WO2024135228A1

WO2024135228A1 - Control system and control method for work machine

Info

Publication number: WO2024135228A1
Application number: PCT/JP2023/042249
Authority: WO
Inventors: 智彦越智; 稔志中野; 諒太天草
Original assignee: コベルコ建機株式会社
Priority date: 2022-12-22
Filing date: 2023-11-24
Publication date: 2024-06-27

Abstract

Provided is a control system (60) that enables the execution of appropriate operation restriction control corresponding to a work mode while allowing sufficient recognition by an operator. This control system (60) comprises: a mode detector (62) that detects a current work mode; an object detector (64) that detects a monitored object; a notifier (68) that can notify an operator; a controller (70) that performs operation restriction control based on the detection of the monitored object; and an operation restriction control switch (66) that can be imparted with a stop operation for stopping the operation restriction control. The controller (70): causes the notifier to notify of a stop instruction for prompting a stop operation when the operation restriction control is being executed and a suspension work mode is detected; continues the operation restriction control until the stop operation is imparted to the operation restriction control switch (66); and stops the operation restriction control at the point in time at which the stop operation is imparted.

Description

CONTROL SYSTEM AND CONTROL METHOD FOR CONSTRUCTION MACHINE

The present invention relates to a control system and a control method for a work machine that has both a function for performing lifting work and a function for performing other work.

　Conventionally, there are known work machines that have both the function of performing lifting work and the function of performing other work (normal work). In addition to the function of performing the normal work, such as digging using a bucket at the end of an attachment, the work machine is also capable of performing the lifting work function by attaching a hook for lifting a load to the end of the attachment.

On the other hand, a system is known that monitors the periphery of a work machine and performs operation restriction control. Such a system generally includes a detector and a control device. The detector detects a monitoring target in the periphery of the work machine. The control device performs operation restriction control when the detector detects the monitoring target. The operation restriction control is, for example, a restriction on the operation of the work machine or a warning announcement.

When the system for motion limit control is applied to a work machine equipped with the lifting function, there are cases where the execution of the motion limit control during the lifting operation actually leads to a decrease in safety. Specifically, during the lifting operation, a load is suspended from the tip of the attachment via a wire rope or the like. If the motion limit control command is output during the lifting operation and the operation of the work machine is forcibly decelerated suddenly, or if the operator performs an emergency stop operation in response to a warning that has been issued, the load may swing significantly due to its inertia.

Patent Document 1 discloses that, in order to prevent large swaying of the suspended load due to the execution of contact avoidance control during the above-mentioned suspension operation, when the activation switch is turned off in the suspension operation mode, even if the obstacle detection sensor detects an obstacle, the operation of the vehicle body or the working device is controlled according to the amount of operation of the operating device, i.e., no operation restrictions are imposed.

However, if the operation restriction process, i.e., the operation restriction control, is automatically released when the work mode is switched from a mode other than the suspended operation mode to the suspended operation mode while the activation switch is turned off, there is a risk that the operator will not be fully aware that the operation restriction control has been released. In other words, there is a risk that the operation restriction control will be automatically released without the operator being aware of it.

JP 2021-71000 A

The present invention aims to provide a control system and a control method that enable appropriate operation restriction control to be executed according to the work mode while ensuring the operator's full awareness.

　What is provided is a control system for a work machine, the work machine having a plurality of work modes including a suspended work mode. The control system includes a mode detector, an object detector, an operation limit control switch, an alarm, and a controller. The mode detector detects a current work mode among the plurality of work modes. The object detector detects a monitored object in the vicinity of the work machine. The alarm is capable of notifying an operator. The controller is capable of performing operation limit control that limits the operation of the work machine based on the detection of the monitored object. A stop operation can be given to the operation limit control switch by an operator. The controller is configured to cause the alarm to issue a stop instruction prompting the stop operation when the operation limit control is being performed and the suspended work mode is detected, to continue the operation limit control until the stop operation is given to the operation limit control switch, and to stop the operation limit control at the time when the stop operation is given.

1 is a side view of a hydraulic excavator according to an embodiment of the present invention. FIG. FIG. 2 is a block diagram showing a control system for controlling the hydraulic excavator. FIG. 4 is a diagram showing the contents of a notification provided by the control system. 4 is a flowchart showing a flow of control executed by the control system.

Below, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a work machine 2 according to an embodiment of the present invention, and FIG. 2 shows a control system 60 for controlling the operation of the work machine 2.

The work machine 2 is a hydraulic excavator and includes a lower traveling body 10, an upper rotating body 20, a work device 30, and a drive device 40 and an operating device 50 shown in FIG. 2.

The lower running body 10 includes a running frame (not shown) and a pair of crawlers 12 arranged on the left and right sides of the frame. The pair of crawlers 12 can be driven to rotate, which allows the lower running body 10 to run on the ground.

The upper rotating body 20 is mounted on the lower running body 10 so as to be rotatable around a central axis of rotation extending in the vertical direction. Specifically, the upper rotating body 20 includes a rotating frame 22, a cab 24, and a counterweight 26. The rotating frame 22 is rotatably connected to the running frame of the lower running body 10 via a rotating bearing (not shown). The cab 24 is mounted on the rotating frame 22 and allows an operator to board the cab 24. The cab 24 includes a driver's seat on which the operator can be seated. The counterweight 26 is disposed at the rear of the rotating frame 22.

The working device 30 is a working attachment capable of performing a work operation. The working device 30 is attached to the front of the upper rotating body 20 and can rotate integrally with the upper rotating body 20 around the central axis of rotation.

The working device 30 includes a boom 34, an arm 36, and a bucket 38. The boom 34 has a base end and a tip end on the opposite side, and the base end is connected to the swivel frame 22 so that the boom 34 can rotate around a horizontal axis, i.e., can be raised and lowered. The arm 36 has a base end and a tip end on the opposite side, and the base end is connected to the tip of the boom 34 so that it can rotate around a horizontal axis. The bucket 38 is a tip attachment that constitutes the tip of the working attachment, and is connected to the tip of the arm 36 so that it can rotate around a horizontal axis, and the rotation makes it possible to perform an excavation operation (scooping operation) and an opening operation (earth removal operation) in the opposite direction. The tip attachment is not limited to the bucket 38, and may be, for example, a crusher for crushing a work object, or a lifting magnet that attracts a work object by magnetic force.

The drive device 40 drives each of the multiple movable parts of the work machine 2 to cause the multiple movable parts to perform operations for work. The drive device 40 in this embodiment drives each of the multiple movable parts hydraulically, and includes multiple hydraulic actuators corresponding to each of the multiple movable parts, and a hydraulic circuit (not shown).

The hydraulic actuators include a travel motor (not shown), a slewing motor 42, and a plurality of extendable hydraulic cylinders, i.e., a boom cylinder 44, an arm cylinder 46, and a bucket cylinder 48. Each of the travel motor and the slewing motor 42 is a hydraulic motor, the travel motor is arranged to cause the lower running body 10 to perform a travel operation, and the slewing motor 42 is connected to the upper rotating body 20 to rotate the upper rotating body 20 relative to the lower running body 10. The boom cylinder 44 is arranged so that the boom 34 rises and falls relative to the upper rotating body 20 by the extension and contraction of the boom cylinder 44. The arm cylinder 46 is arranged so that the arm 36 rotates relative to the boom 34 by the extension and contraction of the arm cylinder 46. The bucket cylinder 48 is arranged so that the bucket 38 rotates relative to the arm 36 by the extension and contraction of the bucket cylinder 48. If the end attachment itself includes a movable part, for example if the end attachment is a crusher that performs a clamping action, the multiple hydraulic actuators may further include one that moves the movable part of the end attachment.

The hydraulic circuit includes a hydraulic pump, a plurality of control valves, and a plurality of solenoid valves. The hydraulic pump is driven by an engine (not shown) that is a power source mounted on the work machine 2, and thereby draws in and discharges hydraulic oil from a tank. The plurality of control valves are arranged corresponding to the plurality of hydraulic actuators, respectively, and open and close to change the flow direction and flow rate of hydraulic oil supplied from the hydraulic pump to each of the plurality of hydraulic actuators. The plurality of solenoid valves are arranged corresponding to the plurality of control valves, respectively, and specifically, are arranged so that each of the plurality of control valves performs an opening and closing operation in response to an electrical signal input to each of the plurality of solenoid valves. Therefore, by inputting the electrical signal to each of the plurality of solenoid valves, it is possible to control the driving of the plurality of movable parts by the plurality of hydraulic actuators, i.e., to control the operation of the work machine 2.

The engine (power source) is started when a key switch 58 shown in FIG. 2 is switched on. The key switch 58 is switched on and outputs a start command signal when an operator inserts an engine key into a key cylinder and turns it to on, thereby outputting a start command signal. The start command signal is input to an engine ECU (not shown) attached to the engine, and is also input to the control system 60.

The drive device 40 is not limited to one that moves all of the multiple movable parts hydraulically. For example, the drive device 40 may include multiple electric actuators instead of some or all of the multiple hydraulic actuators and the hydraulic circuit, and an electric circuit that controls the multiple electric actuators.

The work machine 2 has a plurality of work modes. Specifically, the work machine 2 has both a normal mode and a crane mode equivalent to a lifting work mode. In the normal mode, the work machine 2 performs an operation for performing the original work using the bucket 38, which is the tip attachment, specifically, normal work including excavation work, soil removal work, leveling work, etc. In the crane mode, the work machine 2 performs an operation for performing a lifting work using the work device 30. Specifically, a lifting tool (lifting hook) 52 can be detachably attached to a movable part (the tip of the arm 36 in the example shown in FIG. 1) that can be moved by the drive device 40 in the work device 30, and a load 56 is suspended from the lifting tool 52 via a wire rope 54 shown in FIG. 5, for example, to perform the lifting work using the work device 30.

The operating device 50 includes a plurality of operating members corresponding to the plurality of movable parts, and an operator can apply a work operation to each of the plurality of operating members. Each of the plurality of operating members is, for example, an operating lever or an operating pedal. In this embodiment, the work operations applied to each of the plurality of work members are a rotation operation for rotating the upper rotating body 20, a boom operation for raising and lowering the boom 34, an arm operation for rotating the arm 36, and a bucket operation for rotating the bucket 38. If the drive device 40 includes an attachment that moves a movable part of the tip attachment, the work operation may include a tip attachment operation for moving the movable part.

The operating device 50 generates and outputs an operating signal corresponding to the work operation applied to each of the multiple operating members. In this embodiment, the operating signal is an electrical signal. Alternatively, the operating signal may be a hydraulic signal. For example, when the drive device 40 includes the hydraulic circuit, which includes multiple remote control valves and which are connected to the multiple control valves so as to change the pilot pressure input to the multiple control valves, an operating lever or operating pedal included in each of the multiple remote control valves corresponds to the operating member, and the pilot pressure corresponds to the operating signal.

The location where the operating device 50 is disposed is not limited. The operating device 50 may be disposed in the cab 24 so that it can be operated by an operator seated in the driver's seat, or may be disposed outside the work machine 2, for example, in a remote control room.

The control system 60 has a function for controlling the operation of the work machine 2, and includes a number of elements for implementing this function, as shown in FIG. 2, namely, a lifting gear attachment detector 62, a lifting load detector 63, an object detector 64, an operation limit control switch 66, a lock operation detector 67, an alarm 68, and a controller 70.

The sling attachment detector 62 detects whether the sling 52 is attached to the work device 30. The sling attachment detector 62 may be a contact sensor that is switched from off to on by contacting the sling 52, or a non-contact sensor (e.g., an optical sensor or an ultrasonic sensor) that detects that the sling 52 is in a specified attachment position without contacting the sling 52.

The hoisting equipment attachment detector 62 constitutes a mode detector that detects the current work mode of the work machine 2. More specifically, the mode detector detects the currently employed work mode among the plurality of work modes, in other words, detects which of the plurality of work modes the current work mode of the work machine 2 is.

The lifting load detector 63 is composed of a load sensor, and detects the lifting load acting on the lifting tool 52 when the lifting tool 52 is attached to the tip of the working device 30. When the lifting load detected by the lifting load detector 63 is zero or a very small value very close to zero, it is possible to determine that the lifting work by the working device 30 has not yet actually been performed. In this way, the lifting load detector 63 can function as a lifting work detector that detects whether or not the lifting work is being performed by the working device 30. The lifting work detector may alternatively be a switch that switches on when a certain amount of lifting load or more acts on the lifting tool 52, or may be an image recognition device that recognizes the presence or absence of the load 56.

The object detector 64 detects a monitoring target in the vicinity of the work machine 2. Specifically, the object detector 64 detects the presence of a person or an obstacle in a monitoring area set around the work machine 2. The specific configuration of the object detector 64 is not limited. Preferred examples of the object detector 64 include a device that acquires two-dimensional information (e.g., position and shape in an image) of an imaged object, a camera that generates two-dimensional information (monocular camera), a device that acquires a distance image, a device that generates three-dimensional information (e.g., three-dimensional coordinates and three-dimensional shape) of an imaged object based on a distance image, a device that generates three-dimensional information using laser light, such as a LIDAR (Light Detection and Ranging) or TOF (Time Of Flight) sensor, a device that detects three-dimensional information using radio waves (e.g., millimeter wave radar), and a stereo camera.

The object detector 64 is preferably disposed at a position where it is possible to monitor the rear of the operator, for example, at the rear end of the upper rotating body 20. In addition to or instead of the rear end, the object detector 64 may be disposed at least on one of the left and right sides of the upper rotating body 20. Alternatively, the object detector 64 may be disposed at a position away from the work machine 2 at the site where work is performed by the work machine 2 so as to monitor the work machine 2 and its surrounding conditions.

The operation restriction control switch 66 is configured so that an operator can apply a stop operation and a stop release operation to the operation restriction control switch 66. The stop operation is an operation for stopping the execution of the operation restriction control by the controller 70, i.e., an operation for instructing the controller 70 to stop the operation restriction control, and the operation restriction control is a control that limits the operation of the work machine 2 based on the detection of a monitored object by the object detector 64, as will be described in detail later. The stop release operation is an operation for releasing the stop of the operation restriction control, i.e., an operation for causing the controller 70 to resume the operation restriction control.

As with the operating device 50, the location of the operation limit control switch 66 is not limited. The operation limit control switch 66 may be located at a position where the stop operation and the stop release operation are performed by an operator seated in the driver's seat, or may be provided in the remote control room together with the operating device 50. Alternatively, the operation limit control switch 66 may be attached to any one of the multiple operating members included in the operating device 50.

The operation restriction control switch 66 may be any switch that allows the stop operation and the stop release operation to be performed by an operator, and there are no limitations on its specific configuration. The operation restriction control switch 66 may be a switch that receives physical operation by the operator, such as a push switch, lever switch, or slide switch, or may be a display having a display screen capable of displaying a touch panel operated by the operator. The display screen may be a mobile screen carried by the operator.

The lock operation detector 67 detects a lock operation applied to the work machine 2 by an operator, and the lock operation is an operation for disabling the work operation applied to the operating device 50 in order to operate the work machine 2. The work machine 2 is further equipped with an operation lock device, and the lock operation detector 67 inputs a lock operation detection signal to each of the operation lock device and the controller 70 when it detects the lock operation. The operation lock device performs an operation lock operation to disable the work operation when the lock operation detection signal is input.

The lock operation detector 67 may be an operation switch that is directly operated by the operator (lock operation) like the operating device 50, or it may be a lock operation detection switch that is turned on and off in conjunction with the movement of another lock operation member for receiving the lock operation, for example, a lock lever operated to open and close the boarding/alighting door. The lock lever is switched between an open position that opens the boarding/alighting door to allow the operator to board and alight, and a closed position that blocks the boarding/alighting door to prevent the operator from boarding or alighting, and when the lock lever is in the open position, the lock operation detection switch is switched to an on state, that is, a state in which a lock command is output.

When the drive device 40 includes a hydraulic circuit and the operating device 50 includes the remote control valves corresponding to the movable parts, it is preferable that the operation lock device includes a lock valve arranged in a pilot pressure supply oil passage between the remote control valves and a pilot hydraulic source. The lock valve can collectively disable the work operations applied to the remote control valves, specifically, disable each of the remote control valves from outputting a pilot pressure corresponding to the work operation, with a simple configuration of just blocking the pilot pressure supply oil passage. In this case, the operation lock device may be configured to be directly linked to the lock operation so that the lock valve is closed, or the controller 70 or a lock control device other than the controller 70, which receives a lock operation detection signal from the lock operation detector 67, may input a command signal to the lock valve to close the lock valve. In other words, the controller 70 may constitute a part of the operation lock device.

The alarm 68 issues a notification to the operator as specified by the controller 70. As with the operation device 50 and the operation limit control switch 66, there are no limitations on where the alarm 68 is placed. The location may be any location that allows the alarm 68 to notify the operator, and may be close to the driver's seat or may be provided in the remote control room together with the operation device 50 and the operation limit control switch 66. Alternatively, the alarm 68 may be provided on a mobile device carried by the operator.

The notification performed by the alarm 68 may be recognized by the operator's sight or hearing. Specifically, the alarm 68 may be a display that displays the content of the notification on a screen, or a speaker that outputs the content of the notification as sound. The display may also display a touch panel including the operation limit control switch 66 on the screen. In other words, the operation limit control switch 66 and the alarm 68 may be configured by a single display.

In this embodiment, the controller 70 is a processor that controls the operation of the work machine 2 and the alarm by the alarm 68 based on information input from the operation device 50, the lifting equipment attachment detector 62, the lifting load detector 63, the object detector 64, the operation limit control switch 66, and the key switch 58, and preferably includes a computer equipped with the memory unit and the calculation unit. The controller 70 may be mounted on the work machine 2, like the operation device 50, or may be installed outside the work machine 2. The controller 70 may be included in a cloud server, for example.

The controller 70 has a mode determination unit 72, a drive control unit 74, and a notification control unit 76 shown in FIG. 2 as its main functions for executing the control, and these functions are realized by the calculation unit executing the programs stored in the storage unit. The programs include a control program for performing the operation restriction control.

The mode determination unit 72 determines the current work mode of the work machine 2 based on the presence or absence of a detection signal input from the hoisting gear attachment detector 62, i.e., based on the presence or absence of the hoisting gear 52 attached to the tip of the work device 30. Specifically, when the attachment of the hoisting gear 52 is detected, the mode determination unit 72 determines that the work mode is the crane mode, and when the attachment of the hoisting gear 52 is not detected, the mode determination unit 72 determines that the work mode is a mode other than the crane mode, which is the normal mode in this embodiment.

In this way, the sling attachment detector 62 functions as a mode detector that acquires information for identifying the current work mode. The mode detector may alternatively be a mode selection switch. The mode selection switch is operated by an operator to select the work mode, and inputs a signal designating the selected work mode to the controller 70. The mode selection switch is capable of inputting information that directly identifies the work mode to the controller 70.

The drive control unit 74 controls the drive of the work machine 2 by the drive device 40, thereby performing the following control over the operation of the work machine 2.

A. Basic Control The drive control unit 74 according to this embodiment controls driving by the drive control unit 74 so as to cause the multiple movable parts to perform an operation corresponding to the operation signal, i.e., an operation corresponding to the work operation, based on an operation signal (electrical signal) input from the operation device 50. Specifically, the drive control unit 74 generates a command signal corresponding to the work operation, and inputs the command signal to a solenoid valve corresponding to the work operation among the multiple solenoid valves included in the drive device 40, to operate a hydraulic actuator corresponding to the work operation.

The drive control unit 74 may change the control content depending on the work mode. For example, when the crane mode is detected, the drive control unit 74 may execute control to reduce the speed of driving the work device 30 by the drive device 40 or the speed of the rotation drive of the upper rotating body 20 compared to the normal mode in order to suppress swaying of the suspended load 56.

If the operating device 50 includes the multiple remote control valves and operation signals (pilot pressure) are input directly from the multiple remote control valves to each of the multiple control valves, there is no need for the drive control unit 74 to execute the basic control.

B. Operation Limit Control The drive control section 74 executes the operation limit control until the stop operation is applied to the operation limit control switch 66. As described above, the operation limit control is control for limiting the operation of the work machine based on the detection of the monitored object by the object detector 64. More specifically, when the object detector 64 detects a monitored object (person or obstacle) entering a monitoring area set around the work machine 2, the drive control section 74 performs control for decelerating the operation of the movable part of the work machine 2 so as to prevent the monitored object from coming into contact with or approaching the movable part. This deceleration also includes a sudden stop of the movable part.

In this embodiment, the deceleration is performed by changing the command signal input to the solenoid valve among the plurality of solenoid valves that corresponds to the movable part to be decelerated (i.e., by reducing the pilot pressure). Even in an embodiment in which the operating device 50 includes the plurality of remote control valves and the drive control unit 74 does not execute the basic control, the target movable part can be decelerated in the same manner as described above by inputting a pressure reduction command signal to a solenoid valve interposed between the plurality of remote control valves and the plurality of control valves.

The restriction on the operation of the work machine 2 is not limited to a direct restriction, but also includes an indirect restriction. For example, the "operation restriction control" according to the present invention also includes a restriction on the operation of the work machine 2 as a result of issuing a warning to the operator and encouraging the operator to perform an operation that suppresses the operation of the work machine 2. The warning may be issued using the alarm 68, or may be issued using an alarm other than the alarm 68.

The drive control unit 74 is configured to automatically start executing the operation restriction control based on the detection of the monitored object by the object detector 64 when the engine, which is the power source, is stopped and the key switch 58 is turned on to start the engine. The automatic start of the operation restriction control reliably prevents the occurrence of a situation in which the operation restriction control is not performed without the operator's knowledge after the engine is started.

The notification control unit 76 executes notification control. The notification control is a control that generates an appropriate notification command signal and inputs it to the annunciator 68, thereby causing the annunciator 68 to issue a notification corresponding to the notification command signal. Specifically, it is as follows.

C. Stop instruction notification control The notification control unit 76 causes the alarm 68 to issue a stop instruction when the operation limit control is being executed and the mode determination unit 72 determines that the current work mode is the crane mode. The stop instruction is an instruction to prompt the operator to apply the stop operation to the operation limit control switch 66 to stop the operation limit control, and is, for example, a display of a message saying "Please stop the operation limit control while working in the crane mode."

The stop instruction, by prompting the operator to perform the stop operation, which is an operation for halting the motion restriction control, effectively prevents the suspended load from swinging significantly due to the motion restriction control being executed during lifting work in the crane mode, restricting the motion of the work machine. The stop instruction is also effective when the restriction on the motion of the work machine is an indirect restriction, that is, when it is a warning to the operator as described above. This is because it effectively prevents a situation in which the suspended load 56 swings due to the operator receiving the warning during lifting work manually suddenly slowing down the motion of the work machine 2.

In this way, the operation restriction control is not stopped automatically by the controller 70 regardless of the operator's intention, but is only stopped when the operator, who has received the stop instruction from the alarm 68, actually performs the stop operation on the operation restriction control switch 66. Therefore, the stop of the operation restriction control can be recognized reliably by the operator.

D. Additional Notification Control When the execution of the hoisting work is further detected after the notification of the stop instruction, in this embodiment, when the hoisting load detected by the hoisting load detector 63 becomes equal to or greater than a certain level, the notification control unit 76 causes the annunciator 68 to make an additional notification of the stop instruction. This more reliably prevents the hoisting work from being continued without the motion limit control being stopped. The additional notification may be a notification made again after the first notification of the stop instruction is temporarily stopped, or a notification made to reinforce the stop instruction while the stop instruction is continuing. The former additional notification, i.e., a re-notification, may have the same content as the first notification of the stop instruction, or may have a different content. The latter notification, i.e., a reinforcing notification, may be a notification made over and above the first notification, or may emphasize the first notification, for example, an increase in the light intensity, blinking, or color change of the characters displaying the stop instruction or the surrounding parts, or an increase in the volume of the sound corresponding to the stop instruction.

The notification control unit 76 is configured to stop the notification of the stop instruction by the annunciator 68 when the locking operation is detected by the locking operation detector 67, regardless of whether the work mode is the crane mode (suspension work mode) or the normal mode (a mode other than the suspension work mode), and to cause the annunciator 68 to notify the stop instruction when the crane mode is detected and the locking operation is no longer detected while the operation restriction control is continuing. Stopping the notification of the stop instruction when the locking operation is detected prevents the stop instruction from being unnecessarily notified even when the work operation is disabled by the locking operation, that is, when the operation of the work machine 2, including the operation for the suspension work, is forcibly stopped. In addition, the notification of the stop instruction when the locking operation is released effectively prevents the operation restriction control from being executed while the crane mode is in operation when the work operation is enabled due to the release.

As described above, the drive control unit 74 automatically starts the operation restriction control when the key switch 58 is turned on to start the engine after the engine has stopped, but if the work mode detected when the engine is started is the crane mode, the notification control unit 76 is configured to cause the annunciator 68 to notify the stop command. This effectively prevents the operation restriction control that is automatically started when the engine is started from continuing in the crane mode.

E. Stop state notification control When the operation limit control is stopped even though the operation mode is an operation mode other than the crane mode, i.e., the normal mode, the notification control unit 76 is configured to cause the annunciator 68 to issue a notification for notifying the operator that the operation limit control is in a stopped state, i.e., a stopped state notification. The stopped state notification is, for example, a display of a message saying "Operation limit control is stopped, please drive while paying attention to your surroundings." In addition to such a notification about the stopped state, a notification may be issued to prompt the operator to perform a stop release operation on the operation limit control switch 66.

The notification of the stopped state ensures that the operator is aware that the motion limit control is stopped in the normal mode, which is a work mode other than the crane mode, and alerts him/her to this, thereby ensuring a high level of safety even in the normal mode.

3 shows a preferred example of the notification provided by the notification control unit 76 described above. In this example, the alarm 68 has both a display and a speaker, and in addition to the message being continuously flashed on the display, an alarm sound is intermittently emitted a predetermined number of times (e.g., five times) from the speaker. For example, when the work mode is switched from the normal mode to the crane mode while the motion restriction control is being executed (first column in the figure), a message "Stop motion restriction control while working in crane mode" is continuously flashed as the stop instruction notification, and the alarm sound is intermittently emitted the predetermined number of times. After that, when the execution of actual lifting work is detected, in this embodiment, when the lifting load detected by the lifting load detector 63 becomes equal to or greater than a certain value (second column in the figure), the alarm sound is again intermittently emitted a predetermined number of times (e.g., five times) as the additional notification while the message continues. This alarm sound is not limited to an intermittent sound, and may be, for example, a continuous sound that continues for a certain period of time.

Next, the flow of the operation restriction control performed by the controller 70 will be explained with reference to the flowchart in FIG. 4.

When the key switch 58 is turned on, i.e., when the engine starts (YES in step S10), the drive control section 74 of the controller 70 automatically starts operation restriction control regardless of the work mode (step S12). After that, the following control is executed until the key switch 58 is turned off (NO in step S42).

The controller 70 determines whether or not a lock operation has been applied to the operation lock device (step S14). If the lock operation has been applied (YES in step S14), that is, if the operation lock device has been activated to disable the operator's work operation, the operation of the work machine 2, including the operation for lifting work, is impossible and the continuation of the operation restriction control has no effect on safety, so the notification control unit 76 of the controller 70 stops all notifications by the alarm 68 (step S16).

If the lock operation is not performed or is released (NO in step S14), the controller 70 stops and releases the operation restriction control in response to the operation applied to the operation restriction control switch 66, and executes/stops the operation restriction control and issues a notification in response to the detected work mode (steps S20 to S40). As described above, these controls continue until the key switch 58 is switched off (NO in step S42).

Specifically, the drive control unit 74 of the controller 70 continues the motion restriction control (step S22) until the stop operation is given to the motion restriction control switch 66 (NO in step S20). On the other hand, the mode determination unit 72 of the controller 70 determines whether the current work mode is a crane mode (suspension work mode) or a normal mode (work mode other than the suspension work mode) based on whether the suspension equipment attachment detector 62 detects the attachment of the suspension equipment 52 (step S24). If it is the crane mode (YES in step S24), the notification control unit 76 causes the alarm 68 to issue a stop instruction to prompt the operator to perform a stop operation, which is an operation for stopping the motion restriction control (step S26). After that, if the execution of actual suspension work is further detected (YES in step S28), the notification control unit 76 causes the alarm 68 to issue an additional notification (step S30).

Even if the operation restriction control is being executed, if the work mode is not the crane mode (in this embodiment, if it is the normal mode; NO in step S24), neither the stop instruction notification nor the additional notification is issued.

Then, when the operator who has received the stop instruction notification actually performs the stop operation on the operation limit control switch 66 (YES in step S20), the drive control unit 74 stops the operation limit control (step S32). In other words, the drive control unit 74 continues the operation limit control until the stop operation is performed on the operation limit control switch 66, regardless of the work mode (NO in step S20 and step S22). This reliably prevents the operation limit control from being stopped without the operator's full awareness.

When the operation limit control is stopped, if the work mode is not the crane mode (in this embodiment, if it is the normal mode; NO in step S34), the notification control unit 76 causes the annunciator 68 to issue a stop state notification to inform the operator that the operation limit control is stopped (step S36). The stop of the operation limit control (step S32) and the stop state notification (step S36) are continued until a stop release operation is applied to the operation limit control switch 66 (NO in step S38), and when the stop release operation is applied to the operation limit control switch 66 (YES in step S38), the drive control unit 74 resumes the operation limit control (step S40).

The above-described control ends when the key switch 58 is turned off (YES in step S42).

The present invention is not limited to the above-described embodiments and modifications, but includes, for example, the following aspects:

The operation limit control switch 66 may be configured to receive only the stop operation out of the stop operation and the stop release operation. For example, after the operation limit control is stopped by the stop operation, the drive control unit 74 may be configured to automatically resume the operation limit control when the work mode is switched from the crane mode (suspension operation mode) to the normal mode (mode other than the suspension operation mode). However, if the operation limit control switch 66 can receive the stop release operation in addition to the stop operation as in the above embodiment, and the drive control unit 74 is configured to resume the operation limit control on the condition of the stop release operation, the operator can be sure to recognize not only the stop of the operation limit control but also the resumption of the operation limit control after the stop.

The multiple work modes need only include at least a lifting work mode (the crane mode in the embodiment), and work modes other than the lifting work mode are not limited. Work modes other than the lifting work mode may include modes corresponding to work other than work using the bucket 38, for example work using another end attachment (such as a crusher) that is replaced with the bucket 38.

In addition, the control system can be widely applied to work machines other than hydraulic excavators that are at least capable of performing lifting operations.

As described above, a control system is provided that enables appropriate operation restriction control to be performed according to the work mode while the operator is fully aware of the operation.

The controller in the control system, when the motion limit control is being executed and the suspension operation mode is detected, issues the stop command via the alarm to prompt the operator to perform the stop operation to stop the motion limit control, thereby effectively preventing large swaying of the suspended load caused by the motion limit control being executed during suspension operation in the suspension operation mode, i.e., the operation of the work machine being restricted. Furthermore, the controller continues the motion limit control until the stop operation is applied to the motion limit control switch, and stops the motion limit control only when the operator actually applies the stop operation to the motion limit control switch, making it possible for the operator to reliably recognize the stop of the motion limit control.

The controller is preferably configured to stop the operation limit control only when the stop operation is applied to the operation limit control switch. This makes it more certain that the operator recognizes that the operation limit control has been stopped.

The motion restriction control preferably includes control for slowing down (including sudden stops) the motion of the work machine. This control makes it possible to more reliably prevent the work machine from coming into contact with or approaching the monitoring target detected by the target detector, while the notification of the stop instruction effectively prevents the suspended load from swinging significantly due to the deceleration of the motion of the work machine. Alternatively, the motion restriction control may be control for indirectly restricting the motion of the work machine, for example, control for issuing a warning to the operator to prompt the operator to perform an operation to suppress the motion of the work machine.

The control system preferably further comprises a lifting operation detector that detects the execution of lifting operation by the work machine, and the controller is configured to cause the alarm to issue an additional notification of the stop instruction when the lifting operation detector detects the execution of the lifting operation after the notification of the stop instruction. This more reliably prevents the lifting operation from being continued without the operation restriction control being stopped. The additional notification may be a notification issued again after the notification of the stop instruction has been temporarily stopped, or may be a notification issued to reinforce the stop instruction while it is still in progress. The content of the additional notification may be the same as or different from the content at the time of the notification of the stop instruction.

The control system may further include a lock operation detector for detecting a lock operation. The lock operation is an operation for invalidating the work operation by the operator to operate the work machine. In this case, it is preferable that the controller is configured to stop the notification of the stop instruction by the alarm when the lock operation is detected regardless of the work mode, and to cause the alarm to issue the stop instruction when the lock operation is not detected and the operation restriction control is being executed and the suspension work mode is detected. The suspension of the notification of the stop instruction prevents the stop instruction for stopping the operation restriction control from being issued unnecessarily even though the work operation is invalidated by the lock operation and the work machine is not operating. On the other hand, the notification of the stop instruction when the lock operation is no longer detected effectively prevents the operation restriction control from continuing in the suspension work mode after the lock operation is released.

If the work machine is equipped with a power source, the controller may be configured to automatically execute the operation limit control when the power source is started. This makes it possible to reliably perform the operation limit control after the power source is started. In this case, the controller can effectively prevent the suspension work from being performed after the operation limit control is automatically started by having the alarm issue the stop command when the work mode is the suspension work mode at the time the power source is started.

In this aspect, if the control system further includes the lock operation detector, the controller may be configured to cause the alarm to issue the stop command only when the operation mode is the hoisting operation mode at the time the power source is started and the lock operation is not detected.

It is preferable that the operation restriction control switch can be given a stop operation as well as a stop release operation, and the controller is configured to resume the operation restriction control only when the stop release operation is given while the operation restriction control is stopped. This makes it possible for an operator to reliably recognize not only the stop of the operation restriction control but also the resumption of the operation restriction control after the stop.

The controller is preferably configured to cause the alarm to notify the operator that the motion limit control has been stopped when the work mode is a work mode other than the suspended work mode and the motion limit control has been stopped. This allows the operator to be sure that the motion limit control has been stopped even when the work mode is a work mode other than the suspended work mode, thereby ensuring high safety even in work modes other than the suspended work mode.

Also, a control method for a work machine having a plurality of work modes including a suspended work mode is provided. The method includes: performing motion limiting control that limits the operation of the work machine based on the detection of a monitored object until a stop operation is given to a motion limiting control switch by an operator; stopping the motion limiting control when the stop operation is given to the motion limiting control switch; and causing an alarm to issue a stop instruction to prompt the stop operation when the motion limiting control is being performed and the suspended work mode is detected.

Also, a control program is provided for executing operation restriction control that restricts the operation of a work machine having a plurality of work modes including a suspended work mode. The control program, when read by a computer, causes the computer to execute the operation restriction control based on the detection of a monitored object until a stop operation is given to an operation restriction control switch by an operator, to stop the operation restriction control when the stop operation is given to the operation restriction control switch, and to cause an alarm to issue a stop instruction to prompt the stop operation when the operation restriction control is being executed and the suspended work mode is detected.

Also provided is a recording medium on which the control program is recorded, the recording medium allowing the control program to be read by the computer.

Claims

1. A control system for a work machine having a plurality of work modes including a suspended work mode, comprising:
a mode detector for detecting a current operation mode among the plurality of operation modes;
an object detector that detects a monitoring object in the vicinity of the work machine;
an alarm capable of notifying an operator;
a controller capable of performing operation limiting control that limits the operation of the work machine based on detection of the monitored object;
an operation limit control switch that can be operated by an operator to stop the operation;
The controller is configured to cause the alarm to issue a stop instruction to prompt the stop operation when the operation restriction control is being executed and the suspension operation mode is detected, to continue the operation restriction control until the stop operation is applied to the operation restriction control switch, and to stop the operation restriction control at the point in time when the stop operation is applied.
The control system according to claim 1, wherein the controller is configured to stop the operation limit control only when the stop operation is applied to the operation limit control switch.
The control system according to claim 1, wherein the operation limiting control performed by the controller includes control for slowing down the operation of the work machine.
The control system according to claim 1, further comprising a lifting operation detector that detects the execution of lifting operation by the work machine, and the controller is configured to cause the alarm to issue an additional notification of the stop instruction when the lifting operation detector detects the execution of the lifting operation after the notification of the stop instruction.
The control system according to claim 1 further includes a lock operation detector that detects a lock operation, the lock operation being an operation for invalidating a work operation by an operator to operate the work machine, and the controller is configured to stop the alarm from announcing the stop instruction regardless of the work mode when the lock operation is detected, and to cause the alarm to issue the stop instruction when the lock operation is not detected and the operation limit control is being executed and the hoisting work mode is detected.
The control system according to claim 1, wherein the work machine is equipped with a power source, and the controller is configured to automatically execute the operation limit control when the power source is started, and to cause the alarm to issue the stop command when the work mode is the hoisting work mode at the time the power source is started.
The control system according to claim 5, wherein the work machine is equipped with a power source, and the controller is configured to automatically execute the operation limit control when the power source is started, and to cause the alarm to issue the stop command only when the work mode is the hoisting work mode at the time when the power source is started and the lock operation is not detected.
The control system according to claim 1, wherein the operation restriction control switch can be given a stop release operation in addition to the stop operation, and the controller is configured to resume the operation restriction control only when the stop release operation is given while the operation restriction control is stopped.
A control system according to any one of claims 1 to 8, wherein the controller is configured to cause the alarm to notify the user that the motion limit control has stopped when the work mode is a work mode other than the hoisting work mode and the motion limit control has stopped.
1. A control method for a work machine having a plurality of work modes including a suspended work mode, comprising:
performing an operation limit control to limit the operation of the work machine based on detection of a monitored object until a stop operation is given to an operation limit control switch by an operator;
stopping the operation limit control by applying the stop operation to the operation limit control switch;
and causing an alarm to issue a stop instruction to prompt the user to perform the stopping operation when the operation limiting control is being executed and the suspension operation mode is detected.
A control program for executing an operation limiting control for limiting the operation of a work machine having a plurality of work modes including a hoisting work mode, the control program being read by a computer and comprising:
performing the operation limit control based on detection of a monitored object until a stop operation is given to an operation limit control switch by an operator;
stopping the operation limit control by applying the stop operation to the operation limit control switch;
and when the operation limiting control is being executed and the suspension operation mode is detected, causing an alarm to issue a stop instruction to prompt the user to stop the operation.
12. A recording medium having the control program according to claim 11 recorded thereon, the recording medium allowing the control program to be read by the computer.