CONTROL DEVICE FOR WORK MACHINE, REMOTE OPERATION SYSTEM, AND CONTROL METHOD

Abstract

A control device for a work machine including a revolving body configured to revolve about a revolution center, a support part configured to support the revolving body, and a work implement that is attached to the revolving body and includes a work tool, includes a remainder estimation unit configured to estimate whether a load is remaining in the work tool, and an output unit configured to provide an output based on a result of the estimation on whether the load is remaining in the work tool.

Description

TECHNICAL FIELD

The present disclosure relates to a control device for a work machine, a remote operation system, and a control method.

The present disclosure claims priority based on Japanese Patent Application No. 2023-042036, filed Mar. 16, 2023, the content of which is incorporated herein by reference.

BACKGROUND ART

Patent Disclosure 1 discloses a technique related to semi-automatic control of a work machine. The semi-automatic control according to Patent Disclosure 1 is control for automatically moving a bucket to an excavation position when an excavation instruction is received from an operator after loading on a loading target, such as a dump truck, has been completed, and causing a control device to control revolution of the work machine and driving of a work implement.

CITATION LIST

Patent Literature

Patent Document 1: JP 2020-041352 A

SUMMARY OF INVENTION

Technical Problem

However, the operator may start the automatic revolution control while the load is still remaining on the work tool such as the bucket.

An object of the present disclosure is to provide a control device and a control method for a work machine enabling determination on whether a load has been completely unloaded from a work tool in a loading work.

Solution to Problem

According to an aspect of the present disclosure, a control device for a work machine including a revolving body configured to revolve about a revolution center, a support part configured to support the revolving body, and a work implement that is attached to the revolving body and includes a work tool, includes a remainder estimation unit configured to estimate whether a load is remaining in the work tool, and an output unit configured to provide an output based on a result of the estimation on whether the load is remaining in the work tool.

Advantageous Effects of Invention

According to the above aspect, the control device for a work machine enables determination on whether the load has been completely unloaded from the work tool in a loading work.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view illustrating a configuration of a loading machine according to a first embodiment.

FIG. 2 is a view illustrating an internal configuration of a cab according to the first embodiment.

FIG. 3 is a schematic block diagram illustrating a configuration of a control device according to the first embodiment.

FIG. 4 is a view illustrating an example of movement of the loading machine in a first revolution according to the first embodiment.

FIG. 5 is a view illustrating an example of movement of the loading machine in a second revolution according to the first embodiment.

FIG. 6 is a flowchart illustrating first revolution control by the control device according to the first embodiment.

FIG. 7 is a flowchart illustrating second revolution control by the control device according to the first embodiment.

DESCRIPTION OF EMBODIMENTS

First Embodiment

Hereinafter, embodiments will be described in detail with reference to the drawings.

Configuration of Loading Machine 100

FIG. 1 is a schematic view illustrating a configuration of a loading machine 100 according to a first embodiment.

The loading machine 100 operates at a construction site, excavates a construction target such as earth and sand, and loads the excavated earth and sand as a load onto a loading target T (FIG. 4 and FIG. 5) such as a dump truck. The loading machine 100 is an example of a work machine. Examples of the loading machine 100 include a face shovel, a backhoe shovel, a rope shovel, and the like. Further, the loading machine 100 may be electrically driven or may be hydraulically driven. The loading machine 100 according to the first embodiment is a backhoe shovel. The loading machine 100 includes a traveling body 110, a revolving body 120, a work implement 130, and a cab 140. Examples of the loading target T include a dump truck, a hopper, and the like.

The traveling body 110 supports the loading machine 100 in a manner that enables travel. The traveling body 110 includes two endless tracks 111 provided on left and right sides and two travel motors 112 for driving the endless tracks 111. The traveling body 110 is an example of a support part.

The revolving body 120 is supported by the traveling body 110 so as to be revolvable about a revolution center.

The work implement 130 is driven by hydraulic pressure. The work implement 130 is supported at a front portion of the revolving body 120 so as to be drivable in a vertical direction.

The cab 140 is a space where an operator rides and operates the loading machine 100. The cab 140 is provided in a left front portion of the revolving body 120.

Here, a portion of the revolving body 120 where the work implement 130 is attached is referred to as a front portion. Further, in the revolving body 120, with reference to the front portion, a portion on a side opposite thereto is referred to as a rear portion, a portion on the left side is referred to as a left portion, and a portion on the right side is referred to as a right portion.

Configuration of Revolving Body 120

The revolving body 120 includes an engine 121, a hydraulic pump 122, a control valve 123, and a revolution 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 actuators (a boom cylinder 131C, an arm cylinder 132C, a bucket cylinder 133C, the travel motors 112, and the revolution motor 124) via the control valve 123.

The control valve 123 controls a flow rate of the hydraulic oil supplied from the hydraulic pump 122.

The revolution motor 124 is driven by the hydraulic oil supplied from the hydraulic pump 122 via the control valve 123 and revolves the revolving body 120.

Configuration of Work Implement 130

The work implement 130 includes a boom 131, an arm 132, a bucket 133 as a work tool, the boom cylinder 131C, the arm cylinder 132C, and the bucket cylinder 133C. Other examples of the work tool include distal end attachments such as a clamshell bucket, a tilt bucket, a tilt rotator bucket, a grapple, and a lifting magnet.

A base end portion of the boom 131 is rotatably attached to the revolving body 120 via a boom pin. In the loading machine 100 illustrated in FIG. 1, the boom 131 is provided at a front center portion of the revolving body 120, but the position is not limited thereto, and the boom 131 may be attached offset in a left-right direction. In this case, the revolution center of the revolving body 120 is not located on an operation plane of the work implement 130.

The arm 132 couples the boom 131 and the bucket 133. A base end portion of the arm 132 is rotatably attached to a distal end portion of the boom 131 via an arm pin.

The bucket 133 is rotatably attached to a distal end portion of the arm 132 via a pin. The bucket 133 serves as a container for accommodating excavated earth and sand. The bucket 133 is attached with an opening thereof facing the revolving body 120 (rearward). That is, the loading machine 100, which is a backhoe shovel, performs excavation by pulling the bucket 133 in front of the revolving body 120.

The boom cylinder 131C is a hydraulic cylinder for actuating the boom 131. A base end portion of the boom cylinder 131C is attached to the revolving body 120. A distal end portion 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 portion of the arm cylinder 132C is attached to the boom 131. A distal end portion 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 portion of the bucket cylinder 133C is attached to the arm 132. A distal end portion of the bucket cylinder 133C is attached to a link mechanism that turns the bucket 133.

Configuration of Cab 140

FIG. 2 is a view illustrating an internal configuration of the cab 140 according to the first embodiment.

An operator seat 141, an operation terminal 142, and an operation device 143 are provided in the cab 140. The operation terminal 142 is provided in the vicinity of the operator seat 141 and is a user interface with a control device 160 described below. The operation terminal 142 is a display device constituted by a touch panel, for example, and may include an operation unit to be operated by an operator and an input reception unit that receives operations. Further, the display device displays measurement data of an engine water temperature gauge, a fuel gauge, and the like. Further, the operation terminal 142 may include a display unit such as a liquid crystal display (LCD). The touch panel is an example of a display unit. In another embodiment, the display unit and the operation unit may be provided separately.

The operation device 143 is a device for driving the traveling body 110, the revolving body 120, and the work implement 130 by manual operation by the 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 rotation brake pedal 143TB, and a start switch 143SW.

The left operation lever 143LO is provided on the left side of the operator seat 141. The right operation lever 143RO is provided on the right side of the operator seat 141.

The left operation lever 143LO is an operation mechanism for performing a revolution operation of the revolving body 120 and an excavation/dumping operation of the arm 132. Specifically, when the operator of the loading machine 100 tilts the left operation lever 143LO forward, the arm 132 performs the dumping operation. When the operator of the loading machine 100 tilts the left operation lever 143LO rearward, the arm 132 performs the excavation operation. When the operator of the loading machine 100 tilts the left operation lever 143LO rightward, the revolving body 120 revolves to the right. Further, when the operator of the loading machine 100 tilts the left operation lever 143LO leftward, the revolving body 120 revolves to the left. Note that, in another embodiment, the revolving body 120 may revolve to the right or the left when the left operation lever 143LO is tilted in a front-rear direction, and the arm 132 may perform the excavation operation or the dumping operation when the left operation lever 143LO is tilted in the left-right direction.

The right operation lever 143RO is an operation mechanism for performing the excavation/dumping operation of the bucket 133 and a raising/lowering operation of the boom 131. Specifically, when the operator of the loading machine 100 tilts the right operation lever 143RO forward, the lowering operation of the boom 131 is executed. When the operator of the loading machine 100 tilts the right operation lever 143RO rearward, the raising operation of the boom 131 is executed. When the operator of the loading machine 100 tilts the right operation lever 143RO rightward, the dumping operation of the bucket 133 is performed. Further, when the operator of the loading machine 100 tilts the right operation lever 143RO leftward, the excavation operation of the bucket 133 is performed. Note that, in another embodiment, the bucket 133 may perform the dumping operation or the excavating operation when the right operation lever 143RO is tilted in the front-rear direction, and the boom 131 may perform the raising operation or the lowering operation when the right operation lever 143RO is tilted in the left-right direction.

The left foot pedal 143LF is disposed on the left side of a floor surface in front of the operator seat 141. The right foot pedal 143RF is disposed on the right side of the floor surface in front of the operator seat 141. The left travel lever 143LT is pivotally supported by the left foot pedal 143LF and is configured so that the tilting of the left travel lever 143LT and a depression of the left foot pedal 143LF are interlocked with each other. The right travel lever 143RT is pivotally supported by the right foot pedal 143RF and is configured so that the tilting of the right travel lever 143RT and a depression of the right foot pedal 143RF are interlocked with each other.

The left foot pedal 143LF and the left travel lever 143LT correspond to the rotational driving of a left crawler track of the traveling body 110. Specifically, when the operator of the loading machine 100 tilts the left foot pedal 143LF or the left travel lever 143LT forward, the left crawler track rotates in the forward direction. Further, when the operator of the loading machine 100 tilts the left foot pedal 143LF or the left travel lever 143LT rearward, the left crawler track rotates in a rearward direction.

The right foot pedal 143RF and the right travel lever 143RT correspond to the rotational driving of a right crawler track of the traveling body 110. Specifically, when the operator of the loading machine 100 tilts the right foot pedal 143RF or the right travel lever 143RT frontward, the right crawler track rotates in a forward direction. Further, when the operator of the loading machine 100 tilts the right foot pedal 143RF or the right travel lever 143RT rearward, the right crawler track rotates in the rearward direction.

The start switch 143SW is provided, for example, at a handle portion of the left operation lever 143LO. The start switch 143SW is disposed so as to be located in the vicinity of the operator seated on the operator seat 141. When the start switch 143SW is pressed, an automatic control instruction signal is output to the control device 160. The control device 160, when receiving input of the automatic control instruction signal, starts the automatic control.

The automatic control refers to the loading machine 100 autonomously controlling the driving of the work implement 130 and the revolving body 120 in order to realize a predetermined operation. The automatic control in the first embodiment is control in which the loading machine 100 autonomously performs a first revolution (FIG. 4) which is a series of operations of revolving from a state in which the bucket 133 is positioned on the outer side of the loading target T by excavation of the excavation target to an orientation facing the loading target T while raising the boom 131, and a second revolution (FIG. 5) which is a series of operations of revolving from a state in which the bucket 133 is positioned above the loading target T by loading to a predetermined orientation while lowering the boom 131 for movement to the outer side of the loading target T. In the example illustrated in FIG. 4 and FIG. 5, since the height of the loading target T is higher than the excavation height, the boom 131 is raised in the first revolution and the boom 131 is lowered in the second revolution, but this should not be construed in a limiting sense. For example, when the height of the loading target T is lower than the excavation height, the boom 131 is lowered in the first revolution, and the boom 131 is raised in the second revolution. Note that the automatic control according to another embodiment may perform only the second revolution. In the first embodiment, target orientations of the revolving body 120 and target postures of the bucket 133 in the first revolution and the second revolution are respectively set to orientations and postures designated in advance. Typically, the excavation target is at a position lower than a height of the loading target T. Therefore, the loading machine 100 controls the driving of the work implement 130 so that the loading target T and the work implement 130 do not come into contact with each other in the first revolution and the second revolution. Details of the automatic control will be described below.

The automatic control executed each time the start switch 143SW is pressed switches between the first revolution and the second revolution. Further, in another embodiment, the operation device 143 may include two of the start switches 143SW, and the first revolution and the second revolution may be respectively assigned thereto.

Configuration of Measurement System

As illustrated in FIG. 1, the loading machine 100 includes a position and orientation calculator 151, an inclination measuring instrument 152, a boom stroke sensor 153, an arm stroke sensor 154, and a bucket stroke sensor 155.

The position and orientation calculator 151 calculates a position of the revolving body 120 and an orientation in which the revolving body 120 is directed. The position and orientation calculator 151 includes two receivers that receive positioning signals from artificial satellites constituting the global navigation satellite system (GNSS). The two receivers are installed at different positions of the revolving body 120. The position and orientation calculator 151 detects a position of a representative point (origin of shovel coordinate system) of the revolving body 120 in a site coordinate system based on the positioning signals received by the receivers.

Using the positioning signals received by the two receivers, the position and orientation calculator 151 calculates the orientation in which the revolving body 120 is directed as a relationship between an installation position of one receiver and an installation position of the other receiver. The orientation in which the revolving body 120 is directed is a direction orthogonal to a front surface of the revolving body 120. The orientation in which the revolving body 120 is directed is equal to a horizontal component in an extending direction of a straight line extending from the boom 131 to the bucket 133 of the work implement 130.

The inclination measuring instrument 152 measures an acceleration and an angular velocity of the revolving body 120, and detects a posture (for example, roll angle, pitch angle, and yaw angle) and a revolution speed of the revolving body 120 based on the measurement result. The inclination measuring instrument 152 is installed, for example, on a lower surface of the revolving body 120. As the inclination measuring instrument 152, an inertial measurement unit (IMU) can be used, for example.

The boom stroke sensor 153 is attached to the boom cylinder 131C and detects a cylinder length of the boom cylinder 131C. The cylinder length of the boom cylinder 131C can be converted into a relative angle of the boom 131 with respect to the revolving body 120.

The arm stroke sensor 154 is attached to the arm cylinder 132C and detects a cylinder length of the arm cylinder 132C. The cylinder length of the arm cylinder 132C can be converted into a 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 a cylinder length of the bucket cylinder 133C. The cylinder length of the bucket cylinder 133C can be converted into a relative angle of the bucket 133 with respect to the arm 132.

The loading machine 100 according to the first embodiment identifies an angle of each link part of the work implement 130 using the boom stroke sensor 153, the arm stroke sensor 154, and the bucket stroke sensor 155, but is not limited thereto in other embodiments. For example, in another embodiment, a potentiometer that detects a relative rotation angle of a link part may be provided, or a tilt sensor that detects a ground angle of each link part may be provided instead of the stroke sensor.

Configuration of Control Device 160

FIG. 3 is a schematic block diagram illustrating a configuration of the control device 160 according to the first embodiment.

The loading machine 100 includes the control device 160. The control device 160 may be mounted on the operation terminal 142, or may be provided separately from the operation terminal 142 and receive inputs and outputs 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 signal or an operation signal generated for the automatic control to the control valve 123. Hereinafter, the operation signal received from the operation device 143 is referred to as a manual operation signal, and the operation signal generated for the automatic control is referred to as an automatic operation signal. The automatic operation signal is composed of operation signals for driving the revolving body 120 and the work implement 130, and does not include an operation signal for driving the traveling body 110. When a manual operation signal from the operator is received during the automatic control, the control device 160 may stop the automatic control.

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 the program into the main memory 630, and executes processing according to the program.

Examples of the storage 650 include a semiconductor memory, a magnetic disk, a magneto-optical disk, an optical disk, and the like. The storage 650 may be an internal medium directly connected to a common communication line of the control device 160, or may be an external medium connected to the control device 160 via the interface 670. The main memory 630 and the storage 650 are non-transitory tangible storage media.

With execution of the program, the processor 610 includes a measurement data acquisition unit 611, an operation signal input unit 612, a work implement position identification unit 613, a reference identification unit 614, an angle identification unit 615, a remainder estimation unit 616, a movement control unit 617, and an operation signal output unit 618.

The measurement data acquisition unit 611 acquires measurement data acquired by the measurement system of the loading machine 100. Specifically, the measurement data acquisition unit 611 acquires measurement data from each of the position and orientation calculator 151, the inclination measuring instrument 152, the boom stroke sensor 153, the arm stroke sensor 154, and the bucket stroke sensor 155. The measurement data acquisition unit 611 calculates an angle of the revolving body 120 by integrating the angular velocity of the revolving body 120 measured by the inclination measuring instrument 152.

The operation signal input unit 612 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 causing the bucket 133 to dump or excavate, a drive signal for revolving the revolving body 120 to the right or left, a drive signal for causing the traveling body 110 to travel, and an automatic control instruction signal for the loading machine 100. That is, the operation signal input unit 612 is an example of an input unit that receives an input of an automatic control start instruction from an operator.

The work implement position identification unit 613 identifies a position of a distal end P of the arm 132 (FIG. 4) and a position of a lowest point Q of the bucket 133 (FIG. 4) in a vehicle coordinate system with reference to the revolving body 120 based on the measurement data acquired by the measurement data acquisition unit 611. The lowest point Q of the bucket 133 is a point of an outer shape of the bucket 133 at which a distance from a ground surface is shortest.

The work implement position identification unit 613 determines a vertical direction component and a horizontal direction component of a length of the boom 131 based on an inclination angle of the boom 131 and a known length of the boom 131 (distance from the pin at the base end portion to the pin at the distal end portion). Similarly, the work implement position identification unit 613 determines a vertical direction component and a horizontal direction component of a length of the arm 132. The work implement position identification unit 613 identifies a position separated from the position of the loading machine 100 by the sum of the vertical direction components and the sum of the horizontal direction components of the lengths of the boom 131 and the arm 132 in a direction identified from the orientation and the posture of the loading machine 100 as the position of the distal end P of the arm 132. Further, the work implement position identification unit 613 identifies the position of the lowest point Q of the bucket 133 based on an inclination angle of the bucket 133 and a known shape of the bucket 133. For example, the work implement position identification unit 613 calculates the position of each of a plurality of points on an outer shell of the bucket 133 based on the inclination angle of the bucket 133, and identifies the point having the lowest height among the plurality of points as the lowest point Q. Further, for example, the work implement position identification unit 613 may set a point obtained by downwardly offsetting a distance between a point of the bucket 113 farthest from a bucket pin and the bucket pin in a height direction from the bucket pin as the lowest point Q. Further, for example, the work implement position identification unit 613 may set a point obtained by downwardly offsetting an amount of the maximum bucket movable range in the height direction from the bucket pin as the lowest point Q. Further, the work implement position identification unit 613 may set a point offsetting the height with a margin from the height identified above, accounting for control errors and measurement errors, as the lowest point Q.

Before execution of the automatic control, the reference identification unit 614 receives teaching of an excavation preparation position, a collision avoidance position, and a loading position of the bucket 133 from the operator as reference points of the automatic control. The teaching is performed by the following procedure, for example.

The reference identification unit 614 causes the operation terminal 142 to display an instruction for moving the bucket 133 to the excavation preparation position that is a position for the excavation. The operator operates the operation device 143 to move the bucket 133 to the excavation preparation position, and inputs completion of movement to the excavation preparation position to the operation terminal 142. The reference identification unit 614 records, in the storage 650, the posture of the work implement 130 identified by the work implement position identification unit 613 as the target posture of the second revolution, the position of the distal end P of the arm 132 as the target position of the second revolution, and the orientation in which the revolving body 120 is directed as the target orientation of the second revolution. Next, the reference identification unit 614 causes the operation terminal 142 to display an instruction for moving a cutting edge of the bucket 133 to the collision avoidance position corresponding to a position higher than a height of an upper end of a wall of the vessel of the loading target T and where the work implement 130 and the loading target T do not overlap in plan view from above. The operator operates the operation device 143 to move the cutting edge of the bucket 133 to the collision avoidance position, and inputs completion of movement to the collision avoidance position to the operation terminal 142. The collision avoidance positions may be input with respect to both a right end and a left end of the loading target T. The collision avoidance position may be either one of the right end and the left end of the loading target T. Accordingly, the reference identification unit 614 can identify the range of the loading platform of the loading target T. Note that a height of each collision avoidance position may be a height obtained by offsetting the height with a margin in an upward direction accounting for control errors and measurement errors.

The reference identification unit 614 records, in the storage 650, the orientation in which the revolving body 120 is directed, as the collision avoidance orientation.

Next, the reference identification unit 614 causes the operation terminal 142 to display an instruction for moving the bucket 133 to the loading position above the loading target T. The operator operates the operation device 143 to move the bucket 133 to the loading position, and inputs completion of movement to the loading position to the operation terminal 142. The reference identification unit 614 records, in the storage 650, the posture of the work implement 130 as the target posture of the first revolution, the position of the distal end P of the arm 132 as the target position of the first revolution, and the orientation in which the revolving body 120 is directed identified by the work implement position identification unit 613 as the target orientation of the first revolution.

The reference identification unit 614 receives an input of the loading posture of the bucket 133 from the operator via the operation terminal 142. For example, the operator manually inputs a bucket angle in a state where the loading operation is completed to the operation terminal 142, as the loading posture. For example, the operator operates the operation device 143 to make the bucket 133 take a posture upon completion of the loading operation, and inputs the loading posture to the operation terminal 142. The loading posture of the bucket 133 is a posture tilted enough for all the load held in the bucket 133 to fall. The loading posture is identified as a posture related to the vehicle coordinate system with reference to the revolving body 120. The reference identification unit 614 records the loading posture in the storage 650. The position and the posture identified by the reference identification unit 614 may be corrected based on vehicle body inclination information such as the pitch angle and the roll angle of the revolving body 120 measured by the inclination measuring instrument 152. For example, the loading posture may be represented as a posture with respect to a horizontal plane, instead of the vehicle coordinate system.

The angle identification unit 615 identifies, as a target revolution angle, an angle between an initial orientation in which the revolving body 120 is directed when the automatic control instruction signal is input to the operation signal input unit 612 and the target orientation recorded in the storage 650. The angle identification unit 615 identifies, as a collision avoidance angle, an angle between the initial orientation in which the revolving body 120 is directed when the automatic control instruction signal is input to the operation signal input unit 612 and a collision avoidance orientation recorded in the storage 650. The collision avoidance angle is such a revolution angle that when the revolving body 120 is revolved to the collision avoidance angle, the work implement 130 and the loading target T do not overlap each other in plan view from above.

The remainder estimation unit 616 estimates whether a load is remaining in the bucket 133. The posture of the bucket 133 identified by the work implement position identification unit 613 is compared with the loading posture of the bucket 133 recorded in the storage 650, and whether the inclination angle of the bucket 133 in the vehicle coordinate system is equal to or greater than the inclination angle related to the loading posture is determined. The remainder estimation unit 616 estimates that the load is remaining in the bucket 133, when the inclination angle of the bucket 133 is less than the inclination angle related to the loading posture, that is, when the loading posture involves larger inclination toward the dump side than the posture of the bucket 133. On the other hand, the remainder estimation unit 616 estimates that the load is not remaining in the bucket 133, when the inclination angle of the bucket 133 is equal to or greater than the inclination angle related to the loading posture, that is, when the posture of the bucket 133 involves larger inclination toward the dump side than the loading posture. The inclination angle of the bucket 133 used for the comparison by the remainder estimation unit 616 may be corrected while taking into account the vehicle body inclination information such as the pitch angle and the roll angle of the revolving body 120 measured based on the inclination measuring instrument 152.

When the operation signal input unit 612 receives input of the automatic control instruction signal, the movement control unit 617 generates an automatic operation signal for realizing the automatic control. When the automatic control instruction signal is input, automatic control for realizing the first revolution for moving the bucket 133 to the loading position or automatic control for realizing the second revolution for moving the bucket 133 to the excavation preparation position is executed. The movement control unit 616 determines whether to execute the first revolution or to execute the second revolution in the automatic control depending on whether the bucket 133 is within the range of the loading platform of the loading target T in plan view from above when the automatic control instruction signal is input. When the bucket 133 is not within the range of the loading platform of the loading target T in plan view from above, the movement control unit 616 executes the first revolution, and when the bucket 133 is within the range of the loading platform of the loading target T in plan view from above, the movement control unit 616 executes the second revolution. At this time, based on the collision avoidance angle stored in the storage 650, the movement control unit 616 controls the revolving body 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.

Specifically, in the first revolution, the movement control unit 617 causes the revolving body 120 and the work implement 130 to realize a combined operation before reaching a first collision avoidance angle θ1 (FIG. 4). The work implement 130 and the loading target T do not overlap each other in plan view from above, while the revolving body 120 is revolving to the first collision avoidance angle θ1. In the first revolution, when the height of the bucket 133 does not reach the height of the loading position before the revolution angle of the revolving body 120 reaches the first collision avoidance angle θ1 (FIG. 4), a revolution operation signal for the revolving body 120 is not generated, and only an operation signal for the work implement 130 is generated. For example, only the boom raising operation is performed in the combined operation in the first revolution. On the other hand, when the height of the bucket 133 reaches the height of the loading position before the revolution angle by revolution reaches the first collision avoidance angle θ1, the movement control unit 617 generates a revolution operation signal for the revolving body 120 and an operation signal for the work implement 130 and realizes a combined operation of the revolving body 120 and the work implement 130. That is, in the combined operation in the first revolution, the raising operation of the boom 131 and the operation of revolving the revolving body 120 are performed simultaneously. After the height of the bucket 133 reaches the height of the loading position at the first collision avoidance angle θ1 (FIG. 4), the movement control unit 617 causes the revolving body 120 to revolve without moving the work implement 130.

Further, the movement control unit 616 performs control so that the lowest point of the bucket 133 is not lowered before the revolution angle of the revolving body 120 reaches a second collision avoidance angle θ2 (FIG. 5) in the second revolution of a revolution opposite to the first revolution. The control in which the lowest point is not lowered may be control in which the revolving body 120 is revolved without moving the work implement 130 while maintaining the height of the lowest point, or may be control in which a gap is provided between the loading target T and the bucket 133 by making the lowest point higher than the lowest point before control. When the revolving body 120 revolves to the second collision avoidance angle θ2, the state where the work implement 130 and the loading target T overlap in plan view from above transitions to a state without the overlap. After the revolution angle reaches the second collision avoidance angle θ2, the movement control unit 616 generates a revolution operation signal for the revolving body 120 and an operation signal for the work implement 130 to realize a combined operation of the revolving body 120 and the work implement 130. However, in a case where the remainder estimation unit 616 estimates that the load is remaining in the bucket 133 when the input of the automatic control instruction signal is received in the second revolution, the movement control unit 616 rotates the bucket 133 in a dumping direction, before revolving the revolving body 120. For example, the movement control unit 616 may rotate the bucket 133 in the dumping direction while revolving the revolving body 120. The movement control unit 616 preferably revolves the revolving body 120 while rotating the bucket 133 in the dumping direction, at a low revolution speed compared with the case where the bucket 133 is not rotated in the dumping direction. Rotating the bucket 133 in the dumping direction is one mode of output of the result of estimating whether the load is remaining in the bucket 133. Not rotating the bucket 133 in the dumping direction is one mode of output of the result of estimating whether the load is remaining in the bucket 133. Rotating the bucket 133 in the dumping direction is an operation for dumping the load in the bucket 133. That is, rotating the bucket 133 in the dumping direction is an example of discharging the load.

The operation signal output unit 618 outputs, to the control valve 123, the manual operation signal input to the operation signal input unit 612 or the automatic operation signal generated by the movement control unit 616. Thus, the operation signal output unit 618 is an example of an output unit configured to provide an output based on a result of estimating whether the load is remaining in the bucket 133.

Operation during Automatic Control

Here, movement of the loading machine 100 during the automatic control according to the first embodiment will be described with reference to the drawings.

FIG. 4 is a view illustrating an example of the movement of the loading machine 100 in the first revolution according to the first embodiment. FIG. 5 is a view illustrating an example of the movement of the loading machine 100 in the second revolution according to the first embodiment.

When the automatic control according to the first revolution starts, the control device 160, as illustrated in FIG. 4, first starts driving the work implement 130 (the boom 131, the arm 132, and the bucket 133), and moves the bucket 133 upward by the raising operation of the boom 131. The target position of the bucket 133 according to the first revolution is the loading position above the loading target T. After a delay, the control device 160 starts revolution of the revolving body 120. The control device 160 adjusts a revolution start timing so that the posture of the work implement 130 reaches the target posture according to the first revolution before the revolution angle of the revolving body 120 matches the first collision avoidance angle θ1. Note that, before the revolution angle of the revolving body 120 matches the first collision avoidance angle θ1, when the posture of the work implement 130 reaches the target posture in the first revolution, that is, when the height of the lowest point Q of the bucket 133 is higher than the height of the upper end of the wall of the vessel of the loading target T, the work implement 130 will not come into contact with the loading target T by the revolution of the revolving body 120. Subsequently, when the bucket 133 reaches the loading position, the automatic control is ended. Subsequently, the operator manually performs the dumping operation in which the bucket 133 is turned in a dumping direction.

The operator may start the automatic control related to the second revolution in a state where the load is remaining in the bucket 133. When the automatic control according to the second revolution starts, the control device 160 determines whether the load is remaining in the bucket 133. Specifically, the posture of the bucket 133 identified by the work implement position identification unit 613 is compared with the loading posture of the bucket 133 recorded in the storage 650, and whether the inclination angle of the bucket 133 in the vehicle coordinate system is equal to or greater than the inclination angle related to the loading posture is determined. When the load is estimated to be remaining in the bucket 133, the bucket 133 is rotated in the dumping direction. When the loading posture is reached, the revolution of the revolving body 120 starts. Until the revolution angle of the revolving body 120 exceeds the second collision avoidance angle θ2, the control device 160 revolves the revolving body 120 without moving the work implement 130 and maintains the height of the lowest point of the bucket 133. When the revolution angle of the revolving body 120 exceeds the second collision 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 some of the boom 131, the arm 132, and the bucket 133 based on the relationship between the posture at the timing of starting revolution and the target posture. When the revolution angle of the revolving body 120 reaches the target revolution angle 00, the control device 160 ends the driving of the revolving body 120. Further, when the posture of the work implement 130 reaches the target posture at the timing of starting excavation, the control device 160 ends the driving of the work implement 130.

FIGS. 4 and 5 illustrate an example in which a positional relationship between the excavation position and the loading target T is approximately 90 degrees about the revolving body 120, but the positional relationship is not limited thereto in other embodiments. For example, in another embodiment, the positional relationship between the excavation position and the loading target T may be another revolution angle position such as approximately 180 degrees about the revolving body 120.

Operation of Control Device 160

FIG. 6 is a flowchart illustrating first revolution control by the control device 160 according to the first embodiment. FIG. 7 is a flowchart illustrating second revolution control by the control device 160 according to the first embodiment.

When the start switch 143SW is pressed by the operator, the operation signal input unit 612 of the control device 160 receives input of an automatic control instruction signal. When the automatic loading instruction signal is input, the control device 160 determines whether to execute the first revolution or to execute the second revolution based on whether the bucket 133 is within the range on the loading platform of the loading target T in plan view from above. When the bucket 133 is within the range of the loading platform of the loading target T, the second revolution is executed. When the bucket 133 is outside the range of the loading platform of the loading target T, the first revolution is executed.

In executing the first revolution, the control device 160 executes the first revolution control illustrated in FIG. 6. First, the measurement data acquisition unit 611 acquires the measurement data of the orientation of the loading machine 100 (step S1). The movement control unit 616 reads the target orientation (orientation of the loading target T) of the revolving body 120, the target posture, and the collision avoidance orientation from the storage 650 (step S2). The angle identification unit 615 identifies the target revolution angle θ0 and the first collision avoidance angle θ1 based on the orientation in which the revolving body 120 is directed identified in step S1 and the target orientation and the collision avoidance orientation read in step S2 (step S3).

Next, the measurement data acquisition unit 611 acquires the measurement data of each of the position, the orientation, the inclination angle, and the revolution speed of the loading machine 100, and the measurement data of the cylinder length of each cylinder, and the work implement position identification unit 613 identifies the posture of the work implement 130 based on the measurement data (step S4). The measurement data acquisition unit 611 may acquire the measurement data of each of the orientation, the inclination angle, and the revolution speed of the loading machine 100, and the measurement data of the cylinder length of each cylinder, and the work implement position identification unit 613 may identify the posture of the work implement 130 based on the measurement data. Thus, the work implement position identification unit 613 may identify the posture of the work implement 130 without referring to the position of the loading machine 100. The work implement position identification unit 613 identifies the position of the distal end P of the arm 132, the position of the lowest point Q of the bucket 133, and the posture of the bucket 133 (step S5).

The movement control unit 617 generates an automatic operation signal for moving the bucket 133 to above the loading target T based on the target orientation and the target posture read in step S2 and the first collision avoidance angle θ1 identified in step S3. That is, the movement control unit 617 generates the automatic operation signal so that the bucket 133 reaches the loading position represented by the target orientation and the target posture via the collision avoidance position represented by the first collision avoidance angle θ1. At this time, the movement control unit 617 generates an automatic operation signal for the bucket 133 so that the ground angle of the bucket 133 does not change even when the boom 131 and the arm 132 are driven.

Specifically, the movement control unit 617 generates the automatic operation signal by the following procedure.

First, the movement control unit 617 determines whether the posture of the work implement 130 identified in step S5 approximates the target posture acquired in step S1 (step S6). For example, when a difference between the position of the distal end of the arm 132 in the target posture and the current position of the distal end of the arm 132 is equal to or less than a predetermined value, the movement control unit 617 determines that the posture of the work implement 130 is approximate to the target posture.

When the posture of the work implement 130 is not approximate to the target posture (step S6: NO), the movement control unit 617 generates an automatic operation signal for bringing the boom 131 and the arm 132 close to the target posture (step S7). At this time, the movement control unit 616 generates the automatic operation signal based on the positions and the speeds of the boom 131 and the arm 132 identified from the measurement data acquired in step S4.

Further, the movement control unit 617 calculates the sum of the driving speeds of the boom 131 and the arm 132 based on the generated automatic operation signal of the boom 131 and the arm 132, and generates an automatic operation signal for driving the bucket 133 at the same speed as the sum of the driving speeds (step S8). Thus, the movement control unit 617 can generate an operation signal for keeping the ground angle of the bucket 133.

The movement control unit 617 determines whether the work implement 130 is revolving (step S9). For example, when the revolution speed of the revolving body 120 is equal to or higher than a predetermined speed, the movement control unit 617 determines that the revolution is implemented. When the work implement 130 is not revolving (step S9: NO), the movement control unit 617 calculates a completion time for the work implement 130 to reach the target posture based on the speeds of the boom 131 and the arm 132 identified in step S7 (step S10).

Further, the movement control unit 617 calculates an arrival time for the revolution angle to reach the first collision avoidance angle 01 identified in step S3 when the revolving body 120 starts revolving (step S11). The movement control unit 617 determines whether the completion time calculated in step S10 is less than the arrival time calculated in step S11 (step S12). That is, the movement control unit 617 determines whether the work implement 130 will be in the target posture when the revolution angle reaches the first collision avoidance angle θ1.

When the completion time is equal to or longer than the arrival time (step S12: NO), that is, when the work implement 130 will not assume the target posture before the revolution angle reaches the first collision avoidance angleθ1, the movement control unit 617 does not generate a revolution operation signal for the revolving body 120. On the other hand, when the completion time is less than the arrival time (step S12: YES), that is, when the work implement 130 will assume the target posture before the revolution angle reaches the first collision avoidance angle θ1, the movement control unit 617 generates a revolution operation signal for the revolving body 120 (step S13). As a result, the control device 160 can prevent contact with the loading target T due to revolution while the height of the work implement 130 remains low.

The operation signal output unit 618 outputs the generated automatic operation signal to the control valve 123 (step S14). Thus, the loading machine 100 is driven. Then, the control device 160 returns the processing to step S4 and continues the control.

On the other hand, when the determination is made in step S9 that the work implement 130 is revolving (step S9: YES), the movement control unit 617 determines whether the revolution angle will reach the target revolution angle by revolution due to inertia when the revolution operation signal is stopped, based on the revolution speed of the work implement 130 identified in step S4 (step S15). When the revolution angle will not reach the target revolution angle by revolution due to inertia (step S15: NO), the movement control unit 617 generates a revolution operation signal in step S13, and the operation signal output unit 617 outputs the revolution operation signal to the control valve 123 in step S14.

On the other hand, when the determination is made that the revolution angle will reach the target revolution angle by revolution due to inertia (step S15: YES), whether the revolution angle has reached the target revolution angle and the posture of the work implement 130 is the target posture (step S16) are determined. When the revolution angle has reached the target revolution angle, but the posture of the work implement 130 is not the target posture (step S16: NO), the control device 160 returns the processing to step S4.

On the other hand, when the revolution angle has reached the target revolution angle and the posture of the work implement 130 is the target posture (step S16: YES), the control device 160 ends the first revolution processing.

FIG. 7 is a flowchart illustrating the second revolution control by the control device 160 according to the first embodiment.

When the start switch 143SW is pressed by the operator, the operation signal input unit 612 of the control device 160 receives input of an automatic control instruction signal.

In executing the second revolution, the control device 160 executes the second revolution control illustrated in FIG. 7. First, the measurement data acquisition unit 611 acquires the measurement data of the orientation of the loading machine 100 (step S21). The movement control unit 617 reads the target orientation (orientation directed to the outer side of the loading target T) of the revolving body 120, the target posture, and the collision avoidance orientation from the storage 650 (step S 22). The angle identification unit 615 identifies the target revolution angle θ0 and the second collision avoidance angle θ2 based on the orientation in which the revolving body 120 is directed identified in step S21 and the target orientation and the collision avoidance orientation read in step S22 (step S23).

Next, the measurement data acquisition unit 611 acquires the measurement data of each of the position, the orientation, the inclination angle, and the revolution speed of the loading machine 100, and the measurement data of the cylinder length of each cylinder, and the work implement position identification unit 613 identifies the posture of the work implement 130 based on the measurement data (step S24). The work implement position identification unit 613 identifies the position of the distal end P of the arm 132, the position of the lowest point Q of the bucket 133, and the posture of the bucket 133 (step S25).

The remainder estimation unit 616 compares the posture of the bucket 133 identified in step S25 with the loading posture recorded in the storage 650, and estimates whether the load may be remaining in the bucket 133 (step S26). When the load is estimated to be remaining in the bucket 133 (step S26: YES), the movement control unit 617 generates an automatic operation signal for rotating the bucket 133 in the dumping direction (step S27). The automatic operation signal for rotating the bucket 133 is a signal for operating the bucket 133 based on an arbitrary speed target value of the bucket axis called from the storage 650. The speed target value is a constant speed. The automatic operation signal for moving the bucket 133 in the dumping direction may be, for example, a signal for rotating the arm 132 in the dumping direction to move the bucket 133 in the dumping direction with respect to the horizon. The automatic operation signal for rotating the bucket 133 may be a signal for moving the arm 132 and the bucket 133 at the same time to realize dumping. The movement control unit 617 generates an automatic operation signal for the boom 131 to cancel a change in the height of the lowest point Q due to the rotation of the bucket 133 (step S28). When the height of the lowest point Q increases with the rotation of the bucket 133, the movement control unit 617 rotates only the bucket 133. At this time, the movement control unit 616 does not generate an automatic operation signal for revolving the revolving body 120. Thereafter, the control device 160 outputs the automatic operation signal for rotating the bucket 133 (step S29). Subsequently, the control device 160 returns the processing to step S24.

On the other hand, when the load is estimated not to be remaining in the bucket 133 (step S26: NO), the movement control unit 617 determines whether the revolution angle of the work implement 130 will reach the target revolution angle by revolution due to inertia when the revolution operation signal is stopped, based on the measurement data of the revolution speed of the work implement 130 identified in step S24 (step S30). When the revolution angle of the work implement 130 will not reach the target revolution angle by the revolution due to inertia (step S30: NO), the movement control unit 616 generates an automatic operation signal for revolving the revolving body 120 (step S31). The automatic operation signal is an operation signal for revolving the bucket 133 from the inner side of the loading target T to the outer side of the loading target T in plan view from above.

Next, the movement control unit 616 determines whether the revolution angle of the revolving body 120 from the timing of starting the automatic control to the current time is less than the second collision avoidance angle θ2 (step S32). When the revolution angle is less than the second collision avoidance angle θ2 (step S32: YES), the movement control unit 616 generates an operation signal (neutral signal) for maintaining the posture of the work implement 130.

In step S32, when the revolution angle is equal to or greater than the second collision avoidance angle θ2 (step S32: NO), the movement control unit 616 determines whether the posture of the work implement 130 identified in step S24 approximates the target posture identified in step S22 (step S33). When the posture of the work implement 130 is not approximate to the target posture (step S33: NO), the movement control unit 616 generates an automatic operation signal for bringing the boom 131, the arm 132, and the bucket 133 close to the target posture (step S34). When the posture of the work implement 130 is close to the target posture (step S33: YES), the movement control unit 616 generates a neutral signal for maintaining the posture of the work implement 130.

Then, the operation signal output unit 617 outputs the generated automatic operation signal to the control valve 123 (step S35). The movement control unit 616 determines whether the revolution angle has reached the target revolution angle and the posture of the work implement 130 is the target posture (step S36). When the revolution angle has not reached the target revolution angle or the posture of the work implement 130 is not in the target posture (step S36: NO), the control device 160 returns the processing to step S24. On the other hand, when the revolution angle has reached the target revolution angle and the posture of the work implement 130 is in the target posture (step S36: YES), the automatic control processing is ended.

Actions and Effects As described above, the control device 160 according to the first embodiment estimates whether the load is remaining in the bucket 133 at the timing of starting the automatic control related to the second revolution for moving the bucket 133 from above the loading target T to the outer side of the loading target T, and outputs the automatic operation signal for moving the bucket 133 in the dumping direction upon estimating that the load is remaining in the bucket 133. When the load is estimated not to be remaining in the bucket 133 thereafter, an automatic operation signal related to the second revolution is output. Accordingly, the load in the bucket 133 bucket can be prevented from being spilled on the outer side of the loading target T, even when the automatic control start instruction is input in a state where the load is remaining in the bucket 133.

Note that, the control device 160 according to another embodiment may not output the automatic operation signal for moving the bucket 133 in the dumping direction when the load is estimated to be remaining in the bucket 133, and may not simply output the automatic operation signal related to the second revolution. In this case, the control device 160 may cause the operation terminal 142 to output an alert. In this case, the operator upon visually confirming the alert presses the start switch 143SW again after the load is completely discharged from the bucket 133. Then, the second revolution is executed. Also with such a configuration, the load in the bucket 133 can be prevented from spilling on the outer side the loading target T.

Further, the control device 160 according to another embodiment may not perform the automatic control. That is, the control device 160 according to another embodiment may estimate whether the load is remaining in the bucket 133 under a manual operation, and may output the estimation result to the operation terminal 142. In this case, the control device 160 may estimate whether the load is remaining in the bucket 133 at the time of the loading work, and may display the estimation result on the operation terminal 142. This enables the operator to determine whether the load has been completely unloaded from the bucket 133 in the loading work. In this case, the operation terminal 142 is an example of the output unit configured to provide an output based on the result of estimating whether the load is remaining in the bucket 133.

Other Embodiments

An embodiment has been described above in detail with reference to the drawings, but a specific configuration is not limited to that described above, and various design changes and the like can be made. That is, in other embodiments, the order of the processing described above may be changed as appropriate. Further, some processing may be executed in parallel.

The control device 160 according to the embodiment described above may be constituted by a single computer. The configuration of the control device 160 may be divided into a plurality of computers, and the plurality of computers may cooperate with each other and serve as the control device 160. At this time, some of the computers constituting the control device 160 may be mounted inside the loading machine 100, and the other computers may be provided outside of the loading machine 100.

The control device 160 according to the above-described embodiment estimates that the load is remaining in the bucket 133 when the posture of the bucket 133 has not reached the loading posture, but this should not be construed in a limiting sense. For example, in another embodiment, when the work implement 130 includes a payload sensor, the control device 160 may estimate whether the load is remaining in the bucket 133 based on measurement data of the payload sensor. The payload sensor may be, for example, a sensor that estimates the weight of the load based on measurement information of pressure sensors mounted on the bottom side and the head side of a work implement cylinder (boom cylinder, arm cylinder, or bucket cylinder) and a work implement posture angle. In another embodiment, when the loading machine 100 includes a camera, the control device 160 may estimate whether the load is remaining in the bucket 133 by analyzing a portion of the bucket 133 in an image captured by the camera. For example, the control device 160 may estimate whether the posture of the bucket 133 is a predetermined dumping posture based on the captured image including the bucket 133, determine that the load is not remaining when the posture of the bucket 133 is the dumping posture, and determine that the load is remaining when the posture of the bucket 133 has not reached the dumping posture. In addition, when the captured image including the bucket 133 includes an image inside the bucket 133, the control device 160 may estimate whether the load is remaining based on the image inside the bucket. In another embodiment, the control device 160 may receive measurement data of a payload sensor provided to the loading target T and estimate whether the load is remaining in the bucket 133 based on an amount of change in the measurement data.

The target posture, the target orientation, and the collision avoidance orientation according to the embodiment described above are recorded in the storage 650 by teaching, but this should not be construed in a limiting sense. For example, the loading machine 100 according to another embodiment may recognize the position and a shape of the loading target T by being provided with a three-dimensional measurement device such as a stereo camera or light detection and ranging (LiDAR), and may identify the target posture, the target orientation and the collision avoidance orientation based on the position and the shape. Further, in another embodiment, the position, and the orientation of the loading target T may be received through communication with the loading target T, and the target posture, the target orientation and the collision avoidance orientation may be identified based on the position, the posture, and the orientation of the loading target T and the known shape of the loading target T. In another embodiment, when the loading target T automatically travels by communication with the control apparatus, the position and the orientation of the loading target T may be received from the control apparatus, and the target posture, the target orientation and the collision avoidance orientation may be identified based on the position and the orientation of the loading target T and the known shape of the loading target T.

Further, the loading posture according to the above-described embodiment is identified by an input to the operation terminal 142, but is not limited thereto, and may be identified by teaching.

Further, the control device 160 according to the embodiment described above identifies the posture of the work implement 130 based on the measurement data of the sensor that measures the posture of the work implement 130, but is not limited thereto. For example, in another embodiment, when the loading machine 100 includes a three-dimensional measurement device such as a stereo camera or a LiDAR, the posture of the work implement 130, in particular, the height of the lowest point Q of the bucket 133, may be recognized based on the measurement data of the three-dimensional measurement device, and the automatic control may be performed based on the recognized posture.

The control device 160 according to the embodiment described above calculates the angle of the revolving body 120 by integrating the angular velocity of the revolving body 120 measured by the inclination measuring instrument 152, but is not limited thereto. For example, the control device 160 according to another embodiment may calculate the angle of the revolving body 120 based on a difference in orientation measured by the position and orientation calculator 151. In another embodiment, the angle of the revolving body 120 may be identified using a detection value of a rotation angle sensor provided in the revolution motor 124.

The control device 160 according to the embodiment described above performs the automatic control based on the comparison between the revolution angle and the collision avoidance angle, but is not limited thereto. For example, the control device 160 according to another embodiment may perform the automatic control based on a comparison between the position of the bucket 133 and a rearmost point of the outer shape of the loading target T in the revolution direction of the revolving body 120. For example, the control device 160 according to another embodiment may adjust the revolution start timing so that the bucket 133 is positioned in a region in the vicinity of the rearmost point in the revolution direction of the revolving body 120.

Further, in another embodiment, the control device 160 may generate an automatic control signal for each link part and the revolving body 120 so that the bucket 133 passes through a trajectory designated in advance. For example, the trajectory may be determined by fitting with a predetermined curve function, or may be determined by teaching by a manual operation. The trajectory may be represented by a time-series arrangement of the postures of the bucket 133, the postures of the link parts and the revolving body 120, or the operation signals.

The loading machine 100 according to the embodiment described above is directly operated by the operator riding in the cab 140, but is not limited thereto. For example, the loading machine 100 according to another embodiment may be operated by remote operation. That is, in another embodiment, an operation signal may be transmitted to the control device 160 by communication from the operation device 143 remotely provided. The control device 160 may be constituted by a computer provided in a remote location, or may be constituted by a control system in which functions are divided between computers provided in the loading machine 100 and the remote location.

In the automatic control according to the embodiment described above, the first revolution in which the bucket 133 is moved from the position at the time of completion of excavation to the loading point and the second revolution in which movement to the position for starting the next excavation occurs are respectively executed, but the automatic control is not limited thereto. For example, in another embodiment, the control device 160 may perform the fully automatic control for automatically executing a series of operations of a first revolution operation, an earth discharge operation, and a second revolution operation. Further, for example, in another embodiment, the control device 160 may execute only the second revolution without executing the first revolution.

Further, the automatic control according to the embodiment described above is started by the pressing of the start switch 143SW by the operator, but is not limited thereto. For example, in another embodiment, the control device 160 may autonomously determine the start timing of the automatic control and start the automatic control regardless of the pressing of the start switch 143SW.

REFERENCE SIGNS LIST

100 Loading machine, 110 Traveling body, 111 Endless track, 112 Travel motor, 120 Revolving body, 121 Engine, 122 Hydraulic pump, 123 Control valve, 124 Revolution motor, 130 Work implement, 131 Boom, 131C Boom cylinder, 132 Arm, 132C Arm cylinder, 133 Bucket, 133C Bucket cylinder, 140 Cab, 141 Operator seat, 142 Operation terminal, 143 Operation device, 151 Position and orientation calculator, 152 Inclination measuring instrument, 153 Boom stroke sensor, 154 Arm stroke sensor, 155 Bucket stroke sensor, 160 Control device, 610 Processor, 611 Measurement data acquisition unit, 612 Operation signal input unit, 613 Work implement position identification unit, 614 Reference identification unit, 615 Angle identification unit, 616 Remainder estimation unit, 617 Movement control unit, 618 Operation signal output unit, 630 Main memory, 650 Storage, 670 Interface, T Loading target

Claims

1. A control device for a work machine including a revolving body configured to revolve about a revolution center, a support part configured to support the revolving body, and a work implement that is attached to the revolving body and includes a work tool, the control device comprising:

a remainder estimation unit configured to estimate whether a load is remaining in the work tool; and

an output unit configured to provide an output based on a result of the estimation on whether the load is remaining in the work tool.

2. The control device for a work machine according to claim 1, wherein the output unit outputs an automatic operation signal that makes the revolving body revolve from an inner side toward an outer side of the loading target when the load is estimated to be not remaining in the work tool at a timing of starting automatic control to move the work tool from above the loading target to the outside of the loading target, and does not output the automatic operation signal that makes the revolving body revolve from the inner side toward the outer side of the loading target when the load is estimated to be remaining in the work tool at the timing of starting the automatic control.

3. The control device for a work machine according to claim 2, wherein the automatic operation signal that makes the revolving body revolve from the inner side to the outer side of the loading target is an automatic operation signal that makes the revolving body revolve from the inner side to the outer side of the loading target in plan view from above.

4. The control device for a work machine according to claim 2, wherein the output unit

outputs an automatic operation signal that makes the work implement discharge the load when the load is estimated to be remaining in the work tool at the timing of starting the automatic control, and

outputs the automatic operation signal that makes the revolving body revolve from the inner side to the outer side of the loading target after the load is estimated to be not remaining in the work tool.

5. The control device for a work machine according to claim 4, the automatic operation signal that causes the discharging of the load from the work implement is an automatic operation signal that causes the discharging of the load from the work implement while revolving the revolving body.

6. The control device for a work machine according to claim 5, wherein a revolution speed related to the automatic operation signal that causes the discharging of the load from the work implement revolving is lower than a revolution speed of the work implement revolving without the discharging of the load.

7. The control device for a work machine according to claim 1, wherein the remainder estimation unit estimates the load to be remaining in the work tool when the posture of the work tool has not reached the loading posture.

8. The control device for a work machine according to claim 1, wherein the remainder estimation unit estimates whether the load is remaining in the work tool when the work tool is located on the inner side of the loading target in plan view from above the loading target.

9. The control device for a work machine according to claim 1, wherein the remainder estimation unit estimates whether the load is remaining in the work tool based on the posture of the work implement.

10. The control device for a work machine according to claim 1, wherein the remainder estimation unit estimates whether the load is remaining in the work tool based on the posture of the work tool.

11. The control device for a work machine according to claim 1, wherein the remainder estimation unit estimates whether the load is remaining in the work tool using at least cylinder pressure sensor information of the work implement.

12. The control device for a work machine according to claim 2, further comprising an input unit configured to receive input of a start instruction of the automatic control from an operator.

13. A control method for a work machine including a revolving body configured to revolve about a revolution center, a support part configured to support the revolving body, and a work implement that is attached to the revolving body and includes a work tool, the control method comprising

estimating whether a load is remaining in the work tool; and

providing an output based on a result of the estimation on whether the load is remaining in the work tool.

14. A remote operation system for a work machine including a revolving body configured to revolve about a revolution center, a support part configured to support the revolving body, and a work implement that is attached to the revolving body and includes a work tool, the remote operation system comprising:

a remainder estimation unit configured to estimate whether a load is remaining in the work tool; and

an output unit configured to provide an output based on a result of the estimation on whether the load is remaining in the work tool.

15. The control device for a work machine according to claim 2, wherein the remainder estimation unit estimates the load to be remaining in the work tool when the posture of the work tool has not reached the loading posture.

16. The control device for a work machine according to claim 2, wherein the remainder estimation unit estimates whether the load is remaining in the work tool when the work tool is located on the inner side of the loading target in plan view from above the loading target.

17. The control device for a work machine according to claim 2, wherein the remainder estimation unit estimates whether the load is remaining in the work tool based on the posture of the work implement.

18. The control device for a work machine according to claim 2, wherein the remainder estimation unit estimates whether the load is remaining in the work tool based on the posture of the work tool.

19. The control device for a work machine according to claim 2, wherein the remainder estimation unit estimates whether the load is remaining in the work tool using at least cylinder pressure sensor information of the work implement.

20. The control device for a work machine according to claim 3, further comprising an input unit configured to receive input of a start instruction of the automatic control from an operator.