A wire transducer in a system with a van der Pol oscillator and velocity feedback

Abstract

The work concerns wire transducers, which use a system with a van der Pol oscillator with the aim of maintaining nondecreasing natural vibrations in the wire. As opposed to classical solutions, in which the feedback signal of the oscillator contains the course of displacement and velocity of the vibrating mass, a simple solution based only on the course of velocity is used. Such a solution is more advantageous from a practical perspective as regards to physical systems because, in the case of velocity transducers, it eliminates the need to integrate the signal and the problems connected with it.Particular places for this solution may be found in wire tensometer systems designated for the long-term constant measurement, as well as for the measurement of time-variable courses, including those of a chaotic character.In the work, analysis was conducted on a modified van der Pol equation adapted for the movement of a discrete mass for the determination conditions of the existence of a limit cycle, the vibration course, as well as the definition of the capabilities of adapting the results in the case of a wire transducer.The results of theoretical analysis were confirmed by the results of the experimental tests conducted on a laboratory model constructed for this purpose.

Measurements of Dynamic Deformations of Building Structures by Applying Wire Sensors

“…The scheme of the system, in which the sensor coils, the cables, the source of the drive coil supply, and other equivalent parts of the wire are exposed, is presented in Figure 3. The meaning of the equivalent mass and the remaining equivalent parameters of the vibrating wire are described in detail in Reference [21].…”

“…Two new solutions of vibrating wire sensors, which undertake the task of meeting the requirements of building engineering are described in References [20,21,22]. Both solutions utilize self-exciting vibrations, the first one is based on the van der Pol generator, while the second one on the impulse exciter.…”

Influence of Cable Length on the Vibrating Wire Sensors Dynamic Measurements

“…Example frames from frame-based animation obtained from data processing for the lower crosssection in the second series of measurements[12] Example of measured strains for 20 second period and the slope of measured plane in selected moment of measuring[12] Two new domestic solutions of vibrating wire sensors, which are undertaking the task of meeting the requirements of building engineering are shown in[4][5][6]. Both solutions utilise self-exciting vibrations, the first one is based on the van der Pol generator, while the second one on the impulse exciter.…”