Production line NVH powertrain testing advanced

Athony Best Dynamics has been developing NVH systems further, particularly for 'end-of-line' and 'off-line' audit for powertrain and power steering testing systems for production.

Anthony Best Dynamics reports that it has been working hard to further strengthen its Plato products' position as a world-leading objective noise/vibration measurement and analysis system for powertrain and power steering testing for: * End-of-line.

* Off-line audit.

* R and D.

* Durability.

* In-vehicle.

* Pass-by.

Here are some of the highlights from the new version.

* Pass-by noise analysis - some years back, we developed a hardware/software solution within Plato for pass-by noise analysis.

It enabled development engineers to produce regular (overall level) type results as well as utilise very accurate Doppler-shift correction to facilitate narrow-band order-analysis for effective tonal noise source identification during the drive-by test.

The novel feature of the system was that a radar (usually required to measure vehicle position and speed throughout the test) was not required, promoting a very cost-effective and easy to set-up solution on the test track.

We have kept the philosophy of the system the same, but the software has now been brought fully up-to-date and is now available as a sub-product 'add-on' to Plato called 'PassBy'.

The hardware remains the same, so if you are an existing user, all you will need is the latest software.

* Synchronous-event ('knock' and 'click') Analysis for 'hot' engine test - to-date, V''s RevKit sub-product for objective synchronous-event (knock and click) analysis has been applied to the testing of products such as transmissions, axles, transfer cases etc, where all knock and click type noises/vibrations can be considered as 'unexpected'.

Pass/fail metrics have therefore been based on absolute levels, and in particular, on the premise that higher noise/vibration levels are equated with lower product qualities.

However, some categories of products, such as engines, produce noise/vibration signatures which inherently contain significant transient event components that are synchronous to shaft speed, so an absolute level based assessment becomes unsuitable.

To facilitate testing of these types of products, RevKit has been enhanced to allow 'normal' reference signatures to be learnt and a bi-directional (difference from reference level) analysis to be be performed.

This then: * Exposes differences in low level response areas that are indicative of product quality change (even though the absolute response level may remain low).

* Allows the system to track when a product is becoming 'quieter' as well as 'noisier', which can also provide valuable indications of product quality; a prerequisite for any long-term endurance type testing.

* Synchronous-event ('knock' and 'click') summary view - this new view type allows you to effectively summarise the occurrence of knock and click type events, while at the same time allowing you to home-in on specific manufacturing issues by product serial number and/or date/time filtering.

A main 3D display with X-Y cursors is accompanied by X and Y 2D-slice displays; a format that we have found to be very useful for data visualisation within other areas of Plato.

* Production test cycle logging - we have been implementing fast production test cycles for over 20 years now and we know that in the high volume manufacturing business every second counts.

Therefore, to assist cycle-time optimisation, we have now added a production test time logging facility to Plato that will show you exactly where time is being spent in the test cycle - averaged over a number of cycles.

Histograms can be produced that show you exactly how much time Plato used for data capture and processing etc, as well as how much time was spent waiting for the operators or the test stand etc.

* Calibration reporting - we have added an automatic report generation function to our dynamic channel calibration action, so that when you've calibrated each channel you can create a report that includes channel title, scales factor and RMS-level/spectral graphics etc to fully document your current set-up.

* Finally - Anthony Best Dynamics has added a Constant Frequency (Hz) Cursor to our Order Campbell (Spectrogram) View - invaluable for identifying resonance type phenomena whilst viewing data in the order domain.

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