US 20060085091 A9
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.
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
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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.
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25. A computer readable product having encoded therein instructions for driving a computer processor according to the steps of
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.
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.
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.
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.
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A separate user interface 16 b provides a user interface with an engineering system (setup, configuration, programming) for the automation component. The user interfaces 16 a and 16 b 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.
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.
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.
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.
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.
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.
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.
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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
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.
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.
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 (
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.
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 (
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.
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.
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.
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.
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.
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.
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.
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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
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.
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Ideally the X(t) behavior would be as it is shown in
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.