As smart devices of all types increasingly proliferate throughout the creations of system and product designers, it seemed to be a good time to find out what engineers really thought about these intelligent instruments and their potential for use in self-healing machine designs.
Anoop Malaviya, principal engineer, ICT at Norman Disney &Young, noted that this concept is hardly new. "In the 1990s there was a bigthrust promoted by IEEE Control Society to use artificial intelligence fordesign of systems. The result was a range of design approaches broadly calledintelligent (or autonomous) systems. These ‘self-healing' systems would monitoroperations against parametric shift andadjust set-points as rules required to adjust to new situations."
Adding to Malaviya's comment was a note from Preston Johnson,platform manager, condition monitoring systems at National Instruments. Johnsonnoted that fuzzy logic has been used to implement vibration diagnosticexpertise into vibration monitoring systems. "Error codes, process values andrelated sensors can be coupled with a fuzzy logic execution system to determinea suggested course of action, perhaps one that can be acted out automaticallyby the control/monitoring system," he said.
With the technology's clear roots in computer science, embeddeddesign engineer Ben Morse's comments were very appropriate. "Another tool thatcan be used here is Forward Error Correction (FEC). This means using extraspace to store redundant data. If there is a corruption in memory, theredundant data can be used to reconstruct the original data perfectly. The moreredundant data you store, the more corruptions you can recover from. CD-ROMdiscs use FEC so that they can survive a small scratch and still playperfectly."
As for actual system designapplication examples, Dinesh Patel, president of BatchTest Systems, noted thatin some of his company's smart automated production testers, an algorithm isused to detect faulty internal data acquisition cards and automatically switchto good cards. To do this, two sets of DAQ cards are installed, said Patel."When a repeated failure is detected during DAQ_A usage, the tester performs aquick self-test between DAQ_A and DAQ_B. If that fails too, then the testerswitches to using DAQ_B and retests. DAQ_A is then freed up to be replaced or serviced."
Though this approach has proven to work well, Patel cautions thatit is not cost-effective and that many clients are not willing to pay forexpensive redundant hardware since the data acquisition board failure rate isalready low due to use of signal conditioning modules.
Design News and National Instruments willbe hosting a roundtable discussion on this topic via Webcast in late April. Click here for moreinformation.
Transfers the control of a large number of motion axes from one numerical control kernel to another within a CNC system, using multiple NCKs, and enables implement control schemes for virtually any type of machine tool.
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