Work machine, control method, and work system

Abstract

A body of this work machine includes a first body and a second body that turns with respect to the first body. An actuator drives and turns the second body with respect to the first body. A first sensor is provided on the body and acquires first measurement data, which is positioning data. A controller executes turning control using the actuator on the basis of the first measurement data. The controller determines whether or not the turning control is executable on the basis of the accuracy of the first measurement data.

Description

Work machine, control method and work system

[0001] This application claims priority to Japanese Patent Application No. 2023-203056, filed November 30, 2023, the contents of which are incorporated herein by reference.

[0002] Patent Document 1 discloses technology relating to automatic earth removal control of a work machine. The automatic earth removal control disclosed in Patent Document 1 automatically controls the work machine to turn toward the transport vehicle and to position the bucket above the vessel of the transport vehicle, based on measurement data from a Global Navigation Satellite System (GNSS) that indicates the position and orientation of the work machine.

[0003] Japanese Patent Application Laid-Open No. 2019-065661

[0004] The accuracy of GNSS measurements varies depending on the number of artificial satellites from which signals can be received. The number of artificial satellites from which signals can be received varies depending on the time of day and the surrounding terrain. In GNSS measurements, when a fixed solution can be obtained, the measurement error is several centimeters, but when a fixed solution cannot be obtained and only a float solution can be obtained, the measurement error is several tens of centimeters to several meters. If the error is large, the work machine cannot be controlled correctly, and unintended behavior such as contact between the work machine and the transport vehicle may occur.

[0005] An example of an object of the present disclosure is to provide a work machine, a control method, and a work system that can prevent unintended behavior during swing control.

[0006] According to one aspect of the present disclosure, a work machine comprises a main body having a first main body and a second main body that rotates relative to the first main body, an actuator that drives the second main body to rotate relative to the first main body, a GNSS sensor provided on the main body that acquires first measurement data that is positioning data, and a controller that executes rotation control by the actuator based on the first measurement data, and that determines whether or not to execute the rotation control based on the accuracy of the first measurement data.

[0007] According to the above aspect, as one example, it is possible to prevent unintended behavior caused by the accuracy of the measurement data.

[0008] FIG. 1 is a schematic diagram showing the configuration of a work machine according to a first embodiment. FIG. 2 is a diagram showing the internal configuration of a cab according to the first embodiment. FIG. 3 is a schematic block diagram showing the configuration of a control device according to the first embodiment. FIG. 4 is a diagram showing an example of the movement of the work machine during a first swing according to the first embodiment. FIG. 5 is a diagram showing an example of the movement of the work machine during a second swing according to the first embodiment. FIG. 6 is a flowchart showing data collection processing by the control device according to the first embodiment. FIG. 7 is a flowchart showing automatic control by the control device according to the first embodiment. FIG. 8 is a schematic diagram showing the configuration of a work machine according to a third embodiment. FIG. 9 is a schematic block diagram showing the configuration of a control device according to the third embodiment. FIG. 10 is a flowchart showing data collection processing by the control device according to the third embodiment. FIG. 11 is a flowchart showing automatic control by the control device according to the third embodiment.

[0009] First Embodiment Hereinafter, an embodiment will be described in detail with reference to the drawings.

[0010] <Configuration of Work Machine 100> Figure 1 is a schematic diagram showing the configuration of a work machine 100 according to a first embodiment. The work machine 100 operates at a construction site, excavates a work object such as earth and sand, and loads the excavated material as cargo onto a loading platform such as a vessel of a loading object T such as a dump truck. Examples of the work machine 100 include a face shovel, a backhoe shovel, and a rope shovel. The work machine 100 may be electrically driven or hydraulically driven. The work machine 100 according to the first embodiment is a backhoe shovel. The work machine 100 includes a traveling body 110, a revolving body 120, a work implement 130, and a cab 140. Examples of the loading object T include a dump truck and a hopper.

[0011] The running body 110 supports the work machine 100 so that it can travel. The running body 110 is equipped with two caterpillar tracks 111, one on the left and one on the right, and two travel motors 112 for driving each caterpillar track 111. The running body 110 is an example of a support unit. The running body 110 is an example of a first main body. The rotating body 120 is supported on the running body 110 so that it can rotate about a rotation center. The rotating body 120 is an example of a second main body. The running body 110 and the rotating body 120 form the main body of the work machine 100. The work implement 130 is driven hydraulically. The work implement 130 is supported on the front part of the rotating body 120 so that it can be driven in the vertical direction. The cab 140 is a space where an operator sits and operates the work machine 100. The cab 140 is provided on the left front part of the rotating body 120. Here, the portion of the revolving unit 120 to which the work machine 130 is attached is referred to as the front portion. Furthermore, with respect to the revolving unit 120, the portion opposite the front portion is referred to as the rear portion, the left portion as the left portion, and the right portion as the right portion.

[0012] <Configuration of the Swing Unit 120> The swing unit 120 includes an engine 121, a hydraulic pump 122, a control valve 123, and a swing motor 124. The engine 121 is a prime mover that drives the hydraulic pump 122. The engine 121 is an example of a power source. The hydraulic pump 122 is a variable displacement pump driven by the engine 121. The hydraulic pump 122 supplies hydraulic oil to each actuator (boom cylinder 131C, arm cylinder 132C, bucket cylinder 133C, travel motor 112, and swing motor 124) via a control valve 123. The control valve 123 controls the flow rate of hydraulic oil supplied from the hydraulic pump 122. The swing motor 124 is driven by hydraulic oil supplied from the hydraulic pump 122 via the control valve 123, causing the swing unit 120 to swing.

[0013] <Configuration of Work Machine 130> The work machine 130 includes a boom 131, an arm 132, a bucket 133 as a work implement, a boom cylinder 131C, an arm cylinder 132C, and a bucket cylinder 133C. Other examples of the work implement include tip attachments such as a clam bucket, a tilt bucket, a tilt rotate bucket, a grapple, and a lifting magnet.

[0014] The base end of the boom 131 is rotatably attached to the revolving unit 120 via a boom pin. Note that in the work machine 100 shown in FIG. 1 , the boom 131 is provided in the center portion of the front of the revolving unit 120, but this is not limited thereto. The boom 131 may be attached offset in the left-right direction. In this case, the center of rotation of the revolving unit 120 is not located on the operating plane of the work implement 130. The boom 131 may be a bendable two-piece boom or an extendable offset boom. The arm 132 connects the boom 131 and the bucket 133. The base end of the arm 132 is rotatably attached to the tip of the boom 131 via an arm pin. The bucket 133 is rotatably attached to the tip of the arm 132 via a pin. The boom 131 and the arm 132 are members that support the bucket 133. The bucket 133 functions as a container for collecting excavated soil and sand. The bucket 133 is attached so that its opening faces the rotating body 120 (rearward).

[0015] The boom cylinder 131C is a hydraulic cylinder for operating the boom 131. A base end of the boom cylinder 131C is attached to the revolving unit 120. A tip end of the boom cylinder 131C is attached to the boom 131. The arm cylinder 132C is a hydraulic cylinder for driving the arm 132. A base end of the arm cylinder 132C is attached to the boom 131. A tip end of the arm cylinder 132C is attached to the arm 132. The bucket cylinder 133C is a hydraulic cylinder for driving the bucket 133. A base end of the bucket cylinder 133C is attached to the arm 132. A tip end of the bucket cylinder 133C is attached to a link mechanism that rotates the bucket 133.

[0016] <Configuration of Cab 140> FIG. 2 is a diagram showing the internal configuration of the cab 140 according to the first embodiment. A driver's seat 141, an operation terminal 142, and an operation device 143 are provided in the cab 140. The operation terminal 142 is provided near the driver's seat 141 and serves as a user interface with the control device 160, which will be described later. The operation terminal 142 is a display device configured, for example, with a touch panel, and may have an operation unit operated by an operator and an input reception unit that receives operations. The display device also displays measurement data from an engine water temperature gauge, a fuel gauge, and the like. The operation terminal 142 may also have a display unit such as an LCD. The touch panel is an example of a display unit.

[0017] The operation device 143 is a device for driving the traveling body 110, the revolving body 120, and the work machine 130 through manual operation by an operator. The operation device 143 includes a left operation lever 143LO, a right operation lever 143RO, a left foot pedal 143LF, a right foot pedal 143RF, a left travel lever 143LT, a right travel lever 143RT, a teaching switch 143TS, and a start switch 143SW.

[0018] The left operating lever 143LO is provided on the left side of the driver's seat 141. The right operating lever 143RO is provided on the right side of the driver's seat 141.

[0019] The left operation lever 143LO is an operation mechanism for performing the swing operation of the revolving unit 120 and the excavation / dump operation of the arm 132. Specifically, when the operator of the work machine 100 tilts the left operation lever 143LO forward, the arm 132 performs a dump operation. When the operator of the work machine 100 tilts the left operation lever 143LO rearward, the arm 132 performs an excavation operation. When the operator of the work machine 100 tilts the left operation lever 143LO to the right, the revolving unit 120 swings to the right. When the operator of the work machine 100 tilts the left operation lever 143LO to the left, the revolving unit 120 swings to the left. Note that in other embodiments, the revolving unit 120 may swing to the right or left when the left operation lever 143LO is tilted forward or backward, and the arm 132 may perform an excavation or dump operation when the left operation lever 143LO is tilted left or right.

[0020] The right operating lever 143RO is an operating mechanism for performing the excavation / dumping operation of the bucket 133 and the raising / lowering operation of the boom 131. Specifically, when the operator of the work machine 100 tilts the right operating lever 143RO forward, the boom 131 is lowered. When the operator of the work machine 100 tilts the right operating lever 143RO rearward, the boom 131 is raised. When the operator of the work machine 100 tilts the right operating lever 143RO to the right, the bucket 133 is dumped. When the operator of the work machine 100 tilts the right operating lever 143RO to the left, the bucket 133 is excavated. Note that in other embodiments, when the right operating lever 143RO is tilted forward or backward, the bucket 133 may be dumped or excavated, and when the right operating lever 143RO is tilted left or right, the boom 131 may be raised or lowered.

[0021] The left foot pedal 143LF is located on the left side of the floor in front of the driver's seat 141. The right foot pedal 143RF is located on the right side of the floor in front of the driver's seat 141. The left travel lever 143LT is pivotally supported by the left foot pedal 143LF, and is configured so that tilting the left travel lever 143LT and pushing down the left foot pedal 143LF are linked. The right travel lever 143RT is pivotally supported by the right foot pedal 143RF, and is configured so that tilting the right travel lever 143RT and pushing down the right foot pedal 143RF are linked.

[0022] The left foot pedal 143LF and left travel lever 143LT correspond to the rotational drive of the left crawler belt of the traveling body 110. Specifically, when the operator of the work machine 100 pushes the left foot pedal 143LF or the left travel lever 143LT forward, the left crawler belt rotates in the forward direction. Conversely, when the operator of the work machine 100 pushes the left foot pedal 143LF or the left travel lever 143LT backward, the left crawler belt rotates in the reverse direction.

[0023] The right foot pedal 143RF and right travel lever 143RT correspond to the rotational drive of the right crawler of the running body 110. Specifically, when the operator of the work machine 100 pushes the right foot pedal 143RF or the right travel lever 143RT forward, the right crawler rotates in the forward direction. Conversely, when the operator of the work machine 100 pushes the right foot pedal 143RF or the right travel lever 143RT backward, the right crawler rotates in the reverse direction.

[0024] The teaching switch 143TS is provided, for example, on the handle portion of the right operating lever 143RO. The teaching switch 143TS may be located near the operator seated in the driver's seat 141. When the teaching switch 143TS is pressed, the control device 160 stores the posture of the work machine 100 at the time the switch was pressed as a reference for automatic control.

[0025] The start switch 143SW is provided, for example, on the handle portion of the right operating lever 143RO. The start switch 143SW may be located near the operator seated in the driver's seat 141. When the start switch 143SW is pressed, an automatic control instruction signal is output to the control device 160. When the control device 160 receives the input of the automatic control instruction signal, it starts automatic control.

[0026] Automatic control refers to autonomous control by the work machine 100 of the drive of the work implement 130 and the rotating unit 120 to achieve a predetermined operation. In the first embodiment, the automatic control is performed autonomously by the work machine 100. The first rotation is a series of operations in which the bucket 133 is positioned to the side of the loading target T due to excavation of the excavation target, and the boom 131 is raised while the bucket 133 is rotated to a direction facing the loading target T. The second rotation is a series of operations in which the bucket 133 is positioned above the loading target T due to loading, and the boom 131 is lowered while the bucket 133 is rotated to a predetermined direction. The side of the loading target T refers to the outside of a loading platform, such as a vessel, onto which cargo is loaded. Note that automatic control according to other embodiments may involve only the second rotation. In the first embodiment, the target orientation of the rotating unit 120 and the target attitude of the bucket 133 during the first rotation and the second rotation are predetermined orientations and attitudes, respectively. Note that the excavation target is typically located lower than the height of the loading target T. Therefore, the work machine 100 controls the drive of the work machine 130 during the first swing and the second swing so that the loading target T does not come into contact with the work machine 130. Details of the automatic control will be described later. Each time the start switch 143SW is pressed, the automatic control that is executed switches between the first swing and the second swing. In another embodiment, the operation device 143 may be provided with two start switches 143SW, each assigned to the first swing and the second swing.

[0027] <Configuration of Measurement System> As shown in FIG. 1 , the work machine 100 is equipped with a position and orientation calculator 151 , an inclination measuring device 152 , a boom stroke sensor 153 , an arm stroke sensor 154 , and a bucket stroke sensor 155 .

[0028] The position and orientation calculator 151 calculates the position of the revolving unit 120 and the orientation in which the revolving unit 120 faces. The position and orientation calculator 151 includes two receivers that receive positioning signals from artificial satellites that make up the Global Navigation Satellite System (hereinafter referred to as GNSS). The two receivers are installed at different positions on the revolving unit 120. Note that the mounting positions of the two receivers shown in FIG. 1 are just an example, and the mounting positions of the two receivers may be any positions known to the position and orientation calculator 151. For example, the two receivers may be mounted diagonally on the revolving unit 120. The position and orientation calculator 151 detects the position of a representative point of the revolving unit 120 (the origin of the excavator coordinate system) in the site coordinate system based on the positioning signals received by the receivers. The position and orientation calculator 151 uses the positioning signals received by the two receivers to calculate the orientation of the revolving unit 120 as the relationship between the installation position of one receiver and the installation position of the other receiver. The orientation of the revolving unit 120 is the direction perpendicular to the front of the revolving unit 120. The position and orientation calculator 151 is an example of a first sensor that acquires positioning data.

[0029] The inclinometer 152 measures the acceleration and angular velocity of the rotating unit 120, and detects the attitude (roll angle, pitch angle) and rotation speed of the rotating unit 120 based on the measurement results. The inclinometer 152 is installed, for example, on the underside of the rotating unit 120. The inclinometer 152 can be, for example, an inertial measurement unit (IMU).

[0030] The boom stroke sensor 153 is attached to the boom cylinder 131C and detects the cylinder length of the boom cylinder 131C. The cylinder length of the boom cylinder 131C can be converted into the relative angle of the boom 131 with respect to the revolving unit 120. The arm stroke sensor 154 is attached to the arm cylinder 132C and detects the cylinder length of the arm cylinder 132C. The cylinder length of the arm cylinder 132C can be converted into the relative angle of the arm 132 with respect to the boom 131. The bucket stroke sensor 155 is attached to the bucket cylinder 133C and detects the cylinder length of the bucket cylinder 133C. The cylinder length of the bucket cylinder 133C can be converted into the relative angle of the bucket 133 with respect to the arm 132. The work machine 100 according to the first embodiment uses the boom stroke sensor 153, the arm stroke sensor 154, and the bucket stroke sensor 155 to identify the angle of each link component of the work implement 130, but this is not limited to this in other embodiments. For example, in other embodiments, instead of the stroke sensor, a potentiometer that detects the relative rotation angle of the link parts may be provided, or an inclination sensor that detects the angle of each link part relative to the ground may be provided.

[0031] <Configuration of the Control Device 160> FIG. 3 is a schematic block diagram showing the configuration of the control device 160 according to the first embodiment. The work machine 100 is equipped with the control device 160. The control device 160 may be implemented in the operation terminal 142, or may be provided separately from the operation terminal 142 and receive input and output from the operation terminal 142. The control device 160 receives operation signals from the operation device 143. The control device 160 drives the work implement 130, the revolving body 120, and the traveling body 110 by outputting the received operation signals or operation signals generated for automatic control to the control valve 123. Hereinafter, operation signals received from the operation device 143 will also be referred to as manual operation signals, and operation signals generated for automatic control will also be referred to as automatic operation signals. Note that automatic operation signals consist of operation signals that drive the revolving body 120 and the work implement 130, but do not include operation signals that drive the traveling body 110. If a manual operation signal from the operator is received during automatic control, the control device 160 may stop the automatic control.

[0032] The control device 160 is a computer including a processor 610, a main memory 630, a storage 650, and an interface 670. The storage 650 stores a program. The processor 610 reads the program from the storage 650, loads it into the main memory 630, and executes processing in accordance with the program.

[0033] Examples of storage 650 include semiconductor memory, magnetic disks, magneto-optical disks, optical disks, etc. Storage 650 may be an internal medium directly connected to a common communication line of control device 160, or may be an external medium connected to control device 160 via interface 670. Main memory 630 and storage 650 are non-transitory tangible storage media.

[0034] By executing a program, the processor 610 is equipped with a measurement data acquisition unit 611, a direction accuracy determination unit 612, an alternative direction calculation unit 613, an operation signal input unit 614, a work machine position identification unit 615, a reference identification unit 616, an angle identification unit 617, a movement control unit 618, and an operation signal output unit 619.

[0035] The measurement data acquisition unit 611 acquires measurement data from the measurement system of the work machine 100. Specifically, the measurement data acquisition unit 611 acquires measurement data from the position and orientation calculator 151, the inclination measuring device 152, the boom stroke sensor 153, the arm stroke sensor 154, and the bucket stroke sensor 155.

[0036] The alternative orientation calculation unit 613 calculates alternative orientation data indicating the orientation of the rotating unit 120 at the current time based on the GNSS measurement data when the last fix solution was obtained and the measurement data of the inclinometer 152 acquired from the time the last fix solution was obtained to the current time. The alternative orientation data is orientation data to be used in place of the GNSS measurement data when the accuracy of the orientation indicated by the latest GNSS measurement data is insufficient for automatic control (when the GNSS measurement data is not a fix solution). The alternative orientation calculation unit 613 can obtain the rotation angle from the time the last fix solution was obtained to the current time by integrating the yaw angular velocity indicated by the measurement data of the inclinometer 152 acquired from the time the last fix solution was obtained to the current time. By adding the rotation angle to the GNSS measurement data when the last fix solution was obtained, the alternative orientation data indicating the orientation of the rotating unit 120 at the current time can be calculated.

[0037] The azimuth accuracy determination unit 612 determines whether the accuracy of the GNSS measurement data is sufficient for automatic control based on the GNSS measurement data acquired by the measurement data acquisition unit 611. If the calculation results of the horizontal position and altitude indicated by the GNSS measurement data acquired from the position and orientation calculator 151 are fix solutions, the azimuth accuracy determination unit 612 determines that the accuracy of the GNSS measurement data is sufficient for automatic control. On the other hand, if the calculation results of the horizontal position or altitude indicated by the GNSS measurement data acquired from the position and orientation calculator 151 are not fix solutions (float solutions), the azimuth accuracy determination unit 612 determines that the accuracy of the GNSS measurement data is insufficient for automatic control. In addition, the azimuth accuracy determination unit 612 determines whether the accuracy of the alternative orientation data calculated by the alternative orientation calculation unit 613 is sufficient for automatic control. The azimuth accuracy determination unit 612 determines that the accuracy of the alternative azimuth data is insufficient when a predetermined time has elapsed since the fix solution could not be obtained. The predetermined time is set, for example, to a time such that the accumulated error of the inclinometer 152 does not exceed a margin considered for the reference point of automatic control.

[0038] The operation signal input unit 614 receives input of operation signals manually operated by the operator from the operation device 143. The operation signals include a drive signal for raising or lowering the boom 131, a drive signal for raising or lowering the arm 132, a drive signal for dumping or digging the bucket 133, a drive signal for turning the rotating unit 120 right or left, a drive signal for operating the traveling unit 110 to travel, and an automatic control instruction signal for the work machine 100.

[0039] The work implement position identifying unit 615 identifies the position of the tip P of the arm 132 ( FIG. 4 ) and the position of the lowest point Q of the bucket 133 ( FIG. 4 ) in the vehicle body coordinate system based on the revolving unit 120, based on the measurement data acquired by the measurement data acquiring unit 611. The lowest point Q of the bucket 133 refers to the point on the outer shape of the bucket 133 that is the shortest distance from the ground surface.

[0040] The work implement position identifying unit 615 determines the vertical and horizontal components of the length of the boom 131 based on the inclination angle of the boom 131 and the known length of the boom 131 (the distance from the pin at the base end to the pin at the tip end). Similarly, the work implement position identifying unit 615 determines the vertical and horizontal components of the length of the arm 132. The work implement position identifying unit 615 identifies, as the position of the tip P of the arm 132, a position that is away from the position of the work machine 100 in a direction identified from the orientation and posture of the work machine 100 by the sum of the vertical and horizontal components of the lengths of the boom 131 and the arm 132. The work implement position identifying unit 615 also identifies the position of the lowest point Q of the bucket 133 based on the inclination angle of the bucket 133 and the known shape of the bucket 133. For example, the work implement position identifying unit 615 calculates the position of each of a plurality of points on the outer shell of the bucket 133 based on the tilt angle of the bucket 133, and identifies the point with the lowest height among the plurality of points as the lowest point Q. Furthermore, for example, the work implement position identifying unit 615 may determine the lowest point Q as a point obtained by offsetting the distance between the bucket pin and a point on the bucket 133 that is farthest from the bucket pin downward in the height direction from the bucket pin. Furthermore, for example, the work implement position identifying unit 615 may determine the lowest point Q as a point obtained by offsetting the maximum amount of the bucket movable range downward in the height direction from the bucket pin. Furthermore, the work implement position identifying unit 615 may determine the lowest point Q as a point obtained by offsetting a height with a margin from the height identified above, taking into account control errors and GNSS measurement errors.

[0041] Before executing automatic control, the reference identification unit 616 receives teaching of the digging preparation position, interference avoidance position, and loading position of the bucket 133 from the operator as reference points for automatic control. Teaching is performed, for example, according to the following procedure. The reference identification unit 616 displays an instruction to move the bucket 133 to the digging preparation position on the operation terminal 142. The operator operates the operation device 143 to move the bucket 133 to the digging preparation position and presses the teaching switch 143TS. The reference identification unit 616 sets the attitude of the work implement 130 identified by the work implement position identification unit 615 when the teaching switch 143TS is pressed as the target attitude for the second swing, sets the position of the tip P of the arm 132 as the target position for the second swing, and records the orientation of the rotating body 120 as the target orientation for the second swing in the storage 650. Next, the reference identification unit 616 displays on the operation terminal 142 an instruction to move the cutting edge of the bucket 133 to an interference avoidance position that is at the same height as the upper end of the vessel wall of the loading target T and where the work implement 130 and the loading target T do not overlap in a plan view from above. The vessel wall used for teaching may be any of the side, front, or rear walls of the vessel. The operator operates the operation device 143 to move the cutting edge of the bucket 133 to the interference avoidance position and presses the teaching switch 143TS. The interference avoidance positions are input for both the right and left ends of the loading target T. This allows the reference identification unit 616 to identify the range of the loading platform of the loading target T. The height of the interference avoidance position may be offset upward to allow for control errors and measurement errors. The reference identification unit 616 determines the height of the lowest point Q of the bucket 133 determined by the work machine position identification unit 615 when the teaching switch 143TS is pressed as the wall height Ht of the loading target T, and records the orientation of the rotating unit 120 as the interference avoidance orientation in the storage 650. The wall height Ht is an example of the height of the loading target T. Next, the reference identification unit 616 causes the operation terminal 142 to display an instruction to move the bucket 133 to a loading position above the loading target T. The operator operates the operation device 143 to move the bucket 133 to the loading position and presses the teaching switch 143TS.The reference identification unit 616 sets the attitude of the work machine 130 when the teaching switch 143TS is pressed as the target attitude for the first swing, the position of the tip P of the arm 132 as the target position for the first swing, and the orientation of the rotating body 120 identified by the work machine position identification unit 615 as the target orientation for the first swing, and records these in the storage 650. The height of the lowest point Q of the bucket 133 identified at the loading position may also be set as the wall height Ht. In other embodiments, the height of the loading target T does not necessarily have to be the wall height Ht, which is the height of the side wall of the loading platform, but may be the height of the highest point of the entire loading target T.

[0042] The angle identification unit 617 identifies, as a target swing angle, the angle between the initial orientation to which the swing unit 120 faces when an automatic control instruction signal is input to the operation signal input unit 614 and the target orientation recorded in the storage 650. The angle identification unit 617 identifies, as an interference avoidance angle, the angle between the initial orientation to which the swing unit 120 faces when an automatic control instruction signal is input to the operation signal input unit 614 and the interference avoidance orientation recorded in the storage 650. The interference avoidance angle is the swing angle at which the work machine 130 and the loading target T do not overlap in a plan view from above.

[0043] The movement control unit 618 generates an automatic operation signal that realizes automatic control when the operation signal input unit 614 receives an input of an automatic control instruction signal. When the automatic control instruction signal is input, the movement control unit 618 executes automatic control that realizes a first swing that moves the bucket 133 to a loading position, or automatic control that realizes a second swing that moves the bucket 133 to an excavation preparation position. The movement control unit 618 determines whether to execute the first swing or the second swing in the automatic control based on whether the bucket 133 is within the range of the loading target T in a plan view from above when the automatic control instruction signal is input. If the bucket 133 is not within the range of the loading target T's bed, the movement control unit 618 executes the first swing, and if the bucket 133 is within the range of the loading target T's bed, the movement control unit 618 executes the second swing. At this time, the movement control unit 618 controls the revolving unit 120 and the work implement 130 so that the loading target T and the work implement 130 do not come into contact with each other, based on the wall height Ht and the interference avoidance angle stored in the storage 650.

[0044] Specifically, during the first swing, the movement control unit 618 realizes combined operation of the rotating unit 120 and the work implement 130 by the time the swing angle of the rotating unit 120 reaches the first interference avoidance angle θ1 ( FIG. 4 ). During the first swing, if the height of the bucket 133 does not reach the height of the loading position by the time the swing angle of the rotating unit 120 reaches the first interference avoidance angle θ1 ( FIG. 4 ), the movement control unit 618 does not generate a swing operation signal for the rotating unit 120, but generates only an operation signal for the work implement 130. On the other hand, if the height of the bucket 133 reaches the height of the loading position by the time the swing angle due to the swing reaches the first interference avoidance angle θ1, the movement control unit 618 generates a swing operation signal for the rotating unit 120 and an operation signal for the work implement 130, thereby realizing combined operation of the rotating unit 120 and the work implement 130. After the height of the bucket 133 reaches the height of the loading position at the first interference avoidance angle θ1 ( FIG. 4 ), the movement control unit 618 swings the rotating unit 120 without moving the work implement 130. Furthermore, during a second swing that rotates in the opposite direction to the first swing, the movement control unit 618 controls the lowest point of the bucket 133 not to lower until the swing angle of the rotating unit 120 reaches a second interference avoidance angle θ2 ( FIG. 5 ). The control to prevent the lowest point from lowering may involve rotating the rotating unit 120 without moving the work implement 130, maintaining the height of the lowest point, or may involve raising the lowest point higher than the lowest point before the control, thereby creating a gap between the loading target T and the bucket 133. After the swing angle reaches the second interference avoidance angle θ2, the movement control unit 618 generates a swing operation signal for the rotating unit 120 and an operation signal for the work implement 130, thereby realizing combined operation of the rotating unit 120 and the work implement 130. However, when the movement control unit 618 receives input of an automatic control instruction signal during the second rotation, if the height of the lowest point of the bucket 133 is lower than the wall height Ht of the loading object T, the movement control unit 618 moves the bucket 133 upward before rotating the rotating body 120.

[0045] The operation signal output unit 619 outputs the manual operation signal input to the operation signal input unit 614 or the automatic operation signal generated by the movement control unit 618 to the control valve 123 .

[0046] <<Operation During Automatic Control>> Here, the movement of the work machine 100 during automatic control according to the first embodiment will be described with reference to the drawings. Figure 4 is a diagram showing an example of the movement of the work machine 100 during a first swing according to the first embodiment. Figure 5 is a diagram showing an example of the movement of the work machine 100 during a second swing according to the first embodiment.

[0047] When automatic control for the first swing is initiated, as shown in FIG. 4 , the control device 160 first starts driving the work implement 130 (boom 131, arm 132, and bucket 133) and raises the boom 131 to move the bucket 133 upward. The target position of the bucket 133 for the first swing is a loading position above the loading target T. After a delay, the control device 160 starts swinging the rotating unit 120. The control device 160 adjusts the swing start timing using the following procedure. The control device 160 calculates the remaining amount of movement of the work implement 130 based on the target attitude of the work implement 130 and the attitude of the work implement 130 at the current time. By adjusting the amount of swing operation based on the remaining amount of movement of the work implement 130, the control device 160 controls the swing so that the work implement 130 reaches the target attitude by the time the swing angle of the swing unit 120 reaches the first interference avoidance angle θ1. If the attitude of the work implement 130 reaches the target attitude for the first swing by the time the swing angle of the swing unit 120 matches the first interference avoidance angle θ1, that is, if the height of the lowest point Q of the bucket 133 is higher than the wall height Ht of the object to be loaded T, the swing of the swing unit 120 will not cause the work implement 130 to come into contact with the object to be loaded T. If the work implement 130 is driven simultaneously with the swing, and the attitude of the work implement 130 reaches the target attitude for the first swing by the time the swing angle matches the first interference avoidance angle θ1, the control device 160 may start driving and swinging the work implement 130 simultaneously. Thereafter, when the bucket 133 reaches the loading position, the automatic control ends.

[0048] The operator then manually performs a dump operation by rotating the bucket 133 in the dump direction. During a manual dump operation, the operator may load the load at a low position to reduce the impact on the object T to be loaded. The operator may also operate the work machine 100 to level the load loaded on a bed such as a vessel. At this time, the lowest point Q of the bucket 133 may be lower than the wall of the object T to be loaded. Therefore, if the control device 160 continues to swing the work machine 100 in this state, the bucket 133 will come into contact with the inner wall of the object T to be loaded.

[0049] When automatic control for the second swing is initiated, the control device 160 determines whether the lowest point of the bucket 133 is higher than the wall of the loading target T. As shown in FIG. 5 , if the lowest point Q of the bucket 133 is lower than the wall height Ht, the control device 160 raises the boom 131. When the lowest point Q of the bucket 133 becomes higher than the wall height Ht, the control device 160 starts swinging the rotating unit 120. The control device 160 swings the rotating unit 120 without moving the work implement 130, and maintains the height of the lowest point of the bucket 133, until the swing angle of the rotating unit 120 exceeds the second interference avoidance angle θ2. Note that in the first embodiment, when the lowest point Q of the bucket 133 is lower than the wall height Ht, the control device 160 raises only the work implement 130 and does not swing the rotating unit 120, but this is not limited to this in other embodiments. For example, in another embodiment, when the lowest point Q of the bucket 133 is lower than the wall height Ht, the control device 160 may raise the work machine 130 while rotating the rotating body 120 at a speed that prevents the bucket 133 from contacting the wall of the loading object T.

[0050] When the swing angle of the rotating unit 120 exceeds the second interference avoidance angle θ2, the control device 160 drives the boom 131, the arm 132, and the bucket 133. At this time, the control device 160 may drive all of the boom 131, the arm 132, and the bucket 133, or may drive only a portion of the boom 131, the arm 132, and the bucket 133, depending on the relationship between the attitude at the start of swing and the target attitude. When the swing angle of the rotating unit 120 reaches the target swing angle θ0, the control device 160 stops driving the rotating unit 120. Furthermore, when the attitude of the work implement 130 reaches the target attitude at the start of excavation, the control device 160 stops driving the work implement 130. The control device 160 according to the first embodiment swings the rotating unit 120 without moving the work implement 130 during the second swing until the swing angle of the rotating unit 120 exceeds the second interference avoidance angle θ2, but this is not limited to this. For example, the control device 160 according to another embodiment may rotate the revolving unit 120 while moving the work implement 130 so that the height of the lowest point of the bucket 133 does not change. Furthermore, when the bucket 133 is higher than the wall height Ht, the control device 160 according to an embodiment may rotate the revolving unit 120 while lowering the work implement 130 to an extent that the height of the lowest point of the bucket 133 does not fall below the wall height Ht. While FIGS. 4 and 5 show an example in which the positional relationship between the excavation position and the object to be loaded T is approximately 90 degrees around the revolving unit 120, this is not limited to this in other embodiments. For example, in other embodiments, the positional relationship between the excavation position and the object to be loaded T may be another rotation angle position, such as approximately 180 degrees around the revolving unit 120.

[0051] <<Operation of Control Device 160>> Figure 6 is a flowchart showing the data collection process by the control device 160 according to the first embodiment. The control device 160 collects data used to control the work machine 100 at predetermined collection intervals. First, the measurement data acquisition unit 611 of the control device 160 acquires various measurement data from the measurement system (step S1). The orientation accuracy determination unit 612 determines whether the analysis results of the horizontal position and height indicated by the GNSS measurement data acquired in step S1 are fix solutions (step S2). If both the analysis results of the horizontal position and height are fix solutions (step S2: YES), the orientation accuracy determination unit 612 determines whether the two antennas provided in the position and orientation calculator 151 are receiving signals from a predetermined number or more of common satellites (step S3). If the two antennas are receiving signals from a predetermined number of common satellites or more (step S3: YES), the orientation accuracy determination unit 612 determines that the accuracy of the GNSS measurement data is sufficient for automatic control, and decides to use the GNSS measurement data as orientation data for the rotating unit 120 (step S4). The orientation accuracy determination unit 612 resets a timer that measures the elapsed time from the time when the orientation accuracy indicated by the GNSS measurement data became insufficient (step S5).

[0052] On the other hand, if the analysis result of either the horizontal position or the height is not a fixed solution (step S2: NO), or if the number of common satellites whose signals are received by the two antennas of the position and orientation calculator 151 is less than a predetermined number (step S3: NO), the orientation accuracy determination unit 612 counts up a timer that measures the elapsed time from the time when the orientation accuracy indicated by the GNSS measurement data became insufficient (step S6).

[0053] The orientation accuracy determination unit 612 determines whether the elapsed time since the orientation accuracy indicated by the GNSS measurement data became insufficient exceeds a predetermined time (step S7). If the elapsed time does not exceed the predetermined time (step S7: NO), the alternative orientation calculation unit 613 calculates alternative orientation data based on the GNSS measurement data for which the GNSS accuracy was last determined to be sufficient and the yaw angular velocity measurement data from the time when the GNSS accuracy was last determined to be sufficient to the current time (step S8). Note that the alternative orientation calculation unit 613 may calculate the alternative orientation data by adding a turning angle calculated from the yaw angular velocity measurement data acquired in step S1 to the previous orientation data (GNSS measurement data or alternative orientation data). The alternative orientation calculation unit 613 may calculate the alternative orientation data by adding a turning angle calculated from the yaw angular velocity from the start time of automatic control to the GNSS measurement data that is determined to have sufficient accuracy at the time the start switch 143SW is pressed, i.e., at the start of automatic control. The orientation accuracy determination unit 612 determines that the accuracy of the alternative orientation data is sufficient for automatic control, and decides to use the alternative orientation data as the orientation data of the rotating unit 120 (step S9).

[0054] On the other hand, if the elapsed time since the last time the GNSS accuracy was determined to be sufficient exceeds a predetermined time (step S7: YES), the direction accuracy determination unit 612 determines that the accuracy of the alternative direction data is insufficient for automatic control (step S10).

[0055] 7 is a flowchart showing automatic control by the control device 160 according to the first embodiment. When the operator presses the start switch 143SW, the operation signal input unit 614 of the control device 160 receives an input of an automatic control instruction signal. When the automatic loading instruction signal is received, the control device 160 determines whether to perform a first rotation or a second rotation based on whether the bucket 133 is within a range above the loading platform of the loading target T in a plan view from above. When performing a first rotation, the control device 160 performs automatic control based on the first interference avoidance angle θ1 and the target rotation angle θ0. When performing a second rotation, the control device 160 performs automatic control based on the second interference avoidance angle θ2 and the target rotation angle θ0.

[0056] The control device 160 executes the data collection process shown in Fig. 6 (step S51). The control device 160 determines whether the accuracy of the orientation data is insufficient for automatic control (step S52). If it is determined in step S10 of the data collection process that the accuracy of the orientation data is insufficient for automatic control (step S52: YES), the control device 160 ends the process without starting automatic control. At this time, the control device 160 may display on the operation terminal 142 that automatic control is not possible due to low accuracy of GNSS positioning. For example, the control device 160 may display on the operation terminal 142 "GNSS positioning initializing."

[0057] If the accuracy of the orientation data is sufficient (step S52: NO), the angle identification unit 617 identifies a target turning angle and an interference avoidance angle based on the orientation data (GNSS measurement data or alternative orientation data) and the target orientation and interference avoidance orientation recorded in the storage 650 (step S53). The angle identification unit 617 records the orientation data determined in step S51 as the initial orientation.

[0058] Thereafter, the movement control unit 618 generates an automatic operation signal for moving the bucket 133 to above the loading target T. Specifically, the movement control unit 618 generates the automatic operation signal in the following procedure.

[0059] First, the work implement position identification unit 615 identifies the position of the tip P of the arm 132, the position of the lowest point Q of the bucket 133, and the attitude of the bucket 133 based on the measurement data (step S54). The movement control unit 618 determines whether the position of the tip of the arm 132 is close to the target position (loading position or excavation position) related to teaching (step S55). That is, the movement control unit 618 determines whether the attitude of the work implement 130 is close to the target attitude and whether the swing angle of the revolving unit 120 is close to the target swing angle. For example, the movement control unit 618 determines that the attitude of the work implement 130 is close to the target attitude when the difference between the position of the tip of the arm 132 in the target attitude and the current position of the tip of the arm 132 is equal to or less than a predetermined value. The movement control unit 618 according to the first embodiment identifies the swing angle based on the difference between the orientation indicated by the GNSS measurement data or alternative orientation data and the initial orientation.

[0060] If the tip of the arm 132 is not close to the target position (step S55: NO), the movement control unit 618 generates an automatic operation signal (step S56) and outputs the automatic operation signal to the control valve 123 (step S57).

[0061] Next, the control device 160 executes the data collection process shown in FIG. 6 (step S58). The control device 160 determines whether the accuracy of the orientation data is insufficient for automatic control (step S59). If it is determined in step S7 of the data collection process that the accuracy of the GNSS measurement data or alternative orientation data is sufficient for automatic control (step S59: NO), the control device 160 returns the process to step S54 and continues automatic control. On the other hand, if it is determined in step S7 of the data collection process that the accuracy of the orientation data is insufficient for automatic control (step S59: YES), the control device 160 cancels automatic control and ends the process. At this time, the control device 160 may display on the operation terminal 142 that automatic control is not possible due to low accuracy of GNSS positioning. For example, the control device 160 may display "GNSS positioning initialization" on the operation terminal 142.

[0062] On the other hand, in step S55, if the position of the tip of the arm 132 is close to the target position related to teaching (step S55: YES), the control device 160 ends the rotation process.

[0063] <<Actions and Effects>> As described above, the work machine 100 according to the first embodiment has the following configuration. The work machine 100 includes a main body that includes a running body 110 and a swinging body 120 that swings relative to the running body 110. The work machine 100 includes a swing motor 124 that drives the swinging body 120 to swing relative to the running body 110. The work machine 100 includes a position and orientation calculator 151 provided on the main body that acquires first measurement data, which is GNSS measurement data. The work machine 100 includes a control device 160 that executes swing control using the swing motor 124 based on the first measurement data. The control device 160 determines whether to start swing control based on the accuracy of the first measurement data. As a result, the work machine 100 decides not to start swing control when the accuracy of the GNSS measurement data becomes insufficient for swing control. Therefore, the work machine 100 can prevent unintended behavior caused by inaccuracies in the GNSS measurement data.

[0064] Furthermore, the control device 160 according to the first embodiment determines whether to continue swing control based on the first measurement data acquired during swing control. In other words, the work machine 100 stops swing control if the accuracy of the GNSS measurement data becomes insufficient during swing control. Therefore, the work machine 100 can prevent unintended behavior caused by inaccuracies in the GNSS measurement data.

[0065] Furthermore, the control device 160 according to the first embodiment suspends the turning control when a predetermined time has elapsed since the accuracy of the first measurement data no longer satisfies the conditions for the turning control, thereby preventing the control device 160 from frequently suspending the turning control due to a short-term decrease in accuracy of the first measurement data.

[0066] The work machine 100 according to the first embodiment is also equipped with an inclinometer 152 that acquires second measurement data, which is measurement data relating to the swing angle of the running body 110 and the swing body 120. The yaw angular velocity measured by the inclinometer 152 can be integrated to obtain the swing angle. The control device 160 according to the first embodiment executes swing control based on the second measurement data until a predetermined time has elapsed from the point in time when the accuracy of the first measurement data no longer satisfies the conditions for swing control. This allows the control device 160 to prevent swing control from becoming impossible when the accuracy of the first measurement data decreases.

[0067] Second Embodiment The alternative orientation calculation unit 613 according to the first embodiment calculates alternative orientation data based on the GNSS measurement data last determined to have sufficient GNSS accuracy and the yaw angular velocity measurement data from the time last determined to have sufficient GNSS accuracy to the current time. Meanwhile, integrating the yaw angular velocity measurement data amplifies errors contained in the yaw angular velocity measurement data, gradually reducing the accuracy of the alternative orientation data. In contrast, the alternative orientation calculation unit 613 according to the second embodiment can calculate alternative orientation data that minimizes the effects of errors by using a Kalman filter.

[0068] The alternative orientation calculation unit 613 according to the second embodiment has a Kalman filter that calculates the position, orientation, and inclination angle of the work machine 100. The alternative orientation calculation unit 613 estimates the current position, orientation, and inclination angle of the work machine 100 based on the previous estimation result and current measurement data.

[0069] The alternative orientation calculation unit 613 according to the second embodiment estimates the position, orientation, and inclination angle at time t using the estimation results of the position, orientation, and inclination angle at time t-1 as the "state (posterior belief)," the angular velocity of the work machine 100 at time t indicated by the measurement data of the inclination measuring device 152 as the "control value," and the position and orientation at time t indicated by the measurement data of the position / orientation calculator 151 and the inclination angle at time t indicated by the measurement data of the inclination measuring device 152 as the "observation value." Note that the alternative orientation calculation unit 613 may estimate the position, orientation, and inclination angle using a Kalman gain based on a variance-covariance matrix that indicates the uncertainty of the estimation result.

[0070] In this way, the control device 160 according to the second embodiment can calculate the alternative direction data with high accuracy by using the Kalman filter.

[0071] The control device 160 according to the second embodiment determines that the accuracy of the alternative orientation data is insufficient and suspends the automatic control after a predetermined time has elapsed since the accuracy of the GNSS measurement data became insufficient for the automatic control during the automatic control, as in the first embodiment, but is not limited to this. For example, in other embodiments, if the accuracy of the orientation estimated by the alternative orientation calculation unit 613 is sufficiently high, the control device 160 may continue the automatic control based on the alternative orientation data without suspending the automatic control.

[0072] Third Embodiment The work machine 100 according to the first and second embodiments sets a reference point for automatic control by teaching, whereas the work machine 100 according to the third embodiment sets a reference point for automatic control without teaching.

[0073] 8 is a schematic diagram showing the configuration of a work machine 100 according to the third embodiment. The work machine 100 according to the third embodiment further includes a rotary encoder 156 as a measurement system. The rotary encoder 156 is provided at the center of rotation of the running body 110 and the revolving body 120, and outputs measurement data that indicates the rotation angle of the revolving body 120 relative to the running body 110.

[0074] FIG. 9 is a schematic block diagram showing the configuration of a control device 160 according to the third embodiment. The control device 160 according to the third embodiment further includes a position receiving unit 620 in addition to the configuration of the first embodiment. The position receiving unit 620 receives GNSS measurement data of the loading object T through communication. That is, the loading object T according to the third embodiment includes a GNSS positioning device and a communication device, and is configured to be able to transmit GNSS measurement data. The position receiving unit 620 may receive the measurement data directly from the loading object T, or may receive the measurement data from a control system that remotely controls the loading object T. The positioning device included in the loading object T is an example of a positioning sensor provided on the loading object T.

[0075] The reference identification unit 616 according to the third embodiment identifies an interference avoidance position and a loading position based on GNSS measurement data of the loading object T. For example, when an automatic control instruction signal is input, the reference identification unit 616 identifies the loading position based on the position and orientation of the loading object T indicated by the GNSS measurement data of the loading object T received by the position receiving unit 620, as well as the known shape of the loading object T. The reference identification unit 616 identifies a planar position of the vessel of the loading object T based on the position and orientation of the loading object T. The reference identification unit 616 identifies, from the planar position, a position that is a predetermined distance from the height of the loading object T identified from the known shape of the loading object T, as the loading position.

[0076] Based on the position and orientation of the loading object T and the known shape of the loading object T, the reference identification unit 616 identifies, as the interference avoidance position, the position on a circle centered on the rotation center of the rotating body 120 and with a radius equal to the distance between the rotation center and the unloading position, where the outer shape of the bucket 133 does not interfere with the loading object T in a planar view and is closest to the loading position.

[0077] <<Operation of control device 160>> Figure 10 is a flowchart showing the data collection process by the control device 160 according to the third embodiment. The control device 160 collects data used to control the work machine 100 at predetermined collection intervals. First, the measurement data acquisition unit 611 of the control device 160 acquires various measurement data from the measurement system (step S101). Furthermore, the position receiving unit 620 receives GNSS measurement data from the loading object T (step S102).

[0078] The orientation accuracy determination unit 612 determines whether the analysis results of the horizontal position and height of the work machine 100 indicated by the GNSS measurement data acquired in step S101 are fix solutions (step S103). If the analysis results of the horizontal position and height of the work machine 100 are both fix solutions (step S103: YES), the orientation accuracy determination unit 612 determines whether the two antennas provided in the position and orientation calculator 151 are receiving signals from a predetermined number or more of common satellites (step S104).

[0079] If the two antennas are receiving signals from a predetermined number or more of common satellites (step S104: YES), that is, if the accuracy of the GNSS measurement data of the work machine 100 is sufficient, the orientation accuracy determination unit 612 determines whether or not the analysis results of the horizontal position and height of the loading object T indicated by the GNSS measurement data of the loading object T received in step S102 are fixed solutions (step S105). If the analysis results of the horizontal position and height of the work machine 100 are both fixed solutions (step S105: YES), the orientation accuracy determination unit 612 determines whether or not the two antennas equipped on the loading object T are receiving signals from a predetermined number or more of common satellites (step S106). If the two antennas of the loading object T are receiving signals from a predetermined number or more of common satellites (step S106: YES), that is, if the accuracy of the GNSS measurement data of both the work machine 100 and the loading object T is sufficient, the azimuth accuracy determination unit 612 determines that the accuracy of the GNSS measurement data is sufficient for automatic control (step S107).

[0080] On the other hand, if the analysis result of either the horizontal position or height of the work machine 100 or the loading object T is not a fix solution (step S103 or S105: NO), or if the number of common satellites from which signals are received by the two antennas of the position and orientation calculator 151 or the loading object T is less than a predetermined number (step S104 or S106: NO), the orientation accuracy determination unit 612 determines that the accuracy of the alternative orientation data is insufficient for automatic control (step S108). More specifically, if any of the analysis results of the horizontal position of the measurement data related to the first antenna of the position and orientation calculator 151, the analysis result of the height of the measurement data related to the first antenna, the analysis result of the horizontal position of the measurement data related to the second antenna, and the analysis result of the height of the measurement data related to the second antenna are not a fix solution, the orientation accuracy determination unit 612 determines that the accuracy of the alternative orientation data is insufficient for automatic control.

[0081] FIG. 11 is a flowchart illustrating automatic control by the control device 160 according to the third embodiment. When the operator presses the start switch 143SW, the operation signal input unit 614 of the control device 160 receives an input of an automatic control instruction signal. First, the control device 160 executes the data collection process shown in FIG. 10 (step S151). The control device 160 determines whether the accuracy of the orientation data is insufficient for automatic control (step S152). If it is determined in step S108 of the data collection process that the accuracy of the orientation data is insufficient for automatic control (step S152: YES), the control device 160 terminates the process without starting automatic control. At this time, the control device 160 may display on the operation terminal 142 that automatic control is not possible due to low accuracy of GNSS positioning. For example, the control device 160 may display "GNSS positioning initialization" on the operation terminal 142.

[0082] If the accuracy of the orientation data is not insufficient (step S152: NO), the reference specifying unit 616 specifies the reference positions for automatic control (loading position, interference avoidance position, excavation position) based on the GNSS measurement data of the loading object T (step S153). Next, the angle specifying unit 617 specifies the target turning angle and interference avoidance angle based on the reference positions for automatic control and the GNSS measurement data acquired by the position and orientation calculator 151 (step S154).

[0083] Thereafter, the movement control unit 618 generates an automatic operation signal for moving the bucket 133 to above the loading target T. Specifically, the movement control unit 618 generates the automatic operation signal in the following procedure.

[0084] First, the work implement position identifying unit 615 identifies the position of the tip P of the arm 132, the position of the lowest point Q of the bucket 133, and the attitude of the bucket 133 based on the measurement data (step S155). The movement control unit 618 determines whether the position of the tip of the arm 132 is close to the target position related to teaching (step S156). That is, the movement control unit 618 determines whether the attitude of the work implement 130 is close to the target attitude and whether the swing angle of the revolving unit 120 is close to the target swing angle. For example, the movement control unit 618 determines that the attitude of the work implement 130 is close to the target attitude when the difference between the position of the tip of the arm 132 in the target attitude and the current position of the tip of the arm 132 is equal to or less than a predetermined value. The movement control unit 618 according to the third embodiment identifies the swing angle based on the measurement data of the rotary encoder 156.

[0085] If the tip of the arm 132 is not close to the target position (step S156: NO), the movement control unit 618 generates an automatic operation signal (step S157) and outputs the automatic operation signal to the control valve 123 (step S158).

[0086] Next, the measurement data acquisition unit 611 acquires measurement data from the measurement system (step S159). The control device 160 according to the third embodiment determines the turning angle based on the measurement data of the rotary encoder 156, and therefore, unlike the inclinometer 152, no error accumulates in the turning angle. The control device 160 may also determine the turning angle by integrating the yaw angular velocity from the time the start switch 143SW is pressed to the current time. In this case, too, the error in the turning angle is reset when automatic control begins, so the error accumulated in the turning angle is small. Therefore, the control device 160 according to the third embodiment does not need to stop automatic control even if the accuracy of the GNSS measurement data decreases during automatic control.

[0087] In step S156, if the position of the tip of the arm 132 is close to the target position (step S156: YES), the control device 160 ends the rotation process.

[0088] <Other Embodiments> One embodiment has been described in detail above with reference to the drawings, but the specific configuration is not limited to that described above, and various design changes and the like are possible. That is, in other embodiments, the order of the above-described processes may be changed as appropriate. Furthermore, some of the processes may be executed in parallel. The control device 160 according to the above-described embodiment may be configured by a single computer, or the configuration of the control device 160 may be divided among multiple computers, and the multiple computers may function as the control device 160 by cooperating with each other. In this case, some of the computers that make up the control device 160 may be mounted inside the work machine 100, and other computers may be provided external to the work machine 100. For example, the work machine 100 may be operated by remote control, in which case the computers that make up the control device 160 may be divided among the work machine 100, the remote control device, and the control server.

[0089] The work machine 100 according to the first and second embodiments calculates alternative orientation data based on measurement data from the inclinometer 152, and the work machine 100 according to the third embodiment determines the turning angle based on measurement data from the rotary encoder 156, but this is not limited to this. For example, the control device 160 according to other embodiments may calculate the orientation or turning angle based on processing of image data captured by an imaging device provided on the work machine 100 (for example, SLAM processing using point cloud data from LIDAR) or measurement data from a geomagnetic sensor.

[0090] Furthermore, although the work machine 100 according to the embodiment described above is a hydraulic excavator in which the rotating unit 120 rotates relative to the traveling unit 110, the present invention is not limited to this. For example, the work machine 100 according to other embodiments may be a work vehicle such as a wheel loader or dump truck having an articulation mechanism. The main body of a work vehicle having an articulation mechanism is divided into a front section and a rear section, and the front section is driven to rotate relative to the rear section. Furthermore, the work machine 100 according to other embodiments may be fixed to the ground and not travel. Furthermore, if the work implement 130 of the work machine 100 according to other embodiments has a rotatable configuration such as an offset boom or tiltrotator, the control device 160 may determine whether or not to control the rotation of the work implement 130. In this case, the rotatable work implement 130 is an example of a second main body, and the vehicle body to which the work implement 130 is attached is an example of a first main body.

[0091] The control device 160 according to the first and second embodiments continues automatic control using alternative orientation data calculated from other measurement data when the accuracy of the GNSS measurement data becomes insufficient during automatic control, but is not limited to this. For example, the control device 160 according to other embodiments may continue automatic control by estimating the turning angle based on the turning speed calculated from the change in orientation until the accuracy of the GNSS measurement data becomes insufficient.

[0092] The control device 160 according to the first and second embodiments suspends and terminates the automatic control when the accuracy of the GNSS measurement data and the alternative orientation data becomes insufficient during the automatic control, but is not limited to this. For example, the control device 160 according to other embodiments may suspend the automatic control when the accuracy of the GNSS measurement data and the alternative orientation data becomes insufficient during the automatic control, and automatically resume the automatic control when the accuracy of the GNSS measurement data becomes sufficient again for the automatic control.

[0093] According to the present disclosure, as one example, it is possible to prevent unintended behavior caused by the accuracy of measurement data.

[0094] DESCRIPTION OF SYMBOLS 100...Work machine 110...Traveling body 111...Crawler 112...Travel motor 120...Swinging body 121...Engine 122...Hydraulic pump 123...Control valve 124...Swing motor 130...Working machine 131...Boom 131C...Boom cylinder 132...Arm 132C...Arm cylinder 133...Bucket 133C...Bucket cylinder 140...Driver's cab 141...Driver's seat 142...Operation terminal 143...Operation device 151...Position and orientation calculator 152...Inclination measuring device 153...Boom stroke sensor 154...Arm stroke sensor 155...Bucket stroke sensor 156...Rotary encoder 160...Control device 610...Processor 611...Measurement data acquisition unit 612...Orientation accuracy determination unit 613...Alternative orientation calculation unit 614...Operation signal input unit 615: Work machine position identification unit 616: Reference identification unit 617: Angle identification unit 618: Movement control unit 619: Operation signal output unit 620: Position receiving unit 630: Main memory 650: Storage 670: Interface T: Loading target

Claims

1. A work machine comprising: a main body having a first body and a second body that rotates relative to the first body; an actuator that drives the second body to rotate relative to the first body; a first sensor provided on the main body that obtains first measurement data which is positioning data; and a controller that executes rotation control by the actuator based on the first measurement data, and that determines whether or not to execute the rotation control based on the accuracy of the first measurement data.

2. A work machine according to claim 1, wherein the controller determines whether or not to continue the swing control based on the first measurement data acquired during the swing control.

3. A work machine as described in claim 2, wherein the controller discontinues the swing control when a predetermined time has elapsed since the accuracy of the first measurement data no longer satisfies the condition related to the swing control.

4. A work machine as described in claim 3, further comprising a second sensor for acquiring second measurement data which is measurement data relating to a rotation angle between the first body and the second body, and the controller executes the rotation control based on the second measurement data until the specified time has elapsed from the point in time when the accuracy of the first measurement data no longer satisfies the condition relating to the rotation control.

5. A work machine as set forth in claim 1, wherein said first measurement data includes data indicative of a position of said first sensor relative to a satellite.

6. The work machine according to claim 5, wherein the controller permits the start of the turning control when the position indicated by the first measurement data is a Fix solution.

7. A work machine as described in claim 1, further comprising: an acquisition unit that acquires third measurement data, which is measurement data from a positioning sensor provided on the loading target; and the controller that determines a target rotation angle for the rotation control based on the first measurement data and the third measurement data, and determines whether or not to start the rotation control based on the accuracy of the first measurement data and the accuracy of the third measurement data.

8. A control method for a work machine comprising: a main body having a first body and a second body that rotates relative to the first body; an actuator that drives the second body to rotate relative to the first body; a first sensor provided on the main body that obtains first measurement data which is positioning data; and a controller, the control method having the steps of: the controller determining whether or not rotation control can be performed by the actuator based on accuracy of the first measurement data; and the controller executing the rotation control based on the first measurement data when start of the rotation control is permitted.

9. A work system comprising: a main body having a first body and a second body that rotates relative to the first body; an actuator that drives the second body to rotate relative to the first body; a first sensor provided on the main body that obtains first measurement data which is positioning data; and a controller that executes rotation control by the actuator based on the first measurement data, and determines whether or not to execute the rotation control based on the accuracy of the first measurement data.

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