Work machine control system, work machine control method, and work machine remote operation system

Abstract

This work machine control system automatically operates a rotation braking device when a work machine is driven without the operation of a rotating body.

Description

Work machine control system, work machine control method, and work machine remote control system

[0001] This disclosure relates to a work machine control system, a work machine control method, and a work machine remote operation system. This application claims priority to Japanese Patent Application No. 2023-123066, filed on July 28, 2023, the contents of which are incorporated herein by reference.

[0002] Patent Document 1 discloses a technique relating to a work machine that performs automatic excavation processing.

[0003] Japanese Patent Application Laid-Open No. 2020-041354

[0004] Excavation and earth removal operations using a work machine equipped with a work implement supported on a rotating body are typically performed by driving the work implement without rotating the rotating body. However, depending on the environment, the rotating body may rotate during work even when the rotation of the rotating body is not being operated. For example, when digging using one side of the bucket, such as when digging the wall of a trench, the load on the bucket may become unbalanced between the left and right sides, generating a moment at the center of rotation of the rotating body that receives the reaction force, which may cause the rotating body to rotate. Furthermore, when the work machine is parked on a slope, a moment may be generated due to gravity, causing the rotating body to rotate. An object of the present disclosure is to provide a work machine control system, a work machine control method, and a work machine remote control system that can prevent unintended rotation during work.

[0005] According to one aspect of the present invention, a control system for a work machine is a control system for a work machine that includes a rotating body that can rotate around a rotation center, a work implement attached to the rotating body, and a rotation braking device that stops the rotation of the rotating body, and includes a brake control unit that activates the rotation braking device when the rotating body is not being operated and the work implement is being driven.

[0006] According to the above aspect, the control system for the work machine can prevent unintended turning from occurring while the work machine is working.

[0007] 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 configuration of the interior of a driver's cab according to the first embodiment; FIG. 3 is a schematic block diagram showing the configuration of a swing parking brake according to the first embodiment; FIG. 4 is a diagram showing an example of a target trajectory according to the first embodiment; FIG. 5 is a flowchart showing an automatic excavation control method according to the first embodiment; FIG. 6 is a diagram showing the configuration of a swing motor according to a second embodiment; and FIG. 7 is a flowchart showing an automatic excavation control method according to a third embodiment.

[0008] The following describes the embodiments in detail with reference to the drawings. First Embodiment Configuration of Work Machine 100 FIG. 1 is a schematic diagram showing the configuration of a work machine 100 according to a first embodiment. The work machine 100 according to the first embodiment performs automatic excavation control in accordance with instructions from an operator. Automatic excavation control is control that automatically performs an operation of driving the boom 131, arm 132, and bucket 133 to excavate earth and sand from a state in which the cutting edge of the bucket 133 is positioned at the excavation start position above the excavation target. In other words, in automatic excavation control, the work machine 100 drives the work implement 130 without outputting operation signals to the traveling body 110 and the rotating body 120. The work machine 100 operates at a construction site, excavates earth and sand as a construction target, and loads the excavated material into a loading vessel 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 excavator. The work machine 100 includes a traveling body 110, a rotating body 120, a work implement 130, and a cab 140. Examples of objects to be loaded include a dump truck and a hopper.

[0009] 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 section. The rotating body 120 is supported on the running body 110 so that it can rotate about a rotation center. The work implement 130 is hydraulically driven. 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 boards and operates the work machine 100. The cab 140 is provided on the front left part of the rotating body 120. Here, the part of the rotating body 120 to which the work implement 130 is attached is referred to as the front part. Furthermore, with respect to the rotating body 120, the opposite part, left part, and right part are referred to as the rear, left part, and right part, respectively, based on the front part.

[0010] <Configuration of the Swing Unit 120> The swing unit 120 includes an engine 121, a hydraulic pump 122, a control valve 123, a swing motor 124, and a swing parking brake 125. 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. The swing parking brake 125 can stop the swing of the swing unit 120 by mechanical braking force. The swing parking brake 125 stops the rotation of the swing unit 120 relative to the traveling unit 110. The swing parking brake 125 may be, for example, a disc brake. The swing parking brake 125 is a hydraulic negative brake, and the brake is released by the introduction of pressurized oil from the brake solenoid valve 1253. The swing parking brake 125 is an example of a swing braking device that stops the swing of the swing unit 120.

[0011] <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.

[0012] 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 limiting, and 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 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 with its opening facing the revolving unit 120 (rearward). That is, the work machine 100 , which is a backhoe excavator, performs excavation by pulling the bucket 133 towards the front side of the rotating body 120 .

[0013] 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.

[0014] <Configuration of the Cab 140> Figure 2 is a diagram showing the internal configuration of the cab 140 according to the first embodiment. The cab 140 is provided with a driver's seat 141, an operation terminal 142, an operation device 143, and a swing lock switch 144. 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 formed, for example, of a touch panel, and may have an operation unit operated by the 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.

[0015] 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, and a start switch 143SW.

[0016] 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.

[0017] 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.

[0018] The right operating lever 143RO is an operating mechanism for performing the excavation / dumping operation of the bucket 133 and the excavation / dumping operation of the boom 131. Specifically, when the operator of the work machine 100 tilts the right operating lever 143RO forward, the excavation operation of the boom 131 is performed. Furthermore, when the operator of the work machine 100 tilts the right operating lever 143RO rearward, the dumping operation of the boom 131 is performed. Furthermore, when the operator of the work machine 100 tilts the right operating lever 143RO to the right, the dumping operation of the bucket 133 is performed. Furthermore, when the operator of the work machine 100 tilts the right operating lever 143RO to the left, the excavation operation of the bucket 133 is performed. Note that in other embodiments, when the right operating lever 143RO is tilted in the forward / backward direction, the bucket 133 may perform the dumping operation or the excavation operation, and when the right operating lever 143RO is tilted in the left / right direction, the boom 131 may perform the excavation operation or the dumping operation.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] The start switch 143SW is provided, for example, on the handle portion of the left operation lever 143LO. The start switch 143SW may be disposed so as to be located near the operator seated in the driver's seat 141. When the start switch 143SW is operated, an excavation instruction signal is output to the control device 160. When the control device 160 receives the input of the excavation instruction signal, it starts automatic excavation control.

[0023] The swing lock switch 144 is provided near the driver's seat 141. The swing lock switch 144 is an alternate switch that is manually operated by the operator to activate or release the swing parking brake 125. When the swing lock switch 144 is in the on state, the swing parking brake 125 is activated and the swing unit 120 does not swing. The swing lock switch 144 is manually switched to the on state when it is desired to keep the swing unit 120 stopped. When the swing lock switch 144 is in the off state, the swing parking brake 125 is released and the swing unit 120 is able to swing.

[0024] For example, when the swing lock switch 144 is operated by the operator to activate the swing parking brake 125, the swing parking brake 125 is activated, stopping the rotation of the rotating unit 120. When the swing parking brake 125 is activated, the rotating unit 120 does not rotate even if the left operation lever 143LO is operated to rotate the rotating unit 120. For example, when manually operating the work implement 130 without rotating the rotating unit 120, the operator operates the swing lock switch 144. When the rotating unit 120 is not rotated, there is a high possibility that the left operation lever 143LO for rotating the rotating unit 120 will be in a neutral state. When the work machine 100 is working on an inclined surface, for example, if the left operation lever 143LO is in a neutral state, the rotating unit 120 may rotate due to its own weight. By operating the swing lock switch 144, the swing parking brake 125 is activated, and the swing body 120 is prevented from swinging even when the left operating lever 143LO is in the neutral state.

[0025] <Configuration of Swing Brake> Figure 3 is a schematic diagram showing the configuration of the swing parking brake 125 according to the first embodiment. The swing parking brake 125 includes a brake cylinder 1251, a pair of brake discs 1252, and a brake solenoid valve 1253. The swing lock switch 144 is disposed between the control device 160 and the brake solenoid valve 1253. The control device 160 receives one or both of an input signal indicating that the swing lock switch 144 has been operated to activate the swing parking brake 125 and an input signal indicating that the swing lock switch 144 has been operated to release the swing parking brake 125.

[0026] The brake cylinder 1251 is a hydraulic cylinder with a spring that is driven by hydraulic oil. The brake cylinder 1251 is normally in a pushed-out state, and the rod is retracted when hydraulic oil is supplied to the rod side.

[0027] The brake disc 1252 is provided at the tip of the rod of the brake cylinder 1251. When the rod is extended, the brake disc 1252 abuts against the swing motor 124, locking the rotation of the swing motor 124. When the rod is retracted, the brake disc 1252 moves away from the swing motor 124, releasing the swing motor 124. In other words, the swing parking brake 125 is released when hydraulic oil is supplied to the oil chamber on the rod side of the brake cylinder 1251. When the brake solenoid valve 1253 is driven and the brake cylinder 1251 contracts, the pair of brake discs 1252 move apart, and the swing parking brake 125 is released. When the drive of the brake solenoid valve 1253 is stopped, the brake cylinder 1251 extends due to the elastic force of the spring provided in the brake cylinder 1251. When the brake cylinder 1251 is extended, the pair of brake discs 1252 come into contact with each other, and the swing parking brake 125 is activated.

[0028] The brake solenoid valve 1253 controls the operation and release of the swing parking brake 125. When the brake solenoid valve 1253 is switched to the on state, the brake solenoid valve 1253 is driven to open the valve position, thereby releasing the swing parking brake 125. When the brake solenoid valve 1253 is energized, it releases the swing parking brake 125, and when it is deenergized, it activates the swing parking brake 125.

[0029] The brake solenoid valve 1253 is electrically connected to the control device 160, which will be described later, via the swing lock switch 144. When the swing lock switch 144 is in the OFF state, the brake solenoid valve 1253 is always energized and releases the swing parking brake 125, thereby releasing the swing lock. When the swing lock switch 144 is in the ON state, a brake actuation signal from the control device 160 is supplied to the brake solenoid valve 1253, so that the brake solenoid valve 1253 is de-energized, the swing parking brake 125 is actuated, and swinging is not possible.

[0030] <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 , a bucket stroke sensor 155 , and a shape detection device 156 .

[0031] 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 satellites that make up the GNSS. The two receivers are installed at different positions on the revolving unit 120. The position and orientation calculator 151 detects the position of a representative point of the revolving unit 120 in the site coordinate system (the origin of the excavator 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 in which the revolving unit 120 faces as the relationship between the installation position of one receiver and the installation position of the other receiver. The orientation in which the revolving unit 120 faces is the direction perpendicular to the front of the revolving unit 120. The direction in which the rotating body 120 faces is equal to the horizontal component of the extension direction of a straight line extending from the boom 131 to the bucket 133 of the work implement 130 .

[0032] The inclinometer 152 measures the acceleration and angular velocity of the rotating unit 120, and detects the attitude (e.g., roll angle, pitch angle, yaw 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).

[0033] 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.

[0034] The shape detection device 156 detects the position and surface shape of an object present in the detection direction. Examples of the shape detection device 156 include a stereo camera and a laser scanner. The shape detection device 156 is installed, for example, so that the detection direction faces forward of the cab 140 of the work machine 100. The shape detection device 156 identifies the surface shape of the object in a coordinate system based on the position of the shape detection device 156. Note that a shape detection device 156 according to another embodiment may identify the surface shape of the object based on the vehicle body coordinate system, based on dimensional values ​​of the mounting position of the shape detection device 156 measured in advance based on the vehicle body coordinate system. Furthermore, a shape detection device 156 according to another embodiment may identify the surface shape of the object based on the on-site coordinate system, based on dimensional values ​​of the mounting position of the shape detection device 156 measured in advance based on the vehicle body coordinate system, and on position and attitude information of the vehicle in the on-site coordinate system.

[0035] <Configuration of the Control Device 160> FIG. 4 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.

[0036] 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.

[0037] 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.

[0038] By executing a program, the processor 610 is equipped with a measurement data acquisition unit 611, an operation signal input unit 612, a work machine position identification unit 613, a trajectory generation unit 614, a movement control unit 615, a turning determination unit 616, a brake control unit 617, and an operation signal output unit 618.

[0039] The measurement data acquisition unit 611 acquires, for example, the rotation speed, position, and orientation of the rotating unit 120, the tilt angles of the boom 131, arm 132, and bucket 133, the attitude of the rotating unit 120, and the surface shape of the environment of the work machine 100. Note that the surface shape of the environment of the work machine 100 includes the surface shape of the excavation target.

[0040] 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, the bucket stroke sensor 155, and the shape detection device 156. The measurement data acquisition unit 611 calculates the angle of the revolving unit 120 by integrating the angular velocity of the revolving unit 120 measured by the inclination measuring device 152.

[0041] The operation signal input unit 612 receives input of manual operation signals manually operated by the operator from the operation device 143. The manual operation signals include a drive signal for performing a dumping operation or an excavation operation on the boom 131, a drive signal for performing a dumping operation or an excavation operation on the arm 132, a drive signal for performing a dumping operation or an excavation operation on the bucket 133, a drive signal for performing a right-swing operation or a left-swing operation on the rotating unit 120, a drive signal for performing a travel operation on the traveling unit 110, and an excavation instruction signal for the work machine 100.

[0042] The work implement position identifying unit 613 identifies the position of the cutting edge of the bucket 133 in a vehicle body coordinate system that is based on the revolving unit 120, based on the measurement data acquired by the measurement data acquiring unit 611. The work implement position identifying unit 613 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 613 determines the vertical and horizontal components of the length of the arm 132. Furthermore, the work implement position identifying unit 613 determines the vertical and horizontal components from the pin of the bucket 133 to the cutting edge, based on the inclination angle of the bucket 133 and the known shape of the bucket 133. The work machine position identification unit 613 identifies 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 components and the sum of the horizontal components of the lengths of the boom 131, arm 132, and bucket 133 as the position of the cutting edge of the bucket 133.

[0043] The trajectory generating unit 614 generates a target trajectory T for the bucket 133 based on the position of the cutting edge of the bucket 133 identified by the work machine position identifying unit 613 when the excavation command signal is input and the measurement data of the shape detecting device 156. FIG. 5 is a diagram showing an example of a target trajectory according to the first embodiment. The target trajectory T for the bucket 133 is drawn as a trajectory of the cutting edge of the bucket 133 that excavates the excavation target in the excavation direction from the position of the cutting edge of the bucket 133 when the excavation command signal is input. In a backhoe excavator, the excavation direction is toward the rear of the rotating body 120. The shape of the target trajectory T according to the first embodiment is an arc. The target trajectory T is a target trajectory when excavation is performed by operating only the work machine without swinging. The target trajectory T for the bucket 133 draws an arc according to a predetermined excavation curve ratio, as shown in FIG. 5. The excavation curve ratio is a value (D / L) expressed as the ratio of the excavation depth D to the excavation length L. The smaller the excavation curve ratio, the longer the excavation length L and the shallower the excavation depth D. The larger the excavation curve ratio, the shorter the excavation length L and the deeper the excavation depth D. A method for determining the excavation curve ratio will be described later. The trajectory generation unit 614 calculates the excavation amount when excavating according to the generated target trajectory T, and generates the target trajectory T of the bucket 133 so that the excavation amount is equal to the maximum capacity of the bucket 133. Note that the shape of the target trajectory T in other embodiments may be any curve having a downward convex shape, such as an elliptical arc, a parabola, or a gentle curve without an inflection point.

[0044] The movement control unit 615 generates an automatic operation signal for moving the cutting edge of the bucket 133 along the target trajectory T when the operation signal input unit 612 receives an input of an excavation instruction signal.

[0045] The rotation determination unit 616 determines whether or not an unintended rotation by the operator is occurring based on the difference between the orientation of the revolving body 120 at the start of automatic excavation control measured by the position and orientation calculator 151 and the current orientation of the revolving body 120. For example, the orientation of the revolving body 120 refers to the attitude of the revolving body.

[0046] The brake control unit 617 switches the brake release signal supplied to the brake solenoid valve 1253 between on and off. The brake release signal is a binary signal having either an on or off value. When the value of the brake release signal is off, the swing parking brake 125 is activated, and when the value of the brake release signal is on, the swing parking brake 125 is released. The brake control unit 617 turns the value of the brake release signal off when an unintended turn by the operator occurs. When the automatic excavation control is completed, the brake control unit 617 turns the value of the brake release signal on.

[0047] The operation signal output unit 618 outputs the manual operation signal input to the operation signal input unit 612 and the automatic operation signal generated by the movement control unit 615. Specifically, the operation signal output unit 618 outputs the automatic operation signal generated by the movement control unit 615 and the brake control unit 617 when automatic excavation control is in progress, and outputs the manual operation signal input to the operation signal input unit 612 when automatic excavation control is not in progress.

[0048] <<Operation>> When the operator of the work machine 100 moves the cutting edge of the bucket 133 to the excavation start position, he or she operates the start switch 143SW. This causes the operation device 143 to generate and output an excavation command signal. The excavation start position is a position on the surface of the excavation target.

[0049] When the control device 160 receives an excavation command signal from the operator, it first generates a target trajectory T for the bucket 133. Specifically, the control device 160 generates the target trajectory T in the following procedure. First, the measurement data acquisition unit 611 acquires measurement data related to the position and orientation of the revolving unit 120, the relative angles between the boom 131, the arm 132, and the bucket 133, the attitude of the revolving unit 120, and the surface shape of the excavation target. The work implement position identification unit 613 identifies the position of the cutting edge of the bucket 133 at the time the excavation command signal was input, based on the measurement data acquired by the measurement data acquisition unit 611. The trajectory generation unit 614 generates the target trajectory T for the bucket 133 so that the target trajectory T passes through the cutting edge position identified by the work implement position identification unit 613 and so that the excavation volume is equal to the maximum capacity of the bucket 133. At this time, the swing determination unit 616 also records the orientation of the revolving unit 120 at the time the excavation command signal was input in the main memory 630.

[0050] 6 is a flowchart showing the automatic excavation control method according to the first embodiment. When the target trajectory is generated, the control device 160 executes the automatic excavation control shown in FIG.

[0051] The measurement data acquisition unit 611 acquires measurement data related to the position and orientation of the revolving unit 120, the relative angles between the boom 131, arm 132, and bucket 133, the attitude of the revolving unit 120, and the surface shape of the excavation target (step S1). The work machine position identification unit 613 identifies the position of the cutting edge of the bucket 133 at the time of input of the excavation command signal based on the measurement data acquired by the measurement data acquisition unit 611 (step S2). The movement control unit 615 determines the target position of the cutting edge of the bucket 133 and the target attitude of the bucket 133 based on the target trajectory T and the position of the cutting edge of the bucket 133 (step S3).

[0052] The movement control unit 615 determines the target positions and target attitudes of the boom 131 and the arm 132 based on the target position of the cutting edge and the target attitude of the bucket 133 (step S4). For example, the movement control unit 615 can identify the position of the tip of the boom 131, i.e., the position of the base end of the arm 132, for moving the cutting edge of the bucket 133 to the target position, based on the relationship between the position of the base end of the bucket 133 identified from the target position of the cutting edge and the target attitude of the bucket 133 and the known position of the base end of the boom 131. The movement control unit 615 generates an automatic operation signal for the work machine 130 based on the identified target positions and target attitudes of the boom 131, arm 132, and bucket 133 (step S5).

[0053] The rotation determination unit 616 calculates the angle (rotation angle) of the difference between the orientation of the rotating body 120 indicated by the measurement data obtained from the position and orientation calculator 151 in step S1 and the orientation of the rotating body 120 at the time of input of the excavation instruction signal recorded in the main memory 630 (step S6).

[0054] The turning determination unit 616 determines whether the absolute value of the calculated turning angle exceeds a predetermined turning angle threshold value (step S7). The turning angle threshold value may be set in consideration of the measurement error of the position and orientation calculator 151.

[0055] If the absolute value of the turning angle exceeds the turning angle threshold value (step S7: YES), the turning determination unit 616 determines that an unintended turning by the operator is occurring. If it is determined that an unintended turning by the operator is occurring, the brake control unit 617 switches the value of the brake release signal supplied to the brake solenoid valve 1253 to OFF (step S8). Thereafter, the brake control unit 617 maintains the value of the brake release signal at OFF until the automatic excavation control is completed.

[0056] On the other hand, if the absolute value of the turning angle does not exceed the turning angle threshold value (step S7: NO), the turning determination unit 616 determines that an unintended turning by the operator has not occurred. If it is determined that an unintended turning by the operator has not occurred, the brake control unit 617 maintains the value of the brake release signal.

[0057] Next, the operation signal output unit 618 outputs the automatic operation signal generated by the movement control unit 615 in step S5 to the control valve 123 (step S9). As a result, the work machine 130 moves along the target trajectory T.

[0058] The movement control unit 615 determines whether the position of the cutting edge of the bucket 133 is located at the end point of the target trajectory T (step S10). If the position of the cutting edge of the bucket 133 is not located at the end point of the target trajectory T (step S10: NO), the control device 160 returns the process to step S1 and determines the next target position and target attitude of the work implement 130. On the other hand, if the position of the cutting edge of the bucket 133 is located at the end point of the target trajectory T (step S10: YES), the brake control unit 617 sets the value of the brake release signal to ON (step S11). Then, the control device 160 ends the automatic excavation control.

[0059] <<Actions and Effects>> In this way, the control device 160 of the work machine 100 according to the first embodiment determines whether the revolving body 120 is revolving during automatic excavation control, and if it is determined that the revolving body 120 is revolving, activates the swing parking brake 125. Automatic excavation control is a control in which the work machine 100 does not output operation signals for the traveling body 110 and the revolving body 120, but instead drives the work implement 130. In this way, the control device 160 locks the rotation of the revolving body 120, and can prevent the revolving body 120 from revolving unintentionally by the operator.

[0060] The control device 160 according to the first embodiment uses the orientation of the revolving unit 120 indicated by the measurement data of the position and orientation calculator 151 to compare the attitude of the revolving unit 120 at the start of automatic excavation control with the attitude of the revolving unit 120 during automatic excavation control, but is not limited to this. For example, the control device 160 according to other embodiments may use an integrated value of the angular velocity of the revolving unit 120 indicated by the measurement data of the inclination measuring device 152 after the start of automatic excavation control to compare the attitude of the revolving unit 120 at the start of automatic excavation control with the attitude of the revolving unit 120 during automatic excavation control. Furthermore, the control device 160 according to other embodiments may use an integrated value of measurement values ​​of an encoder (not shown) provided on the revolving unit to compare the attitude of the revolving unit 120 at the start of automatic excavation control with the attitude of the revolving unit 120 during automatic excavation control.

[0061] Second Embodiment The control device 160 according to the first embodiment determines whether the revolving body 120 is revolving by comparing the attitude of the revolving body 120 at the start of automatic excavation control with the attitude of the revolving body 120 during automatic excavation control. In contrast, the control device 160 according to the second embodiment determines whether the revolving body 120 is revolving based on the measured value of the pressure of the hydraulic oil of the revolving motor 124 after the start of automatic excavation control.

[0062] FIG. 7 is a diagram showing the configuration of a swing motor 124 according to the second embodiment. The swing motor 124 is connected to a control valve 123. The work machine 100 according to the second embodiment is provided with a pressure gauge 157 that measures the pressure of hydraulic oil at each of the two ports of the swing motor 124. The swing direction of the swing motor 124 is determined by the position of the control valve 123. When the control valve 123 is in the neutral position, hydraulic oil is not supplied to the swing motor 124. In this case, when the swing motor 124 rotates due to external forces, the internal pressure of the two ports of the swing motor 124 changes. Therefore, the control device 160 can determine whether the swing bed 120 is swinging based on the difference between the measured values ​​of the two pressure gauges 157. As shown in FIG. 7, the hydraulic circuit is provided with check valves to prevent the internal pressures of the two ports from becoming negative, and a relief valve to prevent the internal pressure from excessively increasing due to external forces.

[0063] The swing determination unit 616 according to the second embodiment calculates the differential pressure between the ports of the swing motor 124 based on the difference in measurement data acquired from the two pressure gauges 157. The swing determination unit 616 determines that an unintended swing by the operator is occurring when the absolute value of the differential pressure between the ports of the swing motor 124 exceeds a predetermined differential pressure threshold. If it is determined that an unintended swing by the operator is occurring, the brake control unit 617 turns off the value of the brake release signal.

[0064] <<Actions and Effects>> In this way, the control device 160 of the work machine 100 according to the second embodiment determines whether or not the revolving body 120 is revolving during automatic excavation control, and if it is determined that the revolving body 120 is revolving, activates the revolving parking brake 125. In this way, the control device 160 according to the second embodiment can prevent the revolving body 120 from revolving unintentionally by the operator, similar to the first embodiment.

[0065] The control device 160 according to the second embodiment determines whether the rotating body 120 is rotating using the differential pressure between the ports of the rotation motor 124, but is not limited to this. For example, the control device 160 according to another embodiment may measure the flow rate of hydraulic oil in the rotation motor 124 and determine whether the rotating body 120 is rotating based on the flow rate. In this case, the control device 160 can identify the direction of rotation based on the flow direction of the hydraulic oil.

[0066] Third Embodiment The work machine 100 according to the first and second embodiments activates the swing parking brake 125 when an unintended turn occurs. In contrast, the work machine 100 according to the third embodiment activates the swing parking brake 125 when automatic excavation control starts, regardless of whether an unintended turn occurs or not. Therefore, the control device 160 according to the third embodiment does not need to be equipped with a swing determination unit 616.

[0067] Fig. 8 is a flowchart showing an automatic excavation control method according to the third embodiment. When the target trajectory T is generated, the control device 160 executes the automatic excavation control shown in Fig. 8. The target trajectory T is generated by the same method as the control device 160 according to the first embodiment.

[0068] When the automatic excavation control starts, the brake control unit 617 switches the value of the brake release signal supplied to the brake solenoid valve 1253 to OFF (step S21). That is, the brake control unit 617 activates the swing parking brake 125 in response to the input of the excavation instruction signal, i.e., the instruction to start automatic control. Thereafter, the brake control unit 617 maintains the value of the brake release signal at OFF until the automatic excavation control ends.

[0069] The measurement data acquisition unit 611 acquires measurement data related to the position and orientation of the revolving unit 120, the relative angles between the boom 131, arm 132, and bucket 133, the attitude of the revolving unit 120, and the surface shape of the excavation target (step S22). The work machine position identification unit 613 identifies the position of the cutting edge of the bucket 133 at the time of input of the excavation command signal based on the measurement data acquired by the measurement data acquisition unit 611 (step S23). The movement control unit 615 determines the target position of the cutting edge of the bucket 133 and the target attitude of the bucket 133 based on the target trajectory T and the position of the cutting edge of the bucket 133 (step S24).

[0070] The movement control unit 615 determines the target position and target attitude of the boom 131 and arm 132 based on the target position of the cutting edge and the target attitude of the bucket 133 (step S25). The movement control unit 615 generates an automatic operation signal for the work implement 130 based on the identified target positions and target attitudes of the boom 131, arm 132, and bucket 133 (step S26). The operation signal output unit 618 outputs the automatic operation signal generated by the movement control unit 615 to the control valve 123 (step S27). As a result, the work implement 130 moves along the target trajectory T.

[0071] The movement control unit 615 determines whether the position of the cutting edge of the bucket 133 is located at the end point of the target trajectory T (step S28). If the position of the cutting edge of the bucket 133 is not located at the end point of the target trajectory T (step S28: NO), the control device 160 returns the process to step S22 and determines the next target position and target attitude of the work implement 130. On the other hand, if the position of the cutting edge of the bucket 133 is located at the end point of the target trajectory T (step S28: YES), the brake control unit 617 sets the value of the brake release signal to ON (step S29). Then, the control device 160 ends the automatic excavation control.

[0072] <<Actions and Effects>> In this way, the control device 160 according to the third embodiment activates the swing parking brake 125 and executes automatic excavation control in response to an excavation command signal. For example, the control device 160 activates the swing parking brake 125 and executes automatic excavation control based on an excavation command signal. This enables the control device 160 to prevent unintended swings from occurring while the work machine 100 is working.

[0073] <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 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 into multiple computers that 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 installed inside the work machine, and other computers may be provided external to the work machine.

[0074] The control device 160 according to the embodiment described above automatically activates the swing parking brake 125 during automatic excavation control, but is not limited to this. For example, the control device 160 according to another embodiment may have a function of executing automatic earth removal control and may automatically activate the swing parking brake 125 during automatic earth removal control.

[0075] Furthermore, for example, the control device 160 according to another embodiment may determine whether or not an unintended rotation has occurred due to manual operation by the operator. For example, the control device 160 according to another embodiment may determine whether or not the rotating unit 120 is rotating when a manual operation signal for the work implement 130 is input and a manual operation signal for the rotating unit 120 is not input, or when a neutral signal for maintaining the attitude of the rotating unit 120 is input. In this case, the control device 160 may release the swing parking brake 125 when a manual operation signal for the rotating unit 120 is input.

[0076] The swing motor 124 of the work machine 100 according to the embodiment described above is a hydraulic motor driven by hydraulic oil, which is a working medium, but is not limited to this. For example, the swing motor 124 according to other embodiments may be an electric motor. The current flowing through an electric motor is an example of the working medium.

[0077] The work machine 100 according to the embodiment described above is a manned vehicle operated by an operator who rides on board, but is not limited to this. For example, the work machine 100 according to another embodiment may be a remotely operated vehicle that is operated by operation signals acquired via communications from a remote control device that is operated by an operator in a remote office while viewing a monitor screen. In this case, some of the functions of the control device 160 may be provided in the remote control device.

[0078] According to the above embodiment, the control system for the work machine can prevent unintentional turning from occurring while the work machine is working.

[0079] 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 125...Swing parking brake 1251...Brake cylinder 1252...Brake disc 1253...Brake solenoid valve 130...Working machine 131...Boom 131C...Boom cylinder 132...Arm 132C...Arm cylinder 133...Bucket 133C...Bucket cylinder 134...Tilt rotator 1341...Mounting portion 1342...Tilt portion 1343...Rotating portion 1344...Tilt encoder 1345...Rotate encoder 140...Driver's cab 141...Driver's seat 142...Operation terminal 143...Operation device 143LF...Left foot pedal 143LO...Left operation lever 143LT...Left travel lever 143RF...Right foot pedal 143RO...Right operation lever 143RT...Right travel lever 143SW...Start switch 144...Swing lock switch 151...Position and direction calculator 152...Inclination measuring device 153...Boom stroke sensor 154...Arm stroke sensor 155...Bucket stroke sensor 156...Shape detection device 157...Pressure gauge 160...Control device 610...Processor 611...Measurement data acquisition unit 612...Operation signal input unit 613...Work implement position identification unit 614...Trajectory generation unit 615...Movement control unit 616...Swing determination unit 617...Brake control unit 618...Operation signal output unit 630...Main memory 650...Storage 670...Interface T...Target trajectory

Claims

1. A control system for a work machine comprising: a rotating body that can rotate around a rotation center; a working machine attached to the rotating body; and a rotation braking device that stops the rotation of the rotating body, the control system for a work machine further comprising a brake control unit that activates the rotation braking device when the rotating body is not being operated and the working machine is driving.

2. A work machine control system as set forth in claim 1, further comprising a rotation determination unit that determines whether or not the rotating body is rotating when the rotating body is not being operated and the work machine is being driven.

3. A work machine control system as set forth in claim 2, wherein the turning determination unit activates the turning brake device when it is determined that the rotating body is turning.

4. A work machine control system as described in claim 2, wherein the rotation determination unit determines whether the rotating body is rotating by comparing the posture of the rotating body at the start of work by driving the work machine with the posture of the rotating body during the work.

5. A work machine control system as described in claim 2, wherein the rotation determination unit determines whether the rotating body is rotating or not based on a measurement value related to the working medium of a rotation motor that rotates the rotating body after work has started by driving the work machine.

6. A work machine control system as described in claim 1, which receives an instruction to start automatic control for driving the work machine without rotating the rotating body, and activates the swing brake device and executes the automatic control based on the start instruction.

7. A control system for a work machine according to claim 6, wherein the swing brake device is released after the automatic control is completed.

8. A control method for a work machine including a rotating body rotatable around a rotation center, a work machine attached to the rotating body, and a rotation braking device that stops the rotation of the rotating body, the control method for a work machine comprising the steps of: executing automatic control for driving the work machine without rotating the rotating body; and operating the rotation braking device while the automatic control is being executed.

9. A work machine remote control system comprising: a work machine control system as claimed in any one of claims 1 to 7; and a display device and an operating device provided remotely from the work machine control system.

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