The Jaguar closed-loop vibration control system is a powerful vibration controller, which according to its makers, significantly raises industry standards for speed, channel count, processing power and convenience.
The Jaguar is a workstation-based, distributed-process solution for structural, acoustic and closed-loop vibration control. The system controls the shaker table(s) that simulate vibration stress, takes measurements from the object under test and displays results such as transfer functions and PSDs (power spectral densities) in realtime.
The system's sampling rate is independent of channel count. Whether it is measuring 32 or 320 channels, the Jaguar acquires data at sampling rates up to 100 000 per second. By comparison, most systems in use today take 51 200 samples/s. Spectral Dynamics says that systems capable of 100 000 samples per second are generally limited to four or six channels.
The advantages of the system are particularly relevant to aerospace engineers who need large numbers of channels to monitor vibration at many points on satellites and other large, complex space structures. When simulating explosive events, such as rocket booster-stage separation, they need 100 000 samples/s to accurately measure events occurring at 10 000 cycles per second. Because of tight launch schedules and competition for laboratory facilities or prototypes, they need results quickly, not a couple of days or a week after testing.
Several aerospace agencies and commercial developers ordered Jaguar Vibration Control Systems from Spectral Dynamics before the product officially hit the market. Among the companies are SNECMA (France), SNIA and Alenia Aerospazio (Italy), NASDA (Japan), Boeing and ITT (USA) and INPE, the Brazilian space agency.
In terms of channel count, the Jaguar is practically unlimited. The Brazilian space agency, for example, has ordered three systems, one of which features 320 channels. Users expand the system by adding ten-channel cards (called acquisition control peripheral modules). Each card incorporates multiple 32 bit DSP processors which increases system intelligence as channels are added. The Jaguar's distributed processing architecture allows users to link many modules via a high-speed, 100Base-T Ethernet.
Automotive manufacturers also face intense pressure to shorten product development cycles. Because the Jaguar displays results while the test is running, and permits instant detection of flawed or incorrect data or other test problems, the system can deliver major time savings in tasks such as modal analysis or detailed vibration/acoustic analysis of new car prototypes.
With conventional equipment, it might take two to three weeks to analyse the mountain of data acquired by monitoring hundreds of channels at 100 000 samples/s. With the Jaguar, however, data reduction occurs parallel with data acquisition. Transfer functions and PSDs appear on the screen in realtime while the test is underway. Results are available as soon as the test is concluded.
The second product from Spectral Dynamics is the Puma. This is a controller with some very important differences. Some of the Puma's features are:
p A 90 dB control dynamic range coupled with auto-ranging output attenuators keeps tests within control tolerances, even if the dynamics of the shaker fixture are less than ideal.
p Accurate measurements by combining 7-pole analog anti-aliasing filters. Sigma Delta A/D converters and sharp digital filters to guarantee that all input alias components are eliminated.
p Fast 32 bit floating-point DSPs for high-speed parallel processing and high accuracy - previously only available in very expensive systems.
p Patented control algorithms offering the optimum speed and accuracy. The Puma is a complete vibration test solution that meets the most stringent needs for environmental test simulation.
The third product is the SC15 budget 2-channel dynamic analyser designed to fit into a notebook. It is suited for those setting out on the road to vibration analysis, the SC15 allows frequency domain analysis to 2 kHz. The built-in trigger function allows the capturing of transient events for examination in the time domain, and subsequently frequency domain analysis. Advanced dual cursors and harmonic cursors allow comprehensive measurements to be made. A unique data calibration file structure allows quick access to commonly used transducers and the ICP supply permits the use of transducers with integral electronics.
It also has a UFF export feature which is designed to apply the correct labelling format for export to Star Modal. Coupled with Star (another Spectral Dynamics product), the combination offers a low-cost entry into the field of modal analysis.
Spectral Dynamics is a leading worldwide supplier of systems and software for vibration testing, structural dynamics and acoustic analysis. Its products are locally distributed by Spescom MeasureGraph.
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