Patent Publication Number: US-2023151588-A1

Title: Work Machine Control Method, Work Machine Control Program, Work Machine Control System, And Work Machine

Description:
TECHNICAL FIELD 
     The present invention relates to a work machine control method, a work machine control program, a work machine control system, and a work machine, which are used for a work machine controlled in response to an operation for an operation unit. 
     BACKGROUND ART 
     As a related technology, a work machine equipped with a machine body, a work instrument installed on the machine body, and a hydraulic breaker attached to a tip portion of the work instrument is known (see, for example, Patent Document 1). The work machine according to the related technology is further equipped with a switch that can switch between an auto-hammer prohibited state that disables the hydraulic breaker and an auto-hammer permitted state that enables the hydraulic breaker to operate. So as to prevent unintentional hitting, this work machine is normally set in the auto-hammer prohibited state, and is switched to the auto-hammer permitted state by operating the switch. Specifically, the work machine shifts to an auto-hammer standby state when the switch is operated in the auto-hammer prohibited state, and shifts to the auto-hammer permitted state when the switch is operated again within a certain period in the auto-hammer standby state. 
     PRIOR ART DOCUMENT 
     Patent Document 
     
         
         Patent Document 1: Japanese Unexamined Patent Application Publication No. 2010-209641 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     In the above related technology, operating the switch switches the hydraulic breaker from the auto-hammer prohibited state to the auto-hammer permitted state; therefore, an operator needs to carefully operate the hydraulic breaker so as to prevent, for example, the hydraulic breaker from suddenly becoming operable and starting to hit. 
     An object of the present invention is to provide a work machine control method, a work machine control program, a work machine control system, and a work machine that easily reduce a burden on an operator for an operation. 
     Solution to Problem 
     A work machine control method according to one aspect of the present invention, includes: accepting an operation for an operation unit for controlling a work machine; monitoring a specific event to be monitored; and determining, with the specific event occurring, whether or not a determination condition for the operation for the operation unit is met. 
     A work machine control program according to one aspect of the present invention is a program that causes one or more processors to execute the work machine control method. 
     A work machine control system according to one aspect of the present invention, includes: an acquisition processing unit; a monitor processing unit; and a determination processing unit. The acquisition processing unit accepts an operation for an operation unit for controlling a work machine. The monitor processing unit monitors a specific event to be monitored. The determination processing unit determines, with the specific event occurring, whether or not a determination condition for the operation for the operation unit is met. 
     A work machine according to one aspect of the present invention, includes: a work machine control system; and a machine body controlled in response to the operation for the operation unit. 
     Advantageous Effects of Invention 
     According to the present invention, a work machine control method, a work machine control program, a work machine control system, and work machine that easily reduce a burden on an operator for an operation can be provided. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic perspective view showing an overall configuration of a work machine according to a first embodiment. 
         FIG.  2    is a schematic block diagram of the work machine according to the first embodiment. 
         FIG.  3    is a schematic external view of an operation unit of the work machine according to the first embodiment. 
         FIG.  4    is a schematic external view of a display unit of the work machine according to the first embodiment. 
         FIG.  5    is a flowchart showing an operation example of a work machine control system according to the first embodiment. 
         FIG.  6    is a timing chart showing an operation example of a work machine control system according to the first embodiment. 
         FIG.  7    shows an example of a display screen displayed on the display unit of the work machine according to the first embodiment. 
         FIG.  8    is a flowchart showing an operation example of a work machine control system according to a second embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of the present invention will be described below with reference to the accompanying drawings. The following embodiments are each an embodied example of the present invention and are not intended to limit the technical scope of the present invention. 
     First Embodiment 
     [1] Overall Configuration 
     As shown in  FIG.  1   , a work machine  3  according to the present embodiment has a machine body  30  provided with a travel unit  31 , a swivel unit  32 , and a work unit  33 . The work machine  3  further has a work machine control system  1  (hereinafter, simply referred to as a “control system  1 ”), as shown in  FIG.  2   . Additionally, as shown in  FIGS.  1  and  2   , the machine body  30  further has a display unit  2 , a drive unit  34 , an operation unit  35 , a control valve  36 , a cutoff switch  371 , a cutoff lever  372 , and the like. 
     The “work machine” in the present disclosure refers to a machine for various types of work, examples thereof including work vehicles such as a backhoe (including a hydraulic excavator and a mini excavator), a wheel loader and a carrier. The work machine  3  is provided with the work unit  33  so configured as to be capable of executing one or more operations. The work machine  3  is not limited to the “vehicle”, but may be, for example, a work vessel, or a flying work body such as a drone or a multi-copter. Further, the work machine  3  is not limited to a construction machine (construction equipment), but may also be an agricultural machine (farm equipment) such as a rice transplanter, a tractor or a combine harvester. According to the present embodiment, unless particularly specified, a case in which the work machine  3  is a riding-type backhoe and can execute digging, land preparation, trenching, or loading operations as its work will be taken as an example. 
     Further, according to the present embodiment, for convenience of description, a vertical direction in a state where the work machine  3  is usable is defined as an upper/lower direction D 1 . Further, a front/rear direction D 2  and a right/left direction D 3  are each defined based on a direction viewed from a user (operator) riding on (a drive unit  321  of) the work machine  3  in a non-swivel state of the swivel unit  32 . In other words, each of the directions used in the present embodiment is a direction defined based on the machine body  30  of the work machine  3 , and a direction in which the machine body  30  moves at the time of the work machine  3  moving forward is referred to as “front”, and a direction in which the machine body  30  moves at the time of the work machine  3  moving rearward is referred to as “rear”. Similarly, a direction in which a front end portion of the machine body  30  moves at the time of the work machine  3  swiveling to the right is referred to as “right,” and a direction in which the front end portion of the machine body  30  moves at the time of the work machine  3  swiveling to the left is referred to as “left”. However, these directions are not intended to limit a use direction (a direction in use) of the work machine  3 . 
     The work machine  3  includes an engine serving as a power source. As one example in the present embodiment, the engine is a diesel engine. The engine is driven by fuel (in this case, light oil) supplied from a fuel tank. In the work machine  3 , a hydraulic pump is driven by the engine, for example, and hydraulic oil is supplied from the hydraulic pump to hydraulic actuators (including hydraulic motor  43 , hydraulic cylinder  44  and the like) of the various portions of the machine body  30 , thereby to drive the machine body  30 . The above work machine  3  can be controlled, for example, by a user (operator) boarding the drive unit  321  of the machine body  30  to operate the operation unit  35  such as operation levers  351 ,  352  (see  FIG.  3   ). 
     In the present embodiment, it is assumed that the work machine  3  is a passenger-use backhoe as described above; therefore, the work unit  33  is driven according to the operation by the user (operator) riding on the drive unit  321 , thereby to execute work such as excavation work. The drive unit  321 , on which the user rides, is provided on the swivel unit  32 . 
     Here, the display unit  2  and the operation unit  35  are installed on the drive unit  321  of the machine body  30 ; the user can operate the operation unit  35  while viewing the work machine  3 &#39;s various information displayed on the display unit  2 . As an example, a display screen of the display unit  2  displays information on an operation state of the work machine  3 , such as cooling water temperature and hydraulic oil temperature, so that the user can check, on the display unit  2 , the information that is necessary for operating the operation unit  35  and that is on the operation state of the work machine  3 . 
     The travel unit  31  has a traveling function, and is so configured as to be capable of traveling (including swiveling) on the ground. The travel unit  31  includes a pair of right and left crawlers  311  and a blade  312 , for example. The travel unit  31  further includes a travel-directed hydraulic motor  43  (hydraulic actuator) for driving the crawlers  311 . 
     The swivel unit  32  is provided above the travel unit  31  and is so configured as to swivel, relative to the travel unit  31 , about a rotation shaft along a vertical direction. The swivel unit  32  has a swivel-directed hydraulic motor (a hydraulic actuator), and the like. On the swivel unit  32 , other than the drive unit  321 , an engine, the hydraulic pump, and the like is installed. At the front end portion of the swivel unit  32 , there is provided a boom bracket  322  on which the work unit  33  is mounted. 
     The work unit  33  is so configured as to execute one or more operations. The work unit  33  is supported by the boom bracket  322  of the swivel unit  32 , and executes operations. The work unit  33  has an attachment  331 . The attachment  331  is an optional tool (work tool) selected from several types of tools according to the nature of the work. The attachment  331 , as an example, is detachably attached to the machine body  30 , and is replaced according to the nature of the work. The attachments  331  for work machine  3  include various tools such as breakers, augers, crushers, forks, buckets, fork claws, steel cutters, asphalt cutters, mowers, rippers, mulchers, tilt rotators, and tampers. 
     The work unit  33  further has a boom  332 , an arm  333 , and a hydraulic actuator (including hydraulic cylinder  44 , hydraulic motor, and the like), and the like. The attachment  331  is attached to the tip end of the arm  333 . Here, the work unit  33  moves under power from the engine as the power source. Specifically, the hydraulic pump is driven by the engine, and hydraulic oil is supplied from the hydraulic pump to the hydraulic actuator in the work unit  33  thereby to move the work unit  33 . 
     The boom  332  is rotatably supported at the boom bracket  322  of the swivel unit  32 . Specifically, the boom  332  is supported at the boom bracket  322  in a manner to rotate about a rotation axis along the horizontal direction. The boom  332  is so shaped as to extend upward from a base end portion supported at the boom bracket  322 . The arm  333  is coupled to a tip end of the boom  332 . The arm  333  is supported to the boom  332  in a manner to rotate about a rotation axis along the horizontal direction. 
     The work machine  3  is also equipped with the drive unit  34 , and the power from the drive unit  34  drives the attachment  331  of the work unit  33  thereby to execute various types of work. That is, in the work machine  3 , the attachment  331  such as a breaker or an auger, for example, is attached to the machine body  30  according to the nature of the work, and supplying the power from the drive unit  34  to the attachment  331  thereby to drive the attachment  331  performs the work. Therefore, at the time of performing the work with the work machine  3 , the user (operator) operating the operation unit  35 , for example, so as to cause the attachment  331  to make a desired movement controls the drive unit  34 &#39;s output (power), etc. supplied to the attachment  331 . 
     The drive unit  34  is used to supply power to the attachment  331 . As one example in the present embodiment, the drive unit  34  includes a unit (mechanism) such as a PTO (power take-off) to take out power from the engine as power for driving the attachment  331  including a hydraulic device. Specifically, to the attachment  331 , the drive unit  34  sends out the hydraulic oil from a hydraulic pump driven by the engine thereby to supply the hydraulic oil to the attachment  331 . The drive unit  34  adjusts the flowrate of hydraulic fluid supplied to the attachment  331 , thereby to adjust the magnitude of the power supplied to attachment  331 . 
     Here, the drive unit  34  has a plurality (four in the present embodiment as an example) of output ports  341  to  344  (see  FIG.  2   ). Each of the output ports  341  to  344  is so configured as to output power. Each of the output ports  341  to  344  can individually adjust the power, i.e., flowrate of the hydraulic oil, and the drive unit  34  outputs the power from each of the output ports  341  to  344 . In the present embodiment, each of the output ports  341  to  344  is a PTO port, so the output port  341  may be denoted as “PTO1”, the output port  342  as “PTO2”, the output port  343  as “PTO3”, and the output port  344  as “PTO4”. 
     Each of the travel unit  31  and the swivel unit  32 , in a manner similar to that of the work unit  33 , moves under power from the engine as the power source. That is, the hydraulic oil is supplied from the hydraulic pump to the hydraulic actuators (hydraulic motors) of the swivel unit  32  and travel unit  31 , thereby to move the swivel unit  32  and the travel unit  31 . 
     The operation unit  35  is placed at the drive unit  321  of the machine body  30 , and is a user interface for accepting the operation input by the user (operator). The operation unit  35  outputs an electric signal (operation signal) that accords to the operation by the user, for example, thereby to accept various operations by the user. As one example in the present embodiment, the operation unit  35  includes a pair of the operation levers  351 ,  352  (see  FIG.  3   ). The operation unit  35  is described in detail in the column “[2] Operation Unit”. 
     The control system  1  is mainly configured by a computer system having one or more processors such as a CPU (Central Processing Unit), and one or more memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory), executing various processes (information process). According to the present embodiment, the control system  1  is an integrated controller that controls the overall work machine  3 , and includes, for example, an electronic control unit (ECU). However, the control system  1  may be provided separate from the integrated controller, and may mainly include one processor or a plurality of processors. The control system  1  will be described in detail in the column “[3] Configuration of Control System”. 
     The display unit  2  is placed at the drive unit  321  of the machine body  30 , and is a user interface for accepting the operation input by the user (the operator) and outputting various types of information to the user. The display unit  2  outputs an electric signal that accords to the operation by the user, for example, thereby to accept various operations executed by the user. With this, the user (the operator) can view a display screen Dp 1  (refer to  FIG.  4   ) displayed on the display unit  2 , and can operate the display unit  2  as necessary. 
     As shown in  FIG.  2   , the display unit  2  includes a control unit  21 , an operation portion  22 , and a display portion  23 . The display unit  2  is so configured as to be communicable with the control system  1 , and can execute sending and receiving of data to and from the control system  1 . As one example in the present embodiment, the display unit  2  is a dedicated device used for the work machine  3 . 
     The control unit  21  controls the display unit  2  according to data from the control system  1 . Specifically, the control unit  21  outputs an electric signal that accords to the user&#39;s operation accepted by the operation portion  22 , and displays, in the display portion  23 , the display screen Dp 1  generated by the control system  1 . 
     The operation portion  22  is a user interface for accepting the user (operator)&#39;s operation input to the display screen Dp 1  displayed in the display portion  23 . The operation portion  22  outputs the electric signal that accords to a user U 1 &#39;s operation (refer to  FIG.  4   ), for example, thereby to accept various operations by the user U 1 . As one example in the present embodiment, the operation portion  22  includes a plurality (herein six) of mechanical push button switches  221  to  226 , as shown in  FIG.  4   . Along a periphery of a display area of the display portion  23 , the plurality of push button switches  221  to  226  is placed in the vicinity of the display area (a lower portion in the example in  FIG.  4   ). The push button switches  221  to  226  are associated with items (to be described below) displayed on the display screen Dp 1 ; operating any of the push button switches  221  to  226  operates (selects) any of the items on the display screen Dp 1 . 
     Further, the operation portion  22  may include a touch screen and an operation dial. Also in this case, operating for the operation portion  22  operates (selects) any of the items on the display screen Dp 1 . 
     The display portion  23  is a user interface for presenting information to the user U 1  (the operator), such as a liquid crystal display or organic EL display that displays various types of information. The display portion  23  presents various types of information to the user by means of display. As one example in the present embodiment, the display portion  23  is a full-color liquid crystal display with a backlight, and has a “horizontally-long” display area that is long in a horizontal direction as shown in  FIG.  4   . 
       FIG.  2    schematically shows a hydraulic circuit and electric circuit (electric connection) of the work machine  3  according to the present embodiment. In  FIG.  2   , the dotted line indicates a low-pressure (for pilot oil) oil path, and the single-dotted arrow indicates an electric signal path. 
     As shown in  FIG.  2   , the machine body  30  of the work machine  3  has the display unit  2 , the drive unit  34  and the operation unit  35 , as well as the control valve  36 , the cutoff switch  371 , the cutoff lever  372 , and the like. 
     Here, the drive unit  34  is equipped with a pilot-type direction-switch valve (control valve) that can switch the direction and flow of the hydraulic oil from the hydraulic pump. Supplying the pilot oil, which serves as an input command, from a pilot pump to the direction-switch valve drives the drive unit  34 . A solenoid type control valve  36  (electromagnetic valve) is inserted in a supply path of the pilot oil to the direction-switch valve. The control valve  36  moves in response to a control signal (current) from the control system  1 . The control valve  36  is here assumed to be a (solenoid type) proportional control valve, but can be, for example, an open/close valve that can switch between opening and cutting of the flow path. 
     The control valve  36  opens the flow path of the pilot oil in an energized state, i.e., in a state of a current as the control signal being supplied, and cuts off the flow path of the pilot oil in a de-energized state, i.e., in a state of the current as the control signal being cut off. Therefore, cutting of the supply current (control signal) to the control valve  36  makes the drive unit  34  inoperable, forcibly stopping the output of the drive unit  34  regardless of the operation unit  35 &#39;s operation. 
     The cutoff switch  371  is linked to the cutoff lever  372 . The cutoff lever  372  is placed in the drive unit  321  of the machine body  30 , and accepts an operation input by the user (operator). As one example in the present embodiment, the cutoff lever  372  can be operated along the upper/lower direction D 1 . When the cutoff lever  372  is in the “up position” which is the upper end position of a movable range, the cutoff switch  371  is “off”; when the cutoff lever  372  is in the “down position” which is the lower end position of the movable range, the cutoff switch  371  is “on”. Then, the cutoff switch  371  is connected to the control system  1 ; with the cutoff switch  371  in the off state, the control system  1  cuts off the current as the control signal, thereby forcibly cutting off the hydraulic circuit at the control valve  36 . When a cutoff valve is provided that is directly energized/de-energized by the on/off of the cutoff switch  371 , the hydraulic circuit may be cut off in conjunction with the cutoff switch  371  without the intervention of the control system  1 . That is, cutting off the hydraulic circuit by the cut-off valve when the cutoff switch  371  is off forcibly cuts off the hydraulic circuit without the intervention of the control system  1 . Therefore, when the cutoff lever  372  is in the “down position”, the operation unit  35 &#39;s operation drives the drive unit  34 , whereas when the cutoff lever  372  is in the “up position,” the output of the drive unit  34  is forcibly stopped regardless of the operation unit  35 &#39;s operation. Therefore, to drive the drive unit  34 , the user (operator) needs to operate the cutoff lever  372  to the “down” position. 
     Further, each of the swivel unit  32  and the travel unit  31  is also moved with the hydraulic oil supplied from the hydraulic pump to the hydraulic actuator (hydraulic motor); therefore, the cutoff lever  372  being in the “up position” disables the swivel unit  32  and travel unit  31 . That is, when the cutoff lever  372  is in the “up position,” the work unit  33 , the swivel unit  32 , and the travel unit  31  are all forcibly disabled. 
     In short, the cutoff switch  371 , when being off, is in a “locked state” in which the movement of the work machine  3  is restricted (including prohibition), and when being on, is in an “unlocked state” in which the movement of the work machine  3  is not restricted. Then, the cutoff lever  372  being in the “up position” and the cutoff switch  371  being in the locked state (off) forcibly restrict the movement of the work machine  3  including the drive unit  34 , regardless of the operation unit  35 &#39;s operation. The cutoff lever  372  is a lever that is operated for locking the movement of the work machine  3  in the above manner, and is synonymous with a gate (type) lock lever. 
     In addition to the above configuration, the machine body  30  is further provided with a communication terminal, a fuel tank, a battery, and the like. Further, the machine body  30  is provided with various sensors (including cameras) for detecting a to-be-detected object in a monitor area around the work machine  3 , such as a camera for capturing an image around the machine body  30 . 
     [2] Operation Unit 
     Next, the configuration of the operation unit  35  is described in detail with reference to  FIG.  3   . The operation unit  35  includes a pair of operation levers  351 ,  352  as described above. As shown in the “front view” in  FIG.  3   , the operation lever  351  is placed on the right hand side as seen from the user (operator) boarding the drive unit  321 , and the operation lever  352  is placed on the left hand side as viewed from the user boarding the drive unit  321 . Therefore, the user, for example, holds the operation lever  351  with the right hand and the operation lever  352  with the left hand, and operates the pair of operation levers  351 ,  352 , thereby causing the work machine  3  to execute various movements such as moving forward and backward. 
     Here, so to make the plurality of output ports  341  to  344  of the drive unit  34  individually operable, the operation unit  35  has a plurality (here four) of operants Sw 1  to Sw 4  that correspond to the plurality of output ports  341  to  344  on one-to-one basis. The operant Sw 1  is placed on the front side (front face) of the operation lever  351 , and the operant Sw 2  is placed on the front side (front face) of the operation lever  352  (see  FIG.  3   ). The operant Sw 4  is placed on the rear side (rear face) of the operation lever  351 , and the operant Sw 3  is placed on the rear side (rear face) of the operation lever  352  (see  FIG.  3   ). That is, in the present embodiment, the right-hand side operation lever  351  has the operants Sw 1  and Sw 4  divided into its front and rear faces, and the left-hand side operation lever  352  has the operants Sw 2  and Sw 3  divided into its front and rear faces. The plurality of operants Sw 1  to Sw 4  constitute “adjusting operants” that adjust the magnitude (flowrate of hydraulic oil) of the power output from the drive unit  34 . 
     As one example in the present embodiment, each of the operants Sw 1  to Sw 4  includes a lever switch that can be operated to tilt in a right direction A 1  and a left direction A 2 . In particular, each of the operants Sw 1  to Sw 4  is a momentary type switch that has the movable range&#39;s center in the right/left direction D 3  as a neutral position Pn 1  (see  FIG.  3   ), tilts in the right direction A 1  or left direction A 2  with an operating force being operated, and return to the neutral position Pn 1  with the operating force lost. Being operated to the right direction A 1  or the left direction A 2 , respectively, the above operants Sw 1  to Sw 4  determine, according to the operation volume (tilt volume) thereof, the magnitude of the power (flowrate of the hydraulic oil) output from the corresponding output ports  341  to  344 . Basically, the larger the operation volume of the operants Sw 1  to Sw 4 , the larger the power output from the respectively corresponding output ports  341  to  344 , i.e., the larger the flowrate of hydraulic fluid. 
     As an example here, it is assumed that the operant Sw 1  corresponds to the output port  341 , the operant Sw 2  corresponds to the output port  342 , the operant Sw 3  corresponds to the output port  343 , and the operant Sw 4  corresponds to the output port  344 . In this case, with the user operating the operant Sw 1 , the power output from the output port  341  in the drive unit  34  is adjusted according to the operation volume of the operant Sw 1 . Meanwhile, with the user operating the operant Sw 4 , the power output from the output port  344  in the drive unit  34  is adjusted according to the operation volume of the operant Sw 4 . The correspondence between the output ports  341  to  344  and of the operants Sw 1  to Sw 4  are defined by “allocation information”, which is stored in a memory of the control system  1 , for example. 
     Although a detailed description is omitted, setting for the operation unit  35 &#39;s operation, such as the allocation information (correspondence between the output ports  341  to  344  and the operants Sw 1  to Sw 4 ), is done on the display unit  2 , for example. That is, in the setting screen, etc. displayed on the display portion  23  of the display unit  2 , the operation by the user can set the correspondence between the output ports  341  to  344  and the operants Sw 1  to Sw 4 . 
     In the present embodiment, an operant Sw 5  is placed on the rear side (rear face) of the operation lever  351 , and an operant Sw 6  is placed on the rear side (rear face) of the operation lever  352 . The operants Sw 5  and Sw 6  are for enabling (on) a maintaining function (hold function) for maintaining the output of the drive unit  34 . That is, the operants Sw 5  and Sw 6  include “maintaining operants” for maintaining the output of the drive unit  34 . As one example in the present embodiment, each of the operants Sw 5  and Sw 6  is a momentary type push button switch. 
     Therefore, the user, when pressing the operants Sw 5  and Sw 6 , enables the maintaining function, thus maintaining the output of the drive unit  34 . 
     In particular, in the present embodiment, the operant Sw 5  provided at the operation lever  351  enables the maintaining function for the output port  341  that corresponds to the operant Sw 1  provided at the same operation lever  351 . Meanwhile, the operant Sw 6  provided at the operation lever  352  enables the maintaining function for the output port  342  that corresponds to the operant Sw 2  provided at the same operation lever  352 . So, for example, the user, when pressing the operant Sw 5 , maintains (holds) the output for the output port  341  out of the plurality of output ports  341  to  344 . 
     However, not limited to the above configuration, it is sufficient that the operant Sw 5  should correspond to at least one of the output ports  341  and  344  that correspond to the operants Sw 1  and Sw 4  provided at the same operation lever  351 , whereas the operant Sw 6  should correspond to at least one of the output ports  342  and  343  that correspond to the operants Sw 2  and Sw 3  provided at the same operation lever  352 . So, the operant Sw 5 , for example, may enable the maintaining function for both of the output ports  341  and  344 , and may enable the maintaining function for the output port  344 . Meanwhile, the operant Sw 6  may enable the maintaining function for both of the output ports  342  and  343 , and may enable the maintaining function for the output port  343 . 
     In short, in the work machine  3  according to the present embodiment, the drive unit  34  moves according to the operation for the operation unit  35  having the operants Sw 1  Sw 6 . Here, the operants Sw 1  to Sw 6  include the adjusting operants (operants Sw 1  to Sw 4 ) for adjusting the output of the drive unit  34 , and the maintaining operants (operants Sw 5 , Sw 6 ) for maintaining the output of the drive unit  34 . Further, a plurality of adjusting operands (operants Sw 1  and Sw 4 ) is provided for the one operation lever  351 , whereas a plurality of adjusting operands (operants Sw 2  and Sw 3 ) is provided for the one operation lever  352 . 
     Here, when the adjusting operants (operants Sw 1  to Sw 4 ) and the maintenance operants (operants Sw 5 , Sw 6 ) are simultaneously operated, the work machine  3  maintains the output of the drive unit  34  at a value that corresponds to the operation volume of the adjusting operants (operants Sw 1  to Sw 4 ). For example, the user pressing the operant Sw 5  while operating the operant Sw 1  simultaneously operates the adjusting operant (Sw 1 ) and the maintaining operant (Sw 5 ). In this case, the magnitude of the power output from the output port  341  is maintained at a value that corresponds to the operant Sw 1 &#39;s operation volume seen at the time when the operant Sw 5  is operated. 
     Meanwhile, when the maintaining operants (operants Sw 5 , Sw 6 ) out of the adjusting operants (operants Sw 1  to Sw 4 ) and the maintaining operants (operants Sw 5 , Sw 6 ) are operated, the work machine  3  maintains the output of the drive unit  34  at a specified value. For example, when the user presses only the operant Sw 5 , the magnitude of the power output from the output port  341  that corresponds to the operant Sw 1  is maintained at the specified value preset for output port 
     Therefore, depending on how the user operates, it is possible to easily distinguish between maintaining the output of the drive unit  34  at an arbitrary value and maintaining the output of the drive unit  34  at a specified value. Hereafter, the maintaining function&#39;s movement state seen when maintaining the output of drive unit  34  at the arbitrary value is referred to as “arbitrary hold,” and the maintaining function&#39;s movement state seen when maintaining the output of drive unit  34  at the specified value is referred to as “specified value hold”. 
     Further, in the present embodiment, as shown in  FIG.  3   , each of the operation levers  351 ,  352  has a grip portion provided with a display light  350  to present the movement state of the maintaining function. The display light  350  includes a light-emitting element, such as an LED, for example, and presents the movement state of the maintaining function by its light-emitting state (lighting state). 
     Each of the operants Sw 1  to Sw 4  is not limited to the lever switch, but may be, for example, a toggle switch, a rocker switch, a rotary switch, a slide switch, or an encoder. Each of the operants Sw 5  and Sw 6  as well is also not limited to the push-button switch, but may be a lever switch or a touch sensor, for example. The operation levers  351 ,  352  may be reversed on right and left, or may be placed side by side in the forward/backward direction D 2  or the upper/lower direction D 1 . The operation lever may be only one of the operation levers  351 ,  352 . 
     Further, placing of the operants Sw 5 , Sw 6  is not limited to on the rear sides of the operation levers  351 ,  352 , but may be on the sides or front sides of the operation levers  351 ,  352 . At the operation levers  351 ,  352  described above, the operation unit  35  may have a plurality of operants other than the above operants Sw 1  to Sw 6 . The display light  350  can also be omitted as proper. 
     [3] Configuration of Control System 
     Next, a configuration of the control system  1  according to the present embodiment will be described with reference to  FIG.  2   . The control system  1  controls various portions of the machine body  30  (including travel unit  31 , swivel unit  32 , work unit  33 , and drive unit  34 , etc.) according to the operation for the operation unit  35 . In the present embodiment, the operation unit  35  is installed on the machine body  30  of the work machine  3 , as described above. The control system  1  is a component of the work machine  3 , and constitutes the work machine  3  together with the machine body  30  and the like. In other words, the work machine  3  according to the present embodiment has at least the control system  1  and the machine body  30  which is controlled according to the operation for the operation unit  35 . 
     As shown in  FIG.  2   , the control system  1  is equipped with an acquisition processing unit  11 , a monitor processing unit  12 , a determination processing unit  13 , a switch processing unit  14 , a control processing unit  15 , and a notification processing unit  16 . As one example in the present embodiment, the control system  1  is mainly composed of a computer system having one or more processors; therefore executing a work machine control program by the one or more processors realize a plurality of function units (acquisition processing unit  11  and the like). The plurality of function units included in the control system  1  may be distributed to a plurality of cases or may be included in a single case. 
     The control system  1  is so configured as to be communicable with a device provided in each unit of the machine body  30 . That is, to the control system  1 , at least the display unit  2 , the operation unit  35 , the control valve  36 , the cutoff switch  371  and the like are connected. This allows the control system  1  to control the display unit  2 , the control valve  36 , etc., and to acquire electric signals (operation signals, etc.) from the display unit  2 , the operation unit  35 , and the cutoff switch  371 . Being “communicable” referred to in the present disclosure means that information (data) can be sent and received either directly by a proper communication method of a wired communication or wireless communication (communication using a radio wave or light as a medium), or indirectly via a communication network (a network), a relay or the like. Therefore, the control system  1  may send and receive various types of information (data) directly to and from each device, or indirectly via the relay or the like. The control system  1  can communicate with the device provided in each unit of the machine body  30  using a communication method such as CAN (Controller Area Network) or the like, as an example. 
     The acquisition processing unit  11  executes an acquiring process that accepts the operation for the operation unit  35  for controlling the work machine  3 . That is, the operation unit  35  having a plurality of operants Sw 1  to Sw 6  outputs an operation signal that accords to the operation by the user, thereby causing the acquisition processing unit  11  to acquire the above operation signal. This makes it possible, for the operant Sw 1  out of the operants Sw 1  to Sw 6 , for example, that the acquisition processing unit  11  should acquire the operation signal representing the operation volume for the neutral position Pn 1 . 
     The monitor processing unit  12  executes a monitoring process to monitor a specific event to be monitored. The “specific event” in the present disclosure is a predetermined specific event, and the monitor processing unit  12  monitors whether or not the specific event has occurred. That is, when the specific event occurs, the monitor processing unit  12  detects the occurrence of the specific event. 
     In the present embodiment, the specific event includes an event that involves a change in the work machine  3 &#39;s movement state that corresponds to the operation unit  35 &#39;s operation. That is, the specific event includes an event that causes some change in the movement state of the work machine  3 , despite the operation for the operation unit  35  being constant (fixed). With this configuration, the occurrence of an event where the movement state of the work machine  3  is suddenly changed while the user (operator) is maintaining the operation state of the operation unit  35  can be detected, as the occurrence of the specific event, by the monitor processing unit  12 . This makes it possible to detect an event, which leads to sudden driving of the work machine  3  or sudden stopping of the work machine  3 , for example, as the occurrence of the specific event. 
     Specifically, in the present embodiment, the specific event includes the switching of the cutoff switch  371  in the work machine  3 , from the locked state (off) to the unlocked state (on). That is, switching from the cutoff switch  371  in the locked state (off) with the cutoff lever  372  in the “up position” to the cutoff switch  371  in the unlocked state (on) with the cutoff lever  372  operated in the “down position” is included in the specific event. With this; while the user has operated the operation unit  35 , for example, the monitor processing unit  12  can detect, as the occurrence of the specific event, the sudden driving of the work machine  3  in accordance with the cutoff switch  371  being switched from the locked state to the unlocked state. 
     The specific event also includes a change in the setting for the operation unit  35 &#39;s operation. That is, changing of the setting for the operation unit  35 &#39;s operation, for example, changing of the “allocation information” that defines the correspondence between the output ports  341  to  344  and the operants Sw 1  to Sw 4  is included in the specific event. With this; while the user is operating the operant Sw 1 , as an example, the monitor processing unit  12  can detect, as the occurrence of the specific event, the sudden driving of output port  342  in accordance with the allocation information for the operant Sw 1  being changed from the output port  341  to the output port  342 . 
     When the specific event occurs, the determination processing unit  13  executes a determination process to determine whether or not a determination condition for the operation for the operation unit  35  is met. The “determination condition” in the present disclosure is a condition predetermined in relation to the operation for the operation unit  35 , such as, for example, that each of the operants Sw 1  to Sw 4  is positioned in the neutral position Pn 1 , that the operants Sw 5 , Sw 6  are not operated, or a specific operator is pressed for a long time (operated continuously for a predetermined period or longer). 
     Based on the result of the determination as to whether or not the determination condition is met, the switch processing unit  14  switches, between enabled and disabled, the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation. When the work machine  3 &#39;s control which corresponds to the operation unit  35 &#39;s operation is “disabled”, the drive unit  34  becomes inoperable, for example, forcibly stopping the output of the drive unit  34 , regardless of the operation unit  35 &#39;s operation. As one example in the present embodiment, the switch processing unit  14 , with the determination condition being met, enables the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation, and with the determination condition not met, disables the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation. 
     The control processing unit  15  executes the control process to control the machine body  30  in response to the operation unit  35 &#39;s operation. In the control process, the control processing unit  15  controls the travel unit  31 , swivel unit  32 , and work unit  33 , etc. of the machine body  30 . Specifically, the control processing unit  15  outputs a control signal to the control valve  36  in response to the operation of at least the operation unit  35 , thereby to control the drive unit  34 . 
     The notification processing unit  16  executes a notifying process that provides a notification which is based on the result of the determination as to whether or not the determination condition is met. “The notification” as used in the present disclosure means a notification to the user (operator) by various measures, including, for example, display (including lighting of display light), sound (including voice), sending to another terminal, or writing in a non-transient recording medium. As one example in the present embodiment, the notification processing unit  16 , with the determination condition not met, that is, with the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation “disabled”, causes the display portion  23  of the display unit  2  to display a message to that effect, thereby providing a notification that is based on the determination result (see  FIG.  7   ). 
     [4] Work Machine Control Method 
     Hereinafter, an example of a method of controlling the work machine  3  (hereinafter, simply referred to as a “control method”) executed mainly by the control system  1  will be described with reference to  FIG.  5    to  FIG.  7   .  FIG.  5    is a flowchart showing an example of a process according to the control method.  FIG.  6    shows an example of state changes of cutoff signal, PTO operation, and PTO control, with the horizontal axis as a time axis. The “cutoff signal” here is an electric signal input from the cutoff switch  371  to the control system  1 , showing off (locked state) or on (unlocked state) of the cutoff switch  371 . The “PTO operation” here is an electric signal (operation signal) input from the operation unit  35  to the control system  1 , showing, in particular, operation states of the operants Sw 1  to Sw 4  for operating the output ports  341  to  344  of the drive unit  34 . The “PTO control” is the state of control by an electric signal (control signal) output from the control system  1  to the control valve  36 , showing, in particular, whether the control of the output ports  341  to  344  of the drive unit  34  is enabled or disabled. 
     The control method according to the present embodiment is executed by the control system  1  mainly constituted by the computer system, and in other words, is embodied by a work machine control program (hereinafter, simply referred to as “control program”). That is, the control program according to the present embodiment is a computer program that causes one or more processors to execute various processes that accord to the control method. The above control program may be cooperatively executed by, for example, the control system  1  and the display unit  2 . 
     Here, when a specific start operation set in advance so as to cause the control program to be executed, the control system  1  executes the following various types of processes that accord to the control method. Examples of the start operation include an operation of starting the engine of the work machine  3 . Meanwhile, when a specific termination operation set in advance is executed, the control system  1  terminates the various types of processes that accord to the control method. Examples of the termination operation include an operation of stopping the engine of the work machine  3 . 
     As one example, the following describes the control method seen when defining an initial state as a state where the cutoff lever  372  is in the “up position” and the cutoff switch  371  is in the locked state (off). Further, with the cutoff switch  371 &#39;s switching from the locked state (off) to the unlocked state (on) used as an example of the “specific event,” the description will be made with each of the operants Sw 1  to Sw 4  being in the neutral position Pn 1  as an example of the “determination condition. 
     As shown in  FIG.  5   , the control system  1  first acquires a cutoff signal from the cutoff switch  371  (S 1 ). Here, in the initial state, the cutoff lever  372  is in the “up position” as described above, thus bringing the cutoff signal in the locked state. Then, from the cutoff signal, the monitor processing unit  12  of the control system  1  determines whether or not the cutoff switch  371  is in the unlocked state. (S 2 ). While the cutoff lever  372  is kept in the “up position,” the cutoff signal is locked; therefore, the monitor processing unit  12  determines that the unlocked state is not made (S 2 : No), and returns the process to step S 1 . Meanwhile, the user lowering the cutoff lever  372  thereby to move the cutoff lever  372  to the “down position” brings the cutoff signal in the unlocked state; therefore, the monitor processing unit  12  determines that the unlocked state is made (S 2 : Yes), and moves the process to step S 3 . At this time, with the cutoff switch  371  switched from the locked state (off) to the unlocked state (on), the monitor processing unit  12  determines that the “specific event” has occurred. 
     In step S 3 , the acquisition processing unit  11  of the control system  1  acquires an operation signal from the operation unit  35 . At this time, the acquisition processing unit  11  acquires, as the PTO operation, the operation state of the operants Sw 1  to Sw 4  for operating the output ports  341  to  344  of the drive unit  34 . In step S 4 , the determination processing unit  13  of the control system  1  determines whether or not the operants Sw 1  to Sw 4 &#39;s operation state (PTO operation) identified from the operation signal is in the neutral position Pn 1  (not limited to a pinpoint, but may be a predetermined range including play). The operants Sw 1  to Sw 4  are momentary type switches that return to the neutral position Pn 1  when the operating force is lost. Therefore, the determination processing unit  13  determines that, when being operated by the user, at least one of the operants Sw 1  to Sw 4  is not in the neutral position Pn 1  (S 4 : No), then moves the process to step S 5 . Meanwhile, the determination processing unit  13  determines that, when not being operated by the user, any of the operants Sw 1  to Sw 4  is in the neutral position Pn 1  (S 4 : Yes), then moves the process to step S 6 . At this time, with all of the operants Sw 1  to Sw 4  in the neutral position Pn 1 , the determination processing unit  13  determines that the “determination condition” is met. 
     In step S 5 , the switch processing unit  14  of the control system  1  disables the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation. As one example in the present embodiment, the switch processing unit  14  disables the control of the output ports  341  to  344  of the drive unit  34  (PTO control), which control accords to the operation (PTO operation) of the operants Sw 1  to Sw 4 , thereby disabling the work machine  3 &#39;s control. This forcibly stops the output for all of the output ports  341  to  344  of the drive unit  34 , regardless of the actual operation volume of the operants Sw 1  to Sw 4 . 
     In step S 6 , the switch processing unit  14  of the control system  1  enables the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation. As one example in the present embodiment, the switch processing unit  14  enables the control of the output ports  341  to  344  of the drive unit  34  (PTO control), which control accords to the operation (PTO operation) of the operants Sw 1  to Sw 4 , thereby enabling the work machine  3 &#39;s control. This makes it possible to control the output of each of the output ports  341  to  344  of the drive unit  34 , according to the actual operation volume of the operants Sw 1  to Sw 4 . 
     Then, in step S 7 , the acquisition processing unit  11  of the control system  1  acquires an operation signal from the operation unit  35 . At this time, the acquisition processing unit  11  acquires, as the PTO operation, the operation state of the operants Sw 1  to Sw 4  for operating the output ports  341  to  344  of the drive unit  34 . In step S 8 , the control processing unit  15  of the control system  1  determines whether or not the operants Sw 1  to Sw 4 &#39;s operation state (PTO operation) identified from the operation signal is in the neutral position Pn 1 . The control processing unit  15  determines that, when being operated by the user, at least one of the operants Sw 1  to Sw 4  is not in the neutral position Pn 1  (S 8 : No), then moves the process to step S 9 . Meanwhile, the control processing unit  15  determines that, when not being operated by the user, any of the operants Sw 1  to Sw 4  is in the neutral position Pn 1  (S 8 : Yes), then returns the process to step S 7 . 
     In step S 9 , according to the operants Sw 1  to Sw 4 &#39;s operation state (PTO operation) identified from the operation signal, the control processing unit  15  of the control system  1  outputs the control signal to the control valve  36 , thereby to execute the PTO control for controlling the output ports  341  to  344  of the drive unit  34 . With step S 9 , the series of processes related to the control method is completed. 
     Whenever the cutoff lever  372  is operated to the “up position” thereby to bring the cutoff switch  371  in the locked state (off), the control system  1  executes the above processes in steps S 1  to S 9 . The flowchart shown in  FIG.  5    is merely an example, and any process may be added or omitted as proper, or the sequence of processes may be swapped as proper. 
     According to the series of processes described above, the control signal will be switched between enabled and disabled, as shown in  FIG.  6   . That is, in a period up to a time point t 1 , the cutoff lever  372  is in the “up position” and the cutoff signal is locked (off). Therefore, during the period up to time point t 1 , the PTO control is “disabled”; therefore, the drive unit  34  is not controlled even when the operants Sw 1  to Sw 4  are operated from the neutral position Pn 1  thereby to bring the PTO operation in the “operation” state. That is, regardless of the actual operation volume of the operants Sw 1  to Sw 4 , outputting is forcibly stopped for all of the output ports  341  to  344  of the drive unit  34 . As one example in the present embodiment, when the cutoff signal is in the locked state (off), the control signal is turned off so that no extra power consumption is caused by the control signal, but the present invention is not limited to the above configuration. That is, when the cutoff signal is in the locked state (off); in the first place, it is not so made that the hydraulic circuit is cut off thereby to drive the drive unit  34 . Therefore, even when the control signal is not turned off, the drive unit  34  is forcibly stopped. 
     Meanwhile, when the user operates the cutoff lever  372  to the “down position” at the time point t 1 , the cutoff signal is unlocked (on). That is, at the time point t 1 , the “specific event” occurs in which the cutoff switch  371  switches from the locked state (off) to the unlocked state (on). However, at the time point t 1 , the PTO operation is in the “operation” state, not in the neutral position Pn 1 , thus failing to meet the “determination condition”. Therefore, during the period from the time point t 1  to a time point t 2 , the PTO control is “disabled”; therefore, the drive unit  34  is not controlled even when the operants Sw 1  to Sw 4  are operated from the neutral position Pn 1  thereby to bring the PTO operation in the “operation” state. That is, regardless of the actual operation volume of the operants Sw 1  to Sw 4 , outputting is forcibly stopped for all of the output ports  341  to  344  of the drive unit  34 . 
     At the time point t 2 , the user stops operating all of the operants Sw 1  to Sw 4  operants, thereby to bring all of the operants Sw 1  to Sw 4  in the neutral position Pn 1 , thus bringing the PTO operation in the “non-operation” state. That is, at the time point t 2 , all of the operants Sw 1  to Sw 4  being in the neutral position Pn 1  meet the “determination condition”. Due to this, at the time point t 2 , the PTO control is switched to “enable”. Therefore, at a time point t 3  after the time point t 2 , operating the operants Sw 1  to Sw 4  from the neutral position Pn 1  thereby to bring the PTO operation in the “operation” state controls the drive unit  34 . That is, in the period after the time point t 2 , the outputs of the output ports  341  to  344  of the drive unit  34  are controlled according to the actual operation volume of the operants Sw 1  to Sw 4 . 
     In the present embodiment, when the PTO control is “disabled”, not only is the drive unit  34 &#39;s drive that corresponds to the operation of the adjusting operants (operants Sw 1  to Sw 4 ), but also the drive unit  34 &#39;s drive that corresponds to the operation of the maintaining operants (operants Sw 5 , Sw 6 ) is not driven. That is, even when the operation to drive the drive unit  34  is executed by the “specified value hold” function, output of the drive unit  34  is forcibly stopped with the PTO control being “disabled”. 
     As described above, the control method according to the present embodiment has the following operations: accepting the operation for the operation unit  35  for controlling the work machine  3 , monitoring the specific event to be monitored, and determining, the specific event occurring, whether or not the determination condition for the operation for the operation unit  35  is met. In short, in the example of  FIG.  6   , it is so determined that, when the cutoff switch  371  switches from the locked state to the unlocked state at the time point t 1  (step S 2  in  FIG.  5   : Yes), the “specific event” has occurred. In this case, it is so determined, for example, that after the time point t 1 , the “determination condition” is met with all of the operants Sw 1  to Sw 4  in the neutral position Pn 1 , (step S 4  in  FIG.  5   : Yes). 
     With this configuration, when the cutoff switch  371  is switched from the locked state to the unlocked state, for example, it is determined whether or not the determination condition for the operation for the operation unit  35  is met. Therefore, by notifying the user (operator) of the determination results, for example, the operator can prepare for a sudden movement of the work machine  3 , thereby easily reducing a burden on the operator for the operation. 
     The control method according to the present embodiment further has switching, between enabled and disabled, the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation, based on the result of the determination as to whether or not the determination condition is met. This means that, when the cutoff switch  371  is switched from the locked state to the unlocked state, for example, the work machine  3 &#39;s control is automatically switched between enabled and disabled according to whether or not the determination condition for the operation for the operation unit  35  is met. Therefore, it is possible to avoid the sudden movement of the work machine  3  without the user (operator) having to make a careful operation. 
     Here, in the present embodiment, the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation is enabled with the determination condition determined to be met after the occurrence of the specific event. That is, meeting the determination condition after the occurrence of the specific event automatically enables the work machine  3 &#39;s control. Therefore, it is possible to avoid the sudden movement of the work machine  3  without the user (operator) having to make a careful operation. 
     In the present embodiment, the operation for the operation unit  35  includes an operation to control the output of the PTO ports (output ports  341  to  344 ) of the work machine  3 . With this, it is possible to prevent the output of the PTO ports (output ports  341  to  344 ) of the work machine  3  from suddenly occurring, when the cutoff switch  371  is switched from the locked state to the unlocked state, for example. 
     By the way, with the control method according to the present embodiment, as exemplified in  FIG.  7   , a notification based on the result of the determination as to whether or not the determination condition is met is done on the display screen Dp 1  displayed on the display portion  23  of the display unit  2 . The “screen”, such as the display screen Dp 1  in the present disclosure, means an image (picture) displayed on the display unit  2 , and includes figures, graphics, photographs, text, and moving images. Here, when the display screen Dp 1  includes a moving image or the like, the display screen Dp 1  does not include a constant image but includes an image that changes from moment to moment. In the drawing showing the display screen Dp 1  displayed on the display portion  23  of the display unit  2  as in  FIG.  7   , the dotted lines representing areas, the leading lines, and the reference codes are each only for illustration, and are not actually displayed on the display unit  2 . 
     As one example in the present embodiment, the notification processing unit  16  of the control system  1 , when the determination condition is not met, that is, when the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation is “disabled”, displays a message M 1  on the display screen Dp 1 , as shown in  FIG.  7   . In the present embodiment, the switch processing unit  14 , when having disabled the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation (step S 5  in  FIG.  5   ), provides a notification by the notification processing unit  16  displaying the message M 1 . The message M 1  is so displayed as to pop up in a manner to superimpose on another display on the display screen Dp 1 , for example, and includes a text, such as “PTO control: disabled”, showing that the work machine  3 &#39;s control (herein, PTO control) is “disabled”. In addition, the message M 1  includes a text, such as “For enabling, please once put the switch back in neutral”, showing a procedure for enabling the work machine  3 &#39;s control (herein, PTO control). 
     In the present embodiment, the above message M 1  is displayed only while the work machine  3 &#39;s control is “disabled”. Therefore, the switch processing unit  14  of the control system  1 , when enabling the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation ( FIG.  5   , step S 6 ), deletes the message M 1 . The display mode of the notification based on the result of the determination as to whether or not the determination condition is met is not limited to the message M 1 . For example, it may be so made that, as well as an icon Im 1  showing on/off of the cutoff switch  371 , an icon displayed on the display screen Dp 1  may provide the notification that is based on the result of the determination as to whether or not the determination condition is met. 
     Thus, the control method according to the present embodiment further has the following: providing a notification that is based on the result of the determination as to whether or not the determination condition is met. This allows the user (operator) to know whether the work machine  3 &#39;s control is currently “enabled” or “disabled”, and to operate the operation unit  35  on that basis. The notification of the determination result is not limited to the above configuration that is executed only when the determination condition is not met, i.e., when the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation is “disabled”, as described above. That is, the notification of the determination result may be a notification that can distinguish whether or not the determination condition is met; for example, the notification of the determination result may be provided when the determination condition is met, that is, when the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation is “enabled”. Further, the fact that the work machine  3 &#39;s control is “disabled” may be notified when the determination condition is not met, that is, when the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation is “disabled,” and only when the operation unit  35  is operated. 
     [5] Other Functions 
     The “specific event” is not limited to the cutoff switch  371  switching from the locked (off) to the unlocked (on). Similarly, the “determination condition” is not limited to each of the operants Sw 1  to Sw 4  being positioned in the neutral position Pn 1 . In addition, the control that is switched between enabled and disabled by the switch processing unit  14  is not limited to the output control (PTO control) of the PTO ports (output ports  341  to  344 ) of the work machine  3 . 
     That is, the “specific event” may be, for example, a change of the setting for the operation unit  35 &#39;s operation, such as a change in the “allocation information” that defines the correspondence between the output ports  341  to  344  and the operants Sw 1  to Sw 4 . In this case, the specific event will occur, for example, when the setting for the operation unit  35 &#39;s operation, such as allocation information, is changed by the user&#39;s operation for the display unit  2 . Here, the setting for the operation unit  35 &#39;s operation is not limited to the setting of the correspondence between the output ports  341  to  344  and the operants Sw 1  to Sw 4 , but also includes setting for the correspondence between the operation unit  35 &#39;s operation and the flowrate of the hydraulic fluid, etc. 
     When the control that is switched between enabled and disabled by the switch processing unit  14  is, for example, a control of the travel unit  31 , swivel unit  32  or work unit  33 , other than the PTO control, changing of the correspondence between the operations of the operation levers  351 ,  352  and a movement of the travel unit  31 , swivel unit  32  or work unit  33  may be included in the specific event. Further, a change in a movement pattern of the travel unit  31 , swivel unit  32  or work unit  33  in response to the operations of the operation levers  351 ,  352  can also be included in the specific event. In this case, the “determination condition” is that the operation levers  351 ,  352 , not each of the operants Sw 1  to Sw 4 , are in the neutral position. 
     In addition, the control that is switched between enabled and disabled by the switch processing unit  14  may include a quick hitch control for attaching and detaching the attachment  331  to and from the machine body  30 . In this case, for example, instead of the cutoff switch  371  switching from locked to unlocked, switching, from off to on, of the power switch for enabling a movement of the quick hitch may be included in the specified event. With this; while the user (operator) has opened the quick hitch, for example, the monitor processing unit  12  can detect, as the occurrence of the specific event, the occurrence of such an event as to suddenly drive the quick hitch in accordance with the power switch being switched from on to off. 
     [6] Modified Example 
     A description will hereinafter be made on a modified example of the first embodiment. The modified example, which will be described below, can be applied in a proper combination. 
     The control system  1  according to the present disclosure includes the computer system. The computer system has, as hardware, one or more processors and one or more memories. Executing the program recorded in the memory of the computer system, the processor realizes the function as the control system  1  in the present disclosure. The program may be preliminarily recorded in the memory of the computer system, may be provided through an electric communication line, or may be may be provided in a manner to be recorded in a non-transitory recording medium, such as a memory card, an optical disk, a hard disk drive, or the like, each of which is readable by the computer system. Further, a part of or all of the function units included in the control system  1  may be composed of an electronic circuit. 
     A configuration in which at least a part of the functions of the control system  1  is integrated in one case is not essential for the control system  1 , and the components of the control system  1  may be provided in a plurality of cases in a distributed manner. Conversely, functions that are distributed to a plurality of devices (such as the control system  1  and the display unit  2 ) in the first embodiment may be integrated in one case. Further, at least a part of the functions of the control system  1  may be realized by a cloud (cloud computing) or the like. 
     Further, the power source of the work machine  3  is not limited to the diesel engine, but may be, for example, an engine other than the diesel engine, a motor (an electric motor), or a hybrid power source that includes the engine and the motor (an electric motor). 
     The drive unit  34  is not limited to the PTO (power take-off) or other device to take out the power (as power for driving the attachment  331 ) from the engine, but may also be a device that outputs, separately from the engine, the power for driving the attachment  331 . Further, the drive unit  34  is not limited to the device that supplies power to the attachment  331  by supplying hydraulic fluid, but may also be a device that generates power by an electric motor such as a motor. In this case, the power output from the drive unit  34  is controlled by, for example, the current flowing through the drive unit  34 . 
     The attachment  331  only needs to be attached to the machine body  30 , and the attachment  331 &#39;s detachably being attached to the machine body  30  is not an essential configuration. In addition, a plurality of attachments  331  may be attached to the machine body  30  at the same time. 
     Further, the display unit  2  is not limited to a dedicated device, but may be a general-purpose terminal, such as a laptop computer, a tablet terminal, or a smartphone. Further, the display portion  23  is not limited to the mode of directly displaying the display screen Dp 1 , such as a liquid crystal display or an organic EL display, but may also be configured to display the display screen Dp 1  by projection, for example, as like a projector. The display area of the display portion  23  is not limited to being horizontally long, but may also be vertically long. 
     In addition, as the mode of inputting information of the operation portion  22 , any mode other than the push button switches  221  to  226 , the touch screen, and operation dial may also be employed. For example, the operation portion  22  may employ any mode such as a keyboard, a pointing device such mouse, a voice input, a gesture input, or inputting an operation signal from another terminal. 
     The operation unit  35 , the display unit  2 , etc. are not limited to having the configuration installed on the machine body  30 , but may be installed separately from the machine body  30 , for example. In this case, the operation unit  35  and the display unit  2 , etc., are configured to communicable with the machine body  30 , realizing a remote control the machine body  30 . 
     Second Embodiment 
     As shown in  FIG.  8   , in the timing for enabling the PTO control, the control method according to the present embodiment differs from the control system  1  according to the first embodiment. Hereinafter, the same components as those in the first embodiment will be denoted by the same reference signs, and the description thereof will properly be omitted. 
     A flowchart shown in  FIG.  8    differs from the flowchart shown in  FIG.  5    in omitting step S 6 , which enables the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation, and in adding step S 16 , to between step S 8  and step S 9 , that enables the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation. Other features are as described in the first embodiment, and therefore are omitted here. 
     That is, in the present embodiment, merely determining that the “determination condition” is met by the fact that all of the operants Sw 1  to Sw 4  in step S 4  are in the neutral position Pn 1  (S 4 : Yes) fails to immediately enable the work machine  3 &#39;s control (PTO control). That is, the work machine  3 &#39;s control (PTO control) is enabled (S 16 ) at the timing when it is determined that, after the determination of meeting the determination condition (S 4 : Yes), with the operation signal acquired afresh (S 7 ), at least one of the operants Sw 1  to Sw 4 , that is operated by the user, is not in the neutral position Pn 1  (S 8 : No). 
     In this example, until the user operates at least one of the operants Sw 1  to Sw 4  after the determination of meeting the determination condition, the work machine  3 &#39;s control (PTO control) is disabled, so the message M 1  as in  FIG.  7    will continue to be displayed. 
     Thus, in the present embodiment; the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation is enabled, with the determination condition determined to be met and further with the operation unit  35  operated, after the occurring of the specific event. With this, only when the user (operator) actually operates the operation unit  35 , in addition to meeting the determination condition, the work machine  3 &#39;s control that corresponds to the operation unit  35 &#39;s operation is enabled, thus making it easy to prevent the work machine  3  from moving due to an unintended operation by the operator. 
     The configuration according to the second embodiment can be employed in a proper combination with the various configurations (including the modified example) described in the first embodiment. 
     REFERENCE SIGNS LIST 
     
         
           1 : work machine control system 
           3 : work machine 
           11 : acquisition processing unit 
           12 : monitor processing unit 
           13 : determination processing unit 
           30 : machine body 
           35 : operation unit 
           371 : cutoff switch 
           341  to  344 : output port (PTO port)