US20220267998A1 - Construction machine - Google Patents

Construction machine Download PDF

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Publication number
US20220267998A1
US20220267998A1 US17/623,637 US202017623637A US2022267998A1 US 20220267998 A1 US20220267998 A1 US 20220267998A1 US 202017623637 A US202017623637 A US 202017623637A US 2022267998 A1 US2022267998 A1 US 2022267998A1
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US
United States
Prior art keywords
control
mode
obstacle
vehicle body
cancelation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
US17/623,637
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English (en)
Inventor
Shinji Nishikawa
Koji SHIWAKU
Shinjiro Yamamoto
Ryota KAMEOKA
Akihiro Narazaki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Construction Machinery Co Ltd
Original Assignee
Hitachi Construction Machinery Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Construction Machinery Co Ltd filed Critical Hitachi Construction Machinery Co Ltd
Assigned to HITACHI CONSTRUCTION MACHINERY CO., LTD. reassignment HITACHI CONSTRUCTION MACHINERY CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: NARAZAKI, AKIHIRO, KAMEOKA, Ryota, NISHIKAWA, SHINJI, SHIWAKU, Koji, YAMAMOTO, SHINJIRO
Publication of US20220267998A1 publication Critical patent/US20220267998A1/en
Pending legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/24—Safety devices, e.g. for preventing overload
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
    • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
    • B60R21/013—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting collisions, impending collisions or roll-over
    • B60R21/0134—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting collisions, impending collisions or roll-over responsive to imminent contact with an obstacle, e.g. using radar systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
    • B60R21/34—Protecting non-occupants of a vehicle, e.g. pedestrians
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/2025—Particular purposes of control systems not otherwise provided for
    • E02F9/2033—Limiting the movement of frames or implements, e.g. to avoid collision between implements and the cabin
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2221—Control of flow rate; Load sensing arrangements
    • E02F9/2232—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps
    • E02F9/2235—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps including an electronic controller
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/26—Indicating devices
    • E02F9/261—Surveying the work-site to be treated
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/26—Indicating devices
    • E02F9/261—Surveying the work-site to be treated
    • E02F9/262—Surveying the work-site to be treated with follow-up actions to control the work tool, e.g. controller
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
    • B60R2021/0065—Type of vehicles
    • B60R2021/0074—Utility vehicles
    • B60R2021/0081—Working vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
    • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
    • B60R2021/01286—Electronic control units
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
    • E02F3/36—Component parts
    • E02F3/42—Drives for dippers, buckets, dipper-arms or bucket-arms
    • E02F3/43—Control of dipper or bucket position; Control of sequence of drive operations
    • E02F3/435—Control of dipper or bucket position; Control of sequence of drive operations for dipper-arms, backhoes or the like
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2246—Control of prime movers, e.g. depending on the hydraulic load of work tools
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2278—Hydraulic circuits
    • E02F9/2296—Systems with a variable displacement pump

Definitions

  • the present invention relates to a construction machine having a function to detect an obstacle (a person or an object) in the periphery of the vehicle body thereof and to limit operation of the vehicle body depending on the detected obstacle in order to reduce the possibility that the vehicle body and the obstacle in the periphery thereof contact each other.
  • an obstacle a person or an object
  • the construction machine may be unavoidable for the construction machine to operate with an obstacle (a person or an object), present in the periphery of the vehicle body thereof, such as when the construction machine should operate in environments where some kind of object (e.g., a gravel mound to be loaded onto a dump truck, an earth retaining wall, another construction machine, a dump truck, etc.) is present in the periphery of the construction machine, or when the construction machine should perform work with a worker placed in the periphery with the operator's and worker's consent.
  • an obstacle a person or an object
  • some kind of object e.g., a gravel mound to be loaded onto a dump truck, an earth retaining wall, another construction machine, a dump truck, etc.
  • the construction machine having a function to limit operation of its vehicle body when an obstacle in the periphery thereof is detected.
  • the construction machine includes means for allowing the operator to cancel the limitation on the operation.
  • the operator actuates the canceling means, the vehicle body can be moved as is the case with ordinary hydraulic excavators with the obstacle being detected.
  • Patent Document 1 discloses, as an invention relating to a method of canceling operation limitation, a construction machine that, when operation limitation is enabled upon detection of a person, allows predetermined operation in the cabin to cancel the limitation on operation and that changes the gradualness of returning from the limitation on operation depending on whether the obstacle is detected or not at the time the limitation on operation is to be canceled.
  • Patent Document 1 proposes a method that permits the operator to cancel operation limitation when an obstacle is detected, by making particular canceling operation, the method canceling the limitation on operation more safely by avoiding an abrupt velocity change upon cancelation.
  • Patent Document 1 Although the function to cancel operation limitation is referred to, situations where cancelation is required are treated as irregular, and no consideration has been made with respect to a way of permitting the construction machine to be used continuously with the limitation on operation being canceled.
  • Patent Document 1 refers to the method of canceling operation limitation, it does not clearly refer to a method of returning from a state where the limitation on operation is canceled to a normal state where vehicle body operation is limited upon detection of a person.
  • any situations where operation limitation is to be canceled do not essentially arise during normal work, and may be referred to as irregular.
  • irregular since current construction machines where the ability of a detecting function is under development are sufficiently assumed to work in situations where some kind of object is present in the periphery of the vehicle body, it is necessary for achieving both safety and operability to construct a driver assisting function based on the premise of using a construction machine in a manner of positively permitting situations where the construction machine operates with operation limitation being canceled.
  • a construction machine that is assumed to work in situations where some kind of object is present in the periphery of the vehicle body may detect an object that is required for work (e.g., a gravel mound to be loaded onto a dump truck) during normal work. Limiting operation of the vehicle body upon detection of such an object prevents the construction machine from performing well in originally intended use as a work machine, giving rise to the problem of a significant reduction in work performance.
  • an object that is required for work e.g., a gravel mound to be loaded onto a dump truck
  • the operator should effectively reinstate the limitation on operation each time it is required, depending on the environment in which the construction machine operates.
  • the operator forgets to take an operation to reinstate operation limitation another problem tends to arise in that the operator may take it for granted that the limitation on operation is enabled and may overlook a check around the construction machine.
  • the present invention has been made in order to solve the above problems. It is an object of the present invention to provide a construction machine that achieves both safety and operability by lowering the possibility of an accident due to contact between the construction machine and a worker in the periphery of the vehicle body while securing operability in situations where an object required for work is present in the periphery.
  • a construction machine including an actuator, an obstacle sensor for detecting an obstacle in a periphery of the construction machine, a controller for performing operation limiting control to limit operation of the actuator in a case where the obstacle sensor detects an obstacle, and a control canceling device for instructing the controller to cancel the operation limiting control.
  • the controller is configured to have a normal mode as a control mode for making the operation limiting control effective and a temporary cancelation mode as a control mode for temporarily canceling the operation limiting control, shift to the temporary cancelation mode in response to operation of the control canceling device while in the normal mode, and shift back to the normal mode in a case where a predetermined condition not responsive to operation of the control canceling device is satisfied while in the temporary cancelation mode.
  • the controller since the controller switches from the normal mode in which operation limitation is enabled to the temporary cancelation mode in which operation limitation is not enabled, in response to operation of the control canceling device, it is possible for the construction machine to secure operability in situations where an object required for work is present in the periphery of the vehicle body.
  • the controller when the predetermined condition not responsive to the operation of the control canceling device is satisfied while in the temporary cancelation mode, the controller returns to the normal mode independently of the operation of the control canceling device, making it possible to reduce the possibility of an accident due to contact between the construction machine and a worker in the periphery thereof.
  • the construction machine according to the present invention achieves both safety and operability by lowering the possibility of an accident due to contact between the construction machine and a worker in the periphery of the vehicle body while securing operability in situations where an object required for work is present in the periphery.
  • FIG. 1 is a view illustrating an appearance of a hydraulic excavator as an example of a construction machine according to a first embodiment of the present invention.
  • FIG. 2 is a view illustrating positions where obstacle sensors are installed and detection areas according to the first embodiment of the present invention.
  • FIG. 3 is a diagram illustrating a system configuration according to the first embodiment of the present invention.
  • FIG. 4 is a diagram illustrating the makeup of a controller for limiting operation of a vehicle body upon detection of an obstacle according to the first embodiment of the present invention.
  • FIG. 5 is a flowchart of a processing sequence of a detection determining section according to the first embodiment of the present invention.
  • FIG. 6 is a flowchart of a portion for determining an operation state with respect to each event of operation, of a processing sequence of an operation state determining section according to the first embodiment of the present invention.
  • FIG. 7 is a flowchart of a portion for determining an operated state with respect to the vehicle body, of the processing sequence of the operation state determining section according to the first embodiment of the present invention.
  • FIG. 8 is a flowchart of an entire processing sequence of a controlled state switching determining section according to the first embodiment of the present invention.
  • FIG. 9 is a flowchart of a processing sequence of a process of determining switching from a normal mode, as a subroutine of the controlled state switching determining section according to the first embodiment of the present invention.
  • FIG. 10 is a flowchart of a processing sequence of a process of determining switching from a temporary cancelation mode, as a subroutine of the controlled state switching determining section according to the first embodiment of the present invention.
  • FIG. 11 is a flowchart of a processing sequence of a process of determining switching from a permanent cancelation mode, as a subroutine of the controlled state switching determining section according to the first embodiment of the present invention.
  • FIG. 12 is a flowchart of a processing sequence of an operation limiting commanding section according to the first embodiment of the present invention.
  • FIG. 13 is a flowchart of a processing sequence of a solenoid valve actuating section according to the first embodiment of the present invention.
  • FIG. 14 is a flowchart of a processing sequence of an engine rotation control section according to the first embodiment of the present invention.
  • FIG. 15 is a flowchart of an additional processing sequence of a process of determining switching from a normal mode, as a subroutine of a controlled state switching determining section according to a second embodiment of the present invention.
  • FIG. 1 is a view illustrating an appearance of a hydraulic excavator as an example of a construction machine according to a first embodiment of the present invention.
  • the hydraulic excavator (construction machine) includes a crawler-type lower track structure 1 , an upper swing structure 2 swingably mounted on the lower track structure 1 , and a front implement 3 for performing excavating work or the like.
  • the lower track structure 1 includes a pair of left and right track hydraulic motors (not illustrated) and has crawlers independently rotatable to move forwardly and rearwardly by the track hydraulic motors and speed reducer mechanisms thereof, etc.
  • the upper swing structure 2 includes a cabin 4 housing therein operation devices for controlling the hydraulic excavator to operate in various ways, a prime mover such as an engine, a hydraulic pump and a swing motor (not illustrated), etc.
  • the swing motor swings the upper swing structure 2 leftwardly or rightwardly with respect to the lower track structure 1 .
  • the cabin 4 houses therein a display device 5 (illustrated in FIG. 2 ) for displaying various instruments and machine body information that allow an operator to check the situation of the hydraulic excavator (work machine).
  • the front implement 3 includes a boom 3 a , an arm 3 b , and a bucket 3 c .
  • the boom 3 a is vertically moved by a boom cylinder 3 d .
  • the arm 3 b is operated toward a dumping side (opening side) or a crowding side (gathering side) by an arm cylinder 3 e .
  • the bucket 3 c is operated toward the dumping side or the crowding side by a bucket cylinder 3 f.
  • 3D sensors 6 , 7 , 8 , and 9 as obstacle sensors for detecting a peripheral obstacle are mounted on the vehicle body of the hydraulic excavator respectively at rear, left, and right ends thereof.
  • Each of the 3D sensors includes an infrared sensor of the TOF (Time-Of-Flight) type, determines whether an object is detected or not in a predetermined detection range, determines in itself whether an obstacle is detected or not, and outputs the determined result by CAN communication.
  • TOF Time-Of-Flight
  • FIG. 2 is a view illustrating positions where the obstacle sensors (3D sensors 6 through 9 ) are installed and the detection areas thereof.
  • the 3D sensor 6 is mounted on a left side of the rear end of the vehicle body.
  • the 3D sensor 7 is mounted on a right side of the rear end of the vehicle body.
  • the 3D sensor 8 is mounted on the left end of the vehicle body.
  • the 3D sensor 9 is mounted on the right end of the vehicle body.
  • the 3D sensors are given respective spatial extents (angles) established therefor that are vertically and horizontally detectable. The detection ranges of these four 3D sensors cover a space behind the vehicle body in the periphery thereof.
  • the detection areas are established to detect an obstacle that is present in an area where the upper swing structure 2 moves in a short period of time when the hydraulic excavator is about to swing and travel.
  • the area detected by the 3D sensor 6 is defined as a detection area 10 , the area detected by the 3D sensor 7 as a detection area 11 , the area detected by the 3D sensor 8 as a detection area 12 , and the area detected by the 3D sensor 9 as a detection area 13 .
  • the detection areas 10 through 13 are established in a position higher than the lower track structure 1 such that the crawlers of the lower track structure 1 is not detected as an obstacle.
  • the 3D sensors 6 through 9 determine whether an obstacle is present in the respective detection areas 10 through 13 or not.
  • the time at which the 3D sensors 6 through 9 detect one or more obstacles (persons or objects) that are present in the detection areas 10 through 13 provided by the 3D sensors 6 through 9 as the obstacle sensors is regarded as an obstacle detection time.
  • FIG. 3 is a diagram illustrating a system configuration according to the present embodiment.
  • the cabin 4 of the hydraulic excavator houses therein a vehicle body controller 14 for controlling operation of the construction machine in whole, a lock switch 15 as a lever switch for operating an operation lock device that selectively locks and unlocks operation of the vehicle body in whole, the display device 5 for displaying various instruments and machine body information that allow the operator to check the situation of the hydraulic excavator, a switch box 16 for manually changing engine rotational speeds and operating the display device 5 , and a monitor controller 17 for accepting various switch input signals from the switch box 16 and changing displayed contents of the display device 5 .
  • a vehicle body controller 14 for controlling operation of the construction machine in whole
  • a lock switch 15 as a lever switch for operating an operation lock device that selectively locks and unlocks operation of the vehicle body in whole
  • the display device 5 for displaying various instruments and machine body information that allow the operator to check the situation of the hydraulic excavator
  • a switch box 16 for manually changing engine rotational speeds and operating the display device 5
  • a monitor controller 17 for accepting various switch input signals from the switch box 16
  • the cabin 4 of the hydraulic excavator also houses therein the operation devices for controlling the hydraulic excavator to operate in various ways.
  • the operation devices are illustrated as three representative operation levers including a swing operation lever 19 for indicating either left swing operation or right swing operation, a travel operation lever 20 for indicating either right forward travel operation, right rearward travel operation, left forward travel operation, or left rearward travel operation, and a front implement operation lever 21 for indicating either boom raising operation, boom lowering operation, arm crowding operation, arm dumping operation, bucket crowding operation, or bucket dumping operation.
  • the hydraulic excavator includes an engine 22 as the prime mover and an engine controller 23 electrically connected to the engine 22 .
  • the engine controller 23 identifies the state of the engine 22 from signals from a temperature sensor and a pickup sensor that are incorporated in the engine 22 , and controls valves and so on included in the engine 22 , to control the rotational speed and torque of the engine 22 .
  • the vehicle body controller 14 , the monitor controller 17 , and the engine controller 23 are electrically connected to each other by CAN communication, and send and receive necessary information.
  • the vehicle body controller 14 determines a target engine rotational speed depending on an engine control dial voltage, operation states of the operation levers 19 through 21 , a pump load state, and a temperature condition, and sends the determined target engine rotational speed to the engine controller 23 .
  • the engine controller 23 controls the engine 22 to achieve the target engine rotational speed, calculates an actual engine rotational speed from the signal from the pickup sensor incorporated in the engine 22 , and sends the calculated actual engine rotational speed to the vehicle body controller 14 .
  • the monitor controller 17 can acquire the target engine rotational speed and the actual engine rotational speed that are present in the CAN communication, the monitor controller 17 can control the display device 5 to display the target engine rotational speed and the actual target engine rotational speed as one of displayed states of the vehicle body.
  • the hydraulic excavator includes a plurality of hydraulic pumps for simultaneously operating a plurality of hydraulic actuators.
  • FIG. 3 one of those hydraulic pumps is illustrated as a representative hydraulic pump.
  • Each of the operation levers 19 through 21 includes a pilot valve as a manual pressure reducing valve, and reduces a primary pressure depending on the lever operation amount to generate a pilot valve secondary pressure.
  • the generated secondary pressures from the operation levers 19 through 21 move a plurality of spools (directional control valves) in the control valve 25 , adjusting the flow of the hydraulic operating fluid delivered from the hydraulic pump 24 to operate the corresponding hydraulic actuators.
  • a hydraulic fluid source 26 supplied from a pilot pump actuated by the engine 22 supplies a hydraulic operating fluid to a pump regulator 27 and a lock valve 28 as the operation lock device.
  • the hydraulic operating fluid supplied from the hydraulic fluid source 26 is kept under a pilot valve primary pressure of 4 MPa by an unillustrated pilot relief valve.
  • the pump regulator 27 includes a pump flow rate control solenoid valve as a solenoid proportional valve that reduces and uses the pilot valve primary pressure from the hydraulic fluid source 26 .
  • the pump flow rate control solenoid valve reduces the pilot valve primary pressure depending on an electric current (mA) outputted from the vehicle body controller 14 .
  • the pump regulator 27 incorporates a tilting (displacement volume) control mechanism for the pump 24 , and controls the volume (or delivery flow rate) of the pump 24 depending on an output pressure (secondary pressure) from the pump flow rate control solenoid valve.
  • the pump regulator 27 has such characteristics that it makes the pump volume minimum under a minimum pump flow rate control pressure (0 MPa) and it makes the pump volume maximum under a maximum pump flow rate control pressure (4 MPa).
  • the pump flow rate control solenoid valve is in an interruption position (0 MPa) when in an uncontrolled state (0 mA), and has such characteristics that the pump flow rate control pressure increases as the vehicle body controller 14 increases a command electric current.
  • the pump regulator 27 is combined with a pump flow rate control pressure sensor 33 that is used for detecting the pump flow rate control pressure.
  • a signal from the pump flow rate control pressure sensor 33 is inputted to the vehicle body controller 14 , which estimates a pump displacement from the characteristics of pump displacements with respect to pump flow rate control pressures and multiplies the estimated pump displacement by the engine rotational speed, thereby calculating a delivery flow rate of the hydraulic operating fluid delivered from the hydraulic pump 24 .
  • the lock valve 28 is the operation lock device that selectively locks and unlocks operation of the vehicle body in whole.
  • the lock valve 28 is switched between an interruption position and a fluid communication position by a solenoid actuated by the vehicle body controller 14 .
  • the lock switch 15 When a lock lever (not illustrated) disposed in the cabin 4 is in a locked position, the lock switch 15 is OFF (its terminals are open or disconnected). The vehicle body controller 14 monitors the state of the lock switch 15 , and de-energizes the lock valve 28 (holds the lock valve 28 in the interruption position) when the lock switch 15 is OFF.
  • lock switch 15 When the lock lever disposed in the cabin 4 is in an unlocked position, lock switch 15 is ON (its terminals are connected).
  • the vehicle body controller 14 monitors the state of the lock switch 15 , and energizes the lock valve 28 (holds the lock valve 28 in the fluid communication position) by applying 24 V to the lock valve 28 when the lock switch 15 is ON.
  • the swing operation lever 19 , the travel operation lever 20 , and the front implement operation lever 21 are supplied with the pilot valve primary pressure.
  • the pilot valve secondary pressure increases and is able to shift the spools in the control valve 25 , so that the vehicle body becomes operational.
  • a swing operation pressure sensor 29 for detecting the pilot valve secondary pressure is included in a pilot circuit between the swing operation lever 19 and the control valve 25 .
  • a travel operation pressure sensor 30 for detecting the pilot valve secondary pressure is included in a pilot circuit between the travel operation lever 20 and the control valve 25 .
  • a front implement operation pressure sensor 31 for detecting the pilot valve secondary pressure is included in a pilot circuit between the front implement operation lever 21 and the control valve 25 .
  • Signals from the swing operation pressure sensor 29 , the travel operation pressure sensor 30 , and the front implement operation pressure sensor 31 are inputted to the vehicle body controller 14 , which identifies the situation in which the hydraulic excavator is operated.
  • the vehicle body controller 14 determines whether the vehicle body is operated or not on the basis of the signals inputted from the operation pressure sensors 29 through 31 .
  • a pump delivery pressure sensor 32 for detecting a pump delivery pressure is included in a delivery circuit between the hydraulic pump 24 and the control valve 25 .
  • a signal from the pump delivery pressure sensor 32 is inputted to the vehicle body controller 14 , which identifies a pump load of the hydraulic excavator.
  • the vehicle body controller 14 calculates an operation-based target pump flow rate depending on the engine rotational speed and the input signals from the operation pressure sensors 29 through 31 . Further, the vehicle body controller 14 calculates a limited horsepower (kW) depending on the engine rotational speed, the operation situation, and other vehicle body states (temperature, etc.), and calculates an upper limit pump flow rate due to the limiting of the horsepower from the input signal from the pump delivery pressure sensor 32 and the limited horsepower. The vehicle body controller 14 selects a smaller one of the operation-based target pump flow rate and the upper limit pump flow rate due to the limiting of the horsepower, as a target pump flow rate, and actuates the pump flow rate control solenoid valve so as to achieve the target pump flow rate.
  • kW horsepower
  • the vehicle body controller 14 selects a smaller one of the operation-based target pump flow rate and the upper limit pump flow rate due to the limiting of the horsepower, as a target pump flow rate, and actuates the pump flow rate control solenoid valve so as to achieve the target pump flow rate.
  • the cabin 4 of the hydraulic excavator houses therein a periphery detection monitor 18 for indicating to the operator information detected by the 3D sensors 6 through 9 and a state of vehicle body operation limitation based on peripheral detection.
  • the 3D sensors 6 through 9 , the periphery detection monitor 18 , and the vehicle body controller 14 are connected to each other by CAN communication, and send and receive necessary information.
  • the CAN communication makes it possible for the vehicle body controller 14 and the periphery detection monitor 18 to learn whether an obstacle has been detected in each of the detection areas 10 through 13 . Further, in a case where an obstacle (a person or an object) is present in one or more of the detection areas 10 through 13 created by the 3D sensors 6 through 9 as the obstacle sensors, the vehicle body controller 14 determines obstacle detection. In a case where an obstacle (a person or an object) is not present in any of the detection areas 10 through 13 , the vehicle body controller 14 determines obstacle non-detection.
  • a swing pilot pressure interruption solenoid valve 34 is included as a vehicle body operation limiting device in the pilot circuit between the swing operation lever 19 and the control valve 25 .
  • the swing pilot pressure interruption solenoid valve 34 is in a circuit fluid communication state when not controlled (0 mA). As an electric current (mA) outputted from the vehicle body controller 14 to the swing pilot pressure interruption solenoid valve 34 increases, the swing pilot pressure interruption solenoid valve 34 is brought into a circuit interruption state, making the upper swing structure 2 impossible to swing.
  • a travel pilot pressure interruption solenoid valve 35 is included as a vehicle body operation limiting device in the pilot circuit between the travel operation lever 20 and the control valve 25 .
  • the travel pilot pressure interruption solenoid valve 35 is in a circuit fluid communication state when not controlled (0 mA). As an electric current (mA) outputted from the vehicle body controller 14 to the travel pilot pressure interruption solenoid valve 35 increases, the travel pilot pressure interruption solenoid valve 35 is brought into a circuit interruption state, making the lower track structure 1 impossible to travel.
  • the cabin 4 houses therein a control canceling switch 36 including a momentary pushbutton switch as a control canceling device.
  • control canceling switch 36 When the control canceling switch 36 is not pressed, the control canceling switch 36 is OFF (its terminals are open or disconnected). When the control canceling switch 36 is pressed, the control canceling switch 36 is ON (its terminals are connected). The vehicle body controller 14 monitors an ON/OFF state of the control canceling switch 36 to recognize whether the control canceling switch 36 is pressed or not.
  • the control canceling switch 36 may be provided as one of grip switches on the operation levers 19 through 21 or may be provided as an individual switch positioned in a location different from that of the operation levers 19 through 21 .
  • control canceling switch 36 is provided as an individual switch, then the operator is required to take his/her hands off the operation levers to press the control canceling switch 36 . In a case where the operator is to press the control canceling switch 36 while the vehicle body is in operation, the operator is required to temporarily interrupt work.
  • the individual switch is more effective in that it prompts the operator to check the periphery before pressing the control canceling switch 36 .
  • FIG. 4 is a diagram illustrating the makeup of the controller 14 for limiting operation of the vehicle body upon detection of an obstacle.
  • the vehicle body controller 14 has an operation limiting control section 37 as a control section for limiting operation of the vehicle body upon detection of an obstacle.
  • the operation limiting control section 37 includes a controlled state switching determining section 38 as a control section for determining whether a control mode state of the vehicle body is a normal state, a temporary cancelation state, or a permanent cancelation state.
  • the operation limiting control section 37 also includes an operation limiting command section 39 as a control section for commanding the operation limiting device to work.
  • the vehicle body controller 14 has, other than the operation limiting control section 37 , a detection determining section 40 for determining whether there is an obstacle in the periphery of the vehicle body or not from detected states of the detection areas 10 through 13 , an operation state determining section 41 for determining whether the vehicle body is in an operation/non-operation state from the magnitudes of operation pressures converted into pressure values (MPa) depending on input voltages from the operation pressure sensors 29 through 31 in the vehicle body controller 14 , a solenoid valve actuating section 42 for calculating an electric current value for actuating the swing pilot pressure interruption solenoid valve 34 or the travel pilot pressure interruption solenoid valve 35 in response to a swing stop command or a travel stop command from the operation limiting command section 39 , and an engine rotation control section 43 for limiting a target engine rotational speed to be given to the engine controller 23 in response to a rotational speed command from the operation limiting command section 39 .
  • a detection determining section 40 for determining whether there is an obstacle in the periphery of the
  • Processing sequences of these control sections are executed at all times in each of control periods of the vehicle body controller 14 after the engine has started and a periphery detection system has started (while the periphery detection system is in operation).
  • FIG. 5 is a flowchart of a processing sequence of the detection determining section 40 .
  • the detection determining section 40 determines whether the 3D sensor 6 has detected an item (a person or an object) in the detection area 10 or not (step S 1 ). If the 3D sensor 6 has detected an item in the detection area 10 , then the detection determining section 40 determines that the vehicle body is in a detection state, and sets an obstacle detection state v 1 that is a variable to “detection” (step S 6 ).
  • the detection determining section 40 determines whether the 3D sensor 7 has detected an item in the detection area 11 or not (step S 2 ). If the 3D sensor 7 has detected an item in the detection area 11 , then the detection determining section 40 determines that the vehicle body is in a detection state, and sets the obstacle detection state v 1 that is a variable to “detection” (step S 6 ).
  • the detection determining section 40 determines whether the 3D sensor 8 has detected an item in the detection area 12 or not (step S 3 ). If the 3D sensor 8 has detected an item in the detection area 12 , then the detection determining section 40 determines that the vehicle body is in a detection state, and sets the obstacle detection state v 1 that is a variable to “detection” (step S 6 ).
  • the detection determining section 40 determines whether the 3D sensor 9 has detected an item in the detection area 13 or not (step S 4 ). If the 3D sensor 9 has detected an item in the detection area 13 , then the detection determining section 40 determines that the vehicle body is in a detection state, and sets the obstacle detection state v 1 that is a variable to “detection” (step S 6 ).
  • the detection determining section 40 determines that the vehicle body is in a non-detection state, and sets the obstacle detection state v 1 that is a variable to “non-detection” (step S 5 ).
  • FIG. 6 is a flowchart of a portion for determining an operation state with respect to each event of operation, of a processing sequence of the operation state determining section 41 .
  • the operation state determining section 41 determines whether or not a swing operation pressure is equal to or higher than an operation ON threshold value C 1 (e.g., 0.5 MPa) (step S 33 ). If the swing operation pressure is equal to or higher than the operation ON threshold value C 1 , then the operation state determining section 41 determines that a swing operation is performed, and sets a swing operation state v 10 that is a variable to “during operation” (step S 34 ). If the swing operation pressure is lower than the operation ON threshold value C 1 , then the operation state determining section 41 determines that a swing operation is not performed, and sets the swing operation state v 10 that is a variable to “non-operation” (step S 35 ).
  • an operation ON threshold value C 1 e.g., 0.5 MPa
  • the operation state determining section 41 determines whether or not a travel operation pressure is equal to or higher than the operation ON threshold value C 1 (e.g., 0.5 MPa) (step S 36 ). If the travel operation pressure is equal to or higher than the operation ON threshold value C 1 , then the operation state determining section 41 determines that a travel operation is performed, and sets a travel operation state v 11 that is a variable to “during operation” (step S 37 ). If the travel operation pressure is lower than the operation ON threshold value C 1 , then the operation state determining section 41 determines that the travel operation is not performed, and sets the travel operation state v 11 that is a variable to “non-operation” (step S 38 ).
  • the operation ON threshold value C 1 e.g., 0.5 MPa
  • the operation state determining section 41 determines whether or not a front implement operation pressure is equal to or higher than the operation ON threshold value C 1 (e.g., 0.5 MPa) (step S 39 ). If the front implement operation pressure is equal to or higher than the operation ON threshold value C 1 , then the operation state determining section 41 determines that the front implement is operated, and sets a front implement operation state v 12 that is a variable to “during operation” (step S 40 ). If the front implement operation pressure is lower than the operation ON threshold value C 1 , then the operation state determining section 41 determines that the front implement is not operated, and sets the front implement operation state v 12 that is a variable to “non-operation” (step S 41 ).
  • the operation ON threshold value C 1 e.g., 0.5 MPa
  • FIG. 7 is a flowchart of a portion for determining an operation state with respect to the vehicle body, of the processing sequence of the operation state determining section 41 .
  • the operation state determining section 41 determines whether the swing operation state v 10 represents “during operation” or not (step S 7 ). If the swing operation state v 10 represents “during operation,” then the operation state determining section 41 determines that the vehicle body is in an operation state, and sets a vehicle body operation state v 2 that is a variable to “during operation” (step S 11 ).
  • the operation state determining section 41 determines whether the travel operation state v 11 represents “during operation” or not (step S 8 ). If the travel operation state v 11 represents “during operation,” then the operation state determining section 41 determines that the vehicle body is in an operation state, and sets the vehicle body operation state v 2 that is a variable to “during operation” (step S 11 ).
  • the operation state determining section 41 determines whether the front implement operation state v 12 represents “during operation” or not (step S 9 ). If the front implement operation state v 12 represents “during operation,” then the operation state determining section 41 determines that the vehicle body is in an operation state, and sets the vehicle body operation state v 2 that is a variable to “during operation” (step S 11 ).
  • the operation state determining section 41 determines that the vehicle body is in a non-operation state, and sets the vehicle body operation state v 2 that is a variable to “non-operation” (step S 10 ).
  • FIG. 8 is a flowchart of an entire processing sequence of the controlled state switching determining section 38 .
  • the controlled state switching determining section 38 selects a processing sequence to be carried out depending on whether a control mode state v 3 at present (in a preceding step of the control sequence) represents “normal,” “temporary cancelation,” or “permanent cancelation” (step S 12 ).
  • control mode state v 3 at present represents “normal,” then the controlled state switching determining section 38 carries out a process of determining switching from a normal mode (step S 13 ). If the control mode state v 3 at present represents “temporary cancelation,” then the controlled state switching determining section 38 carries out a process of determining switching from a temporary cancelation mode (step S 14 ). If the control mode state v 3 at present represents “permanent cancelation,” then the controlled state switching determining section 38 carries out a process of determining switching from a permanent cancelation mode (step S 15 ).
  • the control mode state v 3 has a default value representing “normal.” When the engine is started next time after the key has once been turned off, the processing sequence always begins with the control mode state v 3 representing “normal.”
  • FIG. 9 is a flowchart of a processing sequence of the process of determining switching from the normal mode (step S 13 ), as a subroutine of the controlled state switching determining section 38 .
  • the vehicle body controller 14 determines whether the control canceling switch 36 is pressed or not by checking whether the terminals of the control canceling switch 36 are disconnected or connected. According to the present embodiment, if the control canceling switch 36 is pressed, then the vehicle body controller 14 determines that a control canceling switch state is “ON,” and if the control canceling switch 36 is not pressed, then the vehicle body controller 14 determines that the control canceling switch state is “OFF.”
  • step S 13 the controlled state switching determining section 38 determines whether the control canceling switch state has changed from OFF to ON (whether the control canceling switch 36 has changed from a non-pressed state to a pressed state or not) (step S 16 ).
  • step S 16 determines that the answer to step S 16 is NO, then, since the control canceling switch 36 is not pressed, the controlled state switching determining section 38 puts an end to the processing sequence without switching the control mode state v 3 from “normal.”
  • control canceling switch 36 If the control canceling switch 36 is pressed and the control canceling switch state has changed from OFF to ON, the controlled state switching determining section 38 starts counting a control canceling switch ON time t 1 (step S 17 ).
  • the controlled state switching determining section 38 determines whether the control canceling switch state is ON or not (whether the control canceling switch 36 is pressed or not) (step S 18 ). If the control canceling switch state is ON, then the controlled state switching determining section 38 determines whether or not the control canceling switch ON time t 1 is equal to or longer than a cancelation mode determining time T 1 (e.g., 2 seconds) (step S 19 ). If the control canceling switch ON time t 1 is shorter than the cancelation mode determining time T 1 , then the processing sequence goes back to step S 18 and is repeated.
  • a cancelation mode determining time T 1 e.g. 2 seconds
  • step S 18 If the controlled state switching determining section 38 determines that the control canceling switch state is not ON in step S 18 , i.e., if the pushbutton of the control canceling switch 36 is pressed for such a short period of time that the control canceling switch 36 is no longer pressed by the time the control canceling switch ON time t 1 reaches the cancelation mode determining time T 1 , then the controlled state switching determining section 38 switches the control mode state v 3 to “temporary cancelation” (step S 20 ).
  • control canceling switch ON time t 1 becomes equal to or longer than the cancelation mode determining time T 1 with the control canceling switch state being ON, i.e., if the pushbutton of the control canceling switch 36 is pressed for such a long period of time that the control canceling switch 36 is continuously pressed until the control canceling switch ON time t 1 reaches the cancelation mode determining time T 1 , then the controlled state switching determining section 38 switches the control mode state v 3 to “permanent cancelation” (step S 21 ).
  • step S 22 After having switched the control mode state v 3 from “normal” in step S 20 or step S 21 , the controlled state switching determining section 38 stops counting the control canceling switch ON time t 1 and resets the control canceling switch ON time t 1 to a default value (0) (step S 22 ).
  • FIG. 10 is a flowchart of a processing sequence of the process of determining switching from the temporary cancelation mode (step S 14 ), as a subroutine of the controlled state switching determining section 38 .
  • the vehicle body controller 14 determines whether the lock switch 15 is pressed or not by checking whether the terminals of the lock switch 15 are disconnected or connected.
  • a lock switch state is “OFF.”
  • the vehicle body controller 14 de-energizes the lock valve 28 into the interruption position, disabling the vehicle body operationally in whole.
  • the lock switch state is “ON.”
  • the vehicle body controller 14 applies 24 V to the lock valve 28 to energize the lock valve 28 into the fluid communication position, enabling the vehicle body to be operational.
  • step S 14 the controlled state switching determining section 38 starts counting a non-detection time t 2 (step S 23 ).
  • the controlled state switching determining section 38 determines whether the control canceling switch state has changed from OFF to ON or not (whether the switch has changed from a non-pressed state to a pressed state or not) (step S 24 ).
  • step S 24 If the controlled state switching determining section 38 determines that the answer to step S 24 is YES, then the controlled state switching determining section 38 switches the control mode state v 3 to “normal” (step S 25 ). Thereafter, the controlled state switching determining section 38 stops counting the non-detection time t 2 and resets the non-detection time t 2 to a default value (0) (step S 26 ), after which the processing sequence is ended.
  • control canceling switch 36 If the control canceling switch 36 is not pressed and the control canceling switch state remains to be OFF, then the controlled state switching determining section 38 determines whether the lock switch state has changed from ON to OFF or not (whether the lock lever has shifted from the unlocked position to the locked position or not) (step S 27 ).
  • step S 27 If the controlled state switching determining section 38 determines that the answer to step S 27 is YES, then the controlled state switching determining section 38 switches the control mode state v 3 to “normal” (step S 25 ). Thereafter, the controlled state switching determining section 38 stops counting the non-detection time t 2 and resets the non-detection time t 2 to the default value (0) (step S 26 ), after which the processing sequence is ended.
  • the controlled state switching determining section 38 determines whether the obstacle detection state v 1 represents “non-detection” or not (step S 28 ). If the obstacle detection state v 1 does not represent “non-detection,” i.e., if the obstacle detection state v 1 represents “detection” where the 3D sensors 6 through 9 have detected one or more obstacles, then the controlled state switching determining section 38 does not switch the control mode state v 3 from “temporary cancelation,” and resets the non-detection time t 2 to the default value (0) (step S 29 ). The processing sequence goes back to step S 24 , and the determining process is continued.
  • step S 28 If the obstacle detection state v 1 represents “non-detection” in step S 28 , then the controlled state switching determining section 38 determines whether or not the non-detection time t 2 is equal to or longer than a control mode return time T 2 (e.g., 30 seconds) (step S 30 ). If the non-detection time t 2 is shorter than the control mode return time T 2 , then the processing sequence goes back to step S 24 , and the determining process is continued.
  • a control mode return time T 2 e.g. 30 seconds
  • the controlled state switching determining section 38 switches the control mode state v 3 to “normal” (step S 25 ). Thereafter, the controlled state switching determining section 38 stops counting the non-detection time t 2 and resets the non-detection time t 2 to the default value (0) (step S 26 ), after which the processing sequence is ended.
  • FIG. 11 is a flowchart of a processing sequence of a process of determining switching from the permanent cancelation mode (step S 15 ), as a subroutine of the controlled state switching determining section 38 .
  • step S 15 the controlled state switching determining section 38 determines whether the control canceling switch state has changed from OFF to ON or not (whether the control canceling switch 36 has changed from the non-pressed state to the pressed state or not) (step S 31 ).
  • step S 32 the controlled state switching determining section 38 switches the control mode state v 3 to “normal” (step S 32 ), after which the processing sequence is ended. If the control canceling switch 36 is not pressed and the control canceling switch state remains to be OFF, then the controlled state switching determining section 38 does not switch the control mode state v 3 from “permanent cancelation,” after which the processing sequence is ended.
  • FIG. 12 is a flowchart of a processing sequence of the operation limiting command section 39 .
  • the operation limiting command section 39 determines whether the control mode state v 3 represents “normal” or not (step S 42 ). If the control mode state v 3 represents “normal” (if the control mode state v 3 does not represent “temporary cancelation” or “permanent cancelation”), then the operation limiting command section 39 determines whether the obstacle detection state v 1 represents “detection” or not (step S 43 ). If there is an item (a person or an object) in the periphery of the vehicle body and the obstacle detection state v 1 represents “detection,” then the operation limiting command section 39 sets a rotational speed command v 6 to “limited rotational speed” (e.g., 800 rpm) (step S 44 ).
  • limited rotational speed e.g. 800 rpm
  • the engine rotational speed of the vehicle body is limited to a low value through the processing of the engine rotation control section 43 to be described later.
  • a high engine rotational speed e.g. 1800 rpm
  • the operator can notice the detection through a bodily sensation in addition to a warning or display, so that higher safety can be achieved.
  • the operation limiting command section 39 determines whether the swing operation state v 10 represents “non-operation” or not (step S 45 ). If the swing operation state v 10 represents “non-operation” where no swing operation is performed while an obstacle is being detected, the operation limiting command section 39 sets a swing stop command v 4 to “interruption pressure” (e.g., 0 MPa) (step S 46 ).
  • the operation limiting command section 39 determines whether the travel operation state v 11 represents “non-operation” or not (step S 47 ). If the travel operation state v 11 represents “non-operation” where no travel operation is performed while an obstacle is being detected, the operation limiting command section 39 sets a travel stop command v 5 to “interruption pressure” (e.g., 0 MPa) (step S 48 ).
  • vehicle body operation limitation for limiting vehicle body operation is enabled.
  • the operation limiting command section 39 determines whether the lock switch state is OFF or not (step S 49 ).
  • the operation limiting command section 39 sets the rotational speed command v 6 to “maximum rotational speed” (e.g., 2000 rpm) (step S 50 ), sets the swing stop command v 4 to “open pressure” (e.g., 4 MPa) (step S 51 ), and sets the travel stop command v 5 to “open pressure” (e.g., 4 MPa) (step S 52 ).
  • the vehicle body operation limitation remains enabled even if the obstacle detection state v 1 no longer represents “detection.”
  • the vehicle body Since the lock valve 28 is in the interruption position while the lock lever is in the locked position, the vehicle body is operationally disabled in whole. By permitting the vehicle body operation limitation to be canceled only in this state, it is possible to avoid a situation where swinging/traveling operation is canceled and the vehicle body is allowed to move abruptly when no obstacle is detected while the operator has unintentionally moved down the operation levers 19 and 20 , for example, resulting in higher safety.
  • FIG. 13 is a flowchart of a processing sequence of the solenoid valve actuating section 42 .
  • the solenoid valve actuating section 42 is a control section for actually actuating the swing pilot pressure interruption solenoid valve 34 and the travel pilot pressure interruption solenoid valve 35 as the vehicle body operation limiting devices according to solenoid valve pressures represented by the swing stop command v 4 and the travel stop command v 5 as calculated results from the operation limiting command section 39 .
  • the solenoid valve actuating section 42 determines whether the swing stop command v 4 represents “interruption pressure” or not (step S 53 ). If the swing stop command v 4 represents “interruption pressure,” then the solenoid valve actuating section 42 sets a swing pilot pressure interruption solenoid valve current v 7 to “interruption current” (e.g., 600 mA) (step S 54 ). If the swing stop command v 4 does not represent “interruption pressure” (if the swing stop command v 4 represents “open pressure”), then the solenoid valve actuating section 42 sets the swing pilot pressure interruption solenoid valve current v 7 to “open current” (e.g., 0 mA) (step S 55 ).
  • the solenoid valve actuating section 42 determines whether the travel stop command v 5 represents “interruption pressure” or not (step S 56 ). If the travel stop command v 5 represents “interruption pressure,” then the solenoid valve actuating section 42 sets a travel pilot pressure interruption solenoid valve current v 8 to “interruption current” (e.g., 600 mA) (step S 57 ). If the travel stop command v 5 does not represent “interruption pressure” (if the travel stop command v 5 represents “open pressure”), then the solenoid valve actuating section 42 sets the travel pilot pressure interruption solenoid valve current v 8 to “open current” (e.g., 0 mA) (step S 58 ).
  • the vehicle body controller 14 incorporates therein a solenoid valve driver as an analog output circuit for actuating the solenoid of a proportional solenoid valve.
  • the vehicle body controller 14 supplies an electric current to the analog output circuit to generate the swing pilot pressure interruption solenoid valve current v 7 and the travel pilot pressure interruption solenoid valve current v 8 , thereby actuating the swing pilot pressure interruption solenoid valve 34 and the travel pilot pressure interruption solenoid valve 35 (step S 59 ).
  • FIG. 14 is a flowchart of a processing sequence of the engine rotation control section 43 .
  • the engine rotation control section 43 selects, under predetermined conditions, a required rotational speed depending on the engine control dial voltage operated by the operator, a required rotational speed depending on the operation amount of the operation levers, or a required rotational speed depending on the operation environments including the radiator coolant temperature, the hydraulic operating fluid temperature, etc., and eventually sends the selected required rotational speed as a target engine rotational speed v 9 through the CAN communication to the engine controller 23 , thereby achieving an actual engine rotational speed required of the vehicle body.
  • a required rotational speed according to a processing sequence common with a conventional hydraulic excavator, other than the rotational speed command v 6 sent from the operation limiting command section 39 is calculated as a reference required rotational speed v 13 by a processing sequence not illustrated in FIG. 14 (step S 60 ).
  • the rotational speed command v 6 and the reference required rotational speed v 13 are compared with each other at a final stage of the processing sequence of the engine rotation control section 43 .
  • step S 60 the engine rotation control section 43 determines whether the rotational speed command v 6 sent from the operation limiting command section 39 is larger than the reference required rotational speed v 13 (step S 61 ).
  • the engine rotation control section 43 sets the target engine rotational speed v 9 to “reference required rotational speed v 13 ,” thereby making the hydraulic excavator usable as an ordinary hydraulic excavator (step S 62 ).
  • the engine rotation control section 43 sets the target engine rotational speed v 9 to “rotational speed command v 6 ,” thereby forcefully limiting the engine rotational speed to limit operation of the vehicle body (step S 63 ).
  • a hydraulic excavator includes actuators 3 d through 3 h , operation devices (operation levers 19 through 21 ) for instructing the actuators 3 d through 3 h to operate, obstacle sensors (3D sensors 6 through 9 ) for detecting an obstacle in the periphery, a controller 14 for performing operation limiting control to limit operation of the actuators 3 d through 3 h in a case where the obstacle sensors (3D sensors 6 through 9 ) detect an obstacle, and a control canceling device (control canceling switch 36 ) for instructing the controller 14 to cancel the operation limiting control, in which the controller 14 is configured to have a normal mode as a control mode for making the operation limiting control effective and a temporary cancelation mode as a control mode for temporarily canceling the operation limiting control, switch to the temporary cancelation mode in response to operation of the control canceling device (control canceling switch 36 ) while in the normal mode, and switch back to the normal mode in a case where a predetermined condition not responsive to operation of the control canceling device (control
  • the operator when the vehicle body is about to start moving at work, after the operator has checked safety in the periphery, the operator operates the control canceling switch 36 to switch from the normal mode in which operation limitation is enabled to the temporary cancelation mode in which operation limitation is not enabled.
  • the hydraulic excavator even if an object required for work is present in the periphery of the vehicle body, it is possible for the hydraulic excavator to perform work as an ordinary hydraulic excavator.
  • the controller 14 when the predetermined condition not responsive to operation of the control canceling switch 36 is satisfied in the temporary cancelation mode, the controller 14 returns to the normal mode independently of operation of the control canceling switch 36 , making it possible to reduce the possibility of an accident due to contact between the construction machine and a worker in the periphery thereof.
  • the hydraulic excavator according to the present embodiment further includes an operation lock device (lock valve 28 ) switchable between a locked position (interruption position) for inhibiting operation of the actuators 3 d through 3 h and an unlocked position (fluid communication position) for permitting operation of the actuators 3 d through 3 h , in which the predetermined condition includes switching of the operation lock device (lock valve 28 ) from the unlocked position (fluid communication position) to the locked position (interruption position).
  • an operation lock device lock valve 28
  • the predetermined condition includes switching of the operation lock device (lock valve 28 ) from the unlocked position (fluid communication position) to the locked position (interruption position).
  • the controller 14 inasmuch as the controller 14 returns from the temporary cancelation mode to the normal mode in a stage where work is interrupted and the lock lever is locked (the lock switch 15 is OFF), when the vehicle body is about to move next, a vehicle body operation limiting device works again due to obstacle detection, thereby increasing safety.
  • the controller 14 can return to the normal mode even if the operator forgets to take an operation action to return from the temporary cancelation mode, resulting in increased safety to lower the possibility of an accident due to contact between the construction machine that is about to move and a worker in the periphery.
  • the predetermined condition includes the continuation of a state in which the obstacle sensors (3D sensors 6 through 9 ) do not detect an obstacle over a predetermined period of time (control mode return time T 2 ).
  • the controller 14 since the controller 14 returns from the temporary cancelation mode to the normal mode when the control mode return time T 2 (e.g., 30 seconds) has elapsed while the obstacle detection state v 1 is representing “non-detection” even if the lock valve 28 (operation lock device) is not operated, the controller 14 can return to the normal mode even if the operator forgets to take an operation action to return from the temporary cancelation mode, resulting in increased safety to lower the possibility of an accident due to contact between the construction machine that is about to move and a worker in the periphery.
  • T 2 e.g. 30 seconds
  • the control mode return time T 2 is established taking into account operability and safety sufficiently in advance. For increased safety, the controller 14 should return from the temporary cancelation state to the normal state in as short a period of time as possible, which however may possibly reduce operability.
  • control mode return time T 2 is established taking into account operability and safety sufficiently in advance.
  • the controller 14 further has a permanent cancelation mode that is a control mode for permanently canceling operation limiting control.
  • the controller 14 determines in the normal mode whether the controller 14 is to shift to the temporary cancelation mode or the permanent cancelation mode depending on how the control canceling device (control canceling switch 36 ) is operated, and the controller 14 shifts, in the permanent cancelation mode, to the normal mode in response to operation of the control canceling device (control canceling switch 36 ).
  • the control canceling device includes a momentary pushbutton switch.
  • the controller 14 shifts to the temporary cancelation mode in a case where a continuously pressed time (control canceling switch ON time t 1 ) of the control canceling switch 36 is shorter than a predetermined period of time (cancelation mode determining time T 1 ) in the normal mode, and shifts to the permanent cancelation mode in a case where the continuously pressed time (control canceling switch ON time t 1 ) of the control canceling switch 36 is equal to or longer than the predetermined period of time (cancelation mode determining time T 1 ) in the normal mode.
  • controller select shifting to the temporary cancelation mode or shifting to the permanent cancelation mode through operation of the single control canceling switch 36 .
  • a second embodiment of the present invention will be described below with reference to FIG. 15 .
  • the present embodiment allows the controller 14 to shift from the normal mode to the temporary cancelation mode independently of operation of the control canceling switch 36 . Differences from the first embodiment will mainly be described below.
  • FIG. 15 is a flowchart of an additional processing sequence of a process of determining switching from a normal mode (step S 13 ), as a subroutine of a controlled state switching determining section 38 according to the present embodiment.
  • the controlled state switching determining section 38 according to the present embodiment carries out the processing sequence illustrated in FIG. 15 concurrent with the processing sequence illustrated in FIG. 9 , as the process of determining switching from the normal mode (step S 13 ).
  • the controlled state switching determining section 38 starts counting a during-detection operation time t 3 (step S 64 ).
  • the controlled state switching determining section 38 determines whether the obstacle detection state v 1 represents “detection” or not (step S 65 ). If the obstacle detection state v 1 does not represent “detection” (if the obstacle detection state v 1 represents “non-detection”), then the controlled state switching determining section 38 stops counting the during-detection operation time t 3 , and resets the during-detection operation time t 3 to a default value (0) (step S 69 ), after which the processing sequence is ended.
  • the controlled state switching determining section 38 determines whether the vehicle body operation state v 2 represents “during operation” or not (step S 66 ). If the vehicle body operation state v 2 does not represent “during operation” (if the vehicle body operation state v 2 represents “non-operation”), then the controlled state switching determining section 38 stops counting the during-detection operation time t 3 , and resets the during-detection operation time t 3 to a default value (0) (step S 69 ), after which the processing sequence is ended.
  • the controlled state switching determining section 38 determines whether or not the during-detection operation time t 3 is equal to or longer than an automatic temporary cancelation shifting time T 3 (e.g., 5 seconds) (step S 67 ).
  • the controlled state switching determining section 38 sets the control mode state v 3 to “temporary cancelation” (step S 68 ), stops counting the during-detection operation time t 3 , and resets the during-detection operation time t 3 to a default value (0) (step S 69 ), after which the processing sequence is ended.
  • step S 65 If the during-detection operation time t 3 is shorter than the automatic temporary cancelation shifting time T 3 , then the processing sequence goes back to step S 65 and repeats the process of determining the obstacle detection state v 1 and the process of determining the vehicle body operation state v 2 .
  • the additional processing sequence of the process of determining switching from the normal mode makes it possible for the controller 14 to shift automatically to the temporary cancelation mode with the operator continuously operating the vehicle body without pressing the control canceling switch 36 while vehicle body operation limitation is being enabled with an obstacle detected during work in the normal mode.
  • the hydraulic excavator further includes operation sensors (operation pressure sensors 29 through 31 ) for detecting whether the operation devices (operation levers 19 through 21 ) are operated or not, in which the controller 14 shifts to the temporary cancelation mode if the operation sensors (operation pressure sensors 29 through 31 ) have detected operation of the operation devices (operation levers 19 through 21 ) continuously over a predetermined period of time (automatic temporary cancelation shifting time T 3 ) or longer while the obstacle sensors (3D sensors 6 through 9 ) are detecting an obstacle, other than in response to operation of the control canceling device (control canceling switch 36 ), in the normal mode.
  • operation sensors operation pressure sensors 29 through 31
  • T 3D sensors 6 through 9 for detecting whether the operation devices (operation levers 19 through 21 ) are operated or not
  • vehicle body operation limitation is enabled, limiting the engine rotational speed to make operation of the vehicle body slower, and the swing pilot pressure interruption solenoid valve 34 and the travel pilot pressure interruption solenoid valve 35 are switched to the interruption position, making the vehicle body impossible to swing and travel.
  • vehicle body operation limitation it is necessary to cancel vehicle body operation limitation in order to move away from the obstacle and to continue work in the presence of the obstacle in the periphery after having checked safety in the periphery.
  • control canceling switch 36 can cancel vehicle body operation limitation as a way of meeting such a need.
  • control canceling switch 36 for canceling vehicle body operation limitation is located in a position different from that of the operation levers 19 through 21 , the operator is required to take his/her hands off the operation levers 19 through 21 and then press the control canceling switch 36 .
  • the controller 14 shifts to the temporary cancelation mode to cancel vehicle body operation limitation when the operator has continuously operated the operation levers 19 through 21 for a certain period of time, it is possible to move the vehicle body to a place where it can be stopped in safety and change the posture of the vehicle body, without stopping the vehicle body.

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WO2024111434A1 (ja) * 2022-11-24 2024-05-30 住友建機株式会社 ショベルの制御装置
JP2024141723A (ja) * 2023-03-29 2024-10-10 コベルコ建機株式会社 旋回式作業機械の制御装置

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CN114207222B (zh) 2023-09-01
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