U.S. patent application number 14/940934 was filed with the patent office on 2017-05-18 for hydraulic system having diagnostic mode of operation.
This patent application is currently assigned to Caterpillar Inc.. The applicant listed for this patent is Caterpillar Inc.. Invention is credited to Matthew J. BESCHORNER, Darren A. BLUM, Naoto FUNABIKI, Brett J. JANSON.
Application Number | 20170138018 14/940934 |
Document ID | / |
Family ID | 58690883 |
Filed Date | 2017-05-18 |
United States Patent
Application |
20170138018 |
Kind Code |
A1 |
BESCHORNER; Matthew J. ; et
al. |
May 18, 2017 |
HYDRAULIC SYSTEM HAVING DIAGNOSTIC MODE OF OPERATION
Abstract
A hydraulic system is disclosed for use with. a machine. The
hydraulic system may have an actuator, a valve associated with the
actuator, at least one sensor configured to generate signals
indicative of performance parameters of the hydraulic system, and a
controller. The controller may be configured to determine at least
one of a diagnostic movement and position of at least one of the
fluid actuator and valve required to perform a health cheek, and to
correlate the signals generated only during completion of the
diagnostic movement or only when the at least one of the fluid
actuator and valve are in the diagnostic position to values of the
performance parameters. The controller may also be configured to
make a comparison of the values of the performance parameters to
expected values, and to determine a health of the hydraulic system
based on the comparison.
Inventors: |
BESCHORNER; Matthew J.;
(Plainfield, IL) ; FUNABIKI; Naoto; (Hyougo-ken,
JP) ; JANSON; Brett J.; (Hanna City, IL) ;
BLUM; Darren A.; (Plainfield, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Caterpillar Inc. |
Peoria |
IL |
US |
|
|
Assignee: |
Caterpillar Inc.
Peoria
IL
|
Family ID: |
58690883 |
Appl. No.: |
14/940934 |
Filed: |
November 13, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F15B 2211/6313 20130101;
F15B 2211/20546 20130101; E02F 9/267 20130101; F15B 2211/6336
20130101; F15B 2211/855 20130101; F15B 2211/857 20130101; F15B
2211/7142 20130101; E02F 9/2289 20130101; E02F 9/2292 20130101;
G05B 19/0425 20130101; F15B 2211/634 20130101; F15B 19/005
20130101; F15B 2211/20576 20130101; F15B 2211/7135 20130101; G05B
19/46 20130101; F15B 2211/30595 20130101; E02F 9/2242 20130101;
E02F 9/2235 20130101; F15B 2211/6343 20130101; F15B 2211/6309
20130101; E02F 9/2296 20130101; F15B 2211/87 20130101 |
International
Class: |
E02F 9/26 20060101
E02F009/26; E02F 9/22 20060101 E02F009/22 |
Claims
1. A hydraulic system, comprising: a fluid actuator; a valve
associated with the fluid actuator; at least one sensor configured
to generate a signal indicative of a performance parameter of the
hydraulic system; and a controller in communication with the at
least one sensor and configured to: determine at least one of a
diagnostic movement and a diagnostic position of at least one of
the fluid actuator and the valve required to perform a health check
of the hydraulic system; correlate the signal generated only during
completion of the diagnostic movement or only when the at least one
of the fluid actuator and the valve are in the diagnostic position
to a value of the performance parameter; make a comparison of the
value of the performance parameter to an expected value; and
determine a health of the hydraulic system based on the
comparison.
2. The hydraulic system of claim 1, wherein the at least one sensor
is one of a pressure sensor, a position sensor, a displacement
sensor, and a speed sensor.
3. The hydraulic system of claim 1, wherein the at least one sensor
includes at least a first sensor located to sense a pressure inside
a chamber of the fluid actuator.
4. The hydraulic system of claim 3, wherein the at least one sensor
includes at least a second sensor configured to sense a pressure
differential across the valve.
5. The hydraulic system of claim 4, further including a pump
configured to direct pressurized fluid to the valve, wherein the at
least one sensor includes at least a third sensor configured to
sense a pressure differential across the pump.
6. The hydraulic system of claim 1, wherein the controller is
configured to adjust a result of the comparison for an age of the
hydraulic system.
7. The hydraulic system of claim 1, wherein the controller is
configured to determine the at least one of the diagnostic movement
and the diagnostic position based on a suspected malfunction of the
hydraulic system.
8. The hydraulic system of claim 1, wherein the controller is
manually triggered to perform the health check of the hydraulic
system.
9. The hydraulic system of claim 8, wherein the controller is
configured to instruct an operator to cause the at least one of the
fluid actuator and the valve to perform the diagnostic movement or
to achieve the diagnostic position.
10. The hydraulic system of claim 9, wherein the controller is
further configured to selectively recommend one of three possible
corrective actions based on the health of the hydraulic system.
11. The hydraulic system of claim 9, wherein the three possible
corrective actions include: a first level action, wherein the
operator is instructed to schedule a particular maintenance
activity to occur at a next regular service interval; a second
level action, wherein the operator is instructed to perform the
particular maintenance activity at a next convenient time; and a
third level action, wherein the operator is instructed to
immediately shut down the hydraulic system and perform the
particular maintenance activity.
12. The hydraulic system of claim 1, wherein the controller is
automatically triggered to perform the health check of the
hydraulic system based on a sensed performance parameter of the
hydraulic system.
13. The hydraulic system of claim 12, wherein the controller is
configured to automatically cause the at least one of the fluid
actuator and the valve to perform the diagnostic movement or to
achieve the diagnostic position.
14. The hydraulic system of claim 13, wherein the controller is
further configured to automatically implement one of three possible
corrective actions based on the health of the hydraulic system.
15. The hydraulic system of claim 9, wherein the three possible
corrective actions include: a first level action, wherein the
controller automatically schedules a particular maintenance
activity to occur at a next regular service interval; a second
level action, Wherein the controller automatically schedules the
particular maintenance activity to occur at a next convenient time;
and a third level action, wherein the controller immediately shuts
down the hydraulic system and generates a request for the
particular maintenance activity to be performed before restart of
the hydraulic system.
16. The hydraulic system of claim 1, wherein the controller is
configured to continuously perform the health check of the
hydraulic system whenever the at least one of the fluid actuator
and the valve are in performance of the diagnostic movement or are
in the diagnostic position.
17. A method of determining a health of a hydraulic system having a
fluid actuator and a valve associated with the fluid actuator, the
method comprising: generating a signal indicative of a performance
parameter of the hydraulic system; determining at least one of a
diagnostic movement and a diagnostic position of at least one of
the fluid actuator and the valve required for diagnosing the health
of the hydraulic system; correlating the signal generated only
during completion of the diagnostic movement or only when the at
least one of the fluid actuator and the valve are in the diagnostic
position to a value of the performance parameter; making a
comparison of the value of the performance parameter to an expected
value; and determining the health of the hydraulic system based on
the comparison.
18. The method of claim 17, further including adjusting the
comparison based on an age of the hydraulic system.
19. The method of claim 17, wherein determining the at least one of
the diagnostic movement and the diagnostic position of the at least
one of the fluid actuator and the valve includes determining the at
least one of the diagnostic movement and the diagnostic position of
the at least one of the fluid actuator and the valve based on a
suspected malfunction of the hydraulic system.
20. A machine, comprising: a frame; a power source mounted to the
frame; a linkage arrangement; a fluid actuator configured to move
the linkage arrangement; a pump; a sump; a valve disposed between
the fluid actuator, the pump, and the sump; a plurality of sensors
configured to generate signals indicative of performance parameters
of the machine; and a controller in communication with the
plurality of sensors and configured to: receive input indicative of
a suspected hydraulic component malfunction; determine at least one
of a diagnostic movement and a diagnostic position of at least one
of the fluid actuator and the valve required to performe a health
check of the machine based on the suspected hydraulic component
malfunction; correlate the signals generated only during completion
of the diagnostic movement or only when the at least one of the
fluid actuator and the valve are in the diagnostic position to
values of the performance parameters; determine an age of the
machine; make an age-adjusted comparison of the values of the
performance parameters to expected values; and determine a health
of the machine based on the age-adjusted comparison.
Description
TECHNICAL FIELD
[0001] The present disclosure relates generally to a hydraulic
system and, more particularly, to a hydraulic system having a
diagnostic mode of operation.
BACKGROUND
[0002] Hydraulically operated machines, such as excavators,
loaders, dozers, motor graders, and other types of heavy equipment,
have multiple actuators (e.g., cylinders, motors, fans, brakes,
etc.) connected to move the machines. High-pressure fluid is
directed from one or more pumps on each machine to the actuators
via corresponding valves. Each of the pumps, actuators, valves, and
associated conduits and seals can wear over time and/or be damaged
by operation of the machine within its normal environment. When
these components wear or are damaged, operation of the machine
degrades, For example, the machines may operate with less power,
less speed, less range of motion, lower efficiency, less stability,
and/or less control when the hydraulic components are worn or
damaged. In addition, excessive wearing of one hydraulic component
(e.g., a pump) could result in catastrophic damage to the remaining
hydraulic components, if the wear is not addressed in a timely
manner. For this reason, it can be important to monitor a health of
the components and quickly address any component issues in order to
maintain the machines at a desired operating level.
[0003] Historically, hydraulic component health was monitored
manually during periodic or as-needed checks by a technician. In
particular, at a particular service interval or when malfunction of
a particular component was suspected, the technician would have
been called out to visit a particular machine. During the visit,
the technician. would connect one or more sensors to suspected
circuits of the machine, monitor parameters (e.g., pressure, speed,
range of motion, etc.) during particular movements of the machine,
and then compare the monitored parameters to threshold ranges or
values. If a significant deviation between the monitored and
threshold parameter values existed, it could be concluded that a
component was worn or damaged and was in need of repair.
[0004] Although perhaps acceptable in some situations, the
historical method of component health monitoring may also be
problematic. In particular, it may be difficult and time consuming
for the technician to know what sensors are appropriate to use in a
particular situation, and for the technician to properly connect
the sensors at the correct locations within the suspect circuit. In
addition, the technician may be required to know the appropriate
conditions under which parameter monitoring should be performed
(e.g., temperature, machine kinematics and positions, movement
speeds and loads, etc.), and to know the corresponding expected
performance ranges or threshold values. The technician may then be
required to perform comparison calculations and to judge a severity
of a resulting deviation, which can be subject to the technician's
training and experience, the machine's age and environment, and
other similar factors. Accordingly, the historical process may be
slow and expensive, and provide opportunity for error.
[0005] One attempt to address the issues discussed above is
disclosed in U.S. Pat. No. 7,204,138 (the '138 patent) by Du that
issued on Apr. 17, 2007. In particular, the '138 patent discloses a
health indicator for a hydraulic system having a pump, a sump, a
cylinder, and a valve connecting the cylinder to the pump and the
sump. The health indicator includes a pump discharge pressure
sensor, a swashplate angle sensor, a pump speed sensor, a head-end
pressure/position/speed sensor, a rod-end pressure/position/speed
sensor, and a controller. The controller is configured to compute,
based on signals received from the sensors in real time during
normal operation, an effective bulk modulus of the pump, aeration
of the hydraulic system, and/or a cavitation condition of the pump.
The controller is further configured to compare the effective bulk
module, aeration, and/or cavitation condition to predetermined
conditions stored within a health database. From this comparison,
the controller determines a relative operating health of the
hydraulic system. Based on the relative operating health of the
hydraulic system, maintenance operations and repairs can be made to
prevent catastrophic failure or before substantial deterioration of
the system can occur.
[0006] Although the health indicator of the '138 patent may be
helpful in determining when a pump malfunction exists, it may be
limited. In particular, the health indicator may do little to
determine when a non-pump malfunction exists. In addition, there
may be times when machine conditions are unfavorable for health
checking, and the health indicator of the '138 patent may be unable
to account for these times. Further, the health indicator may
provide only an indication as to proper or improper pump operation,
which may still require some subjective judgment from the
technician regarding how to address the operation.
[0007] The disclosed hydraulic system is directed to overcoming one
or more of the problems set forth above and/or other problems of
the prior art.
SUMMARY
[0008] One aspect of the present disclosure is directed to a
hydraulic system. The hydraulic system may include a fluid
actuator, a valve associated with the fluid actuator, at least one
sensor configured to generate a signal indicative of a performance
parameter of the hydraulic system, and a controller in
communication with the at least one sensor. The controller may be
configured to determine at least one of a diagnostic movement and a
diagnostic position of at least one of the fluid actuator and the
valve required to perform a health check of the hydraulic system,
and to correlate the signal generated only during completion of the
diagnostic movement or only when the at least one of the fluid
actuator and the valve are in the diagnostic position to a value of
the performance parameter. The controller may also be configured to
make a comparison of the value of the performance parameter to an
expected value, and to determine a health of the hydraulic system
based on the comparison.
[0009] Another aspect of the present disclosure is directed to a
method of determining a health of a hydraulic system having an
actuator and a valve associated with the actuator. The method may
include generating a signal indicative of a performance parameter
of the hydraulic system, and determining at least one of a
diagnostic movement and a diagnostic position of at least one of
the fluid actuator and the valve required for diagnosing the health
of the hydraulic system. The method may also include correlating
the signal generated only during completion of the diagnostic
movement or only when the at least one of the fluid actuator and
the valve are in the diagnostic position to a value of the
performance parameter. The method may further include making a
comparison of the value of the performance parameter to an expected
value, and determining the health of the hydraulic system based on
the comparison.
[0010] Yet another aspect of the present disclosure is directed to
a machine. The machine may include a frame, a power source mounted
to the frame, a linkage arrangement, and an actuator configured to
move the linkage arrangement. The machine may also include a pump,
a sump, and a valve disposed between the actuator, the pump, and
the sump. The machine may further include a plurality of sensors
configured to generate signals indicative of performance parameters
of the machine, and a controller in communication with the
plurality of sensors. The controller may be configured to receive
input indicative of a suspected hydraulic component malfunction,
and to determine at least one of a diagnostic movement and a
diagnostic position of at least one of the fluid actuator and the
valve required to perform a health check of the machine based on
the suspected hydraulic component malfunction. The controller may
also be configured to correlate the signals generated only during
completion of the diagnostic movement or only when the at least one
of the fluid actuator and the valve are in the diagnostic position
to values of the performance parameters. The controller may further
be configured to determine an age of the machine, to make an
age-adjusted comparison of the values of the performance parameters
to expected values, and to determine a health of the machine based
on the age-adjusted comparison.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a diagrammatic illustration of an exemplary
disclosed machine in a working environment;
[0012] FIG. 2 is a schematic illustration of an exemplary disclosed
hydraulic system associated with the machine of FIG. 1;
[0013] FIG. 3 is a schematic illustration of an exemplary disclosed
control valve that may be used in conjunction with the hydraulic
system of FIG. 2; and
[0014] FIGS. 4, 5, and 6 are flowcharts illustrating exemplary
disclosed processes that may be performed by the hydraulic system
of FIG. 2.
DETAILED DESCRIPTION
[0015] FIG. 1 illustrates an exemplary machine 10 having multiple
systems and components that cooperate to excavate and load earthen
material onto a nearby haul vehicle 12. In the depicted example,
machine 10 is a hydraulic excavator. It is contemplated, however,
that machine 10 could alternatively embody another type of
excavation or material handling machine, such as a backhoe, front
shovel, shovel, a motor grader, a dozer, or another similar
machine. Machine 10 may include, among other things, a linkage 14
configured to move a work tool 16 between a dig location 18 within
a trench or at a pile, and a dump location 20, for example over
haul vehicle 12 during a well-known truck loading cycle. Machine 10
may also include an operator station 22 for manual control of
linkage 14. It is contemplated that machine 10 may perform both
cyclical and non-cyclical operations, including cyclical operations
other than truck loading, if desired.
[0016] Linkage 14 may include a plurality of structural links that
are pinned to fluid actuators, which generate movements of work
tool 16. In the disclosed example, linkage 14 includes a boom 24
that is vertically pivoted relative to a machine frame 26 by one or
more boom cylinders 28 (only one shown in FIG. 1), and a stick 30
that is vertically pivoted relative to boom 24 by a stick cylinder
32. Linkage 14 further includes a bucket cylinder 34 that
operatively connects work tool 16 to a distal end of stick 30 for
use in racking and dumping (i.e., curling) work tool 16. Frame 26
may be pivotally connected to an undercarriage 36 by a swing motor
38, such that frame 26, linkage 14, and work tool 16 may be swung
together in a horizontal direction. It is contemplated that a
greater or lesser number of fluid actuators may be connected with
linkage 14 and/or connected in a manner other than described above,
if desired.
[0017] Operator station 22 may be configured to receive input from
an operator indicative of a desired work tool and/or machine
movement. Specifically, operator station 22 may include one or more
interface devices 40 located near an operator seat (not shown). In
one example, interface devices 40 are embodied as proportional-type
controllers configured to position and/or orient work tool 16 or
undercarriage 36 by producing position signals indicative of a
desired actuator speeds and/or forces in particular directions. The
position signals may be used to actuate any one or more of
cylinders 28, 32, 34 and/or swing motor 38.
[0018] It is contemplated that different interface devices 40 may
alternatively or additionally be included within operator station
22. These devices may include, for example, wheels, knobs,
push-pull devices, switches, pedals, touchscreen monitors, and
other devices known in the art. The devices may be used to
selectively activate a mode of operation (e.g., an autonomous
control mode), to initiate a function (e.g., a health checking
function), and/or to receive training (e.g., to receive
instructions and/or recommendations).
[0019] As illustrated in FIG. 2, machine 10 may include a hydraulic
system 42 having a plurality of fluid components that cooperate to
move work tool 16 (referring to FIG. 1) and machine 10. In
particular, hydraulic system 42 may include a first circuit 44
configured to receive a first stream of pressurized fluid from a
first source 46, and a second circuit 48 configured to receive a
second stream of pressurized fluid from a second source 50. First
circuit 44 may include a boom control valve 54, a bucket control
valve 56, and a left travel control valve 58 connected to receive
the first stream of pressurized fluid in parallel. Second circuit
48 may include a right travel control valve 60, a stick control
valve 62, and a swing control valve 63 connected in parallel to
receive the second stream of pressurized fluid. It is contemplated
that additional control valve mechanisms may be included within
first and/or second circuits 44, 48 such as, for example, one or
more attachment control valves and other suitable control valve
mechanisms.
[0020] The control valves of first and second circuits 44, 48 may
be connected to allow pressurized fluid to flow to and drain from
their respective actuators via common passageways. Specifically,
the control valves of first circuit 44 may be connected to first
source 46 by way of a first common supply passageway 66, and to a
tank 64 by way of a first common drain passageway 68. The control
valves of second circuit 48 may be connected to second source 50 by
way of a second common supply passageway 70, and to tank 64 by way
of a second common drain passageway 72.
[0021] Because the elements of boom, bucket, left travel, right
travel, stick, and swing control valves 54, 56, 58, 60, 62, 63 may
be similar and function in a related manner, only the operation of
bucket control valve 56 will be discussed in this disclosure. As
shown in FIG. 3, bucket control valve 56 may include a first
chamber supply element 56A, a first chamber drain element 56C, a
second chamber supply element 56B, and a second chamber drain
element 56D. First and second chamber supply elements 56A, 56B may
be connected in parallel with fluid passageway 66 to fill their
respective chambers with fluid from first source 46, while first
and second chamber drain elements 56C, 56D may be connected in
parallel with fluid passageway 68 to drain the respective chambers
of fluid.
[0022] To retract bucket cylinder 34, first chamber supply element
56A may be moved to allow the pressurized fluid from first source
46 to fill the first chamber of bucket cylinder 34 with pressurized
fluid via fluid passageway 66, while second chamber drain element
56D may be moved to drain fluid from the second chamber of bucket
cylinder 34 to tank 64 via fluid passageway 68. To extend bucket
cylinder 34, second chamber supply element 56B may be moved to fill
the second chamber of bucket cylinder 34 with pressurized fluid,
while first chamber drain element 56C may be moved to drain fluid
from the first chamber of bucket cylinder 34. In some instances, it
may also be possible to pass pressurized fluid directly from
passage 66 to passage 68 via control valve 54, if desired (e.g.,
from 56A to 56C or from 56B to 56D), such that no movement of
bucket cylinder 34 is realized. This may be done, for example,
during a diagnostic routine. it is contemplated that both the
supply and drain functions may alternatively be performed by a
single element associated with the first chamber and a single
element associated with the second chamber, or by a single valve
that controls all filling and draining functions.
[0023] Returning to FIG. 2, the common supply and drain passageways
of first and second circuits 44, 48 may be interconnected for
makeup and relief functions. In particular, first and second common
supply passageways 66, 70 may receive makeup fluid from tank 64 by
way of first and second bypass elements 74, 76, respectively fluid
within first or second circuits 44, 48 exceeds a predetermined
pressure level, fluid from the circuit having the excessive
pressure may drain to tank 64 by way of a shuttle valve 78 and a
common main relief element 80. Other arrangements of bypass and
relief valves may be used, as is known in the art.
[0024] A straight travel valve 82 may selectively rearrange left
and right travel control valves 58, 60 into a parallel relationship
with each other. In particular, straight travel valve 82 may
include elements movable from a first position at which left and
right travel control valves 58, 60 are independently supplied with
pressurized fluid, to a second position at which left and right
travel control valves 58, 60 are interconnected for dependent
movement. The dependent movement of left and right travel motors
65L, 65R may function to provide substantially equal rotational
speeds of left and right tracks 40L, 40R, thereby propelling
machine 10 in a straight direction.
[0025] A combiner valve 84 may be used to selectively combine the
first and second streams of pressurized fluid from first and second
common supply passageways 66, 70 for high speed movement of one or
more fluid actuators. In particular, when a particular combination
of functions associated with a particular circuit requires a rate
of fluid flow greater than an output capacity of the associated
single fluid source, fluid from the other circuit may be diverted
to supply the required extra flow.
[0026] In one embodiment, hydraulic system 42 may include a warm-up
circuit. That is, the common supply and drain passageways 66, 68
and 70, 72 of first and second circuits 44, 48, respectively, may
be selectively communicated via first and second bypass passageways
86, 88 for warm-up and/or other bypass functions. A bypass valve 90
may be located in each of bypass passageways 86, 88 and configured
to direct fluid from common supply passageways 66 and 70 to common
drain passageways 68 and 72, respectively. It is contemplated that
bypass passageways 86, 88 and bypass valves 90 may be omitted, if
desired.
[0027] Hydraulic system 42 may also include a controller 92 in
communication with operator interface device 40, first and/or
second sources 46, 50, the supply and drain elements of control
valves 54-62, combiner valve 84, and bypass valves 90. It is
contemplated that controller 92 may also be in communication with
other components of hydraulic system 42 such as, for example, first
and second bypass elements 74, 76, common main relief element 80,
straight travel valve 82, and other such components of hydraulic
system 42. Controller 92 may embody a single microcontroller or
multiple microcontrollers that include a means for controlling an
operation of hydraulic system 42. Numerous commercially available
microcontrollers can be configured to perform the functions of
controller 92. It should be appreciated that controller 92 could
readily be embodied in a general machine microcontroller capable of
controlling numerous machine functions. Controller 92 may include a
memory, a secondary storage device, a controller, and any other
components for running an application. Various other circuits may
be associated with controller 92 such as power supply circuitry,
signal conditioning circuitry, solenoid driver circuitry, and other
types of circuitry.
[0028] One or more maps relating the interface device position
signal, actuator velocity, associated flow rates and pressures,
and/or valve element and actuator positions may be stored in the
memory of controller 92. Each of these maps may include a
collection of data in the form of tables, graphs, and/or equations.
Controller 92 may be configured to allow the operator to directly
modify these maps and/or to select specific maps from available
relationship maps stored in the memory of controller 92 to affect
fluid actuator motion. It is contemplated that the maps may
additionally or alternatively be automatically selectable based on
active modes of machine operation.
[0029] In some embodiments, the maps stored in the memory of
controller 92 may be modified or adjusted by controller 92 based on
an age and/or condition of machine 10 and hydraulic system 42. That
is, as machine 10 and hydraulic system 42 age, the relationships
between pressures, velocities, flow rates, positions, and cycle
times may change naturally due to expected wear of system
components. If unaccounted for, the same combination of commands
that initially resulted in a desired pressure, velocity, flow rate,
position, cycle time, etc., may instead result in something
unexpected and/or undesired. Accordingly, controller 92 may be
configured to selectively adjust the values stored in the maps by
amounts relating to the age of machine 10 and/or hydraulic system
42.
[0030] Controller 92 may be configured to receive input from
operator interface device 40 and to command operation of control
valves 54, 56, 58, 60, 62, 63 in response to the input and the
relationship maps described above. Specifically, controller 92 may
receive an interface device position signal indicative of a desired
velocity of a particular actuator, and reference the selected
and/or modified relationship maps stored in the memory of
controller 92 to determine operating parameters for each of the
corresponding supply and drain elements within control valves 54,
56, 58, 60, 62, 63. The operating conditions may then be commanded
of the appropriate supply and drain elements to cause filling of
the first or second chambers at a rate that results in the desired
work tool movement, position, velocity, and/or force.
[0031] When a malfunction of a particular hydraulic system
component occurs, fluid flow through hydraulic system 42 may be
disrupted, This disruption may be manifest in a number of ways. For
instance, one or more actuators and/or valves may move at a speed
and/or with a force different than desired or move discontinuously.
Resulting pressures, pressure differentials, flow rates, etc. may
be lower or higher than normal. Desired positions of the valves
and/or actuators may not be achieved. Other unexpected results may
also occur. Accordingly, it can be important for the health of
hydraulic system 42 to be periodically checked, such that
performance of machine 10 may be continuous and reliable.
Controller 92 may facilitate these checks by implementing one or
more different diagnostic routines, as will be described in more
detail below.
[0032] In some embodiments, controller 92 may communicate with the
operator of machine 10 (e.g., via interface devices 40) to instruct
the operator to manually cause movements and/or velocities of
particular hydraulic system components that are conducive to the
diagnostic routines performed by controller 92 during the health
check of hydraulic system 42. For example, during the health check
of system 42, controller 92 may be configured to reference one or
more of the maps stored in the memory of controller 92 to determine
particular positions and/or velocities that should be implemented
during a particular one of the diagnostic routines. Controller 92
may then cause corresponding instructions to be shown on a display
inside operator station 22, allowing the operator to manually
implement the diagnostic positions and/or velocities. Controller 92
may also be configured, in other embodiments, to autonomously cause
the particular diagnostic movements and velocities to be
implemented, if desired. In yet other embodiments, controller 92
may simply be configured to recognize when the particular
diagnostic movements and velocities are occurring naturally during
normal operations of machine 10, and then responsively implement
the associated diagnostic routines. These processes will be
discussed in more detail in the following section, with reference
to FIGS. 4-6.
[0033] Controller 92 may be configured to monitor the performance
of hydraulic system 42 during completion of the diagnostic
routines, for example by way of one or more sensors 94. These
performance parameters may include, among other things, a time
required to complete a particular known cycle (e.g., the truck
loading cycle), a position and/or speed of a particular control
valve or actuator, a pressure and/or pressure differential at a
particular location within system 42, a pump displacement setting,
an engine speed, etc. Controller 92 may then compare the monitored
performance to age-adjusted expected values or ranges for the same
parameters to determine if particular components of hydraulic
system 42 are functioning properly.
[0034] In the disclosed embodiments of FIGS. 2 and 3, multiple
pressure-type sensors 94 are shown. In particular, a first pressure
sensor 94 is located to sense a pressure of common supply passage
66 (e.g., an outlet pressure of first source 46), while a second
pressure sensor 94 is located to sense a pressure of common drain
passage 68. In this manner, controller 92 may be able to calculate
a pressure differential across any one or more of hydraulic
cylinders 28, 32 and left travel motor 65L (depending on which
actuator is being used at the time of signal generation) based on
signals from the first and second pressure sensors 94. Similarly, a
third pressure sensor 94 is located to sense a pressure of common
supply passage 70 (e.g., an outlet pressure of second source 50),
while a fourth pressure sensor 94 is located to sense a pressure of
common drain passage 72. In this manner, controller 92 may be able
to calculate a pressure differential across any one or more of
right travel motor 65R, hydraulic cylinder 34, or swing motor 38
based on signals from the first and second pressure sensors 94.
Likewise, one or more pressure sensors 94 may be associated with
some or all of control valves 54, 56, 58, 60, 62, 63 (see FIG. 3)
or any other valve (e.g., bypass valves 74, 76, main relief valve
80, straight travel valve 82, combiner valve 84, etc.) for similar
purposes. It is contemplated that any number of sensors of any type
may be utilized and/or placed at different locations within
hydraulic system 42, as desired.
[0035] FIGS. 4-6 are flowcharts depicting exemplary diagnostic
operations of hydraulic system 42. FIGS. 4-6 will be discussed in
more detail in the following section to further clarify the
disclosed concepts.
INDUSTRIAL APPLICABILITY
[0036] The disclosed hydraulic system may be applicable to any
machine having fluid components. The disclosed hydraulic system may
help to maintain desired operation of the machine through
implementation of health checks of the components. The disclosed
hydraulic system may also help to diagnose a problem with the
components via one or more different diagnostic routines (e.g., a
manually triggered routine, an automatically triggered routine, and
a continuously operating routine). These routines will now be
described in detail with reference to FIGS. 4-6.
[0037] The manually triggered routine is shown in FIG. 4. As shown
in this figure, the first step of the diagnostic routine may be for
controller 92 to receive input from the operator of machine 10 that
is indicative of a desire to start a diagnostic check of hydraulic
system 42 (Step 400). This input may be generated via manipulation
of interface device 40. For example, the operator of machine 10 may
manipulate interface device 40 at the start of a shift, at the end
of a shift, during a normal maintenance process, when a problem
with hydraulic system 42 is suspected, or at any other convenient
time.
[0038] Once the input from the operator is received, controller 92
may determine if the current operating parameters of machine 10 are
within ranges necessary for accurate diagnostic testing to begin
(Step 405). In particular, in some embodiments, controller 92 may
be able to accurately check the health of machine 10 only when
particular circumstances are present. These circumstances can be
associated with, among other things, a particular position,
orientation, or movement of a particular valve or actuator; a
particular pattern or sequence of movements (e.g., completion of a
cycle such as the truck loading cycle), a particular speed of
movement; movement under a particular load; movement when hydraulic
temperatures and/or pressures are at certain levels; etc. In some
embodiments, health checks of different hydraulic system components
may require different circumstances to be present, in other
embodiments, a circuit-level health check may require the
circumstances to change in a particular order and at particular
timings, as controller 92 sequentially checks each component within
a particular circuit.
[0039] Accordingly, depending on the type of diagnostic check that
has been requested by the operator, controller 92 may be configured
to reference the type of diagnostic check with the maps stored in
memory to determine a corresponding circumstance or set of
circumstances that should be present during the diagnostic check to
produce accurate results. Controller 92 may then instruct the
operator of machine 10 to change machine operating parameters to
provide the correct set of circumstances (Step 410). For example,
controller 92 may cause to he displayed within operator station 22
images, written instructions, and/or verbal instructions telling
the operator to raise boom 24 (referring to FIG. 1) to a particular
height, at a particular speed, with a particular load, or within a
particular period of time; to complete a truck loading cycle; to
rack work tool 16; to swing frame 26, etc. In some instances, the
instructions may pertain to the simultaneous use of multiple valves
and/or actuators. In other instances, however, the instructions may
pertain to the independent use of a single valve and/or actuator.
By using only a single valve and/or actuator at a time during
diagnostic checking, a number of factors influencing hydraulic
system performance may be reduced, and the remaining factors may be
associated with only the particular valve or actuator being used.
In this way, a component or circuit suspected of malfunctioning or
failing may be independently tested.
[0040] During and/or after operator-caused movements of machine 10
that produce the circumstances required the operator-requested
diagnostic check, controller 92 may sense the performance of
machine 10 (Step 415). For example, while work tool 16 is being
lifted to a particular height (or lifted at a particular velocity,
under a particular load, during completion of a particular cycle,
etc.) controller 92 may monitor signals (e.g., pressure or pressure
differential signals) produced by one or more sensors 94 associated
with one or more of the hydraulic system components (e.g, boom
control valve 54, boom cylinders 28, first source 46, etc.) being
used to do the lifting.
[0041] After completion of step 415, controller 92 may be further
configured to compare the values of the signals sensed during step
415 to corresponding expected values or ranges to determine if the
values are within acceptable tolerances of the expected performance
values or ranges (Step 420). For example, controller 92 may compare
the pressure differential monitored when lifting work tool 16
during completion of step 415 to an expected pressure differential
value or range. The expected performance value and/or range may be
stored within the memory of controller 92 for this purpose.
[0042] When the comparison made by controller 92 at step 420 shows
that the monitored performance of machine 10 is not within an
acceptable tolerance of the expected performance value or range,
controller 92 may determine a deviation level associated with the
results of the comparison (Step 425). In one example, controller 92
is configured to classify a deviation determined at step 420 as a
Level I deviation, a Level II deviation, or a Level III deviation.
In this example, a Level III deviation may be the most severe
deviation possible and often corresponds with a significant failure
of hydraulic system 42. In response to a deviation being classified
as Level III, controller 92 may instruct the operator to
immediately shut down machine 10 in order to prevent further damage
of hydraulic system components (Step 430). Controller 92 may
provide additional information to the operator regarding the
failure, along with recommendations about what repairs should be
performed.
[0043] A Level II deviation may be less severe than a Level III
deviation, but still could result in costly damage to or downtime
of machine 10 if not corrected in a timely manner. Accordingly, in
response to a deviation being classified as Level II, controller 92
may instruct the operator to complete the current work shift
(operation, task, etc.) and then, at a convenient time, to move
machine 10 to a repair facility for service to be performed (Step
435). This may allow for the service to be performed at a time when
the production of machine 10 will not be significantly impacted,
and machine 10 may not be left stranded at a location inconvenient
for the repairs to be made. As with a Level III deviation,
controller 92 may provide additional information regarding the
cause of the Level II deviation, along with recommendations about
what repairs should be performed.
[0044] A Level I deviation may be less severe than a Level II
deviation, but still have a long-term effect on the operating cost
and/or profitability of machine 10, if not corrected. Accordingly,
in response to a deviation being classified as Level I, controller
92 may recommend to the operator that a specific repair be
performed at a next scheduled service interval (Step 440).
[0045] Returning to step 420, when machine 10 performs as expected
(step 420:Y) and passes the diagnostic health check, controller 92
may complete the process without flagging any kind of failure or
repair error (Step 445). This result may be reported to the
operator of machine 10, and control may return to step 400.
[0046] The automatically triggered routine is shown in FIG. 5. As
shown in this figure, the first step of the diagnostic routine may
be for controller 92 to receive input that is indicative of a
possible malfunction of hydraulic system 42 (Step 500). This input
may be generated any time the value of a monitored performance
parameter falls outside of an expected range. For example, when a
temperature, pressure, cycle time, etc. generated by one or more
sensors 94 is too high, too low, or outside of an expected range
for an extended period of time, it may be possible for a failure to
be the cause. In this situation, controller 92 may be automatically
triggered to start a diagnostic routine in order to determine the
source of the failure.
[0047] Once controller 92 is triggered to initiate a diagnostic
routine, controller 92 may determine what diagnostic checks are
associated with the possible malfunction (Step 505). In particular,
controller 92 may be capable of performing may different diagnostic
checks; each associated with a different component and/or circuit.
Rather than performing all of the diagnostic checks in response to
any sensed abnormality, controller 92 may instead narrow down the
different diagnostic checks to a subset of checks associated with
the particular component or circuit that is suspected of
malfunctioning. In this way, a time and cost of the diagnostic
checking may be reduced. Controller 92 may reference the abnormal
value(s) used as triggers for step 500 with the maps stored in
memory to determine the corresponding set of diagnostic checks.
[0048] As described above, controller 92 may then determine if the
current operating parameters of machine 10 are within accuracy
ranges necessary for testing of the subset of diagnostic checks to
begin (Step 510). In particular, in some embodiments, controller 92
may be able to accurately check the health of machine 10 only when
particular circumstances are present. These circumstances can be
associated with, among other things, a particular position,
orientation, or movement of a particular valve or actuator; a
particular pattern or sequence of movements (e.g., completion of a
cycle such as the truck loading cycle), a particular speed of
movement; movement under a particular load; movement When hydraulic
temperatures and/or pressures are at certain levels; etc. In some
embodiments, health checks of different hydraulic system components
may require different circumstances to be present. In other
embodiments, a circuit-level health check may require the
circumstances to change in a particular order and at particular
timings, as controller 92 sequentially checks each component within
a particular circuit.
[0049] Accordingly, depending on the type of diagnostic check that
will be performed, controller 92 may be configured to reference the
type of diagnostic check with the maps stored in memory to
determine a corresponding circumstance or set of circumstances that
should be present during the diagnostic check to produce accurate
results. And when the current machine parameters do not match the
parameters required for diagnostic testing, controller 92 may
automatically make changes to machine operating parameters to
provide the correct set of circumstances (Step 515). For example,
controller 92 may automatically raise boom 24 (referring to FIG. 1)
to a particular height, at a particular speed, with a particular
load, or within a particular period of time; to complete a truck
loading cycle; to rack work tool 16; to swing frame 26, etc. in
some instances, the movements may be simultaneously commanded of
multiple valves and/or actuators. In other instances, however, the
movements may he commanded of a single valve and/or actuator.
[0050] During and/or after the autonomous movements of machine 10
that produce the circumstances required for the subset of
diagnostic checks, controller 92 may sense the performance of
machine 10 (Step 520). For example, while controller 92 is causing
work tool 16 to be lifted to a particular height (or lifted at a
particular velocity, under a particular load, during completion of
a particular cycle, etc.,) controller 92 may monitor signals (e.g.,
pressure or pressure differential signals) produced by one or more
sensors 94 associated with one or more of the hydraulic system
components (e.g., boom control valve 54, boom cylinders 28, first
source 46, etc.) being used to do the lifting.
[0051] After completion of step 520, controller 92 may be further
configured to compare the values of the signals sensed during step
520 to corresponding expected values or ranges to determine if the
values are within acceptable tolerances of the expected performance
values or ranges (Step 525). For example, controller 92 may compare
the pressure differential monitored when lifting work tool 16
during completion of step 520 to an expected pressure differential
value or range. The expected performance value and/or range may be
stored within the memory of controller 92 for this purpose.
[0052] When the comparison made by controller 92 at step 525 shows
that the monitored performance of machine 10 is not within an
acceptable tolerance of the expected performance value or range,
controller 92 may determine a deviation level associated with the
results of the comparison (Step 530). As described above with
respect to the manual mode of operation, controller 92 may also be
configured to classify a deviation determined at step 525 during
operation in the automatic mode as the Level I deviation, the Level
II deviation, or the Level III deviation. In response to a
deviation being classified as Level III, controller 92 may
automatically shut down machine 10 in a safe and controlled manner
in order to prevent further damage of hydraulic system components
(Step 535). Controller 92 may then communicate (e.g., to an onboard
operator or to a remote back office) additional information
regarding the failure, along with recommendations about what
repairs should be performed.
[0053] In response to a deviation being classified as Level II,
controller 92 may autonomously move machine 10 to a repair facility
for service to be performed at completion of the current work shift
(operation, task, etc.) (Step 540). This may allow for the service
to he performed at a time when the production of machine 10 will
not be significantly impacted, and machine 10 may not be left
stranded at a location inconvenient for the repairs to be
performed. As with a Level III deviation, controller 92 may provide
additional information regarding the cause of the Level II
deviation, along with recommendations about what repairs should be
performed.
[0054] In response to a deviation being classified as Level I,
controller 92 may automatically schedule a specific repair to be
completed at a next scheduled service interval (Step 545).
[0055] Returning to step 525, when machine 10 performs as expected
(step 525:Y) and passes the diagnostic health check, controller 92
may complete the process without flagging any kind of failure or
repair error (Step 550).
[0056] The continuous mode of operation shown in FIG. 6 may not
require a specific trigger in order to initiate diagnostic testing,
other than machine 10 being turned on (Step 600). In particular,
any time that machine 10 is operational, controller 92 may be
continuously determining if the current operating parameters of
machine 10 are within accuracy ranges necessary for completing any
one of a plurality of diagnostic tests that controller 92 is
capable of performing (Step 605). As described above, in some
embodiments, controller 92 may be able to accurately perform
certain diagnostic checks only when particular circumstances are
present. Accordingly, depending on the current conditions,
controller 92 may begin a particular diagnostic check and start
sensing corresponding performance parameters any time that the
associated circumstances are present (Step 610). For example, any
time that boom 24 is being lifted at a particular speed, with a
particular load, to a particular height, etc., without any
simultaneous tilting, racking, or swinging, controller 92 may be
configured to initiate a diagnostic check of boom control valve 54
and/or boom cylinders 28. Controller 92 may then complete steps
615-640, which may be substantially identical to steps 420 445
already described above.
[0057] Several benefits may be associated with the disclosed
hydraulic system. For example, the disclosed hydraulic system may
be configured to diagnose malfunctions associated with any
hydraulic system component, including pump and non-pump components.
In addition, a high degree of accuracy may be obtained during
diagnostic checks, as initiation of the diagnostic checks may be
based on current operating conditions being favorable for the
checks. Further, the disclosed hydraulic system may provide not
only an indication of a source of a system failure, but may also
provide instructions on how to respond to the failure.
[0058] It will be apparent to those skilled in the art that various
modifications and variations can be made to the disclosed hydraulic
system. Other embodiments will be apparent to those skilled in the
art from consideration of the specification and practice of the
disclosed hydraulic system. It is intended that the specification
and examples be considered as exemplary only, with a true scope
being indicated by the following claims and their equivalents.
* * * * *