based on the acquired vehicle data (step S3). The loading container identifying unit 1214 transmits the identified position of the vessel 201 to the work machine 100. The automatic digging and loading instruction unit 316 reads out the positions of the digging point P22 and the loading point P3 from the control position memory unit 351 (step S4). The automatic digging and loading instruction unit 316 transmits an automatic digging and loading instruction including the read-out positions of the digging point P22 and the loading point P3 to the work machine 100 (step S5).

[0065] FIG. 11 is a flowchart showing the operation of the work machine 100 according to the first embodiment when it receives an input of an automatic digging and loading command. When the instruction receiving unit 1213 of the control device 125 receives an input of an automatic excavation and loading instruction from the control device 300, the control device 125 executes the processing shown in FIG.

[0066] The vehicle data acquisition unit 1211 acquires the position and orientation of the revolving unit 120, the tilt angles of the boom 111, the arm 112, and the bucket 113, and the attitude of the revolving unit 120 (step S101). The vehicle data acquisition unit 1211 identifies the position of the center of rotation of the revolving unit 120 based on the acquired position and orientation of the revolving unit 120 (step S102).

[0067] The loading container identification unit 1214 acquires the position of the vessel 201 in the site coordinate system from the control device 300 (step S103). The loading container identification unit 1214 converts the position of the vessel 201 from the site coordinate system to the machine coordinate system based on the position, orientation, and attitude of the rotating unit 120 acquired in step S101 (step S104).

[0068] The posture identification unit 1212 determines the position of the pin of the bucket 113 at the time of input of the automatic excavation and loading command as the empty swing start position P01 based on the vehicle information acquired in step S101 (step S105). The avoidance position identification unit 1215 determines the interference avoidance position P02 based on the empty swing start position P01 determined in step S105 and the position of the vessel 201 determined in step S104 (step S106). The excavation position identification unit 1216 determines the excavation position P05 and the swing end position P04 based on the position of the excavation point P22 included in the automatic excavation and loading command (step S107). The start position determination unit 1217 determines the earth unloading start position based on the position of the vessel 201 determined in step S104, the movement distance of the lowest point of the bucket 113 due to the automatic earth unloading control calculated in advance, and the number of times the transport vehicle 200 is loaded (step S108).

[0069] Next, the stage identifying unit 1218 identifies the work stage based on the determination method shown in Fig. 8 (step S109). The work stage immediately after the start of the automatic excavation and loading process is the down swing stage. The target determination unit 1219 determines a target attitude of the work machine 100 according to the work stage identified in step S109 (step S110). The control amount calculation unit 1220 calculates control amounts for the boom 111, the arm 112, the bucket 113, and the rotating body 120 based on the target attitude determined in step S110 and the vehicle data acquired by the vehicle data acquisition unit 1211 (step S111).

[0070] The limiting unit 1221 determines whether the work stage identified in step S109 is the hoist rotation stage (step S112). If the control stage is the hoist rotation stage, the limiting unit 1221 limits the control amount of the arm 112 calculated in step S111 so that the change amount is within the change amount upper limit value (step S113). The command generating unit 1222 generates a boom command, an arm command, a bucket command, and a swing command based on the calculated control amount (step S114). The command output unit 1223 outputs the swing command, boom command, arm command, and bucket command generated in step S114 (step S115).

[0071] Next, the command output unit 1223 determines whether the work stage identified in step S109 is in the final stage (step S116). If the work stage is not in the final stage (step S116: NO), the vehicle data acquisition unit 1211 acquires new vehicle data (step S117) and returns the process to step S109. On the other hand, if the work stage is at the final stage (step S116: YES), the command output unit 1223 transmits a notification of completion of the automatic excavation and loading control to the control device 300 (step S118), and ends the process.

[0072] Actions and Effects In this way, when the work stage is the hoist rotation stage, the work system 1 according to the first embodiment limits the amount of change in the control amount of the arm 112 to within the upper limit of the amount of change. This enables the work machine 100 to prevent earth and sand from falling during the period from excavation to earth removal.

[0073] Here, the reason why the falling of earth and sand can be suppressed by limiting the control amount of the arm 112 during the hoist rotation stage will be explained.

[0074] A work machine 100 such as a backhoe excavator performs excavation by moving the cutting edge of the bucket 113 rearward, i.e., by moving the work implement 110 in the pulling direction. Therefore, when the work machine 100 finishes excavating, the bucket 113 is generally located near the rotating unit 120. At this time, the arm 112 may be tilted toward the rotating unit 120 rather than vertical. The position of the tip of the arm 112 decreases as the angle approaches vertical. Therefore, when the arm 112 is tilted toward the rotating unit 120, if the arm 112 is driven in the pushing direction, the bucket 113 will temporarily descend and then rise. Therefore, if the control amount is not limited, the weight of the bucket 113 and the soil will cause the bucket 113 to move at high speed when the hoist starts to swing, which could result in the soil spilling.

[0075] In contrast, the work system 1 according to the first embodiment limits the control amount of the arm 112 during the hoist rotation stage, thereby reducing the movement speed of the bucket 113. This allows the work system 1 to prevent earth and sand from falling even when the hoist starts to rotate.

[0076] Other Embodiments Although one embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design modifications are possible. That is, in other embodiments, the order of the above-described processes may be changed as appropriate. Furthermore, some processes may be executed in parallel.

[0077] The control device 125 and management device 300 according to the above-described embodiments may each be configured by a single computer, or the configuration of the control device 125 or management device 300 may be divided among multiple computers, and the multiple computers may cooperate with each other to function as the control device 125 or management device 300. In this case, some of the computers that make up the management device 300 may be mounted inside the work machine 100, and other computers may be provided outside the work machine 100. Also, some of the computers that make up the control device 125 may be mounted inside the work machine 100, and other computers may be provided outside the work machine 100.

[0078] Furthermore, the control device 125 according to the above-described embodiment always limits the control amount of the arm 112 to within the upper limit of the amount of change during the hoist rotation stage, but this is not limited to this. For example, the control device 125 according to another embodiment may limit the control amount to within the upper limit of the amount of change only when the angle of the arm 112 is tilted toward the rotating body 120 from the vertical. [Explanation of symbols]

[0079] 1...Work system 100...Work machine 110...Work implement 111...Boom 112...Arm 113...Bucket 125...Control device 220...Control device 1218...Stage specification unit 1219...Target determination unit 1220...Control amount calculation unit 1221...Restriction unit

Claims

1. A control device for a work machine having a vehicle body, a boom, an arm, and a bucket, a target determination unit that determines a target attitude of the boom and the arm; a control amount calculation unit that calculates control amounts for the boom and the arm so that the attitudes of the boom and the arm coincide with the target attitudes; a limiting unit that limits the control amount of the arm so that a change amount of a newly input control amount of the arm relative to a control amount of the arm in a previous control cycle is within a predetermined change amount when the angle of the arm is inclined toward the vehicle body from the vertical; A working system comprising:

2. a posture acquisition unit that acquires measurement values ​​of the postures of the boom and the arm, The control amount calculation unit calculates control amounts for the boom and the arm based on the measured value of the attitude and the target attitude. The work system according to claim 1 .

3. Equipped with a stage identification unit that identifies the work stage The work system according to claim 1 .

4. The change amount is the control amount per time of the limit amount of the arm. The work system according to claim 1 .

5. The control amount calculation unit calculates the control amount that indicates the drive speed of the boom and the arm. The work system according to claim 4 .

6. The control amount monotonically increases with the difference between the measured value of the attitude and the target attitude. The work system according to claim 5 .

7. The target determination unit determines a target attitude of the boom and the arm based on a work stage. The work system according to claim 1 .

8. The limiting unit limits the control amount of the arm when the work stage relates to hoist rotation. The work system according to claim 7 .

9. The limiting unit limits the control amount of the arm when the angle of the arm is inclined toward a rotating body to which the boom is attached from the vertical. The work system according to claim 1 .

10. A method for controlling a work machine having a body, a boom, an arm, and a bucket, comprising: determining a target attitude of the boom and the arm; calculating control amounts for the boom and the arm so that the attitudes of the boom and the arm coincide with the target attitude; a step of limiting the control amount of the arm so that, when the angle of the arm is inclined toward the vehicle body from the vertical, a change amount of a newly input control amount of the arm relative to a control amount in a previous control cycle of the arm is within a predetermined change amount; A control method comprising:

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