Laser Doppler Vibrometry system for measurement of vibration/velocity
| Grant number: | 10/13868-0 |
| Support type: | Scholarships in Brazil - Master |
| Effective date (Start): | March 01, 2011 |
| Effective date (End): | February 28, 2013 |
| Field of knowledge: | Engineering - Electrical Engineering |
| Principal Investigator: | Ricardo Tokio Higuti |
| Grantee: | Paula Lalucci Berton |
| Home Institution: | Faculdade de Engenharia (FEIS). Universidade Estadual Paulista (UNESP). Campus de Ilha Solteira. Ilha Solteira , SP, Brazil |
| Associated scholarship(s): | 12/02148-2 - Laser Doppler Vibrometry system for measurement of vibration/velocity, BE.EP.MS |
Abstract Optical interferometry is a well-established method for the measurement of micro- and nanodisplacements and vibrations. The displacement information is contained in the instantaneous phase of the photodetected signal, which can be subject to fading, that makes it difficult its correct detection. In general, optical phase interferometric measurement methods demand expensive optical circuits and hardware. On the other side, digital signal processors (DSPs) systems allow the acquisition and processing of the photodetected signal in real time and with lower cost. In this work the integration of an interferometric system, based on a homodine Michelson interferometer, with a DSP system, is proposed. Important topics to be addressed are: study and evaluate phase demodulation techniques that are more adequate for the proposed implementation, in general based on a spectral analysis of the signals, observing effects such as dynamic range, random and quantization noise, and real time implementation; fixed- and floating-point DSP platforms will be evaluated for the acquisition and signal processing of the photodetected signals. These results will be compared to those obtained with a traditional laboratory setup: oscilloscope for data acquisition, data transfer to computer for post-processing in Matlab. The use of the DSP system will reduce the cost of the interferometric system, and allow faster and more automatic measurements. The realization of several measurements per second will allow the rapid and denser transfer functions and linearity curves tracing, making easier the analysis of hysteresis and saturation effects, for example, even in the presence of fading. | |