U.S. patent application number 10/226979 was filed with the patent office on 2004-02-26 for electronic fingerprints for machine control and production machines.
Invention is credited to Kiesel, Martin, Mutscheller, Wolfgang.
Application Number | 20040039478 10/226979 |
Document ID | / |
Family ID | 31887369 |
Filed Date | 2004-02-26 |
United States Patent
Application |
20040039478 |
Kind Code |
A1 |
Kiesel, Martin ; et
al. |
February 26, 2004 |
Electronic fingerprints for machine control and production
machines
Abstract
An electronic fingerprint measures a state of a machine and/or
process. A controller controls movements of at least one component
of the machine and a fingerprint device selects, for measurement,
certain movements of the machine for generating an electronic
fingerprint that that is representative of a condition of the
machine tool or process.
Inventors: |
Kiesel, Martin; (Poxdorf,
DE) ; Mutscheller, Wolfgang; (Stuttgart, DE) |
Correspondence
Address: |
WHITE & CASE LLP
PATENT DEPARTMENT
1155 AVENUE OF THE AMERICAS
NEW YORK
NY
10036
US
|
Family ID: |
31887369 |
Appl. No.: |
10/226979 |
Filed: |
August 23, 2002 |
Current U.S.
Class: |
700/174 |
Current CPC
Class: |
G05B 2219/50197
20130101; Y02P 90/80 20151101; G05B 2219/34282 20130101; G05B
19/406 20130101; G05B 19/042 20130101; Y02P 90/86 20151101; G05B
2219/31422 20130101 |
Class at
Publication: |
700/174 |
International
Class: |
G06F 019/00 |
Claims
In the claims:
1. A electronic fingerprint apparatus for measuring a state of a
machine and/or process, comprising: an automation component
comprising a controller for controlling movements of at least one
component of the machine or a portion of the process, wherein the
automation component provides means for capturing electronic
fingerprints representative of the state of the machine and/or
process; and a fingerprint device for selecting, for measurement,
certain movements of the machine for generating an electronic
fingerprint that that is representative of a condition of the
machine tool
2. The apparatus of claim 1, wherein the automation component is a
numeric control, a motion controller, a programmable logic
controller or an intelligent drive.
3. The apparatus of claim 1, wherein the automation component and
the corresponding Engineering System provide a program
platform/environment for the implementation of electronic
fingerprints by an application engineer.
4. The apparatus of claim 1, wherein applicative implementation of
the fingerprints is done by a configuration process in the
engineering system and/or a programming process using a specific
API for the implementation of fingerprints.
5. The apparatus of claim 1, wherein the start of capturing the
fingeprints is done by one of the following actions selected from
the group consisting of starting by local user via local HMI and
starting by remote user via Ethernet/Internet and starting based on
an event evaluated in an application program running in the
automation component.
6. The apparatus of claim 1, wherein the apparatus is used for one
of the following machines selected from the group consisting of a
machine tool and a packaging machine and a rubber and plastics
machine and a presses and printing machine and a wood machine and a
glass machine and a ceramic machine and a stone machine and a
textile machine and a robotics and a handling machine.
7. The apparatus of claim 1, wherein the fingerprint device and the
automation component generate an electronic fingerprint that is
generic to a type of machine tool that indicates a stable behavior
of the machine tool.
8. The apparatus of claim 2, wherein the fingerprint device and the
automation component generates an electronic fingerprint having a
deviation from the stable behavior, thereby indicating an unstable
behavior of the machine.
9. The apparatus of claim 1, wherein the fingerprint device and the
automation component generates a specific fingerprint of a
particular production machine that is representative of a state of
an output of the particular production machine and/or the stable
behavior of the machine.
10. The apparatus of claim 1, further comprising a graphical user
interface for displaying a graphical depiction of the electronic
fingerprint.
11. The apparatus of claim 1, wherein the fingerprint device has a
capability of generating a periodic electronic fingerprint that is
developed from a snap shot of the state of the machine at a certain
time.
12. The apparatus of claim 6, further comprising an application for
comparing the electronic fingerprints over time.
13. The apparatus of claim 6, further comprising a memory for
storing the electronic fingerprints as a database.
14. The apparatus of claim 1, further comprising a maintenance
scheduler for scheduling maintenance of the machine based on a
prediction of a failure of the machine based on the electronic
fingerprint.
15. The apparatus of claim 1, further comprising a remote
communication capability that couples the machine to a remote
processor.
16. The apparatus of claim 10, wherein the electronic fingerprint
is downloaded over the remote communication to the remote
processor.
17. A method for generating electronic fingerprints for measuring a
state of a machine and/or process, comprising the steps of:
selecting parameters of at least one-component of the machine, for
measurement, that is representative of a condition of the machine;
reading the parameters; and storing the read parameters, thereby
creating an electronic fingerprint of the machine representative of
the condition of the machine.
18. The method of claim 17, wherein the step of selecting selects
parameters that at a time when the machine is in a stable state to
generate thereby a generic type of electronic fingerprint that
indicates a stable behavior.
19. The method of claim 18, wherein the step of selecting selects
parameters having a deviation from the stable behavior, thereby
generating an electronic fingerprint indicating an unstable
behavior of the machine.
20. The method of claim 17, wherein the step of selecting selects
parameters from a particular production machine that is
representative of a state of an output of the particular production
machine.
21. The method of claim 17, further comprising the step of
generating a graphical depiction of the electronic fingerprint.
22. The method of claim 17, further comprising the step of
comparing the electronic fingerprints over time.
23. The method of claim 17, further comprising the step of
scheduling maintenance based on the electronic fingerprint.
24. The method of claim 17, further comprising the step of remotely
coupling the machine to a remote processor.
25. A computer readable product having encoded therein instructions
for driving a computer processor according to the steps of claim
17.
Description
BACKGROUND
[0001] Trace functionality in a drive or in automation system and
trace selectable feedback or fixed parameters or process values,
and all control parameters to control the process is traceable. For
example, it is normal the practice today to employ trace
functionality to control currents or motor currents. While trace
functionality is used to set up the machine, it is not being used
to develop ideas to implement or bring about new features in drive
control, motion control or numeric control. It is not being used to
describe the characteristics of the machine and use these
characteristics to improve the quality of the process or
product.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0002] Within the meaning of the present specification, electronic
fingerprints for a machine (eg. Machine tool or production machine)
are a set of measurements in a machine that are characteristic of
and document the behavior of the machine. In machine control and
production machines, every machine has variations in its behavior
that make it unique. These unique behavioral traits are even
diverse as even between machines of the same type and character.
That is, they could even be the same model of machine. No matter
how similar two machines are they will always have some unique
behavior that can be isolated and documented to identify a
condition of the particular machine. This is more true over time,
where operation of the machine may, and indeed does, alter the
working components of the machine or the alignment or the position
of its components, therefore, changing the behavioral
characteristics of the machine. The set of behavioral
characteristics that uniquely identify a particular machine are
herein referred to as electronic fingerprints.
[0003] The present invention determines, for any particular
machine, those set of characteristics that uniquely identify the
condition of that machine. The novelty in the present invention is
not only the fingerprints, but also the skill in knowing which
measurements will result in capturing the unique characteristics
and which measurements to make. That is, the measurements
characterize the individual characteristic of the machine. Further,
it is optimum to identify the minimum set of behavioral
characteristics that identifies the particular machine. In
addition, the electronic fingerprints of the present invention are
derived, such that, no matter how the fingerprint evolves over
time, a fixed fingerprint system is developed so that the machine
condition can be identified over time.
[0004] There are several advantages to employing electronic
fingerprints. For one thing, it allows the operator to check the
instantaneous condition of the machine. Further, the changes of the
behavior of a machine can be compared to an initial state to a
later state by certain measurements in the machine. The deviation
compared to the original state of the machine could be telling of
the machines performance. The measurements may be repeated
periodically to measure the behavior of machines. This could also
be used for predictive maintenance by using the fingerprint to
indicate a machine condition.
[0005] Now with reference to FIG. 1, the present invention provides
an automation component 10 that makes available mechanisms to
determine electronic fingerprints. The automation component may be,
for example part of a machine tool or a production machine.
Generally, there is provided a controller (eg. PLC) for logic
control 12a and the mechanical part that is driven by the
controller (motion control or numeric control)12b. As an
alternative one controller could do both jobs (logic and motion
control). There is further provided a user interface 16a that
provides the user with an interface for monitor and control of the
automation component 10.
[0006] A separate user interface 16b provides a user interface with
an engineering system (setup, configuration, programming) for the
automation component. The user interfaces 16a and 16b might be
running on one HW-platform. In addition, remote access to, for
example, a remote PC 18 through a communication channel 20, such as
the Internet or Intranet, provided by an appropriate interface,
TCP/IP or Ethernet, etc. An analysis 22 of the machine can be
derived and displayed at the remote PC, for example. A machine data
server (14) is linked to the automation component. The present
invention specifically provides means for identifying the state of
the machine and/or product, and a condition thereof, by a
fingerprint of the machine at a given time. The automation
components provide means for capturing fingerprints of the
machine.
[0007] There are, of course, provided additional input/output
signals depending on the type of machine controlled. Here, for
example, there is provided an input/output rack for inputting and
outputting signals 24, such as those found on a programmable
logical controller (PLC). There is also provided an axis mechanism
26 which controls an axis of a movable piece of the machinery, such
as robotic arm, drill press, etc. The machine may also be coupled
to other processors, such as in a communication network 28.
[0008] In order to obtain and analyze the fingerprints, the present
invention provides a graphical user interface (GUI) 18. This may
be, for example, a human machine interface (HMI) that is modified
according to the present invention to lift, store and examine the
fingerprints. The interface could be provided, for example, on a
host PC and connected to the automation component by a
communication interface, such as, for example the Ethernet or
Internet. With the interface provided, the fingerprints can be
evaluated manually or automatically according to the particular
description thereof set forth below.
[0009] As already indicated, part of the novelty of the invention
is in knowing which measurements to make that will reveal the
electronic fingerprint. The technique may vary according to type of
machine. For example, machine tools having a cutting function can
be caused to undergo a test trace function. However, other
machines, such as a pump have no trace capability. The invention
includes various techniques, dependent on the type of machine, to
develop, or "lift", the electronic fingerprint. The recognition of
the finger prints is realizable using various techniques.
[0010] Fingerprint functionality can be implemented in the system
software of the automation component 10. As already mentioned,
electronic fingerprints can be realized concretely using an
application of, for example, a trace test, for machine tools having
a trace functionality with a numerical control. In another aspect,
there is provided in the automation component an easily
programmable expiration operational sequence. Using such
application programs, the fingerprints can be lifted. The
automation component places suitable Application Program Interfaces
(API) over from an application program to finger prints to take
up.
[0011] If the condition of the machine is the fingerprint and they
are lifted using programming applications, the programming signals
can be thought of as the "dust" with which the fingerprints are
formed. These signals may be, for example, internally accessible
signals, which are suitable, to document the quality of an
expiration or a process. Thereby, the process specific parameters
are defined. Also, any of the measured values of drives, parameters
from motion controllers, production machines or format data from
the application program may be utilized.
[0012] In one example, the signal may be measured from
distinguished, event-controlled signals that are generated
cyclically or during a certain period. For another, the measured
signals are derived from the control and/or by control/application
via auxiliary sensor technology. If necessary, the auxiliary sensor
technology could include, for example, acceleration meters.
[0013] As shown in FIG. 2a, the electronic fingerprint 30 of the
present invention can be visualized as a two print. As shown by the
parameter points 32, whose value is indicated by the position in
the matrix 34, connected by the dashed lines 36. In this manner, it
can be readily seen that the electronic fingerprint of the present
invention is similar to an actual fingerprint in the sense that it
maps out an imprint that is characteristic of the machine from
which the electronic fingerprint is lifted. Of course, the
fingerprint shown in FIG. 2a is an oversimplification, and can be
expressed as a complex array of parameter points and may be an
n-dimensional fingerprint displayed as a computer graphic.
[0014] As will be appreciated from FIG. 2. The condition of the
machine can be determined from the fingerprint. In FIG. 2b, for
example, there is shown a fingerprint that is unhealthy. Notice the
deviation 38, illustrated by the arrow, which indicates a variance
from the healthy fingerprint of FIG. 2a. The variance 40 can be
thought of as the area underneath the portion of the fingerprint
lying outside the healthy fingerprint. The fingerprints can be
stored in advance in a database and later compared. Also, unhealthy
fingerprints can be collected over time to form a database for
future reference in other applications. With the electronic
fingerprints of the present invention, it will be instantly
recognized that it is advantageous to analyze machines in this
manner because of the relevant ease in which deviations are
identified. This is particularly useful for user visual inspection
of the fingerprints. In a glance, they can determine whether the
machine is in an error condition or not.
[0015] The fingerprint may be representative of a plurality of
machine related states, including a machine behavior, for example.
The fingerprint may also be representative or product quality,
which depends on both the machine and the material. In the example
of FIGS. 2a and 2b, the fingerprint may indicate, in a laser
cutting machine, the special relationship between speed of movement
of laser and power. If, for example, the relationship is not
maintained at the correct fingerprint (FIG. 2b) the laser will move
too slowly and burn holes in the workpiece. On the other hand, the
laser may move too quickly and wont cut the material. When the
process is stable, as in FIG. 2a, then the product quality can be
determined, i.e., the workpiece is cut properly by the laser in our
example.
[0016] As with any fingerprint, the electronic fingerprint is
developed for analysis, a sort of electronic sleuthing. As already
described, the evaluation PC software runs an automated
comparison/evaluation of the finger prints. The results of which
have wide application including preventing recognition of machine
wear, quality assurance, maintenance, production data collection,
error evaluation, documentation of the error, delivery status,
condition after software boot up and automatically correcting
errors. In error evaluation for diagnostics, in particular, the
finger prints can be derived when the machine is improperly
running. This is preferably achieved when the machine is running
certain critical procedures, from which conclusions are telling as
to possible errors.
[0017] The building of the fingerprints can be achieved using the
following applications, for example. In the configuration in the
engineering system, for example, there can be obtained the
parameters for the fingerprint. In configuration of the monitoring
points, for example, when it is configured which axis is to be
controlled, parameters for control are sensed. Otherwise, the
parameters may be obtained upon configuration of the observation
parameters (e.g. situation layer, moment actual values, observer
values, application variables, etc.) The fingerprint parameters may
also be developed from the parameters resulting from a start and
stop event for recording projections or over application program
control.
[0018] In another manner, the finger prints can be produced at the
software vendor end. This can be achieved by marking appropriate
attributes of the relevant data/variables during programming of the
software. This is supported by the Engineering System (FIGS. 1,
16b) of the automation component. The measurements may be taken,
for example, from the trace information. In addition, the vendor
can provide for the measurements along with the evaluation software
for evaluation using the evaluation PC. There can be provided, for
example, evaluation software for comparison of the fingerprints.
The application software, software for finger print production
(running in the automation component) and evaluation software
(running in the evaluation PC) can be provided in any of the known,
or equivalent, programming languages, including Java, for
example.
[0019] There are various methods by which the fingerprint
application can be applied. In one method, the fingerprint
application is downloaded through the PC communication connection
to the machine, i.e., automation component. Further, the
application can be applied by deliberate machine service personnel,
via an external service branch. The fingerprint application could
be automatically started by the application program itself. This
could be automatically executed by the application, for example,
during certain maintenance or time intervals or during reequipping
procedures. Additionally, the fingerprint program may be
implemented by remote operation, for example, over the Internet.
Also, the finger print measurement application can be supported
optionally by a deposited workflow. It is also within the invention
that the user manually performs measurement of the fingerprints of
the selected machine and causes the PC to note target/actual
conditions, such as cyclically over a certain length of time, for
example.
[0020] Like all fingerprints, the electronic fingerprints should be
profiled. The first step in profiling of the fingerprints is
achieved by storing the fingerprint in a suitable memory. In the
machine/automation component, for example, the fingerprint can be
stored on Hard Disk or MemCard. Alternatively, the fingerprint can
be stored on the data server of the machine (FIGS. 1, 14), or on
the evaluation PC, by remote file. The fingerprints may even be
stored in additional machine information storage, such as
production data or format information data.
[0021] Once stored, the profiling of the fingerprints continues
with the evaluation process. This may take place in the evaluation
PC and may be accomplished either manually or automatically. From
the results of the analysis adjustments to the machine may be
derived. Composites of "healthy" fingerprints may be stored in
advance in the evaluation software. These may be in the form, for
example, of tolerances of the various machine components. With such
an analysis capability, the fingerprints may evaluated or developed
over time.
[0022] Now that the structure of the present invention has been
described, let us now turn to actual application examples employing
the invention. The following examples illustrate the operation of
the invention in regard to two types of machines, namely the
production machine and the machine tool. In the former, the overall
fingerprinting is concerned with the determination product quality
and the machine quality or with both aspects. In contrast, the
machine tool focuses of the determination of the machine quality,
i.e., machine condition. With many measuring procedures there are
overlapping effects between quality of the processing material and
machine quality and these examples are no exception. In any event,
the following examples are so provided.
[0023] In the first example, a packaging machine is described. It
is desired, for example, to perform a pressure mark correction
procedure, which corrects the pressure mark of the packaging
machine. In this instance, measurements of the process are collated
into an actual value profile. The same measurements can be derived
from a fast pressure mark correction, such as when a fast
correction is driven out. The actual value profile changes can be
compared over time. With such a comparison, the end product can be
influenced directly.
[0024] In the same packaging machine, a real time view of the
motion of the machine may also be viewed. Critical ranges in the
total course of motion with a trace, for example, can be obtained.
This could be performed, for example, with welding seam such as in
foil welding. For example, there may be measurement relevant
parameters for the view process. Or, the parameters measured may be
the target values from control and drive. The measured values may
also be actual values of sensor technology or process variables
from the application.
[0025] There is also provided a kind of test operation by
application of a test drive procedure for testing the machine. In
the test operation, a cyclic machine clock of the packaging machine
with a defined production speed cycles through critical sections of
the course of motion. During which time the present invention
records the relevant actual values that take place.
[0026] The above example is directed more to the operation of the
machine. Here now is a injection moulding machine example where the
emphasis is more on the quality of the product. Here, the injecting
process for a certain tool is examined. With any given tool, there
is normally provided prescription data, such as the profile,
temperature attitude, etc. The prescription data is taken as the
base fingerprint which is compared to actual data received over
certain periods. The data is obtained from the injecting process
from, for example, the manner in which the pressure or strength of
the injection is applied. The values may be compared, for example,
using an integral based averaging algorithm which is applied to
values collected over a predetermined period of time. From the
measured variables, load differences and aging influences of the
tool, for example, can be derived. With this data, the quality of
the end product may be better influenced.
[0027] According to the foregoing description, a fingerprint for a
machine tool or production machine may be derived to determine a
condition of a machine or monitor the quality of the production
machine. With the foregoing fingerprint parameters it is possible
also to troubleshoot problems. In the following there is presented
two simple examples where such machine problems can be pinpointed
by fingerprint measurements. The main technique applied is to
measure the fingerprints periodically and compare the deviations of
the results with the initial measurements.
[0028] As shown in FIG. 3, there is graphically illustrated the
measurements obtained from an operation to change the periodic
error in the pitch of a ball screw. It is assumed, according to the
example, that there is an axis X which is driven by a ball screw.
In addition to the motor measuring system, there is also provided
an additional linear scale along the axis X. The motor measurement
system is used for the closed loop control, whereas the linear
scale is used as a measurement device during this measurement. If
the axis is moved with a constant speed along a certain travel area
X.sub.0, the ideal behavior is shown in FIG. 3.
[0029] The movement X(t) of the axis is ideal to demonstrate the
value of the invention, as inaccuracies during the production
process of the mechanical components of the machine are quite
experienced in the actual world. For instance, it is very often the
case that a real ball screw exhibits a cyclic error in the pitch in
comparison to the ideal. Due to mechanical forces, this error is
magnified over a certain period of time. This situation is shown in
FIG. 5 wherein the cyclic errors in the pitch is shown enlarged and
schematically. It may be, for example, that the error of the ball
screw is enlarged after a certain time of machining due to
mechanical forces
[0030] Now if the error exceeds a certain period of time, the ball
screw should be changed in order to avoid inaccuracies during
machining. These errors can be measured in the following way
according to the present invention. In the first instance, the axis
is moved with a constant speed and only the motor measurement
system is used for closed loop control. In this case, the motor
moves with a constant rotation speed. The constant speed yields to
a constant rotation of the ball screw. The pitch error is
translates to the linear scale, where we have a periodic deviation
from the ideal behavior. This is apparent from the figures.
[0031] In FIG. 6, cyclic deviations of the signal of the direct
measurement system in case of cyclic pitch errors is shown where
the motor measurement system is used for closed loop control. In
this case, the more the errors in the pitch are enlarged, the more
there is likely to be deviations within the signal of the linear
scale. At this time, if the axis is measured periodically in this
way, it is possible to see critical errors before workpieces are
damaged. In other words, it is either possible to change the ball
screw, not after a fixed period of time, but at a point in time
before the critical state is reached or it is possible to change
the compensation values for the pitch screw error
automatically.
[0032] As shown in FIG. 7, in another example, backlash detection
is demonstrated. By means of the same method of the invention
described, it is also possible to detect, for example, a backlash
in a gear box. A backlash may occur due to a build up of mechanical
stresses. For this measurement, we move the axis forward and
backward at a constant speed. Again, only the motor measurement
system is used for closed loop control and the linear scale is used
only for measurement purpose.
[0033] Ideally the X(t) behavior would be as it is shown in FIG. 7.
As shown, X(t) of the direct measurement system includes no
backlash as the axis is moved forward and backward at a constant
speed. The influence of backlash on the measured signal, due to
mechanical wear, for example, can be seen in FIG. 8. As will be
seen, due to the backlash in the system, the axis does not follow
immediately. This is particularly apparent when the motor changes
its rotation direction. At first, the axis stays at its current
position and then moves back with a constant shift.
[0034] From the fingerprint derived, it is apparent that the errors
can be determined earlier than when the critical state is reached
and maintenance can be applied before breakdown of the system. It
is possible, for example, to predict problems arising due to
backlash by periodically repeating the measurement and checking
whether a pattern of critical deviation occurs in comparison to the
initial state of the machine has been reached. In addition, it will
be appreciated that the degree of maintenance can be varied
according to the fingerprint of the present invention. That is,
there are degrees of unhealthiness of a fingerprint and, depending
on the degree, it may be determined that maintenance is not yet
needed. On the other hand, the fingerprint may be employed to
determine minimum maintenance, deciding to allow the machine to
continue to operate under less than optimum conditions, thereby
better managing the maintenance of a machine.
* * * * *