CONTROL SYSTEM AND CONTROL METHOD FOR WORK MACHINE

Abstract

A control system enables an appropriate motion restriction control according to a work mode with a sufficient recognition by an operator. The control system includes: a mode detector that detects a current work mode; an object detector that detects a monitoring object; a notifier capable of notifying an operator; a controller that performs a motion restriction control based on the detection of the monitored object; and a motion restriction control switch allowing a stop operation for stopping the motion restriction control to be applied thereto. The controller performs: making the notification device notify a stop instruction that prompts the stop operation when a suspension work mode is detected during the execution of the motion restriction control; continuing the motion restriction control until application of the stop operation to the motion restriction control switch; and stopping the motion restriction control upon the application of the stop operation.

Description

TECHNICAL FIELD

The present invention relates to a control system and a control method for a work machine having a function of performing suspension work and a function of performing other work.

BACKGROUND ART

Conventionally known is a work machine having a function of performing suspension work and a function of performing other work (normal work). The work machine is able to exhibit the function of performing the normal work such as excavation by use of a bucket at the tip of an attachment, and further enabled to exhibit the suspension work function by attachment of a hook to the tip of the attachment for load suspension.

Meanwhile is also known a system that monitors the periphery of a work machine and performs motion restriction control. The system generally includes a detector and a control device. The detector detects a monitoring object around the work machine. The control device performs the motion restriction control when the detector detects the monitoring object. The motion restriction control is, for example, restricting the motion of the work machine and/or giving a warning.

In the case of applying a system for the motion restriction control to the work machine, the execution of the suspension work function during the suspension work rather may involve deterioration of safety. Specifically, during the suspension work, in which the suspended load is suspended from the tip of the attachment through a wire rope or the like, the output of a motion restriction control command to forcibly decelerate the motion of the work machine or an operation performed by an operator for rapid deceleration in response to the given warning may cause the suspended load to be swung greatly due to the inertia thereof.

To prevent a suspended load from being thus swung due to the execution of a contact avoidance control during the above-described suspension work, Patent Literature 1 discloses, keeping the control of the motion of a machine body or a work device according to the operation amount applied to the operation device, that is, performing no motion restriction, when a validation switch is turned off in the suspension work mode, even when an obstacle detection sensor detects an obstacle.

However, the automatic release of the motion restriction processing, i.e., the motion restriction control, upon the switch of the operation mode to the suspension work mode from a mode other than the suspension work mode with the validation switch kept turned off may disable an operator from sufficiently recognizing the release of the motion restriction control. In other words, it generates a possibility of the automatic release of the motion restriction control with no recognition by the operator.

CITATION LIST

Patent Literature

Patent Literature 1: Japanese Unexamined Patent Publication No. 2021-71000

SUMMARY OF INVENTION

It is an object of the present invention to provide a control system and a control method that enable appropriate motion restriction control to be executed according to a work mode while sufficiently recognized by an operator.

Provided is a control system for a work machine, which has a plurality of work modes including a suspension work mode. The control system includes a mode detector, an object detector, a motion restriction control switch, a notification device, and a controller. The mode detector detects a current work mode among the plurality of work modes. The object detector detects a monitoring object around the work machine. The notification device is capable of performing notification to an operator. The controller is capable of performing a motion restriction control for restricting a motion of the work machine based on the detection of the monitoring object. The motion restriction control switch allows a stop operation to be applied to the motion restriction control switch by an operator. The controller is configured to perform making the notification device notify a stop instruction that prompts the stop operation when the suspension work mode is detected during execution of the motion restriction control, continuing the motion restriction control until application of the stop operation to the motion restriction control switch and stopping the motion restriction control upon the application of the stop operation.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side view of a hydraulic excavator according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a control system for controlling the hydraulic excavator.

FIG. 3 is a diagram showing the content of the notification provided by the control system.

FIG. 4 is a flowchart showing the flow of the control executed by the control system.

DESCRIPTION OF EMBODIMENT

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

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

The work machine 2 is a hydraulic excavator, including a lower traveling body 10, an upper turning body 20, a work device 30, and a drive device 40 and an operation device 50 which are shown in FIG. 2.

The lower traveling body 10 includes a non-illustrated traveling frame and a pair of crawlers 12 disposed on the left and right sides of the traveling frame. The pair of crawlers 12 can be driven roundly to thereby enable the lower traveling body 10 to travel on the ground.

The upper turning body 20 is mounted on the lower traveling body 10 capably of turning around a turning center axis extending vertically. Specifically, the upper turning body 20 includes a turning frame 22, a cab 24 and a counterweight 26. The turning frame 22 is connected to the traveling frame of the lower traveling body 10 through a non-illustrated turning bearing capably of turning. The cab 24 is mounted on the turning frame 22 to allow an operator to get on the cab 24. The cab 24 includes an operation seat that allows an operator to sit thereon. The counterweight 26 is disposed at the rear part of the turning frame 22.

The work device 30 is a work attachment capable of performing a work motion. The work device 30 is attached to the front part of the upper turning body 20 capably of turning around the turning center axis integrally with the upper turning body 20.

The work device 30 includes a boom 34, an arm 36 and a bucket 38. The boom 34 has a proximal end part and a distal end part opposite to the proximal end part, and the proximal end part is connected to the turning frame 22 so as to allow the boom 34 to be rotationally moved around a horizontal axis, that is, to be raised and lowered. The arm 36 has a proximal end part and a distal end part opposite to the proximal end part, and the proximal end part is connected to the distal end part of the boom 34 movably rotationally about a horizontal axis. The bucket 38 is a tip attachment forming the tip part of the work attachment, connected to the distal end part of the arm 36 movably rotationally about a horizontal axis to be thereby capable of performing an excavation motion (scoop motion) and an opening motion (earth removal motion) opposite to the excavation motion. The tip attachment is not limited to the bucket 38 but allowed to be also, for example, a crusher for crushing a work object or a lifting magnet for attracting the work object by magnetic force.

The drive device 40 actuates a plurality of movable parts of the work machine 2 to make the plurality of movable parts perform motions for work. The drive device 40 according to the embodiment is configured to hydraulically move the plurality of movable parts, including respective hydraulic actuators corresponding to the plurality of movable parts and a non-illustrated hydraulic circuit.

The plurality of hydraulic actuators include a non-illustrated traveling motor, a turning motor 42, and a plurality of extendable hydraulic cylinders, namely, a boom cylinder 44, an arm cylinder 46 and a bucket cylinder 48. Each of the traveling motor and the turning motor 42 is a hydraulic motor, the traveling motor disposed to bring the lower traveling body 10 into a traveling motion, the turning motor 42 connected to the upper turning body 20 so as to turn the upper turning body 20 with respect to the lower traveling body 10. The boom cylinder 44 is disposed so as to cause the boom 34 to be raised and lowered with respect to the upper turning body 20 by the expansion and contraction of the boom cylinder 44. The arm cylinder 46 is disposed so as to cause the arm 36 to be rotationally moved with respect to the boom 34 by the expansion and contraction of the arm cylinder 46. The bucket cylinder 48 is disposed so as to cause the bucket 38 to be rotationally moved with respect to the arm 36 by the expansion and contraction of the bucket cylinder 48. In the case where the tip attachment includes a movable part, for example, in the case where the tip attachment is a crusher that performs a pinching motion, the plurality of hydraulic actuators may further include one to actuate the movable part of the tip 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, which is a non-illustrated power source installed on the work machine 2, to thereby suck and discharge hydraulic fluid in the tank. The plurality of control valves are provided for the plurality of hydraulic actuators, respectively, and make respective opening and closing motions to change the flow direction and flow rate of the hydraulic fluid that is supplied from the hydraulic pump to each of the hydraulic actuators. The plurality of solenoid valves are provided for the plurality of control valves, respectively, specifically, provided so as to cause the plurality of control valves to perform respective opening and closing motions corresponding to respective electric signals input to the solenoid valves. By the respective inputs of the electric signals to the solenoid valves, thus, the driving of the plurality of movable parts by the plurality of hydraulic actuators is enabled to be controlled, that is, the motion of the work machine 2 is enabled to be controlled.

The engine (power source) is started by the turning-on of the key switch 58 shown in FIG. 2. The key switch 58 is turned on by an ON operation, in which an operator inserts the engine key into the key cylinder and rotates the engine key, to thereby output a start command signal. The start command signal is input to a non-illustrated engine ECU attached to the engine, and input to the control system 60.

The drive device 40 is not limited to one that actuates all of the movable parts hydraulically. For example, the drive device 40 may include a plurality of electric actuators and an electric circuit that controls the plurality of electric actuators, in place of a part or all of the plurality of hydraulic actuators and the hydraulic circuit.

The work machine 2 has a plurality of work modes. Specifically, the work machine 2 has a normal mode and has a crane mode corresponding to the suspension work mode. In the normal mode, the work machine 2 performs a motion for performing original work with use of the bucket 38, which is a tip attachment, specifically, normal work including excavation work, earth removal work, leveling work and the like. In the crane mode, the work machine 2 performs a motion for performing suspension work by use of the work device 30. Specifically, the work device 30 includes a movable part (the distal end of the arm 36 in the example shown in FIG. 1) that can be moved by the drive device 40 and allows a suspension tool (suspension hook) 52 to be detachably attached to the movable part, and the suspension work by use of the work device 30 can be performed with a suspended load 56 suspended from the suspension tool 52, for example, through a wire rope 54 shown in FIG. 5.

The operation device 50 includes a plurality of operation members corresponding to the plurality of movable parts, respectively, allowing respective work operations to be applied to the operation members by an operator. Each of the operation members is, for example, an operation lever or an operation pedal. In the present embodiment, the respective work operations to be applied to the work members include a turning operation for turning the upper turning body 20, a boom operation for raising and lowering the boom 34, an arm operation for rotationally moving the arm 36, and a bucket operation for rotationally moving the bucket 38. In the case where the drive device 40 includes an attachment for moving the movable part of the tip attachment, the work operation may include a tip attachment operation for moving the movable part.

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

It is not limited where the operation device 50 is disposed. The operation device 50 may be disposed either in the cab 24 capably of being operated by an operator sitting on the operation seat or outside the work machine 2, for example, in a remote operation room.

The control system 60 includes a function of performing a motion restriction control for the work machine 2, including a plurality of elements for providing the function as shown in FIG. 2, namely, a suspension tool attachment detector 62, a suspension load detector 63, an object detector 64, a motion restriction control switch 66, a lock operation detector 67, a notification device 68 and a controller 70.

The suspension tool attachment detector 62 detects whether or not the suspension tool 52 is attached to the work device 30. The suspension tool attachment detector 62 may be either a contact type sensor that is switched from off to on when coming into contact with the suspension tool 52 or a non-contact type sensor (e.g., an optical sensor or an ultrasonic sensor) that detects the presence of the suspension tool 52 at a predetermined attachment position without contact with the suspension tool 52.

The suspension tool attachment detector 62 forms a mode detector that detects the current work mode of the work machine 2. Specifically, the mode detector detects the work mode that is currently adopted out of 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 suspension load detector 63 is composed of a load sensor, which detects a suspension load that is a load acting on the suspension tool 52 when the suspension tool 52 is attached to the tip of the work device 30. The suspension load detected by the suspension load detector 63, when being 0 or a very small value that is very close to 0, allows it to be judged that the suspension work has not been actually executed yet by the work device 30. The suspension load detector 63, thus, can serve as a suspension work detector for detecting whether or not the suspension work is executed by the work device 30. The suspension work detector may be, alternatively, either a switch configured to be turned on when a fixed or more suspension load acts on the suspension tool 52 or one configured to image-recognize the presence or absence of the suspended load 56.

The object detector 64 detects a monitoring object around 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 detector that acquires two-dimensional information (e.g., a position and a shape in an image) of an imaging object; a camera that generates two-dimensional information (monocular camera); a detector that acquires a distance image; a detector that generates three-dimensional information (e.g., a three-dimensional coordinate or a three-dimensional shape) of an imaging object based on a distance image; a detector that generates three-dimensional information by use of a razer light, for example, a LIDAR (Light Detection and Ranging) or a TOF (Time Of Flight) sensor; a device that detects three-dimensional information by use of a radio wave (for example, a millimeter wave radar); and a stereo camera.

The object detector 64 is preferably disposed at a position from which the rear of an operator can be monitored, for example, the rear end of the upper turning body 20. The object detector 64 may be disposed in at least one of the left and right sides of the upper turning body 20 in addition to or in place of the rear end. The object detector 64, alternatively, may be disposed so as to monitor a situation of the work machine 2 and the periphery thereof at a position away from the work machine 2 at a site where work is performed by the work machine 2.

The motion restriction control switch 66 is configured to allow a stop operation and a stop release operation to be applied to the motion restriction control switch 66 by an operator. The stop operation is an operation for stopping the controller 70 from executing the motion restriction control, that is, an operation for commanding the controller 70 to stop the motion restriction control, and the motion restriction control is a control for restricting the motion of the work machine 2, as specifically described below, based on the detection of the monitoring object by the object detector 64. The stop release operation is an operation for releasing the stop of the motion restriction control, that is, an operation for making the controller 70 resume the motion restriction control.

Similarly to the operation device 50, it is not limited where the motion restriction control switch 66 is to be disposed. The motion restriction control switch 66 may be either disposed at a position allowing the stop operation and the stop release operation to be applied by an operator sitting on the operation seat or provided in the remote operation room together with the operation device 50. The motion restriction control switch 66, alternatively, may be attached to any of the plurality of operation members included in the operation device 50.

The motion restriction control switch 66 only has to allow the stop operation and the stop release operation to be applied to the motion restriction control switch 66 by an operator, having a non-limited configuration. The motion restriction control switch 66 may be either a switch to which a physical operation is applied by an operator, such as a push type switch, a lever type switch, and a slide type switch, or a display including a display screen capable of displaying a touch panel to be operated by an operator. The display screen may be a screen of a mobile carried by an operator.

The lock operation detector 67 detects a lock operation that is applied to the work machine 2 by an operator, the lock operation being an operation for invalidating the work operation applied to the operation device 50 for making the work machine 2 perform motions. The work machine 2 further includes 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 detecting the lock operation. The operation lock device makes an operation lock action for invalidating the work operation when the lock operation detection signal is input.

The lock operation detector 67 may be either an operation switch that allows an operation (lock operation) to be directly applied to the lock operation detector 67 by an operator similarly to the operation device 50 or a lock operation detection switch that is turned between on and off in conjunction with the movement of a separated lock operation member to which a lock operation is to be applied, for example, a lock lever to be operated so as to open and close the entrance. The lock lever is switched between an opening position for opening the entrance to allow an operator to get on and off therethrough and a closing position for blocking the entrance to prevent an operator from getting on and off therethrough; the lock operation detection switch is brought into an ON state of outputting a lock command, when the lock lever is at the open position.

In the case where the drive device 40 includes a hydraulic circuit and the operation device 50 includes the plurality of remote control valves corresponding to the plurality of movable parts, respectively, it is preferable that the operation lock device includes a lock valve disposed in a pilot pressure supply path between the plurality of remote control valves and a pilot hydraulic source. The lock valve can collectively invalidate respective work operations to be applied to the plurality of remote control valves, specifically, can disable each of the remote control valves from outputting the pilot pressure corresponding to the work operation, with a simple configuration just for cutting off the pilot pressure supply path. In this case, the operation lock device may be configured to either allow the lock valve to be closed in direct linkage with the lock operation or allow the controller 70 or a lock control device different from the controller 70 to input a command signal to the lock valve to close the lock valve upon the input of the lock operation detection signal from the lock operation detector 67. In summary, the controller 70 may form a part of the operation lock device.

The notification device 68 performs the notification designated by the controller 70 to the operator. Similar to the operation device 50 and the motion restriction control switch 66, the place is not limited where the notification device 68 is to be disposed. The place only has to allow the notification device 68 notify an operator therefrom; the notification device 68 may be either at a position close to the operation seat or provided in the remote control chamber together with the operation device 50 and the motion restriction control switch 66. Alternatively, the notification device 68 may be equipped in a mobile carried by an operator.

The notification executed by the notification device 68 may be recognized by an operator either visually or auditorily. Specifically, the notification device 68 may be either a display that displays the content of the notification on a screen or a speaker that outputs the content of the notification as a voice. The display may display a touch panel including the motion restriction control switch 66 on the screen. In summary, the motion restriction control switch 66 and the notification device 68 may be configured as a single display.

In the present embodiment, the controller 70 is a processor that performs the control of the motion of the work machine 2 and the control of the notification by the notification device 68 based on the information input from the operation device 50, the suspension tool attachment detector 62, the suspension load detector 63, the object detector 64, the motion restriction control switch 66 and the key switch 58, preferably including a computer with a storage unit and an arithmetic unit. Similarly to the operation device 50, the controller 70 may be either installed on the work machine 2 or disposed outside the work machine 2. The controller 70, for example, may be included in a cloud server.

As main functions for executing the control, the controller 70 includes a mode judgment part 72, a drive control part 74 and a notification control part 76, which are shown in FIG. 2, the functions provided by the arithmetic unit executing the program stored in the storage unit. The program includes a control program for performing the motion restriction control.

The mode judgment part 72 judges the current work mode of the work machine 2 based on the presence or absence of the detection signal input from the suspension tool attachment detector 62, that is, the presence or absence of the attachment of the suspension tool 52 to the tip of the work device 30. Specifically, the mode judgment part 72 judges the work mode to be the crane mode when the attachment of the suspension tool 52 is detected, and judges the work mode to be a mode other than the crane mode, namely, the normal mode in the present embodiment, when no attachment of the suspension tool 52 is detected.

The suspension tool attachment detector 62, thus, serves as a mode detector that acquires information for determining the current work mode. The mode detector, alternatively, may be a mode selection switch. The mode selection switch receives an operation by an operator for selecting the work mode, and inputs a signal for specifying the selected work mode to the controller 70. The mode selection switch can input information for directly specifying the work mode to the controller 70.

The drive control part 74 controls the drive of the work machine 2 by the drive device 40, thereby performing the following control on the motion of the work machine 2.

A. Basic Control

Based on an operation signal (electric signal) input from the operation device 50, the drive control part 74 according to the present embodiment controls the drive by the drive control part 74 so as to make the plurality of movable parts perform motions corresponding to the operation signal, that is, motions corresponding to the work operation. Specifically, the drive control part 74 generates a command signal corresponding to the work operation, and inputs the command signal to the solenoid valve corresponding to the work operation among the plurality of solenoid valves included in the drive device 40 to thereby activate the hydraulic actuator corresponding to the work operation.

The drive control part 74 may change the control content according to the work mode. For example, when the crane mode is detected, the drive control part 74 may execute control to reduce the speed of the drive of the work device 30 or the speed of the turning drive of the upper turning body 20 by the drive device 40 as compared with the normal mode in order to reduce the swing of the suspended load 56.

The case where the operation device 50 includes the plurality of remote control valves, from which respective operation signals (pilot pressures) are directly input to the plurality of control valves, requires no execution of the basic control by the drive control part 74.

B. Motion Restriction Control

The drive control part 74 executes the motion restriction control until the application of the stop operation to the motion restriction control switch 66. As described above, the motion restriction control is a control for restricting the motion of the work machine based on the detection of the monitoring object by the object detector 64. Specifically, when the object detector 64 detects a monitoring object (person or obstacle) entering a monitoring area set around the work machine 2, the drive control part 74 performs control for decelerating the motion of the movable part so as to prevent the monitoring object and the movable part of the work machine 2 from coming into contact with or coming close to each other. The deceleration includes quick stop of the movable part.

In the present embodiment, the deceleration is performed by changing the command signal to be input to the solenoid valve corresponding to the movable part to be decelerated among the plurality of solenoid valves (i.e., by reducing the pilot pressure). Also in an aspect where the operation device 50 includes the plurality of remote control valves and the drive control part 74 executes no basic control, the target movable part is enabled to be decelerated by input of a pressure-reducing command signal to solenoid valves interposed between the plurality of remote control valves and the plurality of control valves, similarly to the above.

The restriction of the motion of the work machine 2 is not limited to a direct restriction but allowed to be also an indirect restriction. For example, the “motion restriction control” according to the present invention encompasses giving an operator a warning for prompting the operator to perform such an operation as to reduce the motion of the work machine 2 to thereby restrict the motion of the work machine as a result. The warning may be performed by use of either the notification device 68 or an alarm other than the notification device 68.

The drive control part 74 is configured to automatically start the execution of the motion restriction control based on the detection of the monitoring object by the object detector 64 when the key switch 58 is turned on to start the engine as a power source from the stopping state of the engine. The automatic start of the motion restriction control reliably prevents the motion restriction control from failing to be performed even after the start of the engine without the operator's recognition.

The notification control part 76 executes a notification control. The notification control is a control of generating an appropriate notification command signal and inputting the notification command signal to the notification device 68 to thereby make the notification device 68 perform the notification corresponding to the notification command signal. Specifically, as follows.

C. Stop Instruction Notification Control

The notification control part 76 makes the notification device 68 notify a stop instruction when the mode judgment part 72 judges the current work mode to be the crane mode during the execution of the motion restriction control. The stop instruction is an instruction for prompting an operator to apply the stop operation for stopping the motion restriction control to the motion restriction control switch 66, for example, the display of the message “STOP MOTION RESTRICTION CONTROL DURING WORK IN CRANE MODE”.

The stop instruction, which prompts an operator to perform the stop operation for stopping the motion restriction control, effectively restrains the suspended load from being swung largely by the execution of the motion restriction control to restrict the motion of the work machine during the suspension work. The stop instruction is also effective in a case where the restriction of the motion of the work machine is indirect, that is, a warning to an operator as described above. It is effectively inhibited that an operator given the warning manually performs rapid deceleration of the motion of the work machine 2 during the suspension work by which the suspended load 56 is swung.

The stop of the motion restriction control is, thus, not automatically performed by the controller 70 regardless of the intention of an operator but performed after the actual application of the stop operation to the motion restriction control switch 66 by an operator given the notification of the stop instruction by the notification device 68, which enables the stop of the motion restriction control to be reliably recognized by the operator.

D. Additional Notification Control

After the notification of the stop instruction, the notification control part 76 makes the notification device 68 perform an additional notification of the stop instruction when the execution of the suspension work is further detected, that is, when the suspension load detected by the suspension load detector 63 becomes equal to or greater than a fixed value in the present embodiment. This inhibits the suspension work from being continued without the stop of the motion restriction control. The additional notification may be either a notification to be re-performed after the stop of the first notification of the stop instruction or a notification to be performed so as to reinforce the stop instruction during the continuation of the stop instruction. The former additional notification, namely, a re-notification, may have either a content equivalent to the content of the first notification of the stop instruction or a content different therefrom. The latter notification, namely, a reinforcing notification, may be either a notification to be performed so as to overlap the first notification or a notification to emphasize the first notification, for example, an increase in the amount of light, a blink, a color change in the character that indicates the stop instruction or a part in the periphery thereof, or an increase in sound volume of the voice corresponding to the stop instruction.

The notification control part 76 is configured to stop the notification of the stop instruction by the notification device 68 regardless of whether the work mode is the crane mode (suspension work mode) or the normal mode (mode other than the suspension work mode) when the lock operation is detected by the lock operation detector 67, while configured to make the notification device 68 notify the stop instruction when the detection of the lock operation becomes absent when the crane mode is detected and the motion restriction control is continued. The stop of the notification of the stop instruction when the lock operation is detected prevents the stop instruction from being wastefully notified despite the state in which the work operation is invalidated by the lock operation, that is, the state in which the motion of the work machine 2 including the motion for the suspension work is forcibly stopped. Besides, the notification of the stop instruction upon the release of the lock operation effectively inhibits the motion restriction control from being executed in the crane mode when the work operation becomes validated by the release.

Although the drive control part 74 is configured, as described above, to automatically start the motion restriction control when the key switch 58 is turned on to cause the engine to be started after the stop of the engine, the notification control part 76 is configured to make the notification device 68 notify the stop instruction when the work mode detected at the start of the engine is the crane mode. This effectively inhibits the motion restriction control, which is automatically started at the start of the engine, from being continued also in the crane mode.

E. Stop State Notification Control

The notification control part 76 is configured to make the notification device 68 perform a notification for informing an operator that the motion restriction control is being stopped, namely, a stop state notification, when the motion restriction control is stopped in spite that the work mode is a work mode other than the crane mode, that is, the normal mode. The stop state notification is, for example, the display of the message “MOTION RESTRICTION CONTROL BEING STOPPED, PAY ATTENTION TO SURROUNDINGS DURING OPERATION”. In addition to such a notification about the stop state, more notification may be performed for prompting an operator to apply a stop release operation to the motion restriction control switch 66.

The notification of the stop state allows an operator to reliably recognize that the motion restriction control is in the stop state in the normal mode, which is a work mode other than the crane mode, to call attention to the operator, thereby enabling high safety to be secured also in the normal mode.

FIG. 3 shows a suitable specific example of the notification provided by the notification control part 76 described above. In the present example, the notification device 68 includes a display and a speaker, wherein the message is continuously blinked and further alarm sounds are intermittently emitted from the speaker by a predetermined number of times (e.g., five times). For example, upon the change of the work mode from the normal mode to the crane mode during the execution of the motion restriction control (the first row in the figure), the message “STOP MOTION RESTRICTION CONTROL DURING WORK IN CRANE MODE” is continuously blinked on the display and further the alarm sounds are intermittently emitted by the predetermined number of times. Thereafter, upon the detection of the execution of the actual suspension work, that is, at the point in time when the suspension load detected by the suspension load detector 63 becomes equal to or more than a fixed value (the second row in the figure) in the present embodiment, the alarm sounds are intermittently re-emitted by the predetermined number of times (for example, five times), as the additional notification, during the continuation of the message. The intermittent alarm sounds may be replaced, for example, with a continuous sound to be continued for a certain period of time.

Next will be described the flow of the motion restriction control performed by the controller 70 with reference to the flowchart of FIG. 4.

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

The controller 70 judges whether or not a lock operation is applied to the operation lock device (step S14). If the lock operation is applied (YES in step S14), that is, if the operation lock device is activated to invalidate the work operation by the operator, the notification control part 76 of the controller 70 stops all of the notifications from being performed by the notification device 68 (step S16), for the motions of the work machine 2 including the motion for the suspension work is impossible, hindering the continuation of the motion restriction control from having any influence to the safety.

If the lock operation is absent or released (NO in step S14), the controller 70 executes the stop of the motion restriction control and the release of the stop in accordance with the operation applied to the motion restriction control switch 66, and the notification control in accordance with the execution/stop of the motion restriction control and the detected work mode (step S20 to step S40). These controls are continued, as described above, until the key switch 58 is switched off (NO in step S42).

Specifically, until the application of the stop operation to the motion restriction control switch 66 (NO in step S20), the drive control part 74 of the controller 70 continues the motion restriction control (step S22). Meanwhile, the mode judgment part 72 of the controller 70 judges whether the current work mode is the crane mode (suspension work mode) or the normal mode (work mode other than the suspension work mode) based on the presence or absence of detection of the attachment of the suspension tool 52 by the suspension tool attachment detector 62 (step S24); when the current work mode is the crane mode (YES in step S24), the notification control part 76 makes the notification device 68 notify the stop instruction that prompts an operator to perform the stop operation for stopping the motion restriction control (step S26). Thereafter, if the execution of the actual suspension operation is further detected (YES in step S28), the notification control part 76 makes the notification device 68 perform an additional notification (step S30).

When the work mode is not the crane mode (in the present embodiment, in the normal mode; NO in step S24), neither of the stop instruction notification and the additional notification is performed even during the execution of the motion restriction control.

Thereafter, at the point in time when an operator given the stop instruction notification actually applies the stop operation to the motion restriction control switch 66 (YES in step S20), the drive control part 74 stops the motion restriction control (step S32). In other words, the drive control part 74 continues the motion restriction control until the application of the stop operation to the motion restriction control switch 66 (NO in step S20 and step S22) regardless of the work mode. This reliably prevents the motion restriction control from being stopped without sufficient recognition by an operator.

During the stop of the motion restriction control, if the work mode is not the crane mode (in the present embodiment, if the operation mode is the normal mode; NO in step S34), the notification control part 76 makes the notification device 68 perform the stop state notification for notifying an operator that the motion restriction control is being stopped (step S36). The stop of the motion restriction control (step S32) and the stop state notification (step S36) are continued until the stop release operation is applied to the motion restriction control switch 66 (NO in step S38); when the stop release operation is applied to the motion restriction control switch 66 (YES in step S38), the drive control part 74 resumes the motion restriction control (step S40).

All of the above-described controls are ended when the key switch 58 is switched off (YES in step S42).

The present invention is not limited to the embodiments and modifications described above, including, for example, the following aspects.

The motion restriction control switch 66 may allow only the stop operation out of the stop operation and the stop release operation to be applied thereto. The drive control part 74 may be configured to automatically resume the motion restriction control at the time when the work mode is switched from the crane mode (suspension work mode) to the normal mode (mode other than the suspension work mode), for example, after the motion restriction control is stopped by the stop operation. On the other hand, if not only the stop operation but also the stop release operation can be applied to the motion restriction control switch 66 as in the above-described embodiment and the drive control part 74 is configured to resume the motion restriction control under the condition of the stop release operation, not only the stop of the motion restriction control but also the resumption of the motion restriction control after the stop can be reliably recognized by an operator.

The plurality of work modes only has to include a suspension work mode (the crane mode in the embodiment), while the work mode other than the suspension work mode is not limited. The work mode other than the suspension operation mode may include a mode corresponding to work other than work by use of the bucket 38, for example, work by another tip attachment with which the bucket 38 is exchanged (such as a crusher).

Besides, the control system can be widely applied to also a work machine that is other than a hydraulic excavator and capable of performing at least a suspension work.

As has been described, provided is a control system that enables appropriate motion restriction control to be executed according to a work mode while sufficiently recognized by an operator.

Provided is a control system for a work machine, which has a plurality of work modes including a suspension work mode. The control system includes a mode detector, an object detector, a motion restriction control switch, a notification device, and a controller. The mode detector detects a current work mode among the plurality of work modes. The object detector detects a monitoring object around the work machine. The notification device is capable of notifying an operator. The controller is capable of performing a motion restriction control for restricting a motion of the work machine based on the detection of the monitoring object. The motion restriction control switch allows a stop operation to be applied to the motion restriction control switch by an operator. The controller is configured to perform making the notification device notify a stop instruction for prompting the stop operation when the suspension work mode is detected during execution of the motion restriction control, continuing the motion restriction control until application of the stop operation to the motion restriction control switch and stopping the motion restriction control upon the application of the stop operation.

The controller in the control system, making the notification device notify the stop instruction to prompt an operator to stop the motion restriction control when the suspension work mode is detected during the execution of the motion restriction control, can effectively restrain the suspended load from being largely swung by the execution of the motion restriction control, i.e., the restriction of the motion of the work machine, during the suspension work in the suspension work mode. Moreover, continuing the motion restriction control until the application of the stop operation to the motion restriction control switch and stopping the motion restriction control after the actual application of the stop operation to the motion restriction control switch by an operator, the controller allows the stop of the motion restriction control to be reliably recognized by an operator.

The controller is preferably configured to stop the motion restriction control only when the stop operation is applied to the motion restriction control switch. This allows the stop of the motion restriction control to be more reliably recognized by an operator.

The motion restriction control preferably includes a control for decelerating the motion of the work machine (including rapidly stopping). The control allows the work machine to be more reliably inhibited from coming into contact with or close to the monitoring object detected by the object detector, while the notification of the stop instruction effectively restrains a suspended load from being largely swung by the deceleration of the motion of the work machine. The motion restriction control, alternatively, may be a control to indirectly restrict the motion of the work machine, for example, a control to give an operator a warning to restrict the motion of the work machine.

Preferably, the control system further includes a suspension work detector that detects execution of suspension work by the work machine, wherein the controller is configured to make the notification device perform an additional notification of the stop instruction when the suspension work detector detects the execution of the suspension work after the notification of the stop instruction. This inhibits the suspension work more reliably from being continued without the stop of the motion restriction control. The additional notification may be either a notification to be re-performed after the stop of the notification of the stop instruction or a notification to be performed to reinforce the stop instruction during the continuation of the stop instruction. The content of the additional notification may be either equivalent to the content at the time of notification of the stop instruction or different therefrom.

The control system may further include a lock operation detector that detects a lock operation. The lock operation is an operation for invalidating a work operation performed by an operator for moving the work machine. In this case, preferably, the controller is configured to stop the notification of the stop instruction from being performed by the notification device, regardless of the work mode, when the lock operation is detected, and configured to make the notification device notify the stop instruction when the suspension work mode is detected during execution of the motion restriction control with no detection of the lock operation. The stop of the notification of the stop instruction prevents the stop instruction for stopping the motion restriction control from being wastefully notified in spite of the invalidation of the work operation to prevent the work machine from performing any motion. Meanwhile, the notification of the stop instruction when the detection of the lock operation becomes absent effectively inhabits the motion restriction control from being continued in the suspension work mode after the release of the lock operation.

In the case of the work machine including a power source, the controller may be configured to automatically execute the motion restriction control when the power source is started. This enables the motion restriction control to be reliably performed after the start of the power source. Furthermore, in this case, making the notification device notify the stop instruction when the work mode is the suspension work mode at the start point of the power source, the controller can effectively inhibit the suspension work from being performed after the automatic start of the motion restriction control.

In this aspect, in the case of the control system further including the lock operation detector, it is preferable that the controller is configured to make the notification device notify the stop instruction only when the work mode is the suspension work mode at the start of the power source and the lock operation is not detected.

It is preferable that the motion restriction control switch allows a stop release operation in addition to the stop operation to be applied to the motion restriction control switch and the controller is configured to resume the motion restriction control only when the stop release operation is applied during the stop of the motion restriction control. This allows not only the stop of the motion restriction control but also the resumption of the motion restriction control after the stop to be reliably recognized by an operator.

The controller is preferably configured to make the notification device perform a notification that the motion restriction control is being stopped when the operation mode is a work mode other than the suspension work mode and the motion restriction control is stopped. This allows it to be reliably recognized by an operator that the motion restriction control is being stopped in spite that the work mode is a work mode other than the suspension work mode, thereby allowing high safety to be secured even in a work mode other than the suspension work mode.

Also provided is a control method for a work machine having a plurality of work modes including a suspension work mode. The method includes: performing a motion restriction control for restricting motion of the work machine based on detection of a monitoring object until application of a stop operation to the motion restriction control switch by an operator; stopping the motion restriction control upon the application of the stop operation to the motion restriction control switch; and making the notification device notify a stop instruction for prompting the stop operation when the suspension work mode is detected during execution of the motion restriction control.

Also provided is a control program for making a motion restriction control performed for restricting a motion of a work machine having a plurality of work modes including a suspension work mode. The control program is read by a computer to thereby make the computer execute: performing a motion restriction control for restricting motion of the work machine based on detection of a monitoring object until application of a stop operation to the motion restriction control switch by an operator; stopping the motion restriction control upon the application of the stop operation to the motion restriction control switch; and making the notification device notify a stop instruction for prompting the stop operation when the suspension work mode is detected during execution of the motion restriction control.

Also provided is a recording medium in which the control program is recorded, 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 suspension work mode, comprising:

a mode detector that detects a current work mode among the plurality of work modes;

an object detector that detects a monitoring object around the work machine;

a notification device capable of performing a notification to an operator;

a controller capable of performing a motion restriction control for restricting a motion of the work machine based on detection of the monitoring object; and

a motion restriction control switch allowing a stop operation to be applied to the motion restriction control switch by an operator, wherein

the controller is configured to perform making the notification device notify a stop instruction for prompting the stop operation when the suspension work mode is detected during execution of the motion restriction control, continuing the motion restriction control until application of the stop operation to the motion restriction control switch and stopping the motion restriction control upon the application of the stop operation.

2. The control system according to claim 1, wherein the controller is configured to stop the motion restriction control only when the stop operation is applied to the motion restriction control switch.

3. The control system according to claim 1, wherein the motion restriction control performed by the controller includes a control for decelerating the motion of the work machine.

4. The control system according to claim 1, further comprising a suspension work detector that detects execution of suspension work by the work machine, wherein the controller is configured to make the notification device perform an additional notification of the stop instruction when the suspension work detector detects the execution of the suspension work after a notification of the stop instruction.

5. The control system according to claim 1, further comprising a lock operation detector that detects a lock operation, which is an operation for invalidating a work operation by an operator for operating the work machine, wherein the controller is configured to stop the notification device from notifying the stop instruction regardless of the work mode when the lock operation is detected, and configured to make the notification device notify the stop instruction when the suspension work mode is detected during execution of the motion restriction control.

6. The control system according to claim 1, wherein the work machine includes a power source, and the controller is configured to automatically execute the motion restriction control when the power source is started, and configured to make the notification device notify the stop instruction when the work mode is the suspension work mode at start of the power source.

7. The control system according to claim 5, wherein the work machine includes a power source, and the controller is configured to automatically execute the motion restriction control when the power source is started, and configured to make the notification device perform a notification of the stop instruction only when the work mode is the suspension work mode at start of the power source and the lock operation is not detected.

8. The control system according to claim 1, wherein the motion restriction control switch allows a stop release operation, in addition to the stop operation, to be applied to the motion restriction control switch, and the controller is configured to resume the motion restriction control only when the stop release operation is applied during the stop of the motion restriction control.

9. The control system according to claim 1, wherein the controller is configured to make the notification device perform a notification that the motion restriction control is being stopped when the operation mode is a work mode other than the suspension work mode and the motion restriction control is stopped.

10. A control method for a work machine having a plurality of work modes including a suspension work mode, comprising:

performing a motion restriction control for restricting a motion of the work machine based on detection of a monitoring object until application of a stop operation to a motion restriction control switch by an operator;

stopping the motion restriction control upon the application of the stop operation to the motion restriction control switch; and

making a notification device notify a stop instruction that prompts the stop operation when the suspension work mode is detected during execution of the motion restriction control.

11. A control program for making a motion restriction control for restricting a motion of a work machine having a plurality of work modes including a suspension work mode executed, the program being read by a computer to thereby make the computer execute:

performing the motion restriction control based on detection of a monitoring object until application of a stop operation to a motion restriction control switch by an operator;

stopping the motion restriction control upon the application of the stop operation to the motion restriction control switch; and

making a notification device notify a stop instruction that prompts the stop operation when the suspension work mode is detected during execution of the motion restriction control.

12. A recording medium in which the control program according to claim 11 is recorded, allowing the control program to be read by the computer.