U.S. patent application number 17/623637 was filed with the patent office on 2022-08-25 for construction machine.
The applicant listed for this patent is HITACHI CONSTRUCTION MACHINERY CO., LTD.. Invention is credited to Ryota KAMEOKA, Akihiro NARAZAKI, Shinji NISHIKAWA, Koji SHIWAKU, Shinjiro YAMAMOTO.
Application Number | 20220267998 17/623637 |
Document ID | / |
Family ID | |
Filed Date | 2022-08-25 |
United States Patent
Application |
20220267998 |
Kind Code |
A1 |
NISHIKAWA; Shinji ; et
al. |
August 25, 2022 |
CONSTRUCTION MACHINE
Abstract
There is provided 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 a vehicle body while securing operability in
situations where an object required for work is present in the
periphery. A controller has 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. The controller shifts to the temporary
cancelation mode in response to operation of the control canceling
device while in the normal mode. The controller shifts 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.
Inventors: |
NISHIKAWA; Shinji;
(Kasumigaura-shi, JP) ; SHIWAKU; Koji;
(Tsuchiura-shi, JP) ; YAMAMOTO; Shinjiro;
(Inashiki-gun Ami-machi, JP) ; KAMEOKA; Ryota;
(Ishioka-shi, JP) ; NARAZAKI; Akihiro;
(Tsukuba-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HITACHI CONSTRUCTION MACHINERY CO., LTD. |
Tokyo |
|
JP |
|
|
Appl. No.: |
17/623637 |
Filed: |
June 11, 2020 |
PCT Filed: |
June 11, 2020 |
PCT NO: |
PCT/JP2020/023097 |
371 Date: |
December 29, 2021 |
International
Class: |
E02F 9/24 20060101
E02F009/24; E02F 9/20 20060101 E02F009/20; E02F 9/26 20060101
E02F009/26; E02F 9/22 20060101 E02F009/22 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 25, 2019 |
JP |
2019-174667 |
Claims
1. A construction machine comprising: an actuator; an operation
device for instructing the actuator to operate: 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; wherein
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.
2. The construction machine according to claim 1, further
comprising: an operation lock device switchable between a locked
position for inhibiting operation of the actuator and an unlocked
position for permitting operation of the actuator, wherein the
predetermined condition includes switching of the operation lock
device from the unlocked position to the locked position.
3. The construction machine according to claim 1, wherein the
predetermined condition includes continuation of a state in which
the obstacle sensor does not detect an obstacle over a
predetermined period of time.
4. The construction machine according to claim 1, wherein the
controller is further configured to have a permanent cancelation
mode that is a control mode for permanently canceling operation
limiting control, determine in the normal mode whether the
controller is to shift to the temporary cancelation mode or the
permanent cancelation mode depending on how the control canceling
device is operated, and shift, in the permanent cancelation mode,
to the normal mode in response to operation of the control
canceling device.
5. The construction machine according to claim 4, wherein the
control canceling device includes a momentary pushbutton switch,
the controller is configured to shift to the temporary cancelation
mode in a case where a continuously pressed time of the pushbutton
switch is shorter than a predetermined period of time in the normal
mode, and shift to the permanent cancelation mode in a case where
the continuously pressed time of the pushbutton switch is equal to
or longer than the predetermined period of time in the normal
mode.
6. The construction machine according to claim 1, further
comprising: an operation sensor for detecting whether the operation
device is operated or not, wherein the controller is configured to
shift to the temporary cancelation mode if the operation sensor has
detected operation of the operation device continuously over a
predetermined period of time or longer while the obstacle sensor is
detecting an obstacle, other than in response to operation of the
control canceling device, in the normal mode.
Description
TECHNICAL FIELD
[0001] 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.
BACKGROUND ART
[0002] One form of accident caused by a construction machine is
assumed to be physical contact between the construction machine and
a worker in the periphery thereof. As means for avoiding causing
accidents, there have been proposed many systems for detecting an
obstacle (a person or an object), in the periphery by sensors and
indicating the obstacle to an operator and also many construction
machines and controllers thereof for limiting the speed at which a
vehicle body operates and automatically stopping the vehicle body
when an obstacle is detected in the periphery.
[0003] However, in actual situations where a construction machine
is to operate, it 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.
[0004] Apart from the above situations, in a case where it is
difficult to remove an obstacle away from a construction machine
when the construction machine detects the obstacle and operation
limitation is enabled, a need arises to move the construction
machine from the site with the obstacle being detected.
[0005] In view of such a situation, there has been a 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. When 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.
[0006] 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.
PRIOR ART DOCUMENT
Patent Document
[0007] Patent Document 1: PCT Patent Publication No.
WO2018/105527
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0008] 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.
[0009] According to the conventional art including 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.
[0010] Furthermore, although 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.
[0011] If a function to detect a peripheral obstacle is good enough
to detect only an obstacle that needs to be really detected (e.g.,
a person who unexpectedly enters a work area), then any situations
where operation limitation is to be canceled do not essentially
arise during normal work, and may be referred to as irregular.
However, 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.
[0012] 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.
[0013] When the operator cancels the limitation on operation in
order not to lower operability, as disclosed in the background art,
the construction machine is able to work, as in the past, with no
limitation on operation even if there is an obstacle in the
periphery. However, inasmuch as the function to avoid an accident
due to contact between the construction machine and a peripheral
worker does not work naturally, a problem arises in that safety
does not increase as originally intended.
[0014] After the operator has canceled the limitation on operation
and done necessary work, the operator should effectively reinstate
the limitation on operation each time it is required, depending on
the environment in which the construction machine operates. In the
event that 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.
[0015] 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.
Means for Solving the Problems
[0016] In order to accomplish the above object, there is provided
according to the present invention 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. In the construction machine, 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.
[0017] According to the present invention, as described above,
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. In addition, 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.
Advantages of the Invention
[0018] 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] 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.
[0020] FIG. 2 is a view illustrating positions where obstacle
sensors are installed and detection areas according to the first
embodiment of the present invention.
[0021] FIG. 3 is a diagram illustrating a system configuration
according to the first embodiment of the present invention.
[0022] 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.
[0023] FIG. 5 is a flowchart of a processing sequence of a
detection determining section according to the first embodiment of
the present invention.
[0024] 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.
[0025] 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.
[0026] 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.
[0027] 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.
[0028] 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.
[0029] 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.
[0030] FIG. 12 is a flowchart of a processing sequence of an
operation limiting commanding section according to the first
embodiment of the present invention.
[0031] FIG. 13 is a flowchart of a processing sequence of a
solenoid valve actuating section according to the first embodiment
of the present invention.
[0032] FIG. 14 is a flowchart of a processing sequence of an engine
rotation control section according to the first embodiment of the
present invention.
[0033] 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.
MODES FOR CARRYING OUT THE INVENTION
[0034] Embodiments of the present invention will be described
hereinbelow with reference to the drawings. In the drawings,
equivalent components are denoted by identical referenced
characters throughout views, and redundant description thereof will
be omitted.
First Embodiment
[0035] (Description of a Hydraulic Excavator)
[0036] 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.
[0037] In FIG. 1, 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.
[0038] 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.
[0039] 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).
[0040] The front implement 3 includes a boom 3a, an arm 3b, and a
bucket 3c. The boom 3a is vertically moved by a boom cylinder 3d.
The arm 3b is operated toward a dumping side (opening side) or a
crowding side (gathering side) by an arm cylinder 3e. The bucket 3c
is operated toward the dumping side or the crowding side by a
bucket cylinder 3f.
[0041] (Description Regarding Obstacle Sensors)
[0042] 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.
[0043] (Description Regarding Obstacle Sensors and Detection
Areas)
[0044] FIG. 2 is a view illustrating positions where the obstacle
sensors (3D sensors 6 through 9) are installed and the detection
areas thereof.
[0045] 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.
[0046] Using the detection ranges of the 3D sensors, there are
established detection areas for lowering the possibility of an
accident caused by contact between the construction machine, i.e.,
the hydraulic excavator, that is about to move and a peripheral
worker. Specifically, 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.
[0047] 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.
[0048] (Description Regarding a State Regarded as Obstacle
Detection)
[0049] The 3D sensors 6 through 9 determine whether an obstacle is
present in the respective detection areas 10 through 13 or not.
[0050] According to the present embodiment, 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.
[0051] (Description of a System Configuration; Components of an
Ordinary Hydraulic Excavator)
[0052] FIG. 3 is a diagram illustrating a system configuration
according to the present embodiment.
[0053] The cabin 4 of the hydraulic excavator according to the
present embodiment 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.
[0054] The cabin 4 of the hydraulic excavator also houses therein
the operation devices for controlling the hydraulic excavator to
operate in various ways. In FIG. 3, 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.
[0055] The hydraulic excavator according to the present embodiment
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.
[0056] 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.
[0057] Regarding engine rotational speed control, for example, 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. As 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.
[0058] A hydraulic operating fluid delivered from a
variable-displacement-type hydraulic pump 24 that is actuated by
the engine 22 flows through a control valve 25 that controls a
fluid flow toward hydraulic actuators and is supplied to a travel
motor 3h, a swing motor 3g, the boom cylinder 3d, the arm cylinder
3e, and the bucket cylinder 3f as these hydraulic actuators.
[0059] Normally, the hydraulic excavator includes a plurality of
hydraulic pumps for simultaneously operating a plurality of
hydraulic actuators. In FIG. 3, one of those hydraulic pumps is
illustrated as a representative hydraulic pump.
[0060] 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.
[0061] 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.
[0062] 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.
[0063] 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).
[0064] 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.
[0065] 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.
[0066] 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.
[0067] 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.
[0068] 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.
[0069] 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.
[0070] When the lock valve 28 is in the interruption position, the
swing operation lever 19, the travel operation lever 20, and the
front implement operation lever 21 are not supplied with the pilot
valve primary pressure. Thus, even when the operation levers 19
through 21 are operated, since the pilot valve secondary pressure
does not increase and is unable to shift the spools in the control
valve 25, the vehicle body is operationally disabled in whole.
[0071] When the lock valve 28 is in the fluid communication
position, 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. Thus, depending on operation of
the operation levers 19 through 21, 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.
[0072] 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.
[0073] 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.
[0074] 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.
[0075] 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.
[0076] 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.
[0077] 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.
[0078] (Description of a System Configuration; Part of the
Configuration as a Peripheral Detection and Operation Limiting
System as a Premise)
[0079] 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.
[0080] 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.
[0081] 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.
[0082] 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.
[0083] 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.
[0084] Moreover, 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.
[0085] 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.
[0086] (Description of a System Configuration; Additional Aspect
According to the Present Invention)
[0087] According to the present embodiment, the cabin 4 houses
therein a control canceling switch 36 including a momentary
pushbutton switch as a control canceling device.
[0088] 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.
[0089] 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.
[0090] If the 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.
[0091] (Description of a Controller Makeup)
[0092] FIG. 4 is a diagram illustrating the makeup of the
controller 14 for limiting operation of the vehicle body upon
detection of an obstacle.
[0093] 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.
[0094] 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.
[0095] 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.
[0096] 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.
[0097] 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).
[0098] (Description of Details of the Control Sections)
[0099] Details of the control sections illustrated in FIG. 4 will
be described below with reference to FIGS. 5 through 14.
[0100] (Description of Details of the Control Sections; the
Detection Determining Section)
[0101] FIG. 5 is a flowchart of a processing sequence of the
detection determining section 40.
[0102] First, 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 S1). 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 v1 that is a
variable to "detection" (step S6).
[0103] If the 3D sensor 6 has not detected an item in the detection
area 10, then the detection determining section 40 determines
whether the 3D sensor 7 has detected an item in the detection area
11 or not (step S2). 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 v1 that is a variable to "detection"
(step S6).
[0104] If the 3D sensor 7 has not detected an item in the detection
area 11, then the detection determining section 40 determines
whether the 3D sensor 8 has detected an item in the detection area
12 or not (step S3). 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 v1 that is a variable to "detection"
(step S6).
[0105] If the 3D sensor 8 has not detected an item in the detection
area 12, then the detection determining section 40 determines
whether the 3D sensor 9 has detected an item in the detection area
13 or not (step S4). 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 v1 that is a variable to "detection"
(step S6).
[0106] If an item has not been detected in any of the detection
areas 10 through 13, then the detection determining section 40
determines that the vehicle body is in a non-detection state, and
sets the obstacle detection state v1 that is a variable to
"non-detection" (step S5).
[0107] (Description of Details of the Control Sections; the
Operation State Determining Section)
[0108] 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.
[0109] First, 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 C1 (e.g., 0.5 MPa) (step S33).
If the swing operation pressure is equal to or higher than the
operation ON threshold value C1, then the operation state
determining section 41 determines that a swing operation is
performed, and sets a swing operation state v10 that is a variable
to "during operation" (step S34). If the swing operation pressure
is lower than the operation ON threshold value C1, then the
operation state determining section 41 determines that a swing
operation is not performed, and sets the swing operation state v10
that is a variable to "non-operation" (step S35).
[0110] Next, 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 C1 (e.g., 0.5 MPa) (step
S36). If the travel operation pressure is equal to or higher than
the operation ON threshold value C1, then the operation state
determining section 41 determines that a travel operation is
performed, and sets a travel operation state v11 that is a variable
to "during operation" (step S37). If the travel operation pressure
is lower than the operation ON threshold value C1, then the
operation state determining section 41 determines that the travel
operation is not performed, and sets the travel operation state v11
that is a variable to "non-operation" (step S38).
[0111] Then, 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 C1 (e.g., 0.5 MPa)
(step S39). If the front implement operation pressure is equal to
or higher than the operation ON threshold value C1, then the
operation state determining section 41 determines that the front
implement is operated, and sets a front implement operation state
v12 that is a variable to "during operation" (step S40). If the
front implement operation pressure is lower than the operation ON
threshold value C1, then the operation state determining section 41
determines that the front implement is not operated, and sets the
front implement operation state v12 that is a variable to
"non-operation" (step S41).
[0112] 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.
[0113] First, the operation state determining section 41 determines
whether the swing operation state v10 represents "during operation"
or not (step S7). If the swing operation state v10 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 v2 that is a variable to "during
operation" (step S11).
[0114] If the swing operation state v10 does not represent "during
operation" (if the swing operation state v10 represents
"non-operation"), then the operation state determining section 41
determines whether the travel operation state v11 represents
"during operation" or not (step S8). If the travel operation state
v11 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 v2 that
is a variable to "during operation" (step S11).
[0115] If the travel operation state v11 does not represent "during
operation" (if the travel operation state v11 represents
"non-operation"), then the operation state determining section 41
determines whether the front implement operation state v12
represents "during operation" or not (step S9). If the front
implement operation state v12 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 v2 that is a variable to "during operation" (step
S11).
[0116] If all of the swing operation state v10, the travel
operation state v11, and the front implement operation state v12 do
not represent "during operation" (if all of the swing operation
state v10, the travel operation state v11, and the front implement
operation state v12 represent "non-operation"), then the operation
state determining section 41 determines that the vehicle body is in
a non-operation state, and sets the vehicle body operation state v2
that is a variable to "non-operation" (step S10).
[0117] (Description of Details of the Control Sections; the
Controlled State Switching Determining Section)
[0118] FIG. 8 is a flowchart of an entire processing sequence of
the controlled state switching determining section 38.
[0119] The controlled state switching determining section 38
selects a processing sequence to be carried out depending on
whether a control mode state v3 at present (in a preceding step of
the control sequence) represents "normal," "temporary cancelation,"
or "permanent cancelation" (step S12).
[0120] If the control mode state v3 at present represents "normal,"
then the controlled state switching determining section 38 carries
out a process of determining switching from a normal mode (step
S13). If the control mode state v3 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 S14). If the control mode state v3
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
S15).
[0121] The control mode state v3 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 v3 representing "normal."
[0122] FIG. 9 is a flowchart of a processing sequence of the
process of determining switching from the normal mode (step S13),
as a subroutine of the controlled state switching determining
section 38.
[0123] 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."
[0124] In the determination of switching from the normal mode (step
S13), first, 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 S16).
[0125] If the controlled state switching determining section 38
determines that the answer to step S16 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 v3 from
"normal."
[0126] 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 t1 (step S17).
[0127] Then, 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
S18). 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 t1 is equal to
or longer than a cancelation mode determining time T1 (e.g., 2
seconds) (step S19). If the control canceling switch ON time t1 is
shorter than the cancelation mode determining time T1, then the
processing sequence goes back to step S18 and is repeated.
[0128] If the controlled state switching determining section 38
determines that the control canceling switch state is not ON in
step S18, 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 t1 reaches the cancelation mode
determining time T1, then the controlled state switching
determining section 38 switches the control mode state v3 to
"temporary cancelation" (step S20).
[0129] If the control canceling switch ON time t1 becomes equal to
or longer than the cancelation mode determining time T1 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 t1 reaches the
cancelation mode determining time T1, then the controlled state
switching determining section 38 switches the control mode state v3
to "permanent cancelation" (step S21).
[0130] After having switched the control mode state v3 from
"normal" in step S20 or step S21, the controlled state switching
determining section 38 stops counting the control canceling switch
ON time t1 and resets the control canceling switch ON time t1 to a
default value (0) (step S22).
[0131] FIG. 10 is a flowchart of a processing sequence of the
process of determining switching from the temporary cancelation
mode (step S14), as a subroutine of the controlled state switching
determining section 38.
[0132] 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.
[0133] According to the present embodiment, when the lock lever
disposed in the cabin 4 is in the locked position and the lock
switch 15 is not pressed, a lock switch state is "OFF." When the
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.
[0134] According to the present embodiment, further, when the lock
lever disposed in the cabin 4 is in the unlocked position and the
lock switch 15 is pressed, the lock switch state is "ON." When 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.
[0135] In the process of determining switching from the temporary
cancelation mode (step S14), first, the controlled state switching
determining section 38 starts counting a non-detection time t2
(step S23).
[0136] Then, 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 S24).
[0137] If the controlled state switching determining section 38
determines that the answer to step S24 is YES, then the controlled
state switching determining section 38 switches the control mode
state v3 to "normal" (step S25). Thereafter, the controlled state
switching determining section 38 stops counting the non-detection
time t2 and resets the non-detection time t2 to a default value (0)
(step S26), after which the processing sequence is ended.
[0138] 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 S27).
[0139] If the controlled state switching determining section 38
determines that the answer to step S27 is YES, then the controlled
state switching determining section 38 switches the control mode
state v3 to "normal" (step S25). Thereafter, the controlled state
switching determining section 38 stops counting the non-detection
time t2 and resets the non-detection time t2 to the default value
(0) (step S26), after which the processing sequence is ended.
[0140] If the lock switch 15 is not in the locked position and the
lock switch state remains to be ON, then the controlled state
switching determining section 38 determines whether the obstacle
detection state v1 represents "non-detection" or not (step S28). If
the obstacle detection state v1 does not represent "non-detection,"
i.e., if the obstacle detection state v1 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 v3 from "temporary
cancelation," and resets the non-detection time t2 to the default
value (0) (step S29). The processing sequence goes back to step
S24, and the determining process is continued.
[0141] If the obstacle detection state v1 represents
"non-detection" in step S28, then the controlled state switching
determining section 38 determines whether or not the non-detection
time t2 is equal to or longer than a control mode return time T2
(e.g., 30 seconds) (step S30). If the non-detection time t2 is
shorter than the control mode return time T2, then the processing
sequence goes back to step S24, and the determining process is
continued.
[0142] If the non-detection time t2 becomes equal to or longer than
the control mode return time T2 without detecting an obstacle, then
the controlled state switching determining section 38 switches the
control mode state v3 to "normal" (step S25). Thereafter, the
controlled state switching determining section 38 stops counting
the non-detection time t2 and resets the non-detection time t2 to
the default value (0) (step S26), after which the processing
sequence is ended.
[0143] FIG. 11 is a flowchart of a processing sequence of a process
of determining switching from the permanent cancelation mode (step
S15), as a subroutine of the controlled state switching determining
section 38.
[0144] In step S15, 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 S31).
[0145] If the controlled state switching determining section 38
determines that the answer to step S31 is YES, then the controlled
state switching determining section 38 switches the control mode
state v3 to "normal" (step S32), 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 v3 from "permanent cancelation,"
after which the processing sequence is ended.
[0146] (Description of Details of the Control Sections; the
Operation Limiting Command Section)
[0147] FIG. 12 is a flowchart of a processing sequence of the
operation limiting command section 39.
[0148] First, the operation limiting command section 39 determines
whether the control mode state v3 represents "normal" or not (step
S42). If the control mode state v3 represents "normal" (if the
control mode state v3 does not represent "temporary cancelation" or
"permanent cancelation"), then the operation limiting command
section 39 determines whether the obstacle detection state v1
represents "detection" or not (step S43). If there is an item (a
person or an object) in the periphery of the vehicle body and the
obstacle detection state v1 represents "detection," then the
operation limiting command section 39 sets a rotational speed
command v6 to "limited rotational speed" (e.g., 800 rpm) (step
S44).
[0149] In this manner, 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. When the vehicle
body has been operating at a high engine rotational speed (e.g.,
1800 rpm) during normal work, as the engine rotational speed is
lowered upon obstacle detection, the operator can notice the
detection through a bodily sensation in addition to a warning or
display, so that higher safety can be achieved.
[0150] Further, while an obstacle is being detected, since the
engine rotational speed is limited and the same work cannot be
continued as it is by ignoring the obstacle detection, the operator
is prompted to stop the work and check safety in the periphery.
[0151] Then, the operation limiting command section 39 determines
whether the swing operation state v10 represents "non-operation" or
not (step S45). If the swing operation state v10 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 v4 to "interruption pressure" (e.g., 0
MPa) (step S46).
[0152] In this fashion, swing operation is made impossible through
the processing of the solenoid valve actuating section 42 to be
described later. By stopping a swinging start while an obstacle is
present in the periphery of the vehicle body, it is possible to
lower the possibility of an accident due to contact between the
vehicle body and a peripheral worker when the hydraulic excavator
is about to move.
[0153] Next, the operation limiting command section 39 determines
whether the travel operation state v11 represents "non-operation"
or not (step S47). If the travel operation state v11 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 v5 to "interruption pressure" (e.g.,
0 MPa) (step S48).
[0154] In this fashion, travel operation is made impossible through
the processing of the solenoid valve actuating section 42 to be
described later. By stopping a traveling start while an obstacle is
present in the periphery of the vehicle body, it is possible to
lower the possibility of an accident due to contact between the
vehicle body and a peripheral worker when the hydraulic excavator
is about to move.
[0155] As described above, upon obstacle detection, vehicle body
operation limitation for limiting vehicle body operation is
enabled.
[0156] Next, a process of determining cancelation of the vehicle
body operation limitation and a control process will be described
below.
[0157] If an item (a person or an object) is not detected in the
periphery of the vehicle body and the obstacle detection state v1
does not represent "detection" in step S43 (the obstacle detection
state v1 represents "non-detection" in step S43), the operation
limiting command section 39 determines whether the lock switch
state is OFF or not (step S49). If the lock lever is in the locked
position and the lock switch state is OFF while no obstacle is
being detected, the operation limiting command section 39 sets the
rotational speed command v6 to "maximum rotational speed" (e.g.,
2000 rpm) (step S50), sets the swing stop command v4 to "open
pressure" (e.g., 4 MPa) (step S51), and sets the travel stop
command v5 to "open pressure" (e.g., 4 MPa) (step S52).
[0158] If the lock lever is in the unlocked position and the lock
switch state is ON (the lock switch state is not OFF), the vehicle
body operation limitation remains enabled even if the obstacle
detection state v1 no longer represents "detection."
[0159] 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.
[0160] (Description of Details of the Control Sections; the
Solenoid Valve Actuating Section)
[0161] FIG. 13 is a flowchart of a processing sequence of the
solenoid valve actuating section 42.
[0162] 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 v4 and the travel stop command v5 as calculated results
from the operation limiting command section 39.
[0163] First, the solenoid valve actuating section 42 determines
whether the swing stop command v4 represents "interruption
pressure" or not (step S53). If the swing stop command v4
represents "interruption pressure," then the solenoid valve
actuating section 42 sets a swing pilot pressure interruption
solenoid valve current v7 to "interruption current" (e.g., 600 mA)
(step S54). If the swing stop command v4 does not represent
"interruption pressure" (if the swing stop command v4 represents
"open pressure"), then the solenoid valve actuating section 42 sets
the swing pilot pressure interruption solenoid valve current v7 to
"open current" (e.g., 0 mA) (step S55).
[0164] Then, the solenoid valve actuating section 42 determines
whether the travel stop command v5 represents "interruption
pressure" or not (step S56). If the travel stop command v5
represents "interruption pressure," then the solenoid valve
actuating section 42 sets a travel pilot pressure interruption
solenoid valve current v8 to "interruption current" (e.g., 600 mA)
(step S57). If the travel stop command v5 does not represent
"interruption pressure" (if the travel stop command v5 represents
"open pressure"), then the solenoid valve actuating section 42 sets
the travel pilot pressure interruption solenoid valve current v8 to
"open current" (e.g., 0 mA) (step S58).
[0165] 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 v7 and the travel pilot pressure interruption
solenoid valve current v8, thereby actuating the swing pilot
pressure interruption solenoid valve 34 and the travel pilot
pressure interruption solenoid valve 35 (step S59).
[0166] (Description of Details of the Control Sections; the Engine
Rotation Control Section)
[0167] FIG. 14 is a flowchart of a processing sequence of the
engine rotation control section 43.
[0168] 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 v9 through the CAN communication to the engine
controller 23, thereby achieving an actual engine rotational speed
required of the vehicle body.
[0169] Although not described in detail according to the present
embodiment, a required rotational speed according to a processing
sequence common with a conventional hydraulic excavator, other than
the rotational speed command v6 sent from the operation limiting
command section 39, is calculated as a reference required
rotational speed v13 by a processing sequence not illustrated in
FIG. 14 (step S60). The rotational speed command v6 and the
reference required rotational speed v13 are compared with each
other at a final stage of the processing sequence of the engine
rotation control section 43.
[0170] Following the calculation of the reference required
rotational speed v13 (step S60), the engine rotation control
section 43 determines whether the rotational speed command v6 sent
from the operation limiting command section 39 is larger than the
reference required rotational speed v13 (step S61).
[0171] When vehicle body operation limitation is not enabled, since
the rotational speed command v6 is "maximum rotational speed"
(e.g., 2000 rpm) larger than the reference required rotational
speed v13, the engine rotation control section 43 sets the target
engine rotational speed v9 to "reference required rotational speed
v13," thereby making the hydraulic excavator usable as an ordinary
hydraulic excavator (step S62).
[0172] When vehicle body operation limitation is enabled, since the
rotational speed command v6 is "limited rotational speed" (e.g.,
800 rpm) equal to or smaller than the reference required rotational
speed v13, the engine rotation control section 43 sets the target
engine rotational speed v9 to "rotational speed command v6,"
thereby forcefully limiting the engine rotational speed to limit
operation of the vehicle body (step S63).
[0173] (Advantages of the First Embodiment)
[0174] According to the present embodiment, a hydraulic excavator
includes actuators 3d through 3h, operation devices (operation
levers 19 through 21) for instructing the actuators 3d through 3h
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 3d
through 3h 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 canceling switch 36) is satisfied while in the temporary
cancelation mode.
[0175] According to the present embodiment, 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. Thus, 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. In addition, 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.
[0176] Further, 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 3d through 3h and an
unlocked position (fluid communication position) for permitting
operation of the actuators 3d through 3h, 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).
[0177] With the above arrangement, 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. Moreover, as the
controller 14 returns from the temporary cancelation mode to the
normal mode by operating the lock valve 28 (operation lock device)
as performed on conventional construction machines, 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.
[0178] According to the present embodiment, further, 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 T2).
[0179] With the above arrangement, since the controller 14 returns
from the temporary cancelation mode to the normal mode when the
control mode return time T2 (e.g., 30 seconds) has elapsed while
the obstacle detection state v1 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.
[0180] The control mode return time T2 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.
[0181] For example, while the hydraulic excavator is carrying out
dump truck loading work including repeated actions of excavating,
90.degree. swinging, soil dropping, and returning, it is assumed
that a gravel mound to work on is to be detected as a peripheral
obstacle only upon soil dropping. At this time, "detection" and
"non-detection" alternately occur with respect to the obstacle in
ganged relation to operation of the hydraulic excavator. In a case
where the operator sets the control mode return time T2 to a value
shorter than the total time used for returning, excavating, and
90.degree. swinging, even if the operator has temporarily canceled
vehicle body operation limitation and worked, a situation arises
where "the control mode return time T2 elapses" in the state of
"non-detection" during one cycle, allowing the controller 14 to
return from the temporary cancelation mode to the normal mode. In
this case, the operator needs to press the control canceling switch
36 per cycle, resulting in significantly reduced operability. In
order to secure operability, the operator is expected to use the
hydraulic excavator in the permanent cancelation mode where the
controller 14 does not automatically return to the normal mode.
However, using the hydraulic excavator in the permanent cancelation
mode fails to increase safety as originally intended.
[0182] Conversely, in a case where the operator sets the control
mode return time T2 to an unnecessarily long value (e.g., 10
minutes) by placing too much priority on preventing the controller
14 from automatically returning to the normal mode during work,
since the hydraulic excavator operates in a control canceled state
for a long period of time even after the periphery has been cleared
of the item, increased safety as originally intended cannot be
achieved.
[0183] Consequently, the control mode return time T2 is established
taking into account operability and safety sufficiently in
advance.
[0184] According to the present embodiment, moreover, 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
(control canceling switch 36) 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 t1) of the control canceling switch 36 is shorter
than a predetermined period of time (cancelation mode determining
time T1) in the normal mode, and shifts to the permanent
cancelation mode in a case where the continuously pressed time
(control canceling switch ON time t1) of the control canceling
switch 36 is equal to or longer than the predetermined period of
time (cancelation mode determining time T1) in the normal mode.
[0185] It is thus possible for the controller to select shifting to
the temporary cancelation mode or shifting to the permanent
cancelation mode through operation of the single control canceling
switch 36.
[0186] According to the present embodiment arranged as described
above, it is possible 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 item required for work is
present in the periphery.
Second Embodiment
[0187] 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.
[0188] FIG. 15 is a flowchart of an additional processing sequence
of a process of determining switching from a normal mode (step
S13), as a subroutine of a controlled state switching determining
section 38 according to the present embodiment. Specifically, 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 S13).
[0189] First, the controlled state switching determining section 38
starts counting a during-detection operation time t3 (step
S64).
[0190] Then, the controlled state switching determining section 38
determines whether the obstacle detection state v1 represents
"detection" or not (step S65). If the obstacle detection state v1
does not represent "detection" (if the obstacle detection state v1
represents "non-detection"), then the controlled state switching
determining section 38 stops counting the during-detection
operation time t3, and resets the during-detection operation time
t3 to a default value (0) (step S69), after which the processing
sequence is ended.
[0191] If the obstacle detection state v1 represents "detection,"
then the controlled state switching determining section 38
determines whether the vehicle body operation state v2 represents
"during operation" or not (step S66). If the vehicle body operation
state v2 does not represent "during operation" (if the vehicle body
operation state v2 represents "non-operation"), then the controlled
state switching determining section 38 stops counting the
during-detection operation time t3, and resets the during-detection
operation time t3 to a default value (0) (step S69), after which
the processing sequence is ended.
[0192] If the vehicle body operation state v2 represents
"during-operation," then the controlled state switching determining
section 38 determines whether or not the during-detection operation
time t3 is equal to or longer than an automatic temporary
cancelation shifting time T3 (e.g., 5 seconds) (step S67).
[0193] If the during-detection operation time t3 has reached the
automatic temporary cancelation shifting time T3, then the
controlled state switching determining section 38 sets the control
mode state v3 to "temporary cancelation" (step S68), stops counting
the during-detection operation time t3, and resets the
during-detection operation time t3 to a default value (0) (step
S69), after which the processing sequence is ended.
[0194] If the during-detection operation time t3 is shorter than
the automatic temporary cancelation shifting time T3, then the
processing sequence goes back to step S65 and repeats the process
of determining the obstacle detection state v1 and the process of
determining the vehicle body operation state v2.
[0195] The additional processing sequence of the process of
determining switching from the normal mode, as illustrated in FIG.
15, 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.
[0196] (Advantages of the Second Embodiment)
[0197] According to the present embodiment, 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 T3) 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.
[0198] When an obstacle is detected, 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.
However, even though the obstacle is detected, 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.
[0199] According to the first embodiment of the present invention,
the control canceling switch 36 can cancel vehicle body operation
limitation as a way of meeting such a need.
[0200] However, in a case where the 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.
[0201] From the standpoint of prompting the operator to check
safety in the periphery upon obstacle detection, it is effective
for the operator to take his/her hands off the operation levers 19
through 21 in order to press the control canceling switch 36.
[0202] However, there may be predictable situations where,
especially while working on sloped terrain or a road shoulder of
muddy or irregular terrain, the vehicle body should not be stopped
immediately, but should be moved a certain distance away from an
obstacle and then stopped, thereby avoiding a new risk due to
falling over, falling down, or slippage.
[0203] In certain limited situations, it may be better for the
operator to keep moving the vehicle body until it can be stopped
reliably in safety, rather than taking his/her hands off the
operation levers 19 through 21 to press the control canceling
switch 36 and stopping the vehicle body.
[0204] According to the present embodiment, even when an obstacle
is detected, since 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.
[0205] Of course, inasmuch as when an obstacle is detected, it is
desirable, in principle, for the operator to press the control
canceling switch 36 to shift to the temporary cancelation mode
after having stopped the vehicle body in safety as quickly as
possible and checked safety in the vicinity, it is separately
necessary to prompt the operator to pay attention to the fact that
the function added according to the present embodiment is to be
used as an emergency function.
[0206] While the embodiments of the present invention have been
described hereinbefore, the present invention is not limited to the
above embodiments and covers various modifications. For example,
the above embodiments have been described in detail for easier
understanding of the present invention; the present invention may
not necessarily be limited to those including all the details
described above. It is possible to add parts of some embodiments to
those of other embodiments, and also to delete parts of some
embodiments or replace them with parts of other embodiments.
DESCRIPTION OF REFERENCE CHARACTERS
[0207] 1: Lower track structure [0208] 2: Upper swing structure
[0209] 3: Front implement [0210] 3a: Boom [0211] 3b: Arm [0212] 3c:
Bucket [0213] 3d: Boom cylinder (actuator) [0214] 3e: Arm cylinder
(actuator) [0215] 3f: Bucket cylinder (actuator) [0216] 3g: Swing
motor (actuator) [0217] 3h: Travel motor (actuator) [0218] 4: Cabin
[0219] 5: Display device [0220] 6: 3D sensor (obstacle sensor)
[0221] 7: 3D sensor (obstacle sensor) [0222] 8: 3D sensor (obstacle
sensor) [0223] 9: 3D sensor (obstacle sensor) [0224] 10: Detection
area [0225] 11: Detection area [0226] 12: Detection area [0227] 13:
Detection area [0228] 14: Vehicle body controller (controller)
[0229] 15: Lock switch [0230] 16: Switch box [0231] 17: Monitor
controller [0232] 18: Periphery detection monitor [0233] 19: Swing
operation lever (operation device) [0234] 20: Travel operation
lever (operation device) [0235] 21: Front implement operation lever
(operation device) [0236] 22: Engine [0237] 23: Engine controller
[0238] 24: Hydraulic pump [0239] 25: Control valve [0240] 26:
Hydraulic fluid source [0241] 27: Pump regulator [0242] 28: Lock
valve (operation lock device) [0243] 29: Swing operation pressure
sensor (operation sensor) [0244] 30: Travel operation pressure
sensor (operation sensor) [0245] 31: Front implement operation
pressure sensor (operation sensor) [0246] 32: Pump delivery
pressure sensor [0247] 33: Pump flow rate control pressure sensor
[0248] 34: Swing pilot pressure interruption solenoid valve [0249]
35: Travel pilot pressure interruption solenoid valve [0250] 36:
Control canceling switch (control canceling device) [0251] 37:
Operation limiting control section [0252] 38: Controlled state
switching determining section [0253] 39: Operation limiting command
section [0254] 40: Detection determining section [0255] 41:
Operation state determining section [0256] 42: Solenoid valve
actuating section [0257] 43: Engine rotation control section
* * * * *