Software helps maintain quality control standards

Ford Heavy Truck Development uses DADiSP to ensure that high standards of quality control are maintained.

Ford Heavy Truck Development uses DADiSP to ensure that high standards of quality control are maintained.

Ford Heavy Truck Development in Dearborn, Michigan uses DADiSP for several everyday tasks to improve efficiency and productivity in the area of product development.

As Ford keeps data acquisition and analysis operations in separate departments, we asked Heavy Truck supervisor Rich Bond to describe how DADiSP helps make the "divide-and-conquer" approach to dealing with data both efficient and cost-effective.

Bond's engineers may be called on to work on any component of a vehicle, or they may work on data taken on a complete heavy truck as it travels down a public highway.

As such, a general-purpose tool that can be set up to quickly accommodate the current job is required.

A typical task Bond and his team perform with DADiSP is determining whether resonance occurring in engine-mounted brackets is a result of engine vibration.

Multichannel acceleration data are recorded from the brackets and engine while the engine speed is swept from idle to maximum.

Meanwhile, DADiSP receives data in an empty spreadsheet template while running unattended on a Sun SPARCstation by means of command files built by the engineers.

The resulting time history is broken into small increments for each channel of acceleration data.

Power spectral density plots (PSDs) are performed on these increments; the average rev/min for each increment is calculated; and the PSDs for all increments are combined into a waterfall plot.

As a typical data run is large - over 200,000 points per channel - DADiSP runs overnight to perform these operations and produce a hard copy for the morning.

Before DADiSP, engineers had to extract segments of data manually, perform PSDs by hand on each segment, and then overlay hard copies to obtain a quasi-waterfall plot.

The new method requires significantly fewer hours and fewer people.

As Ford's data are collected in a special department, reduced according to standard algorithms, and passed on to whoever requested them, there are occasionally processing problems resulting from the fact that the people who acquire data may not know how it will be used.

To make matters worse, errors in a data set may be masked if the set is averaged in with a larger sample.

DADiSP provides methods for correcting errors, late in data processing, that used to cause a lot of trouble.

For example, sometimes it is discovered during analysis that the signal to noise ratio of the acquired data is so low that the shape of the data is masked.

It is seldom possible to reacquire the data.

Since the expected shape of the data is usually known from previously verified computer models, there is almost always hope for correction.

Before DADiSP, engineers had to review and reprocess the data, usually in teams of people both from the department that acquired the data and from the department that wanted to analyse them.

This extra step took a long time.

Now, DADiSP's digital filter modules clean up the extra noise.

Information about the expected shape of the data allows one engineer working alone to filter the original signal and separate signal from noise in minimal time.

Before DADiSP was introduced, approximately 40% of data acquisition expenses were associated with the data reduction and analysis stage: it took too long and required too many people.

Data analysis was performed on a mainframe computer, so a job would sit in a queue for a long time, causing delay.

Now that the mainframe programs are being transferred to DADiSP templates, the analysis of one channel of data takes about 10 minutes.

An entire job can run in half a day.

This use of DADiSP has reduced data analysis costs by an estimated 20%.

Rich Bond says he appreciates DADiSP's user-friendliness, which helps make relatively non-trained people productive in very little time.

He mentions the case of an engineer who picked up the product and the manual and within a day or so had a very good template working.

He says his division owns other products similar in function to DADiSP, but that "they just kind of sit there".

When asked why, he responds, "They are a language; DADiSP has an intuitive feel for how things go.

You can actually see things".

Bond mentions that he appreciates DADiSP's ability to handle enormous data files.

He says that some of the data acquisition runs produce huge sets, consisting of 160 seconds' worth of data sampled at 8000Hz per channel for 15 minutes.

Other runs at lower sampling rates can last up to two hours.

He says he and his engineers have no qualms about using DADiSP to handle these large sets when they have to analyse a long run.

Most important to Bond is DADiSP's capability for running unattended by means of command files.

"To put a workstation on an engineer's desk with all the network support behind it, you spend about $50,000 to $70,000.

Therefore, the computer has got to be running all the time.

It can't work eight-to-five, like the engineer does.

DADiSP makes it possible for an engineer to hit the button to turn the program on at the end of the day, walk out of here, then come in the morning and find the work all done".

He feels it is extremely valuable to have the computer working while the engineer is not.

DADiSP is supplied and supported in the UK and Ireland by Adept Scientific.

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