Most linear measurement is static, and is performed on something that is unchanging and stable – at least for a short period of time. Dynamic measurement, on the other hand, is the continuous monitoring of a changing quantity. In other words, the physical quantity being measured varies over time.
The term ‘dynamic measurement’ can be misleading as it is often only applied to the measurement of quantities which are time-dependant. However, the most imporant distinguishing feature of this type of measurement, as opposed to static measurement, is the speed of response of the measurement system compared to the speed at which the measured signal is changing.
Examples include the measurement of a mechanical force or acceleration, vibration, pressure, strain, electrical high-voltage impulses or time-dependent temperature, and it is often used as a measurement method in the fields of research, development, test and evaluation.
Dynamic measurements are carried out by accelerometers and shock sensors which have been specifically created to provide accurate measurements and diagnostic information in a broad range of industries.
One of the areas in which dynamic measurement is most commonly used is in the automotive industry. Here is it used for crush and crash safety testing as well as analyzing the drive and handling characteristics of the vehicle. It is used to measure bank angle, vertical acceleration, lateral acceleration and X and Y axis acceleration. This data is then used to enhance the car’s performance during highly dynamic maneuvers, such as sharp turns.
Other indutries where this technology is widely used include:
* Air blast pressure measurement
* Software development
* Transducer manufacture
* Pump manufacture
* Testing equipment manufacture
* Explosives industry
* Aeronautical engineering – in-flight gas turbine vibration monitoring
* Medical – activity monitoring in pacemakers.
* Aerospace industry – impact monitoring of the space shuttle
A dynamic measurement system should ideally be designed so that its output signal is proportional to the input signal. Often, however, this is only achieved for input signals with a low-frequency spectrum. For input signals with large bandwidth, the output signal of the measurement system is no longer proportional to its input signal. This can cause what is known as dynamic error. To compensate for this, post-processing of the output of the measurement system needs to be carried out using digital filtering.
Watson Industries manufactures a wide range of accelerometers and other sensors for accurate dynamic measurements. Go to www.watson-gyro.com for more information.
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