Application Notes

1. Keeping a control on space work

The Astrium test centre near Munich has been working with m+p international vibration control systems for many years.

"Keeping a control on space work" describes the vibration qualification test of a solar panel which is part of the ROCSAT-2 earth oberservation satellite. The final qualification and quasi-static testing of the panel required 108 input channels of which 48 were dynamic strain, 18 force sensors and the others were accelerometers. m+p international's VibExec controller was tasked with running two critical one-off tests and collecting real-time data from all channels for post-test validation analysis. The article was published in the UK Environmental Engineering magazine in Autumn 2003.

2. Titan Mission Helped by m+p international's Force Limiting Controllers

Terry Scharton from JPL describes the variety of sophisticated testing undertaken on the Cassini Huygens spacecraft destined for Saturn's moon, Titan.

As well as a wealth of technical detail there are some great pictures of the testing in progress. Read on...

3. Closed-Loop Acoustic Controller

Guido Bossaert, m+p international, inc., Verona/New Jersey, and Stephen A. Rizzi, NASA Langley Research Center, Hampton/Virigina, describe recent improvements to the acoustic control system of the Thermal Acoustic Fatigue Apparatus, a progressive wave tube test facility at the NASA Langley Research Center in Hampton.
Please read the article "Closed-Loop Control for Sonic Fatigue Testing Systems" published in the Sound & Vibration magazine in November 2001.

4. JPL Relies on m+p international
for Vibration Testing

The Jet Propulsion Laboratory, Pasadena/California used an m+p international vibration control system to qualify the Deep Space 1 (DS1) spacecraft for NASA. The environmental test program for the DS1 spacecraft included a force-limited random vibration test in two axes.

For detailed information on this test, please read the article
"Deep Space 1 Spacecraft Vibration Qualification Testing" published in the Sound & Vibration magazine in March 2001.

5. A New Method of Designing MIL STD (et al) Shock Tests

The following paper briefly reviews the basic requirements for creating a shock pulse time history
suitable for use by digital controllers on electro-dynamic shakers.

In developing a practical test we not only need to meet the various test specification requirements
we also require to do so within the limits of the available test equipment.

Although most specs define pre and post pulse amplitude limits they do not define their shape
or duration. This provides a very powerful opportunity to choose these pre and post pulses
to optimise compensation to suit other system constraints (eg shaker displacement limit) but without
excessive shock spectra distortion or other undesirable side effects. However since there are an infinite number
of possible solutions this process is far from trivial. Also the symmetrical sinusoidal compensation pulses
that are most commonly used may be easy to compute but do not offer much scope for optimisation.

For more information, please read this interesting paper.